xref: /linux/net/ipv6/udp.c (revision ac76cab50e899a7346408b8d3c3a4192c2eefb9f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	UDP over IPv6
4  *	Linux INET6 implementation
5  *
6  *	Authors:
7  *	Pedro Roque		<roque@di.fc.ul.pt>
8  *
9  *	Based on linux/ipv4/udp.c
10  *
11  *	Fixes:
12  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
13  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
14  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
15  *					a single port at the same time.
16  *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
17  *      YOSHIFUJI Hideaki @USAGI:	convert /proc/net/udp6 to seq_file.
18  */
19 
20 #include <linux/bpf-cgroup.h>
21 #include <linux/errno.h>
22 #include <linux/types.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/net.h>
26 #include <linux/in6.h>
27 #include <linux/netdevice.h>
28 #include <linux/if_arp.h>
29 #include <linux/ipv6.h>
30 #include <linux/icmpv6.h>
31 #include <linux/init.h>
32 #include <linux/module.h>
33 #include <linux/skbuff.h>
34 #include <linux/slab.h>
35 #include <linux/uaccess.h>
36 #include <linux/indirect_call_wrapper.h>
37 #include <trace/events/udp.h>
38 
39 #include <net/addrconf.h>
40 #include <net/aligned_data.h>
41 #include <net/ndisc.h>
42 #include <net/protocol.h>
43 #include <net/transp_v6.h>
44 #include <net/ip6_route.h>
45 #include <net/raw.h>
46 #include <net/seg6.h>
47 #include <net/tcp_states.h>
48 #include <net/ip6_checksum.h>
49 #include <net/ip6_tunnel.h>
50 #include <net/udp_tunnel.h>
51 #include <net/xfrm.h>
52 #include <net/inet_hashtables.h>
53 #include <net/inet6_hashtables.h>
54 #include <net/busy_poll.h>
55 #include <net/sock_reuseport.h>
56 #include <net/gro.h>
57 
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <trace/events/skb.h>
61 
62 static void udpv6_destruct_sock(struct sock *sk)
63 {
64 	udp_destruct_common(sk);
65 	inet6_sock_destruct(sk);
66 }
67 
68 static int udpv6_init_sock(struct sock *sk)
69 {
70 	int res = udp_lib_init_sock(sk);
71 
72 	sk->sk_destruct = udpv6_destruct_sock;
73 	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
74 	return res;
75 }
76 
77 INDIRECT_CALLABLE_SCOPE
78 u32 udp6_ehashfn(const struct net *net,
79 		 const struct in6_addr *laddr,
80 		 const u16 lport,
81 		 const struct in6_addr *faddr,
82 		 const __be16 fport)
83 {
84 	u32 lhash, fhash;
85 
86 	net_get_random_once(&udp6_ehash_secret,
87 			    sizeof(udp6_ehash_secret));
88 	net_get_random_once(&udp_ipv6_hash_secret,
89 			    sizeof(udp_ipv6_hash_secret));
90 
91 	lhash = (__force u32)laddr->s6_addr32[3];
92 	fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
93 
94 	return __inet6_ehashfn(lhash, lport, fhash, fport,
95 			       udp6_ehash_secret + net_hash_mix(net));
96 }
97 
98 static int udp_v6_get_port(struct sock *sk, unsigned short snum)
99 {
100 	unsigned int hash2_nulladdr =
101 		ipv6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
102 	unsigned int hash2_partial =
103 		ipv6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
104 
105 	/* precompute partial secondary hash */
106 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
107 	return udp_lib_get_port(sk, snum, hash2_nulladdr);
108 }
109 
110 static void udp_v6_rehash(struct sock *sk)
111 {
112 	u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
113 					  &sk->sk_v6_rcv_saddr,
114 					  inet_sk(sk)->inet_num);
115 	u16 new_hash4;
116 
117 	if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) {
118 		new_hash4 = udp_ehashfn(sock_net(sk),
119 					sk->sk_rcv_saddr, sk->sk_num,
120 					sk->sk_daddr, sk->sk_dport);
121 	} else {
122 		new_hash4 = udp6_ehashfn(sock_net(sk),
123 					 &sk->sk_v6_rcv_saddr, sk->sk_num,
124 					 &sk->sk_v6_daddr, sk->sk_dport);
125 	}
126 
127 	udp_lib_rehash(sk, new_hash, new_hash4);
128 }
129 
130 static __always_inline int
131 compute_score(struct sock *sk, const struct net *net,
132 	      const struct in6_addr *saddr, __be16 sport,
133 	      const struct in6_addr *daddr, unsigned short hnum,
134 	      int dif, int sdif)
135 {
136 	int bound_dev_if, score;
137 	struct inet_sock *inet;
138 	bool dev_match;
139 
140 	if (!net_eq(sock_net(sk), net) ||
141 	    udp_sk(sk)->udp_port_hash != hnum ||
142 	    sk->sk_family != PF_INET6)
143 		return -1;
144 
145 	if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
146 		return -1;
147 
148 	score = 0;
149 	inet = inet_sk(sk);
150 
151 	if (inet->inet_dport) {
152 		if (inet->inet_dport != sport)
153 			return -1;
154 		score++;
155 	}
156 
157 	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
158 		if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
159 			return -1;
160 		score++;
161 	}
162 
163 	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
164 	dev_match = udp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif);
165 	if (!dev_match)
166 		return -1;
167 	if (bound_dev_if)
168 		score++;
169 
170 	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
171 		score++;
172 
173 	return score;
174 }
175 
176 /**
177  * udp6_lib_lookup1() - Simplified lookup using primary hash (destination port)
178  * @net:	Network namespace
179  * @saddr:	Source address, network order
180  * @sport:	Source port, network order
181  * @daddr:	Destination address, network order
182  * @hnum:	Destination port, host order
183  * @dif:	Destination interface index
184  * @sdif:	Destination bridge port index, if relevant
185  * @udptable:	Set of UDP hash tables
186  *
187  * Simplified lookup to be used as fallback if no sockets are found due to a
188  * potential race between (receive) address change, and lookup happening before
189  * the rehash operation. This function ignores SO_REUSEPORT groups while scoring
190  * result sockets, because if we have one, we don't need the fallback at all.
191  *
192  * Called under rcu_read_lock().
193  *
194  * Return: socket with highest matching score if any, NULL if none
195  */
196 static struct sock *udp6_lib_lookup1(const struct net *net,
197 				     const struct in6_addr *saddr, __be16 sport,
198 				     const struct in6_addr *daddr,
199 				     unsigned int hnum, int dif, int sdif,
200 				     const struct udp_table *udptable)
201 {
202 	unsigned int slot = udp_hashfn(net, hnum, udptable->mask);
203 	struct udp_hslot *hslot = &udptable->hash[slot];
204 	struct sock *sk, *result = NULL;
205 	int score, badness = 0;
206 
207 	sk_for_each_rcu(sk, &hslot->head) {
208 		score = compute_score(sk, net,
209 				      saddr, sport, daddr, hnum, dif, sdif);
210 		if (score > badness) {
211 			result = sk;
212 			badness = score;
213 		}
214 	}
215 
216 	return result;
217 }
218 
219 /* called with rcu_read_lock() */
220 static struct sock *udp6_lib_lookup2(const struct net *net,
221 		const struct in6_addr *saddr, __be16 sport,
222 		const struct in6_addr *daddr, unsigned int hnum,
223 		int dif, int sdif, struct udp_hslot *hslot2,
224 		struct sk_buff *skb)
225 {
226 	struct sock *sk, *result;
227 	int score, badness;
228 	bool need_rescore;
229 
230 	result = NULL;
231 	badness = -1;
232 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
233 		need_rescore = false;
234 rescore:
235 		score = compute_score(need_rescore ? result : sk, net, saddr,
236 				      sport, daddr, hnum, dif, sdif);
237 		if (score > badness) {
238 			badness = score;
239 
240 			if (need_rescore)
241 				continue;
242 
243 			if (sk->sk_state == TCP_ESTABLISHED) {
244 				result = sk;
245 				continue;
246 			}
247 
248 			result = inet6_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
249 							saddr, sport, daddr, hnum, udp6_ehashfn);
250 			if (!result) {
251 				result = sk;
252 				continue;
253 			}
254 
255 			/* Fall back to scoring if group has connections */
256 			if (!reuseport_has_conns(sk))
257 				return result;
258 
259 			/* Reuseport logic returned an error, keep original score. */
260 			if (IS_ERR(result))
261 				continue;
262 
263 			/* compute_score is too long of a function to be
264 			 * inlined twice here, and calling it uninlined
265 			 * here yields measurable overhead for some
266 			 * workloads. Work around it by jumping
267 			 * backwards to rescore 'result'.
