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coccinelle: Improve setup_timer.cocci matching
[linux-2.6/btrfs-unstable.git] / net / ipv6 / ip6_output.c
blob43ca864327c73015f1724879d7ee8268a0de513b
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/bpf-cgroup.h>
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 #include <linux/mroute6.h>
59 #include <net/l3mdev.h>
60 #include <net/lwtunnel.h>
61
62 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
63 {
64 struct dst_entry *dst = skb_dst(skb);
65 struct net_device *dev = dst->dev;
66 struct neighbour *neigh;
67 struct in6_addr *nexthop;
68 int ret;
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(sk) &&
74 ((mroute6_socket(net, 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 net, sk, newskb, NULL, newskb->dev,
86 dev_loopback_xmit);
87
88 if (ipv6_hdr(skb)->hop_limit == 0) {
89 IP6_INC_STATS(net, idev,
90 IPSTATS_MIB_OUTDISCARDS);
91 kfree_skb(skb);
92 return 0;
93 }
94 }
95
96 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
97
98 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
99 IPV6_ADDR_SCOPE_NODELOCAL &&
100 !(dev->flags & IFF_LOOPBACK)) {
101 kfree_skb(skb);
102 return 0;
103 }
104 }
105
106 if (lwtunnel_xmit_redirect(dst->lwtstate)) {
107 int res = lwtunnel_xmit(skb);
108
109 if (res < 0 || res == LWTUNNEL_XMIT_DONE)
110 return res;
111 }
112
113 rcu_read_lock_bh();
114 nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
115 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
116 if (unlikely(!neigh))
117 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
118 if (!IS_ERR(neigh)) {
119 sock_confirm_neigh(skb, neigh);
120 ret = neigh_output(neigh, skb);
121 rcu_read_unlock_bh();
122 return ret;
123 }
124 rcu_read_unlock_bh();
125
126 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
127 kfree_skb(skb);
128 return -EINVAL;
129 }
130
131 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
132 {
133 int ret;
134
135 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
136 if (ret) {
137 kfree_skb(skb);
138 return ret;
139 }
140
141 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
142 dst_allfrag(skb_dst(skb)) ||
143 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
144 return ip6_fragment(net, sk, skb, ip6_finish_output2);
145 else
146 return ip6_finish_output2(net, sk, skb);
147 }
148
149 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
150 {
151 struct net_device *dev = skb_dst(skb)->dev;
152 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
153
154 skb->protocol = htons(ETH_P_IPV6);
155 skb->dev = dev;
156
157 if (unlikely(idev->cnf.disable_ipv6)) {
158 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
159 kfree_skb(skb);
160 return 0;
161 }
162
163 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
164 net, sk, skb, NULL, dev,
165 ip6_finish_output,
166 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
167 }
168
169 /*
170 * xmit an sk_buff (used by TCP, SCTP and DCCP)
171 * Note : socket lock is not held for SYNACK packets, but might be modified
172 * by calls to skb_set_owner_w() and ipv6_local_error(),
173 * which are using proper atomic operations or spinlocks.
174 */
175 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
176 __u32 mark, struct ipv6_txoptions *opt, int tclass)
177 {
178 struct net *net = sock_net(sk);
179 const struct ipv6_pinfo *np = inet6_sk(sk);
180 struct in6_addr *first_hop = &fl6->daddr;
181 struct dst_entry *dst = skb_dst(skb);
182 struct ipv6hdr *hdr;
183 u8 proto = fl6->flowi6_proto;
184 int seg_len = skb->len;
185 int hlimit = -1;
186 u32 mtu;
187
188 if (opt) {
189 unsigned int head_room;
190
191 /* First: exthdrs may take lots of space (~8K for now)
192 MAX_HEADER is not enough.
193 */
194 head_room = opt->opt_nflen + opt->opt_flen;
195 seg_len += head_room;
196 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
197
198 if (skb_headroom(skb) < head_room) {
199 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
200 if (!skb2) {
201 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
202 IPSTATS_MIB_OUTDISCARDS);
203 kfree_skb(skb);
204 return -ENOBUFS;
205 }
206 consume_skb(skb);
207 skb = skb2;
208 /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically,
209 * it is safe to call in our context (socket lock not held)
210 */
211 skb_set_owner_w(skb, (struct sock *)sk);
212 }
213 if (opt->opt_flen)
214 ipv6_push_frag_opts(skb, opt, &proto);
215 if (opt->opt_nflen)
216 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,
217 &fl6->saddr);
218 }
219
220 skb_push(skb, sizeof(struct ipv6hdr));
221 skb_reset_network_header(skb);
222 hdr = ipv6_hdr(skb);
223
224 /*
225 * Fill in the IPv6 header
226 */
227 if (np)
228 hlimit = np->hop_limit;
229 if (hlimit < 0)
230 hlimit = ip6_dst_hoplimit(dst);
231
232 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
233 np->autoflowlabel, fl6));
234
235 hdr->payload_len = htons(seg_len);
236 hdr->nexthdr = proto;
237 hdr->hop_limit = hlimit;
238
239 hdr->saddr = fl6->saddr;
240 hdr->daddr = *first_hop;
241
242 skb->protocol = htons(ETH_P_IPV6);
243 skb->priority = sk->sk_priority;
244 skb->mark = mark;
245
246 mtu = dst_mtu(dst);
247 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
248 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
249 IPSTATS_MIB_OUT, skb->len);
250
251 /* if egress device is enslaved to an L3 master device pass the
252 * skb to its handler for processing
253 */
254 skb = l3mdev_ip6_out((struct sock *)sk, skb);
255 if (unlikely(!skb))
256 return 0;
257
258 /* hooks should never assume socket lock is held.
