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TOMOYO Linux Cross Reference
Linux/net/packet/af_packet.c

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  1 /*
  2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  3  *              operating system.  INET is implemented using the  BSD Socket
  4  *              interface as the means of communication with the user level.
  5  *
  6  *              PACKET - implements raw packet sockets.
  7  *
  8  * Authors:     Ross Biro
  9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 10  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 11  *
 12  * Fixes:
 13  *              Alan Cox        :       verify_area() now used correctly
 14  *              Alan Cox        :       new skbuff lists, look ma no backlogs!
 15  *              Alan Cox        :       tidied skbuff lists.
 16  *              Alan Cox        :       Now uses generic datagram routines I
 17  *                                      added. Also fixed the peek/read crash
 18  *                                      from all old Linux datagram code.
 19  *              Alan Cox        :       Uses the improved datagram code.
 20  *              Alan Cox        :       Added NULL's for socket options.
 21  *              Alan Cox        :       Re-commented the code.
 22  *              Alan Cox        :       Use new kernel side addressing
 23  *              Rob Janssen     :       Correct MTU usage.
 24  *              Dave Platt      :       Counter leaks caused by incorrect
 25  *                                      interrupt locking and some slightly
 26  *                                      dubious gcc output. Can you read
 27  *                                      compiler: it said _VOLATILE_
 28  *      Richard Kooijman        :       Timestamp fixes.
 29  *              Alan Cox        :       New buffers. Use sk->mac.raw.
 30  *              Alan Cox        :       sendmsg/recvmsg support.
 31  *              Alan Cox        :       Protocol setting support
 32  *      Alexey Kuznetsov        :       Untied from IPv4 stack.
 33  *      Cyrus Durgin            :       Fixed kerneld for kmod.
 34  *      Michal Ostrowski        :       Module initialization cleanup.
 35  *         Ulises Alonso        :       Frame number limit removal and
 36  *                                      packet_set_ring memory leak.
 37  *              Eric Biederman  :       Allow for > 8 byte hardware addresses.
 38  *                                      The convention is that longer addresses
 39  *                                      will simply extend the hardware address
 40  *                                      byte arrays at the end of sockaddr_ll
 41  *                                      and packet_mreq.
 42  *              Johann Baudy    :       Added TX RING.
 43  *              Chetan Loke     :       Implemented TPACKET_V3 block abstraction
 44  *                                      layer.
 45  *                                      Copyright (C) 2011, <lokec@ccs.neu.edu>
 46  *
 47  *
 48  *              This program is free software; you can redistribute it and/or
 49  *              modify it under the terms of the GNU General Public License
 50  *              as published by the Free Software Foundation; either version
 51  *              2 of the License, or (at your option) any later version.
 52  *
 53  */
 54 
 55 #include <linux/types.h>
 56 #include <linux/mm.h>
 57 #include <linux/capability.h>
 58 #include <linux/fcntl.h>
 59 #include <linux/socket.h>
 60 #include <linux/in.h>
 61 #include <linux/inet.h>
 62 #include <linux/netdevice.h>
 63 #include <linux/if_packet.h>
 64 #include <linux/wireless.h>
 65 #include <linux/kernel.h>
 66 #include <linux/kmod.h>
 67 #include <linux/slab.h>
 68 #include <linux/vmalloc.h>
 69 #include <net/net_namespace.h>
 70 #include <net/ip.h>
 71 #include <net/protocol.h>
 72 #include <linux/skbuff.h>
 73 #include <net/sock.h>
 74 #include <linux/errno.h>
 75 #include <linux/timer.h>
 76 #include <linux/uaccess.h>
 77 #include <asm/ioctls.h>
 78 #include <asm/page.h>
 79 #include <asm/cacheflush.h>
 80 #include <asm/io.h>
 81 #include <linux/proc_fs.h>
 82 #include <linux/seq_file.h>
 83 #include <linux/poll.h>
 84 #include <linux/module.h>
 85 #include <linux/init.h>
 86 #include <linux/mutex.h>
 87 #include <linux/if_vlan.h>
 88 #include <linux/virtio_net.h>
 89 #include <linux/errqueue.h>
 90 #include <linux/net_tstamp.h>
 91 #include <linux/percpu.h>
 92 #ifdef CONFIG_INET
 93 #include <net/inet_common.h>
 94 #endif
 95 #include <linux/bpf.h>
 96 #include <net/compat.h>
 97 
 98 #include "internal.h"
 99 
100 /*
101    Assumptions:
102    - if device has no dev->hard_header routine, it adds and removes ll header
103      inside itself. In this case ll header is invisible outside of device,
104      but higher levels still should reserve dev->hard_header_len.
105      Some devices are enough clever to reallocate skb, when header
106      will not fit to reserved space (tunnel), another ones are silly
107      (PPP).
108    - packet socket receives packets with pulled ll header,
109      so that SOCK_RAW should push it back.
110 
111 On receive:
112 -----------
113 
114 Incoming, dev->hard_header!=NULL
115    mac_header -> ll header
116    data       -> data
117 
118 Outgoing, dev->hard_header!=NULL
119    mac_header -> ll header
120    data       -> ll header
121 
122 Incoming, dev->hard_header==NULL
123    mac_header -> UNKNOWN position. It is very likely, that it points to ll
124                  header.  PPP makes it, that is wrong, because introduce
125                  assymetry between rx and tx paths.
126    data       -> data
127 
128 Outgoing, dev->hard_header==NULL
129    mac_header -> data. ll header is still not built!
130    data       -> data
131 
132 Resume
133   If dev->hard_header==NULL we are unlikely to restore sensible ll header.
134 
135 
136 On transmit:
137 ------------
138 
139 dev->hard_header != NULL
140    mac_header -> ll header
141    data       -> ll header
142 
143 dev->hard_header == NULL (ll header is added by device, we cannot control it)
144    mac_header -> data
145    data       -> data
146 
147    We should set nh.raw on output to correct posistion,
148    packet classifier depends on it.
149  */
150 
151 /* Private packet socket structures. */
152 
153 /* identical to struct packet_mreq except it has
154  * a longer address field.
155  */
156 struct packet_mreq_max {
157         int             mr_ifindex;
158         unsigned short  mr_type;
159         unsigned short  mr_alen;
160         unsigned char   mr_address[MAX_ADDR_LEN];
161 };
162 
163 union tpacket_uhdr {
164         struct tpacket_hdr  *h1;
165         struct tpacket2_hdr *h2;
166         struct tpacket3_hdr *h3;
167         void *raw;
168 };
169 
170 static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
171                 int closing, int tx_ring);
172 
173 #define V3_ALIGNMENT    (8)
174 
175 #define BLK_HDR_LEN     (ALIGN(sizeof(struct tpacket_block_desc), V3_ALIGNMENT))
176 
177 #define BLK_PLUS_PRIV(sz_of_priv) \
178         (BLK_HDR_LEN + ALIGN((sz_of_priv), V3_ALIGNMENT))
179 
180 #define BLOCK_STATUS(x) ((x)->hdr.bh1.block_status)
181 #define BLOCK_NUM_PKTS(x)       ((x)->hdr.bh1.num_pkts)
182 #define BLOCK_O2FP(x)           ((x)->hdr.bh1.offset_to_first_pkt)
183 #define BLOCK_LEN(x)            ((x)->hdr.bh1.blk_len)
184 #define BLOCK_SNUM(x)           ((x)->hdr.bh1.seq_num)
185 #define BLOCK_O2PRIV(x) ((x)->offset_to_priv)
186 #define BLOCK_PRIV(x)           ((void *)((char *)(x) + BLOCK_O2PRIV(x)))
187 
188 struct packet_sock;
189 static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
190                        struct packet_type *pt, struct net_device *orig_dev);
191 
192 static void *packet_previous_frame(struct packet_sock *po,
193                 struct packet_ring_buffer *rb,
194                 int status);
195 static void packet_increment_head(struct packet_ring_buffer *buff);
196 static int prb_curr_blk_in_use(struct tpacket_block_desc *);
197 static void *prb_dispatch_next_block(struct tpacket_kbdq_core *,
198                         struct packet_sock *);
199 static void prb_retire_current_block(struct tpacket_kbdq_core *,
200                 struct packet_sock *, unsigned int status);
201 static int prb_queue_frozen(struct tpacket_kbdq_core *);
202 static void prb_open_block(struct tpacket_kbdq_core *,
203                 struct tpacket_block_desc *);
204 static void prb_retire_rx_blk_timer_expired(struct timer_list *);
205 static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *);
206 static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *);
207 static void prb_clear_rxhash(struct tpacket_kbdq_core *,
208                 struct tpacket3_hdr *);
209 static void prb_fill_vlan_info(struct tpacket_kbdq_core *,
210                 struct tpacket3_hdr *);
211 static void packet_flush_mclist(struct sock *sk);
212 static u16 packet_pick_tx_queue(struct sk_buff *skb);
213 
214 struct packet_skb_cb {
215         union {
216                 struct sockaddr_pkt pkt;
217                 union {
218                         /* Trick: alias skb original length with
219                          * ll.sll_family and ll.protocol in order
220                          * to save room.
221                          */
222                         unsigned int origlen;
223                         struct sockaddr_ll ll;
224                 };
225         } sa;
226 };
227 
228 #define vio_le() virtio_legacy_is_little_endian()
229 
230 #define PACKET_SKB_CB(__skb)    ((struct packet_skb_cb *)((__skb)->cb))
231 
232 #define GET_PBDQC_FROM_RB(x)    ((struct tpacket_kbdq_core *)(&(x)->prb_bdqc))
233 #define GET_PBLOCK_DESC(x, bid) \
234         ((struct tpacket_block_desc *)((x)->pkbdq[(bid)].buffer))
235 #define GET_CURR_PBLOCK_DESC_FROM_CORE(x)       \
236         ((struct tpacket_block_desc *)((x)->pkbdq[(x)->kactive_blk_num].buffer))
237 #define GET_NEXT_PRB_BLK_NUM(x) \
238         (((x)->kactive_blk_num < ((x)->knum_blocks-1)) ? \
239         ((x)->kactive_blk_num+1) : 0)
240 
241 static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
242 static void __fanout_link(struct sock *sk, struct packet_sock *po);
243 
244 static int packet_direct_xmit(struct sk_buff *skb)
245 {
246         return dev_direct_xmit(skb, packet_pick_tx_queue(skb));
247 }
248 
249 static struct net_device *packet_cached_dev_get(struct packet_sock *po)
250 {
251         struct net_device *dev;
252 
253         rcu_read_lock();
254         dev = rcu_dereference(po->cached_dev);
255         if (likely(dev))
256                 dev_hold(dev);
257         rcu_read_unlock();
258 
259         return dev;
260 }
261 
262 static void packet_cached_dev_assign(struct packet_sock *po,
263                                      struct net_device *dev)
264 {
265         rcu_assign_pointer(po->cached_dev, dev);
266 }
267 
268 static void packet_cached_dev_reset(struct packet_sock *po)
269 {
270         RCU_INIT_POINTER(po->cached_dev, NULL);
271 }
272 
273 static bool packet_use_direct_xmit(const struct packet_sock *po)
274 {
275         return po->xmit == packet_direct_xmit;
276 }
277 
278 static u16 __packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb,
279                                   struct net_device *sb_dev)
280 {
281         return dev_pick_tx_cpu_id(dev, skb, sb_dev, NULL);
282 }
283 
284 static u16 packet_pick_tx_queue(struct sk_buff *skb)
285 {
286         struct net_device *dev = skb->dev;
287         const struct net_device_ops *ops = dev->netdev_ops;
288         u16 queue_index;
289 
290         if (ops->ndo_select_queue) {
291                 queue_index = ops->ndo_select_queue(dev, skb, NULL,
292                                                     __packet_pick_tx_queue);
293                 queue_index = netdev_cap_txqueue(dev, queue_index);
294         } else {
295                 queue_index = __packet_pick_tx_queue(dev, skb, NULL);
296         }
297 
298         return queue_index;
299 }
300 
301 /* __register_prot_hook must be invoked through register_prot_hook
302  * or from a context in which asynchronous accesses to the packet
303  * socket is not possible (packet_create()).
304  */
305 static void __register_prot_hook(struct sock *sk)
306 {
307         struct packet_sock *po = pkt_sk(sk);
308 
309         if (!po->running) {
310                 if (po->fanout)
311                         __fanout_link(sk, po);
312                 else
313                         dev_add_pack(&po->prot_hook);
314 
315                 sock_hold(sk);
316                 po->running = 1;
317         }
318 }
319 
320 static void register_prot_hook(struct sock *sk)
321 {
322         lockdep_assert_held_once(&pkt_sk(sk)->bind_lock);
323         __register_prot_hook(sk);
324 }
325 
326 /* If the sync parameter is true, we will temporarily drop
327  * the po->bind_lock and do a synchronize_net to make sure no
328  * asynchronous packet processing paths still refer to the elements
329  * of po->prot_hook.  If the sync parameter is false, it is the
330  * callers responsibility to take care of this.
331  */
332 static void __unregister_prot_hook(struct sock *sk, bool sync)
333 {
334         struct packet_sock *po = pkt_sk(sk);
335 
336         lockdep_assert_held_once(&po->bind_lock);
337 
338         po->running = 0;
339 
340         if (po->fanout)
341                 __fanout_unlink(sk, po);
342         else
343                 __dev_remove_pack(&po->prot_hook);
344 
345         __sock_put(sk);
346 
347         if (sync) {
348                 spin_unlock(&po->bind_lock);
349                 synchronize_net();
350                 spin_lock(&po->bind_lock);
351         }
352 }
353 
354 static void unregister_prot_hook(struct sock *sk, bool sync)
355 {
356         struct packet_sock *po = pkt_sk(sk);
357 
358         if (po->running)
359                 __unregister_prot_hook(sk, sync);
360 }
361 
362 static inline struct page * __pure pgv_to_page(void *addr)
363 {
364         if (is_vmalloc_addr(addr))
365                 return vmalloc_to_page(addr);
366         return virt_to_page(addr);
367 }
368 
369 static void __packet_set_status(struct packet_sock *po, void *frame, int status)
370 {
371         union tpacket_uhdr h;
372 
373         h.raw = frame;
374         switch (po->tp_version) {
375         case TPACKET_V1:
376                 h.h1->tp_status = status;
377                 flush_dcache_page(pgv_to_page(&h.h1->tp_status));
378                 break;
379         case TPACKET_V2:
380                 h.h2->tp_status = status;
381                 flush_dcache_page(pgv_to_page(&h.h2->tp_status));
382                 break;
383         case TPACKET_V3:
384                 h.h3->tp_status = status;
385                 flush_dcache_page(pgv_to_page(&h.h3->tp_status));
386                 break;
387         default:
388                 WARN(1, "TPACKET version not supported.\n");
389                 BUG();
390         }
391 
392         smp_wmb();
393 }
394 
395 static int __packet_get_status(struct packet_sock *po, void *frame)
396 {
397         union tpacket_uhdr h;
398 
399         smp_rmb();
400 
401         h.raw = frame;
402         switch (po->tp_version) {
403         case TPACKET_V1:
404                 flush_dcache_page(pgv_to_page(&h.h1->tp_status));
405                 return h.h1->tp_status;
406         case TPACKET_V2:
407                 flush_dcache_page(pgv_to_page(&h.h2->tp_status));
408                 return h.h2->tp_status;
409         case TPACKET_V3:
410                 flush_dcache_page(pgv_to_page(&h.h3->tp_status));
411                 return h.h3->tp_status;
412         default:
413                 WARN(1, "TPACKET version not supported.\n");
414                 BUG();
415                 return 0;
416         }
417 }
418 
419 static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec *ts,
420                                    unsigned int flags)
421 {
422         struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
423 
424         if (shhwtstamps &&
425             (flags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
426             ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts))
427                 return TP_STATUS_TS_RAW_HARDWARE;
428 
429         if (ktime_to_timespec_cond(skb->tstamp, ts))
430                 return TP_STATUS_TS_SOFTWARE;
431 
432         return 0;
433 }
434 
435 static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame,
436                                     struct sk_buff *skb)
437 {
438         union tpacket_uhdr h;
439         struct timespec ts;
440         __u32 ts_status;
441 
442         if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
443                 return 0;
444 
445         h.raw = frame;
446         switch (po->tp_version) {
447         case TPACKET_V1:
448                 h.h1->tp_sec = ts.tv_sec;
449                 h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
450                 break;
451         case TPACKET_V2:
452                 h.h2->tp_sec = ts.tv_sec;
453                 h.h2->tp_nsec = ts.tv_nsec;
454                 break;
455         case TPACKET_V3:
456                 h.h3->tp_sec = ts.tv_sec;
457                 h.h3->tp_nsec = ts.tv_nsec;
458                 break;
459         default:
460                 WARN(1, "TPACKET version not supported.\n");
461                 BUG();
462         }
463 
464         /* one flush is safe, as both fields always lie on the same cacheline */
465         flush_dcache_page(pgv_to_page(&h.h1->tp_sec));
466         smp_wmb();
467 
468         return ts_status;
469 }
470 
471 static void *packet_lookup_frame(struct packet_sock *po,
472                 struct packet_ring_buffer *rb,
473                 unsigned int position,
474                 int status)
475 {
476         unsigned int pg_vec_pos, frame_offset;
477         union tpacket_uhdr h;
478 
479         pg_vec_pos = position / rb->frames_per_block;
480         frame_offset = position % rb->frames_per_block;
481 
482         h.raw = rb->pg_vec[pg_vec_pos].buffer +
483                 (frame_offset * rb->frame_size);
484 
485         if (status != __packet_get_status(po, h.raw))
486                 return NULL;
487 
488         return h.raw;
489 }
490 
491 static void *packet_current_frame(struct packet_sock *po,
492                 struct packet_ring_buffer *rb,
493                 int status)
494 {
495         return packet_lookup_frame(po, rb, rb->head, status);
496 }
497 
498 static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc)
499 {
500         del_timer_sync(&pkc->retire_blk_timer);
501 }
502 
503 static void prb_shutdown_retire_blk_timer(struct packet_sock *po,
504                 struct sk_buff_head *rb_queue)
505 {
506         struct tpacket_kbdq_core *pkc;
507 
508         pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
509 
510         spin_lock_bh(&rb_queue->lock);
511         pkc->delete_blk_timer = 1;
512         spin_unlock_bh(&rb_queue->lock);
513 
514         prb_del_retire_blk_timer(pkc);
515 }
516 
517 static void prb_setup_retire_blk_timer(struct packet_sock *po)
518 {
519         struct tpacket_kbdq_core *pkc;
520 
521         pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
522         timer_setup(&pkc->retire_blk_timer, prb_retire_rx_blk_timer_expired,
523                     0);
524         pkc->retire_blk_timer.expires = jiffies;
525 }
526 
527 static int prb_calc_retire_blk_tmo(struct packet_sock *po,
528                                 int blk_size_in_bytes)
529 {
530         struct net_device *dev;
531         unsigned int mbits = 0, msec = 0, div = 0, tmo = 0;
532         struct ethtool_link_ksettings ecmd;
533         int err;
534 
535         rtnl_lock();
536         dev = __dev_get_by_index(sock_net(&po->sk), po->ifindex);
537         if (unlikely(!dev)) {
538                 rtnl_unlock();
539                 return DEFAULT_PRB_RETIRE_TOV;
540         }
541         err = __ethtool_get_link_ksettings(dev, &ecmd);
542         rtnl_unlock();
543         if (!err) {
544                 /*
545                  * If the link speed is so slow you don't really
546                  * need to worry about perf anyways
547                  */
548                 if (ecmd.base.speed < SPEED_1000 ||
549                     ecmd.base.speed == SPEED_UNKNOWN) {
550                         return DEFAULT_PRB_RETIRE_TOV;
551                 } else {
552                         msec = 1;
553                         div = ecmd.base.speed / 1000;
554                 }
555         }
556 
557         mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
558 
559         if (div)
560                 mbits /= div;
561 
562         tmo = mbits * msec;
563 
564         if (div)
565                 return tmo+1;
566         return tmo;
567 }
568 
569 static void prb_init_ft_ops(struct tpacket_kbdq_core *p1,
570                         union tpacket_req_u *req_u)
571 {
572         p1->feature_req_word = req_u->req3.tp_feature_req_word;
573 }
574 
575 static void init_prb_bdqc(struct packet_sock *po,
576                         struct packet_ring_buffer *rb,
577                         struct pgv *pg_vec,
578                         union tpacket_req_u *req_u)
579 {
580         struct tpacket_kbdq_core *p1 = GET_PBDQC_FROM_RB(rb);
581         struct tpacket_block_desc *pbd;
582 
583         memset(p1, 0x0, sizeof(*p1));
584 
585         p1->knxt_seq_num = 1;
586         p1->pkbdq = pg_vec;
587         pbd = (struct tpacket_block_desc *)pg_vec[0].buffer;
588         p1->pkblk_start = pg_vec[0].buffer;
589         p1->kblk_size = req_u->req3.tp_block_size;
590         p1->knum_blocks = req_u->req3.tp_block_nr;
591         p1->hdrlen = po->tp_hdrlen;
592         p1->version = po->tp_version;
593         p1->last_kactive_blk_num = 0;
594         po->stats.stats3.tp_freeze_q_cnt = 0;
595         if (req_u->req3.tp_retire_blk_tov)
596                 p1->retire_blk_tov = req_u->req3.tp_retire_blk_tov;
597         else
598                 p1->retire_blk_tov = prb_calc_retire_blk_tmo(po,
599                                                 req_u->req3.tp_block_size);
600         p1->tov_in_jiffies = msecs_to_jiffies(p1->retire_blk_tov);
601         p1->blk_sizeof_priv = req_u->req3.tp_sizeof_priv;
602 
603         p1->max_frame_len = p1->kblk_size - BLK_PLUS_PRIV(p1->blk_sizeof_priv);
604         prb_init_ft_ops(p1, req_u);
605         prb_setup_retire_blk_timer(po);
606         prb_open_block(p1, pbd);
607 }
608 
609 /*  Do NOT update the last_blk_num first.