268 			 */
269 			need_rescore = true;
270 			goto rescore;
271 		}
272 	}
273 	return result;
274 }
275 
276 #if IS_ENABLED(CONFIG_BASE_SMALL)
277 static struct sock *udp6_lib_lookup4(const struct net *net,
278 				     const struct in6_addr *saddr, __be16 sport,
279 				     const struct in6_addr *daddr,
280 				     unsigned int hnum, int dif, int sdif,
281 				     struct udp_table *udptable)
282 {
283 	return NULL;
284 }
285 
286 static void udp6_hash4(struct sock *sk)
287 {
288 }
289 #else /* !CONFIG_BASE_SMALL */
290 static struct sock *udp6_lib_lookup4(const struct net *net,
291 				     const struct in6_addr *saddr, __be16 sport,
292 				     const struct in6_addr *daddr,
293 				     unsigned int hnum, int dif, int sdif,
294 				     struct udp_table *udptable)
295 {
296 	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
297 	const struct hlist_nulls_node *node;
298 	struct udp_hslot *hslot4;
299 	unsigned int hash4, slot;
300 	struct udp_sock *up;
301 	struct sock *sk;
302 
303 	hash4 = udp6_ehashfn(net, daddr, hnum, saddr, sport);
304 	slot = hash4 & udptable->mask;
305 	hslot4 = &udptable->hash4[slot];
306 
307 begin:
308 	udp_lrpa_for_each_entry_rcu(up, node, &hslot4->nulls_head) {
309 		sk = (struct sock *)up;
310 		if (inet6_match(net, sk, saddr, daddr, ports, dif, sdif))
311 			return sk;
312 	}
313 
314 	/* if the nulls value we got at the end of this lookup is not the
315 	 * expected one, we must restart lookup. We probably met an item that
316 	 * was moved to another chain due to rehash.
317 	 */
318 	if (get_nulls_value(node) != slot)
319 		goto begin;
320 
321 	return NULL;
322 }
323 
324 static void udp6_hash4(struct sock *sk)
325 {
326 	struct net *net = sock_net(sk);
327 	unsigned int hash;
328 
329 	if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) {
330 		udp4_hash4(sk);
331 		return;
332 	}
333 
334 	if (sk_unhashed(sk) || ipv6_addr_any(&sk->sk_v6_rcv_saddr))
335 		return;
336 
337 	hash = udp6_ehashfn(net, &sk->sk_v6_rcv_saddr, sk->sk_num,
338 			    &sk->sk_v6_daddr, sk->sk_dport);
339 
340 	udp_lib_hash4(sk, hash);
341 }
342 #endif /* CONFIG_BASE_SMALL */
343 
344 /* rcu_read_lock() must be held */
345 struct sock *__udp6_lib_lookup(const struct net *net,
346 			       const struct in6_addr *saddr, __be16 sport,
347 			       const struct in6_addr *daddr, __be16 dport,
348 			       int dif, int sdif, struct sk_buff *skb)
349 {
350 	struct udp_table *udptable = net->ipv4.udp_table;
351 	unsigned short hnum = ntohs(dport);
352 	struct udp_hslot *hslot2;
353 	struct sock *result, *sk;
354 	unsigned int hash2;
355 
356 	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
357 	hslot2 = udp_hashslot2(udptable, hash2);
358 
359 	if (udp_has_hash4(hslot2)) {
360 		result = udp6_lib_lookup4(net, saddr, sport, daddr, hnum,
361 					  dif, sdif, udptable);
362 		if (result) /* udp6_lib_lookup4 return sk or NULL */
363 			return result;
364 	}
365 
366 	/* Lookup connected or non-wildcard sockets */
367 	result = udp6_lib_lookup2(net, saddr, sport,
368 				  daddr, hnum, dif, sdif,
369 				  hslot2, skb);
370 	if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED)
371 		goto done;
372 
373 	/* Lookup redirect from BPF */
374 	if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
375 		sk = inet6_lookup_run_sk_lookup(net, IPPROTO_UDP, skb, sizeof(struct udphdr),
376 						saddr, sport, daddr, hnum, dif,
377 						udp6_ehashfn);
378 		if (sk) {
379 			result = sk;
380 			goto done;
381 		}
382 	}
383 
384 	/* Got non-wildcard socket or error on first lookup */
385 	if (result)
386 		goto done;
387 
388 	/* Lookup wildcard sockets */
389 	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
390 	hslot2 = udp_hashslot2(udptable, hash2);
391 
392 	result = udp6_lib_lookup2(net, saddr, sport,
393 				  &in6addr_any, hnum, dif, sdif,
394 				  hslot2, skb);
395 	if (!IS_ERR_OR_NULL(result))
396 		goto done;
397 
398 	/* Cover address change/lookup/rehash race: see __udp4_lib_lookup() */
399 	result = udp6_lib_lookup1(net, saddr, sport, daddr, hnum, dif, sdif,
400 				  udptable);
401 
402 done:
403 	if (IS_ERR(result))
404 		return NULL;
405 	return result;
406 }
407 EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
408 
409 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
410 					  __be16 sport, __be16 dport)
411 {
412 	const struct ipv6hdr *iph = ipv6_hdr(skb);
413 
414 	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
415 				 &iph->daddr, dport, inet6_iif(skb),
416 				 inet6_sdif(skb), skb);
417 }
418 
419 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
420 				 __be16 sport, __be16 dport)
421 {
422 	const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
423 	const struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + offset);
424 	int iif, sdif;
425 
426 	inet6_get_iif_sdif(skb, &iif, &sdif);
427 
428 	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
429 				 &iph->daddr, dport, iif, sdif, NULL);
430 }
431 
432 /* Must be called under rcu_read_lock().
433  * Does increment socket refcount.
434  */
435 #if IS_ENABLED(CONFIG_NF_TPROXY_IPV6) || IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
436 struct sock *udp6_lib_lookup(const struct net *net, const struct in6_addr *saddr, __be16 sport,
437 			     const struct in6_addr *daddr, __be16 dport, int dif)
438 {
439 	struct sock *sk;
440 
441 	sk =  __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, 0, NULL);
442 	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
443 		sk = NULL;
444 	return sk;
445 }
446 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
447 #endif
448 
449 /* do not use the scratch area len for jumbogram: their length exceeds the
450  * scratch area space; note that the IP6CB flags is still in the first
451  * cacheline, so checking for jumbograms is cheap
452  */
453 static int udp6_skb_len(struct sk_buff *skb)
454 {
455 	return unlikely(inet6_is_jumbogram(skb)) ? skb->len : udp_skb_len(skb);
456 }
457 
458 /*
459  *	This should be easy, if there is something there we
460  *	return it, otherwise we block.
461  */
462 
463 INDIRECT_CALLABLE_SCOPE
464 int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
465 		  int flags)
466 {
467 	int off, is_udp4, err, peeking = flags & MSG_PEEK;
468 	struct ipv6_pinfo *np = inet6_sk(sk);
469 	struct inet_sock *inet = inet_sk(sk);
470 	struct udp_mib __percpu *mib;
471 	bool checksum_valid = false;
472 	unsigned int ulen, copied;
473 	struct sk_buff *skb;
474 
475 	if (flags & MSG_ERRQUEUE)
476 		return ipv6_recv_error(sk, msg, len);
477 
478 	if (np->rxopt.bits.rxpmtu && READ_ONCE(np->rxpmtu))
479 		return ipv6_recv_rxpmtu(sk, msg, len);
480 
481 try_again:
482 	off = sk_peek_offset(sk, flags);
483 	skb = __skb_recv_udp(sk, flags, &off, &err);
484 	if (!skb)
485 		return err;
486 
487 	ulen = udp6_skb_len(skb);
488 	copied = len;
489 	if (copied > ulen - off)
490 		copied = ulen - off;
491 	else if (copied < ulen)
492 		msg->msg_flags |= MSG_TRUNC;
493 
494 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
495 	mib = __UDPX_MIB(sk, is_udp4);
496 
497 	/* If checksum is needed at all, try to do it while copying the
498 	 * data.  If the data is truncated, do it before the copy.
