xref: /linux/net/ipv6/ip6_output.c (revision 6e8331ac6973435b1e7604c30f2ad394035b46e1)
1 /*
2  *	IPv6 output functions
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	$Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $
9  *
10  *	Based on linux/net/ipv4/ip_output.c
11  *
12  *	This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  *
17  *	Changes:
18  *	A.N.Kuznetsov	:	airthmetics in fragmentation.
19  *				extension headers are implemented.
20  *				route changes now work.
21  *				ip6_forward does not confuse sniffers.
22  *				etc.
23  *
24  *      H. von Brand    :       Added missing #include <linux/string.h>
25  *	Imran Patel	: 	frag id should be in NBO
26  *      Kazunori MIYAZAWA @USAGI
27  *			:       add ip6_append_data and related functions
28  *				for datagram xmit
29  */
30 
31 #include <linux/errno.h>
32 #include <linux/types.h>
33 #include <linux/string.h>
34 #include <linux/socket.h>
35 #include <linux/net.h>
36 #include <linux/netdevice.h>
37 #include <linux/if_arp.h>
38 #include <linux/in6.h>
39 #include <linux/tcp.h>
40 #include <linux/route.h>
41 #include <linux/module.h>
42 
43 #include <linux/netfilter.h>
44 #include <linux/netfilter_ipv6.h>
45 
46 #include <net/sock.h>
47 #include <net/snmp.h>
48 
49 #include <net/ipv6.h>
50 #include <net/ndisc.h>
51 #include <net/protocol.h>
52 #include <net/ip6_route.h>
53 #include <net/addrconf.h>
54 #include <net/rawv6.h>
55 #include <net/icmp.h>
56 #include <net/xfrm.h>
57 #include <net/checksum.h>
58 
59 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
60 
61 static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr)
62 {
63 	static u32 ipv6_fragmentation_id = 1;
64 	static DEFINE_SPINLOCK(ip6_id_lock);
65 
66 	spin_lock_bh(&ip6_id_lock);
67 	fhdr->identification = htonl(ipv6_fragmentation_id);
68 	if (++ipv6_fragmentation_id == 0)
69 		ipv6_fragmentation_id = 1;
70 	spin_unlock_bh(&ip6_id_lock);
71 }
72 
73 static inline int ip6_output_finish(struct sk_buff *skb)
74 {
75 
76 	struct dst_entry *dst = skb->dst;
77 	struct hh_cache *hh = dst->hh;
78 
79 	if (hh) {
80 		int hh_alen;
81 
82 		read_lock_bh(&hh->hh_lock);
83 		hh_alen = HH_DATA_ALIGN(hh->hh_len);
84 		memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
85 		read_unlock_bh(&hh->hh_lock);
86 	        skb_push(skb, hh->hh_len);
87 		return hh->hh_output(skb);
88 	} else if (dst->neighbour)
89 		return dst->neighbour->output(skb);
90 
91 	IP6_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
92 	kfree_skb(skb);
93 	return -EINVAL;
94 
95 }
96 
97 /* dev_loopback_xmit for use with netfilter. */
98 static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
99 {
100 	newskb->mac.raw = newskb->data;
101 	__skb_pull(newskb, newskb->nh.raw - newskb->data);
102 	newskb->pkt_type = PACKET_LOOPBACK;
103 	newskb->ip_summed = CHECKSUM_UNNECESSARY;
104 	BUG_TRAP(newskb->dst);
105 
106 	netif_rx(newskb);
107 	return 0;
108 }
109 
110 
111 static int ip6_output2(struct sk_buff *skb)
112 {
113 	struct dst_entry *dst = skb->dst;
114 	struct net_device *dev = dst->dev;
115 
116 	skb->protocol = htons(ETH_P_IPV6);
117 	skb->dev = dev;
118 
119 	if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr)) {
120 		struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;
121 
122 		if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
123 		    ipv6_chk_mcast_addr(dev, &skb->nh.ipv6h->daddr,
124 				&skb->nh.ipv6h->saddr)) {
125 			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
126 
127 			/* Do not check for IFF_ALLMULTI; multicast routing
128 			   is not supported in any case.
129 			 */
130 			if (newskb)
131 				NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL,
132 					newskb->dev,
133 					ip6_dev_loopback_xmit);
134 
135 			if (skb->nh.ipv6h->hop_limit == 0) {
136 				IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
137 				kfree_skb(skb);
138 				return 0;
139 			}
140 		}
141 
142 		IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
143 	}
144 
145 	return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish);
146 }
147 
148 int ip6_output(struct sk_buff *skb)
149 {
150 	if ((skb->len > dst_mtu(skb->dst) && !skb_is_gso(skb)) ||
151 				dst_allfrag(skb->dst))
152 		return ip6_fragment(skb, ip6_output2);
153 	else
154 		return ip6_output2(skb);
155 }
156 
157 /*
158  *	xmit an sk_buff (used by TCP)
159  */
160 
161 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
162 	     struct ipv6_txoptions *opt, int ipfragok)
163 {
164 	struct ipv6_pinfo *np = inet6_sk(sk);
165 	struct in6_addr *first_hop = &fl->fl6_dst;
166 	struct dst_entry *dst = skb->dst;
167 	struct ipv6hdr *hdr;
168 	u8  proto = fl->proto;
169 	int seg_len = skb->len;
170 	int hlimit, tclass;
171 	u32 mtu;
172 
173 	if (opt) {
174 		int head_room;
175 
176 		/* First: exthdrs may take lots of space (~8K for now)
