xref: /openbmc/linux/net/ipv6/udp.c (revision e4c0d0e2)
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;
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 	if (len > ulen)
367 		len = ulen;
368 	else if (len < ulen)
369 		msg->msg_flags |= MSG_TRUNC;
370 
371 	is_udp4 = (skb->protocol == htons(ETH_P_IP));
372 
373 	/*
374 	 * If checksum is needed at all, try to do it while copying the
375 	 * data.  If the data is truncated, or if we only want a partial
376 	 * coverage checksum (UDP-Lite), do it before the copy.
377 	 */
378 
379 	if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
380 		if (udp_lib_checksum_complete(skb))
381 			goto csum_copy_err;
382 	}
383 
384 	if (skb_csum_unnecessary(skb))
385 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
386 					      msg->msg_iov,len);
387 	else {
388 		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
389 		if (err == -EINVAL)
390 			goto csum_copy_err;
391 	}
392 	if (err)
393 		goto out_free;
394 
395 	if (!peeked) {
396 		if (is_udp4)
397 			UDP_INC_STATS_USER(sock_net(sk),
398 					UDP_MIB_INDATAGRAMS, is_udplite);
399 		else
400 			UDP6_INC_STATS_USER(sock_net(sk),
401 					UDP_MIB_INDATAGRAMS, is_udplite);
402 	}
403 
404 	sock_recv_ts_and_drops(msg, sk, skb);
405 
406 	/* Copy the address. */
407 	if (msg->msg_name) {
408 		struct sockaddr_in6 *sin6;
409 
410 		sin6 = (struct sockaddr_in6 *) msg->msg_name;
411 		sin6->sin6_family = AF_INET6;
412 		sin6->sin6_port = udp_hdr(skb)->source;
413 		sin6->sin6_flowinfo = 0;
414 		sin6->sin6_scope_id = 0;
415 
416 		if (is_udp4)
417 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
418 					       &sin6->sin6_addr);
419 		else {
420 			ipv6_addr_copy(&sin6->sin6_addr,
421 				       &ipv6_hdr(skb)->saddr);
422 			if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
423 				sin6->sin6_scope_id = IP6CB(skb)->iif;
424 		}
425 
426 	}
427 	if (is_udp4) {
428 		if (inet->cmsg_flags)
429 			ip_cmsg_recv(msg, skb);
430 	} else {
431 		if (np->rxopt.all)
432 			datagram_recv_ctl(sk, msg, skb);
433 	}
434 
435 	err = len;
436 	if (flags & MSG_TRUNC)
437 		err = ulen;
438 
439 out_free:
440 	skb_free_datagram_locked(sk, skb);
441 out:
442 	return err;
443 
444 csum_copy_err:
445 	slow = lock_sock_fast(sk);
446 	if (!skb_kill_datagram(sk, skb, flags)) {
447 		if (is_udp4)
448 			UDP_INC_STATS_USER(sock_net(sk),
449 					UDP_MIB_INERRORS, is_udplite);
450 		else
451 			UDP6_INC_STATS_USER(sock_net(sk),
452 					UDP_MIB_INERRORS, is_udplite);
453 	}
454 	unlock_sock_fast(sk, slow);
455 
456 	if (noblock)
457 		return -EAGAIN;
458 
459 	/* starting over for a new packet */
460 	msg->msg_flags &= ~MSG_TRUNC;
461 	goto try_again;
462 }
463 
464 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
465 		    u8 type, u8 code, int offset, __be32 info,
466 		    struct udp_table *udptable)
467 {
468 	struct ipv6_pinfo *np;
469 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
470 	const struct in6_addr *saddr = &hdr->saddr;
471 	const struct in6_addr *daddr = &hdr->daddr;
472 	struct udphdr *uh = (struct udphdr*)(skb->data+offset);
473 	struct sock *sk;
474 	int err;
475 
476 	sk = __udp6_lib_lookup(dev_net(skb->dev), daddr, uh->dest,
477 			       saddr, uh->source, inet6_iif(skb), udptable);
478 	if (sk == NULL)
479 		return;
480 
481 	np = inet6_sk(sk);
482 
483 	if (!icmpv6_err_convert(type, code, &err) && !np->recverr)
484 		goto out;
485 
486 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
487 		goto out;
488 
489 	if (np->recverr)
490 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
491 
492 	sk->sk_err = err;
493 	sk->sk_error_report(sk);
494 out:
495 	sock_put(sk);
496 }
497 
498 static __inline__ void udpv6_err(struct sk_buff *skb,
499 				 struct inet6_skb_parm *opt, u8 type,
500 				 u8 code, int offset, __be32 info     )
501 {
