xref: /openbmc/linux/net/ipv6/ip6_output.c (revision c21b37f6)
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 	struct dst_entry *dst = skb->dst;
76 
77 	if (dst->hh)
78 		return neigh_hh_output(dst->hh, skb);
79 	else if (dst->neighbour)
80 		return dst->neighbour->output(skb);
81 
82 	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
83 	kfree_skb(skb);
84 	return -EINVAL;
85 
86 }
87 
88 /* dev_loopback_xmit for use with netfilter. */
89 static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
90 {
91 	skb_reset_mac_header(newskb);
92 	__skb_pull(newskb, skb_network_offset(newskb));
93 	newskb->pkt_type = PACKET_LOOPBACK;
94 	newskb->ip_summed = CHECKSUM_UNNECESSARY;
95 	BUG_TRAP(newskb->dst);
96 
97 	netif_rx(newskb);
98 	return 0;
99 }
100 
101 
102 static int ip6_output2(struct sk_buff *skb)
103 {
104 	struct dst_entry *dst = skb->dst;
105 	struct net_device *dev = dst->dev;
106 
107 	skb->protocol = htons(ETH_P_IPV6);
108 	skb->dev = dev;
109 
110 	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
111 		struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;
112 		struct inet6_dev *idev = ip6_dst_idev(skb->dst);
113 
114 		if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
115 		    ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
116 					&ipv6_hdr(skb)->saddr)) {
117 			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
118 
119 			/* Do not check for IFF_ALLMULTI; multicast routing
120 			   is not supported in any case.
121 			 */
122 			if (newskb)
123 				NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL,
124 					newskb->dev,
125 					ip6_dev_loopback_xmit);
126 
127 			if (ipv6_hdr(skb)->hop_limit == 0) {
128 				IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS);
129 				kfree_skb(skb);
130 				return 0;
131 			}
132 		}
133 
134 		IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS);
135 	}
136 
137 	return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish);
138 }
139 
140 static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
141 {
142 	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
143 
144 	return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ?
145 	       skb->dst->dev->mtu : dst_mtu(skb->dst);
146 }
147 
148 int ip6_output(struct sk_buff *skb)
149 {
150 	if ((skb->len > ip6_skb_dst_mtu(skb) && !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 			if (skb2 == NULL) {
186 				IP6_INC_STATS(ip6_dst_idev(skb->dst),
187 					      IPSTATS_MIB_OUTDISCARDS);
188 				kfree_skb(skb);
189 				return -ENOBUFS;
190 			}
191 			kfree_skb(skb);
192 			skb = skb2;
193 			if (sk)
194 				skb_set_owner_w(skb, sk);
195 		}
196 		if (opt->opt_flen)
197 			ipv6_push_frag_opts(skb, opt, &proto);
198 		if (opt->opt_nflen)
199 			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
200 	}
201 
202 	skb_push(skb, sizeof(struct ipv6hdr));
203 	skb_reset_network_header(skb);
204 	hdr = ipv6_hdr(skb);
205 
206 	/*
207 	 *	Fill in the IPv6 header
208 	 */
209 
210 	hlimit = -1;
211 	if (np)
212 		hlimit = np->hop_limit;
213 	if (hlimit < 0)
214 		hlimit = dst_metric(dst, RTAX_HOPLIMIT);
215 	if (hlimit < 0)
216 		hlimit = ipv6_get_hoplimit(dst->dev);
217 
218 	tclass = -1;
219 	if (np)
220 		tclass = np->tclass;
221 	if (tclass < 0)
222 		tclass = 0;
223 
224 	*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;
225 
226 	hdr->payload_len = htons(seg_len);
227 	hdr->nexthdr = proto;
228 	hdr->hop_limit = hlimit;
229 
230 	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
231 	ipv6_addr_copy(&hdr->daddr, first_hop);
232 
233 	skb->priority = sk->sk_priority;
234 
235 	mtu = dst_mtu(dst);
236 	if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
237 		IP6_INC_STATS(ip6_dst_idev(skb->dst),
238 			      IPSTATS_MIB_OUTREQUESTS);
239 		return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
240 				dst_output);
241 	}
242 
243 	if (net_ratelimit())
244 		printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
245 	skb->dev = dst->dev;
246 	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
247 	IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
248 	kfree_skb(skb);
249 	return -EMSGSIZE;
250 }
251 
252 EXPORT_SYMBOL(ip6_xmit);
253 
254 /*
255  *	To avoid extra problems ND packets are send through this
256  *	routine. It's code duplication but I really want to avoid
257  *	extra checks since ipv6_build_header is used by TCP (which
258  *	is for us performance critical)
259  */
260 
261 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
262 	       struct in6_addr *saddr, struct in6_addr *daddr,
263 	       int proto, int len)
264 {
265 	struct ipv6_pinfo *np = inet6_sk(sk);
266 	struct ipv6hdr *hdr;
267 	int totlen;
268 
269 	skb->protocol = htons(ETH_P_IPV6);
270 	skb->dev = dev;
271 
272 	totlen = len + sizeof(struct ipv6hdr);
273 
274 	skb_reset_network_header(skb);
275 	skb_put(skb, sizeof(struct ipv6hdr));
276 	hdr = ipv6_hdr(skb);