499 	 */
500 	if (copied < ulen || peeking) {
501 		checksum_valid = udp_skb_csum_unnecessary(skb) ||
502 				!__udp_lib_checksum_complete(skb);
503 		if (!checksum_valid)
504 			goto csum_copy_err;
505 	}
506 
507 	if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
508 		if (udp_skb_is_linear(skb))
509 			err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
510 		else
511 			err = skb_copy_datagram_msg(skb, off, msg, copied);
512 	} else {
513 		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
514 		if (err == -EINVAL)
515 			goto csum_copy_err;
516 	}
517 	if (unlikely(err)) {
518 		if (!peeking) {
519 			udp_drops_inc(sk);
520 			SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
521 		}
522 		kfree_skb(skb);
523 		return err;
524 	}
525 	if (!peeking)
526 		SNMP_INC_STATS(mib, UDP_MIB_INDATAGRAMS);
527 
528 	sock_recv_cmsgs(msg, sk, skb);
529 
530 	/* Copy the address. */
531 	if (msg->msg_name) {
532 		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
533 		sin6->sin6_family = AF_INET6;
534 		sin6->sin6_port = udp_hdr(skb)->source;
535 		sin6->sin6_flowinfo = 0;
536 
537 		if (is_udp4) {
538 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
539 					       &sin6->sin6_addr);
540 			sin6->sin6_scope_id = 0;
541 		} else {
542 			sin6->sin6_addr = ipv6_hdr(skb)->saddr;
543 			sin6->sin6_scope_id =
544 				ipv6_iface_scope_id(&sin6->sin6_addr,
545 						    inet6_iif(skb));
546 		}
547 		msg->msg_namelen = sizeof(*sin6);
548 
549 		BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk,
550 						      (struct sockaddr *)sin6,
551 						      &msg->msg_namelen);
552 	}
553 
554 	if (udp_test_bit(GRO_ENABLED, sk))
555 		udp_cmsg_recv(msg, sk, skb);
556 
557 	if (np->rxopt.all)
558 		ip6_datagram_recv_common_ctl(sk, msg, skb);
559 
560 	if (is_udp4) {
561 		if (inet_cmsg_flags(inet))
562 			ip_cmsg_recv_offset(msg, sk, skb,
563 					    sizeof(struct udphdr), off);
564 	} else {
565 		if (np->rxopt.all)
566 			ip6_datagram_recv_specific_ctl(sk, msg, skb);
567 	}
568 
569 	err = copied;
570 	if (flags & MSG_TRUNC)
571 		err = ulen;
572 
573 	skb_consume_udp(sk, skb, peeking ? -err : err);
574 	return err;
575 
576 csum_copy_err:
577 	if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
578 				 udp_skb_destructor)) {
579 		SNMP_INC_STATS(mib, UDP_MIB_CSUMERRORS);
580 		SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
581 	}
582 	kfree_skb_reason(skb, SKB_DROP_REASON_UDP_CSUM);
583 
584 	/* starting over for a new packet, but check if we need to yield */
585 	cond_resched();
586 	msg->msg_flags &= ~MSG_TRUNC;
587 	goto try_again;
588 }
589 
590 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
591 void udpv6_encap_enable(void)
592 {
593 	static_branch_inc(&udpv6_encap_needed_key);
594 }
595 EXPORT_SYMBOL(udpv6_encap_enable);
596 
597 /* Handler for tunnels with arbitrary destination ports: no socket lookup, go
598  * through error handlers in encapsulations looking for a match.
599  */
600 static int __udp6_lib_err_encap_no_sk(struct sk_buff *skb,
601 				      struct inet6_skb_parm *opt,
602 				      u8 type, u8 code, int offset, __be32 info)
603 {
604 	int i;
605 
606 	for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
607 		int (*handler)(struct sk_buff *skb, struct inet6_skb_parm *opt,
608 			       u8 type, u8 code, int offset, __be32 info);
609 		const struct ip6_tnl_encap_ops *encap;
610 
611 		encap = rcu_dereference(ip6tun_encaps[i]);
612 		if (!encap)
613 			continue;
614 		handler = encap->err_handler;
615 		if (handler && !handler(skb, opt, type, code, offset, info))
616 			return 0;
617 	}
618 
619 	return -ENOENT;
620 }
621 
622 /* Try to match ICMP errors to UDP tunnels by looking up a socket without
623  * reversing source and destination port: this will match tunnels that force the
624  * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
625  * lwtunnels might actually break this assumption by being configured with
626  * different destination ports on endpoints, in this case we won't be able to
627  * trace ICMP messages back to them.
628  *
629  * If this doesn't match any socket, probe tunnels with arbitrary destination
630  * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
631  * we've sent packets to won't necessarily match the local destination port.
632  *
633  * Then ask the tunnel implementation to match the error against a valid
634  * association.
635  *
636  * Return an error if we can't find a match, the socket if we need further
637  * processing, zero otherwise.
638  */
639 static struct sock *__udp6_lib_err_encap(struct net *net,
640 					 const struct ipv6hdr *hdr, int offset,
641 					 struct udphdr *uh,
642 					 struct sock *sk,
643 					 struct sk_buff *skb,
644 					 struct inet6_skb_parm *opt,
645 					 u8 type, u8 code, __be32 info)
646 {
647 	int (*lookup)(struct sock *sk, struct sk_buff *skb);
648 	int network_offset, transport_offset;
649 	struct udp_sock *up;
650 
651 	network_offset = skb_network_offset(skb);
652 	transport_offset = skb_transport_offset(skb);
653 
654 	/* Network header needs to point to the outer IPv6 header inside ICMP */
655 	skb_reset_network_header(skb);
656 
657 	/* Transport header needs to point to the UDP header */
658 	skb_set_transport_header(skb, offset);
659 
660 	if (sk) {
661 		up = udp_sk(sk);
662 
663 		lookup = READ_ONCE(up->encap_err_lookup);
664 		if (lookup && lookup(sk, skb))
665 			sk = NULL;
666 
667 		goto out;
668 	}
669 
670 	sk = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
671 			       &hdr->saddr, uh->dest,
672 			       inet6_iif(skb), 0, skb);
673 	if (sk) {
674 		up = udp_sk(sk);
675 
676 		lookup = READ_ONCE(up->encap_err_lookup);
677 		if (!lookup || lookup(sk, skb))
678 			sk = NULL;
679 	}
680 
681 out:
682 	if (!sk) {
683 		sk = ERR_PTR(__udp6_lib_err_encap_no_sk(skb, opt, type, code,
684 							offset, info));
685 	}
686 
687 	skb_set_transport_header(skb, transport_offset);
688 	skb_set_network_header(skb, network_offset);
689 
690 	return sk;
691 }
692 
693 static void udpv6_err_update_exception(struct net *net, struct sk_buff *skb,
694 				       u8 type, __be32 info)
695 {
696 	if (type == ICMPV6_PKT_TOOBIG)
697 		ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0,
698 				sock_net_uid(net, NULL));
699 	else if (type == NDISC_REDIRECT)
700 		ip6_redirect(skb, net, skb->dev->ifindex, 0,
701 			     sock_net_uid(net, NULL));
702 }
703 
704 static int udpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
705 		     u8 type, u8 code, int offset, __be32 info)
706 {
707 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
708 	struct udphdr *uh = (struct udphdr *)(skb->data + offset);
709 	const struct in6_addr *saddr, *daddr;
710 	struct net *net = dev_net(skb->dev);
711 	struct ipv6_pinfo *np;
712 	bool tunnel = false;
713 	struct sock *sk;
714 	int harderr;
715 	int err;
716 
717 	udpv6_err_update_exception(net, skb, type, info);
718 
719 	daddr = seg6_get_daddr(skb, opt) ? : &hdr->daddr;
720 	saddr = &hdr->saddr;
721 	sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
722 			       inet6_iif(skb), inet6_sdif(skb), NULL);
723 
724 	if (!sk || READ_ONCE(udp_sk(sk)->encap_type)) {
725 		/* No socket for error: try tunnels before discarding */
726 		if (static_branch_unlikely(&udpv6_encap_needed_key)) {
727 			sk = __udp6_lib_err_encap(net, hdr, offset, uh, sk, skb,
728 						  opt, type, code, info);
729 			if (!sk)
730 				return 0;
731 		} else
732 			sk = ERR_PTR(-ENOENT);
733 
734 		if (IS_ERR(sk)) {
735 			__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
736 					  ICMP6_MIB_INERRORS);
737 			return PTR_ERR(sk);
738 		}
739 
740 		tunnel = true;
741 	}
742 
743 	harderr = icmpv6_err_convert(type, code, &err);
744 	np = inet6_sk(sk);
745 
746 	if (type == ICMPV6_PKT_TOOBIG) {
747 		if (!ip6_sk_accept_pmtu(sk))
748 			goto out;
749 		ip6_sk_update_pmtu(skb, sk, info);
750 		if (READ_ONCE(np->pmtudisc) != IPV6_PMTUDISC_DONT)
751 			harderr = 1;
752 	}
753 	if (type == NDISC_REDIRECT) {
754 		if (tunnel) {
755 			ip6_redirect(skb, sock_net(sk), inet6_iif(skb),
756 				     READ_ONCE(sk->sk_mark),
757 				     sk_uid(sk));
758 		} else {
759 			ip6_sk_redirect(skb, sk);
760 		}
761 		goto out;
762 	}
763 
764 	/* Tunnels don't have an application socket: don't pass errors back */
765 	if (tunnel) {
766 		if (udp_sk(sk)->encap_err_rcv)
767 			udp_sk(sk)->encap_err_rcv(sk, skb, err, uh->dest,
768 						  ntohl(info), (u8 *)(uh+1));
769 		goto out;
770 	}
771 
772 	if (!inet6_test_bit(RECVERR6, sk)) {
773 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
774 			goto out;
775 	} else {
776 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
777 	}
778 
779 	sk->sk_err = err;
780 	sk_error_report(sk);
781 out:
782 	return 0;
783 }
784 
785 static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
786 {
787 	int rc;
788 
789 	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
790 		sock_rps_save_rxhash(sk, skb);
791 		sk_mark_napi_id(sk, skb);
792 		sk_incoming_cpu_update(sk);
793 	} else {
794 		sk_mark_napi_id_once(sk, skb);
795 	}
796 
797 	rc = __udp_enqueue_schedule_skb(sk, skb);
798 	if (rc < 0) {
799 		enum skb_drop_reason drop_reason;
800 		struct net *net = sock_net(sk);
801 
802 		/* Note that an ENOMEM error is charged twice */
803 		if (rc == -ENOMEM) {
804 			UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS);
805 			drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
806 		} else {
807 			UDP6_INC_STATS(net, UDP_MIB_MEMERRORS);
808 			drop_reason = SKB_DROP_REASON_PROTO_MEM;
809 		}
810 		UDP6_INC_STATS(net, UDP_MIB_INERRORS);
811 		trace_udp_fail_queue_rcv_skb(rc, sk, skb);
812 		sk_skb_reason_drop(sk, skb, drop_reason);
813 		return -1;
814 	}
815 
816 	return 0;
817 }
818 
819 static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
820 {
821 	enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
822 	struct udp_sock *up = udp_sk(sk);
823 	struct net *net = sock_net(sk);
824 
825 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
826 		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
827 		goto drop;
828 	}
829 	nf_reset_ct(skb);
830 
831 	if (static_branch_unlikely(&udpv6_encap_needed_key) &&
832 	    READ_ONCE(up->encap_type)) {
833 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
834 
835 		/*
836 		 * This is an encapsulation socket so pass the skb to
837 		 * the socket's udp_encap_rcv() hook. Otherwise, just
838 		 * fall through and pass this up the UDP socket.
