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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 <asm/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 
 92 #ifdef CONFIG_INET
 93 #include <net/inet_common.h>
 94 #endif
 95 
 96 #include "internal.h"
 97 
 98 /*
 99    Assumptions:
100    - if device has no dev->hard_header routine, it adds and removes ll header
101      inside itself. In this case ll header is invisible outside of device,
102      but higher levels still should reserve dev->hard_header_len.
103      Some devices are enough clever to reallocate skb, when header
104      will not fit to reserved space (tunnel), another ones are silly
105      (PPP).
106    - packet socket receives packets with pulled ll header,
107      so that SOCK_RAW should push it back.
108 
109 On receive:
110 -----------
111 
112 Incoming, dev->hard_header!=NULL
113    mac_header -> ll header
114    data       -> data
115 
116 Outgoing, dev->hard_header!=NULL
117    mac_header -> ll header
118    data       -> ll header
119 
120 Incoming, dev->hard_header==NULL
121    mac_header -> UNKNOWN position. It is very likely, that it points to ll
122                  header.  PPP makes it, that is wrong, because introduce
123                  assymetry between rx and tx paths.
124    data       -> data
125 
126 Outgoing, dev->hard_header==NULL
127    mac_header -> data. ll header is still not built!
128    data       -> data
129 
130 Resume
131   If dev->hard_header==NULL we are unlikely to restore sensible ll header.
132 
133 
134 On transmit:
135 ------------
136 
137 dev->hard_header != NULL
138    mac_header -> ll header
139    data       -> ll header
140 
141 dev->hard_header == NULL (ll header is added by device, we cannot control it)
142    mac_header -> data
143    data       -> data
144 
145    We should set nh.raw on output to correct posistion,
146    packet classifier depends on it.
147  */
148 
149 /* Private packet socket structures. */
150 
151 /* identical to struct packet_mreq except it has
152  * a longer address field.
153  */
154 struct packet_mreq_max {
155         int             mr_ifindex;
156         unsigned short  mr_type;
157         unsigned short  mr_alen;
158         unsigned char   mr_address[MAX_ADDR_LEN];
159 };
160 
161 union tpacket_uhdr {
162         struct tpacket_hdr  *h1;
163         struct tpacket2_hdr *h2;
164         struct tpacket3_hdr *h3;
165         void *raw;
166 };
167 
168 static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
169                 int closing, int tx_ring);
170 
171 #define V3_ALIGNMENT    (8)
172 
173 #define BLK_HDR_LEN     (ALIGN(sizeof(struct tpacket_block_desc), V3_ALIGNMENT))
174 
175 #define BLK_PLUS_PRIV(sz_of_priv) \
176         (BLK_HDR_LEN + ALIGN((sz_of_priv), V3_ALIGNMENT))
177 
178 #define PGV_FROM_VMALLOC 1
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_snd(struct packet_sock *po, struct msghdr *msg);
190 static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
191                        struct packet_type *pt, struct net_device *orig_dev);
192 
193 static void *packet_previous_frame(struct packet_sock *po,
194                 struct packet_ring_buffer *rb,
195                 int status);
196 static void packet_increment_head(struct packet_ring_buffer *buff);
197 static int prb_curr_blk_in_use(struct tpacket_kbdq_core *,
198                         struct tpacket_block_desc *);
199 static void *prb_dispatch_next_block(struct tpacket_kbdq_core *,
200                         struct packet_sock *);
201 static void prb_retire_current_block(struct tpacket_kbdq_core *,
202                 struct packet_sock *, unsigned int status);
203 static int prb_queue_frozen(struct tpacket_kbdq_core *);
204 static void prb_open_block(struct tpacket_kbdq_core *,
205                 struct tpacket_block_desc *);
206 static void prb_retire_rx_blk_timer_expired(unsigned long);
207 static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *);
208 static void prb_init_blk_timer(struct packet_sock *,
209                 struct tpacket_kbdq_core *,
210                 void (*func) (unsigned long));
211 static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *);
212 static void prb_clear_rxhash(struct tpacket_kbdq_core *,
213                 struct tpacket3_hdr *);
214 static void prb_fill_vlan_info(struct tpacket_kbdq_core *,
215                 struct tpacket3_hdr *);
216 static void packet_flush_mclist(struct sock *sk);
217 
218 struct packet_skb_cb {
219         unsigned int origlen;
220         union {
221                 struct sockaddr_pkt pkt;
222                 struct sockaddr_ll ll;
223         } sa;
224 };
225 
226 #define PACKET_SKB_CB(__skb)    ((struct packet_skb_cb *)((__skb)->cb))
227 
228 #define GET_PBDQC_FROM_RB(x)    ((struct tpacket_kbdq_core *)(&(x)->prb_bdqc))
229 #define GET_PBLOCK_DESC(x, bid) \
230         ((struct tpacket_block_desc *)((x)->pkbdq[(bid)].buffer))
231 #define GET_CURR_PBLOCK_DESC_FROM_CORE(x)       \
232         ((struct tpacket_block_desc *)((x)->pkbdq[(x)->kactive_blk_num].buffer))
233 #define GET_NEXT_PRB_BLK_NUM(x) \
234         (((x)->kactive_blk_num < ((x)->knum_blocks-1)) ? \
235         ((x)->kactive_blk_num+1) : 0)
236 
237 static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
238 static void __fanout_link(struct sock *sk, struct packet_sock *po);
239 
240 /* register_prot_hook must be invoked with the po->bind_lock held,
241  * or from a context in which asynchronous accesses to the packet
242  * socket is not possible (packet_create()).
243  */
244 static void register_prot_hook(struct sock *sk)
245 {
246         struct packet_sock *po = pkt_sk(sk);
247         if (!po->running) {
248                 if (po->fanout)
249                         __fanout_link(sk, po);
250                 else
251                         dev_add_pack(&po->prot_hook);
252                 sock_hold(sk);
253                 po->running = 1;
254         }
255 }
256 
257 /* {,__}unregister_prot_hook() must be invoked with the po->bind_lock
258  * held.   If the sync parameter is true, we will temporarily drop
259  * the po->bind_lock and do a synchronize_net to make sure no
260  * asynchronous packet processing paths still refer to the elements
261  * of po->prot_hook.  If the sync parameter is false, it is the
262  * callers responsibility to take care of this.
263  */
264 static void __unregister_prot_hook(struct sock *sk, bool sync)
265 {
266         struct packet_sock *po = pkt_sk(sk);
267 
268         po->running = 0;
269         if (po->fanout)
270                 __fanout_unlink(sk, po);
271         else
272                 __dev_remove_pack(&po->prot_hook);
273         __sock_put(sk);
274 
275         if (sync) {
276                 spin_unlock(&po->bind_lock);
277                 synchronize_net();
278                 spin_lock(&po->bind_lock);
279         }
280 }
281 
282 static void unregister_prot_hook(struct sock *sk, bool sync)
283 {
284         struct packet_sock *po = pkt_sk(sk);
285 
286         if (po->running)
287                 __unregister_prot_hook(sk, sync);
288 }
289 
290 static inline __pure struct page *pgv_to_page(void *addr)
291 {
292         if (is_vmalloc_addr(addr))
293                 return vmalloc_to_page(addr);
294         return virt_to_page(addr);
295 }
296 
297 static void __packet_set_status(struct packet_sock *po, void *frame, int status)
298 {
299         union tpacket_uhdr h;
300 
301         h.raw = frame;
302         switch (po->tp_version) {
303         case TPACKET_V1:
304                 h.h1->tp_status = status;
305                 flush_dcache_page(pgv_to_page(&h.h1->tp_status));
306                 break;
307         case TPACKET_V2:
308                 h.h2->tp_status = status;
309                 flush_dcache_page(pgv_to_page(&h.h2->tp_status));
310                 break;
311         case TPACKET_V3:
312         default:
313                 WARN(1, "TPACKET version not supported.\n");
314                 BUG();
315         }
316 
317         smp_wmb();
318 }
319 
320 static int __packet_get_status(struct packet_sock *po, void *frame)
321 {
322         union tpacket_uhdr h;
323 
324         smp_rmb();
325 
326         h.raw = frame;
327         switch (po->tp_version) {
328         case TPACKET_V1:
329                 flush_dcache_page(pgv_to_page(&h.h1->tp_status));
330                 return h.h1->tp_status;
331         case TPACKET_V2:
332                 flush_dcache_page(pgv_to_page(&h.h2->tp_status));
333                 return h.h2->tp_status;
334         case TPACKET_V3:
335         default:
336                 WARN(1, "TPACKET version not supported.\n");
337                 BUG();
338                 return 0;
339         }
340 }
341 
342 static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec *ts,
343                                    unsigned int flags)
344 {
345         struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
346 
347         if (shhwtstamps) {
348                 if ((flags & SOF_TIMESTAMPING_SYS_HARDWARE) &&
349                     ktime_to_timespec_cond(shhwtstamps->syststamp, ts))
350                         return TP_STATUS_TS_SYS_HARDWARE;
351                 if ((flags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
352                     ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts))
353                         return TP_STATUS_TS_RAW_HARDWARE;
354         }
355 
356         if (ktime_to_timespec_cond(skb->tstamp, ts))
357                 return TP_STATUS_TS_SOFTWARE;
358 
359         return 0;
360 }
361 
362 static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame,
363                                     struct sk_buff *skb)
364 {
365         union tpacket_uhdr h;
366         struct timespec ts;
367         __u32 ts_status;
368 
369         if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
370                 return 0;
371 
372         h.raw = frame;
373         switch (po->tp_version) {
374         case TPACKET_V1:
375                 h.h1->tp_sec = ts.tv_sec;
376                 h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
377                 break;
378         case TPACKET_V2:
379                 h.h2->tp_sec = ts.tv_sec;
380                 h.h2->tp_nsec = ts.tv_nsec;
381                 break;
382         case TPACKET_V3:
383         default:
384                 WARN(1, "TPACKET version not supported.\n");
385                 BUG();
386         }
387 
388         /* one flush is safe, as both fields always lie on the same cacheline */
389         flush_dcache_page(pgv_to_page(&h.h1->tp_sec));
390         smp_wmb();
391 
392         return ts_status;
393 }
394 
395 static void *packet_lookup_frame(struct packet_sock *po,
396                 struct packet_ring_buffer *rb,
397                 unsigned int position,
398                 int status)
399 {
400         unsigned int pg_vec_pos, frame_offset;
401         union tpacket_uhdr h;
402 
403         pg_vec_pos = position / rb->frames_per_block;
404         frame_offset = position % rb->frames_per_block;
405 
406         h.raw = rb->pg_vec[pg_vec_pos].buffer +
407                 (frame_offset * rb->frame_size);
408 
409         if (status != __packet_get_status(po, h.raw))
410                 return NULL;
411 
412         return h.raw;
413 }
414 
415 static void *packet_current_frame(struct packet_sock *po,
416                 struct packet_ring_buffer *rb,
417                 int status)
418 {
419         return packet_lookup_frame(po, rb, rb->head, status);
420 }
421 
422 static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc)
423 {
424         del_timer_sync(&pkc->retire_blk_timer);
425 }
426 
427 static void prb_shutdown_retire_blk_timer(struct packet_sock *po,
428                 int tx_ring,
429                 struct sk_buff_head *rb_queue)
430 {
431         struct tpacket_kbdq_core *pkc;
432 
433         pkc = tx_ring ? &po->tx_ring.prb_bdqc : &po->rx_ring.prb_bdqc;
434 
435         spin_lock(&rb_queue->lock);
436         pkc->delete_blk_timer = 1;
437         spin_unlock(&rb_queue->lock);
438 
439         prb_del_retire_blk_timer(pkc);
440 }
441 
442 static void prb_init_blk_timer(struct packet_sock *po,
443                 struct tpacket_kbdq_core *pkc,
444                 void (*func) (unsigned long))
445 {
446         init_timer(&pkc->retire_blk_timer);
447         pkc->retire_blk_timer.data = (long)po;
448         pkc->retire_blk_timer.function = func;
449         pkc->retire_blk_timer.expires = jiffies;
450 }
451 
452 static void prb_setup_retire_blk_timer(struct packet_sock *po, int tx_ring)
453 {
454         struct tpacket_kbdq_core *pkc;
455 
456         if (tx_ring)
457                 BUG();
458 
459         pkc = tx_ring ? &po->tx_ring.prb_bdqc : &po->rx_ring.prb_bdqc;
460         prb_init_blk_timer(po, pkc, prb_retire_rx_blk_timer_expired);
461 }
462 
463 static int prb_calc_retire_blk_tmo(struct packet_sock *po,
464                                 int blk_size_in_bytes)
465 {
466         struct net_device *dev;
467         unsigned int mbits = 0, msec = 0, div = 0, tmo = 0;
468         struct ethtool_cmd ecmd;
469         int err;
470         u32 speed;
471 
472         rtnl_lock();
473         dev = __dev_get_by_index(sock_net(&po->sk), po->ifindex);
474         if (unlikely(!dev)) {
475                 rtnl_unlock();
476                 return DEFAULT_PRB_RETIRE_TOV;
477         }
478         err = __ethtool_get_settings(dev, &ecmd);
479         speed = ethtool_cmd_speed(&ecmd);
480         rtnl_unlock();
481         if (!err) {
482                 /*
483                  * If the link speed is so slow you don't really
484                  * need to worry about perf anyways
485                  */
486                 if (speed < SPEED_1000 || speed == SPEED_UNKNOWN) {
487                         return DEFAULT_PRB_RETIRE_TOV;
488                 } else {
489                         msec = 1;
490                         div = speed / 1000;
491                 }
492         }
493 
494         mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
495 
496         if (div)
497                 mbits /= div;
498 
499         tmo = mbits * msec;
500 
501         if (div)
502                 return tmo+1;
503         return tmo;
504 }
505 
506 static void prb_init_ft_ops(struct tpacket_kbdq_core *p1,
507                         union tpacket_req_u *req_u)
508 {
509         p1->feature_req_word = req_u->req3.tp_feature_req_word;
510 }
511 
512 static void init_prb_bdqc(struct packet_sock *po,
513                         struct packet_ring_buffer *rb,
514                         struct pgv *pg_vec,
515                         union tpacket_req_u *req_u, int tx_ring)
516 {
517         struct tpacket_kbdq_core *p1 = &rb->prb_bdqc;
518         struct tpacket_block_desc *pbd;
519 
520         memset(p1, 0x0, sizeof(*p1));
521 
522         p1->knxt_seq_num = 1;
523         p1->pkbdq = pg_vec;
524         pbd = (struct tpacket_block_desc *)pg_vec[0].buffer;
525         p1->pkblk_start = pg_vec[0].buffer;
526         p1->kblk_size = req_u->req3.tp_block_size;
527         p1->knum_blocks = req_u->req3.tp_block_nr;
528         p1->hdrlen = po->tp_hdrlen;
529         p1->version = po->tp_version;
530         p1->last_kactive_blk_num = 0;
531         po->stats.stats3.tp_freeze_q_cnt = 0;
532         if (req_u->req3.tp_retire_blk_tov)
533                 p1->retire_blk_tov = req_u->req3.tp_retire_blk_tov;
534         else
535                 p1->retire_blk_tov = prb_calc_retire_blk_tmo(po,
536                                                 req_u->req3.tp_block_size);
537         p1->tov_in_jiffies = msecs_to_jiffies(p1->retire_blk_tov);
538         p1->blk_sizeof_priv = req_u->req3.tp_sizeof_priv;
539 
540         prb_init_ft_ops(p1, req_u);
541         prb_setup_retire_blk_timer(po, tx_ring);
542         prb_open_block(p1, pbd);
543 }
544 
545 /*  Do NOT update the last_blk_num first.
546  *  Assumes sk_buff_head lock is held.
547  */
548 static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc)
549 {
550         mod_timer(&pkc->retire_blk_timer,
551                         jiffies + pkc->tov_in_jiffies);
552         pkc->last_kactive_blk_num = pkc->kactive_blk_num;
553 }
554 
555 /*
556  * Timer logic:
557  * 1) We refresh the timer only when we open a block.
558  *    By doing this we don't waste cycles refreshing the timer
559  *        on packet-by-packet basis.
560  *
561  * With a 1MB block-size, on a 1Gbps line, it will take
562  * i) ~8 ms to fill a block + ii) memcpy etc.
563  * In this cut we are not accounting for the memcpy time.
