xref: /openbmc/linux/net/ipv6/udp.c (revision 4f6cce39)
1 /*
2  *	UDP over IPv6
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	Based on linux/ipv4/udp.c
9  *
10  *	Fixes:
11  *	Hideaki YOSHIFUJI	:	sin6_scope_id support
12  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
13  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
14  *					a single port at the same time.
15  *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
16  *      YOSHIFUJI Hideaki @USAGI:	convert /proc/net/udp6 to seq_file.
17  *
18  *	This program is free software; you can redistribute it and/or
19  *      modify it under the terms of the GNU General Public License
20  *      as published by the Free Software Foundation; either version
21  *      2 of the License, or (at your option) any later version.
22  */
23 
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/in6.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/ipv6.h>
33 #include <linux/icmpv6.h>
34 #include <linux/init.h>
35 #include <linux/module.h>
36 #include <linux/skbuff.h>
37 #include <linux/slab.h>
38 #include <linux/uaccess.h>
39 
40 #include <net/addrconf.h>
41 #include <net/ndisc.h>
42 #include <net/protocol.h>
43 #include <net/transp_v6.h>
44 #include <net/ip6_route.h>
45 #include <net/raw.h>
46 #include <net/tcp_states.h>
47 #include <net/ip6_checksum.h>
48 #include <net/xfrm.h>
49 #include <net/inet6_hashtables.h>
50 #include <net/busy_poll.h>
51 #include <net/sock_reuseport.h>
52 
53 #include <linux/proc_fs.h>
54 #include <linux/seq_file.h>
55 #include <trace/events/skb.h>
56 #include "udp_impl.h"
57 
58 static bool udp6_lib_exact_dif_match(struct net *net, struct sk_buff *skb)
59 {
60 #if defined(CONFIG_NET_L3_MASTER_DEV)
61 	if (!net->ipv4.sysctl_udp_l3mdev_accept &&
62 	    skb && ipv6_l3mdev_skb(IP6CB(skb)->flags))
63 		return true;
64 #endif
65 	return false;
66 }
67 
68 static u32 udp6_ehashfn(const struct net *net,
69 			const struct in6_addr *laddr,
70 			const u16 lport,
71 			const struct in6_addr *faddr,
72 			const __be16 fport)
73 {
74 	static u32 udp6_ehash_secret __read_mostly;
75 	static u32 udp_ipv6_hash_secret __read_mostly;
76 
77 	u32 lhash, fhash;
78 
79 	net_get_random_once(&udp6_ehash_secret,
80 			    sizeof(udp6_ehash_secret));
81 	net_get_random_once(&udp_ipv6_hash_secret,
82 			    sizeof(udp_ipv6_hash_secret));
83 
84 	lhash = (__force u32)laddr->s6_addr32[3];
85 	fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
86 
87 	return __inet6_ehashfn(lhash, lport, fhash, fport,
88 			       udp_ipv6_hash_secret + net_hash_mix(net));
89 }
90 
91 static u32 udp6_portaddr_hash(const struct net *net,
92 			      const struct in6_addr *addr6,
93 			      unsigned int port)
94 {
95 	unsigned int hash, mix = net_hash_mix(net);
96 
97 	if (ipv6_addr_any(addr6))
98 		hash = jhash_1word(0, mix);
99 	else if (ipv6_addr_v4mapped(addr6))
100 		hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
101 	else
102 		hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);
103 
104 	return hash ^ port;
105 }
106 
107 int udp_v6_get_port(struct sock *sk, unsigned short snum)
108 {
109 	unsigned int hash2_nulladdr =
110 		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
111 	unsigned int hash2_partial =
112 		udp6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
113 
114 	/* precompute partial secondary hash */
115 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
116 	return udp_lib_get_port(sk, snum, hash2_nulladdr);
117 }
118 
119 static void udp_v6_rehash(struct sock *sk)
120 {
121 	u16 new_hash = udp6_portaddr_hash(sock_net(sk),
122 					  &sk->sk_v6_rcv_saddr,
123 					  inet_sk(sk)->inet_num);
124 
125 	udp_lib_rehash(sk, new_hash);
126 }
127 
128 static int compute_score(struct sock *sk, struct net *net,
129 			 const struct in6_addr *saddr, __be16 sport,
130 			 const struct in6_addr *daddr, unsigned short hnum,
131 			 int dif, bool exact_dif)
132 {
133 	int score;
134 	struct inet_sock *inet;
135 
136 	if (!net_eq(sock_net(sk), net) ||
137 	    udp_sk(sk)->udp_port_hash != hnum ||
138 	    sk->sk_family != PF_INET6)
139 		return -1;
140 
141 	score = 0;
142 	inet = inet_sk(sk);
143 
144 	if (inet->inet_dport) {
145 		if (inet->inet_dport != sport)
146 			return -1;
147 		score++;
148 	}
149 
150 	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
151 		if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
152 			return -1;
153 		score++;
154 	}
155 
156 	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
157 		if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
158 			return -1;
159 		score++;
160 	}
161 
162 	if (sk->sk_bound_dev_if || exact_dif) {
163 		if (sk->sk_bound_dev_if != dif)
164 			return -1;
165 		score++;
166 	}
167 
168 	if (sk->sk_incoming_cpu == raw_smp_processor_id())
169 		score++;
170 
171 	return score;
172 }
173 
174 /* called with rcu_read_lock() */
175 static struct sock *udp6_lib_lookup2(struct net *net,
176 		const struct in6_addr *saddr, __be16 sport,
177 		const struct in6_addr *daddr, unsigned int hnum, int dif,
178 		bool exact_dif, struct udp_hslot *hslot2,
179 		struct sk_buff *skb)
180 {
181 	struct sock *sk, *result;
182 	int score, badness, matches = 0, reuseport = 0;
183 	u32 hash = 0;
184 
185 	result = NULL;
186 	badness = -1;
187 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
188 		score = compute_score(sk, net, saddr, sport,
189 				      daddr, hnum, dif, exact_dif);
190 		if (score > badness) {
191 			reuseport = sk->sk_reuseport;
192 			if (reuseport) {
193 				hash = udp6_ehashfn(net, daddr, hnum,
194 						    saddr, sport);
195 