839 		 * up->encap_rcv() returns the following value:
840 		 * =0 if skb was successfully passed to the encap
841 		 *    handler or was discarded by it.
842 		 * >0 if skb should be passed on to UDP.
843 		 * <0 if skb should be resubmitted as proto -N
844 		 */
845 
846 		/* if we're overly short, let UDP handle it */
847 		encap_rcv = READ_ONCE(up->encap_rcv);
848 		if (encap_rcv) {
849 			int ret;
850 
851 			/* Verify checksum before giving to encap */
852 			if (udp_lib_checksum_complete(skb))
853 				goto csum_error;
854 
855 			ret = encap_rcv(sk, skb);
856 			if (ret <= 0) {
857 				__UDP6_INC_STATS(net, UDP_MIB_INDATAGRAMS);
858 				return -ret;
859 			}
860 		}
861 
862 		/* FALLTHROUGH -- it's a UDP Packet */
863 	}
864 
865 	prefetch(&sk->sk_rmem_alloc);
866 	if (rcu_access_pointer(sk->sk_filter) &&
867 	    udp_lib_checksum_complete(skb))
868 		goto csum_error;
869 
870 	drop_reason = sk_filter_trim_cap(sk, skb, sizeof(struct udphdr));
871 	if (drop_reason)
872 		goto drop;
873 
874 	udp_csum_pull_header(skb);
875 
876 	skb_dst_drop(skb);
877 
878 	return __udpv6_queue_rcv_skb(sk, skb);
879 
880 csum_error:
881 	drop_reason = SKB_DROP_REASON_UDP_CSUM;
882 	__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS);
883 drop:
884 	__UDP6_INC_STATS(net, UDP_MIB_INERRORS);
885 	udp_drops_inc(sk);
886 	sk_skb_reason_drop(sk, skb, drop_reason);
887 	return -1;
888 }
889 
890 static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
891 {
892 	struct sk_buff *next, *segs;
893 	int ret;
894 
895 	if (likely(!udp_unexpected_gso(sk, skb)))
896 		return udpv6_queue_rcv_one_skb(sk, skb);
897 
898 	__skb_push(skb, -skb_mac_offset(skb));
899 	segs = udp_rcv_segment(sk, skb, false);
900 	skb_list_walk_safe(segs, skb, next) {
901 		__skb_pull(skb, skb_transport_offset(skb));
902 
903 		udp_post_segment_fix_csum(skb);
904 		ret = udpv6_queue_rcv_one_skb(sk, skb);
905 		if (ret > 0)
906 			ip6_protocol_deliver_rcu(dev_net(skb->dev), skb, ret,
907 						 true);
908 	}
909 	return 0;
910 }
911 
912 static bool __udp_v6_is_mcast_sock(struct net *net, const struct sock *sk,
913 				   __be16 loc_port, const struct in6_addr *loc_addr,
914 				   __be16 rmt_port, const struct in6_addr *rmt_addr,
915 				   int dif, int sdif, unsigned short hnum)
916 {
917 	const struct inet_sock *inet = inet_sk(sk);
918 
919 	if (!net_eq(sock_net(sk), net))
920 		return false;
921 
922 	if (udp_sk(sk)->udp_port_hash != hnum ||
923 	    sk->sk_family != PF_INET6 ||
924 	    (inet->inet_dport && inet->inet_dport != rmt_port) ||
925 	    (!ipv6_addr_any(&sk->sk_v6_daddr) &&
926 		    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
927 	    !udp_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif, sdif) ||
928 	    (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
929 		    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
930 		return false;
931 	if (!inet6_mc_check(sk, loc_addr, rmt_addr))
932 		return false;
933 	return true;
934 }
935 
936 static void udp6_csum_zero_error(struct sk_buff *skb)
937 {
938 	/* RFC 2460 section 8.1 says that we SHOULD log
939 	 * this error. Well, it is reasonable.
940 	 */
941 	net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
942 			    &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
943 			    &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
944 }
945 
946 /*
947  * Note: called only from the BH handler context,
948  * so we don't need to lock the hashes.
949  */
950 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
951 				    const struct in6_addr *saddr,
952 				    const struct in6_addr *daddr)
953 {
954 	struct udp_table *udptable = net->ipv4.udp_table;
955 	const struct udphdr *uh = udp_hdr(skb);
956 	unsigned int hash2, hash2_any, offset;
957 	unsigned short hnum = ntohs(uh->dest);
958 	struct sock *sk, *first = NULL;
959 	int sdif = inet6_sdif(skb);
960 	int dif = inet6_iif(skb);
961 	struct hlist_node *node;
962 	struct udp_hslot *hslot;
963 	struct sk_buff *nskb;
964 	bool use_hash2;
965 	int ret;
966 
967 	hash2_any = 0;
968 	hash2 = 0;
969 	hslot = udp_hashslot(udptable, net, hnum);
970 	use_hash2 = hslot->count > 10;
971 	offset = offsetof(typeof(*sk), sk_node);
972 
973 	if (use_hash2) {
974 		hash2_any = ipv6_portaddr_hash(net, &in6addr_any, hnum) &
975 			    udptable->mask;
976 		hash2 = ipv6_portaddr_hash(net, daddr, hnum) & udptable->mask;
977 start_lookup:
978 		hslot = &udptable->hash2[hash2].hslot;
979 		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
980 	}
981 
982 	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
983 		if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr,
984 					    uh->source, saddr, dif, sdif,
985 					    hnum))
986 			continue;
987 		/* If zero checksum and no_check is not on for
988 		 * the socket then skip it.
989 		 */
990 		if (!uh->check && !udp_get_no_check6_rx(sk))
991 			continue;
992 		if (!first) {
993 			first = sk;
994 			continue;
995 		}
996 		nskb = skb_clone(skb, GFP_ATOMIC);
997 		if (unlikely(!nskb)) {
998 			udp_drops_inc(sk);
999 			__UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS);
1000 			__UDP6_INC_STATS(net, UDP_MIB_INERRORS);
1001 			continue;
1002 		}
1003 
1004 		if (udpv6_queue_rcv_skb(sk, nskb) > 0)
1005 			consume_skb(nskb);
1006 	}
1007 
1008 	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
1009 	if (use_hash2 && hash2 != hash2_any) {
1010 		hash2 = hash2_any;
1011 		goto start_lookup;
1012 	}
1013 
1014 	if (first) {
1015 		ret = udpv6_queue_rcv_skb(first, skb);
1016 		if (ret > 0)
1017 			return ret;
1018 	} else {
1019 		kfree_skb(skb);
1020 		__UDP6_INC_STATS(net, UDP_MIB_IGNOREDMULTI);
1021 	}
1022 	return 0;
1023 }
1024 
1025 static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
1026 {
1027 	if (udp_sk_rx_dst_set(sk, dst))
1028 		sk->sk_rx_dst_cookie = rt6_get_cookie(dst_rt6_info(dst));
1029 }
1030 
1031 /* wrapper for udp_queue_rcv_skb taking care of csum conversion and
1032  * return code conversion for ip layer consumption
1033  */
1034 static int udp6_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
1035 				struct udphdr *uh)
1036 {
1037 	int ret;
1038 
1039 	if (inet_get_convert_csum(sk) && uh->check)
1040 		skb_checksum_try_convert(skb, IPPROTO_UDP, ip6_compute_pseudo);
1041 
1042 	ret = udpv6_queue_rcv_skb(sk, skb);
1043 
1044 	/* a return value > 0 means to resubmit the input */
1045 	if (ret > 0)
1046 		return ret;
1047 	return 0;
1048 }
1049 
1050 static int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh)
1051 {
1052 	int err;
1053 
1054 	/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
1055 	 * we accept a checksum of zero here. When we find the socket
1056 	 * for the UDP packet we'll check if that socket allows zero checksum
1057 	 * for IPv6 (set by socket option).
