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ipv6: always prefer rt6i_gateway if present
[deliverable/linux.git] / net / ipv6 / ip6_output.c
1 /*
2 * IPv6 output functions
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on linux/net/ipv4/ip_output.c
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Changes:
16 * A.N.Kuznetsov : airthmetics in fragmentation.
17 * extension headers are implemented.
18 * route changes now work.
19 * ip6_forward does not confuse sniffers.
20 * etc.
21 *
22 * H. von Brand : Added missing #include <linux/string.h>
23 * Imran Patel : frag id should be in NBO
24 * Kazunori MIYAZAWA @USAGI
25 * : add ip6_append_data and related functions
26 * for datagram xmit
27 */
28
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/string.h>
32 #include <linux/socket.h>
33 #include <linux/net.h>
34 #include <linux/netdevice.h>
35 #include <linux/if_arp.h>
36 #include <linux/in6.h>
37 #include <linux/tcp.h>
38 #include <linux/route.h>
39 #include <linux/module.h>
40 #include <linux/slab.h>
41
42 #include <linux/netfilter.h>
43 #include <linux/netfilter_ipv6.h>
44
45 #include <net/sock.h>
46 #include <net/snmp.h>
47
48 #include <net/ipv6.h>
49 #include <net/ndisc.h>
50 #include <net/protocol.h>
51 #include <net/ip6_route.h>
52 #include <net/addrconf.h>
53 #include <net/rawv6.h>
54 #include <net/icmp.h>
55 #include <net/xfrm.h>
56 #include <net/checksum.h>
57 #include <linux/mroute6.h>
58
59 static int ip6_finish_output2(struct sk_buff *skb)
60 {
61 struct dst_entry *dst = skb_dst(skb);
62 struct net_device *dev = dst->dev;
63 struct neighbour *neigh;
64 struct in6_addr *nexthop;
65 int ret;
66
67 skb->protocol = htons(ETH_P_IPV6);
68 skb->dev = dev;
69
70 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
71 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
72
73 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&
74 ((mroute6_socket(dev_net(dev), skb) &&
75 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
76 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
77 &ipv6_hdr(skb)->saddr))) {
78 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
79
80 /* Do not check for IFF_ALLMULTI; multicast routing
81 is not supported in any case.
82 */
83 if (newskb)
84 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
85 newskb, NULL, newskb->dev,
86 dev_loopback_xmit);
87
88 if (ipv6_hdr(skb)->hop_limit == 0) {
89 IP6_INC_STATS(dev_net(dev), idev,
90 IPSTATS_MIB_OUTDISCARDS);
91 kfree_skb(skb);
92 return 0;
93 }
94 }
95
96 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST,
97 skb->len);
98
99 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
100 IPV6_ADDR_SCOPE_NODELOCAL &&
101 !(dev->flags & IFF_LOOPBACK)) {
102 kfree_skb(skb);
103 return 0;
104 }
105 }
106
107 rcu_read_lock_bh();
108 nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
109 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
110 if (unlikely(!neigh))
111 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
112 if (!IS_ERR(neigh)) {
113 ret = dst_neigh_output(dst, neigh, skb);
114 rcu_read_unlock_bh();
115 return ret;
116 }
117 rcu_read_unlock_bh();
118
119 IP6_INC_STATS_BH(dev_net(dst->dev),
120 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
121 kfree_skb(skb);
122 return -EINVAL;
123 }
124
125 static int ip6_finish_output(struct sk_buff *skb)
126 {
127 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
128 dst_allfrag(skb_dst(skb)))
129 return ip6_fragment(skb, ip6_finish_output2);
130 else
131 return ip6_finish_output2(skb);
132 }
133
134 int ip6_output(struct sk_buff *skb)
135 {
136 struct net_device *dev = skb_dst(skb)->dev;
137 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
138 if (unlikely(idev->cnf.disable_ipv6)) {
139 IP6_INC_STATS(dev_net(dev), idev,
140 IPSTATS_MIB_OUTDISCARDS);
141 kfree_skb(skb);
142 return 0;
143 }
144
145 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
146 ip6_finish_output,
147 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
148 }
149
150 /*
151 * xmit an sk_buff (used by TCP, SCTP and DCCP)
152 */
153
154 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
155 struct ipv6_txoptions *opt, int tclass)
156 {
157 struct net *net = sock_net(sk);
158 struct ipv6_pinfo *np = inet6_sk(sk);
159 struct in6_addr *first_hop = &fl6->daddr;
160 struct dst_entry *dst = skb_dst(skb);
161 struct ipv6hdr *hdr;
162 u8 proto = fl6->flowi6_proto;
163 int seg_len = skb->len;
164 int hlimit = -1;
165 u32 mtu;
166
167 if (opt) {
168 unsigned int head_room;
169
170 /* First: exthdrs may take lots of space (~8K for now)