564  *
565  * So, if the user sets the 'tmo' to 10ms then the timer
566  * will never fire while the block is still getting filled
567  * (which is what we want). However, the user could choose
568  * to close a block early and that's fine.
569  *
570  * But when the timer does fire, we check whether or not to refresh it.
571  * Since the tmo granularity is in msecs, it is not too expensive
572  * to refresh the timer, lets say every '8' msecs.
573  * Either the user can set the 'tmo' or we can derive it based on
574  * a) line-speed and b) block-size.
575  * prb_calc_retire_blk_tmo() calculates the tmo.
576  *
577  */
578 static void prb_retire_rx_blk_timer_expired(unsigned long data)
579 {
580         struct packet_sock *po = (struct packet_sock *)data;
581         struct tpacket_kbdq_core *pkc = &po->rx_ring.prb_bdqc;
582         unsigned int frozen;
583         struct tpacket_block_desc *pbd;
584 
585         spin_lock(&po->sk.sk_receive_queue.lock);
586 
587         frozen = prb_queue_frozen(pkc);
588         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
589 
590         if (unlikely(pkc->delete_blk_timer))
591                 goto out;
592 
593         /* We only need to plug the race when the block is partially filled.
594          * tpacket_rcv:
595          *              lock(); increment BLOCK_NUM_PKTS; unlock()
596          *              copy_bits() is in progress ...
597          *              timer fires on other cpu:
598          *              we can't retire the current block because copy_bits
599          *              is in progress.
600          *
601          */
602         if (BLOCK_NUM_PKTS(pbd)) {
603                 while (atomic_read(&pkc->blk_fill_in_prog)) {
604                         /* Waiting for skb_copy_bits to finish... */
605                         cpu_relax();
606                 }
607         }
608 
609         if (pkc->last_kactive_blk_num == pkc->kactive_blk_num) {
610                 if (!frozen) {
611                         prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO);
612                         if (!prb_dispatch_next_block(pkc, po))
613                                 goto refresh_timer;
614                         else
615                                 goto out;
616                 } else {
617                         /* Case 1. Queue was frozen because user-space was
618                          *         lagging behind.
619                          */
620                         if (prb_curr_blk_in_use(pkc, pbd)) {
621                                 /*
622                                  * Ok, user-space is still behind.
623                                  * So just refresh the timer.
624                                  */
625                                 goto refresh_timer;
626                         } else {
627                                /* Case 2. queue was frozen,user-space caught up,
628                                 * now the link went idle && the timer fired.
629                                 * We don't have a block to close.So we open this
630                                 * block and restart the timer.
631                                 * opening a block thaws the queue,restarts timer
632                                 * Thawing/timer-refresh is a side effect.
633                                 */
634                                 prb_open_block(pkc, pbd);
635                                 goto out;
636                         }
637                 }
638         }
639 
640 refresh_timer:
641         _prb_refresh_rx_retire_blk_timer(pkc);
642 
643 out:
644         spin_unlock(&po->sk.sk_receive_queue.lock);
645 }
646 
647 static void prb_flush_block(struct tpacket_kbdq_core *pkc1,
648                 struct tpacket_block_desc *pbd1, __u32 status)
649 {
650         /* Flush everything minus the block header */
651 
652 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
653         u8 *start, *end;
654 
655         start = (u8 *)pbd1;
656 
657         /* Skip the block header(we know header WILL fit in 4K) */
658         start += PAGE_SIZE;
659 
660         end = (u8 *)PAGE_ALIGN((unsigned long)pkc1->pkblk_end);
661         for (; start < end; start += PAGE_SIZE)
662                 flush_dcache_page(pgv_to_page(start));
663 
664         smp_wmb();
665 #endif
666 
667         /* Now update the block status. */
668 
669         BLOCK_STATUS(pbd1) = status;
670 
671         /* Flush the block header */
672 
673 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
674         start = (u8 *)pbd1;
675         flush_dcache_page(pgv_to_page(start));
676 
677         smp_wmb();
678 #endif
679 }
680 
681 /*
682  * Side effect:
683  *
684  * 1) flush the block
685  * 2) Increment active_blk_num
686  *
687  * Note:We DONT refresh the timer on purpose.
688  *      Because almost always the next block will be opened.
689  */
690 static void prb_close_block(struct tpacket_kbdq_core *pkc1,
691                 struct tpacket_block_desc *pbd1,
692                 struct packet_sock *po, unsigned int stat)
693 {
694         __u32 status = TP_STATUS_USER | stat;
695 
696         struct tpacket3_hdr *last_pkt;
697         struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
698 
699         if (po->stats.stats3.tp_drops)
700                 status |= TP_STATUS_LOSING;
701 
702         last_pkt = (struct tpacket3_hdr *)pkc1->prev;
703         last_pkt->tp_next_offset = 0;
704 
705         /* Get the ts of the last pkt */
706         if (BLOCK_NUM_PKTS(pbd1)) {
707                 h1->ts_last_pkt.ts_sec = last_pkt->tp_sec;
708                 h1->ts_last_pkt.ts_nsec = last_pkt->tp_nsec;
709         } else {
710                 /* Ok, we tmo'd - so get the current time */
711                 struct timespec ts;
712                 getnstimeofday(&ts);
713                 h1->ts_last_pkt.ts_sec = ts.tv_sec;
714                 h1->ts_last_pkt.ts_nsec = ts.tv_nsec;
715         }
716 
717         smp_wmb();
718 
719         /* Flush the block */
720         prb_flush_block(pkc1, pbd1, status);
721 
722         pkc1->kactive_blk_num = GET_NEXT_PRB_BLK_NUM(pkc1);
723 }
724 
725 static void prb_thaw_queue(struct tpacket_kbdq_core *pkc)
726 {
727         pkc->reset_pending_on_curr_blk = 0;
728 }
729 
730 /*
731  * Side effect of opening a block:
732  *
733  * 1) prb_queue is thawed.
734  * 2) retire_blk_timer is refreshed.
735  *
736  */
737 static void prb_open_block(struct tpacket_kbdq_core *pkc1,
738         struct tpacket_block_desc *pbd1)
739 {
740         struct timespec ts;
741         struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
742 
743         smp_rmb();
744 
745         /* We could have just memset this but we will lose the
746          * flexibility of making the priv area sticky
747          */
748 
749         BLOCK_SNUM(pbd1) = pkc1->knxt_seq_num++;
750         BLOCK_NUM_PKTS(pbd1) = 0;
751         BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
752 
753         getnstimeofday(&ts);
754 
755         h1->ts_first_pkt.ts_sec = ts.tv_sec;
756         h1->ts_first_pkt.ts_nsec = ts.tv_nsec;
757 
758         pkc1->pkblk_start = (char *)pbd1;
759         pkc1->nxt_offset = pkc1->pkblk_start + BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
760 
761         BLOCK_O2FP(pbd1) = (__u32)BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
762         BLOCK_O2PRIV(pbd1) = BLK_HDR_LEN;
763 
764         pbd1->version = pkc1->version;
765         pkc1->prev = pkc1->nxt_offset;
766         pkc1->pkblk_end = pkc1->pkblk_start + pkc1->kblk_size;
767 
768         prb_thaw_queue(pkc1);
769         _prb_refresh_rx_retire_blk_timer(pkc1);
770 
771         smp_wmb();
772 }
773 
774 /*
775  * Queue freeze logic:
776  * 1) Assume tp_block_nr = 8 blocks.
777  * 2) At time 't0', user opens Rx ring.
778  * 3) Some time past 't0', kernel starts filling blocks starting from 0 .. 7
779  * 4) user-space is either sleeping or processing block ''.
780  * 5) tpacket_rcv is currently filling block '7', since there is no space left,
781  *    it will close block-7,loop around and try to fill block ''.
782  *    call-flow:
783  *    __packet_lookup_frame_in_block
784  *      prb_retire_current_block()
785  *      prb_dispatch_next_block()
786  *        |->(BLOCK_STATUS == USER) evaluates to true
787  *    5.1) Since block-0 is currently in-use, we just freeze the queue.
788  * 6) Now there are two cases:
789  *    6.1) Link goes idle right after the queue is frozen.
790  *         But remember, the last open_block() refreshed the timer.
791  *         When this timer expires,it will refresh itself so that we can
792  *         re-open block-0 in near future.
793  *    6.2) Link is busy and keeps on receiving packets. This is a simple
794  *         case and __packet_lookup_frame_in_block will check if block-0
795  *         is free and can now be re-used.
796  */
797 static void prb_freeze_queue(struct tpacket_kbdq_core *pkc,
798                                   struct packet_sock *po)
799 {
800         pkc->reset_pending_on_curr_blk = 1;
801         po->stats.stats3.tp_freeze_q_cnt++;
802 }
803 
804 #define TOTAL_PKT_LEN_INCL_ALIGN(length) (ALIGN((length), V3_ALIGNMENT))
805 
806 /*
807  * If the next block is free then we will dispatch it
808  * and return a good offset.
809  * Else, we will freeze the queue.
810  * So, caller must check the return value.
811  */
812 static void *prb_dispatch_next_block(struct tpacket_kbdq_core *pkc,
813                 struct packet_sock *po)
814 {
815         struct tpacket_block_desc *pbd;
816 
817         smp_rmb();
818 
819         /* 1. Get current block num */
820         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
821 
822         /* 2. If this block is currently in_use then freeze the queue */
823         if (TP_STATUS_USER & BLOCK_STATUS(pbd)) {
824                 prb_freeze_queue(pkc, po);
825                 return NULL;
826         }
827 
828         /*
829          * 3.
830          * open this block and return the offset where the first packet
831          * needs to get stored.
832          */
833         prb_open_block(pkc, pbd);
834         return (void *)pkc->nxt_offset;
835 }
836 
837 static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
838                 struct packet_sock *po, unsigned int status)
839 {
840         struct tpacket_block_desc *pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
841 
842         /* retire/close the current block */
843         if (likely(TP_STATUS_KERNEL == BLOCK_STATUS(pbd))) {
844                 /*
845                  * Plug the case where copy_bits() is in progress on
846                  * cpu-0 and tpacket_rcv() got invoked on cpu-1, didn't
847                  * have space to copy the pkt in the current block and
848                  * called prb_retire_current_block()
849                  *
850                  * We don't need to worry about the TMO case because
851                  * the timer-handler already handled this case.
852                  */
853                 if (!(status & TP_STATUS_BLK_TMO)) {
854                         while (atomic_read(&pkc->blk_fill_in_prog)) {
855                                 /* Waiting for skb_copy_bits to finish... */
856                                 cpu_relax();
857                         }
858                 }
859                 prb_close_block(pkc, pbd, po, status);
860                 return;
861         }
862 }
863 
864 static int prb_curr_blk_in_use(struct tpacket_kbdq_core *pkc,
865                                       struct tpacket_block_desc *pbd)
866 {
867         return TP_STATUS_USER & BLOCK_STATUS(pbd);
868 }
869 
870 static int prb_queue_frozen(struct tpacket_kbdq_core *pkc)
871 {
872         return pkc->reset_pending_on_curr_blk;
873 }
874 
875 static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
876 {
877         struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
878         atomic_dec(&pkc->blk_fill_in_prog);
879 }
880 
881 static void prb_fill_rxhash(struct tpacket_kbdq_core *pkc,
882                         struct tpacket3_hdr *ppd)
883 {
884         ppd->hv1.tp_rxhash = skb_get_rxhash(pkc->skb);
885 }
886 
887 static void prb_clear_rxhash(struct tpacket_kbdq_core *pkc,
888                         struct tpacket3_hdr *ppd)
889 {
890         ppd->hv1.tp_rxhash = 0;
891 }
892 
893 static void prb_fill_vlan_info(struct tpacket_kbdq_core *pkc,
894                         struct tpacket3_hdr *ppd)
895 {
896         if (vlan_tx_tag_present(pkc->skb)) {
897                 ppd->hv1.tp_vlan_tci = vlan_tx_tag_get(pkc->skb);
898                 ppd->tp_status = TP_STATUS_VLAN_VALID;
899         } else {
900                 ppd->hv1.tp_vlan_tci = 0;
901                 ppd->tp_status = TP_STATUS_AVAILABLE;
902         }
903 }
904 
905 static void prb_run_all_ft_ops(struct tpacket_kbdq_core *pkc,
906                         struct tpacket3_hdr *ppd)
907 {
908         prb_fill_vlan_info(pkc, ppd);
909 
910         if (pkc->feature_req_word & TP_FT_REQ_FILL_RXHASH)
911                 prb_fill_rxhash(pkc, ppd);
912         else
913                 prb_clear_rxhash(pkc, ppd);
914 }
915 
916 static void prb_fill_curr_block(char *curr,
917                                 struct tpacket_kbdq_core *pkc,
918                                 struct tpacket_block_desc *pbd,
919                                 unsigned int len)
920 {
921         struct tpacket3_hdr *ppd;
922 
923         ppd  = (struct tpacket3_hdr *)curr;
924         ppd->tp_next_offset = TOTAL_PKT_LEN_INCL_ALIGN(len);
925         pkc->prev = curr;
926         pkc->nxt_offset += TOTAL_PKT_LEN_INCL_ALIGN(len);
927         BLOCK_LEN(pbd) += TOTAL_PKT_LEN_INCL_ALIGN(len);
928         BLOCK_NUM_PKTS(pbd) += 1;
929         atomic_inc(&pkc->blk_fill_in_prog);
930         prb_run_all_ft_ops(pkc, ppd);
931 }
932 
933 /* Assumes caller has the sk->rx_queue.lock */
934 static void *__packet_lookup_frame_in_block(struct packet_sock *po,
935                                             struct sk_buff *skb,
936                                                 int status,
937                                             unsigned int len
938                                             )
939 {
940         struct tpacket_kbdq_core *pkc;
941         struct tpacket_block_desc *pbd;
942         char *curr, *end;
943 
944         pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
945         pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
946 
947         /* Queue is frozen when user space is lagging behind */
948         if (prb_queue_frozen(pkc)) {
949                 /*
950                  * Check if that last block which caused the queue to freeze,
951                  * is still in_use by user-space.
952                  */
953                 if (prb_curr_blk_in_use(pkc, pbd)) {
954                         /* Can't record this packet */
955                         return NULL;
956                 } else {
957                         /*
958                          * Ok, the block was released by user-space.
959                          * Now let's open that block.
960                          * opening a block also thaws the queue.
961                          * Thawing is a side effect.
962                          */
963                         prb_open_block(pkc, pbd);
964                 }
965         }
966 
967         smp_mb();
968         curr = pkc->nxt_offset;
969         pkc->skb = skb;
970         end = (char *)pbd + pkc->kblk_size;
971 
972         /* first try the current block */
973         if (curr+TOTAL_PKT_LEN_INCL_ALIGN(len) < end) {
974                 prb_fill_curr_block(curr, pkc, pbd, len);
975                 return (void *)curr;
976         }
977 
978         /* Ok, close the current block */
979         prb_retire_current_block(pkc, po, 0);
980 
981         /* Now, try to dispatch the next block */
982         curr = (char *)prb_dispatch_next_block(pkc, po);
983         if (curr) {
984                 pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
985                 prb_fill_curr_block(curr, pkc, pbd, len);
986                 return (void *)curr;
987         }
988 
989         /*
990          * No free blocks are available.user_space hasn't caught up yet.
991          * Queue was just frozen and now this packet will get dropped.
