xref: /linux/net/ipv6/udp.c (revision 44b111b519160e33fdc41eadb39af86a24707edf)
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 
49 #include <linux/proc_fs.h>
50 #include <linux/seq_file.h>
51 #include "udp_impl.h"
52 
53 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
54 {
55 	const struct in6_addr *sk_rcv_saddr6 = &inet6_sk(sk)->rcv_saddr;
56 	const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2);
57 	__be32 sk1_rcv_saddr = sk_rcv_saddr(sk);
58 	__be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);
59 	int sk_ipv6only = ipv6_only_sock(sk);
60 	int sk2_ipv6only = inet_v6_ipv6only(sk2);
61 	int addr_type = ipv6_addr_type(sk_rcv_saddr6);
62 	int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED;
63 
64 	/* if both are mapped, treat as IPv4 */
65 	if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED)
66 		return (!sk2_ipv6only &&
67 			(!sk1_rcv_saddr || !sk2_rcv_saddr ||
68 			  sk1_rcv_saddr == sk2_rcv_saddr));
69 
70 	if (addr_type2 == IPV6_ADDR_ANY &&
71 	    !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED))
72 		return 1;
73 
74 	if (addr_type == IPV6_ADDR_ANY &&
75 	    !(sk_ipv6only && addr_type2 == IPV6_ADDR_MAPPED))
76 		return 1;
77 
78 	if (sk2_rcv_saddr6 &&
79 	    ipv6_addr_equal(sk_rcv_saddr6, sk2_rcv_saddr6))
80 		return 1;
81 
82 	return 0;
83 }
84 
85 static unsigned int udp6_portaddr_hash(struct net *net,
86 				       const struct in6_addr *addr6,
87 				       unsigned int port)
88 {
89 	unsigned int hash, mix = net_hash_mix(net);
90 
91 	if (ipv6_addr_any(addr6))
92 		hash = jhash_1word(0, mix);
93 	else if (ipv6_addr_v4mapped(addr6))
94 		hash = jhash_1word((__force u32)addr6->s6_addr32[3], mix);
95 	else
96 		hash = jhash2((__force u32 *)addr6->s6_addr32, 4, mix);
97 
98 	return hash ^ port;
99 }
100 
101 
102 int udp_v6_get_port(struct sock *sk, unsigned short snum)
103 {
104 	unsigned int hash2_nulladdr =
105 		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
106 	unsigned int hash2_partial =
107 		udp6_portaddr_hash(sock_net(sk), &inet6_sk(sk)->rcv_saddr, 0);
108 
109 	/* precompute partial secondary hash */
110 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
111 	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
112 }
113 
114 static void udp_v6_rehash(struct sock *sk)
115 {
116 	u16 new_hash = udp6_portaddr_hash(sock_net(sk),
117 					  &inet6_sk(sk)->rcv_saddr,
118 					  inet_sk(sk)->inet_num);
119 
120 	udp_lib_rehash(sk, new_hash);
121 }
122 
123 static inline int compute_score(struct sock *sk, struct net *net,
124 				unsigned short hnum,
125 				const struct in6_addr *saddr, __be16 sport,
126 				const struct in6_addr *daddr, __be16 dport,
127 				int dif)
128 {
129 	int score = -1;
130 
131 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
132 			sk->sk_family == PF_INET6) {
133 		struct ipv6_pinfo *np = inet6_sk(sk);
134 		struct inet_sock *inet = inet_sk(sk);
135 
136 		score = 0;
137 		if (inet->inet_dport) {
138 			if (inet->inet_dport != sport)
139 				return -1;
140 			score++;
141 		}
142 		if (!ipv6_addr_any(&np->rcv_saddr)) {
143 			if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
144 				return -1;
145 			score++;
146 		}
147 		if (!ipv6_addr_any(&np->daddr)) {
148 			if (!ipv6_addr_equal(&np->daddr, saddr))
149 				return -1;
150 			score++;
151 		}
152 		if (sk->sk_bound_dev_if) {
153 			if (sk->sk_bound_dev_if != dif)
154 				return -1;
155 			score++;
156 		}
157 	}
158 	return score;
159 }
160 
161 #define SCORE2_MAX (1 + 1 + 1)
162 static inline int compute_score2(struct sock *sk, struct net *net,
163 				const struct in6_addr *saddr, __be16 sport,
164 				const struct in6_addr *daddr, unsigned short hnum,
165 				int dif)
166 {
167 	int score = -1;
168 
169 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
170 			sk->sk_family == PF_INET6) {
171 		struct ipv6_pinfo *np = inet6_sk(sk);
172 		struct inet_sock *inet = inet_sk(sk);
173 
174 		if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
175 			return -1;
176 		score = 0;
177 		if (inet->inet_dport) {
178 			if (inet->inet_dport != sport)
179 				return -1;
180 			score++;
181 		}
182 		if (!ipv6_addr_any(&np->daddr)) {
183 			if (!ipv6_addr_equal(&np->daddr, saddr))
184 				return -1;
185 			score++;
186 		}
187 		if (sk->sk_bound_dev_if) {
188 			if (sk->sk_bound_dev_if != dif)
189 				return -1;
190 			score++;
191 		}
192 	}
193 	return score;
194 }
195 
196 
197 /* called with read_rcu_lock() */
198 static struct sock *udp6_lib_lookup2(struct net *net,
199 		const struct in6_addr *saddr, __be16 sport,
200 		const struct in6_addr *daddr, unsigned int hnum, int dif,
201 		struct udp_hslot *hslot2, unsigned int slot2)
202 {
203 	struct sock *sk, *result;
204 	struct hlist_nulls_node *node;
205 	int score, badness;
206 
207 begin:
208 	result = NULL;
209 	badness = -1;
210 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
211 		score = compute_score2(sk, net, saddr, sport,
212 				      daddr, hnum, dif);
213 		if (score > badness) {
214 			result = sk;
215 			badness = score;
216 			if (score == SCORE2_MAX)
217 				goto exact_match;
218 		}
219 	}
220 	/*
221 	 * if the nulls value we got at the end of this lookup is
222 	 * not the expected one, we must restart lookup.