610  *  Assumes sk_buff_head lock is held.
611  */
612 static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc)
613 {
614         mod_timer(&pkc->retire_blk_timer,
615                         jiffies + pkc->tov_in_jiffies);
616         pkc->last_kactive_blk_num = pkc->kactive_blk_num;
617 }
618 
619 /*
620  * Timer logic:
621  * 1) We refresh the timer only when we open a block.
622  *    By doing this we don't waste cycles refreshing the timer
623  *        on packet-by-packet basis.
624  *
625  * With a 1MB block-size, on a 1Gbps line, it will take
626  * i) ~8 ms to fill a block + ii) memcpy etc.
627  * In this cut we are not accounting for the memcpy time.
628  *
629  * So, if the user sets the 'tmo' to 10ms then the timer
630  * will never fire while the block is still getting filled
631  * (which is what we want). However, the user could choose
632  * to close a block early and that's fine.
633  *
634  * But when the timer does fire, we check whether or not to refresh it.
635  * Since the tmo granularity is in msecs, it is not too expensive
636  * to refresh the timer, lets say every '8' msecs.
637  * Either the user can set the 'tmo' or we can derive it based on
638  * a) line-speed and b) block-size.
639  * prb_calc_retire_blk_tmo() calculates the tmo.
640  *
641  */
642 static void prb_retire_rx_blk_timer_expired(struct timer_list *t)
643 {
644         struct packet_sock *po =
645                 from_timer(po, t, rx_ring.prb_bdqc.retire_blk_timer);
646         struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
647         unsigned int frozen;
648         struct tpacket_block_desc *pbd;
649 
650         spin_lock(&po->sk.sk_receive_queue.lock);
651 
652         frozen = prb_queue_frozen(pkc);
653         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
654 
655         if (unlikely(pkc->delete_blk_timer))
656                 goto out;
657 
658         /* We only need to plug the race when the block is partially filled.
659          * tpacket_rcv:
660          *              lock(); increment BLOCK_NUM_PKTS; unlock()
661          *              copy_bits() is in progress ...
662          *              timer fires on other cpu:
663          *              we can't retire the current block because copy_bits
664          *              is in progress.
665          *
666          */
667         if (BLOCK_NUM_PKTS(pbd)) {
668                 while (atomic_read(&pkc->blk_fill_in_prog)) {
669                         /* Waiting for skb_copy_bits to finish... */
670                         cpu_relax();
671                 }
672         }
673 
674         if (pkc->last_kactive_blk_num == pkc->kactive_blk_num) {
675                 if (!frozen) {
676                         if (!BLOCK_NUM_PKTS(pbd)) {
677                                 /* An empty block. Just refresh the timer. */
678                                 goto refresh_timer;
679                         }
680                         prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO);
681                         if (!prb_dispatch_next_block(pkc, po))
682                                 goto refresh_timer;
683                         else
684                                 goto out;
685                 } else {
686                         /* Case 1. Queue was frozen because user-space was
687                          *         lagging behind.
688                          */
689                         if (prb_curr_blk_in_use(pbd)) {
690                                 /*
691                                  * Ok, user-space is still behind.
692                                  * So just refresh the timer.
693                                  */
694                                 goto refresh_timer;
695                         } else {
696                                /* Case 2. queue was frozen,user-space caught up,
697                                 * now the link went idle && the timer fired.
698                                 * We don't have a block to close.So we open this
699                                 * block and restart the timer.
700                                 * opening a block thaws the queue,restarts timer
701                                 * Thawing/timer-refresh is a side effect.
702                                 */
703                                 prb_open_block(pkc, pbd);
704                                 goto out;
705                         }
706                 }
707         }
708 
709 refresh_timer:
710         _prb_refresh_rx_retire_blk_timer(pkc);
711 
712 out:
713         spin_unlock(&po->sk.sk_receive_queue.lock);
714 }
715 
716 static void prb_flush_block(struct tpacket_kbdq_core *pkc1,
717                 struct tpacket_block_desc *pbd1, __u32 status)
718 {
719         /* Flush everything minus the block header */
720 
721 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
722         u8 *start, *end;
723 
724         start = (u8 *)pbd1;
725 
726         /* Skip the block header(we know header WILL fit in 4K) */
727         start += PAGE_SIZE;
728 
729         end = (u8 *)PAGE_ALIGN((unsigned long)pkc1->pkblk_end);
730         for (; start < end; start += PAGE_SIZE)
731                 flush_dcache_page(pgv_to_page(start));
732 
733         smp_wmb();
734 #endif
735 
736         /* Now update the block status. */
737 
738         BLOCK_STATUS(pbd1) = status;
739 
740         /* Flush the block header */
741 
742 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
743         start = (u8 *)pbd1;
744         flush_dcache_page(pgv_to_page(start));
745 
746         smp_wmb();
747 #endif
748 }
749 
750 /*
751  * Side effect:
752  *
753  * 1) flush the block
754  * 2) Increment active_blk_num
755  *
756  * Note:We DONT refresh the timer on purpose.
757  *      Because almost always the next block will be opened.
758  */
759 static void prb_close_block(struct tpacket_kbdq_core *pkc1,
760                 struct tpacket_block_desc *pbd1,
761                 struct packet_sock *po, unsigned int stat)
762 {
763         __u32 status = TP_STATUS_USER | stat;
764 
765         struct tpacket3_hdr *last_pkt;
766         struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
767         struct sock *sk = &po->sk;
768 
769         if (po->stats.stats3.tp_drops)
770                 status |= TP_STATUS_LOSING;
771 
772         last_pkt = (struct tpacket3_hdr *)pkc1->prev;
773         last_pkt->tp_next_offset = 0;
774 
775         /* Get the ts of the last pkt */
776         if (BLOCK_NUM_PKTS(pbd1)) {
777                 h1->ts_last_pkt.ts_sec = last_pkt->tp_sec;
778                 h1->ts_last_pkt.ts_nsec = last_pkt->tp_nsec;
779         } else {
780                 /* Ok, we tmo'd - so get the current time.
781                  *
782                  * It shouldn't really happen as we don't close empty
783                  * blocks. See prb_retire_rx_blk_timer_expired().
784                  */
785                 struct timespec ts;
786                 getnstimeofday(&ts);
787                 h1->ts_last_pkt.ts_sec = ts.tv_sec;
788                 h1->ts_last_pkt.ts_nsec = ts.tv_nsec;
789         }
790 
791         smp_wmb();
792 
793         /* Flush the block */
794         prb_flush_block(pkc1, pbd1, status);
795 
796         sk->sk_data_ready(sk);
797 
798         pkc1->kactive_blk_num = GET_NEXT_PRB_BLK_NUM(pkc1);
799 }
800 
801 static void prb_thaw_queue(struct tpacket_kbdq_core *pkc)
802 {
803         pkc->reset_pending_on_curr_blk = 0;
804 }
805 
806 /*
807  * Side effect of opening a block:
808  *
809  * 1) prb_queue is thawed.
810  * 2) retire_blk_timer is refreshed.
811  *
812  */
813 static void prb_open_block(struct tpacket_kbdq_core *pkc1,
814         struct tpacket_block_desc *pbd1)
815 {
816         struct timespec ts;
817         struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
818 
819         smp_rmb();
820 
821         /* We could have just memset this but we will lose the
822          * flexibility of making the priv area sticky
823          */
824 
825         BLOCK_SNUM(pbd1) = pkc1->knxt_seq_num++;
826         BLOCK_NUM_PKTS(pbd1) = 0;
827         BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
828 
829         getnstimeofday(&ts);
830 
831         h1->ts_first_pkt.ts_sec = ts.tv_sec;
832         h1->ts_first_pkt.ts_nsec = ts.tv_nsec;
833 
834         pkc1->pkblk_start = (char *)pbd1;
835         pkc1->nxt_offset = pkc1->pkblk_start + BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
836 
837         BLOCK_O2FP(pbd1) = (__u32)BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
838         BLOCK_O2PRIV(pbd1) = BLK_HDR_LEN;
839 
840         pbd1->version = pkc1->version;
841         pkc1->prev = pkc1->nxt_offset;
842         pkc1->pkblk_end = pkc1->pkblk_start + pkc1->kblk_size;
843 
844         prb_thaw_queue(pkc1);
845         _prb_refresh_rx_retire_blk_timer(pkc1);
846 
847         smp_wmb();
848 }
849 
850 /*
851  * Queue freeze logic:
852  * 1) Assume tp_block_nr = 8 blocks.
853  * 2) At time 't0', user opens Rx ring.
854  * 3) Some time past 't0', kernel starts filling blocks starting from 0 .. 7
855  * 4) user-space is either sleeping or processing block ''.
856  * 5) tpacket_rcv is currently filling block '7', since there is no space left,
857  *    it will close block-7,loop around and try to fill block ''.
858  *    call-flow:
859  *    __packet_lookup_frame_in_block
860  *      prb_retire_current_block()
861  *      prb_dispatch_next_block()
862  *        |->(BLOCK_STATUS == USER) evaluates to true
863  *    5.1) Since block-0 is currently in-use, we just freeze the queue.
864  * 6) Now there are two cases:
865  *    6.1) Link goes idle right after the queue is frozen.
866  *         But remember, the last open_block() refreshed the timer.
867  *         When this timer expires,it will refresh itself so that we can
868  *         re-open block-0 in near future.
869  *    6.2) Link is busy and keeps on receiving packets. This is a simple
870  *         case and __packet_lookup_frame_in_block will check if block-0
871  *         is free and can now be re-used.
872  */
873 static void prb_freeze_queue(struct tpacket_kbdq_core *pkc,
874                                   struct packet_sock *po)
875 {
876         pkc->reset_pending_on_curr_blk = 1;
877         po->stats.stats3.tp_freeze_q_cnt++;
878 }
879 
880 #define TOTAL_PKT_LEN_INCL_ALIGN(length) (ALIGN((length), V3_ALIGNMENT))
881 
882 /*
883  * If the next block is free then we will dispatch it
884  * and return a good offset.
885  * Else, we will freeze the queue.
886  * So, caller must check the return value.
887  */
888 static void *prb_dispatch_next_block(struct tpacket_kbdq_core *pkc,
889                 struct packet_sock *po)
890 {
891         struct tpacket_block_desc *pbd;
892 
893         smp_rmb();
894 
895         /* 1. Get current block num */
896         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
897 
898         /* 2. If this block is currently in_use then freeze the queue */
899         if (TP_STATUS_USER & BLOCK_STATUS(pbd)) {
900                 prb_freeze_queue(pkc, po);
901                 return NULL;
902         }
903 
904         /*
905          * 3.
906          * open this block and return the offset where the first packet
907          * needs to get stored.
908          */
909         prb_open_block(pkc, pbd);
910         return (void *)pkc->nxt_offset;
911 }
912 
913 static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
914                 struct packet_sock *po, unsigned int status)
915 {
916         struct tpacket_block_desc *pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
917 
918         /* retire/close the current block */
919         if (likely(TP_STATUS_KERNEL == BLOCK_STATUS(pbd))) {
920                 /*
921                  * Plug the case where copy_bits() is in progress on
922                  * cpu-0 and tpacket_rcv() got invoked on cpu-1, didn't
923                  * have space to copy the pkt in the current block and
924                  * called prb_retire_current_block()
925                  *
926                  * We don't need to worry about the TMO case because
927                  * the timer-handler already handled this case.
928                  */
929                 if (!(status & TP_STATUS_BLK_TMO)) {
930                         while (atomic_read(&pkc->blk_fill_in_prog)) {
931                                 /* Waiting for skb_copy_bits to finish... */
932                                 cpu_relax();
933                         }
934                 }
935                 prb_close_block(pkc, pbd, po, status);
936                 return;
937         }
938 }
939 
940 static int prb_curr_blk_in_use(struct tpacket_block_desc *pbd)
941 {
942         return TP_STATUS_USER & BLOCK_STATUS(pbd);
943 }
944 
945 static int prb_queue_frozen(struct tpacket_kbdq_core *pkc)
946 {
947         return pkc->reset_pending_on_curr_blk;
948 }
949 
950 static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
951 {
952         struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
953         atomic_dec(&pkc->blk_fill_in_prog);
954 }
955 
956 static void prb_fill_rxhash(struct tpacket_kbdq_core *pkc,
957                         struct tpacket3_hdr *ppd)
958 {
959         ppd->hv1.tp_rxhash = skb_get_hash(pkc->skb);
960 }
961 
962 static void prb_clear_rxhash(struct tpacket_kbdq_core *pkc,
963                         struct tpacket3_hdr *ppd)
964 {
965         ppd->hv1.tp_rxhash = 0;
966 }
967 
968 static void prb_fill_vlan_info(struct tpacket_kbdq_core *pkc,
969                         struct tpacket3_hdr *ppd)
970 {
971         if (skb_vlan_tag_present(pkc->skb)) {
972                 ppd->hv1.tp_vlan_tci = skb_vlan_tag_get(pkc->skb);
973                 ppd->hv1.tp_vlan_tpid = ntohs(pkc->skb->vlan_proto);
974                 ppd->tp_status = TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
975         } else {
976                 ppd->hv1.tp_vlan_tci = 0;
977                 ppd->hv1.tp_vlan_tpid = 0;
978                 ppd->tp_status = TP_STATUS_AVAILABLE;
979         }
980 }
981 
982 static void prb_run_all_ft_ops(struct tpacket_kbdq_core *pkc,
983                         struct tpacket3_hdr *ppd)
984 {
985         ppd->hv1.tp_padding = 0;
986         prb_fill_vlan_info(pkc, ppd);
987 
988         if (pkc->feature_req_word & TP_FT_REQ_FILL_RXHASH)
989                 prb_fill_rxhash(pkc, ppd);
990         else
991                 prb_clear_rxhash(pkc, ppd);
992 }
993 
994 static void prb_fill_curr_block(char *curr,
995                                 struct tpacket_kbdq_core *pkc,
996                                 struct tpacket_block_desc *pbd,
997                                 unsigned int len)
998 {
999         struct tpacket3_hdr *ppd;
1000 
1001         ppd  = (struct tpacket3_hdr *)curr;
1002         ppd->tp_next_offset = TOTAL_PKT_LEN_INCL_ALIGN(len);
1003         pkc->prev = curr;
1004         pkc->nxt_offset += TOTAL_PKT_LEN_INCL_ALIGN(len);
1005         BLOCK_LEN(pbd) += TOTAL_PKT_LEN_INCL_ALIGN(len);
1006         BLOCK_NUM_PKTS(pbd) += 1;
1007         atomic_inc(&pkc->blk_fill_in_prog);
1008         prb_run_all_ft_ops(pkc, ppd);
1009 }
1010 
1011 /* Assumes caller has the sk->rx_queue.lock */
1012 static void *__packet_lookup_frame_in_block(struct packet_sock *po,
1013                                             struct sk_buff *skb,
1014                                                 int status,
1015                                             unsigned int len
1016                                             )
1017 {
1018         struct tpacket_kbdq_core *pkc;
1019         struct tpacket_block_desc *pbd;
1020         char *curr, *end;
1021 
1022         pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
1023         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
1024 
1025         /* Queue is frozen when user space is lagging behind */
1026         if (prb_queue_frozen(pkc)) {
1027                 /*
1028                  * Check if that last block which caused the queue to freeze,
1029                  * is still in_use by user-space.
1030                  */
1031                 if (prb_curr_blk_in_use(pbd)) {
1032                         /* Can't record this packet */
1033                         return NULL;
1034                 } else {
1035                         /*
1036                          * Ok, the block was released by user-space.
1037                          * Now let's open that block.
1038                          * opening a block also thaws the queue.
1039                          * Thawing is a side effect.
1040                          */
1041                         prb_open_block(pkc, pbd);
1042                 }
1043         }
1044 
1045         smp_mb();
1046         curr = pkc->nxt_offset;
1047         pkc->skb = skb;
1048         end = (char *)pbd + pkc->kblk_size;
1049 
1050         /* first try the current block */
1051         if (curr+TOTAL_PKT_LEN_INCL_ALIGN(len) < end) {
1052                 prb_fill_curr_block(curr, pkc, pbd, len);
1053                 return (void *)curr;
1054         }
1055 
1056         /* Ok, close the current block */
1057         prb_retire_current_block(pkc, po, 0);
1058 
1059         /* Now, try to dispatch the next block */
1060         curr = (char *)prb_dispatch_next_block(pkc, po);
1061         if (curr) {
1062                 pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
1063                 prb_fill_curr_block(curr, pkc, pbd, len);
1064                 return (void *)curr;
1065         }
1066 
1067         /*
1068          * No free blocks are available.user_space hasn't caught up yet.
1069          * Queue was just frozen and now this packet will get dropped.