259 * we promote our socket to non const
260 */
261 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
262 net, (struct sock *)sk, skb, NULL, dst->dev,
263 dst_output);
264 }
265
266 skb->dev = dst->dev;
267 /* ipv6_local_error() does not require socket lock,
268 * we promote our socket to non const
269 */
270 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
271
272 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
273 kfree_skb(skb);
274 return -EMSGSIZE;
275 }
276 EXPORT_SYMBOL(ip6_xmit);
277
278 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
279 {
280 struct ip6_ra_chain *ra;
281 struct sock *last = NULL;
282
283 read_lock(&ip6_ra_lock);
284 for (ra = ip6_ra_chain; ra; ra = ra->next) {
285 struct sock *sk = ra->sk;
286 if (sk && ra->sel == sel &&
287 (!sk->sk_bound_dev_if ||
288 sk->sk_bound_dev_if == skb->dev->ifindex)) {
289 if (last) {
290 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
291 if (skb2)
292 rawv6_rcv(last, skb2);
293 }
294 last = sk;
295 }
296 }
297
298 if (last) {
299 rawv6_rcv(last, skb);
300 read_unlock(&ip6_ra_lock);
301 return 1;
302 }
303 read_unlock(&ip6_ra_lock);
304 return 0;
305 }
306
307 static int ip6_forward_proxy_check(struct sk_buff *skb)
308 {
309 struct ipv6hdr *hdr = ipv6_hdr(skb);
310 u8 nexthdr = hdr->nexthdr;
311 __be16 frag_off;
312 int offset;
313
314 if (ipv6_ext_hdr(nexthdr)) {
315 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
316 if (offset < 0)
317 return 0;
318 } else
319 offset = sizeof(struct ipv6hdr);
320
321 if (nexthdr == IPPROTO_ICMPV6) {
322 struct icmp6hdr *icmp6;
323
324 if (!pskb_may_pull(skb, (skb_network_header(skb) +
325 offset + 1 - skb->data)))
326 return 0;
327
328 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
329
330 switch (icmp6->icmp6_type) {
331 case NDISC_ROUTER_SOLICITATION:
332 case NDISC_ROUTER_ADVERTISEMENT:
333 case NDISC_NEIGHBOUR_SOLICITATION:
334 case NDISC_NEIGHBOUR_ADVERTISEMENT:
335 case NDISC_REDIRECT:
336 /* For reaction involving unicast neighbor discovery
337 * message destined to the proxied address, pass it to
338 * input function.
339 */
340 return 1;
341 default:
342 break;
343 }
344 }
345
346 /*
347 * The proxying router can't forward traffic sent to a link-local
348 * address, so signal the sender and discard the packet. This
349 * behavior is clarified by the MIPv6 specification.
350 */
351 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
352 dst_link_failure(skb);
353 return -1;
354 }
355
356 return 0;
357 }
358
359 static inline int ip6_forward_finish(struct net *net, struct sock *sk,
360 struct sk_buff *skb)
361 {
362 return dst_output(net, sk, skb);
363 }
364
365 static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
366 {
367 unsigned int mtu;
368 struct inet6_dev *idev;
369
370 if (dst_metric_locked(dst, RTAX_MTU)) {
371 mtu = dst_metric_raw(dst, RTAX_MTU);
372 if (mtu)
373 return mtu;
374 }
375
376 mtu = IPV6_MIN_MTU;
377 rcu_read_lock();
378 idev = __in6_dev_get(dst->dev);
379 if (idev)
380 mtu = idev->cnf.mtu6;
381 rcu_read_unlock();
382
383 return mtu;
384 }
385
386 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
387 {
388 if (skb->len <= mtu)
389 return false;
390
391 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
392 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
393 return true;
394
395 if (skb->ignore_df)
396 return false;
397
398 if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
399 return false;
400
401 return true;
402 }
403
404 int ip6_forward(struct sk_buff *skb)
405 {
406 struct dst_entry *dst = skb_dst(skb);
407 struct ipv6hdr *hdr = ipv6_hdr(skb);
408 struct inet6_skb_parm *opt = IP6CB(skb);
409 struct net *net = dev_net(dst->dev);
410 u32 mtu;
411
412 if (net->ipv6.devconf_all->forwarding == 0)
413 goto error;
414
415 if (skb->pkt_type != PACKET_HOST)
416 goto drop;
417
418 if (unlikely(skb->sk))
419 goto drop;
420
421 if (skb_warn_if_lro(skb))
422 goto drop;
423
424 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
425 __IP6_INC_STATS(net, ip6_dst_idev(dst),
426 IPSTATS_MIB_INDISCARDS);
427 goto drop;
428 }
429
430 skb_forward_csum(skb);
431
432 /*
433 * We DO NOT make any processing on
434 * RA packets, pushing them to user level AS IS
435 * without ane WARRANTY that application will be able
436 * to interpret them. The reason is that we
437 * cannot make anything clever here.
438 *
439 * We are not end-node, so that if packet contains
440 * AH/ESP, we cannot make anything.
441 * Defragmentation also would be mistake, RA packets
442 * cannot be fragmented, because there is no warranty
443 * that different fragments will go along one path. --ANK
444 */
445 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
446 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
447 return 0;
448 }
449
450 /*
451 * check and decrement ttl
452 */
453 if (hdr->hop_limit <= 1) {
454 /* Force OUTPUT device used as source address */
455 skb->dev = dst->dev;
456 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
457 __IP6_INC_STATS(net, ip6_dst_idev(dst),
458 IPSTATS_MIB_INHDRERRORS);
459
460 kfree_skb(skb);
461 return -ETIMEDOUT;
462 }
463
464 /* XXX: idev->cnf.proxy_ndp? */
465 if (net->ipv6.devconf_all->proxy_ndp &&
466 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
467 int proxied = ip6_forward_proxy_check(skb);
468 if (proxied > 0)
469 return ip6_input(skb);
470 else if (proxied < 0) {
471 __IP6_INC_STATS(net, ip6_dst_idev(dst),
472 IPSTATS_MIB_INDISCARDS);
473 goto drop;
474 }
475 }
476
477 if (!xfrm6_route_forward(skb)) {
478 __IP6_INC_STATS(net, ip6_dst_idev(dst),
479 IPSTATS_MIB_INDISCARDS);
480 goto drop;
481 }
482 dst = skb_dst(skb);
483
484 /* IPv6 specs say nothing about it, but it is clear that we cannot
485 send redirects to source routed frames.
486 We don't send redirects to frames decapsulated from IPsec.
487 */
488 if (skb->dev == dst->dev && opt->srcrt == 0 && !skb_sec_path(skb)) {
489 struct in6_addr *target = NULL;
490 struct inet_peer *peer;
491 struct rt6_info *rt;
492
493 /*
494 * incoming and outgoing devices are the same
495 * send a redirect.