223 	 * We probably met an item that was moved to another chain.
224 	 */
225 	if (get_nulls_value(node) != slot2)
226 		goto begin;
227 
228 	if (result) {
229 exact_match:
230 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
231 			result = NULL;
232 		else if (unlikely(compute_score2(result, net, saddr, sport,
233 				  daddr, hnum, dif) < badness)) {
234 			sock_put(result);
235 			goto begin;
236 		}
237 	}
238 	return result;
239 }
240 
241 static struct sock *__udp6_lib_lookup(struct net *net,
242 				      const struct in6_addr *saddr, __be16 sport,
243 				      const struct in6_addr *daddr, __be16 dport,
244 				      int dif, struct udp_table *udptable)
245 {
246 	struct sock *sk, *result;
247 	struct hlist_nulls_node *node;
248 	unsigned short hnum = ntohs(dport);
249 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
250 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
251 	int score, badness;
252 
253 	rcu_read_lock();
254 	if (hslot->count > 10) {
255 		hash2 = udp6_portaddr_hash(net, daddr, 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, saddr, sport,
262 					  daddr, hnum, dif,
263 					  hslot2, slot2);
264 		if (!result) {
265 			hash2 = udp6_portaddr_hash(net, &in6addr_any, hnum);
266 			slot2 = hash2 & udptable->mask;
267 			hslot2 = &udptable->hash2[slot2];
268 			if (hslot->count < hslot2->count)
269 				goto begin;
270 
271 			result = udp6_lib_lookup2(net, saddr, sport,
272 						  &in6addr_any, hnum, dif,
273 						  hslot2, slot2);
274 		}
275 		rcu_read_unlock();
276 		return result;
277 	}
278 begin:
279 	result = NULL;
280 	badness = -1;
281 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
282 		score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
283 		if (score > badness) {
284 			result = sk;
285 			badness = score;
286 		}
287 	}
288 	/*
289 	 * if the nulls value we got at the end of this lookup is
290 	 * not the expected one, we must restart lookup.
291 	 * We probably met an item that was moved to another chain.
292 	 */
293 	if (get_nulls_value(node) != slot)
294 		goto begin;
295 
296 	if (result) {
297 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
298 			result = NULL;
299 		else if (unlikely(compute_score(result, net, hnum, saddr, sport,
300 					daddr, dport, dif) < badness)) {
301 			sock_put(result);
302 			goto begin;
303 		}
304 	}
305 	rcu_read_unlock();
306 	return result;
307 }
308 
309 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
310 					  __be16 sport, __be16 dport,
311 					  struct udp_table *udptable)
312 {
313 	struct sock *sk;
314 	const struct ipv6hdr *iph = ipv6_hdr(skb);
315 
316 	if (unlikely(sk = skb_steal_sock(skb)))
317 		return sk;
318 	return __udp6_lib_lookup(dev_net(skb_dst(skb)->dev), &iph->saddr, sport,
319 				 &iph->daddr, dport, inet6_iif(skb),
320 				 udptable);
321 }
322 
323 struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
324 			     const struct in6_addr *daddr, __be16 dport, int dif)
325 {
326 	return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
327 }
328 EXPORT_SYMBOL_GPL(udp6_lib_lookup);
329 
330 
331 /*
332  * 	This should be easy, if there is something there we
333  * 	return it, otherwise we block.
334  */
335 
336 int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
337 		  struct msghdr *msg, size_t len,
338 		  int noblock, int flags, int *addr_len)
339 {
340 	struct ipv6_pinfo *np = inet6_sk(sk);
341 	struct inet_sock *inet = inet_sk(sk);
342 	struct sk_buff *skb;
343 	unsigned int ulen, copied;
344 	int peeked;
345 	int err;
346 	int is_udplite = IS_UDPLITE(sk);
347 	int is_udp4;
348 	bool slow;
349 
350 	if (addr_len)
351 		*addr_len=sizeof(struct sockaddr_in6);
352 
353 	if (flags & MSG_ERRQUEUE)
354 		return ipv6_recv_error(sk, msg, len);
355 
356 	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
357 		return ipv6_recv_rxpmtu(sk, msg, len);
358 
359 try_again:
360 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
361 				  &peeked, &err);
362 	if (!skb)
363 		goto out;
364 
365 	ulen = skb->len - sizeof(struct udphdr);
366 	copied = len;
367 	if (copied > ulen)
368 		copied = ulen;
369 	else if (copied < ulen)
370 		msg->msg_flags |= MSG_TRUNC;
371 
372 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
373 
374 	/*
375 	 * If checksum is needed at all, try to do it while copying the
376 	 * data.  If the data is truncated, or if we only want a partial
377 	 * coverage checksum (UDP-Lite), do it before the copy.