171 MAX_HEADER is not enough.
172 */
173 head_room = opt->opt_nflen + opt->opt_flen;
174 seg_len += head_room;
175 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
176
177 if (skb_headroom(skb) < head_room) {
178 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
179 if (skb2 == NULL) {
180 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
181 IPSTATS_MIB_OUTDISCARDS);
182 kfree_skb(skb);
183 return -ENOBUFS;
184 }
185 consume_skb(skb);
186 skb = skb2;
187 skb_set_owner_w(skb, sk);
188 }
189 if (opt->opt_flen)
190 ipv6_push_frag_opts(skb, opt, &proto);
191 if (opt->opt_nflen)
192 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
193 }
194
195 skb_push(skb, sizeof(struct ipv6hdr));
196 skb_reset_network_header(skb);
197 hdr = ipv6_hdr(skb);
198
199 /*
200 * Fill in the IPv6 header
201 */
202 if (np)
203 hlimit = np->hop_limit;
204 if (hlimit < 0)
205 hlimit = ip6_dst_hoplimit(dst);
206
207 ip6_flow_hdr(hdr, tclass, fl6->flowlabel);
208
209 hdr->payload_len = htons(seg_len);
210 hdr->nexthdr = proto;
211 hdr->hop_limit = hlimit;
212
213 hdr->saddr = fl6->saddr;
214 hdr->daddr = *first_hop;
215
216 skb->protocol = htons(ETH_P_IPV6);
217 skb->priority = sk->sk_priority;
218 skb->mark = sk->sk_mark;
219
220 mtu = dst_mtu(dst);
221 if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
222 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
223 IPSTATS_MIB_OUT, skb->len);
224 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
225 dst->dev, dst_output);
226 }
227
228 skb->dev = dst->dev;
229 ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
230 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
231 kfree_skb(skb);
232 return -EMSGSIZE;
233 }
234
235 EXPORT_SYMBOL(ip6_xmit);
236
237 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
238 {
239 struct ip6_ra_chain *ra;
240 struct sock *last = NULL;
241
242 read_lock(&ip6_ra_lock);
243 for (ra = ip6_ra_chain; ra; ra = ra->next) {
244 struct sock *sk = ra->sk;
245 if (sk && ra->sel == sel &&
246 (!sk->sk_bound_dev_if ||
247 sk->sk_bound_dev_if == skb->dev->ifindex)) {
248 if (last) {
249 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
250 if (skb2)
251 rawv6_rcv(last, skb2);
252 }
253 last = sk;
254 }
255 }
256
257 if (last) {
258 rawv6_rcv(last, skb);
259 read_unlock(&ip6_ra_lock);
260 return 1;
261 }
262 read_unlock(&ip6_ra_lock);
263 return 0;
264 }
265
266 static int ip6_forward_proxy_check(struct sk_buff *skb)
267 {
268 struct ipv6hdr *hdr = ipv6_hdr(skb);
269 u8 nexthdr = hdr->nexthdr;
270 __be16 frag_off;
271 int offset;
272
273 if (ipv6_ext_hdr(nexthdr)) {
274 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
275 if (offset < 0)
276 return 0;
277 } else
278 offset = sizeof(struct ipv6hdr);
279
280 if (nexthdr == IPPROTO_ICMPV6) {
281 struct icmp6hdr *icmp6;
282
283 if (!pskb_may_pull(skb, (skb_network_header(skb) +
284 offset + 1 - skb->data)))
285 return 0;
286
287 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
288
289 switch (icmp6->icmp6_type) {
290 case NDISC_ROUTER_SOLICITATION:
291 case NDISC_ROUTER_ADVERTISEMENT:
292 case NDISC_NEIGHBOUR_SOLICITATION:
293 case NDISC_NEIGHBOUR_ADVERTISEMENT:
294 case NDISC_REDIRECT:
295 /* For reaction involving unicast neighbor discovery
296 * message destined to the proxied address, pass it to
297 * input function.
298 */
299 return 1;
300 default:
301 break;
302 }
303 }
304
305 /*
306 * The proxying router can't forward traffic sent to a link-local
307 * address, so signal the sender and discard the packet. This
308 * behavior is clarified by the MIPv6 specification.
309 */
310 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
311 dst_link_failure(skb);
312 return -1;
313 }
314
315 return 0;
316 }
317
318 static inline int ip6_forward_finish(struct sk_buff *skb)
319 {
320 return dst_output(skb);
321 }
322
323 int ip6_forward(struct sk_buff *skb)
324 {
325 struct dst_entry *dst = skb_dst(skb);
326 struct ipv6hdr *hdr = ipv6_hdr(skb);
327 struct inet6_skb_parm *opt = IP6CB(skb);
328 struct net *net = dev_net(dst->dev);
329 u32 mtu;
330
331 if (net->ipv6.devconf_all->forwarding == 0)
332 goto error;
333
334 if (skb_warn_if_lro(skb))
335 goto drop;
336
337 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
338 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
339 goto drop;
340 }
341
342 if (skb->pkt_type != PACKET_HOST)
343 goto drop;
344
345 skb_forward_csum(skb);
346
347 /*
348 * We DO NOT make any processing on
349 * RA packets, pushing them to user level AS IS
350 * without ane WARRANTY that application will be able
351 * to interpret them. The reason is that we
352 * cannot make anything clever here.
353 *
354 * We are not end-node, so that if packet contains
355 * AH/ESP, we cannot make anything.
356 * Defragmentation also would be mistake, RA packets
357 * cannot be fragmented, because there is no warranty
358 * that different fragments will go along one path. --ANK
359 */
360 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
361 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
362 return 0;
363 }
364
365 /*
366 * check and decrement ttl
367 */
368 if (hdr->hop_limit <= 1) {
369 /* Force OUTPUT device used as source address */
370 skb->dev = dst->dev;
371 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
372 IP6_INC_STATS_BH(net,
373 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
374
375 kfree_skb(skb);
376 return -ETIMEDOUT;
377 }
378
379 /* XXX: idev->cnf.proxy_ndp? */
380 if (net->ipv6.devconf_all->proxy_ndp &&
381 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
382 int proxied = ip6_forward_proxy_check(skb);
383 if (proxied > 0)
384 return ip6_input(skb);
385 else if (proxied < 0) {
386 IP6_INC_STATS(net, ip6_dst_idev(dst),
387 IPSTATS_MIB_INDISCARDS);
388 goto drop;
389 }
390 }
391
392 if (!xfrm6_route_forward(skb)) {
393 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
394 goto drop;
395 }
396 dst = skb_dst(skb);
397
398 /* IPv6 specs say nothing about it, but it is clear that we cannot
399 send redirects to source routed frames.
400 We don't send redirects to frames decapsulated from IPsec.
401 */
402 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
403 struct in6_addr *target = NULL;
404 struct inet_peer *peer;
405 struct rt6_info *rt;
406
407 /*
408 * incoming and outgoing devices are the same
409 * send a redirect.
