xref: /openbmc/linux/net/ipv6/udp.c (revision a09d2831)
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 <asm/uaccess.h>
38 
39 #include <net/ndisc.h>
40 #include <net/protocol.h>
41 #include <net/transp_v6.h>
42 #include <net/ip6_route.h>
43 #include <net/raw.h>
44 #include <net/tcp_states.h>
45 #include <net/ip6_checksum.h>
46 #include <net/xfrm.h>
47 
48 #include <linux/proc_fs.h>
49 #include <linux/seq_file.h>
50 #include "udp_impl.h"
51 
52 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
53 {
54 	const struct in6_addr *sk_rcv_saddr6 = &inet6_sk(sk)->rcv_saddr;
55 	const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
56 	__be32 sk1_rcv_saddr = inet_sk(sk)->inet_rcv_saddr;
57 	__be32 sk2_rcv_saddr = inet_rcv_saddr(sk2);
58 	int sk_ipv6only = ipv6_only_sock(sk);
59 	int sk2_ipv6only = inet_v6_ipv6only(sk2);
60 	int addr_type = ipv6_addr_type(sk_rcv_saddr6);
61 	int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
62 
63 	/* if both are mapped, treat as IPv4 */
64 	if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED)
65 		return (!sk2_ipv6only &&
66 			(!sk1_rcv_saddr || !sk2_rcv_saddr ||
67 			  sk1_rcv_saddr == sk2_rcv_saddr));
68 
69 	if (addr_type2 == IPV6_ADDR_ANY &&
70 	    !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
71 		return 1;
72 
73 	if (addr_type == IPV6_ADDR_ANY &&
74 	    !(sk_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
75 		return 1;
76 
77 	if (sk2_rcv_saddr6 &&
78 	    ipv6_addr_equal(sk_rcv_saddr6, sk2_rcv_saddr6))
79 		return 1;
80 
81 	return 0;
82 }
83 
84 static unsigned int udp6_portaddr_hash(struct net *net,
85 				       const struct in6_addr *addr6,
86 				       unsigned int port)
87 {
88 	unsigned int hash, mix = net_hash_mix(net);
89 
90 	if (ipv6_addr_any(addr6))
91 		hash = jhash_1word(0, mix);
92 	else if (ipv6_addr_v4mapped(addr6))
93 		hash = jhash_1word(addr6->s6_addr32[3], mix);
94 	else
95 		hash = jhash2(addr6->s6_addr32, 4, mix);
96 
97 	return hash ^ port;
98 }
99 
100 
101 int udp_v6_get_port(struct sock *sk, unsigned short snum)
102 {
103 	unsigned int hash2_nulladdr =
104 		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
105 	unsigned int hash2_partial =
106 		udp6_portaddr_hash(sock_net(sk), &inet6_sk(sk)->rcv_saddr, 0);
107 
108 	/* precompute partial secondary hash */
109 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
110 	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
111 }
112 
113 static inline int compute_score(struct sock *sk, struct net *net,
114 				unsigned short hnum,
115 				struct in6_addr *saddr, __be16 sport,
116 				struct in6_addr *daddr, __be16 dport,
117 				int dif)
118 {
119 	int score = -1;
120 
121 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
122 			sk->sk_family == PF_INET6) {
123 		struct ipv6_pinfo *np = inet6_sk(sk);
124 		struct inet_sock *inet = inet_sk(sk);
125 
126 		score = 0;
127 		if (inet->inet_dport) {
128 			if (inet->inet_dport != sport)
129 				return -1;
130 			score++;
131 		}
132 		if (!ipv6_addr_any(&np->rcv_saddr)) {
133 			if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
134 				return -1;
135 			score++;
136 		}
137 		if (!ipv6_addr_any(&np->daddr)) {
138 			if (!ipv6_addr_equal(&np->daddr, saddr))
139 				return -1;
140 			score++;
141 		}
142 		if (sk->sk_bound_dev_if) {
143 			if (sk->sk_bound_dev_if != dif)
144 				return -1;
145 			score++;
146 		}
147 	}
148 	return score;
149 }
150 
151 #define SCORE2_MAX (1 + 1 + 1)
152 static inline int compute_score2(struct sock *sk, struct net *net,
153 				const struct in6_addr *saddr, __be16 sport,
154 				const struct in6_addr *daddr, unsigned short hnum,
155 				int dif)
156 {
157 	int score = -1;
158 
159 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
160 			sk->sk_family == PF_INET6) {
161 		struct ipv6_pinfo *np = inet6_sk(sk);
162 		struct inet_sock *inet = inet_sk(sk);
163 
164 		if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
165 			return -1;
166 		score = 0;
167 		if (inet->inet_dport) {
168 			if (inet->inet_dport != sport)
169 				return -1;
170 			score++;
171 		}
172 		if (!ipv6_addr_any(&np->daddr)) {
173 			if (!ipv6_addr_equal(&np->daddr, saddr))
174 				return -1;
175 			score++;
176 		}
177 		if (sk->sk_bound_dev_if) {
178 			if (sk->sk_bound_dev_if != dif)
179 				return -1;
180 			score++;
181 		}
182 	}
183 	return score;
184 }
185 
186 
187 /* called with read_rcu_lock() */
188 static struct sock *udp6_lib_lookup2(struct net *net,
189 		const struct in6_addr *saddr, __be16 sport,
190 		const struct in6_addr *daddr, unsigned int hnum, int dif,
191 		struct udp_hslot *hslot2, unsigned int slot2)
192 {
193 	struct sock *sk, *result;
194 	struct hlist_nulls_node *node;
195 	int score, badness;
196 
197 begin:
198 	result = NULL;
199 	badness = -1;
200 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
201 		score = compute_score2(sk, net, saddr, sport,
202 				      daddr, hnum, dif);
203 		if (score > badness) {
204 			result = sk;
205 			badness = score;
206 			if (score == SCORE2_MAX)
207 				goto exact_match;
208 		}
209 	}
210 	/*
211 	 * if the nulls value we got at the end of this lookup is
212 	 * not the expected one, we must restart lookup.