378 	 */
379 
380 	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
381 		if (udp_lib_checksum_complete(skb))
382 			goto csum_copy_err;
383 	}
384 
385 	if (skb_csum_unnecessary(skb))
386 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
387 					      msg->msg_iov, copied       );
388 	else {
389 		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
390 		if (err == -EINVAL)
391 			goto csum_copy_err;
392 	}
393 	if (err)
394 		goto out_free;
395 
396 	if (!peeked) {
397 		if (is_udp4)
398 			UDP_INC_STATS_USER(sock_net(sk),
399 					UDP_MIB_INDATAGRAMS, is_udplite);
400 		else
401 			UDP6_INC_STATS_USER(sock_net(sk),
402 					UDP_MIB_INDATAGRAMS, is_udplite);
403 	}
404 
405 	sock_recv_ts_and_drops(msg, sk, skb);
406 
407 	/* Copy the address. */
408 	if (msg->msg_name) {
409 		struct sockaddr_in6 *sin6;
410 
411 		sin6 = (struct sockaddr_in6 *) msg->msg_name;
412 		sin6->sin6_family = AF_INET6;
413 		sin6->sin6_port = udp_hdr(skb)->source;
414 		sin6->sin6_flowinfo = 0;
415 		sin6->sin6_scope_id = 0;
416 
417 		if (is_udp4)
418 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
419 					       &sin6->sin6_addr);
420 		else {
421 			ipv6_addr_copy(&sin6->sin6_addr,
422 				       &ipv6_hdr(skb)->saddr);
423 			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
424 				sin6->sin6_scope_id = IP6CB(skb)->iif;
425 		}
426 
427 	}
428 	if (is_udp4) {
429 		if (inet->cmsg_flags)
430 			ip_cmsg_recv(msg, skb);
431 	} else {
432 		if (np->rxopt.all)
433 			datagram_recv_ctl(sk, msg, skb);
434 	}
435 
436 	err = copied;
437 	if (flags & MSG_TRUNC)
438 		err = ulen;
439 
440 out_free:
441 	skb_free_datagram_locked(sk, skb);
442 out:
443 	return err;
444 
445 csum_copy_err:
446 	slow = lock_sock_fast(sk);
447 	if (!skb_kill_datagram(sk, skb, flags)) {
448 		if (is_udp4)
449 			UDP_INC_STATS_USER(sock_net(sk),
450 					UDP_MIB_INERRORS, is_udplite);
451 		else
452 			UDP6_INC_STATS_USER(sock_net(sk),
453 					UDP_MIB_INERRORS, is_udplite);
454 	}
455 	unlock_sock_fast(sk, slow);
456 
457 	if (noblock)
458 		return -EAGAIN;
459 
460 	/* starting over for a new packet */
461 	msg->msg_flags &= ~MSG_TRUNC;
462 	goto try_again;
463 }
464 
465 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
466 		    u8 type, u8 code, int offset, __be32 info,
467 		    struct udp_table *udptable)
468 {
469 	struct ipv6_pinfo *np;
470 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
471 	const struct in6_addr *saddr = &hdr->saddr;
472 	const struct in6_addr *daddr = &hdr->daddr;
473 	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
474 	struct sock *sk;
475 	int err;
476 
477 	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
478 			       saddr, uh->source, inet6_iif(skb), udptable);
479 	if (sk == NULL)
480 		return;
481 
482 	np = inet6_sk(sk);
483 
484 	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
485 		goto out;
486 
487 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
488 		goto out;
489 
490 	if (np->recverr)
491 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
492 
493 	sk->sk_err = err;
494 	sk->sk_error_report(sk);
495 out:
496 	sock_put(sk);
497 }
498 
499 static __inline__ void udpv6_err(struct sk_buff *skb,
500 				 struct inet6_skb_parm *opt, u8 type,
501 				 u8 code, int offset, __be32 info     )
502 {
503 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
504 }
505 
506 int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
507 {
508 	struct udp_sock *up = udp_sk(sk);
509 	int rc;
510 	int is_udplite = IS_UDPLITE(sk);
511 
512 	if (!ipv6_addr_any(&inet6_sk(sk)->daddr))
513 		sock_rps_save_rxhash(sk, skb);
514 
515 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
516 		goto drop;
517 
518 	/*
519 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
520 	 */
521 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
522 
523 		if (up->pcrlen == 0) {          /* full coverage was set  */
524 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
525 				" %d while full coverage %d requested\n",
526 				UDP_SKB_CB(skb)->cscov, skb->len);
527 			goto drop;
528 		}
529 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
530 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
531 						    "too small, need min %d\n",
532 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
533 			goto drop;
534 		}
535 	}
536 
537 	if (rcu_access_pointer(sk->sk_filter)) {
538 		if (udp_lib_checksum_complete(skb))
539 			goto drop;
540 	}
541 
542 	if ((rc = ip_queue_rcv_skb(sk, skb)) < 0) {
543 		/* Note that an ENOMEM error is charged twice */
544 		if (rc == -ENOMEM)
545 			UDP6_INC_STATS_BH(sock_net(sk),
546 					UDP_MIB_RCVBUFERRORS, is_udplite);
547 		goto drop_no_sk_drops_inc;
548 	}
549 
550 	return 0;
551 drop:
552 	atomic_inc(&sk->sk_drops);
553 drop_no_sk_drops_inc:
554 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
555 	kfree_skb(skb);
556 	return -1;
557 }
558 
559 static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
560 				      __be16 loc_port, const struct in6_addr *loc_addr,
561 				      __be16 rmt_port, const struct in6_addr *rmt_addr,
562 				      int dif)
563 {
564 	struct hlist_nulls_node *node;
565 	struct sock *s = sk;
566 	unsigned short num = ntohs(loc_port);
567 
568 	sk_nulls_for_each_from(s, node) {
569 		struct inet_sock *inet = inet_sk(s);
570 
571 		if (!net_eq(sock_net(s), net))
572 			continue;
573 
574 		if (udp_sk(s)->udp_port_hash == num &&
575 		    s->sk_family == PF_INET6) {
576 			struct ipv6_pinfo *np = inet6_sk(s);
577 			if (inet->inet_dport) {
578 				if (inet->inet_dport != rmt_port)
579 					continue;
580 			}
581 			if (!ipv6_addr_any(&np->daddr) &&
582 			    !ipv6_addr_equal(&np->daddr, rmt_addr))
583 				continue;
584 
585 			if (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)
586 				continue;
587 
588 			if (!ipv6_addr_any(&np->rcv_saddr)) {
589 				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
590 					continue;
591 			}
592 			if (!inet6_mc_check(s, loc_addr, rmt_addr))
593 				continue;
594 			return s;
595 		}
596 	}
597 	return NULL;
598 }
599 
600 static void flush_stack(struct sock **stack, unsigned int count,
601 			struct sk_buff *skb, unsigned int final)
602 {
603 	unsigned int i;
604 	struct sock *sk;
605 	struct sk_buff *skb1;
606 
607 	for (i = 0; i < count; i++) {
608 		skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
609 
610 		sk = stack[i];
611 		if (skb1) {
612 			if (sk_rcvqueues_full(sk, skb1)) {
613 				kfree_skb(skb1);
614 				goto drop;
615 			}
616 			bh_lock_sock(sk);
617 			if (!sock_owned_by_user(sk))
618 				udpv6_queue_rcv_skb(sk, skb1);
619 			else if (sk_add_backlog(sk, skb1)) {
620 				kfree_skb(skb1);
621 				bh_unlock_sock(sk);
622 				goto drop;
623 			}
624 			bh_unlock_sock(sk);
625 			continue;
626 		}
627 drop:
628 		atomic_inc(&sk->sk_drops);
629 		UDP6_INC_STATS_BH(sock_net(sk),
630 				UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
631 		UDP6_INC_STATS_BH(sock_net(sk),
632 				UDP_MIB_INERRORS, IS_UDPLITE(sk));
633 	}
634 }
635 /*
636  * Note: called only from the BH handler context,
637  * so we don't need to lock the hashes.