277 
278 	*(__be32*)hdr = htonl(0x60000000);
279 
280 	hdr->payload_len = htons(len);
281 	hdr->nexthdr = proto;
282 	hdr->hop_limit = np->hop_limit;
283 
284 	ipv6_addr_copy(&hdr->saddr, saddr);
285 	ipv6_addr_copy(&hdr->daddr, daddr);
286 
287 	return 0;
288 }
289 
290 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
291 {
292 	struct ip6_ra_chain *ra;
293 	struct sock *last = NULL;
294 
295 	read_lock(&ip6_ra_lock);
296 	for (ra = ip6_ra_chain; ra; ra = ra->next) {
297 		struct sock *sk = ra->sk;
298 		if (sk && ra->sel == sel &&
299 		    (!sk->sk_bound_dev_if ||
300 		     sk->sk_bound_dev_if == skb->dev->ifindex)) {
301 			if (last) {
302 				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
303 				if (skb2)
304 					rawv6_rcv(last, skb2);
305 			}
306 			last = sk;
307 		}
308 	}
309 
310 	if (last) {
311 		rawv6_rcv(last, skb);
312 		read_unlock(&ip6_ra_lock);
313 		return 1;
314 	}
315 	read_unlock(&ip6_ra_lock);
316 	return 0;
317 }
318 
319 static int ip6_forward_proxy_check(struct sk_buff *skb)
320 {
321 	struct ipv6hdr *hdr = ipv6_hdr(skb);
322 	u8 nexthdr = hdr->nexthdr;
323 	int offset;
324 
325 	if (ipv6_ext_hdr(nexthdr)) {
326 		offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
327 		if (offset < 0)
328 			return 0;
329 	} else
330 		offset = sizeof(struct ipv6hdr);
331 
332 	if (nexthdr == IPPROTO_ICMPV6) {
333 		struct icmp6hdr *icmp6;
334 
335 		if (!pskb_may_pull(skb, (skb_network_header(skb) +
336 					 offset + 1 - skb->data)))
337 			return 0;
338 
339 		icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
340 
341 		switch (icmp6->icmp6_type) {
342 		case NDISC_ROUTER_SOLICITATION:
343 		case NDISC_ROUTER_ADVERTISEMENT:
344 		case NDISC_NEIGHBOUR_SOLICITATION:
345 		case NDISC_NEIGHBOUR_ADVERTISEMENT:
346 		case NDISC_REDIRECT:
347 			/* For reaction involving unicast neighbor discovery
348 			 * message destined to the proxied address, pass it to
349 			 * input function.
350 			 */
351 			return 1;
352 		default:
353 			break;
354 		}
355 	}
356 
357 	/*
358 	 * The proxying router can't forward traffic sent to a link-local
359 	 * address, so signal the sender and discard the packet. This
360 	 * behavior is clarified by the MIPv6 specification.
361 	 */
362 	if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
363 		dst_link_failure(skb);
364 		return -1;
365 	}
366 
367 	return 0;
368 }
369 
370 static inline int ip6_forward_finish(struct sk_buff *skb)
371 {
372 	return dst_output(skb);
373 }
374 
375 int ip6_forward(struct sk_buff *skb)
376 {
377 	struct dst_entry *dst = skb->dst;
378 	struct ipv6hdr *hdr = ipv6_hdr(skb);
379 	struct inet6_skb_parm *opt = IP6CB(skb);
380 
381 	if (ipv6_devconf.forwarding == 0)
382 		goto error;
383 
384 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
385 		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
386 		goto drop;
387 	}
388 
389 	skb_forward_csum(skb);
390 
391 	/*
392 	 *	We DO NOT make any processing on
393 	 *	RA packets, pushing them to user level AS IS
394 	 *	without ane WARRANTY that application will be able
395 	 *	to interpret them. The reason is that we
396 	 *	cannot make anything clever here.
397 	 *
398 	 *	We are not end-node, so that if packet contains
399 	 *	AH/ESP, we cannot make anything.
400 	 *	Defragmentation also would be mistake, RA packets
401 	 *	cannot be fragmented, because there is no warranty
402 	 *	that different fragments will go along one path. --ANK
403 	 */
404 	if (opt->ra) {
405 		u8 *ptr = skb_network_header(skb) + opt->ra;
406 		if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
407 			return 0;
408 	}
409 
410 	/*
411 	 *	check and decrement ttl
412 	 */
413 	if (hdr->hop_limit <= 1) {
414 		/* Force OUTPUT device used as source address */
415 		skb->dev = dst->dev;
416 		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
417 			    0, skb->dev);
418 		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
419 
420 		kfree_skb(skb);
421 		return -ETIMEDOUT;
422 	}
423 
424 	/* XXX: idev->cnf.proxy_ndp? */
425 	if (ipv6_devconf.proxy_ndp &&
426 	    pneigh_lookup(&nd_tbl, &hdr->daddr, skb->dev, 0)) {
427 		int proxied = ip6_forward_proxy_check(skb);
428 		if (proxied > 0)
429 			return ip6_input(skb);
430 		else if (proxied < 0) {
431 			IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
432 			goto drop;
433 		}
434 	}
435 
436 	if (!xfrm6_route_forward(skb)) {
437 		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
438 		goto drop;
439 	}
440 	dst = skb->dst;
441 
442 	/* IPv6 specs say nothing about it, but it is clear that we cannot
443 	   send redirects to source routed frames.
444 	 */
445 	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
446 		struct in6_addr *target = NULL;
447 		struct rt6_info *rt;
448 		struct neighbour *n = dst->neighbour;
449 
450 		/*
451 		 *	incoming and outgoing devices are the same
452 		 *	send a redirect.