992          */
993         return NULL;
994 }
995 
996 static void *packet_current_rx_frame(struct packet_sock *po,
997                                             struct sk_buff *skb,
998                                             int status, unsigned int len)
999 {
1000         char *curr = NULL;
1001         switch (po->tp_version) {
1002         case TPACKET_V1:
1003         case TPACKET_V2:
1004                 curr = packet_lookup_frame(po, &po->rx_ring,
1005                                         po->rx_ring.head, status);
1006                 return curr;
1007         case TPACKET_V3:
1008                 return __packet_lookup_frame_in_block(po, skb, status, len);
1009         default:
1010                 WARN(1, "TPACKET version not supported\n");
1011                 BUG();
1012                 return NULL;
1013         }
1014 }
1015 
1016 static void *prb_lookup_block(struct packet_sock *po,
1017                                      struct packet_ring_buffer *rb,
1018                                      unsigned int idx,
1019                                      int status)
1020 {
1021         struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
1022         struct tpacket_block_desc *pbd = GET_PBLOCK_DESC(pkc, idx);
1023 
1024         if (status != BLOCK_STATUS(pbd))
1025                 return NULL;
1026         return pbd;
1027 }
1028 
1029 static int prb_previous_blk_num(struct packet_ring_buffer *rb)
1030 {
1031         unsigned int prev;
1032         if (rb->prb_bdqc.kactive_blk_num)
1033                 prev = rb->prb_bdqc.kactive_blk_num-1;
1034         else
1035                 prev = rb->prb_bdqc.knum_blocks-1;
1036         return prev;
1037 }
1038 
1039 /* Assumes caller has held the rx_queue.lock */
1040 static void *__prb_previous_block(struct packet_sock *po,
1041                                          struct packet_ring_buffer *rb,
1042                                          int status)
1043 {
1044         unsigned int previous = prb_previous_blk_num(rb);
1045         return prb_lookup_block(po, rb, previous, status);
1046 }
1047 
1048 static void *packet_previous_rx_frame(struct packet_sock *po,
1049                                              struct packet_ring_buffer *rb,
1050                                              int status)
1051 {
1052         if (po->tp_version <= TPACKET_V2)
1053                 return packet_previous_frame(po, rb, status);
1054 
1055         return __prb_previous_block(po, rb, status);
1056 }
1057 
1058 static void packet_increment_rx_head(struct packet_sock *po,
1059                                             struct packet_ring_buffer *rb)
1060 {
1061         switch (po->tp_version) {
1062         case TPACKET_V1:
1063         case TPACKET_V2:
1064                 return packet_increment_head(rb);
1065         case TPACKET_V3:
1066         default:
1067                 WARN(1, "TPACKET version not supported.\n");
1068                 BUG();
1069                 return;
1070         }
1071 }
1072 
1073 static void *packet_previous_frame(struct packet_sock *po,
1074                 struct packet_ring_buffer *rb,
1075                 int status)
1076 {
1077         unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
1078         return packet_lookup_frame(po, rb, previous, status);
1079 }
1080 
1081 static void packet_increment_head(struct packet_ring_buffer *buff)
1082 {
1083         buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
1084 }
1085 
1086 static bool packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
1087 {
1088         struct sock *sk = &po->sk;
1089         bool has_room;
1090 
1091         if (po->prot_hook.func != tpacket_rcv)
1092                 return (atomic_read(&sk->sk_rmem_alloc) + skb->truesize)
1093                         <= sk->sk_rcvbuf;
1094 
1095         spin_lock(&sk->sk_receive_queue.lock);
1096         if (po->tp_version == TPACKET_V3)
1097                 has_room = prb_lookup_block(po, &po->rx_ring,
1098                                             po->rx_ring.prb_bdqc.kactive_blk_num,
1099                                             TP_STATUS_KERNEL);
1100         else
1101                 has_room = packet_lookup_frame(po, &po->rx_ring,
1102                                                po->rx_ring.head,
1103                                                TP_STATUS_KERNEL);
1104         spin_unlock(&sk->sk_receive_queue.lock);
1105 
1106         return has_room;
1107 }
1108 
1109 static void packet_sock_destruct(struct sock *sk)
1110 {
1111         skb_queue_purge(&sk->sk_error_queue);
1112 
1113         WARN_ON(atomic_read(&sk->sk_rmem_alloc));
1114         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
1115 
1116         if (!sock_flag(sk, SOCK_DEAD)) {
1117                 pr_err("Attempt to release alive packet socket: %p\n", sk);
1118                 return;
1119         }
1120 
1121         sk_refcnt_debug_dec(sk);
1122 }
1123 
1124 static int fanout_rr_next(struct packet_fanout *f, unsigned int num)
1125 {
1126         int x = atomic_read(&f->rr_cur) + 1;
1127 
1128         if (x >= num)
1129                 x = 0;
1130 
1131         return x;
1132 }
1133 
1134 static unsigned int fanout_demux_hash(struct packet_fanout *f,
1135                                       struct sk_buff *skb,
1136                                       unsigned int num)
1137 {
1138         return (((u64)skb->rxhash) * num) >> 32;
1139 }
1140 
1141 static unsigned int fanout_demux_lb(struct packet_fanout *f,
1142                                     struct sk_buff *skb,
1143                                     unsigned int num)
1144 {
1145         int cur, old;
1146 
1147         cur = atomic_read(&f->rr_cur);
1148         while ((old = atomic_cmpxchg(&f->rr_cur, cur,
1149                                      fanout_rr_next(f, num))) != cur)
1150                 cur = old;
1151         return cur;
1152 }
1153 
1154 static unsigned int fanout_demux_cpu(struct packet_fanout *f,
1155                                      struct sk_buff *skb,
1156                                      unsigned int num)
1157 {
1158         return smp_processor_id() % num;
1159 }
1160 
1161 static unsigned int fanout_demux_rollover(struct packet_fanout *f,
1162                                           struct sk_buff *skb,
1163                                           unsigned int idx, unsigned int skip,
1164                                           unsigned int num)
1165 {
1166         unsigned int i, j;
1167 
1168         i = j = min_t(int, f->next[idx], num - 1);
1169         do {
1170                 if (i != skip && packet_rcv_has_room(pkt_sk(f->arr[i]), skb)) {
1171                         if (i != j)
1172                                 f->next[idx] = i;
1173                         return i;
1174                 }
1175                 if (++i == num)
1176                         i = 0;
1177         } while (i != j);
1178 
1179         return idx;
1180 }
1181 
1182 static bool fanout_has_flag(struct packet_fanout *f, u16 flag)
1183 {
1184         return f->flags & (flag >> 8);
1185 }
1186 
1187 static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
1188                              struct packet_type *pt, struct net_device *orig_dev)
1189 {
1190         struct packet_fanout *f = pt->af_packet_priv;
1191         unsigned int num = f->num_members;
1192         struct packet_sock *po;
1193         unsigned int idx;
1194 
1195         if (!net_eq(dev_net(dev), read_pnet(&f->net)) ||
1196             !num) {
1197                 kfree_skb(skb);
1198                 return 0;
1199         }
1200 
1201         switch (f->type) {
1202         case PACKET_FANOUT_HASH:
1203         default:
1204                 if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
1205                         skb = ip_check_defrag(skb, IP_DEFRAG_AF_PACKET);
1206                         if (!skb)
1207                                 return 0;
1208                 }
1209                 skb_get_rxhash(skb);
1210                 idx = fanout_demux_hash(f, skb, num);
1211                 break;
1212         case PACKET_FANOUT_LB:
1213                 idx = fanout_demux_lb(f, skb, num);
1214                 break;
1215         case PACKET_FANOUT_CPU:
1216                 idx = fanout_demux_cpu(f, skb, num);
1217                 break;
1218         case PACKET_FANOUT_ROLLOVER:
1219                 idx = fanout_demux_rollover(f, skb, 0, (unsigned int) -1, num);
1220                 break;
1221         }
1222 
1223         po = pkt_sk(f->arr[idx]);
1224         if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER) &&
1225             unlikely(!packet_rcv_has_room(po, skb))) {
1226                 idx = fanout_demux_rollover(f, skb, idx, idx, num);
1227                 po = pkt_sk(f->arr[idx]);
1228         }
1229 
1230         return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
1231 }
1232 
1233 DEFINE_MUTEX(fanout_mutex);
1234 EXPORT_SYMBOL_GPL(fanout_mutex);
1235 static LIST_HEAD(fanout_list);
1236 
1237 static void __fanout_link(struct sock *sk, struct packet_sock *po)
1238 {
1239         struct packet_fanout *f = po->fanout;
1240 
1241         spin_lock(&f->lock);
1242         f->arr[f->num_members] = sk;
1243         smp_wmb();
1244         f->num_members++;
1245         spin_unlock(&f->lock);
1246 }
1247 
1248 static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
1249 {
1250         struct packet_fanout *f = po->fanout;
1251         int i;
1252 
1253         spin_lock(&f->lock);
1254         for (i = 0; i < f->num_members; i++) {
1255                 if (f->arr[i] == sk)
1256                         break;
1257         }
1258         BUG_ON(i >= f->num_members);
1259         f->arr[i] = f->arr[f->num_members - 1];
1260         f->num_members--;
1261         spin_unlock(&f->lock);
1262 }
1263 
1264 static bool match_fanout_group(struct packet_type *ptype, struct sock * sk)
1265 {
1266         if (ptype->af_packet_priv == (void*)((struct packet_sock *)sk)->fanout)
1267                 return true;
1268 
1269         return false;
1270 }
1271 
1272 static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
1273 {
1274         struct packet_sock *po = pkt_sk(sk);
1275         struct packet_fanout *f, *match;
1276         u8 type = type_flags & 0xff;
1277         u8 flags = type_flags >> 8;
1278         int err;
1279 
1280         switch (type) {
1281         case PACKET_FANOUT_ROLLOVER:
1282                 if (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)
1283                         return -EINVAL;
1284         case PACKET_FANOUT_HASH:
1285         case PACKET_FANOUT_LB:
1286         case PACKET_FANOUT_CPU:
1287                 break;
1288         default:
1289                 return -EINVAL;
1290         }
1291 
1292         if (!po->running)
1293                 return -EINVAL;
1294 
1295         if (po->fanout)
1296                 return -EALREADY;
1297 
1298         mutex_lock(&fanout_mutex);
1299         match = NULL;
1300         list_for_each_entry(f, &fanout_list, list) {
1301                 if (f->id == id &&
1302                     read_pnet(&f->net) == sock_net(sk)) {
1303                         match = f;
1304                         break;
1305                 }
1306         }
1307         err = -EINVAL;
1308         if (match && match->flags != flags)
1309                 goto out;
1310         if (!match) {
1311                 err = -ENOMEM;
1312                 match = kzalloc(sizeof(*match), GFP_KERNEL);
1313                 if (!match)
1314                         goto out;
1315                 write_pnet(&match->net, sock_net(sk));
1316                 match->id = id;
1317                 match->type = type;
1318                 match->flags = flags;
1319                 atomic_set(&match->rr_cur, 0);
1320                 INIT_LIST_HEAD(&match->list);
1321                 spin_lock_init(&match->lock);
1322                 atomic_set(&match->sk_ref, 0);
1323                 match->prot_hook.type = po->prot_hook.type;
1324                 match->prot_hook.dev = po->prot_hook.dev;
1325                 match->prot_hook.func = packet_rcv_fanout;
1326                 match->prot_hook.af_packet_priv = match;
1327                 match->prot_hook.id_match = match_fanout_group;
1328                 dev_add_pack(&match->prot_hook);
1329                 list_add(&match->list, &fanout_list);
1330         }
1331         err = -EINVAL;
1332         if (match->type == type &&
1333             match->prot_hook.type == po->prot_hook.type &&
1334             match->prot_hook.dev == po->prot_hook.dev) {
1335                 err = -ENOSPC;
1336                 if (atomic_read(&match->sk_ref) < PACKET_FANOUT_MAX) {
1337                         __dev_remove_pack(&po->prot_hook);
1338                         po->fanout = match;
1339                         atomic_inc(&match->sk_ref);
1340                         __fanout_link(sk, po);
1341                         err = 0;
1342                 }
1343         }
1344 out:
1345         mutex_unlock(&fanout_mutex);
1346         return err;
1347 }
1348 
1349 static void fanout_release(struct sock *sk)
1350 {
1351         struct packet_sock *po = pkt_sk(sk);
1352         struct packet_fanout *f;
1353 
1354         f = po->fanout;
1355         if (!f)
1356                 return;
1357 
1358         mutex_lock(&fanout_mutex);
1359         po->fanout = NULL;
1360 
1361         if (atomic_dec_and_test(&f->sk_ref)) {
1362                 list_del(&f->list);
1363                 dev_remove_pack(&f->prot_hook);
1364                 kfree(f);
1365         }
1366         mutex_unlock(&fanout_mutex);
1367 }
1368 
1369 static const struct proto_ops packet_ops;
1370 
1371 static const struct proto_ops packet_ops_spkt;
1372 
1373 static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
1374                            struct packet_type *pt, struct net_device *orig_dev)
1375 {
1376         struct sock *sk;
1377         struct sockaddr_pkt *spkt;
1378 
1379         /*
1380          *      When we registered the protocol we saved the socket in the data
1381          *      field for just this event.
1382          */
1383 
1384         sk = pt->af_packet_priv;
1385 
1386         /*
1387          *      Yank back the headers [hope the device set this
1388          *      right or kerboom...]
1389          *
1390          *      Incoming packets have ll header pulled,
1391          *      push it back.
1392          *
1393          *      For outgoing ones skb->data == skb_mac_header(skb)
1394          *      so that this procedure is noop.
1395          */
1396 
1397         if (skb->pkt_type == PACKET_LOOPBACK)
1398                 goto out;
1399 
1400         if (!net_eq(dev_net(dev), sock_net(sk)))
1401                 goto out;
1402 
1403         skb = skb_share_check(skb, GFP_ATOMIC);
1404         if (skb == NULL)
1405                 goto oom;
1406 
1407         /* drop any routing info */
1408         skb_dst_drop(skb);
1409 
1410         /* drop conntrack reference */
1411         nf_reset(skb);
1412 
1413         spkt = &PACKET_SKB_CB(skb)->sa.pkt;
1414 
1415         skb_push(skb, skb->data - skb_mac_header(skb));
1416 
1417         /*
1418          *      The SOCK_PACKET socket receives _all_ frames.
1419          */
1420 
1421         spkt->spkt_family = dev->type;
1422         strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
1423         spkt->spkt_protocol = skb->protocol;
1424 
1425         /*
1426          *      Charge the memory to the socket. This is done specifically
1427          *      to prevent sockets using all the memory up.
1428          */
1429 
1430         if (sock_queue_rcv_skb(sk, skb) == 0)
1431                 return 0;
1432 
1433 out:
1434         kfree_skb(skb);
1435 oom:
1436         return 0;
1437 }
1438 
1439 
1440 /*
1441  *      Output a raw packet to a device layer. This bypasses all the other
1442  *      protocol layers and you must therefore supply it with a complete frame
1443  */
1444 
1445 static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock,
1446                                struct msghdr *msg, size_t len)
1447 {
1448         struct sock *sk = sock->sk;
1449         struct sockaddr_pkt *saddr = (struct sockaddr_pkt *)msg->msg_name;
1450         struct sk_buff *skb = NULL;
1451         struct net_device *dev;
1452         __be16 proto = 0;
1453         int err;
1454         int extra_len = 0;
1455 
1456         /*
1457          *      Get and verify the address.
1458          */
1459 
1460         if (saddr) {
1461                 if (msg->msg_namelen < sizeof(struct sockaddr))
1462                         return -EINVAL;
1463                 if (msg->msg_namelen == sizeof(struct sockaddr_pkt))
1464                         proto = saddr->spkt_protocol;
1465         } else
1466                 return -ENOTCONN;       /* SOCK_PACKET must be sent giving an address */
1467 
1468         /*
1469          *      Find the device first to size check it
1470          */
1471 
1472         saddr->spkt_device[sizeof(saddr->spkt_device) - 1] = 0;
1473 retry:
1474         rcu_read_lock();
1475         dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
1476         err = -ENODEV;
1477         if (dev == NULL)
1478                 goto out_unlock;
1479 
1480         err = -ENETDOWN;
1481         if (!(dev->flags & IFF_UP))
1482                 goto out_unlock;
1483 
1484         /*
1485          * You may not queue a frame bigger than the mtu. This is the lowest level
1486          * raw protocol and you must do your own fragmentation at this level.
1487          */
1488 
1489         if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
1490                 if (!netif_supports_nofcs(dev)) {
1491                         err = -EPROTONOSUPPORT;
1492                         goto out_unlock;
1493                 }
1494                 extra_len = 4; /* We're doing our own CRC */
1495         }
1496 
1497         err = -EMSGSIZE;
1498         if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN + extra_len)
1499                 goto out_unlock;
1500 
1501         if (!skb) {
1502                 size_t reserved = LL_RESERVED_SPACE(dev);
1503                 int tlen = dev->needed_tailroom;
1504                 unsigned int hhlen = dev->header_ops ? dev->hard_header_len : 0;
1505 
1506                 rcu_read_unlock();
1507                 skb = sock_wmalloc(sk, len + reserved + tlen, 0, GFP_KERNEL);
1508                 if (skb == NULL)
1509                         return -ENOBUFS;
1510                 /* FIXME: Save some space for broken drivers that write a hard
1511                  * header at transmission time by themselves. PPP is the notable
1512                  * one here. This should really be fixed at the driver level.