213 	 * We probably met an item that was moved to another chain.
214 	 */
215 	if (get_nulls_value(node) != slot2)
216 		goto begin;
217 
218 	if (result) {
219 exact_match:
220 		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
221 			result = NULL;
222 		else if (unlikely(compute_score2(result, net, saddr, sport,
223 				  daddr, hnum, dif) < badness)) {
224 			sock_put(result);
225 			goto begin;
226 		}
227 	}
228 	return result;
229 }
230 
231 static struct sock *__udp6_lib_lookup(struct net *net,
232 				      struct in6_addr *saddr, __be16 sport,
233 				      struct in6_addr *daddr, __be16 dport,
234 				      int dif, struct udp_table *udptable)
235 {
236 	struct sock *sk, *result;
237 	struct hlist_nulls_node *node;
238 	unsigned short hnum = ntohs(dport);
239 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
240 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
241 	int score, badness;
242 
243 	rcu_read_lock();
244 	if (hslot->count > 10) {
245 		hash2 = udp6_portaddr_hash(net, daddr, hnum);
246 		slot2 = hash2 & udptable->mask;
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 					  hslot2, slot2);
254 		if (!result) {
255 			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
256 			slot2 = hash2 & udptable->mask;
257 			hslot2 = &udptable->hash2[slot2];
258 			if (hslot->count < hslot2->count)
259 				goto begin;
260 
261 			result = udp6_lib_lookup2(net, &in6addr_any, sport,
262 						  daddr, hnum, dif,
263 						  hslot2, slot2);
264 		}
265 		rcu_read_unlock();
266 		return result;
267 	}
268 begin:
269 	result = NULL;
270 	badness = -1;
271 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
272 		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
273 		if (score > badness) {
274 			result = sk;
275 			badness = score;
276 		}
277 	}
278 	/*
279 	 * if the nulls value we got at the end of this lookup is
280 	 * not the expected one, we must restart lookup.
281 	 * We probably met an item that was moved to another chain.
282 	 */
283 	if (get_nulls_value(node) != slot)
284 		goto begin;
285 
286 	if (result) {
287 		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
288 			result = NULL;
289 		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
290 					daddr, dport, dif) < badness)) {
291 			sock_put(result);
292 			goto begin;
293 		}
294 	}
295 	rcu_read_unlock();
296 	return result;
297 }
298 
299 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
300 					  __be16 sport, __be16 dport,
301 					  struct udp_table *udptable)
302 {
303 	struct sock *sk;
304 	struct ipv6hdr *iph = ipv6_hdr(skb);
305 
306 	if (unlikely(sk = skb_steal_sock(skb)))
307 		return sk;
308 	return __udp6_lib_lookup(dev_net(skb_dst(skb)->dev), &iph->saddr, sport,
309 				 &iph->daddr, dport, inet6_iif(skb),
310 				 udptable);
311 }
312 
313 /*
314  * 	This should be easy, if there is something there we
315  * 	return it, otherwise we block.
316  */
317 
318 int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
319 		  struct msghdr *msg, size_t len,
320 		  int noblock, int flags, int *addr_len)
321 {
322 	struct ipv6_pinfo *np = inet6_sk(sk);
323 	struct inet_sock *inet = inet_sk(sk);
324 	struct sk_buff *skb;
325 	unsigned int ulen, copied;
326 	int peeked;
327 	int err;
328 	int is_udplite = IS_UDPLITE(sk);
329 	int is_udp4;
330 
331 	if (addr_len)
332 		*addr_len=sizeof(struct sockaddr_in6);
333 
334 	if (flags & MSG_ERRQUEUE)
335 		return ipv6_recv_error(sk, msg, len);
336 
337 try_again:
338 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
339 				  &peeked, &err);
340 	if (!skb)
341 		goto out;
342 
343 	ulen = skb->len - sizeof(struct udphdr);
344 	copied = len;
345 	if (copied > ulen)
346 		copied = ulen;
347 	else if (copied < ulen)
348 		msg->msg_flags |= MSG_TRUNC;
349 
350 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
351 
352 	/*
353 	 * If checksum is needed at all, try to do it while copying the
354 	 * data.  If the data is truncated, or if we only want a partial
355 	 * coverage checksum (UDP-Lite), do it before the copy.