496 */
497
498 rt = (struct rt6_info *) dst;
499 if (rt->rt6i_flags & RTF_GATEWAY)
500 target = &rt->rt6i_gateway;
501 else
502 target = &hdr->daddr;
503
504 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
505
506 /* Limit redirects both by destination (here)
507 and by source (inside ndisc_send_redirect)
508 */
509 if (inet_peer_xrlim_allow(peer, 1*HZ))
510 ndisc_send_redirect(skb, target);
511 if (peer)
512 inet_putpeer(peer);
513 } else {
514 int addrtype = ipv6_addr_type(&hdr->saddr);
515
516 /* This check is security critical. */
517 if (addrtype == IPV6_ADDR_ANY ||
518 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
519 goto error;
520 if (addrtype & IPV6_ADDR_LINKLOCAL) {
521 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
522 ICMPV6_NOT_NEIGHBOUR, 0);
523 goto error;
524 }
525 }
526
527 mtu = ip6_dst_mtu_forward(dst);
528 if (mtu < IPV6_MIN_MTU)
529 mtu = IPV6_MIN_MTU;
530
531 if (ip6_pkt_too_big(skb, mtu)) {
532 /* Again, force OUTPUT device used as source address */
533 skb->dev = dst->dev;
534 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
535 __IP6_INC_STATS(net, ip6_dst_idev(dst),
536 IPSTATS_MIB_INTOOBIGERRORS);
537 __IP6_INC_STATS(net, ip6_dst_idev(dst),
538 IPSTATS_MIB_FRAGFAILS);
539 kfree_skb(skb);
540 return -EMSGSIZE;
541 }
542
543 if (skb_cow(skb, dst->dev->hard_header_len)) {
544 __IP6_INC_STATS(net, ip6_dst_idev(dst),
545 IPSTATS_MIB_OUTDISCARDS);
546 goto drop;
547 }
548
549 hdr = ipv6_hdr(skb);
550
551 /* Mangling hops number delayed to point after skb COW */
552
553 hdr->hop_limit--;
554
555 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
556 __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
557 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
558 net, NULL, skb, skb->dev, dst->dev,
559 ip6_forward_finish);
560
561 error:
562 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
563 drop:
564 kfree_skb(skb);
565 return -EINVAL;
566 }
567
568 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
569 {
570 to->pkt_type = from->pkt_type;
571 to->priority = from->priority;
572 to->protocol = from->protocol;
573 skb_dst_drop(to);
574 skb_dst_set(to, dst_clone(skb_dst(from)));
575 to->dev = from->dev;
576 to->mark = from->mark;
577
578 #ifdef CONFIG_NET_SCHED
579 to->tc_index = from->tc_index;
580 #endif
581 nf_copy(to, from);
582 skb_copy_secmark(to, from);
583 }
584
585 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
586 int (*output)(struct net *, struct sock *, struct sk_buff *))
587 {
588 struct sk_buff *frag;
589 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
590 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
591 inet6_sk(skb->sk) : NULL;
592 struct ipv6hdr *tmp_hdr;
593 struct frag_hdr *fh;
594 unsigned int mtu, hlen, left, len;
595 int hroom, troom;
596 __be32 frag_id;
597 int ptr, offset = 0, err = 0;
598 u8 *prevhdr, nexthdr = 0;
599
600 err = ip6_find_1stfragopt(skb, &prevhdr);
601 if (err < 0)
602 goto fail;
603 hlen = err;
604 nexthdr = *prevhdr;
605
606 mtu = ip6_skb_dst_mtu(skb);
607
608 /* We must not fragment if the socket is set to force MTU discovery
609 * or if the skb it not generated by a local socket.
610 */
611 if (unlikely(!skb->ignore_df && skb->len > mtu))
612 goto fail_toobig;
613
614 if (IP6CB(skb)->frag_max_size) {
615 if (IP6CB(skb)->frag_max_size > mtu)
616 goto fail_toobig;
617
618 /* don't send fragments larger than what we received */
619 mtu = IP6CB(skb)->frag_max_size;
620 if (mtu < IPV6_MIN_MTU)
621 mtu = IPV6_MIN_MTU;
622 }
623
624 if (np && np->frag_size < mtu) {
625 if (np->frag_size)
626 mtu = np->frag_size;
627 }
628 if (mtu < hlen + sizeof(struct frag_hdr) + 8)
629 goto fail_toobig;
630 mtu -= hlen + sizeof(struct frag_hdr);
631
632 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
633 &ipv6_hdr(skb)->saddr);
634
635 if (skb->ip_summed == CHECKSUM_PARTIAL &&
636 (err = skb_checksum_help(skb)))
637 goto fail;
638
639 hroom = LL_RESERVED_SPACE(rt->dst.dev);
640 if (skb_has_frag_list(skb)) {
641 unsigned int first_len = skb_pagelen(skb);
642 struct sk_buff *frag2;
643
644 if (first_len - hlen > mtu ||
645 ((first_len - hlen) & 7) ||
646 skb_cloned(skb) ||
647 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
648 goto slow_path;
649
650 skb_walk_frags(skb, frag) {
651 /* Correct geometry. */
652 if (frag->len > mtu ||
653 ((frag->len & 7) && frag->next) ||
654 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
655 goto slow_path_clean;
656
657 /* Partially cloned skb? */
658 if (skb_shared(frag))
659 goto slow_path_clean;
660
661 BUG_ON(frag->sk);
662 if (skb->sk) {
663 frag->sk = skb->sk;
664 frag->destructor = sock_wfree;
665 }
666 skb->truesize -= frag->truesize;
667 }
668
669 err = 0;
670 offset = 0;
671 /* BUILD HEADER */
672
673 *prevhdr = NEXTHDR_FRAGMENT;
674 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
675 if (!tmp_hdr) {
676 err = -ENOMEM;
677 goto fail;
678 }
679 frag = skb_shinfo(skb)->frag_list;
680 skb_frag_list_init(skb);
681
682 __skb_pull(skb, hlen);
683 fh = __skb_push(skb, sizeof(struct frag_hdr));
684 __skb_push(skb, hlen);
685 skb_reset_network_header(skb);
686 memcpy(skb_network_header(skb), tmp_hdr, hlen);
687
688 fh->nexthdr = nexthdr;
689 fh->reserved = 0;
690 fh->frag_off = htons(IP6_MF);
691 fh->identification = frag_id;
692
693 first_len = skb_pagelen(skb);
694 skb->data_len = first_len - skb_headlen(skb);
695 skb->len = first_len;
696 ipv6_hdr(skb)->payload_len = htons(first_len -
697 sizeof(struct ipv6hdr));
698
699 for (;;) {
700 /* Prepare header of the next frame,
701 * before previous one went down. */
702 if (frag) {
703 frag->ip_summed = CHECKSUM_NONE;
704 skb_reset_transport_header(frag);
705 fh = __skb_push(frag, sizeof(struct frag_hdr));
706 __skb_push(frag, hlen);
707 skb_reset_network_header(frag);
708 memcpy(skb_network_header(frag), tmp_hdr,
709 hlen);
710 offset += skb->len - hlen - sizeof(struct frag_hdr);