1058 	 *
1059 	 * Note, we are only interested in != 0 or == 0, thus the
1060 	 * force to int.
1061 	 */
1062 	err = (__force int)skb_checksum_init_zero_check(skb, IPPROTO_UDP, uh->check,
1063 							ip6_compute_pseudo);
1064 	if (err)
1065 		return err;
1066 
1067 	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
1068 		/* If SW calculated the value, we know it's bad */
1069 		if (skb->csum_complete_sw)
1070 			return 1;
1071 
1072 		/* HW says the value is bad. Let's validate that.
1073 		 * skb->csum is no longer the full packet checksum,
1074 		 * so don't treat is as such.
1075 		 */
1076 		skb_checksum_complete_unset(skb);
1077 	}
1078 
1079 	return 0;
1080 }
1081 
1082 INDIRECT_CALLABLE_SCOPE int udpv6_rcv(struct sk_buff *skb)
1083 {
1084 	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
1085 	const struct in6_addr *saddr, *daddr;
1086 	struct net *net = dev_net(skb->dev);
1087 	struct sock *sk = NULL;
1088 	struct udphdr *uh;
1089 	bool refcounted;
1090 	u32 ulen = 0;
1091 
1092 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1093 		goto discard;
1094 
1095 	saddr = &ipv6_hdr(skb)->saddr;
1096 	daddr = &ipv6_hdr(skb)->daddr;
1097 	uh = udp_hdr(skb);
1098 
1099 	ulen = udp_get_len(skb, uh, 0);
1100 	if (ulen > skb->len)
1101 		goto short_packet;
1102 
1103 	/* Check for jumbo payload */
1104 	if (ulen == 0 && inet6_is_jumbogram(skb))
1105 		ulen = skb->len;
1106 
1107 	if (ulen < sizeof(*uh))
1108 		goto short_packet;
1109 
1110 	if (ulen < skb->len) {
1111 		if (pskb_trim_rcsum(skb, ulen))
1112 			goto short_packet;
1113 
1114 		saddr = &ipv6_hdr(skb)->saddr;
1115 		daddr = &ipv6_hdr(skb)->daddr;
1116 		uh = udp_hdr(skb);
1117 	}
1118 
1119 	if (udp6_csum_init(skb, uh))
1120 		goto csum_error;
1121 
1122 	/* Check if the socket is already available, e.g. due to early demux */
1123 	sk = inet6_steal_sock(net, skb, sizeof(struct udphdr), saddr, uh->source, daddr, uh->dest,
1124 			      &refcounted, udp6_ehashfn);
1125 	if (IS_ERR(sk))
1126 		goto no_sk;
1127 
1128 	if (sk) {
1129 		struct dst_entry *dst = skb_dst(skb);
1130 		int ret;
1131 
1132 		if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
1133 			udp6_sk_rx_dst_set(sk, dst);
1134 
1135 		if (!uh->check && !udp_get_no_check6_rx(sk)) {
1136 			if (refcounted)
1137 				sock_put(sk);
1138 			goto report_csum_error;
1139 		}
1140 
1141 		ret = udp6_unicast_rcv_skb(sk, skb, uh);
1142 		if (refcounted)
1143 			sock_put(sk);
1144 		return ret;
1145 	}
1146 
1147 	/*
1148 	 *	Multicast receive code
1149 	 */
1150 	if (ipv6_addr_is_multicast(daddr))
1151 		return __udp6_lib_mcast_deliver(net, skb, saddr, daddr);
1152 
1153 	/* Unicast */
1154 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest);
1155 	if (sk) {
1156 		if (!uh->check && !udp_get_no_check6_rx(sk))
1157 			goto report_csum_error;
1158 		return udp6_unicast_rcv_skb(sk, skb, uh);
1159 	}
1160 no_sk:
1161 	reason = SKB_DROP_REASON_NO_SOCKET;
1162 
1163 	if (!uh->check)
1164 		goto report_csum_error;
1165 
1166 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
1167 		goto discard;
1168 	nf_reset_ct(skb);
1169 
1170 	if (udp_lib_checksum_complete(skb))
1171 		goto csum_error;
1172 
1173 	__UDP6_INC_STATS(net, UDP_MIB_NOPORTS);
1174 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
1175 
1176 	sk_skb_reason_drop(sk, skb, reason);
1177 	return 0;
1178 
1179 short_packet:
1180 	if (reason == SKB_DROP_REASON_NOT_SPECIFIED)
1181 		reason = SKB_DROP_REASON_PKT_TOO_SMALL;
1182 	net_dbg_ratelimited("UDPv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
1183 			    saddr, ntohs(uh->source),
1184 			    ulen, skb->len,
1185 			    daddr, ntohs(uh->dest));
1186 	goto discard;
1187 
1188 report_csum_error:
1189 	udp6_csum_zero_error(skb);
1190 csum_error:
1191 	if (reason == SKB_DROP_REASON_NOT_SPECIFIED)
1192 		reason = SKB_DROP_REASON_UDP_CSUM;
1193 	__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS);
1194 discard:
1195 	__UDP6_INC_STATS(net, UDP_MIB_INERRORS);
1196 	sk_skb_reason_drop(sk, skb, reason);
1197 	return 0;
1198 }
1199 
1200 
1201 static struct sock *__udp6_lib_demux_lookup(struct net *net,
1202 			__be16 loc_port, const struct in6_addr *loc_addr,
1203 			__be16 rmt_port, const struct in6_addr *rmt_addr,
1204 			int dif, int sdif)
1205 {
1206 	struct udp_table *udptable = net->ipv4.udp_table;
1207 	unsigned short hnum = ntohs(loc_port);
1208 	struct udp_hslot *hslot2;
1209 	unsigned int hash2;
1210 	__portpair ports;
1211 	struct sock *sk;
1212 
1213 	hash2 = ipv6_portaddr_hash(net, loc_addr, hnum);
1214 	hslot2 = udp_hashslot2(udptable, hash2);
1215 	ports = INET_COMBINED_PORTS(rmt_port, hnum);
1216 
1217 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
1218 		if (sk->sk_state == TCP_ESTABLISHED &&
1219 		    inet6_match(net, sk, rmt_addr, loc_addr, ports, dif, sdif))
1220 			return sk;
1221 		/* Only check first socket in chain */
1222 		break;
1223 	}
1224 	return NULL;
1225 }
1226 
1227 void udp_v6_early_demux(struct sk_buff *skb)
1228 {
1229 	struct net *net = dev_net(skb->dev);
1230 	const struct udphdr *uh;
1231 	struct sock *sk;
1232 	struct dst_entry *dst;
1233 	int dif = skb->dev->ifindex;
1234 	int sdif = inet6_sdif(skb);
1235 
1236 	if (!pskb_may_pull(skb, skb_transport_offset(skb) +
1237 	    sizeof(struct udphdr)))
1238 		return;
1239 
1240 	uh = udp_hdr(skb);
1241 
1242 	if (skb->pkt_type == PACKET_HOST)
1243 		sk = __udp6_lib_demux_lookup(net, uh->dest,
1244 					     &ipv6_hdr(skb)->daddr,
1245 					     uh->source, &ipv6_hdr(skb)->saddr,
1246 					     dif, sdif);
1247 	else
1248 		return;
1249 
1250 	if (!sk)
1251 		return;
1252 
1253 	skb->sk = sk;
1254 	DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk));
1255 	skb->destructor = sock_pfree;
1256 	dst = rcu_dereference(sk->sk_rx_dst);
1257 
1258 	if (dst)
1259 		dst = dst_check(dst, sk->sk_rx_dst_cookie);
1260 	if (dst) {
1261 		/* set noref for now.
1262 		 * any place which wants to hold dst has to call
1263 		 * dst_hold_safe()
1264 		 */
1265 		skb_dst_set_noref(skb, dst);
1266 	}
1267 }
1268 
1269 /*
1270  * Throw away all pending data and cancel the corking. Socket is locked.
