Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/net/ipv4/udp.c

  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  *              The User Datagram Protocol (UDP).
  7  *
  8  * Authors:     Ross Biro
  9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 10  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 11  *              Alan Cox, <alan@lxorguk.ukuu.org.uk>
 12  *              Hirokazu Takahashi, <taka@valinux.co.jp>
 13  *
 14  * Fixes:
 15  *              Alan Cox        :       verify_area() calls
 16  *              Alan Cox        :       stopped close while in use off icmp
 17  *                                      messages. Not a fix but a botch that
 18  *                                      for udp at least is 'valid'.
 19  *              Alan Cox        :       Fixed icmp handling properly
 20  *              Alan Cox        :       Correct error for oversized datagrams
 21  *              Alan Cox        :       Tidied select() semantics.
 22  *              Alan Cox        :       udp_err() fixed properly, also now
 23  *                                      select and read wake correctly on errors
 24  *              Alan Cox        :       udp_send verify_area moved to avoid mem leak
 25  *              Alan Cox        :       UDP can count its memory
 26  *              Alan Cox        :       send to an unknown connection causes
 27  *                                      an ECONNREFUSED off the icmp, but
 28  *                                      does NOT close.
 29  *              Alan Cox        :       Switched to new sk_buff handlers. No more backlog!
 30  *              Alan Cox        :       Using generic datagram code. Even smaller and the PEEK
 31  *                                      bug no longer crashes it.
 32  *              Fred Van Kempen :       Net2e support for sk->broadcast.
 33  *              Alan Cox        :       Uses skb_free_datagram
 34  *              Alan Cox        :       Added get/set sockopt support.
 35  *              Alan Cox        :       Broadcasting without option set returns EACCES.
 36  *              Alan Cox        :       No wakeup calls. Instead we now use the callbacks.
 37  *              Alan Cox        :       Use ip_tos and ip_ttl
 38  *              Alan Cox        :       SNMP Mibs
 39  *              Alan Cox        :       MSG_DONTROUTE, and 0.0.0.0 support.
 40  *              Matt Dillon     :       UDP length checks.
 41  *              Alan Cox        :       Smarter af_inet used properly.
 42  *              Alan Cox        :       Use new kernel side addressing.
 43  *              Alan Cox        :       Incorrect return on truncated datagram receive.
 44  *      Arnt Gulbrandsen        :       New udp_send and stuff
 45  *              Alan Cox        :       Cache last socket
 46  *              Alan Cox        :       Route cache
 47  *              Jon Peatfield   :       Minor efficiency fix to sendto().
 48  *              Mike Shaver     :       RFC1122 checks.
 49  *              Alan Cox        :       Nonblocking error fix.
 50  *      Willy Konynenberg       :       Transparent proxying support.
 51  *              Mike McLagan    :       Routing by source
 52  *              David S. Miller :       New socket lookup architecture.
 53  *                                      Last socket cache retained as it
 54  *                                      does have a high hit rate.
 55  *              Olaf Kirch      :       Don't linearise iovec on sendmsg.
 56  *              Andi Kleen      :       Some cleanups, cache destination entry
 57  *                                      for connect.
 58  *      Vitaly E. Lavrov        :       Transparent proxy revived after year coma.
 59  *              Melvin Smith    :       Check msg_name not msg_namelen in sendto(),
 60  *                                      return ENOTCONN for unconnected sockets (POSIX)
 61  *              Janos Farkas    :       don't deliver multi/broadcasts to a different
 62  *                                      bound-to-device socket
 63  *      Hirokazu Takahashi      :       HW checksumming for outgoing UDP
 64  *                                      datagrams.
 65  *      Hirokazu Takahashi      :       sendfile() on UDP works now.
 66  *              Arnaldo C. Melo :       convert /proc/net/udp to seq_file
 67  *      YOSHIFUJI Hideaki @USAGI and:   Support IPV6_V6ONLY socket option, which
 68  *      Alexey Kuznetsov:               allow both IPv4 and IPv6 sockets to bind
 69  *                                      a single port at the same time.
 70  *      Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
 71  *      James Chapman           :       Add L2TP encapsulation type.
 72  *
 73  *
 74  *              This program is free software; you can redistribute it and/or
 75  *              modify it under the terms of the GNU General Public License
 76  *              as published by the Free Software Foundation; either version
 77  *              2 of the License, or (at your option) any later version.
 78  */
 79 
 80 #define pr_fmt(fmt) "UDP: " fmt
 81 
 82 #include <asm/uaccess.h>
 83 #include <asm/ioctls.h>
 84 #include <linux/bootmem.h>
 85 #include <linux/highmem.h>
 86 #include <linux/swap.h>
 87 #include <linux/types.h>
 88 #include <linux/fcntl.h>
 89 #include <linux/module.h>
 90 #include <linux/socket.h>
 91 #include <linux/sockios.h>
 92 #include <linux/igmp.h>
 93 #include <linux/in.h>
 94 #include <linux/errno.h>
 95 #include <linux/timer.h>
 96 #include <linux/mm.h>
 97 #include <linux/inet.h>
 98 #include <linux/netdevice.h>
 99 #include <linux/slab.h>
100 #include <net/tcp_states.h>
101 #include <linux/skbuff.h>
102 #include <linux/netdevice.h>
103 #include <linux/proc_fs.h>
104 #include <linux/seq_file.h>
105 #include <net/net_namespace.h>
106 #include <net/icmp.h>
107 #include <net/inet_hashtables.h>
108 #include <net/route.h>
109 #include <net/checksum.h>
110 #include <net/xfrm.h>
111 #include <trace/events/udp.h>
112 #include <linux/static_key.h>
113 #include <trace/events/skb.h>
114 #include <net/busy_poll.h>
115 #include "udp_impl.h"
116 
117 struct udp_table udp_table __read_mostly;
118 EXPORT_SYMBOL(udp_table);
119 
120 long sysctl_udp_mem[3] __read_mostly;
121 EXPORT_SYMBOL(sysctl_udp_mem);
122 
123 int sysctl_udp_rmem_min __read_mostly;
124 EXPORT_SYMBOL(sysctl_udp_rmem_min);
125 
126 int sysctl_udp_wmem_min __read_mostly;
127 EXPORT_SYMBOL(sysctl_udp_wmem_min);
128 
129 atomic_long_t udp_memory_allocated;
130 EXPORT_SYMBOL(udp_memory_allocated);
131 
132 #define MAX_UDP_PORTS 65536
133 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
134 
135 static int udp_lib_lport_inuse(struct net *net, __u16 num,
136                                const struct udp_hslot *hslot,
137                                unsigned long *bitmap,
138                                struct sock *sk,
139                                int (*saddr_comp)(const struct sock *sk1,
140                                                  const struct sock *sk2),
141                                unsigned int log)
142 {
143         struct sock *sk2;
144         struct hlist_nulls_node *node;
145         kuid_t uid = sock_i_uid(sk);
146 
147         sk_nulls_for_each(sk2, node, &hslot->head) {
148                 if (net_eq(sock_net(sk2), net) &&
149                     sk2 != sk &&
150                     (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
151                     (!sk2->sk_reuse || !sk->sk_reuse) &&
152                     (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
153                      sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
154                     (!sk2->sk_reuseport || !sk->sk_reuseport ||
155                      !uid_eq(uid, sock_i_uid(sk2))) &&
156                     saddr_comp(sk, sk2)) {
157                         if (!bitmap)
158                                 return 1;
159                         __set_bit(udp_sk(sk2)->udp_port_hash >> log, bitmap);
160                 }
161         }
162         return 0;
163 }
164 
165 /*
166  * Note: we still hold spinlock of primary hash chain, so no other writer
167  * can insert/delete a socket with local_port == num
168  */
169 static int udp_lib_lport_inuse2(struct net *net, __u16 num,
170                                 struct udp_hslot *hslot2,
171                                 struct sock *sk,
172                                 int (*saddr_comp)(const struct sock *sk1,
173                                                   const struct sock *sk2))
174 {
175         struct sock *sk2;
176         struct hlist_nulls_node *node;
177         kuid_t uid = sock_i_uid(sk);
178         int res = 0;
179 
180         spin_lock(&hslot2->lock);
181         udp_portaddr_for_each_entry(sk2, node, &hslot2->head) {
182                 if (net_eq(sock_net(sk2), net) &&
183                     sk2 != sk &&
184                     (udp_sk(sk2)->udp_port_hash == num) &&
185                     (!sk2->sk_reuse || !sk->sk_reuse) &&
186                     (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
187                      sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
188                     (!sk2->sk_reuseport || !sk->sk_reuseport ||
189                      !uid_eq(uid, sock_i_uid(sk2))) &&
190                     saddr_comp(sk, sk2)) {
191                         res = 1;
192                         break;
193                 }
194         }
195         spin_unlock(&hslot2->lock);
196         return res;
197 }
198 
199 /**
200  *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
201  *
202  *  @sk:          socket struct in question
203  *  @snum:        port number to look up
204  *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
205  *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
206  *                   with NULL address
207  */
208 int udp_lib_get_port(struct sock *sk, unsigned short snum,
209                      int (*saddr_comp)(const struct sock *sk1,
210                                        const struct sock *sk2),
211                      unsigned int hash2_nulladdr)
212 {
213         struct udp_hslot *hslot, *hslot2;
214         struct udp_table *udptable = sk->sk_prot->h.udp_table;
215         int    error = 1;
216         struct net *net = sock_net(sk);
217 
218         if (!snum) {
219                 int low, high, remaining;
220                 unsigned int rand;
221                 unsigned short first, last;
222                 DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
223 
224                 inet_get_local_port_range(net, &low, &high);
225                 remaining = (high - low) + 1;
226 
227                 rand = prandom_u32();
228                 first = reciprocal_scale(rand, remaining) + low;
229                 /*
230                  * force rand to be an odd multiple of UDP_HTABLE_SIZE
231                  */
232                 rand = (rand | 1) * (udptable->mask + 1);
233                 last = first + udptable->mask + 1;
234                 do {
235                         hslot = udp_hashslot(udptable, net, first);
236                         bitmap_zero(bitmap, PORTS_PER_CHAIN);
237                         spin_lock_bh(&hslot->lock);
238                         udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
239                                             saddr_comp, udptable->log);
240 
241                         snum = first;
242                         /*
243                          * Iterate on all possible values of snum for this hash.
244                          * Using steps of an odd multiple of UDP_HTABLE_SIZE
245                          * give us randomization and full range coverage.