638  */
639 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
640 		const struct in6_addr *saddr, const struct in6_addr *daddr,
641 		struct udp_table *udptable)
642 {
643 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
644 	const struct udphdr *uh = udp_hdr(skb);
645 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
646 	int dif;
647 	unsigned int i, count = 0;
648 
649 	spin_lock(&hslot->lock);
650 	sk = sk_nulls_head(&hslot->head);
651 	dif = inet6_iif(skb);
652 	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
653 	while (sk) {
654 		stack[count++] = sk;
655 		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
656 				       uh->source, saddr, dif);
657 		if (unlikely(count == ARRAY_SIZE(stack))) {
658 			if (!sk)
659 				break;
660 			flush_stack(stack, count, skb, ~0);
661 			count = 0;
662 		}
663 	}
664 	/*
665 	 * before releasing the lock, we must take reference on sockets
666 	 */
667 	for (i = 0; i < count; i++)
668 		sock_hold(stack[i]);
669 
670 	spin_unlock(&hslot->lock);
671 
672 	if (count) {
673 		flush_stack(stack, count, skb, count - 1);
674 
675 		for (i = 0; i < count; i++)
676 			sock_put(stack[i]);
677 	} else {
678 		kfree_skb(skb);
679 	}
680 	return 0;
681 }
682 
683 static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
684 				 int proto)
685 {
686 	int err;
687 
688 	UDP_SKB_CB(skb)->partial_cov = 0;
689 	UDP_SKB_CB(skb)->cscov = skb->len;
690 
691 	if (proto == IPPROTO_UDPLITE) {
692 		err = udplite_checksum_init(skb, uh);
693 		if (err)
694 			return err;
695 	}
696 
697 	if (uh->check == 0) {
698 		/* RFC 2460 section 8.1 says that we SHOULD log
699 		   this error. Well, it is reasonable.
700 		 */
701 		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0\n");
702 		return 1;
703 	}
704 	if (skb->ip_summed == CHECKSUM_COMPLETE &&
705 	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
706 			     skb->len, proto, skb->csum))
707 		skb->ip_summed = CHECKSUM_UNNECESSARY;
708 
709 	if (!skb_csum_unnecessary(skb))
710 		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
711 							 &ipv6_hdr(skb)->daddr,
712 							 skb->len, proto, 0));
713 
714 	return 0;
715 }
716 
717 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
718 		   int proto)
719 {
720 	struct net *net = dev_net(skb->dev);
721 	struct sock *sk;
722 	struct udphdr *uh;
723 	const struct in6_addr *saddr, *daddr;
724 	u32 ulen = 0;
725 
726 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
727 		goto discard;
728 
729 	saddr = &ipv6_hdr(skb)->saddr;
730 	daddr = &ipv6_hdr(skb)->daddr;
731 	uh = udp_hdr(skb);
732 
733 	ulen = ntohs(uh->len);
734 	if (ulen > skb->len)
735 		goto short_packet;
736 
737 	if (proto == IPPROTO_UDP) {
738 		/* UDP validates ulen. */
739 
740 		/* Check for jumbo payload */
741 		if (ulen == 0)
742 			ulen = skb->len;
743 
744 		if (ulen < sizeof(*uh))
745 			goto short_packet;
746 
747 		if (ulen < skb->len) {
748 			if (pskb_trim_rcsum(skb, ulen))
749 				goto short_packet;
750 			saddr = &ipv6_hdr(skb)->saddr;
751 			daddr = &ipv6_hdr(skb)->daddr;
752 			uh = udp_hdr(skb);
753 		}
754 	}
755 
756 	if (udp6_csum_init(skb, uh, proto))
757 		goto discard;
758 
759 	/*
760 	 *	Multicast receive code
761 	 */
762 	if (ipv6_addr_is_multicast(daddr))
763 		return __udp6_lib_mcast_deliver(net, skb,
764 				saddr, daddr, udptable);
765 
766 	/* Unicast */
767 
768 	/*
769 	 * check socket cache ... must talk to Alan about his plans
770 	 * for sock caches... i'll skip this for now.
771 	 */
772 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
773 
774 	if (sk == NULL) {
775 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
776 			goto discard;
777 
778 		if (udp_lib_checksum_complete(skb))
779 			goto discard;
780 		UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS,
781 				proto == IPPROTO_UDPLITE);
782 
783 		icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
784 
785 		kfree_skb(skb);
786 		return 0;
787 	}
788 
789 	/* deliver */
790 
791 	if (sk_rcvqueues_full(sk, skb)) {
792 		sock_put(sk);
793 		goto discard;
794 	}
795 	bh_lock_sock(sk);
796 	if (!sock_owned_by_user(sk))
797 		udpv6_queue_rcv_skb(sk, skb);
798 	else if (sk_add_backlog(sk, skb)) {
799 		atomic_inc(&sk->sk_drops);
800 		bh_unlock_sock(sk);
801 		sock_put(sk);
802 		goto discard;
803 	}
804 	bh_unlock_sock(sk);
805 	sock_put(sk);
806 	return 0;
807 
808 short_packet:
809 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
810 		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
811 		       saddr,
812 		       ntohs(uh->source),
813 		       ulen,
814 		       skb->len,
815 		       daddr,
816 		       ntohs(uh->dest));
817 
818 discard:
819 	UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
820 	kfree_skb(skb);
821 	return 0;
822 }
823 
824 static __inline__ int udpv6_rcv(struct sk_buff *skb)
825 {
826 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
827 }
828 
829 /*
830  * Throw away all pending data and cancel the corking. Socket is locked.