356 	 */
357 
358 	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
359 		if (udp_lib_checksum_complete(skb))
360 			goto csum_copy_err;
361 	}
362 
363 	if (skb_csum_unnecessary(skb))
364 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
365 					      msg->msg_iov, copied       );
366 	else {
367 		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
368 		if (err == -EINVAL)
369 			goto csum_copy_err;
370 	}
371 	if (err)
372 		goto out_free;
373 
374 	if (!peeked) {
375 		if (is_udp4)
376 			UDP_INC_STATS_USER(sock_net(sk),
377 					UDP_MIB_INDATAGRAMS, is_udplite);
378 		else
379 			UDP6_INC_STATS_USER(sock_net(sk),
380 					UDP_MIB_INDATAGRAMS, is_udplite);
381 	}
382 
383 	sock_recv_ts_and_drops(msg, sk, skb);
384 
385 	/* Copy the address. */
386 	if (msg->msg_name) {
387 		struct sockaddr_in6 *sin6;
388 
389 		sin6 = (struct sockaddr_in6 *) msg->msg_name;
390 		sin6->sin6_family = AF_INET6;
391 		sin6->sin6_port = udp_hdr(skb)->source;
392 		sin6->sin6_flowinfo = 0;
393 		sin6->sin6_scope_id = 0;
394 
395 		if (is_udp4)
396 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
397 					       &sin6->sin6_addr);
398 		else {
399 			ipv6_addr_copy(&sin6->sin6_addr,
400 				       &ipv6_hdr(skb)->saddr);
401 			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
402 				sin6->sin6_scope_id = IP6CB(skb)->iif;
403 		}
404 
405 	}
406 	if (is_udp4) {
407 		if (inet->cmsg_flags)
408 			ip_cmsg_recv(msg, skb);
409 	} else {
410 		if (np->rxopt.all)
411 			datagram_recv_ctl(sk, msg, skb);
412 	}
413 
414 	err = copied;
415 	if (flags & MSG_TRUNC)
416 		err = ulen;
417 
418 out_free:
419 	skb_free_datagram_locked(sk, skb);
420 out:
421 	return err;
422 
423 csum_copy_err:
424 	lock_sock(sk);
425 	if (!skb_kill_datagram(sk, skb, flags)) {
426 		if (is_udp4)
427 			UDP_INC_STATS_USER(sock_net(sk),
428 					UDP_MIB_INERRORS, is_udplite);
429 		else
430 			UDP6_INC_STATS_USER(sock_net(sk),
431 					UDP_MIB_INERRORS, is_udplite);
432 	}
433 	release_sock(sk);
434 
435 	if (flags & MSG_DONTWAIT)
436 		return -EAGAIN;
437 	goto try_again;
438 }
439 
440 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
441 		    u8 type, u8 code, int offset, __be32 info,
442 		    struct udp_table *udptable)
443 {
444 	struct ipv6_pinfo *np;
445 	struct ipv6hdr *hdr = (struct ipv6hdr*)skb->data;
446 	struct in6_addr *saddr = &hdr->saddr;
447 	struct in6_addr *daddr = &hdr->daddr;
448 	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
449 	struct sock *sk;
450 	int err;
451 
452 	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
453 			       saddr, uh->source, inet6_iif(skb), udptable);
454 	if (sk == NULL)
455 		return;
456 
457 	np = inet6_sk(sk);
458 
459 	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
460 		goto out;
461 
462 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
463 		goto out;
464 
465 	if (np->recverr)
466 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
467 
468 	sk->sk_err = err;
469 	sk->sk_error_report(sk);
470 out:
471 	sock_put(sk);
472 }
473 
474 static __inline__ void udpv6_err(struct sk_buff *skb,
475 				 struct inet6_skb_parm *opt, u8 type,
476 				 u8 code, int offset, __be32 info     )
477 {
478 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
479 }
480 
481 int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
482 {
483 	struct udp_sock *up = udp_sk(sk);
484 	int rc;
485 	int is_udplite = IS_UDPLITE(sk);
486 
487 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
488 		goto drop;
489 
490 	/*
491 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
492 	 */
493 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
494 
495 		if (up->pcrlen == 0) {          /* full coverage was set  */
496 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
497 				" %d while full coverage %d requested\n",
498 				UDP_SKB_CB(skb)->cscov, skb->len);
499 			goto drop;
500 		}
501 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
502 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
503 						    "too small, need min %d\n",
504 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
505 			goto drop;
506 		}
507 	}
508 
509 	if (sk->sk_filter) {
510 		if (udp_lib_checksum_complete(skb))
511 			goto drop;
512 	}
513 
514 	if ((rc = sock_queue_rcv_skb(sk, skb)) < 0) {
515 		/* Note that an ENOMEM error is charged twice */
516 		if (rc == -ENOMEM)
517 			UDP6_INC_STATS_BH(sock_net(sk),
518 					UDP_MIB_RCVBUFERRORS, is_udplite);
519 		goto drop_no_sk_drops_inc;
520 	}
521 
522 	return 0;
523 drop:
524 	atomic_inc(&sk->sk_drops);
525 drop_no_sk_drops_inc:
526 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
527 	kfree_skb(skb);
528 	return -1;
529 }
530 
531 static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
532 				      __be16 loc_port, struct in6_addr *loc_addr,
533 				      __be16 rmt_port, struct in6_addr *rmt_addr,
534 				      int dif)
535 {
536 	struct hlist_nulls_node *node;
537 	struct sock *s = sk;
538 	unsigned short num = ntohs(loc_port);
539 
540 	sk_nulls_for_each_from(s, node) {
541 		struct inet_sock *inet = inet_sk(s);
542 
543 		if (!net_eq(sock_net(s), net))
544 			continue;
545 
546 		if (udp_sk(s)->udp_port_hash == num &&
547 		    s->sk_family == PF_INET6) {
548 			struct ipv6_pinfo *np = inet6_sk(s);
549 			if (inet->inet_dport) {
550 				if (inet->inet_dport != rmt_port)
551 					continue;
552 			}
553 			if (!ipv6_addr_any(&np->daddr) &&
554 			    !ipv6_addr_equal(&np->daddr, rmt_addr))
555 				continue;
556 
557 			if (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)
558 				continue;
559 
560 			if (!ipv6_addr_any(&np->rcv_saddr)) {
561 				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
562 					continue;
563 			}
564 			if (!inet6_mc_check(s, loc_addr, rmt_addr))
565 				continue;
566 			return s;
567 		}
568 	}
569 	return NULL;
570 }
571 
572 static void flush_stack(struct sock **stack, unsigned int count,
573 			struct sk_buff *skb, unsigned int final)
574 {
575 	unsigned int i;
576 	struct sock *sk;
577 	struct sk_buff *skb1;
578 
579 	for (i = 0; i < count; i++) {
580 		skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
581 
582 		sk = stack[i];
583 		if (skb1) {
584 			bh_lock_sock(sk);
585 			if (!sock_owned_by_user(sk))
586 				udpv6_queue_rcv_skb(sk, skb1);
587 			else
588 				sk_add_backlog(sk, skb1);
589 			bh_unlock_sock(sk);
590 		} else {
591 			atomic_inc(&sk->sk_drops);
592 			UDP6_INC_STATS_BH(sock_net(sk),
593 					UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
594 			UDP6_INC_STATS_BH(sock_net(sk),
595 					UDP_MIB_INERRORS, IS_UDPLITE(sk));
596 		}
597 	}
598 }
599 /*
600  * Note: called only from the BH handler context,
601  * so we don't need to lock the hashes.