246                          */
247                         do {
248                                 if (low <= snum && snum <= high &&
249                                     !test_bit(snum >> udptable->log, bitmap) &&
250                                     !inet_is_local_reserved_port(net, snum))
251                                         goto found;
252                                 snum += rand;
253                         } while (snum != first);
254                         spin_unlock_bh(&hslot->lock);
255                 } while (++first != last);
256                 goto fail;
257         } else {
258                 hslot = udp_hashslot(udptable, net, snum);
259                 spin_lock_bh(&hslot->lock);
260                 if (hslot->count > 10) {
261                         int exist;
262                         unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
263 
264                         slot2          &= udptable->mask;
265                         hash2_nulladdr &= udptable->mask;
266 
267                         hslot2 = udp_hashslot2(udptable, slot2);
268                         if (hslot->count < hslot2->count)
269                                 goto scan_primary_hash;
270 
271                         exist = udp_lib_lport_inuse2(net, snum, hslot2,
272                                                      sk, saddr_comp);
273                         if (!exist && (hash2_nulladdr != slot2)) {
274                                 hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
275                                 exist = udp_lib_lport_inuse2(net, snum, hslot2,
276                                                              sk, saddr_comp);
277                         }
278                         if (exist)
279                                 goto fail_unlock;
280                         else
281                                 goto found;
282                 }
283 scan_primary_hash:
284                 if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
285                                         saddr_comp, 0))
286                         goto fail_unlock;
287         }
288 found:
289         inet_sk(sk)->inet_num = snum;
290         udp_sk(sk)->udp_port_hash = snum;
291         udp_sk(sk)->udp_portaddr_hash ^= snum;
292         if (sk_unhashed(sk)) {
293                 sk_nulls_add_node_rcu(sk, &hslot->head);
294                 hslot->count++;
295                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
296 
297                 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
298                 spin_lock(&hslot2->lock);
299                 hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
300                                          &hslot2->head);
301                 hslot2->count++;
302                 spin_unlock(&hslot2->lock);
303         }
304         error = 0;
305 fail_unlock:
306         spin_unlock_bh(&hslot->lock);
307 fail:
308         return error;
309 }
310 EXPORT_SYMBOL(udp_lib_get_port);
311 
312 static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
313 {
314         struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
315 
316         return  (!ipv6_only_sock(sk2)  &&
317                  (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
318                    inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
319 }
320 
321 static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
322                                        unsigned int port)
323 {
324         return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
325 }
326 
327 int udp_v4_get_port(struct sock *sk, unsigned short snum)
328 {
329         unsigned int hash2_nulladdr =
330                 udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
331         unsigned int hash2_partial =
332                 udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
333 
334         /* precompute partial secondary hash */
335         udp_sk(sk)->udp_portaddr_hash = hash2_partial;
336         return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
337 }
338 
339 static inline int compute_score(struct sock *sk, struct net *net,
340                                 __be32 saddr, unsigned short hnum, __be16 sport,
341                                 __be32 daddr, __be16 dport, int dif)
342 {
343         int score;
344         struct inet_sock *inet;
345 
346         if (!net_eq(sock_net(sk), net) ||
347             udp_sk(sk)->udp_port_hash != hnum ||
348             ipv6_only_sock(sk))
349                 return -1;
350 
351         score = (sk->sk_family == PF_INET) ? 2 : 1;
352         inet = inet_sk(sk);
353 
354         if (inet->inet_rcv_saddr) {
355                 if (inet->inet_rcv_saddr != daddr)
356                         return -1;
357                 score += 4;
358         }
359 
360         if (inet->inet_daddr) {
361                 if (inet->inet_daddr != saddr)
362                         return -1;
363                 score += 4;
364         }
365 
366         if (inet->inet_dport) {
367                 if (inet->inet_dport != sport)
368                         return -1;
369                 score += 4;
370         }
371 
372         if (sk->sk_bound_dev_if) {
373                 if (sk->sk_bound_dev_if != dif)
374                         return -1;
375                 score += 4;
376         }
377 
378         return score;
379 }
380 
381 /*
382  * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
383  */
384 static inline int compute_score2(struct sock *sk, struct net *net,
385                                  __be32 saddr, __be16 sport,
386                                  __be32 daddr, unsigned int hnum, int dif)
387 {
388         int score;
389         struct inet_sock *inet;
390 
391         if (!net_eq(sock_net(sk), net) ||
392             ipv6_only_sock(sk))
393                 return -1;
394 
395         inet = inet_sk(sk);
396 
397         if (inet->inet_rcv_saddr != daddr ||
398             inet->inet_num != hnum)
399                 return -1;
400 
401         score = (sk->sk_family == PF_INET) ? 2 : 1;
402 
403         if (inet->inet_daddr) {
404                 if (inet->inet_daddr != saddr)
405                         return -1;
406                 score += 4;
407         }
408 
409         if (inet->inet_dport) {
410                 if (inet->inet_dport != sport)
411                         return -1;
412                 score += 4;
413         }
414 
415         if (sk->sk_bound_dev_if) {
416                 if (sk->sk_bound_dev_if != dif)
417                         return -1;
418                 score += 4;
419         }
420 
421         return score;
422 }
423 
424 static unsigned int udp_ehashfn(struct net *net, const __be32 laddr,
425                                  const __u16 lport, const __be32 faddr,
426                                  const __be16 fport)
427 {
428         static u32 udp_ehash_secret __read_mostly;
429 
430         net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
431 
432         return __inet_ehashfn(laddr, lport, faddr, fport,
433                               udp_ehash_secret + net_hash_mix(net));
434 }
435 
436 
437 /* called with read_rcu_lock() */
438 static struct sock *udp4_lib_lookup2(struct net *net,
439                 __be32 saddr, __be16 sport,
440                 __be32 daddr, unsigned int hnum, int dif,
441                 struct udp_hslot *hslot2, unsigned int slot2)
442 {
443         struct sock *sk, *result;
444         struct hlist_nulls_node *node;
445         int score, badness, matches = 0, reuseport = 0;
446         u32 hash = 0;
447 
448 begin:
449         result = NULL;
450         badness = 0;
451         udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
452                 score = compute_score2(sk, net, saddr, sport,
453                                       daddr, hnum, dif);
454                 if (score > badness) {
455                         result = sk;
456                         badness = score;
457                         reuseport = sk->sk_reuseport;
458                         if (reuseport) {
459                                 hash = udp_ehashfn(net, daddr, hnum,
460                                                    saddr, sport);
461                                 matches = 1;
462                         }
463                 } else if (score == badness && reuseport) {
464                         matches++;
465                         if (reciprocal_scale(hash, matches) == 0)
466                                 result = sk;
467                         hash = next_pseudo_random32(hash);
468                 }
469         }
470         /*
471          * if the nulls value we got at the end of this lookup is
472          * not the expected one, we must restart lookup.
473          * We probably met an item that was moved to another chain.
474          */
475         if (get_nulls_value(node) != slot2)
476                 goto begin;
477         if (result) {
478                 if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
479                         result = NULL;
480                 else if (unlikely(compute_score2(result, net, saddr, sport,
481                                   daddr, hnum, dif) < badness)) {
482                         sock_put(result);
483                         goto begin;
484                 }
485         }
486         return result;
487 }
488 
489 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
490  * harder than this. -DaveM
491  */
492 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
493                 __be16 sport, __be32 daddr, __be16 dport,
494                 int dif, struct udp_table *udptable)
495 {
496         struct sock *sk, *result;
497         struct hlist_nulls_node *node;
498         unsigned short hnum = ntohs(dport);
499         unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
500         struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
501         int score, badness, matches = 0, reuseport = 0;
502         u32 hash = 0;
503 
504         rcu_read_lock();
505         if (hslot->count > 10) {
506                 hash2 = udp4_portaddr_hash(net, daddr, hnum);
507                 slot2 = hash2 & udptable->mask;
508                 hslot2 = &udptable->hash2[slot2];
509                 if (hslot->count < hslot2->count)
510                         goto begin;
511 
512                 result = udp4_lib_lookup2(net, saddr, sport,
513                                           daddr, hnum, dif,
514                                           hslot2, slot2);
515                 if (!result) {
516                         hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
517                         slot2 = hash2 & udptable->mask;
518                         hslot2 = &udptable->hash2[slot2];
519                         if (hslot->count < hslot2->count)
520                                 goto begin;
521 
522                         result = udp4_lib_lookup2(net, saddr, sport,
523                                                   htonl(INADDR_ANY), hnum, dif,
524                                                   hslot2, slot2);
525                 }
526                 rcu_read_unlock();
527                 return result;
528         }
529 begin:
530         result = NULL;
531         badness = 0;
532         sk_nulls_for_each_rcu(sk, node, &hslot->head) {
533                 score = compute_score(sk, net, saddr, hnum, sport,
534                                       daddr, dport, dif);
535                 if (score > badness) {
536                         result = sk;
537                         badness = score;
538                         reuseport = sk->sk_reuseport;
539                         if (reuseport) {
540                                 hash = udp_ehashfn(net, daddr, hnum,
541                                                    saddr, sport);
542                                 matches = 1;
543                         }
544                 } else if (score == badness && reuseport) {
545                         matches++;
546                         if (reciprocal_scale(hash, matches) == 0)
547                                 result = sk;
548                         hash = next_pseudo_random32(hash);
549                 }
550         }
551         /*
552          * if the nulls value we got at the end of this lookup is
553          * not the expected one, we must restart lookup.
554          * We probably met an item that was moved to another chain.
555          */
556         if (get_nulls_value(node) != slot)
557                 goto begin;
558 
559         if (result) {
560                 if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
561                         result = NULL;
562                 else if (unlikely(compute_score(result, net, saddr, hnum, sport,
563                                   daddr, dport, dif) < badness)) {
564                         sock_put(result);
565                         goto begin;
566                 }
567         }
568         rcu_read_unlock();
569         return result;
570 }
571 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
572 
573 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
574                                                  __be16 sport, __be16 dport,
575                                                  struct udp_table *udptable)
576 {
577         const struct iphdr *iph = ip_hdr(skb);
578 
579         return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
580                                  iph->daddr, dport, inet_iif(skb),
581                                  udptable);
582 }
583 
584 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
585                              __be32 daddr, __be16 dport, int dif)
586 {
587         return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
588 }
589 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
590 
591 static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
592                                        __be16 loc_port, __be32 loc_addr,
593                                        __be16 rmt_port, __be32 rmt_addr,
594                                        int dif, unsigned short hnum)
595 {
596         struct inet_sock *inet = inet_sk(sk);
597 
598         if (!net_eq(sock_net(sk), net) ||
599             udp_sk(sk)->udp_port_hash != hnum ||
600             (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
601             (inet->inet_dport != rmt_port && inet->inet_dport) ||
602             (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
603             ipv6_only_sock(sk) ||
604             (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
605                 return false;
606         if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif))
607                 return false;
608         return true;
609 }
610 
611 /*
612  * This routine is called by the ICMP module when it gets some
613  * sort of error condition.  If err < 0 then the socket should
614  * be closed and the error returned to the user.  If err > 0
615  * it's just the icmp type << 8 | icmp code.
