1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * The User Datagram Protocol (UDP).
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
12 * Alan Cox, <alan@lxorguk.ukuu.org.uk>
13 * Hirokazu Takahashi, <taka@valinux.co.jp>
14 *
15 * Fixes:
16 * Alan Cox : verify_area() calls
17 * Alan Cox : stopped close while in use off icmp
18 * messages. Not a fix but a botch that
19 * for udp at least is 'valid'.
20 * Alan Cox : Fixed icmp handling properly
21 * Alan Cox : Correct error for oversized datagrams
22 * Alan Cox : Tidied select() semantics.
23 * Alan Cox : udp_err() fixed properly, also now
24 * select and read wake correctly on errors
25 * Alan Cox : udp_send verify_area moved to avoid mem leak
26 * Alan Cox : UDP can count its memory
27 * Alan Cox : send to an unknown connection causes
28 * an ECONNREFUSED off the icmp, but
29 * does NOT close.
30 * Alan Cox : Switched to new sk_buff handlers. No more backlog!
31 * Alan Cox : Using generic datagram code. Even smaller and the PEEK
32 * bug no longer crashes it.
33 * Fred Van Kempen : Net2e support for sk->broadcast.
34 * Alan Cox : Uses skb_free_datagram
35 * Alan Cox : Added get/set sockopt support.
36 * Alan Cox : Broadcasting without option set returns EACCES.
37 * Alan Cox : No wakeup calls. Instead we now use the callbacks.
38 * Alan Cox : Use ip_tos and ip_ttl
39 * Alan Cox : SNMP Mibs
40 * Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support.
41 * Matt Dillon : UDP length checks.
42 * Alan Cox : Smarter af_inet used properly.
43 * Alan Cox : Use new kernel side addressing.
44 * Alan Cox : Incorrect return on truncated datagram receive.
45 * Arnt Gulbrandsen : New udp_send and stuff
46 * Alan Cox : Cache last socket
47 * Alan Cox : Route cache
48 * Jon Peatfield : Minor efficiency fix to sendto().
49 * Mike Shaver : RFC1122 checks.
50 * Alan Cox : Nonblocking error fix.
51 * Willy Konynenberg : Transparent proxying support.
52 * Mike McLagan : Routing by source
53 * David S. Miller : New socket lookup architecture.
54 * Last socket cache retained as it
55 * does have a high hit rate.
56 * Olaf Kirch : Don't linearise iovec on sendmsg.
57 * Andi Kleen : Some cleanups, cache destination entry
58 * for connect.
59 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
60 * Melvin Smith : Check msg_name not msg_namelen in sendto(),
61 * return ENOTCONN for unconnected sockets (POSIX)
62 * Janos Farkas : don't deliver multi/broadcasts to a different
63 * bound-to-device socket
64 * Hirokazu Takahashi : HW checksumming for outgoing UDP
65 * datagrams.
66 * Hirokazu Takahashi : sendfile() on UDP works now.
67 * Arnaldo C. Melo : convert /proc/net/udp to seq_file
68 * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
69 * Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind
70 * a single port at the same time.
71 * Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
72 * James Chapman : Add L2TP encapsulation type.
73 */
74
75 #define pr_fmt(fmt) "UDP: " fmt
76
77 #include <linux/bpf-cgroup.h>
78 #include <linux/uaccess.h>
79 #include <asm/ioctls.h>
80 #include <linux/memblock.h>
81 #include <linux/highmem.h>
82 #include <linux/types.h>
83 #include <linux/fcntl.h>
84 #include <linux/module.h>
85 #include <linux/socket.h>
86 #include <linux/sockios.h>
87 #include <linux/igmp.h>
88 #include <linux/inetdevice.h>
89 #include <linux/in.h>
90 #include <linux/errno.h>
91 #include <linux/timer.h>
92 #include <linux/mm.h>
93 #include <linux/inet.h>
94 #include <linux/netdevice.h>
95 #include <linux/slab.h>
96 #include <net/tcp_states.h>
97 #include <linux/skbuff.h>
98 #include <linux/proc_fs.h>
99 #include <linux/seq_file.h>
100 #include <net/net_namespace.h>
101 #include <net/icmp.h>
102 #include <net/inet_hashtables.h>
103 #include <net/ip_tunnels.h>
104 #include <net/route.h>
105 #include <net/checksum.h>
106 #include <net/gso.h>
107 #include <net/xfrm.h>
108 #include <trace/events/udp.h>
109 #include <linux/static_key.h>
110 #include <linux/btf_ids.h>
111 #include <trace/events/skb.h>
112 #include <net/busy_poll.h>
113 #include "udp_impl.h"
114 #include <net/sock_reuseport.h>
115 #include <net/addrconf.h>
116 #include <net/udp_tunnel.h>
117 #include <net/gro.h>
118 #if IS_ENABLED(CONFIG_IPV6)
119 #include <net/ipv6_stubs.h>
120 #endif
121
122 struct udp_table udp_table __read_mostly;
123 EXPORT_SYMBOL(udp_table);
124
125 long sysctl_udp_mem[3] __read_mostly;
126 EXPORT_SYMBOL(sysctl_udp_mem);
127
128 atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
129 EXPORT_SYMBOL(udp_memory_allocated);
130 DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
131 EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc);
132
133 #define MAX_UDP_PORTS 65536
134 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN_PERNET)
135
136 static struct udp_table *udp_get_table_prot(struct sock *sk)
137 {
138 return sk->sk_prot->h.udp_table ? : sock_net(sk)->ipv4.udp_table;
139 }
140
141 static int udp_lib_lport_inuse(struct net *net, __u16 num,
142 const struct udp_hslot *hslot,
143 unsigned long *bitmap,
144 struct sock *sk, unsigned int log)
145 {
146 struct sock *sk2;
147 kuid_t uid = sock_i_uid(sk);
148
149 sk_for_each(sk2, &hslot->head) {
150 if (net_eq(sock_net(sk2), net) &&
151 sk2 != sk &&
152 (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
153 (!sk2->sk_reuse || !sk->sk_reuse) &&
154 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
155 sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
156 inet_rcv_saddr_equal(sk, sk2, true)) {
157 if (sk2->sk_reuseport && sk->sk_reuseport &&
158 !rcu_access_pointer(sk->sk_reuseport_cb) &&
159 uid_eq(uid, sock_i_uid(sk2))) {
160 if (!bitmap)
161 return 0;
162 } else {
163 if (!bitmap)
164 return 1;
165 __set_bit(udp_sk(sk2)->udp_port_hash >> log,
166 bitmap);
167 }
168 }
169 }
170 return 0;
171 }
172
173 /*
174 * Note: we still hold spinlock of primary hash chain, so no other writer
175 * can insert/delete a socket with local_port == num
176 */
177 static int udp_lib_lport_inuse2(struct net *net, __u16 num,
178 struct udp_hslot *hslot2,
179 struct sock *sk)
180 {
181 struct sock *sk2;
182 kuid_t uid = sock_i_uid(sk);
183 int res = 0;
184
185 spin_lock(&hslot2->lock);
186 udp_portaddr_for_each_entry(sk2, &hslot2->head) {
187 if (net_eq(sock_net(sk2), net) &&
188 sk2 != sk &&
189 (udp_sk(sk2)->udp_port_hash == num) &&
190 (!sk2->sk_reuse || !sk->sk_reuse) &&
191 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
192 sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
193 inet_rcv_saddr_equal(sk, sk2, true)) {
194 if (sk2->sk_reuseport && sk->sk_reuseport &&
195 !rcu_access_pointer(sk->sk_reuseport_cb) &&
196 uid_eq(uid, sock_i_uid(sk2))) {
197 res = 0;
198 } else {
199 res = 1;
200 }
201 break;
202 }
203 }
204 spin_unlock(&hslot2->lock);
205 return res;
206 }
207
208 static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
209 {
210 struct net *net = sock_net(sk);
211 kuid_t uid = sock_i_uid(sk);
212 struct sock *sk2;
213
214 sk_for_each(sk2, &hslot->head) {
215 if (net_eq(sock_net(sk2), net) &&
216 sk2 != sk &&
217 sk2->sk_family == sk->sk_family &&
218 ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
219 (udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
220 (sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
221 sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
222 inet_rcv_saddr_equal(sk, sk2, false)) {
223 return reuseport_add_sock(sk, sk2,
224 inet_rcv_saddr_any(sk));
225 }
226 }
227
228 return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
229 }
230
231 /**
232 * udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
233 *
234 * @sk: socket struct in question
235 * @snum: port number to look up
236 * @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
237 * with NULL address
238 */
239 int udp_lib_get_port(struct sock *sk, unsigned short snum,
240 unsigned int hash2_nulladdr)
241 {
242 struct udp_table *udptable = udp_get_table_prot(sk);
243 struct udp_hslot *hslot, *hslot2;
244 struct net *net = sock_net(sk);
245 int error = -EADDRINUSE;
246
247 if (!snum) {
248 DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
249 unsigned short first, last;
250 int low, high, remaining;
251 unsigned int rand;
252
253 inet_sk_get_local_port_range(sk, &low, &high);
254 remaining = (high - low) + 1;
255
256 rand = get_random_u32();
257 first = reciprocal_scale(rand, remaining) + low;
258 /*
259 * force rand to be an odd multiple of UDP_HTABLE_SIZE
260 */
261 rand = (rand | 1) * (udptable->mask + 1);
262 last = first + udptable->mask + 1;
263 do {
264 hslot = udp_hashslot(udptable, net, first);
265 bitmap_zero(bitmap, PORTS_PER_CHAIN);
266 spin_lock_bh(&hslot->lock);
267 udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
268 udptable->log);
269
270 snum = first;
271 /*
272 * Iterate on all possible values of snum for this hash.
273 * Using steps of an odd multiple of UDP_HTABLE_SIZE
274 * give us randomization and full range coverage.
275 */
276 do {
277 if (low <= snum && snum <= high &&
278 !test_bit(snum >> udptable->log, bitmap) &&
279 !inet_is_local_reserved_port(net, snum))
280 goto found;
281 snum += rand;
282 } while (snum != first);
283 spin_unlock_bh(&hslot->lock);
284 cond_resched();
285 } while (++first != last);
286 goto fail;
287 } else {
288 hslot = udp_hashslot(udptable, net, snum);
289 spin_lock_bh(&hslot->lock);
290 if (hslot->count > 10) {
291 int exist;
292 unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
293
294 slot2 &= udptable->mask;
295 hash2_nulladdr &= udptable->mask;
296
297 hslot2 = udp_hashslot2(udptable, slot2);
298 if (hslot->count < hslot2->count)
299 goto scan_primary_hash;
300
301 exist = udp_lib_lport_inuse2(net, snum, hslot2, sk);
302 if (!exist && (hash2_nulladdr != slot2)) {
303 hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
304 exist = udp_lib_lport_inuse2(net, snum, hslot2,
305 sk);
306 }
307 if (exist)
308 goto fail_unlock;
309 else
310 goto found;
311 }
312 scan_primary_hash:
313 if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 0))
314 goto fail_unlock;
315 }
316 found:
317 inet_sk(sk)->inet_num = snum;
318 udp_sk(sk)->udp_port_hash = snum;
319 udp_sk(sk)->udp_portaddr_hash ^= snum;
320 if (sk_unhashed(sk)) {
321 if (sk->sk_reuseport &&
322 udp_reuseport_add_sock(sk, hslot)) {
323 inet_sk(sk)->inet_num = 0;
324 udp_sk(sk)->udp_port_hash = 0;
325 udp_sk(sk)->udp_portaddr_hash ^= snum;
326 goto fail_unlock;
327 }
328
329 sock_set_flag(sk, SOCK_RCU_FREE);
330
331 sk_add_node_rcu(sk, &hslot->head);
332 hslot->count++;
333 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
334
335 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
336 spin_lock(&hslot2->lock);
337 if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
338 sk->sk_family == AF_INET6)
339 hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
340 &hslot2->head);
341 else
342 hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
343 &hslot2->head);
344 hslot2->count++;
345 spin_unlock(&hslot2->lock);
346 }
347
348 error = 0;
349 fail_unlock:
350 spin_unlock_bh(&hslot->lock);
351 fail:
352 return error;
353 }
354 EXPORT_SYMBOL(udp_lib_get_port);
355
356 int udp_v4_get_port(struct sock *sk, unsigned short snum)
357 {
358 unsigned int hash2_nulladdr =
359 ipv4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
360 unsigned int hash2_partial =
361 ipv4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
362
363 /* precompute partial secondary hash */
364 udp_sk(sk)->udp_portaddr_hash = hash2_partial;
365 return udp_lib_get_port(sk, snum, hash2_nulladdr);
366 }
367
368 static int compute_score(struct sock *sk, struct net *net,
369 __be32 saddr, __be16 sport,
370 __be32 daddr, unsigned short hnum,
371 int dif, int sdif)
372 {
373 int score;
374 struct inet_sock *inet;
375 bool dev_match;
376
377 if (!net_eq(sock_net(sk), net) ||
378 udp_sk(sk)->udp_port_hash != hnum ||
379 ipv6_only_sock(sk))
380 return -1;
381
382 if (sk->sk_rcv_saddr != daddr)
383 return -1;
384
385 score = (sk->sk_family == PF_INET) ? 2 : 1;
386
387 inet = inet_sk(sk);
388 if (inet->inet_daddr) {
389 if (inet->inet_daddr != saddr)
390 return -1;
391 score += 4;
392 }
393
394 if (inet->inet_dport) {
395 if (inet->inet_dport != sport)
396 return -1;
397 score += 4;
398 }
399
400 dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if,
401 dif, sdif);
402 if (!dev_match)
403 return -1;
404 if (sk->sk_bound_dev_if)
405 score += 4;
406
407 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
408 score++;
409 return score;
410 }
411
412 INDIRECT_CALLABLE_SCOPE
413 u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
414 const __be32 faddr, const __be16 fport)
415 {
416 net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
417
418 return __inet_ehashfn(laddr, lport, faddr, fport,
419 udp_ehash_secret + net_hash_mix(net));
420 }
421
422 /* called with rcu_read_lock() */
423 static struct sock *udp4_lib_lookup2(struct net *net,
424 __be32 saddr, __be16 sport,
425 __be32 daddr, unsigned int hnum,
426 int dif, int sdif,
427 struct udp_hslot *hslot2,
428 struct sk_buff *skb)
429 {
430 struct sock *sk, *result;
431 int score, badness;
432 bool need_rescore;
433
434 result = NULL;
435 badness = 0;
436 udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
437 need_rescore = false;
438 rescore:
439 score = compute_score(need_rescore ? result : sk, net, saddr,
440 sport, daddr, hnum, dif, sdif);
441 if (score > badness) {
442 badness = score;
443
444 if (need_rescore)
445 continue;
446
447 if (sk->sk_state == TCP_ESTABLISHED) {
448 result = sk;
449 continue;
450 }
451
452 result = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
453 saddr, sport, daddr, hnum, udp_ehashfn);
454 if (!result) {
455 result = sk;
456 continue;
457 }
458
459 /* Fall back to scoring if group has connections */
460 if (!reuseport_has_conns(sk))
461 return result;
462
463 /* Reuseport logic returned an error, keep original score. */
464 if (IS_ERR(result))
465 continue;
466
467 /* compute_score is too long of a function to be
468 * inlined, and calling it again here yields
469 * measureable overhead for some
470 * workloads. Work around it by jumping
471 * backwards to rescore 'result'.