196 				result = reuseport_select_sock(sk, hash, skb,
197 							sizeof(struct udphdr));
198 				if (result)
199 					return result;
200 				matches = 1;
201 			}
202 			result = sk;
203 			badness = score;
204 		} else if (score == badness && reuseport) {
205 			matches++;
206 			if (reciprocal_scale(hash, matches) == 0)
207 				result = sk;
208 			hash = next_pseudo_random32(hash);
209 		}
210 	}
211 	return result;
212 }
213 
214 /* rcu_read_lock() must be held */
215 struct sock *__udp6_lib_lookup(struct net *net,
216 				      const struct in6_addr *saddr, __be16 sport,
217 				      const struct in6_addr *daddr, __be16 dport,
218 				      int dif, struct udp_table *udptable,
219 				      struct sk_buff *skb)
220 {
221 	struct sock *sk, *result;
222 	unsigned short hnum = ntohs(dport);
223 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
224 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
225 	bool exact_dif = udp6_lib_exact_dif_match(net, skb);
226 	int score, badness, matches = 0, reuseport = 0;
227 	u32 hash = 0;
228 
229 	if (hslot->count > 10) {
230 		hash2 = udp6_portaddr_hash(net, daddr, hnum);
231 		slot2 = hash2 & udptable->mask;
232 		hslot2 = &udptable->hash2[slot2];
233 		if (hslot->count < hslot2->count)
234 			goto begin;
235 
236 		result = udp6_lib_lookup2(net, saddr, sport,
237 					  daddr, hnum, dif, exact_dif,
238 					  hslot2, skb);
239 		if (!result) {
240 			unsigned int old_slot2 = slot2;
241 			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
242 			slot2 = hash2 & udptable->mask;
243 			/* avoid searching the same slot again. */
244 			if (unlikely(slot2 == old_slot2))
245 				return result;
246 
247 			hslot2 = &udptable->hash2[slot2];
248 			if (hslot->count < hslot2->count)
249 				goto begin;
250 
251 			result = udp6_lib_lookup2(net, saddr, sport,
252 						  daddr, hnum, dif,
253 						  exact_dif, hslot2,
254 						  skb);
255 		}
256 		return result;
257 	}
258 begin:
259 	result = NULL;
260 	badness = -1;
261 	sk_for_each_rcu(sk, &hslot->head) {
262 		score = compute_score(sk, net, saddr, sport, daddr, hnum, dif,
263 				      exact_dif);
264 		if (score > badness) {
265 			reuseport = sk->sk_reuseport;
266 			if (reuseport) {
267 				hash = udp6_ehashfn(net, daddr, hnum,
268 						    saddr, sport);
269 				result = reuseport_select_sock(sk, hash, skb,
270 							sizeof(struct udphdr));
271 				if (result)
272 					return result;
273 				matches = 1;
274 			}
275 			result = sk;
276 			badness = score;
277 		} else if (score == badness && reuseport) {
278 			matches++;
279 			if (reciprocal_scale(hash, matches) == 0)
280 				result = sk;
281 			hash = next_pseudo_random32(hash);
282 		}
283 	}
284 	return result;
285 }
286 EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
287 
288 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
289 					  __be16 sport, __be16 dport,
290 					  struct udp_table *udptable)
291 {
292 	const struct ipv6hdr *iph = ipv6_hdr(skb);
293 	struct sock *sk;
294 
295 	sk = skb_steal_sock(skb);
296 	if (unlikely(sk))
297 		return sk;
298 	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
299 				 &iph->daddr, dport, inet6_iif(skb),
300 				 udptable, skb);
301 }
302 
303 struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
304 				 __be16 sport, __be16 dport)
305 {
306 	const struct ipv6hdr *iph = ipv6_hdr(skb);
307 
308 	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
309 				 &iph->daddr, dport, inet6_iif(skb),
310 				 &udp_table, skb);
311 }
312 EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);
313 
314 /* Must be called under rcu_read_lock().
315  * Does increment socket refcount.
316  */
317 #if IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_SOCKET) || \
318     IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TPROXY) || \
319     IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
320 struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
321 			     const struct in6_addr *daddr, __be16 dport, int dif)
322 {
323 	struct sock *sk;
324 
325 	sk =  __udp6_lib_lookup(net, saddr, sport, daddr, dport,
326 				dif, &udp_table, NULL);
327 	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
328 		sk = NULL;
329 	return sk;
330 }
331 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
332 #endif
333 
334 /*
335  *	This should be easy, if there is something there we
336  *	return it, otherwise we block.
337  */
338 
339 int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
340 		  int noblock, int flags, int *addr_len)
341 {
342 	struct ipv6_pinfo *np = inet6_sk(sk);
343 	struct inet_sock *inet = inet_sk(sk);
344 	struct sk_buff *skb;
345 	unsigned int ulen, copied;
346 	int peeked, peeking, off;
347 	int err;
348 	int is_udplite = IS_UDPLITE(sk);
349 	bool checksum_valid = false;
350 	int is_udp4;
351 
352 	if (flags & MSG_ERRQUEUE)
353 		return ipv6_recv_error(sk, msg, len, addr_len);
354 
355 	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
356 		return ipv6_recv_rxpmtu(sk, msg, len, addr_len);
357 
358 try_again:
359 	peeking = off = sk_peek_offset(sk, flags);
360 	skb = __skb_recv_udp(sk, flags, noblock, &peeked, &off, &err);
361 	if (!skb)
362 		return err;
363 
364 	ulen = skb->len;
365 	copied = len;
366 	if (copied > ulen - off)
367 		copied = ulen - off;
368 	else if (copied < ulen)
369 		msg->msg_flags |= MSG_TRUNC;
370 
371 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
372 
373 	/*
374 	 * If checksum is needed at all, try to do it while copying the
375 	 * data.  If the data is truncated, or if we only want a partial
376 	 * coverage checksum (UDP-Lite), do it before the copy.