177 		   MAX_HEADER is not enough.
178 		 */
179 		head_room = opt->opt_nflen + opt->opt_flen;
180 		seg_len += head_room;
181 		head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
182 
183 		if (skb_headroom(skb) < head_room) {
184 			struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
185 			kfree_skb(skb);
186 			skb = skb2;
187 			if (skb == NULL) {
188 				IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
189 				return -ENOBUFS;
190 			}
191 			if (sk)
192 				skb_set_owner_w(skb, sk);
193 		}
194 		if (opt->opt_flen)
195 			ipv6_push_frag_opts(skb, opt, &proto);
196 		if (opt->opt_nflen)
197 			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
198 	}
199 
200 	hdr = skb->nh.ipv6h = (struct ipv6hdr*)skb_push(skb, sizeof(struct ipv6hdr));
201 
202 	/*
203 	 *	Fill in the IPv6 header
204 	 */
205 
206 	hlimit = -1;
207 	if (np)
208 		hlimit = np->hop_limit;
209 	if (hlimit < 0)
210 		hlimit = dst_metric(dst, RTAX_HOPLIMIT);
211 	if (hlimit < 0)
212 		hlimit = ipv6_get_hoplimit(dst->dev);
213 
214 	tclass = -1;
215 	if (np)
216 		tclass = np->tclass;
217 	if (tclass < 0)
218 		tclass = 0;
219 
220 	*(u32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;
221 
222 	hdr->payload_len = htons(seg_len);
223 	hdr->nexthdr = proto;
224 	hdr->hop_limit = hlimit;
225 
226 	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
227 	ipv6_addr_copy(&hdr->daddr, first_hop);
228 
229 	skb->priority = sk->sk_priority;
230 
231 	mtu = dst_mtu(dst);
232 	if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
233 		IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
234 		return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
235 				dst_output);
236 	}
237 
238 	if (net_ratelimit())
239 		printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
240 	skb->dev = dst->dev;
241 	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
242 	IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
243 	kfree_skb(skb);
244 	return -EMSGSIZE;
245 }
246 
247 /*
248  *	To avoid extra problems ND packets are send through this
249  *	routine. It's code duplication but I really want to avoid
250  *	extra checks since ipv6_build_header is used by TCP (which
251  *	is for us performance critical)
252  */
253 
254 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
255 	       struct in6_addr *saddr, struct in6_addr *daddr,
256 	       int proto, int len)
257 {
258 	struct ipv6_pinfo *np = inet6_sk(sk);
259 	struct ipv6hdr *hdr;
260 	int totlen;
261 
262 	skb->protocol = htons(ETH_P_IPV6);
263 	skb->dev = dev;
264 
265 	totlen = len + sizeof(struct ipv6hdr);
266 
267 	hdr = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr));
268 	skb->nh.ipv6h = hdr;
269 
270 	*(u32*)hdr = htonl(0x60000000);
271 
272 	hdr->payload_len = htons(len);
273 	hdr->nexthdr = proto;
274 	hdr->hop_limit = np->hop_limit;
275 
276 	ipv6_addr_copy(&hdr->saddr, saddr);
277 	ipv6_addr_copy(&hdr->daddr, daddr);
278 
279 	return 0;
280 }
281 
282 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
283 {
284 	struct ip6_ra_chain *ra;
285 	struct sock *last = NULL;
286 
287 	read_lock(&ip6_ra_lock);
288 	for (ra = ip6_ra_chain; ra; ra = ra->next) {
289 		struct sock *sk = ra->sk;
290 		if (sk && ra->sel == sel &&
291 		    (!sk->sk_bound_dev_if ||
292 		     sk->sk_bound_dev_if == skb->dev->ifindex)) {
293 			if (last) {
294 				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
295 				if (skb2)
296 					rawv6_rcv(last, skb2);
297 			}
298 			last = sk;
299 		}
300 	}
301 
302 	if (last) {
303 		rawv6_rcv(last, skb);
304 		read_unlock(&ip6_ra_lock);
305 		return 1;
306 	}
307 	read_unlock(&ip6_ra_lock);
308 	return 0;
309 }
310 
311 static inline int ip6_forward_finish(struct sk_buff *skb)
312 {
313 	return dst_output(skb);
314 }
315 
316 int ip6_forward(struct sk_buff *skb)
317 {
318 	struct dst_entry *dst = skb->dst;
319 	struct ipv6hdr *hdr = skb->nh.ipv6h;
320 	struct inet6_skb_parm *opt = IP6CB(skb);
321 
322 	if (ipv6_devconf.forwarding == 0)
323 		goto error;
324 
325 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
326 		IP6_INC_STATS(IPSTATS_MIB_INDISCARDS);
327 		goto drop;
328 	}
329 
330 	skb->ip_summed = CHECKSUM_NONE;
331 
332 	/*
333 	 *	We DO NOT make any processing on
334 	 *	RA packets, pushing them to user level AS IS
335 	 *	without ane WARRANTY that application will be able
336 	 *	to interpret them. The reason is that we
337 	 *	cannot make anything clever here.
338 	 *
339 	 *	We are not end-node, so that if packet contains
340 	 *	AH/ESP, we cannot make anything.
