xref: /openbmc/linux/net/ipv6/udp.c (revision e23feb16)
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 <asm/uaccess.h>
39 
40 #include <net/ndisc.h>
41 #include <net/protocol.h>
42 #include <net/transp_v6.h>
43 #include <net/ip6_route.h>
44 #include <net/raw.h>
45 #include <net/tcp_states.h>
46 #include <net/ip6_checksum.h>
47 #include <net/xfrm.h>
48 #include <net/inet6_hashtables.h>
49 #include <net/busy_poll.h>
50 
51 #include <linux/proc_fs.h>
52 #include <linux/seq_file.h>
53 #include <trace/events/skb.h>
54 #include "udp_impl.h"
55 
56 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
57 {
58 	const struct in6_addr *sk_rcv_saddr6 = &inet6_sk(sk)->rcv_saddr;
59 	const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
60 	__be32 sk1_rcv_saddr = sk_rcv_saddr(sk);
61 	__be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
62 	int sk_ipv6only = ipv6_only_sock(sk);
63 	int sk2_ipv6only = inet_v6_ipv6only(sk2);
64 	int addr_type = ipv6_addr_type(sk_rcv_saddr6);
65 	int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
66 
67 	/* if both are mapped, treat as IPv4 */
68 	if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED)
69 		return (!sk2_ipv6only &&
70 			(!sk1_rcv_saddr || !sk2_rcv_saddr ||
71 			  sk1_rcv_saddr == sk2_rcv_saddr));
72 
73 	if (addr_type2 == IPV6_ADDR_ANY &&
74 	    !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
75 		return 1;
76 
77 	if (addr_type == IPV6_ADDR_ANY &&
78 	    !(sk_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
79 		return 1;
80 
81 	if (sk2_rcv_saddr6 &&
82 	    ipv6_addr_equal(sk_rcv_saddr6, sk2_rcv_saddr6))
83 		return 1;
84 
85 	return 0;
86 }
87 
88 static unsigned int udp6_portaddr_hash(struct net *net,
89 				       const struct in6_addr *addr6,
90 				       unsigned int port)
91 {
92 	unsigned int hash, mix = net_hash_mix(net);
93 
94 	if (ipv6_addr_any(addr6))
95 		hash = jhash_1word(0, mix);
96 	else if (ipv6_addr_v4mapped(addr6))
97 		hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
98 	else
99 		hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);
100 
101 	return hash ^ port;
102 }
103 
104 
105 int udp_v6_get_port(struct sock *sk, unsigned short snum)
106 {
107 	unsigned int hash2_nulladdr =
108 		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
109 	unsigned int hash2_partial =
110 		udp6_portaddr_hash(sock_net(sk), &inet6_sk(sk)->rcv_saddr, 0);
111 
112 	/* precompute partial secondary hash */
113 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
114 	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
115 }
116 
117 static void udp_v6_rehash(struct sock *sk)
118 {
119 	u16 new_hash = udp6_portaddr_hash(sock_net(sk),
120 					  &inet6_sk(sk)->rcv_saddr,
121 					  inet_sk(sk)->inet_num);
122 
123 	udp_lib_rehash(sk, new_hash);
124 }
125 
126 static inline int compute_score(struct sock *sk, struct net *net,
127 				unsigned short hnum,
128 				const struct in6_addr *saddr, __be16 sport,
129 				const struct in6_addr *daddr, __be16 dport,
130 				int dif)
131 {
132 	int score = -1;
133 
134 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
135 			sk->sk_family == PF_INET6) {
136 		struct ipv6_pinfo *np = inet6_sk(sk);
137 		struct inet_sock *inet = inet_sk(sk);
138 
139 		score = 0;
140 		if (inet->inet_dport) {
141 			if (inet->inet_dport != sport)
142 				return -1;
143 			score++;
144 		}
145 		if (!ipv6_addr_any(&np->rcv_saddr)) {
146 			if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
147 				return -1;
148 			score++;
149 		}
150 		if (!ipv6_addr_any(&np->daddr)) {
151 			if (!ipv6_addr_equal(&np->daddr, saddr))
152 				return -1;
153 			score++;
154 		}
155 		if (sk->sk_bound_dev_if) {
156 			if (sk->sk_bound_dev_if != dif)
157 				return -1;
158 			score++;
159 		}
160 	}
161 	return score;
162 }
163 
164 #define SCORE2_MAX (1 + 1 + 1)
165 static inline int compute_score2(struct sock *sk, struct net *net,
166 				const struct in6_addr *saddr, __be16 sport,
167 				const struct in6_addr *daddr, unsigned short hnum,
168 				int dif)
169 {
170 	int score = -1;
171 
172 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
173 			sk->sk_family == PF_INET6) {
174 		struct ipv6_pinfo *np = inet6_sk(sk);
175 		struct inet_sock *inet = inet_sk(sk);
176 
177 		if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
178 			return -1;
179 		score = 0;
180 		if (inet->inet_dport) {
181 			if (inet->inet_dport != sport)
182 				return -1;
183 			score++;
184 		}
185 		if (!ipv6_addr_any(&np->daddr)) {
186 			if (!ipv6_addr_equal(&np->daddr, saddr))
187 				return -1;
188 			score++;
189 		}
190 		if (sk->sk_bound_dev_if) {
191 			if (sk->sk_bound_dev_if != dif)
192 				return -1;
193 			score++;
194 		}
195 	}
196 	return score;
197 }
198 
199 
200 /* called with read_rcu_lock() */
201 static struct sock *udp6_lib_lookup2(struct net *net,
202 		const struct in6_addr *saddr, __be16 sport,
203 		const struct in6_addr *daddr, unsigned int hnum, int dif,
204 		struct udp_hslot *hslot2, unsigned int slot2)
205 {
206 	struct sock *sk, *result;
207 	struct hlist_nulls_node *node;
208 	int score, badness, matches = 0, reuseport = 0;
209 	u32 hash = 0;
210 
211 begin:
212 	result = NULL;
213 	badness = -1;
214 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
215 		score = compute_score2(sk, net, saddr, sport,
216 				      daddr, hnum, dif);
217 		if (score > badness) {
218 			result = sk;
219 			badness = score;
220 			reuseport = sk->sk_reuseport;
221 			if (reuseport) {
222 				hash = inet6_ehashfn(net, daddr, hnum,
223 						     saddr, sport);
224 				matches = 1;
225 			} else if (score == SCORE2_MAX)
226 				goto exact_match;
227 		} else if (score == badness && reuseport) {
228 			matches++;
229 			if (((u64)hash * matches) >> 32 == 0)
230 				result = sk;
231 			hash = next_pseudo_random32(hash);
232 		}
233 	}
234 	/*
235 	 * if the nulls value we got at the end of this lookup is
236 	 * not the expected one, we must restart lookup.