377 	 */
378 
379 	if (copied < ulen || peeking ||
380 	    (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
381 		checksum_valid = !udp_lib_checksum_complete(skb);
382 		if (!checksum_valid)
383 			goto csum_copy_err;
384 	}
385 
386 	if (checksum_valid || skb_csum_unnecessary(skb))
387 		err = skb_copy_datagram_msg(skb, off, msg, copied);
388 	else {
389 		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
390 		if (err == -EINVAL)
391 			goto csum_copy_err;
392 	}
393 	if (unlikely(err)) {
394 		if (!peeked) {
395 			atomic_inc(&sk->sk_drops);
396 			if (is_udp4)
397 				UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
398 					      is_udplite);
399 			else
400 				UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
401 					       is_udplite);
402 		}
403 		kfree_skb(skb);
404 		return err;
405 	}
406 	if (!peeked) {
407 		if (is_udp4)
408 			UDP_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
409 				      is_udplite);
410 		else
411 			UDP6_INC_STATS(sock_net(sk), UDP_MIB_INDATAGRAMS,
412 				       is_udplite);
413 	}
414 
415 	sock_recv_ts_and_drops(msg, sk, skb);
416 
417 	/* Copy the address. */
418 	if (msg->msg_name) {
419 		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
420 		sin6->sin6_family = AF_INET6;
421 		sin6->sin6_port = udp_hdr(skb)->source;
422 		sin6->sin6_flowinfo = 0;
423 
424 		if (is_udp4) {
425 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
426 					       &sin6->sin6_addr);
427 			sin6->sin6_scope_id = 0;
428 		} else {
429 			sin6->sin6_addr = ipv6_hdr(skb)->saddr;
430 			sin6->sin6_scope_id =
431 				ipv6_iface_scope_id(&sin6->sin6_addr,
432 						    inet6_iif(skb));
433 		}
434 		*addr_len = sizeof(*sin6);
435 	}
436 
437 	if (np->rxopt.all)
438 		ip6_datagram_recv_common_ctl(sk, msg, skb);
439 
440 	if (is_udp4) {
441 		if (inet->cmsg_flags)
442 			ip_cmsg_recv_offset(msg, sk, skb,
443 					    sizeof(struct udphdr), off);
444 	} else {
445 		if (np->rxopt.all)
446 			ip6_datagram_recv_specific_ctl(sk, msg, skb);
447 	}
448 
449 	err = copied;
450 	if (flags & MSG_TRUNC)
451 		err = ulen;
452 
453 	skb_consume_udp(sk, skb, peeking ? -err : err);
454 	return err;
455 
456 csum_copy_err:
457 	if (!__sk_queue_drop_skb(sk, skb, flags, udp_skb_destructor)) {
458 		if (is_udp4) {
459 			UDP_INC_STATS(sock_net(sk),
460 				      UDP_MIB_CSUMERRORS, is_udplite);
461 			UDP_INC_STATS(sock_net(sk),
462 				      UDP_MIB_INERRORS, is_udplite);
463 		} else {
464 			UDP6_INC_STATS(sock_net(sk),
465 				       UDP_MIB_CSUMERRORS, is_udplite);
466 			UDP6_INC_STATS(sock_net(sk),
467 				       UDP_MIB_INERRORS, is_udplite);
468 		}
469 	}
470 	kfree_skb(skb);
471 
472 	/* starting over for a new packet, but check if we need to yield */
473 	cond_resched();
474 	msg->msg_flags &= ~MSG_TRUNC;
475 	goto try_again;
476 }
477 
478 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
479 		    u8 type, u8 code, int offset, __be32 info,
480 		    struct udp_table *udptable)
481 {
482 	struct ipv6_pinfo *np;
483 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
484 	const struct in6_addr *saddr = &hdr->saddr;
485 	const struct in6_addr *daddr = &hdr->daddr;
486 	struct udphdr *uh = (struct udphdr *)(skb->data+offset);
487 	struct sock *sk;
488 	int harderr;
489 	int err;
490 	struct net *net = dev_net(skb->dev);
491 
492 	sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
493 			       inet6_iif(skb), udptable, skb);
494 	if (!sk) {
495 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
496 				  ICMP6_MIB_INERRORS);
497 		return;
498 	}
499 
500 	harderr = icmpv6_err_convert(type, code, &err);
501 	np = inet6_sk(sk);
502 
503 	if (type == ICMPV6_PKT_TOOBIG) {
504 		if (!ip6_sk_accept_pmtu(sk))
505 			goto out;
506 		ip6_sk_update_pmtu(skb, sk, info);
507 		if (np->pmtudisc != IPV6_PMTUDISC_DONT)
508 			harderr = 1;
509 	}
510 	if (type == NDISC_REDIRECT) {
511 		ip6_sk_redirect(skb, sk);
512 		goto out;
513 	}
514 
515 	if (!np->recverr) {
516 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
517 			goto out;
518 	} else {
519 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
520 	}
521 
522 	sk->sk_err = err;
523 	sk->sk_error_report(sk);
524 out:
525 	return;
526 }
527 
528 int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
529 {
530 	int rc;
531 
532 	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
533 		sock_rps_save_rxhash(sk, skb);
534 		sk_mark_napi_id(sk, skb);
535 		sk_incoming_cpu_update(sk);
536 	} else {
537 		sk_mark_napi_id_once(sk, skb);
538 	}
539 
540 	rc = __udp_enqueue_schedule_skb(sk, skb);
541 	if (rc < 0) {
542 		int is_udplite = IS_UDPLITE(sk);
543 
544 		/* Note that an ENOMEM error is charged twice */
545 		if (rc == -ENOMEM)
546 			UDP6_INC_STATS(sock_net(sk),
547 					 UDP_MIB_RCVBUFERRORS, is_udplite);
548 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
549 		kfree_skb(skb);
550 		return -1;
551 	}
552 
553 	return 0;
554 }
555 
556 static __inline__ void udpv6_err(struct sk_buff *skb,
557 				 struct inet6_skb_parm *opt, u8 type,
558 				 u8 code, int offset, __be32 info)
559 {
560 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
561 }
562 
563 static struct static_key udpv6_encap_needed __read_mostly;
564 void udpv6_encap_enable(void)
565 {
566 	if (!static_key_enabled(&udpv6_encap_needed))
567 		static_key_slow_inc(&udpv6_encap_needed);
568 }
569 EXPORT_SYMBOL(udpv6_encap_enable);
570 
571 int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
572 {
573 	struct udp_sock *up = udp_sk(sk);
574 	int is_udplite = IS_UDPLITE(sk);
575 
576 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
577 		goto drop;
578 
579 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
580 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
581 
582 		/*
583 		 * This is an encapsulation socket so pass the skb to
584 		 * the socket's udp_encap_rcv() hook. Otherwise, just
585 		 * fall through and pass this up the UDP socket.