1513                  */
1514                 skb_reserve(skb, reserved);
1515                 skb_reset_network_header(skb);
1516 
1517                 /* Try to align data part correctly */
1518                 if (hhlen) {
1519                         skb->data -= hhlen;
1520                         skb->tail -= hhlen;
1521                         if (len < hhlen)
1522                                 skb_reset_network_header(skb);
1523                 }
1524                 err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
1525                 if (err)
1526                         goto out_free;
1527                 goto retry;
1528         }
1529 
1530         if (len > (dev->mtu + dev->hard_header_len + extra_len)) {
1531                 /* Earlier code assumed this would be a VLAN pkt,
1532                  * double-check this now that we have the actual
1533                  * packet in hand.
1534                  */
1535                 struct ethhdr *ehdr;
1536                 skb_reset_mac_header(skb);
1537                 ehdr = eth_hdr(skb);
1538                 if (ehdr->h_proto != htons(ETH_P_8021Q)) {
1539                         err = -EMSGSIZE;
1540                         goto out_unlock;
1541                 }
1542         }
1543 
1544         skb->protocol = proto;
1545         skb->dev = dev;
1546         skb->priority = sk->sk_priority;
1547         skb->mark = sk->sk_mark;
1548 
1549         sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
1550 
1551         if (unlikely(extra_len == 4))
1552                 skb->no_fcs = 1;
1553 
1554         skb_probe_transport_header(skb, 0);
1555 
1556         dev_queue_xmit(skb);
1557         rcu_read_unlock();
1558         return len;
1559 
1560 out_unlock:
1561         rcu_read_unlock();
1562 out_free:
1563         kfree_skb(skb);
1564         return err;
1565 }
1566 
1567 static unsigned int run_filter(const struct sk_buff *skb,
1568                                       const struct sock *sk,
1569                                       unsigned int res)
1570 {
1571         struct sk_filter *filter;
1572 
1573         rcu_read_lock();
1574         filter = rcu_dereference(sk->sk_filter);
1575         if (filter != NULL)
1576                 res = SK_RUN_FILTER(filter, skb);
1577         rcu_read_unlock();
1578 
1579         return res;
1580 }
1581 
1582 /*
1583  * This function makes lazy skb cloning in hope that most of packets
1584  * are discarded by BPF.
1585  *
1586  * Note tricky part: we DO mangle shared skb! skb->data, skb->len
1587  * and skb->cb are mangled. It works because (and until) packets
1588  * falling here are owned by current CPU. Output packets are cloned
1589  * by dev_queue_xmit_nit(), input packets are processed by net_bh
1590  * sequencially, so that if we return skb to original state on exit,
1591  * we will not harm anyone.
1592  */
1593 
1594 static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
1595                       struct packet_type *pt, struct net_device *orig_dev)
1596 {
1597         struct sock *sk;
1598         struct sockaddr_ll *sll;
1599         struct packet_sock *po;
1600         u8 *skb_head = skb->data;
1601         int skb_len = skb->len;
1602         unsigned int snaplen, res;
1603 
1604         if (skb->pkt_type == PACKET_LOOPBACK)
1605                 goto drop;
1606 
1607         sk = pt->af_packet_priv;
1608         po = pkt_sk(sk);
1609 
1610         if (!net_eq(dev_net(dev), sock_net(sk)))
1611                 goto drop;
1612 
1613         skb->dev = dev;
1614 
1615         if (dev->header_ops) {
1616                 /* The device has an explicit notion of ll header,
1617                  * exported to higher levels.
1618                  *
1619                  * Otherwise, the device hides details of its frame
1620                  * structure, so that corresponding packet head is
1621                  * never delivered to user.
1622                  */
1623                 if (sk->sk_type != SOCK_DGRAM)
1624                         skb_push(skb, skb->data - skb_mac_header(skb));
1625                 else if (skb->pkt_type == PACKET_OUTGOING) {
1626                         /* Special case: outgoing packets have ll header at head */
1627                         skb_pull(skb, skb_network_offset(skb));
1628                 }
1629         }
1630 
1631         snaplen = skb->len;
1632 
1633         res = run_filter(skb, sk, snaplen);
1634         if (!res)
1635                 goto drop_n_restore;
1636         if (snaplen > res)
1637                 snaplen = res;
1638 
1639         if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
1640                 goto drop_n_acct;
1641 
1642         if (skb_shared(skb)) {
1643                 struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
1644                 if (nskb == NULL)
1645                         goto drop_n_acct;
1646 
1647                 if (skb_head != skb->data) {
1648                         skb->data = skb_head;
1649                         skb->len = skb_len;
1650                 }
1651                 consume_skb(skb);
1652                 skb = nskb;
1653         }
1654 
1655         BUILD_BUG_ON(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8 >
1656                      sizeof(skb->cb));
1657 
1658         sll = &PACKET_SKB_CB(skb)->sa.ll;
1659         sll->sll_family = AF_PACKET;
1660         sll->sll_hatype = dev->type;
1661         sll->sll_protocol = skb->protocol;
1662         sll->sll_pkttype = skb->pkt_type;
1663         if (unlikely(po->origdev))
1664                 sll->sll_ifindex = orig_dev->ifindex;
1665         else
1666                 sll->sll_ifindex = dev->ifindex;
1667 
1668         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
1669 
1670         PACKET_SKB_CB(skb)->origlen = skb->len;
1671 
1672         if (pskb_trim(skb, snaplen))
1673                 goto drop_n_acct;
1674 
1675         skb_set_owner_r(skb, sk);
1676         skb->dev = NULL;
1677         skb_dst_drop(skb);
1678 
1679         /* drop conntrack reference */
1680         nf_reset(skb);
1681 
1682         spin_lock(&sk->sk_receive_queue.lock);
1683         po->stats.stats1.tp_packets++;
1684         skb->dropcount = atomic_read(&sk->sk_drops);
1685         __skb_queue_tail(&sk->sk_receive_queue, skb);
1686         spin_unlock(&sk->sk_receive_queue.lock);
1687         sk->sk_data_ready(sk, skb->len);
1688         return 0;
1689 
1690 drop_n_acct:
1691         spin_lock(&sk->sk_receive_queue.lock);
1692         po->stats.stats1.tp_drops++;
1693         atomic_inc(&sk->sk_drops);
1694         spin_unlock(&sk->sk_receive_queue.lock);
1695 
1696 drop_n_restore:
1697         if (skb_head != skb->data && skb_shared(skb)) {
1698                 skb->data = skb_head;
1699                 skb->len = skb_len;
1700         }
1701 drop:
1702         consume_skb(skb);
1703         return 0;
1704 }
1705 
1706 static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
1707                        struct packet_type *pt, struct net_device *orig_dev)
1708 {
1709         struct sock *sk;
1710         struct packet_sock *po;
1711         struct sockaddr_ll *sll;
1712         union tpacket_uhdr h;
1713         u8 *skb_head = skb->data;
1714         int skb_len = skb->len;
1715         unsigned int snaplen, res;
1716         unsigned long status = TP_STATUS_USER;
1717         unsigned short macoff, netoff, hdrlen;
1718         struct sk_buff *copy_skb = NULL;
1719         struct timespec ts;
1720         __u32 ts_status;
1721 
1722         if (skb->pkt_type == PACKET_LOOPBACK)
1723                 goto drop;
1724 
1725         sk = pt->af_packet_priv;
1726         po = pkt_sk(sk);
1727 
1728         if (!net_eq(dev_net(dev), sock_net(sk)))
1729                 goto drop;
1730 
1731         if (dev->header_ops) {
1732                 if (sk->sk_type != SOCK_DGRAM)
1733                         skb_push(skb, skb->data - skb_mac_header(skb));
1734                 else if (skb->pkt_type == PACKET_OUTGOING) {
1735                         /* Special case: outgoing packets have ll header at head */
1736                         skb_pull(skb, skb_network_offset(skb));
1737                 }
1738         }
1739 
1740         if (skb->ip_summed == CHECKSUM_PARTIAL)
1741                 status |= TP_STATUS_CSUMNOTREADY;
1742 
1743         snaplen = skb->len;
1744 
1745         res = run_filter(skb, sk, snaplen);
1746         if (!res)
1747                 goto drop_n_restore;
1748         if (snaplen > res)
1749                 snaplen = res;
1750 
1751         if (sk->sk_type == SOCK_DGRAM) {
1752                 macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
1753                                   po->tp_reserve;
1754         } else {
1755                 unsigned int maclen = skb_network_offset(skb);
1756                 netoff = TPACKET_ALIGN(po->tp_hdrlen +
1757                                        (maclen < 16 ? 16 : maclen)) +
1758                         po->tp_reserve;
1759                 macoff = netoff - maclen;
1760         }
1761         if (po->tp_version <= TPACKET_V2) {
1762                 if (macoff + snaplen > po->rx_ring.frame_size) {
1763                         if (po->copy_thresh &&
1764                             atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
1765                                 if (skb_shared(skb)) {
1766                                         copy_skb = skb_clone(skb, GFP_ATOMIC);
1767                                 } else {
1768                                         copy_skb = skb_get(skb);
1769                                         skb_head = skb->data;
1770                                 }
1771                                 if (copy_skb)
1772                                         skb_set_owner_r(copy_skb, sk);
1773                         }
1774                         snaplen = po->rx_ring.frame_size - macoff;
1775                         if ((int)snaplen < 0)
1776                                 snaplen = 0;
1777                 }
1778         }
1779         spin_lock(&sk->sk_receive_queue.lock);
1780         h.raw = packet_current_rx_frame(po, skb,
1781                                         TP_STATUS_KERNEL, (macoff+snaplen));
1782         if (!h.raw)
1783                 goto ring_is_full;
1784         if (po->tp_version <= TPACKET_V2) {
1785                 packet_increment_rx_head(po, &po->rx_ring);
1786         /*
1787          * LOSING will be reported till you read the stats,
1788          * because it's COR - Clear On Read.
1789          * Anyways, moving it for V1/V2 only as V3 doesn't need this
1790          * at packet level.
1791          */
1792                 if (po->stats.stats1.tp_drops)
1793                         status |= TP_STATUS_LOSING;
1794         }
1795         po->stats.stats1.tp_packets++;
1796         if (copy_skb) {
1797                 status |= TP_STATUS_COPY;
1798                 __skb_queue_tail(&sk->sk_receive_queue, copy_skb);
1799         }
1800         spin_unlock(&sk->sk_receive_queue.lock);
1801 
1802         skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
1803 
1804         if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
1805                 getnstimeofday(&ts);
1806 
1807         status |= ts_status;
1808 
1809         switch (po->tp_version) {
1810         case TPACKET_V1:
1811                 h.h1->tp_len = skb->len;
1812                 h.h1->tp_snaplen = snaplen;
1813                 h.h1->tp_mac = macoff;
1814                 h.h1->tp_net = netoff;
1815                 h.h1->tp_sec = ts.tv_sec;
1816                 h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
1817                 hdrlen = sizeof(*h.h1);
1818                 break;
1819         case TPACKET_V2:
1820                 h.h2->tp_len = skb->len;
1821                 h.h2->tp_snaplen = snaplen;
1822                 h.h2->tp_mac = macoff;
1823                 h.h2->tp_net = netoff;
1824                 h.h2->tp_sec = ts.tv_sec;
1825                 h.h2->tp_nsec = ts.tv_nsec;
1826                 if (vlan_tx_tag_present(skb)) {
1827                         h.h2->tp_vlan_tci = vlan_tx_tag_get(skb);
1828                         status |= TP_STATUS_VLAN_VALID;
1829                 } else {
1830                         h.h2->tp_vlan_tci = 0;
1831                 }
1832                 h.h2->tp_padding = 0;
1833                 hdrlen = sizeof(*h.h2);
1834                 break;
1835         case TPACKET_V3:
1836                 /* tp_nxt_offset,vlan are already populated above.