602  */
603 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
604 		struct in6_addr *saddr, struct in6_addr *daddr,
605 		struct udp_table *udptable)
606 {
607 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
608 	const struct udphdr *uh = udp_hdr(skb);
609 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
610 	int dif;
611 	unsigned int i, count = 0;
612 
613 	spin_lock(&hslot->lock);
614 	sk = sk_nulls_head(&hslot->head);
615 	dif = inet6_iif(skb);
616 	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
617 	while (sk) {
618 		stack[count++] = sk;
619 		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
620 				       uh->source, saddr, dif);
621 		if (unlikely(count == ARRAY_SIZE(stack))) {
622 			if (!sk)
623 				break;
624 			flush_stack(stack, count, skb, ~0);
625 			count = 0;
626 		}
627 	}
628 	/*
629 	 * before releasing the lock, we must take reference on sockets
630 	 */
631 	for (i = 0; i < count; i++)
632 		sock_hold(stack[i]);
633 
634 	spin_unlock(&hslot->lock);
635 
636 	if (count) {
637 		flush_stack(stack, count, skb, count - 1);
638 
639 		for (i = 0; i < count; i++)
640 			sock_put(stack[i]);
641 	} else {
642 		kfree_skb(skb);
643 	}
644 	return 0;
645 }
646 
647 static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
648 				 int proto)
649 {
650 	int err;
651 
652 	UDP_SKB_CB(skb)->partial_cov = 0;
653 	UDP_SKB_CB(skb)->cscov = skb->len;
654 
655 	if (proto == IPPROTO_UDPLITE) {
656 		err = udplite_checksum_init(skb, uh);
657 		if (err)
658 			return err;
659 	}
660 
661 	if (uh->check == 0) {
662 		/* RFC 2460 section 8.1 says that we SHOULD log
663 		   this error. Well, it is reasonable.
664 		 */
665 		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0\n");
666 		return 1;
667 	}
668 	if (skb->ip_summed == CHECKSUM_COMPLETE &&
669 	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
670 			     skb->len, proto, skb->csum))
671 		skb->ip_summed = CHECKSUM_UNNECESSARY;
672 
673 	if (!skb_csum_unnecessary(skb))
674 		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
675 							 &ipv6_hdr(skb)->daddr,
676 							 skb->len, proto, 0));
677 
678 	return 0;
679 }
680 
681 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
682 		   int proto)
683 {
684 	struct sock *sk;
685 	struct udphdr *uh;
686 	struct net_device *dev = skb->dev;
687 	struct in6_addr *saddr, *daddr;
688 	u32 ulen = 0;
689 	struct net *net = dev_net(skb->dev);
690 
691 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
692 		goto short_packet;
693 
694 	saddr = &ipv6_hdr(skb)->saddr;
695 	daddr = &ipv6_hdr(skb)->daddr;
696 	uh = udp_hdr(skb);
697 
698 	ulen = ntohs(uh->len);
699 	if (ulen > skb->len)
700 		goto short_packet;
701 
702 	if (proto == IPPROTO_UDP) {
703 		/* UDP validates ulen. */
704 
705 		/* Check for jumbo payload */
706 		if (ulen == 0)
707 			ulen = skb->len;
708 
709 		if (ulen < sizeof(*uh))
710 			goto short_packet;
711 
712 		if (ulen < skb->len) {
713 			if (pskb_trim_rcsum(skb, ulen))
714 				goto short_packet;
715 			saddr = &ipv6_hdr(skb)->saddr;
716 			daddr = &ipv6_hdr(skb)->daddr;
717 			uh = udp_hdr(skb);
718 		}
719 	}
720 
721 	if (udp6_csum_init(skb, uh, proto))
722 		goto discard;
723 
724 	/*
725 	 *	Multicast receive code
726 	 */
727 	if (ipv6_addr_is_multicast(daddr))
728 		return __udp6_lib_mcast_deliver(net, skb,
729 				saddr, daddr, udptable);
730 
731 	/* Unicast */
732 
733 	/*
734 	 * check socket cache ... must talk to Alan about his plans
735 	 * for sock caches... i'll skip this for now.
736 	 */
737 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
738 
739 	if (sk == NULL) {
740 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
741 			goto discard;
742 
743 		if (udp_lib_checksum_complete(skb))
744 			goto discard;
745 		UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS,
746 				proto == IPPROTO_UDPLITE);
747 
748 		icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0, dev);
749 
750 		kfree_skb(skb);
751 		return 0;
752 	}
753 
754 	/* deliver */
755 
756 	bh_lock_sock(sk);
757 	if (!sock_owned_by_user(sk))
758 		udpv6_queue_rcv_skb(sk, skb);
759 	else
760 		sk_add_backlog(sk, skb);
761 	bh_unlock_sock(sk);
762 	sock_put(sk);
763 	return 0;
764 
765 short_packet:
766 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: %d/%u\n",
767 		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
768 		       ulen, skb->len);
769 
770 discard:
771 	UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
772 	kfree_skb(skb);
773 	return 0;
774 }
775 
776 static __inline__ int udpv6_rcv(struct sk_buff *skb)
777 {
778 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
779 }
780 
781 /*
782  * Throw away all pending data and cancel the corking. Socket is locked.