586 		 * up->encap_rcv() returns the following value:
587 		 * =0 if skb was successfully passed to the encap
588 		 *    handler or was discarded by it.
589 		 * >0 if skb should be passed on to UDP.
590 		 * <0 if skb should be resubmitted as proto -N
591 		 */
592 
593 		/* if we're overly short, let UDP handle it */
594 		encap_rcv = ACCESS_ONCE(up->encap_rcv);
595 		if (encap_rcv) {
596 			int ret;
597 
598 			/* Verify checksum before giving to encap */
599 			if (udp_lib_checksum_complete(skb))
600 				goto csum_error;
601 
602 			ret = encap_rcv(sk, skb);
603 			if (ret <= 0) {
604 				__UDP_INC_STATS(sock_net(sk),
605 						UDP_MIB_INDATAGRAMS,
606 						is_udplite);
607 				return -ret;
608 			}
609 		}
610 
611 		/* FALLTHROUGH -- it's a UDP Packet */
612 	}
613 
614 	/*
615 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
616 	 */
617 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
618 
619 		if (up->pcrlen == 0) {          /* full coverage was set  */
620 			net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
621 					    UDP_SKB_CB(skb)->cscov, skb->len);
622 			goto drop;
623 		}
624 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
625 			net_dbg_ratelimited("UDPLITE6: coverage %d too small, need min %d\n",
626 					    UDP_SKB_CB(skb)->cscov, up->pcrlen);
627 			goto drop;
628 		}
629 	}
630 
631 	if (rcu_access_pointer(sk->sk_filter) &&
632 	    udp_lib_checksum_complete(skb))
633 		goto csum_error;
634 
635 	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
636 		goto drop;
637 
638 	udp_csum_pull_header(skb);
639 
640 	skb_dst_drop(skb);
641 
642 	return __udpv6_queue_rcv_skb(sk, skb);
643 
644 csum_error:
645 	__UDP6_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
646 drop:
647 	__UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
648 	atomic_inc(&sk->sk_drops);
649 	kfree_skb(skb);
650 	return -1;
651 }
652 
653 static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
654 				   __be16 loc_port, const struct in6_addr *loc_addr,
655 				   __be16 rmt_port, const struct in6_addr *rmt_addr,
656 				   int dif, unsigned short hnum)
657 {
658 	struct inet_sock *inet = inet_sk(sk);
659 
660 	if (!net_eq(sock_net(sk), net))
661 		return false;
662 
663 	if (udp_sk(sk)->udp_port_hash != hnum ||
664 	    sk->sk_family != PF_INET6 ||
665 	    (inet->inet_dport && inet->inet_dport != rmt_port) ||
666 	    (!ipv6_addr_any(&sk->sk_v6_daddr) &&
667 		    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
668 	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif) ||
669 	    (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
670 		    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
671 		return false;
672 	if (!inet6_mc_check(sk, loc_addr, rmt_addr))
673 		return false;
674 	return true;
675 }
676 
677 static void udp6_csum_zero_error(struct sk_buff *skb)
678 {
679 	/* RFC 2460 section 8.1 says that we SHOULD log
680 	 * this error. Well, it is reasonable.
681 	 */
682 	net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
683 			    &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
684 			    &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
685 }
686 
687 /*
688  * Note: called only from the BH handler context,
689  * so we don't need to lock the hashes.
690  */
691 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
692 		const struct in6_addr *saddr, const struct in6_addr *daddr,
693 		struct udp_table *udptable, int proto)
694 {
695 	struct sock *sk, *first = NULL;
696 	const struct udphdr *uh = udp_hdr(skb);
697 	unsigned short hnum = ntohs(uh->dest);
698 	struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
699 	unsigned int offset = offsetof(typeof(*sk), sk_node);
700 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
701 	int dif = inet6_iif(skb);
702 	struct hlist_node *node;
703 	struct sk_buff *nskb;
704 
705 	if (use_hash2) {
706 		hash2_any = udp6_portaddr_hash(net, &in6addr_any, hnum) &
707 			    udptable->mask;
708 		hash2 = udp6_portaddr_hash(net, daddr, hnum) & udptable->mask;
709 start_lookup:
710 		hslot = &udptable->hash2[hash2];
711 		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
712 	}
713 
714 	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
715 		if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr,
716 					    uh->source, saddr, dif, hnum))
717 			continue;
718 		/* If zero checksum and no_check is not on for
719 		 * the socket then skip it.