711 fh->nexthdr = nexthdr;
712 fh->reserved = 0;
713 fh->frag_off = htons(offset);
714 if (frag->next)
715 fh->frag_off |= htons(IP6_MF);
716 fh->identification = frag_id;
717 ipv6_hdr(frag)->payload_len =
718 htons(frag->len -
719 sizeof(struct ipv6hdr));
720 ip6_copy_metadata(frag, skb);
721 }
722
723 err = output(net, sk, skb);
724 if (!err)
725 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
726 IPSTATS_MIB_FRAGCREATES);
727
728 if (err || !frag)
729 break;
730
731 skb = frag;
732 frag = skb->next;
733 skb->next = NULL;
734 }
735
736 kfree(tmp_hdr);
737
738 if (err == 0) {
739 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
740 IPSTATS_MIB_FRAGOKS);
741 return 0;
742 }
743
744 kfree_skb_list(frag);
745
746 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
747 IPSTATS_MIB_FRAGFAILS);
748 return err;
749
750 slow_path_clean:
751 skb_walk_frags(skb, frag2) {
752 if (frag2 == frag)
753 break;
754 frag2->sk = NULL;
755 frag2->destructor = NULL;
756 skb->truesize += frag2->truesize;
757 }
758 }
759
760 slow_path:
761 left = skb->len - hlen; /* Space per frame */
762 ptr = hlen; /* Where to start from */
763
764 /*
765 * Fragment the datagram.
766 */
767
768 troom = rt->dst.dev->needed_tailroom;
769
770 /*
771 * Keep copying data until we run out.
772 */
773 while (left > 0) {
774 u8 *fragnexthdr_offset;
775
776 len = left;
777 /* IF: it doesn't fit, use 'mtu' - the data space left */
778 if (len > mtu)
779 len = mtu;
780 /* IF: we are not sending up to and including the packet end
781 then align the next start on an eight byte boundary */
782 if (len < left) {
783 len &= ~7;
784 }
785
786 /* Allocate buffer */
787 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
788 hroom + troom, GFP_ATOMIC);
789 if (!frag) {
790 err = -ENOMEM;
791 goto fail;
792 }
793
794 /*
795 * Set up data on packet
796 */
797
798 ip6_copy_metadata(frag, skb);
799 skb_reserve(frag, hroom);
800 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
801 skb_reset_network_header(frag);
802 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
803 frag->transport_header = (frag->network_header + hlen +
804 sizeof(struct frag_hdr));
805
806 /*
807 * Charge the memory for the fragment to any owner
808 * it might possess
809 */
810 if (skb->sk)
811 skb_set_owner_w(frag, skb->sk);
812
813 /*
814 * Copy the packet header into the new buffer.
815 */
816 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
817
818 fragnexthdr_offset = skb_network_header(frag);
819 fragnexthdr_offset += prevhdr - skb_network_header(skb);
820 *fragnexthdr_offset = NEXTHDR_FRAGMENT;
821
822 /*
823 * Build fragment header.
824 */
825 fh->nexthdr = nexthdr;
826 fh->reserved = 0;
827 fh->identification = frag_id;
828
829 /*
830 * Copy a block of the IP datagram.
831 */
832 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
833 len));
834 left -= len;
835
836 fh->frag_off = htons(offset);
837 if (left > 0)
838 fh->frag_off |= htons(IP6_MF);
839 ipv6_hdr(frag)->payload_len = htons(frag->len -
840 sizeof(struct ipv6hdr));
841
842 ptr += len;
843 offset += len;
844
845 /*
846 * Put this fragment into the sending queue.
847 */
848 err = output(net, sk, frag);
849 if (err)
850 goto fail;
851
852 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
853 IPSTATS_MIB_FRAGCREATES);
854 }
855 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
856 IPSTATS_MIB_FRAGOKS);
857 consume_skb(skb);
858 return err;
859
860 fail_toobig:
861 if (skb->sk && dst_allfrag(skb_dst(skb)))
862 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
863
864 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
865 err = -EMSGSIZE;
866
867 fail:
868 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
869 IPSTATS_MIB_FRAGFAILS);
870 kfree_skb(skb);
871 return err;
872 }
873
874 static inline int ip6_rt_check(const struct rt6key *rt_key,
875 const struct in6_addr *fl_addr,
876 const struct in6_addr *addr_cache)
877 {
878 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
879 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
880 }
881
882 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
883 struct dst_entry *dst,
884 const struct flowi6 *fl6)
885 {
886 struct ipv6_pinfo *np = inet6_sk(sk);
887 struct rt6_info *rt;
888
889 if (!dst)
890 goto out;
891
892 if (dst->ops->family != AF_INET6) {
893 dst_release(dst);
894 return NULL;
895 }
896
897 rt = (struct rt6_info *)dst;
898 /* Yes, checking route validity in not connected
899 * case is not very simple. Take into account,
900 * that we do not support routing by source, TOS,
901 * and MSG_DONTROUTE --ANK (980726)
902 *
903 * 1. ip6_rt_check(): If route was host route,
904 * check that cached destination is current.
905 * If it is network route, we still may
906 * check its validity using saved pointer
907 * to the last used address: daddr_cache.
908 * We do not want to save whole address now,
909 * (because main consumer of this service
910 * is tcp, which has not this problem),
911 * so that the last trick works only on connected
912 * sockets.
913 * 2. oif also should be the same.
914 */
915 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
916 #ifdef CONFIG_IPV6_SUBTREES
917 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
918 #endif
919 (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
920 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
921 dst_release(dst);
922 dst = NULL;
923 }
924
925 out:
926 return dst;
927 }
928
929 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
930 struct dst_entry **dst, struct flowi6 *fl6)
931 {
932 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
933 struct neighbour *n;
934 struct rt6_info *rt;
935 #endif
936 int err;
937 int flags = 0;
938
939 /* The correct way to handle this would be to do
940 * ip6_route_get_saddr, and then ip6_route_output; however,
941 * the route-specific preferred source forces the
942 * ip6_route_output call _before_ ip6_route_get_saddr.