831  */
832 static void udp_v6_flush_pending_frames(struct sock *sk)
833 {
834 	struct udp_sock *up = udp_sk(sk);
835 
836 	if (up->pending == AF_INET)
837 		udp_flush_pending_frames(sk);
838 	else if (up->pending) {
839 		up->len = 0;
840 		up->pending = 0;
841 		ip6_flush_pending_frames(sk);
842 	}
843 }
844 
845 /**
846  * 	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
847  * 	@sk: 	socket we are sending on
848  * 	@skb: 	sk_buff containing the filled-in UDP header
849  * 	        (checksum field must be zeroed out)
850  */
851 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
852 				 const struct in6_addr *saddr,
853 				 const struct in6_addr *daddr, int len)
854 {
855 	unsigned int offset;
856 	struct udphdr *uh = udp_hdr(skb);
857 	__wsum csum = 0;
858 
859 	if (skb_queue_len(&sk->sk_write_queue) == 1) {
860 		/* Only one fragment on the socket.  */
861 		skb->csum_start = skb_transport_header(skb) - skb->head;
862 		skb->csum_offset = offsetof(struct udphdr, check);
863 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
864 	} else {
865 		/*
866 		 * HW-checksum won't work as there are two or more
867 		 * fragments on the socket so that all csums of sk_buffs
868 		 * should be together
869 		 */
870 		offset = skb_transport_offset(skb);
871 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
872 
873 		skb->ip_summed = CHECKSUM_NONE;
874 
875 		skb_queue_walk(&sk->sk_write_queue, skb) {
876 			csum = csum_add(csum, skb->csum);
877 		}
878 
879 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
880 					    csum);
881 		if (uh->check == 0)
882 			uh->check = CSUM_MANGLED_0;
883 	}
884 }
885 
886 /*
887  *	Sending
888  */
889 
890 static int udp_v6_push_pending_frames(struct sock *sk)
891 {
892 	struct sk_buff *skb;
893 	struct udphdr *uh;
894 	struct udp_sock  *up = udp_sk(sk);
895 	struct inet_sock *inet = inet_sk(sk);
896 	struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
897 	int err = 0;
898 	int is_udplite = IS_UDPLITE(sk);
899 	__wsum csum = 0;
900 
901 	/* Grab the skbuff where UDP header space exists. */
902 	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
903 		goto out;
904 
905 	/*
906 	 * Create a UDP header
907 	 */
908 	uh = udp_hdr(skb);
909 	uh->source = fl6->fl6_sport;
910 	uh->dest = fl6->fl6_dport;
911 	uh->len = htons(up->len);
912 	uh->check = 0;
913 
914 	if (is_udplite)
915 		csum = udplite_csum_outgoing(sk, skb);
916 	else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
917 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr,
918 				     up->len);
919 		goto send;
920 	} else
921 		csum = udp_csum_outgoing(sk, skb);
922 
923 	/* add protocol-dependent pseudo-header */
924 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
925 				    up->len, fl6->flowi6_proto, csum);
926 	if (uh->check == 0)
927 		uh->check = CSUM_MANGLED_0;
928 
929 send:
930 	err = ip6_push_pending_frames(sk);
931 	if (err) {
932 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
933 			UDP6_INC_STATS_USER(sock_net(sk),
934 					    UDP_MIB_SNDBUFERRORS, is_udplite);
935 			err = 0;
936 		}
937 	} else
938 		UDP6_INC_STATS_USER(sock_net(sk),
939 				    UDP_MIB_OUTDATAGRAMS, is_udplite);
940 out:
941 	up->len = 0;
942 	up->pending = 0;
943 	return err;
944 }
945 
946 int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
947 		  struct msghdr *msg, size_t len)
948 {
949 	struct ipv6_txoptions opt_space;
950 	struct udp_sock *up = udp_sk(sk);
951 	struct inet_sock *inet = inet_sk(sk);
952 	struct ipv6_pinfo *np = inet6_sk(sk);
953 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
954 	struct in6_addr *daddr, *final_p, final;
955 	struct ipv6_txoptions *opt = NULL;
956 	struct ip6_flowlabel *flowlabel = NULL;
957 	struct flowi6 fl6;
958 	struct dst_entry *dst;
959 	int addr_len = msg->msg_namelen;
960 	int ulen = len;
961 	int hlimit = -1;
962 	int tclass = -1;
963 	int dontfrag = -1;
964 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
965 	int err;
966 	int connected = 0;
967 	int is_udplite = IS_UDPLITE(sk);
968 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
969 
970 	/* destination address check */
971 	if (sin6) {
972 		if (addr_len < offsetof(struct sockaddr, sa_data))
973 			return -EINVAL;
974 
975 		switch (sin6->sin6_family) {
976 		case AF_INET6:
977 			if (addr_len < SIN6_LEN_RFC2133)
978 				return -EINVAL;
979 			daddr = &sin6->sin6_addr;
980 			break;
981 		case AF_INET:
982 			goto do_udp_sendmsg;
983 		case AF_UNSPEC:
984 			msg->msg_name = sin6 = NULL;
985 			msg->msg_namelen = addr_len = 0;
986 			daddr = NULL;
987 			break;
988 		default:
989 			return -EINVAL;
990 		}
991 	} else if (!up->pending) {
992 		if (sk->sk_state != TCP_ESTABLISHED)
993 			return -EDESTADDRREQ;
994 		daddr = &np->daddr;
995 	} else
996 		daddr = NULL;
997 
998 	if (daddr) {
999 		if (ipv6_addr_v4mapped(daddr)) {
1000 			struct sockaddr_in sin;
1001 			sin.sin_family = AF_INET;
1002 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1003 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
1004 			msg->msg_name = &sin;
1005 			msg->msg_namelen = sizeof(sin);
1006 do_udp_sendmsg:
1007 			if (__ipv6_only_sock(sk))
1008 				return -ENETUNREACH;
1009 			return udp_sendmsg(iocb, sk, msg, len);
1010 		}
1011 	}
1012 
1013 	if (up->pending == AF_INET)
1014 		return udp_sendmsg(iocb, sk, msg, len);
1015 
1016 	/* Rough check on arithmetic overflow,
1017 	   better check is made in ip6_append_data().