720 		 */
721 		if (!uh->check && !udp_sk(sk)->no_check6_rx)
722 			continue;
723 		if (!first) {
724 			first = sk;
725 			continue;
726 		}
727 		nskb = skb_clone(skb, GFP_ATOMIC);
728 		if (unlikely(!nskb)) {
729 			atomic_inc(&sk->sk_drops);
730 			__UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
731 					 IS_UDPLITE(sk));
732 			__UDP6_INC_STATS(net, UDP_MIB_INERRORS,
733 					 IS_UDPLITE(sk));
734 			continue;
735 		}
736 
737 		if (udpv6_queue_rcv_skb(sk, nskb) > 0)
738 			consume_skb(nskb);
739 	}
740 
741 	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
742 	if (use_hash2 && hash2 != hash2_any) {
743 		hash2 = hash2_any;
744 		goto start_lookup;
745 	}
746 
747 	if (first) {
748 		if (udpv6_queue_rcv_skb(first, skb) > 0)
749 			consume_skb(skb);
750 	} else {
751 		kfree_skb(skb);
752 		__UDP6_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
753 				 proto == IPPROTO_UDPLITE);
754 	}
755 	return 0;
756 }
757 
758 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
759 		   int proto)
760 {
761 	const struct in6_addr *saddr, *daddr;
762 	struct net *net = dev_net(skb->dev);
763 	struct udphdr *uh;
764 	struct sock *sk;
765 	u32 ulen = 0;
766 
767 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
768 		goto discard;
769 
770 	saddr = &ipv6_hdr(skb)->saddr;
771 	daddr = &ipv6_hdr(skb)->daddr;
772 	uh = udp_hdr(skb);
773 
774 	ulen = ntohs(uh->len);
775 	if (ulen > skb->len)
776 		goto short_packet;
777 
778 	if (proto == IPPROTO_UDP) {
779 		/* UDP validates ulen. */
780 
781 		/* Check for jumbo payload */
782 		if (ulen == 0)
783 			ulen = skb->len;
784 
785 		if (ulen < sizeof(*uh))
786 			goto short_packet;
787 
788 		if (ulen < skb->len) {
789 			if (pskb_trim_rcsum(skb, ulen))
790 				goto short_packet;
791 			saddr = &ipv6_hdr(skb)->saddr;
792 			daddr = &ipv6_hdr(skb)->daddr;
793 			uh = udp_hdr(skb);
794 		}
795 	}
796 
797 	if (udp6_csum_init(skb, uh, proto))
798 		goto csum_error;
799 
800 	/*
801 	 *	Multicast receive code
802 	 */
803 	if (ipv6_addr_is_multicast(daddr))
804 		return __udp6_lib_mcast_deliver(net, skb,
805 				saddr, daddr, udptable, proto);
806 
807 	/* Unicast */
808 
809 	/*
810 	 * check socket cache ... must talk to Alan about his plans
811 	 * for sock caches... i'll skip this for now.
812 	 */
813 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
814 	if (sk) {
815 		int ret;
816 
817 		if (!uh->check && !udp_sk(sk)->no_check6_rx) {
818 			udp6_csum_zero_error(skb);
819 			goto csum_error;
820 		}
821 
822 		if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
823 			skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
824 						 ip6_compute_pseudo);
825 
826 		ret = udpv6_queue_rcv_skb(sk, skb);
827 
828 		/* a return value > 0 means to resubmit the input */
829 		if (ret > 0)
830 			return ret;
831 
832 		return 0;
833 	}
834 
835 	if (!uh->check) {
836 		udp6_csum_zero_error(skb);
837 		goto csum_error;
838 	}
839 
840 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
841 		goto discard;
842 
843 	if (udp_lib_checksum_complete(skb))
844 		goto csum_error;
845 
846 	__UDP6_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
847 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
848 
849 	kfree_skb(skb);
850 	return 0;
851 
852 short_packet:
853 	net_dbg_ratelimited("UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
854 			    proto == IPPROTO_UDPLITE ? "-Lite" : "",
855 			    saddr, ntohs(uh->source),
856 			    ulen, skb->len,
857 			    daddr, ntohs(uh->dest));
858 	goto discard;
859 csum_error:
860 	__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
861 discard:
862 	__UDP6_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
863 	kfree_skb(skb);
864 	return 0;
865 }
866 
867 static __inline__ int udpv6_rcv(struct sk_buff *skb)
868 {
869 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
870 }
871 
872 /*
873  * Throw away all pending data and cancel the corking. Socket is locked.
874  */
875 static void udp_v6_flush_pending_frames(struct sock *sk)
876 {
877 	struct udp_sock *up = udp_sk(sk);
878 
879 	if (up->pending == AF_INET)
880 		udp_flush_pending_frames(sk);
881 	else if (up->pending) {
882 		up->len = 0;
883 		up->pending = 0;
884 		ip6_flush_pending_frames(sk);
885 	}
886 }
887 
888 /**
889  *	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
890  *	@sk:	socket we are sending on
891  *	@skb:	sk_buff containing the filled-in UDP header
892  *		(checksum field must be zeroed out)
893  */
894 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
895 				 const struct in6_addr *saddr,
896 				 const struct in6_addr *daddr, int len)
897 {
898 	unsigned int offset;
899 	struct udphdr *uh = udp_hdr(skb);
900 	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
901 	__wsum csum = 0;
902 
903 	if (!frags) {
904 		/* Only one fragment on the socket.  */
905 		skb->csum_start = skb_transport_header(skb) - skb->head;
906 		skb->csum_offset = offsetof(struct udphdr, check);
907 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
908 	} else {
909 		/*
910 		 * HW-checksum won't work as there are two or more
911 		 * fragments on the socket so that all csums of sk_buffs
912 		 * should be together
913 		 */
914 		offset = skb_transport_offset(skb);
915 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
916 
917 		skb->ip_summed = CHECKSUM_NONE;
918 
919 		do {
920 			csum = csum_add(csum, frags->csum);
921 		} while ((frags = frags->next));
922 
923 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
924 					    csum);
925 		if (uh->check == 0)
926 			uh->check = CSUM_MANGLED_0;
927 	}
928 }
929 
930 /*
931  *	Sending
932  */
933 
934 static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
935 {
936 	struct sock *sk = skb->sk;
937 	struct udphdr *uh;
938 	int err = 0;
939 	int is_udplite = IS_UDPLITE(sk);
940 	__wsum csum = 0;
941 	int offset = skb_transport_offset(skb);
942 	int len = skb->len - offset;
943 
944 	/*
945 	 * Create a UDP header
946 	 */
947 	uh = udp_hdr(skb);
948 	uh->source = fl6->fl6_sport;
949 	uh->dest = fl6->fl6_dport;
950 	uh->len = htons(len);
951 	uh->check = 0;
952 
953 	if (is_udplite)
954 		csum = udplite_csum(skb);
955 	else if (udp_sk(sk)->no_check6_tx) {   /* UDP csum disabled */
956 		skb->ip_summed = CHECKSUM_NONE;
957 		goto send;
958 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
959 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
960 		goto send;
961 	} else
962 		csum = udp_csum(skb);
963 
964 	/* add protocol-dependent pseudo-header */
965 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
966 				    len, fl6->flowi6_proto, csum);
967 	if (uh->check == 0)
968 		uh->check = CSUM_MANGLED_0;
969 
970 send:
971 	err = ip6_send_skb(skb);
972 	if (err) {
973 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
974 			UDP6_INC_STATS(sock_net(sk),
975 				       UDP_MIB_SNDBUFERRORS, is_udplite);
976 			err = 0;
977 		}
978 	} else {
979 		UDP6_INC_STATS(sock_net(sk),
980 			       UDP_MIB_OUTDATAGRAMS, is_udplite);
981 	}
982 	return err;
983 }
984 
985 static int udp_v6_push_pending_frames(struct sock *sk)
986 {
987 	struct sk_buff *skb;
988 	struct udp_sock  *up = udp_sk(sk);
989 	struct flowi6 fl6;
990 	int err = 0;
991 
992 	if (up->pending == AF_INET)
993 		return udp_push_pending_frames(sk);
994 
995 	/* ip6_finish_skb will release the cork, so make a copy of
996 	 * fl6 here.
