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TOMOYO Linux Cross Reference
Linux/net/ipv6/udp.c

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  1 /*
  2  *      UDP over IPv6
  3  *      Linux INET6 implementation
  4  *
  5  *      Authors:
  6  *      Pedro Roque             <roque@di.fc.ul.pt>
  7  *
  8  *      Based on linux/ipv4/udp.c
  9  *
 10  *      Fixes:
 11  *      Hideaki YOSHIFUJI       :       sin6_scope_id support
 12  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
 13  *      Alexey Kuznetsov                allow both IPv4 and IPv6 sockets to bind
 14  *                                      a single port at the same time.
 15  *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
 16  *      YOSHIFUJI Hideaki @USAGI:       convert /proc/net/udp6 to seq_file.
 17  *
 18  *      This program is free software; you can redistribute it and/or
 19  *      modify it under the terms of the GNU General Public License
 20  *      as published by the Free Software Foundation; either version
 21  *      2 of the License, or (at your option) any later version.
 22  */
 23 
 24 #include <linux/errno.h>
 25 #include <linux/types.h>
 26 #include <linux/socket.h>
 27 #include <linux/sockios.h>
 28 #include <linux/net.h>
 29 #include <linux/in6.h>
 30 #include <linux/netdevice.h>
 31 #include <linux/if_arp.h>
 32 #include <linux/ipv6.h>
 33 #include <linux/icmpv6.h>
 34 #include <linux/init.h>
 35 #include <linux/module.h>
 36 #include <linux/skbuff.h>
 37 #include <linux/slab.h>
 38 #include <linux/uaccess.h>
 39 
 40 #include <net/addrconf.h>
 41 #include <net/ndisc.h>
 42 #include <net/protocol.h>
 43 #include <net/transp_v6.h>
 44 #include <net/ip6_route.h>
 45 #include <net/raw.h>
 46 #include <net/tcp_states.h>
 47 #include <net/ip6_checksum.h>
 48 #include <net/xfrm.h>
 49 #include <net/inet_hashtables.h>
 50 #include <net/inet6_hashtables.h>
 51 #include <net/busy_poll.h>
 52 #include <net/sock_reuseport.h>
 53 
 54 #include <linux/proc_fs.h>
 55 #include <linux/seq_file.h>
 56 #include <trace/events/skb.h>
 57 #include "udp_impl.h"
 58 
 59 static bool udp6_lib_exact_dif_match(struct net *net, struct sk_buff *skb)
 60 {
 61 #if defined(CONFIG_NET_L3_MASTER_DEV)
 62         if (!net->ipv4.sysctl_udp_l3mdev_accept &&
 63             skb && ipv6_l3mdev_skb(IP6CB(skb)->flags))
 64                 return true;
 65 #endif
 66         return false;
 67 }
 68 
 69 static u32 udp6_ehashfn(const struct net *net,
 70                         const struct in6_addr *laddr,
 71                         const u16 lport,
 72                         const struct in6_addr *faddr,
 73                         const __be16 fport)
 74 {
 75         static u32 udp6_ehash_secret __read_mostly;
 76         static u32 udp_ipv6_hash_secret __read_mostly;
 77 
 78         u32 lhash, fhash;
 79 
 80         net_get_random_once(&udp6_ehash_secret,
 81                             sizeof(udp6_ehash_secret));
 82         net_get_random_once(&udp_ipv6_hash_secret,
 83                             sizeof(udp_ipv6_hash_secret));
 84 
 85         lhash = (__force u32)laddr->s6_addr32[3];
 86         fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
 87 
 88         return __inet6_ehashfn(lhash, lport, fhash, fport,
 89                                udp_ipv6_hash_secret + net_hash_mix(net));
 90 }
 91 
 92 int udp_v6_get_port(struct sock *sk, unsigned short snum)
 93 {
 94         unsigned int hash2_nulladdr =
 95                 ipv6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
 96         unsigned int hash2_partial =
 97                 ipv6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
 98 
 99         /* precompute partial secondary hash */
100         udp_sk(sk)->udp_portaddr_hash = hash2_partial;
101         return udp_lib_get_port(sk, snum, hash2_nulladdr);
102 }
103 
104 static void udp_v6_rehash(struct sock *sk)
105 {
106         u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
107                                           &sk->sk_v6_rcv_saddr,
108                                           inet_sk(sk)->inet_num);
109 
110         udp_lib_rehash(sk, new_hash);
111 }
112 
113 static int compute_score(struct sock *sk, struct net *net,
114                          const struct in6_addr *saddr, __be16 sport,
115                          const struct in6_addr *daddr, unsigned short hnum,
116                          int dif, int sdif, bool exact_dif)
117 {
118         int score;
119         struct inet_sock *inet;
120 
121         if (!net_eq(sock_net(sk), net) ||
122             udp_sk(sk)->udp_port_hash != hnum ||
123             sk->sk_family != PF_INET6)
124                 return -1;
125 
126         score = 0;
127         inet = inet_sk(sk);
128 
129         if (inet->inet_dport) {
130                 if (inet->inet_dport != sport)
131                         return -1;
132                 score++;
133         }
134 
135         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
136                 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
137                         return -1;
138                 score++;
139         }
140 
141         if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
142                 if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
143                         return -1;
144                 score++;
145         }
146 
147         if (sk->sk_bound_dev_if || exact_dif) {
148                 bool dev_match = (sk->sk_bound_dev_if == dif ||
149                                   sk->sk_bound_dev_if == sdif);
150 
151                 if (!dev_match)
152                         return -1;
153                 if (sk->sk_bound_dev_if)
154                         score++;
155         }
156 
157         if (sk->sk_incoming_cpu == raw_smp_processor_id())
158                 score++;
159 
160         return score;
161 }
162 
163 /* called with rcu_read_lock() */
164 static struct sock *udp6_lib_lookup2(struct net *net,
165                 const struct in6_addr *saddr, __be16 sport,
166                 const struct in6_addr *daddr, unsigned int hnum,
167                 int dif, int sdif, bool exact_dif,
168                 struct udp_hslot *hslot2, struct sk_buff *skb)
169 {
170         struct sock *sk, *result;
171         int score, badness;
172         u32 hash = 0;
173 
174         result = NULL;
175         badness = -1;
176         udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
177                 score = compute_score(sk, net, saddr, sport,
178                                       daddr, hnum, dif, sdif, exact_dif);
179                 if (score > badness) {
180                         if (sk->sk_reuseport) {
181                                 hash = udp6_ehashfn(net, daddr, hnum,
182                                                     saddr, sport);
183 
184                                 result = reuseport_select_sock(sk, hash, skb,
185                                                         sizeof(struct udphdr));
186                                 if (result)
187                                         return result;
188                         }
189                         result = sk;
190                         badness = score;