1271  */
1272 static void udp_v6_flush_pending_frames(struct sock *sk)
1273 {
1274 	struct udp_sock *up = udp_sk(sk);
1275 
1276 	if (up->pending == AF_INET)
1277 		udp_flush_pending_frames(sk);
1278 	else if (up->pending) {
1279 		up->len = 0;
1280 		WRITE_ONCE(up->pending, 0);
1281 		ip6_flush_pending_frames(sk);
1282 	}
1283 }
1284 
1285 static int udpv6_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr,
1286 			     int addr_len)
1287 {
1288 	if (addr_len < offsetofend(struct sockaddr, sa_family))
1289 		return -EINVAL;
1290 	/* The following checks are replicated from __ip6_datagram_connect()
1291 	 * and intended to prevent BPF program called below from accessing
1292 	 * bytes that are out of the bound specified by user in addr_len.
1293 	 */
1294 	if (uaddr->sa_family == AF_INET) {
1295 		if (ipv6_only_sock(sk))
1296 			return -EAFNOSUPPORT;
1297 		return udp_pre_connect(sk, uaddr, addr_len);
1298 	}
1299 
1300 	if (addr_len < SIN6_LEN_RFC2133)
1301 		return -EINVAL;
1302 
1303 	return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr, &addr_len);
1304 }
1305 
1306 static int udpv6_connect(struct sock *sk, struct sockaddr_unsized *uaddr,
1307 			 int addr_len)
1308 {
1309 	int res;
1310 
1311 	lock_sock(sk);
1312 	res = __ip6_datagram_connect(sk, uaddr, addr_len);
1313 	if (!res)
1314 		udp6_hash4(sk);
1315 	release_sock(sk);
1316 	return res;
1317 }
1318 
1319 /**
1320  *	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
1321  *	@sk:	socket we are sending on
1322  *	@skb:	sk_buff containing the filled-in UDP header
1323  *		(checksum field must be zeroed out)
1324  *	@saddr: source address
1325  *	@daddr: destination address
1326  *	@len:	length of packet
1327  */
1328 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
1329 				 const struct in6_addr *saddr,
1330 				 const struct in6_addr *daddr, int len)
1331 {
1332 	unsigned int offset;
1333 	struct udphdr *uh = udp_hdr(skb);
1334 	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
1335 	__wsum csum = 0;
1336 
1337 	if (!frags) {
1338 		/* Only one fragment on the socket.  */
1339 		skb->csum_start = skb_transport_header(skb) - skb->head;
1340 		skb->csum_offset = offsetof(struct udphdr, check);
1341 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
1342 	} else {
1343 		/*
1344 		 * HW-checksum won't work as there are two or more
1345 		 * fragments on the socket so that all csums of sk_buffs
1346 		 * should be together
1347 		 */
1348 		offset = skb_transport_offset(skb);
1349 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
1350 		csum = skb->csum;
1351 
1352 		skb->ip_summed = CHECKSUM_NONE;
1353 
1354 		do {
1355 			csum = csum_add(csum, frags->csum);
1356 		} while ((frags = frags->next));
1357 
1358 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
1359 					    csum);
1360 		if (uh->check == 0)
1361 			uh->check = CSUM_MANGLED_0;
1362 	}
1363 }
1364 
1365 /*
1366  *	Sending
1367  */
1368 
1369 static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
1370 			   struct inet_cork *cork)
1371 {
1372 	struct sock *sk = skb->sk;
1373 	int offset, len, datalen;
1374 	struct udphdr *uh;
1375 	int err = 0;
1376 
1377 	offset = skb_transport_offset(skb);
1378 	len = skb->len - offset;
1379 	datalen = len - sizeof(*uh);
1380 
1381 	/*
1382 	 * Create a UDP header
1383 	 */
1384 	uh = udp_hdr(skb);
1385 	uh->source = fl6->fl6_sport;
1386 	uh->dest = fl6->fl6_dport;
1387 	/* Datagram length checked in udpv6_sendmsg. */
1388 	udp_set_len_short(uh, len);
1389 	uh->check = 0;
1390 
1391 	if (cork->gso_size) {
1392 		const int hlen = skb_network_header_len(skb) +
1393 				 sizeof(struct udphdr);
1394 
1395 		if (hlen + min(datalen, cork->gso_size) > cork->fragsize) {
1396 			kfree_skb(skb);
1397 			return -EMSGSIZE;
1398 		}
1399 		if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
1400 			kfree_skb(skb);
1401 			return -EINVAL;
1402 		}
1403 		if (udp_get_no_check6_tx(sk)) {
1404 			kfree_skb(skb);
1405 			return -EINVAL;
1406 		}
1407 		if (dst_xfrm(skb_dst(skb))) {
1408 			kfree_skb(skb);
1409 			return -EIO;
1410 		}
1411 
1412 		if (datalen > cork->gso_size) {
1413 			skb_shinfo(skb)->gso_size = cork->gso_size;
1414 			skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
1415 			skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen,
1416 								 cork->gso_size);
1417 
1418 			/* Don't checksum the payload, skb will get segmented */
1419 			goto csum_partial;
1420 		}
1421 	}
1422 
1423 	if (udp_get_no_check6_tx(sk)) {   /* UDP csum disabled */
1424 		skb->ip_summed = CHECKSUM_NONE;
1425 		goto send;
1426 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
1427 csum_partial:
1428 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
1429 		goto send;
1430 	}
1431 
1432 	/* add protocol-dependent pseudo-header */
1433 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
1434 				    len, IPPROTO_UDP, udp_csum(skb));
1435 	if (uh->check == 0)
1436 		uh->check = CSUM_MANGLED_0;
1437 
1438 send:
1439 	err = ip6_send_skb(skb);
1440 	if (unlikely(err)) {
1441 		if (err == -ENOBUFS && !inet6_test_bit(RECVERR6, sk)) {
1442 			UDP6_INC_STATS(sock_net(sk), UDP_MIB_SNDBUFERRORS);
1443 			err = 0;
1444 		}
1445 	} else {
1446 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_OUTDATAGRAMS);
1447 	}
1448 	return err;
1449 }
1450 
1451 static int udp_v6_push_pending_frames(struct sock *sk)
1452 {
1453 	struct sk_buff *skb;
1454 	struct udp_sock  *up = udp_sk(sk);
1455 	int err = 0;
1456 
1457 	if (up->pending == AF_INET)
1458 		return udp_push_pending_frames(sk);
1459 
1460 	skb = ip6_finish_skb(sk);
1461 	if (!skb)
1462 		goto out;
1463 
1464 	err = udp_v6_send_skb(skb, &inet_sk(sk)->cork.fl.u.ip6,
1465 			      &inet_sk(sk)->cork.base);
1466 out:
1467 	up->len = 0;
1468 	WRITE_ONCE(up->pending, 0);
1469 	return err;
1470 }
1471 
1472 int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1473 {
1474 	int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
1475 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
1476 	struct ipv6_txoptions *opt_to_free = NULL;
1477 	struct in6_addr *daddr, *final_p, final;
1478 	struct ip6_flowlabel *flowlabel = NULL;
1479 	struct inet_sock *inet = inet_sk(sk);
1480 	struct ipv6_pinfo *np = inet6_sk(sk);
1481 	struct ipv6_txoptions *opt = NULL;
1482 	struct udp_sock *up = udp_sk(sk);
1483 	struct ipv6_txoptions opt_space;
1484 	int addr_len = msg->msg_namelen;
1485 	struct inet_cork_full cork;
1486 	struct ipcm6_cookie ipc6;
1487 	bool connected = false;
1488 	struct dst_entry *dst;
1489 	struct flowi6 *fl6;
1490 	int ulen = len;
1491 	int err;
1492 
1493 	fl6 = &cork.fl.u.ip6;
1494 	ipcm6_init_sk(&ipc6, sk);
1495 	ipc6.gso_size = READ_ONCE(up->gso_size);
1496 
1497 	/* destination address check */
1498 	if (sin6) {
1499 		if (addr_len < offsetof(struct sockaddr, sa_data))
1500 			return -EINVAL;
1501 
1502 		switch (sin6->sin6_family) {
1503 		case AF_INET6:
1504 			if (addr_len < SIN6_LEN_RFC2133)
1505 				return -EINVAL;
1506 			daddr = &sin6->sin6_addr;
1507 			if (ipv6_addr_any(daddr) &&
1508 			    ipv6_addr_v4mapped(&np->saddr))
1509 				ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
1510 						       daddr);
1511 			break;
1512 		case AF_INET:
1513 			goto do_udp_sendmsg;
1514 		case AF_UNSPEC:
1515 			msg->msg_name = sin6 = NULL;
1516 			msg->msg_namelen = addr_len = 0;
1517 			daddr = NULL;
1518 			break;
1519 		default:
1520 			return -EINVAL;
1521 		}
1522 	} else if (!READ_ONCE(up->pending)) {
1523 		if (sk->sk_state != TCP_ESTABLISHED)
1524 			return -EDESTADDRREQ;
1525 		daddr = &sk->sk_v6_daddr;
1526 	} else
1527 		daddr = NULL;
1528 
1529 	if (daddr) {
1530 		if (ipv6_addr_v4mapped(daddr)) {
1531 			struct sockaddr_in sin;
1532 			sin.sin_family = AF_INET;
1533 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1534 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
1535 			msg->msg_name = &sin;
1536 			msg->msg_namelen = sizeof(sin);
1537 do_udp_sendmsg:
1538 			err = ipv6_only_sock(sk) ?