341 	 *	Defragmentation also would be mistake, RA packets
342 	 *	cannot be fragmented, because there is no warranty
343 	 *	that different fragments will go along one path. --ANK
344 	 */
345 	if (opt->ra) {
346 		u8 *ptr = skb->nh.raw + opt->ra;
347 		if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
348 			return 0;
349 	}
350 
351 	/*
352 	 *	check and decrement ttl
353 	 */
354 	if (hdr->hop_limit <= 1) {
355 		/* Force OUTPUT device used as source address */
356 		skb->dev = dst->dev;
357 		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
358 			    0, skb->dev);
359 		IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
360 
361 		kfree_skb(skb);
362 		return -ETIMEDOUT;
363 	}
364 
365 	if (!xfrm6_route_forward(skb)) {
366 		IP6_INC_STATS(IPSTATS_MIB_INDISCARDS);
367 		goto drop;
368 	}
369 	dst = skb->dst;
370 
371 	/* IPv6 specs say nothing about it, but it is clear that we cannot
372 	   send redirects to source routed frames.
373 	 */
374 	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
375 		struct in6_addr *target = NULL;
376 		struct rt6_info *rt;
377 		struct neighbour *n = dst->neighbour;
378 
379 		/*
380 		 *	incoming and outgoing devices are the same
381 		 *	send a redirect.
382 		 */
383 
384 		rt = (struct rt6_info *) dst;
385 		if ((rt->rt6i_flags & RTF_GATEWAY))
386 			target = (struct in6_addr*)&n->primary_key;
387 		else
388 			target = &hdr->daddr;
389 
390 		/* Limit redirects both by destination (here)
391 		   and by source (inside ndisc_send_redirect)
392 		 */
393 		if (xrlim_allow(dst, 1*HZ))
394 			ndisc_send_redirect(skb, n, target);
395 	} else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK
396 						|IPV6_ADDR_LINKLOCAL)) {
397 		/* This check is security critical. */
398 		goto error;
399 	}
400 
401 	if (skb->len > dst_mtu(dst)) {
402 		/* Again, force OUTPUT device used as source address */
403 		skb->dev = dst->dev;
404 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
405 		IP6_INC_STATS_BH(IPSTATS_MIB_INTOOBIGERRORS);
406 		IP6_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS);
407 		kfree_skb(skb);
408 		return -EMSGSIZE;
409 	}
410 
411 	if (skb_cow(skb, dst->dev->hard_header_len)) {
412 		IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
413 		goto drop;
414 	}
415 
416 	hdr = skb->nh.ipv6h;
417 
418 	/* Mangling hops number delayed to point after skb COW */
419 
420 	hdr->hop_limit--;
421 
422 	IP6_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS);
423 	return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish);
424 
425 error:
426 	IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
427 drop:
428 	kfree_skb(skb);
429 	return -EINVAL;
430 }
431 
432 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
433 {
434 	to->pkt_type = from->pkt_type;
435 	to->priority = from->priority;
436 	to->protocol = from->protocol;
437 	dst_release(to->dst);
438 	to->dst = dst_clone(from->dst);
439 	to->dev = from->dev;
440 
441 #ifdef CONFIG_NET_SCHED
442 	to->tc_index = from->tc_index;
443 #endif
444 #ifdef CONFIG_NETFILTER
445 	to->nfmark = from->nfmark;
446 	/* Connection association is same as pre-frag packet */
447 	nf_conntrack_put(to->nfct);
448 	to->nfct = from->nfct;
449 	nf_conntrack_get(to->nfct);
450 	to->nfctinfo = from->nfctinfo;
451 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
452 	nf_conntrack_put_reasm(to->nfct_reasm);
453 	to->nfct_reasm = from->nfct_reasm;
454 	nf_conntrack_get_reasm(to->nfct_reasm);
455 #endif
456 #ifdef CONFIG_BRIDGE_NETFILTER
457 	nf_bridge_put(to->nf_bridge);
458 	to->nf_bridge = from->nf_bridge;
459 	nf_bridge_get(to->nf_bridge);
460 #endif
461 #endif
462 	skb_copy_secmark(to, from);
463 }
464 
465 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
466 {
467 	u16 offset = sizeof(struct ipv6hdr);
468 	struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
469 	unsigned int packet_len = skb->tail - skb->nh.raw;
470 	int found_rhdr = 0;
471 	*nexthdr = &skb->nh.ipv6h->nexthdr;
472 
473 	while (offset + 1 <= packet_len) {
474 
475 		switch (**nexthdr) {
476 
477 		case NEXTHDR_HOP:
478 		case NEXTHDR_ROUTING:
479 		case NEXTHDR_DEST:
480 			if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1;
481 			if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset;
482 			offset += ipv6_optlen(exthdr);
483 			*nexthdr = &exthdr->nexthdr;
484 			exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
485 			break;
486 		default :
487 			return offset;
488 		}
489 	}
490 
491 	return offset;
492 }
493 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
494 
495 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
496 {
497 	struct net_device *dev;
498 	struct sk_buff *frag;
499 	struct rt6_info *rt = (struct rt6_info*)skb->dst;
500 	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
501 	struct ipv6hdr *tmp_hdr;
502 	struct frag_hdr *fh;