502 	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
503 }
504 
505 int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
506 {
507 	struct udp_sock *up = udp_sk(sk);
508 	int rc;
509 	int is_udplite = IS_UDPLITE(sk);
510 
511 	if (!ipv6_addr_any(&inet6_sk(sk)->daddr))
512 		sock_rps_save_rxhash(sk, skb->rxhash);
513 
514 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
515 		goto drop;
516 
517 	/*
518 	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
519 	 */
520 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
521 
522 		if (up->pcrlen == 0) {          /* full coverage was set  */
523 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: partial coverage"
524 				" %d while full coverage %d requested\n",
525 				UDP_SKB_CB(skb)->cscov, skb->len);
526 			goto drop;
527 		}
528 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
529 			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE6: coverage %d "
530 						    "too small, need min %d\n",
531 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
532 			goto drop;
533 		}
534 	}
535 
536 	if (rcu_dereference_raw(sk->sk_filter)) {
537 		if (udp_lib_checksum_complete(skb))
538 			goto drop;
539 	}
540 
541 	if ((rc = ip_queue_rcv_skb(sk, skb)) < 0) {
542 		/* Note that an ENOMEM error is charged twice */
543 		if (rc == -ENOMEM)
544 			UDP6_INC_STATS_BH(sock_net(sk),
545 					UDP_MIB_RCVBUFERRORS, is_udplite);
546 		goto drop_no_sk_drops_inc;
547 	}
548 
549 	return 0;
550 drop:
551 	atomic_inc(&sk->sk_drops);
552 drop_no_sk_drops_inc:
553 	UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
554 	kfree_skb(skb);
555 	return -1;
556 }
557 
558 static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
559 				      __be16 loc_port, const struct in6_addr *loc_addr,
560 				      __be16 rmt_port, const struct in6_addr *rmt_addr,
561 				      int dif)
562 {
563 	struct hlist_nulls_node *node;
564 	struct sock *s = sk;
565 	unsigned short num = ntohs(loc_port);
566 
567 	sk_nulls_for_each_from(s, node) {
568 		struct inet_sock *inet = inet_sk(s);
569 
570 		if (!net_eq(sock_net(s), net))
571 			continue;
572 
573 		if (udp_sk(s)->udp_port_hash == num &&
574 		    s->sk_family == PF_INET6) {
575 			struct ipv6_pinfo *np = inet6_sk(s);
576 			if (inet->inet_dport) {
577 				if (inet->inet_dport != rmt_port)
578 					continue;
579 			}
580 			if (!ipv6_addr_any(&np->daddr) &&
581 			    !ipv6_addr_equal(&np->daddr, rmt_addr))
582 				continue;
583 
584 			if (s->sk_bound_dev_if && s->sk_bound_dev_if != dif)
585 				continue;
586 
587 			if (!ipv6_addr_any(&np->rcv_saddr)) {
588 				if (!ipv6_addr_equal(&np->rcv_saddr, loc_addr))
589 					continue;
590 			}
591 			if (!inet6_mc_check(s, loc_addr, rmt_addr))
592 				continue;
593 			return s;
594 		}
595 	}
596 	return NULL;
597 }
598 
599 static void flush_stack(struct sock **stack, unsigned int count,
600 			struct sk_buff *skb, unsigned int final)
601 {
602 	unsigned int i;
603 	struct sock *sk;
604 	struct sk_buff *skb1;
605 
606 	for (i = 0; i < count; i++) {
607 		skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
608 
609 		sk = stack[i];
610 		if (skb1) {
611 			if (sk_rcvqueues_full(sk, skb1)) {
612 				kfree_skb(skb1);
613 				goto drop;
614 			}
615 			bh_lock_sock(sk);
616 			if (!sock_owned_by_user(sk))
617 				udpv6_queue_rcv_skb(sk, skb1);
618 			else if (sk_add_backlog(sk, skb1)) {
619 				kfree_skb(skb1);
620 				bh_unlock_sock(sk);
621 				goto drop;
622 			}
623 			bh_unlock_sock(sk);
624 			continue;
625 		}
626 drop:
627 		atomic_inc(&sk->sk_drops);
628 		UDP6_INC_STATS_BH(sock_net(sk),
629 				UDP_MIB_RCVBUFERRORS, IS_UDPLITE(sk));
630 		UDP6_INC_STATS_BH(sock_net(sk),
631 				UDP_MIB_INERRORS, IS_UDPLITE(sk));
632 	}
633 }
634 /*
635  * Note: called only from the BH handler context,
636  * so we don't need to lock the hashes.