472 */
473 need_rescore = true;
474 goto rescore;
475 }
476 }
477 return result;
478 }
479
480 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
481 * harder than this. -DaveM
482 */
483 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
484 __be16 sport, __be32 daddr, __be16 dport, int dif,
485 int sdif, struct udp_table *udptable, struct sk_buff *skb)
486 {
487 unsigned short hnum = ntohs(dport);
488 unsigned int hash2, slot2;
489 struct udp_hslot *hslot2;
490 struct sock *result, *sk;
491
492 hash2 = ipv4_portaddr_hash(net, daddr, hnum);
493 slot2 = hash2 & udptable->mask;
494 hslot2 = &udptable->hash2[slot2];
495
496 /* Lookup connected or non-wildcard socket */
497 result = udp4_lib_lookup2(net, saddr, sport,
498 daddr, hnum, dif, sdif,
499 hslot2, skb);
500 if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED)
501 goto done;
502
503 /* Lookup redirect from BPF */
504 if (static_branch_unlikely(&bpf_sk_lookup_enabled) &&
505 udptable == net->ipv4.udp_table) {
506 sk = inet_lookup_run_sk_lookup(net, IPPROTO_UDP, skb, sizeof(struct udphdr),
507 saddr, sport, daddr, hnum, dif,
508 udp_ehashfn);
509 if (sk) {
510 result = sk;
511 goto done;
512 }
513 }
514
515 /* Got non-wildcard socket or error on first lookup */
516 if (result)
517 goto done;
518
519 /* Lookup wildcard sockets */
520 hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
521 slot2 = hash2 & udptable->mask;
522 hslot2 = &udptable->hash2[slot2];
523
524 result = udp4_lib_lookup2(net, saddr, sport,
525 htonl(INADDR_ANY), hnum, dif, sdif,
526 hslot2, skb);
527 done:
528 if (IS_ERR(result))
529 return NULL;
530 return result;
531 }
532 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
533
534 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
535 __be16 sport, __be16 dport,
536 struct udp_table *udptable)
537 {
538 const struct iphdr *iph = ip_hdr(skb);
539
540 return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
541 iph->daddr, dport, inet_iif(skb),
542 inet_sdif(skb), udptable, skb);
543 }
544
545 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
546 __be16 sport, __be16 dport)
547 {
548 const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
549 const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
550 struct net *net = dev_net(skb->dev);
551 int iif, sdif;
552
553 inet_get_iif_sdif(skb, &iif, &sdif);
554
555 return __udp4_lib_lookup(net, iph->saddr, sport,
556 iph->daddr, dport, iif,
557 sdif, net->ipv4.udp_table, NULL);
558 }
559
560 /* Must be called under rcu_read_lock().
561 * Does increment socket refcount.
562 */
563 #if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) || IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
564 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
565 __be32 daddr, __be16 dport, int dif)
566 {
567 struct sock *sk;
568
569 sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
570 dif, 0, net->ipv4.udp_table, NULL);
571 if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
572 sk = NULL;
573 return sk;
574 }
575 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
576 #endif
577
578 static inline bool __udp_is_mcast_sock(struct net *net, const struct sock *sk,
579 __be16 loc_port, __be32 loc_addr,
580 __be16 rmt_port, __be32 rmt_addr,
581 int dif, int sdif, unsigned short hnum)
582 {
583 const struct inet_sock *inet = inet_sk(sk);
584
585 if (!net_eq(sock_net(sk), net) ||
586 udp_sk(sk)->udp_port_hash != hnum ||
587 (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
588 (inet->inet_dport != rmt_port && inet->inet_dport) ||
589 (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
590 ipv6_only_sock(sk) ||
591 !udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
592 return false;
593 if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif))
594 return false;
595 return true;
596 }
597
598 DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
599 EXPORT_SYMBOL(udp_encap_needed_key);
600
601 #if IS_ENABLED(CONFIG_IPV6)
602 DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
603 EXPORT_SYMBOL(udpv6_encap_needed_key);
604 #endif
605
606 void udp_encap_enable(void)
607 {
608 static_branch_inc(&udp_encap_needed_key);
609 }
610 EXPORT_SYMBOL(udp_encap_enable);
611
612 void udp_encap_disable(void)
613 {
614 static_branch_dec(&udp_encap_needed_key);
615 }
616 EXPORT_SYMBOL(udp_encap_disable);
617
618 /* Handler for tunnels with arbitrary destination ports: no socket lookup, go
619 * through error handlers in encapsulations looking for a match.
620 */
621 static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
622 {
623 int i;
624
625 for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
626 int (*handler)(struct sk_buff *skb, u32 info);
627 const struct ip_tunnel_encap_ops *encap;
628
629 encap = rcu_dereference(iptun_encaps[i]);
630 if (!encap)
631 continue;
632 handler = encap->err_handler;
633 if (handler && !handler(skb, info))
634 return 0;
635 }
636
637 return -ENOENT;
638 }
639
640 /* Try to match ICMP errors to UDP tunnels by looking up a socket without
641 * reversing source and destination port: this will match tunnels that force the
642 * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
643 * lwtunnels might actually break this assumption by being configured with
644 * different destination ports on endpoints, in this case we won't be able to
645 * trace ICMP messages back to them.
646 *
647 * If this doesn't match any socket, probe tunnels with arbitrary destination
648 * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
649 * we've sent packets to won't necessarily match the local destination port.
650 *
651 * Then ask the tunnel implementation to match the error against a valid
652 * association.
653 *
654 * Return an error if we can't find a match, the socket if we need further
655 * processing, zero otherwise.
656 */
657 static struct sock *__udp4_lib_err_encap(struct net *net,
658 const struct iphdr *iph,
659 struct udphdr *uh,
660 struct udp_table *udptable,
661 struct sock *sk,
662 struct sk_buff *skb, u32 info)
663 {
664 int (*lookup)(struct sock *sk, struct sk_buff *skb);
665 int network_offset, transport_offset;
666 struct udp_sock *up;
667
668 network_offset = skb_network_offset(skb);
669 transport_offset = skb_transport_offset(skb);
670
671 /* Network header needs to point to the outer IPv4 header inside ICMP */
672 skb_reset_network_header(skb);
673
674 /* Transport header needs to point to the UDP header */
675 skb_set_transport_header(skb, iph->ihl << 2);
676
677 if (sk) {
678 up = udp_sk(sk);
679
680 lookup = READ_ONCE(up->encap_err_lookup);
681 if (lookup && lookup(sk, skb))
682 sk = NULL;
683
684 goto out;
685 }
686
687 sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
688 iph->saddr, uh->dest, skb->dev->ifindex, 0,
689 udptable, NULL);
690 if (sk) {
691 up = udp_sk(sk);
692
693 lookup = READ_ONCE(up->encap_err_lookup);
694 if (!lookup || lookup(sk, skb))
695 sk = NULL;
696 }
697
698 out:
699 if (!sk)
700 sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
701
702 skb_set_transport_header(skb, transport_offset);
703 skb_set_network_header(skb, network_offset);
704
705 return sk;
706 }
707
708 /*
709 * This routine is called by the ICMP module when it gets some
710 * sort of error condition. If err < 0 then the socket should
711 * be closed and the error returned to the user. If err > 0
712 * it's just the icmp type << 8 | icmp code.
713 * Header points to the ip header of the error packet. We move
714 * on past this. Then (as it used to claim before adjustment)
715 * header points to the first 8 bytes of the udp header. We need
716 * to find the appropriate port.
717 */
718
719 int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
720 {
721 struct inet_sock *inet;
722 const struct iphdr *iph = (const struct iphdr *)skb->data;
723 struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
724 const int type = icmp_hdr(skb)->type;
725 const int code = icmp_hdr(skb)->code;
726 bool tunnel = false;
727 struct sock *sk;
728 int harderr;
729 int err;
730 struct net *net = dev_net(skb->dev);
731
732 sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
733 iph->saddr, uh->source, skb->dev->ifindex,
734 inet_sdif(skb), udptable, NULL);
735
736 if (!sk || READ_ONCE(udp_sk(sk)->encap_type)) {
737 /* No socket for error: try tunnels before discarding */
738 if (static_branch_unlikely(&udp_encap_needed_key)) {
739 sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb,
740 info);
741 if (!sk)
742 return 0;
743 } else
744 sk = ERR_PTR(-ENOENT);
745
746 if (IS_ERR(sk)) {
747 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
748 return PTR_ERR(sk);
749 }
750
751 tunnel = true;
752 }
753
754 err = 0;
755 harderr = 0;
756 inet = inet_sk(sk);
757
758 switch (type) {
759 default:
760 case ICMP_TIME_EXCEEDED:
761 err = EHOSTUNREACH;
762 break;
763 case ICMP_SOURCE_QUENCH:
764 goto out;
765 case ICMP_PARAMETERPROB:
766 err = EPROTO;
767 harderr = 1;
768 break;
769 case ICMP_DEST_UNREACH:
770 if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
771 ipv4_sk_update_pmtu(skb, sk, info);
772 if (READ_ONCE(inet->pmtudisc) != IP_PMTUDISC_DONT) {
773 err = EMSGSIZE;
774 harderr = 1;
775 break;
776 }
777 goto out;
778 }
779 err = EHOSTUNREACH;
780 if (code <= NR_ICMP_UNREACH) {
781 harderr = icmp_err_convert[code].fatal;
782 err = icmp_err_convert[code].errno;
783 }
784 break;
785 case ICMP_REDIRECT:
786 ipv4_sk_redirect(skb, sk);
787 goto out;
788 }
789
790 /*
791 * RFC1122: OK. Passes ICMP errors back to application, as per
792 * 4.1.3.3.
793 */
794 if (tunnel) {
795 /* ...not for tunnels though: we don't have a sending socket */
796 if (udp_sk(sk)->encap_err_rcv)
797 udp_sk(sk)->encap_err_rcv(sk, skb, err, uh->dest, info,
798 (u8 *)(uh+1));
799 goto out;
800 }
801 if (!inet_test_bit(RECVERR, sk)) {
802 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
803 goto out;
804 } else
805 ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
806
807 sk->sk_err = err;
808 sk_error_report(sk);
809 out:
810 return 0;
811 }
812
813 int udp_err(struct sk_buff *skb, u32 info)
814 {
815 return __udp4_lib_err(skb, info, dev_net(skb->dev)->ipv4.udp_table);
816 }
817
818 /*
819 * Throw away all pending data and cancel the corking. Socket is locked.
820 */
821 void udp_flush_pending_frames(struct sock *sk)
822 {
823 struct udp_sock *up = udp_sk(sk);
824
825 if (up->pending) {
826 up->len = 0;
827 WRITE_ONCE(up->pending, 0);
828 ip_flush_pending_frames(sk);
829 }
830 }
831 EXPORT_SYMBOL(udp_flush_pending_frames);
832
833 /**
834 * udp4_hwcsum - handle outgoing HW checksumming
835 * @skb: sk_buff containing the filled-in UDP header
836 * (checksum field must be zeroed out)
837 * @src: source IP address
838 * @dst: destination IP address
839 */
840 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
841 {
842 struct udphdr *uh = udp_hdr(skb);
843 int offset = skb_transport_offset(skb);
844 int len = skb->len - offset;
845 int hlen = len;
846 __wsum csum = 0;
847
848 if (!skb_has_frag_list(skb)) {
849 /*
850 * Only one fragment on the socket.
851 */
852 skb->csum_start = skb_transport_header(skb) - skb->head;
853 skb->csum_offset = offsetof(struct udphdr, check);
854 uh->check = ~csum_tcpudp_magic(src, dst, len,
855 IPPROTO_UDP, 0);
856 } else {
857 struct sk_buff *frags;
858
859 /*
860 * HW-checksum won't work as there are two or more
861 * fragments on the socket so that all csums of sk_buffs
862 * should be together
863 */
864 skb_walk_frags(skb, frags) {
865 csum = csum_add(csum, frags->csum);
866 hlen -= frags->len;
867 }
868
869 csum = skb_checksum(skb, offset, hlen, csum);
870 skb->ip_summed = CHECKSUM_NONE;
871
872 uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
873 if (uh->check == 0)
874 uh->check = CSUM_MANGLED_0;
875 }
876 }
877 EXPORT_SYMBOL_GPL(udp4_hwcsum);
878
879 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended
880 * for the simple case like when setting the checksum for a UDP tunnel.
881 */
882 void udp_set_csum(bool nocheck, struct sk_buff *skb,
883 __be32 saddr, __be32 daddr, int len)
884 {
885 struct udphdr *uh = udp_hdr(skb);
886
887 if (nocheck) {
888 uh->check = 0;
889 } else if (skb_is_gso(skb)) {
890 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
891 } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
892 uh->check = 0;
893 uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
894 if (uh->check == 0)
895 uh->check = CSUM_MANGLED_0;
896 } else {
897 skb->ip_summed = CHECKSUM_PARTIAL;
898 skb->csum_start = skb_transport_header(skb) - skb->head;
899 skb->csum_offset = offsetof(struct udphdr, check);
900 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
901 }
902 }
903 EXPORT_SYMBOL(udp_set_csum);
904
905 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
906 struct inet_cork *cork)
907 {
908 struct sock *sk = skb->sk;
909 struct inet_sock *inet = inet_sk(sk);
910 struct udphdr *uh;
911 int err;
912 int is_udplite = IS_UDPLITE(sk);
913 int offset = skb_transport_offset(skb);
914 int len = skb->len - offset;
915 int datalen = len - sizeof(*uh);
916 __wsum csum = 0;
917
918 /*
919 * Create a UDP header
920 */
921 uh = udp_hdr(skb);
922 uh->source = inet->inet_sport;
923 uh->dest = fl4->fl4_dport;
924 uh->len = htons(len);
925 uh->check = 0;
926
927 if (cork->gso_size) {
928 const int hlen = skb_network_header_len(skb) +
929 sizeof(struct udphdr);
930
931 if (hlen + cork->gso_size > cork->fragsize) {
932 kfree_skb(skb);
933 return -EINVAL;
934 }
935 if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
936 kfree_skb(skb);
937 return -EINVAL;
938 }
939 if (sk->sk_no_check_tx) {
940 kfree_skb(skb);
941 return -EINVAL;
942 }
943 if (is_udplite || dst_xfrm(skb_dst(skb))) {
944 kfree_skb(skb);
945 return -EIO;
946 }
947
948 if (datalen > cork->gso_size) {
949 skb_shinfo(skb)->gso_size = cork->gso_size;
950 skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
951 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen,
952 cork->gso_size);
953 }
954 goto csum_partial;
955 }
956
957 if (is_udplite) /* UDP-Lite */
958 csum = udplite_csum(skb);
959
960 else if (sk->sk_no_check_tx) { /* UDP csum off */
961
962 skb->ip_summed = CHECKSUM_NONE;
963 goto send;
964
965 } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
966 csum_partial:
967
968 udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
969 goto send;
970
971 } else
972 csum = udp_csum(skb);
973
974 /* add protocol-dependent pseudo-header */
975 uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
976 sk->sk_protocol, csum);
977 if (uh->check == 0)
978 uh->check = CSUM_MANGLED_0;
979
980 send:
981 err = ip_send_skb(sock_net(sk), skb);
982 if (err) {
983 if (err == -ENOBUFS &&
984 !inet_test_bit(RECVERR, sk)) {
985 UDP_INC_STATS(sock_net(sk),
986 UDP_MIB_SNDBUFERRORS, is_udplite);
987 err = 0;
988 }
989 } else
990 UDP_INC_STATS(sock_net(sk),
991 UDP_MIB_OUTDATAGRAMS, is_udplite);
992 return err;
993 }
994
995 /*
996 * Push out all pending data as one UDP datagram. Socket is locked.