943 *
944 * In source specific routing (no src=any default route),
945 * ip6_route_output will fail given src=any saddr, though, so
946 * that's why we try it again later.
947 */
948 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
949 struct rt6_info *rt;
950 bool had_dst = *dst != NULL;
951
952 if (!had_dst)
953 *dst = ip6_route_output(net, sk, fl6);
954 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
955 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
956 sk ? inet6_sk(sk)->srcprefs : 0,
957 &fl6->saddr);
958 if (err)
959 goto out_err_release;
960
961 /* If we had an erroneous initial result, pretend it
962 * never existed and let the SA-enabled version take
963 * over.
964 */
965 if (!had_dst && (*dst)->error) {
966 dst_release(*dst);
967 *dst = NULL;
968 }
969
970 if (fl6->flowi6_oif)
971 flags |= RT6_LOOKUP_F_IFACE;
972 }
973
974 if (!*dst)
975 *dst = ip6_route_output_flags(net, sk, fl6, flags);
976
977 err = (*dst)->error;
978 if (err)
979 goto out_err_release;
980
981 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
982 /*
983 * Here if the dst entry we've looked up
984 * has a neighbour entry that is in the INCOMPLETE
985 * state and the src address from the flow is
986 * marked as OPTIMISTIC, we release the found
987 * dst entry and replace it instead with the
988 * dst entry of the nexthop router
989 */
990 rt = (struct rt6_info *) *dst;
991 rcu_read_lock_bh();
992 n = __ipv6_neigh_lookup_noref(rt->dst.dev,
993 rt6_nexthop(rt, &fl6->daddr));
994 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
995 rcu_read_unlock_bh();
996
997 if (err) {
998 struct inet6_ifaddr *ifp;
999 struct flowi6 fl_gw6;
1000 int redirect;
1001
1002 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
1003 (*dst)->dev, 1);
1004
1005 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
1006 if (ifp)
1007 in6_ifa_put(ifp);
1008
1009 if (redirect) {
1010 /*
1011 * We need to get the dst entry for the
1012 * default router instead
1013 */
1014 dst_release(*dst);
1015 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1016 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1017 *dst = ip6_route_output(net, sk, &fl_gw6);
1018 err = (*dst)->error;
1019 if (err)
1020 goto out_err_release;
1021 }
1022 }
1023 #endif
1024 if (ipv6_addr_v4mapped(&fl6->saddr) &&
1025 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
1026 err = -EAFNOSUPPORT;
1027 goto out_err_release;
1028 }
1029
1030 return 0;
1031
1032 out_err_release:
1033 dst_release(*dst);
1034 *dst = NULL;
1035
1036 if (err == -ENETUNREACH)
1037 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1038 return err;
1039 }
1040
1041 /**
1042 * ip6_dst_lookup - perform route lookup on flow
1043 * @sk: socket which provides route info
1044 * @dst: pointer to dst_entry * for result
1045 * @fl6: flow to lookup
1046 *
1047 * This function performs a route lookup on the given flow.
1048 *
1049 * It returns zero on success, or a standard errno code on error.
1050 */
1051 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1052 struct flowi6 *fl6)
1053 {
1054 *dst = NULL;
1055 return ip6_dst_lookup_tail(net, sk, dst, fl6);
1056 }
1057 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1058
1059 /**
1060 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1061 * @sk: socket which provides route info
1062 * @fl6: flow to lookup
1063 * @final_dst: final destination address for ipsec lookup
1064 *
1065 * This function performs a route lookup on the given flow.
1066 *
1067 * It returns a valid dst pointer on success, or a pointer encoded
1068 * error code.
1069 */
1070 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1071 const struct in6_addr *final_dst)
1072 {
1073 struct dst_entry *dst = NULL;
1074 int err;
1075
1076 err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1077 if (err)
1078 return ERR_PTR(err);
1079 if (final_dst)
1080 fl6->daddr = *final_dst;
1081
1082 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1083 }
1084 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1085
1086 /**
1087 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1088 * @sk: socket which provides the dst cache and route info
1089 * @fl6: flow to lookup
1090 * @final_dst: final destination address for ipsec lookup
1091 *
1092 * This function performs a route lookup on the given flow with the
1093 * possibility of using the cached route in the socket if it is valid.
1094 * It will take the socket dst lock when operating on the dst cache.
1095 * As a result, this function can only be used in process context.
1096 *
1097 * It returns a valid dst pointer on success, or a pointer encoded
1098 * error code.
1099 */
1100 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1101 const struct in6_addr *final_dst)
1102 {
1103 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1104
1105 dst = ip6_sk_dst_check(sk, dst, fl6);
1106 if (!dst)
1107 dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
1108
1109 return dst;
1110 }
1111 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1112
1113 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1114 gfp_t gfp)
1115 {
1116 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1117 }
1118
1119 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1120 gfp_t gfp)
1121 {
1122 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1123 }
1124
1125 static void ip6_append_data_mtu(unsigned int *mtu,
1126 int *maxfraglen,
1127 unsigned int fragheaderlen,
1128 struct sk_buff *skb,
1129 struct rt6_info *rt,
1130 unsigned int orig_mtu)
1131 {
1132 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1133 if (!skb) {
1134 /* first fragment, reserve header_len */
1135 *mtu = orig_mtu - rt->dst.header_len;
1136
1137 } else {
1138 /*
1139 * this fragment is not first, the headers
1140 * space is regarded as data space.