1539 				-ENETUNREACH : udp_sendmsg(sk, msg, len);
1540 			msg->msg_name = sin6;
1541 			msg->msg_namelen = addr_len;
1542 			return err;
1543 		}
1544 	}
1545 
1546 	/* Rough check on arithmetic overflow,
1547 	   better check is made in ip6_append_data().
1548 	   */
1549 	if (len > INT_MAX - sizeof(struct udphdr))
1550 		return -EMSGSIZE;
1551 
1552 	if (READ_ONCE(up->pending)) {
1553 		if (READ_ONCE(up->pending) == AF_INET)
1554 			return udp_sendmsg(sk, msg, len);
1555 		/*
1556 		 * There are pending frames.
1557 		 * The socket lock must be held while it's corked.
1558 		 */
1559 		lock_sock(sk);
1560 		if (likely(up->pending)) {
1561 			if (unlikely(up->pending != AF_INET6)) {
1562 				release_sock(sk);
1563 				return -EAFNOSUPPORT;
1564 			}
1565 			dst = NULL;
1566 			goto do_append_data;
1567 		}
1568 		release_sock(sk);
1569 	}
1570 	ulen += sizeof(struct udphdr);
1571 
1572 	memset(fl6, 0, sizeof(*fl6));
1573 
1574 	if (sin6) {
1575 		if (sin6->sin6_port == 0)
1576 			return -EINVAL;
1577 
1578 		fl6->fl6_dport = sin6->sin6_port;
1579 		daddr = &sin6->sin6_addr;
1580 
1581 		if (inet6_test_bit(SNDFLOW, sk)) {
1582 			fl6->flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1583 			if (fl6->flowlabel & IPV6_FLOWLABEL_MASK) {
1584 				flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
1585 				if (IS_ERR(flowlabel))
1586 					return -EINVAL;
1587 			}
1588 		}
1589 
1590 		/*
1591 		 * Otherwise it will be difficult to maintain
1592 		 * sk->sk_dst_cache.
1593 		 */
1594 		if (sk->sk_state == TCP_ESTABLISHED &&
1595 		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
1596 			daddr = &sk->sk_v6_daddr;
1597 
1598 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1599 		    sin6->sin6_scope_id &&
1600 		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
1601 			fl6->flowi6_oif = sin6->sin6_scope_id;
1602 	} else {
1603 		if (sk->sk_state != TCP_ESTABLISHED)
1604 			return -EDESTADDRREQ;
1605 
1606 		fl6->fl6_dport = inet->inet_dport;
1607 		daddr = &sk->sk_v6_daddr;
1608 		fl6->flowlabel = np->flow_label;
1609 		connected = true;
1610 	}
1611 
1612 	if (!fl6->flowi6_oif)
1613 		fl6->flowi6_oif = READ_ONCE(sk->sk_bound_dev_if);
1614 
1615 	if (!fl6->flowi6_oif)
1616 		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1617 
1618 	fl6->flowi6_uid = sk_uid(sk);
1619 
1620 	if (msg->msg_controllen) {
1621 		opt = &opt_space;
1622 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1623 		opt->tot_len = sizeof(*opt);
1624 		ipc6.opt = opt;
1625 
1626 		err = udp_cmsg_send(sk, msg, &ipc6.gso_size);
1627 		if (err > 0) {
1628 			err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, fl6,
1629 						    &ipc6);
1630 			connected = false;
1631 		}
1632 		if (err < 0) {
1633 			fl6_sock_release(flowlabel);
1634 			return err;
1635 		}
1636 		if ((fl6->flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1637 			flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
1638 			if (IS_ERR(flowlabel))
1639 				return -EINVAL;
1640 		}
1641 		if (!(opt->opt_nflen|opt->opt_flen))
1642 			opt = NULL;
1643 	}
1644 	if (!opt) {
1645 		opt = txopt_get(np);
1646 		opt_to_free = opt;
1647 	}
1648 	if (flowlabel)
1649 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1650 	opt = ipv6_fixup_options(&opt_space, opt);
1651 	ipc6.opt = opt;
1652 
1653 	fl6->flowi6_proto = IPPROTO_UDP;
1654 	fl6->flowi6_mark = ipc6.sockc.mark;
1655 	fl6->daddr = *daddr;
1656 	if (ipv6_addr_any(&fl6->saddr) && !ipv6_addr_any(&np->saddr))
1657 		fl6->saddr = np->saddr;
1658 	fl6->fl6_sport = inet->inet_sport;
1659 
1660 	if (cgroup_bpf_enabled(CGROUP_UDP6_SENDMSG) && !connected) {
1661 		err = BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk,
1662 					   (struct sockaddr *)sin6,
1663 					   &addr_len,
1664 					   &fl6->saddr);
1665 		if (err)
1666 			goto out_no_dst;
1667 		if (sin6) {
1668 			if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
1669 				/* BPF program rewrote IPv6-only by IPv4-mapped
1670 				 * IPv6. It's currently unsupported.
1671 				 */
1672 				err = -ENOTSUPP;
1673 				goto out_no_dst;
1674 			}
1675 			if (sin6->sin6_port == 0) {
1676 				/* BPF program set invalid port. Reject it. */
1677 				err = -EINVAL;
1678 				goto out_no_dst;
1679 			}
1680 			fl6->fl6_dport = sin6->sin6_port;
1681 			fl6->daddr = sin6->sin6_addr;
1682 		}
1683 	}
1684 
1685 	if (ipv6_addr_any(&fl6->daddr))
1686 		fl6->daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1687 
1688 	final_p = fl6_update_dst(fl6, opt, &final);
1689 	if (final_p)
1690 		connected = false;
1691 
1692 	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr)) {
1693 		fl6->flowi6_oif = READ_ONCE(np->mcast_oif);
1694 		connected = false;
1695 	} else if (!fl6->flowi6_oif)
1696 		fl6->flowi6_oif = READ_ONCE(np->ucast_oif);
1697 
1698 	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
1699 
1700 	fl6->flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6->flowlabel);
1701 
1702 	dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p, connected);
1703 	if (IS_ERR(dst)) {
1704 		err = PTR_ERR(dst);
1705 		dst = NULL;
1706 		goto out;
1707 	}
1708 
1709 	if (ipc6.hlimit < 0)
1710 		ipc6.hlimit = ip6_sk_dst_hoplimit(np, fl6, dst);
1711 
1712 	if (msg->msg_flags&MSG_CONFIRM)
1713 		goto do_confirm;
1714 back_from_confirm:
1715 
1716 	/* Lockless fast path for the non-corking case */
1717 	if (!corkreq) {
1718 		struct sk_buff *skb;
1719 
1720 		skb = ip6_make_skb(sk, ip_generic_getfrag, msg, ulen,
1721 				   sizeof(struct udphdr), &ipc6,
1722 				   dst_rt6_info(dst),
1723 				   msg->msg_flags, &cork);
1724 		err = PTR_ERR(skb);
1725 		if (!IS_ERR_OR_NULL(skb))
1726 			err = udp_v6_send_skb(skb, fl6, &cork.base);
1727 		/* ip6_make_skb steals dst reference */
1728 		goto out_no_dst;
1729 	}
1730 
1731 	lock_sock(sk);
1732 	if (unlikely(up->pending)) {
1733 		/* The socket is already corked while preparing it. */
1734 		/* ... which is an evident application bug. --ANK */
1735 		release_sock(sk);
1736 
1737 		net_dbg_ratelimited("udp cork app bug 2\n");
1738 		err = -EINVAL;
1739 		goto out;
1740 	}
1741 
1742 	WRITE_ONCE(up->pending, AF_INET6);
1743 
1744 do_append_data:
1745 	up->len += ulen;
1746 	err = ip6_append_data(sk, ip_generic_getfrag, msg, ulen,
1747 			      sizeof(struct udphdr), &ipc6, fl6,
1748 			      dst_rt6_info(dst),
1749 			      corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1750 	if (err)
1751 		udp_v6_flush_pending_frames(sk);
1752 	else if (!corkreq)
1753 		err = udp_v6_push_pending_frames(sk);
1754 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1755 		WRITE_ONCE(up->pending, 0);
1756 
1757 	if (err > 0)
1758 		err = inet6_test_bit(RECVERR6, sk) ? net_xmit_errno(err) : 0;
1759 	release_sock(sk);
1760 
1761 out:
1762 	dst_release(dst);
1763 out_no_dst:
1764 	fl6_sock_release(flowlabel);
1765 	txopt_put(opt_to_free);
1766 	if (!err)
1767 		return len;
1768 	/*
1769 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1770 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1771 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1772 	 * things).  We could add another new stat but at least for now that
1773 	 * seems like overkill.