410 */
411
412 rt = (struct rt6_info *) dst;
413 if (rt->rt6i_flags & RTF_GATEWAY)
414 target = &rt->rt6i_gateway;
415 else
416 target = &hdr->daddr;
417
418 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
419
420 /* Limit redirects both by destination (here)
421 and by source (inside ndisc_send_redirect)
422 */
423 if (inet_peer_xrlim_allow(peer, 1*HZ))
424 ndisc_send_redirect(skb, target);
425 if (peer)
426 inet_putpeer(peer);
427 } else {
428 int addrtype = ipv6_addr_type(&hdr->saddr);
429
430 /* This check is security critical. */
431 if (addrtype == IPV6_ADDR_ANY ||
432 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
433 goto error;
434 if (addrtype & IPV6_ADDR_LINKLOCAL) {
435 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
436 ICMPV6_NOT_NEIGHBOUR, 0);
437 goto error;
438 }
439 }
440
441 mtu = dst_mtu(dst);
442 if (mtu < IPV6_MIN_MTU)
443 mtu = IPV6_MIN_MTU;
444
445 if ((!skb->local_df && skb->len > mtu && !skb_is_gso(skb)) ||
446 (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)) {
447 /* Again, force OUTPUT device used as source address */
448 skb->dev = dst->dev;
449 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
450 IP6_INC_STATS_BH(net,
451 ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
452 IP6_INC_STATS_BH(net,
453 ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
454 kfree_skb(skb);
455 return -EMSGSIZE;
456 }
457
458 if (skb_cow(skb, dst->dev->hard_header_len)) {
459 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
460 goto drop;
461 }
462
463 hdr = ipv6_hdr(skb);
464
465 /* Mangling hops number delayed to point after skb COW */
466
467 hdr->hop_limit--;
468
469 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
470 IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
471 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
472 ip6_forward_finish);
473
474 error:
475 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
476 drop:
477 kfree_skb(skb);
478 return -EINVAL;
479 }
480
481 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
482 {
483 to->pkt_type = from->pkt_type;
484 to->priority = from->priority;
485 to->protocol = from->protocol;
486 skb_dst_drop(to);
487 skb_dst_set(to, dst_clone(skb_dst(from)));
488 to->dev = from->dev;
489 to->mark = from->mark;
490
491 #ifdef CONFIG_NET_SCHED
492 to->tc_index = from->tc_index;
493 #endif
494 nf_copy(to, from);
495 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
496 to->nf_trace = from->nf_trace;
497 #endif
498 skb_copy_secmark(to, from);
499 }
500
501 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
502 {
503 struct sk_buff *frag;
504 struct rt6_info *rt = (struct rt6_info*)skb_dst(skb);
505 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
506 struct ipv6hdr *tmp_hdr;
507 struct frag_hdr *fh;
508 unsigned int mtu, hlen, left, len;
509 int hroom, troom;
510 __be32 frag_id = 0;
511 int ptr, offset = 0, err=0;
512 u8 *prevhdr, nexthdr = 0;
513 struct net *net = dev_net(skb_dst(skb)->dev);
514
515 hlen = ip6_find_1stfragopt(skb, &prevhdr);
516 nexthdr = *prevhdr;
517
518 mtu = ip6_skb_dst_mtu(skb);
519
520 /* We must not fragment if the socket is set to force MTU discovery
521 * or if the skb it not generated by a local socket.
522 */
523 if (unlikely(!skb->local_df && skb->len > mtu) ||
524 (IP6CB(skb)->frag_max_size &&
525 IP6CB(skb)->frag_max_size > mtu)) {
526 if (skb->sk && dst_allfrag(skb_dst(skb)))
527 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
528
529 skb->dev = skb_dst(skb)->dev;
530 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
531 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
532 IPSTATS_MIB_FRAGFAILS);
533 kfree_skb(skb);
534 return -EMSGSIZE;
535 }
536
537 if (np && np->frag_size < mtu) {
538 if (np->frag_size)
539 mtu = np->frag_size;
540 }
541 mtu -= hlen + sizeof(struct frag_hdr);
542
543 if (skb_has_frag_list(skb)) {
544 int first_len = skb_pagelen(skb);
545 struct sk_buff *frag2;
546
547 if (first_len - hlen > mtu ||
548 ((first_len - hlen) & 7) ||
549 skb_cloned(skb))
550 goto slow_path;
551
552 skb_walk_frags(skb, frag) {
553 /* Correct geometry. */
554 if (frag->len > mtu ||
555 ((frag->len & 7) && frag->next) ||
556 skb_headroom(frag) < hlen)
557 goto slow_path_clean;
558
559 /* Partially cloned skb? */
560 if (skb_shared(frag))
561 goto slow_path_clean;
562
563 BUG_ON(frag->sk);
564 if (skb->sk) {
565 frag->sk = skb->sk;
566 frag->destructor = sock_wfree;
567 }
568 skb->truesize -= frag->truesize;
569 }
570
571 err = 0;
572 offset = 0;
573 frag = skb_shinfo(skb)->frag_list;
574 skb_frag_list_init(skb);
575 /* BUILD HEADER */
576
577 *prevhdr = NEXTHDR_FRAGMENT;
578 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
579 if (!tmp_hdr) {
580 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
581 IPSTATS_MIB_FRAGFAILS);
582 return -ENOMEM;
583 }
584
585 __skb_pull(skb, hlen);
586 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
587 __skb_push(skb, hlen);
588 skb_reset_network_header(skb);
589 memcpy(skb_network_header(skb), tmp_hdr, hlen);
590
591 ipv6_select_ident(fh, rt);
592 fh->nexthdr = nexthdr;
593 fh->reserved = 0;
594 fh->frag_off = htons(IP6_MF);
595 frag_id = fh->identification;
596
597 first_len = skb_pagelen(skb);
598 skb->data_len = first_len - skb_headlen(skb);
599 skb->len = first_len;
600 ipv6_hdr(skb)->payload_len = htons(first_len -