1141 */
1142 *mtu = orig_mtu;
1143 }
1144 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1145 + fragheaderlen - sizeof(struct frag_hdr);
1146 }
1147 }
1148
1149 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1150 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1151 struct rt6_info *rt, struct flowi6 *fl6)
1152 {
1153 struct ipv6_pinfo *np = inet6_sk(sk);
1154 unsigned int mtu;
1155 struct ipv6_txoptions *opt = ipc6->opt;
1156
1157 /*
1158 * setup for corking
1159 */
1160 if (opt) {
1161 if (WARN_ON(v6_cork->opt))
1162 return -EINVAL;
1163
1164 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1165 if (unlikely(!v6_cork->opt))
1166 return -ENOBUFS;
1167
1168 v6_cork->opt->tot_len = opt->tot_len;
1169 v6_cork->opt->opt_flen = opt->opt_flen;
1170 v6_cork->opt->opt_nflen = opt->opt_nflen;
1171
1172 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1173 sk->sk_allocation);
1174 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1175 return -ENOBUFS;
1176
1177 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1178 sk->sk_allocation);
1179 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1180 return -ENOBUFS;
1181
1182 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1183 sk->sk_allocation);
1184 if (opt->hopopt && !v6_cork->opt->hopopt)
1185 return -ENOBUFS;
1186
1187 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1188 sk->sk_allocation);
1189 if (opt->srcrt && !v6_cork->opt->srcrt)
1190 return -ENOBUFS;
1191
1192 /* need source address above miyazawa*/
1193 }
1194 dst_hold(&rt->dst);
1195 cork->base.dst = &rt->dst;
1196 cork->fl.u.ip6 = *fl6;
1197 v6_cork->hop_limit = ipc6->hlimit;
1198 v6_cork->tclass = ipc6->tclass;
1199 if (rt->dst.flags & DST_XFRM_TUNNEL)
1200 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1201 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1202 else
1203 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1204 rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1205 if (np->frag_size < mtu) {
1206 if (np->frag_size)
1207 mtu = np->frag_size;
1208 }
1209 cork->base.fragsize = mtu;
1210 if (dst_allfrag(rt->dst.path))
1211 cork->base.flags |= IPCORK_ALLFRAG;
1212 cork->base.length = 0;
1213
1214 return 0;
1215 }
1216
1217 static int __ip6_append_data(struct sock *sk,
1218 struct flowi6 *fl6,
1219 struct sk_buff_head *queue,
1220 struct inet_cork *cork,
1221 struct inet6_cork *v6_cork,
1222 struct page_frag *pfrag,
1223 int getfrag(void *from, char *to, int offset,
1224 int len, int odd, struct sk_buff *skb),
1225 void *from, int length, int transhdrlen,
1226 unsigned int flags, struct ipcm6_cookie *ipc6,
1227 const struct sockcm_cookie *sockc)
1228 {
1229 struct sk_buff *skb, *skb_prev = NULL;
1230 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1231 int exthdrlen = 0;
1232 int dst_exthdrlen = 0;
1233 int hh_len;
1234 int copy;
1235 int err;
1236 int offset = 0;
1237 __u8 tx_flags = 0;
1238 u32 tskey = 0;
1239 struct rt6_info *rt = (struct rt6_info *)cork->dst;
1240 struct ipv6_txoptions *opt = v6_cork->opt;
1241 int csummode = CHECKSUM_NONE;
1242 unsigned int maxnonfragsize, headersize;
1243
1244 skb = skb_peek_tail(queue);
1245 if (!skb) {
1246 exthdrlen = opt ? opt->opt_flen : 0;
1247 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1248 }
1249
1250 mtu = cork->fragsize;
1251 orig_mtu = mtu;
1252
1253 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1254
1255 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1256 (opt ? opt->opt_nflen : 0);
1257 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1258 sizeof(struct frag_hdr);
1259
1260 headersize = sizeof(struct ipv6hdr) +
1261 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1262 (dst_allfrag(&rt->dst) ?
1263 sizeof(struct frag_hdr) : 0) +
1264 rt->rt6i_nfheader_len;
1265
1266 if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1267 (sk->sk_protocol == IPPROTO_UDP ||
1268 sk->sk_protocol == IPPROTO_RAW)) {
1269 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1270 sizeof(struct ipv6hdr));
1271 goto emsgsize;
1272 }
1273
1274 if (ip6_sk_ignore_df(sk))
1275 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1276 else
1277 maxnonfragsize = mtu;
1278
1279 if (cork->length + length > maxnonfragsize - headersize) {
1280 emsgsize:
1281 ipv6_local_error(sk, EMSGSIZE, fl6,
1282 mtu - headersize +
1283 sizeof(struct ipv6hdr));
1284 return -EMSGSIZE;
1285 }
1286
1287 /* CHECKSUM_PARTIAL only with no extension headers and when
1288 * we are not going to fragment
1289 */
1290 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1291 headersize == sizeof(struct ipv6hdr) &&
1292 length <= mtu - headersize &&
1293 !(flags & MSG_MORE) &&
1294 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1295 csummode = CHECKSUM_PARTIAL;
1296
1297 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1298 sock_tx_timestamp(sk, sockc->tsflags, &tx_flags);
1299 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1300 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1301 tskey = sk->sk_tskey++;
1302 }
1303
1304 /*
1305 * Let's try using as much space as possible.
1306 * Use MTU if total length of the message fits into the MTU.
1307 * Otherwise, we need to reserve fragment header and
1308 * fragment alignment (= 8-15 octects, in total).
1309 *
1310 * Note that we may need to "move" the data from the tail of
1311 * of the buffer to the new fragment when we split
1312 * the message.
1313 *
1314 * FIXME: It may be fragmented into multiple chunks
1315 * at once if non-fragmentable extension headers
1316 * are too large.
1317 * --yoshfuji
1318 */
1319
1320 cork->length += length;
1321 if (!skb)
1322 goto alloc_new_skb;
1323
1324 while (length > 0) {
1325 /* Check if the remaining data fits into current packet. */
1326 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1327 if (copy < length)
1328 copy = maxfraglen - skb->len;
1329
1330 if (copy <= 0) {
1331 char *data;
1332 unsigned int datalen;
1333 unsigned int fraglen;
1334 unsigned int fraggap;
1335 unsigned int alloclen;
1336 alloc_new_skb:
1337 /* There's no room in the current skb */
1338 if (skb)
1339 fraggap = skb->len - maxfraglen;
1340 else
1341 fraggap = 0;
1342 /* update mtu and maxfraglen if necessary */
1343 if (!skb || !skb_prev)
1344 ip6_append_data_mtu(&mtu, &maxfraglen,
1345 fragheaderlen, skb, rt,
1346 orig_mtu);
1347
1348 skb_prev = skb;
1349
1350 /*
1351 * If remaining data exceeds the mtu,
1352 * we know we need more fragment(s).
1353 */
1354 datalen = length + fraggap;
1355
1356 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1357 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1358 if ((flags & MSG_MORE) &&
1359 !(rt->dst.dev->features&NETIF_F_SG))
1360 alloclen = mtu;
1361 else
1362 alloclen = datalen + fragheaderlen;
1363
1364 alloclen += dst_exthdrlen;
1365
1366 if (datalen != length + fraggap) {
1367 /*
1368 * this is not the last fragment, the trailer
1369 * space is regarded as data space.