1774 	 */
1775 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
1776 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_SNDBUFERRORS);
1777 
1778 	return err;
1779 
1780 do_confirm:
1781 	if (msg->msg_flags & MSG_PROBE)
1782 		dst_confirm_neigh(dst, &fl6->daddr);
1783 	if (!(msg->msg_flags&MSG_PROBE) || len)
1784 		goto back_from_confirm;
1785 	err = 0;
1786 	goto out;
1787 }
1788 EXPORT_SYMBOL(udpv6_sendmsg);
1789 
1790 static void udpv6_splice_eof(struct socket *sock)
1791 {
1792 	struct sock *sk = sock->sk;
1793 	struct udp_sock *up = udp_sk(sk);
1794 
1795 	if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk))
1796 		return;
1797 
1798 	lock_sock(sk);
1799 	if (up->pending && !udp_test_bit(CORK, sk))
1800 		udp_v6_push_pending_frames(sk);
1801 	release_sock(sk);
1802 }
1803 
1804 static void udpv6_destroy_sock(struct sock *sk)
1805 {
1806 	struct udp_sock *up = udp_sk(sk);
1807 	lock_sock(sk);
1808 
1809 	/* protects from races with udp_abort() */
1810 	sock_set_flag(sk, SOCK_DEAD);
1811 	udp_v6_flush_pending_frames(sk);
1812 	release_sock(sk);
1813 
1814 	if (static_branch_unlikely(&udpv6_encap_needed_key)) {
1815 		if (up->encap_type) {
1816 			void (*encap_destroy)(struct sock *sk);
1817 			encap_destroy = READ_ONCE(up->encap_destroy);
1818 			if (encap_destroy)
1819 				encap_destroy(sk);
1820 		}
1821 		if (udp_test_bit(ENCAP_ENABLED, sk)) {
1822 			static_branch_dec(&udpv6_encap_needed_key);
1823 			udp_encap_disable();
1824 			udp_tunnel_cleanup_gro(sk);
1825 		}
1826 	}
1827 }
1828 
1829 /*
1830  *	Socket option code for UDP
1831  */
1832 static int udpv6_setsockopt(struct sock *sk, int level, int optname,
1833 			    sockptr_t optval, unsigned int optlen)
1834 {
1835 	if (level == SOL_UDP || level == SOL_SOCKET)
1836 		return udp_lib_setsockopt(sk, level, optname,
1837 					  optval, optlen,
1838 					  udp_v6_push_pending_frames);
1839 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1840 }
1841 
1842 static int udpv6_getsockopt(struct sock *sk, int level, int optname,
1843 			    char __user *optval, int __user *optlen)
1844 {
1845 	sockopt_t opt;
1846 	int err;
1847 
1848 	if (level != SOL_UDP)
1849 		return ipv6_getsockopt(sk, level, optname, optval, optlen);
1850 
1851 	err = sockopt_init_user(&opt, optval, optlen);
1852 	if (err)
1853 		return err;
1854 
1855 	err = udp_lib_getsockopt(sk, level, optname, &opt);
1856 	if (err)
1857 		return err;
1858 	if (put_user(opt.optlen, optlen))
1859 		return -EFAULT;
1860 	return 0;
1861 }
1862 
1863 
1864 /* ------------------------------------------------------------------------ */
1865 #ifdef CONFIG_PROC_FS
1866 static int udp6_seq_show(struct seq_file *seq, void *v)
1867 {
1868 	if (v == SEQ_START_TOKEN) {
1869 		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1870 	} else {
1871 		int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1872 		const struct inet_sock *inet = inet_sk((const struct sock *)v);
1873 		__u16 srcp = ntohs(inet->inet_sport);
1874 		__u16 destp = ntohs(inet->inet_dport);
1875 		__ip6_dgram_sock_seq_show(seq, v, srcp, destp,
1876 					  udp_rqueue_get(v), bucket);
1877 	}
1878 	return 0;
1879 }
1880 
1881 static const struct seq_operations udp6_seq_ops = {
1882 	.start		= udp_seq_start,
1883 	.next		= udp_seq_next,
1884 	.stop		= udp_seq_stop,
1885 	.show		= udp6_seq_show,
1886 };
1887 
1888 static struct udp_seq_afinfo udp6_seq_afinfo = {
1889 	.family		= AF_INET6,
1890 };
1891 
1892 int __net_init udp6_proc_init(struct net *net)
1893 {
1894 	if (!proc_create_net_data("udp6", 0444, net->proc_net, &udp6_seq_ops,
1895 			sizeof(struct udp_iter_state), &udp6_seq_afinfo))
1896 		return -ENOMEM;
1897 	return 0;
1898 }
1899 
1900 void udp6_proc_exit(struct net *net)
1901 {
1902 	remove_proc_entry("udp6", net->proc_net);
1903 }
1904 #endif /* CONFIG_PROC_FS */
1905 
1906 /* ------------------------------------------------------------------------ */
1907 
1908 struct proto udpv6_prot = {
1909 	.name			= "UDPv6",
1910 	.owner			= THIS_MODULE,
1911 	.close			= udp_lib_close,
1912 	.pre_connect		= udpv6_pre_connect,
1913 	.connect		= udpv6_connect,
1914 	.disconnect		= udp_disconnect,
1915 	.ioctl			= udp_ioctl,
1916 	.init			= udpv6_init_sock,
1917 	.destroy		= udpv6_destroy_sock,
1918 	.setsockopt		= udpv6_setsockopt,
1919 	.getsockopt		= udpv6_getsockopt,
1920 	.sendmsg		= udpv6_sendmsg,
1921 	.recvmsg		= udpv6_recvmsg,
1922 	.splice_eof		= udpv6_splice_eof,
1923 	.release_cb		= ip6_datagram_release_cb,
1924 	.hash			= udp_lib_hash,
1925 	.unhash			= udp_lib_unhash,
1926 	.rehash			= udp_v6_rehash,
1927 	.get_port		= udp_v6_get_port,
1928 	.put_port		= udp_lib_unhash,
1929 #ifdef CONFIG_BPF_SYSCALL
1930 	.psock_update_sk_prot	= udp_bpf_update_proto,
1931 #endif
1932 
1933 	.memory_allocated	= &net_aligned_data.udp_memory_allocated,
1934 	.per_cpu_fw_alloc	= &udp_memory_per_cpu_fw_alloc,
1935 
1936 	.sysctl_mem		= sysctl_udp_mem,
1937 	.sysctl_wmem_offset     = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
1938 	.sysctl_rmem_offset     = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
1939 	.obj_size		= sizeof(struct udp6_sock),
1940 	.ipv6_pinfo_offset = offsetof(struct udp6_sock, inet6),
1941 	.diag_destroy		= udp_abort,
1942 };
1943 
1944 static struct inet_protosw udpv6_protosw = {
1945 	.type =      SOCK_DGRAM,
1946 	.protocol =  IPPROTO_UDP,
1947 	.prot =      &udpv6_prot,
1948 	.ops =       &inet6_dgram_ops,
1949 	.flags =     INET_PROTOSW_PERMANENT,
1950 };
1951 
1952 int __init udpv6_init(void)
1953 {
1954 	int ret;
1955 
1956 	net_hotdata.udpv6_protocol = (struct inet6_protocol) {
1957 		.handler     = udpv6_rcv,
1958 		.err_handler = udpv6_err,
1959 		.flags	     = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
1960 	};
1961 	ret = inet6_add_protocol(&net_hotdata.udpv6_protocol, IPPROTO_UDP);
1962 	if (ret)
1963 		goto out;
1964 
1965 	ret = inet6_register_protosw(&udpv6_protosw);
1966 	if (ret)
1967 		goto out_udpv6_protocol;
1968 out:
1969 	return ret;
1970 
1971 out_udpv6_protocol:
1972 	inet6_del_protocol(&net_hotdata.udpv6_protocol, IPPROTO_UDP);
1973 	goto out;
1974 }
1975 
1976 void udpv6_exit(void)
1977 {
1978 	inet6_unregister_protosw(&udpv6_protosw);
1979 	inet6_del_protocol(&net_hotdata.udpv6_protocol, IPPROTO_UDP);
1980 }
1981