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ipv6: Select fragment id during UFO segmentation if not set.
[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);
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(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 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
130 return ip6_fragment(skb, ip6_finish_output2);
131 else
132 return ip6_finish_output2(skb);
133 }
134
135 int ip6_output(struct sock *sk, struct sk_buff *skb)
136 {
137 struct net_device *dev = skb_dst(skb)->dev;
138 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
139 if (unlikely(idev->cnf.disable_ipv6)) {
140 IP6_INC_STATS(dev_net(dev), idev,
141 IPSTATS_MIB_OUTDISCARDS);
142 kfree_skb(skb);
143 return 0;
144 }
145
146 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
147 ip6_finish_output,
148 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
149 }
150
151 /*
152 * xmit an sk_buff (used by TCP, SCTP and DCCP)
153 */
154
155 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
156 struct ipv6_txoptions *opt, int tclass)
157 {
158 struct net *net = sock_net(sk);
159 struct ipv6_pinfo *np = inet6_sk(sk);
160 struct in6_addr *first_hop = &fl6->daddr;
161 struct dst_entry *dst = skb_dst(skb);
162 struct ipv6hdr *hdr;
163 u8 proto = fl6->flowi6_proto;
164 int seg_len = skb->len;
165 int hlimit = -1;
166 u32 mtu;
167
168 if (opt) {
169 unsigned int head_room;
170
171 /* First: exthdrs may take lots of space (~8K for now)
172 MAX_HEADER is not enough.
173 */
174 head_room = opt->opt_nflen + opt->opt_flen;
175 seg_len += head_room;
176 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
177
178 if (skb_headroom(skb) < head_room) {
179 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
180 if (skb2 == NULL) {
181 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
182 IPSTATS_MIB_OUTDISCARDS);
183 kfree_skb(skb);
184 return -ENOBUFS;
185 }
186 consume_skb(skb);
187 skb = skb2;
188 skb_set_owner_w(skb, sk);
189 }
190 if (opt->opt_flen)
191 ipv6_push_frag_opts(skb, opt, &proto);
192 if (opt->opt_nflen)
193 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
194 }
195
196 skb_push(skb, sizeof(struct ipv6hdr));
197 skb_reset_network_header(skb);
198 hdr = ipv6_hdr(skb);
199
200 /*
201 * Fill in the IPv6 header
202 */
203 if (np)
204 hlimit = np->hop_limit;
205 if (hlimit < 0)
206 hlimit = ip6_dst_hoplimit(dst);
207
208 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
209 np->autoflowlabel));
210
211 hdr->payload_len = htons(seg_len);
212 hdr->nexthdr = proto;
213 hdr->hop_limit = hlimit;
214
215 hdr->saddr = fl6->saddr;
216 hdr->daddr = *first_hop;
217
218 skb->protocol = htons(ETH_P_IPV6);
219 skb->priority = sk->sk_priority;
220 skb->mark = sk->sk_mark;
221
222 mtu = dst_mtu(dst);
223 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
224 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
225 IPSTATS_MIB_OUT, skb->len);
226 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
227 dst->dev, dst_output);
228 }
229
230 skb->dev = dst->dev;
231 ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
232 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
233 kfree_skb(skb);
234 return -EMSGSIZE;
235 }
236 EXPORT_SYMBOL(ip6_xmit);
237
238 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
239 {
240 struct ip6_ra_chain *ra;
241 struct sock *last = NULL;
242
243 read_lock(&ip6_ra_lock);
244 for (ra = ip6_ra_chain; ra; ra = ra->next) {
245 struct sock *sk = ra->sk;
246 if (sk && ra->sel == sel &&
247 (!sk->sk_bound_dev_if ||
248 sk->sk_bound_dev_if == skb->dev->ifindex)) {
249 if (last) {
250 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
251 if (skb2)
252 rawv6_rcv(last, skb2);
253 }
254 last = sk;
255 }
256 }
257
258 if (last) {
259 rawv6_rcv(last, skb);
260 read_unlock(&ip6_ra_lock);
261 return 1;
262 }
263 read_unlock(&ip6_ra_lock);
264 return 0;
265 }
266
267 static int ip6_forward_proxy_check(struct sk_buff *skb)
268 {
269 struct ipv6hdr *hdr = ipv6_hdr(skb);
270 u8 nexthdr = hdr->nexthdr;
271 __be16 frag_off;
272 int offset;
273
274 if (ipv6_ext_hdr(nexthdr)) {
275 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
276 if (offset < 0)
277 return 0;
278 } else
279 offset = sizeof(struct ipv6hdr);
280
281 if (nexthdr == IPPROTO_ICMPV6) {
282 struct icmp6hdr *icmp6;
283
284 if (!pskb_may_pull(skb, (skb_network_header(skb) +
285 offset + 1 - skb->data)))
286 return 0;
287
288 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
289
290 switch (icmp6->icmp6_type) {
291 case NDISC_ROUTER_SOLICITATION:
292 case NDISC_ROUTER_ADVERTISEMENT:
293 case NDISC_NEIGHBOUR_SOLICITATION:
294 case NDISC_NEIGHBOUR_ADVERTISEMENT:
295 case NDISC_REDIRECT:
296 /* For reaction involving unicast neighbor discovery
297 * message destined to the proxied address, pass it to
298 * input function.
299 */
300 return 1;
301 default:
302 break;
303 }
304 }
305
306 /*
307 * The proxying router can't forward traffic sent to a link-local
308 * address, so signal the sender and discard the packet. This
309 * behavior is clarified by the MIPv6 specification.