1370 */
1371 datalen += rt->dst.trailer_len;
1372 }
1373
1374 alloclen += rt->dst.trailer_len;
1375 fraglen = datalen + fragheaderlen;
1376
1377 /*
1378 * We just reserve space for fragment header.
1379 * Note: this may be overallocation if the message
1380 * (without MSG_MORE) fits into the MTU.
1381 */
1382 alloclen += sizeof(struct frag_hdr);
1383
1384 copy = datalen - transhdrlen - fraggap;
1385 if (copy < 0) {
1386 err = -EINVAL;
1387 goto error;
1388 }
1389 if (transhdrlen) {
1390 skb = sock_alloc_send_skb(sk,
1391 alloclen + hh_len,
1392 (flags & MSG_DONTWAIT), &err);
1393 } else {
1394 skb = NULL;
1395 if (refcount_read(&sk->sk_wmem_alloc) <=
1396 2 * sk->sk_sndbuf)
1397 skb = sock_wmalloc(sk,
1398 alloclen + hh_len, 1,
1399 sk->sk_allocation);
1400 if (unlikely(!skb))
1401 err = -ENOBUFS;
1402 }
1403 if (!skb)
1404 goto error;
1405 /*
1406 * Fill in the control structures
1407 */
1408 skb->protocol = htons(ETH_P_IPV6);
1409 skb->ip_summed = csummode;
1410 skb->csum = 0;
1411 /* reserve for fragmentation and ipsec header */
1412 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1413 dst_exthdrlen);
1414
1415 /* Only the initial fragment is time stamped */
1416 skb_shinfo(skb)->tx_flags = tx_flags;
1417 tx_flags = 0;
1418 skb_shinfo(skb)->tskey = tskey;
1419 tskey = 0;
1420
1421 /*
1422 * Find where to start putting bytes
1423 */
1424 data = skb_put(skb, fraglen);
1425 skb_set_network_header(skb, exthdrlen);
1426 data += fragheaderlen;
1427 skb->transport_header = (skb->network_header +
1428 fragheaderlen);
1429 if (fraggap) {
1430 skb->csum = skb_copy_and_csum_bits(
1431 skb_prev, maxfraglen,
1432 data + transhdrlen, fraggap, 0);
1433 skb_prev->csum = csum_sub(skb_prev->csum,
1434 skb->csum);
1435 data += fraggap;
1436 pskb_trim_unique(skb_prev, maxfraglen);
1437 }
1438 if (copy > 0 &&
1439 getfrag(from, data + transhdrlen, offset,
1440 copy, fraggap, skb) < 0) {
1441 err = -EFAULT;
1442 kfree_skb(skb);
1443 goto error;
1444 }
1445
1446 offset += copy;
1447 length -= datalen - fraggap;
1448 transhdrlen = 0;
1449 exthdrlen = 0;
1450 dst_exthdrlen = 0;
1451
1452 if ((flags & MSG_CONFIRM) && !skb_prev)
1453 skb_set_dst_pending_confirm(skb, 1);
1454
1455 /*
1456 * Put the packet on the pending queue
1457 */
1458 __skb_queue_tail(queue, skb);
1459 continue;
1460 }
1461
1462 if (copy > length)
1463 copy = length;
1464
1465 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1466 unsigned int off;
1467
1468 off = skb->len;
1469 if (getfrag(from, skb_put(skb, copy),
1470 offset, copy, off, skb) < 0) {
1471 __skb_trim(skb, off);
1472 err = -EFAULT;
1473 goto error;
1474 }
1475 } else {
1476 int i = skb_shinfo(skb)->nr_frags;
1477
1478 err = -ENOMEM;
1479 if (!sk_page_frag_refill(sk, pfrag))
1480 goto error;
1481
1482 if (!skb_can_coalesce(skb, i, pfrag->page,
1483 pfrag->offset)) {
1484 err = -EMSGSIZE;
1485 if (i == MAX_SKB_FRAGS)
1486 goto error;
1487
1488 __skb_fill_page_desc(skb, i, pfrag->page,
1489 pfrag->offset, 0);
1490 skb_shinfo(skb)->nr_frags = ++i;
1491 get_page(pfrag->page);
1492 }
1493 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1494 if (getfrag(from,
1495 page_address(pfrag->page) + pfrag->offset,
1496 offset, copy, skb->len, skb) < 0)
1497 goto error_efault;
1498
1499 pfrag->offset += copy;
1500 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1501 skb->len += copy;
1502 skb->data_len += copy;
1503 skb->truesize += copy;
1504 refcount_add(copy, &sk->sk_wmem_alloc);
1505 }
1506 offset += copy;
1507 length -= copy;
1508 }
1509
1510 return 0;
1511
1512 error_efault:
1513 err = -EFAULT;
1514 error:
1515 cork->length -= length;
1516 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1517 return err;
1518 }
1519
1520 int ip6_append_data(struct sock *sk,
1521 int getfrag(void *from, char *to, int offset, int len,
1522 int odd, struct sk_buff *skb),
1523 void *from, int length, int transhdrlen,
1524 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1525 struct rt6_info *rt, unsigned int flags,
1526 const struct sockcm_cookie *sockc)
1527 {
1528 struct inet_sock *inet = inet_sk(sk);
1529 struct ipv6_pinfo *np = inet6_sk(sk);
1530 int exthdrlen;
1531 int err;
1532
1533 if (flags&MSG_PROBE)
1534 return 0;
1535 if (skb_queue_empty(&sk->sk_write_queue)) {
1536 /*
1537 * setup for corking
1538 */
1539 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1540 ipc6, rt, fl6);
1541 if (err)
1542 return err;
1543
1544 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1545 length += exthdrlen;
1546 transhdrlen += exthdrlen;
1547 } else {
1548 fl6 = &inet->cork.fl.u.ip6;
1549 transhdrlen = 0;
1550 }
1551
1552 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1553 &np->cork, sk_page_frag(sk), getfrag,
1554 from, length, transhdrlen, flags, ipc6, sockc);
1555 }
1556 EXPORT_SYMBOL_GPL(ip6_append_data);
1557
1558 static void ip6_cork_release(struct inet_cork_full *cork,
1559 struct inet6_cork *v6_cork)
1560 {
1561 if (v6_cork->opt) {
1562 kfree(v6_cork->opt->dst0opt);
1563 kfree(v6_cork->opt->dst1opt);
1564 kfree(v6_cork->opt->hopopt);
1565 kfree(v6_cork->opt->srcrt);
1566 kfree(v6_cork->opt);
1567 v6_cork->opt = NULL;
1568 }
1569
1570 if (cork->base.dst) {
1571 dst_release(cork->base.dst);