637  */
638 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
639 		const struct in6_addr *saddr, const struct in6_addr *daddr,
640 		struct udp_table *udptable)
641 {
642 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
643 	const struct udphdr *uh = udp_hdr(skb);
644 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
645 	int dif;
646 	unsigned int i, count = 0;
647 
648 	spin_lock(&hslot->lock);
649 	sk = sk_nulls_head(&hslot->head);
650 	dif = inet6_iif(skb);
651 	sk = udp_v6_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
652 	while (sk) {
653 		stack[count++] = sk;
654 		sk = udp_v6_mcast_next(net, sk_nulls_next(sk), uh->dest, daddr,
655 				       uh->source, saddr, dif);
656 		if (unlikely(count == ARRAY_SIZE(stack))) {
657 			if (!sk)
658 				break;
659 			flush_stack(stack, count, skb, ~0);
660 			count = 0;
661 		}
662 	}
663 	/*
664 	 * before releasing the lock, we must take reference on sockets
665 	 */
666 	for (i = 0; i < count; i++)
667 		sock_hold(stack[i]);
668 
669 	spin_unlock(&hslot->lock);
670 
671 	if (count) {
672 		flush_stack(stack, count, skb, count - 1);
673 
674 		for (i = 0; i < count; i++)
675 			sock_put(stack[i]);
676 	} else {
677 		kfree_skb(skb);
678 	}
679 	return 0;
680 }
681 
682 static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
683 				 int proto)
684 {
685 	int err;
686 
687 	UDP_SKB_CB(skb)->partial_cov = 0;
688 	UDP_SKB_CB(skb)->cscov = skb->len;
689 
690 	if (proto == IPPROTO_UDPLITE) {
691 		err = udplite_checksum_init(skb, uh);
692 		if (err)
693 			return err;
694 	}
695 
696 	if (uh->check == 0) {
697 		/* RFC 2460 section 8.1 says that we SHOULD log
698 		   this error. Well, it is reasonable.
699 		 */
700 		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0\n");
701 		return 1;
702 	}
703 	if (skb->ip_summed == CHECKSUM_COMPLETE &&
704 	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
705 			     skb->len, proto, skb->csum))
706 		skb->ip_summed = CHECKSUM_UNNECESSARY;
707 
708 	if (!skb_csum_unnecessary(skb))
709 		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
710 							 &ipv6_hdr(skb)->daddr,
711 							 skb->len, proto, 0));
712 
713 	return 0;
714 }
715 
716 int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
717 		   int proto)
718 {
719 	struct net *net = dev_net(skb->dev);
720 	struct sock *sk;
721 	struct udphdr *uh;
722 	const struct in6_addr *saddr, *daddr;
723 	u32 ulen = 0;
724 
725 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
726 		goto discard;
727 
728 	saddr = &ipv6_hdr(skb)->saddr;
729 	daddr = &ipv6_hdr(skb)->daddr;
730 	uh = udp_hdr(skb);
731 
732 	ulen = ntohs(uh->len);
733 	if (ulen > skb->len)
734 		goto short_packet;
735 
736 	if (proto == IPPROTO_UDP) {
737 		/* UDP validates ulen. */
738 
739 		/* Check for jumbo payload */
740 		if (ulen == 0)
741 			ulen = skb->len;
742 
743 		if (ulen < sizeof(*uh))
744 			goto short_packet;
745 
746 		if (ulen < skb->len) {
747 			if (pskb_trim_rcsum(skb, ulen))
748 				goto short_packet;
749 			saddr = &ipv6_hdr(skb)->saddr;
750 			daddr = &ipv6_hdr(skb)->daddr;
751 			uh = udp_hdr(skb);
752 		}
753 	}
754 
755 	if (udp6_csum_init(skb, uh, proto))
756 		goto discard;
757 
758 	/*
759 	 *	Multicast receive code
760 	 */
761 	if (ipv6_addr_is_multicast(daddr))
762 		return __udp6_lib_mcast_deliver(net, skb,
763 				saddr, daddr, udptable);
764 
765 	/* Unicast */
766 
767 	/*
768 	 * check socket cache ... must talk to Alan about his plans
769 	 * for sock caches... i'll skip this for now.
770 	 */
771 	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
772 
773 	if (sk == NULL) {
774 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
775 			goto discard;
776 
777 		if (udp_lib_checksum_complete(skb))
778 			goto discard;
779 		UDP6_INC_STATS_BH(net, UDP_MIB_NOPORTS,
780 				proto == IPPROTO_UDPLITE);
781 
782 		icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
783 
784 		kfree_skb(skb);
785 		return 0;
786 	}
787 
788 	/* deliver */
789 
790 	if (sk_rcvqueues_full(sk, skb)) {
791 		sock_put(sk);
792 		goto discard;
793 	}
794 	bh_lock_sock(sk);
795 	if (!sock_owned_by_user(sk))
796 		udpv6_queue_rcv_skb(sk, skb);
797 	else if (sk_add_backlog(sk, skb)) {
798 		atomic_inc(&sk->sk_drops);
799 		bh_unlock_sock(sk);
800 		sock_put(sk);
801 		goto discard;
802 	}
803 	bh_unlock_sock(sk);
804 	sock_put(sk);
805 	return 0;
806 
807 short_packet:
808 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
809 		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
810 		       saddr,
811 		       ntohs(uh->source),
812 		       ulen,
813 		       skb->len,
814 		       daddr,
815 		       ntohs(uh->dest));
816 
817 discard:
818 	UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
819 	kfree_skb(skb);
820 	return 0;
821 }
822 
823 static __inline__ int udpv6_rcv(struct sk_buff *skb)
824 {
825 	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
826 }
827 
828 /*
829  * Throw away all pending data and cancel the corking. Socket is locked.