601 sizeof(struct ipv6hdr));
602
603 dst_hold(&rt->dst);
604
605 for (;;) {
606 /* Prepare header of the next frame,
607 * before previous one went down. */
608 if (frag) {
609 frag->ip_summed = CHECKSUM_NONE;
610 skb_reset_transport_header(frag);
611 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
612 __skb_push(frag, hlen);
613 skb_reset_network_header(frag);
614 memcpy(skb_network_header(frag), tmp_hdr,
615 hlen);
616 offset += skb->len - hlen - sizeof(struct frag_hdr);
617 fh->nexthdr = nexthdr;
618 fh->reserved = 0;
619 fh->frag_off = htons(offset);
620 if (frag->next != NULL)
621 fh->frag_off |= htons(IP6_MF);
622 fh->identification = frag_id;
623 ipv6_hdr(frag)->payload_len =
624 htons(frag->len -
625 sizeof(struct ipv6hdr));
626 ip6_copy_metadata(frag, skb);
627 }
628
629 err = output(skb);
630 if(!err)
631 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
632 IPSTATS_MIB_FRAGCREATES);
633
634 if (err || !frag)
635 break;
636
637 skb = frag;
638 frag = skb->next;
639 skb->next = NULL;
640 }
641
642 kfree(tmp_hdr);
643
644 if (err == 0) {
645 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
646 IPSTATS_MIB_FRAGOKS);
647 ip6_rt_put(rt);
648 return 0;
649 }
650
651 while (frag) {
652 skb = frag->next;
653 kfree_skb(frag);
654 frag = skb;
655 }
656
657 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
658 IPSTATS_MIB_FRAGFAILS);
659 ip6_rt_put(rt);
660 return err;
661
662 slow_path_clean:
663 skb_walk_frags(skb, frag2) {
664 if (frag2 == frag)
665 break;
666 frag2->sk = NULL;
667 frag2->destructor = NULL;
668 skb->truesize += frag2->truesize;
669 }
670 }
671
672 slow_path:
673 if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
674 skb_checksum_help(skb))
675 goto fail;
676
677 left = skb->len - hlen; /* Space per frame */
678 ptr = hlen; /* Where to start from */
679
680 /*
681 * Fragment the datagram.
682 */
683
684 *prevhdr = NEXTHDR_FRAGMENT;
685 hroom = LL_RESERVED_SPACE(rt->dst.dev);
686 troom = rt->dst.dev->needed_tailroom;
687
688 /*
689 * Keep copying data until we run out.
690 */
691 while(left > 0) {
692 len = left;
693 /* IF: it doesn't fit, use 'mtu' - the data space left */
694 if (len > mtu)
695 len = mtu;
696 /* IF: we are not sending up to and including the packet end
697 then align the next start on an eight byte boundary */
698 if (len < left) {
699 len &= ~7;
700 }
701 /*
702 * Allocate buffer.
703 */
704
705 if ((frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
706 hroom + troom, GFP_ATOMIC)) == NULL) {
707 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
708 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
709 IPSTATS_MIB_FRAGFAILS);
710 err = -ENOMEM;
711 goto fail;
712 }
713
714 /*
715 * Set up data on packet
716 */
717
718 ip6_copy_metadata(frag, skb);
719 skb_reserve(frag, hroom);
720 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
721 skb_reset_network_header(frag);
722 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
723 frag->transport_header = (frag->network_header + hlen +
724 sizeof(struct frag_hdr));
725
726 /*
727 * Charge the memory for the fragment to any owner
728 * it might possess
729 */
730 if (skb->sk)
731 skb_set_owner_w(frag, skb->sk);
732
733 /*
734 * Copy the packet header into the new buffer.
735 */
736 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
737
738 /*
739 * Build fragment header.
740 */
741 fh->nexthdr = nexthdr;
742 fh->reserved = 0;
743 if (!frag_id) {
744 ipv6_select_ident(fh, rt);
745 frag_id = fh->identification;
746 } else
747 fh->identification = frag_id;
748
749 /*
750 * Copy a block of the IP datagram.
751 */
752 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
753 BUG();
754 left -= len;
755
756 fh->frag_off = htons(offset);
757 if (left > 0)
758 fh->frag_off |= htons(IP6_MF);
759 ipv6_hdr(frag)->payload_len = htons(frag->len -
760 sizeof(struct ipv6hdr));
761
762 ptr += len;
763 offset += len;
764
765 /*
766 * Put this fragment into the sending queue.
767 */
768 err = output(frag);
769 if (err)
770 goto fail;
771
772 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
773 IPSTATS_MIB_FRAGCREATES);
774 }
775 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
776 IPSTATS_MIB_FRAGOKS);
777 consume_skb(skb);
778 return err;
779
780 fail:
781 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
782 IPSTATS_MIB_FRAGFAILS);
783 kfree_skb(skb);
784 return err;
785 }
786
787 static inline int ip6_rt_check(const struct rt6key *rt_key,
788 const struct in6_addr *fl_addr,
789 const struct in6_addr *addr_cache)
790 {
791 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
792 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
793 }
794
795 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
796 struct dst_entry *dst,
797 const struct flowi6 *fl6)
798 {
799 struct ipv6_pinfo *np = inet6_sk(sk);
800 struct rt6_info *rt;
801
802 if (!dst)
803 goto out;
804
805 if (dst->ops->family != AF_INET6) {
806 dst_release(dst);
807 return NULL;
808 }
809
810 rt = (struct rt6_info *)dst;
811 /* Yes, checking route validity in not connected
812 * case is not very simple. Take into account,
813 * that we do not support routing by source, TOS,
814 * and MSG_DONTROUTE --ANK (980726)
815 *
816 * 1. ip6_rt_check(): If route was host route,
817 * check that cached destination is current.