1070          */
1071         return NULL;
1072 }
1073 
1074 static void *packet_current_rx_frame(struct packet_sock *po,
1075                                             struct sk_buff *skb,
1076                                             int status, unsigned int len)
1077 {
1078         char *curr = NULL;
1079         switch (po->tp_version) {
1080         case TPACKET_V1:
1081         case TPACKET_V2:
1082                 curr = packet_lookup_frame(po, &po->rx_ring,
1083                                         po->rx_ring.head, status);
1084                 return curr;
1085         case TPACKET_V3:
1086                 return __packet_lookup_frame_in_block(po, skb, status, len);
1087         default:
1088                 WARN(1, "TPACKET version not supported\n");
1089                 BUG();
1090                 return NULL;
1091         }
1092 }
1093 
1094 static void *prb_lookup_block(struct packet_sock *po,
1095                                      struct packet_ring_buffer *rb,
1096                                      unsigned int idx,
1097                                      int status)
1098 {
1099         struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
1100         struct tpacket_block_desc *pbd = GET_PBLOCK_DESC(pkc, idx);
1101 
1102         if (status != BLOCK_STATUS(pbd))
1103                 return NULL;
1104         return pbd;
1105 }
1106 
1107 static int prb_previous_blk_num(struct packet_ring_buffer *rb)
1108 {
1109         unsigned int prev;
1110         if (rb->prb_bdqc.kactive_blk_num)
1111                 prev = rb->prb_bdqc.kactive_blk_num-1;
1112         else
1113                 prev = rb->prb_bdqc.knum_blocks-1;
1114         return prev;
1115 }
1116 
1117 /* Assumes caller has held the rx_queue.lock */
1118 static void *__prb_previous_block(struct packet_sock *po,
1119                                          struct packet_ring_buffer *rb,
1120                                          int status)
1121 {
1122         unsigned int previous = prb_previous_blk_num(rb);
1123         return prb_lookup_block(po, rb, previous, status);
1124 }
1125 
1126 static void *packet_previous_rx_frame(struct packet_sock *po,
1127                                              struct packet_ring_buffer *rb,
1128                                              int status)
1129 {
1130         if (po->tp_version <= TPACKET_V2)
1131                 return packet_previous_frame(po, rb, status);
1132 
1133         return __prb_previous_block(po, rb, status);
1134 }
1135 
1136 static void packet_increment_rx_head(struct packet_sock *po,
1137                                             struct packet_ring_buffer *rb)
1138 {
1139         switch (po->tp_version) {
1140         case TPACKET_V1:
1141         case TPACKET_V2:
1142                 return packet_increment_head(rb);
1143         case TPACKET_V3:
1144         default:
1145                 WARN(1, "TPACKET version not supported.\n");
1146                 BUG();
1147                 return;
1148         }
1149 }
1150 
1151 static void *packet_previous_frame(struct packet_sock *po,
1152                 struct packet_ring_buffer *rb,
1153                 int status)
1154 {
1155         unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
1156         return packet_lookup_frame(po, rb, previous, status);
1157 }
1158 
1159 static void packet_increment_head(struct packet_ring_buffer *buff)
1160 {
1161         buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
1162 }
1163 
1164 static void packet_inc_pending(struct packet_ring_buffer *rb)
1165 {
1166         this_cpu_inc(*rb->pending_refcnt);
1167 }
1168 
1169 static void packet_dec_pending(struct packet_ring_buffer *rb)
1170 {
1171         this_cpu_dec(*rb->pending_refcnt);
1172 }
1173 
1174 static unsigned int packet_read_pending(const struct packet_ring_buffer *rb)
1175 {
1176         unsigned int refcnt = 0;
1177         int cpu;
1178 
1179         /* We don't use pending refcount in rx_ring. */
1180         if (rb->pending_refcnt == NULL)
1181                 return 0;
1182 
1183         for_each_possible_cpu(cpu)
1184                 refcnt += *per_cpu_ptr(rb->pending_refcnt, cpu);
1185 
1186         return refcnt;
1187 }
1188 
1189 static int packet_alloc_pending(struct packet_sock *po)
1190 {
1191         po->rx_ring.pending_refcnt = NULL;
1192 
1193         po->tx_ring.pending_refcnt = alloc_percpu(unsigned int);
1194         if (unlikely(po->tx_ring.pending_refcnt == NULL))
1195                 return -ENOBUFS;
1196 
1197         return 0;
1198 }
1199 
1200 static void packet_free_pending(struct packet_sock *po)
1201 {
1202         free_percpu(po->tx_ring.pending_refcnt);
1203 }
1204 
1205 #define ROOM_POW_OFF    2
1206 #define ROOM_NONE       0x0
1207 #define ROOM_LOW        0x1
1208 #define ROOM_NORMAL     0x2
1209 
1210 static bool __tpacket_has_room(struct packet_sock *po, int pow_off)
1211 {
1212         int idx, len;
1213 
1214         len = po->rx_ring.frame_max + 1;
1215         idx = po->rx_ring.head;
1216         if (pow_off)
1217                 idx += len >> pow_off;
1218         if (idx >= len)
1219                 idx -= len;
1220         return packet_lookup_frame(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
1221 }
1222 
1223 static bool __tpacket_v3_has_room(struct packet_sock *po, int pow_off)
1224 {
1225         int idx, len;
1226 
1227         len = po->rx_ring.prb_bdqc.knum_blocks;
1228         idx = po->rx_ring.prb_bdqc.kactive_blk_num;
1229         if (pow_off)
1230                 idx += len >> pow_off;
1231         if (idx >= len)
1232                 idx -= len;
1233         return prb_lookup_block(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
1234 }
1235 
1236 static int __packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
1237 {
1238         struct sock *sk = &po->sk;
1239         int ret = ROOM_NONE;
1240 
1241         if (po->prot_hook.func != tpacket_rcv) {
1242                 int avail = sk->sk_rcvbuf - atomic_read(&sk->sk_rmem_alloc)
1243                                           - (skb ? skb->truesize : 0);
1244                 if (avail > (sk->sk_rcvbuf >> ROOM_POW_OFF))
1245                         return ROOM_NORMAL;
1246                 else if (avail > 0)
1247                         return ROOM_LOW;
1248                 else
1249                         return ROOM_NONE;
1250         }
1251 
1252         if (po->tp_version == TPACKET_V3) {
1253                 if (__tpacket_v3_has_room(po, ROOM_POW_OFF))
1254                         ret = ROOM_NORMAL;
1255                 else if (__tpacket_v3_has_room(po, 0))
1256                         ret = ROOM_LOW;
1257         } else {
1258                 if (__tpacket_has_room(po, ROOM_POW_OFF))
1259                         ret = ROOM_NORMAL;
1260                 else if (__tpacket_has_room(po, 0))
1261                         ret = ROOM_LOW;
1262         }
1263 
1264         return ret;
1265 }
1266 
1267 static int packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
1268 {
1269         int ret;
1270         bool has_room;
1271 
1272         spin_lock_bh(&po->sk.sk_receive_queue.lock);
1273         ret = __packet_rcv_has_room(po, skb);
1274         has_room = ret == ROOM_NORMAL;
1275         if (po->pressure == has_room)
1276                 po->pressure = !has_room;
1277         spin_unlock_bh(&po->sk.sk_receive_queue.lock);
1278 
1279         return ret;
1280 }
1281 
1282 static void packet_sock_destruct(struct sock *sk)
1283 {
1284         skb_queue_purge(&sk->sk_error_queue);
1285 
1286         WARN_ON(atomic_read(&sk->sk_rmem_alloc));
1287         WARN_ON(refcount_read(&sk->sk_wmem_alloc));
1288 
1289         if (!sock_flag(sk, SOCK_DEAD)) {
1290                 pr_err("Attempt to release alive packet socket: %p\n", sk);
1291                 return;
1292         }
1293 
1294         sk_refcnt_debug_dec(sk);
1295 }
1296 
1297 static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
1298 {
1299         u32 rxhash;
1300         int i, count = 0;
1301 
1302         rxhash = skb_get_hash(skb);
1303         for (i = 0; i < ROLLOVER_HLEN; i++)
1304                 if (po->rollover->history[i] == rxhash)
1305                         count++;
1306 
1307         po->rollover->history[prandom_u32() % ROLLOVER_HLEN] = rxhash;
1308         return count > (ROLLOVER_HLEN >> 1);
1309 }
1310 
1311 static unsigned int fanout_demux_hash(struct packet_fanout *f,
1312                                       struct sk_buff *skb,
1313                                       unsigned int num)
1314 {
1315         return reciprocal_scale(__skb_get_hash_symmetric(skb), num);
1316 }
1317 
1318 static unsigned int fanout_demux_lb(struct packet_fanout *f,
1319                                     struct sk_buff *skb,
1320                                     unsigned int num)
1321 {
1322         unsigned int val = atomic_inc_return(&f->rr_cur);
1323 
1324         return val % num;
1325 }
1326 
1327 static unsigned int fanout_demux_cpu(struct packet_fanout *f,
1328                                      struct sk_buff *skb,
1329                                      unsigned int num)
1330 {
1331         return smp_processor_id() % num;
1332 }
1333 
1334 static unsigned int fanout_demux_rnd(struct packet_fanout *f,
1335                                      struct sk_buff *skb,
1336                                      unsigned int num)
1337 {
1338         return prandom_u32_max(num);
1339 }
1340 
1341 static unsigned int fanout_demux_rollover(struct packet_fanout *f,
1342                                           struct sk_buff *skb,
1343                                           unsigned int idx, bool try_self,
1344                                           unsigned int num)
1345 {
1346         struct packet_sock *po, *po_next, *po_skip = NULL;
1347         unsigned int i, j, room = ROOM_NONE;
1348 
1349         po = pkt_sk(f->arr[idx]);
1350 
1351         if (try_self) {
1352                 room = packet_rcv_has_room(po, skb);
1353                 if (room == ROOM_NORMAL ||
1354                     (room == ROOM_LOW && !fanout_flow_is_huge(po, skb)))
1355                         return idx;
1356                 po_skip = po;
1357         }
1358 
1359         i = j = min_t(int, po->rollover->sock, num - 1);
1360         do {
1361                 po_next = pkt_sk(f->arr[i]);
1362                 if (po_next != po_skip && !po_next->pressure &&
1363                     packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) {
1364                         if (i != j)
1365                                 po->rollover->sock = i;
1366                         atomic_long_inc(&po->rollover->num);
1367                         if (room == ROOM_LOW)
1368                                 atomic_long_inc(&po->rollover->num_huge);
1369                         return i;
1370                 }
1371 
1372                 if (++i == num)
1373                         i = 0;
1374         } while (i != j);
1375 
1376         atomic_long_inc(&po->rollover->num_failed);
1377         return idx;
1378 }
1379 
1380 static unsigned int fanout_demux_qm(struct packet_fanout *f,
1381                                     struct sk_buff *skb,
1382                                     unsigned int num)
1383 {
1384         return skb_get_queue_mapping(skb) % num;
1385 }
1386 
1387 static unsigned int fanout_demux_bpf(struct packet_fanout *f,
1388                                      struct sk_buff *skb,
1389                                      unsigned int num)
1390 {
1391         struct bpf_prog *prog;
1392         unsigned int ret = 0;
1393 
1394         rcu_read_lock();
1395         prog = rcu_dereference(f->bpf_prog);
1396         if (prog)
1397                 ret = bpf_prog_run_clear_cb(prog, skb) % num;
1398         rcu_read_unlock();
1399 
1400         return ret;
1401 }
1402 
1403 static bool fanout_has_flag(struct packet_fanout *f, u16 flag)
1404 {
1405         return f->flags & (flag >> 8);
1406 }
1407 
1408 static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
1409                              struct packet_type *pt, struct net_device *orig_dev)
1410 {
1411         struct packet_fanout *f = pt->af_packet_priv;
1412         unsigned int num = READ_ONCE(f->num_members);
1413         struct net *net = read_pnet(&f->net);
1414         struct packet_sock *po;
1415         unsigned int idx;
1416 
1417         if (!net_eq(dev_net(dev), net) || !num) {
1418                 kfree_skb(skb);
1419                 return 0;
1420         }
1421 
1422         if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
1423                 skb = ip_check_defrag(net, skb, IP_DEFRAG_AF_PACKET);
1424                 if (!skb)
1425                         return 0;
1426         }
1427         switch (f->type) {
1428         case PACKET_FANOUT_HASH:
1429         default:
1430                 idx = fanout_demux_hash(f, skb, num);
1431                 break;
1432         case PACKET_FANOUT_LB:
1433                 idx = fanout_demux_lb(f, skb, num);
1434                 break;
1435         case PACKET_FANOUT_CPU:
1436                 idx = fanout_demux_cpu(f, skb, num);
1437                 break;
1438         case PACKET_FANOUT_RND:
1439                 idx = fanout_demux_rnd(f, skb, num);
1440                 break;
1441         case PACKET_FANOUT_QM:
1442                 idx = fanout_demux_qm(f, skb, num);
1443                 break;
1444         case PACKET_FANOUT_ROLLOVER:
1445                 idx = fanout_demux_rollover(f, skb, 0, false, num);
1446                 break;
1447         case PACKET_FANOUT_CBPF:
1448         case PACKET_FANOUT_EBPF:
1449                 idx = fanout_demux_bpf(f, skb, num);
1450                 break;
1451         }
1452 
1453         if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER))
1454                 idx = fanout_demux_rollover(f, skb, idx, true, num);
1455 
1456         po = pkt_sk(f->arr[idx]);
1457         return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
1458 }
1459 
1460 DEFINE_MUTEX(fanout_mutex);
1461 EXPORT_SYMBOL_GPL(fanout_mutex);
1462 static LIST_HEAD(fanout_list);
1463 static u16 fanout_next_id;
1464 
1465 static void __fanout_link(struct sock *sk, struct packet_sock *po)
1466 {
1467         struct packet_fanout *f = po->fanout;
1468 
1469         spin_lock(&f->lock);
1470         f->arr[f->num_members] = sk;
1471         smp_wmb();
1472         f->num_members++;
1473         if (f->num_members == 1)
1474                 dev_add_pack(&f->prot_hook);
1475         spin_unlock(&f->lock);
1476 }
1477 
1478 static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
1479 {
1480         struct packet_fanout *f = po->fanout;
1481         int i;
1482 
1483         spin_lock(&f->lock);
1484         for (i = 0; i < f->num_members; i++) {
1485                 if (f->arr[i] == sk)
1486                         break;
1487         }
1488         BUG_ON(i >= f->num_members);
1489         f->arr[i] = f->arr[f->num_members - 1];
1490         f->num_members--;
1491         if (f->num_members == 0)
1492                 __dev_remove_pack(&f->prot_hook);
1493         spin_unlock(&f->lock);
1494 }
1495 
1496 static bool match_fanout_group(struct packet_type *ptype, struct sock *sk)
1497 {
1498         if (sk->sk_family != PF_PACKET)
1499                 return false;
1500 
1501         return ptype->af_packet_priv == pkt_sk(sk)->fanout;
1502 }
1503 
1504 static void fanout_init_data(struct packet_fanout *f)
1505 {
1506         switch (f->type) {
1507         case PACKET_FANOUT_LB:
1508                 atomic_set(&f->rr_cur, 0);
1509                 break;
1510         case PACKET_FANOUT_CBPF:
1511         case PACKET_FANOUT_EBPF:
1512                 RCU_INIT_POINTER(f->bpf_prog, NULL);
1513                 break;
1514         }
1515 }
1516 
1517 static void __fanout_set_data_bpf(struct packet_fanout *f, struct bpf_prog *new)
1518 {
1519         struct bpf_prog *old;
1520 
1521         spin_lock(&f->lock);
1522         old = rcu_dereference_protected(f->bpf_prog, lockdep_is_held(&f->lock));
1523         rcu_assign_pointer(f->bpf_prog, new);
1524         spin_unlock(&f->lock);
1525 
1526         if (old) {
1527                 synchronize_net();
1528                 bpf_prog_destroy(old);
1529         }
1530 }
1531 
1532 static int fanout_set_data_cbpf(struct packet_sock *po, char __user *data,
1533                                 unsigned int len)
1534 {
1535         struct bpf_prog *new;
1536         struct sock_fprog fprog;
1537         int ret;
1538 
1539         if (sock_flag(&po->sk, SOCK_FILTER_LOCKED))
1540                 return -EPERM;
1541         if (len != sizeof(fprog))
1542                 return -EINVAL;
1543         if (copy_from_user(&fprog, data, len))
1544                 return -EFAULT;
1545 
1546         ret = bpf_prog_create_from_user(&new, &fprog, NULL, false);
1547         if (ret)
1548                 return ret;
1549 
1550         __fanout_set_data_bpf(po->fanout, new);
1551         return 0;
1552 }
1553 
1554 static int fanout_set_data_ebpf(struct packet_sock *po, char __user *data,
1555                                 unsigned int len)
1556 {
1557         struct bpf_prog *new;
1558         u32 fd;
1559 
1560         if (sock_flag(&po->sk, SOCK_FILTER_LOCKED))
1561                 return -EPERM;
1562         if (len != sizeof(fd))
1563                 return -EINVAL;
1564         if (copy_from_user(&fd, data, len))
1565                 return -EFAULT;
1566 
1567         new = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
1568         if (IS_ERR(new))
1569                 return PTR_ERR(new);
1570 
1571         __fanout_set_data_bpf(po->fanout, new);
1572         return 0;
1573 }
1574 
1575 static int fanout_set_data(struct packet_sock *po, char __user *data,
1576                            unsigned int len)
1577 {
1578         switch (po->fanout->type) {
1579         case PACKET_FANOUT_CBPF:
1580                 return fanout_set_data_cbpf(po, data, len);
1581         case PACKET_FANOUT_EBPF:
1582                 return fanout_set_data_ebpf(po, data, len);
1583         default:
1584                 return -EINVAL;
1585         }
1586 }
1587 
1588 static void fanout_release_data(struct packet_fanout *f)
1589 {
1590         switch (f->type) {
1591         case PACKET_FANOUT_CBPF:
1592         case PACKET_FANOUT_EBPF:
1593                 __fanout_set_data_bpf(f, NULL);
1594         }
1595 }
1596 
1597 static bool __fanout_id_is_free(struct sock *sk, u16 candidate_id)
1598 {
1599         struct packet_fanout *f;
1600 
1601         list_for_each_entry(f, &fanout_list, list) {
1602                 if (f->id == candidate_id &&
1603                     read_pnet(&f->net) == sock_net(sk)) {
1604                         return false;
1605                 }
1606         }
1607         return true;
1608 }
1609 
1610 static bool fanout_find_new_id(struct sock *sk, u16 *new_id)
1611 {
1612         u16 id = fanout_next_id;
1613 
1614         do {
1615                 if (__fanout_id_is_free(sk, id)) {
1616                         *new_id = id;
1617                         fanout_next_id = id + 1;
1618                         return true;
1619                 }
1620 
1621                 id++;
1622         } while (id != fanout_next_id);
1623 
1624         return false;
1625 }
1626 
1627 static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
1628 {
1629         struct packet_rollover *rollover = NULL;
1630         struct packet_sock *po = pkt_sk(sk);
1631         struct packet_fanout *f, *match;
1632         u8 type = type_flags & 0xff;
1633         u8 flags = type_flags >> 8;
1634         int err;
1635 
1636         switch (type) {
1637         case PACKET_FANOUT_ROLLOVER:
1638                 if (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)
1639                         return -EINVAL;
1640         case PACKET_FANOUT_HASH:
1641         case PACKET_FANOUT_LB:
1642         case PACKET_FANOUT_CPU:
1643         case PACKET_FANOUT_RND:
1644         case PACKET_FANOUT_QM:
1645         case PACKET_FANOUT_CBPF:
1646         case PACKET_FANOUT_EBPF:
1647                 break;
1648         default:
1649                 return -EINVAL;
1650         }
1651 
1652         mutex_lock(&fanout_mutex);
1653 
1654         err = -EALREADY;
1655         if (po->fanout)
1656                 goto out;
1657 
1658         if (type == PACKET_FANOUT_ROLLOVER ||
1659             (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
1660                 err = -ENOMEM;
1661                 rollover = kzalloc(sizeof(*rollover), GFP_KERNEL);
1662                 if (!rollover)
1663                         goto out;
1664                 atomic_long_set(&rollover->num, 0);
1665                 atomic_long_set(&rollover->num_huge, 0);
1666                 atomic_long_set(&rollover->num_failed, 0);
1667         }
1668 
1669         if (type_flags & PACKET_FANOUT_FLAG_UNIQUEID) {
1670                 if (id != 0) {
1671                         err = -EINVAL;
1672                         goto out;
1673                 }
1674                 if (!fanout_find_new_id(sk, &id)) {
1675                         err = -ENOMEM;
1676                         goto out;
1677                 }
1678                 /* ephemeral flag for the first socket in the group: drop it */
1679                 flags &= ~(PACKET_FANOUT_FLAG_UNIQUEID >> 8);
1680         }
1681 
1682         match = NULL;
1683         list_for_each_entry(f, &fanout_list, list) {
1684                 if (f->id == id &&
1685                     read_pnet(&f->net) == sock_net(sk)) {
1686                         match = f;
1687                         break;
1688                 }
1689         }
1690         err = -EINVAL;
1691         if (match && match->flags != flags)
1692                 goto out;
1693         if (!match) {
1694                 err = -ENOMEM;
1695                 match = kzalloc(sizeof(*match), GFP_KERNEL);
1696                 if (!match)
1697                         goto out;
1698                 write_pnet(&match->net, sock_net(sk));
1699                 match->id = id;
1700                 match->type = type;
1701                 match->flags = flags;
1702                 INIT_LIST_HEAD(&match->list);
1703                 spin_lock_init(&match->lock);
1704                 refcount_set(&match->sk_ref, 0);
1705                 fanout_init_data(match);
1706                 match->prot_hook.type = po->prot_hook.type;
1707                 match->prot_hook.dev = po->prot_hook.dev;
1708                 match->prot_hook.func = packet_rcv_fanout;
1709                 match->prot_hook.af_packet_priv = match;
1710                 match->prot_hook.id_match = match_fanout_group;
1711                 list_add(&match->list, &fanout_list);
1712         }
1713         err = -EINVAL;
1714 
1715         spin_lock(&po->bind_lock);
1716         if (po->running &&
1717             match->type == type &&
1718             match->prot_hook.type == po->prot_hook.type &&
1719             match->prot_hook.dev == po->prot_hook.dev) {
1720                 err = -ENOSPC;
1721                 if (refcount_read(&match->sk_ref) < PACKET_FANOUT_MAX) {
1722                         __dev_remove_pack(&po->prot_hook);
1723                         po->fanout = match;
1724                         po->rollover = rollover;
1725                         rollover = NULL;
1726                         refcount_set(&match->sk_ref, refcount_read(&match->sk_ref) + 1);
1727                         __fanout_link(sk, po);
1728                         err = 0;
1729                 }
1730         }
1731         spin_unlock(&po->bind_lock);
1732 
1733         if (err && !refcount_read(&match->sk_ref)) {
1734                 list_del(&match->list);
1735                 kfree(match);
1736         }
1737 
1738 out:
1739         kfree(rollover);
1740         mutex_unlock(&fanout_mutex);
1741         return err;
1742 }
1743 
1744 /* If pkt_sk(sk)->fanout->sk_ref is zero, this function removes
1745  * pkt_sk(sk)->fanout from fanout_list and returns pkt_sk(sk)->fanout.