830  */
831 static void udp_v6_flush_pending_frames(struct sock *sk)
832 {
833 	struct udp_sock *up = udp_sk(sk);
834 
835 	if (up->pending == AF_INET)
836 		udp_flush_pending_frames(sk);
837 	else if (up->pending) {
838 		up->len = 0;
839 		up->pending = 0;
840 		ip6_flush_pending_frames(sk);
841 	}
842 }
843 
844 /**
845  * 	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
846  * 	@sk: 	socket we are sending on
847  * 	@skb: 	sk_buff containing the filled-in UDP header
848  * 	        (checksum field must be zeroed out)
849  */
850 static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
851 				 const struct in6_addr *saddr,
852 				 const struct in6_addr *daddr, int len)
853 {
854 	unsigned int offset;
855 	struct udphdr *uh = udp_hdr(skb);
856 	__wsum csum = 0;
857 
858 	if (skb_queue_len(&sk->sk_write_queue) == 1) {
859 		/* Only one fragment on the socket.  */
860 		skb->csum_start = skb_transport_header(skb) - skb->head;
861 		skb->csum_offset = offsetof(struct udphdr, check);
862 		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
863 	} else {
864 		/*
865 		 * HW-checksum won't work as there are two or more
866 		 * fragments on the socket so that all csums of sk_buffs
867 		 * should be together
868 		 */
869 		offset = skb_transport_offset(skb);
870 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
871 
872 		skb->ip_summed = CHECKSUM_NONE;
873 
874 		skb_queue_walk(&sk->sk_write_queue, skb) {
875 			csum = csum_add(csum, skb->csum);
876 		}
877 
878 		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
879 					    csum);
880 		if (uh->check == 0)
881 			uh->check = CSUM_MANGLED_0;
882 	}
883 }
884 
885 /*
886  *	Sending
887  */
888 
889 static int udp_v6_push_pending_frames(struct sock *sk)
890 {
891 	struct sk_buff *skb;
892 	struct udphdr *uh;
893 	struct udp_sock  *up = udp_sk(sk);
894 	struct inet_sock *inet = inet_sk(sk);
895 	struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
896 	int err = 0;
897 	int is_udplite = IS_UDPLITE(sk);
898 	__wsum csum = 0;
899 
900 	/* Grab the skbuff where UDP header space exists. */
901 	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
902 		goto out;
903 
904 	/*
905 	 * Create a UDP header
906 	 */
907 	uh = udp_hdr(skb);
908 	uh->source = fl6->fl6_sport;
909 	uh->dest = fl6->fl6_dport;
910 	uh->len = htons(up->len);
911 	uh->check = 0;
912 
913 	if (is_udplite)
914 		csum = udplite_csum_outgoing(sk, skb);
915 	else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
916 		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr,
917 				     up->len);
918 		goto send;
919 	} else
920 		csum = udp_csum_outgoing(sk, skb);
921 
922 	/* add protocol-dependent pseudo-header */
923 	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
924 				    up->len, fl6->flowi6_proto, csum);
925 	if (uh->check == 0)
926 		uh->check = CSUM_MANGLED_0;
927 
928 send:
929 	err = ip6_push_pending_frames(sk);
930 	if (err) {
931 		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
932 			UDP6_INC_STATS_USER(sock_net(sk),
933 					    UDP_MIB_SNDBUFERRORS, is_udplite);
934 			err = 0;
935 		}
936 	} else
937 		UDP6_INC_STATS_USER(sock_net(sk),
938 				    UDP_MIB_OUTDATAGRAMS, is_udplite);
939 out:
940 	up->len = 0;
941 	up->pending = 0;
942 	return err;
943 }
944 
945 int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
946 		  struct msghdr *msg, size_t len)
947 {
948 	struct ipv6_txoptions opt_space;
949 	struct udp_sock *up = udp_sk(sk);
950 	struct inet_sock *inet = inet_sk(sk);
951 	struct ipv6_pinfo *np = inet6_sk(sk);
952 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
953 	struct in6_addr *daddr, *final_p, final;
954 	struct ipv6_txoptions *opt = NULL;
955 	struct ip6_flowlabel *flowlabel = NULL;
956 	struct flowi6 fl6;