616  * Header points to the ip header of the error packet. We move
617  * on past this. Then (as it used to claim before adjustment)
618  * header points to the first 8 bytes of the udp header.  We need
619  * to find the appropriate port.
620  */
621 
622 void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
623 {
624         struct inet_sock *inet;
625         const struct iphdr *iph = (const struct iphdr *)skb->data;
626         struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
627         const int type = icmp_hdr(skb)->type;
628         const int code = icmp_hdr(skb)->code;
629         struct sock *sk;
630         int harderr;
631         int err;
632         struct net *net = dev_net(skb->dev);
633 
634         sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
635                         iph->saddr, uh->source, skb->dev->ifindex, udptable);
636         if (sk == NULL) {
637                 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
638                 return; /* No socket for error */
639         }
640 
641         err = 0;
642         harderr = 0;
643         inet = inet_sk(sk);
644 
645         switch (type) {
646         default:
647         case ICMP_TIME_EXCEEDED:
648                 err = EHOSTUNREACH;
649                 break;
650         case ICMP_SOURCE_QUENCH:
651                 goto out;
652         case ICMP_PARAMETERPROB:
653                 err = EPROTO;
654                 harderr = 1;
655                 break;
656         case ICMP_DEST_UNREACH:
657                 if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
658                         ipv4_sk_update_pmtu(skb, sk, info);
659                         if (inet->pmtudisc != IP_PMTUDISC_DONT) {
660                                 err = EMSGSIZE;
661                                 harderr = 1;
662                                 break;
663                         }
664                         goto out;
665                 }
666                 err = EHOSTUNREACH;
667                 if (code <= NR_ICMP_UNREACH) {
668                         harderr = icmp_err_convert[code].fatal;
669                         err = icmp_err_convert[code].errno;
670                 }
671                 break;
672         case ICMP_REDIRECT:
673                 ipv4_sk_redirect(skb, sk);
674                 goto out;
675         }
676 
677         /*
678          *      RFC1122: OK.  Passes ICMP errors back to application, as per
679          *      4.1.3.3.
680          */
681         if (!inet->recverr) {
682                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
683                         goto out;
684         } else
685                 ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
686 
687         sk->sk_err = err;
688         sk->sk_error_report(sk);
689 out:
690         sock_put(sk);
691 }
692 
693 void udp_err(struct sk_buff *skb, u32 info)
694 {
695         __udp4_lib_err(skb, info, &udp_table);
696 }
697 
698 /*
699  * Throw away all pending data and cancel the corking. Socket is locked.
700  */
701 void udp_flush_pending_frames(struct sock *sk)
702 {
703         struct udp_sock *up = udp_sk(sk);
704 
705         if (up->pending) {
706                 up->len = 0;
707                 up->pending = 0;
708                 ip_flush_pending_frames(sk);
709         }
710 }
711 EXPORT_SYMBOL(udp_flush_pending_frames);
712 
713 /**
714  *      udp4_hwcsum  -  handle outgoing HW checksumming
715  *      @skb:   sk_buff containing the filled-in UDP header
716  *              (checksum field must be zeroed out)
717  *      @src:   source IP address
718  *      @dst:   destination IP address
719  */
720 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
721 {
722         struct udphdr *uh = udp_hdr(skb);
723         int offset = skb_transport_offset(skb);
724         int len = skb->len - offset;
725         int hlen = len;
726         __wsum csum = 0;
727 
728         if (!skb_has_frag_list(skb)) {
729                 /*
730                  * Only one fragment on the socket.
731                  */
732                 skb->csum_start = skb_transport_header(skb) - skb->head;
733                 skb->csum_offset = offsetof(struct udphdr, check);
734                 uh->check = ~csum_tcpudp_magic(src, dst, len,
735                                                IPPROTO_UDP, 0);
736         } else {
737                 struct sk_buff *frags;
738 
739                 /*
740                  * HW-checksum won't work as there are two or more
741                  * fragments on the socket so that all csums of sk_buffs
742                  * should be together
743                  */
744                 skb_walk_frags(skb, frags) {
745                         csum = csum_add(csum, frags->csum);
746                         hlen -= frags->len;
747                 }
748 
749                 csum = skb_checksum(skb, offset, hlen, csum);
750                 skb->ip_summed = CHECKSUM_NONE;
751 
752                 uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
753                 if (uh->check == 0)
754                         uh->check = CSUM_MANGLED_0;
755         }
756 }
757 EXPORT_SYMBOL_GPL(udp4_hwcsum);
758 
759 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended
760  * for the simple case like when setting the checksum for a UDP tunnel.
761  */
762 void udp_set_csum(bool nocheck, struct sk_buff *skb,
763                   __be32 saddr, __be32 daddr, int len)
764 {
765         struct udphdr *uh = udp_hdr(skb);
766 
767         if (nocheck)
768                 uh->check = 0;
769         else if (skb_is_gso(skb))
770                 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
771         else if (skb_dst(skb) && skb_dst(skb)->dev &&
772                  (skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
773 
774                 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
775 
776                 skb->ip_summed = CHECKSUM_PARTIAL;
777                 skb->csum_start = skb_transport_header(skb) - skb->head;
778                 skb->csum_offset = offsetof(struct udphdr, check);
779                 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
780         } else {
781                 __wsum csum;
782 
783                 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
784 
785                 uh->check = 0;
786                 csum = skb_checksum(skb, 0, len, 0);
787                 uh->check = udp_v4_check(len, saddr, daddr, csum);
788                 if (uh->check == 0)
789                         uh->check = CSUM_MANGLED_0;
790 
791                 skb->ip_summed = CHECKSUM_UNNECESSARY;
792         }
793 }
794 EXPORT_SYMBOL(udp_set_csum);
795 
796 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
797 {
798         struct sock *sk = skb->sk;
799         struct inet_sock *inet = inet_sk(sk);
800         struct udphdr *uh;
801         int err = 0;
802         int is_udplite = IS_UDPLITE(sk);
803         int offset = skb_transport_offset(skb);
804         int len = skb->len - offset;
805         __wsum csum = 0;
806 
807         /*
808          * Create a UDP header
809          */
810         uh = udp_hdr(skb);
811         uh->source = inet->inet_sport;
812         uh->dest = fl4->fl4_dport;
813         uh->len = htons(len);
814         uh->check = 0;
815 
816         if (is_udplite)                                  /*     UDP-Lite      */
817                 csum = udplite_csum(skb);
818 
819         else if (sk->sk_no_check_tx) {   /* UDP csum disabled */
820 
821                 skb->ip_summed = CHECKSUM_NONE;
822                 goto send;
823 
824         } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
825 
826                 udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
827                 goto send;
828 
829         } else
830                 csum = udp_csum(skb);
831 
832         /* add protocol-dependent pseudo-header */
833         uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
834                                       sk->sk_protocol, csum);
835         if (uh->check == 0)
836                 uh->check = CSUM_MANGLED_0;
837 
838 send:
839         err = ip_send_skb(sock_net(sk), skb);
840         if (err) {
841                 if (err == -ENOBUFS && !inet->recverr) {
842                         UDP_INC_STATS_USER(sock_net(sk),
843                                            UDP_MIB_SNDBUFERRORS, is_udplite);
844                         err = 0;
845                 }
846         } else
847                 UDP_INC_STATS_USER(sock_net(sk),
848                                    UDP_MIB_OUTDATAGRAMS, is_udplite);
849         return err;
850 }
851 
852 /*
853  * Push out all pending data as one UDP datagram. Socket is locked.
854  */
855 int udp_push_pending_frames(struct sock *sk)
856 {
857         struct udp_sock  *up = udp_sk(sk);
858         struct inet_sock *inet = inet_sk(sk);
859         struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
860         struct sk_buff *skb;
861         int err = 0;
862 
863         skb = ip_finish_skb(sk, fl4);
864         if (!skb)
865                 goto out;
866 
867         err = udp_send_skb(skb, fl4);
868 
869 out:
870         up->len = 0;
871         up->pending = 0;
872         return err;
873 }
874 EXPORT_SYMBOL(udp_push_pending_frames);
875 
876 int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
877                 size_t len)
878 {
879         struct inet_sock *inet = inet_sk(sk);
880         struct udp_sock *up = udp_sk(sk);
881         struct flowi4 fl4_stack;
882         struct flowi4 *fl4;
883         int ulen = len;
884         struct ipcm_cookie ipc;
885         struct rtable *rt = NULL;
886         int free = 0;
887         int connected = 0;
888         __be32 daddr, faddr, saddr;
889         __be16 dport;
890         u8  tos;
891         int err, is_udplite = IS_UDPLITE(sk);
892         int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
893         int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
894         struct sk_buff *skb;
895         struct ip_options_data opt_copy;
896 
897         if (len > 0xFFFF)
898                 return -EMSGSIZE;
899 
900         /*
901          *      Check the flags.
902          */
903 
904         if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
905                 return -EOPNOTSUPP;
906 
907         ipc.opt = NULL;
908         ipc.tx_flags = 0;
909         ipc.ttl = 0;
910         ipc.tos = -1;
911 
912         getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
913 
914         fl4 = &inet->cork.fl.u.ip4;
915         if (up->pending) {
916                 /*
917                  * There are pending frames.
918                  * The socket lock must be held while it's corked.
919                  */
920                 lock_sock(sk);
921                 if (likely(up->pending)) {
922                         if (unlikely(up->pending != AF_INET)) {
923                                 release_sock(sk);
924                                 return -EINVAL;
925                         }
926                         goto do_append_data;
927                 }
928                 release_sock(sk);
929         }
930         ulen += sizeof(struct udphdr);
931 
932         /*
933          *      Get and verify the address.
934          */
935         if (msg->msg_name) {
936                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
937                 if (msg->msg_namelen < sizeof(*usin))
938                         return -EINVAL;
939                 if (usin->sin_family != AF_INET) {
940                         if (usin->sin_family != AF_UNSPEC)
941                                 return -EAFNOSUPPORT;
942                 }
943 
944                 daddr = usin->sin_addr.s_addr;
945                 dport = usin->sin_port;
946                 if (dport == 0)
947                         return -EINVAL;
948         } else {
949                 if (sk->sk_state != TCP_ESTABLISHED)
950                         return -EDESTADDRREQ;
951                 daddr = inet->inet_daddr;
952                 dport = inet->inet_dport;
953                 /* Open fast path for connected socket.