1837                  * So DONT clear those fields here
1838                  */
1839                 h.h3->tp_status |= status;
1840                 h.h3->tp_len = skb->len;
1841                 h.h3->tp_snaplen = snaplen;
1842                 h.h3->tp_mac = macoff;
1843                 h.h3->tp_net = netoff;
1844                 h.h3->tp_sec  = ts.tv_sec;
1845                 h.h3->tp_nsec = ts.tv_nsec;
1846                 hdrlen = sizeof(*h.h3);
1847                 break;
1848         default:
1849                 BUG();
1850         }
1851 
1852         sll = h.raw + TPACKET_ALIGN(hdrlen);
1853         sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
1854         sll->sll_family = AF_PACKET;
1855         sll->sll_hatype = dev->type;
1856         sll->sll_protocol = skb->protocol;
1857         sll->sll_pkttype = skb->pkt_type;
1858         if (unlikely(po->origdev))
1859                 sll->sll_ifindex = orig_dev->ifindex;
1860         else
1861                 sll->sll_ifindex = dev->ifindex;
1862 
1863         smp_mb();
1864 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
1865         {
1866                 u8 *start, *end;
1867 
1868                 if (po->tp_version <= TPACKET_V2) {
1869                         end = (u8 *)PAGE_ALIGN((unsigned long)h.raw
1870                                 + macoff + snaplen);
1871                         for (start = h.raw; start < end; start += PAGE_SIZE)
1872                                 flush_dcache_page(pgv_to_page(start));
1873                 }
1874                 smp_wmb();
1875         }
1876 #endif
1877         if (po->tp_version <= TPACKET_V2)
1878                 __packet_set_status(po, h.raw, status);
1879         else
1880                 prb_clear_blk_fill_status(&po->rx_ring);
1881 
1882         sk->sk_data_ready(sk, 0);
1883 
1884 drop_n_restore:
1885         if (skb_head != skb->data && skb_shared(skb)) {
1886                 skb->data = skb_head;
1887                 skb->len = skb_len;
1888         }
1889 drop:
1890         kfree_skb(skb);
1891         return 0;
1892 
1893 ring_is_full:
1894         po->stats.stats1.tp_drops++;
1895         spin_unlock(&sk->sk_receive_queue.lock);
1896 
1897         sk->sk_data_ready(sk, 0);
1898         kfree_skb(copy_skb);
1899         goto drop_n_restore;
1900 }
1901 
1902 static void tpacket_destruct_skb(struct sk_buff *skb)
1903 {
1904         struct packet_sock *po = pkt_sk(skb->sk);
1905         void *ph;
1906 
1907         if (likely(po->tx_ring.pg_vec)) {
1908                 __u32 ts;
1909 
1910                 ph = skb_shinfo(skb)->destructor_arg;
1911                 BUG_ON(atomic_read(&po->tx_ring.pending) == 0);
1912                 atomic_dec(&po->tx_ring.pending);
1913 
1914                 ts = __packet_set_timestamp(po, ph, skb);
1915                 __packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts);
1916         }
1917 
1918         sock_wfree(skb);
1919 }
1920 
1921 static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
1922                 void *frame, struct net_device *dev, int size_max,
1923                 __be16 proto, unsigned char *addr, int hlen)
1924 {
1925         union tpacket_uhdr ph;
1926         int to_write, offset, len, tp_len, nr_frags, len_max;
1927         struct socket *sock = po->sk.sk_socket;
1928         struct page *page;
1929         void *data;
1930         int err;
1931 
1932         ph.raw = frame;
1933 
1934         skb->protocol = proto;
1935         skb->dev = dev;
1936         skb->priority = po->sk.sk_priority;
1937         skb->mark = po->sk.sk_mark;
1938         sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags);
1939         skb_shinfo(skb)->destructor_arg = ph.raw;
1940 
1941         switch (po->tp_version) {
1942         case TPACKET_V2:
1943                 tp_len = ph.h2->tp_len;
1944                 break;
1945         default:
1946                 tp_len = ph.h1->tp_len;
1947                 break;
1948         }
1949         if (unlikely(tp_len > size_max)) {
1950                 pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
1951                 return -EMSGSIZE;
1952         }
1953 
1954         skb_reserve(skb, hlen);
1955         skb_reset_network_header(skb);
1956         skb_probe_transport_header(skb, 0);
1957 
1958         if (po->tp_tx_has_off) {
1959                 int off_min, off_max, off;
1960                 off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
1961                 off_max = po->tx_ring.frame_size - tp_len;
1962                 if (sock->type == SOCK_DGRAM) {
1963                         switch (po->tp_version) {
1964                         case TPACKET_V2:
1965                                 off = ph.h2->tp_net;
1966                                 break;
1967                         default:
1968                                 off = ph.h1->tp_net;
1969                                 break;
1970                         }
1971                 } else {
1972                         switch (po->tp_version) {
1973                         case TPACKET_V2:
1974                                 off = ph.h2->tp_mac;
1975                                 break;
1976                         default:
1977                                 off = ph.h1->tp_mac;
1978                                 break;
1979                         }
1980                 }
1981                 if (unlikely((off < off_min) || (off_max < off)))
1982                         return -EINVAL;
1983                 data = ph.raw + off;
1984         } else {
1985                 data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
1986         }
1987         to_write = tp_len;
1988 
1989         if (sock->type == SOCK_DGRAM) {
1990                 err = dev_hard_header(skb, dev, ntohs(proto), addr,
1991                                 NULL, tp_len);
1992                 if (unlikely(err < 0))
1993                         return -EINVAL;
1994         } else if (dev->hard_header_len) {
1995                 /* net device doesn't like empty head */
1996                 if (unlikely(tp_len <= dev->hard_header_len)) {
1997                         pr_err("packet size is too short (%d < %d)\n",
1998                                tp_len, dev->hard_header_len);
1999                         return -EINVAL;
2000                 }
2001 
2002                 skb_push(skb, dev->hard_header_len);
2003                 err = skb_store_bits(skb, 0, data,
2004                                 dev->hard_header_len);
2005                 if (unlikely(err))
2006                         return err;
2007 
2008                 data += dev->hard_header_len;
2009                 to_write -= dev->hard_header_len;
2010         }
2011 
2012         offset = offset_in_page(data);
2013         len_max = PAGE_SIZE - offset;
2014         len = ((to_write > len_max) ? len_max : to_write);
2015 
2016         skb->data_len = to_write;
2017         skb->len += to_write;
2018         skb->truesize += to_write;
2019         atomic_add(to_write, &po->sk.sk_wmem_alloc);
2020 
2021         while (likely(to_write)) {
2022                 nr_frags = skb_shinfo(skb)->nr_frags;
2023 
2024                 if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
2025                         pr_err("Packet exceed the number of skb frags(%lu)\n",
2026                                MAX_SKB_FRAGS);
2027                         return -EFAULT;
2028                 }
2029 
2030                 page = pgv_to_page(data);
2031                 data += len;
2032                 flush_dcache_page(page);
2033                 get_page(page);
2034                 skb_fill_page_desc(skb, nr_frags, page, offset, len);
2035                 to_write -= len;
2036                 offset = 0;
2037                 len_max = PAGE_SIZE;
2038                 len = ((to_write > len_max) ? len_max : to_write);
2039         }
2040 
2041         return tp_len;
2042 }
2043 
2044 static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
2045 {
2046         struct sk_buff *skb;
2047         struct net_device *dev;
2048         __be16 proto;
2049         bool need_rls_dev = false;
2050         int err, reserve = 0;
2051         void *ph;
2052         struct sockaddr_ll *saddr = (struct sockaddr_ll *)msg->msg_name;
2053         int tp_len, size_max;
2054         unsigned char *addr;
2055         int len_sum = 0;
2056         int status = TP_STATUS_AVAILABLE;
2057         int hlen, tlen;
2058 
2059         mutex_lock(&po->pg_vec_lock);
2060 
2061         if (saddr == NULL) {
2062                 dev = po->prot_hook.dev;
2063                 proto   = po->num;
2064                 addr    = NULL;
2065         } else {
2066                 err = -EINVAL;
2067                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
2068                         goto out;
2069                 if (msg->msg_namelen < (saddr->sll_halen
2070                                         + offsetof(struct sockaddr_ll,
2071                                                 sll_addr)))
2072                         goto out;
2073                 proto   = saddr->sll_protocol;
2074                 addr    = saddr->sll_addr;
2075                 dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
2076                 need_rls_dev = true;
2077         }
2078 
2079         err = -ENXIO;
2080         if (unlikely(dev == NULL))
2081                 goto out;
2082 
2083         reserve = dev->hard_header_len;
2084 
2085         err = -ENETDOWN;
2086         if (unlikely(!(dev->flags & IFF_UP)))
2087                 goto out_put;
2088 
2089         size_max = po->tx_ring.frame_size
2090                 - (po->tp_hdrlen - sizeof(struct sockaddr_ll));
2091 
2092         if (size_max > dev->mtu + reserve)
2093                 size_max = dev->mtu + reserve;
2094 
2095         do {
2096                 ph = packet_current_frame(po, &po->tx_ring,
2097                                 TP_STATUS_SEND_REQUEST);
2098 
2099                 if (unlikely(ph == NULL)) {
2100                         schedule();
2101                         continue;
2102                 }
2103 
2104                 status = TP_STATUS_SEND_REQUEST;
2105                 hlen = LL_RESERVED_SPACE(dev);
2106                 tlen = dev->needed_tailroom;
2107                 skb = sock_alloc_send_skb(&po->sk,
2108                                 hlen + tlen + sizeof(struct sockaddr_ll),
2109                                 0, &err);
2110 
2111                 if (unlikely(skb == NULL))
2112                         goto out_status;
2113 
2114                 tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
2115                                 addr, hlen);
2116 
2117                 if (unlikely(tp_len < 0)) {
2118                         if (po->tp_loss) {
2119                                 __packet_set_status(po, ph,
2120                                                 TP_STATUS_AVAILABLE);
2121                                 packet_increment_head(&po->tx_ring);
2122                                 kfree_skb(skb);
2123                                 continue;
2124                         } else {
2125                                 status = TP_STATUS_WRONG_FORMAT;
2126                                 err = tp_len;
2127                                 goto out_status;
2128                         }
2129                 }
2130 
2131                 skb->destructor = tpacket_destruct_skb;
2132                 __packet_set_status(po, ph, TP_STATUS_SENDING);
2133                 atomic_inc(&po->tx_ring.pending);
2134 
2135                 status = TP_STATUS_SEND_REQUEST;
2136                 err = dev_queue_xmit(skb);
2137                 if (unlikely(err > 0)) {
2138                         err = net_xmit_errno(err);
2139                         if (err && __packet_get_status(po, ph) ==
2140                                    TP_STATUS_AVAILABLE) {
2141                                 /* skb was destructed already */
2142                                 skb = NULL;
2143                                 goto out_status;
2144                         }
2145                         /*
2146                          * skb was dropped but not destructed yet;
2147                          * let's treat it like congestion or err < 0
2148                          */
2149                         err = 0;
2150                 }
2151                 packet_increment_head(&po->tx_ring);
2152                 len_sum += tp_len;
2153         } while (likely((ph != NULL) ||
2154                         ((!(msg->msg_flags & MSG_DONTWAIT)) &&
2155                          (atomic_read(&po->tx_ring.pending))))
2156                 );
2157 
2158         err = len_sum;
2159         goto out_put;
2160 
2161 out_status:
2162         __packet_set_status(po, ph, status);
2163         kfree_skb(skb);
2164 out_put:
2165         if (need_rls_dev)
2166                 dev_put(dev);
2167 out:
2168         mutex_unlock(&po->pg_vec_lock);
2169         return err;
2170 }
2171 
2172 static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,
2173                                         size_t reserve, size_t len,
2174                                         size_t linear, int noblock,
2175                                         int *err)
2176 {
2177         struct sk_buff *skb;
2178 
2179         /* Under a page?  Don't bother with paged skb. */
2180         if (prepad + len < PAGE_SIZE || !linear)
2181                 linear = len;
2182 
2183         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
2184                                    err);
2185         if (!skb)
2186                 return NULL;
2187 
2188         skb_reserve(skb, reserve);
2189         skb_put(skb, linear);
2190         skb->data_len = len - linear;
2191         skb->len += len - linear;
2192 
2193         return skb;
2194 }
2195 
2196 static int packet_snd(struct socket *sock,
2197                           struct msghdr *msg, size_t len)
2198 {
2199         struct sock *sk = sock->sk;
2200         struct sockaddr_ll *saddr = (struct sockaddr_ll *)msg->msg_name;
2201         struct sk_buff *skb;
2202         struct net_device *dev;
2203         __be16 proto;
2204         bool need_rls_dev = false;
2205         unsigned char *addr;
2206         int err, reserve = 0;
2207         struct virtio_net_hdr vnet_hdr = { 0 };
2208         int offset = 0;
2209         int vnet_hdr_len;
2210         struct packet_sock *po = pkt_sk(sk);
2211         unsigned short gso_type = 0;
2212         int hlen, tlen;
2213         int extra_len = 0;
2214 
2215         /*
2216          *      Get and verify the address.
2217          */
2218 
2219         if (saddr == NULL) {
2220                 dev = po->prot_hook.dev;
2221                 proto   = po->num;
2222                 addr    = NULL;
2223         } else {
2224                 err = -EINVAL;
2225                 if (msg->msg_namelen < sizeof(struct sockaddr_ll))
2226                         goto out;
2227                 if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
2228                         goto out;
2229                 proto   = saddr->sll_protocol;
2230                 addr    = saddr->sll_addr;
2231                 dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
2232                 need_rls_dev = true;
2233         }
2234 
2235         err = -ENXIO;
2236         if (dev == NULL)
2237                 goto out_unlock;
2238         if (sock->type == SOCK_RAW)
2239                 reserve = dev->hard_header_len;
2240 
2241         err = -ENETDOWN;
2242         if (!(dev->flags & IFF_UP))
2243                 goto out_unlock;
2244 
2245         if (po->has_vnet_hdr) {
2246                 vnet_hdr_len = sizeof(vnet_hdr);
2247 
2248                 err = -EINVAL;
2249                 if (len < vnet_hdr_len)
2250                         goto out_unlock;
2251 
2252                 len -= vnet_hdr_len;
2253 
2254                 err = memcpy_fromiovec((void *)&vnet_hdr, msg->msg_iov,
2255                                        vnet_hdr_len);
2256                 if (err < 0)
2257                         goto out_unlock;
2258 
2259                 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
2260                     (vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
2261                       vnet_hdr.hdr_len))
2262                         vnet_hdr.hdr_len = vnet_hdr.csum_start +
2263                                                  vnet_hdr.csum_offset + 2;
2264 
2265                 err = -EINVAL;
2266                 if (vnet_hdr.hdr_len > len)
2267                         goto out_unlock;
2268 
2269                 if (vnet_hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
2270                         switch (vnet_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
2271                         case VIRTIO_NET_HDR_GSO_TCPV4:
2272                                 gso_type = SKB_GSO_TCPV4;
2273                                 break;
2274                         case VIRTIO_NET_HDR_GSO_TCPV6:
2275                                 gso_type = SKB_GSO_TCPV6;
2276                                 break;
2277                         case VIRTIO_NET_HDR_GSO_UDP:
2278                                 gso_type = SKB_GSO_UDP;
2279                                 break;
2280                         default:
2281                                 goto out_unlock;
2282                         }
2283 
2284                         if (vnet_hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
2285                                 gso_type |= SKB_GSO_TCP_ECN;
2286 
2287                         if (vnet_hdr.gso_size == 0)
2288                                 goto out_unlock;
2289 
2290                 }
2291         }
2292 
2293         if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
2294                 if (!netif_supports_nofcs(dev)) {
2295                         err = -EPROTONOSUPPORT;
2296                         goto out_unlock;
2297                 }
2298                 extra_len = 4; /* We're doing our own CRC */
2299         }
2300 
2301         err = -EMSGSIZE;
2302         if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN + extra_len))
2303                 goto out_unlock;
2304 
2305         err = -ENOBUFS;
2306         hlen = LL_RESERVED_SPACE(dev);
2307         tlen = dev->needed_tailroom;
2308         skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, vnet_hdr.hdr_len,
2309                                msg->msg_flags & MSG_DONTWAIT, &err);
2310         if (skb == NULL)
2311                 goto out_unlock;
2312 
2313         skb_set_network_header(skb, reserve);
2314 
2315         err = -EINVAL;
2316         if (sock->type == SOCK_DGRAM &&
2317             (offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len)) < 0)
2318                 goto out_free;
2319 
2320         /* Returns -EFAULT on error */
2321         err = skb_copy_datagram_from_iovec(skb, offset, msg->msg_iov, 0, len);
2322         if (err)
2323                 goto out_free;
2324 
2325         sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
2326 
2327         if (!gso_type && (len > dev->mtu + reserve + extra_len)) {
2328                 /* Earlier code assumed this would be a VLAN pkt,
2329                  * double-check this now that we have the actual
2330                  * packet in hand.
2331                  */
2332                 struct ethhdr *ehdr;
2333                 skb_reset_mac_header(skb);
2334                 ehdr = eth_hdr(skb);
2335                 if (ehdr->h_proto != htons(ETH_P_8021Q)) {
2336                         err = -EMSGSIZE;
2337                         goto out_free;
2338                 }
2339         }
2340 
2341         skb->protocol = proto;
2342         skb->dev = dev;
2343         skb->priority = sk->sk_priority;
2344         skb->mark = sk->sk_mark;
2345 
2346         if (po->has_vnet_hdr) {
2347                 if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
2348                         if (!skb_partial_csum_set(skb, vnet_hdr.csum_start,
2349                                                   vnet_hdr.csum_offset)) {
2350                                 err = -EINVAL;
2351                                 goto out_free;
2352                         }
2353                 }
2354 
2355                 skb_shinfo(skb)->gso_size = vnet_hdr.gso_size;
2356                 skb_shinfo(skb)->gso_type = gso_type;
2357 
2358                 /* Header must be checked, and gso_segs computed. */
2359                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
2360                 skb_shinfo(skb)->gso_segs = 0;
2361 
2362                 len += vnet_hdr_len;
2363         }
2364 
2365         skb_probe_transport_header(skb, reserve);
2366 
2367         if (unlikely(extra_len == 4))
2368                 skb->no_fcs = 1;
2369 
2370         /*
2371          *      Now send it
2372          */
2373 
2374         err = dev_queue_xmit(skb);
2375         if (err > 0 && (err = net_xmit_errno(err)) != 0)
2376                 goto out_unlock;
2377 
2378         if (need_rls_dev)
2379                 dev_put(dev);
2380 
2381         return len;
2382 
2383 out_free:
2384         kfree_skb(skb);
2385 out_unlock:
2386         if (dev && need_rls_dev)
2387                 dev_put(dev);
2388 out:
2389         return err;
2390 }
2391 
2392 static int packet_sendmsg(struct kiocb *iocb, struct socket *sock,
2393                 struct msghdr *msg, size_t len)
2394 {
2395         struct sock *sk = sock->sk;
2396         struct packet_sock *po = pkt_sk(sk);
2397         if (po->tx_ring.pg_vec)
2398                 return tpacket_snd(po, msg);
2399         else
2400                 return packet_snd(sock, msg, len);
2401 }
2402 
2403 /*
2404  *      Close a PACKET socket. This is fairly simple. We immediately go
2405  *      to 'closed' state and remove our protocol entry in the device list.
2406  */
2407 
2408 static int packet_release(struct socket *sock)
2409 {
2410         struct sock *sk = sock->sk;
2411         struct packet_sock *po;
2412         struct net *net;
2413         union tpacket_req_u req_u;
2414 
2415         if (!sk)
2416                 return 0;
2417 
2418         net = sock_net(sk);
2419         po = pkt_sk(sk);
2420 
2421         mutex_lock(&net->packet.sklist_lock);
2422         sk_del_node_init_rcu(sk);
2423         mutex_unlock(&net->packet.sklist_lock);
2424 
2425         preempt_disable();
2426         sock_prot_inuse_add(net, sk->sk_prot, -1);
2427         preempt_enable();
2428 
2429         spin_lock(&po->bind_lock);
2430         unregister_prot_hook(sk, false);
2431         if (po->prot_hook.dev) {
2432                 dev_put(po->prot_hook.dev);
2433                 po->prot_hook.dev = NULL;
2434         }
2435         spin_unlock(&po->bind_lock);
2436 
2437         packet_flush_mclist(sk);
2438 
2439         if (po->rx_ring.pg_vec) {
2440                 memset(&req_u, 0, sizeof(req_u));
2441                 packet_set_ring(sk, &req_u, 1, 0);
2442         }
2443 
2444         if (po->tx_ring.pg_vec) {
2445                 memset(&req_u, 0, sizeof(req_u));
2446                 packet_set_ring(sk, &req_u, 1, 1);
2447         }
2448 
2449         fanout_release(sk);
2450 
2451         synchronize_net();
2452         /*
2453          *      Now the socket is dead. No more input will appear.