453 		 */
454 
455 		rt = (struct rt6_info *) dst;
456 		if ((rt->rt6i_flags & RTF_GATEWAY))
457 			target = (struct in6_addr*)&n->primary_key;
458 		else
459 			target = &hdr->daddr;
460 
461 		/* Limit redirects both by destination (here)
462 		   and by source (inside ndisc_send_redirect)
463 		 */
464 		if (xrlim_allow(dst, 1*HZ))
465 			ndisc_send_redirect(skb, n, target);
466 	} else {
467 		int addrtype = ipv6_addr_type(&hdr->saddr);
468 
469 		/* This check is security critical. */
470 		if (addrtype & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK))
471 			goto error;
472 		if (addrtype & IPV6_ADDR_LINKLOCAL) {
473 			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
474 				ICMPV6_NOT_NEIGHBOUR, 0, skb->dev);
475 			goto error;
476 		}
477 	}
478 
479 	if (skb->len > dst_mtu(dst)) {
480 		/* Again, force OUTPUT device used as source address */
481 		skb->dev = dst->dev;
482 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
483 		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
484 		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
485 		kfree_skb(skb);
486 		return -EMSGSIZE;
487 	}
488 
489 	if (skb_cow(skb, dst->dev->hard_header_len)) {
490 		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
491 		goto drop;
492 	}
493 
494 	hdr = ipv6_hdr(skb);
495 
496 	/* Mangling hops number delayed to point after skb COW */
497 
498 	hdr->hop_limit--;
499 
500 	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
501 	return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish);
502 
503 error:
504 	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
505 drop:
506 	kfree_skb(skb);
507 	return -EINVAL;
508 }
509 
510 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
511 {
512 	to->pkt_type = from->pkt_type;
513 	to->priority = from->priority;
514 	to->protocol = from->protocol;
515 	dst_release(to->dst);
516 	to->dst = dst_clone(from->dst);
517 	to->dev = from->dev;
518 	to->mark = from->mark;
519 
520 #ifdef CONFIG_NET_SCHED
521 	to->tc_index = from->tc_index;
522 #endif
523 	nf_copy(to, from);
524 #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
525     defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
526 	to->nf_trace = from->nf_trace;
527 #endif
528 	skb_copy_secmark(to, from);
529 }
530 
531 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
532 {
533 	u16 offset = sizeof(struct ipv6hdr);
534 	struct ipv6_opt_hdr *exthdr =
535 				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
536 	unsigned int packet_len = skb->tail - skb->network_header;
537 	int found_rhdr = 0;
538 	*nexthdr = &ipv6_hdr(skb)->nexthdr;
539 
540 	while (offset + 1 <= packet_len) {
541 
542 		switch (**nexthdr) {
543 
544 		case NEXTHDR_HOP:
545 			break;
546 		case NEXTHDR_ROUTING:
547 			found_rhdr = 1;
548 			break;
549 		case NEXTHDR_DEST:
550 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
551 			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
552 				break;
553 #endif
554 			if (found_rhdr)
555 				return offset;
556 			break;
557 		default :
558 			return offset;
559 		}
560 
561 		offset += ipv6_optlen(exthdr);
562 		*nexthdr = &exthdr->nexthdr;
563 		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
564 						 offset);
565 	}
566 
567 	return offset;
568 }
569 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
570 
571 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
572 {
573 	struct net_device *dev;
574 	struct sk_buff *frag;
575 	struct rt6_info *rt = (struct rt6_info*)skb->dst;
576 	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
577 	struct ipv6hdr *tmp_hdr;
578 	struct frag_hdr *fh;
579 	unsigned int mtu, hlen, left, len;
580 	__be32 frag_id = 0;
581 	int ptr, offset = 0, err=0;
582 	u8 *prevhdr, nexthdr = 0;
583 
584 	dev = rt->u.dst.dev;
585 	hlen = ip6_find_1stfragopt(skb, &prevhdr);
586 	nexthdr = *prevhdr;
587 
588 	mtu = ip6_skb_dst_mtu(skb);
589 
590 	/* We must not fragment if the socket is set to force MTU discovery
591 	 * or if the skb it not generated by a local socket.  (This last
592 	 * check should be redundant, but it's free.)