1572 cork->base.dst = NULL;
1573 cork->base.flags &= ~IPCORK_ALLFRAG;
1574 }
1575 memset(&cork->fl, 0, sizeof(cork->fl));
1576 }
1577
1578 struct sk_buff *__ip6_make_skb(struct sock *sk,
1579 struct sk_buff_head *queue,
1580 struct inet_cork_full *cork,
1581 struct inet6_cork *v6_cork)
1582 {
1583 struct sk_buff *skb, *tmp_skb;
1584 struct sk_buff **tail_skb;
1585 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1586 struct ipv6_pinfo *np = inet6_sk(sk);
1587 struct net *net = sock_net(sk);
1588 struct ipv6hdr *hdr;
1589 struct ipv6_txoptions *opt = v6_cork->opt;
1590 struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1591 struct flowi6 *fl6 = &cork->fl.u.ip6;
1592 unsigned char proto = fl6->flowi6_proto;
1593
1594 skb = __skb_dequeue(queue);
1595 if (!skb)
1596 goto out;
1597 tail_skb = &(skb_shinfo(skb)->frag_list);
1598
1599 /* move skb->data to ip header from ext header */
1600 if (skb->data < skb_network_header(skb))
1601 __skb_pull(skb, skb_network_offset(skb));
1602 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1603 __skb_pull(tmp_skb, skb_network_header_len(skb));
1604 *tail_skb = tmp_skb;
1605 tail_skb = &(tmp_skb->next);
1606 skb->len += tmp_skb->len;
1607 skb->data_len += tmp_skb->len;
1608 skb->truesize += tmp_skb->truesize;
1609 tmp_skb->destructor = NULL;
1610 tmp_skb->sk = NULL;
1611 }
1612
1613 /* Allow local fragmentation. */
1614 skb->ignore_df = ip6_sk_ignore_df(sk);
1615
1616 *final_dst = fl6->daddr;
1617 __skb_pull(skb, skb_network_header_len(skb));
1618 if (opt && opt->opt_flen)
1619 ipv6_push_frag_opts(skb, opt, &proto);
1620 if (opt && opt->opt_nflen)
1621 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1622
1623 skb_push(skb, sizeof(struct ipv6hdr));
1624 skb_reset_network_header(skb);
1625 hdr = ipv6_hdr(skb);
1626
1627 ip6_flow_hdr(hdr, v6_cork->tclass,
1628 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1629 np->autoflowlabel, fl6));
1630 hdr->hop_limit = v6_cork->hop_limit;
1631 hdr->nexthdr = proto;
1632 hdr->saddr = fl6->saddr;
1633 hdr->daddr = *final_dst;
1634
1635 skb->priority = sk->sk_priority;
1636 skb->mark = sk->sk_mark;
1637
1638 skb_dst_set(skb, dst_clone(&rt->dst));
1639 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1640 if (proto == IPPROTO_ICMPV6) {
1641 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1642
1643 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1644 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1645 }
1646
1647 ip6_cork_release(cork, v6_cork);
1648 out:
1649 return skb;
1650 }
1651
1652 int ip6_send_skb(struct sk_buff *skb)
1653 {
1654 struct net *net = sock_net(skb->sk);
1655 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1656 int err;
1657
1658 err = ip6_local_out(net, skb->sk, skb);
1659 if (err) {
1660 if (err > 0)
1661 err = net_xmit_errno(err);
1662 if (err)
1663 IP6_INC_STATS(net, rt->rt6i_idev,
1664 IPSTATS_MIB_OUTDISCARDS);
1665 }
1666
1667 return err;
1668 }
1669
1670 int ip6_push_pending_frames(struct sock *sk)
1671 {
1672 struct sk_buff *skb;
1673
1674 skb = ip6_finish_skb(sk);
1675 if (!skb)
1676 return 0;
1677
1678 return ip6_send_skb(skb);
1679 }
1680 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1681
1682 static void __ip6_flush_pending_frames(struct sock *sk,
1683 struct sk_buff_head *queue,
1684 struct inet_cork_full *cork,
1685 struct inet6_cork *v6_cork)
1686 {
1687 struct sk_buff *skb;
1688
1689 while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1690 if (skb_dst(skb))
1691 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1692 IPSTATS_MIB_OUTDISCARDS);
1693 kfree_skb(skb);
1694 }
1695
1696 ip6_cork_release(cork, v6_cork);
1697 }
1698
1699 void ip6_flush_pending_frames(struct sock *sk)
1700 {
1701 __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1702 &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1703 }
1704 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1705
1706 struct sk_buff *ip6_make_skb(struct sock *sk,
1707 int getfrag(void *from, char *to, int offset,
1708 int len, int odd, struct sk_buff *skb),
1709 void *from, int length, int transhdrlen,
1710 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1711 struct rt6_info *rt, unsigned int flags,
1712 const struct sockcm_cookie *sockc)
1713 {
1714 struct inet_cork_full cork;
1715 struct inet6_cork v6_cork;
1716 struct sk_buff_head queue;
1717 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1718 int err;
1719
1720 if (flags & MSG_PROBE)
1721 return NULL;
1722
1723 __skb_queue_head_init(&queue);
1724
1725 cork.base.flags = 0;
1726 cork.base.addr = 0;
1727 cork.base.opt = NULL;
1728 v6_cork.opt = NULL;
1729 err = ip6_setup_cork(sk, &cork, &v6_cork, ipc6, rt, fl6);
1730 if (err)
1731 return ERR_PTR(err);
1732
1733 if (ipc6->dontfrag < 0)
1734 ipc6->dontfrag = inet6_sk(sk)->dontfrag;
1735
1736 err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
1737 &current->task_frag, getfrag, from,
1738 length + exthdrlen, transhdrlen + exthdrlen,
1739 flags, ipc6, sockc);
1740 if (err) {
1741 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
1742 return ERR_PTR(err);
1743 }
1744
1745 return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
1746 }
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