2454          */
2455         sock_orphan(sk);
2456         sock->sk = NULL;
2457 
2458         /* Purge queues */
2459 
2460         skb_queue_purge(&sk->sk_receive_queue);
2461         sk_refcnt_debug_release(sk);
2462 
2463         sock_put(sk);
2464         return 0;
2465 }
2466 
2467 /*
2468  *      Attach a packet hook.
2469  */
2470 
2471 static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protocol)
2472 {
2473         struct packet_sock *po = pkt_sk(sk);
2474 
2475         if (po->fanout) {
2476                 if (dev)
2477                         dev_put(dev);
2478 
2479                 return -EINVAL;
2480         }
2481 
2482         lock_sock(sk);
2483 
2484         spin_lock(&po->bind_lock);
2485         unregister_prot_hook(sk, true);
2486         po->num = protocol;
2487         po->prot_hook.type = protocol;
2488         if (po->prot_hook.dev)
2489                 dev_put(po->prot_hook.dev);
2490         po->prot_hook.dev = dev;
2491 
2492         po->ifindex = dev ? dev->ifindex : 0;
2493 
2494         if (protocol == 0)
2495                 goto out_unlock;
2496 
2497         if (!dev || (dev->flags & IFF_UP)) {
2498                 register_prot_hook(sk);
2499         } else {
2500                 sk->sk_err = ENETDOWN;
2501                 if (!sock_flag(sk, SOCK_DEAD))
2502                         sk->sk_error_report(sk);
2503         }
2504 
2505 out_unlock:
2506         spin_unlock(&po->bind_lock);
2507         release_sock(sk);
2508         return 0;
2509 }
2510 
2511 /*
2512  *      Bind a packet socket to a device
2513  */
2514 
2515 static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
2516                             int addr_len)
2517 {
2518         struct sock *sk = sock->sk;
2519         char name[15];
2520         struct net_device *dev;
2521         int err = -ENODEV;
2522 
2523         /*
2524          *      Check legality
2525          */
2526 
2527         if (addr_len != sizeof(struct sockaddr))
2528                 return -EINVAL;
2529         strlcpy(name, uaddr->sa_data, sizeof(name));
2530 
2531         dev = dev_get_by_name(sock_net(sk), name);
2532         if (dev)
2533                 err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
2534         return err;
2535 }
2536 
2537 static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
2538 {
2539         struct sockaddr_ll *sll = (struct sockaddr_ll *)uaddr;
2540         struct sock *sk = sock->sk;
2541         struct net_device *dev = NULL;
2542         int err;
2543 
2544 
2545         /*
2546          *      Check legality
2547          */
2548 
2549         if (addr_len < sizeof(struct sockaddr_ll))
2550                 return -EINVAL;
2551         if (sll->sll_family != AF_PACKET)
2552                 return -EINVAL;
2553 
2554         if (sll->sll_ifindex) {
2555                 err = -ENODEV;
2556                 dev = dev_get_by_index(sock_net(sk), sll->sll_ifindex);
2557                 if (dev == NULL)
2558                         goto out;
2559         }
2560         err = packet_do_bind(sk, dev, sll->sll_protocol ? : pkt_sk(sk)->num);
2561 
2562 out:
2563         return err;
2564 }
2565 
2566 static struct proto packet_proto = {
2567         .name     = "PACKET",
2568         .owner    = THIS_MODULE,
2569         .obj_size = sizeof(struct packet_sock),
2570 };
2571 
2572 /*
2573  *      Create a packet of type SOCK_PACKET.
2574  */
2575 
2576 static int packet_create(struct net *net, struct socket *sock, int protocol,
2577                          int kern)
2578 {
2579         struct sock *sk;
2580         struct packet_sock *po;
2581         __be16 proto = (__force __be16)protocol; /* weird, but documented */
2582         int err;
2583 
2584         if (!ns_capable(net->user_ns, CAP_NET_RAW))
2585                 return -EPERM;
2586         if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
2587             sock->type != SOCK_PACKET)
2588                 return -ESOCKTNOSUPPORT;
2589 
2590         sock->state = SS_UNCONNECTED;
2591 
2592         err = -ENOBUFS;
2593         sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto);
2594         if (sk == NULL)
2595                 goto out;
2596 
2597         sock->ops = &packet_ops;
2598         if (sock->type == SOCK_PACKET)
2599                 sock->ops = &packet_ops_spkt;
2600 
2601         sock_init_data(sock, sk);
2602 
2603         po = pkt_sk(sk);
2604         sk->sk_family = PF_PACKET;
2605         po->num = proto;
2606 
2607         sk->sk_destruct = packet_sock_destruct;
2608         sk_refcnt_debug_inc(sk);
2609 
2610         /*
2611          *      Attach a protocol block
2612          */
2613 
2614         spin_lock_init(&po->bind_lock);
2615         mutex_init(&po->pg_vec_lock);
2616         po->prot_hook.func = packet_rcv;
2617 
2618         if (sock->type == SOCK_PACKET)
2619                 po->prot_hook.func = packet_rcv_spkt;
2620 
2621         po->prot_hook.af_packet_priv = sk;
2622 
2623         if (proto) {
2624                 po->prot_hook.type = proto;
2625                 register_prot_hook(sk);
2626         }
2627 
2628         mutex_lock(&net->packet.sklist_lock);
2629         sk_add_node_rcu(sk, &net->packet.sklist);
2630         mutex_unlock(&net->packet.sklist_lock);
2631 
2632         preempt_disable();
2633         sock_prot_inuse_add(net, &packet_proto, 1);
2634         preempt_enable();
2635 
2636         return 0;
2637 out:
2638         return err;
2639 }
2640 
2641 static int packet_recv_error(struct sock *sk, struct msghdr *msg, int len)
2642 {
2643         struct sock_exterr_skb *serr;
2644         struct sk_buff *skb, *skb2;
2645         int copied, err;
2646 
2647         err = -EAGAIN;
2648         skb = skb_dequeue(&sk->sk_error_queue);
2649         if (skb == NULL)
2650                 goto out;
2651 
2652         copied = skb->len;
2653         if (copied > len) {
2654                 msg->msg_flags |= MSG_TRUNC;
2655                 copied = len;
2656         }
2657         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
2658         if (err)
2659                 goto out_free_skb;
2660 
2661         sock_recv_timestamp(msg, sk, skb);
2662 
2663         serr = SKB_EXT_ERR(skb);
2664         put_cmsg(msg, SOL_PACKET, PACKET_TX_TIMESTAMP,
2665                  sizeof(serr->ee), &serr->ee);
2666 
2667         msg->msg_flags |= MSG_ERRQUEUE;
2668         err = copied;
2669 
2670         /* Reset and regenerate socket error */
2671         spin_lock_bh(&sk->sk_error_queue.lock);
2672         sk->sk_err = 0;
2673         if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
2674                 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
2675                 spin_unlock_bh(&sk->sk_error_queue.lock);
2676                 sk->sk_error_report(sk);
2677         } else
2678                 spin_unlock_bh(&sk->sk_error_queue.lock);
2679 
2680 out_free_skb:
2681         kfree_skb(skb);
2682 out:
2683         return err;
2684 }
2685 
2686 /*
2687  *      Pull a packet from our receive queue and hand it to the user.
2688  *      If necessary we block.
2689  */
2690 
2691 static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
2692                           struct msghdr *msg, size_t len, int flags)
2693 {
2694         struct sock *sk = sock->sk;
2695         struct sk_buff *skb;
2696         int copied, err;
2697         struct sockaddr_ll *sll;
2698         int vnet_hdr_len = 0;
2699 
2700         err = -EINVAL;
2701         if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT|MSG_ERRQUEUE))
2702                 goto out;
2703 
2704 #if 0
2705         /* What error should we return now? EUNATTACH? */
2706         if (pkt_sk(sk)->ifindex < 0)
2707                 return -ENODEV;
2708 #endif
2709 
2710         if (flags & MSG_ERRQUEUE) {
2711                 err = packet_recv_error(sk, msg, len);
2712                 goto out;
2713         }
2714 
2715         /*
2716          *      Call the generic datagram receiver. This handles all sorts
2717          *      of horrible races and re-entrancy so we can forget about it
2718          *      in the protocol layers.
2719          *
2720          *      Now it will return ENETDOWN, if device have just gone down,
2721          *      but then it will block.
2722          */
2723 
2724         skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
2725 
2726         /*
2727          *      An error occurred so return it. Because skb_recv_datagram()
2728          *      handles the blocking we don't see and worry about blocking
2729          *      retries.
2730          */
2731 
2732         if (skb == NULL)
2733                 goto out;
2734 
2735         if (pkt_sk(sk)->has_vnet_hdr) {
2736                 struct virtio_net_hdr vnet_hdr = { 0 };
2737 
2738                 err = -EINVAL;
2739                 vnet_hdr_len = sizeof(vnet_hdr);
2740                 if (len < vnet_hdr_len)
2741                         goto out_free;
2742 
2743                 len -= vnet_hdr_len;
2744 
2745                 if (skb_is_gso(skb)) {
2746                         struct skb_shared_info *sinfo = skb_shinfo(skb);
2747 
2748                         /* This is a hint as to how much should be linear. */
2749                         vnet_hdr.hdr_len = skb_headlen(skb);
2750                         vnet_hdr.gso_size = sinfo->gso_size;
2751                         if (sinfo->gso_type & SKB_GSO_TCPV4)
2752                                 vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
2753                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
2754                                 vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
2755                         else if (sinfo->gso_type & SKB_GSO_UDP)
2756                                 vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
2757                         else if (sinfo->gso_type & SKB_GSO_FCOE)
2758                                 goto out_free;
2759                         else
2760                                 BUG();
2761                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
2762                                 vnet_hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
2763                 } else
2764                         vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
2765 
2766                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
2767                         vnet_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
2768                         vnet_hdr.csum_start = skb_checksum_start_offset(skb);
2769                         vnet_hdr.csum_offset = skb->csum_offset;
2770                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
2771                         vnet_hdr.flags = VIRTIO_NET_HDR_F_DATA_VALID;
2772                 } /* else everything is zero */
2773 
2774                 err = memcpy_toiovec(msg->msg_iov, (void *)&vnet_hdr,
2775                                      vnet_hdr_len);
2776                 if (err < 0)
2777                         goto out_free;
2778         }
2779 
2780         /*
2781          *      If the address length field is there to be filled in, we fill
2782          *      it in now.
2783          */
2784 
2785         sll = &PACKET_SKB_CB(skb)->sa.ll;
2786         if (sock->type == SOCK_PACKET)
2787                 msg->msg_namelen = sizeof(struct sockaddr_pkt);
2788         else
2789                 msg->msg_namelen = sll->sll_halen + offsetof(struct sockaddr_ll, sll_addr);
2790 
2791         /*
2792          *      You lose any data beyond the buffer you gave. If it worries a
2793          *      user program they can ask the device for its MTU anyway.
2794          */
2795 
2796         copied = skb->len;
2797         if (copied > len) {
2798                 copied = len;
2799                 msg->msg_flags |= MSG_TRUNC;
2800         }
2801 
2802         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
2803         if (err)
2804                 goto out_free;
2805 
2806         sock_recv_ts_and_drops(msg, sk, skb);
2807 
2808         if (msg->msg_name)
2809                 memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa,
2810                        msg->msg_namelen);
2811 
2812         if (pkt_sk(sk)->auxdata) {
2813                 struct tpacket_auxdata aux;
2814 
2815                 aux.tp_status = TP_STATUS_USER;
2816                 if (skb->ip_summed == CHECKSUM_PARTIAL)
2817                         aux.tp_status |= TP_STATUS_CSUMNOTREADY;
2818                 aux.tp_len = PACKET_SKB_CB(skb)->origlen;
2819                 aux.tp_snaplen = skb->len;
2820                 aux.tp_mac = 0;
2821                 aux.tp_net = skb_network_offset(skb);
2822                 if (vlan_tx_tag_present(skb)) {
2823                         aux.tp_vlan_tci = vlan_tx_tag_get(skb);
2824                         aux.tp_status |= TP_STATUS_VLAN_VALID;
2825                 } else {
2826                         aux.tp_vlan_tci = 0;
2827                 }
2828                 aux.tp_padding = 0;
2829                 put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
2830         }
2831 
2832         /*
2833          *      Free or return the buffer as appropriate. Again this
2834          *      hides all the races and re-entrancy issues from us.