1018 	   */
1019 	if (len > INT_MAX - sizeof(struct udphdr))
1020 		return -EMSGSIZE;
1021 
1022 	if (up->pending) {
1023 		/*
1024 		 * There are pending frames.
1025 		 * The socket lock must be held while it's corked.
1026 		 */
1027 		lock_sock(sk);
1028 		if (likely(up->pending)) {
1029 			if (unlikely(up->pending != AF_INET6)) {
1030 				release_sock(sk);
1031 				return -EAFNOSUPPORT;
1032 			}
1033 			dst = NULL;
1034 			goto do_append_data;
1035 		}
1036 		release_sock(sk);
1037 	}
1038 	ulen += sizeof(struct udphdr);
1039 
1040 	memset(&fl6, 0, sizeof(fl6));
1041 
1042 	if (sin6) {
1043 		if (sin6->sin6_port == 0)
1044 			return -EINVAL;
1045 
1046 		fl6.fl6_dport = sin6->sin6_port;
1047 		daddr = &sin6->sin6_addr;
1048 
1049 		if (np->sndflow) {
1050 			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1051 			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1052 				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1053 				if (flowlabel == NULL)
1054 					return -EINVAL;
1055 				daddr = &flowlabel->dst;
1056 			}
1057 		}
1058 
1059 		/*
1060 		 * Otherwise it will be difficult to maintain
1061 		 * sk->sk_dst_cache.
1062 		 */
1063 		if (sk->sk_state == TCP_ESTABLISHED &&
1064 		    ipv6_addr_equal(daddr, &np->daddr))
1065 			daddr = &np->daddr;
1066 
1067 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1068 		    sin6->sin6_scope_id &&
1069 		    ipv6_addr_type(daddr)&IPV6_ADDR_LINKLOCAL)
1070 			fl6.flowi6_oif = sin6->sin6_scope_id;
1071 	} else {
1072 		if (sk->sk_state != TCP_ESTABLISHED)
1073 			return -EDESTADDRREQ;
1074 
1075 		fl6.fl6_dport = inet->inet_dport;
1076 		daddr = &np->daddr;
1077 		fl6.flowlabel = np->flow_label;
1078 		connected = 1;
1079 	}
1080 
1081 	if (!fl6.flowi6_oif)
1082 		fl6.flowi6_oif = sk->sk_bound_dev_if;
1083 
1084 	if (!fl6.flowi6_oif)
1085 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1086 
1087 	fl6.flowi6_mark = sk->sk_mark;
1088 
1089 	if (msg->msg_controllen) {
1090 		opt = &opt_space;
1091 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1092 		opt->tot_len = sizeof(*opt);
1093 
1094 		err = datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
1095 					&hlimit, &tclass, &dontfrag);
1096 		if (err < 0) {
1097 			fl6_sock_release(flowlabel);
1098 			return err;
1099 		}
1100 		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1101 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1102 			if (flowlabel == NULL)
1103 				return -EINVAL;
1104 		}
1105 		if (!(opt->opt_nflen|opt->opt_flen))
1106 			opt = NULL;
1107 		connected = 0;
1108 	}
1109 	if (opt == NULL)
1110 		opt = np->opt;
1111 	if (flowlabel)
1112 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1113 	opt = ipv6_fixup_options(&opt_space, opt);
1114 
1115 	fl6.flowi6_proto = sk->sk_protocol;
1116 	if (!ipv6_addr_any(daddr))
1117 		ipv6_addr_copy(&fl6.daddr, daddr);
1118 	else
1119 		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1120 	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1121 		ipv6_addr_copy(&fl6.saddr, &np->saddr);
1122 	fl6.fl6_sport = inet->inet_sport;
1123 
1124 	final_p = fl6_update_dst(&fl6, opt, &final);
1125 	if (final_p)
1126 		connected = 0;
1127 
1128 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1129 		fl6.flowi6_oif = np->mcast_oif;
1130 		connected = 0;
1131 	}
1132 
1133 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1134 
1135 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p, true);
1136 	if (IS_ERR(dst)) {
1137 		err = PTR_ERR(dst);
1138 		dst = NULL;
1139 		goto out;
1140 	}
1141 
1142 	if (hlimit < 0) {
1143 		if (ipv6_addr_is_multicast(&fl6.daddr))
1144 			hlimit = np->mcast_hops;
1145 		else
1146 			hlimit = np->hop_limit;
1147 		if (hlimit < 0)
1148 			hlimit = ip6_dst_hoplimit(dst);
1149 	}
1150 
1151 	if (tclass < 0)
1152 		tclass = np->tclass;
1153 
1154 	if (dontfrag < 0)
1155 		dontfrag = np->dontfrag;
1156 
1157 	if (msg->msg_flags&MSG_CONFIRM)
1158 		goto do_confirm;
1159 back_from_confirm:
1160 
1161 	lock_sock(sk);
1162 	if (unlikely(up->pending)) {
1163 		/* The socket is already corked while preparing it. */
1164 		/* ... which is an evident application bug. --ANK */
1165 		release_sock(sk);
1166 
1167 		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
1168 		err = -EINVAL;
1169 		goto out;
1170 	}
1171 
1172 	up->pending = AF_INET6;
1173 
1174 do_append_data:
1175 	up->len += ulen;
1176 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1177 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
1178 		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
1179 		(struct rt6_info*)dst,
1180 		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
1181 	if (err)
1182 		udp_v6_flush_pending_frames(sk);
1183 	else if (!corkreq)
1184 		err = udp_v6_push_pending_frames(sk);
1185 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1186 		up->pending = 0;
1187 
1188 	if (dst) {
1189 		if (connected) {
1190 			ip6_dst_store(sk, dst,
1191 				      ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
1192 				      &np->daddr : NULL,
1193 #ifdef CONFIG_IPV6_SUBTREES
1194 				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1195 				      &np->saddr :
1196 #endif
1197 				      NULL);
1198 		} else {
1199 			dst_release(dst);
1200 		}
1201 		dst = NULL;
1202 	}
1203 
1204 	if (err > 0)
1205 		err = np->recverr ? net_xmit_errno(err) : 0;
1206 	release_sock(sk);
1207 out:
1208 	dst_release(dst);
1209 	fl6_sock_release(flowlabel);
1210 	if (!err)
1211 		return len;
1212 	/*
1213 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1214 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1215 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1216 	 * things).  We could add another new stat but at least for now that
1217 	 * seems like overkill.