997 	 */
998 	fl6 = inet_sk(sk)->cork.fl.u.ip6;
999 
1000 	skb = ip6_finish_skb(sk);
1001 	if (!skb)
1002 		goto out;
1003 
1004 	err = udp_v6_send_skb(skb, &fl6);
1005 
1006 out:
1007 	up->len = 0;
1008 	up->pending = 0;
1009 	return err;
1010 }
1011 
1012 int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
1013 {
1014 	struct ipv6_txoptions opt_space;
1015 	struct udp_sock *up = udp_sk(sk);
1016 	struct inet_sock *inet = inet_sk(sk);
1017 	struct ipv6_pinfo *np = inet6_sk(sk);
1018 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
1019 	struct in6_addr *daddr, *final_p, final;
1020 	struct ipv6_txoptions *opt = NULL;
1021 	struct ipv6_txoptions *opt_to_free = NULL;
1022 	struct ip6_flowlabel *flowlabel = NULL;
1023 	struct flowi6 fl6;
1024 	struct dst_entry *dst;
1025 	struct ipcm6_cookie ipc6;
1026 	int addr_len = msg->msg_namelen;
1027 	int ulen = len;
1028 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
1029 	int err;
1030 	int connected = 0;
1031 	int is_udplite = IS_UDPLITE(sk);
1032 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1033 	struct sockcm_cookie sockc;
1034 
1035 	ipc6.hlimit = -1;
1036 	ipc6.tclass = -1;
1037 	ipc6.dontfrag = -1;
1038 
1039 	/* destination address check */
1040 	if (sin6) {
1041 		if (addr_len < offsetof(struct sockaddr, sa_data))
1042 			return -EINVAL;
1043 
1044 		switch (sin6->sin6_family) {
1045 		case AF_INET6:
1046 			if (addr_len < SIN6_LEN_RFC2133)
1047 				return -EINVAL;
1048 			daddr = &sin6->sin6_addr;
1049 			if (ipv6_addr_any(daddr) &&
1050 			    ipv6_addr_v4mapped(&np->saddr))
1051 				ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
1052 						       daddr);
1053 			break;
1054 		case AF_INET:
1055 			goto do_udp_sendmsg;
1056 		case AF_UNSPEC:
1057 			msg->msg_name = sin6 = NULL;
1058 			msg->msg_namelen = addr_len = 0;
1059 			daddr = NULL;
1060 			break;
1061 		default:
1062 			return -EINVAL;
1063 		}
1064 	} else if (!up->pending) {
1065 		if (sk->sk_state != TCP_ESTABLISHED)
1066 			return -EDESTADDRREQ;
1067 		daddr = &sk->sk_v6_daddr;
1068 	} else
1069 		daddr = NULL;
1070 
1071 	if (daddr) {
1072 		if (ipv6_addr_v4mapped(daddr)) {
1073 			struct sockaddr_in sin;
1074 			sin.sin_family = AF_INET;
1075 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1076 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
1077 			msg->msg_name = &sin;
1078 			msg->msg_namelen = sizeof(sin);
1079 do_udp_sendmsg:
1080 			if (__ipv6_only_sock(sk))
1081 				return -ENETUNREACH;
1082 			return udp_sendmsg(sk, msg, len);
1083 		}
1084 	}
1085 
1086 	if (up->pending == AF_INET)
1087 		return udp_sendmsg(sk, msg, len);
1088 
1089 	/* Rough check on arithmetic overflow,
1090 	   better check is made in ip6_append_data().
1091 	   */
1092 	if (len > INT_MAX - sizeof(struct udphdr))
1093 		return -EMSGSIZE;
1094 
1095 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1096 	if (up->pending) {
1097 		/*
1098 		 * There are pending frames.
1099 		 * The socket lock must be held while it's corked.
1100 		 */
1101 		lock_sock(sk);
1102 		if (likely(up->pending)) {
1103 			if (unlikely(up->pending != AF_INET6)) {
1104 				release_sock(sk);
1105 				return -EAFNOSUPPORT;
1106 			}
1107 			dst = NULL;
1108 			goto do_append_data;
1109 		}
1110 		release_sock(sk);
1111 	}
1112 	ulen += sizeof(struct udphdr);
1113 
1114 	memset(&fl6, 0, sizeof(fl6));
1115 
1116 	if (sin6) {
1117 		if (sin6->sin6_port == 0)
1118 			return -EINVAL;
1119 
1120 		fl6.fl6_dport = sin6->sin6_port;
1121 		daddr = &sin6->sin6_addr;
1122 
1123 		if (np->sndflow) {
1124 			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1125 			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1126 				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1127 				if (!flowlabel)
1128 					return -EINVAL;
1129 			}
1130 		}
1131 
1132 		/*
1133 		 * Otherwise it will be difficult to maintain
1134 		 * sk->sk_dst_cache.