1746  * It is the responsibility of the caller to call fanout_release_data() and
1747  * free the returned packet_fanout (after synchronize_net())
1748  */
1749 static struct packet_fanout *fanout_release(struct sock *sk)
1750 {
1751         struct packet_sock *po = pkt_sk(sk);
1752         struct packet_fanout *f;
1753 
1754         mutex_lock(&fanout_mutex);
1755         f = po->fanout;
1756         if (f) {
1757                 po->fanout = NULL;
1758 
1759                 if (refcount_dec_and_test(&f->sk_ref))
1760                         list_del(&f->list);
1761                 else
1762                         f = NULL;
1763         }
1764         mutex_unlock(&fanout_mutex);
1765 
1766         return f;
1767 }
1768 
1769 static bool packet_extra_vlan_len_allowed(const struct net_device *dev,
1770                                           struct sk_buff *skb)
1771 {
1772         /* Earlier code assumed this would be a VLAN pkt, double-check
1773          * this now that we have the actual packet in hand. We can only
1774          * do this check on Ethernet devices.
1775          */
1776         if (unlikely(dev->type != ARPHRD_ETHER))
1777                 return false;
1778 
1779         skb_reset_mac_header(skb);
1780         return likely(eth_hdr(skb)->h_proto == htons(ETH_P_8021Q));
1781 }
1782 
1783 static const struct proto_ops packet_ops;
1784 
1785 static const struct proto_ops packet_ops_spkt;
1786 
1787 static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
1788                            struct packet_type *pt, struct net_device *orig_dev)
1789 {
1790         struct sock *sk;
1791         struct sockaddr_pkt *spkt;
1792 
1793         /*
1794          *      When we registered the protocol we saved the socket in the data
1795          *      field for just this event.
1796          */
1797 
1798         sk = pt->af_packet_priv;
1799 
1800         /*
1801          *      Yank back the headers [hope the device set this
1802          *      right or kerboom...]
1803          *
1804          *      Incoming packets have ll header pulled,
1805          *      push it back.
1806          *
1807          *      For outgoing ones skb->data == skb_mac_header(skb)
1808          *      so that this procedure is noop.
1809          */
1810 
1811         if (skb->pkt_type == PACKET_LOOPBACK)
1812                 goto out;
1813 
1814         if (!net_eq(dev_net(dev), sock_net(sk)))
1815                 goto out;
1816 
1817         skb = skb_share_check(skb, GFP_ATOMIC);
1818         if (skb == NULL)
1819                 goto oom;
1820 
1821         /* drop any routing info */
1822         skb_dst_drop(skb);
1823 
1824         /* drop conntrack reference */
1825         nf_reset(skb);
1826 
1827         spkt = &PACKET_SKB_CB(skb)->sa.pkt;
1828 
1829         skb_push(skb, skb->data - skb_mac_header(skb));
1830 
1831         /*
1832          *      The SOCK_PACKET socket receives _all_ frames.
1833          */
1834 
1835         spkt->spkt_family = dev->type;
1836         strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
1837         spkt->spkt_protocol = skb->protocol;
1838 
1839         /*
1840          *      Charge the memory to the socket. This is done specifically
1841          *      to prevent sockets using all the memory up.
1842          */
1843 
1844         if (sock_queue_rcv_skb(sk, skb) == 0)
1845                 return 0;
1846 
1847 out:
1848         kfree_skb(skb);
1849 oom:
1850         return 0;
1851 }
1852 
1853 
1854 /*
1855  *      Output a raw packet to a device layer. This bypasses all the other
1856  *      protocol layers and you must therefore supply it with a complete frame
1857  */
1858 
1859 static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg,
1860                                size_t len)
1861 {
1862         struct sock *sk = sock->sk;
1863         DECLARE_SOCKADDR(struct sockaddr_pkt *, saddr, msg->msg_name);
1864         struct sk_buff *skb = NULL;
1865         struct net_device *dev;
1866         struct sockcm_cookie sockc;
1867         __be16 proto = 0;
1868         int err;
1869         int extra_len = 0;
1870 
1871         /*
1872          *      Get and verify the address.
1873          */
1874 
1875         if (saddr) {
1876                 if (msg->msg_namelen < sizeof(struct sockaddr))
1877                         return -EINVAL;
1878                 if (msg->msg_namelen == sizeof(struct sockaddr_pkt))
1879                         proto = saddr->spkt_protocol;
1880         } else
1881                 return -ENOTCONN;       /* SOCK_PACKET must be sent giving an address */
1882 
1883         /*
1884          *      Find the device first to size check it
1885          */
1886 
1887         saddr->spkt_device[sizeof(saddr->spkt_device) - 1] = 0;
1888 retry:
1889         rcu_read_lock();
1890         dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
1891         err = -ENODEV;
1892         if (dev == NULL)
1893                 goto out_unlock;
1894 
1895         err = -ENETDOWN;
1896         if (!(dev->flags & IFF_UP))
1897                 goto out_unlock;
1898 
1899         /*
1900          * You may not queue a frame bigger than the mtu. This is the lowest level
1901          * raw protocol and you must do your own fragmentation at this level.
1902          */
1903 
1904         if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
1905                 if (!netif_supports_nofcs(dev)) {
1906                         err = -EPROTONOSUPPORT;
1907                         goto out_unlock;
1908                 }
1909                 extra_len = 4; /* We're doing our own CRC */
1910         }
1911 
1912         err = -EMSGSIZE;
1913         if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN + extra_len)
1914                 goto out_unlock;
1915 
1916         if (!skb) {
1917                 size_t reserved = LL_RESERVED_SPACE(dev);
1918                 int tlen = dev->needed_tailroom;
1919                 unsigned int hhlen = dev->header_ops ? dev->hard_header_len : 0;
1920 
1921                 rcu_read_unlock();
1922                 skb = sock_wmalloc(sk, len + reserved + tlen, 0, GFP_KERNEL);
1923                 if (skb == NULL)
1924                         return -ENOBUFS;
1925                 /* FIXME: Save some space for broken drivers that write a hard
1926                  * header at transmission time by themselves. PPP is the notable
1927                  * one here. This should really be fixed at the driver level.
1928                  */
1929                 skb_reserve(skb, reserved);
1930                 skb_reset_network_header(skb);
1931 
1932                 /* Try to align data part correctly */
1933                 if (hhlen) {
1934                         skb->data -= hhlen;
1935                         skb->tail -= hhlen;
1936                         if (len < hhlen)
1937                                 skb_reset_network_header(skb);
1938                 }
1939                 err = memcpy_from_msg(skb_put(skb, len), msg, len);
1940                 if (err)
1941                         goto out_free;
1942                 goto retry;
1943         }
1944 
1945         if (!dev_validate_header(dev, skb->data, len)) {
1946                 err = -EINVAL;
1947                 goto out_unlock;
1948         }
1949         if (len > (dev->mtu + dev->hard_header_len + extra_len) &&
1950             !packet_extra_vlan_len_allowed(dev, skb)) {
1951                 err = -EMSGSIZE;
1952                 goto out_unlock;
1953         }
1954 
1955         sockcm_init(&sockc, sk);
1956         if (msg->msg_controllen) {
1957                 err = sock_cmsg_send(sk, msg, &sockc);
1958                 if (unlikely(err))
1959                         goto out_unlock;
1960         }
1961 
1962         skb->protocol = proto;
1963         skb->dev = dev;
1964         skb->priority = sk->sk_priority;
1965         skb->mark = sk->sk_mark;
1966         skb->tstamp = sockc.transmit_time;
1967 
1968         sock_tx_timestamp(sk, sockc.tsflags, &skb_shinfo(skb)->tx_flags);
1969 
1970         if (unlikely(extra_len == 4))
1971                 skb->no_fcs = 1;
1972 
1973         skb_probe_transport_header(skb, 0);
1974 
1975         dev_queue_xmit(skb);
1976         rcu_read_unlock();
1977         return len;
1978 
1979 out_unlock:
1980         rcu_read_unlock();
1981 out_free:
1982         kfree_skb(skb);
1983         return err;
1984 }
1985 
1986 static unsigned int run_filter(struct sk_buff *skb,
1987                                const struct sock *sk,
1988                                unsigned int res)
1989 {
1990         struct sk_filter *filter;
1991 
1992         rcu_read_lock();
1993         filter = rcu_dereference(sk->sk_filter);
1994         if (filter != NULL)
1995                 res = bpf_prog_run_clear_cb(filter->prog, skb);
1996         rcu_read_unlock();
1997 
1998         return res;
1999 }
2000 
2001 static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb,
2002                            size_t *len)
2003 {
2004         struct virtio_net_hdr vnet_hdr;
2005 
2006         if (*len < sizeof(vnet_hdr))
2007                 return -EINVAL;
2008         *len -= sizeof(vnet_hdr);
2009 
2010         if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le(), true, 0))
2011                 return -EINVAL;
2012 
2013         return memcpy_to_msg(msg, (void *)&vnet_hdr, sizeof(vnet_hdr));
2014 }
2015 
2016 /*
2017  * This function makes lazy skb cloning in hope that most of packets
2018  * are discarded by BPF.
2019  *
2020  * Note tricky part: we DO mangle shared skb! skb->data, skb->len
2021  * and skb->cb are mangled. It works because (and until) packets
2022  * falling here are owned by current CPU. Output packets are cloned
2023  * by dev_queue_xmit_nit(), input packets are processed by net_bh
2024  * sequencially, so that if we return skb to original state on exit,
2025  * we will not harm anyone.
2026  */
2027 
2028 static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
2029                       struct packet_type *pt, struct net_device *orig_dev)
2030 {
2031         struct sock *sk;
2032         struct sockaddr_ll *sll;
2033         struct packet_sock *po;
2034         u8 *skb_head = skb->data;
2035         int skb_len = skb->len;
2036         unsigned int snaplen, res;
2037         bool is_drop_n_account = false;
2038 
2039         if (skb->pkt_type == PACKET_LOOPBACK)
2040                 goto drop;
2041 
2042         sk = pt->af_packet_priv;
2043         po = pkt_sk(sk);
2044 
2045         if (!net_eq(dev_net(dev), sock_net(sk)))
2046                 goto drop;
2047 
2048         skb->dev = dev;
2049 
2050         if (dev->header_ops) {
2051                 /* The device has an explicit notion of ll header,
2052                  * exported to higher levels.
2053                  *
2054                  * Otherwise, the device hides details of its frame
2055                  * structure, so that corresponding packet head is
2056                  * never delivered to user.
2057                  */
2058                 if (sk->sk_type != SOCK_DGRAM)
2059                         skb_push(skb, skb->data - skb_mac_header(skb));
2060                 else if (skb->pkt_type == PACKET_OUTGOING) {
2061                         /* Special case: outgoing packets have ll header at head */
2062                         skb_pull(skb, skb_network_offset(skb));
2063                 }
2064         }
2065 
2066         snaplen = skb->len;
2067 
2068         res = run_filter(skb, sk, snaplen);
2069         if (!res)
2070                 goto drop_n_restore;
2071         if (snaplen > res)
2072                 snaplen = res;
2073 
2074         if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2075                 goto drop_n_acct;
2076 
2077         if (skb_shared(skb)) {
2078                 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
2079                 if (nskb == NULL)
2080                         goto drop_n_acct;
2081 
2082                 if (skb_head != skb->data) {
2083                         skb->data = skb_head;
2084                         skb->len = skb_len;
2085                 }
2086                 consume_skb(skb);
2087                 skb = nskb;
2088         }
2089 
2090         sock_skb_cb_check_size(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8);
2091 
2092         sll = &PACKET_SKB_CB(skb)->sa.ll;
2093         sll->sll_hatype = dev->type;
2094         sll->sll_pkttype = skb->pkt_type;
2095         if (unlikely(po->origdev))
2096                 sll->sll_ifindex = orig_dev->ifindex;
2097         else
2098                 sll->sll_ifindex = dev->ifindex;
2099 
2100         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
2101 
2102         /* sll->sll_family and sll->sll_protocol are set in packet_recvmsg().
2103          * Use their space for storing the original skb length.
2104          */
2105         PACKET_SKB_CB(skb)->sa.origlen = skb->len;
2106 
2107         if (pskb_trim(skb, snaplen))
2108                 goto drop_n_acct;
2109 
2110         skb_set_owner_r(skb, sk);
2111         skb->dev = NULL;
2112         skb_dst_drop(skb);
2113 
2114         /* drop conntrack reference */
2115         nf_reset(skb);
2116 
2117         spin_lock(&sk->sk_receive_queue.lock);
2118         po->stats.stats1.tp_packets++;
2119         sock_skb_set_dropcount(sk, skb);
2120         __skb_queue_tail(&sk->sk_receive_queue, skb);
2121         spin_unlock(&sk->sk_receive_queue.lock);
2122         sk->sk_data_ready(sk);
2123         return 0;
2124 
2125 drop_n_acct:
2126         is_drop_n_account = true;
2127         spin_lock(&sk->sk_receive_queue.lock);
2128         po->stats.stats1.tp_drops++;
2129         atomic_inc(&sk->sk_drops);
2130         spin_unlock(&sk->sk_receive_queue.lock);
2131 
2132 drop_n_restore:
2133         if (skb_head != skb->data && skb_shared(skb)) {
2134                 skb->data = skb_head;
2135                 skb->len = skb_len;
2136         }
2137 drop:
2138         if (!is_drop_n_account)
2139                 consume_skb(skb);
2140         else
2141                 kfree_skb(skb);
2142         return 0;
2143 }
2144 
2145 static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
2146                        struct packet_type *pt, struct net_device *orig_dev)
2147 {
2148         struct sock *sk;
2149         struct packet_sock *po;
2150         struct sockaddr_ll *sll;
2151         union tpacket_uhdr h;
2152         u8 *skb_head = skb->data;
2153         int skb_len = skb->len;
2154         unsigned int snaplen, res;
2155         unsigned long status = TP_STATUS_USER;
2156         unsigned short macoff, netoff, hdrlen;
2157         struct sk_buff *copy_skb = NULL;
2158         struct timespec ts;
2159         __u32 ts_status;
2160         bool is_drop_n_account = false;
2161         bool do_vnet = false;
2162 
2163         /* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
2164          * We may add members to them until current aligned size without forcing
2165          * userspace to call getsockopt(..., PACKET_HDRLEN, ...).
2166          */
2167         BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h2)) != 32);
2168         BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h3)) != 48);
2169 
2170         if (skb->pkt_type == PACKET_LOOPBACK)
2171                 goto drop;
2172 
2173         sk = pt->af_packet_priv;
2174         po = pkt_sk(sk);
2175 
2176         if (!net_eq(dev_net(dev), sock_net(sk)))
2177                 goto drop;
2178 
2179         if (dev->header_ops) {
2180                 if (sk->sk_type != SOCK_DGRAM)
2181                         skb_push(skb, skb->data - skb_mac_header(skb));
2182                 else if (skb->pkt_type == PACKET_OUTGOING) {
2183                         /* Special case: outgoing packets have ll header at head */
2184                         skb_pull(skb, skb_network_offset(skb));
2185                 }
2186         }
2187 
2188         snaplen = skb->len;
2189 
2190         res = run_filter(skb, sk, snaplen);
2191         if (!res)
2192                 goto drop_n_restore;
2193 
2194         if (skb->ip_summed == CHECKSUM_PARTIAL)
2195                 status |= TP_STATUS_CSUMNOTREADY;
2196         else if (skb->pkt_type != PACKET_OUTGOING &&
2197                  (skb->ip_summed == CHECKSUM_COMPLETE ||
2198                   skb_csum_unnecessary(skb)))
2199                 status |= TP_STATUS_CSUM_VALID;
2200 
2201         if (snaplen > res)
2202                 snaplen = res;
2203 
2204         if (sk->sk_type == SOCK_DGRAM) {
2205                 macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
2206                                   po->tp_reserve;
2207         } else {
2208                 unsigned int maclen = skb_network_offset(skb);
2209                 netoff = TPACKET_ALIGN(po->tp_hdrlen +
2210                                        (maclen < 16 ? 16 : maclen)) +
2211                                        po->tp_reserve;
2212                 if (po->has_vnet_hdr) {
2213                         netoff += sizeof(struct virtio_net_hdr);
2214                         do_vnet = true;
2215                 }
2216                 macoff = netoff - maclen;
2217         }
2218         if (po->tp_version <= TPACKET_V2) {
2219                 if (macoff + snaplen > po->rx_ring.frame_size) {
2220                         if (po->copy_thresh &&
2221                             atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
2222                                 if (skb_shared(skb)) {
2223                                         copy_skb = skb_clone(skb, GFP_ATOMIC);
2224                                 } else {
2225                                         copy_skb = skb_get(skb);
2226                                         skb_head = skb->data;
2227                                 }
2228                                 if (copy_skb)
2229                                         skb_set_owner_r(copy_skb, sk);
2230                         }
2231                         snaplen = po->rx_ring.frame_size - macoff;
2232                         if ((int)snaplen < 0) {
2233                                 snaplen = 0;
2234                                 do_vnet = false;
2235                         }
2236                 }
2237         } else if (unlikely(macoff + snaplen >
2238                             GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len)) {
2239                 u32 nval;
2240 
2241                 nval = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len - macoff;
2242                 pr_err_once("tpacket_rcv: packet too big, clamped from %u to %u. macoff=%u\n",
2243                             snaplen, nval, macoff);
2244                 snaplen = nval;
2245                 if (unlikely((int)snaplen < 0)) {
2246                         snaplen = 0;
2247                         macoff = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len;
2248                         do_vnet = false;
2249                 }
2250         }
2251         spin_lock(&sk->sk_receive_queue.lock);
2252         h.raw = packet_current_rx_frame(po, skb,
2253                                         TP_STATUS_KERNEL, (macoff+snaplen));
2254         if (!h.raw)
2255                 goto drop_n_account;
2256         if (po->tp_version <= TPACKET_V2) {
2257                 packet_increment_rx_head(po, &po->rx_ring);
2258         /*
2259          * LOSING will be reported till you read the stats,
2260          * because it's COR - Clear On Read.