997 */
998 int udp_push_pending_frames(struct sock *sk)
999 {
1000 struct udp_sock *up = udp_sk(sk);
1001 struct inet_sock *inet = inet_sk(sk);
1002 struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
1003 struct sk_buff *skb;
1004 int err = 0;
1005
1006 skb = ip_finish_skb(sk, fl4);
1007 if (!skb)
1008 goto out;
1009
1010 err = udp_send_skb(skb, fl4, &inet->cork.base);
1011
1012 out:
1013 up->len = 0;
1014 WRITE_ONCE(up->pending, 0);
1015 return err;
1016 }
1017 EXPORT_SYMBOL(udp_push_pending_frames);
1018
1019 static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
1020 {
1021 switch (cmsg->cmsg_type) {
1022 case UDP_SEGMENT:
1023 if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
1024 return -EINVAL;
1025 *gso_size = *(__u16 *)CMSG_DATA(cmsg);
1026 return 0;
1027 default:
1028 return -EINVAL;
1029 }
1030 }
1031
1032 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
1033 {
1034 struct cmsghdr *cmsg;
1035 bool need_ip = false;
1036 int err;
1037
1038 for_each_cmsghdr(cmsg, msg) {
1039 if (!CMSG_OK(msg, cmsg))
1040 return -EINVAL;
1041
1042 if (cmsg->cmsg_level != SOL_UDP) {
1043 need_ip = true;
1044 continue;
1045 }
1046
1047 err = __udp_cmsg_send(cmsg, gso_size);
1048 if (err)
1049 return err;
1050 }
1051
1052 return need_ip;
1053 }
1054 EXPORT_SYMBOL_GPL(udp_cmsg_send);
1055
1056 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1057 {
1058 struct inet_sock *inet = inet_sk(sk);
1059 struct udp_sock *up = udp_sk(sk);
1060 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
1061 struct flowi4 fl4_stack;
1062 struct flowi4 *fl4;
1063 int ulen = len;
1064 struct ipcm_cookie ipc;
1065 struct rtable *rt = NULL;
1066 int free = 0;
1067 int connected = 0;
1068 __be32 daddr, faddr, saddr;
1069 u8 tos, scope;
1070 __be16 dport;
1071 int err, is_udplite = IS_UDPLITE(sk);
1072 int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
1073 int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1074 struct sk_buff *skb;
1075 struct ip_options_data opt_copy;
1076 int uc_index;
1077
1078 if (len > 0xFFFF)
1079 return -EMSGSIZE;
1080
1081 /*
1082 * Check the flags.
1083 */
1084
1085 if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
1086 return -EOPNOTSUPP;
1087
1088 getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
1089
1090 fl4 = &inet->cork.fl.u.ip4;
1091 if (READ_ONCE(up->pending)) {
1092 /*
1093 * There are pending frames.
1094 * The socket lock must be held while it's corked.
1095 */
1096 lock_sock(sk);
1097 if (likely(up->pending)) {
1098 if (unlikely(up->pending != AF_INET)) {
1099 release_sock(sk);
1100 return -EINVAL;
1101 }
1102 goto do_append_data;
1103 }
1104 release_sock(sk);
1105 }
1106 ulen += sizeof(struct udphdr);
1107
1108 /*
1109 * Get and verify the address.
1110 */
1111 if (usin) {
1112 if (msg->msg_namelen < sizeof(*usin))
1113 return -EINVAL;
1114 if (usin->sin_family != AF_INET) {
1115 if (usin->sin_family != AF_UNSPEC)
1116 return -EAFNOSUPPORT;
1117 }
1118
1119 daddr = usin->sin_addr.s_addr;
1120 dport = usin->sin_port;
1121 if (dport == 0)
1122 return -EINVAL;
1123 } else {
1124 if (sk->sk_state != TCP_ESTABLISHED)
1125 return -EDESTADDRREQ;
1126 daddr = inet->inet_daddr;
1127 dport = inet->inet_dport;
1128 /* Open fast path for connected socket.
1129 Route will not be used, if at least one option is set.
1130 */
1131 connected = 1;
1132 }
1133
1134 ipcm_init_sk(&ipc, inet);
1135 ipc.gso_size = READ_ONCE(up->gso_size);
1136
1137 if (msg->msg_controllen) {
1138 err = udp_cmsg_send(sk, msg, &ipc.gso_size);
1139 if (err > 0) {
1140 err = ip_cmsg_send(sk, msg, &ipc,
1141 sk->sk_family == AF_INET6);
1142 connected = 0;
1143 }
1144 if (unlikely(err < 0)) {
1145 kfree(ipc.opt);
1146 return err;
1147 }
1148 if (ipc.opt)
1149 free = 1;
1150 }
1151 if (!ipc.opt) {
1152 struct ip_options_rcu *inet_opt;
1153
1154 rcu_read_lock();
1155 inet_opt = rcu_dereference(inet->inet_opt);
1156 if (inet_opt) {
1157 memcpy(&opt_copy, inet_opt,
1158 sizeof(*inet_opt) + inet_opt->opt.optlen);
1159 ipc.opt = &opt_copy.opt;
1160 }
1161 rcu_read_unlock();
1162 }
1163
1164 if (cgroup_bpf_enabled(CGROUP_UDP4_SENDMSG) && !connected) {
1165 err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
1166 (struct sockaddr *)usin,
1167 &msg->msg_namelen,
1168 &ipc.addr);
1169 if (err)
1170 goto out_free;
1171 if (usin) {
1172 if (usin->sin_port == 0) {
1173 /* BPF program set invalid port. Reject it. */
1174 err = -EINVAL;
1175 goto out_free;
1176 }
1177 daddr = usin->sin_addr.s_addr;
1178 dport = usin->sin_port;
1179 }
1180 }
1181
1182 saddr = ipc.addr;
1183 ipc.addr = faddr = daddr;
1184
1185 if (ipc.opt && ipc.opt->opt.srr) {
1186 if (!daddr) {
1187 err = -EINVAL;
1188 goto out_free;
1189 }
1190 faddr = ipc.opt->opt.faddr;
1191 connected = 0;
1192 }
1193 tos = get_rttos(&ipc, inet);
1194 scope = ip_sendmsg_scope(inet, &ipc, msg);
1195 if (scope == RT_SCOPE_LINK)
1196 connected = 0;
1197
1198 uc_index = READ_ONCE(inet->uc_index);
1199 if (ipv4_is_multicast(daddr)) {
1200 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
1201 ipc.oif = READ_ONCE(inet->mc_index);
1202 if (!saddr)
1203 saddr = READ_ONCE(inet->mc_addr);
1204 connected = 0;
1205 } else if (!ipc.oif) {
1206 ipc.oif = uc_index;
1207 } else if (ipv4_is_lbcast(daddr) && uc_index) {
1208 /* oif is set, packet is to local broadcast and
1209 * uc_index is set. oif is most likely set
1210 * by sk_bound_dev_if. If uc_index != oif check if the
1211 * oif is an L3 master and uc_index is an L3 slave.
1212 * If so, we want to allow the send using the uc_index.
1213 */
1214 if (ipc.oif != uc_index &&
1215 ipc.oif == l3mdev_master_ifindex_by_index(sock_net(sk),
1216 uc_index)) {
1217 ipc.oif = uc_index;
1218 }
1219 }
1220
1221 if (connected)
1222 rt = dst_rtable(sk_dst_check(sk, 0));
1223
1224 if (!rt) {
1225 struct net *net = sock_net(sk);
1226 __u8 flow_flags = inet_sk_flowi_flags(sk);
1227
1228 fl4 = &fl4_stack;
1229
1230 flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark, tos, scope,
1231 sk->sk_protocol, flow_flags, faddr, saddr,
1232 dport, inet->inet_sport, sk->sk_uid);
1233
1234 security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
1235 rt = ip_route_output_flow(net, fl4, sk);
1236 if (IS_ERR(rt)) {
1237 err = PTR_ERR(rt);
1238 rt = NULL;
1239 if (err == -ENETUNREACH)
1240 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1241 goto out;
1242 }
1243
1244 err = -EACCES;
1245 if ((rt->rt_flags & RTCF_BROADCAST) &&
1246 !sock_flag(sk, SOCK_BROADCAST))
1247 goto out;
1248 if (connected)
1249 sk_dst_set(sk, dst_clone(&rt->dst));
1250 }
1251
1252 if (msg->msg_flags&MSG_CONFIRM)
1253 goto do_confirm;
1254 back_from_confirm:
1255
1256 saddr = fl4->saddr;
1257 if (!ipc.addr)
1258 daddr = ipc.addr = fl4->daddr;
1259
1260 /* Lockless fast path for the non-corking case. */
1261 if (!corkreq) {
1262 struct inet_cork cork;
1263
1264 skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
1265 sizeof(struct udphdr), &ipc, &rt,
1266 &cork, msg->msg_flags);
1267 err = PTR_ERR(skb);
1268 if (!IS_ERR_OR_NULL(skb))
1269 err = udp_send_skb(skb, fl4, &cork);
1270 goto out;
1271 }
1272
1273 lock_sock(sk);
1274 if (unlikely(up->pending)) {
1275 /* The socket is already corked while preparing it. */
1276 /* ... which is an evident application bug. --ANK */
1277 release_sock(sk);
1278
1279 net_dbg_ratelimited("socket already corked\n");
1280 err = -EINVAL;
1281 goto out;
1282 }
1283 /*
1284 * Now cork the socket to pend data.
1285 */
1286 fl4 = &inet->cork.fl.u.ip4;
1287 fl4->daddr = daddr;
1288 fl4->saddr = saddr;
1289 fl4->fl4_dport = dport;
1290 fl4->fl4_sport = inet->inet_sport;
1291 WRITE_ONCE(up->pending, AF_INET);
1292
1293 do_append_data:
1294 up->len += ulen;
1295 err = ip_append_data(sk, fl4, getfrag, msg, ulen,
1296 sizeof(struct udphdr), &ipc, &rt,
1297 corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1298 if (err)
1299 udp_flush_pending_frames(sk);
1300 else if (!corkreq)
1301 err = udp_push_pending_frames(sk);
1302 else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1303 WRITE_ONCE(up->pending, 0);
1304 release_sock(sk);
1305
1306 out:
1307 ip_rt_put(rt);
1308 out_free:
1309 if (free)
1310 kfree(ipc.opt);
1311 if (!err)
1312 return len;
1313 /*
1314 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting
1315 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1316 * we don't have a good statistic (IpOutDiscards but it can be too many
1317 * things). We could add another new stat but at least for now that
1318 * seems like overkill.
1319 */
1320 if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1321 UDP_INC_STATS(sock_net(sk),
1322 UDP_MIB_SNDBUFERRORS, is_udplite);
1323 }
1324 return err;
1325
1326 do_confirm:
1327 if (msg->msg_flags & MSG_PROBE)
1328 dst_confirm_neigh(&rt->dst, &fl4->daddr);
1329 if (!(msg->msg_flags&MSG_PROBE) || len)
1330 goto back_from_confirm;
1331 err = 0;
1332 goto out;
1333 }
1334 EXPORT_SYMBOL(udp_sendmsg);
1335
1336 void udp_splice_eof(struct socket *sock)
1337 {
1338 struct sock *sk = sock->sk;
1339 struct udp_sock *up = udp_sk(sk);
1340
1341 if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk))
1342 return;
1343
1344 lock_sock(sk);
1345 if (up->pending && !udp_test_bit(CORK, sk))
1346 udp_push_pending_frames(sk);
1347 release_sock(sk);
1348 }
1349 EXPORT_SYMBOL_GPL(udp_splice_eof);
1350
1351 #define UDP_SKB_IS_STATELESS 0x80000000
1352
1353 /* all head states (dst, sk, nf conntrack) except skb extensions are
1354 * cleared by udp_rcv().
1355 *
1356 * We need to preserve secpath, if present, to eventually process
1357 * IP_CMSG_PASSSEC at recvmsg() time.
1358 *
1359 * Other extensions can be cleared.
1360 */
1361 static bool udp_try_make_stateless(struct sk_buff *skb)
1362 {
1363 if (!skb_has_extensions(skb))
1364 return true;
1365
1366 if (!secpath_exists(skb)) {
1367 skb_ext_reset(skb);
1368 return true;
1369 }
1370
1371 return false;
1372 }
1373
1374 static void udp_set_dev_scratch(struct sk_buff *skb)
1375 {
1376 struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
1377
1378 BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
1379 scratch->_tsize_state = skb->truesize;
1380 #if BITS_PER_LONG == 64
1381 scratch->len = skb->len;
1382 scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
1383 scratch->is_linear = !skb_is_nonlinear(skb);
1384 #endif
1385 if (udp_try_make_stateless(skb))
1386 scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
1387 }
1388
1389 static void udp_skb_csum_unnecessary_set(struct sk_buff *skb)
1390 {
1391 /* We come here after udp_lib_checksum_complete() returned 0.
1392 * This means that __skb_checksum_complete() might have
1393 * set skb->csum_valid to 1.
1394 * On 64bit platforms, we can set csum_unnecessary
1395 * to true, but only if the skb is not shared.