237 	 * We probably met an item that was moved to another chain.
238 	 */
239 	if (get_nulls_value(node) != slot2)
240 		goto begin;
241 
242 	if (result) {
243 exact_match:
244 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
245 			result = NULL;
246 		else if (unlikely(compute_score2(result, net, saddr, sport,
247 				  daddr, hnum, dif) < badness)) {
248 			sock_put(result);
249 			goto begin;
250 		}
251 	}
252 	return result;
253 }
254 
255 struct sock *__udp6_lib_lookup(struct net *net,
256 				      const struct in6_addr *saddr, __be16 sport,
257 				      const struct in6_addr *daddr, __be16 dport,
258 				      int dif, struct udp_table *udptable)
259 {
260 	struct sock *sk, *result;
261 	struct hlist_nulls_node *node;
262 	unsigned short hnum = ntohs(dport);
263 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
264 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
265 	int score, badness, matches = 0, reuseport = 0;
266 	u32 hash = 0;
267 
268 	rcu_read_lock();
269 	if (hslot->count > 10) {
270 		hash2 = udp6_portaddr_hash(net, daddr, hnum);
271 		slot2 = hash2 & udptable->mask;
272 		hslot2 = &udptable->hash2[slot2];
273 		if (hslot->count < hslot2->count)
274 			goto begin;
275 
276 		result = udp6_lib_lookup2(net, saddr, sport,
277 					  daddr, hnum, dif,
278 					  hslot2, slot2);
279 		if (!result) {
280 			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
281 			slot2 = hash2 & udptable->mask;
282 			hslot2 = &udptable->hash2[slot2];
283 			if (hslot->count < hslot2->count)
284 				goto begin;
285 
286 			result = udp6_lib_lookup2(net, saddr, sport,
287 						  &in6addr_any, hnum, dif,
288 						  hslot2, slot2);
289 		}
290 		rcu_read_unlock();
291 		return result;
292 	}
293 begin:
294 	result = NULL;
295 	badness = -1;
296 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
297 		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
298 		if (score > badness) {
299 			result = sk;
300 			badness = score;
301 			reuseport = sk->sk_reuseport;
302 			if (reuseport) {
303 				hash = inet6_ehashfn(net, daddr, hnum,
304 						     saddr, sport);
305 				matches = 1;
306 			}
307 		} else if (score == badness && reuseport) {
308 			matches++;
309 			if (((u64)hash * matches) >> 32 == 0)
310 				result = sk;
311 			hash = next_pseudo_random32(hash);
312 		}
313 	}
314 	/*
315 	 * if the nulls value we got at the end of this lookup is
316 	 * not the expected one, we must restart lookup.
317 	 * We probably met an item that was moved to another chain.
318 	 */
319 	if (get_nulls_value(node) != slot)
320 		goto begin;
321 
322 	if (result) {
323 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
324 			result = NULL;
325 		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
326 					daddr, dport, dif) < badness)) {
327 			sock_put(result);
328 			goto begin;
329 		}
330 	}
331 	rcu_read_unlock();
332 	return result;
333 }
334 EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
335 
336 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
337 					  __be16 sport, __be16 dport,
338 					  struct udp_table *udptable)
339 {
340 	struct sock *sk;
341 	const struct ipv6hdr *iph = ipv6_hdr(skb);
342 
343 	if (unlikely(sk = skb_steal_sock(skb)))
344 		return sk;
345 	return __udp6_lib_lookup(dev_net(skb_dst(skb)->dev), &iph->saddr, sport,
346 				 &iph->daddr, dport, inet6_iif(skb),
347 				 udptable);
348 }
349 
350 struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
351 			     const struct in6_addr *daddr, __be16 dport, int dif)
352 {
353 	return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
354 }
355 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
356 
357 
358 /*
359  * 	This should be easy, if there is something there we
360  * 	return it, otherwise we block.