2261          * Anyways, moving it for V1/V2 only as V3 doesn't need this
2262          * at packet level.
2263          */
2264                 if (po->stats.stats1.tp_drops)
2265                         status |= TP_STATUS_LOSING;
2266         }
2267 
2268         if (do_vnet &&
2269             virtio_net_hdr_from_skb(skb, h.raw + macoff -
2270                                     sizeof(struct virtio_net_hdr),
2271                                     vio_le(), true, 0))
2272                 goto drop_n_account;
2273 
2274         po->stats.stats1.tp_packets++;
2275         if (copy_skb) {
2276                 status |= TP_STATUS_COPY;
2277                 __skb_queue_tail(&sk->sk_receive_queue, copy_skb);
2278         }
2279         spin_unlock(&sk->sk_receive_queue.lock);
2280 
2281         skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
2282 
2283         if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
2284                 getnstimeofday(&ts);
2285 
2286         status |= ts_status;
2287 
2288         switch (po->tp_version) {
2289         case TPACKET_V1:
2290                 h.h1->tp_len = skb->len;
2291                 h.h1->tp_snaplen = snaplen;
2292                 h.h1->tp_mac = macoff;
2293                 h.h1->tp_net = netoff;
2294                 h.h1->tp_sec = ts.tv_sec;
2295                 h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
2296                 hdrlen = sizeof(*h.h1);
2297                 break;
2298         case TPACKET_V2:
2299                 h.h2->tp_len = skb->len;
2300                 h.h2->tp_snaplen = snaplen;
2301                 h.h2->tp_mac = macoff;
2302                 h.h2->tp_net = netoff;
2303                 h.h2->tp_sec = ts.tv_sec;
2304                 h.h2->tp_nsec = ts.tv_nsec;
2305                 if (skb_vlan_tag_present(skb)) {
2306                         h.h2->tp_vlan_tci = skb_vlan_tag_get(skb);
2307                         h.h2->tp_vlan_tpid = ntohs(skb->vlan_proto);
2308                         status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
2309                 } else {
2310                         h.h2->tp_vlan_tci = 0;
2311                         h.h2->tp_vlan_tpid = 0;
2312                 }
2313                 memset(h.h2->tp_padding, 0, sizeof(h.h2->tp_padding));
2314                 hdrlen = sizeof(*h.h2);
2315                 break;
2316         case TPACKET_V3:
2317                 /* tp_nxt_offset,vlan are already populated above.
2318                  * So DONT clear those fields here
2319                  */
2320                 h.h3->tp_status |= status;
2321                 h.h3->tp_len = skb->len;
2322                 h.h3->tp_snaplen = snaplen;
2323                 h.h3->tp_mac = macoff;
2324                 h.h3->tp_net = netoff;
2325                 h.h3->tp_sec  = ts.tv_sec;
2326                 h.h3->tp_nsec = ts.tv_nsec;
2327                 memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding));
2328                 hdrlen = sizeof(*h.h3);
2329                 break;
2330         default:
2331                 BUG();
2332         }
2333 
2334         sll = h.raw + TPACKET_ALIGN(hdrlen);
2335         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
2336         sll->sll_family = AF_PACKET;
2337         sll->sll_hatype = dev->type;
2338         sll->sll_protocol = skb->protocol;
2339         sll->sll_pkttype = skb->pkt_type;
2340         if (unlikely(po->origdev))
2341                 sll->sll_ifindex = orig_dev->ifindex;
2342         else
2343                 sll->sll_ifindex = dev->ifindex;
2344 
2345         smp_mb();
2346 
2347 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
2348         if (po->tp_version <= TPACKET_V2) {
2349                 u8 *start, *end;
2350 
2351                 end = (u8 *) PAGE_ALIGN((unsigned long) h.raw +
2352                                         macoff + snaplen);
2353 
2354                 for (start = h.raw; start < end; start += PAGE_SIZE)
2355                         flush_dcache_page(pgv_to_page(start));
2356         }
2357         smp_wmb();
2358 #endif
2359 
2360         if (po->tp_version <= TPACKET_V2) {
2361                 __packet_set_status(po, h.raw, status);
2362                 sk->sk_data_ready(sk);
2363         } else {
2364                 prb_clear_blk_fill_status(&po->rx_ring);
2365         }
2366 
2367 drop_n_restore:
2368         if (skb_head != skb->data && skb_shared(skb)) {
2369                 skb->data = skb_head;
2370                 skb->len = skb_len;
2371         }
2372 drop:
2373         if (!is_drop_n_account)
2374                 consume_skb(skb);
2375         else
2376                 kfree_skb(skb);
2377         return 0;
2378 
2379 drop_n_account:
2380         is_drop_n_account = true;
2381         po->stats.stats1.tp_drops++;
2382         spin_unlock(&sk->sk_receive_queue.lock);
2383 
2384         sk->sk_data_ready(sk);
2385         kfree_skb(copy_skb);
2386         goto drop_n_restore;
2387 }
2388 
2389 static void tpacket_destruct_skb(struct sk_buff *skb)
2390 {
2391         struct packet_sock *po = pkt_sk(skb->sk);
2392 
2393         if (likely(po->tx_ring.pg_vec)) {
2394                 void *ph;
2395                 __u32 ts;
2396 
2397                 ph = skb_zcopy_get_nouarg(skb);
2398                 packet_dec_pending(&po->tx_ring);
2399 
2400                 ts = __packet_set_timestamp(po, ph, skb);
2401                 __packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts);
2402         }
2403 
2404         sock_wfree(skb);
2405 }
2406 
2407 static void tpacket_set_protocol(const struct net_device *dev,
2408                                  struct sk_buff *skb)
2409 {
2410         if (dev->type == ARPHRD_ETHER) {
2411                 skb_reset_mac_header(skb);
2412                 skb->protocol = eth_hdr(skb)->h_proto;
2413         }
2414 }
2415 
2416 static int __packet_snd_vnet_parse(struct virtio_net_hdr *vnet_hdr, size_t len)
2417 {
2418         if ((vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
2419             (__virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
2420              __virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2 >
2421               __virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len)))
2422                 vnet_hdr->hdr_len = __cpu_to_virtio16(vio_le(),
2423                          __virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
2424                         __virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2);
2425 
2426         if (__virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len) > len)
2427                 return -EINVAL;
2428 
2429         return 0;
2430 }
2431 
2432 static int packet_snd_vnet_parse(struct msghdr *msg, size_t *len,
2433                                  struct virtio_net_hdr *vnet_hdr)
2434 {
2435         if (*len < sizeof(*vnet_hdr))
2436                 return -EINVAL;
2437         *len -= sizeof(*vnet_hdr);
2438 
2439         if (!copy_from_iter_full(vnet_hdr, sizeof(*vnet_hdr), &msg->msg_iter))
2440                 return -EFAULT;
2441 
2442         return __packet_snd_vnet_parse(vnet_hdr, *len);
2443 }
2444 
2445 static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
2446                 void *frame, struct net_device *dev, void *data, int tp_len,
2447                 __be16 proto, unsigned char *addr, int hlen, int copylen,
2448                 const struct sockcm_cookie *sockc)
2449 {
2450         union tpacket_uhdr ph;
2451         int to_write, offset, len, nr_frags, len_max;
2452         struct socket *sock = po->sk.sk_socket;
2453         struct page *page;
2454         int err;
2455 
2456         ph.raw = frame;
2457 
2458         skb->protocol = proto;
2459         skb->dev = dev;
2460         skb->priority = po->sk.sk_priority;
2461         skb->mark = po->sk.sk_mark;
2462         skb->tstamp = sockc->transmit_time;
2463         sock_tx_timestamp(&po->sk, sockc->tsflags, &skb_shinfo(skb)->tx_flags);
2464         skb_zcopy_set_nouarg(skb, ph.raw);
2465 
2466         skb_reserve(skb, hlen);
2467         skb_reset_network_header(skb);
2468 
2469         to_write = tp_len;
2470 
2471         if (sock->type == SOCK_DGRAM) {
2472                 err = dev_hard_header(skb, dev, ntohs(proto), addr,
2473                                 NULL, tp_len);
2474                 if (unlikely(err < 0))
2475                         return -EINVAL;
2476         } else if (copylen) {
2477                 int hdrlen = min_t(int, copylen, tp_len);
2478 
2479                 skb_push(skb, dev->hard_header_len);
2480                 skb_put(skb, copylen - dev->hard_header_len);
2481                 err = skb_store_bits(skb, 0, data, hdrlen);
2482                 if (unlikely(err))
2483                         return err;
2484                 if (!dev_validate_header(dev, skb->data, hdrlen))
2485                         return -EINVAL;
2486                 if (!skb->protocol)
2487                         tpacket_set_protocol(dev, skb);
2488 
2489                 data += hdrlen;
2490                 to_write -= hdrlen;
2491         }
2492 
2493         offset = offset_in_page(data);
2494         len_max = PAGE_SIZE - offset;
2495         len = ((to_write > len_max) ? len_max : to_write);
2496 
2497         skb->data_len = to_write;
2498         skb->len += to_write;
2499         skb->truesize += to_write;
2500         refcount_add(to_write, &po->sk.sk_wmem_alloc);
2501 
2502         while (likely(to_write)) {
2503                 nr_frags = skb_shinfo(skb)->nr_frags;
2504 
2505                 if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
2506                         pr_err("Packet exceed the number of skb frags(%lu)\n",
2507                                MAX_SKB_FRAGS);
2508                         return -EFAULT;
2509                 }
2510 
2511                 page = pgv_to_page(data);
2512                 data += len;
2513                 flush_dcache_page(page);
2514                 get_page(page);
2515                 skb_fill_page_desc(skb, nr_frags, page, offset, len);
2516                 to_write -= len;
2517                 offset = 0;
2518                 len_max = PAGE_SIZE;
2519                 len = ((to_write > len_max) ? len_max : to_write);
2520         }
2521 
2522         skb_probe_transport_header(skb, 0);
2523 
2524         return tp_len;
2525 }
2526 
2527 static int tpacket_parse_header(struct packet_sock *po, void *frame,
2528                                 int size_max, void **data)
2529 {
2530         union tpacket_uhdr ph;
2531         int tp_len, off;
2532 
2533         ph.raw = frame;
2534 
2535         switch (po->tp_version) {
2536         case TPACKET_V3:
2537                 if (ph.h3->tp_next_offset != 0) {
2538                         pr_warn_once("variable sized slot not supported");
2539                         return -EINVAL;
2540                 }
2541                 tp_len = ph.h3->tp_len;
2542                 break;
2543         case TPACKET_V2:
2544                 tp_len = ph.h2->tp_len;
2545                 break;
2546         default:
2547                 tp_len = ph.h1->tp_len;
2548                 break;
2549         }
2550         if (unlikely(tp_len > size_max)) {
2551                 pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
2552                 return -EMSGSIZE;
2553         }
2554 
2555         if (unlikely(po->tp_tx_has_off)) {
2556                 int off_min, off_max;
2557 
2558                 off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
2559                 off_max = po->tx_ring.frame_size - tp_len;
2560                 if (po->sk.sk_type == SOCK_DGRAM) {
2561                         switch (po->tp_version) {
2562                         case TPACKET_V3:
2563                                 off = ph.h3->tp_net;
2564                                 break;
2565                         case TPACKET_V2:
2566                                 off = ph.h2->tp_net;
2567                                 break;
2568                         default:
2569                                 off = ph.h1->tp_net;
2570                                 break;
2571                         }
2572                 } else {
2573                         switch (po->tp_version) {
2574                         case TPACKET_V3:
2575                                 off = ph.h3->tp_mac;
2576                                 break;
2577                         case TPACKET_V2:
2578                                 off = ph.h2->tp_mac;
2579                                 break;
2580                         default:
2581                                 off = ph.h1->tp_mac;
2582                                 break;
2583                         }
2584                 }
2585                 if (unlikely((off < off_min) || (off_max < off)))
2586                         return -EINVAL;
2587         } else {
2588                 off = po->tp_hdrlen - sizeof(struct sockaddr_ll);
2589         }
2590 
2591         *data = frame + off;
2592         return tp_len;
2593 }
2594 
2595 static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
2596 {
2597         struct sk_buff *skb;
2598         struct net_device *dev;
2599         struct virtio_net_hdr *vnet_hdr = NULL;
2600         struct sockcm_cookie sockc;
2601         __be16 proto;
2602         int err, reserve = 0;
2603         void *ph;
2604         DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
2605         bool need_wait = !(msg->msg_flags & MSG_DONTWAIT);
2606         int tp_len, size_max;
2607         unsigned char *addr;
2608         void *data;
2609         int len_sum = 0;
2610         int status = TP_STATUS_AVAILABLE;
2611         int hlen, tlen, copylen = 0;
2612 
2613         mutex_lock(&po->pg_vec_lock);
2614 
2615         if (likely(saddr == NULL)) {
2616                 dev     = packet_cached_dev_get(po);
2617                 proto   = po->num;
2618                 addr    = NULL;
2619         } else {
2620                 err = -EINVAL;
2621                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
2622                         goto out;
2623                 if (msg->msg_namelen < (saddr->sll_halen
2624                                         + offsetof(struct sockaddr_ll,
2625                                                 sll_addr)))
2626                         goto out;
2627                 proto   = saddr->sll_protocol;
2628                 addr    = saddr->sll_addr;
2629                 dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
2630         }
2631 
2632         err = -ENXIO;
2633         if (unlikely(dev == NULL))
2634                 goto out;
2635         err = -ENETDOWN;
2636         if (unlikely(!(dev->flags & IFF_UP)))
2637                 goto out_put;
2638 
2639         sockcm_init(&sockc, &po->sk);
2640         if (msg->msg_controllen) {
2641                 err = sock_cmsg_send(&po->sk, msg, &sockc);
2642                 if (unlikely(err))
2643                         goto out_put;
2644         }
2645 
2646         if (po->sk.sk_socket->type == SOCK_RAW)
2647                 reserve = dev->hard_header_len;
2648         size_max = po->tx_ring.frame_size
2649                 - (po->tp_hdrlen - sizeof(struct sockaddr_ll));
2650 
2651         if ((size_max > dev->mtu + reserve + VLAN_HLEN) && !po->has_vnet_hdr)
2652                 size_max = dev->mtu + reserve + VLAN_HLEN;
2653 
2654         do {
2655                 ph = packet_current_frame(po, &po->tx_ring,
2656                                           TP_STATUS_SEND_REQUEST);
2657                 if (unlikely(ph == NULL)) {
2658                         if (need_wait && need_resched())
2659                                 schedule();
2660                         continue;
2661                 }
2662 
2663                 skb = NULL;
2664                 tp_len = tpacket_parse_header(po, ph, size_max, &data);
2665                 if (tp_len < 0)
2666                         goto tpacket_error;
2667 
2668                 status = TP_STATUS_SEND_REQUEST;
2669                 hlen = LL_RESERVED_SPACE(dev);
2670                 tlen = dev->needed_tailroom;
2671                 if (po->has_vnet_hdr) {
2672                         vnet_hdr = data;
2673                         data += sizeof(*vnet_hdr);
2674                         tp_len -= sizeof(*vnet_hdr);
2675                         if (tp_len < 0 ||
2676                             __packet_snd_vnet_parse(vnet_hdr, tp_len)) {
2677                                 tp_len = -EINVAL;
2678                                 goto tpacket_error;
2679                         }
2680                         copylen = __virtio16_to_cpu(vio_le(),
2681                                                     vnet_hdr->hdr_len);
2682                 }
2683                 copylen = max_t(int, copylen, dev->hard_header_len);
2684                 skb = sock_alloc_send_skb(&po->sk,
2685                                 hlen + tlen + sizeof(struct sockaddr_ll) +
2686                                 (copylen - dev->hard_header_len),
2687                                 !need_wait, &err);
2688 
2689                 if (unlikely(skb == NULL)) {
2690                         /* we assume the socket was initially writeable ... */
2691                         if (likely(len_sum > 0))
2692                                 err = len_sum;
2693                         goto out_status;
2694                 }
2695                 tp_len = tpacket_fill_skb(po, skb, ph, dev, data, tp_len, proto,
2696                                           addr, hlen, copylen, &sockc);
2697                 if (likely(tp_len >= 0) &&
2698                     tp_len > dev->mtu + reserve &&
2699                     !po->has_vnet_hdr &&
2700                     !packet_extra_vlan_len_allowed(dev, skb))
2701                         tp_len = -EMSGSIZE;
2702 
2703                 if (unlikely(tp_len < 0)) {
2704 tpacket_error:
2705                         if (po->tp_loss) {
2706                                 __packet_set_status(po, ph,
2707                                                 TP_STATUS_AVAILABLE);
2708                                 packet_increment_head(&po->tx_ring);
2709                                 kfree_skb(skb);
2710                                 continue;
2711                         } else {
2712                                 status = TP_STATUS_WRONG_FORMAT;
2713                                 err = tp_len;
2714                                 goto out_status;
2715                         }
2716                 }
2717 
2718                 if (po->has_vnet_hdr) {
2719                         if (virtio_net_hdr_to_skb(skb, vnet_hdr, vio_le())) {
2720                                 tp_len = -EINVAL;
2721                                 goto tpacket_error;
2722                         }
2723                         virtio_net_hdr_set_proto(skb, vnet_hdr);
2724                 }
2725 
2726                 skb->destructor = tpacket_destruct_skb;
2727                 __packet_set_status(po, ph, TP_STATUS_SENDING);
2728                 packet_inc_pending(&po->tx_ring);
2729 
2730                 status = TP_STATUS_SEND_REQUEST;
2731                 err = po->xmit(skb);
2732                 if (unlikely(err > 0)) {
2733                         err = net_xmit_errno(err);
2734                         if (err && __packet_get_status(po, ph) ==
2735                                    TP_STATUS_AVAILABLE) {
2736                                 /* skb was destructed already */
2737                                 skb = NULL;
2738                                 goto out_status;
2739                         }
2740                         /*
2741                          * skb was dropped but not destructed yet;
2742                          * let's treat it like congestion or err < 0
2743                          */
2744                         err = 0;
2745                 }
2746                 packet_increment_head(&po->tx_ring);
2747                 len_sum += tp_len;
2748         } while (likely((ph != NULL) ||
2749                 /* Note: packet_read_pending() might be slow if we have
2750                  * to call it as it's per_cpu variable, but in fast-path
2751                  * we already short-circuit the loop with the first
2752                  * condition, and luckily don't have to go that path
2753                  * anyway.
2754                  */
2755                  (need_wait && packet_read_pending(&po->tx_ring))));
2756 
2757         err = len_sum;
2758         goto out_put;
2759 
2760 out_status:
2761         __packet_set_status(po, ph, status);
2762         kfree_skb(skb);
2763 out_put:
2764         dev_put(dev);
2765 out:
2766         mutex_unlock(&po->pg_vec_lock);
2767         return err;
2768 }
2769 
2770 static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,
2771                                         size_t reserve, size_t len,
2772                                         size_t linear, int noblock,
2773                                         int *err)
2774 {
2775         struct sk_buff *skb;
2776 
2777         /* Under a page?  Don't bother with paged skb. */
2778         if (prepad + len < PAGE_SIZE || !linear)
2779                 linear = len;
2780 
2781         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
2782                                    err, 0);
2783         if (!skb)
2784                 return NULL;
2785 
2786         skb_reserve(skb, reserve);
2787         skb_put(skb, linear);
2788         skb->data_len = len - linear;
2789         skb->len += len - linear;
2790 
2791         return skb;
2792 }
2793 
2794 static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
2795 {
2796         struct sock *sk = sock->sk;
2797         DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
2798         struct sk_buff *skb;
2799         struct net_device *dev;
2800         __be16 proto;
2801         unsigned char *addr;
2802         int err, reserve = 0;
2803         struct sockcm_cookie sockc;
2804         struct virtio_net_hdr vnet_hdr = { 0 };
2805         int offset = 0;
2806         struct packet_sock *po = pkt_sk(sk);
2807         bool has_vnet_hdr = false;
2808         int hlen, tlen, linear;
2809         int extra_len = 0;
2810 
2811         /*
2812          *      Get and verify the address.