783  */
784 static void udp_v6_flush_pending_frames(struct sock *sk)
785 {
786 	struct udp_sock *up = udp_sk(sk);
787 
788 	if (up->pending == AF_INET)
789 		udp_flush_pending_frames(sk);
790 	else if (up->pending) {
791 		up->len = 0;
792 		up->pending = 0;
793 		ip6_flush_pending_frames(sk);
794 	}
795 }
796 
797 /**
798  * 	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
799  * 	@sk: 	socket we are sending on
800  * 	@skb: 	sk_buff containing the filled-in UDP header
801  * 	        (checksum field must be zeroed out)
802  */
803 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
804 				 const struct in6_addr *saddr,
805 				 const struct in6_addr *daddr, int len)
806 {
807 	unsigned int offset;
808 	struct udphdr *uh = udp_hdr(skb);
809 	__wsum csum = 0;
810 
811 	if (skb_queue_len(&sk->sk_write_queue) == 1) {
812 		/* Only one fragment on the socket.  */
813 		skb->csum_start = skb_transport_header(skb) - skb->head;
814 		skb->csum_offset = offsetof(struct udphdr, check);
815 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
816 	} else {
817 		/*
818 		 * HW-checksum won't work as there are two or more
819 		 * fragments on the socket so that all csums of sk_buffs
820 		 * should be together
821 		 */
822 		offset = skb_transport_offset(skb);
823 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
824 
825 		skb->ip_summed = CHECKSUM_NONE;
826 
827 		skb_queue_walk(&sk->sk_write_queue, skb) {
828 			csum = csum_add(csum, skb->csum);
829 		}
830 
831 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
832 					    csum);
833 		if (uh->check == 0)
834 			uh->check = CSUM_MANGLED_0;
835 	}
836 }
837 
838 /*
839  *	Sending
840  */
841 
842 static int udp_v6_push_pending_frames(struct sock *sk)
843 {
844 	struct sk_buff *skb;
845 	struct udphdr *uh;
846 	struct udp_sock  *up = udp_sk(sk);
847 	struct inet_sock *inet = inet_sk(sk);
848 	struct flowi *fl = &inet->cork.fl;
849 	int err = 0;
850 	int is_udplite = IS_UDPLITE(sk);
851 	__wsum csum = 0;
852 
853 	/* Grab the skbuff where UDP header space exists. */
854 	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
855 		goto out;
856 
857 	/*
858 	 * Create a UDP header
859 	 */
860 	uh = udp_hdr(skb);
861 	uh->source = fl->fl_ip_sport;
862 	uh->dest = fl->fl_ip_dport;
863 	uh->len = htons(up->len);
864 	uh->check = 0;
865 
866 	if (is_udplite)
867 		csum = udplite_csum_outgoing(sk, skb);
868 	else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
869 		udp6_hwcsum_outgoing(sk, skb, &fl->fl6_src, &fl->fl6_dst,
870 				     up->len);
871 		goto send;
872 	} else
873 		csum = udp_csum_outgoing(sk, skb);
874 
875 	/* add protocol-dependent pseudo-header */
876 	uh->check = csum_ipv6_magic(&fl->fl6_src, &fl->fl6_dst,
877 				    up->len, fl->proto, csum   );
878 	if (uh->check == 0)
879 		uh->check = CSUM_MANGLED_0;
880 
881 send:
882 	err = ip6_push_pending_frames(sk);
883 	if (err) {
884 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
885 			UDP6_INC_STATS_USER(sock_net(sk),
886 					    UDP_MIB_SNDBUFERRORS, is_udplite);
887 			err = 0;
888 		}
889 	} else
890 		UDP6_INC_STATS_USER(sock_net(sk),
891 				    UDP_MIB_OUTDATAGRAMS, is_udplite);
892 out:
893 	up->len = 0;
894 	up->pending = 0;
895 	return err;
896 }
897 
898 int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
899 		  struct msghdr *msg, size_t len)
900 {
901 	struct ipv6_txoptions opt_space;
902 	struct udp_sock *up = udp_sk(sk);
903 	struct inet_sock *inet = inet_sk(sk);
904 	struct ipv6_pinfo *np = inet6_sk(sk);
905 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
906 	struct in6_addr *daddr, *final_p = NULL, final;
907 	struct ipv6_txoptions *opt = NULL;
908 	struct ip6_flowlabel *flowlabel = NULL;
909 	struct flowi fl;
910 	struct dst_entry *dst;
911 	int addr_len = msg->msg_namelen;
912 	int ulen = len;
913 	int hlimit = -1;
914 	int tclass = -1;
915 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
916 	int err;
917 	int connected = 0;
918 	int is_udplite = IS_UDPLITE(sk);
919 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
920 
921 	/* destination address check */
922 	if (sin6) {
923 		if (addr_len < offsetof(struct sockaddr, sa_data))
924 			return -EINVAL;
925 
926 		switch (sin6->sin6_family) {
927 		case AF_INET6:
928 			if (addr_len < SIN6_LEN_RFC2133)
929 				return -EINVAL;
930 			daddr = &sin6->sin6_addr;
931 			break;
932 		case AF_INET:
933 			goto do_udp_sendmsg;
934 		case AF_UNSPEC:
935 			msg->msg_name = sin6 = NULL;
936 			msg->msg_namelen = addr_len = 0;
937 			daddr = NULL;
938 			break;
939 		default:
940 			return -EINVAL;
941 		}
942 	} else if (!up->pending) {
943 		if (sk->sk_state != TCP_ESTABLISHED)
944 			return -EDESTADDRREQ;
945 		daddr = &np->daddr;
946 	} else
947 		daddr = NULL;
948 
949 	if (daddr) {
950 		if (ipv6_addr_v4mapped(daddr)) {
951 			struct sockaddr_in sin;
952 			sin.sin_family = AF_INET;
953 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
954 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
955 			msg->msg_name = &sin;
956 			msg->msg_namelen = sizeof(sin);
957 do_udp_sendmsg:
958 			if (__ipv6_only_sock(sk))
959 				return -ENETUNREACH;
960 			return udp_sendmsg(iocb, sk, msg, len);
961 		}
962 	}
963 
964 	if (up->pending == AF_INET)
965 		return udp_sendmsg(iocb, sk, msg, len);
966 
967 	/* Rough check on arithmetic overflow,
968 	   better check is made in ip6_append_data().