191                 }
192         }
193         return result;
194 }
195 
196 /* rcu_read_lock() must be held */
197 struct sock *__udp6_lib_lookup(struct net *net,
198                                const struct in6_addr *saddr, __be16 sport,
199                                const struct in6_addr *daddr, __be16 dport,
200                                int dif, int sdif, struct udp_table *udptable,
201                                struct sk_buff *skb)
202 {
203         struct sock *sk, *result;
204         unsigned short hnum = ntohs(dport);
205         unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
206         struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
207         bool exact_dif = udp6_lib_exact_dif_match(net, skb);
208         int score, badness;
209         u32 hash = 0;
210 
211         if (hslot->count > 10) {
212                 hash2 = ipv6_portaddr_hash(net, daddr, hnum);
213                 slot2 = hash2 & udptable->mask;
214                 hslot2 = &udptable->hash2[slot2];
215                 if (hslot->count < hslot2->count)
216                         goto begin;
217 
218                 result = udp6_lib_lookup2(net, saddr, sport,
219                                           daddr, hnum, dif, sdif, exact_dif,
220                                           hslot2, skb);
221                 if (!result) {
222                         unsigned int old_slot2 = slot2;
223                         hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
224                         slot2 = hash2 & udptable->mask;
225                         /* avoid searching the same slot again. */
226                         if (unlikely(slot2 == old_slot2))
227                                 return result;
228 
229                         hslot2 = &udptable->hash2[slot2];
230                         if (hslot->count < hslot2->count)
231                                 goto begin;
232 
233                         result = udp6_lib_lookup2(net, saddr, sport,
234                                                   daddr, hnum, dif, sdif,
235                                                   exact_dif, hslot2,
236                                                   skb);
237                 }
238                 return result;
239         }
240 begin:
241         result = NULL;
242         badness = -1;
243         sk_for_each_rcu(sk, &hslot->head) {
244                 score = compute_score(sk, net, saddr, sport, daddr, hnum, dif,
245                                       sdif, exact_dif);
246                 if (score > badness) {
247                         if (sk->sk_reuseport) {
248                                 hash = udp6_ehashfn(net, daddr, hnum,
249                                                     saddr, sport);
250                                 result = reuseport_select_sock(sk, hash, skb,
251                                                         sizeof(struct udphdr));
252                                 if (result)
253                                         return result;
254                         }
255                         result = sk;
256                         badness = score;
257                 }
258         }
259         return result;
260 }
261 EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
262 
263 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
264                                           __be16 sport, __be16 dport,
265                                           struct udp_table *udptable)
266 {
267         const struct ipv6hdr *iph = ipv6_hdr(skb);
268 
269         return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
270                                  &iph->daddr, dport, inet6_iif(skb),
271                                  inet6_sdif(skb), udptable, skb);
272 }
273 
274 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
275                                  __be16 sport, __be16 dport)
276 {
277         const struct ipv6hdr *iph = ipv6_hdr(skb);
278 
279         return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
280                                  &iph->daddr, dport, inet6_iif(skb),
281                                  inet6_sdif(skb), &udp_table, skb);
282 }
283 EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);
284 
285 /* Must be called under rcu_read_lock().
286  * Does increment socket refcount.
287  */
288 #if IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_SOCKET) || \
289     IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TPROXY) || \
290     IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
291 struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
292                              const struct in6_addr *daddr, __be16 dport, int dif)
293 {
294         struct sock *sk;
295 
296         sk =  __udp6_lib_lookup(net, saddr, sport, daddr, dport,
297                                 dif, 0, &udp_table, NULL);
298         if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
299                 sk = NULL;
300         return sk;
301 }
302 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
303 #endif
304 
305 /* do not use the scratch area len for jumbogram: their length execeeds the
306  * scratch area space; note that the IP6CB flags is still in the first
307  * cacheline, so checking for jumbograms is cheap
308  */
309 static int udp6_skb_len(struct sk_buff *skb)
310 {
311         return unlikely(inet6_is_jumbogram(skb)) ? skb->len : udp_skb_len(skb);
312 }
313 
314 /*
315  *      This should be easy, if there is something there we
316  *      return it, otherwise we block.
317  */
318 
319 int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
320                   int noblock, int flags, int *addr_len)
321 {
322         struct ipv6_pinfo *np = inet6_sk(sk);
323         struct inet_sock *inet = inet_sk(sk);
324         struct sk_buff *skb;
325         unsigned int ulen, copied;
326         int peeked, peeking, off;
327         int err;
328         int is_udplite = IS_UDPLITE(sk);
329         bool checksum_valid = false;
330         int is_udp4;
331 
332         if (flags & MSG_ERRQUEUE)
333                 return ipv6_recv_error(sk, msg, len, addr_len);
334 
335         if (np->rxpmtu && np->rxopt.bits.rxpmtu)
336                 return ipv6_recv_rxpmtu(sk, msg, len, addr_len);
337 
338 try_again:
339         peeking = flags & MSG_PEEK;
340         off = sk_peek_offset(sk, flags);
341         skb = __skb_recv_udp(sk, flags, noblock, &peeked, &off, &err);
342         if (!skb)
343                 return err;
344         if (ccs_socket_post_recvmsg_permission(sk, skb, flags))
345                 return -EAGAIN; /* Hope less harmful than -EPERM. */
346 
347         ulen = udp6_skb_len(skb);
348         copied = len;
349         if (copied > ulen - off)
350                 copied = ulen - off;
351         else if (copied < ulen)
352                 msg->msg_flags |= MSG_TRUNC;
353 
354         is_udp4 = (skb->protocol == htons(ETH_P_IP));
355 
356         /*
357          * If checksum is needed at all, try to do it while copying the
358          * data.  If the data is truncated, or if we only want a partial
359          * coverage checksum (UDP-Lite), do it before the copy.