2813          */
2814 
2815         if (likely(saddr == NULL)) {
2816                 dev     = packet_cached_dev_get(po);
2817                 proto   = po->num;
2818                 addr    = NULL;
2819         } else {
2820                 err = -EINVAL;
2821                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
2822                         goto out;
2823                 if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
2824                         goto out;
2825                 proto   = saddr->sll_protocol;
2826                 addr    = saddr->sll_addr;
2827                 dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
2828         }
2829 
2830         err = -ENXIO;
2831         if (unlikely(dev == NULL))
2832                 goto out_unlock;
2833         err = -ENETDOWN;
2834         if (unlikely(!(dev->flags & IFF_UP)))
2835                 goto out_unlock;
2836 
2837         sockcm_init(&sockc, sk);
2838         sockc.mark = sk->sk_mark;
2839         if (msg->msg_controllen) {
2840                 err = sock_cmsg_send(sk, msg, &sockc);
2841                 if (unlikely(err))
2842                         goto out_unlock;
2843         }
2844 
2845         if (sock->type == SOCK_RAW)
2846                 reserve = dev->hard_header_len;
2847         if (po->has_vnet_hdr) {
2848                 err = packet_snd_vnet_parse(msg, &len, &vnet_hdr);
2849                 if (err)
2850                         goto out_unlock;
2851                 has_vnet_hdr = true;
2852         }
2853 
2854         if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
2855                 if (!netif_supports_nofcs(dev)) {
2856                         err = -EPROTONOSUPPORT;
2857                         goto out_unlock;
2858                 }
2859                 extra_len = 4; /* We're doing our own CRC */
2860         }
2861 
2862         err = -EMSGSIZE;
2863         if (!vnet_hdr.gso_type &&
2864             (len > dev->mtu + reserve + VLAN_HLEN + extra_len))
2865                 goto out_unlock;
2866 
2867         err = -ENOBUFS;
2868         hlen = LL_RESERVED_SPACE(dev);
2869         tlen = dev->needed_tailroom;
2870         linear = __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len);
2871         linear = max(linear, min_t(int, len, dev->hard_header_len));
2872         skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, linear,
2873                                msg->msg_flags & MSG_DONTWAIT, &err);
2874         if (skb == NULL)
2875                 goto out_unlock;
2876 
2877         skb_reset_network_header(skb);
2878 
2879         err = -EINVAL;
2880         if (sock->type == SOCK_DGRAM) {
2881                 offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);
2882                 if (unlikely(offset < 0))
2883                         goto out_free;
2884         } else if (reserve) {
2885                 skb_reserve(skb, -reserve);
2886                 if (len < reserve)
2887                         skb_reset_network_header(skb);
2888         }
2889 
2890         /* Returns -EFAULT on error */
2891         err = skb_copy_datagram_from_iter(skb, offset, &msg->msg_iter, len);
2892         if (err)
2893                 goto out_free;
2894 
2895         if (sock->type == SOCK_RAW &&
2896             !dev_validate_header(dev, skb->data, len)) {
2897                 err = -EINVAL;
2898                 goto out_free;
2899         }
2900 
2901         sock_tx_timestamp(sk, sockc.tsflags, &skb_shinfo(skb)->tx_flags);
2902 
2903         if (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&
2904             !packet_extra_vlan_len_allowed(dev, skb)) {
2905                 err = -EMSGSIZE;
2906                 goto out_free;
2907         }
2908 
2909         skb->protocol = proto;
2910         skb->dev = dev;
2911         skb->priority = sk->sk_priority;
2912         skb->mark = sockc.mark;
2913         skb->tstamp = sockc.transmit_time;
2914 
2915         if (has_vnet_hdr) {
2916                 err = virtio_net_hdr_to_skb(skb, &vnet_hdr, vio_le());
2917                 if (err)
2918                         goto out_free;
2919                 len += sizeof(vnet_hdr);
2920                 virtio_net_hdr_set_proto(skb, &vnet_hdr);
2921         }
2922 
2923         skb_probe_transport_header(skb, reserve);
2924 
2925         if (unlikely(extra_len == 4))
2926                 skb->no_fcs = 1;
2927 
2928         err = po->xmit(skb);
2929         if (err > 0 && (err = net_xmit_errno(err)) != 0)
2930                 goto out_unlock;
2931 
2932         dev_put(dev);
2933 
2934         return len;
2935 
2936 out_free:
2937         kfree_skb(skb);
2938 out_unlock:
2939         if (dev)
2940                 dev_put(dev);
2941 out:
2942         return err;
2943 }
2944 
2945 static int packet_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
2946 {
2947         struct sock *sk = sock->sk;
2948         struct packet_sock *po = pkt_sk(sk);
2949 
2950         if (po->tx_ring.pg_vec)
2951                 return tpacket_snd(po, msg);
2952         else
2953                 return packet_snd(sock, msg, len);
2954 }
2955 
2956 /*
2957  *      Close a PACKET socket. This is fairly simple. We immediately go
2958  *      to 'closed' state and remove our protocol entry in the device list.
2959  */
2960 
2961 static int packet_release(struct socket *sock)
2962 {
2963         struct sock *sk = sock->sk;
2964         struct packet_sock *po;
2965         struct packet_fanout *f;
2966         struct net *net;
2967         union tpacket_req_u req_u;
2968 
2969         if (!sk)
2970                 return 0;
2971 
2972         net = sock_net(sk);
2973         po = pkt_sk(sk);
2974 
2975         mutex_lock(&net->packet.sklist_lock);
2976         sk_del_node_init_rcu(sk);
2977         mutex_unlock(&net->packet.sklist_lock);
2978 
2979         preempt_disable();
2980         sock_prot_inuse_add(net, sk->sk_prot, -1);
2981         preempt_enable();
2982 
2983         spin_lock(&po->bind_lock);
2984         unregister_prot_hook(sk, false);
2985         packet_cached_dev_reset(po);
2986 
2987         if (po->prot_hook.dev) {
2988                 dev_put(po->prot_hook.dev);
2989                 po->prot_hook.dev = NULL;
2990         }
2991         spin_unlock(&po->bind_lock);
2992 
2993         packet_flush_mclist(sk);
2994 
2995         lock_sock(sk);
2996         if (po->rx_ring.pg_vec) {
2997                 memset(&req_u, 0, sizeof(req_u));
2998                 packet_set_ring(sk, &req_u, 1, 0);
2999         }
3000 
3001         if (po->tx_ring.pg_vec) {
3002                 memset(&req_u, 0, sizeof(req_u));
3003                 packet_set_ring(sk, &req_u, 1, 1);
3004         }
3005         release_sock(sk);
3006 
3007         f = fanout_release(sk);
3008 
3009         synchronize_net();
3010 
3011         if (f) {
3012                 kfree(po->rollover);
3013                 fanout_release_data(f);
3014                 kfree(f);
3015         }
3016         /*
3017          *      Now the socket is dead. No more input will appear.
3018          */
3019         sock_orphan(sk);
3020         sock->sk = NULL;
3021 
3022         /* Purge queues */
3023 
3024         skb_queue_purge(&sk->sk_receive_queue);
3025         packet_free_pending(po);
3026         sk_refcnt_debug_release(sk);
3027 
3028         sock_put(sk);
3029         return 0;
3030 }
3031 
3032 /*
3033  *      Attach a packet hook.
3034  */
3035 
3036 static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
3037                           __be16 proto)
3038 {
3039         struct packet_sock *po = pkt_sk(sk);
3040         struct net_device *dev_curr;
3041         __be16 proto_curr;
3042         bool need_rehook;
3043         struct net_device *dev = NULL;
3044         int ret = 0;
3045         bool unlisted = false;
3046 
3047         lock_sock(sk);
3048         spin_lock(&po->bind_lock);
3049         rcu_read_lock();
3050 
3051         if (po->fanout) {
3052                 ret = -EINVAL;
3053                 goto out_unlock;
3054         }
3055 
3056         if (name) {
3057                 dev = dev_get_by_name_rcu(sock_net(sk), name);
3058                 if (!dev) {
3059                         ret = -ENODEV;
3060                         goto out_unlock;
3061                 }
3062         } else if (ifindex) {
3063                 dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
3064                 if (!dev) {
3065                         ret = -ENODEV;
3066                         goto out_unlock;
3067                 }
3068         }
3069 
3070         if (dev)
3071                 dev_hold(dev);
3072 
3073         proto_curr = po->prot_hook.type;
3074         dev_curr = po->prot_hook.dev;
3075 
3076         need_rehook = proto_curr != proto || dev_curr != dev;
3077 
3078         if (need_rehook) {
3079                 if (po->running) {
3080                         rcu_read_unlock();
3081                         /* prevents packet_notifier() from calling
3082                          * register_prot_hook()
3083                          */
3084                         po->num = 0;
3085                         __unregister_prot_hook(sk, true);
3086                         rcu_read_lock();
3087                         dev_curr = po->prot_hook.dev;
3088                         if (dev)
3089                                 unlisted = !dev_get_by_index_rcu(sock_net(sk),
3090                                                                  dev->ifindex);
3091                 }
3092 
3093                 BUG_ON(po->running);
3094                 po->num = proto;
3095                 po->prot_hook.type = proto;
3096 
3097                 if (unlikely(unlisted)) {
3098                         dev_put(dev);
3099                         po->prot_hook.dev = NULL;
3100                         po->ifindex = -1;
3101                         packet_cached_dev_reset(po);
3102                 } else {
3103                         po->prot_hook.dev = dev;
3104                         po->ifindex = dev ? dev->ifindex : 0;
3105                         packet_cached_dev_assign(po, dev);
3106                 }
3107         }
3108         if (dev_curr)
3109                 dev_put(dev_curr);
3110 
3111         if (proto == 0 || !need_rehook)
3112                 goto out_unlock;
3113 
3114         if (!unlisted && (!dev || (dev->flags & IFF_UP))) {
3115                 register_prot_hook(sk);
3116         } else {
3117                 sk->sk_err = ENETDOWN;
3118                 if (!sock_flag(sk, SOCK_DEAD))
3119                         sk->sk_error_report(sk);
3120         }
3121 
3122 out_unlock:
3123         rcu_read_unlock();
3124         spin_unlock(&po->bind_lock);
3125         release_sock(sk);
3126         return ret;
3127 }
3128 
3129 /*
3130  *      Bind a packet socket to a device
3131  */
3132 
3133 static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
3134                             int addr_len)
3135 {
3136         struct sock *sk = sock->sk;
3137         char name[sizeof(uaddr->sa_data) + 1];
3138 
3139         /*
3140          *      Check legality
3141          */
3142 
3143         if (addr_len != sizeof(struct sockaddr))
3144                 return -EINVAL;
3145         /* uaddr->sa_data comes from the userspace, it's not guaranteed to be
3146          * zero-terminated.
3147          */
3148         memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data));
3149         name[sizeof(uaddr->sa_data)] = 0;
3150 
3151         return packet_do_bind(sk, name, 0, pkt_sk(sk)->num);
3152 }
3153 
3154 static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
3155 {
3156         struct sockaddr_ll *sll = (struct sockaddr_ll *)uaddr;
3157         struct sock *sk = sock->sk;
3158 
3159         /*
3160          *      Check legality
3161          */
3162 
3163         if (addr_len < sizeof(struct sockaddr_ll))
3164                 return -EINVAL;
3165         if (sll->sll_family != AF_PACKET)
3166                 return -EINVAL;
3167 
3168         return packet_do_bind(sk, NULL, sll->sll_ifindex,
3169                               sll->sll_protocol ? : pkt_sk(sk)->num);
3170 }
3171 
3172 static struct proto packet_proto = {
3173         .name     = "PACKET",
3174         .owner    = THIS_MODULE,
3175         .obj_size = sizeof(struct packet_sock),
3176 };
3177 
3178 /*
3179  *      Create a packet of type SOCK_PACKET.
3180  */
3181 
3182 static int packet_create(struct net *net, struct socket *sock, int protocol,
3183                          int kern)
3184 {
3185         struct sock *sk;
3186         struct packet_sock *po;
3187         __be16 proto = (__force __be16)protocol; /* weird, but documented */
3188         int err;
3189 
3190         if (!ns_capable(net->user_ns, CAP_NET_RAW))
3191                 return -EPERM;
3192         if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
3193             sock->type != SOCK_PACKET)
3194                 return -ESOCKTNOSUPPORT;
3195 
3196         sock->state = SS_UNCONNECTED;
3197 
3198         err = -ENOBUFS;
3199         sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto, kern);
3200         if (sk == NULL)
3201                 goto out;
3202 
3203         sock->ops = &packet_ops;
3204         if (sock->type == SOCK_PACKET)
3205                 sock->ops = &packet_ops_spkt;
3206 
3207         sock_init_data(sock, sk);
3208 
3209         po = pkt_sk(sk);
3210         sk->sk_family = PF_PACKET;
3211         po->num = proto;
3212         po->xmit = dev_queue_xmit;
3213 
3214         err = packet_alloc_pending(po);
3215         if (err)
3216                 goto out2;
3217 
3218         packet_cached_dev_reset(po);
3219 
3220         sk->sk_destruct = packet_sock_destruct;
3221         sk_refcnt_debug_inc(sk);
3222 
3223         /*
3224          *      Attach a protocol block
3225          */
3226 
3227         spin_lock_init(&po->bind_lock);
3228         mutex_init(&po->pg_vec_lock);
3229         po->rollover = NULL;
3230         po->prot_hook.func = packet_rcv;
3231 
3232         if (sock->type == SOCK_PACKET)
3233                 po->prot_hook.func = packet_rcv_spkt;
3234 
3235         po->prot_hook.af_packet_priv = sk;
3236 
3237         if (proto) {
3238                 po->prot_hook.type = proto;
3239                 __register_prot_hook(sk);
3240         }
3241 
3242         mutex_lock(&net->packet.sklist_lock);
3243         sk_add_node_rcu(sk, &net->packet.sklist);
3244         mutex_unlock(&net->packet.sklist_lock);
3245 
3246         preempt_disable();
3247         sock_prot_inuse_add(net, &packet_proto, 1);
3248         preempt_enable();
3249 
3250         return 0;
3251 out2:
3252         sk_free(sk);
3253 out:
3254         return err;
3255 }
3256 
3257 /*
3258  *      Pull a packet from our receive queue and hand it to the user.
3259  *      If necessary we block.
3260  */
3261 
3262 static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
3263                           int flags)
3264 {
3265         struct sock *sk = sock->sk;
3266         struct sk_buff *skb;
3267         int copied, err;
3268         int vnet_hdr_len = 0;
3269         unsigned int origlen = 0;
3270 
3271         err = -EINVAL;
3272         if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT|MSG_ERRQUEUE))
3273                 goto out;
3274 
3275 #if 0
3276         /* What error should we return now? EUNATTACH? */
3277         if (pkt_sk(sk)->ifindex < 0)
3278                 return -ENODEV;
3279 #endif
3280 
3281         if (flags & MSG_ERRQUEUE) {
3282                 err = sock_recv_errqueue(sk, msg, len,
3283                                          SOL_PACKET, PACKET_TX_TIMESTAMP);
3284                 goto out;
3285         }
3286 
3287         /*
3288          *      Call the generic datagram receiver. This handles all sorts
3289          *      of horrible races and re-entrancy so we can forget about it
3290          *      in the protocol layers.
3291          *
3292          *      Now it will return ENETDOWN, if device have just gone down,
3293          *      but then it will block.
3294          */
3295 
3296         skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
3297 
3298         /*
3299          *      An error occurred so return it. Because skb_recv_datagram()
3300          *      handles the blocking we don't see and worry about blocking
3301          *      retries.
3302          */
3303 
3304         if (skb == NULL)
3305                 goto out;
3306 
3307         if (pkt_sk(sk)->pressure)
3308                 packet_rcv_has_room(pkt_sk(sk), NULL);
3309 
3310         if (pkt_sk(sk)->has_vnet_hdr) {
3311                 err = packet_rcv_vnet(msg, skb, &len);
3312                 if (err)
3313                         goto out_free;
3314                 vnet_hdr_len = sizeof(struct virtio_net_hdr);
3315         }
3316 
3317         /* You lose any data beyond the buffer you gave. If it worries
3318          * a user program they can ask the device for its MTU
3319          * anyway.
3320          */
3321         copied = skb->len;
3322         if (copied > len) {
3323                 copied = len;
3324                 msg->msg_flags |= MSG_TRUNC;
3325         }
3326 
3327         err = skb_copy_datagram_msg(skb, 0, msg, copied);
3328         if (err)
3329                 goto out_free;
3330 
3331         if (sock->type != SOCK_PACKET) {
3332                 struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
3333 
3334                 /* Original length was stored in sockaddr_ll fields */
3335                 origlen = PACKET_SKB_CB(skb)->sa.origlen;
3336                 sll->sll_family = AF_PACKET;
3337                 sll->sll_protocol = skb->protocol;
3338         }
3339 
3340         sock_recv_ts_and_drops(msg, sk, skb);
3341 
3342         if (msg->msg_name) {
3343                 /* If the address length field is there to be filled
3344                  * in, we fill it in now.
3345                  */
3346                 if (sock->type == SOCK_PACKET) {
3347                         __sockaddr_check_size(sizeof(struct sockaddr_pkt));
3348                         msg->msg_namelen = sizeof(struct sockaddr_pkt);
3349                 } else {
3350                         struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
3351 
3352                         msg->msg_namelen = sll->sll_halen +
3353                                 offsetof(struct sockaddr_ll, sll_addr);
3354                 }
3355                 memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa,
3356                        msg->msg_namelen);
3357         }
3358 
3359         if (pkt_sk(sk)->auxdata) {
3360                 struct tpacket_auxdata aux;
3361 
3362                 aux.tp_status = TP_STATUS_USER;
3363                 if (skb->ip_summed == CHECKSUM_PARTIAL)
3364                         aux.tp_status |= TP_STATUS_CSUMNOTREADY;
3365                 else if (skb->pkt_type != PACKET_OUTGOING &&
3366                          (skb->ip_summed == CHECKSUM_COMPLETE ||
3367                           skb_csum_unnecessary(skb)))
3368                         aux.tp_status |= TP_STATUS_CSUM_VALID;
3369 
3370                 aux.tp_len = origlen;
3371                 aux.tp_snaplen = skb->len;
3372                 aux.tp_mac = 0;
3373                 aux.tp_net = skb_network_offset(skb);
3374                 if (skb_vlan_tag_present(skb)) {
3375                         aux.tp_vlan_tci = skb_vlan_tag_get(skb);
3376                         aux.tp_vlan_tpid = ntohs(skb->vlan_proto);
3377                         aux.tp_status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
3378                 } else {
3379                         aux.tp_vlan_tci = 0;
3380                         aux.tp_vlan_tpid = 0;
3381                 }
3382                 put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
3383         }
3384 
3385         /*
3386          *      Free or return the buffer as appropriate. Again this
3387          *      hides all the races and re-entrancy issues from us.