969 	   */
970 	if (len > INT_MAX - sizeof(struct udphdr))
971 		return -EMSGSIZE;
972 
973 	if (up->pending) {
974 		/*
975 		 * There are pending frames.
976 		 * The socket lock must be held while it's corked.
977 		 */
978 		lock_sock(sk);
979 		if (likely(up->pending)) {
980 			if (unlikely(up->pending != AF_INET6)) {
981 				release_sock(sk);
982 				return -EAFNOSUPPORT;
983 			}
984 			dst = NULL;
985 			goto do_append_data;
986 		}
987 		release_sock(sk);
988 	}
989 	ulen += sizeof(struct udphdr);
990 
991 	memset(&fl, 0, sizeof(fl));
992 
993 	if (sin6) {
994 		if (sin6->sin6_port == 0)
995 			return -EINVAL;
996 
997 		fl.fl_ip_dport = sin6->sin6_port;
998 		daddr = &sin6->sin6_addr;
999 
1000 		if (np->sndflow) {
1001 			fl.fl6_flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1002 			if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
1003 				flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
1004 				if (flowlabel == NULL)
1005 					return -EINVAL;
1006 				daddr = &flowlabel->dst;
1007 			}
1008 		}
1009 
1010 		/*
1011 		 * Otherwise it will be difficult to maintain
1012 		 * sk->sk_dst_cache.
1013 		 */
1014 		if (sk->sk_state == TCP_ESTABLISHED &&
1015 		    ipv6_addr_equal(daddr, &np->daddr))
1016 			daddr = &np->daddr;
1017 
1018 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1019 		    sin6->sin6_scope_id &&
1020 		    ipv6_addr_type(daddr)&IPV6_ADDR_LINKLOCAL)
1021 			fl.oif = sin6->sin6_scope_id;
1022 	} else {
1023 		if (sk->sk_state != TCP_ESTABLISHED)
1024 			return -EDESTADDRREQ;
1025 
1026 		fl.fl_ip_dport = inet->inet_dport;
1027 		daddr = &np->daddr;
1028 		fl.fl6_flowlabel = np->flow_label;
1029 		connected = 1;
1030 	}
1031 
1032 	if (!fl.oif)
1033 		fl.oif = sk->sk_bound_dev_if;
1034 
1035 	if (!fl.oif)
1036 		fl.oif = np->sticky_pktinfo.ipi6_ifindex;
1037 
1038 	fl.mark = sk->sk_mark;
1039 
1040 	if (msg->msg_controllen) {
1041 		opt = &opt_space;
1042 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1043 		opt->tot_len = sizeof(*opt);
1044 
1045 		err = datagram_send_ctl(sock_net(sk), msg, &fl, opt, &hlimit, &tclass);
1046 		if (err < 0) {
1047 			fl6_sock_release(flowlabel);
1048 			return err;
1049 		}
1050 		if ((fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1051 			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
1052 			if (flowlabel == NULL)
1053 				return -EINVAL;
1054 		}
1055 		if (!(opt->opt_nflen|opt->opt_flen))
1056 			opt = NULL;
1057 		connected = 0;
1058 	}
1059 	if (opt == NULL)
1060 		opt = np->opt;
1061 	if (flowlabel)
1062 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1063 	opt = ipv6_fixup_options(&opt_space, opt);
1064 
1065 	fl.proto = sk->sk_protocol;
1066 	if (!ipv6_addr_any(daddr))
1067 		ipv6_addr_copy(&fl.fl6_dst, daddr);
1068 	else
1069 		fl.fl6_dst.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1070 	if (ipv6_addr_any(&fl.fl6_src) && !ipv6_addr_any(&np->saddr))
1071 		ipv6_addr_copy(&fl.fl6_src, &np->saddr);
1072 	fl.fl_ip_sport = inet->inet_sport;
1073 
1074 	/* merge ip6_build_xmit from ip6_output */
1075 	if (opt && opt->srcrt) {
1076 		struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
1077 		ipv6_addr_copy(&final, &fl.fl6_dst);
1078 		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
1079 		final_p = &final;
1080 		connected = 0;
1081 	}
1082 
1083 	if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst)) {
1084 		fl.oif = np->mcast_oif;
1085 		connected = 0;
1086 	}
1087 
1088 	security_sk_classify_flow(sk, &fl);
1089 
1090 	err = ip6_sk_dst_lookup(sk, &dst, &fl);
1091 	if (err)
1092 		goto out;
1093 	if (final_p)
1094 		ipv6_addr_copy(&fl.fl6_dst, final_p);
1095 
1096 	err = __xfrm_lookup(sock_net(sk), &dst, &fl, sk, XFRM_LOOKUP_WAIT);
1097 	if (err < 0) {
1098 		if (err == -EREMOTE)
1099 			err = ip6_dst_blackhole(sk, &dst, &fl);
1100 		if (err < 0)
1101 			goto out;
1102 	}
1103 
1104 	if (hlimit < 0) {
1105 		if (ipv6_addr_is_multicast(&fl.fl6_dst))
1106 			hlimit = np->mcast_hops;
1107 		else
1108 			hlimit = np->hop_limit;
1109 		if (hlimit < 0)
1110 			hlimit = ip6_dst_hoplimit(dst);
1111 	}
1112 
1113 	if (tclass < 0)
1114 		tclass = np->tclass;
1115 
1116 	if (msg->msg_flags&MSG_CONFIRM)
1117 		goto do_confirm;
1118 back_from_confirm:
1119 
1120 	lock_sock(sk);
1121 	if (unlikely(up->pending)) {
1122 		/* The socket is already corked while preparing it. */
1123 		/* ... which is an evident application bug. --ANK */
1124 		release_sock(sk);
1125 
1126 		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
1127 		err = -EINVAL;
1128 		goto out;
1129 	}
1130 
1131 	up->pending = AF_INET6;
1132 
1133 do_append_data:
1134 	up->len += ulen;
1135 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1136 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
1137 		sizeof(struct udphdr), hlimit, tclass, opt, &fl,
1138 		(struct rt6_info*)dst,
1139 		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1140 	if (err)
1141 		udp_v6_flush_pending_frames(sk);
1142 	else if (!corkreq)
1143 		err = udp_v6_push_pending_frames(sk);
1144 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1145 		up->pending = 0;
1146 
1147 	if (dst) {
1148 		if (connected) {
1149 			ip6_dst_store(sk, dst,
1150 				      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
1151 				      &np->daddr : NULL,
1152 #ifdef CONFIG_IPV6_SUBTREES
1153 				      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
1154 				      &np->saddr :
1155 #endif
1156 				      NULL);
1157 		} else {
1158 			dst_release(dst);
1159 		}
1160 		dst = NULL;
1161 	}
1162 
1163 	if (err > 0)
1164 		err = np->recverr ? net_xmit_errno(err) : 0;
1165 	release_sock(sk);
1166 out:
1167 	dst_release(dst);
1168 	fl6_sock_release(flowlabel);
1169 	if (!err)
1170 		return len;
1171 	/*
1172 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1173 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1174 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1175 	 * things).  We could add another new stat but at least for now that
1176 	 * seems like overkill.