954                    Route will not be used, if at least one option is set.
955                  */
956                 connected = 1;
957         }
958         ipc.addr = inet->inet_saddr;
959 
960         ipc.oif = sk->sk_bound_dev_if;
961 
962         sock_tx_timestamp(sk, &ipc.tx_flags);
963 
964         if (msg->msg_controllen) {
965                 err = ip_cmsg_send(sock_net(sk), msg, &ipc,
966                                    sk->sk_family == AF_INET6);
967                 if (err)
968                         return err;
969                 if (ipc.opt)
970                         free = 1;
971                 connected = 0;
972         }
973         if (!ipc.opt) {
974                 struct ip_options_rcu *inet_opt;
975 
976                 rcu_read_lock();
977                 inet_opt = rcu_dereference(inet->inet_opt);
978                 if (inet_opt) {
979                         memcpy(&opt_copy, inet_opt,
980                                sizeof(*inet_opt) + inet_opt->opt.optlen);
981                         ipc.opt = &opt_copy.opt;
982                 }
983                 rcu_read_unlock();
984         }
985 
986         saddr = ipc.addr;
987         ipc.addr = faddr = daddr;
988 
989         if (ipc.opt && ipc.opt->opt.srr) {
990                 if (!daddr)
991                         return -EINVAL;
992                 faddr = ipc.opt->opt.faddr;
993                 connected = 0;
994         }
995         tos = get_rttos(&ipc, inet);
996         if (sock_flag(sk, SOCK_LOCALROUTE) ||
997             (msg->msg_flags & MSG_DONTROUTE) ||
998             (ipc.opt && ipc.opt->opt.is_strictroute)) {
999                 tos |= RTO_ONLINK;
1000                 connected = 0;
1001         }
1002 
1003         if (ipv4_is_multicast(daddr)) {
1004                 if (!ipc.oif)
1005                         ipc.oif = inet->mc_index;
1006                 if (!saddr)
1007                         saddr = inet->mc_addr;
1008                 connected = 0;
1009         } else if (!ipc.oif)
1010                 ipc.oif = inet->uc_index;
1011 
1012         if (connected)
1013                 rt = (struct rtable *)sk_dst_check(sk, 0);
1014 
1015         if (rt == NULL) {
1016                 struct net *net = sock_net(sk);
1017 
1018                 fl4 = &fl4_stack;
1019                 flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
1020                                    RT_SCOPE_UNIVERSE, sk->sk_protocol,
1021                                    inet_sk_flowi_flags(sk),
1022                                    faddr, saddr, dport, inet->inet_sport);
1023 
1024                 security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
1025                 rt = ip_route_output_flow(net, fl4, sk);
1026                 if (IS_ERR(rt)) {
1027                         err = PTR_ERR(rt);
1028                         rt = NULL;
1029                         if (err == -ENETUNREACH)
1030                                 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1031                         goto out;
1032                 }
1033 
1034                 err = -EACCES;
1035                 if ((rt->rt_flags & RTCF_BROADCAST) &&
1036                     !sock_flag(sk, SOCK_BROADCAST))
1037                         goto out;
1038                 if (connected)
1039                         sk_dst_set(sk, dst_clone(&rt->dst));
1040         }
1041 
1042         if (msg->msg_flags&MSG_CONFIRM)
1043                 goto do_confirm;
1044 back_from_confirm:
1045 
1046         saddr = fl4->saddr;
1047         if (!ipc.addr)
1048                 daddr = ipc.addr = fl4->daddr;
1049 
1050         /* Lockless fast path for the non-corking case. */
1051         if (!corkreq) {
1052                 skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
1053                                   sizeof(struct udphdr), &ipc, &rt,
1054                                   msg->msg_flags);
1055                 err = PTR_ERR(skb);
1056                 if (!IS_ERR_OR_NULL(skb))
1057                         err = udp_send_skb(skb, fl4);
1058                 goto out;
1059         }
1060 
1061         lock_sock(sk);
1062         if (unlikely(up->pending)) {
1063                 /* The socket is already corked while preparing it. */
1064                 /* ... which is an evident application bug. --ANK */
1065                 release_sock(sk);
1066 
1067                 net_dbg_ratelimited("cork app bug 2\n");
1068                 err = -EINVAL;
1069                 goto out;
1070         }
1071         /*
1072          *      Now cork the socket to pend data.
1073          */
1074         fl4 = &inet->cork.fl.u.ip4;
1075         fl4->daddr = daddr;
1076         fl4->saddr = saddr;
1077         fl4->fl4_dport = dport;
1078         fl4->fl4_sport = inet->inet_sport;
1079         up->pending = AF_INET;
1080 
1081 do_append_data:
1082         up->len += ulen;
1083         err = ip_append_data(sk, fl4, getfrag, msg, ulen,
1084                              sizeof(struct udphdr), &ipc, &rt,
1085                              corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1086         if (err)
1087                 udp_flush_pending_frames(sk);
1088         else if (!corkreq)
1089                 err = udp_push_pending_frames(sk);
1090         else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1091                 up->pending = 0;
1092         release_sock(sk);
1093 
1094 out:
1095         ip_rt_put(rt);
1096         if (free)
1097                 kfree(ipc.opt);
1098         if (!err)
1099                 return len;
1100         /*
1101          * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1102          * ENOBUFS might not be good (it's not tunable per se), but otherwise
1103          * we don't have a good statistic (IpOutDiscards but it can be too many
1104          * things).  We could add another new stat but at least for now that
1105          * seems like overkill.
1106          */
1107         if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1108                 UDP_INC_STATS_USER(sock_net(sk),
1109                                 UDP_MIB_SNDBUFERRORS, is_udplite);
1110         }
1111         return err;
1112 
1113 do_confirm:
1114         dst_confirm(&rt->dst);
1115         if (!(msg->msg_flags&MSG_PROBE) || len)
1116                 goto back_from_confirm;
1117         err = 0;
1118         goto out;
1119 }
1120 EXPORT_SYMBOL(udp_sendmsg);
1121 
1122 int udp_sendpage(struct sock *sk, struct page *page, int offset,
1123                  size_t size, int flags)
1124 {
1125         struct inet_sock *inet = inet_sk(sk);
1126         struct udp_sock *up = udp_sk(sk);
1127         int ret;
1128 
1129         if (flags & MSG_SENDPAGE_NOTLAST)
1130                 flags |= MSG_MORE;
1131 
1132         if (!up->pending) {
1133                 struct msghdr msg = {   .msg_flags = flags|MSG_MORE };
1134 
1135                 /* Call udp_sendmsg to specify destination address which
1136                  * sendpage interface can't pass.
1137                  * This will succeed only when the socket is connected.
1138                  */
1139                 ret = udp_sendmsg(NULL, sk, &msg, 0);
1140                 if (ret < 0)
1141                         return ret;
1142         }
1143 
1144         lock_sock(sk);
1145 
1146         if (unlikely(!up->pending)) {
1147                 release_sock(sk);
1148 
1149                 net_dbg_ratelimited("udp cork app bug 3\n");
1150                 return -EINVAL;
1151         }
1152 
1153         ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1154                              page, offset, size, flags);
1155         if (ret == -EOPNOTSUPP) {
1156                 release_sock(sk);
1157                 return sock_no_sendpage(sk->sk_socket, page, offset,
1158                                         size, flags);
1159         }
1160         if (ret < 0) {
1161                 udp_flush_pending_frames(sk);
1162                 goto out;
1163         }
1164 
1165         up->len += size;
1166         if (!(up->corkflag || (flags&MSG_MORE)))
1167                 ret = udp_push_pending_frames(sk);
1168         if (!ret)
1169                 ret = size;
1170 out:
1171         release_sock(sk);
1172         return ret;
1173 }
1174 
1175 
1176 /**
1177  *      first_packet_length     - return length of first packet in receive queue
1178  *      @sk: socket
1179  *
1180  *      Drops all bad checksum frames, until a valid one is found.
1181  *      Returns the length of found skb, or 0 if none is found.
1182  */
1183 static unsigned int first_packet_length(struct sock *sk)
1184 {
1185         struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
1186         struct sk_buff *skb;
1187         unsigned int res;
1188 
1189         __skb_queue_head_init(&list_kill);
1190 
1191         spin_lock_bh(&rcvq->lock);
1192         while ((skb = skb_peek(rcvq)) != NULL &&
1193                 udp_lib_checksum_complete(skb)) {
1194                 UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS,
1195                                  IS_UDPLITE(sk));
1196                 UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1197                                  IS_UDPLITE(sk));
1198                 atomic_inc(&sk->sk_drops);
1199                 __skb_unlink(skb, rcvq);
1200                 __skb_queue_tail(&list_kill, skb);
1201         }
1202         res = skb ? skb->len : 0;
1203         spin_unlock_bh(&rcvq->lock);
1204 
1205         if (!skb_queue_empty(&list_kill)) {
1206                 bool slow = lock_sock_fast(sk);
1207 
1208                 __skb_queue_purge(&list_kill);
1209                 sk_mem_reclaim_partial(sk);
1210                 unlock_sock_fast(sk, slow);
1211         }
1212         return res;
1213 }
1214 
1215 /*
1216  *      IOCTL requests applicable to the UDP protocol
1217  */
1218 
1219 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1220 {
1221         switch (cmd) {
1222         case SIOCOUTQ:
1223         {
1224                 int amount = sk_wmem_alloc_get(sk);
1225 
1226                 return put_user(amount, (int __user *)arg);
1227         }
1228 
1229         case SIOCINQ:
1230         {
1231                 unsigned int amount = first_packet_length(sk);
1232 
1233                 if (amount)
1234                         /*
1235                          * We will only return the amount
1236                          * of this packet since that is all
1237                          * that will be read.
1238                          */
1239                         amount -= sizeof(struct udphdr);
1240 
1241                 return put_user(amount, (int __user *)arg);
1242         }
1243 
1244         default:
1245                 return -ENOIOCTLCMD;
1246         }
1247 
1248         return 0;
1249 }
1250 EXPORT_SYMBOL(udp_ioctl);
1251 
1252 /*
1253  *      This should be easy, if there is something there we
1254  *      return it, otherwise we block.