310 */
311 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
312 dst_link_failure(skb);
313 return -1;
314 }
315
316 return 0;
317 }
318
319 static inline int ip6_forward_finish(struct sk_buff *skb)
320 {
321 return dst_output(skb);
322 }
323
324 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
325 {
326 unsigned int mtu;
327 struct inet6_dev *idev;
328
329 if (dst_metric_locked(dst, RTAX_MTU)) {
330 mtu = dst_metric_raw(dst, RTAX_MTU);
331 if (mtu)
332 return mtu;
333 }
334
335 mtu = IPV6_MIN_MTU;
336 rcu_read_lock();
337 idev = __in6_dev_get(dst->dev);
338 if (idev)
339 mtu = idev->cnf.mtu6;
340 rcu_read_unlock();
341
342 return mtu;
343 }
344
345 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
346 {
347 if (skb->len <= mtu)
348 return false;
349
350 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
351 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
352 return true;
353
354 if (skb->ignore_df)
355 return false;
356
357 if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
358 return false;
359
360 return true;
361 }
362
363 int ip6_forward(struct sk_buff *skb)
364 {
365 struct dst_entry *dst = skb_dst(skb);
366 struct ipv6hdr *hdr = ipv6_hdr(skb);
367 struct inet6_skb_parm *opt = IP6CB(skb);
368 struct net *net = dev_net(dst->dev);
369 u32 mtu;
370
371 if (net->ipv6.devconf_all->forwarding == 0)
372 goto error;
373
374 if (skb->pkt_type != PACKET_HOST)
375 goto drop;
376
377 if (skb_warn_if_lro(skb))
378 goto drop;
379
380 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
381 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
382 IPSTATS_MIB_INDISCARDS);
383 goto drop;
384 }
385
386 skb_forward_csum(skb);
387
388 /*
389 * We DO NOT make any processing on
390 * RA packets, pushing them to user level AS IS
391 * without ane WARRANTY that application will be able
392 * to interpret them. The reason is that we
393 * cannot make anything clever here.
394 *
395 * We are not end-node, so that if packet contains
396 * AH/ESP, we cannot make anything.
397 * Defragmentation also would be mistake, RA packets
398 * cannot be fragmented, because there is no warranty
399 * that different fragments will go along one path. --ANK
400 */
401 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
402 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
403 return 0;
404 }
405
406 /*
407 * check and decrement ttl
408 */
409 if (hdr->hop_limit <= 1) {
410 /* Force OUTPUT device used as source address */
411 skb->dev = dst->dev;
412 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
413 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
414 IPSTATS_MIB_INHDRERRORS);
415
416 kfree_skb(skb);
417 return -ETIMEDOUT;
418 }
419
420 /* XXX: idev->cnf.proxy_ndp? */
421 if (net->ipv6.devconf_all->proxy_ndp &&
422 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
423 int proxied = ip6_forward_proxy_check(skb);
424 if (proxied > 0)
425 return ip6_input(skb);
426 else if (proxied < 0) {
427 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
428 IPSTATS_MIB_INDISCARDS);
429 goto drop;
430 }
431 }
432
433 if (!xfrm6_route_forward(skb)) {
434 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
435 IPSTATS_MIB_INDISCARDS);
436 goto drop;
437 }
438 dst = skb_dst(skb);
439
440 /* IPv6 specs say nothing about it, but it is clear that we cannot
441 send redirects to source routed frames.
442 We don't send redirects to frames decapsulated from IPsec.
443 */
444 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
445 struct in6_addr *target = NULL;
446 struct inet_peer *peer;
447 struct rt6_info *rt;
448
449 /*
450 * incoming and outgoing devices are the same
451 * send a redirect.
452 */
453
454 rt = (struct rt6_info *) dst;
455 if (rt->rt6i_flags & RTF_GATEWAY)
456 target = &rt->rt6i_gateway;
457 else
458 target = &hdr->daddr;
459
460 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
461
462 /* Limit redirects both by destination (here)
463 and by source (inside ndisc_send_redirect)
464 */
465 if (inet_peer_xrlim_allow(peer, 1*HZ))
466 ndisc_send_redirect(skb, target);
467 if (peer)
468 inet_putpeer(peer);
469 } else {
470 int addrtype = ipv6_addr_type(&hdr->saddr);
471
472 /* This check is security critical. */
473 if (addrtype == IPV6_ADDR_ANY ||
474 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
475 goto error;
476 if (addrtype & IPV6_ADDR_LINKLOCAL) {
477 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
478 ICMPV6_NOT_NEIGHBOUR, 0);
479 goto error;
480 }
481 }
482
483 mtu = ip6_dst_mtu_forward(dst);
484 if (mtu < IPV6_MIN_MTU)
485 mtu = IPV6_MIN_MTU;
486
487 if (ip6_pkt_too_big(skb, mtu)) {
488 /* Again, force OUTPUT device used as source address */
489 skb->dev = dst->dev;
490 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
491 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
492 IPSTATS_MIB_INTOOBIGERRORS);
493 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
494 IPSTATS_MIB_FRAGFAILS);
495 kfree_skb(skb);
496 return -EMSGSIZE;
497 }
498
499 if (skb_cow(skb, dst->dev->hard_header_len)) {
500 IP6_INC_STATS_BH(net, ip6_dst_idev(dst),
501 IPSTATS_MIB_OUTDISCARDS);
502 goto drop;
503 }
504
505 hdr = ipv6_hdr(skb);
506
507 /* Mangling hops number delayed to point after skb COW */
508
509 hdr->hop_limit--;
510
511 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
512 IP6_ADD_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
513 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
514 ip6_forward_finish);
515
516 error:
517 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
518 drop:
519 kfree_skb(skb);
520 return -EINVAL;
521 }
522
523 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
524 {
525 to->pkt_type = from->pkt_type;
526 to->priority = from->priority;
527 to->protocol = from->protocol;
528 skb_dst_drop(to);
529 skb_dst_set(to, dst_clone(skb_dst(from)));
530 to->dev = from->dev;
531 to->mark = from->mark;
532
533 #ifdef CONFIG_NET_SCHED
534 to->tc_index = from->tc_index;
535 #endif
536 nf_copy(to, from);
537 skb_copy_secmark(to, from);
538 }
539
540 int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
541 {
542 struct sk_buff *frag;
543 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
544 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
545 struct ipv6hdr *tmp_hdr;
546 struct frag_hdr *fh;
547 unsigned int mtu, hlen, left, len;
548 int hroom, troom;
549 __be32 frag_id = 0;
550 int ptr, offset = 0, err = 0;
551 u8 *prevhdr, nexthdr = 0;
552 struct net *net = dev_net(skb_dst(skb)->dev);
553
554 hlen = ip6_find_1stfragopt(skb, &prevhdr);
555 nexthdr = *prevhdr;
556
557 mtu = ip6_skb_dst_mtu(skb);
558
559 /* We must not fragment if the socket is set to force MTU discovery
560 * or if the skb it not generated by a local socket.