360          */
361 
362         if (copied < ulen || peeking ||
363             (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
364                 checksum_valid = udp_skb_csum_unnecessary(skb) ||
365                                 !__udp_lib_checksum_complete(skb);
366                 if (!checksum_valid)
367                         goto csum_copy_err;
368         }
369 
370         if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
371                 if (udp_skb_is_linear(skb))
372                         err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
373                 else
374                         err = skb_copy_datagram_msg(skb, off, msg, copied);
375         } else {
376                 err = skb_copy_and_csum_datagram_msg(skb, off, msg);
377                 if (err == -EINVAL)
378                         goto csum_copy_err;
379         }
380         if (unlikely(err)) {
381                 if (!peeked) {
382                         atomic_inc(&sk->sk_drops);
383                         if (is_udp4)
384                                 UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
385                                               is_udplite);
386                         else
387                                 UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
388                                                is_udplite);
389                 }
390                 kfree_skb(skb);
391                 return err;
392         }
393         if (!peeked) {
394                 if (is_udp4)
395                         UDP_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
396                                       is_udplite);
397                 else
398                         UDP6_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
399                                        is_udplite);
400         }
401 
402         sock_recv_ts_and_drops(msg, sk, skb);
403 
404         /* Copy the address. */
405         if (msg->msg_name) {
406                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
407                 sin6->sin6_family = AF_INET6;
408                 sin6->sin6_port = udp_hdr(skb)->source;
409                 sin6->sin6_flowinfo = 0;
410 
411                 if (is_udp4) {
412                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
413                                                &sin6->sin6_addr);
414                         sin6->sin6_scope_id = 0;
415                 } else {
416                         sin6->sin6_addr = ipv6_hdr(skb)->saddr;
417                         sin6->sin6_scope_id =
418                                 ipv6_iface_scope_id(&sin6->sin6_addr,
419                                                     inet6_iif(skb));
420                 }
421                 *addr_len = sizeof(*sin6);
422         }
423 
424         if (np->rxopt.all)
425                 ip6_datagram_recv_common_ctl(sk, msg, skb);
426 
427         if (is_udp4) {
428                 if (inet->cmsg_flags)
429                         ip_cmsg_recv_offset(msg, sk, skb,
430                                             sizeof(struct udphdr), off);
431         } else {
432                 if (np->rxopt.all)
433                         ip6_datagram_recv_specific_ctl(sk, msg, skb);
434         }
435 
436         err = copied;
437         if (flags & MSG_TRUNC)
438                 err = ulen;
439 
440         skb_consume_udp(sk, skb, peeking ? -err : err);
441         return err;
442 
443 csum_copy_err:
444         if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
445                                  udp_skb_destructor)) {
446                 if (is_udp4) {
447                         UDP_INC_STATS(sock_net(sk),
448                                       UDP_MIB_CSUMERRORS, is_udplite);
449                         UDP_INC_STATS(sock_net(sk),
450                                       UDP_MIB_INERRORS, is_udplite);
451                 } else {
452                         UDP6_INC_STATS(sock_net(sk),
453                                        UDP_MIB_CSUMERRORS, is_udplite);
454                         UDP6_INC_STATS(sock_net(sk),
455                                        UDP_MIB_INERRORS, is_udplite);
456                 }
457         }
458         kfree_skb(skb);
459 
460         /* starting over for a new packet, but check if we need to yield */
461         cond_resched();
462         msg->msg_flags &= ~MSG_TRUNC;
463         goto try_again;
464 }
465 
466 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
467                     u8 type, u8 code, int offset, __be32 info,
468                     struct udp_table *udptable)
469 {
470         struct ipv6_pinfo *np;
471         const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
472         const struct in6_addr *saddr = &hdr->saddr;
473         const struct in6_addr *daddr = &hdr->daddr;
474         struct udphdr *uh = (struct udphdr *)(skb->data+offset);
475         struct sock *sk;
476         int harderr;
477         int err;
478         struct net *net = dev_net(skb->dev);
479 
480         sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
481                                inet6_iif(skb), 0, udptable, skb);
482         if (!sk) {
483                 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
484                                   ICMP6_MIB_INERRORS);
485                 return;
486         }
487 
488         harderr = icmpv6_err_convert(type, code, &err);
489         np = inet6_sk(sk);
490 
491         if (type == ICMPV6_PKT_TOOBIG) {
492                 if (!ip6_sk_accept_pmtu(sk))
493                         goto out;
494                 ip6_sk_update_pmtu(skb, sk, info);
495                 if (np->pmtudisc != IPV6_PMTUDISC_DONT)
496                         harderr = 1;
497         }
498         if (type == NDISC_REDIRECT) {
499                 ip6_sk_redirect(skb, sk);
500                 goto out;
501         }
502 
503         if (!np->recverr) {
504                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
505                         goto out;
506         } else {
507                 ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
508         }
509 
510         sk->sk_err = err;
511         sk->sk_error_report(sk);
512 out:
513         return;
514 }
515 
516 static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
517 {
518         int rc;
519 
520         if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
521                 sock_rps_save_rxhash(sk, skb);
522                 sk_mark_napi_id(sk, skb);
523                 sk_incoming_cpu_update(sk);
524         } else {
525                 sk_mark_napi_id_once(sk, skb);
526         }
527 
528         rc = __udp_enqueue_schedule_skb(sk, skb);
529         if (rc < 0) {
530                 int is_udplite = IS_UDPLITE(sk);
531 
532                 /* Note that an ENOMEM error is charged twice */
533                 if (rc == -ENOMEM)
534                         UDP6_INC_STATS(sock_net(sk),
535                                          UDP_MIB_RCVBUFERRORS, is_udplite);
536                 UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
537                 kfree_skb(skb);
538                 return -1;
539         }
540 
541         return 0;
542 }
543 
544 static __inline__ void udpv6_err(struct sk_buff *skb,
545                                  struct inet6_skb_parm *opt, u8 type,
546                                  u8 code, int offset, __be32 info)
547 {
548         __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
549 }
550 
551 static struct static_key udpv6_encap_needed __read_mostly;
552 void udpv6_encap_enable(void)
553 {
554         static_key_enable(&udpv6_encap_needed);
555 }
556 EXPORT_SYMBOL(udpv6_encap_enable);
557 
558 static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
559 {
560         struct udp_sock *up = udp_sk(sk);
561         int is_udplite = IS_UDPLITE(sk);
562 
563         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
564                 goto drop;
565 
566         if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
567                 int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
568 
569                 /*
570                  * This is an encapsulation socket so pass the skb to
571                  * the socket's udp_encap_rcv() hook. Otherwise, just
572                  * fall through and pass this up the UDP socket.
573                  * up->encap_rcv() returns the following value:
574                  * =0 if skb was successfully passed to the encap
575                  *    handler or was discarded by it.
576                  * >0 if skb should be passed on to UDP.