1255  */
1256 
1257 int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1258                 size_t len, int noblock, int flags, int *addr_len)
1259 {
1260         struct inet_sock *inet = inet_sk(sk);
1261         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1262         struct sk_buff *skb;
1263         unsigned int ulen, copied;
1264         int peeked, off = 0;
1265         int err;
1266         int is_udplite = IS_UDPLITE(sk);
1267         bool slow;
1268 
1269         if (flags & MSG_ERRQUEUE)
1270                 return ip_recv_error(sk, msg, len, addr_len);
1271 
1272 try_again:
1273         skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1274                                   &peeked, &off, &err);
1275         if (!skb)
1276                 goto out;
1277 
1278         ulen = skb->len - sizeof(struct udphdr);
1279         copied = len;
1280         if (copied > ulen)
1281                 copied = ulen;
1282         else if (copied < ulen)
1283                 msg->msg_flags |= MSG_TRUNC;
1284 
1285         /*
1286          * If checksum is needed at all, try to do it while copying the
1287          * data.  If the data is truncated, or if we only want a partial
1288          * coverage checksum (UDP-Lite), do it before the copy.
1289          */
1290 
1291         if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1292                 if (udp_lib_checksum_complete(skb))
1293                         goto csum_copy_err;
1294         }
1295 
1296         if (skb_csum_unnecessary(skb))
1297                 err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
1298                                             msg, copied);
1299         else {
1300                 err = skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr),
1301                                                      msg);
1302 
1303                 if (err == -EINVAL)
1304                         goto csum_copy_err;
1305         }
1306 
1307         if (unlikely(err)) {
1308                 trace_kfree_skb(skb, udp_recvmsg);
1309                 if (!peeked) {
1310                         atomic_inc(&sk->sk_drops);
1311                         UDP_INC_STATS_USER(sock_net(sk),
1312                                            UDP_MIB_INERRORS, is_udplite);
1313                 }
1314                 goto out_free;
1315         }
1316 
1317         if (!peeked)
1318                 UDP_INC_STATS_USER(sock_net(sk),
1319                                 UDP_MIB_INDATAGRAMS, is_udplite);
1320 
1321         sock_recv_ts_and_drops(msg, sk, skb);
1322 
1323         /* Copy the address. */
1324         if (sin) {
1325                 sin->sin_family = AF_INET;
1326                 sin->sin_port = udp_hdr(skb)->source;
1327                 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1328                 memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1329                 *addr_len = sizeof(*sin);
1330         }
1331         if (inet->cmsg_flags)
1332                 ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));
1333 
1334         err = copied;
1335         if (flags & MSG_TRUNC)
1336                 err = ulen;
1337 
1338 out_free:
1339         skb_free_datagram_locked(sk, skb);
1340 out:
1341         return err;
1342 
1343 csum_copy_err:
1344         slow = lock_sock_fast(sk);
1345         if (!skb_kill_datagram(sk, skb, flags)) {
1346                 UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1347                 UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1348         }
1349         unlock_sock_fast(sk, slow);
1350 
1351         if (noblock)
1352                 return -EAGAIN;
1353 
1354         /* starting over for a new packet */
1355         msg->msg_flags &= ~MSG_TRUNC;
1356         goto try_again;
1357 }
1358 
1359 
1360 int udp_disconnect(struct sock *sk, int flags)
1361 {
1362         struct inet_sock *inet = inet_sk(sk);
1363         /*
1364          *      1003.1g - break association.
1365          */
1366 
1367         sk->sk_state = TCP_CLOSE;
1368         inet->inet_daddr = 0;
1369         inet->inet_dport = 0;
1370         sock_rps_reset_rxhash(sk);
1371         sk->sk_bound_dev_if = 0;
1372         if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1373                 inet_reset_saddr(sk);
1374 
1375         if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1376                 sk->sk_prot->unhash(sk);
1377                 inet->inet_sport = 0;
1378         }
1379         sk_dst_reset(sk);
1380         return 0;
1381 }
1382 EXPORT_SYMBOL(udp_disconnect);
1383 
1384 void udp_lib_unhash(struct sock *sk)
1385 {
1386         if (sk_hashed(sk)) {
1387                 struct udp_table *udptable = sk->sk_prot->h.udp_table;
1388                 struct udp_hslot *hslot, *hslot2;
1389 
1390                 hslot  = udp_hashslot(udptable, sock_net(sk),
1391                                       udp_sk(sk)->udp_port_hash);
1392                 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1393 
1394                 spin_lock_bh(&hslot->lock);
1395                 if (sk_nulls_del_node_init_rcu(sk)) {
1396                         hslot->count--;
1397                         inet_sk(sk)->inet_num = 0;
1398                         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1399 
1400                         spin_lock(&hslot2->lock);
1401                         hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1402                         hslot2->count--;
1403                         spin_unlock(&hslot2->lock);
1404                 }
1405                 spin_unlock_bh(&hslot->lock);
1406         }
1407 }
1408 EXPORT_SYMBOL(udp_lib_unhash);
1409 
1410 /*
1411  * inet_rcv_saddr was changed, we must rehash secondary hash
1412  */
1413 void udp_lib_rehash(struct sock *sk, u16 newhash)
1414 {
1415         if (sk_hashed(sk)) {
1416                 struct udp_table *udptable = sk->sk_prot->h.udp_table;
1417                 struct udp_hslot *hslot, *hslot2, *nhslot2;
1418 
1419                 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1420                 nhslot2 = udp_hashslot2(udptable, newhash);
1421                 udp_sk(sk)->udp_portaddr_hash = newhash;
1422                 if (hslot2 != nhslot2) {
1423                         hslot = udp_hashslot(udptable, sock_net(sk),
1424                                              udp_sk(sk)->udp_port_hash);
1425                         /* we must lock primary chain too */
1426                         spin_lock_bh(&hslot->lock);
1427 
1428                         spin_lock(&hslot2->lock);
1429                         hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1430                         hslot2->count--;
1431                         spin_unlock(&hslot2->lock);
1432 
1433                         spin_lock(&nhslot2->lock);
1434                         hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1435                                                  &nhslot2->head);
1436                         nhslot2->count++;
1437                         spin_unlock(&nhslot2->lock);
1438 
1439                         spin_unlock_bh(&hslot->lock);
1440                 }
1441         }
1442 }
1443 EXPORT_SYMBOL(udp_lib_rehash);
1444 
1445 static void udp_v4_rehash(struct sock *sk)
1446 {
1447         u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1448                                           inet_sk(sk)->inet_rcv_saddr,
1449                                           inet_sk(sk)->inet_num);
1450         udp_lib_rehash(sk, new_hash);
1451 }
1452 
1453 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1454 {
1455         int rc;
1456 
1457         if (inet_sk(sk)->inet_daddr) {
1458                 sock_rps_save_rxhash(sk, skb);
1459                 sk_mark_napi_id(sk, skb);
1460                 sk_incoming_cpu_update(sk);
1461         }
1462 
1463         rc = sock_queue_rcv_skb(sk, skb);
1464         if (rc < 0) {
1465                 int is_udplite = IS_UDPLITE(sk);
1466 
1467                 /* Note that an ENOMEM error is charged twice */
1468                 if (rc == -ENOMEM)
1469                         UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1470                                          is_udplite);
1471                 UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1472                 kfree_skb(skb);
1473                 trace_udp_fail_queue_rcv_skb(rc, sk);
1474                 return -1;
1475         }
1476 
1477         return 0;
1478 
1479 }
1480 
1481 static struct static_key udp_encap_needed __read_mostly;
1482 void udp_encap_enable(void)
1483 {
1484         if (!static_key_enabled(&udp_encap_needed))
1485                 static_key_slow_inc(&udp_encap_needed);
1486 }
1487 EXPORT_SYMBOL(udp_encap_enable);
1488 
1489 /* returns:
1490  *  -1: error
1491  *   0: success
1492  *  >0: "udp encap" protocol resubmission
1493  *
1494  * Note that in the success and error cases, the skb is assumed to
1495  * have either been requeued or freed.
1496  */
1497 int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1498 {
1499         struct udp_sock *up = udp_sk(sk);
1500         int rc;
1501         int is_udplite = IS_UDPLITE(sk);
1502 
1503         /*
1504          *      Charge it to the socket, dropping if the queue is full.
1505          */
1506         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1507                 goto drop;
1508         nf_reset(skb);
1509 
1510         if (static_key_false(&udp_encap_needed) && up->encap_type) {
1511                 int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1512 
1513                 /*
1514                  * This is an encapsulation socket so pass the skb to
1515                  * the socket's udp_encap_rcv() hook. Otherwise, just
1516                  * fall through and pass this up the UDP socket.
1517                  * up->encap_rcv() returns the following value:
1518                  * =0 if skb was successfully passed to the encap
1519                  *    handler or was discarded by it.
1520                  * >0 if skb should be passed on to UDP.
1521                  * <0 if skb should be resubmitted as proto -N
1522                  */
1523 
1524                 /* if we're overly short, let UDP handle it */
1525                 encap_rcv = ACCESS_ONCE(up->encap_rcv);
1526                 if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1527                         int ret;
1528 
1529                         /* Verify checksum before giving to encap */
1530                         if (udp_lib_checksum_complete(skb))
1531                                 goto csum_error;
1532 
1533                         ret = encap_rcv(sk, skb);
1534                         if (ret <= 0) {
1535                                 UDP_INC_STATS_BH(sock_net(sk),
1536                                                  UDP_MIB_INDATAGRAMS,
1537                                                  is_udplite);
1538                                 return -ret;
1539                         }
1540                 }
1541 
1542                 /* FALLTHROUGH -- it's a UDP Packet */
1543         }
1544 
1545         /*
1546          *      UDP-Lite specific tests, ignored on UDP sockets
1547          */
1548         if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1549 
1550                 /*
1551                  * MIB statistics other than incrementing the error count are
1552                  * disabled for the following two types of errors: these depend
1553                  * on the application settings, not on the functioning of the
1554                  * protocol stack as such.
1555                  *
1556                  * RFC 3828 here recommends (sec 3.3): "There should also be a
1557                  * way ... to ... at least let the receiving application block
1558                  * delivery of packets with coverage values less than a value
1559                  * provided by the application."
1560                  */
1561                 if (up->pcrlen == 0) {          /* full coverage was set  */
1562                         net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
1563                                             UDP_SKB_CB(skb)->cscov, skb->len);
1564                         goto drop;
1565                 }
1566                 /* The next case involves violating the min. coverage requested
1567                  * by the receiver. This is subtle: if receiver wants x and x is
1568                  * greater than the buffersize/MTU then receiver will complain
1569                  * that it wants x while sender emits packets of smaller size y.
1570                  * Therefore the above ...()->partial_cov statement is essential.