1135 		 */
1136 		if (sk->sk_state == TCP_ESTABLISHED &&
1137 		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
1138 			daddr = &sk->sk_v6_daddr;
1139 
1140 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1141 		    sin6->sin6_scope_id &&
1142 		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
1143 			fl6.flowi6_oif = sin6->sin6_scope_id;
1144 	} else {
1145 		if (sk->sk_state != TCP_ESTABLISHED)
1146 			return -EDESTADDRREQ;
1147 
1148 		fl6.fl6_dport = inet->inet_dport;
1149 		daddr = &sk->sk_v6_daddr;
1150 		fl6.flowlabel = np->flow_label;
1151 		connected = 1;
1152 	}
1153 
1154 	if (!fl6.flowi6_oif)
1155 		fl6.flowi6_oif = sk->sk_bound_dev_if;
1156 
1157 	if (!fl6.flowi6_oif)
1158 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1159 
1160 	fl6.flowi6_mark = sk->sk_mark;
1161 	fl6.flowi6_uid = sk->sk_uid;
1162 	sockc.tsflags = sk->sk_tsflags;
1163 
1164 	if (msg->msg_controllen) {
1165 		opt = &opt_space;
1166 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1167 		opt->tot_len = sizeof(*opt);
1168 		ipc6.opt = opt;
1169 
1170 		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6, &sockc);
1171 		if (err < 0) {
1172 			fl6_sock_release(flowlabel);
1173 			return err;
1174 		}
1175 		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1176 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1177 			if (!flowlabel)
1178 				return -EINVAL;
1179 		}
1180 		if (!(opt->opt_nflen|opt->opt_flen))
1181 			opt = NULL;
1182 		connected = 0;
1183 	}
1184 	if (!opt) {
1185 		opt = txopt_get(np);
1186 		opt_to_free = opt;
1187 	}
1188 	if (flowlabel)
1189 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1190 	opt = ipv6_fixup_options(&opt_space, opt);
1191 	ipc6.opt = opt;
1192 
1193 	fl6.flowi6_proto = sk->sk_protocol;
1194 	if (!ipv6_addr_any(daddr))
1195 		fl6.daddr = *daddr;
1196 	else
1197 		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1198 	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1199 		fl6.saddr = np->saddr;
1200 	fl6.fl6_sport = inet->inet_sport;
1201 
1202 	final_p = fl6_update_dst(&fl6, opt, &final);
1203 	if (final_p)
1204 		connected = 0;
1205 
1206 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1207 		fl6.flowi6_oif = np->mcast_oif;
1208 		connected = 0;
1209 	} else if (!fl6.flowi6_oif)
1210 		fl6.flowi6_oif = np->ucast_oif;
1211 
1212 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1213 
1214 	if (ipc6.tclass < 0)
1215 		ipc6.tclass = np->tclass;
1216 
1217 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
1218 
1219 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p);
1220 	if (IS_ERR(dst)) {
1221 		err = PTR_ERR(dst);
1222 		dst = NULL;
1223 		goto out;
1224 	}
1225 
1226 	if (ipc6.hlimit < 0)
1227 		ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
1228 
1229 	if (msg->msg_flags&MSG_CONFIRM)
1230 		goto do_confirm;
1231 back_from_confirm:
1232 
1233 	/* Lockless fast path for the non-corking case */
1234 	if (!corkreq) {
1235 		struct sk_buff *skb;
1236 
1237 		skb = ip6_make_skb(sk, getfrag, msg, ulen,
1238 				   sizeof(struct udphdr), &ipc6,
1239 				   &fl6, (struct rt6_info *)dst,
1240 				   msg->msg_flags, &sockc);
1241 		err = PTR_ERR(skb);
1242 		if (!IS_ERR_OR_NULL(skb))
1243 			err = udp_v6_send_skb(skb, &fl6);
1244 		goto release_dst;
1245 	}
1246 
1247 	lock_sock(sk);
1248 	if (unlikely(up->pending)) {
1249 		/* The socket is already corked while preparing it. */
1250 		/* ... which is an evident application bug. --ANK */
1251 		release_sock(sk);
1252 
1253 		net_dbg_ratelimited("udp cork app bug 2\n");
1254 		err = -EINVAL;
1255 		goto out;
1256 	}
1257 
1258 	up->pending = AF_INET6;
1259 
1260 do_append_data:
1261 	if (ipc6.dontfrag < 0)
1262 		ipc6.dontfrag = np->dontfrag;
1263 	up->len += ulen;
1264 	err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr),
1265 			      &ipc6, &fl6, (struct rt6_info *)dst,
1266 			      corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, &sockc);
1267 	if (err)
1268 		udp_v6_flush_pending_frames(sk);
1269 	else if (!corkreq)
1270 		err = udp_v6_push_pending_frames(sk);
1271 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1272 		up->pending = 0;
1273 
1274 	if (err > 0)
1275 		err = np->recverr ? net_xmit_errno(err) : 0;
1276 	release_sock(sk);
1277 
1278 release_dst:
1279 	if (dst) {
1280 		if (connected) {
1281 			ip6_dst_store(sk, dst,
1282 				      ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
1283 				      &sk->sk_v6_daddr : NULL,
1284 #ifdef CONFIG_IPV6_SUBTREES
1285 				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1286 				      &np->saddr :
1287 #endif
1288 				      NULL);
1289 		} else {
1290 			dst_release(dst);
1291 		}
1292 		dst = NULL;
1293 	}
1294 
1295 out:
1296 	dst_release(dst);
1297 	fl6_sock_release(flowlabel);
1298 	txopt_put(opt_to_free);
1299 	if (!err)
1300 		return len;
1301 	/*
1302 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1303 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1304 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1305 	 * things).  We could add another new stat but at least for now that
1306 	 * seems like overkill.