1396 */
1397 #if BITS_PER_LONG == 64
1398 if (!skb_shared(skb))
1399 udp_skb_scratch(skb)->csum_unnecessary = true;
1400 #endif
1401 }
1402
1403 static int udp_skb_truesize(struct sk_buff *skb)
1404 {
1405 return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
1406 }
1407
1408 static bool udp_skb_has_head_state(struct sk_buff *skb)
1409 {
1410 return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
1411 }
1412
1413 /* fully reclaim rmem/fwd memory allocated for skb */
1414 static void udp_rmem_release(struct sock *sk, int size, int partial,
1415 bool rx_queue_lock_held)
1416 {
1417 struct udp_sock *up = udp_sk(sk);
1418 struct sk_buff_head *sk_queue;
1419 int amt;
1420
1421 if (likely(partial)) {
1422 up->forward_deficit += size;
1423 size = up->forward_deficit;
1424 if (size < READ_ONCE(up->forward_threshold) &&
1425 !skb_queue_empty(&up->reader_queue))
1426 return;
1427 } else {
1428 size += up->forward_deficit;
1429 }
1430 up->forward_deficit = 0;
1431
1432 /* acquire the sk_receive_queue for fwd allocated memory scheduling,
1433 * if the called don't held it already
1434 */
1435 sk_queue = &sk->sk_receive_queue;
1436 if (!rx_queue_lock_held)
1437 spin_lock(&sk_queue->lock);
1438
1439
1440 sk_forward_alloc_add(sk, size);
1441 amt = (sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - 1);
1442 sk_forward_alloc_add(sk, -amt);
1443
1444 if (amt)
1445 __sk_mem_reduce_allocated(sk, amt >> PAGE_SHIFT);
1446
1447 atomic_sub(size, &sk->sk_rmem_alloc);
1448
1449 /* this can save us from acquiring the rx queue lock on next receive */
1450 skb_queue_splice_tail_init(sk_queue, &up->reader_queue);
1451
1452 if (!rx_queue_lock_held)
1453 spin_unlock(&sk_queue->lock);
1454 }
1455
1456 /* Note: called with reader_queue.lock held.
1457 * Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
1458 * This avoids a cache line miss while receive_queue lock is held.
1459 * Look at __udp_enqueue_schedule_skb() to find where this copy is done.
1460 */
1461 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
1462 {
1463 prefetch(&skb->data);
1464 udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
1465 }
1466 EXPORT_SYMBOL(udp_skb_destructor);
1467
1468 /* as above, but the caller held the rx queue lock, too */
1469 static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
1470 {
1471 prefetch(&skb->data);
1472 udp_rmem_release(sk, udp_skb_truesize(skb), 1, true);
1473 }
1474
1475 /* Idea of busylocks is to let producers grab an extra spinlock
1476 * to relieve pressure on the receive_queue spinlock shared by consumer.
1477 * Under flood, this means that only one producer can be in line
1478 * trying to acquire the receive_queue spinlock.
1479 * These busylock can be allocated on a per cpu manner, instead of a
1480 * per socket one (that would consume a cache line per socket)
1481 */
1482 static int udp_busylocks_log __read_mostly;
1483 static spinlock_t *udp_busylocks __read_mostly;
1484
1485 static spinlock_t *busylock_acquire(void *ptr)
1486 {
1487 spinlock_t *busy;
1488
1489 busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log);
1490 spin_lock(busy);
1491 return busy;
1492 }
1493
1494 static void busylock_release(spinlock_t *busy)
1495 {
1496 if (busy)
1497 spin_unlock(busy);
1498 }
1499
1500 static int udp_rmem_schedule(struct sock *sk, int size)
1501 {
1502 int delta;
1503
1504 delta = size - sk->sk_forward_alloc;
1505 if (delta > 0 && !__sk_mem_schedule(sk, delta, SK_MEM_RECV))
1506 return -ENOBUFS;
1507
1508 return 0;
1509 }
1510
1511 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
1512 {
1513 struct sk_buff_head *list = &sk->sk_receive_queue;
1514 int rmem, err = -ENOMEM;
1515 spinlock_t *busy = NULL;
1516 bool becomes_readable;
1517 int size, rcvbuf;
1518
1519 /* Immediately drop when the receive queue is full.
1520 * Always allow at least one packet.
1521 */
1522 rmem = atomic_read(&sk->sk_rmem_alloc);
1523 rcvbuf = READ_ONCE(sk->sk_rcvbuf);
1524 if (rmem > rcvbuf)
1525 goto drop;
1526
1527 /* Under mem pressure, it might be helpful to help udp_recvmsg()
1528 * having linear skbs :
1529 * - Reduce memory overhead and thus increase receive queue capacity
1530 * - Less cache line misses at copyout() time
1531 * - Less work at consume_skb() (less alien page frag freeing)
1532 */
1533 if (rmem > (rcvbuf >> 1)) {
1534 skb_condense(skb);
1535
1536 busy = busylock_acquire(sk);
1537 }
1538 size = skb->truesize;
1539 udp_set_dev_scratch(skb);
1540
1541 atomic_add(size, &sk->sk_rmem_alloc);
1542
1543 spin_lock(&list->lock);
1544 err = udp_rmem_schedule(sk, size);
1545 if (err) {
1546 spin_unlock(&list->lock);
1547 goto uncharge_drop;
1548 }
1549
1550 sk_forward_alloc_add(sk, -size);
1551
1552 /* no need to setup a destructor, we will explicitly release the
1553 * forward allocated memory on dequeue
1554 */
1555 sock_skb_set_dropcount(sk, skb);
1556
1557 becomes_readable = skb_queue_empty(list);
1558 __skb_queue_tail(list, skb);
1559 spin_unlock(&list->lock);
1560
1561 if (!sock_flag(sk, SOCK_DEAD)) {
1562 if (becomes_readable ||
1563 sk->sk_data_ready != sock_def_readable ||
1564 READ_ONCE(sk->sk_peek_off) >= 0)
1565 INDIRECT_CALL_1(sk->sk_data_ready,
1566 sock_def_readable, sk);
1567 else
1568 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN);
1569 }
1570 busylock_release(busy);
1571 return 0;
1572
1573 uncharge_drop:
1574 atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
1575
1576 drop:
1577 atomic_inc(&sk->sk_drops);
1578 busylock_release(busy);
1579 return err;
1580 }
1581 EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
1582
1583 void udp_destruct_common(struct sock *sk)
1584 {
1585 /* reclaim completely the forward allocated memory */
1586 struct udp_sock *up = udp_sk(sk);
1587 unsigned int total = 0;
1588 struct sk_buff *skb;
1589
1590 skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue);
1591 while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) {
1592 total += skb->truesize;
1593 kfree_skb(skb);
1594 }
1595 udp_rmem_release(sk, total, 0, true);
1596 }
1597 EXPORT_SYMBOL_GPL(udp_destruct_common);
1598
1599 static void udp_destruct_sock(struct sock *sk)
1600 {
1601 udp_destruct_common(sk);
1602 inet_sock_destruct(sk);
1603 }
1604
1605 int udp_init_sock(struct sock *sk)
1606 {
1607 udp_lib_init_sock(sk);
1608 sk->sk_destruct = udp_destruct_sock;
1609 set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
1610 return 0;
1611 }
1612
1613 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
1614 {
1615 if (unlikely(READ_ONCE(udp_sk(sk)->peeking_with_offset)))
1616 sk_peek_offset_bwd(sk, len);
1617
1618 if (!skb_unref(skb))
1619 return;
1620
1621 /* In the more common cases we cleared the head states previously,
1622 * see __udp_queue_rcv_skb().
1623 */
1624 if (unlikely(udp_skb_has_head_state(skb)))
1625 skb_release_head_state(skb);
1626 __consume_stateless_skb(skb);
1627 }
1628 EXPORT_SYMBOL_GPL(skb_consume_udp);
1629
1630 static struct sk_buff *__first_packet_length(struct sock *sk,
1631 struct sk_buff_head *rcvq,
1632 int *total)
1633 {
1634 struct sk_buff *skb;
1635
1636 while ((skb = skb_peek(rcvq)) != NULL) {
1637 if (udp_lib_checksum_complete(skb)) {
1638 __UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
1639 IS_UDPLITE(sk));
1640 __UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
1641 IS_UDPLITE(sk));
1642 atomic_inc(&sk->sk_drops);
1643 __skb_unlink(skb, rcvq);
1644 *total += skb->truesize;
1645 kfree_skb(skb);
1646 } else {
1647 udp_skb_csum_unnecessary_set(skb);
1648 break;
1649 }
1650 }
1651 return skb;
1652 }
1653
1654 /**
1655 * first_packet_length - return length of first packet in receive queue
1656 * @sk: socket
1657 *
1658 * Drops all bad checksum frames, until a valid one is found.
1659 * Returns the length of found skb, or -1 if none is found.
1660 */
1661 static int first_packet_length(struct sock *sk)
1662 {
1663 struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
1664 struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1665 struct sk_buff *skb;
1666 int total = 0;
1667 int res;
1668
1669 spin_lock_bh(&rcvq->lock);
1670 skb = __first_packet_length(sk, rcvq, &total);
1671 if (!skb && !skb_queue_empty_lockless(sk_queue)) {
1672 spin_lock(&sk_queue->lock);
1673 skb_queue_splice_tail_init(sk_queue, rcvq);
1674 spin_unlock(&sk_queue->lock);
1675
1676 skb = __first_packet_length(sk, rcvq, &total);
1677 }
1678 res = skb ? skb->len : -1;
1679 if (total)
1680 udp_rmem_release(sk, total, 1, false);
1681 spin_unlock_bh(&rcvq->lock);
1682 return res;
1683 }
1684
1685 /*
1686 * IOCTL requests applicable to the UDP protocol
1687 */
1688
1689 int udp_ioctl(struct sock *sk, int cmd, int *karg)
1690 {
1691 switch (cmd) {
1692 case SIOCOUTQ:
1693 {
1694 *karg = sk_wmem_alloc_get(sk);
1695 return 0;
1696 }
1697
1698 case SIOCINQ:
1699 {
1700 *karg = max_t(int, 0, first_packet_length(sk));
1701 return 0;
1702 }
1703
1704 default:
1705 return -ENOIOCTLCMD;
1706 }
1707
1708 return 0;
1709 }
1710 EXPORT_SYMBOL(udp_ioctl);
1711
1712 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
1713 int *off, int *err)
1714 {
1715 struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1716 struct sk_buff_head *queue;
1717 struct sk_buff *last;
1718 long timeo;
1719 int error;
1720
1721 queue = &udp_sk(sk)->reader_queue;
1722 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1723 do {
1724 struct sk_buff *skb;
1725
1726 error = sock_error(sk);
1727 if (error)
1728 break;
1729
1730 error = -EAGAIN;
1731 do {
1732 spin_lock_bh(&queue->lock);
1733 skb = __skb_try_recv_from_queue(sk, queue, flags, off,
1734 err, &last);
1735 if (skb) {
1736 if (!(flags & MSG_PEEK))
1737 udp_skb_destructor(sk, skb);
1738 spin_unlock_bh(&queue->lock);
1739 return skb;
1740 }
1741
1742 if (skb_queue_empty_lockless(sk_queue)) {
1743 spin_unlock_bh(&queue->lock);
1744 goto busy_check;
1745 }
1746
1747 /* refill the reader queue and walk it again
1748 * keep both queues locked to avoid re-acquiring
1749 * the sk_receive_queue lock if fwd memory scheduling
1750 * is needed.
1751 */
1752 spin_lock(&sk_queue->lock);
1753 skb_queue_splice_tail_init(sk_queue, queue);
1754
1755 skb = __skb_try_recv_from_queue(sk, queue, flags, off,
1756 err, &last);
1757 if (skb && !(flags & MSG_PEEK))
1758 udp_skb_dtor_locked(sk, skb);
1759 spin_unlock(&sk_queue->lock);
1760 spin_unlock_bh(&queue->lock);
1761 if (skb)
1762 return skb;
1763
1764 busy_check:
1765 if (!sk_can_busy_loop(sk))
1766 break;
1767
1768 sk_busy_loop(sk, flags & MSG_DONTWAIT);
1769 } while (!skb_queue_empty_lockless(sk_queue));
1770
1771 /* sk_queue is empty, reader_queue may contain peeked packets */
1772 } while (timeo &&
1773 !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue,
1774 &error, &timeo,
1775 (struct sk_buff *)sk_queue));
1776
1777 *err = error;
1778 return NULL;
1779 }
1780 EXPORT_SYMBOL(__skb_recv_udp);
1781
1782 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
1783 {
1784 struct sk_buff *skb;
1785 int err;
1786
1787 try_again:
1788 skb = skb_recv_udp(sk, MSG_DONTWAIT, &err);
1789 if (!skb)
1790 return err;
1791
1792 if (udp_lib_checksum_complete(skb)) {
1793 int is_udplite = IS_UDPLITE(sk);
1794 struct net *net = sock_net(sk);
1795
1796 __UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, is_udplite);
1797 __UDP_INC_STATS(net, UDP_MIB_INERRORS, is_udplite);
1798 atomic_inc(&sk->sk_drops);
1799 kfree_skb(skb);
1800 goto try_again;
1801 }
1802
1803 WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
1804 return recv_actor(sk, skb);
1805 }
1806 EXPORT_SYMBOL(udp_read_skb);
1807
1808 /*
1809 * This should be easy, if there is something there we
1810 * return it, otherwise we block.
1811 */
1812
1813 int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
1814 int *addr_len)
1815 {
1816 struct inet_sock *inet = inet_sk(sk);
1817 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1818 struct sk_buff *skb;
1819 unsigned int ulen, copied;
1820 int off, err, peeking = flags & MSG_PEEK;
1821 int is_udplite = IS_UDPLITE(sk);
1822 bool checksum_valid = false;
1823
1824 if (flags & MSG_ERRQUEUE)
1825 return ip_recv_error(sk, msg, len, addr_len);
1826
1827 try_again:
1828 off = sk_peek_offset(sk, flags);
1829 skb = __skb_recv_udp(sk, flags, &off, &err);
1830 if (!skb)
1831 return err;
1832 if (ccs_socket_post_recvmsg_permission(sk, skb, flags))
1833 return -EAGAIN; /* Hope less harmful than -EPERM. */
1834
1835 ulen = udp_skb_len(skb);
1836 copied = len;
1837 if (copied > ulen - off)
1838 copied = ulen - off;
1839 else if (copied < ulen)
1840 msg->msg_flags |= MSG_TRUNC;
1841
1842 /*
1843 * If checksum is needed at all, try to do it while copying the
1844 * data. If the data is truncated, or if we only want a partial
1845 * coverage checksum (UDP-Lite), do it before the copy.