1571                  */
1572                 if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1573                         net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
1574                                             UDP_SKB_CB(skb)->cscov, up->pcrlen);
1575                         goto drop;
1576                 }
1577         }
1578 
1579         if (rcu_access_pointer(sk->sk_filter) &&
1580             udp_lib_checksum_complete(skb))
1581                 goto csum_error;
1582 
1583 
1584         if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
1585                 UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1586                                  is_udplite);
1587                 goto drop;
1588         }
1589 
1590         rc = 0;
1591 
1592         ipv4_pktinfo_prepare(sk, skb);
1593         bh_lock_sock(sk);
1594         if (!sock_owned_by_user(sk))
1595                 rc = __udp_queue_rcv_skb(sk, skb);
1596         else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
1597                 bh_unlock_sock(sk);
1598                 goto drop;
1599         }
1600         bh_unlock_sock(sk);
1601 
1602         return rc;
1603 
1604 csum_error:
1605         UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1606 drop:
1607         UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1608         atomic_inc(&sk->sk_drops);
1609         kfree_skb(skb);
1610         return -1;
1611 }
1612 
1613 
1614 static void flush_stack(struct sock **stack, unsigned int count,
1615                         struct sk_buff *skb, unsigned int final)
1616 {
1617         unsigned int i;
1618         struct sk_buff *skb1 = NULL;
1619         struct sock *sk;
1620 
1621         for (i = 0; i < count; i++) {
1622                 sk = stack[i];
1623                 if (likely(skb1 == NULL))
1624                         skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1625 
1626                 if (!skb1) {
1627                         atomic_inc(&sk->sk_drops);
1628                         UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1629                                          IS_UDPLITE(sk));
1630                         UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1631                                          IS_UDPLITE(sk));
1632                 }
1633 
1634                 if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1635                         skb1 = NULL;
1636 
1637                 sock_put(sk);
1638         }
1639         if (unlikely(skb1))
1640                 kfree_skb(skb1);
1641 }
1642 
1643 /* For TCP sockets, sk_rx_dst is protected by socket lock
1644  * For UDP, we use xchg() to guard against concurrent changes.
1645  */
1646 static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
1647 {
1648         struct dst_entry *old;
1649 
1650         dst_hold(dst);
1651         old = xchg(&sk->sk_rx_dst, dst);
1652         dst_release(old);
1653 }
1654 
1655 /*
1656  *      Multicasts and broadcasts go to each listener.
1657  *
1658  *      Note: called only from the BH handler context.
1659  */
1660 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1661                                     struct udphdr  *uh,
1662                                     __be32 saddr, __be32 daddr,
1663                                     struct udp_table *udptable,
1664                                     int proto)
1665 {
1666         struct sock *sk, *stack[256 / sizeof(struct sock *)];
1667         struct hlist_nulls_node *node;
1668         unsigned short hnum = ntohs(uh->dest);
1669         struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
1670         int dif = skb->dev->ifindex;
1671         unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node);
1672         unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
1673         bool inner_flushed = false;
1674 
1675         if (use_hash2) {
1676                 hash2_any = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
1677                             udp_table.mask;
1678                 hash2 = udp4_portaddr_hash(net, daddr, hnum) & udp_table.mask;
1679 start_lookup:
1680                 hslot = &udp_table.hash2[hash2];
1681                 offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
1682         }
1683 
1684         spin_lock(&hslot->lock);
1685         sk_nulls_for_each_entry_offset(sk, node, &hslot->head, offset) {
1686                 if (__udp_is_mcast_sock(net, sk,
1687                                         uh->dest, daddr,
1688                                         uh->source, saddr,
1689                                         dif, hnum)) {
1690                         if (unlikely(count == ARRAY_SIZE(stack))) {
1691                                 flush_stack(stack, count, skb, ~0);
1692                                 inner_flushed = true;
1693                                 count = 0;
1694                         }
1695                         stack[count++] = sk;
1696                         sock_hold(sk);
1697                 }
1698         }
1699 
1700         spin_unlock(&hslot->lock);
1701 
1702         /* Also lookup *:port if we are using hash2 and haven't done so yet. */
1703         if (use_hash2 && hash2 != hash2_any) {
1704                 hash2 = hash2_any;
1705                 goto start_lookup;
1706         }
1707 
1708         /*
1709          * do the slow work with no lock held
1710          */
1711         if (count) {
1712                 flush_stack(stack, count, skb, count - 1);
1713         } else {
1714                 if (!inner_flushed)
1715                         UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI,
1716                                          proto == IPPROTO_UDPLITE);
1717                 consume_skb(skb);
1718         }
1719         return 0;
1720 }
1721 
1722 /* Initialize UDP checksum. If exited with zero value (success),
1723  * CHECKSUM_UNNECESSARY means, that no more checks are required.
1724  * Otherwise, csum completion requires chacksumming packet body,
1725  * including udp header and folding it to skb->csum.
1726  */
1727 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1728                                  int proto)
1729 {
1730         int err;
1731 
1732         UDP_SKB_CB(skb)->partial_cov = 0;
1733         UDP_SKB_CB(skb)->cscov = skb->len;
1734 
1735         if (proto == IPPROTO_UDPLITE) {
1736                 err = udplite_checksum_init(skb, uh);
1737                 if (err)
1738                         return err;
1739         }
1740 
1741         return skb_checksum_init_zero_check(skb, proto, uh->check,
1742                                             inet_compute_pseudo);
1743 }
1744 
1745 /*
1746  *      All we need to do is get the socket, and then do a checksum.
1747  */
1748 
1749 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1750                    int proto)
1751 {
1752         struct sock *sk;
1753         struct udphdr *uh;
1754         unsigned short ulen;
1755         struct rtable *rt = skb_rtable(skb);
1756         __be32 saddr, daddr;
1757         struct net *net = dev_net(skb->dev);
1758 
1759         /*
1760          *  Validate the packet.
1761          */
1762         if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1763                 goto drop;              /* No space for header. */
1764 
1765         uh   = udp_hdr(skb);
1766         ulen = ntohs(uh->len);
1767         saddr = ip_hdr(skb)->saddr;
1768         daddr = ip_hdr(skb)->daddr;
1769 
1770         if (ulen > skb->len)
1771                 goto short_packet;
1772 
1773         if (proto == IPPROTO_UDP) {
1774                 /* UDP validates ulen. */
1775                 if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1776                         goto short_packet;
1777                 uh = udp_hdr(skb);
1778         }
1779 
1780         if (udp4_csum_init(skb, uh, proto))
1781                 goto csum_error;
1782 
1783         sk = skb_steal_sock(skb);
1784         if (sk) {
1785                 struct dst_entry *dst = skb_dst(skb);
1786                 int ret;
1787 
1788                 if (unlikely(sk->sk_rx_dst != dst))
1789                         udp_sk_rx_dst_set(sk, dst);
1790 
1791                 ret = udp_queue_rcv_skb(sk, skb);
1792                 sock_put(sk);
1793                 /* a return value > 0 means to resubmit the input, but
1794                  * it wants the return to be -protocol, or 0
1795                  */
1796                 if (ret > 0)
1797                         return -ret;
1798                 return 0;
1799         }
1800 
1801         if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1802                 return __udp4_lib_mcast_deliver(net, skb, uh,
1803                                                 saddr, daddr, udptable, proto);
1804 
1805         sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1806         if (sk != NULL) {
1807                 int ret;
1808 
1809                 if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
1810                         skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
1811                                                  inet_compute_pseudo);
1812 
1813                 ret = udp_queue_rcv_skb(sk, skb);
1814                 sock_put(sk);
1815 
1816                 /* a return value > 0 means to resubmit the input, but
1817                  * it wants the return to be -protocol, or 0
1818                  */
1819                 if (ret > 0)
1820                         return -ret;
1821                 return 0;
1822         }
1823 
1824         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1825                 goto drop;
1826         nf_reset(skb);
1827 
1828         /* No socket. Drop packet silently, if checksum is wrong */
1829         if (udp_lib_checksum_complete(skb))
1830                 goto csum_error;
1831 
1832         UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1833         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1834 
1835         /*
1836          * Hmm.  We got an UDP packet to a port to which we
1837          * don't wanna listen.  Ignore it.
1838          */
1839         kfree_skb(skb);
1840         return 0;
1841 
1842 short_packet:
1843         net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1844                             proto == IPPROTO_UDPLITE ? "Lite" : "",
1845                             &saddr, ntohs(uh->source),
1846                             ulen, skb->len,
1847                             &daddr, ntohs(uh->dest));
1848         goto drop;
1849 
1850 csum_error:
1851         /*
1852          * RFC1122: OK.  Discards the bad packet silently (as far as
1853          * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1854          */
1855         net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1856                             proto == IPPROTO_UDPLITE ? "Lite" : "",
1857                             &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1858                             ulen);
1859         UDP_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
1860 drop:
1861         UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1862         kfree_skb(skb);
1863         return 0;
1864 }
1865 
1866 /* We can only early demux multicast if there is a single matching socket.
1867  * If more than one socket found returns NULL
1868  */
1869 static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
1870                                                   __be16 loc_port, __be32 loc_addr,
1871                                                   __be16 rmt_port, __be32 rmt_addr,
1872                                                   int dif)
1873 {
1874         struct sock *sk, *result;
1875         struct hlist_nulls_node *node;
1876         unsigned short hnum = ntohs(loc_port);
1877         unsigned int count, slot = udp_hashfn(net, hnum, udp_table.mask);
1878         struct udp_hslot *hslot = &udp_table.hash[slot];
1879 
1880         /* Do not bother scanning a too big list */
1881         if (hslot->count > 10)
1882                 return NULL;
1883 
1884         rcu_read_lock();
1885 begin:
1886         count = 0;
1887         result = NULL;
1888         sk_nulls_for_each_rcu(sk, node, &hslot->head) {
1889                 if (__udp_is_mcast_sock(net, sk,
1890                                         loc_port, loc_addr,
1891                                         rmt_port, rmt_addr,
1892                                         dif, hnum)) {
1893                         result = sk;
1894                         ++count;
1895                 }
1896         }
1897         /*
1898          * if the nulls value we got at the end of this lookup is
1899          * not the expected one, we must restart lookup.
1900          * We probably met an item that was moved to another chain.