561 */
562 if (unlikely(!skb->ignore_df && skb->len > mtu) ||
563 (IP6CB(skb)->frag_max_size &&
564 IP6CB(skb)->frag_max_size > mtu)) {
565 if (skb->sk && dst_allfrag(skb_dst(skb)))
566 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
567
568 skb->dev = skb_dst(skb)->dev;
569 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
570 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
571 IPSTATS_MIB_FRAGFAILS);
572 kfree_skb(skb);
573 return -EMSGSIZE;
574 }
575
576 if (np && np->frag_size < mtu) {
577 if (np->frag_size)
578 mtu = np->frag_size;
579 }
580 mtu -= hlen + sizeof(struct frag_hdr);
581
582 if (skb_has_frag_list(skb)) {
583 int first_len = skb_pagelen(skb);
584 struct sk_buff *frag2;
585
586 if (first_len - hlen > mtu ||
587 ((first_len - hlen) & 7) ||
588 skb_cloned(skb))
589 goto slow_path;
590
591 skb_walk_frags(skb, frag) {
592 /* Correct geometry. */
593 if (frag->len > mtu ||
594 ((frag->len & 7) && frag->next) ||
595 skb_headroom(frag) < hlen)
596 goto slow_path_clean;
597
598 /* Partially cloned skb? */
599 if (skb_shared(frag))
600 goto slow_path_clean;
601
602 BUG_ON(frag->sk);
603 if (skb->sk) {
604 frag->sk = skb->sk;
605 frag->destructor = sock_wfree;
606 }
607 skb->truesize -= frag->truesize;
608 }
609
610 err = 0;
611 offset = 0;
612 frag = skb_shinfo(skb)->frag_list;
613 skb_frag_list_init(skb);
614 /* BUILD HEADER */
615
616 *prevhdr = NEXTHDR_FRAGMENT;
617 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
618 if (!tmp_hdr) {
619 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
620 IPSTATS_MIB_FRAGFAILS);
621 return -ENOMEM;
622 }
623
624 __skb_pull(skb, hlen);
625 fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
626 __skb_push(skb, hlen);
627 skb_reset_network_header(skb);
628 memcpy(skb_network_header(skb), tmp_hdr, hlen);
629
630 ipv6_select_ident(fh, rt);
631 fh->nexthdr = nexthdr;
632 fh->reserved = 0;
633 fh->frag_off = htons(IP6_MF);
634 frag_id = fh->identification;
635
636 first_len = skb_pagelen(skb);
637 skb->data_len = first_len - skb_headlen(skb);
638 skb->len = first_len;
639 ipv6_hdr(skb)->payload_len = htons(first_len -
640 sizeof(struct ipv6hdr));
641
642 dst_hold(&rt->dst);
643
644 for (;;) {
645 /* Prepare header of the next frame,
646 * before previous one went down. */
647 if (frag) {
648 frag->ip_summed = CHECKSUM_NONE;
649 skb_reset_transport_header(frag);
650 fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
651 __skb_push(frag, hlen);
652 skb_reset_network_header(frag);
653 memcpy(skb_network_header(frag), tmp_hdr,
654 hlen);
655 offset += skb->len - hlen - sizeof(struct frag_hdr);
656 fh->nexthdr = nexthdr;
657 fh->reserved = 0;
658 fh->frag_off = htons(offset);
659 if (frag->next != NULL)
660 fh->frag_off |= htons(IP6_MF);
661 fh->identification = frag_id;
662 ipv6_hdr(frag)->payload_len =
663 htons(frag->len -
664 sizeof(struct ipv6hdr));
665 ip6_copy_metadata(frag, skb);
666 }
667
668 err = output(skb);
669 if (!err)
670 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
671 IPSTATS_MIB_FRAGCREATES);
672
673 if (err || !frag)
674 break;
675
676 skb = frag;
677 frag = skb->next;
678 skb->next = NULL;
679 }
680
681 kfree(tmp_hdr);
682
683 if (err == 0) {
684 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
685 IPSTATS_MIB_FRAGOKS);
686 ip6_rt_put(rt);
687 return 0;
688 }
689
690 kfree_skb_list(frag);
691
692 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
693 IPSTATS_MIB_FRAGFAILS);
694 ip6_rt_put(rt);
695 return err;
696
697 slow_path_clean:
698 skb_walk_frags(skb, frag2) {
699 if (frag2 == frag)
700 break;
701 frag2->sk = NULL;
702 frag2->destructor = NULL;
703 skb->truesize += frag2->truesize;
704 }
705 }
706
707 slow_path:
708 if ((skb->ip_summed == CHECKSUM_PARTIAL) &&
709 skb_checksum_help(skb))
710 goto fail;
711
712 left = skb->len - hlen; /* Space per frame */
713 ptr = hlen; /* Where to start from */
714
715 /*
716 * Fragment the datagram.