3388          */
3389         err = vnet_hdr_len + ((flags&MSG_TRUNC) ? skb->len : copied);
3390 
3391 out_free:
3392         skb_free_datagram(sk, skb);
3393 out:
3394         return err;
3395 }
3396 
3397 static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
3398                                int peer)
3399 {
3400         struct net_device *dev;
3401         struct sock *sk = sock->sk;
3402 
3403         if (peer)
3404                 return -EOPNOTSUPP;
3405 
3406         uaddr->sa_family = AF_PACKET;
3407         memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
3408         rcu_read_lock();
3409         dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
3410         if (dev)
3411                 strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
3412         rcu_read_unlock();
3413 
3414         return sizeof(*uaddr);
3415 }
3416 
3417 static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
3418                           int peer)
3419 {
3420         struct net_device *dev;
3421         struct sock *sk = sock->sk;
3422         struct packet_sock *po = pkt_sk(sk);
3423         DECLARE_SOCKADDR(struct sockaddr_ll *, sll, uaddr);
3424 
3425         if (peer)
3426                 return -EOPNOTSUPP;
3427 
3428         sll->sll_family = AF_PACKET;
3429         sll->sll_ifindex = po->ifindex;
3430         sll->sll_protocol = po->num;
3431         sll->sll_pkttype = 0;
3432         rcu_read_lock();
3433         dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
3434         if (dev) {
3435                 sll->sll_hatype = dev->type;
3436                 sll->sll_halen = dev->addr_len;
3437                 memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
3438         } else {
3439                 sll->sll_hatype = 0;    /* Bad: we have no ARPHRD_UNSPEC */
3440                 sll->sll_halen = 0;
3441         }
3442         rcu_read_unlock();
3443 
3444         return offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
3445 }
3446 
3447 static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
3448                          int what)
3449 {
3450         switch (i->type) {
3451         case PACKET_MR_MULTICAST:
3452                 if (i->alen != dev->addr_len)
3453                         return -EINVAL;
3454                 if (what > 0)
3455                         return dev_mc_add(dev, i->addr);
3456                 else
3457                         return dev_mc_del(dev, i->addr);
3458                 break;
3459         case PACKET_MR_PROMISC:
3460                 return dev_set_promiscuity(dev, what);
3461         case PACKET_MR_ALLMULTI:
3462                 return dev_set_allmulti(dev, what);
3463         case PACKET_MR_UNICAST:
3464                 if (i->alen != dev->addr_len)
3465                         return -EINVAL;
3466                 if (what > 0)
3467                         return dev_uc_add(dev, i->addr);
3468                 else
3469                         return dev_uc_del(dev, i->addr);
3470                 break;
3471         default:
3472                 break;
3473         }
3474         return 0;
3475 }
3476 
3477 static void packet_dev_mclist_delete(struct net_device *dev,
3478                                      struct packet_mclist **mlp)
3479 {
3480         struct packet_mclist *ml;
3481 
3482         while ((ml = *mlp) != NULL) {
3483                 if (ml->ifindex == dev->ifindex) {
3484                         packet_dev_mc(dev, ml, -1);
3485                         *mlp = ml->next;
3486                         kfree(ml);
3487                 } else
3488                         mlp = &ml->next;
3489         }
3490 }
3491 
3492 static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
3493 {
3494         struct packet_sock *po = pkt_sk(sk);
3495         struct packet_mclist *ml, *i;
3496         struct net_device *dev;
3497         int err;
3498 
3499         rtnl_lock();
3500 
3501         err = -ENODEV;
3502         dev = __dev_get_by_index(sock_net(sk), mreq->mr_ifindex);
3503         if (!dev)
3504                 goto done;
3505 
3506         err = -EINVAL;
3507         if (mreq->mr_alen > dev->addr_len)
3508                 goto done;
3509 
3510         err = -ENOBUFS;
3511         i = kmalloc(sizeof(*i), GFP_KERNEL);
3512         if (i == NULL)
3513                 goto done;
3514 
3515         err = 0;
3516         for (ml = po->mclist; ml; ml = ml->next) {
3517                 if (ml->ifindex == mreq->mr_ifindex &&
3518                     ml->type == mreq->mr_type &&
3519                     ml->alen == mreq->mr_alen &&
3520                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
3521                         ml->count++;
3522                         /* Free the new element ... */
3523                         kfree(i);
3524                         goto done;
3525                 }
3526         }
3527 
3528         i->type = mreq->mr_type;
3529         i->ifindex = mreq->mr_ifindex;
3530         i->alen = mreq->mr_alen;
3531         memcpy(i->addr, mreq->mr_address, i->alen);
3532         memset(i->addr + i->alen, 0, sizeof(i->addr) - i->alen);
3533         i->count = 1;
3534         i->next = po->mclist;
3535         po->mclist = i;
3536         err = packet_dev_mc(dev, i, 1);
3537         if (err) {
3538                 po->mclist = i->next;
3539                 kfree(i);
3540         }
3541 
3542 done:
3543         rtnl_unlock();
3544         return err;
3545 }
3546 
3547 static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
3548 {
3549         struct packet_mclist *ml, **mlp;
3550 
3551         rtnl_lock();
3552 
3553         for (mlp = &pkt_sk(sk)->mclist; (ml = *mlp) != NULL; mlp = &ml->next) {
3554                 if (ml->ifindex == mreq->mr_ifindex &&
3555                     ml->type == mreq->mr_type &&
3556                     ml->alen == mreq->mr_alen &&
3557                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
3558                         if (--ml->count == 0) {
3559                                 struct net_device *dev;
3560                                 *mlp = ml->next;
3561                                 dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
3562                                 if (dev)
3563                                         packet_dev_mc(dev, ml, -1);
3564                                 kfree(ml);
3565                         }
3566                         break;
3567                 }
3568         }
3569         rtnl_unlock();
3570         return 0;
3571 }
3572 
3573 static void packet_flush_mclist(struct sock *sk)
3574 {
3575         struct packet_sock *po = pkt_sk(sk);
3576         struct packet_mclist *ml;
3577 
3578         if (!po->mclist)
3579                 return;
3580 
3581         rtnl_lock();
3582         while ((ml = po->mclist) != NULL) {
3583                 struct net_device *dev;
3584 
3585                 po->mclist = ml->next;
3586                 dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
3587                 if (dev != NULL)
3588                         packet_dev_mc(dev, ml, -1);
3589                 kfree(ml);
3590         }
3591         rtnl_unlock();
3592 }
3593 
3594 static int
3595 packet_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
3596 {
3597         struct sock *sk = sock->sk;
3598         struct packet_sock *po = pkt_sk(sk);
3599         int ret;
3600 
3601         if (level != SOL_PACKET)
3602                 return -ENOPROTOOPT;
3603 
3604         switch (optname) {
3605         case PACKET_ADD_MEMBERSHIP:
3606         case PACKET_DROP_MEMBERSHIP:
3607         {
3608                 struct packet_mreq_max mreq;
3609                 int len = optlen;
3610                 memset(&mreq, 0, sizeof(mreq));
3611                 if (len < sizeof(struct packet_mreq))
3612                         return -EINVAL;
3613                 if (len > sizeof(mreq))
3614                         len = sizeof(mreq);
3615                 if (copy_from_user(&mreq, optval, len))
3616                         return -EFAULT;
3617                 if (len < (mreq.mr_alen + offsetof(struct packet_mreq, mr_address)))
3618                         return -EINVAL;
3619                 if (optname == PACKET_ADD_MEMBERSHIP)
3620                         ret = packet_mc_add(sk, &mreq);
3621                 else
3622                         ret = packet_mc_drop(sk, &mreq);
3623                 return ret;
3624         }
3625 
3626         case PACKET_RX_RING:
3627         case PACKET_TX_RING:
3628         {
3629                 union tpacket_req_u req_u;
3630                 int len;
3631 
3632                 lock_sock(sk);
3633                 switch (po->tp_version) {
3634                 case TPACKET_V1:
3635                 case TPACKET_V2:
3636                         len = sizeof(req_u.req);
3637                         break;
3638                 case TPACKET_V3:
3639                 default:
3640                         len = sizeof(req_u.req3);
3641                         break;
3642                 }
3643                 if (optlen < len) {
3644                         ret = -EINVAL;
3645                 } else {
3646                         if (copy_from_user(&req_u.req, optval, len))
3647                                 ret = -EFAULT;
3648                         else
3649                                 ret = packet_set_ring(sk, &req_u, 0,
3650                                                     optname == PACKET_TX_RING);
3651                 }
3652                 release_sock(sk);
3653                 return ret;
3654         }
3655         case PACKET_COPY_THRESH:
3656         {
3657                 int val;
3658 
3659                 if (optlen != sizeof(val))
3660                         return -EINVAL;
3661                 if (copy_from_user(&val, optval, sizeof(val)))
3662                         return -EFAULT;
3663 
3664                 pkt_sk(sk)->copy_thresh = val;
3665                 return 0;
3666         }
3667         case PACKET_VERSION:
3668         {
3669                 int val;
3670 
3671                 if (optlen != sizeof(val))
3672                         return -EINVAL;
3673                 if (copy_from_user(&val, optval, sizeof(val)))
3674                         return -EFAULT;
3675                 switch (val) {
3676                 case TPACKET_V1:
3677                 case TPACKET_V2:
3678                 case TPACKET_V3:
3679                         break;
3680                 default:
3681                         return -EINVAL;
3682                 }
3683                 lock_sock(sk);
3684                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
3685                         ret = -EBUSY;
3686                 } else {
3687                         po->tp_version = val;
3688                         ret = 0;
3689                 }
3690                 release_sock(sk);
3691                 return ret;
3692         }
3693         case PACKET_RESERVE:
3694         {
3695                 unsigned int val;
3696 
3697                 if (optlen != sizeof(val))
3698                         return -EINVAL;
3699                 if (copy_from_user(&val, optval, sizeof(val)))
3700                         return -EFAULT;
3701                 if (val > INT_MAX)
3702                         return -EINVAL;
3703                 lock_sock(sk);
3704                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
3705                         ret = -EBUSY;
3706                 } else {
3707                         po->tp_reserve = val;
3708                         ret = 0;
3709                 }
3710                 release_sock(sk);
3711                 return ret;
3712         }
3713         case PACKET_LOSS:
3714         {
3715                 unsigned int val;
3716 
3717                 if (optlen != sizeof(val))
3718                         return -EINVAL;
3719                 if (copy_from_user(&val, optval, sizeof(val)))
3720                         return -EFAULT;
3721 
3722                 lock_sock(sk);
3723                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
3724                         ret = -EBUSY;
3725                 } else {
3726                         po->tp_loss = !!val;
3727                         ret = 0;
3728                 }
3729                 release_sock(sk);
3730                 return ret;
3731         }
3732         case PACKET_AUXDATA:
3733         {
3734                 int val;
3735 
3736                 if (optlen < sizeof(val))
3737                         return -EINVAL;
3738                 if (copy_from_user(&val, optval, sizeof(val)))
3739                         return -EFAULT;
3740 
3741                 lock_sock(sk);
3742                 po->auxdata = !!val;
3743                 release_sock(sk);
3744                 return 0;
3745         }
3746         case PACKET_ORIGDEV:
3747         {
3748                 int val;
3749 
3750                 if (optlen < sizeof(val))
3751                         return -EINVAL;
3752                 if (copy_from_user(&val, optval, sizeof(val)))
3753                         return -EFAULT;
3754 
3755                 lock_sock(sk);
3756                 po->origdev = !!val;
3757                 release_sock(sk);
3758                 return 0;
3759         }
3760         case PACKET_VNET_HDR:
3761         {
3762                 int val;
3763 
3764                 if (sock->type != SOCK_RAW)
3765                         return -EINVAL;
3766                 if (optlen < sizeof(val))
3767                         return -EINVAL;
3768                 if (copy_from_user(&val, optval, sizeof(val)))
3769                         return -EFAULT;
3770 
3771                 lock_sock(sk);
3772                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
3773                         ret = -EBUSY;
3774                 } else {
3775                         po->has_vnet_hdr = !!val;
3776                         ret = 0;
3777                 }
3778                 release_sock(sk);
3779                 return ret;
3780         }
3781         case PACKET_TIMESTAMP:
3782         {
3783                 int val;
3784 
3785                 if (optlen != sizeof(val))
3786                         return -EINVAL;
3787                 if (copy_from_user(&val, optval, sizeof(val)))
3788                         return -EFAULT;
3789 
3790                 po->tp_tstamp = val;
3791                 return 0;
3792         }
3793         case PACKET_FANOUT:
3794         {
3795                 int val;
3796 
3797                 if (optlen != sizeof(val))
3798                         return -EINVAL;
3799                 if (copy_from_user(&val, optval, sizeof(val)))
3800                         return -EFAULT;
3801 
3802                 return fanout_add(sk, val & 0xffff, val >> 16);
3803         }
3804         case PACKET_FANOUT_DATA:
3805         {
3806                 if (!po->fanout)
3807                         return -EINVAL;
3808 
3809                 return fanout_set_data(po, optval, optlen);
3810         }
3811         case PACKET_IGNORE_OUTGOING:
3812         {
3813                 int val;
3814 
3815                 if (optlen != sizeof(val))
3816                         return -EINVAL;
3817                 if (copy_from_user(&val, optval, sizeof(val)))
3818                         return -EFAULT;
3819                 if (val < 0 || val > 1)
3820                         return -EINVAL;
3821 
3822                 po->prot_hook.ignore_outgoing = !!val;
3823                 return 0;
3824         }
3825         case PACKET_TX_HAS_OFF:
3826         {
3827                 unsigned int val;
3828 
3829                 if (optlen != sizeof(val))
3830                         return -EINVAL;
3831                 if (copy_from_user(&val, optval, sizeof(val)))
3832                         return -EFAULT;
3833 
3834                 lock_sock(sk);
3835                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
3836                         ret = -EBUSY;
3837                 } else {
3838                         po->tp_tx_has_off = !!val;
3839                         ret = 0;
3840                 }
3841                 release_sock(sk);
3842                 return 0;
3843         }
3844         case PACKET_QDISC_BYPASS:
3845         {
3846                 int val;
3847 
3848                 if (optlen != sizeof(val))
3849                         return -EINVAL;
3850                 if (copy_from_user(&val, optval, sizeof(val)))
3851                         return -EFAULT;
3852 
3853                 po->xmit = val ? packet_direct_xmit : dev_queue_xmit;
3854                 return 0;
3855         }
3856         default:
3857                 return -ENOPROTOOPT;
3858         }
3859 }
3860 
3861 static int packet_getsockopt(struct socket *sock, int level, int optname,
3862                              char __user *optval, int __user *optlen)
3863 {
3864         int len;
3865         int val, lv = sizeof(val);
3866         struct sock *sk = sock->sk;
3867         struct packet_sock *po = pkt_sk(sk);
3868         void *data = &val;
3869         union tpacket_stats_u st;
3870         struct tpacket_rollover_stats rstats;
3871 
3872         if (level != SOL_PACKET)
3873                 return -ENOPROTOOPT;
3874 
3875         if (get_user(len, optlen))
3876                 return -EFAULT;
3877 
3878         if (len < 0)
3879                 return -EINVAL;
3880 
3881         switch (optname) {
3882         case PACKET_STATISTICS:
3883                 spin_lock_bh(&sk->sk_receive_queue.lock);
3884                 memcpy(&st, &po->stats, sizeof(st));
3885                 memset(&po->stats, 0, sizeof(po->stats));
3886                 spin_unlock_bh(&sk->sk_receive_queue.lock);
3887 
3888                 if (po->tp_version == TPACKET_V3) {
3889                         lv = sizeof(struct tpacket_stats_v3);
3890                         st.stats3.tp_packets += st.stats3.tp_drops;
3891                         data = &st.stats3;
3892                 } else {
3893                         lv = sizeof(struct tpacket_stats);
3894                         st.stats1.tp_packets += st.stats1.tp_drops;
3895                         data = &st.stats1;
3896                 }
3897 
3898                 break;
3899         case PACKET_AUXDATA:
3900                 val = po->auxdata;
3901                 break;
3902         case PACKET_ORIGDEV:
3903                 val = po->origdev;
3904                 break;
3905         case PACKET_VNET_HDR:
3906                 val = po->has_vnet_hdr;
3907                 break;
3908         case PACKET_VERSION:
3909                 val = po->tp_version;
3910                 break;
3911         case PACKET_HDRLEN:
3912                 if (len > sizeof(int))
3913                         len = sizeof(int);
3914                 if (len < sizeof(int))
3915                         return -EINVAL;
3916                 if (copy_from_user(&val, optval, len))
3917                         return -EFAULT;
3918                 switch (val) {
3919                 case TPACKET_V1:
3920                         val = sizeof(struct tpacket_hdr);
3921                         break;
3922                 case TPACKET_V2:
3923                         val = sizeof(struct tpacket2_hdr);
3924                         break;
3925                 case TPACKET_V3:
3926                         val = sizeof(struct tpacket3_hdr);
3927                         break;
3928                 default:
3929                         return -EINVAL;
3930                 }
3931                 break;
3932         case PACKET_RESERVE:
3933                 val = po->tp_reserve;
3934                 break;
3935         case PACKET_LOSS:
3936                 val = po->tp_loss;
3937                 break;
3938         case PACKET_TIMESTAMP:
3939                 val = po->tp_tstamp;
3940                 break;
3941         case PACKET_FANOUT:
3942                 val = (po->fanout ?