361  */
362 
363 int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
364 		  struct msghdr *msg, size_t len,
365 		  int noblock, int flags, int *addr_len)
366 {
367 	struct ipv6_pinfo *np = inet6_sk(sk);
368 	struct inet_sock *inet = inet_sk(sk);
369 	struct sk_buff *skb;
370 	unsigned int ulen, copied;
371 	int peeked, off = 0;
372 	int err;
373 	int is_udplite = IS_UDPLITE(sk);
374 	int is_udp4;
375 	bool slow;
376 
377 	if (addr_len)
378 		*addr_len = sizeof(struct sockaddr_in6);
379 
380 	if (flags & MSG_ERRQUEUE)
381 		return ipv6_recv_error(sk, msg, len);
382 
383 	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
384 		return ipv6_recv_rxpmtu(sk, msg, len);
385 
386 try_again:
387 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
388 				  &peeked, &off, &err);
389 	if (!skb)
390 		goto out;
391 
392 	ulen = skb->len - sizeof(struct udphdr);
393 	copied = len;
394 	if (copied > ulen)
395 		copied = ulen;
396 	else if (copied < ulen)
397 		msg->msg_flags |= MSG_TRUNC;
398 
399 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
400 
401 	/*
402 	 * If checksum is needed at all, try to do it while copying the
403 	 * data.  If the data is truncated, or if we only want a partial
404 	 * coverage checksum (UDP-Lite), do it before the copy.
405 	 */
406 
407 	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
408 		if (udp_lib_checksum_complete(skb))
409 			goto csum_copy_err;
410 	}
411 
412 	if (skb_csum_unnecessary(skb))
413 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
414 					      msg->msg_iov, copied);
415 	else {
416 		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
417 		if (err == -EINVAL)
418 			goto csum_copy_err;
419 	}
420 	if (unlikely(err)) {
421 		trace_kfree_skb(skb, udpv6_recvmsg);
422 		if (!peeked) {
423 			atomic_inc(&sk->sk_drops);
424 			if (is_udp4)
425 				UDP_INC_STATS_USER(sock_net(sk),
426 						   UDP_MIB_INERRORS,
427 						   is_udplite);
428 			else
429 				UDP6_INC_STATS_USER(sock_net(sk),
430 						    UDP_MIB_INERRORS,
431 						    is_udplite);
432 		}
433 		goto out_free;
434 	}
435 	if (!peeked) {
436 		if (is_udp4)
437 			UDP_INC_STATS_USER(sock_net(sk),
438 					UDP_MIB_INDATAGRAMS, is_udplite);
439 		else
440 			UDP6_INC_STATS_USER(sock_net(sk),
441 					UDP_MIB_INDATAGRAMS, is_udplite);
442 	}
443 
444 	sock_recv_ts_and_drops(msg, sk, skb);
445 
446 	/* Copy the address. */
447 	if (msg->msg_name) {
448 		struct sockaddr_in6 *sin6;
449 
450 		sin6 = (struct sockaddr_in6 *) msg->msg_name;
451 		sin6->sin6_family = AF_INET6;
452 		sin6->sin6_port = udp_hdr(skb)->source;
453 		sin6->sin6_flowinfo = 0;
454 
455 		if (is_udp4) {
456 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
457 					       &sin6->sin6_addr);
458 			sin6->sin6_scope_id = 0;
459 		} else {
460 			sin6->sin6_addr = ipv6_hdr(skb)->saddr;
461 			sin6->sin6_scope_id =
462 				ipv6_iface_scope_id(&sin6->sin6_addr,
463 						    IP6CB(skb)->iif);
464 		}
465 
466 	}
467 	if (is_udp4) {
468 		if (inet->cmsg_flags)
469 			ip_cmsg_recv(msg, skb);
470 	} else {
471 		if (np->rxopt.all)
472 			ip6_datagram_recv_ctl(sk, msg, skb);
473 	}
474 
475 	err = copied;
476 	if (flags & MSG_TRUNC)
477 		err = ulen;
478 
479 out_free:
480 	skb_free_datagram_locked(sk, skb);
481 out:
482 	return err;
483 
484 csum_copy_err:
485 	slow = lock_sock_fast(sk);
486 	if (!skb_kill_datagram(sk, skb, flags)) {
487 		if (is_udp4) {
488 			UDP_INC_STATS_USER(sock_net(sk),
489 					UDP_MIB_CSUMERRORS, is_udplite);
490 			UDP_INC_STATS_USER(sock_net(sk),
491 					UDP_MIB_INERRORS, is_udplite);
492 		} else {
493 			UDP6_INC_STATS_USER(sock_net(sk),
494 					UDP_MIB_CSUMERRORS, is_udplite);
495 			UDP6_INC_STATS_USER(sock_net(sk),
496 					UDP_MIB_INERRORS, is_udplite);
497 		}
498 	}
499 	unlock_sock_fast(sk, slow);
500 
501 	if (noblock)
502 		return -EAGAIN;
503 
504 	/* starting over for a new packet */
505 	msg->msg_flags &= ~MSG_TRUNC;
506 	goto try_again;
507 }
508 
509 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
510 		    u8 type, u8 code, int offset, __be32 info,
511 		    struct udp_table *udptable)
512 {
513 	struct ipv6_pinfo *np;
514 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
515 	const struct in6_addr *saddr = &hdr->saddr;
516 	const struct in6_addr *daddr = &hdr->daddr;
517 	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
518 	struct sock *sk;
519 	int err;
520 
521 	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
522 			       saddr, uh->source, inet6_iif(skb), udptable);
523 	if (sk == NULL)
524 		return;
525 
526 	if (type == ICMPV6_PKT_TOOBIG)
527 		ip6_sk_update_pmtu(skb, sk, info);
528 	if (type == NDISC_REDIRECT) {
529 		ip6_sk_redirect(skb, sk);
530 		goto out;
531 	}
532 
533 	np = inet6_sk(sk);
534 
535 	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
536 		goto out;
537 
538 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
539 		goto out;
540 
541 	if (np->recverr)
542 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
543 
544 	sk->sk_err = err;
545 	sk->sk_error_report(sk);
546 out:
547 	sock_put(sk);
548 }
549 
550 static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
551 {
552 	int rc;
553 
554 	if (!ipv6_addr_any(&inet6_sk(sk)->daddr))
555 		sock_rps_save_rxhash(sk, skb);
556 
557 	rc = sock_queue_rcv_skb(sk, skb);
558 	if (rc < 0) {
559 		int is_udplite = IS_UDPLITE(sk);
560 