593 	 */
594 	if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) {
595 		skb->dev = skb->dst->dev;
596 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
597 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
598 		kfree_skb(skb);
599 		return -EMSGSIZE;
600 	}
601 
602 	if (np && np->frag_size < mtu) {
603 		if (np->frag_size)
604 			mtu = np->frag_size;
605 	}
606 	mtu -= hlen + sizeof(struct frag_hdr);
607 
608 	if (skb_shinfo(skb)->frag_list) {
609 		int first_len = skb_pagelen(skb);
610 
611 		if (first_len - hlen > mtu ||
612 		    ((first_len - hlen) & 7) ||
613 		    skb_cloned(skb))
614 			goto slow_path;
615 
616 		for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
617 			/* Correct geometry. */
618 			if (frag->len > mtu ||
619 			    ((frag->len & 7) && frag->next) ||
620 			    skb_headroom(frag) < hlen)
621 			    goto slow_path;
622 
623 			/* Partially cloned skb? */
624 			if (skb_shared(frag))
625 				goto slow_path;
626 
627 			BUG_ON(frag->sk);
628 			if (skb->sk) {
629 				sock_hold(skb->sk);
630 				frag->sk = skb->sk;
631 				frag->destructor = sock_wfree;
632 				skb->truesize -= frag->truesize;
633 			}
634 		}
635 
636 		err = 0;
637 		offset = 0;
638 		frag = skb_shinfo(skb)->frag_list;
639 		skb_shinfo(skb)->frag_list = NULL;
640 		/* BUILD HEADER */
641 
642 		*prevhdr = NEXTHDR_FRAGMENT;
643 		tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
644 		if (!tmp_hdr) {
645 			IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
646 			return -ENOMEM;
647 		}
648 
649 		__skb_pull(skb, hlen);
650 		fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
651 		__skb_push(skb, hlen);
652 		skb_reset_network_header(skb);
653 		memcpy(skb_network_header(skb), tmp_hdr, hlen);
654 
655 		ipv6_select_ident(skb, fh);
656 		fh->nexthdr = nexthdr;
657 		fh->reserved = 0;
658 		fh->frag_off = htons(IP6_MF);
659 		frag_id = fh->identification;
660 
661 		first_len = skb_pagelen(skb);
662 		skb->data_len = first_len - skb_headlen(skb);
663 		skb->len = first_len;
664 		ipv6_hdr(skb)->payload_len = htons(first_len -
665 						   sizeof(struct ipv6hdr));
666 
667 		dst_hold(&rt->u.dst);
668 
669 		for (;;) {
670 			/* Prepare header of the next frame,
671 			 * before previous one went down. */
672 			if (frag) {
673 				frag->ip_summed = CHECKSUM_NONE;
674 				skb_reset_transport_header(frag);
675 				fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
676 				__skb_push(frag, hlen);
677 				skb_reset_network_header(frag);
678 				memcpy(skb_network_header(frag), tmp_hdr,
679 				       hlen);
680 				offset += skb->len - hlen - sizeof(struct frag_hdr);
681 				fh->nexthdr = nexthdr;
682 				fh->reserved = 0;
683 				fh->frag_off = htons(offset);
684 				if (frag->next != NULL)
685 					fh->frag_off |= htons(IP6_MF);
686 				fh->identification = frag_id;
687 				ipv6_hdr(frag)->payload_len =
688 						htons(frag->len -
689 						      sizeof(struct ipv6hdr));
690 				ip6_copy_metadata(frag, skb);
691 			}
692 
693 			err = output(skb);
694 			if(!err)
695 				IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGCREATES);
696 
697 			if (err || !frag)
698 				break;
699 
700 			skb = frag;
701 			frag = skb->next;
702 			skb->next = NULL;
703 		}
704 
705 		kfree(tmp_hdr);
706 
707 		if (err == 0) {
708 			IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGOKS);
709 			dst_release(&rt->u.dst);
710 			return 0;
711 		}
712 
713 		while (frag) {
714 			skb = frag->next;
715 			kfree_skb(frag);
716 			frag = skb;
717 		}
718 
719 		IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGFAILS);
720 		dst_release(&rt->u.dst);
721 		return err;
722 	}
723 
724 slow_path:
725 	left = skb->len - hlen;		/* Space per frame */
726 	ptr = hlen;			/* Where to start from */
727 
728 	/*
729 	 *	Fragment the datagram.
730 	 */
731 
732 	*prevhdr = NEXTHDR_FRAGMENT;
733 
734 	/*
735 	 *	Keep copying data until we run out.
736 	 */
737 	while(left > 0)	{
738 		len = left;
739 		/* IF: it doesn't fit, use 'mtu' - the data space left */
740 		if (len > mtu)
741 			len = mtu;
742 		/* IF: we are not sending upto and including the packet end
743 		   then align the next start on an eight byte boundary */
744 		if (len < left)	{
745 			len &= ~7;
746 		}
747 		/*
748 		 *	Allocate buffer.
749 		 */
750 
751 		if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
752 			NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
753 			IP6_INC_STATS(ip6_dst_idev(skb->dst),
754 				      IPSTATS_MIB_FRAGFAILS);
755 			err = -ENOMEM;
756 			goto fail;
757 		}
758 
759 		/*
760 		 *	Set up data on packet
761 		 */
762 
763 		ip6_copy_metadata(frag, skb);
764 		skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
765 		skb_put(frag, len + hlen + sizeof(struct frag_hdr));
766 		skb_reset_network_header(frag);
767 		fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
768 		frag->transport_header = (frag->network_header + hlen +
769 					  sizeof(struct frag_hdr));
770 
771 		/*
772 		 *	Charge the memory for the fragment to any owner
773 		 *	it might possess
774 		 */
775 		if (skb->sk)
776 			skb_set_owner_w(frag, skb->sk);
777 
778 		/*
779 		 *	Copy the packet header into the new buffer.
780 		 */
781 		skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
782 
783 		/*
784 		 *	Build fragment header.
785 		 */
786 		fh->nexthdr = nexthdr;
787 		fh->reserved = 0;
788 		if (!frag_id) {
789 			ipv6_select_ident(skb, fh);
790 			frag_id = fh->identification;
791 		} else
792 			fh->identification = frag_id;
793 
794 		/*
795 		 *	Copy a block of the IP datagram.
796 		 */
797 		if (skb_copy_bits(skb, ptr, skb_transport_header(skb), len))
798 			BUG();
799 		left -= len;
800 
801 		fh->frag_off = htons(offset);
802 		if (left > 0)
803 			fh->frag_off |= htons(IP6_MF);
804 		ipv6_hdr(frag)->payload_len = htons(frag->len -
805 						    sizeof(struct ipv6hdr));
806 
807 		ptr += len;
808 		offset += len;
809 
810 		/*
811 		 *	Put this fragment into the sending queue.