957 	struct dst_entry *dst;
958 	int addr_len = msg->msg_namelen;
959 	int ulen = len;
960 	int hlimit = -1;
961 	int tclass = -1;
962 	int dontfrag = -1;
963 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
964 	int err;
965 	int connected = 0;
966 	int is_udplite = IS_UDPLITE(sk);
967 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
968 
969 	/* destination address check */
970 	if (sin6) {
971 		if (addr_len < offsetof(struct sockaddr, sa_data))
972 			return -EINVAL;
973 
974 		switch (sin6->sin6_family) {
975 		case AF_INET6:
976 			if (addr_len < SIN6_LEN_RFC2133)
977 				return -EINVAL;
978 			daddr = &sin6->sin6_addr;
979 			break;
980 		case AF_INET:
981 			goto do_udp_sendmsg;
982 		case AF_UNSPEC:
983 			msg->msg_name = sin6 = NULL;
984 			msg->msg_namelen = addr_len = 0;
985 			daddr = NULL;
986 			break;
987 		default:
988 			return -EINVAL;
989 		}
990 	} else if (!up->pending) {
991 		if (sk->sk_state != TCP_ESTABLISHED)
992 			return -EDESTADDRREQ;
993 		daddr = &np->daddr;
994 	} else
995 		daddr = NULL;
996 
997 	if (daddr) {
998 		if (ipv6_addr_v4mapped(daddr)) {
999 			struct sockaddr_in sin;
1000 			sin.sin_family = AF_INET;
1001 			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
1002 			sin.sin_addr.s_addr = daddr->s6_addr32[3];
1003 			msg->msg_name = &sin;
1004 			msg->msg_namelen = sizeof(sin);
1005 do_udp_sendmsg:
1006 			if (__ipv6_only_sock(sk))
1007 				return -ENETUNREACH;
1008 			return udp_sendmsg(iocb, sk, msg, len);
1009 		}
1010 	}
1011 
1012 	if (up->pending == AF_INET)
1013 		return udp_sendmsg(iocb, sk, msg, len);
1014 
1015 	/* Rough check on arithmetic overflow,
1016 	   better check is made in ip6_append_data().
1017 	   */
1018 	if (len > INT_MAX - sizeof(struct udphdr))
1019 		return -EMSGSIZE;
1020 
1021 	if (up->pending) {
1022 		/*
1023 		 * There are pending frames.
1024 		 * The socket lock must be held while it's corked.
1025 		 */
1026 		lock_sock(sk);
1027 		if (likely(up->pending)) {
1028 			if (unlikely(up->pending != AF_INET6)) {
1029 				release_sock(sk);
1030 				return -EAFNOSUPPORT;
1031 			}
1032 			dst = NULL;
1033 			goto do_append_data;
1034 		}
1035 		release_sock(sk);
1036 	}
1037 	ulen += sizeof(struct udphdr);
1038 
1039 	memset(&fl6, 0, sizeof(fl6));
1040 
1041 	if (sin6) {
1042 		if (sin6->sin6_port == 0)
1043 			return -EINVAL;
1044 
1045 		fl6.fl6_dport = sin6->sin6_port;
1046 		daddr = &sin6->sin6_addr;
1047 
1048 		if (np->sndflow) {
1049 			fl6.flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
1050 			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
1051 				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1052 				if (flowlabel == NULL)
1053 					return -EINVAL;
1054 				daddr = &flowlabel->dst;
1055 			}
1056 		}
1057 
1058 		/*
1059 		 * Otherwise it will be difficult to maintain
1060 		 * sk->sk_dst_cache.
1061 		 */
1062 		if (sk->sk_state == TCP_ESTABLISHED &&
1063 		    ipv6_addr_equal(daddr, &np->daddr))
1064 			daddr = &np->daddr;
1065 
1066 		if (addr_len >= sizeof(struct sockaddr_in6) &&
1067 		    sin6->sin6_scope_id &&
1068 		    ipv6_addr_type(daddr)&IPV6_ADDR_LINKLOCAL)
1069 			fl6.flowi6_oif = sin6->sin6_scope_id;
1070 	} else {
1071 		if (sk->sk_state != TCP_ESTABLISHED)
1072 			return -EDESTADDRREQ;
1073 
1074 		fl6.fl6_dport = inet->inet_dport;
1075 		daddr = &np->daddr;
1076 		fl6.flowlabel = np->flow_label;
1077 		connected = 1;
1078 	}
1079 
1080 	if (!fl6.flowi6_oif)
1081 		fl6.flowi6_oif = sk->sk_bound_dev_if;
1082 
1083 	if (!fl6.flowi6_oif)
1084 		fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
1085 
1086 	fl6.flowi6_mark = sk->sk_mark;
1087 
1088 	if (msg->msg_controllen) {
1089 		opt = &opt_space;
1090 		memset(opt, 0, sizeof(struct ipv6_txoptions));