561 		/* Note that an ENOMEM error is charged twice */
562 		if (rc == -ENOMEM)
563 			UDP6_INC_STATS_BH(sock_net(sk),
564 					UDP_MIB_RCVBUFERRORS, is_udplite);
565 		UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
566 		kfree_skb(skb);
567 		return -1;
568 	}
569 	return 0;
570 }
571 
572 static __inline__ void udpv6_err(struct sk_buff *skb,
573 				 struct inet6_skb_parm *opt, u8 type,
574 				 u8 code, int offset, __be32 info     )
575 {
576 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
577 }
578 
579 static struct static_key udpv6_encap_needed __read_mostly;
580 void udpv6_encap_enable(void)
581 {
582 	if (!static_key_enabled(&udpv6_encap_needed))
583 		static_key_slow_inc(&udpv6_encap_needed);
584 }
585 EXPORT_SYMBOL(udpv6_encap_enable);
586 
587 int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
588 {
589 	struct udp_sock *up = udp_sk(sk);
590 	int rc;
591 	int is_udplite = IS_UDPLITE(sk);
592 
593 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
594 		goto drop;
595 
596 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
597 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
598 
599 		/*
600 		 * This is an encapsulation socket so pass the skb to
601 		 * the socket's udp_encap_rcv() hook. Otherwise, just
602 		 * fall through and pass this up the UDP socket.
603 		 * up->encap_rcv() returns the following value:
604 		 * =0 if skb was successfully passed to the encap
605 		 *    handler or was discarded by it.
606 		 * >0 if skb should be passed on to UDP.
607 		 * <0 if skb should be resubmitted as proto -N
608 		 */
609 
610 		/* if we're overly short, let UDP handle it */
611 		encap_rcv = ACCESS_ONCE(up->encap_rcv);
612 		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
613 			int ret;
614 
615 			ret = encap_rcv(sk, skb);
616 			if (ret <= 0) {
617 				UDP_INC_STATS_BH(sock_net(sk),
618 						 UDP_MIB_INDATAGRAMS,
619 						 is_udplite);
620 				return -ret;
621 			}
622 		}
623 
624 		/* FALLTHROUGH -- it's a UDP Packet */
625 	}
626 
627 	/*
628 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
629 	 */
630 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
631 
632 		if (up->pcrlen == 0) {          /* full coverage was set  */
633 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
634 				" %d while full coverage %d requested\n",
635 				UDP_SKB_CB(skb)->cscov, skb->len);
636 			goto drop;
637 		}
638 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
639 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
640 						    "too small, need min %d\n",
641 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
642 			goto drop;
643 		}
644 	}
645 
646 	if (rcu_access_pointer(sk->sk_filter)) {
647 		if (udp_lib_checksum_complete(skb))
648 			goto csum_error;
649 	}
650 
651 	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
652 		goto drop;
653 
654 	skb_dst_drop(skb);
655 
656 	bh_lock_sock(sk);
657 	rc = 0;
658 	if (!sock_owned_by_user(sk))
659 		rc = __udpv6_queue_rcv_skb(sk, skb);
660 	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
661 		bh_unlock_sock(sk);
662 		goto drop;
663 	}
664 	bh_unlock_sock(sk);
665 
666 	return rc;
667 csum_error:
668 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
669 drop:
670 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
671 	atomic_inc(&sk->sk_drops);
672 	kfree_skb(skb);
673 	return -1;
674 }
675 
676 static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
677 				      __be16 loc_port, const struct in6_addr *loc_addr,
678 				      __be16 rmt_port, const struct in6_addr *rmt_addr,
679 				      int dif)
680 {
681 	struct hlist_nulls_node *node;
682 	struct sock *s = sk;
683 	unsigned short num = ntohs(loc_port);
684 
685 	sk_nulls_for_each_from(s, node) {
686 		struct inet_sock *inet = inet_sk(s);
687 
688 		if (!net_eq(sock_net(s), net))
689 			continue;
690 
691 		if (udp_sk(s)->udp_port_hash == num &&
692 		    s->sk_family == PF_INET6) {
693 			struct ipv6_pinfo *np = inet6_sk(s);
694 			if (inet->inet_dport) {
695 				if (inet->inet_dport != rmt_port)
696 					continue;
697 			}
698 			if (!ipv6_addr_any(&np->daddr) &&
699 			    !ipv6_addr_equal(&np->daddr, rmt_addr))
700 				continue;
701 
702 			if (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)
703 				continue;
704 
705 			if (!ipv6_addr_any(&np->rcv_saddr)) {
706 				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
707 					continue;
708 			}
709 			if (!inet6_mc_check(s, loc_addr, rmt_addr))
710 				continue;
711 			return s;
712 		}
713 	}
714 	return NULL;
715 }
716 
717 static void flush_stack(struct sock **stack, unsigned int count,
718 			struct sk_buff *skb, unsigned int final)
719 {
720 	struct sk_buff *skb1 = NULL;
721 	struct sock *sk;
722 	unsigned int i;
723 
724 	for (i = 0; i < count; i++) {
725 		sk = stack[i];
726 		if (likely(skb1 == NULL))
727 			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
728 		if (!skb1) {
729 			atomic_inc(&sk->sk_drops);
730 			UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
731 					  IS_UDPLITE(sk));
732 			UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
733 					  IS_UDPLITE(sk));
734 		}
735 
736 		if (skb1 && udpv6_queue_rcv_skb(sk, skb1) <= 0)
737 			skb1 = NULL;
738 	}
739 	if (unlikely(skb1))
740 		kfree_skb(skb1);
741 }
742 /*
743  * Note: called only from the BH handler context,
744  * so we don't need to lock the hashes.