577                  * <0 if skb should be resubmitted as proto -N
578                  */
579 
580                 /* if we're overly short, let UDP handle it */
581                 encap_rcv = READ_ONCE(up->encap_rcv);
582                 if (encap_rcv) {
583                         int ret;
584 
585                         /* Verify checksum before giving to encap */
586                         if (udp_lib_checksum_complete(skb))
587                                 goto csum_error;
588 
589                         ret = encap_rcv(sk, skb);
590                         if (ret <= 0) {
591                                 __UDP_INC_STATS(sock_net(sk),
592                                                 UDP_MIB_INDATAGRAMS,
593                                                 is_udplite);
594                                 return -ret;
595                         }
596                 }
597 
598                 /* FALLTHROUGH -- it's a UDP Packet */
599         }
600 
601         /*
602          * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
603          */
604         if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
605 
606                 if (up->pcrlen == 0) {          /* full coverage was set  */
607                         net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
608                                             UDP_SKB_CB(skb)->cscov, skb->len);
609                         goto drop;
610                 }
611                 if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
612                         net_dbg_ratelimited("UDPLITE6: coverage %d too small, need min %d\n",
613                                             UDP_SKB_CB(skb)->cscov, up->pcrlen);
614                         goto drop;
615                 }
616         }
617 
618         prefetch(&sk->sk_rmem_alloc);
619         if (rcu_access_pointer(sk->sk_filter) &&
620             udp_lib_checksum_complete(skb))
621                 goto csum_error;
622 
623         if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
624                 goto drop;
625 
626         udp_csum_pull_header(skb);
627 
628         skb_dst_drop(skb);
629 
630         return __udpv6_queue_rcv_skb(sk, skb);
631 
632 csum_error:
633         __UDP6_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
634 drop:
635         __UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
636         atomic_inc(&sk->sk_drops);
637         kfree_skb(skb);
638         return -1;
639 }
640 
641 static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
642                                    __be16 loc_port, const struct in6_addr *loc_addr,
643                                    __be16 rmt_port, const struct in6_addr *rmt_addr,
644                                    int dif, unsigned short hnum)
645 {
646         struct inet_sock *inet = inet_sk(sk);
647 
648         if (!net_eq(sock_net(sk), net))
649                 return false;
650 
651         if (udp_sk(sk)->udp_port_hash != hnum ||
652             sk->sk_family != PF_INET6 ||
653             (inet->inet_dport && inet->inet_dport != rmt_port) ||
654             (!ipv6_addr_any(&sk->sk_v6_daddr) &&
655                     !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
656             (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif) ||
657             (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
658                     !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
659                 return false;
660         if (!inet6_mc_check(sk, loc_addr, rmt_addr))
661                 return false;
662         return true;
663 }
664 
665 static void udp6_csum_zero_error(struct sk_buff *skb)
666 {
667         /* RFC 2460 section 8.1 says that we SHOULD log
668          * this error. Well, it is reasonable.
669          */
670         net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
671                             &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
672                             &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
673 }
674 
675 /*
676  * Note: called only from the BH handler context,
677  * so we don't need to lock the hashes.
678  */
679 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
680                 const struct in6_addr *saddr, const struct in6_addr *daddr,
681                 struct udp_table *udptable, int proto)
682 {
683         struct sock *sk, *first = NULL;
684         const struct udphdr *uh = udp_hdr(skb);
685         unsigned short hnum = ntohs(uh->dest);
686         struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
687         unsigned int offset = offsetof(typeof(*sk), sk_node);
688         unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
689         int dif = inet6_iif(skb);
690         struct hlist_node *node;
691         struct sk_buff *nskb;
692 
693         if (use_hash2) {
694                 hash2_any = ipv6_portaddr_hash(net, &in6addr_any, hnum) &
695                             udptable->mask;
696                 hash2 = ipv6_portaddr_hash(net, daddr, hnum) & udptable->mask;
697 start_lookup:
698                 hslot = &udptable->hash2[hash2];
699                 offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
700         }
701 
702         sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
703                 if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr,
704                                             uh->source, saddr, dif, hnum))
705                         continue;
706                 /* If zero checksum and no_check is not on for
707                  * the socket then skip it.
708                  */
709                 if (!uh->check && !udp_sk(sk)->no_check6_rx)
710                         continue;
711                 if (!first) {
712                         first = sk;
713                         continue;
714                 }
715                 nskb = skb_clone(skb, GFP_ATOMIC);
716                 if (unlikely(!nskb)) {
717                         atomic_inc(&sk->sk_drops);
718                         __UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
719                                          IS_UDPLITE(sk));
720                         __UDP6_INC_STATS(net, UDP_MIB_INERRORS,
721                                          IS_UDPLITE(sk));
722                         continue;
723                 }
724 
725                 if (udpv6_queue_rcv_skb(sk, nskb) > 0)
726                         consume_skb(nskb);
727         }
728 
729         /* Also lookup *:port if we are using hash2 and haven't done so yet. */
730         if (use_hash2 && hash2 != hash2_any) {
731                 hash2 = hash2_any;
732                 goto start_lookup;
733         }
734 
735         if (first) {
736                 if (udpv6_queue_rcv_skb(first, skb) > 0)
737                         consume_skb(skb);
738         } else {
739                 kfree_skb(skb);
740                 __UDP6_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
741                                  proto == IPPROTO_UDPLITE);
742         }
743         return 0;
744 }
745 
746 static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
747 {
748         if (udp_sk_rx_dst_set(sk, dst)) {
749                 const struct rt6_info *rt = (const struct rt6_info *)dst;
750 
751                 inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
752         }
753 }
754 
755 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
756                    int proto)
757 {
758         const struct in6_addr *saddr, *daddr;