1307 	 */
1308 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1309 		UDP6_INC_STATS(sock_net(sk),
1310 			       UDP_MIB_SNDBUFERRORS, is_udplite);
1311 	}
1312 	return err;
1313 
1314 do_confirm:
1315 	if (msg->msg_flags & MSG_PROBE)
1316 		dst_confirm_neigh(dst, &fl6.daddr);
1317 	if (!(msg->msg_flags&MSG_PROBE) || len)
1318 		goto back_from_confirm;
1319 	err = 0;
1320 	goto out;
1321 }
1322 
1323 void udpv6_destroy_sock(struct sock *sk)
1324 {
1325 	struct udp_sock *up = udp_sk(sk);
1326 	lock_sock(sk);
1327 	udp_v6_flush_pending_frames(sk);
1328 	release_sock(sk);
1329 
1330 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
1331 		void (*encap_destroy)(struct sock *sk);
1332 		encap_destroy = ACCESS_ONCE(up->encap_destroy);
1333 		if (encap_destroy)
1334 			encap_destroy(sk);
1335 	}
1336 
1337 	inet6_destroy_sock(sk);
1338 }
1339 
1340 /*
1341  *	Socket option code for UDP
1342  */
1343 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1344 		     char __user *optval, unsigned int optlen)
1345 {
1346 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1347 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1348 					  udp_v6_push_pending_frames);
1349 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1350 }
1351 
1352 #ifdef CONFIG_COMPAT
1353 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1354 			    char __user *optval, unsigned int optlen)
1355 {
1356 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1357 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1358 					  udp_v6_push_pending_frames);
1359 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1360 }
1361 #endif
1362 
1363 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1364 		     char __user *optval, int __user *optlen)
1365 {
1366 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1367 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1368 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1369 }
1370 
1371 #ifdef CONFIG_COMPAT
1372 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1373 			    char __user *optval, int __user *optlen)
1374 {
1375 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1376 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1377 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1378 }
1379 #endif
1380 
1381 static const struct inet6_protocol udpv6_protocol = {
1382 	.handler	=	udpv6_rcv,
1383 	.err_handler	=	udpv6_err,
1384 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1385 };
1386 
1387 /* ------------------------------------------------------------------------ */
1388 #ifdef CONFIG_PROC_FS
1389 int udp6_seq_show(struct seq_file *seq, void *v)
1390 {
1391 	if (v == SEQ_START_TOKEN) {
1392 		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1393 	} else {
1394 		int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1395 		struct inet_sock *inet = inet_sk(v);
1396 		__u16 srcp = ntohs(inet->inet_sport);
1397 		__u16 destp = ntohs(inet->inet_dport);
1398 		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
1399 	}
1400 	return 0;
1401 }
1402 
1403 static const struct file_operations udp6_afinfo_seq_fops = {
1404 	.owner    = THIS_MODULE,
1405 	.open     = udp_seq_open,
1406 	.read     = seq_read,
1407 	.llseek   = seq_lseek,
1408 	.release  = seq_release_net
1409 };
1410 
1411 static struct udp_seq_afinfo udp6_seq_afinfo = {
1412 	.name		= "udp6",
1413 	.family		= AF_INET6,
1414 	.udp_table	= &udp_table,
1415 	.seq_fops	= &udp6_afinfo_seq_fops,
1416 	.seq_ops	= {
1417 		.show		= udp6_seq_show,
1418 	},
1419 };
1420 
1421 int __net_init udp6_proc_init(struct net *net)
1422 {
1423 	return udp_proc_register(net, &udp6_seq_afinfo);
1424 }
1425 
1426 void udp6_proc_exit(struct net *net)
1427 {
1428 	udp_proc_unregister(net, &udp6_seq_afinfo);
1429 }
1430 #endif /* CONFIG_PROC_FS */
1431 
1432 /* ------------------------------------------------------------------------ */
1433 
1434 struct proto udpv6_prot = {
1435 	.name		   = "UDPv6",
1436 	.owner		   = THIS_MODULE,
1437 	.close		   = udp_lib_close,
1438 	.connect	   = ip6_datagram_connect,
1439 	.disconnect	   = udp_disconnect,
1440 	.ioctl		   = udp_ioctl,
1441 	.init		   = udp_init_sock,
1442 	.destroy	   = udpv6_destroy_sock,
1443 	.setsockopt	   = udpv6_setsockopt,
1444 	.getsockopt	   = udpv6_getsockopt,
1445 	.sendmsg	   = udpv6_sendmsg,
1446 	.recvmsg	   = udpv6_recvmsg,
1447 	.release_cb	   = ip6_datagram_release_cb,
1448 	.hash		   = udp_lib_hash,
1449 	.unhash		   = udp_lib_unhash,
1450 	.rehash		   = udp_v6_rehash,
1451 	.get_port	   = udp_v6_get_port,
1452 	.memory_allocated  = &udp_memory_allocated,
1453 	.sysctl_mem	   = sysctl_udp_mem,
1454 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1455 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1456 	.obj_size	   = sizeof(struct udp6_sock),
1457 	.h.udp_table	   = &udp_table,
1458 #ifdef CONFIG_COMPAT
1459 	.compat_setsockopt = compat_udpv6_setsockopt,
1460 	.compat_getsockopt = compat_udpv6_getsockopt,
1461 #endif
1462 	.diag_destroy      = udp_abort,
1463 };
1464 
1465 static struct inet_protosw udpv6_protosw = {
1466 	.type =      SOCK_DGRAM,
1467 	.protocol =  IPPROTO_UDP,
1468 	.prot =      &udpv6_prot,
1469 	.ops =       &inet6_dgram_ops,
1470 	.flags =     INET_PROTOSW_PERMANENT,
1471 };
1472 
1473 int __init udpv6_init(void)
1474 {
1475 	int ret;
1476 
1477 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1478 	if (ret)
1479 		goto out;
1480 
1481 	ret = inet6_register_protosw(&udpv6_protosw);
1482 	if (ret)
1483 		goto out_udpv6_protocol;
1484 out:
1485 	return ret;
1486 
1487 out_udpv6_protocol:
1488 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1489 	goto out;
1490 }
1491 
1492 void udpv6_exit(void)
1493 {
1494 	inet6_unregister_protosw(&udpv6_protosw);
1495 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1496 }
1497