745  */
746 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
747 		const struct in6_addr *saddr, const struct in6_addr *daddr,
748 		struct udp_table *udptable)
749 {
750 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
751 	const struct udphdr *uh = udp_hdr(skb);
752 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
753 	int dif;
754 	unsigned int i, count = 0;
755 
756 	spin_lock(&hslot->lock);
757 	sk = sk_nulls_head(&hslot->head);
758 	dif = inet6_iif(skb);
759 	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
760 	while (sk) {
761 		stack[count++] = sk;
762 		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
763 				       uh->source, saddr, dif);
764 		if (unlikely(count == ARRAY_SIZE(stack))) {
765 			if (!sk)
766 				break;
767 			flush_stack(stack, count, skb, ~0);
768 			count = 0;
769 		}
770 	}
771 	/*
772 	 * before releasing the lock, we must take reference on sockets
773 	 */
774 	for (i = 0; i < count; i++)
775 		sock_hold(stack[i]);
776 
777 	spin_unlock(&hslot->lock);
778 
779 	if (count) {
780 		flush_stack(stack, count, skb, count - 1);
781 
782 		for (i = 0; i < count; i++)
783 			sock_put(stack[i]);
784 	} else {
785 		kfree_skb(skb);
786 	}
787 	return 0;
788 }
789 
790 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
791 		   int proto)
792 {
793 	struct net *net = dev_net(skb->dev);
794 	struct sock *sk;
795 	struct udphdr *uh;
796 	const struct in6_addr *saddr, *daddr;
797 	u32 ulen = 0;
798 
799 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
800 		goto discard;
801 
802 	saddr = &ipv6_hdr(skb)->saddr;
803 	daddr = &ipv6_hdr(skb)->daddr;
804 	uh = udp_hdr(skb);
805 
806 	ulen = ntohs(uh->len);
807 	if (ulen > skb->len)
808 		goto short_packet;
809 
810 	if (proto == IPPROTO_UDP) {
811 		/* UDP validates ulen. */
812 
813 		/* Check for jumbo payload */
814 		if (ulen == 0)
815 			ulen = skb->len;
816 
817 		if (ulen < sizeof(*uh))
818 			goto short_packet;
819 
820 		if (ulen < skb->len) {
821 			if (pskb_trim_rcsum(skb, ulen))
822 				goto short_packet;
823 			saddr = &ipv6_hdr(skb)->saddr;
824 			daddr = &ipv6_hdr(skb)->daddr;
825 			uh = udp_hdr(skb);
826 		}
827 	}
828 
829 	if (udp6_csum_init(skb, uh, proto))
830 		goto csum_error;
831 
832 	/*
833 	 *	Multicast receive code
834 	 */
835 	if (ipv6_addr_is_multicast(daddr))
836 		return __udp6_lib_mcast_deliver(net, skb,
837 				saddr, daddr, udptable);
838 
839 	/* Unicast */
840 
841 	/*
842 	 * check socket cache ... must talk to Alan about his plans
843 	 * for sock caches... i'll skip this for now.
844 	 */
845 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
846 	if (sk != NULL) {
847 		int ret;
848 
849 		sk_mark_napi_id(sk, skb);
850 		ret = udpv6_queue_rcv_skb(sk, skb);
851 		sock_put(sk);
852 
853 		/* a return value > 0 means to resubmit the input, but
854 		 * it wants the return to be -protocol, or 0
855 		 */
856 		if (ret > 0)
857 			return -ret;
858 
859 		return 0;
860 	}
861 
862 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
863 		goto discard;
864 
865 	if (udp_lib_checksum_complete(skb))
866 		goto csum_error;
867 
868 	UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
869 	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
870 
871 	kfree_skb(skb);
872 	return 0;
873 
874 short_packet:
875 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
876 		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
877 		       saddr,
878 		       ntohs(uh->source),
879 		       ulen,
880 		       skb->len,
881 		       daddr,
882 		       ntohs(uh->dest));
883 	goto discard;
884 csum_error:
885 	UDP6_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
886 discard:
887 	UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
888 	kfree_skb(skb);
889 	return 0;
890 }
891 
892 static __inline__ int udpv6_rcv(struct sk_buff *skb)
893 {
894 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
895 }
896 
897 /*
898  * Throw away all pending data and cancel the corking. Socket is locked.