717 */
718
719 *prevhdr = NEXTHDR_FRAGMENT;
720 hroom = LL_RESERVED_SPACE(rt->dst.dev);
721 troom = rt->dst.dev->needed_tailroom;
722
723 /*
724 * Keep copying data until we run out.
725 */
726 while (left > 0) {
727 len = left;
728 /* IF: it doesn't fit, use 'mtu' - the data space left */
729 if (len > mtu)
730 len = mtu;
731 /* IF: we are not sending up to and including the packet end
732 then align the next start on an eight byte boundary */
733 if (len < left) {
734 len &= ~7;
735 }
736
737 /* Allocate buffer */
738 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
739 hroom + troom, GFP_ATOMIC);
740 if (!frag) {
741 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
742 IPSTATS_MIB_FRAGFAILS);
743 err = -ENOMEM;
744 goto fail;
745 }
746
747 /*
748 * Set up data on packet
749 */
750
751 ip6_copy_metadata(frag, skb);
752 skb_reserve(frag, hroom);
753 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
754 skb_reset_network_header(frag);
755 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
756 frag->transport_header = (frag->network_header + hlen +
757 sizeof(struct frag_hdr));
758
759 /*
760 * Charge the memory for the fragment to any owner
761 * it might possess
762 */
763 if (skb->sk)
764 skb_set_owner_w(frag, skb->sk);
765
766 /*
767 * Copy the packet header into the new buffer.
768 */
769 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
770
771 /*
772 * Build fragment header.
773 */
774 fh->nexthdr = nexthdr;
775 fh->reserved = 0;
776 if (!frag_id) {
777 ipv6_select_ident(fh, rt);
778 frag_id = fh->identification;
779 } else
780 fh->identification = frag_id;
781
782 /*
783 * Copy a block of the IP datagram.
784 */
785 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
786 len));
787 left -= len;
788
789 fh->frag_off = htons(offset);
790 if (left > 0)
791 fh->frag_off |= htons(IP6_MF);
792 ipv6_hdr(frag)->payload_len = htons(frag->len -
793 sizeof(struct ipv6hdr));
794
795 ptr += len;
796 offset += len;
797
798 /*
799 * Put this fragment into the sending queue.
800 */
801 err = output(frag);
802 if (err)
803 goto fail;
804
805 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
806 IPSTATS_MIB_FRAGCREATES);
807 }
808 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
809 IPSTATS_MIB_FRAGOKS);
810 consume_skb(skb);
811 return err;
812
813 fail:
814 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
815 IPSTATS_MIB_FRAGFAILS);
816 kfree_skb(skb);
817 return err;
818 }
819
820 static inline int ip6_rt_check(const struct rt6key *rt_key,
821 const struct in6_addr *fl_addr,
822 const struct in6_addr *addr_cache)
823 {
824 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
825 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
826 }
827
828 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
829 struct dst_entry *dst,
830 const struct flowi6 *fl6)
831 {
832 struct ipv6_pinfo *np = inet6_sk(sk);
833 struct rt6_info *rt;
834
835 if (!dst)
836 goto out;
837
838 if (dst->ops->family != AF_INET6) {
839 dst_release(dst);
840 return NULL;
841 }
842
843 rt = (struct rt6_info *)dst;
844 /* Yes, checking route validity in not connected
845 * case is not very simple. Take into account,
846 * that we do not support routing by source, TOS,
847 * and MSG_DONTROUTE --ANK (980726)
848 *
849 * 1. ip6_rt_check(): If route was host route,
850 * check that cached destination is current.
851 * If it is network route, we still may
852 * check its validity using saved pointer
853 * to the last used address: daddr_cache.
854 * We do not want to save whole address now,
855 * (because main consumer of this service
856 * is tcp, which has not this problem),
857 * so that the last trick works only on connected
858 * sockets.
859 * 2. oif also should be the same.