818 * If it is network route, we still may
819 * check its validity using saved pointer
820 * to the last used address: daddr_cache.
821 * We do not want to save whole address now,
822 * (because main consumer of this service
823 * is tcp, which has not this problem),
824 * so that the last trick works only on connected
825 * sockets.
826 * 2. oif also should be the same.
827 */
828 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
829 #ifdef CONFIG_IPV6_SUBTREES
830 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
831 #endif
832 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
833 dst_release(dst);
834 dst = NULL;
835 }
836
837 out:
838 return dst;
839 }
840
841 static int ip6_dst_lookup_tail(struct sock *sk,
842 struct dst_entry **dst, struct flowi6 *fl6)
843 {
844 struct net *net = sock_net(sk);
845 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
846 struct neighbour *n;
847 struct rt6_info *rt;
848 #endif
849 int err;
850
851 if (*dst == NULL)
852 *dst = ip6_route_output(net, sk, fl6);
853
854 if ((err = (*dst)->error))
855 goto out_err_release;
856
857 if (ipv6_addr_any(&fl6->saddr)) {
858 struct rt6_info *rt = (struct rt6_info *) *dst;
859 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
860 sk ? inet6_sk(sk)->srcprefs : 0,
861 &fl6->saddr);
862 if (err)
863 goto out_err_release;
864 }
865
866 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
867 /*
868 * Here if the dst entry we've looked up
869 * has a neighbour entry that is in the INCOMPLETE
870 * state and the src address from the flow is
871 * marked as OPTIMISTIC, we release the found
872 * dst entry and replace it instead with the
873 * dst entry of the nexthop router
874 */
875 rt = (struct rt6_info *) *dst;
876 rcu_read_lock_bh();
877 n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt, &fl6->daddr));
878 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
879 rcu_read_unlock_bh();
880
881 if (err) {
882 struct inet6_ifaddr *ifp;
883 struct flowi6 fl_gw6;
884 int redirect;
885
886 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
887 (*dst)->dev, 1);
888
889 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
890 if (ifp)
891 in6_ifa_put(ifp);
892
893 if (redirect) {
894 /*
895 * We need to get the dst entry for the
896 * default router instead
897 */
898 dst_release(*dst);
899 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
900 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
901 *dst = ip6_route_output(net, sk, &fl_gw6);
902 if ((err = (*dst)->error))
903 goto out_err_release;
904 }
905 }
906 #endif
907
908 return 0;
909
910 out_err_release:
911 if (err == -ENETUNREACH)
912 IP6_INC_STATS_BH(net, NULL, IPSTATS_MIB_OUTNOROUTES);
913 dst_release(*dst);
914 *dst = NULL;
915 return err;
916 }
917
918 /**
919 * ip6_dst_lookup - perform route lookup on flow
920 * @sk: socket which provides route info
921 * @dst: pointer to dst_entry * for result
922 * @fl6: flow to lookup
923 *
924 * This function performs a route lookup on the given flow.
925 *
926 * It returns zero on success, or a standard errno code on error.
927 */
928 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
929 {
930 *dst = NULL;
931 return ip6_dst_lookup_tail(sk, dst, fl6);
932 }
933 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
934
935 /**
936 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
937 * @sk: socket which provides route info
938 * @fl6: flow to lookup
939 * @final_dst: final destination address for ipsec lookup
940 * @can_sleep: we are in a sleepable context
941 *
942 * This function performs a route lookup on the given flow.
943 *
944 * It returns a valid dst pointer on success, or a pointer encoded
945 * error code.
946 */
947 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
948 const struct in6_addr *final_dst,
949 bool can_sleep)
950 {
951 struct dst_entry *dst = NULL;
952 int err;
953
954 err = ip6_dst_lookup_tail(sk, &dst, fl6);
955 if (err)
956 return ERR_PTR(err);
957 if (final_dst)
958 fl6->daddr = *final_dst;
959 if (can_sleep)
960 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
961
962 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
963 }
964 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
965
966 /**
967 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
968 * @sk: socket which provides the dst cache and route info
969 * @fl6: flow to lookup
970 * @final_dst: final destination address for ipsec lookup
971 * @can_sleep: we are in a sleepable context
972 *
973 * This function performs a route lookup on the given flow with the
974 * possibility of using the cached route in the socket if it is valid.
975 * It will take the socket dst lock when operating on the dst cache.
976 * As a result, this function can only be used in process context.
977 *
978 * It returns a valid dst pointer on success, or a pointer encoded
979 * error code.
980 */
981 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
982 const struct in6_addr *final_dst,
983 bool can_sleep)
984 {
985 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
986 int err;
987
988 dst = ip6_sk_dst_check(sk, dst, fl6);
989
990 err = ip6_dst_lookup_tail(sk, &dst, fl6);
991 if (err)
992 return ERR_PTR(err);
993 if (final_dst)
994 fl6->daddr = *final_dst;
995 if (can_sleep)
996 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
997
998 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
999 }
1000 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1001
1002 static inline int ip6_ufo_append_data(struct sock *sk,
1003 int getfrag(void *from, char *to, int offset, int len,
1004 int odd, struct sk_buff *skb),
1005 void *from, int length, int hh_len, int fragheaderlen,
1006 int transhdrlen, int mtu,unsigned int flags,
1007 struct rt6_info *rt)
1008
1009 {
1010 struct sk_buff *skb;
1011 struct frag_hdr fhdr;
1012 int err;
1013
1014 /* There is support for UDP large send offload by network
1015 * device, so create one single skb packet containing complete
1016 * udp datagram
1017 */
1018 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1019 skb = sock_alloc_send_skb(sk,
1020 hh_len + fragheaderlen + transhdrlen + 20,
1021 (flags & MSG_DONTWAIT), &err);
1022 if (skb == NULL)
1023 return err;
1024
1025 /* reserve space for Hardware header */
1026 skb_reserve(skb, hh_len);
1027
1028 /* create space for UDP/IP header */
1029 skb_put(skb,fragheaderlen + transhdrlen);
1030
1031 /* initialize network header pointer */
1032 skb_reset_network_header(skb);
1033
1034 /* initialize protocol header pointer */
1035 skb->transport_header = skb->network_header + fragheaderlen;
1036
1037 skb->protocol = htons(ETH_P_IPV6);
1038 skb->csum = 0;
1039
1040 __skb_queue_tail(&sk->sk_write_queue, skb);
1041 } else if (skb_is_gso(skb)) {
1042 goto append;
1043 }
1044
1045 skb->ip_summed = CHECKSUM_PARTIAL;
1046 /* Specify the length of each IPv6 datagram fragment.