899  */
900 static void udp_v6_flush_pending_frames(struct sock *sk)
901 {
902 	struct udp_sock *up = udp_sk(sk);
903 
904 	if (up->pending == AF_INET)
905 		udp_flush_pending_frames(sk);
906 	else if (up->pending) {
907 		up->len = 0;
908 		up->pending = 0;
909 		ip6_flush_pending_frames(sk);
910 	}
911 }
912 
913 /**
914  * 	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
915  * 	@sk: 	socket we are sending on
916  * 	@skb: 	sk_buff containing the filled-in UDP header
917  * 	        (checksum field must be zeroed out)
918  */
919 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
920 				 const struct in6_addr *saddr,
921 				 const struct in6_addr *daddr, int len)
922 {
923 	unsigned int offset;
924 	struct udphdr *uh = udp_hdr(skb);
925 	__wsum csum = 0;
926 
927 	if (skb_queue_len(&sk->sk_write_queue) == 1) {
928 		/* Only one fragment on the socket.  */
929 		skb->csum_start = skb_transport_header(skb) - skb->head;
930 		skb->csum_offset = offsetof(struct udphdr, check);
931 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
932 	} else {
933 		/*
934 		 * HW-checksum won't work as there are two or more
935 		 * fragments on the socket so that all csums of sk_buffs
936 		 * should be together
937 		 */
938 		offset = skb_transport_offset(skb);
939 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
940 
941 		skb->ip_summed = CHECKSUM_NONE;
942 
943 		skb_queue_walk(&sk->sk_write_queue, skb) {
944 			csum = csum_add(csum, skb->csum);
945 		}
946 
947 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
948 					    csum);
949 		if (uh->check == 0)
950 			uh->check = CSUM_MANGLED_0;
951 	}
952 }
953 
954 /*
955  *	Sending
956  */
957 
958 static int udp_v6_push_pending_frames(struct sock *sk)
959 {
960 	struct sk_buff *skb;
961 	struct udphdr *uh;
962 	struct udp_sock  *up = udp_sk(sk);
963 	struct inet_sock *inet = inet_sk(sk);
964 	struct flowi6 *fl6;
965 	int err = 0;
966 	int is_udplite = IS_UDPLITE(sk);
967 	__wsum csum = 0;
968 
969 	if (up->pending == AF_INET)
970 		return udp_push_pending_frames(sk);
971 
972 	fl6 = &inet->cork.fl.u.ip6;
973 
974 	/* Grab the skbuff where UDP header space exists. */
975 	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
976 		goto out;
977 
978 	/*
979 	 * Create a UDP header
980 	 */
981 	uh = udp_hdr(skb);
982 	uh->source = fl6->fl6_sport;
983 	uh->dest = fl6->fl6_dport;
984 	uh->len = htons(up->len);
985 	uh->check = 0;
986 
987 	if (is_udplite)
988 		csum = udplite_csum_outgoing(sk, skb);
989 	else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
990 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr,
991 				     up->len);
992 		goto send;
993 	} else
994 		csum = udp_csum_outgoing(sk, skb);
995 
996 	/* add protocol-dependent pseudo-header */
997 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
998 				    up->len, fl6->flowi6_proto, csum);
999 	if (uh->check == 0)
1000 		uh->check = CSUM_MANGLED_0;
1001 
1002 send:
1003 	err = ip6_push_pending_frames(sk);
1004 	if (err) {
1005 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
1006 			UDP6_INC_STATS_USER(sock_net(sk),
1007 					    UDP_MIB_SNDBUFERRORS, is_udplite);
1008 			err = 0;
1009 		}
1010 	} else
1011 		UDP6_INC_STATS_USER(sock_net(sk),
1012 				    UDP_MIB_OUTDATAGRAMS, is_udplite);
1013 out:
1014 	up->len = 0;
1015 	up->pending = 0;
1016 	return err;
1017 }
1018 
1019 int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
1020 		  struct msghdr *msg, size_t len)
1021 {
1022 	struct ipv6_txoptions opt_space;
1023 	struct udp_sock *up = udp_sk(sk);
1024 	struct inet_sock *inet = inet_sk(sk);
1025 	struct ipv6_pinfo *np = inet6_sk(sk);
1026 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
1027 	struct in6_addr *daddr, *final_p, final;
1028 	struct ipv6_txoptions *opt = NULL;
1029 	struct ip6_flowlabel *flowlabel = NULL;
1030 	struct flowi6 fl6;
1031 	struct dst_entry *dst;
1032 	int addr_len = msg->msg_namelen;
1033 	int ulen = len;
1034 	int hlimit = -1;
1035 	int tclass = -1;
1036 	int dontfrag = -1;
1037 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
1038 	int err;
1039 	int connected = 0;
1040 	int is_udplite = IS_UDPLITE(sk);
1041 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
1042 
1043 	/* destination address check */
1044 	if (sin6) {
1045 		if (addr_len < offsetof(struct sockaddr, sa_data))
1046 			return -EINVAL;
1047 
1048 		switch (sin6->sin6_family) {
1049 		case AF_INET6:
1050 			if (addr_len < SIN6_LEN_RFC2133)
1051 				return -EINVAL;
1052 			daddr = &sin6->sin6_addr;
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 = &np->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(iocb, sk, msg, len);
1083 		}
1084 	}
1085 
1086 	if (up->pending == AF_INET)
1087 		return udp_sendmsg(iocb, 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 	if (up->pending) {
1096 		/*
1097 		 * There are pending frames.
1098 		 * The socket lock must be held while it's corked.