860 */
861 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
862 #ifdef CONFIG_IPV6_SUBTREES
863 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
864 #endif
865 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
866 dst_release(dst);
867 dst = NULL;
868 }
869
870 out:
871 return dst;
872 }
873
874 static int ip6_dst_lookup_tail(struct sock *sk,
875 struct dst_entry **dst, struct flowi6 *fl6)
876 {
877 struct net *net = sock_net(sk);
878 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
879 struct neighbour *n;
880 struct rt6_info *rt;
881 #endif
882 int err;
883
884 if (*dst == NULL)
885 *dst = ip6_route_output(net, sk, fl6);
886
887 err = (*dst)->error;
888 if (err)
889 goto out_err_release;
890
891 if (ipv6_addr_any(&fl6->saddr)) {
892 struct rt6_info *rt = (struct rt6_info *) *dst;
893 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
894 sk ? inet6_sk(sk)->srcprefs : 0,
895 &fl6->saddr);
896 if (err)
897 goto out_err_release;
898 }
899
900 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
901 /*
902 * Here if the dst entry we've looked up
903 * has a neighbour entry that is in the INCOMPLETE
904 * state and the src address from the flow is
905 * marked as OPTIMISTIC, we release the found
906 * dst entry and replace it instead with the
907 * dst entry of the nexthop router
908 */
909 rt = (struct rt6_info *) *dst;
910 rcu_read_lock_bh();
911 n = __ipv6_neigh_lookup_noref(rt->dst.dev, rt6_nexthop(rt));
912 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
913 rcu_read_unlock_bh();
914
915 if (err) {
916 struct inet6_ifaddr *ifp;
917 struct flowi6 fl_gw6;
918 int redirect;
919
920 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
921 (*dst)->dev, 1);
922
923 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
924 if (ifp)
925 in6_ifa_put(ifp);
926
927 if (redirect) {
928 /*
929 * We need to get the dst entry for the
930 * default router instead
931 */
932 dst_release(*dst);
933 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
934 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
935 *dst = ip6_route_output(net, sk, &fl_gw6);
936 err = (*dst)->error;
937 if (err)
938 goto out_err_release;
939 }
940 }
941 #endif
942
943 return 0;
944
945 out_err_release:
946 if (err == -ENETUNREACH)
947 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
948 dst_release(*dst);
949 *dst = NULL;
950 return err;
951 }
952
953 /**
954 * ip6_dst_lookup - perform route lookup on flow
955 * @sk: socket which provides route info
956 * @dst: pointer to dst_entry * for result
957 * @fl6: flow to lookup
958 *
959 * This function performs a route lookup on the given flow.
960 *
961 * It returns zero on success, or a standard errno code on error.
962 */
963 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
964 {
965 *dst = NULL;
966 return ip6_dst_lookup_tail(sk, dst, fl6);
967 }
968 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
969
970 /**
971 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
972 * @sk: socket which provides route info
973 * @fl6: flow to lookup
974 * @final_dst: final destination address for ipsec lookup
975 *
976 * This function performs a route lookup on the given flow.
977 *
978 * It returns a valid dst pointer on success, or a pointer encoded
979 * error code.
980 */
981 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
982 const struct in6_addr *final_dst)
983 {
984 struct dst_entry *dst = NULL;
985 int err;
986
987 err = ip6_dst_lookup_tail(sk, &dst, fl6);
988 if (err)
989 return ERR_PTR(err);
990 if (final_dst)
991 fl6->daddr = *final_dst;
992
993 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
994 }
995 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
996
997 /**
998 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
999 * @sk: socket which provides the dst cache and route info
1000 * @fl6: flow to lookup
1001 * @final_dst: final destination address for ipsec lookup
1002 *
1003 * This function performs a route lookup on the given flow with the
1004 * possibility of using the cached route in the socket if it is valid.
1005 * It will take the socket dst lock when operating on the dst cache.
1006 * As a result, this function can only be used in process context.
1007 *
1008 * It returns a valid dst pointer on success, or a pointer encoded
1009 * error code.
1010 */
1011 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1012 const struct in6_addr *final_dst)
1013 {
1014 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1015 int err;
1016
1017 dst = ip6_sk_dst_check(sk, dst, fl6);
1018
1019 err = ip6_dst_lookup_tail(sk, &dst, fl6);
1020 if (err)
1021 return ERR_PTR(err);
1022 if (final_dst)
1023 fl6->daddr = *final_dst;
1024
1025 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1026 }
1027 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1028
1029 static inline int ip6_ufo_append_data(struct sock *sk,
1030 int getfrag(void *from, char *to, int offset, int len,
1031 int odd, struct sk_buff *skb),
1032 void *from, int length, int hh_len, int fragheaderlen,
1033 int transhdrlen, int mtu, unsigned int flags,
1034 struct rt6_info *rt)
1035
1036 {
1037 struct sk_buff *skb;
1038 struct frag_hdr fhdr;
1039 int err;
1040
1041 /* There is support for UDP large send offload by network
1042 * device, so create one single skb packet containing complete
1043 * udp datagram
1044 */
1045 skb = skb_peek_tail(&sk->sk_write_queue);
1046 if (skb == NULL) {
1047 skb = sock_alloc_send_skb(sk,
1048 hh_len + fragheaderlen + transhdrlen + 20,
1049 (flags & MSG_DONTWAIT), &err);
1050 if (skb == NULL)
1051 return err;
1052
1053 /* reserve space for Hardware header */
1054 skb_reserve(skb, hh_len);
1055
1056 /* create space for UDP/IP header */
1057 skb_put(skb, fragheaderlen + transhdrlen);
1058
1059 /* initialize network header pointer */
1060 skb_reset_network_header(skb);
1061
1062 /* initialize protocol header pointer */
1063 skb->transport_header = skb->network_header + fragheaderlen;
1064
1065 skb->protocol = htons(ETH_P_IPV6);
1066 skb->csum = 0;
1067
1068 __skb_queue_tail(&sk->sk_write_queue, skb);
1069 } else if (skb_is_gso(skb)) {
1070 goto append;
1071 }
1072
1073 skb->ip_summed = CHECKSUM_PARTIAL;
1074 /* Specify the length of each IPv6 datagram fragment.
1075 * It has to be a multiple of 8.
1076 */
1077 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1078 sizeof(struct frag_hdr)) & ~7;
1079 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1080 ipv6_select_ident(&fhdr, rt);
1081 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1082
1083 append:
1084 return skb_append_datato_frags(sk, skb, getfrag, from,
1085 (length - transhdrlen));
1086 }
1087
1088 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1089 gfp_t gfp)
1090 {
1091 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1092 }
1093
1094 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1095 gfp_t gfp)
1096 {
1097 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1098 }
1099
1100 static void ip6_append_data_mtu(unsigned int *mtu,
1101 int *maxfraglen,
1102 unsigned int fragheaderlen,
1103 struct sk_buff *skb,
1104 struct rt6_info *rt,
1105 unsigned int orig_mtu)
1106 {
1107 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1108 if (skb == NULL) {
1109 /* first fragment, reserve header_len */
1110 *mtu = orig_mtu - rt->dst.header_len;
1111
1112 } else {
1113 /*
1114 * this fragment is not first, the headers
1115 * space is regarded as data space.