812 		 */
813 		err = output(frag);
814 		if (err)
815 			goto fail;
816 
817 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGCREATES);
818 	}
819 	IP6_INC_STATS(ip6_dst_idev(skb->dst),
820 		      IPSTATS_MIB_FRAGOKS);
821 	kfree_skb(skb);
822 	return err;
823 
824 fail:
825 	IP6_INC_STATS(ip6_dst_idev(skb->dst),
826 		      IPSTATS_MIB_FRAGFAILS);
827 	kfree_skb(skb);
828 	return err;
829 }
830 
831 static inline int ip6_rt_check(struct rt6key *rt_key,
832 			       struct in6_addr *fl_addr,
833 			       struct in6_addr *addr_cache)
834 {
835 	return ((rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
836 		(addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)));
837 }
838 
839 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
840 					  struct dst_entry *dst,
841 					  struct flowi *fl)
842 {
843 	struct ipv6_pinfo *np = inet6_sk(sk);
844 	struct rt6_info *rt = (struct rt6_info *)dst;
845 
846 	if (!dst)
847 		goto out;
848 
849 	/* Yes, checking route validity in not connected
850 	 * case is not very simple. Take into account,
851 	 * that we do not support routing by source, TOS,
852 	 * and MSG_DONTROUTE 		--ANK (980726)
853 	 *
854 	 * 1. ip6_rt_check(): If route was host route,
855 	 *    check that cached destination is current.
856 	 *    If it is network route, we still may
857 	 *    check its validity using saved pointer
858 	 *    to the last used address: daddr_cache.
859 	 *    We do not want to save whole address now,
860 	 *    (because main consumer of this service
861 	 *    is tcp, which has not this problem),
862 	 *    so that the last trick works only on connected
863 	 *    sockets.
864 	 * 2. oif also should be the same.
865 	 */
866 	if (ip6_rt_check(&rt->rt6i_dst, &fl->fl6_dst, np->daddr_cache) ||
867 #ifdef CONFIG_IPV6_SUBTREES
868 	    ip6_rt_check(&rt->rt6i_src, &fl->fl6_src, np->saddr_cache) ||
869 #endif
870 	    (fl->oif && fl->oif != dst->dev->ifindex)) {
871 		dst_release(dst);
872 		dst = NULL;
873 	}
874 
875 out:
876 	return dst;
877 }
878 
879 static int ip6_dst_lookup_tail(struct sock *sk,
880 			       struct dst_entry **dst, struct flowi *fl)
881 {
882 	int err;
883 
884 	if (*dst == NULL)
885 		*dst = ip6_route_output(sk, fl);
886 
887 	if ((err = (*dst)->error))
888 		goto out_err_release;
889 
890 	if (ipv6_addr_any(&fl->fl6_src)) {
891 		err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);
892 		if (err)
893 			goto out_err_release;
894 	}
895 
896 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
897 		/*
898 		 * Here if the dst entry we've looked up
899 		 * has a neighbour entry that is in the INCOMPLETE
900 		 * state and the src address from the flow is
901 		 * marked as OPTIMISTIC, we release the found
902 		 * dst entry and replace it instead with the
903 		 * dst entry of the nexthop router
904 		 */
905 		if (!((*dst)->neighbour->nud_state & NUD_VALID)) {
906 			struct inet6_ifaddr *ifp;
907 			struct flowi fl_gw;
908 			int redirect;
909 
910 			ifp = ipv6_get_ifaddr(&fl->fl6_src, (*dst)->dev, 1);
911 
912 			redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
913 			if (ifp)
914 				in6_ifa_put(ifp);
915 
916 			if (redirect) {
917 				/*
918 				 * We need to get the dst entry for the
919 				 * default router instead
920 				 */
921 				dst_release(*dst);
922 				memcpy(&fl_gw, fl, sizeof(struct flowi));
923 				memset(&fl_gw.fl6_dst, 0, sizeof(struct in6_addr));
924 				*dst = ip6_route_output(sk, &fl_gw);
925 				if ((err = (*dst)->error))
926 					goto out_err_release;
927 			}
928 		}
929 #endif
930 
931 	return 0;
932 
933 out_err_release:
934 	dst_release(*dst);
935 	*dst = NULL;
936 	return err;
937 }
938 
939 /**
940  *	ip6_dst_lookup - perform route lookup on flow
941  *	@sk: socket which provides route info
942  *	@dst: pointer to dst_entry * for result
943  *	@fl: flow to lookup
944  *
945  *	This function performs a route lookup on the given flow.
946  *
947  *	It returns zero on success, or a standard errno code on error.
948  */
949 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
950 {
951 	*dst = NULL;
952 	return ip6_dst_lookup_tail(sk, dst, fl);
953 }
954 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
955 
956 /**
957  *	ip6_sk_dst_lookup - perform socket cached route lookup on flow
958  *	@sk: socket which provides the dst cache and route info
959  *	@dst: pointer to dst_entry * for result
960  *	@fl: flow to lookup
961  *
962  *	This function performs a route lookup on the given flow with the
963  *	possibility of using the cached route in the socket if it is valid.
964  *	It will take the socket dst lock when operating on the dst cache.
965  *	As a result, this function can only be used in process context.
966  *
967  *	It returns zero on success, or a standard errno code on error.