1099 		 */
1100 		lock_sock(sk);
1101 		if (likely(up->pending)) {
1102 			if (unlikely(up->pending != AF_INET6)) {
1103 				release_sock(sk);
1104 				return -EAFNOSUPPORT;
1105 			}
1106 			dst = NULL;
1107 			goto do_append_data;
1108 		}
1109 		release_sock(sk);
1110 	}
1111 	ulen += sizeof(struct udphdr);
1112 
1113 	memset(&fl6, 0, sizeof(fl6));
1114 
1115 	if (sin6) {
1116 		if (sin6->sin6_port == 0)
1117 			return -EINVAL;
1118 
1119 		fl6.fl6_dport = sin6->sin6_port;
1120 		daddr = &sin6->sin6_addr;
1121 
1122 		if (np->sndflow) {
1123 			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1124 			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1125 				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1126 				if (flowlabel == NULL)
1127 					return -EINVAL;
1128 				daddr = &flowlabel->dst;
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, &np->daddr))
1138 			daddr = &np->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 = &np->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 
1162 	if (msg->msg_controllen) {
1163 		opt = &opt_space;
1164 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1165 		opt->tot_len = sizeof(*opt);
1166 
1167 		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
1168 					    &hlimit, &tclass, &dontfrag);
1169 		if (err < 0) {
1170 			fl6_sock_release(flowlabel);
1171 			return err;
1172 		}
1173 		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1174 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1175 			if (flowlabel == NULL)
1176 				return -EINVAL;
1177 		}
1178 		if (!(opt->opt_nflen|opt->opt_flen))
1179 			opt = NULL;
1180 		connected = 0;
1181 	}
1182 	if (opt == NULL)
1183 		opt = np->opt;
1184 	if (flowlabel)
1185 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1186 	opt = ipv6_fixup_options(&opt_space, opt);
1187 
1188 	fl6.flowi6_proto = sk->sk_protocol;
1189 	if (!ipv6_addr_any(daddr))
1190 		fl6.daddr = *daddr;
1191 	else
1192 		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1193 	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1194 		fl6.saddr = np->saddr;
1195 	fl6.fl6_sport = inet->inet_sport;
1196 
1197 	final_p = fl6_update_dst(&fl6, opt, &final);
1198 	if (final_p)
1199 		connected = 0;
1200 
1201 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1202 		fl6.flowi6_oif = np->mcast_oif;
1203 		connected = 0;
1204 	} else if (!fl6.flowi6_oif)
1205 		fl6.flowi6_oif = np->ucast_oif;
1206 
1207 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1208 
1209 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p, true);
1210 	if (IS_ERR(dst)) {
1211 		err = PTR_ERR(dst);
1212 		dst = NULL;
1213 		goto out;
1214 	}
1215 
1216 	if (hlimit < 0) {
1217 		if (ipv6_addr_is_multicast(&fl6.daddr))
1218 			hlimit = np->mcast_hops;
1219 		else
1220 			hlimit = np->hop_limit;
1221 		if (hlimit < 0)
1222 			hlimit = ip6_dst_hoplimit(dst);
1223 	}
1224 
1225 	if (tclass < 0)
1226 		tclass = np->tclass;
1227 
1228 	if (dontfrag < 0)
1229 		dontfrag = np->dontfrag;
1230 
1231 	if (msg->msg_flags&MSG_CONFIRM)
1232 		goto do_confirm;
1233 back_from_confirm:
1234 
1235 	lock_sock(sk);
1236 	if (unlikely(up->pending)) {
1237 		/* The socket is already corked while preparing it. */
1238 		/* ... which is an evident application bug. --ANK */
1239 		release_sock(sk);
1240 
1241 		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
1242 		err = -EINVAL;
1243 		goto out;
1244 	}
1245 
1246 	up->pending = AF_INET6;
1247 
1248 do_append_data:
1249 	up->len += ulen;
1250 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1251 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
1252 		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
1253 		(struct rt6_info*)dst,
1254 		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
1255 	if (err)
1256 		udp_v6_flush_pending_frames(sk);
1257 	else if (!corkreq)
1258 		err = udp_v6_push_pending_frames(sk);
1259 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1260 		up->pending = 0;
1261 
1262 	if (dst) {
1263 		if (connected) {
1264 			ip6_dst_store(sk, dst,
1265 				      ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
1266 				      &np->daddr : NULL,
1267 #ifdef CONFIG_IPV6_SUBTREES
1268 				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1269 				      &np->saddr :
1270 #endif
1271 				      NULL);
1272 		} else {
1273 			dst_release(dst);
1274 		}
1275 		dst = NULL;
1276 	}
1277 
1278 	if (err > 0)
1279 		err = np->recverr ? net_xmit_errno(err) : 0;
1280 	release_sock(sk);
1281 out:
1282 	dst_release(dst);
1283 	fl6_sock_release(flowlabel);
1284 	if (!err)
1285 		return len;
1286 	/*
1287 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1288 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1289 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1290 	 * things).  We could add another new stat but at least for now that
1291 	 * seems like overkill.