1901          */
1902         if (get_nulls_value(node) != slot)
1903                 goto begin;
1904 
1905         if (result) {
1906                 if (count != 1 ||
1907                     unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1908                         result = NULL;
1909                 else if (unlikely(!__udp_is_mcast_sock(net, result,
1910                                                        loc_port, loc_addr,
1911                                                        rmt_port, rmt_addr,
1912                                                        dif, hnum))) {
1913                         sock_put(result);
1914                         result = NULL;
1915                 }
1916         }
1917         rcu_read_unlock();
1918         return result;
1919 }
1920 
1921 /* For unicast we should only early demux connected sockets or we can
1922  * break forwarding setups.  The chains here can be long so only check
1923  * if the first socket is an exact match and if not move on.
1924  */
1925 static struct sock *__udp4_lib_demux_lookup(struct net *net,
1926                                             __be16 loc_port, __be32 loc_addr,
1927                                             __be16 rmt_port, __be32 rmt_addr,
1928                                             int dif)
1929 {
1930         struct sock *sk, *result;
1931         struct hlist_nulls_node *node;
1932         unsigned short hnum = ntohs(loc_port);
1933         unsigned int hash2 = udp4_portaddr_hash(net, loc_addr, hnum);
1934         unsigned int slot2 = hash2 & udp_table.mask;
1935         struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
1936         INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
1937         const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
1938 
1939         rcu_read_lock();
1940         result = NULL;
1941         udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
1942                 if (INET_MATCH(sk, net, acookie,
1943                                rmt_addr, loc_addr, ports, dif))
1944                         result = sk;
1945                 /* Only check first socket in chain */
1946                 break;
1947         }
1948 
1949         if (result) {
1950                 if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1951                         result = NULL;
1952                 else if (unlikely(!INET_MATCH(sk, net, acookie,
1953                                               rmt_addr, loc_addr,
1954                                               ports, dif))) {
1955                         sock_put(result);
1956                         result = NULL;
1957                 }
1958         }
1959         rcu_read_unlock();
1960         return result;
1961 }
1962 
1963 void udp_v4_early_demux(struct sk_buff *skb)
1964 {
1965         struct net *net = dev_net(skb->dev);
1966         const struct iphdr *iph;
1967         const struct udphdr *uh;
1968         struct sock *sk;
1969         struct dst_entry *dst;
1970         int dif = skb->dev->ifindex;
1971 
1972         /* validate the packet */
1973         if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
1974                 return;
1975 
1976         iph = ip_hdr(skb);
1977         uh = udp_hdr(skb);
1978 
1979         if (skb->pkt_type == PACKET_BROADCAST ||
1980             skb->pkt_type == PACKET_MULTICAST)
1981                 sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
1982                                                    uh->source, iph->saddr, dif);
1983         else if (skb->pkt_type == PACKET_HOST)
1984                 sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
1985                                              uh->source, iph->saddr, dif);
1986         else
1987                 return;
1988 
1989         if (!sk)
1990                 return;
1991 
1992         skb->sk = sk;
1993         skb->destructor = sock_efree;
1994         dst = sk->sk_rx_dst;
1995 
1996         if (dst)
1997                 dst = dst_check(dst, 0);
1998         if (dst)
1999                 skb_dst_set_noref(skb, dst);
2000 }
2001 
2002 int udp_rcv(struct sk_buff *skb)
2003 {
2004         return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
2005 }
2006 
2007 void udp_destroy_sock(struct sock *sk)
2008 {
2009         struct udp_sock *up = udp_sk(sk);
2010         bool slow = lock_sock_fast(sk);
2011         udp_flush_pending_frames(sk);
2012         unlock_sock_fast(sk, slow);
2013         if (static_key_false(&udp_encap_needed) && up->encap_type) {
2014                 void (*encap_destroy)(struct sock *sk);
2015                 encap_destroy = ACCESS_ONCE(up->encap_destroy);
2016                 if (encap_destroy)
2017                         encap_destroy(sk);
2018         }
2019 }
2020 
2021 /*
2022  *      Socket option code for UDP
2023  */
2024 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
2025                        char __user *optval, unsigned int optlen,
2026                        int (*push_pending_frames)(struct sock *))
2027 {
2028         struct udp_sock *up = udp_sk(sk);
2029         int val, valbool;
2030         int err = 0;
2031         int is_udplite = IS_UDPLITE(sk);
2032 
2033         if (optlen < sizeof(int))
2034                 return -EINVAL;
2035 
2036         if (get_user(val, (int __user *)optval))
2037                 return -EFAULT;
2038 
2039         valbool = val ? 1 : 0;
2040 
2041         switch (optname) {
2042         case UDP_CORK:
2043                 if (val != 0) {
2044                         up->corkflag = 1;
2045                 } else {
2046                         up->corkflag = 0;
2047                         lock_sock(sk);
2048                         push_pending_frames(sk);
2049                         release_sock(sk);
2050                 }
2051                 break;
2052 
2053         case UDP_ENCAP:
2054                 switch (val) {
2055                 case 0:
2056                 case UDP_ENCAP_ESPINUDP:
2057                 case UDP_ENCAP_ESPINUDP_NON_IKE:
2058                         up->encap_rcv = xfrm4_udp_encap_rcv;
2059                         /* FALLTHROUGH */
2060                 case UDP_ENCAP_L2TPINUDP:
2061                         up->encap_type = val;
2062                         udp_encap_enable();
2063                         break;
2064                 default:
2065                         err = -ENOPROTOOPT;
2066                         break;
2067                 }
2068                 break;
2069 
2070         case UDP_NO_CHECK6_TX:
2071                 up->no_check6_tx = valbool;
2072                 break;
2073 
2074         case UDP_NO_CHECK6_RX:
2075                 up->no_check6_rx = valbool;
2076                 break;
2077 
2078         /*
2079          *      UDP-Lite's partial checksum coverage (RFC 3828).
2080          */
2081         /* The sender sets actual checksum coverage length via this option.
2082          * The case coverage > packet length is handled by send module. */
2083         case UDPLITE_SEND_CSCOV:
2084                 if (!is_udplite)         /* Disable the option on UDP sockets */
2085                         return -ENOPROTOOPT;
2086                 if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2087                         val = 8;
2088                 else if (val > USHRT_MAX)
2089                         val = USHRT_MAX;
2090                 up->pcslen = val;
2091                 up->pcflag |= UDPLITE_SEND_CC;
2092                 break;
2093 
2094         /* The receiver specifies a minimum checksum coverage value. To make
2095          * sense, this should be set to at least 8 (as done below). If zero is
2096          * used, this again means full checksum coverage.                     */
2097         case UDPLITE_RECV_CSCOV:
2098                 if (!is_udplite)         /* Disable the option on UDP sockets */
2099                         return -ENOPROTOOPT;
2100                 if (val != 0 && val < 8) /* Avoid silly minimal values.       */
2101                         val = 8;
2102                 else if (val > USHRT_MAX)
2103                         val = USHRT_MAX;
2104                 up->pcrlen = val;
2105                 up->pcflag |= UDPLITE_RECV_CC;
2106                 break;
2107 
2108         default:
2109                 err = -ENOPROTOOPT;
2110                 break;
2111         }
2112 
2113         return err;
2114 }
2115 EXPORT_SYMBOL(udp_lib_setsockopt);
2116 
2117 int udp_setsockopt(struct sock *sk, int level, int optname,
2118                    char __user *optval, unsigned int optlen)
2119 {
2120         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2121                 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2122                                           udp_push_pending_frames);
2123         return ip_setsockopt(sk, level, optname, optval, optlen);
2124 }
2125 
2126 #ifdef CONFIG_COMPAT
2127 int compat_udp_setsockopt(struct sock *sk, int level, int optname,
2128                           char __user *optval, unsigned int optlen)
2129 {
2130         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2131                 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2132                                           udp_push_pending_frames);
2133         return compat_ip_setsockopt(sk, level, optname, optval, optlen);
2134 }
2135 #endif
2136 
2137 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2138                        char __user *optval, int __user *optlen)
2139 {
2140         struct udp_sock *up = udp_sk(sk);
2141         int val, len;
2142 
2143         if (get_user(len, optlen))
2144                 return -EFAULT;
2145 
2146         len = min_t(unsigned int, len, sizeof(int));
2147 
2148         if (len < 0)
2149                 return -EINVAL;
2150 
2151         switch (optname) {
2152         case UDP_CORK:
2153                 val = up->corkflag;
2154                 break;
2155 
2156         case UDP_ENCAP:
2157                 val = up->encap_type;
2158                 break;
2159 
2160         case UDP_NO_CHECK6_TX:
2161                 val = up->no_check6_tx;
2162                 break;
2163 
2164         case UDP_NO_CHECK6_RX:
2165                 val = up->no_check6_rx;
2166                 break;
2167 
2168         /* The following two cannot be changed on UDP sockets, the return is
2169          * always 0 (which corresponds to the full checksum coverage of UDP). */
2170         case UDPLITE_SEND_CSCOV:
2171                 val = up->pcslen;
2172                 break;
2173 
2174         case UDPLITE_RECV_CSCOV:
2175                 val = up->pcrlen;
2176                 break;
2177 
2178         default:
2179                 return -ENOPROTOOPT;
2180         }
2181 
2182         if (put_user(len, optlen))
2183                 return -EFAULT;
2184         if (copy_to_user(optval, &val, len))
2185                 return -EFAULT;
2186         return 0;
2187 }
2188 EXPORT_SYMBOL(udp_lib_getsockopt);
2189 
2190 int udp_getsockopt(struct sock *sk, int level, int optname,
2191                    char __user *optval, int __user *optlen)
2192 {
2193         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2194                 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2195         return ip_getsockopt(sk, level, optname, optval, optlen);
2196 }
2197 
2198 #ifdef CONFIG_COMPAT
2199 int compat_udp_getsockopt(struct sock *sk, int level, int optname,
2200                                  char __user *optval, int __user *optlen)
2201 {
2202         if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2203                 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2204         return compat_ip_getsockopt(sk, level, optname, optval, optlen);
2205 }
2206 #endif
2207 /**
2208  *      udp_poll - wait for a UDP event.
2209  *      @file - file struct
2210  *      @sock - socket
2211  *      @wait - poll table
2212  *
2213  *      This is same as datagram poll, except for the special case of
2214  *      blocking sockets. If application is using a blocking fd
2215  *      and a packet with checksum error is in the queue;
2216  *      then it could get return from select indicating data available
2217  *      but then block when reading it. Add special case code
2218  *      to work around these arguably broken applications.