759         struct net *net = dev_net(skb->dev);
760         struct udphdr *uh;
761         struct sock *sk;
762         u32 ulen = 0;
763 
764         if (!pskb_may_pull(skb, sizeof(struct udphdr)))
765                 goto discard;
766 
767         saddr = &ipv6_hdr(skb)->saddr;
768         daddr = &ipv6_hdr(skb)->daddr;
769         uh = udp_hdr(skb);
770 
771         ulen = ntohs(uh->len);
772         if (ulen > skb->len)
773                 goto short_packet;
774 
775         if (proto == IPPROTO_UDP) {
776                 /* UDP validates ulen. */
777 
778                 /* Check for jumbo payload */
779                 if (ulen == 0)
780                         ulen = skb->len;
781 
782                 if (ulen < sizeof(*uh))
783                         goto short_packet;
784 
785                 if (ulen < skb->len) {
786                         if (pskb_trim_rcsum(skb, ulen))
787                                 goto short_packet;
788                         saddr = &ipv6_hdr(skb)->saddr;
789                         daddr = &ipv6_hdr(skb)->daddr;
790                         uh = udp_hdr(skb);
791                 }
792         }
793 
794         if (udp6_csum_init(skb, uh, proto))
795                 goto csum_error;
796 
797         /* Check if the socket is already available, e.g. due to early demux */
798         sk = skb_steal_sock(skb);
799         if (sk) {
800                 struct dst_entry *dst = skb_dst(skb);
801                 int ret;
802 
803                 if (unlikely(sk->sk_rx_dst != dst))
804                         udp6_sk_rx_dst_set(sk, dst);
805 
806                 ret = udpv6_queue_rcv_skb(sk, skb);
807                 sock_put(sk);
808 
809                 /* a return value > 0 means to resubmit the input */
810                 if (ret > 0)
811                         return ret;
812                 return 0;
813         }
814 
815         /*
816          *      Multicast receive code
817          */
818         if (ipv6_addr_is_multicast(daddr))
819                 return __udp6_lib_mcast_deliver(net, skb,
820                                 saddr, daddr, udptable, proto);
821 
822         /* Unicast */
823         sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
824         if (sk) {
825                 int ret;
826 
827                 if (!uh->check && !udp_sk(sk)->no_check6_rx) {
828                         udp6_csum_zero_error(skb);
829                         goto csum_error;
830                 }
831 
832                 if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
833                         skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
834                                                  ip6_compute_pseudo);
835 
836                 ret = udpv6_queue_rcv_skb(sk, skb);
837 
838                 /* a return value > 0 means to resubmit the input */
839                 if (ret > 0)
840                         return ret;
841 
842                 return 0;
843         }
844 
845         if (!uh->check) {
846                 udp6_csum_zero_error(skb);
847                 goto csum_error;
848         }
849 
850         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
851                 goto discard;
852 
853         if (udp_lib_checksum_complete(skb))
854                 goto csum_error;
855 
856         __UDP6_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
857         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
858 
859         kfree_skb(skb);
860         return 0;
861 
862 short_packet:
863         net_dbg_ratelimited("UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
864                             proto == IPPROTO_UDPLITE ? "-Lite" : "",
865                             saddr, ntohs(uh->source),
866                             ulen, skb->len,
867                             daddr, ntohs(uh->dest));
868         goto discard;
869 csum_error:
870         __UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
871 discard:
872         __UDP6_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
873         kfree_skb(skb);
874         return 0;
875 }
876 
877 
878 static struct sock *__udp6_lib_demux_lookup(struct net *net,
879                         __be16 loc_port, const struct in6_addr *loc_addr,
880                         __be16 rmt_port, const struct in6_addr *rmt_addr,
881                         int dif, int sdif)
882 {
883         unsigned short hnum = ntohs(loc_port);
884         unsigned int hash2 = ipv6_portaddr_hash(net, loc_addr, hnum);
885         unsigned int slot2 = hash2 & udp_table.mask;
886         struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
887         const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
888         struct sock *sk;
889 
890         udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
891                 if (sk->sk_state == TCP_ESTABLISHED &&
892                     INET6_MATCH(sk, net, rmt_addr, loc_addr, ports, dif, sdif))
893                         return sk;
894                 /* Only check first socket in chain */
895                 break;
896         }
897         return NULL;
898 }
899 
900 static void udp_v6_early_demux(struct sk_buff *skb)
901 {
902         struct net *net = dev_net(skb->dev);
903         const struct udphdr *uh;
904         struct sock *sk;
905         struct dst_entry *dst;
906         int dif = skb->dev->ifindex;
907         int sdif = inet6_sdif(skb);
908 
909         if (!pskb_may_pull(skb, skb_transport_offset(skb) +
910             sizeof(struct udphdr)))
911                 return;
912 
913         uh = udp_hdr(skb);
914 
915         if (skb->pkt_type == PACKET_HOST)
916                 sk = __udp6_lib_demux_lookup(net, uh->dest,
917                                              &ipv6_hdr(skb)->daddr,
918                                              uh->source, &ipv6_hdr(skb)->saddr,
919                                              dif, sdif);
920         else
921                 return;
922 
923         if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
924                 return;
925 
926         skb->sk = sk;
927         skb->destructor = sock_efree;
928         dst = READ_ONCE(sk->sk_rx_dst);
929 
930         if (dst)
931                 dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
932         if (dst) {
933                 /* set noref for now.
934                  * any place which wants to hold dst has to call
935                  * dst_hold_safe()
936                  */
937                 skb_dst_set_noref(skb, dst);
938         }
939 }
940 
941 static __inline__ int udpv6_rcv(struct sk_buff *skb)
942 {
943         return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
944 }
945 
946 /*
947  * Throw away all pending data and cancel the corking. Socket is locked.
948  */
949 static void udp_v6_flush_pending_frames(struct sock *sk)
950 {
951         struct udp_sock *up = udp_sk(sk);
952 
953         if (up->pending == AF_INET)
954                 udp_flush_pending_frames(sk);
955         else if (up->pending) {
956                 up->len = 0;
957                 up->pending = 0;
958                 ip6_flush_pending_frames(sk);
959         }
960 }
961 
962 static int udpv6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
963                              int addr_len)
964 {
965         /* The following checks are replicated from __ip6_datagram_connect()
966          * and intended to prevent BPF program called below from accessing
967          * bytes that are out of the bound specified by user in addr_len.