1846 */
1847
1848 if (copied < ulen || peeking ||
1849 (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
1850 checksum_valid = udp_skb_csum_unnecessary(skb) ||
1851 !__udp_lib_checksum_complete(skb);
1852 if (!checksum_valid)
1853 goto csum_copy_err;
1854 }
1855
1856 if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
1857 if (udp_skb_is_linear(skb))
1858 err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
1859 else
1860 err = skb_copy_datagram_msg(skb, off, msg, copied);
1861 } else {
1862 err = skb_copy_and_csum_datagram_msg(skb, off, msg);
1863
1864 if (err == -EINVAL)
1865 goto csum_copy_err;
1866 }
1867
1868 if (unlikely(err)) {
1869 if (!peeking) {
1870 atomic_inc(&sk->sk_drops);
1871 UDP_INC_STATS(sock_net(sk),
1872 UDP_MIB_INERRORS, is_udplite);
1873 }
1874 kfree_skb(skb);
1875 return err;
1876 }
1877
1878 if (!peeking)
1879 UDP_INC_STATS(sock_net(sk),
1880 UDP_MIB_INDATAGRAMS, is_udplite);
1881
1882 sock_recv_cmsgs(msg, sk, skb);
1883
1884 /* Copy the address. */
1885 if (sin) {
1886 sin->sin_family = AF_INET;
1887 sin->sin_port = udp_hdr(skb)->source;
1888 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1889 memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1890 *addr_len = sizeof(*sin);
1891
1892 BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
1893 (struct sockaddr *)sin,
1894 addr_len);
1895 }
1896
1897 if (udp_test_bit(GRO_ENABLED, sk))
1898 udp_cmsg_recv(msg, sk, skb);
1899
1900 if (inet_cmsg_flags(inet))
1901 ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off);
1902
1903 err = copied;
1904 if (flags & MSG_TRUNC)
1905 err = ulen;
1906
1907 skb_consume_udp(sk, skb, peeking ? -err : err);
1908 return err;
1909
1910 csum_copy_err:
1911 if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
1912 udp_skb_destructor)) {
1913 UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1914 UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1915 }
1916 kfree_skb(skb);
1917
1918 /* starting over for a new packet, but check if we need to yield */
1919 cond_resched();
1920 msg->msg_flags &= ~MSG_TRUNC;
1921 goto try_again;
1922 }
1923
1924 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
1925 {
1926 /* This check is replicated from __ip4_datagram_connect() and
1927 * intended to prevent BPF program called below from accessing bytes
1928 * that are out of the bound specified by user in addr_len.
1929 */
1930 if (addr_len < sizeof(struct sockaddr_in))
1931 return -EINVAL;
1932
1933 return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
1934 }
1935 EXPORT_SYMBOL(udp_pre_connect);
1936
1937 int __udp_disconnect(struct sock *sk, int flags)
1938 {
1939 struct inet_sock *inet = inet_sk(sk);
1940 /*
1941 * 1003.1g - break association.
1942 */
1943
1944 sk->sk_state = TCP_CLOSE;
1945 inet->inet_daddr = 0;
1946 inet->inet_dport = 0;
1947 sock_rps_reset_rxhash(sk);
1948 sk->sk_bound_dev_if = 0;
1949 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) {
1950 inet_reset_saddr(sk);
1951 if (sk->sk_prot->rehash &&
1952 (sk->sk_userlocks & SOCK_BINDPORT_LOCK))
1953 sk->sk_prot->rehash(sk);
1954 }
1955
1956 if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1957 sk->sk_prot->unhash(sk);
1958 inet->inet_sport = 0;
1959 }
1960 sk_dst_reset(sk);
1961 return 0;
1962 }
1963 EXPORT_SYMBOL(__udp_disconnect);
1964
1965 int udp_disconnect(struct sock *sk, int flags)
1966 {
1967 lock_sock(sk);
1968 __udp_disconnect(sk, flags);
1969 release_sock(sk);
1970 return 0;
1971 }
1972 EXPORT_SYMBOL(udp_disconnect);
1973
1974 void udp_lib_unhash(struct sock *sk)
1975 {
1976 if (sk_hashed(sk)) {
1977 struct udp_table *udptable = udp_get_table_prot(sk);
1978 struct udp_hslot *hslot, *hslot2;
1979
1980 hslot = udp_hashslot(udptable, sock_net(sk),
1981 udp_sk(sk)->udp_port_hash);
1982 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1983
1984 spin_lock_bh(&hslot->lock);
1985 if (rcu_access_pointer(sk->sk_reuseport_cb))
1986 reuseport_detach_sock(sk);
1987 if (sk_del_node_init_rcu(sk)) {
1988 hslot->count--;
1989 inet_sk(sk)->inet_num = 0;
1990 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1991
1992 spin_lock(&hslot2->lock);
1993 hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1994 hslot2->count--;
1995 spin_unlock(&hslot2->lock);
1996 }
1997 spin_unlock_bh(&hslot->lock);
1998 }
1999 }
2000 EXPORT_SYMBOL(udp_lib_unhash);
2001
2002 /*
2003 * inet_rcv_saddr was changed, we must rehash secondary hash
2004 */
2005 void udp_lib_rehash(struct sock *sk, u16 newhash)
2006 {
2007 if (sk_hashed(sk)) {
2008 struct udp_table *udptable = udp_get_table_prot(sk);
2009 struct udp_hslot *hslot, *hslot2, *nhslot2;
2010
2011 hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
2012 nhslot2 = udp_hashslot2(udptable, newhash);
2013 udp_sk(sk)->udp_portaddr_hash = newhash;
2014
2015 if (hslot2 != nhslot2 ||
2016 rcu_access_pointer(sk->sk_reuseport_cb)) {
2017 hslot = udp_hashslot(udptable, sock_net(sk),
2018 udp_sk(sk)->udp_port_hash);
2019 /* we must lock primary chain too */
2020 spin_lock_bh(&hslot->lock);
2021 if (rcu_access_pointer(sk->sk_reuseport_cb))
2022 reuseport_detach_sock(sk);
2023
2024 if (hslot2 != nhslot2) {
2025 spin_lock(&hslot2->lock);
2026 hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
2027 hslot2->count--;
2028 spin_unlock(&hslot2->lock);
2029
2030 spin_lock(&nhslot2->lock);
2031 hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
2032 &nhslot2->head);
2033 nhslot2->count++;
2034 spin_unlock(&nhslot2->lock);
2035 }
2036
2037 spin_unlock_bh(&hslot->lock);
2038 }
2039 }
2040 }
2041 EXPORT_SYMBOL(udp_lib_rehash);
2042
2043 void udp_v4_rehash(struct sock *sk)
2044 {
2045 u16 new_hash = ipv4_portaddr_hash(sock_net(sk),
2046 inet_sk(sk)->inet_rcv_saddr,
2047 inet_sk(sk)->inet_num);
2048 udp_lib_rehash(sk, new_hash);
2049 }
2050
2051 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
2052 {
2053 int rc;
2054
2055 if (inet_sk(sk)->inet_daddr) {
2056 sock_rps_save_rxhash(sk, skb);
2057 sk_mark_napi_id(sk, skb);
2058 sk_incoming_cpu_update(sk);
2059 } else {
2060 sk_mark_napi_id_once(sk, skb);
2061 }
2062
2063 rc = __udp_enqueue_schedule_skb(sk, skb);
2064 if (rc < 0) {
2065 int is_udplite = IS_UDPLITE(sk);
2066 int drop_reason;
2067
2068 /* Note that an ENOMEM error is charged twice */
2069 if (rc == -ENOMEM) {
2070 UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
2071 is_udplite);
2072 drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
2073 } else {
2074 UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS,
2075 is_udplite);
2076 drop_reason = SKB_DROP_REASON_PROTO_MEM;
2077 }
2078 UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2079 trace_udp_fail_queue_rcv_skb(rc, sk, skb);
2080 sk_skb_reason_drop(sk, skb, drop_reason);
2081 return -1;
2082 }
2083
2084 return 0;
2085 }
2086
2087 /* returns:
2088 * -1: error
2089 * 0: success
2090 * >0: "udp encap" protocol resubmission
2091 *
2092 * Note that in the success and error cases, the skb is assumed to
2093 * have either been requeued or freed.
2094 */
2095 static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
2096 {
2097 int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2098 struct udp_sock *up = udp_sk(sk);
2099 int is_udplite = IS_UDPLITE(sk);
2100
2101 /*
2102 * Charge it to the socket, dropping if the queue is full.
2103 */
2104 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
2105 drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2106 goto drop;
2107 }
2108 nf_reset_ct(skb);
2109
2110 if (static_branch_unlikely(&udp_encap_needed_key) &&
2111 READ_ONCE(up->encap_type)) {
2112 int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
2113
2114 /*
2115 * This is an encapsulation socket so pass the skb to
2116 * the socket's udp_encap_rcv() hook. Otherwise, just
2117 * fall through and pass this up the UDP socket.
2118 * up->encap_rcv() returns the following value:
2119 * =0 if skb was successfully passed to the encap
2120 * handler or was discarded by it.
2121 * >0 if skb should be passed on to UDP.
2122 * <0 if skb should be resubmitted as proto -N
2123 */
2124
2125 /* if we're overly short, let UDP handle it */
2126 encap_rcv = READ_ONCE(up->encap_rcv);
2127 if (encap_rcv) {
2128 int ret;
2129
2130 /* Verify checksum before giving to encap */
2131 if (udp_lib_checksum_complete(skb))
2132 goto csum_error;
2133
2134 ret = encap_rcv(sk, skb);
2135 if (ret <= 0) {
2136 __UDP_INC_STATS(sock_net(sk),
2137 UDP_MIB_INDATAGRAMS,
2138 is_udplite);
2139 return -ret;
2140 }
2141 }
2142
2143 /* FALLTHROUGH -- it's a UDP Packet */
2144 }
2145
2146 /*
2147 * UDP-Lite specific tests, ignored on UDP sockets
2148 */
2149 if (udp_test_bit(UDPLITE_RECV_CC, sk) && UDP_SKB_CB(skb)->partial_cov) {
2150 u16 pcrlen = READ_ONCE(up->pcrlen);
2151
2152 /*
2153 * MIB statistics other than incrementing the error count are
2154 * disabled for the following two types of errors: these depend
2155 * on the application settings, not on the functioning of the
2156 * protocol stack as such.
2157 *
2158 * RFC 3828 here recommends (sec 3.3): "There should also be a
2159 * way ... to ... at least let the receiving application block
2160 * delivery of packets with coverage values less than a value
2161 * provided by the application."
2162 */
2163 if (pcrlen == 0) { /* full coverage was set */
2164 net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
2165 UDP_SKB_CB(skb)->cscov, skb->len);
2166 goto drop;
2167 }
2168 /* The next case involves violating the min. coverage requested
2169 * by the receiver. This is subtle: if receiver wants x and x is
2170 * greater than the buffersize/MTU then receiver will complain
2171 * that it wants x while sender emits packets of smaller size y.
2172 * Therefore the above ...()->partial_cov statement is essential.
2173 */
2174 if (UDP_SKB_CB(skb)->cscov < pcrlen) {
2175 net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
2176 UDP_SKB_CB(skb)->cscov, pcrlen);
2177 goto drop;
2178 }
2179 }
2180
2181 prefetch(&sk->sk_rmem_alloc);
2182 if (rcu_access_pointer(sk->sk_filter) &&
2183 udp_lib_checksum_complete(skb))
2184 goto csum_error;
2185
2186 if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) {
2187 drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
2188 goto drop;
2189 }
2190
2191 udp_csum_pull_header(skb);
2192
2193 ipv4_pktinfo_prepare(sk, skb, true);
2194 return __udp_queue_rcv_skb(sk, skb);
2195
2196 csum_error:
2197 drop_reason = SKB_DROP_REASON_UDP_CSUM;
2198 __UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
2199 drop:
2200 __UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2201 atomic_inc(&sk->sk_drops);
2202 sk_skb_reason_drop(sk, skb, drop_reason);
2203 return -1;
2204 }
2205
2206 static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
2207 {
2208 struct sk_buff *next, *segs;
2209 int ret;
2210
2211 if (likely(!udp_unexpected_gso(sk, skb)))
2212 return udp_queue_rcv_one_skb(sk, skb);
2213
2214 BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_GSO_CB_OFFSET);
2215 __skb_push(skb, -skb_mac_offset(skb));
2216 segs = udp_rcv_segment(sk, skb, true);
2217 skb_list_walk_safe(segs, skb, next) {
2218 __skb_pull(skb, skb_transport_offset(skb));
2219
2220 udp_post_segment_fix_csum(skb);
2221 ret = udp_queue_rcv_one_skb(sk, skb);
2222 if (ret > 0)
2223 ip_protocol_deliver_rcu(dev_net(skb->dev), skb, ret);
2224 }
2225 return 0;
2226 }
2227
2228 /* For TCP sockets, sk_rx_dst is protected by socket lock
2229 * For UDP, we use xchg() to guard against concurrent changes.
2230 */
2231 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
2232 {
2233 struct dst_entry *old;
2234
2235 if (dst_hold_safe(dst)) {
2236 old = unrcu_pointer(xchg(&sk->sk_rx_dst, RCU_INITIALIZER(dst)));
2237 dst_release(old);
2238 return old != dst;
2239 }
2240 return false;
2241 }
2242 EXPORT_SYMBOL(udp_sk_rx_dst_set);
2243
2244 /*
2245 * Multicasts and broadcasts go to each listener.
2246 *
2247 * Note: called only from the BH handler context.
2248 */
2249 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
2250 struct udphdr *uh,
2251 __be32 saddr, __be32 daddr,
2252 struct udp_table *udptable,
2253 int proto)
2254 {
2255 struct sock *sk, *first = NULL;
2256 unsigned short hnum = ntohs(uh->dest);
2257 struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
2258 unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
2259 unsigned int offset = offsetof(typeof(*sk), sk_node);
2260 int dif = skb->dev->ifindex;
2261 int sdif = inet_sdif(skb);
2262 struct hlist_node *node;
2263 struct sk_buff *nskb;
2264
2265 if (use_hash2) {
2266 hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
2267 udptable->mask;
2268 hash2 = ipv4_portaddr_hash(net, daddr, hnum) & udptable->mask;
2269 start_lookup:
2270 hslot = &udptable->hash2[hash2];
2271 offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
2272 }
2273
2274 sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
2275 if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
2276 uh->source, saddr, dif, sdif, hnum))
2277 continue;
2278
2279 if (!first) {
2280 first = sk;
2281 continue;
2282 }
2283 nskb = skb_clone(skb, GFP_ATOMIC);
2284
2285 if (unlikely(!nskb)) {
2286 atomic_inc(&sk->sk_drops);
2287 __UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
2288 IS_UDPLITE(sk));
2289 __UDP_INC_STATS(net, UDP_MIB_INERRORS,
2290 IS_UDPLITE(sk));
2291 continue;
2292 }
2293 if (udp_queue_rcv_skb(sk, nskb) > 0)
2294 consume_skb(nskb);
2295 }
2296
2297 /* Also lookup *:port if we are using hash2 and haven't done so yet. */
2298 if (use_hash2 && hash2 != hash2_any) {
2299 hash2 = hash2_any;
2300 goto start_lookup;
2301 }
2302
2303 if (first) {
2304 if (udp_queue_rcv_skb(first, skb) > 0)
2305 consume_skb(skb);
2306 } else {
2307 kfree_skb(skb);
2308 __UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
2309 proto == IPPROTO_UDPLITE);
2310 }
2311 return 0;
2312 }
2313
2314 /* Initialize UDP checksum. If exited with zero value (success),
2315 * CHECKSUM_UNNECESSARY means, that no more checks are required.
2316 * Otherwise, csum completion requires checksumming packet body,
2317 * including udp header and folding it to skb->csum.
2318 */
2319 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
2320 int proto)
2321 {
2322 int err;
2323
2324 UDP_SKB_CB(skb)->partial_cov = 0;
2325 UDP_SKB_CB(skb)->cscov = skb->len;
2326
2327 if (proto == IPPROTO_UDPLITE) {
2328 err = udplite_checksum_init(skb, uh);
2329 if (err)
2330 return err;
2331
2332 if (UDP_SKB_CB(skb)->partial_cov) {
2333 skb->csum = inet_compute_pseudo(skb, proto);
2334 return 0;
2335 }
2336 }
2337
2338 /* Note, we are only interested in != 0 or == 0, thus the
2339 * force to int.