3943                        ((u32)po->fanout->id |
3944                         ((u32)po->fanout->type << 16) |
3945                         ((u32)po->fanout->flags << 24)) :
3946                        0);
3947                 break;
3948         case PACKET_IGNORE_OUTGOING:
3949                 val = po->prot_hook.ignore_outgoing;
3950                 break;
3951         case PACKET_ROLLOVER_STATS:
3952                 if (!po->rollover)
3953                         return -EINVAL;
3954                 rstats.tp_all = atomic_long_read(&po->rollover->num);
3955                 rstats.tp_huge = atomic_long_read(&po->rollover->num_huge);
3956                 rstats.tp_failed = atomic_long_read(&po->rollover->num_failed);
3957                 data = &rstats;
3958                 lv = sizeof(rstats);
3959                 break;
3960         case PACKET_TX_HAS_OFF:
3961                 val = po->tp_tx_has_off;
3962                 break;
3963         case PACKET_QDISC_BYPASS:
3964                 val = packet_use_direct_xmit(po);
3965                 break;
3966         default:
3967                 return -ENOPROTOOPT;
3968         }
3969 
3970         if (len > lv)
3971                 len = lv;
3972         if (put_user(len, optlen))
3973                 return -EFAULT;
3974         if (copy_to_user(optval, data, len))
3975                 return -EFAULT;
3976         return 0;
3977 }
3978 
3979 
3980 #ifdef CONFIG_COMPAT
3981 static int compat_packet_setsockopt(struct socket *sock, int level, int optname,
3982                                     char __user *optval, unsigned int optlen)
3983 {
3984         struct packet_sock *po = pkt_sk(sock->sk);
3985 
3986         if (level != SOL_PACKET)
3987                 return -ENOPROTOOPT;
3988 
3989         if (optname == PACKET_FANOUT_DATA &&
3990             po->fanout && po->fanout->type == PACKET_FANOUT_CBPF) {
3991                 optval = (char __user *)get_compat_bpf_fprog(optval);
3992                 if (!optval)
3993                         return -EFAULT;
3994                 optlen = sizeof(struct sock_fprog);
3995         }
3996 
3997         return packet_setsockopt(sock, level, optname, optval, optlen);
3998 }
3999 #endif
4000 
4001 static int packet_notifier(struct notifier_block *this,
4002                            unsigned long msg, void *ptr)
4003 {
4004         struct sock *sk;
4005         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
4006         struct net *net = dev_net(dev);
4007 
4008         rcu_read_lock();
4009         sk_for_each_rcu(sk, &net->packet.sklist) {
4010                 struct packet_sock *po = pkt_sk(sk);
4011 
4012                 switch (msg) {
4013                 case NETDEV_UNREGISTER:
4014                         if (po->mclist)
4015                                 packet_dev_mclist_delete(dev, &po->mclist);
4016                         /* fallthrough */
4017 
4018                 case NETDEV_DOWN:
4019                         if (dev->ifindex == po->ifindex) {
4020                                 spin_lock(&po->bind_lock);
4021                                 if (po->running) {
4022                                         __unregister_prot_hook(sk, false);
4023                                         sk->sk_err = ENETDOWN;
4024                                         if (!sock_flag(sk, SOCK_DEAD))
4025                                                 sk->sk_error_report(sk);
4026                                 }
4027                                 if (msg == NETDEV_UNREGISTER) {
4028                                         packet_cached_dev_reset(po);
4029                                         po->ifindex = -1;
4030                                         if (po->prot_hook.dev)
4031                                                 dev_put(po->prot_hook.dev);
4032                                         po->prot_hook.dev = NULL;
4033                                 }
4034                                 spin_unlock(&po->bind_lock);
4035                         }
4036                         break;
4037                 case NETDEV_UP:
4038                         if (dev->ifindex == po->ifindex) {
4039                                 spin_lock(&po->bind_lock);
4040                                 if (po->num)
4041                                         register_prot_hook(sk);
4042                                 spin_unlock(&po->bind_lock);
4043                         }
4044                         break;
4045                 }
4046         }
4047         rcu_read_unlock();
4048         return NOTIFY_DONE;
4049 }
4050 
4051 
4052 static int packet_ioctl(struct socket *sock, unsigned int cmd,
4053                         unsigned long arg)
4054 {
4055         struct sock *sk = sock->sk;
4056 
4057         switch (cmd) {
4058         case SIOCOUTQ:
4059         {
4060                 int amount = sk_wmem_alloc_get(sk);
4061 
4062                 return put_user(amount, (int __user *)arg);
4063         }
4064         case SIOCINQ:
4065         {
4066                 struct sk_buff *skb;
4067                 int amount = 0;
4068 
4069                 spin_lock_bh(&sk->sk_receive_queue.lock);
4070                 skb = skb_peek(&sk->sk_receive_queue);
4071                 if (skb)
4072                         amount = skb->len;
4073                 spin_unlock_bh(&sk->sk_receive_queue.lock);
4074                 return put_user(amount, (int __user *)arg);
4075         }
4076         case SIOCGSTAMP:
4077                 return sock_get_timestamp(sk, (struct timeval __user *)arg);
4078         case SIOCGSTAMPNS:
4079                 return sock_get_timestampns(sk, (struct timespec __user *)arg);
4080 
4081 #ifdef CONFIG_INET
4082         case SIOCADDRT:
4083         case SIOCDELRT:
4084         case SIOCDARP:
4085         case SIOCGARP:
4086         case SIOCSARP:
4087         case SIOCGIFADDR:
4088         case SIOCSIFADDR:
4089         case SIOCGIFBRDADDR:
4090         case SIOCSIFBRDADDR:
4091         case SIOCGIFNETMASK:
4092         case SIOCSIFNETMASK:
4093         case SIOCGIFDSTADDR:
4094         case SIOCSIFDSTADDR:
4095         case SIOCSIFFLAGS:
4096                 return inet_dgram_ops.ioctl(sock, cmd, arg);
4097 #endif
4098 
4099         default:
4100                 return -ENOIOCTLCMD;
4101         }
4102         return 0;
4103 }
4104 
4105 static __poll_t packet_poll(struct file *file, struct socket *sock,
4106                                 poll_table *wait)
4107 {
4108         struct sock *sk = sock->sk;
4109         struct packet_sock *po = pkt_sk(sk);
4110         __poll_t mask = datagram_poll(file, sock, wait);
4111 
4112         spin_lock_bh(&sk->sk_receive_queue.lock);
4113         if (po->rx_ring.pg_vec) {
4114                 if (!packet_previous_rx_frame(po, &po->rx_ring,
4115                         TP_STATUS_KERNEL))
4116                         mask |= EPOLLIN | EPOLLRDNORM;
4117         }
4118         if (po->pressure && __packet_rcv_has_room(po, NULL) == ROOM_NORMAL)
4119                 po->pressure = 0;
4120         spin_unlock_bh(&sk->sk_receive_queue.lock);
4121         spin_lock_bh(&sk->sk_write_queue.lock);
4122         if (po->tx_ring.pg_vec) {
4123                 if (packet_current_frame(po, &po->tx_ring, TP_STATUS_AVAILABLE))
4124                         mask |= EPOLLOUT | EPOLLWRNORM;
4125         }
4126         spin_unlock_bh(&sk->sk_write_queue.lock);
4127         return mask;
4128 }
4129 
4130 
4131 /* Dirty? Well, I still did not learn better way to account
4132  * for user mmaps.
4133  */
4134 
4135 static void packet_mm_open(struct vm_area_struct *vma)
4136 {
4137         struct file *file = vma->vm_file;
4138         struct socket *sock = file->private_data;
4139         struct sock *sk = sock->sk;
4140 
4141         if (sk)
4142                 atomic_inc(&pkt_sk(sk)->mapped);
4143 }
4144 
4145 static void packet_mm_close(struct vm_area_struct *vma)
4146 {
4147         struct file *file = vma->vm_file;
4148         struct socket *sock = file->private_data;
4149         struct sock *sk = sock->sk;
4150 
4151         if (sk)
4152                 atomic_dec(&pkt_sk(sk)->mapped);
4153 }
4154 
4155 static const struct vm_operations_struct packet_mmap_ops = {
4156         .open   =       packet_mm_open,
4157         .close  =       packet_mm_close,
4158 };
4159 
4160 static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
4161                         unsigned int len)
4162 {
4163         int i;
4164 
4165         for (i = 0; i < len; i++) {
4166                 if (likely(pg_vec[i].buffer)) {
4167                         if (is_vmalloc_addr(pg_vec[i].buffer))
4168                                 vfree(pg_vec[i].buffer);
4169                         else
4170                                 free_pages((unsigned long)pg_vec[i].buffer,
4171                                            order);
4172                         pg_vec[i].buffer = NULL;
4173                 }
4174         }
4175         kfree(pg_vec);
4176 }
4177 
4178 static char *alloc_one_pg_vec_page(unsigned long order)
4179 {
4180         char *buffer;
4181         gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
4182                           __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
4183 
4184         buffer = (char *) __get_free_pages(gfp_flags, order);
4185         if (buffer)
4186                 return buffer;
4187 
4188         /* __get_free_pages failed, fall back to vmalloc */
4189         buffer = vzalloc(array_size((1 << order), PAGE_SIZE));
4190         if (buffer)
4191                 return buffer;
4192 
4193         /* vmalloc failed, lets dig into swap here */
4194         gfp_flags &= ~__GFP_NORETRY;
4195         buffer = (char *) __get_free_pages(gfp_flags, order);
4196         if (buffer)
4197                 return buffer;
4198 
4199         /* complete and utter failure */
4200         return NULL;
4201 }
4202 
4203 static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
4204 {
4205         unsigned int block_nr = req->tp_block_nr;
4206         struct pgv *pg_vec;
4207         int i;
4208 
4209         pg_vec = kcalloc(block_nr, sizeof(struct pgv), GFP_KERNEL);
4210         if (unlikely(!pg_vec))
4211                 goto out;
4212 
4213         for (i = 0; i < block_nr; i++) {
4214                 pg_vec[i].buffer = alloc_one_pg_vec_page(order);
4215                 if (unlikely(!pg_vec[i].buffer))
4216                         goto out_free_pgvec;
4217         }
4218 
4219 out:
4220         return pg_vec;
4221 
4222 out_free_pgvec:
4223         free_pg_vec(pg_vec, order, block_nr);
4224         pg_vec = NULL;
4225         goto out;
4226 }
4227 
4228 static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
4229                 int closing, int tx_ring)
4230 {
4231         struct pgv *pg_vec = NULL;
4232         struct packet_sock *po = pkt_sk(sk);
4233         int was_running, order = 0;
4234         struct packet_ring_buffer *rb;
4235         struct sk_buff_head *rb_queue;
4236         __be16 num;
4237         int err = -EINVAL;
4238         /* Added to avoid minimal code churn */
4239         struct tpacket_req *req = &req_u->req;
4240 
4241         rb = tx_ring ? &po->tx_ring : &po->rx_ring;
4242         rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
4243 
4244         err = -EBUSY;
4245         if (!closing) {
4246                 if (atomic_read(&po->mapped))
4247                         goto out;
4248                 if (packet_read_pending(rb))
4249                         goto out;
4250         }
4251 
4252         if (req->tp_block_nr) {
4253                 unsigned int min_frame_size;
4254 
4255                 /* Sanity tests and some calculations */
4256                 err = -EBUSY;
4257                 if (unlikely(rb->pg_vec))
4258                         goto out;
4259 
4260                 switch (po->tp_version) {
4261                 case TPACKET_V1:
4262                         po->tp_hdrlen = TPACKET_HDRLEN;
4263                         break;
4264                 case TPACKET_V2:
4265                         po->tp_hdrlen = TPACKET2_HDRLEN;
4266                         break;
4267                 case TPACKET_V3:
4268                         po->tp_hdrlen = TPACKET3_HDRLEN;
4269                         break;
4270                 }
4271 
4272                 err = -EINVAL;
4273                 if (unlikely((int)req->tp_block_size <= 0))
4274                         goto out;
4275                 if (unlikely(!PAGE_ALIGNED(req->tp_block_size)))
4276                         goto out;
4277                 min_frame_size = po->tp_hdrlen + po->tp_reserve;
4278                 if (po->tp_version >= TPACKET_V3 &&
4279                     req->tp_block_size <
4280                     BLK_PLUS_PRIV((u64)req_u->req3.tp_sizeof_priv) + min_frame_size)
4281                         goto out;
4282                 if (unlikely(req->tp_frame_size < min_frame_size))
4283                         goto out;
4284                 if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
4285                         goto out;
4286 
4287                 rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
4288                 if (unlikely(rb->frames_per_block == 0))
4289                         goto out;
4290                 if (unlikely(req->tp_block_size > UINT_MAX / req->tp_block_nr))
4291                         goto out;
4292                 if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
4293                                         req->tp_frame_nr))
4294                         goto out;
4295 
4296                 err = -ENOMEM;
4297                 order = get_order(req->tp_block_size);
4298                 pg_vec = alloc_pg_vec(req, order);
4299                 if (unlikely(!pg_vec))
4300                         goto out;
4301                 switch (po->tp_version) {
4302                 case TPACKET_V3:
4303                         /* Block transmit is not supported yet */
4304                         if (!tx_ring) {
4305                                 init_prb_bdqc(po, rb, pg_vec, req_u);
4306                         } else {
4307                                 struct tpacket_req3 *req3 = &req_u->req3;
4308 
4309                                 if (req3->tp_retire_blk_tov ||
4310                                     req3->tp_sizeof_priv ||
4311                                     req3->tp_feature_req_word) {
4312                                         err = -EINVAL;
4313                                         goto out;
4314                                 }
4315                         }
4316                         break;
4317                 default:
4318                         break;
4319                 }
4320         }
4321         /* Done */
4322         else {
4323                 err = -EINVAL;
4324                 if (unlikely(req->tp_frame_nr))
4325                         goto out;
4326         }
4327 
4328 
4329         /* Detach socket from network */
4330         spin_lock(&po->bind_lock);
4331         was_running = po->running;
4332         num = po->num;
4333         if (was_running) {
4334                 po->num = 0;
4335                 __unregister_prot_hook(sk, false);
4336         }
4337         spin_unlock(&po->bind_lock);
4338 
4339         synchronize_net();
4340 
4341         err = -EBUSY;
4342         mutex_lock(&po->pg_vec_lock);
4343         if (closing || atomic_read(&po->mapped) == 0) {
4344                 err = 0;
4345                 spin_lock_bh(&rb_queue->lock);
4346                 swap(rb->pg_vec, pg_vec);
4347                 rb->frame_max = (req->tp_frame_nr - 1);
4348                 rb->head = 0;
4349                 rb->frame_size = req->tp_frame_size;
4350                 spin_unlock_bh(&rb_queue->lock);
4351 
4352                 swap(rb->pg_vec_order, order);
4353                 swap(rb->pg_vec_len, req->tp_block_nr);
4354 
4355                 rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
4356                 po->prot_hook.func = (po->rx_ring.pg_vec) ?
4357                                                 tpacket_rcv : packet_rcv;
4358                 skb_queue_purge(rb_queue);
4359                 if (atomic_read(&po->mapped))
4360                         pr_err("packet_mmap: vma is busy: %d\n",
4361                                atomic_read(&po->mapped));
4362         }
4363         mutex_unlock(&po->pg_vec_lock);
4364 
4365         spin_lock(&po->bind_lock);
4366         if (was_running) {
4367                 po->num = num;
4368                 register_prot_hook(sk);
4369         }
4370         spin_unlock(&po->bind_lock);
4371         if (pg_vec && (po->tp_version > TPACKET_V2)) {
4372                 /* Because we don't support block-based V3 on tx-ring */
4373                 if (!tx_ring)
4374                         prb_shutdown_retire_blk_timer(po, rb_queue);
4375         }
4376 
4377         if (pg_vec)
4378                 free_pg_vec(pg_vec, order, req->tp_block_nr);
4379 out:
4380         return err;
4381 }
4382 
4383 static int packet_mmap(struct file *file, struct socket *sock,
4384                 struct vm_area_struct *vma)
4385 {
4386         struct sock *sk = sock->sk;
4387         struct packet_sock *po = pkt_sk(sk);
4388         unsigned long size, expected_size;
4389         struct packet_ring_buffer *rb;
4390         unsigned long start;
4391         int err = -EINVAL;
4392         int i;
4393 
4394         if (vma->vm_pgoff)
4395                 return -EINVAL;
4396 
4397         mutex_lock(&po->pg_vec_lock);
4398 
4399         expected_size = 0;
4400         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
4401                 if (rb->pg_vec) {
4402                         expected_size += rb->pg_vec_len
4403                                                 * rb->pg_vec_pages
4404                                                 * PAGE_SIZE;
4405                 }
4406         }
4407 
4408         if (expected_size == 0)
4409                 goto out;
4410 
4411         size = vma->vm_end - vma->vm_start;
4412         if (size != expected_size)
4413                 goto out;
4414 
4415         start = vma->vm_start;
4416         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
4417                 if (rb->pg_vec == NULL)
4418                         continue;
4419 
4420                 for (i = 0; i < rb->pg_vec_len; i++) {
4421                         struct page *page;
4422                         void *kaddr = rb->pg_vec[i].buffer;
4423                         int pg_num;
4424 
4425                         for (pg_num = 0; pg_num < rb->pg_vec_pages; pg_num++) {
4426                                 page = pgv_to_page(kaddr);
4427                                 err = vm_insert_page(vma, start, page);
4428                                 if (unlikely(err))
4429                                         goto out;
4430                                 start += PAGE_SIZE;
4431                                 kaddr += PAGE_SIZE;
4432                         }
4433                 }
4434         }
4435 
4436         atomic_inc(&po->mapped);
4437         vma->vm_ops = &packet_mmap_ops;
4438         err = 0;
4439 
4440 out:
4441         mutex_unlock(&po->pg_vec_lock);
4442         return err;
4443 }
4444 
4445 static const struct proto_ops packet_ops_spkt = {
4446         .family =       PF_PACKET,
4447         .owner =        THIS_MODULE,
4448         .release =      packet_release,
4449         .bind =         packet_bind_spkt,
4450         .connect =      sock_no_connect,
4451         .socketpair =   sock_no_socketpair,
4452         .accept =       sock_no_accept,
4453         .getname =      packet_getname_spkt,
4454         .poll =         datagram_poll,
4455         .ioctl =        packet_ioctl,
4456         .listen =       sock_no_listen,
4457         .shutdown =     sock_no_shutdown,
4458         .setsockopt =   sock_no_setsockopt,
4459         .getsockopt =   sock_no_getsockopt,
4460         .sendmsg =      packet_sendmsg_spkt,
4461         .recvmsg =      packet_recvmsg,
4462         .mmap =         sock_no_mmap,
4463         .sendpage =     sock_no_sendpage,
4464 };
4465 
4466 static const struct proto_ops packet_ops = {
4467         .family =       PF_PACKET,
4468         .owner =        THIS_MODULE,
4469         .release =      packet_release,
4470         .bind =         packet_bind,
4471         .connect =      sock_no_connect,
4472         .socketpair =   sock_no_socketpair,
4473         .accept =       sock_no_accept,
4474         .getname =      packet_getname,
4475         .poll =         packet_poll,
4476         .ioctl =        packet_ioctl,
4477         .listen =       sock_no_listen,
4478         .shutdown =     sock_no_shutdown,
4479         .setsockopt =   packet_setsockopt,
4480         .getsockopt =   packet_getsockopt,
4481 #ifdef CONFIG_COMPAT
4482         .compat_setsockopt = compat_packet_setsockopt,
4483 #endif
4484         .sendmsg =      packet_sendmsg,
4485         .recvmsg =      packet_recvmsg,
4486         .mmap =         packet_mmap,
4487         .sendpage =     sock_no_sendpage,
4488 };
4489 
4490 static const struct net_proto_family packet_family_ops = {
4491         .family =       PF_PACKET,
4492         .create =       packet_create,
4493         .owner  =       THIS_MODULE,
4494 };
4495 
4496 static struct notifier_block packet_netdev_notifier = {
4497         .notifier_call =        packet_notifier,
4498 };
4499 
4500 #ifdef CONFIG_PROC_FS
4501 
4502 static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
4503         __acquires(RCU)
4504 {
4505         struct net *net = seq_file_net(seq);
4506 
4507         rcu_read_lock();
4508         return seq_hlist_start_head_rcu(&net->packet.sklist, *pos);
4509 }
4510 
4511 static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
4512 {
4513         struct net *net = seq_file_net(seq);
4514         return seq_hlist_next_rcu(v, &net->packet.sklist, pos);
4515 }
4516 
4517 static void packet_seq_stop(struct seq_file *seq, void *v)
4518         __releases(RCU)
4519 {
4520         rcu_read_unlock();
4521 }
4522 
4523 static int packet_seq_show(struct seq_file *seq, void *v)
4524 {
4525         if (v == SEQ_START_TOKEN)
4526                 seq_puts(seq, "sk       RefCnt Type Proto  Iface R Rmem   User   Inode\n");
4527         else {
4528                 struct sock *s = sk_entry(v);
4529                 const struct packet_sock *po = pkt_sk(s);
4530 
4531                 seq_printf(seq,
4532                            "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
4533                            s,
4534                            refcount_read(&s->sk_refcnt),
4535                            s->sk_type,
4536                            ntohs(po->num),
4537                            po->ifindex,
4538                            po->running,
4539                            atomic_read(&s->sk_rmem_alloc),
4540                            from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
4541                            sock_i_ino(s));
4542         }
4543 
4544         return 0;
4545 }
4546 
4547 static const struct seq_operations packet_seq_ops = {
4548         .start  = packet_seq_start,
4549         .next   = packet_seq_next,
4550         .stop   = packet_seq_stop,
4551         .show   = packet_seq_show,
4552 };
4553 #endif
4554 
4555 static int __net_init packet_net_init(struct net *net)
4556 {
4557         mutex_init(&net->packet.sklist_lock);
4558         INIT_HLIST_HEAD(&net->packet.sklist);
4559 
4560         if (!proc_create_net("packet", 0, net->proc_net, &packet_seq_ops,
4561                         sizeof(struct seq_net_private)))
4562                 return -ENOMEM;
4563 
4564         return 0;
4565 }
4566 
4567 static void __net_exit packet_net_exit(struct net *net)
4568 {
4569         remove_proc_entry("packet", net->proc_net);
4570         WARN_ON_ONCE(!hlist_empty(&net->packet.sklist));
4571 }
4572 
4573 static struct pernet_operations packet_net_ops = {
4574         .init = packet_net_init,
4575         .exit = packet_net_exit,
4576 };
4577 
4578 
4579 static void __exit packet_exit(void)
4580 {
4581         unregister_netdevice_notifier(&packet_netdev_notifier);
4582         unregister_pernet_subsys(&packet_net_ops);
4583         sock_unregister(PF_PACKET);
4584         proto_unregister(&packet_proto);
4585 }
4586 
4587 static int __init packet_init(void)
4588 {
4589         int rc = proto_register(&packet_proto, 0);
4590 
4591         if (rc != 0)
4592                 goto out;
4593 
4594         sock_register(&packet_family_ops);
4595         register_pernet_subsys(&packet_net_ops);
4596         register_netdevice_notifier(&packet_netdev_notifier);
4597 out:
4598         return rc;
4599 }
4600 
4601 module_init(packet_init);
4602 module_exit(packet_exit);
4603 MODULE_LICENSE("GPL");
4604 MODULE_ALIAS_NETPROTO(PF_PACKET);
4605 

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