1091 		opt->tot_len = sizeof(*opt);
1092 
1093 		err = datagram_send_ctl(sock_net(sk), msg, &fl6, opt, &hlimit,
1094 					&tclass, &dontfrag);
1095 		if (err < 0) {
1096 			fl6_sock_release(flowlabel);
1097 			return err;
1098 		}
1099 		if ((fl6.flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
1100 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
1101 			if (flowlabel == NULL)
1102 				return -EINVAL;
1103 		}
1104 		if (!(opt->opt_nflen|opt->opt_flen))
1105 			opt = NULL;
1106 		connected = 0;
1107 	}
1108 	if (opt == NULL)
1109 		opt = np->opt;
1110 	if (flowlabel)
1111 		opt = fl6_merge_options(&opt_space, flowlabel, opt);
1112 	opt = ipv6_fixup_options(&opt_space, opt);
1113 
1114 	fl6.flowi6_proto = sk->sk_protocol;
1115 	if (!ipv6_addr_any(daddr))
1116 		ipv6_addr_copy(&fl6.daddr, daddr);
1117 	else
1118 		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
1119 	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
1120 		ipv6_addr_copy(&fl6.saddr, &np->saddr);
1121 	fl6.fl6_sport = inet->inet_sport;
1122 
1123 	final_p = fl6_update_dst(&fl6, opt, &final);
1124 	if (final_p)
1125 		connected = 0;
1126 
1127 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
1128 		fl6.flowi6_oif = np->mcast_oif;
1129 		connected = 0;
1130 	}
1131 
1132 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
1133 
1134 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, final_p, true);
1135 	if (IS_ERR(dst)) {
1136 		err = PTR_ERR(dst);
1137 		dst = NULL;
1138 		goto out;
1139 	}
1140 
1141 	if (hlimit < 0) {
1142 		if (ipv6_addr_is_multicast(&fl6.daddr))
1143 			hlimit = np->mcast_hops;
1144 		else
1145 			hlimit = np->hop_limit;
1146 		if (hlimit < 0)
1147 			hlimit = ip6_dst_hoplimit(dst);
1148 	}
1149 
1150 	if (tclass < 0)
1151 		tclass = np->tclass;
1152 
1153 	if (dontfrag < 0)
1154 		dontfrag = np->dontfrag;
1155 
1156 	if (msg->msg_flags&MSG_CONFIRM)
1157 		goto do_confirm;
1158 back_from_confirm:
1159 
1160 	lock_sock(sk);
1161 	if (unlikely(up->pending)) {
1162 		/* The socket is already corked while preparing it. */
1163 		/* ... which is an evident application bug. --ANK */
1164 		release_sock(sk);
1165 
1166 		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
1167 		err = -EINVAL;
1168 		goto out;
1169 	}
1170 
1171 	up->pending = AF_INET6;
1172 
1173 do_append_data:
1174 	up->len += ulen;
1175 	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
1176 	err = ip6_append_data(sk, getfrag, msg->msg_iov, ulen,
1177 		sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
1178 		(struct rt6_info*)dst,
1179 		corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
1180 	if (err)
1181 		udp_v6_flush_pending_frames(sk);
1182 	else if (!corkreq)
1183 		err = udp_v6_push_pending_frames(sk);
1184 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1185 		up->pending = 0;
1186 
1187 	if (dst) {
1188 		if (connected) {
1189 			ip6_dst_store(sk, dst,
1190 				      ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
1191 				      &np->daddr : NULL,
1192 #ifdef CONFIG_IPV6_SUBTREES
1193 				      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
1194 				      &np->saddr :
1195 #endif
1196 				      NULL);
1197 		} else {
1198 			dst_release(dst);
1199 		}
1200 		dst = NULL;
1201 	}
1202 
1203 	if (err > 0)
1204 		err = np->recverr ? net_xmit_errno(err) : 0;
1205 	release_sock(sk);
1206 out:
1207 	dst_release(dst);
1208 	fl6_sock_release(flowlabel);
1209 	if (!err)
1210 		return len;
1211 	/*
1212 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1213 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1214 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1215 	 * things).  We could add another new stat but at least for now that
1216 	 * seems like overkill.