1177 	 */
1178 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1179 		UDP6_INC_STATS_USER(sock_net(sk),
1180 				UDP_MIB_SNDBUFERRORS, is_udplite);
1181 	}
1182 	return err;
1183 
1184 do_confirm:
1185 	dst_confirm(dst);
1186 	if (!(msg->msg_flags&MSG_PROBE) || len)
1187 		goto back_from_confirm;
1188 	err = 0;
1189 	goto out;
1190 }
1191 
1192 void udpv6_destroy_sock(struct sock *sk)
1193 {
1194 	lock_sock(sk);
1195 	udp_v6_flush_pending_frames(sk);
1196 	release_sock(sk);
1197 
1198 	inet6_destroy_sock(sk);
1199 }
1200 
1201 /*
1202  *	Socket option code for UDP
1203  */
1204 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1205 		     char __user *optval, unsigned int optlen)
1206 {
1207 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1208 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1209 					  udp_v6_push_pending_frames);
1210 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1211 }
1212 
1213 #ifdef CONFIG_COMPAT
1214 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1215 			    char __user *optval, unsigned int optlen)
1216 {
1217 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1218 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1219 					  udp_v6_push_pending_frames);
1220 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1221 }
1222 #endif
1223 
1224 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1225 		     char __user *optval, int __user *optlen)
1226 {
1227 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1228 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1229 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1230 }
1231 
1232 #ifdef CONFIG_COMPAT
1233 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1234 			    char __user *optval, int __user *optlen)
1235 {
1236 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1237 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1238 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1239 }
1240 #endif
1241 
1242 static int udp6_ufo_send_check(struct sk_buff *skb)
1243 {
1244 	struct ipv6hdr *ipv6h;
1245 	struct udphdr *uh;
1246 
1247 	if (!pskb_may_pull(skb, sizeof(*uh)))
1248 		return -EINVAL;
1249 
1250 	ipv6h = ipv6_hdr(skb);
1251 	uh = udp_hdr(skb);
1252 
1253 	uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
1254 				     IPPROTO_UDP, 0);
1255 	skb->csum_start = skb_transport_header(skb) - skb->head;
1256 	skb->csum_offset = offsetof(struct udphdr, check);
1257 	skb->ip_summed = CHECKSUM_PARTIAL;
1258 	return 0;
1259 }
1260 
1261 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, int features)
1262 {
1263 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1264 	unsigned int mss;
1265 	unsigned int unfrag_ip6hlen, unfrag_len;
1266 	struct frag_hdr *fptr;
1267 	u8 *mac_start, *prevhdr;
1268 	u8 nexthdr;
1269 	u8 frag_hdr_sz = sizeof(struct frag_hdr);
1270 	int offset;
1271 	__wsum csum;
1272 
1273 	mss = skb_shinfo(skb)->gso_size;
1274 	if (unlikely(skb->len <= mss))
1275 		goto out;
1276 
1277 	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
1278 		/* Packet is from an untrusted source, reset gso_segs. */
1279 		int type = skb_shinfo(skb)->gso_type;
1280 
1281 		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
1282 			     !(type & (SKB_GSO_UDP))))
1283 			goto out;
1284 
1285 		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
1286 
1287 		segs = NULL;
1288 		goto out;
1289 	}
1290 
1291 	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
1292 	 * do checksum of UDP packets sent as multiple IP fragments.
1293 	 */
1294 	offset = skb->csum_start - skb_headroom(skb);
1295 	csum = skb_checksum(skb, offset, skb->len- offset, 0);
1296 	offset += skb->csum_offset;
1297 	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
1298 	skb->ip_summed = CHECKSUM_NONE;
1299 
1300 	/* Check if there is enough headroom to insert fragment header. */
1301 	if ((skb_headroom(skb) < frag_hdr_sz) &&
1302 	    pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
1303 		goto out;
1304 
1305 	/* Find the unfragmentable header and shift it left by frag_hdr_sz
1306 	 * bytes to insert fragment header.