503 	unsigned int mtu, hlen, left, len;
504 	u32 frag_id = 0;
505 	int ptr, offset = 0, err=0;
506 	u8 *prevhdr, nexthdr = 0;
507 
508 	dev = rt->u.dst.dev;
509 	hlen = ip6_find_1stfragopt(skb, &prevhdr);
510 	nexthdr = *prevhdr;
511 
512 	mtu = dst_mtu(&rt->u.dst);
513 	if (np && np->frag_size < mtu) {
514 		if (np->frag_size)
515 			mtu = np->frag_size;
516 	}
517 	mtu -= hlen + sizeof(struct frag_hdr);
518 
519 	if (skb_shinfo(skb)->frag_list) {
520 		int first_len = skb_pagelen(skb);
521 
522 		if (first_len - hlen > mtu ||
523 		    ((first_len - hlen) & 7) ||
524 		    skb_cloned(skb))
525 			goto slow_path;
526 
527 		for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
528 			/* Correct geometry. */
529 			if (frag->len > mtu ||
530 			    ((frag->len & 7) && frag->next) ||
531 			    skb_headroom(frag) < hlen)
532 			    goto slow_path;
533 
534 			/* Partially cloned skb? */
535 			if (skb_shared(frag))
536 				goto slow_path;
537 
538 			BUG_ON(frag->sk);
539 			if (skb->sk) {
540 				sock_hold(skb->sk);
541 				frag->sk = skb->sk;
542 				frag->destructor = sock_wfree;
543 				skb->truesize -= frag->truesize;
544 			}
545 		}
546 
547 		err = 0;
548 		offset = 0;
549 		frag = skb_shinfo(skb)->frag_list;
550 		skb_shinfo(skb)->frag_list = NULL;
551 		/* BUILD HEADER */
552 
553 		tmp_hdr = kmalloc(hlen, GFP_ATOMIC);
554 		if (!tmp_hdr) {
555 			IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
556 			return -ENOMEM;
557 		}
558 
559 		*prevhdr = NEXTHDR_FRAGMENT;
560 		memcpy(tmp_hdr, skb->nh.raw, hlen);
561 		__skb_pull(skb, hlen);
562 		fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
563 		skb->nh.raw = __skb_push(skb, hlen);
564 		memcpy(skb->nh.raw, tmp_hdr, hlen);
565 
566 		ipv6_select_ident(skb, fh);
567 		fh->nexthdr = nexthdr;
568 		fh->reserved = 0;
569 		fh->frag_off = htons(IP6_MF);
570 		frag_id = fh->identification;
571 
572 		first_len = skb_pagelen(skb);
573 		skb->data_len = first_len - skb_headlen(skb);
574 		skb->len = first_len;
575 		skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr));
576 
577 
578 		for (;;) {
579 			/* Prepare header of the next frame,
580 			 * before previous one went down. */
581 			if (frag) {
582 				frag->ip_summed = CHECKSUM_NONE;
583 				frag->h.raw = frag->data;
584 				fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
585 				frag->nh.raw = __skb_push(frag, hlen);
586 				memcpy(frag->nh.raw, tmp_hdr, hlen);
587 				offset += skb->len - hlen - sizeof(struct frag_hdr);
588 				fh->nexthdr = nexthdr;
589 				fh->reserved = 0;
590 				fh->frag_off = htons(offset);
591 				if (frag->next != NULL)
592 					fh->frag_off |= htons(IP6_MF);
593 				fh->identification = frag_id;
594 				frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
595 				ip6_copy_metadata(frag, skb);
596 			}
597 
598 			err = output(skb);
599 			if(!err)
600 				IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES);
601 
602 			if (err || !frag)
603 				break;
604 
605 			skb = frag;
606 			frag = skb->next;
607 			skb->next = NULL;
608 		}
609 
610 		kfree(tmp_hdr);
611 
612 		if (err == 0) {
613 			IP6_INC_STATS(IPSTATS_MIB_FRAGOKS);
614 			return 0;
615 		}
616 
617 		while (frag) {
618 			skb = frag->next;
619 			kfree_skb(frag);
620 			frag = skb;
621 		}
622 
623 		IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
624 		return err;
625 	}
626 
627 slow_path:
628 	left = skb->len - hlen;		/* Space per frame */
629 	ptr = hlen;			/* Where to start from */
630 
631 	/*
632 	 *	Fragment the datagram.
633 	 */
634 
635 	*prevhdr = NEXTHDR_FRAGMENT;
636 
637 	/*
638 	 *	Keep copying data until we run out.
639 	 */
640 	while(left > 0)	{
641 		len = left;
642 		/* IF: it doesn't fit, use 'mtu' - the data space left */
643 		if (len > mtu)
644 			len = mtu;
645 		/* IF: we are not sending upto and including the packet end
646 		   then align the next start on an eight byte boundary */
647 		if (len < left)	{
648 			len &= ~7;
649 		}
650 		/*
651 		 *	Allocate buffer.
652 		 */
653 
654 		if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
655 			NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
656 			IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
657 			err = -ENOMEM;
658 			goto fail;
659 		}
660 
661 		/*
662 		 *	Set up data on packet
663 		 */
664 
665 		ip6_copy_metadata(frag, skb);
666 		skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
667 		skb_put(frag, len + hlen + sizeof(struct frag_hdr));
668 		frag->nh.raw = frag->data;
669 		fh = (struct frag_hdr*)(frag->data + hlen);
670 		frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr);
671 
672 		/*
673 		 *	Charge the memory for the fragment to any owner
674 		 *	it might possess
675 		 */
676 		if (skb->sk)
677 			skb_set_owner_w(frag, skb->sk);
678 
679 		/*
680 		 *	Copy the packet header into the new buffer.