2835          */
2836         err = vnet_hdr_len + ((flags&MSG_TRUNC) ? skb->len : copied);
2837 
2838 out_free:
2839         skb_free_datagram(sk, skb);
2840 out:
2841         return err;
2842 }
2843 
2844 static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
2845                                int *uaddr_len, int peer)
2846 {
2847         struct net_device *dev;
2848         struct sock *sk = sock->sk;
2849 
2850         if (peer)
2851                 return -EOPNOTSUPP;
2852 
2853         uaddr->sa_family = AF_PACKET;
2854         memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
2855         rcu_read_lock();
2856         dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
2857         if (dev)
2858                 strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
2859         rcu_read_unlock();
2860         *uaddr_len = sizeof(*uaddr);
2861 
2862         return 0;
2863 }
2864 
2865 static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
2866                           int *uaddr_len, int peer)
2867 {
2868         struct net_device *dev;
2869         struct sock *sk = sock->sk;
2870         struct packet_sock *po = pkt_sk(sk);
2871         DECLARE_SOCKADDR(struct sockaddr_ll *, sll, uaddr);
2872 
2873         if (peer)
2874                 return -EOPNOTSUPP;
2875 
2876         sll->sll_family = AF_PACKET;
2877         sll->sll_ifindex = po->ifindex;
2878         sll->sll_protocol = po->num;
2879         sll->sll_pkttype = 0;
2880         rcu_read_lock();
2881         dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
2882         if (dev) {
2883                 sll->sll_hatype = dev->type;
2884                 sll->sll_halen = dev->addr_len;
2885                 memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
2886         } else {
2887                 sll->sll_hatype = 0;    /* Bad: we have no ARPHRD_UNSPEC */
2888                 sll->sll_halen = 0;
2889         }
2890         rcu_read_unlock();
2891         *uaddr_len = offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
2892 
2893         return 0;
2894 }
2895 
2896 static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
2897                          int what)
2898 {
2899         switch (i->type) {
2900         case PACKET_MR_MULTICAST:
2901                 if (i->alen != dev->addr_len)
2902                         return -EINVAL;
2903                 if (what > 0)
2904                         return dev_mc_add(dev, i->addr);
2905                 else
2906                         return dev_mc_del(dev, i->addr);
2907                 break;
2908         case PACKET_MR_PROMISC:
2909                 return dev_set_promiscuity(dev, what);
2910                 break;
2911         case PACKET_MR_ALLMULTI:
2912                 return dev_set_allmulti(dev, what);
2913                 break;
2914         case PACKET_MR_UNICAST:
2915                 if (i->alen != dev->addr_len)
2916                         return -EINVAL;
2917                 if (what > 0)
2918                         return dev_uc_add(dev, i->addr);
2919                 else
2920                         return dev_uc_del(dev, i->addr);
2921                 break;
2922         default:
2923                 break;
2924         }
2925         return 0;
2926 }
2927 
2928 static void packet_dev_mclist(struct net_device *dev, struct packet_mclist *i, int what)
2929 {
2930         for ( ; i; i = i->next) {
2931                 if (i->ifindex == dev->ifindex)
2932                         packet_dev_mc(dev, i, what);
2933         }
2934 }
2935 
2936 static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
2937 {
2938         struct packet_sock *po = pkt_sk(sk);
2939         struct packet_mclist *ml, *i;
2940         struct net_device *dev;
2941         int err;
2942 
2943         rtnl_lock();
2944 
2945         err = -ENODEV;
2946         dev = __dev_get_by_index(sock_net(sk), mreq->mr_ifindex);
2947         if (!dev)
2948                 goto done;
2949 
2950         err = -EINVAL;
2951         if (mreq->mr_alen > dev->addr_len)
2952                 goto done;
2953 
2954         err = -ENOBUFS;
2955         i = kmalloc(sizeof(*i), GFP_KERNEL);
2956         if (i == NULL)
2957                 goto done;
2958 
2959         err = 0;
2960         for (ml = po->mclist; ml; ml = ml->next) {
2961                 if (ml->ifindex == mreq->mr_ifindex &&
2962                     ml->type == mreq->mr_type &&
2963                     ml->alen == mreq->mr_alen &&
2964                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
2965                         ml->count++;
2966                         /* Free the new element ... */
2967                         kfree(i);
2968                         goto done;
2969                 }
2970         }
2971 
2972         i->type = mreq->mr_type;
2973         i->ifindex = mreq->mr_ifindex;
2974         i->alen = mreq->mr_alen;
2975         memcpy(i->addr, mreq->mr_address, i->alen);
2976         i->count = 1;
2977         i->next = po->mclist;
2978         po->mclist = i;
2979         err = packet_dev_mc(dev, i, 1);
2980         if (err) {
2981                 po->mclist = i->next;
2982                 kfree(i);
2983         }
2984 
2985 done:
2986         rtnl_unlock();
2987         return err;
2988 }
2989 
2990 static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
2991 {
2992         struct packet_mclist *ml, **mlp;
2993 
2994         rtnl_lock();
2995 
2996         for (mlp = &pkt_sk(sk)->mclist; (ml = *mlp) != NULL; mlp = &ml->next) {
2997                 if (ml->ifindex == mreq->mr_ifindex &&
2998                     ml->type == mreq->mr_type &&
2999                     ml->alen == mreq->mr_alen &&
3000                     memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
3001                         if (--ml->count == 0) {
3002                                 struct net_device *dev;
3003                                 *mlp = ml->next;
3004                                 dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
3005                                 if (dev)
3006                                         packet_dev_mc(dev, ml, -1);
3007                                 kfree(ml);
3008                         }
3009                         rtnl_unlock();
3010                         return 0;
3011                 }
3012         }
3013         rtnl_unlock();
3014         return -EADDRNOTAVAIL;
3015 }
3016 
3017 static void packet_flush_mclist(struct sock *sk)
3018 {
3019         struct packet_sock *po = pkt_sk(sk);
3020         struct packet_mclist *ml;
3021 
3022         if (!po->mclist)
3023                 return;
3024 
3025         rtnl_lock();
3026         while ((ml = po->mclist) != NULL) {
3027                 struct net_device *dev;
3028 
3029                 po->mclist = ml->next;
3030                 dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
3031                 if (dev != NULL)
3032                         packet_dev_mc(dev, ml, -1);
3033                 kfree(ml);
3034         }
3035         rtnl_unlock();
3036 }
3037 
3038 static int
3039 packet_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
3040 {
3041         struct sock *sk = sock->sk;
3042         struct packet_sock *po = pkt_sk(sk);
3043         int ret;
3044 
3045         if (level != SOL_PACKET)
3046                 return -ENOPROTOOPT;
3047 
3048         switch (optname) {
3049         case PACKET_ADD_MEMBERSHIP:
3050         case PACKET_DROP_MEMBERSHIP:
3051         {
3052                 struct packet_mreq_max mreq;
3053                 int len = optlen;
3054                 memset(&mreq, 0, sizeof(mreq));
3055                 if (len < sizeof(struct packet_mreq))
3056                         return -EINVAL;
3057                 if (len > sizeof(mreq))
3058                         len = sizeof(mreq);
3059                 if (copy_from_user(&mreq, optval, len))
3060                         return -EFAULT;
3061                 if (len < (mreq.mr_alen + offsetof(struct packet_mreq, mr_address)))
3062                         return -EINVAL;
3063                 if (optname == PACKET_ADD_MEMBERSHIP)
3064                         ret = packet_mc_add(sk, &mreq);
3065                 else
3066                         ret = packet_mc_drop(sk, &mreq);
3067                 return ret;
3068         }
3069 
3070         case PACKET_RX_RING:
3071         case PACKET_TX_RING:
3072         {
3073                 union tpacket_req_u req_u;
3074                 int len;
3075 
3076                 switch (po->tp_version) {
3077                 case TPACKET_V1:
3078                 case TPACKET_V2:
3079                         len = sizeof(req_u.req);
3080                         break;
3081                 case TPACKET_V3:
3082                 default:
3083                         len = sizeof(req_u.req3);
3084                         break;
3085                 }
3086                 if (optlen < len)
3087                         return -EINVAL;
3088                 if (pkt_sk(sk)->has_vnet_hdr)
3089                         return -EINVAL;
3090                 if (copy_from_user(&req_u.req, optval, len))
3091                         return -EFAULT;
3092                 return packet_set_ring(sk, &req_u, 0,
3093                         optname == PACKET_TX_RING);
3094         }
3095         case PACKET_COPY_THRESH:
3096         {
3097                 int val;
3098 
3099                 if (optlen != sizeof(val))
3100                         return -EINVAL;
3101                 if (copy_from_user(&val, optval, sizeof(val)))
3102                         return -EFAULT;
3103 
3104                 pkt_sk(sk)->copy_thresh = val;
3105                 return 0;
3106         }
3107         case PACKET_VERSION:
3108         {
3109                 int val;
3110 
3111                 if (optlen != sizeof(val))
3112                         return -EINVAL;
3113                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
3114                         return -EBUSY;
3115                 if (copy_from_user(&val, optval, sizeof(val)))
3116                         return -EFAULT;
3117                 switch (val) {
3118                 case TPACKET_V1:
3119                 case TPACKET_V2:
3120                 case TPACKET_V3:
3121                         po->tp_version = val;
3122                         return 0;
3123                 default:
3124                         return -EINVAL;
3125                 }
3126         }
3127         case PACKET_RESERVE:
3128         {
3129                 unsigned int val;
3130 
3131                 if (optlen != sizeof(val))
3132                         return -EINVAL;
3133                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
3134                         return -EBUSY;
3135                 if (copy_from_user(&val, optval, sizeof(val)))
3136                         return -EFAULT;
3137                 po->tp_reserve = val;
3138                 return 0;
3139         }
3140         case PACKET_LOSS:
3141         {
3142                 unsigned int val;
3143 
3144                 if (optlen != sizeof(val))
3145                         return -EINVAL;
3146                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
3147                         return -EBUSY;
3148                 if (copy_from_user(&val, optval, sizeof(val)))
3149                         return -EFAULT;
3150                 po->tp_loss = !!val;
3151                 return 0;
3152         }
3153         case PACKET_AUXDATA:
3154         {
3155                 int val;
3156 
3157                 if (optlen < sizeof(val))
3158                         return -EINVAL;
3159                 if (copy_from_user(&val, optval, sizeof(val)))
3160                         return -EFAULT;
3161 
3162                 po->auxdata = !!val;
3163                 return 0;
3164         }
3165         case PACKET_ORIGDEV:
3166         {
3167                 int val;
3168 
3169                 if (optlen < sizeof(val))
3170                         return -EINVAL;
3171                 if (copy_from_user(&val, optval, sizeof(val)))
3172                         return -EFAULT;
3173 
3174                 po->origdev = !!val;
3175                 return 0;
3176         }
3177         case PACKET_VNET_HDR:
3178         {
3179                 int val;
3180 
3181                 if (sock->type != SOCK_RAW)
3182                         return -EINVAL;
3183                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
3184                         return -EBUSY;
3185                 if (optlen < sizeof(val))
3186                         return -EINVAL;
3187                 if (copy_from_user(&val, optval, sizeof(val)))
3188                         return -EFAULT;
3189 
3190                 po->has_vnet_hdr = !!val;
3191                 return 0;
3192         }
3193         case PACKET_TIMESTAMP:
3194         {
3195                 int val;
3196 
3197                 if (optlen != sizeof(val))
3198                         return -EINVAL;
3199                 if (copy_from_user(&val, optval, sizeof(val)))
3200                         return -EFAULT;
3201 
3202                 po->tp_tstamp = val;
3203                 return 0;
3204         }
3205         case PACKET_FANOUT:
3206         {
3207                 int val;
3208 
3209                 if (optlen != sizeof(val))
3210                         return -EINVAL;
3211                 if (copy_from_user(&val, optval, sizeof(val)))
3212                         return -EFAULT;
3213 
3214                 return fanout_add(sk, val & 0xffff, val >> 16);
3215         }
3216         case PACKET_TX_HAS_OFF:
3217         {
3218                 unsigned int val;
3219 
3220                 if (optlen != sizeof(val))
3221                         return -EINVAL;
3222                 if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
3223                         return -EBUSY;
3224                 if (copy_from_user(&val, optval, sizeof(val)))
3225                         return -EFAULT;
3226                 po->tp_tx_has_off = !!val;
3227                 return 0;
3228         }
3229         default:
3230                 return -ENOPROTOOPT;
3231         }
3232 }
3233 
3234 static int packet_getsockopt(struct socket *sock, int level, int optname,
3235                              char __user *optval, int __user *optlen)
3236 {
3237         int len;
3238         int val, lv = sizeof(val);
3239         struct sock *sk = sock->sk;
3240         struct packet_sock *po = pkt_sk(sk);
3241         void *data = &val;
3242         union tpacket_stats_u st;
3243 
3244         if (level != SOL_PACKET)
3245                 return -ENOPROTOOPT;
3246 
3247         if (get_user(len, optlen))
3248                 return -EFAULT;
3249 
3250         if (len < 0)
3251                 return -EINVAL;
3252 
3253         switch (optname) {
3254         case PACKET_STATISTICS:
3255                 spin_lock_bh(&sk->sk_receive_queue.lock);
3256                 memcpy(&st, &po->stats, sizeof(st));
3257                 memset(&po->stats, 0, sizeof(po->stats));
3258                 spin_unlock_bh(&sk->sk_receive_queue.lock);
3259 
3260                 if (po->tp_version == TPACKET_V3) {
3261                         lv = sizeof(struct tpacket_stats_v3);
3262                         st.stats3.tp_packets += st.stats3.tp_drops;
3263                         data = &st.stats3;
3264                 } else {
3265                         lv = sizeof(struct tpacket_stats);
3266                         st.stats1.tp_packets += st.stats1.tp_drops;
3267                         data = &st.stats1;
3268                 }
3269 
3270                 break;
3271         case PACKET_AUXDATA:
3272                 val = po->auxdata;
3273                 break;
3274         case PACKET_ORIGDEV:
3275                 val = po->origdev;
3276                 break;
3277         case PACKET_VNET_HDR:
3278                 val = po->has_vnet_hdr;
3279                 break;
3280         case PACKET_VERSION:
3281                 val = po->tp_version;
3282                 break;
3283         case PACKET_HDRLEN:
3284                 if (len > sizeof(int))
3285                         len = sizeof(int);
3286                 if (copy_from_user(&val, optval, len))
3287                         return -EFAULT;
3288                 switch (val) {
3289                 case TPACKET_V1:
3290                         val = sizeof(struct tpacket_hdr);
3291                         break;
3292                 case TPACKET_V2:
3293                         val = sizeof(struct tpacket2_hdr);
3294                         break;
3295                 case TPACKET_V3:
3296                         val = sizeof(struct tpacket3_hdr);
3297                         break;
3298                 default:
3299                         return -EINVAL;
3300                 }
3301                 break;
3302         case PACKET_RESERVE:
3303                 val = po->tp_reserve;
3304                 break;
3305         case PACKET_LOSS:
3306                 val = po->tp_loss;
3307                 break;
3308         case PACKET_TIMESTAMP:
3309                 val = po->tp_tstamp;
3310                 break;
3311         case PACKET_FANOUT:
3312                 val = (po->fanout ?
3313                        ((u32)po->fanout->id |
3314                         ((u32)po->fanout->type << 16) |
3315                         ((u32)po->fanout->flags << 24)) :
3316                        0);
3317                 break;
3318         case PACKET_TX_HAS_OFF:
3319                 val = po->tp_tx_has_off;
3320                 break;
3321         default:
3322                 return -ENOPROTOOPT;
3323         }
3324 
3325         if (len > lv)
3326                 len = lv;
3327         if (put_user(len, optlen))
3328                 return -EFAULT;
3329         if (copy_to_user(optval, data, len))
3330                 return -EFAULT;
3331         return 0;
3332 }
3333 
3334 
3335 static int packet_notifier(struct notifier_block *this,
3336                            unsigned long msg, void *ptr)
3337 {
3338         struct sock *sk;
3339         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
3340         struct net *net = dev_net(dev);
3341 
3342         rcu_read_lock();
3343         sk_for_each_rcu(sk, &net->packet.sklist) {
3344                 struct packet_sock *po = pkt_sk(sk);
3345 
3346                 switch (msg) {
3347                 case NETDEV_UNREGISTER:
3348                         if (po->mclist)
3349                                 packet_dev_mclist(dev, po->mclist, -1);
3350                         /* fallthrough */
3351 
3352                 case NETDEV_DOWN:
3353                         if (dev->ifindex == po->ifindex) {
3354                                 spin_lock(&po->bind_lock);
3355                                 if (po->running) {
3356                                         __unregister_prot_hook(sk, false);
3357                                         sk->sk_err = ENETDOWN;
3358                                         if (!sock_flag(sk, SOCK_DEAD))
3359                                                 sk->sk_error_report(sk);
3360                                 }
3361                                 if (msg == NETDEV_UNREGISTER) {
3362                                         po->ifindex = -1;
3363                                         if (po->prot_hook.dev)
3364                                                 dev_put(po->prot_hook.dev);
3365                                         po->prot_hook.dev = NULL;
3366                                 }
3367                                 spin_unlock(&po->bind_lock);
3368                         }
3369                         break;
3370                 case NETDEV_UP:
3371                         if (dev->ifindex == po->ifindex) {
3372                                 spin_lock(&po->bind_lock);
3373                                 if (po->num)
3374                                         register_prot_hook(sk);
3375                                 spin_unlock(&po->bind_lock);
3376                         }
3377                         break;
3378                 }
3379         }
3380         rcu_read_unlock();
3381         return NOTIFY_DONE;
3382 }
3383 
3384 
3385 static int packet_ioctl(struct socket *sock, unsigned int cmd,
3386                         unsigned long arg)
3387 {
3388         struct sock *sk = sock->sk;
3389 
3390         switch (cmd) {
3391         case SIOCOUTQ:
3392         {
3393                 int amount = sk_wmem_alloc_get(sk);
3394 
3395                 return put_user(amount, (int __user *)arg);
3396         }
3397         case SIOCINQ:
3398         {
3399                 struct sk_buff *skb;
3400                 int amount = 0;
3401 
3402                 spin_lock_bh(&sk->sk_receive_queue.lock);
3403                 skb = skb_peek(&sk->sk_receive_queue);
3404                 if (skb)
3405                         amount = skb->len;
3406                 spin_unlock_bh(&sk->sk_receive_queue.lock);
3407                 return put_user(amount, (int __user *)arg);
3408         }
3409         case SIOCGSTAMP:
3410                 return sock_get_timestamp(sk, (struct timeval __user *)arg);
3411         case SIOCGSTAMPNS:
3412                 return sock_get_timestampns(sk, (struct timespec __user *)arg);
3413 
3414 #ifdef CONFIG_INET
3415         case SIOCADDRT:
3416         case SIOCDELRT:
3417         case SIOCDARP:
3418         case SIOCGARP:
3419         case SIOCSARP:
3420         case SIOCGIFADDR:
3421         case SIOCSIFADDR:
3422         case SIOCGIFBRDADDR:
3423         case SIOCSIFBRDADDR:
3424         case SIOCGIFNETMASK:
3425         case SIOCSIFNETMASK:
3426         case SIOCGIFDSTADDR:
3427         case SIOCSIFDSTADDR:
3428         case SIOCSIFFLAGS:
3429                 return inet_dgram_ops.ioctl(sock, cmd, arg);
3430 #endif
3431 
3432         default:
3433                 return -ENOIOCTLCMD;
3434         }
3435         return 0;
3436 }
3437 
3438 static unsigned int packet_poll(struct file *file, struct socket *sock,
3439                                 poll_table *wait)
3440 {
3441         struct sock *sk = sock->sk;
3442         struct packet_sock *po = pkt_sk(sk);
3443         unsigned int mask = datagram_poll(file, sock, wait);
3444 
3445         spin_lock_bh(&sk->sk_receive_queue.lock);
3446         if (po->rx_ring.pg_vec) {
3447                 if (!packet_previous_rx_frame(po, &po->rx_ring,
3448                         TP_STATUS_KERNEL))
3449                         mask |= POLLIN | POLLRDNORM;
3450         }
3451         spin_unlock_bh(&sk->sk_receive_queue.lock);
3452         spin_lock_bh(&sk->sk_write_queue.lock);
3453         if (po->tx_ring.pg_vec) {
3454                 if (packet_current_frame(po, &po->tx_ring, TP_STATUS_AVAILABLE))
3455                         mask |= POLLOUT | POLLWRNORM;
3456         }
3457         spin_unlock_bh(&sk->sk_write_queue.lock);
3458         return mask;
3459 }
3460 
3461 
3462 /* Dirty? Well, I still did not learn better way to account
3463  * for user mmaps.