1047 * It has to be a multiple of 8.
1048 */
1049 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1050 sizeof(struct frag_hdr)) & ~7;
1051 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1052 ipv6_select_ident(&fhdr, rt);
1053 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1054
1055 append:
1056 return skb_append_datato_frags(sk, skb, getfrag, from,
1057 (length - transhdrlen));
1058 }
1059
1060 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1061 gfp_t gfp)
1062 {
1063 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1064 }
1065
1066 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1067 gfp_t gfp)
1068 {
1069 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1070 }
1071
1072 static void ip6_append_data_mtu(unsigned int *mtu,
1073 int *maxfraglen,
1074 unsigned int fragheaderlen,
1075 struct sk_buff *skb,
1076 struct rt6_info *rt,
1077 bool pmtuprobe)
1078 {
1079 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1080 if (skb == NULL) {
1081 /* first fragment, reserve header_len */
1082 *mtu = *mtu - rt->dst.header_len;
1083
1084 } else {
1085 /*
1086 * this fragment is not first, the headers
1087 * space is regarded as data space.
1088 */
1089 *mtu = min(*mtu, pmtuprobe ?
1090 rt->dst.dev->mtu :
1091 dst_mtu(rt->dst.path));
1092 }
1093 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1094 + fragheaderlen - sizeof(struct frag_hdr);
1095 }
1096 }
1097
1098 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1099 int offset, int len, int odd, struct sk_buff *skb),
1100 void *from, int length, int transhdrlen,
1101 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1102 struct rt6_info *rt, unsigned int flags, int dontfrag)
1103 {
1104 struct inet_sock *inet = inet_sk(sk);
1105 struct ipv6_pinfo *np = inet6_sk(sk);
1106 struct inet_cork *cork;
1107 struct sk_buff *skb, *skb_prev = NULL;
1108 unsigned int maxfraglen, fragheaderlen, mtu;
1109 int exthdrlen;
1110 int dst_exthdrlen;
1111 int hh_len;
1112 int copy;
1113 int err;
1114 int offset = 0;
1115 __u8 tx_flags = 0;
1116
1117 if (flags&MSG_PROBE)
1118 return 0;
1119 cork = &inet->cork.base;
1120 if (skb_queue_empty(&sk->sk_write_queue)) {
1121 /*
1122 * setup for corking
1123 */
1124 if (opt) {
1125 if (WARN_ON(np->cork.opt))
1126 return -EINVAL;
1127
1128 np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1129 if (unlikely(np->cork.opt == NULL))
1130 return -ENOBUFS;
1131
1132 np->cork.opt->tot_len = opt->tot_len;
1133 np->cork.opt->opt_flen = opt->opt_flen;
1134 np->cork.opt->opt_nflen = opt->opt_nflen;
1135
1136 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1137 sk->sk_allocation);
1138 if (opt->dst0opt && !np->cork.opt->dst0opt)
1139 return -ENOBUFS;
1140
1141 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1142 sk->sk_allocation);
1143 if (opt->dst1opt && !np->cork.opt->dst1opt)
1144 return -ENOBUFS;
1145
1146 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1147 sk->sk_allocation);
1148 if (opt->hopopt && !np->cork.opt->hopopt)
1149 return -ENOBUFS;
1150
1151 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1152 sk->sk_allocation);
1153 if (opt->srcrt && !np->cork.opt->srcrt)
1154 return -ENOBUFS;
1155
1156 /* need source address above miyazawa*/
1157 }
1158 dst_hold(&rt->dst);
1159 cork->dst = &rt->dst;
1160 inet->cork.fl.u.ip6 = *fl6;
1161 np->cork.hop_limit = hlimit;
1162 np->cork.tclass = tclass;
1163 if (rt->dst.flags & DST_XFRM_TUNNEL)
1164 mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1165 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1166 else
1167 mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1168 rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1169 if (np->frag_size < mtu) {
1170 if (np->frag_size)
1171 mtu = np->frag_size;
1172 }
1173 cork->fragsize = mtu;
1174 if (dst_allfrag(rt->dst.path))
1175 cork->flags |= IPCORK_ALLFRAG;
1176 cork->length = 0;
1177 exthdrlen = (opt ? opt->opt_flen : 0);
1178 length += exthdrlen;
1179 transhdrlen += exthdrlen;
1180 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1181 } else {
1182 rt = (struct rt6_info *)cork->dst;
1183 fl6 = &inet->cork.fl.u.ip6;
1184 opt = np->cork.opt;
1185 transhdrlen = 0;
1186 exthdrlen = 0;
1187 dst_exthdrlen = 0;
1188 mtu = cork->fragsize;
1189 }
1190
1191 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1192
1193 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1194 (opt ? opt->opt_nflen : 0);
1195 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1196
1197 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1198 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1199 ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen);
1200 return -EMSGSIZE;
1201 }
1202 }
1203
1204 /* For UDP, check if TX timestamp is enabled */
1205 if (sk->sk_type == SOCK_DGRAM)
1206 sock_tx_timestamp(sk, &tx_flags);
1207
1208 /*
1209 * Let's try using as much space as possible.