681 		 */
682 		memcpy(frag->nh.raw, skb->data, hlen);
683 
684 		/*
685 		 *	Build fragment header.
686 		 */
687 		fh->nexthdr = nexthdr;
688 		fh->reserved = 0;
689 		if (!frag_id) {
690 			ipv6_select_ident(skb, fh);
691 			frag_id = fh->identification;
692 		} else
693 			fh->identification = frag_id;
694 
695 		/*
696 		 *	Copy a block of the IP datagram.
697 		 */
698 		if (skb_copy_bits(skb, ptr, frag->h.raw, len))
699 			BUG();
700 		left -= len;
701 
702 		fh->frag_off = htons(offset);
703 		if (left > 0)
704 			fh->frag_off |= htons(IP6_MF);
705 		frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
706 
707 		ptr += len;
708 		offset += len;
709 
710 		/*
711 		 *	Put this fragment into the sending queue.
712 		 */
713 		err = output(frag);
714 		if (err)
715 			goto fail;
716 
717 		IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES);
718 	}
719 	kfree_skb(skb);
720 	IP6_INC_STATS(IPSTATS_MIB_FRAGOKS);
721 	return err;
722 
723 fail:
724 	kfree_skb(skb);
725 	IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
726 	return err;
727 }
728 
729 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
730 					  struct dst_entry *dst,
731 					  struct flowi *fl)
732 {
733 	struct ipv6_pinfo *np = inet6_sk(sk);
734 	struct rt6_info *rt = (struct rt6_info *)dst;
735 
736 	if (!dst)
737 		goto out;
738 
739 	/* Yes, checking route validity in not connected
740 	 * case is not very simple. Take into account,
741 	 * that we do not support routing by source, TOS,
742 	 * and MSG_DONTROUTE 		--ANK (980726)
743 	 *
744 	 * 1. If route was host route, check that
745 	 *    cached destination is current.
746 	 *    If it is network route, we still may
747 	 *    check its validity using saved pointer
748 	 *    to the last used address: daddr_cache.
749 	 *    We do not want to save whole address now,
750 	 *    (because main consumer of this service
751 	 *    is tcp, which has not this problem),
752 	 *    so that the last trick works only on connected
753 	 *    sockets.
754 	 * 2. oif also should be the same.
755 	 */
756 	if (((rt->rt6i_dst.plen != 128 ||
757 	      !ipv6_addr_equal(&fl->fl6_dst, &rt->rt6i_dst.addr))
758 	     && (np->daddr_cache == NULL ||
759 		 !ipv6_addr_equal(&fl->fl6_dst, np->daddr_cache)))
760 	    || (fl->oif && fl->oif != dst->dev->ifindex)) {
761 		dst_release(dst);
762 		dst = NULL;
763 	}
764 
765 out:
766 	return dst;
767 }
768 
769 static int ip6_dst_lookup_tail(struct sock *sk,
770 			       struct dst_entry **dst, struct flowi *fl)
771 {
772 	int err;
773 
774 	if (*dst == NULL)
775 		*dst = ip6_route_output(sk, fl);
776 
777 	if ((err = (*dst)->error))
778 		goto out_err_release;
779 
780 	if (ipv6_addr_any(&fl->fl6_src)) {
781 		err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);
782 		if (err)
783 			goto out_err_release;
784 	}
785 
786 	return 0;
787 
788 out_err_release:
789 	dst_release(*dst);
790 	*dst = NULL;
791 	return err;
792 }
793 
794 /**
795  *	ip6_dst_lookup - perform route lookup on flow
796  *	@sk: socket which provides route info
797  *	@dst: pointer to dst_entry * for result
798  *	@fl: flow to lookup
799  *
800  *	This function performs a route lookup on the given flow.
801  *
802  *	It returns zero on success, or a standard errno code on error.
803  */
804 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
805 {
806 	*dst = NULL;
807 	return ip6_dst_lookup_tail(sk, dst, fl);
808 }
809 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
810 
811 /**
812  *	ip6_sk_dst_lookup - perform socket cached route lookup on flow
813  *	@sk: socket which provides the dst cache and route info
814  *	@dst: pointer to dst_entry * for result
815  *	@fl: flow to lookup
816  *
817  *	This function performs a route lookup on the given flow with the
818  *	possibility of using the cached route in the socket if it is valid.
819  *	It will take the socket dst lock when operating on the dst cache.
820  *	As a result, this function can only be used in process context.
821  *
822  *	It returns zero on success, or a standard errno code on error.