968  */
969 int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
970 {
971 	*dst = NULL;
972 	if (sk) {
973 		*dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
974 		*dst = ip6_sk_dst_check(sk, *dst, fl);
975 	}
976 
977 	return ip6_dst_lookup_tail(sk, dst, fl);
978 }
979 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup);
980 
981 static inline int ip6_ufo_append_data(struct sock *sk,
982 			int getfrag(void *from, char *to, int offset, int len,
983 			int odd, struct sk_buff *skb),
984 			void *from, int length, int hh_len, int fragheaderlen,
985 			int transhdrlen, int mtu,unsigned int flags)
986 
987 {
988 	struct sk_buff *skb;
989 	int err;
990 
991 	/* There is support for UDP large send offload by network
992 	 * device, so create one single skb packet containing complete
993 	 * udp datagram
994 	 */
995 	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
996 		skb = sock_alloc_send_skb(sk,
997 			hh_len + fragheaderlen + transhdrlen + 20,
998 			(flags & MSG_DONTWAIT), &err);
999 		if (skb == NULL)
1000 			return -ENOMEM;
1001 
1002 		/* reserve space for Hardware header */
1003 		skb_reserve(skb, hh_len);
1004 
1005 		/* create space for UDP/IP header */
1006 		skb_put(skb,fragheaderlen + transhdrlen);
1007 
1008 		/* initialize network header pointer */
1009 		skb_reset_network_header(skb);
1010 
1011 		/* initialize protocol header pointer */
1012 		skb->transport_header = skb->network_header + fragheaderlen;
1013 
1014 		skb->ip_summed = CHECKSUM_PARTIAL;
1015 		skb->csum = 0;
1016 		sk->sk_sndmsg_off = 0;
1017 	}
1018 
1019 	err = skb_append_datato_frags(sk,skb, getfrag, from,
1020 				      (length - transhdrlen));
1021 	if (!err) {
1022 		struct frag_hdr fhdr;
1023 
1024 		/* specify the length of each IP datagram fragment*/
1025 		skb_shinfo(skb)->gso_size = mtu - fragheaderlen -
1026 					    sizeof(struct frag_hdr);
1027 		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1028 		ipv6_select_ident(skb, &fhdr);
1029 		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1030 		__skb_queue_tail(&sk->sk_write_queue, skb);
1031 
1032 		return 0;
1033 	}
1034 	/* There is not enough support do UPD LSO,
1035 	 * so follow normal path
1036 	 */
1037 	kfree_skb(skb);
1038 
1039 	return err;
1040 }
1041 
1042 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1043 	int offset, int len, int odd, struct sk_buff *skb),
1044 	void *from, int length, int transhdrlen,
1045 	int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
1046 	struct rt6_info *rt, unsigned int flags)
1047 {
1048 	struct inet_sock *inet = inet_sk(sk);
1049 	struct ipv6_pinfo *np = inet6_sk(sk);
1050 	struct sk_buff *skb;
1051 	unsigned int maxfraglen, fragheaderlen;
1052 	int exthdrlen;
1053 	int hh_len;
1054 	int mtu;
1055 	int copy;
1056 	int err;
1057 	int offset = 0;
1058 	int csummode = CHECKSUM_NONE;
1059 
1060 	if (flags&MSG_PROBE)
1061 		return 0;
1062 	if (skb_queue_empty(&sk->sk_write_queue)) {
1063 		/*
1064 		 * setup for corking
1065 		 */
1066 		if (opt) {
1067 			if (np->cork.opt == NULL) {
1068 				np->cork.opt = kmalloc(opt->tot_len,
1069 						       sk->sk_allocation);
1070 				if (unlikely(np->cork.opt == NULL))
1071 					return -ENOBUFS;
1072 			} else if (np->cork.opt->tot_len < opt->tot_len) {
1073 				printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
1074 				return -EINVAL;
1075 			}
1076 			memcpy(np->cork.opt, opt, opt->tot_len);
1077 			inet->cork.flags |= IPCORK_OPT;
1078 			/* need source address above miyazawa*/
1079 		}
1080 		dst_hold(&rt->u.dst);
1081 		np->cork.rt = rt;
1082 		inet->cork.fl = *fl;
1083 		np->cork.hop_limit = hlimit;
1084 		np->cork.tclass = tclass;
1085 		mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1086 		      rt->u.dst.dev->mtu : dst_mtu(rt->u.dst.path);
1087 		if (np->frag_size < mtu) {
1088 			if (np->frag_size)
1089 				mtu = np->frag_size;
1090 		}
1091 		inet->cork.fragsize = mtu;
1092 		if (dst_allfrag(rt->u.dst.path))
1093 			inet->cork.flags |= IPCORK_ALLFRAG;
1094 		inet->cork.length = 0;
1095 		sk->sk_sndmsg_page = NULL;
1096 		sk->sk_sndmsg_off = 0;
1097 		exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0);
1098 		length += exthdrlen;
1099 		transhdrlen += exthdrlen;
1100 	} else {
1101 		rt = np->cork.rt;
1102 		fl = &inet->cork.fl;
1103 		if (inet->cork.flags & IPCORK_OPT)
1104 			opt = np->cork.opt;
1105 		transhdrlen = 0;
1106 		exthdrlen = 0;
1107 		mtu = inet->cork.fragsize;
1108 	}
1109 
1110 	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
1111 
1112 	fragheaderlen = sizeof(struct ipv6hdr) + rt->u.dst.nfheader_len + (opt ? opt->opt_nflen : 0);
1113 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1114 
1115 	if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1116 		if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1117 			ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
1118 			return -EMSGSIZE;
1119 		}
1120 	}
1121 
1122 	/*
1123 	 * Let's try using as much space as possible.
1124 	 * Use MTU if total length of the message fits into the MTU.
1125 	 * Otherwise, we need to reserve fragment header and
1126 	 * fragment alignment (= 8-15 octects, in total).
1127 	 *
1128 	 * Note that we may need to "move" the data from the tail of
1129 	 * of the buffer to the new fragment when we split
1130 	 * the message.
1131 	 *
1132 	 * FIXME: It may be fragmented into multiple chunks
1133 	 *        at once if non-fragmentable extension headers
1134 	 *        are too large.