2340 */
2341 err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
2342 inet_compute_pseudo);
2343 if (err)
2344 return err;
2345
2346 if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
2347 /* If SW calculated the value, we know it's bad */
2348 if (skb->csum_complete_sw)
2349 return 1;
2350
2351 /* HW says the value is bad. Let's validate that.
2352 * skb->csum is no longer the full packet checksum,
2353 * so don't treat it as such.
2354 */
2355 skb_checksum_complete_unset(skb);
2356 }
2357
2358 return 0;
2359 }
2360
2361 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
2362 * return code conversion for ip layer consumption
2363 */
2364 static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
2365 struct udphdr *uh)
2366 {
2367 int ret;
2368
2369 if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
2370 skb_checksum_try_convert(skb, IPPROTO_UDP, inet_compute_pseudo);
2371
2372 ret = udp_queue_rcv_skb(sk, skb);
2373
2374 /* a return value > 0 means to resubmit the input, but
2375 * it wants the return to be -protocol, or 0
2376 */
2377 if (ret > 0)
2378 return -ret;
2379 return 0;
2380 }
2381
2382 /*
2383 * All we need to do is get the socket, and then do a checksum.
2384 */
2385
2386 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
2387 int proto)
2388 {
2389 struct sock *sk = NULL;
2390 struct udphdr *uh;
2391 unsigned short ulen;
2392 struct rtable *rt = skb_rtable(skb);
2393 __be32 saddr, daddr;
2394 struct net *net = dev_net(skb->dev);
2395 bool refcounted;
2396 int drop_reason;
2397
2398 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2399
2400 /*
2401 * Validate the packet.
2402 */
2403 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
2404 goto drop; /* No space for header. */
2405
2406 uh = udp_hdr(skb);
2407 ulen = ntohs(uh->len);
2408 saddr = ip_hdr(skb)->saddr;
2409 daddr = ip_hdr(skb)->daddr;
2410
2411 if (ulen > skb->len)
2412 goto short_packet;
2413
2414 if (proto == IPPROTO_UDP) {
2415 /* UDP validates ulen. */
2416 if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
2417 goto short_packet;
2418 uh = udp_hdr(skb);
2419 }
2420
2421 if (udp4_csum_init(skb, uh, proto))
2422 goto csum_error;
2423
2424 sk = inet_steal_sock(net, skb, sizeof(struct udphdr), saddr, uh->source, daddr, uh->dest,
2425 &refcounted, udp_ehashfn);
2426 if (IS_ERR(sk))
2427 goto no_sk;
2428
2429 if (sk) {
2430 struct dst_entry *dst = skb_dst(skb);
2431 int ret;
2432
2433 if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
2434 udp_sk_rx_dst_set(sk, dst);
2435
2436 ret = udp_unicast_rcv_skb(sk, skb, uh);
2437 if (refcounted)
2438 sock_put(sk);
2439 return ret;
2440 }
2441
2442 if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
2443 return __udp4_lib_mcast_deliver(net, skb, uh,
2444 saddr, daddr, udptable, proto);
2445
2446 sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
2447 if (sk)
2448 return udp_unicast_rcv_skb(sk, skb, uh);
2449 no_sk:
2450 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2451 goto drop;
2452 nf_reset_ct(skb);
2453
2454 /* No socket. Drop packet silently, if checksum is wrong */
2455 if (udp_lib_checksum_complete(skb))
2456 goto csum_error;
2457
2458 drop_reason = SKB_DROP_REASON_NO_SOCKET;
2459 __UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
2460 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
2461
2462 /*
2463 * Hmm. We got an UDP packet to a port to which we
2464 * don't wanna listen. Ignore it.
2465 */
2466 sk_skb_reason_drop(sk, skb, drop_reason);
2467 return 0;
2468
2469 short_packet:
2470 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2471 net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
2472 proto == IPPROTO_UDPLITE ? "Lite" : "",
2473 &saddr, ntohs(uh->source),
2474 ulen, skb->len,
2475 &daddr, ntohs(uh->dest));
2476 goto drop;
2477
2478 csum_error:
2479 /*
2480 * RFC1122: OK. Discards the bad packet silently (as far as
2481 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
2482 */
2483 drop_reason = SKB_DROP_REASON_UDP_CSUM;
2484 net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
2485 proto == IPPROTO_UDPLITE ? "Lite" : "",
2486 &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
2487 ulen);
2488 __UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
2489 drop:
2490 __UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
2491 sk_skb_reason_drop(sk, skb, drop_reason);
2492 return 0;
2493 }
2494
2495 /* We can only early demux multicast if there is a single matching socket.
2496 * If more than one socket found returns NULL
2497 */
2498 static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
2499 __be16 loc_port, __be32 loc_addr,
2500 __be16 rmt_port, __be32 rmt_addr,
2501 int dif, int sdif)
2502 {
2503 struct udp_table *udptable = net->ipv4.udp_table;
2504 unsigned short hnum = ntohs(loc_port);
2505 struct sock *sk, *result;
2506 struct udp_hslot *hslot;
2507 unsigned int slot;
2508
2509 slot = udp_hashfn(net, hnum, udptable->mask);
2510 hslot = &udptable->hash[slot];
2511
2512 /* Do not bother scanning a too big list */
2513 if (hslot->count > 10)
2514 return NULL;
2515
2516 result = NULL;
2517 sk_for_each_rcu(sk, &hslot->head) {
2518 if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
2519 rmt_port, rmt_addr, dif, sdif, hnum)) {
2520 if (result)
2521 return NULL;
2522 result = sk;
2523 }
2524 }
2525
2526 return result;
2527 }
2528
2529 /* For unicast we should only early demux connected sockets or we can
2530 * break forwarding setups. The chains here can be long so only check
2531 * if the first socket is an exact match and if not move on.
2532 */
2533 static struct sock *__udp4_lib_demux_lookup(struct net *net,
2534 __be16 loc_port, __be32 loc_addr,
2535 __be16 rmt_port, __be32 rmt_addr,
2536 int dif, int sdif)
2537 {
2538 struct udp_table *udptable = net->ipv4.udp_table;
2539 INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
2540 unsigned short hnum = ntohs(loc_port);
2541 unsigned int hash2, slot2;
2542 struct udp_hslot *hslot2;
2543 __portpair ports;
2544 struct sock *sk;
2545
2546 hash2 = ipv4_portaddr_hash(net, loc_addr, hnum);
2547 slot2 = hash2 & udptable->mask;
2548 hslot2 = &udptable->hash2[slot2];
2549 ports = INET_COMBINED_PORTS(rmt_port, hnum);
2550
2551 udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
2552 if (inet_match(net, sk, acookie, ports, dif, sdif))
2553 return sk;
2554 /* Only check first socket in chain */
2555 break;
2556 }
2557 return NULL;
2558 }
2559
2560 int udp_v4_early_demux(struct sk_buff *skb)
2561 {
2562 struct net *net = dev_net(skb->dev);
2563 struct in_device *in_dev = NULL;
2564 const struct iphdr *iph;
2565 const struct udphdr *uh;
2566 struct sock *sk = NULL;
2567 struct dst_entry *dst;
2568 int dif = skb->dev->ifindex;
2569 int sdif = inet_sdif(skb);
2570 int ours;
2571
2572 /* validate the packet */
2573 if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
2574 return 0;
2575
2576 iph = ip_hdr(skb);
2577 uh = udp_hdr(skb);
2578
2579 if (skb->pkt_type == PACKET_MULTICAST) {
2580 in_dev = __in_dev_get_rcu(skb->dev);
2581
2582 if (!in_dev)
2583 return 0;
2584
2585 ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
2586 iph->protocol);
2587 if (!ours)
2588 return 0;
2589
2590 sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
2591 uh->source, iph->saddr,
2592 dif, sdif);
2593 } else if (skb->pkt_type == PACKET_HOST) {
2594 sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
2595 uh->source, iph->saddr, dif, sdif);
2596 }
2597
2598 if (!sk)
2599 return 0;
2600
2601 skb->sk = sk;
2602 DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk));
2603 skb->destructor = sock_pfree;
2604 dst = rcu_dereference(sk->sk_rx_dst);
2605
2606 if (dst)
2607 dst = dst_check(dst, 0);
2608 if (dst) {
2609 u32 itag = 0;
2610
2611 /* set noref for now.
2612 * any place which wants to hold dst has to call
2613 * dst_hold_safe()
2614 */
2615 skb_dst_set_noref(skb, dst);
2616
2617 /* for unconnected multicast sockets we need to validate
2618 * the source on each packet
2619 */
2620 if (!inet_sk(sk)->inet_daddr && in_dev)
2621 return ip_mc_validate_source(skb, iph->daddr,
2622 iph->saddr,
2623 iph->tos & IPTOS_RT_MASK,
2624 skb->dev, in_dev, &itag);
2625 }
2626 return 0;
2627 }
2628
2629 int udp_rcv(struct sk_buff *skb)
2630 {
2631 return __udp4_lib_rcv(skb, dev_net(skb->dev)->ipv4.udp_table, IPPROTO_UDP);
2632 }
2633
2634 void udp_destroy_sock(struct sock *sk)
2635 {
2636 struct udp_sock *up = udp_sk(sk);
2637 bool slow = lock_sock_fast(sk);
2638
2639 /* protects from races with udp_abort() */
2640 sock_set_flag(sk, SOCK_DEAD);
2641 udp_flush_pending_frames(sk);
2642 unlock_sock_fast(sk, slow);
2643 if (static_branch_unlikely(&udp_encap_needed_key)) {
2644 if (up->encap_type) {
2645 void (*encap_destroy)(struct sock *sk);
2646 encap_destroy = READ_ONCE(up->encap_destroy);
2647 if (encap_destroy)
2648 encap_destroy(sk);
2649 }
2650 if (udp_test_bit(ENCAP_ENABLED, sk))
2651 static_branch_dec(&udp_encap_needed_key);
2652 }
2653 }
2654
2655 static void set_xfrm_gro_udp_encap_rcv(__u16 encap_type, unsigned short family,
2656 struct sock *sk)
2657 {
2658 #ifdef CONFIG_XFRM
2659 if (udp_test_bit(GRO_ENABLED, sk) && encap_type == UDP_ENCAP_ESPINUDP) {
2660 if (family == AF_INET)
2661 WRITE_ONCE(udp_sk(sk)->gro_receive, xfrm4_gro_udp_encap_rcv);
2662 else if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6)
2663 WRITE_ONCE(udp_sk(sk)->gro_receive, ipv6_stub->xfrm6_gro_udp_encap_rcv);
2664 }
2665 #endif
2666 }
2667
2668 /*
2669 * Socket option code for UDP
2670 */
2671 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
2672 sockptr_t optval, unsigned int optlen,
2673 int (*push_pending_frames)(struct sock *))
2674 {
2675 struct udp_sock *up = udp_sk(sk);
2676 int val, valbool;
2677 int err = 0;
2678 int is_udplite = IS_UDPLITE(sk);
2679
2680 if (level == SOL_SOCKET) {
2681 err = sk_setsockopt(sk, level, optname, optval, optlen);
2682
2683 if (optname == SO_RCVBUF || optname == SO_RCVBUFFORCE) {
2684 sockopt_lock_sock(sk);
2685 /* paired with READ_ONCE in udp_rmem_release() */
2686 WRITE_ONCE(up->forward_threshold, sk->sk_rcvbuf >> 2);
2687 sockopt_release_sock(sk);
2688 }
2689 return err;
2690 }
2691
2692 if (optlen < sizeof(int))
2693 return -EINVAL;
2694
2695 if (copy_from_sockptr(&val, optval, sizeof(val)))
2696 return -EFAULT;
2697
2698 valbool = val ? 1 : 0;
2699
2700 switch (optname) {
2701 case UDP_CORK:
2702 if (val != 0) {
2703 udp_set_bit(CORK, sk);
2704 } else {
2705 udp_clear_bit(CORK, sk);
2706 lock_sock(sk);
2707 push_pending_frames(sk);
2708 release_sock(sk);
2709 }
2710 break;
2711
2712 case UDP_ENCAP:
2713 switch (val) {
2714 case 0:
2715 #ifdef CONFIG_XFRM
2716 case UDP_ENCAP_ESPINUDP:
2717 set_xfrm_gro_udp_encap_rcv(val, sk->sk_family, sk);
2718 #if IS_ENABLED(CONFIG_IPV6)
2719 if (sk->sk_family == AF_INET6)
2720 WRITE_ONCE(up->encap_rcv,
2721 ipv6_stub->xfrm6_udp_encap_rcv);
2722 else
2723 #endif
2724 WRITE_ONCE(up->encap_rcv,
2725 xfrm4_udp_encap_rcv);
2726 #endif
2727 fallthrough;
2728 case UDP_ENCAP_L2TPINUDP:
2729 WRITE_ONCE(up->encap_type, val);
2730 udp_tunnel_encap_enable(sk);
2731 break;
2732 default:
2733 err = -ENOPROTOOPT;
2734 break;
2735 }
2736 break;
2737
2738 case UDP_NO_CHECK6_TX:
2739 udp_set_no_check6_tx(sk, valbool);
2740 break;
2741
2742 case UDP_NO_CHECK6_RX:
2743 udp_set_no_check6_rx(sk, valbool);
2744 break;
2745
2746 case UDP_SEGMENT:
2747 if (val < 0 || val > USHRT_MAX)
2748 return -EINVAL;
2749 WRITE_ONCE(up->gso_size, val);
2750 break;
2751
2752 case UDP_GRO:
2753
2754 /* when enabling GRO, accept the related GSO packet type */
2755 if (valbool)
2756 udp_tunnel_encap_enable(sk);
2757 udp_assign_bit(GRO_ENABLED, sk, valbool);
2758 udp_assign_bit(ACCEPT_L4, sk, valbool);
2759 set_xfrm_gro_udp_encap_rcv(up->encap_type, sk->sk_family, sk);
2760 break;
2761
2762 /*
2763 * UDP-Lite's partial checksum coverage (RFC 3828).
2764 */
2765 /* The sender sets actual checksum coverage length via this option.