3464  */
3465 
3466 static void packet_mm_open(struct vm_area_struct *vma)
3467 {
3468         struct file *file = vma->vm_file;
3469         struct socket *sock = file->private_data;
3470         struct sock *sk = sock->sk;
3471 
3472         if (sk)
3473                 atomic_inc(&pkt_sk(sk)->mapped);
3474 }
3475 
3476 static void packet_mm_close(struct vm_area_struct *vma)
3477 {
3478         struct file *file = vma->vm_file;
3479         struct socket *sock = file->private_data;
3480         struct sock *sk = sock->sk;
3481 
3482         if (sk)
3483                 atomic_dec(&pkt_sk(sk)->mapped);
3484 }
3485 
3486 static const struct vm_operations_struct packet_mmap_ops = {
3487         .open   =       packet_mm_open,
3488         .close  =       packet_mm_close,
3489 };
3490 
3491 static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
3492                         unsigned int len)
3493 {
3494         int i;
3495 
3496         for (i = 0; i < len; i++) {
3497                 if (likely(pg_vec[i].buffer)) {
3498                         if (is_vmalloc_addr(pg_vec[i].buffer))
3499                                 vfree(pg_vec[i].buffer);
3500                         else
3501                                 free_pages((unsigned long)pg_vec[i].buffer,
3502                                            order);
3503                         pg_vec[i].buffer = NULL;
3504                 }
3505         }
3506         kfree(pg_vec);
3507 }
3508 
3509 static char *alloc_one_pg_vec_page(unsigned long order)
3510 {
3511         char *buffer = NULL;
3512         gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
3513                           __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
3514 
3515         buffer = (char *) __get_free_pages(gfp_flags, order);
3516 
3517         if (buffer)
3518                 return buffer;
3519 
3520         /*
3521          * __get_free_pages failed, fall back to vmalloc
3522          */
3523         buffer = vzalloc((1 << order) * PAGE_SIZE);
3524 
3525         if (buffer)
3526                 return buffer;
3527 
3528         /*
3529          * vmalloc failed, lets dig into swap here
3530          */
3531         gfp_flags &= ~__GFP_NORETRY;
3532         buffer = (char *)__get_free_pages(gfp_flags, order);
3533         if (buffer)
3534                 return buffer;
3535 
3536         /*
3537          * complete and utter failure
3538          */
3539         return NULL;
3540 }
3541 
3542 static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
3543 {
3544         unsigned int block_nr = req->tp_block_nr;
3545         struct pgv *pg_vec;
3546         int i;
3547 
3548         pg_vec = kcalloc(block_nr, sizeof(struct pgv), GFP_KERNEL);
3549         if (unlikely(!pg_vec))
3550                 goto out;
3551 
3552         for (i = 0; i < block_nr; i++) {
3553                 pg_vec[i].buffer = alloc_one_pg_vec_page(order);
3554                 if (unlikely(!pg_vec[i].buffer))
3555                         goto out_free_pgvec;
3556         }
3557 
3558 out:
3559         return pg_vec;
3560 
3561 out_free_pgvec:
3562         free_pg_vec(pg_vec, order, block_nr);
3563         pg_vec = NULL;
3564         goto out;
3565 }
3566 
3567 static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
3568                 int closing, int tx_ring)
3569 {
3570         struct pgv *pg_vec = NULL;
3571         struct packet_sock *po = pkt_sk(sk);
3572         int was_running, order = 0;
3573         struct packet_ring_buffer *rb;
3574         struct sk_buff_head *rb_queue;
3575         __be16 num;
3576         int err = -EINVAL;
3577         /* Added to avoid minimal code churn */
3578         struct tpacket_req *req = &req_u->req;
3579 
3580         /* Opening a Tx-ring is NOT supported in TPACKET_V3 */
3581         if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
3582                 WARN(1, "Tx-ring is not supported.\n");
3583                 goto out;
3584         }
3585 
3586         rb = tx_ring ? &po->tx_ring : &po->rx_ring;
3587         rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
3588 
3589         err = -EBUSY;
3590         if (!closing) {
3591                 if (atomic_read(&po->mapped))
3592                         goto out;
3593                 if (atomic_read(&rb->pending))
3594                         goto out;
3595         }
3596 
3597         if (req->tp_block_nr) {
3598                 /* Sanity tests and some calculations */
3599                 err = -EBUSY;
3600                 if (unlikely(rb->pg_vec))
3601                         goto out;
3602 
3603                 switch (po->tp_version) {
3604                 case TPACKET_V1:
3605                         po->tp_hdrlen = TPACKET_HDRLEN;
3606                         break;
3607                 case TPACKET_V2:
3608                         po->tp_hdrlen = TPACKET2_HDRLEN;
3609                         break;
3610                 case TPACKET_V3:
3611                         po->tp_hdrlen = TPACKET3_HDRLEN;
3612                         break;
3613                 }
3614 
3615                 err = -EINVAL;
3616                 if (unlikely((int)req->tp_block_size <= 0))
3617                         goto out;
3618                 if (unlikely(req->tp_block_size & (PAGE_SIZE - 1)))
3619                         goto out;
3620                 if (unlikely(req->tp_frame_size < po->tp_hdrlen +
3621                                         po->tp_reserve))
3622                         goto out;
3623                 if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
3624                         goto out;
3625 
3626                 rb->frames_per_block = req->tp_block_size/req->tp_frame_size;
3627                 if (unlikely(rb->frames_per_block <= 0))
3628                         goto out;
3629                 if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
3630                                         req->tp_frame_nr))
3631                         goto out;
3632 
3633                 err = -ENOMEM;
3634                 order = get_order(req->tp_block_size);
3635                 pg_vec = alloc_pg_vec(req, order);
3636                 if (unlikely(!pg_vec))
3637                         goto out;
3638                 switch (po->tp_version) {
3639                 case TPACKET_V3:
3640                 /* Transmit path is not supported. We checked
3641                  * it above but just being paranoid
3642                  */
3643                         if (!tx_ring)
3644                                 init_prb_bdqc(po, rb, pg_vec, req_u, tx_ring);
3645                                 break;
3646                 default:
3647                         break;
3648                 }
3649         }
3650         /* Done */
3651         else {
3652                 err = -EINVAL;
3653                 if (unlikely(req->tp_frame_nr))
3654                         goto out;
3655         }
3656 
3657         lock_sock(sk);
3658 
3659         /* Detach socket from network */
3660         spin_lock(&po->bind_lock);
3661         was_running = po->running;
3662         num = po->num;
3663         if (was_running) {
3664                 po->num = 0;
3665                 __unregister_prot_hook(sk, false);
3666         }
3667         spin_unlock(&po->bind_lock);
3668 
3669         synchronize_net();
3670 
3671         err = -EBUSY;
3672         mutex_lock(&po->pg_vec_lock);
3673         if (closing || atomic_read(&po->mapped) == 0) {
3674                 err = 0;
3675                 spin_lock_bh(&rb_queue->lock);
3676                 swap(rb->pg_vec, pg_vec);
3677                 rb->frame_max = (req->tp_frame_nr - 1);
3678                 rb->head = 0;
3679                 rb->frame_size = req->tp_frame_size;
3680                 spin_unlock_bh(&rb_queue->lock);
3681 
3682                 swap(rb->pg_vec_order, order);
3683                 swap(rb->pg_vec_len, req->tp_block_nr);
3684 
3685                 rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
3686                 po->prot_hook.func = (po->rx_ring.pg_vec) ?
3687                                                 tpacket_rcv : packet_rcv;
3688                 skb_queue_purge(rb_queue);
3689                 if (atomic_read(&po->mapped))
3690                         pr_err("packet_mmap: vma is busy: %d\n",
3691                                atomic_read(&po->mapped));
3692         }
3693         mutex_unlock(&po->pg_vec_lock);
3694 
3695         spin_lock(&po->bind_lock);
3696         if (was_running) {
3697                 po->num = num;
3698                 register_prot_hook(sk);
3699         }
3700         spin_unlock(&po->bind_lock);
3701         if (closing && (po->tp_version > TPACKET_V2)) {
3702                 /* Because we don't support block-based V3 on tx-ring */
3703                 if (!tx_ring)
3704                         prb_shutdown_retire_blk_timer(po, tx_ring, rb_queue);
3705         }
3706         release_sock(sk);
3707 
3708         if (pg_vec)
3709                 free_pg_vec(pg_vec, order, req->tp_block_nr);
3710 out:
3711         return err;
3712 }
3713 
3714 static int packet_mmap(struct file *file, struct socket *sock,
3715                 struct vm_area_struct *vma)
3716 {
3717         struct sock *sk = sock->sk;
3718         struct packet_sock *po = pkt_sk(sk);
3719         unsigned long size, expected_size;
3720         struct packet_ring_buffer *rb;
3721         unsigned long start;
3722         int err = -EINVAL;
3723         int i;
3724 
3725         if (vma->vm_pgoff)
3726                 return -EINVAL;
3727 
3728         mutex_lock(&po->pg_vec_lock);
3729 
3730         expected_size = 0;
3731         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
3732                 if (rb->pg_vec) {
3733                         expected_size += rb->pg_vec_len
3734                                                 * rb->pg_vec_pages
3735                                                 * PAGE_SIZE;
3736                 }
3737         }
3738 
3739         if (expected_size == 0)
3740                 goto out;
3741 
3742         size = vma->vm_end - vma->vm_start;
3743         if (size != expected_size)
3744                 goto out;
3745 
3746         start = vma->vm_start;
3747         for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
3748                 if (rb->pg_vec == NULL)
3749                         continue;
3750 
3751                 for (i = 0; i < rb->pg_vec_len; i++) {
3752                         struct page *page;
3753                         void *kaddr = rb->pg_vec[i].buffer;
3754                         int pg_num;
3755 
3756                         for (pg_num = 0; pg_num < rb->pg_vec_pages; pg_num++) {
3757                                 page = pgv_to_page(kaddr);
3758                                 err = vm_insert_page(vma, start, page);
3759                                 if (unlikely(err))
3760                                         goto out;
3761                                 start += PAGE_SIZE;
3762                                 kaddr += PAGE_SIZE;
3763                         }
3764                 }
3765         }
3766 
3767         atomic_inc(&po->mapped);
3768         vma->vm_ops = &packet_mmap_ops;
3769         err = 0;
3770 
3771 out:
3772         mutex_unlock(&po->pg_vec_lock);
3773         return err;
3774 }
3775 
3776 static const struct proto_ops packet_ops_spkt = {
3777         .family =       PF_PACKET,
3778         .owner =        THIS_MODULE,
3779         .release =      packet_release,
3780         .bind =         packet_bind_spkt,
3781         .connect =      sock_no_connect,
3782         .socketpair =   sock_no_socketpair,
3783         .accept =       sock_no_accept,
3784         .getname =      packet_getname_spkt,
3785         .poll =         datagram_poll,
3786         .ioctl =        packet_ioctl,
3787         .listen =       sock_no_listen,
3788         .shutdown =     sock_no_shutdown,
3789         .setsockopt =   sock_no_setsockopt,
3790         .getsockopt =   sock_no_getsockopt,
3791         .sendmsg =      packet_sendmsg_spkt,
3792         .recvmsg =      packet_recvmsg,
3793         .mmap =         sock_no_mmap,
3794         .sendpage =     sock_no_sendpage,
3795 };
3796 
3797 static const struct proto_ops packet_ops = {
3798         .family =       PF_PACKET,
3799         .owner =        THIS_MODULE,
3800         .release =      packet_release,
3801         .bind =         packet_bind,
3802         .connect =      sock_no_connect,
3803         .socketpair =   sock_no_socketpair,
3804         .accept =       sock_no_accept,
3805         .getname =      packet_getname,
3806         .poll =         packet_poll,
3807         .ioctl =        packet_ioctl,
3808         .listen =       sock_no_listen,
3809         .shutdown =     sock_no_shutdown,
3810         .setsockopt =   packet_setsockopt,
3811         .getsockopt =   packet_getsockopt,
3812         .sendmsg =      packet_sendmsg,
3813         .recvmsg =      packet_recvmsg,
3814         .mmap =         packet_mmap,
3815         .sendpage =     sock_no_sendpage,
3816 };
3817 
3818 static const struct net_proto_family packet_family_ops = {
3819         .family =       PF_PACKET,
3820         .create =       packet_create,
3821         .owner  =       THIS_MODULE,
3822 };
3823 
3824 static struct notifier_block packet_netdev_notifier = {
3825         .notifier_call =        packet_notifier,
3826 };
3827 
3828 #ifdef CONFIG_PROC_FS
3829 
3830 static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
3831         __acquires(RCU)
3832 {
3833         struct net *net = seq_file_net(seq);
3834 
3835         rcu_read_lock();
3836         return seq_hlist_start_head_rcu(&net->packet.sklist, *pos);
3837 }
3838 
3839 static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3840 {
3841         struct net *net = seq_file_net(seq);
3842         return seq_hlist_next_rcu(v, &net->packet.sklist, pos);
3843 }
3844 
3845 static void packet_seq_stop(struct seq_file *seq, void *v)
3846         __releases(RCU)
3847 {
3848         rcu_read_unlock();
3849 }
3850 
3851 static int packet_seq_show(struct seq_file *seq, void *v)
3852 {
3853         if (v == SEQ_START_TOKEN)
3854                 seq_puts(seq, "sk       RefCnt Type Proto  Iface R Rmem   User   Inode\n");
3855         else {
3856                 struct sock *s = sk_entry(v);
3857                 const struct packet_sock *po = pkt_sk(s);
3858 
3859                 seq_printf(seq,
3860                            "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
3861                            s,
3862                            atomic_read(&s->sk_refcnt),
3863                            s->sk_type,
3864                            ntohs(po->num),
3865                            po->ifindex,
3866                            po->running,
3867                            atomic_read(&s->sk_rmem_alloc),
3868                            from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
3869                            sock_i_ino(s));
3870         }
3871 
3872         return 0;
3873 }
3874 
3875 static const struct seq_operations packet_seq_ops = {
3876         .start  = packet_seq_start,
3877         .next   = packet_seq_next,
3878         .stop   = packet_seq_stop,
3879         .show   = packet_seq_show,
3880 };
3881 
3882 static int packet_seq_open(struct inode *inode, struct file *file)
3883 {
3884         return seq_open_net(inode, file, &packet_seq_ops,
3885                             sizeof(struct seq_net_private));
3886 }
3887 
3888 static const struct file_operations packet_seq_fops = {
3889         .owner          = THIS_MODULE,
3890         .open           = packet_seq_open,
3891         .read           = seq_read,
3892         .llseek         = seq_lseek,
3893         .release        = seq_release_net,
3894 };
3895 
3896 #endif
3897 
3898 static int __net_init packet_net_init(struct net *net)
3899 {
3900         mutex_init(&net->packet.sklist_lock);
3901         INIT_HLIST_HEAD(&net->packet.sklist);
3902 
3903         if (!proc_create("packet", 0, net->proc_net, &packet_seq_fops))
3904                 return -ENOMEM;
3905 
3906         return 0;
3907 }
3908 
3909 static void __net_exit packet_net_exit(struct net *net)
3910 {
3911         remove_proc_entry("packet", net->proc_net);
3912 }
3913 
3914 static struct pernet_operations packet_net_ops = {
3915         .init = packet_net_init,
3916         .exit = packet_net_exit,
3917 };
3918 
3919 
3920 static void __exit packet_exit(void)
3921 {
3922         unregister_netdevice_notifier(&packet_netdev_notifier);
3923         unregister_pernet_subsys(&packet_net_ops);
3924         sock_unregister(PF_PACKET);
3925         proto_unregister(&packet_proto);
3926 }
3927 
3928 static int __init packet_init(void)
3929 {
3930         int rc = proto_register(&packet_proto, 0);
3931 
3932         if (rc != 0)
3933                 goto out;
3934 
3935         sock_register(&packet_family_ops);
3936         register_pernet_subsys(&packet_net_ops);
3937         register_netdevice_notifier(&packet_netdev_notifier);
3938 out:
3939         return rc;
3940 }
3941 
3942 module_init(packet_init);
3943 module_exit(packet_exit);
3944 MODULE_LICENSE("GPL");
3945 MODULE_ALIAS_NETPROTO(PF_PACKET);
3946 

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