823  */
824 int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
825 {
826 	*dst = NULL;
827 	if (sk) {
828 		*dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
829 		*dst = ip6_sk_dst_check(sk, *dst, fl);
830 	}
831 
832 	return ip6_dst_lookup_tail(sk, dst, fl);
833 }
834 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup);
835 
836 static inline int ip6_ufo_append_data(struct sock *sk,
837 			int getfrag(void *from, char *to, int offset, int len,
838 			int odd, struct sk_buff *skb),
839 			void *from, int length, int hh_len, int fragheaderlen,
840 			int transhdrlen, int mtu,unsigned int flags)
841 
842 {
843 	struct sk_buff *skb;
844 	int err;
845 
846 	/* There is support for UDP large send offload by network
847 	 * device, so create one single skb packet containing complete
848 	 * udp datagram
849 	 */
850 	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
851 		skb = sock_alloc_send_skb(sk,
852 			hh_len + fragheaderlen + transhdrlen + 20,
853 			(flags & MSG_DONTWAIT), &err);
854 		if (skb == NULL)
855 			return -ENOMEM;
856 
857 		/* reserve space for Hardware header */
858 		skb_reserve(skb, hh_len);
859 
860 		/* create space for UDP/IP header */
861 		skb_put(skb,fragheaderlen + transhdrlen);
862 
863 		/* initialize network header pointer */
864 		skb->nh.raw = skb->data;
865 
866 		/* initialize protocol header pointer */
867 		skb->h.raw = skb->data + fragheaderlen;
868 
869 		skb->ip_summed = CHECKSUM_HW;
870 		skb->csum = 0;
871 		sk->sk_sndmsg_off = 0;
872 	}
873 
874 	err = skb_append_datato_frags(sk,skb, getfrag, from,
875 				      (length - transhdrlen));
876 	if (!err) {
877 		struct frag_hdr fhdr;
878 
879 		/* specify the length of each IP datagram fragment*/
880 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen -
881 					    sizeof(struct frag_hdr);
882 		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
883 		ipv6_select_ident(skb, &fhdr);
884 		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
885 		__skb_queue_tail(&sk->sk_write_queue, skb);
886 
887 		return 0;
888 	}
889 	/* There is not enough support do UPD LSO,
890 	 * so follow normal path
891 	 */
892 	kfree_skb(skb);
893 
894 	return err;
895 }
896 
897 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
898 	int offset, int len, int odd, struct sk_buff *skb),
899 	void *from, int length, int transhdrlen,
900 	int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
901 	struct rt6_info *rt, unsigned int flags)
902 {
903 	struct inet_sock *inet = inet_sk(sk);
904 	struct ipv6_pinfo *np = inet6_sk(sk);
905 	struct sk_buff *skb;
906 	unsigned int maxfraglen, fragheaderlen;
907 	int exthdrlen;
908 	int hh_len;
909 	int mtu;
910 	int copy;
911 	int err;
912 	int offset = 0;
913 	int csummode = CHECKSUM_NONE;
914 
915 	if (flags&MSG_PROBE)
916 		return 0;
917 	if (skb_queue_empty(&sk->sk_write_queue)) {
918 		/*
919 		 * setup for corking
920 		 */
921 		if (opt) {
922 			if (np->cork.opt == NULL) {
923 				np->cork.opt = kmalloc(opt->tot_len,
924 						       sk->sk_allocation);
925 				if (unlikely(np->cork.opt == NULL))
926 					return -ENOBUFS;
927 			} else if (np->cork.opt->tot_len < opt->tot_len) {
928 				printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
929 				return -EINVAL;
930 			}
931 			memcpy(np->cork.opt, opt, opt->tot_len);
932 			inet->cork.flags |= IPCORK_OPT;
933 			/* need source address above miyazawa*/
934 		}
935 		dst_hold(&rt->u.dst);
936 		np->cork.rt = rt;
937 		inet->cork.fl = *fl;
938 		np->cork.hop_limit = hlimit;
939 		np->cork.tclass = tclass;
940 		mtu = dst_mtu(rt->u.dst.path);
941 		if (np->frag_size < mtu) {
942 			if (np->frag_size)
943 				mtu = np->frag_size;
944 		}
945 		inet->cork.fragsize = mtu;
946 		if (dst_allfrag(rt->u.dst.path))
947 			inet->cork.flags |= IPCORK_ALLFRAG;
948 		inet->cork.length = 0;
949 		sk->sk_sndmsg_page = NULL;
950 		sk->sk_sndmsg_off = 0;
951 		exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0);
952 		length += exthdrlen;
953 		transhdrlen += exthdrlen;
954 	} else {
955 		rt = np->cork.rt;
956 		fl = &inet->cork.fl;
957 		if (inet->cork.flags & IPCORK_OPT)
958 			opt = np->cork.opt;
959 		transhdrlen = 0;
960 		exthdrlen = 0;
961 		mtu = inet->cork.fragsize;
962 	}
963 
964 	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
965 
966 	fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0);
967 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
968 
969 	if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
970 		if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
971 			ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
972 			return -EMSGSIZE;
973 		}
974 	}
975 
976 	/*
977 	 * Let's try using as much space as possible.
978 	 * Use MTU if total length of the message fits into the MTU.
979 	 * Otherwise, we need to reserve fragment header and
980 	 * fragment alignment (= 8-15 octects, in total).
981 	 *
982 	 * Note that we may need to "move" the data from the tail of
983 	 * of the buffer to the new fragment when we split
984 	 * the message.
985 	 *
986 	 * FIXME: It may be fragmented into multiple chunks
987 	 *        at once if non-fragmentable extension headers
988 	 *        are too large.