1217 	 */
1218 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1219 		UDP6_INC_STATS_USER(sock_net(sk),
1220 				UDP_MIB_SNDBUFERRORS, is_udplite);
1221 	}
1222 	return err;
1223 
1224 do_confirm:
1225 	dst_confirm(dst);
1226 	if (!(msg->msg_flags&MSG_PROBE) || len)
1227 		goto back_from_confirm;
1228 	err = 0;
1229 	goto out;
1230 }
1231 
1232 void udpv6_destroy_sock(struct sock *sk)
1233 {
1234 	lock_sock(sk);
1235 	udp_v6_flush_pending_frames(sk);
1236 	release_sock(sk);
1237 
1238 	inet6_destroy_sock(sk);
1239 }
1240 
1241 /*
1242  *	Socket option code for UDP
1243  */
1244 int udpv6_setsockopt(struct sock *sk, int level, int optname,
1245 		     char __user *optval, unsigned int optlen)
1246 {
1247 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1248 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1249 					  udp_v6_push_pending_frames);
1250 	return ipv6_setsockopt(sk, level, optname, optval, optlen);
1251 }
1252 
1253 #ifdef CONFIG_COMPAT
1254 int compat_udpv6_setsockopt(struct sock *sk, int level, int optname,
1255 			    char __user *optval, unsigned int optlen)
1256 {
1257 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1258 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1259 					  udp_v6_push_pending_frames);
1260 	return compat_ipv6_setsockopt(sk, level, optname, optval, optlen);
1261 }
1262 #endif
1263 
1264 int udpv6_getsockopt(struct sock *sk, int level, int optname,
1265 		     char __user *optval, int __user *optlen)
1266 {
1267 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1268 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1269 	return ipv6_getsockopt(sk, level, optname, optval, optlen);
1270 }
1271 
1272 #ifdef CONFIG_COMPAT
1273 int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
1274 			    char __user *optval, int __user *optlen)
1275 {
1276 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1277 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1278 	return compat_ipv6_getsockopt(sk, level, optname, optval, optlen);
1279 }
1280 #endif
1281 
1282 static int udp6_ufo_send_check(struct sk_buff *skb)
1283 {
1284 	const struct ipv6hdr *ipv6h;
1285 	struct udphdr *uh;
1286 
1287 	if (!pskb_may_pull(skb, sizeof(*uh)))
1288 		return -EINVAL;
1289 
1290 	ipv6h = ipv6_hdr(skb);
1291 	uh = udp_hdr(skb);
1292 
1293 	uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
1294 				     IPPROTO_UDP, 0);
1295 	skb->csum_start = skb_transport_header(skb) - skb->head;
1296 	skb->csum_offset = offsetof(struct udphdr, check);
1297 	skb->ip_summed = CHECKSUM_PARTIAL;
1298 	return 0;
1299 }
1300 
1301 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, u32 features)
1302 {
1303 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1304 	unsigned int mss;
1305 	unsigned int unfrag_ip6hlen, unfrag_len;
1306 	struct frag_hdr *fptr;
1307 	u8 *mac_start, *prevhdr;
1308 	u8 nexthdr;
1309 	u8 frag_hdr_sz = sizeof(struct frag_hdr);
1310 	int offset;
1311 	__wsum csum;
1312 
1313 	mss = skb_shinfo(skb)->gso_size;
1314 	if (unlikely(skb->len <= mss))
1315 		goto out;
1316 
1317 	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
1318 		/* Packet is from an untrusted source, reset gso_segs. */
1319 		int type = skb_shinfo(skb)->gso_type;
1320 
1321 		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
1322 			     !(type & (SKB_GSO_UDP))))
1323 			goto out;
1324 
1325 		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
1326 
1327 		segs = NULL;
1328 		goto out;
1329 	}
1330 
1331 	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
1332 	 * do checksum of UDP packets sent as multiple IP fragments.
1333 	 */
1334 	offset = skb_checksum_start_offset(skb);
1335 	csum = skb_checksum(skb, offset, skb->len- offset, 0);
1336 	offset += skb->csum_offset;
1337 	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
1338 	skb->ip_summed = CHECKSUM_NONE;
1339 
1340 	/* Check if there is enough headroom to insert fragment header. */
1341 	if ((skb_mac_header(skb) < skb->head + frag_hdr_sz) &&
1342 	    pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
1343 		goto out;
1344 
1345 	/* Find the unfragmentable header and shift it left by frag_hdr_sz
1346 	 * bytes to insert fragment header.
1347 	 */
1348 	unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
1349 	nexthdr = *prevhdr;
1350 	*prevhdr = NEXTHDR_FRAGMENT;
1351 	unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
1352 		     unfrag_ip6hlen;
1353 	mac_start = skb_mac_header(skb);
1354 	memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
1355 
1356 	skb->mac_header -= frag_hdr_sz;
1357 	skb->network_header -= frag_hdr_sz;
1358 
1359 	fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
1360 	fptr->nexthdr = nexthdr;
1361 	fptr->reserved = 0;