968          */
969         if (uaddr->sa_family == AF_INET) {
970                 if (__ipv6_only_sock(sk))
971                         return -EAFNOSUPPORT;
972                 return udp_pre_connect(sk, uaddr, addr_len);
973         }
974 
975         if (addr_len < SIN6_LEN_RFC2133)
976                 return -EINVAL;
977 
978         return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr);
979 }
980 
981 /**
982  *      udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
983  *      @sk:    socket we are sending on
984  *      @skb:   sk_buff containing the filled-in UDP header
985  *              (checksum field must be zeroed out)
986  */
987 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
988                                  const struct in6_addr *saddr,
989                                  const struct in6_addr *daddr, int len)
990 {
991         unsigned int offset;
992         struct udphdr *uh = udp_hdr(skb);
993         struct sk_buff *frags = skb_shinfo(skb)->frag_list;
994         __wsum csum = 0;
995 
996         if (!frags) {
997                 /* Only one fragment on the socket.  */
998                 skb->csum_start = skb_transport_header(skb) - skb->head;
999                 skb->csum_offset = offsetof(struct udphdr, check);
1000                 uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
1001         } else {
1002                 /*
1003                  * HW-checksum won't work as there are two or more
1004                  * fragments on the socket so that all csums of sk_buffs
1005                  * should be together
1006                  */
1007                 offset = skb_transport_offset(skb);
1008                 skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
1009                 csum = skb->csum;
1010 
1011                 skb->ip_summed = CHECKSUM_NONE;
1012 
1013                 do {
1014                         csum = csum_add(csum, frags->csum);
1015                 } while ((frags = frags->next));
1016 
1017                 uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
1018                                             csum);
1019                 if (uh->check == 0)
1020                         uh->check = CSUM_MANGLED_0;
1021         }
1022 }
1023 
1024 /*
1025  *      Sending
1026  */
1027 
1028 static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
1029 {
1030         struct sock *sk = skb->sk;
1031         struct udphdr *uh;
1032         int err = 0;
1033         int is_udplite = IS_UDPLITE(sk);
1034         __wsum csum = 0;
1035         int offset = skb_transport_offset(skb);
1036         int len = skb->len - offset;
1037 
1038         /*
1039          * Create a UDP header
1040          */
1041         uh = udp_hdr(skb);
1042         uh->source = fl6->fl6_sport;
1043         uh->dest = fl6->fl6_dport;
1044         uh->len = htons(len);
1045         uh->check = 0;
1046 
1047         if (is_udplite)
1048                 csum = udplite_csum(skb);
1049         else if (udp_sk(sk)->no_check6_tx) {   /* UDP csum disabled */
1050                 skb->ip_summed = CHECKSUM_NONE;
1051                 goto send;
1052         } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
1053                 udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
1054                 goto send;
1055         } else
1056                 csum = udp_csum(skb);
1057 
1058         /* add protocol-dependent pseudo-header */
1059         uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
1060                                     len, fl6->flowi6_proto, csum);
1061         if (uh->check == 0)
1062                 uh->check = CSUM_MANGLED_0;
1063 
1064 send:
1065         err = ip6_send_skb(skb);
1066         if (err) {
1067                 if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
1068                         UDP6_INC_STATS(sock_net(sk),
1069                                        UDP_MIB_SNDBUFERRORS, is_udplite);
1070                         err = 0;
1071                 }
1072         } else {
1073                 UDP6_INC_STATS(sock_net(sk),
1074                                UDP_MIB_OUTDATAGRAMS, is_udplite);
1075         }
1076         return err;
1077 }
1078 
1079 static int udp_v6_push_pending_frames(struct sock *sk)
1080 {
1081         struct sk_buff *skb;
1082         struct udp_sock  *up = udp_sk(sk);
1083         struct flowi6 fl6;
1084         int err = 0;
1085 
1086         if (up->pending == AF_INET)
1087                 return udp_push_pending_frames(sk);
1088 
1089         /* ip6_finish_skb will release the cork, so make a copy of
1090          * fl6 here.
1091          */
1092         fl6 = inet_sk(sk)->cork.fl.u.ip6;
1093 
1094         skb = ip6_finish_skb(sk);
1095         if (!skb)
1096                 goto out;
1097 
1098         err = udp_v6_send_skb(skb, &fl6);
1099 
1100 out:
1101         up->len = 0;
1102         up->pending = 0;
1103         return err;
1104 }
1105 
1106 int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1107 {
1108         struct ipv6_txoptions opt_space;
1109         struct udp_sock *up = udp_sk(sk);
1110         struct inet_sock *inet = inet_sk(sk);
1111         struct ipv6_pinfo *np = inet6_sk(sk);
1112         DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
1113         struct in6_addr *daddr, *final_p, final;
1114         struct ipv6_txoptions *opt = NULL;
1115         struct ipv6_txoptions *opt_to_free = NULL;
1116         struct ip6_flowlabel *flowlabel = NULL;
1117         struct flowi6 fl6;
1118         struct dst_entry *dst;
1119         struct ipcm6_cookie ipc6;
1120         int addr_len = msg->msg_namelen;
1121         bool connected = false;
1122         int ulen = len;
1123         int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
1124         int err;
1125         int is_udplite = IS_UDPLITE(sk);
1126         int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1127         struct sockcm_cookie sockc;
1128 
1129         ipc6.hlimit = -1;
1130         ipc6.tclass = -1;
1131         ipc6.dontfrag = -1;
1132         sockc.tsflags = sk->sk_tsflags;
1133 
1134         /* destination address check */
1135         if (sin6) {
1136                 if (addr_len < offsetof(struct sockaddr, sa_data))
1137                         return -EINVAL;
1138 
1139                 switch (sin6->sin6_family) {
1140                 case AF_INET6:
1141                         if (addr_len < SIN6_LEN_RFC2133)
1142                                 return -EINVAL;
1143                         daddr = &sin6->sin6_addr;
1144                         if (ipv6_addr_any(daddr) &&
1145                             ipv6_addr_v4mapped(&np->saddr))
1146                                 ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
1147                                                        daddr);
1148                         break;
1149                 case AF_INET:
1150                         goto do_udp_sendmsg;
1151                 case AF_UNSPEC:
1152                         msg->msg_name = sin6 = NULL;
1153                         msg->msg_namelen = addr_len = 0;
1154                         daddr = NULL;
1155                         break;
1156                 default:
1157                         return -EINVAL;
1158                 }
1159         } else if (!up->pending) {
1160                 if (sk->sk_state != TCP_ESTABLISHED)
1161                         return -EDESTADDRREQ;
1162                 daddr = &sk->sk_v6_daddr;
1163         } else
1164                 daddr = NULL;
1165 
1166         if (daddr) {
1167                 if (ipv6_addr_v4mapped(daddr)) {
1168                         struct sockaddr_in sin;
1169                         sin.sin_family = AF_INET;
1170                         sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1171                         sin.sin_addr.s_addr = daddr->s6_addr32[3];
1172                         msg->msg_name = &sin;
1173                         msg->msg_namelen = sizeof(sin);
1174 do_udp_sendmsg:
1175                         if (__ipv6_only_sock(sk))
1176                                 return -ENETUNREACH;
1177                         return udp_sendmsg(sk, msg, len);
1178                 }
1179         }
1180 
1181         if (up->pending == AF_INET)
1182                 return udp_sendmsg(sk, msg, len);
1183 
1184         /* Rough check on arithmetic overflow,
1185            better check is made in ip6_append_data().
1186            */
1187         if (len > INT_MAX - sizeof(struct udphdr))
1188                 return -EMSGSIZE;
1189 
1190         getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1191         if (up->pending) {
1192                 /*
1193                  * There are pending frames.
1194                  * The socket lock must be held while it's corked.