2766 * The case coverage > packet length is handled by send module. */
2767 case UDPLITE_SEND_CSCOV:
2768 if (!is_udplite) /* Disable the option on UDP sockets */
2769 return -ENOPROTOOPT;
2770 if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2771 val = 8;
2772 else if (val > USHRT_MAX)
2773 val = USHRT_MAX;
2774 WRITE_ONCE(up->pcslen, val);
2775 udp_set_bit(UDPLITE_SEND_CC, sk);
2776 break;
2777
2778 /* The receiver specifies a minimum checksum coverage value. To make
2779 * sense, this should be set to at least 8 (as done below). If zero is
2780 * used, this again means full checksum coverage. */
2781 case UDPLITE_RECV_CSCOV:
2782 if (!is_udplite) /* Disable the option on UDP sockets */
2783 return -ENOPROTOOPT;
2784 if (val != 0 && val < 8) /* Avoid silly minimal values. */
2785 val = 8;
2786 else if (val > USHRT_MAX)
2787 val = USHRT_MAX;
2788 WRITE_ONCE(up->pcrlen, val);
2789 udp_set_bit(UDPLITE_RECV_CC, sk);
2790 break;
2791
2792 default:
2793 err = -ENOPROTOOPT;
2794 break;
2795 }
2796
2797 return err;
2798 }
2799 EXPORT_SYMBOL(udp_lib_setsockopt);
2800
2801 int udp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
2802 unsigned int optlen)
2803 {
2804 if (level == SOL_UDP || level == SOL_UDPLITE || level == SOL_SOCKET)
2805 return udp_lib_setsockopt(sk, level, optname,
2806 optval, optlen,
2807 udp_push_pending_frames);
2808 return ip_setsockopt(sk, level, optname, optval, optlen);
2809 }
2810
2811 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2812 char __user *optval, int __user *optlen)
2813 {
2814 struct udp_sock *up = udp_sk(sk);
2815 int val, len;
2816
2817 if (get_user(len, optlen))
2818 return -EFAULT;
2819
2820 if (len < 0)
2821 return -EINVAL;
2822
2823 len = min_t(unsigned int, len, sizeof(int));
2824
2825 switch (optname) {
2826 case UDP_CORK:
2827 val = udp_test_bit(CORK, sk);
2828 break;
2829
2830 case UDP_ENCAP:
2831 val = READ_ONCE(up->encap_type);
2832 break;
2833
2834 case UDP_NO_CHECK6_TX:
2835 val = udp_get_no_check6_tx(sk);
2836 break;
2837
2838 case UDP_NO_CHECK6_RX:
2839 val = udp_get_no_check6_rx(sk);
2840 break;
2841
2842 case UDP_SEGMENT:
2843 val = READ_ONCE(up->gso_size);
2844 break;
2845
2846 case UDP_GRO:
2847 val = udp_test_bit(GRO_ENABLED, sk);
2848 break;
2849
2850 /* The following two cannot be changed on UDP sockets, the return is
2851 * always 0 (which corresponds to the full checksum coverage of UDP). */
2852 case UDPLITE_SEND_CSCOV:
2853 val = READ_ONCE(up->pcslen);
2854 break;
2855
2856 case UDPLITE_RECV_CSCOV:
2857 val = READ_ONCE(up->pcrlen);
2858 break;
2859
2860 default:
2861 return -ENOPROTOOPT;
2862 }
2863
2864 if (put_user(len, optlen))
2865 return -EFAULT;
2866 if (copy_to_user(optval, &val, len))
2867 return -EFAULT;
2868 return 0;
2869 }
2870 EXPORT_SYMBOL(udp_lib_getsockopt);
2871
2872 int udp_getsockopt(struct sock *sk, int level, int optname,
2873 char __user *optval, int __user *optlen)
2874 {
2875 if (level == SOL_UDP || level == SOL_UDPLITE)
2876 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2877 return ip_getsockopt(sk, level, optname, optval, optlen);
2878 }
2879
2880 /**
2881 * udp_poll - wait for a UDP event.
2882 * @file: - file struct
2883 * @sock: - socket
2884 * @wait: - poll table
2885 *
2886 * This is same as datagram poll, except for the special case of
2887 * blocking sockets. If application is using a blocking fd
2888 * and a packet with checksum error is in the queue;
2889 * then it could get return from select indicating data available
2890 * but then block when reading it. Add special case code
2891 * to work around these arguably broken applications.
2892 */
2893 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2894 {
2895 __poll_t mask = datagram_poll(file, sock, wait);
2896 struct sock *sk = sock->sk;
2897
2898 if (!skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
2899 mask |= EPOLLIN | EPOLLRDNORM;
2900
2901 /* Check for false positives due to checksum errors */
2902 if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2903 !(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
2904 mask &= ~(EPOLLIN | EPOLLRDNORM);
2905
2906 /* psock ingress_msg queue should not contain any bad checksum frames */
2907 if (sk_is_readable(sk))
2908 mask |= EPOLLIN | EPOLLRDNORM;
2909 return mask;
2910
2911 }
2912 EXPORT_SYMBOL(udp_poll);
2913
2914 int udp_abort(struct sock *sk, int err)
2915 {
2916 if (!has_current_bpf_ctx())
2917 lock_sock(sk);
2918
2919 /* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing
2920 * with close()
2921 */
2922 if (sock_flag(sk, SOCK_DEAD))
2923 goto out;
2924
2925 sk->sk_err = err;
2926 sk_error_report(sk);
2927 __udp_disconnect(sk, 0);
2928
2929 out:
2930 if (!has_current_bpf_ctx())
2931 release_sock(sk);
2932
2933 return 0;
2934 }
2935 EXPORT_SYMBOL_GPL(udp_abort);
2936
2937 struct proto udp_prot = {
2938 .name = "UDP",
2939 .owner = THIS_MODULE,
2940 .close = udp_lib_close,
2941 .pre_connect = udp_pre_connect,
2942 .connect = ip4_datagram_connect,
2943 .disconnect = udp_disconnect,
2944 .ioctl = udp_ioctl,
2945 .init = udp_init_sock,
2946 .destroy = udp_destroy_sock,
2947 .setsockopt = udp_setsockopt,
2948 .getsockopt = udp_getsockopt,
2949 .sendmsg = udp_sendmsg,
2950 .recvmsg = udp_recvmsg,
2951 .splice_eof = udp_splice_eof,
2952 .release_cb = ip4_datagram_release_cb,
2953 .hash = udp_lib_hash,
2954 .unhash = udp_lib_unhash,
2955 .rehash = udp_v4_rehash,
2956 .get_port = udp_v4_get_port,
2957 .put_port = udp_lib_unhash,
2958 #ifdef CONFIG_BPF_SYSCALL
2959 .psock_update_sk_prot = udp_bpf_update_proto,
2960 #endif
2961 .memory_allocated = &udp_memory_allocated,
2962 .per_cpu_fw_alloc = &udp_memory_per_cpu_fw_alloc,
2963
2964 .sysctl_mem = sysctl_udp_mem,
2965 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
2966 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
2967 .obj_size = sizeof(struct udp_sock),
2968 .h.udp_table = NULL,
2969 .diag_destroy = udp_abort,
2970 };
2971 EXPORT_SYMBOL(udp_prot);
2972
2973 /* ------------------------------------------------------------------------ */
2974 #ifdef CONFIG_PROC_FS
2975
2976 static unsigned short seq_file_family(const struct seq_file *seq);
2977 static bool seq_sk_match(struct seq_file *seq, const struct sock *sk)
2978 {
2979 unsigned short family = seq_file_family(seq);
2980
2981 /* AF_UNSPEC is used as a match all */
2982 return ((family == AF_UNSPEC || family == sk->sk_family) &&
2983 net_eq(sock_net(sk), seq_file_net(seq)));
2984 }
2985
2986 #ifdef CONFIG_BPF_SYSCALL
2987 static const struct seq_operations bpf_iter_udp_seq_ops;
2988 #endif
2989 static struct udp_table *udp_get_table_seq(struct seq_file *seq,
2990 struct net *net)
2991 {
2992 const struct udp_seq_afinfo *afinfo;
2993
2994 #ifdef CONFIG_BPF_SYSCALL
2995 if (seq->op == &bpf_iter_udp_seq_ops)
2996 return net->ipv4.udp_table;
2997 #endif
2998
2999 afinfo = pde_data(file_inode(seq->file));
3000 return afinfo->udp_table ? : net->ipv4.udp_table;
3001 }
3002
3003 static struct sock *udp_get_first(struct seq_file *seq, int start)
3004 {
3005 struct udp_iter_state *state = seq->private;
3006 struct net *net = seq_file_net(seq);
3007 struct udp_table *udptable;
3008 struct sock *sk;
3009
3010 udptable = udp_get_table_seq(seq, net);
3011
3012 for (state->bucket = start; state->bucket <= udptable->mask;
3013 ++state->bucket) {
3014 struct udp_hslot *hslot = &udptable->hash[state->bucket];
3015
3016 if (hlist_empty(&hslot->head))
3017 continue;
3018
3019 spin_lock_bh(&hslot->lock);
3020 sk_for_each(sk, &hslot->head) {
3021 if (seq_sk_match(seq, sk))
3022 goto found;
3023 }
3024 spin_unlock_bh(&hslot->lock);
3025 }
3026 sk = NULL;
3027 found:
3028 return sk;
3029 }
3030
3031 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
3032 {
3033 struct udp_iter_state *state = seq->private;
3034 struct net *net = seq_file_net(seq);
3035 struct udp_table *udptable;
3036
3037 do {
3038 sk = sk_next(sk);
3039 } while (sk && !seq_sk_match(seq, sk));
3040
3041 if (!sk) {
3042 udptable = udp_get_table_seq(seq, net);
3043
3044 if (state->bucket <= udptable->mask)
3045 spin_unlock_bh(&udptable->hash[state->bucket].lock);
3046
3047 return udp_get_first(seq, state->bucket + 1);
3048 }
3049 return sk;
3050 }
3051
3052 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
3053 {
3054 struct sock *sk = udp_get_first(seq, 0);
3055
3056 if (sk)
3057 while (pos && (sk = udp_get_next(seq, sk)) != NULL)
3058 --pos;
3059 return pos ? NULL : sk;
3060 }
3061
3062 void *udp_seq_start(struct seq_file *seq, loff_t *pos)
3063 {
3064 struct udp_iter_state *state = seq->private;
3065 state->bucket = MAX_UDP_PORTS;
3066
3067 return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
3068 }
3069 EXPORT_SYMBOL(udp_seq_start);
3070
3071 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3072 {
3073 struct sock *sk;
3074
3075 if (v == SEQ_START_TOKEN)
3076 sk = udp_get_idx(seq, 0);
3077 else
3078 sk = udp_get_next(seq, v);
3079
3080 ++*pos;
3081 return sk;
3082 }
3083 EXPORT_SYMBOL(udp_seq_next);
3084
3085 void udp_seq_stop(struct seq_file *seq, void *v)
3086 {
3087 struct udp_iter_state *state = seq->private;
3088 struct udp_table *udptable;
3089
3090 udptable = udp_get_table_seq(seq, seq_file_net(seq));
3091
3092 if (state->bucket <= udptable->mask)
3093 spin_unlock_bh(&udptable->hash[state->bucket].lock);
3094 }
3095 EXPORT_SYMBOL(udp_seq_stop);
3096
3097 /* ------------------------------------------------------------------------ */
3098 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
3099 int bucket)
3100 {
3101 struct inet_sock *inet = inet_sk(sp);
3102 __be32 dest = inet->inet_daddr;
3103 __be32 src = inet->inet_rcv_saddr;
3104 __u16 destp = ntohs(inet->inet_dport);
3105 __u16 srcp = ntohs(inet->inet_sport);
3106
3107 seq_printf(f, "%5d: %08X:%04X %08X:%04X"
3108 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
3109 bucket, src, srcp, dest, destp, sp->sk_state,
3110 sk_wmem_alloc_get(sp),
3111 udp_rqueue_get(sp),
3112 0, 0L, 0,
3113 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
3114 0, sock_i_ino(sp),
3115 refcount_read(&sp->sk_refcnt), sp,
3116 atomic_read(&sp->sk_drops));
3117 }
3118
3119 int udp4_seq_show(struct seq_file *seq, void *v)
3120 {
3121 seq_setwidth(seq, 127);
3122 if (v == SEQ_START_TOKEN)
3123 seq_puts(seq, " sl local_address rem_address st tx_queue "
3124 "rx_queue tr tm->when retrnsmt uid timeout "
3125 "inode ref pointer drops");
3126 else {
3127 struct udp_iter_state *state = seq->private;
3128
3129 udp4_format_sock(v, seq, state->bucket);
3130 }
3131 seq_pad(seq, '\n');
3132 return 0;
3133 }
3134
3135 #ifdef CONFIG_BPF_SYSCALL
3136 struct bpf_iter__udp {
3137 __bpf_md_ptr(struct bpf_iter_meta *, meta);
3138 __bpf_md_ptr(struct udp_sock *, udp_sk);
3139 uid_t uid __aligned(8);
3140 int bucket __aligned(8);
3141 };
3142
3143 struct bpf_udp_iter_state {
3144 struct udp_iter_state state;
3145 unsigned int cur_sk;
3146 unsigned int end_sk;
3147 unsigned int max_sk;
3148 int offset;
3149 struct sock **batch;
3150 bool st_bucket_done;
3151 };
3152
3153 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
3154 unsigned int new_batch_sz);
3155 static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
3156 {
3157 struct bpf_udp_iter_state *iter = seq->private;
3158 struct udp_iter_state *state = &iter->state;
3159 struct net *net = seq_file_net(seq);
3160 int resume_bucket, resume_offset;
3161 struct udp_table *udptable;
3162 unsigned int batch_sks = 0;
3163 bool resized = false;
3164 struct sock *sk;
3165
3166 resume_bucket = state->bucket;
3167 resume_offset = iter->offset;
3168
3169 /* The current batch is done, so advance the bucket. */
3170 if (iter->st_bucket_done)
3171 state->bucket++;
3172
3173 udptable = udp_get_table_seq(seq, net);
3174
3175 again:
3176 /* New batch for the next bucket.
3177 * Iterate over the hash table to find a bucket with sockets matching
3178 * the iterator attributes, and return the first matching socket from
3179 * the bucket. The remaining matched sockets from the bucket are batched
3180 * before releasing the bucket lock. This allows BPF programs that are
3181 * called in seq_show to acquire the bucket lock if needed.
3182 */
3183 iter->cur_sk = 0;
3184 iter->end_sk = 0;
3185 iter->st_bucket_done = false;
3186 batch_sks = 0;
3187
3188 for (; state->bucket <= udptable->mask; state->bucket++) {
3189 struct udp_hslot *hslot2 = &udptable->hash2[state->bucket];
3190
3191 if (hlist_empty(&hslot2->head))
3192 continue;
3193
3194 iter->offset = 0;
3195 spin_lock_bh(&hslot2->lock);
3196 udp_portaddr_for_each_entry(sk, &hslot2->head) {
3197 if (seq_sk_match(seq, sk)) {
3198 /* Resume from the last iterated socket at the
3199 * offset in the bucket before iterator was stopped.
3200 */
3201 if (state->bucket == resume_bucket &&
3202 iter->offset < resume_offset) {
3203 ++iter->offset;
3204 continue;
3205 }
3206 if (iter->end_sk < iter->max_sk) {
3207 sock_hold(sk);
3208 iter->batch[iter->end_sk++] = sk;
3209 }
3210 batch_sks++;
3211 }
3212 }
3213 spin_unlock_bh(&hslot2->lock);
3214
3215 if (iter->end_sk)
3216 break;
3217 }
3218
3219 /* All done: no batch made. */
3220 if (!iter->end_sk)
3221 return NULL;
3222
3223 if (iter->end_sk == batch_sks) {
3224 /* Batching is done for the current bucket; return the first
3225 * socket to be iterated from the batch.