1135 	 * --yoshfuji
1136 	 */
1137 
1138 	inet->cork.length += length;
1139 	if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
1140 	    (rt->u.dst.dev->features & NETIF_F_UFO)) {
1141 
1142 		err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
1143 					  fragheaderlen, transhdrlen, mtu,
1144 					  flags);
1145 		if (err)
1146 			goto error;
1147 		return 0;
1148 	}
1149 
1150 	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1151 		goto alloc_new_skb;
1152 
1153 	while (length > 0) {
1154 		/* Check if the remaining data fits into current packet. */
1155 		copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1156 		if (copy < length)
1157 			copy = maxfraglen - skb->len;
1158 
1159 		if (copy <= 0) {
1160 			char *data;
1161 			unsigned int datalen;
1162 			unsigned int fraglen;
1163 			unsigned int fraggap;
1164 			unsigned int alloclen;
1165 			struct sk_buff *skb_prev;
1166 alloc_new_skb:
1167 			skb_prev = skb;
1168 
1169 			/* There's no room in the current skb */
1170 			if (skb_prev)
1171 				fraggap = skb_prev->len - maxfraglen;
1172 			else
1173 				fraggap = 0;
1174 
1175 			/*
1176 			 * If remaining data exceeds the mtu,
1177 			 * we know we need more fragment(s).
1178 			 */
1179 			datalen = length + fraggap;
1180 			if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1181 				datalen = maxfraglen - fragheaderlen;
1182 
1183 			fraglen = datalen + fragheaderlen;
1184 			if ((flags & MSG_MORE) &&
1185 			    !(rt->u.dst.dev->features&NETIF_F_SG))
1186 				alloclen = mtu;
1187 			else
1188 				alloclen = datalen + fragheaderlen;
1189 
1190 			/*
1191 			 * The last fragment gets additional space at tail.
1192 			 * Note: we overallocate on fragments with MSG_MODE
1193 			 * because we have no idea if we're the last one.
1194 			 */
1195 			if (datalen == length + fraggap)
1196 				alloclen += rt->u.dst.trailer_len;
1197 
1198 			/*
1199 			 * We just reserve space for fragment header.
1200 			 * Note: this may be overallocation if the message
1201 			 * (without MSG_MORE) fits into the MTU.
1202 			 */
1203 			alloclen += sizeof(struct frag_hdr);
1204 
1205 			if (transhdrlen) {
1206 				skb = sock_alloc_send_skb(sk,
1207 						alloclen + hh_len,
1208 						(flags & MSG_DONTWAIT), &err);
1209 			} else {
1210 				skb = NULL;
1211 				if (atomic_read(&sk->sk_wmem_alloc) <=
1212 				    2 * sk->sk_sndbuf)
1213 					skb = sock_wmalloc(sk,
1214 							   alloclen + hh_len, 1,
1215 							   sk->sk_allocation);
1216 				if (unlikely(skb == NULL))
1217 					err = -ENOBUFS;
1218 			}
1219 			if (skb == NULL)
1220 				goto error;
1221 			/*
1222 			 *	Fill in the control structures
1223 			 */
1224 			skb->ip_summed = csummode;
1225 			skb->csum = 0;
1226 			/* reserve for fragmentation */
1227 			skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
1228 
1229 			/*
1230 			 *	Find where to start putting bytes
1231 			 */
1232 			data = skb_put(skb, fraglen);
1233 			skb_set_network_header(skb, exthdrlen);
1234 			data += fragheaderlen;
1235 			skb->transport_header = (skb->network_header +
1236 						 fragheaderlen);
1237 			if (fraggap) {
1238 				skb->csum = skb_copy_and_csum_bits(
1239 					skb_prev, maxfraglen,
1240 					data + transhdrlen, fraggap, 0);
1241 				skb_prev->csum = csum_sub(skb_prev->csum,
1242 							  skb->csum);
1243 				data += fraggap;
1244 				pskb_trim_unique(skb_prev, maxfraglen);
1245 			}
1246 			copy = datalen - transhdrlen - fraggap;
1247 			if (copy < 0) {
1248 				err = -EINVAL;
1249 				kfree_skb(skb);
1250 				goto error;
1251 			} else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1252 				err = -EFAULT;
1253 				kfree_skb(skb);
1254 				goto error;
1255 			}
1256 
1257 			offset += copy;
1258 			length -= datalen - fraggap;
1259 			transhdrlen = 0;
1260 			exthdrlen = 0;
1261 			csummode = CHECKSUM_NONE;
1262 
1263 			/*
1264 			 * Put the packet on the pending queue
1265 			 */
1266 			__skb_queue_tail(&sk->sk_write_queue, skb);
1267 			continue;
1268 		}
1269 
1270 		if (copy > length)
1271 			copy = length;
1272 
1273 		if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
1274 			unsigned int off;
1275 
1276 			off = skb->len;
1277 			if (getfrag(from, skb_put(skb, copy),
1278 						offset, copy, off, skb) < 0) {
1279 				__skb_trim(skb, off);
1280 				err = -EFAULT;
1281 				goto error;
1282 			}
1283 		} else {
1284 			int i = skb_shinfo(skb)->nr_frags;
1285 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1286 			struct page *page = sk->sk_sndmsg_page;
1287 			int off = sk->sk_sndmsg_off;
1288 			unsigned int left;
1289 
1290 			if (page && (left = PAGE_SIZE - off) > 0) {
1291 				if (copy >= left)
1292 					copy = left;
1293 				if (page != frag->page) {