1116 */
1117 *mtu = orig_mtu;
1118 }
1119 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1120 + fragheaderlen - sizeof(struct frag_hdr);
1121 }
1122 }
1123
1124 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1125 int offset, int len, int odd, struct sk_buff *skb),
1126 void *from, int length, int transhdrlen,
1127 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1128 struct rt6_info *rt, unsigned int flags, int dontfrag)
1129 {
1130 struct inet_sock *inet = inet_sk(sk);
1131 struct ipv6_pinfo *np = inet6_sk(sk);
1132 struct inet_cork *cork;
1133 struct sk_buff *skb, *skb_prev = NULL;
1134 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1135 int exthdrlen;
1136 int dst_exthdrlen;
1137 int hh_len;
1138 int copy;
1139 int err;
1140 int offset = 0;
1141 __u8 tx_flags = 0;
1142 u32 tskey = 0;
1143
1144 if (flags&MSG_PROBE)
1145 return 0;
1146 cork = &inet->cork.base;
1147 if (skb_queue_empty(&sk->sk_write_queue)) {
1148 /*
1149 * setup for corking
1150 */
1151 if (opt) {
1152 if (WARN_ON(np->cork.opt))
1153 return -EINVAL;
1154
1155 np->cork.opt = kzalloc(opt->tot_len, sk->sk_allocation);
1156 if (unlikely(np->cork.opt == NULL))
1157 return -ENOBUFS;
1158
1159 np->cork.opt->tot_len = opt->tot_len;
1160 np->cork.opt->opt_flen = opt->opt_flen;
1161 np->cork.opt->opt_nflen = opt->opt_nflen;
1162
1163 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1164 sk->sk_allocation);
1165 if (opt->dst0opt && !np->cork.opt->dst0opt)
1166 return -ENOBUFS;
1167
1168 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1169 sk->sk_allocation);
1170 if (opt->dst1opt && !np->cork.opt->dst1opt)
1171 return -ENOBUFS;
1172
1173 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1174 sk->sk_allocation);
1175 if (opt->hopopt && !np->cork.opt->hopopt)
1176 return -ENOBUFS;
1177
1178 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1179 sk->sk_allocation);
1180 if (opt->srcrt && !np->cork.opt->srcrt)
1181 return -ENOBUFS;
1182
1183 /* need source address above miyazawa*/
1184 }
1185 dst_hold(&rt->dst);
1186 cork->dst = &rt->dst;
1187 inet->cork.fl.u.ip6 = *fl6;
1188 np->cork.hop_limit = hlimit;
1189 np->cork.tclass = tclass;
1190 if (rt->dst.flags & DST_XFRM_TUNNEL)
1191 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1192 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1193 else
1194 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1195 rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1196 if (np->frag_size < mtu) {
1197 if (np->frag_size)
1198 mtu = np->frag_size;
1199 }
1200 cork->fragsize = mtu;
1201 if (dst_allfrag(rt->dst.path))
1202 cork->flags |= IPCORK_ALLFRAG;
1203 cork->length = 0;
1204 exthdrlen = (opt ? opt->opt_flen : 0);
1205 length += exthdrlen;
1206 transhdrlen += exthdrlen;
1207 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1208 } else {
1209 rt = (struct rt6_info *)cork->dst;
1210 fl6 = &inet->cork.fl.u.ip6;
1211 opt = np->cork.opt;
1212 transhdrlen = 0;
1213 exthdrlen = 0;
1214 dst_exthdrlen = 0;
1215 mtu = cork->fragsize;
1216 }
1217 orig_mtu = mtu;
1218
1219 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1220
1221 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1222 (opt ? opt->opt_nflen : 0);
1223 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1224 sizeof(struct frag_hdr);
1225
1226 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1227 unsigned int maxnonfragsize, headersize;
1228
1229 headersize = sizeof(struct ipv6hdr) +
1230 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1231 (dst_allfrag(&rt->dst) ?
1232 sizeof(struct frag_hdr) : 0) +
1233 rt->rt6i_nfheader_len;
1234
1235 if (ip6_sk_ignore_df(sk))
1236 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1237 else
1238 maxnonfragsize = mtu;
1239
1240 /* dontfrag active */
1241 if ((cork->length + length > mtu - headersize) && dontfrag &&
1242 (sk->sk_protocol == IPPROTO_UDP ||
1243 sk->sk_protocol == IPPROTO_RAW)) {
1244 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1245 sizeof(struct ipv6hdr));
1246 goto emsgsize;
1247 }
1248
1249 if (cork->length + length > maxnonfragsize - headersize) {
1250 emsgsize:
1251 ipv6_local_error(sk, EMSGSIZE, fl6,
1252 mtu - headersize +
1253 sizeof(struct ipv6hdr));
1254 return -EMSGSIZE;
1255 }
1256 }
1257
1258 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1259 sock_tx_timestamp(sk, &tx_flags);
1260 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1261 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1262 tskey = sk->sk_tskey++;
1263 }
1264
1265 /*
1266 * Let's try using as much space as possible.
1267 * Use MTU if total length of the message fits into the MTU.