1362 	ipv6_select_ident(fptr);
1363 
1364 	/* Fragment the skb. ipv6 header and the remaining fields of the
1365 	 * fragment header are updated in ipv6_gso_segment()
1366 	 */
1367 	segs = skb_segment(skb, features);
1368 
1369 out:
1370 	return segs;
1371 }
1372 
1373 static const struct inet6_protocol udpv6_protocol = {
1374 	.handler	=	udpv6_rcv,
1375 	.err_handler	=	udpv6_err,
1376 	.gso_send_check =	udp6_ufo_send_check,
1377 	.gso_segment	=	udp6_ufo_fragment,
1378 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
1379 };
1380 
1381 /* ------------------------------------------------------------------------ */
1382 #ifdef CONFIG_PROC_FS
1383 
1384 static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket)
1385 {
1386 	struct inet_sock *inet = inet_sk(sp);
1387 	struct ipv6_pinfo *np = inet6_sk(sp);
1388 	const struct in6_addr *dest, *src;
1389 	__u16 destp, srcp;
1390 
1391 	dest  = &np->daddr;
1392 	src   = &np->rcv_saddr;
1393 	destp = ntohs(inet->inet_dport);
1394 	srcp  = ntohs(inet->inet_sport);
1395 	seq_printf(seq,
1396 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1397 		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
1398 		   bucket,
1399 		   src->s6_addr32[0], src->s6_addr32[1],
1400 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
1401 		   dest->s6_addr32[0], dest->s6_addr32[1],
1402 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
1403 		   sp->sk_state,
1404 		   sk_wmem_alloc_get(sp),
1405 		   sk_rmem_alloc_get(sp),
1406 		   0, 0L, 0,
1407 		   sock_i_uid(sp), 0,
1408 		   sock_i_ino(sp),
1409 		   atomic_read(&sp->sk_refcnt), sp,
1410 		   atomic_read(&sp->sk_drops));
1411 }
1412 
1413 int udp6_seq_show(struct seq_file *seq, void *v)
1414 {
1415 	if (v == SEQ_START_TOKEN)
1416 		seq_printf(seq,
1417 			   "  sl  "
1418 			   "local_address                         "
1419 			   "remote_address                        "
1420 			   "st tx_queue rx_queue tr tm->when retrnsmt"
1421 			   "   uid  timeout inode ref pointer drops\n");
1422 	else
1423 		udp6_sock_seq_show(seq, v, ((struct udp_iter_state *)seq->private)->bucket);
1424 	return 0;
1425 }
1426 
1427 static struct udp_seq_afinfo udp6_seq_afinfo = {
1428 	.name		= "udp6",
1429 	.family		= AF_INET6,
1430 	.udp_table	= &udp_table,
1431 	.seq_fops	= {
1432 		.owner	=	THIS_MODULE,
1433 	},
1434 	.seq_ops	= {
1435 		.show		= udp6_seq_show,
1436 	},
1437 };
1438 
1439 int __net_init udp6_proc_init(struct net *net)
1440 {
1441 	return udp_proc_register(net, &udp6_seq_afinfo);
1442 }
1443 
1444 void udp6_proc_exit(struct net *net) {
1445 	udp_proc_unregister(net, &udp6_seq_afinfo);
1446 }
1447 #endif /* CONFIG_PROC_FS */
1448 
1449 /* ------------------------------------------------------------------------ */
1450 
1451 struct proto udpv6_prot = {
1452 	.name		   = "UDPv6",
1453 	.owner		   = THIS_MODULE,
1454 	.close		   = udp_lib_close,
1455 	.connect	   = ip6_datagram_connect,
1456 	.disconnect	   = udp_disconnect,
1457 	.ioctl		   = udp_ioctl,
1458 	.destroy	   = udpv6_destroy_sock,
1459 	.setsockopt	   = udpv6_setsockopt,
1460 	.getsockopt	   = udpv6_getsockopt,
1461 	.sendmsg	   = udpv6_sendmsg,
1462 	.recvmsg	   = udpv6_recvmsg,
1463 	.backlog_rcv	   = udpv6_queue_rcv_skb,
1464 	.hash		   = udp_lib_hash,
1465 	.unhash		   = udp_lib_unhash,
1466 	.rehash		   = udp_v6_rehash,
1467 	.get_port	   = udp_v6_get_port,
1468 	.memory_allocated  = &udp_memory_allocated,
1469 	.sysctl_mem	   = sysctl_udp_mem,
1470 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1471 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1472 	.obj_size	   = sizeof(struct udp6_sock),
1473 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1474 	.h.udp_table	   = &udp_table,
1475 #ifdef CONFIG_COMPAT
1476 	.compat_setsockopt = compat_udpv6_setsockopt,
1477 	.compat_getsockopt = compat_udpv6_getsockopt,
1478 #endif
1479 	.clear_sk	   = sk_prot_clear_portaddr_nulls,
1480 };
1481 
1482 static struct inet_protosw udpv6_protosw = {
1483 	.type =      SOCK_DGRAM,
1484 	.protocol =  IPPROTO_UDP,
1485 	.prot =      &udpv6_prot,
1486 	.ops =       &inet6_dgram_ops,
1487 	.no_check =  UDP_CSUM_DEFAULT,
1488 	.flags =     INET_PROTOSW_PERMANENT,
1489 };
1490 
1491 
1492 int __init udpv6_init(void)
1493 {
1494 	int ret;
1495 
1496 	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
1497 	if (ret)
1498 		goto out;
1499 
1500 	ret = inet6_register_protosw(&udpv6_protosw);
1501 	if (ret)
1502 		goto out_udpv6_protocol;
1503 out:
1504 	return ret;
1505 
1506 out_udpv6_protocol:
1507 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1508 	goto out;
1509 }
1510 
1511 void udpv6_exit(void)
1512 {
1513 	inet6_unregister_protosw(&udpv6_protosw);
1514 	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
1515 }
1516