1294 					if (i == MAX_SKB_FRAGS) {
1295 						err = -EMSGSIZE;
1296 						goto error;
1297 					}
1298 					get_page(page);
1299 					skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1300 					frag = &skb_shinfo(skb)->frags[i];
1301 				}
1302 			} else if(i < MAX_SKB_FRAGS) {
1303 				if (copy > PAGE_SIZE)
1304 					copy = PAGE_SIZE;
1305 				page = alloc_pages(sk->sk_allocation, 0);
1306 				if (page == NULL) {
1307 					err = -ENOMEM;
1308 					goto error;
1309 				}
1310 				sk->sk_sndmsg_page = page;
1311 				sk->sk_sndmsg_off = 0;
1312 
1313 				skb_fill_page_desc(skb, i, page, 0, 0);
1314 				frag = &skb_shinfo(skb)->frags[i];
1315 				skb->truesize += PAGE_SIZE;
1316 				atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
1317 			} else {
1318 				err = -EMSGSIZE;
1319 				goto error;
1320 			}
1321 			if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1322 				err = -EFAULT;
1323 				goto error;
1324 			}
1325 			sk->sk_sndmsg_off += copy;
1326 			frag->size += copy;
1327 			skb->len += copy;
1328 			skb->data_len += copy;
1329 		}
1330 		offset += copy;
1331 		length -= copy;
1332 	}
1333 	return 0;
1334 error:
1335 	inet->cork.length -= length;
1336 	IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1337 	return err;
1338 }
1339 
1340 int ip6_push_pending_frames(struct sock *sk)
1341 {
1342 	struct sk_buff *skb, *tmp_skb;
1343 	struct sk_buff **tail_skb;
1344 	struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1345 	struct inet_sock *inet = inet_sk(sk);
1346 	struct ipv6_pinfo *np = inet6_sk(sk);
1347 	struct ipv6hdr *hdr;
1348 	struct ipv6_txoptions *opt = np->cork.opt;
1349 	struct rt6_info *rt = np->cork.rt;
1350 	struct flowi *fl = &inet->cork.fl;
1351 	unsigned char proto = fl->proto;
1352 	int err = 0;
1353 
1354 	if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1355 		goto out;
1356 	tail_skb = &(skb_shinfo(skb)->frag_list);
1357 
1358 	/* move skb->data to ip header from ext header */
1359 	if (skb->data < skb_network_header(skb))
1360 		__skb_pull(skb, skb_network_offset(skb));
1361 	while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1362 		__skb_pull(tmp_skb, skb_network_header_len(skb));
1363 		*tail_skb = tmp_skb;
1364 		tail_skb = &(tmp_skb->next);
1365 		skb->len += tmp_skb->len;
1366 		skb->data_len += tmp_skb->len;
1367 		skb->truesize += tmp_skb->truesize;
1368 		__sock_put(tmp_skb->sk);
1369 		tmp_skb->destructor = NULL;
1370 		tmp_skb->sk = NULL;
1371 	}
1372 
1373 	ipv6_addr_copy(final_dst, &fl->fl6_dst);
1374 	__skb_pull(skb, skb_network_header_len(skb));
1375 	if (opt && opt->opt_flen)
1376 		ipv6_push_frag_opts(skb, opt, &proto);
1377 	if (opt && opt->opt_nflen)
1378 		ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1379 
1380 	skb_push(skb, sizeof(struct ipv6hdr));
1381 	skb_reset_network_header(skb);
1382 	hdr = ipv6_hdr(skb);
1383 
1384 	*(__be32*)hdr = fl->fl6_flowlabel |
1385 		     htonl(0x60000000 | ((int)np->cork.tclass << 20));
1386 
1387 	if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN)
1388 		hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
1389 	else
1390 		hdr->payload_len = 0;
1391 	hdr->hop_limit = np->cork.hop_limit;
1392 	hdr->nexthdr = proto;
1393 	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
1394 	ipv6_addr_copy(&hdr->daddr, final_dst);
1395 
1396 	skb->priority = sk->sk_priority;
1397 
1398 	skb->dst = dst_clone(&rt->u.dst);
1399 	IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
1400 	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output);
1401 	if (err) {
1402 		if (err > 0)
1403 			err = np->recverr ? net_xmit_errno(err) : 0;
1404 		if (err)
1405 			goto error;
1406 	}
1407 
1408 out:
1409 	inet->cork.flags &= ~IPCORK_OPT;
1410 	kfree(np->cork.opt);
1411 	np->cork.opt = NULL;
1412 	if (np->cork.rt) {
1413 		dst_release(&np->cork.rt->u.dst);
1414 		np->cork.rt = NULL;
1415 		inet->cork.flags &= ~IPCORK_ALLFRAG;
1416 	}
1417 	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1418 	return err;
1419 error:
1420 	goto out;
1421 }
1422 
1423 void ip6_flush_pending_frames(struct sock *sk)
1424 {
1425 	struct inet_sock *inet = inet_sk(sk);
1426 	struct ipv6_pinfo *np = inet6_sk(sk);
1427 	struct sk_buff *skb;
1428 
1429 	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1430 		IP6_INC_STATS(ip6_dst_idev(skb->dst),
1431 			      IPSTATS_MIB_OUTDISCARDS);
1432 		kfree_skb(skb);
1433 	}
1434 
1435 	inet->cork.flags &= ~IPCORK_OPT;
1436 
1437 	kfree(np->cork.opt);
1438 	np->cork.opt = NULL;
1439 	if (np->cork.rt) {
1440 		dst_release(&np->cork.rt->u.dst);
1441 		np->cork.rt = NULL;
1442 		inet->cork.flags &= ~IPCORK_ALLFRAG;
1443 	}
1444 	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1445 }
1446