1218 	 */
1219 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1220 		UDP6_INC_STATS_USER(sock_net(sk),
1221 				UDP_MIB_SNDBUFERRORS, is_udplite);
1222 	}
1223 	return err;
1224 
1225 do_confirm:
1226 	dst_confirm(dst);
1227 	if (!(msg->msg_flags&MSG_PROBE) || len)
1228 		goto back_from_confirm;
1229 	err = 0;
1230 	goto out;
1231 }
1232 
1233 void udpv6_destroy_sock(struct sock *sk)
1234 {
1235 	lock_sock(sk);
1236 	udp_v6_flush_pending_frames(sk);
1237 	release_sock(sk);
1238 
1239 	inet6_destroy_sock(sk);
1240 }
1241 
1242 /*
1243  *	Socket option code for UDP
1244  */
1245 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1246 		     char __user *optval, unsigned int optlen)
1247 {
1248 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1249 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1250 					  udp_v6_push_pending_frames);
1251 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1252 }
1253 
1254 #ifdef CONFIG_COMPAT
1255 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1256 			    char __user *optval, unsigned int optlen)
1257 {
1258 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1259 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1260 					  udp_v6_push_pending_frames);
1261 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1262 }
1263 #endif
1264 
1265 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1266 		     char __user *optval, int __user *optlen)
1267 {
1268 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1269 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1270 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1271 }
1272 
1273 #ifdef CONFIG_COMPAT
1274 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1275 			    char __user *optval, int __user *optlen)
1276 {
1277 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1278 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1279 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1280 }
1281 #endif
1282 
1283 static int udp6_ufo_send_check(struct sk_buff *skb)
1284 {
1285 	const struct ipv6hdr *ipv6h;
1286 	struct udphdr *uh;
1287 
1288 	if (!pskb_may_pull(skb, sizeof(*uh)))
1289 		return -EINVAL;
1290 
1291 	ipv6h = ipv6_hdr(skb);
1292 	uh = udp_hdr(skb);
1293 
1294 	uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
1295 				     IPPROTO_UDP, 0);
1296 	skb->csum_start = skb_transport_header(skb) - skb->head;
1297 	skb->csum_offset = offsetof(struct udphdr, check);
1298 	skb->ip_summed = CHECKSUM_PARTIAL;
1299 	return 0;
1300 }
1301 
1302 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, u32 features)
1303 {
1304 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1305 	unsigned int mss;
1306 	unsigned int unfrag_ip6hlen, unfrag_len;
1307 	struct frag_hdr *fptr;
1308 	u8 *mac_start, *prevhdr;
1309 	u8 nexthdr;
1310 	u8 frag_hdr_sz = sizeof(struct frag_hdr);
1311 	int offset;
1312 	__wsum csum;
1313 
1314 	mss = skb_shinfo(skb)->gso_size;
1315 	if (unlikely(skb->len <= mss))
1316 		goto out;
1317 
1318 	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
1319 		/* Packet is from an untrusted source, reset gso_segs. */
1320 		int type = skb_shinfo(skb)->gso_type;
1321 
1322 		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
1323 			     !(type & (SKB_GSO_UDP))))
1324 			goto out;
1325 
1326 		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
1327 
1328 		segs = NULL;
1329 		goto out;
1330 	}
1331 
1332 	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
1333 	 * do checksum of UDP packets sent as multiple IP fragments.
1334 	 */
1335 	offset = skb_checksum_start_offset(skb);
1336 	csum = skb_checksum(skb, offset, skb->len- offset, 0);
1337 	offset += skb->csum_offset;
1338 	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
1339 	skb->ip_summed = CHECKSUM_NONE;
1340 
1341 	/* Check if there is enough headroom to insert fragment header. */
1342 	if ((skb_mac_header(skb) < skb->head + frag_hdr_sz) &&
1343 	    pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
1344 		goto out;
1345 
1346 	/* Find the unfragmentable header and shift it left by frag_hdr_sz
1347 	 * bytes to insert fragment header.