1210 * Use MTU if total length of the message fits into the MTU.
1211 * Otherwise, we need to reserve fragment header and
1212 * fragment alignment (= 8-15 octects, in total).
1213 *
1214 * Note that we may need to "move" the data from the tail of
1215 * of the buffer to the new fragment when we split
1216 * the message.
1217 *
1218 * FIXME: It may be fragmented into multiple chunks
1219 * at once if non-fragmentable extension headers
1220 * are too large.
1221 * --yoshfuji
1222 */
1223
1224 if ((length > mtu) && dontfrag && (sk->sk_protocol == IPPROTO_UDP ||
1225 sk->sk_protocol == IPPROTO_RAW)) {
1226 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
1227 return -EMSGSIZE;
1228 }
1229
1230 skb = skb_peek_tail(&sk->sk_write_queue);
1231 cork->length += length;
1232 if (((length > mtu) ||
1233 (skb && skb_is_gso(skb))) &&
1234 (sk->sk_protocol == IPPROTO_UDP) &&
1235 (rt->dst.dev->features & NETIF_F_UFO)) {
1236 err = ip6_ufo_append_data(sk, getfrag, from, length,
1237 hh_len, fragheaderlen,
1238 transhdrlen, mtu, flags, rt);
1239 if (err)
1240 goto error;
1241 return 0;
1242 }
1243
1244 if (!skb)
1245 goto alloc_new_skb;
1246
1247 while (length > 0) {
1248 /* Check if the remaining data fits into current packet. */
1249 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1250 if (copy < length)
1251 copy = maxfraglen - skb->len;
1252
1253 if (copy <= 0) {
1254 char *data;
1255 unsigned int datalen;
1256 unsigned int fraglen;
1257 unsigned int fraggap;
1258 unsigned int alloclen;
1259 alloc_new_skb:
1260 /* There's no room in the current skb */
1261 if (skb)
1262 fraggap = skb->len - maxfraglen;
1263 else
1264 fraggap = 0;
1265 /* update mtu and maxfraglen if necessary */
1266 if (skb == NULL || skb_prev == NULL)
1267 ip6_append_data_mtu(&mtu, &maxfraglen,
1268 fragheaderlen, skb, rt,
1269 np->pmtudisc ==
1270 IPV6_PMTUDISC_PROBE);
1271
1272 skb_prev = skb;
1273
1274 /*
1275 * If remaining data exceeds the mtu,
1276 * we know we need more fragment(s).
1277 */
1278 datalen = length + fraggap;
1279
1280 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1281 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1282 if ((flags & MSG_MORE) &&
1283 !(rt->dst.dev->features&NETIF_F_SG))
1284 alloclen = mtu;
1285 else
1286 alloclen = datalen + fragheaderlen;
1287
1288 alloclen += dst_exthdrlen;
1289
1290 if (datalen != length + fraggap) {
1291 /*
1292 * this is not the last fragment, the trailer
1293 * space is regarded as data space.
1294 */
1295 datalen += rt->dst.trailer_len;
1296 }
1297
1298 alloclen += rt->dst.trailer_len;
1299 fraglen = datalen + fragheaderlen;
1300
1301 /*
1302 * We just reserve space for fragment header.
1303 * Note: this may be overallocation if the message
1304 * (without MSG_MORE) fits into the MTU.
1305 */
1306 alloclen += sizeof(struct frag_hdr);
1307
1308 if (transhdrlen) {
1309 skb = sock_alloc_send_skb(sk,
1310 alloclen + hh_len,
1311 (flags & MSG_DONTWAIT), &err);
1312 } else {
1313 skb = NULL;
1314 if (atomic_read(&sk->sk_wmem_alloc) <=
1315 2 * sk->sk_sndbuf)
1316 skb = sock_wmalloc(sk,
1317 alloclen + hh_len, 1,
1318 sk->sk_allocation);
1319 if (unlikely(skb == NULL))
1320 err = -ENOBUFS;
1321 else {
1322 /* Only the initial fragment
1323 * is time stamped.