989 	 * --yoshfuji
990 	 */
991 
992 	inet->cork.length += length;
993 	if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
994 	    (rt->u.dst.dev->features & NETIF_F_UFO)) {
995 
996 		err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
997 					  fragheaderlen, transhdrlen, mtu,
998 					  flags);
999 		if (err)
1000 			goto error;
1001 		return 0;
1002 	}
1003 
1004 	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1005 		goto alloc_new_skb;
1006 
1007 	while (length > 0) {
1008 		/* Check if the remaining data fits into current packet. */
1009 		copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1010 		if (copy < length)
1011 			copy = maxfraglen - skb->len;
1012 
1013 		if (copy <= 0) {
1014 			char *data;
1015 			unsigned int datalen;
1016 			unsigned int fraglen;
1017 			unsigned int fraggap;
1018 			unsigned int alloclen;
1019 			struct sk_buff *skb_prev;
1020 alloc_new_skb:
1021 			skb_prev = skb;
1022 
1023 			/* There's no room in the current skb */
1024 			if (skb_prev)
1025 				fraggap = skb_prev->len - maxfraglen;
1026 			else
1027 				fraggap = 0;
1028 
1029 			/*
1030 			 * If remaining data exceeds the mtu,
1031 			 * we know we need more fragment(s).
1032 			 */
1033 			datalen = length + fraggap;
1034 			if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1035 				datalen = maxfraglen - fragheaderlen;
1036 
1037 			fraglen = datalen + fragheaderlen;
1038 			if ((flags & MSG_MORE) &&
1039 			    !(rt->u.dst.dev->features&NETIF_F_SG))
1040 				alloclen = mtu;
1041 			else
1042 				alloclen = datalen + fragheaderlen;
1043 
1044 			/*
1045 			 * The last fragment gets additional space at tail.
1046 			 * Note: we overallocate on fragments with MSG_MODE
1047 			 * because we have no idea if we're the last one.
1048 			 */
1049 			if (datalen == length + fraggap)
1050 				alloclen += rt->u.dst.trailer_len;
1051 
1052 			/*
1053 			 * We just reserve space for fragment header.
1054 			 * Note: this may be overallocation if the message
1055 			 * (without MSG_MORE) fits into the MTU.
1056 			 */
1057 			alloclen += sizeof(struct frag_hdr);
1058 
1059 			if (transhdrlen) {
1060 				skb = sock_alloc_send_skb(sk,
1061 						alloclen + hh_len,
1062 						(flags & MSG_DONTWAIT), &err);
1063 			} else {
1064 				skb = NULL;
1065 				if (atomic_read(&sk->sk_wmem_alloc) <=
1066 				    2 * sk->sk_sndbuf)
1067 					skb = sock_wmalloc(sk,
1068 							   alloclen + hh_len, 1,
1069 							   sk->sk_allocation);
1070 				if (unlikely(skb == NULL))
1071 					err = -ENOBUFS;
1072 			}
1073 			if (skb == NULL)
1074 				goto error;
1075 			/*
1076 			 *	Fill in the control structures
1077 			 */
1078 			skb->ip_summed = csummode;
1079 			skb->csum = 0;
1080 			/* reserve for fragmentation */
1081 			skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
1082 
1083 			/*
1084 			 *	Find where to start putting bytes
1085 			 */
1086 			data = skb_put(skb, fraglen);
1087 			skb->nh.raw = data + exthdrlen;
1088 			data += fragheaderlen;
1089 			skb->h.raw = data + exthdrlen;
1090 
1091 			if (fraggap) {
1092 				skb->csum = skb_copy_and_csum_bits(
1093 					skb_prev, maxfraglen,
1094 					data + transhdrlen, fraggap, 0);
1095 				skb_prev->csum = csum_sub(skb_prev->csum,
1096 							  skb->csum);
1097 				data += fraggap;
1098 				skb_trim(skb_prev, maxfraglen);
1099 			}
1100 			copy = datalen - transhdrlen - fraggap;
1101 			if (copy < 0) {
1102 				err = -EINVAL;
1103 				kfree_skb(skb);
1104 				goto error;
1105 			} else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1106 				err = -EFAULT;
1107 				kfree_skb(skb);
1108 				goto error;
1109 			}
1110 
1111 			offset += copy;
1112 			length -= datalen - fraggap;
1113 			transhdrlen = 0;
1114 			exthdrlen = 0;
1115 			csummode = CHECKSUM_NONE;
1116 
1117 			/*
1118 			 * Put the packet on the pending queue
1119 			 */
1120 			__skb_queue_tail(&sk->sk_write_queue, skb);
1121 			continue;
1122 		}
1123 
1124 		if (copy > length)
1125 			copy = length;
1126 
1127 		if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
1128 			unsigned int off;
1129 
1130 			off = skb->len;
1131 			if (getfrag(from, skb_put(skb, copy),
1132 						offset, copy, off, skb) < 0) {
1133 				__skb_trim(skb, off);
1134 				err = -EFAULT;
1135 				goto error;
1136 			}
1137 		} else {
1138 			int i = skb_shinfo(skb)->nr_frags;
1139 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1140 			struct page *page = sk->sk_sndmsg_page;
1141 			int off = sk->sk_sndmsg_off;
1142 			unsigned int left;
1143 
1144 			if (page && (left = PAGE_SIZE - off) > 0) {
1145 				if (copy >= left)
1146 					copy = left;