2219  */
2220 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2221 {
2222         unsigned int mask = datagram_poll(file, sock, wait);
2223         struct sock *sk = sock->sk;
2224 
2225         sock_rps_record_flow(sk);
2226 
2227         /* Check for false positives due to checksum errors */
2228         if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2229             !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
2230                 mask &= ~(POLLIN | POLLRDNORM);
2231 
2232         return mask;
2233 
2234 }
2235 EXPORT_SYMBOL(udp_poll);
2236 
2237 struct proto udp_prot = {
2238         .name              = "UDP",
2239         .owner             = THIS_MODULE,
2240         .close             = udp_lib_close,
2241         .connect           = ip4_datagram_connect,
2242         .disconnect        = udp_disconnect,
2243         .ioctl             = udp_ioctl,
2244         .destroy           = udp_destroy_sock,
2245         .setsockopt        = udp_setsockopt,
2246         .getsockopt        = udp_getsockopt,
2247         .sendmsg           = udp_sendmsg,
2248         .recvmsg           = udp_recvmsg,
2249         .sendpage          = udp_sendpage,
2250         .backlog_rcv       = __udp_queue_rcv_skb,
2251         .release_cb        = ip4_datagram_release_cb,
2252         .hash              = udp_lib_hash,
2253         .unhash            = udp_lib_unhash,
2254         .rehash            = udp_v4_rehash,
2255         .get_port          = udp_v4_get_port,
2256         .memory_allocated  = &udp_memory_allocated,
2257         .sysctl_mem        = sysctl_udp_mem,
2258         .sysctl_wmem       = &sysctl_udp_wmem_min,
2259         .sysctl_rmem       = &sysctl_udp_rmem_min,
2260         .obj_size          = sizeof(struct udp_sock),
2261         .slab_flags        = SLAB_DESTROY_BY_RCU,
2262         .h.udp_table       = &udp_table,
2263 #ifdef CONFIG_COMPAT
2264         .compat_setsockopt = compat_udp_setsockopt,
2265         .compat_getsockopt = compat_udp_getsockopt,
2266 #endif
2267         .clear_sk          = sk_prot_clear_portaddr_nulls,
2268 };
2269 EXPORT_SYMBOL(udp_prot);
2270 
2271 /* ------------------------------------------------------------------------ */
2272 #ifdef CONFIG_PROC_FS
2273 
2274 static struct sock *udp_get_first(struct seq_file *seq, int start)
2275 {
2276         struct sock *sk;
2277         struct udp_iter_state *state = seq->private;
2278         struct net *net = seq_file_net(seq);
2279 
2280         for (state->bucket = start; state->bucket <= state->udp_table->mask;
2281              ++state->bucket) {
2282                 struct hlist_nulls_node *node;
2283                 struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
2284 
2285                 if (hlist_nulls_empty(&hslot->head))
2286                         continue;
2287 
2288                 spin_lock_bh(&hslot->lock);
2289                 sk_nulls_for_each(sk, node, &hslot->head) {
2290                         if (!net_eq(sock_net(sk), net))
2291                                 continue;
2292                         if (sk->sk_family == state->family)
2293                                 goto found;
2294                 }
2295                 spin_unlock_bh(&hslot->lock);
2296         }
2297         sk = NULL;
2298 found:
2299         return sk;
2300 }
2301 
2302 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
2303 {
2304         struct udp_iter_state *state = seq->private;
2305         struct net *net = seq_file_net(seq);
2306 
2307         do {
2308                 sk = sk_nulls_next(sk);
2309         } while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2310 
2311         if (!sk) {
2312                 if (state->bucket <= state->udp_table->mask)
2313                         spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2314                 return udp_get_first(seq, state->bucket + 1);
2315         }
2316         return sk;
2317 }
2318 
2319 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2320 {
2321         struct sock *sk = udp_get_first(seq, 0);
2322 
2323         if (sk)
2324                 while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2325                         --pos;
2326         return pos ? NULL : sk;
2327 }
2328 
2329 static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2330 {
2331         struct udp_iter_state *state = seq->private;
2332         state->bucket = MAX_UDP_PORTS;
2333 
2334         return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2335 }
2336 
2337 static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2338 {
2339         struct sock *sk;
2340 
2341         if (v == SEQ_START_TOKEN)
2342                 sk = udp_get_idx(seq, 0);
2343         else
2344                 sk = udp_get_next(seq, v);
2345 
2346         ++*pos;
2347         return sk;
2348 }
2349 
2350 static void udp_seq_stop(struct seq_file *seq, void *v)
2351 {
2352         struct udp_iter_state *state = seq->private;
2353 
2354         if (state->bucket <= state->udp_table->mask)
2355                 spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2356 }
2357 
2358 int udp_seq_open(struct inode *inode, struct file *file)
2359 {
2360         struct udp_seq_afinfo *afinfo = PDE_DATA(inode);
2361         struct udp_iter_state *s;
2362         int err;
2363 
2364         err = seq_open_net(inode, file, &afinfo->seq_ops,
2365                            sizeof(struct udp_iter_state));
2366         if (err < 0)
2367                 return err;
2368 
2369         s = ((struct seq_file *)file->private_data)->private;
2370         s->family               = afinfo->family;
2371         s->udp_table            = afinfo->udp_table;
2372         return err;
2373 }
2374 EXPORT_SYMBOL(udp_seq_open);
2375 
2376 /* ------------------------------------------------------------------------ */
2377 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2378 {
2379         struct proc_dir_entry *p;
2380         int rc = 0;
2381 
2382         afinfo->seq_ops.start           = udp_seq_start;
2383         afinfo->seq_ops.next            = udp_seq_next;
2384         afinfo->seq_ops.stop            = udp_seq_stop;
2385 
2386         p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2387                              afinfo->seq_fops, afinfo);
2388         if (!p)
2389                 rc = -ENOMEM;
2390         return rc;
2391 }
2392 EXPORT_SYMBOL(udp_proc_register);
2393 
2394 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2395 {
2396         remove_proc_entry(afinfo->name, net->proc_net);
2397 }
2398 EXPORT_SYMBOL(udp_proc_unregister);
2399 
2400 /* ------------------------------------------------------------------------ */
2401 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2402                 int bucket)
2403 {
2404         struct inet_sock *inet = inet_sk(sp);
2405         __be32 dest = inet->inet_daddr;
2406         __be32 src  = inet->inet_rcv_saddr;
2407         __u16 destp       = ntohs(inet->inet_dport);
2408         __u16 srcp        = ntohs(inet->inet_sport);
2409 
2410         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2411                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
2412                 bucket, src, srcp, dest, destp, sp->sk_state,
2413                 sk_wmem_alloc_get(sp),
2414                 sk_rmem_alloc_get(sp),
2415                 0, 0L, 0,
2416                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
2417                 0, sock_i_ino(sp),
2418                 atomic_read(&sp->sk_refcnt), sp,
2419                 atomic_read(&sp->sk_drops));
2420 }
2421 
2422 int udp4_seq_show(struct seq_file *seq, void *v)
2423 {
2424         seq_setwidth(seq, 127);
2425         if (v == SEQ_START_TOKEN)
2426                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
2427                            "rx_queue tr tm->when retrnsmt   uid  timeout "
2428                            "inode ref pointer drops");
2429         else {
2430                 struct udp_iter_state *state = seq->private;
2431 
2432                 udp4_format_sock(v, seq, state->bucket);
2433         }
2434         seq_pad(seq, '\n');
2435         return 0;
2436 }
2437 
2438 static const struct file_operations udp_afinfo_seq_fops = {
2439         .owner    = THIS_MODULE,
2440         .open     = udp_seq_open,
2441         .read     = seq_read,
2442         .llseek   = seq_lseek,
2443         .release  = seq_release_net
2444 };
2445 
2446 /* ------------------------------------------------------------------------ */
2447 static struct udp_seq_afinfo udp4_seq_afinfo = {
2448         .name           = "udp",
2449         .family         = AF_INET,
2450         .udp_table      = &udp_table,
2451         .seq_fops       = &udp_afinfo_seq_fops,
2452         .seq_ops        = {
2453                 .show           = udp4_seq_show,
2454         },
2455 };
2456 
2457 static int __net_init udp4_proc_init_net(struct net *net)
2458 {
2459         return udp_proc_register(net, &udp4_seq_afinfo);
2460 }
2461 
2462 static void __net_exit udp4_proc_exit_net(struct net *net)
2463 {
2464         udp_proc_unregister(net, &udp4_seq_afinfo);
2465 }
2466 
2467 static struct pernet_operations udp4_net_ops = {
2468         .init = udp4_proc_init_net,
2469         .exit = udp4_proc_exit_net,
2470 };
2471 
2472 int __init udp4_proc_init(void)
2473 {
2474         return register_pernet_subsys(&udp4_net_ops);
2475 }
2476 
2477 void udp4_proc_exit(void)
2478 {
2479         unregister_pernet_subsys(&udp4_net_ops);
2480 }
2481 #endif /* CONFIG_PROC_FS */
2482 
2483 static __initdata unsigned long uhash_entries;
2484 static int __init set_uhash_entries(char *str)
2485 {
2486         ssize_t ret;
2487 
2488         if (!str)
2489                 return 0;
2490 
2491         ret = kstrtoul(str, 0, &uhash_entries);
2492         if (ret)
2493                 return 0;
2494 
2495         if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2496                 uhash_entries = UDP_HTABLE_SIZE_MIN;
2497         return 1;
2498 }
2499 __setup("uhash_entries=", set_uhash_entries);
2500 
2501 void __init udp_table_init(struct udp_table *table, const char *name)
2502 {
2503         unsigned int i;
2504 
2505         table->hash = alloc_large_system_hash(name,
2506                                               2 * sizeof(struct udp_hslot),
2507                                               uhash_entries,
2508                                               21, /* one slot per 2 MB */
2509                                               0,
2510                                               &table->log,
2511                                               &table->mask,
2512                                               UDP_HTABLE_SIZE_MIN,
2513                                               64 * 1024);
2514 
2515         table->hash2 = table->hash + (table->mask + 1);
2516         for (i = 0; i <= table->mask; i++) {
2517                 INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2518                 table->hash[i].count = 0;
2519                 spin_lock_init(&table->hash[i].lock);
2520         }
2521         for (i = 0; i <= table->mask; i++) {
2522                 INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2523                 table->hash2[i].count = 0;
2524                 spin_lock_init(&table->hash2[i].lock);
2525         }
2526 }
2527 
2528 void __init udp_init(void)
2529 {
2530         unsigned long limit;
2531 
2532         udp_table_init(&udp_table, "UDP");
2533         limit = nr_free_buffer_pages() / 8;
2534         limit = max(limit, 128UL);
2535         sysctl_udp_mem[0] = limit / 4 * 3;
2536         sysctl_udp_mem[1] = limit;
2537         sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2538 
2539         sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2540         sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2541 }
2542 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us