1195                  */
1196                 lock_sock(sk);
1197                 if (likely(up->pending)) {
1198                         if (unlikely(up->pending != AF_INET6)) {
1199                                 release_sock(sk);
1200                                 return -EAFNOSUPPORT;
1201                         }
1202                         dst = NULL;
1203                         goto do_append_data;
1204                 }
1205                 release_sock(sk);
1206         }
1207         ulen += sizeof(struct udphdr);
1208 
1209         memset(&fl6, 0, sizeof(fl6));
1210 
1211         if (sin6) {
1212                 if (sin6->sin6_port == 0)
1213                         return -EINVAL;
1214 
1215                 fl6.fl6_dport = sin6->sin6_port;
1216                 daddr = &sin6->sin6_addr;
1217 
1218                 if (np->sndflow) {
1219                         fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1220                         if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1221                                 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1222                                 if (!flowlabel)
1223                                         return -EINVAL;
1224                         }
1225                 }
1226 
1227                 /*
1228                  * Otherwise it will be difficult to maintain
1229                  * sk->sk_dst_cache.
1230                  */
1231                 if (sk->sk_state == TCP_ESTABLISHED &&
1232                     ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
1233                         daddr = &sk->sk_v6_daddr;
1234 
1235                 if (addr_len >= sizeof(struct sockaddr_in6) &&
1236                     sin6->sin6_scope_id &&
1237                     __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
1238                         fl6.flowi6_oif = sin6->sin6_scope_id;
1239         } else {
1240                 if (sk->sk_state != TCP_ESTABLISHED)
1241                         return -EDESTADDRREQ;
1242 
1243                 fl6.fl6_dport = inet->inet_dport;
1244                 daddr = &sk->sk_v6_daddr;
1245                 fl6.flowlabel = np->flow_label;
1246                 connected = true;
1247         }
1248 
1249         if (!fl6.flowi6_oif)
1250                 fl6.flowi6_oif = sk->sk_bound_dev_if;
1251 
1252         if (!fl6.flowi6_oif)
1253                 fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1254 
1255         fl6.flowi6_mark = sk->sk_mark;
1256         fl6.flowi6_uid = sk->sk_uid;
1257 
1258         if (msg->msg_controllen) {
1259                 opt = &opt_space;
1260                 memset(opt, 0, sizeof(struct ipv6_txoptions));
1261                 opt->tot_len = sizeof(*opt);
1262                 ipc6.opt = opt;
1263 
1264                 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6, &sockc);
1265                 if (err < 0) {
1266                         fl6_sock_release(flowlabel);
1267                         return err;
1268                 }
1269                 if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1270                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1271                         if (!flowlabel)
1272                                 return -EINVAL;
1273                 }
1274                 if (!(opt->opt_nflen|opt->opt_flen))
1275                         opt = NULL;
1276                 connected = false;
1277         }
1278         if (!opt) {
1279                 opt = txopt_get(np);
1280                 opt_to_free = opt;
1281         }
1282         if (flowlabel)
1283                 opt = fl6_merge_options(&opt_space, flowlabel, opt);
1284         opt = ipv6_fixup_options(&opt_space, opt);
1285         ipc6.opt = opt;
1286 
1287         fl6.flowi6_proto = sk->sk_protocol;
1288         if (!ipv6_addr_any(daddr))
1289                 fl6.daddr = *daddr;
1290         else
1291                 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1292         if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1293                 fl6.saddr = np->saddr;
1294         fl6.fl6_sport = inet->inet_sport;
1295 
1296         final_p = fl6_update_dst(&fl6, opt, &final);
1297         if (final_p)
1298                 connected = false;
1299 
1300         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1301                 fl6.flowi6_oif = np->mcast_oif;
1302                 connected = false;
1303         } else if (!fl6.flowi6_oif)
1304                 fl6.flowi6_oif = np->ucast_oif;
1305 
1306         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1307 
1308         if (ipc6.tclass < 0)
1309                 ipc6.tclass = np->tclass;
1310 
1311         fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
1312 
1313         dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p, connected);
1314         if (IS_ERR(dst)) {
1315                 err = PTR_ERR(dst);
1316                 dst = NULL;
1317                 goto out;
1318         }
1319 
1320         if (ipc6.hlimit < 0)
1321                 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
1322 
1323         if (msg->msg_flags&MSG_CONFIRM)
1324                 goto do_confirm;
1325 back_from_confirm:
1326 
1327         /* Lockless fast path for the non-corking case */
1328         if (!corkreq) {
1329                 struct sk_buff *skb;
1330 
1331                 skb = ip6_make_skb(sk, getfrag, msg, ulen,
1332                                    sizeof(struct udphdr), &ipc6,
1333                                    &fl6, (struct rt6_info *)dst,
1334                                    msg->msg_flags, &sockc);
1335                 err = PTR_ERR(skb);
1336                 if (!IS_ERR_OR_NULL(skb))
1337                         err = udp_v6_send_skb(skb, &fl6);
1338                 goto out;
1339         }
1340 
1341         lock_sock(sk);
1342         if (unlikely(up->pending)) {
1343                 /* The socket is already corked while preparing it. */
1344                 /* ... which is an evident application bug. --ANK */
1345                 release_sock(sk);
1346 
1347                 net_dbg_ratelimited("udp cork app bug 2\n");
1348                 err = -EINVAL;
1349                 goto out;
1350         }
1351 
1352         up->pending = AF_INET6;
1353 
1354 do_append_data:
1355         if (ipc6.dontfrag < 0)
1356                 ipc6.dontfrag = np->dontfrag;
1357         up->len += ulen;
1358         err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr),
1359                               &ipc6, &fl6, (struct rt6_info *)dst,
1360                               corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, &sockc);
1361         if (err)
1362                 udp_v6_flush_pending_frames(sk);
1363         else if (!corkreq)
1364                 err = udp_v6_push_pending_frames(sk);
1365         else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1366                 up->pending = 0;
1367 
1368         if (err > 0)
1369                 err = np->recverr ? net_xmit_errno(err) : 0;
1370         release_sock(sk);
1371 
1372 out:
1373         dst_release(dst);
1374         fl6_sock_release(flowlabel);
1375         txopt_put(opt_to_free);
1376         if (!err)
1377                 return len;
1378         /*
1379          * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1380          * ENOBUFS might not be good (it's not tunable per se), but otherwise
1381          * we don't have a good statistic (IpOutDiscards but it can be too many
1382          * things).  We could add another new stat but at least for now that
1383          * seems like overkill.