1307 	 */
1308 	unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
1309 	nexthdr = *prevhdr;
1310 	*prevhdr = NEXTHDR_FRAGMENT;
1311 	unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
1312 		     unfrag_ip6hlen;
1313 	mac_start = skb_mac_header(skb);
1314 	memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
1315 
1316 	skb->mac_header -= frag_hdr_sz;
1317 	skb->network_header -= frag_hdr_sz;
1318 
1319 	fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
1320 	fptr->nexthdr = nexthdr;
1321 	fptr->reserved = 0;
1322 	ipv6_select_ident(fptr);
1323 
1324 	/* Fragment the skb. ipv6 header and the remaining fields of the
1325 	 * fragment header are updated in ipv6_gso_segment()
1326 	 */
1327 	segs = skb_segment(skb, features);
1328 
1329 out:
1330 	return segs;
1331 }
1332 
1333 static const struct inet6_protocol udpv6_protocol = {
1334 	.handler	=	udpv6_rcv,
1335 	.err_handler	=	udpv6_err,
1336 	.gso_send_check =	udp6_ufo_send_check,
1337 	.gso_segment	=	udp6_ufo_fragment,
1338 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1339 };
1340 
1341 /* ------------------------------------------------------------------------ */
1342 #ifdef CONFIG_PROC_FS
1343 
1344 static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket)
1345 {
1346 	struct inet_sock *inet = inet_sk(sp);
1347 	struct ipv6_pinfo *np = inet6_sk(sp);
1348 	struct in6_addr *dest, *src;
1349 	__u16 destp, srcp;
1350 
1351 	dest  = &np->daddr;
1352 	src   = &np->rcv_saddr;
1353 	destp = ntohs(inet->inet_dport);
1354 	srcp  = ntohs(inet->inet_sport);
1355 	seq_printf(seq,
1356 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1357 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d\n",
1358 		   bucket,
1359 		   src->s6_addr32[0], src->s6_addr32[1],
1360 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1361 		   dest->s6_addr32[0], dest->s6_addr32[1],
1362 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1363 		   sp->sk_state,
1364 		   sk_wmem_alloc_get(sp),
1365 		   sk_rmem_alloc_get(sp),
1366 		   0, 0L, 0,
1367 		   sock_i_uid(sp), 0,
1368 		   sock_i_ino(sp),
1369 		   atomic_read(&sp->sk_refcnt), sp,
1370 		   atomic_read(&sp->sk_drops));
1371 }
1372 
1373 int udp6_seq_show(struct seq_file *seq, void *v)
1374 {
1375 	if (v == SEQ_START_TOKEN)
1376 		seq_printf(seq,
1377 			   "  sl  "
1378 			   "local_address                         "
1379 			   "remote_address                        "
1380 			   "st tx_queue rx_queue tr tm->when retrnsmt"
1381 			   "   uid  timeout inode ref pointer drops\n");
1382 	else
1383 		udp6_sock_seq_show(seq, v, ((struct udp_iter_state *)seq->private)->bucket);
1384 	return 0;
1385 }
1386 
1387 static struct udp_seq_afinfo udp6_seq_afinfo = {
1388 	.name		= "udp6",
1389 	.family		= AF_INET6,
1390 	.udp_table	= &udp_table,
1391 	.seq_fops	= {
1392 		.owner	=	THIS_MODULE,
1393 	},
1394 	.seq_ops	= {
1395 		.show		= udp6_seq_show,
1396 	},
1397 };
1398 
1399 int udp6_proc_init(struct net *net)
1400 {
1401 	return udp_proc_register(net, &udp6_seq_afinfo);
1402 }
1403 
1404 void udp6_proc_exit(struct net *net) {
1405 	udp_proc_unregister(net, &udp6_seq_afinfo);
1406 }
1407 #endif /* CONFIG_PROC_FS */
1408 
1409 /* ------------------------------------------------------------------------ */
1410 
1411 struct proto udpv6_prot = {
1412 	.name		   = "UDPv6",
1413 	.owner		   = THIS_MODULE,
1414 	.close		   = udp_lib_close,
1415 	.connect	   = ip6_datagram_connect,
1416 	.disconnect	   = udp_disconnect,
1417 	.ioctl		   = udp_ioctl,
1418 	.destroy	   = udpv6_destroy_sock,
1419 	.setsockopt	   = udpv6_setsockopt,
1420 	.getsockopt	   = udpv6_getsockopt,
1421 	.sendmsg	   = udpv6_sendmsg,
1422 	.recvmsg	   = udpv6_recvmsg,
1423 	.backlog_rcv	   = udpv6_queue_rcv_skb,
1424 	.hash		   = udp_lib_hash,
1425 	.unhash		   = udp_lib_unhash,
1426 	.get_port	   = udp_v6_get_port,
1427 	.memory_allocated  = &udp_memory_allocated,
1428 	.sysctl_mem	   = sysctl_udp_mem,
1429 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1430 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1431 	.obj_size	   = sizeof(struct udp6_sock),
1432 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1433 	.h.udp_table	   = &udp_table,
1434 #ifdef CONFIG_COMPAT
1435 	.compat_setsockopt = compat_udpv6_setsockopt,
1436 	.compat_getsockopt = compat_udpv6_getsockopt,
1437 #endif
1438 };
1439 
1440 static struct inet_protosw udpv6_protosw = {
1441 	.type =      SOCK_DGRAM,
1442 	.protocol =  IPPROTO_UDP,
1443 	.prot =      &udpv6_prot,
1444 	.ops =       &inet6_dgram_ops,
1445 	.no_check =  UDP_CSUM_DEFAULT,
1446 	.flags =     INET_PROTOSW_PERMANENT,
1447 };
1448 
1449 
1450 int __init udpv6_init(void)
1451 {
1452 	int ret;
1453 
1454 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1455 	if (ret)
1456 		goto out;
1457 
1458 	ret = inet6_register_protosw(&udpv6_protosw);
1459 	if (ret)
1460 		goto out_udpv6_protocol;
1461 out:
1462 	return ret;
1463 
1464 out_udpv6_protocol:
1465 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1466 	goto out;
1467 }
1468 
1469 void udpv6_exit(void)
1470 {
1471 	inet6_unregister_protosw(&udpv6_protosw);
1472 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1473 }
1474