1292 	 */
1293 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1294 		UDP6_INC_STATS_USER(sock_net(sk),
1295 				UDP_MIB_SNDBUFERRORS, is_udplite);
1296 	}
1297 	return err;
1298 
1299 do_confirm:
1300 	dst_confirm(dst);
1301 	if (!(msg->msg_flags&MSG_PROBE) || len)
1302 		goto back_from_confirm;
1303 	err = 0;
1304 	goto out;
1305 }
1306 
1307 void udpv6_destroy_sock(struct sock *sk)
1308 {
1309 	struct udp_sock *up = udp_sk(sk);
1310 	lock_sock(sk);
1311 	udp_v6_flush_pending_frames(sk);
1312 	release_sock(sk);
1313 
1314 	if (static_key_false(&udpv6_encap_needed) && up->encap_type) {
1315 		void (*encap_destroy)(struct sock *sk);
1316 		encap_destroy = ACCESS_ONCE(up->encap_destroy);
1317 		if (encap_destroy)
1318 			encap_destroy(sk);
1319 	}
1320 
1321 	inet6_destroy_sock(sk);
1322 }
1323 
1324 /*
1325  *	Socket option code for UDP
1326  */
1327 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1328 		     char __user *optval, unsigned int optlen)
1329 {
1330 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1331 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1332 					  udp_v6_push_pending_frames);
1333 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1334 }
1335 
1336 #ifdef CONFIG_COMPAT
1337 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1338 			    char __user *optval, unsigned int optlen)
1339 {
1340 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1341 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1342 					  udp_v6_push_pending_frames);
1343 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1344 }
1345 #endif
1346 
1347 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1348 		     char __user *optval, int __user *optlen)
1349 {
1350 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1351 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1352 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1353 }
1354 
1355 #ifdef CONFIG_COMPAT
1356 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1357 			    char __user *optval, int __user *optlen)
1358 {
1359 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1360 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1361 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1362 }
1363 #endif
1364 
1365 static const struct inet6_protocol udpv6_protocol = {
1366 	.handler	=	udpv6_rcv,
1367 	.err_handler	=	udpv6_err,
1368 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1369 };
1370 
1371 /* ------------------------------------------------------------------------ */
1372 #ifdef CONFIG_PROC_FS
1373 int udp6_seq_show(struct seq_file *seq, void *v)
1374 {
1375 	if (v == SEQ_START_TOKEN) {
1376 		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
1377 	} else {
1378 		int bucket = ((struct udp_iter_state *)seq->private)->bucket;
1379 		struct inet_sock *inet = inet_sk(v);
1380 		__u16 srcp = ntohs(inet->inet_sport);
1381 		__u16 destp = ntohs(inet->inet_dport);
1382 		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
1383 	}
1384 	return 0;
1385 }
1386 
1387 static const struct file_operations udp6_afinfo_seq_fops = {
1388 	.owner    = THIS_MODULE,
1389 	.open     = udp_seq_open,
1390 	.read     = seq_read,
1391 	.llseek   = seq_lseek,
1392 	.release  = seq_release_net
1393 };
1394 
1395 static struct udp_seq_afinfo udp6_seq_afinfo = {
1396 	.name		= "udp6",
1397 	.family		= AF_INET6,
1398 	.udp_table	= &udp_table,
1399 	.seq_fops	= &udp6_afinfo_seq_fops,
1400 	.seq_ops	= {
1401 		.show		= udp6_seq_show,
1402 	},
1403 };
1404 
1405 int __net_init udp6_proc_init(struct net *net)
1406 {
1407 	return udp_proc_register(net, &udp6_seq_afinfo);
1408 }
1409 
1410 void udp6_proc_exit(struct net *net) {
1411 	udp_proc_unregister(net, &udp6_seq_afinfo);
1412 }
1413 #endif /* CONFIG_PROC_FS */
1414 
1415 void udp_v6_clear_sk(struct sock *sk, int size)
1416 {
1417 	struct inet_sock *inet = inet_sk(sk);
1418 
1419 	/* we do not want to clear pinet6 field, because of RCU lookups */
1420 	sk_prot_clear_portaddr_nulls(sk, offsetof(struct inet_sock, pinet6));
1421 
1422 	size -= offsetof(struct inet_sock, pinet6) + sizeof(inet->pinet6);
1423 	memset(&inet->pinet6 + 1, 0, size);
1424 }
1425 
1426 /* ------------------------------------------------------------------------ */
1427 
1428 struct proto udpv6_prot = {
1429 	.name		   = "UDPv6",
1430 	.owner		   = THIS_MODULE,
1431 	.close		   = udp_lib_close,
1432 	.connect	   = ip6_datagram_connect,
1433 	.disconnect	   = udp_disconnect,
1434 	.ioctl		   = udp_ioctl,
1435 	.destroy	   = udpv6_destroy_sock,
1436 	.setsockopt	   = udpv6_setsockopt,
1437 	.getsockopt	   = udpv6_getsockopt,
1438 	.sendmsg	   = udpv6_sendmsg,
1439 	.recvmsg	   = udpv6_recvmsg,
1440 	.backlog_rcv	   = __udpv6_queue_rcv_skb,
1441 	.hash		   = udp_lib_hash,
1442 	.unhash		   = udp_lib_unhash,
1443 	.rehash		   = udp_v6_rehash,
1444 	.get_port	   = udp_v6_get_port,
1445 	.memory_allocated  = &udp_memory_allocated,
1446 	.sysctl_mem	   = sysctl_udp_mem,
1447 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1448 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1449 	.obj_size	   = sizeof(struct udp6_sock),
1450 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1451 	.h.udp_table	   = &udp_table,
1452 #ifdef CONFIG_COMPAT
1453 	.compat_setsockopt = compat_udpv6_setsockopt,
1454 	.compat_getsockopt = compat_udpv6_getsockopt,
1455 #endif
1456 	.clear_sk	   = udp_v6_clear_sk,
1457 };
1458 
1459 static struct inet_protosw udpv6_protosw = {
1460 	.type =      SOCK_DGRAM,
1461 	.protocol =  IPPROTO_UDP,
1462 	.prot =      &udpv6_prot,
1463 	.ops =       &inet6_dgram_ops,
1464 	.no_check =  UDP_CSUM_DEFAULT,
1465 	.flags =     INET_PROTOSW_PERMANENT,
1466 };
1467 
1468 
1469 int __init udpv6_init(void)
1470 {
1471 	int ret;
1472 
1473 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1474 	if (ret)
1475 		goto out;
1476 
1477 	ret = inet6_register_protosw(&udpv6_protosw);
1478 	if (ret)
1479 		goto out_udpv6_protocol;
1480 out:
1481 	return ret;
1482 
1483 out_udpv6_protocol:
1484 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1485 	goto out;
1486 }
1487 
1488 void udpv6_exit(void)
1489 {
1490 	inet6_unregister_protosw(&udpv6_protosw);
1491 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1492 }
1493