1384          */
1385         if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1386                 UDP6_INC_STATS(sock_net(sk),
1387                                UDP_MIB_SNDBUFERRORS, is_udplite);
1388         }
1389         return err;
1390 
1391 do_confirm:
1392         if (msg->msg_flags & MSG_PROBE)
1393                 dst_confirm_neigh(dst, &fl6.daddr);
1394         if (!(msg->msg_flags&MSG_PROBE) || len)
1395                 goto back_from_confirm;
1396         err = 0;
1397         goto out;
1398 }
1399 
1400 void udpv6_destroy_sock(struct sock *sk)
1401 {
1402         struct udp_sock *up = udp_sk(sk);
1403         lock_sock(sk);
1404         udp_v6_flush_pending_frames(sk);
1405         release_sock(sk);
1406 
1407         if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
1408                 void (*encap_destroy)(struct sock *sk);
1409                 encap_destroy = READ_ONCE(up->encap_destroy);
1410                 if (encap_destroy)
1411                         encap_destroy(sk);
1412         }
1413 
1414         inet6_destroy_sock(sk);
1415 }
1416 
1417 /*
1418  *      Socket option code for UDP
1419  */
1420 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1421                      char __user *optval, unsigned int optlen)
1422 {
1423         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1424                 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1425                                           udp_v6_push_pending_frames);
1426         return ipv6_setsockopt(sk, level, optname, optval, optlen);
1427 }
1428 
1429 #ifdef CONFIG_COMPAT
1430 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1431                             char __user *optval, unsigned int optlen)
1432 {
1433         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1434                 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1435                                           udp_v6_push_pending_frames);
1436         return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1437 }
1438 #endif
1439 
1440 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1441                      char __user *optval, int __user *optlen)
1442 {
1443         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1444                 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1445         return ipv6_getsockopt(sk, level, optname, optval, optlen);
1446 }
1447 
1448 #ifdef CONFIG_COMPAT
1449 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1450                             char __user *optval, int __user *optlen)
1451 {
1452         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1453                 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1454         return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1455 }
1456 #endif
1457 
1458 /* thinking of making this const? Don't.
1459  * early_demux can change based on sysctl.
1460  */
1461 static struct inet6_protocol udpv6_protocol = {
1462         .early_demux    =       udp_v6_early_demux,
1463         .early_demux_handler =  udp_v6_early_demux,
1464         .handler        =       udpv6_rcv,
1465         .err_handler    =       udpv6_err,
1466         .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1467 };
1468 
1469 /* ------------------------------------------------------------------------ */
1470 #ifdef CONFIG_PROC_FS
1471 int udp6_seq_show(struct seq_file *seq, void *v)
1472 {
1473         if (v == SEQ_START_TOKEN) {
1474                 seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1475         } else {
1476                 int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1477                 struct inet_sock *inet = inet_sk(v);
1478                 __u16 srcp = ntohs(inet->inet_sport);
1479                 __u16 destp = ntohs(inet->inet_dport);
1480                 __ip6_dgram_sock_seq_show(seq, v, srcp, destp,
1481                                           udp_rqueue_get(v), bucket);
1482         }
1483         return 0;
1484 }
1485 
1486 static const struct file_operations udp6_afinfo_seq_fops = {
1487         .open     = udp_seq_open,
1488         .read     = seq_read,
1489         .llseek   = seq_lseek,
1490         .release  = seq_release_net
1491 };
1492 
1493 static struct udp_seq_afinfo udp6_seq_afinfo = {
1494         .name           = "udp6",
1495         .family         = AF_INET6,
1496         .udp_table      = &udp_table,
1497         .seq_fops       = &udp6_afinfo_seq_fops,
1498         .seq_ops        = {
1499                 .show           = udp6_seq_show,
1500         },
1501 };
1502 
1503 int __net_init udp6_proc_init(struct net *net)
1504 {
1505         return udp_proc_register(net, &udp6_seq_afinfo);
1506 }
1507 
1508 void udp6_proc_exit(struct net *net)
1509 {
1510         udp_proc_unregister(net, &udp6_seq_afinfo);
1511 }
1512 #endif /* CONFIG_PROC_FS */
1513 
1514 /* ------------------------------------------------------------------------ */
1515 
1516 struct proto udpv6_prot = {
1517         .name                   = "UDPv6",
1518         .owner                  = THIS_MODULE,
1519         .close                  = udp_lib_close,
1520         .pre_connect            = udpv6_pre_connect,
1521         .connect                = ip6_datagram_connect,
1522         .disconnect             = udp_disconnect,
1523         .ioctl                  = udp_ioctl,
1524         .init                   = udp_init_sock,
1525         .destroy                = udpv6_destroy_sock,
1526         .setsockopt             = udpv6_setsockopt,
1527         .getsockopt             = udpv6_getsockopt,
1528         .sendmsg                = udpv6_sendmsg,
1529         .recvmsg                = udpv6_recvmsg,
1530         .release_cb             = ip6_datagram_release_cb,
1531         .hash                   = udp_lib_hash,
1532         .unhash                 = udp_lib_unhash,
1533         .rehash                 = udp_v6_rehash,
1534         .get_port               = udp_v6_get_port,
1535         .memory_allocated       = &udp_memory_allocated,
1536         .sysctl_mem             = sysctl_udp_mem,
1537         .sysctl_wmem_offset     = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
1538         .sysctl_rmem_offset     = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
1539         .obj_size               = sizeof(struct udp6_sock),
1540         .h.udp_table            = &udp_table,
1541 #ifdef CONFIG_COMPAT
1542         .compat_setsockopt      = compat_udpv6_setsockopt,
1543         .compat_getsockopt      = compat_udpv6_getsockopt,
1544 #endif
1545         .diag_destroy           = udp_abort,
1546 };
1547 
1548 static struct inet_protosw udpv6_protosw = {
1549         .type =      SOCK_DGRAM,
1550         .protocol =  IPPROTO_UDP,
1551         .prot =      &udpv6_prot,
1552         .ops =       &inet6_dgram_ops,
1553         .flags =     INET_PROTOSW_PERMANENT,
1554 };
1555 
1556 int __init udpv6_init(void)
1557 {
1558         int ret;
1559 
1560         ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1561         if (ret)
1562                 goto out;
1563 
1564         ret = inet6_register_protosw(&udpv6_protosw);
1565         if (ret)
1566                 goto out_udpv6_protocol;
1567 out:
1568         return ret;
1569 
1570 out_udpv6_protocol:
1571         inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1572         goto out;
1573 }
1574 
1575 void udpv6_exit(void)
1576 {
1577         inet6_unregister_protosw(&udpv6_protosw);
1578         inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1579 }
1580 

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