3226 */
3227 iter->st_bucket_done = true;
3228 goto done;
3229 }
3230 if (!resized && !bpf_iter_udp_realloc_batch(iter, batch_sks * 3 / 2)) {
3231 resized = true;
3232 /* After allocating a larger batch, retry one more time to grab
3233 * the whole bucket.
3234 */
3235 goto again;
3236 }
3237 done:
3238 return iter->batch[0];
3239 }
3240
3241 static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
3242 {
3243 struct bpf_udp_iter_state *iter = seq->private;
3244 struct sock *sk;
3245
3246 /* Whenever seq_next() is called, the iter->cur_sk is
3247 * done with seq_show(), so unref the iter->cur_sk.
3248 */
3249 if (iter->cur_sk < iter->end_sk) {
3250 sock_put(iter->batch[iter->cur_sk++]);
3251 ++iter->offset;
3252 }
3253
3254 /* After updating iter->cur_sk, check if there are more sockets
3255 * available in the current bucket batch.
3256 */
3257 if (iter->cur_sk < iter->end_sk)
3258 sk = iter->batch[iter->cur_sk];
3259 else
3260 /* Prepare a new batch. */
3261 sk = bpf_iter_udp_batch(seq);
3262
3263 ++*pos;
3264 return sk;
3265 }
3266
3267 static void *bpf_iter_udp_seq_start(struct seq_file *seq, loff_t *pos)
3268 {
3269 /* bpf iter does not support lseek, so it always
3270 * continue from where it was stop()-ped.
3271 */
3272 if (*pos)
3273 return bpf_iter_udp_batch(seq);
3274
3275 return SEQ_START_TOKEN;
3276 }
3277
3278 static int udp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta,
3279 struct udp_sock *udp_sk, uid_t uid, int bucket)
3280 {
3281 struct bpf_iter__udp ctx;
3282
3283 meta->seq_num--; /* skip SEQ_START_TOKEN */
3284 ctx.meta = meta;
3285 ctx.udp_sk = udp_sk;
3286 ctx.uid = uid;
3287 ctx.bucket = bucket;
3288 return bpf_iter_run_prog(prog, &ctx);
3289 }
3290
3291 static int bpf_iter_udp_seq_show(struct seq_file *seq, void *v)
3292 {
3293 struct udp_iter_state *state = seq->private;
3294 struct bpf_iter_meta meta;
3295 struct bpf_prog *prog;
3296 struct sock *sk = v;
3297 uid_t uid;
3298 int ret;
3299
3300 if (v == SEQ_START_TOKEN)
3301 return 0;
3302
3303 lock_sock(sk);
3304
3305 if (unlikely(sk_unhashed(sk))) {
3306 ret = SEQ_SKIP;
3307 goto unlock;
3308 }
3309
3310 uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk));
3311 meta.seq = seq;
3312 prog = bpf_iter_get_info(&meta, false);
3313 ret = udp_prog_seq_show(prog, &meta, v, uid, state->bucket);
3314
3315 unlock:
3316 release_sock(sk);
3317 return ret;
3318 }
3319
3320 static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter)
3321 {
3322 while (iter->cur_sk < iter->end_sk)
3323 sock_put(iter->batch[iter->cur_sk++]);
3324 }
3325
3326 static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
3327 {
3328 struct bpf_udp_iter_state *iter = seq->private;
3329 struct bpf_iter_meta meta;
3330 struct bpf_prog *prog;
3331
3332 if (!v) {
3333 meta.seq = seq;
3334 prog = bpf_iter_get_info(&meta, true);
3335 if (prog)
3336 (void)udp_prog_seq_show(prog, &meta, v, 0, 0);
3337 }
3338
3339 if (iter->cur_sk < iter->end_sk) {
3340 bpf_iter_udp_put_batch(iter);
3341 iter->st_bucket_done = false;
3342 }
3343 }
3344
3345 static const struct seq_operations bpf_iter_udp_seq_ops = {
3346 .start = bpf_iter_udp_seq_start,
3347 .next = bpf_iter_udp_seq_next,
3348 .stop = bpf_iter_udp_seq_stop,
3349 .show = bpf_iter_udp_seq_show,
3350 };
3351 #endif
3352
3353 static unsigned short seq_file_family(const struct seq_file *seq)
3354 {
3355 const struct udp_seq_afinfo *afinfo;
3356
3357 #ifdef CONFIG_BPF_SYSCALL
3358 /* BPF iterator: bpf programs to filter sockets. */
3359 if (seq->op == &bpf_iter_udp_seq_ops)
3360 return AF_UNSPEC;
3361 #endif
3362
3363 /* Proc fs iterator */
3364 afinfo = pde_data(file_inode(seq->file));
3365 return afinfo->family;
3366 }
3367
3368 const struct seq_operations udp_seq_ops = {
3369 .start = udp_seq_start,
3370 .next = udp_seq_next,
3371 .stop = udp_seq_stop,
3372 .show = udp4_seq_show,
3373 };
3374 EXPORT_SYMBOL(udp_seq_ops);
3375
3376 static struct udp_seq_afinfo udp4_seq_afinfo = {
3377 .family = AF_INET,
3378 .udp_table = NULL,
3379 };
3380
3381 static int __net_init udp4_proc_init_net(struct net *net)
3382 {
3383 if (!proc_create_net_data("udp", 0444, net->proc_net, &udp_seq_ops,
3384 sizeof(struct udp_iter_state), &udp4_seq_afinfo))
3385 return -ENOMEM;
3386 return 0;
3387 }
3388
3389 static void __net_exit udp4_proc_exit_net(struct net *net)
3390 {
3391 remove_proc_entry("udp", net->proc_net);
3392 }
3393
3394 static struct pernet_operations udp4_net_ops = {
3395 .init = udp4_proc_init_net,
3396 .exit = udp4_proc_exit_net,
3397 };
3398
3399 int __init udp4_proc_init(void)
3400 {
3401 return register_pernet_subsys(&udp4_net_ops);
3402 }
3403
3404 void udp4_proc_exit(void)
3405 {
3406 unregister_pernet_subsys(&udp4_net_ops);
3407 }
3408 #endif /* CONFIG_PROC_FS */
3409
3410 static __initdata unsigned long uhash_entries;
3411 static int __init set_uhash_entries(char *str)
3412 {
3413 ssize_t ret;
3414
3415 if (!str)
3416 return 0;
3417
3418 ret = kstrtoul(str, 0, &uhash_entries);
3419 if (ret)
3420 return 0;
3421
3422 if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
3423 uhash_entries = UDP_HTABLE_SIZE_MIN;
3424 return 1;
3425 }
3426 __setup("uhash_entries=", set_uhash_entries);
3427
3428 void __init udp_table_init(struct udp_table *table, const char *name)
3429 {
3430 unsigned int i;
3431
3432 table->hash = alloc_large_system_hash(name,
3433 2 * sizeof(struct udp_hslot),
3434 uhash_entries,
3435 21, /* one slot per 2 MB */
3436 0,
3437 &table->log,
3438 &table->mask,
3439 UDP_HTABLE_SIZE_MIN,
3440 UDP_HTABLE_SIZE_MAX);
3441
3442 table->hash2 = table->hash + (table->mask + 1);
3443 for (i = 0; i <= table->mask; i++) {
3444 INIT_HLIST_HEAD(&table->hash[i].head);
3445 table->hash[i].count = 0;
3446 spin_lock_init(&table->hash[i].lock);
3447 }
3448 for (i = 0; i <= table->mask; i++) {
3449 INIT_HLIST_HEAD(&table->hash2[i].head);
3450 table->hash2[i].count = 0;
3451 spin_lock_init(&table->hash2[i].lock);
3452 }
3453 }
3454
3455 u32 udp_flow_hashrnd(void)
3456 {
3457 static u32 hashrnd __read_mostly;
3458
3459 net_get_random_once(&hashrnd, sizeof(hashrnd));
3460
3461 return hashrnd;
3462 }
3463 EXPORT_SYMBOL(udp_flow_hashrnd);
3464
3465 static void __net_init udp_sysctl_init(struct net *net)
3466 {
3467 net->ipv4.sysctl_udp_rmem_min = PAGE_SIZE;
3468 net->ipv4.sysctl_udp_wmem_min = PAGE_SIZE;
3469
3470 #ifdef CONFIG_NET_L3_MASTER_DEV
3471 net->ipv4.sysctl_udp_l3mdev_accept = 0;
3472 #endif
3473 }
3474
3475 static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_entries)
3476 {
3477 struct udp_table *udptable;
3478 int i;
3479
3480 udptable = kmalloc(sizeof(*udptable), GFP_KERNEL);
3481 if (!udptable)
3482 goto out;
3483
3484 udptable->hash = vmalloc_huge(hash_entries * 2 * sizeof(struct udp_hslot),
3485 GFP_KERNEL_ACCOUNT);
3486 if (!udptable->hash)
3487 goto free_table;
3488
3489 udptable->hash2 = udptable->hash + hash_entries;
3490 udptable->mask = hash_entries - 1;
3491 udptable->log = ilog2(hash_entries);
3492
3493 for (i = 0; i < hash_entries; i++) {
3494 INIT_HLIST_HEAD(&udptable->hash[i].head);
3495 udptable->hash[i].count = 0;
3496 spin_lock_init(&udptable->hash[i].lock);
3497
3498 INIT_HLIST_HEAD(&udptable->hash2[i].head);
3499 udptable->hash2[i].count = 0;
3500 spin_lock_init(&udptable->hash2[i].lock);
3501 }
3502
3503 return udptable;
3504
3505 free_table:
3506 kfree(udptable);
3507 out:
3508 return NULL;
3509 }
3510
3511 static void __net_exit udp_pernet_table_free(struct net *net)
3512 {
3513 struct udp_table *udptable = net->ipv4.udp_table;
3514
3515 if (udptable == &udp_table)
3516 return;
3517
3518 kvfree(udptable->hash);
3519 kfree(udptable);
3520 }
3521
3522 static void __net_init udp_set_table(struct net *net)
3523 {
3524 struct udp_table *udptable;
3525 unsigned int hash_entries;
3526 struct net *old_net;
3527
3528 if (net_eq(net, &init_net))
3529 goto fallback;
3530
3531 old_net = current->nsproxy->net_ns;
3532 hash_entries = READ_ONCE(old_net->ipv4.sysctl_udp_child_hash_entries);
3533 if (!hash_entries)
3534 goto fallback;
3535
3536 /* Set min to keep the bitmap on stack in udp_lib_get_port() */
3537 if (hash_entries < UDP_HTABLE_SIZE_MIN_PERNET)
3538 hash_entries = UDP_HTABLE_SIZE_MIN_PERNET;
3539 else
3540 hash_entries = roundup_pow_of_two(hash_entries);
3541
3542 udptable = udp_pernet_table_alloc(hash_entries);
3543 if (udptable) {
3544 net->ipv4.udp_table = udptable;
3545 } else {
3546 pr_warn("Failed to allocate UDP hash table (entries: %u) "
3547 "for a netns, fallback to the global one\n",
3548 hash_entries);
3549 fallback:
3550 net->ipv4.udp_table = &udp_table;
3551 }
3552 }
3553
3554 static int __net_init udp_pernet_init(struct net *net)
3555 {
3556 udp_sysctl_init(net);
3557 udp_set_table(net);
3558
3559 return 0;
3560 }
3561
3562 static void __net_exit udp_pernet_exit(struct net *net)
3563 {
3564 udp_pernet_table_free(net);
3565 }
3566
3567 static struct pernet_operations __net_initdata udp_sysctl_ops = {
3568 .init = udp_pernet_init,
3569 .exit = udp_pernet_exit,
3570 };
3571
3572 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3573 DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta,
3574 struct udp_sock *udp_sk, uid_t uid, int bucket)
3575
3576 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
3577 unsigned int new_batch_sz)
3578 {
3579 struct sock **new_batch;
3580
3581 new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch),
3582 GFP_USER | __GFP_NOWARN);
3583 if (!new_batch)
3584 return -ENOMEM;
3585
3586 bpf_iter_udp_put_batch(iter);
3587 kvfree(iter->batch);
3588 iter->batch = new_batch;
3589 iter->max_sk = new_batch_sz;
3590
3591 return 0;
3592 }
3593
3594 #define INIT_BATCH_SZ 16
3595
3596 static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux)
3597 {
3598 struct bpf_udp_iter_state *iter = priv_data;
3599 int ret;
3600
3601 ret = bpf_iter_init_seq_net(priv_data, aux);
3602 if (ret)
3603 return ret;
3604
3605 ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ);
3606 if (ret)
3607 bpf_iter_fini_seq_net(priv_data);
3608
3609 return ret;
3610 }
3611
3612 static void bpf_iter_fini_udp(void *priv_data)
3613 {
3614 struct bpf_udp_iter_state *iter = priv_data;
3615
3616 bpf_iter_fini_seq_net(priv_data);
3617 kvfree(iter->batch);
3618 }
3619
3620 static const struct bpf_iter_seq_info udp_seq_info = {
3621 .seq_ops = &bpf_iter_udp_seq_ops,
3622 .init_seq_private = bpf_iter_init_udp,
3623 .fini_seq_private = bpf_iter_fini_udp,
3624 .seq_priv_size = sizeof(struct bpf_udp_iter_state),
3625 };
3626
3627 static struct bpf_iter_reg udp_reg_info = {
3628 .target = "udp",
3629 .ctx_arg_info_size = 1,
3630 .ctx_arg_info = {
3631 { offsetof(struct bpf_iter__udp, udp_sk),
3632 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
3633 },
3634 .seq_info = &udp_seq_info,
3635 };
3636
3637 static void __init bpf_iter_register(void)
3638 {
3639 udp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UDP];
3640 if (bpf_iter_reg_target(&udp_reg_info))
3641 pr_warn("Warning: could not register bpf iterator udp\n");
3642 }
3643 #endif
3644
3645 void __init udp_init(void)
3646 {
3647 unsigned long limit;
3648 unsigned int i;
3649
3650 udp_table_init(&udp_table, "UDP");
3651 limit = nr_free_buffer_pages() / 8;
3652 limit = max(limit, 128UL);
3653 sysctl_udp_mem[0] = limit / 4 * 3;
3654 sysctl_udp_mem[1] = limit;
3655 sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
3656
3657 /* 16 spinlocks per cpu */
3658 udp_busylocks_log = ilog2(nr_cpu_ids) + 4;
3659 udp_busylocks = kmalloc(sizeof(spinlock_t) << udp_busylocks_log,
3660 GFP_KERNEL);
3661 if (!udp_busylocks)
3662 panic("UDP: failed to alloc udp_busylocks\n");
3663 for (i = 0; i < (1U << udp_busylocks_log); i++)
3664 spin_lock_init(udp_busylocks + i);
3665
3666 if (register_pernet_subsys(&udp_sysctl_ops))
3667 panic("UDP: failed to init sysctl parameters.\n");
3668
3669 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3670 bpf_iter_register();
3671 #endif
3672 }
3673
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