1268 * Otherwise, we need to reserve fragment header and
1269 * fragment alignment (= 8-15 octects, in total).
1270 *
1271 * Note that we may need to "move" the data from the tail of
1272 * of the buffer to the new fragment when we split
1273 * the message.
1274 *
1275 * FIXME: It may be fragmented into multiple chunks
1276 * at once if non-fragmentable extension headers
1277 * are too large.
1278 * --yoshfuji
1279 */
1280
1281 skb = skb_peek_tail(&sk->sk_write_queue);
1282 cork->length += length;
1283 if (((length > mtu) ||
1284 (skb && skb_is_gso(skb))) &&
1285 (sk->sk_protocol == IPPROTO_UDP) &&
1286 (rt->dst.dev->features & NETIF_F_UFO)) {
1287 err = ip6_ufo_append_data(sk, getfrag, from, length,
1288 hh_len, fragheaderlen,
1289 transhdrlen, mtu, flags, rt);
1290 if (err)
1291 goto error;
1292 return 0;
1293 }
1294
1295 if (!skb)
1296 goto alloc_new_skb;
1297
1298 while (length > 0) {
1299 /* Check if the remaining data fits into current packet. */
1300 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1301 if (copy < length)
1302 copy = maxfraglen - skb->len;
1303
1304 if (copy <= 0) {
1305 char *data;
1306 unsigned int datalen;
1307 unsigned int fraglen;
1308 unsigned int fraggap;
1309 unsigned int alloclen;
1310 alloc_new_skb:
1311 /* There's no room in the current skb */
1312 if (skb)
1313 fraggap = skb->len - maxfraglen;
1314 else
1315 fraggap = 0;
1316 /* update mtu and maxfraglen if necessary */
1317 if (skb == NULL || skb_prev == NULL)
1318 ip6_append_data_mtu(&mtu, &maxfraglen,
1319 fragheaderlen, skb, rt,
1320 orig_mtu);
1321
1322 skb_prev = skb;
1323
1324 /*
1325 * If remaining data exceeds the mtu,
1326 * we know we need more fragment(s).
1327 */
1328 datalen = length + fraggap;
1329
1330 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1331 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1332 if ((flags & MSG_MORE) &&
1333 !(rt->dst.dev->features&NETIF_F_SG))
1334 alloclen = mtu;
1335 else
1336 alloclen = datalen + fragheaderlen;
1337
1338 alloclen += dst_exthdrlen;
1339
1340 if (datalen != length + fraggap) {
1341 /*
1342 * this is not the last fragment, the trailer
1343 * space is regarded as data space.
1344 */
1345 datalen += rt->dst.trailer_len;
1346 }
1347
1348 alloclen += rt->dst.trailer_len;
1349 fraglen = datalen + fragheaderlen;
1350
1351 /*
1352 * We just reserve space for fragment header.
1353 * Note: this may be overallocation if the message
1354 * (without MSG_MORE) fits into the MTU.
1355 */
1356 alloclen += sizeof(struct frag_hdr);
1357
1358 if (transhdrlen) {
1359 skb = sock_alloc_send_skb(sk,
1360 alloclen + hh_len,
1361 (flags & MSG_DONTWAIT), &err);
1362 } else {
1363 skb = NULL;
1364 if (atomic_read(&sk->sk_wmem_alloc) <=
1365 2 * sk->sk_sndbuf)
1366 skb = sock_wmalloc(sk,
1367 alloclen + hh_len, 1,
1368 sk->sk_allocation);
1369 if (unlikely(skb == NULL))
1370 err = -ENOBUFS;
1371 }
1372 if (skb == NULL)
1373 goto error;
1374 /*
1375 * Fill in the control structures
1376 */
1377 skb->protocol = htons(ETH_P_IPV6);
1378 skb->ip_summed = CHECKSUM_NONE;
1379 skb->csum = 0;
1380 /* reserve for fragmentation and ipsec header */
1381 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1382 dst_exthdrlen);
1383
1384 /* Only the initial fragment is time stamped */
1385 skb_shinfo(skb)->tx_flags = tx_flags;
1386 tx_flags = 0;
1387 skb_shinfo(skb)->tskey = tskey;
1388 tskey = 0;
1389
1390 /*
1391 * Find where to start putting bytes
1392 */
1393 data = skb_put(skb, fraglen);
1394 skb_set_network_header(skb, exthdrlen);
1395 data += fragheaderlen;
1396 skb->transport_header = (skb->network_header +
1397 fragheaderlen);
1398 if (fraggap) {
1399 skb->csum = skb_copy_and_csum_bits(
1400 skb_prev, maxfraglen,
1401 data + transhdrlen, fraggap, 0);
1402 skb_prev->csum = csum_sub(skb_prev->csum,
1403 skb->csum);
1404 data += fraggap;
1405 pskb_trim_unique(skb_prev, maxfraglen);
1406 }
1407 copy = datalen - transhdrlen - fraggap;
1408
1409 if (copy < 0) {
1410 err = -EINVAL;
1411 kfree_skb(skb);
1412 goto error;
1413 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1414 err = -EFAULT;
1415 kfree_skb(skb);
1416 goto error;
1417 }
1418
1419 offset += copy;
1420 length -= datalen - fraggap;
1421 transhdrlen = 0;
1422 exthdrlen = 0;
1423 dst_exthdrlen = 0;
1424
1425 /*
1426 * Put the packet on the pending queue
1427 */
1428 __skb_queue_tail(&sk->sk_write_queue, skb);
1429 continue;
1430 }
1431
1432 if (copy > length)
1433 copy = length;
1434
1435 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1436 unsigned int off;
1437
1438 off = skb->len;
1439 if (getfrag(from, skb_put(skb, copy),
1440 offset, copy, off, skb) < 0) {
1441 __skb_trim(skb, off);
1442 err = -EFAULT;
1443 goto error;
1444 }
1445 } else {
1446 int i = skb_shinfo(skb)->nr_frags;
1447 struct page_frag *pfrag = sk_page_frag(sk);