1348 	 */
1349 	unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
1350 	nexthdr = *prevhdr;
1351 	*prevhdr = NEXTHDR_FRAGMENT;
1352 	unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
1353 		     unfrag_ip6hlen;
1354 	mac_start = skb_mac_header(skb);
1355 	memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
1356 
1357 	skb->mac_header -= frag_hdr_sz;
1358 	skb->network_header -= frag_hdr_sz;
1359 
1360 	fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
1361 	fptr->nexthdr = nexthdr;
1362 	fptr->reserved = 0;
1363 	ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));
1364 
1365 	/* Fragment the skb. ipv6 header and the remaining fields of the
1366 	 * fragment header are updated in ipv6_gso_segment()
1367 	 */
1368 	segs = skb_segment(skb, features);
1369 
1370 out:
1371 	return segs;
1372 }
1373 
1374 static const struct inet6_protocol udpv6_protocol = {
1375 	.handler	=	udpv6_rcv,
1376 	.err_handler	=	udpv6_err,
1377 	.gso_send_check =	udp6_ufo_send_check,
1378 	.gso_segment	=	udp6_ufo_fragment,
1379 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1380 };
1381 
1382 /* ------------------------------------------------------------------------ */
1383 #ifdef CONFIG_PROC_FS
1384 
1385 static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket)
1386 {
1387 	struct inet_sock *inet = inet_sk(sp);
1388 	struct ipv6_pinfo *np = inet6_sk(sp);
1389 	const struct in6_addr *dest, *src;
1390 	__u16 destp, srcp;
1391 
1392 	dest  = &np->daddr;
1393 	src   = &np->rcv_saddr;
1394 	destp = ntohs(inet->inet_dport);
1395 	srcp  = ntohs(inet->inet_sport);
1396 	seq_printf(seq,
1397 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1398 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
1399 		   bucket,
1400 		   src->s6_addr32[0], src->s6_addr32[1],
1401 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1402 		   dest->s6_addr32[0], dest->s6_addr32[1],
1403 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1404 		   sp->sk_state,
1405 		   sk_wmem_alloc_get(sp),
1406 		   sk_rmem_alloc_get(sp),
1407 		   0, 0L, 0,
1408 		   sock_i_uid(sp), 0,
1409 		   sock_i_ino(sp),
1410 		   atomic_read(&sp->sk_refcnt), sp,
1411 		   atomic_read(&sp->sk_drops));
1412 }
1413 
1414 int udp6_seq_show(struct seq_file *seq, void *v)
1415 {
1416 	if (v == SEQ_START_TOKEN)
1417 		seq_printf(seq,
1418 			   "  sl  "
1419 			   "local_address                         "
1420 			   "remote_address                        "
1421 			   "st tx_queue rx_queue tr tm->when retrnsmt"
1422 			   "   uid  timeout inode ref pointer drops\n");
1423 	else
1424 		udp6_sock_seq_show(seq, v, ((struct udp_iter_state *)seq->private)->bucket);
1425 	return 0;
1426 }
1427 
1428 static const struct file_operations udp6_afinfo_seq_fops = {
1429 	.owner    = THIS_MODULE,
1430 	.open     = udp_seq_open,
1431 	.read     = seq_read,
1432 	.llseek   = seq_lseek,
1433 	.release  = seq_release_net
1434 };
1435 
1436 static struct udp_seq_afinfo udp6_seq_afinfo = {
1437 	.name		= "udp6",
1438 	.family		= AF_INET6,
1439 	.udp_table	= &udp_table,
1440 	.seq_fops	= &udp6_afinfo_seq_fops,
1441 	.seq_ops	= {
1442 		.show		= udp6_seq_show,
1443 	},
1444 };
1445 
1446 int __net_init udp6_proc_init(struct net *net)
1447 {
1448 	return udp_proc_register(net, &udp6_seq_afinfo);
1449 }
1450 
1451 void udp6_proc_exit(struct net *net) {
1452 	udp_proc_unregister(net, &udp6_seq_afinfo);
1453 }
1454 #endif /* CONFIG_PROC_FS */
1455 
1456 /* ------------------------------------------------------------------------ */
1457 
1458 struct proto udpv6_prot = {
1459 	.name		   = "UDPv6",
1460 	.owner		   = THIS_MODULE,
1461 	.close		   = udp_lib_close,
1462 	.connect	   = ip6_datagram_connect,
1463 	.disconnect	   = udp_disconnect,
1464 	.ioctl		   = udp_ioctl,
1465 	.destroy	   = udpv6_destroy_sock,
1466 	.setsockopt	   = udpv6_setsockopt,
1467 	.getsockopt	   = udpv6_getsockopt,
1468 	.sendmsg	   = udpv6_sendmsg,
1469 	.recvmsg	   = udpv6_recvmsg,
1470 	.backlog_rcv	   = udpv6_queue_rcv_skb,
1471 	.hash		   = udp_lib_hash,
1472 	.unhash		   = udp_lib_unhash,
1473 	.rehash		   = udp_v6_rehash,
1474 	.get_port	   = udp_v6_get_port,
1475 	.memory_allocated  = &udp_memory_allocated,
1476 	.sysctl_mem	   = sysctl_udp_mem,
1477 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1478 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1479 	.obj_size	   = sizeof(struct udp6_sock),
1480 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1481 	.h.udp_table	   = &udp_table,
1482 #ifdef CONFIG_COMPAT
1483 	.compat_setsockopt = compat_udpv6_setsockopt,
1484 	.compat_getsockopt = compat_udpv6_getsockopt,
1485 #endif
1486 	.clear_sk	   = sk_prot_clear_portaddr_nulls,
1487 };
1488 
1489 static struct inet_protosw udpv6_protosw = {
1490 	.type =      SOCK_DGRAM,
1491 	.protocol =  IPPROTO_UDP,
1492 	.prot =      &udpv6_prot,
1493 	.ops =       &inet6_dgram_ops,
1494 	.no_check =  UDP_CSUM_DEFAULT,
1495 	.flags =     INET_PROTOSW_PERMANENT,
1496 };
1497 
1498 
1499 int __init udpv6_init(void)
1500 {
1501 	int ret;
1502 
1503 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1504 	if (ret)
1505 		goto out;
1506 
1507 	ret = inet6_register_protosw(&udpv6_protosw);
1508 	if (ret)
1509 		goto out_udpv6_protocol;
1510 out:
1511 	return ret;
1512 
1513 out_udpv6_protocol:
1514 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1515 	goto out;
1516 }
1517 
1518 void udpv6_exit(void)
1519 {
1520 	inet6_unregister_protosw(&udpv6_protosw);
1521 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1522 }
1523