1147 				if (page != frag->page) {
1148 					if (i == MAX_SKB_FRAGS) {
1149 						err = -EMSGSIZE;
1150 						goto error;
1151 					}
1152 					get_page(page);
1153 					skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1154 					frag = &skb_shinfo(skb)->frags[i];
1155 				}
1156 			} else if(i < MAX_SKB_FRAGS) {
1157 				if (copy > PAGE_SIZE)
1158 					copy = PAGE_SIZE;
1159 				page = alloc_pages(sk->sk_allocation, 0);
1160 				if (page == NULL) {
1161 					err = -ENOMEM;
1162 					goto error;
1163 				}
1164 				sk->sk_sndmsg_page = page;
1165 				sk->sk_sndmsg_off = 0;
1166 
1167 				skb_fill_page_desc(skb, i, page, 0, 0);
1168 				frag = &skb_shinfo(skb)->frags[i];
1169 				skb->truesize += PAGE_SIZE;
1170 				atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
1171 			} else {
1172 				err = -EMSGSIZE;
1173 				goto error;
1174 			}
1175 			if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1176 				err = -EFAULT;
1177 				goto error;
1178 			}
1179 			sk->sk_sndmsg_off += copy;
1180 			frag->size += copy;
1181 			skb->len += copy;
1182 			skb->data_len += copy;
1183 		}
1184 		offset += copy;
1185 		length -= copy;
1186 	}
1187 	return 0;
1188 error:
1189 	inet->cork.length -= length;
1190 	IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
1191 	return err;
1192 }
1193 
1194 int ip6_push_pending_frames(struct sock *sk)
1195 {
1196 	struct sk_buff *skb, *tmp_skb;
1197 	struct sk_buff **tail_skb;
1198 	struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1199 	struct inet_sock *inet = inet_sk(sk);
1200 	struct ipv6_pinfo *np = inet6_sk(sk);
1201 	struct ipv6hdr *hdr;
1202 	struct ipv6_txoptions *opt = np->cork.opt;
1203 	struct rt6_info *rt = np->cork.rt;
1204 	struct flowi *fl = &inet->cork.fl;
1205 	unsigned char proto = fl->proto;
1206 	int err = 0;
1207 
1208 	if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1209 		goto out;
1210 	tail_skb = &(skb_shinfo(skb)->frag_list);
1211 
1212 	/* move skb->data to ip header from ext header */
1213 	if (skb->data < skb->nh.raw)
1214 		__skb_pull(skb, skb->nh.raw - skb->data);
1215 	while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1216 		__skb_pull(tmp_skb, skb->h.raw - skb->nh.raw);
1217 		*tail_skb = tmp_skb;
1218 		tail_skb = &(tmp_skb->next);
1219 		skb->len += tmp_skb->len;
1220 		skb->data_len += tmp_skb->len;
1221 		skb->truesize += tmp_skb->truesize;
1222 		__sock_put(tmp_skb->sk);
1223 		tmp_skb->destructor = NULL;
1224 		tmp_skb->sk = NULL;
1225 	}
1226 
1227 	ipv6_addr_copy(final_dst, &fl->fl6_dst);
1228 	__skb_pull(skb, skb->h.raw - skb->nh.raw);
1229 	if (opt && opt->opt_flen)
1230 		ipv6_push_frag_opts(skb, opt, &proto);
1231 	if (opt && opt->opt_nflen)
1232 		ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1233 
1234 	skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr));
1235 
1236 	*(u32*)hdr = fl->fl6_flowlabel |
1237 		     htonl(0x60000000 | ((int)np->cork.tclass << 20));
1238 
1239 	if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN)
1240 		hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
1241 	else
1242 		hdr->payload_len = 0;
1243 	hdr->hop_limit = np->cork.hop_limit;
1244 	hdr->nexthdr = proto;
1245 	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
1246 	ipv6_addr_copy(&hdr->daddr, final_dst);
1247 
1248 	skb->priority = sk->sk_priority;
1249 
1250 	skb->dst = dst_clone(&rt->u.dst);
1251 	IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
1252 	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output);
1253 	if (err) {
1254 		if (err > 0)
1255 			err = np->recverr ? net_xmit_errno(err) : 0;
1256 		if (err)
1257 			goto error;
1258 	}
1259 
1260 out:
1261 	inet->cork.flags &= ~IPCORK_OPT;
1262 	kfree(np->cork.opt);
1263 	np->cork.opt = NULL;
1264 	if (np->cork.rt) {
1265 		dst_release(&np->cork.rt->u.dst);
1266 		np->cork.rt = NULL;
1267 		inet->cork.flags &= ~IPCORK_ALLFRAG;
1268 	}
1269 	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1270 	return err;
1271 error:
1272 	goto out;
1273 }
1274 
1275 void ip6_flush_pending_frames(struct sock *sk)
1276 {
1277 	struct inet_sock *inet = inet_sk(sk);
1278 	struct ipv6_pinfo *np = inet6_sk(sk);
1279 	struct sk_buff *skb;
1280 
1281 	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1282 		IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
1283 		kfree_skb(skb);
1284 	}
1285 
1286 	inet->cork.flags &= ~IPCORK_OPT;
1287 
1288 	kfree(np->cork.opt);
1289 	np->cork.opt = NULL;
1290 	if (np->cork.rt) {
1291 		dst_release(&np->cork.rt->u.dst);
1292 		np->cork.rt = NULL;
1293 		inet->cork.flags &= ~IPCORK_ALLFRAG;
1294 	}
1295 	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1296 }
1297