1324 */
1325 tx_flags = 0;
1326 }
1327 }
1328 if (skb == NULL)
1329 goto error;
1330 /*
1331 * Fill in the control structures
1332 */
1333 skb->protocol = htons(ETH_P_IPV6);
1334 skb->ip_summed = CHECKSUM_NONE;
1335 skb->csum = 0;
1336 /* reserve for fragmentation and ipsec header */
1337 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1338 dst_exthdrlen);
1339
1340 if (sk->sk_type == SOCK_DGRAM)
1341 skb_shinfo(skb)->tx_flags = tx_flags;
1342
1343 /*
1344 * Find where to start putting bytes
1345 */
1346 data = skb_put(skb, fraglen);
1347 skb_set_network_header(skb, exthdrlen);
1348 data += fragheaderlen;
1349 skb->transport_header = (skb->network_header +
1350 fragheaderlen);
1351 if (fraggap) {
1352 skb->csum = skb_copy_and_csum_bits(
1353 skb_prev, maxfraglen,
1354 data + transhdrlen, fraggap, 0);
1355 skb_prev->csum = csum_sub(skb_prev->csum,
1356 skb->csum);
1357 data += fraggap;
1358 pskb_trim_unique(skb_prev, maxfraglen);
1359 }
1360 copy = datalen - transhdrlen - fraggap;
1361
1362 if (copy < 0) {
1363 err = -EINVAL;
1364 kfree_skb(skb);
1365 goto error;
1366 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1367 err = -EFAULT;
1368 kfree_skb(skb);
1369 goto error;
1370 }
1371
1372 offset += copy;
1373 length -= datalen - fraggap;
1374 transhdrlen = 0;
1375 exthdrlen = 0;
1376 dst_exthdrlen = 0;
1377
1378 /*
1379 * Put the packet on the pending queue
1380 */
1381 __skb_queue_tail(&sk->sk_write_queue, skb);
1382 continue;
1383 }
1384
1385 if (copy > length)
1386 copy = length;
1387
1388 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1389 unsigned int off;
1390
1391 off = skb->len;
1392 if (getfrag(from, skb_put(skb, copy),
1393 offset, copy, off, skb) < 0) {
1394 __skb_trim(skb, off);
1395 err = -EFAULT;
1396 goto error;
1397 }
1398 } else {
1399 int i = skb_shinfo(skb)->nr_frags;
1400 struct page_frag *pfrag = sk_page_frag(sk);
1401
1402 err = -ENOMEM;
1403 if (!sk_page_frag_refill(sk, pfrag))
1404 goto error;
1405
1406 if (!skb_can_coalesce(skb, i, pfrag->page,
1407 pfrag->offset)) {
1408 err = -EMSGSIZE;
1409 if (i == MAX_SKB_FRAGS)
1410 goto error;
1411
1412 __skb_fill_page_desc(skb, i, pfrag->page,
1413 pfrag->offset, 0);
1414 skb_shinfo(skb)->nr_frags = ++i;
1415 get_page(pfrag->page);
1416 }
1417 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1418 if (getfrag(from,
1419 page_address(pfrag->page) + pfrag->offset,
1420 offset, copy, skb->len, skb) < 0)
1421 goto error_efault;
1422
1423 pfrag->offset += copy;
1424 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1425 skb->len += copy;
1426 skb->data_len += copy;
1427 skb->truesize += copy;
1428 atomic_add(copy, &sk->sk_wmem_alloc);
1429 }
1430 offset += copy;
1431 length -= copy;
1432 }
1433
1434 return 0;
1435
1436 error_efault:
1437 err = -EFAULT;
1438 error:
1439 cork->length -= length;
1440 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1441 return err;
1442 }
1443 EXPORT_SYMBOL_GPL(ip6_append_data);
1444
1445 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1446 {
1447 if (np->cork.opt) {
1448 kfree(np->cork.opt->dst0opt);
1449 kfree(np->cork.opt->dst1opt);
1450 kfree(np->cork.opt->hopopt);
1451 kfree(np->cork.opt->srcrt);
1452 kfree(np->cork.opt);
1453 np->cork.opt = NULL;
1454 }
1455
1456 if (inet->cork.base.dst) {
1457 dst_release(inet->cork.base.dst);
1458 inet->cork.base.dst = NULL;
1459 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1460 }
1461 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1462 }
1463
1464 int ip6_push_pending_frames(struct sock *sk)
1465 {
1466 struct sk_buff *skb, *tmp_skb;
1467 struct sk_buff **tail_skb;
1468 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1469 struct inet_sock *inet = inet_sk(sk);
1470 struct ipv6_pinfo *np = inet6_sk(sk);
1471 struct net *net = sock_net(sk);
1472 struct ipv6hdr *hdr;
1473 struct ipv6_txoptions *opt = np->cork.opt;
1474 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1475 struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1476 unsigned char proto = fl6->flowi6_proto;
1477 int err = 0;
1478
1479 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1480 goto out;
1481 tail_skb = &(skb_shinfo(skb)->frag_list);
1482
1483 /* move skb->data to ip header from ext header */
1484 if (skb->data < skb_network_header(skb))
1485 __skb_pull(skb, skb_network_offset(skb));
1486 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1487 __skb_pull(tmp_skb, skb_network_header_len(skb));
1488 *tail_skb = tmp_skb;
1489 tail_skb = &(tmp_skb->next);
1490 skb->len += tmp_skb->len;
1491 skb->data_len += tmp_skb->len;
1492 skb->truesize += tmp_skb->truesize;
1493 tmp_skb->destructor = NULL;
1494 tmp_skb->sk = NULL;
1495 }
1496
1497 /* Allow local fragmentation. */
1498 if (np->pmtudisc < IPV6_PMTUDISC_DO)
1499 skb->local_df = 1;
1500
1501 *final_dst = fl6->daddr;
1502 __skb_pull(skb, skb_network_header_len(skb));
1503 if (opt && opt->opt_flen)
1504 ipv6_push_frag_opts(skb, opt, &proto);
1505 if (opt && opt->opt_nflen)
1506 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1507
1508 skb_push(skb, sizeof(struct ipv6hdr));
1509 skb_reset_network_header(skb);
1510 hdr = ipv6_hdr(skb);
1511
1512 ip6_flow_hdr(hdr, np->cork.tclass, fl6->flowlabel);
1513 hdr->hop_limit = np->cork.hop_limit;
1514 hdr->nexthdr = proto;
1515 hdr->saddr = fl6->saddr;
1516 hdr->daddr = *final_dst;
1517
1518 skb->priority = sk->sk_priority;
1519 skb->mark = sk->sk_mark;
1520
1521 skb_dst_set(skb, dst_clone(&rt->dst));
1522 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1523 if (proto == IPPROTO_ICMPV6) {
1524 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1525
1526 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type);
1527 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
1528 }
1529
1530 err = ip6_local_out(skb);
1531 if (err) {
1532 if (err > 0)
1533 err = net_xmit_errno(err);
1534 if (err)
1535 goto error;
1536 }
1537
1538 out:
1539 ip6_cork_release(inet, np);
1540 return err;
1541 error:
1542 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1543 goto out;
1544 }
1545 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1546
1547 void ip6_flush_pending_frames(struct sock *sk)
1548 {
1549 struct sk_buff *skb;
1550
1551 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1552 if (skb_dst(skb))
1553 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1554 IPSTATS_MIB_OUTDISCARDS);
1555 kfree_skb(skb);
1556 }
1557
1558 ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1559 }
1560 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
Linux kernel - Deliverables
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