1448
1449 err = -ENOMEM;
1450 if (!sk_page_frag_refill(sk, pfrag))
1451 goto error;
1452
1453 if (!skb_can_coalesce(skb, i, pfrag->page,
1454 pfrag->offset)) {
1455 err = -EMSGSIZE;
1456 if (i == MAX_SKB_FRAGS)
1457 goto error;
1458
1459 __skb_fill_page_desc(skb, i, pfrag->page,
1460 pfrag->offset, 0);
1461 skb_shinfo(skb)->nr_frags = ++i;
1462 get_page(pfrag->page);
1463 }
1464 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1465 if (getfrag(from,
1466 page_address(pfrag->page) + pfrag->offset,
1467 offset, copy, skb->len, skb) < 0)
1468 goto error_efault;
1469
1470 pfrag->offset += copy;
1471 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1472 skb->len += copy;
1473 skb->data_len += copy;
1474 skb->truesize += copy;
1475 atomic_add(copy, &sk->sk_wmem_alloc);
1476 }
1477 offset += copy;
1478 length -= copy;
1479 }
1480
1481 return 0;
1482
1483 error_efault:
1484 err = -EFAULT;
1485 error:
1486 cork->length -= length;
1487 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1488 return err;
1489 }
1490 EXPORT_SYMBOL_GPL(ip6_append_data);
1491
1492 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1493 {
1494 if (np->cork.opt) {
1495 kfree(np->cork.opt->dst0opt);
1496 kfree(np->cork.opt->dst1opt);
1497 kfree(np->cork.opt->hopopt);
1498 kfree(np->cork.opt->srcrt);
1499 kfree(np->cork.opt);
1500 np->cork.opt = NULL;
1501 }
1502
1503 if (inet->cork.base.dst) {
1504 dst_release(inet->cork.base.dst);
1505 inet->cork.base.dst = NULL;
1506 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1507 }
1508 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1509 }
1510
1511 int ip6_push_pending_frames(struct sock *sk)
1512 {
1513 struct sk_buff *skb, *tmp_skb;
1514 struct sk_buff **tail_skb;
1515 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1516 struct inet_sock *inet = inet_sk(sk);
1517 struct ipv6_pinfo *np = inet6_sk(sk);
1518 struct net *net = sock_net(sk);
1519 struct ipv6hdr *hdr;
1520 struct ipv6_txoptions *opt = np->cork.opt;
1521 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1522 struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1523 unsigned char proto = fl6->flowi6_proto;
1524 int err = 0;
1525
1526 skb = __skb_dequeue(&sk->sk_write_queue);
1527 if (skb == NULL)
1528 goto out;
1529 tail_skb = &(skb_shinfo(skb)->frag_list);
1530
1531 /* move skb->data to ip header from ext header */
1532 if (skb->data < skb_network_header(skb))
1533 __skb_pull(skb, skb_network_offset(skb));
1534 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1535 __skb_pull(tmp_skb, skb_network_header_len(skb));
1536 *tail_skb = tmp_skb;
1537 tail_skb = &(tmp_skb->next);
1538 skb->len += tmp_skb->len;
1539 skb->data_len += tmp_skb->len;
1540 skb->truesize += tmp_skb->truesize;
1541 tmp_skb->destructor = NULL;
1542 tmp_skb->sk = NULL;
1543 }
1544
1545 /* Allow local fragmentation. */
1546 skb->ignore_df = ip6_sk_ignore_df(sk);
1547
1548 *final_dst = fl6->daddr;
1549 __skb_pull(skb, skb_network_header_len(skb));
1550 if (opt && opt->opt_flen)
1551 ipv6_push_frag_opts(skb, opt, &proto);
1552 if (opt && opt->opt_nflen)
1553 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1554
1555 skb_push(skb, sizeof(struct ipv6hdr));
1556 skb_reset_network_header(skb);
1557 hdr = ipv6_hdr(skb);
1558
1559 ip6_flow_hdr(hdr, np->cork.tclass,
1560 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1561 np->autoflowlabel));
1562 hdr->hop_limit = np->cork.hop_limit;
1563 hdr->nexthdr = proto;
1564 hdr->saddr = fl6->saddr;
1565 hdr->daddr = *final_dst;
1566
1567 skb->priority = sk->sk_priority;
1568 skb->mark = sk->sk_mark;
1569
1570 skb_dst_set(skb, dst_clone(&rt->dst));
1571 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1572 if (proto == IPPROTO_ICMPV6) {
1573 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1574
1575 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1576 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1577 }
1578
1579 err = ip6_local_out(skb);
1580 if (err) {
1581 if (err > 0)
1582 err = net_xmit_errno(err);
1583 if (err)
1584 goto error;
1585 }
1586
1587 out:
1588 ip6_cork_release(inet, np);
1589 return err;
1590 error:
1591 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1592 goto out;
1593 }
1594 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1595
1596 void ip6_flush_pending_frames(struct sock *sk)
1597 {
1598 struct sk_buff *skb;
1599
1600 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1601 if (skb_dst(skb))
1602 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1603 IPSTATS_MIB_OUTDISCARDS);
1604 kfree_skb(skb);
1605 }
1606
1607 ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1608 }
1609 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
Linux kernel - Deliverables
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