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[mirror_ubuntu-artful-kernel.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/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 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
677 IPSTATS_MIB_FRAGFAILS);
678 err = -ENOMEM;
679 goto fail;
680 }
681 frag = skb_shinfo(skb)->frag_list;
682 skb_frag_list_init(skb);
683
684 __skb_pull(skb, hlen);
685 fh = __skb_push(skb, sizeof(struct frag_hdr));
686 __skb_push(skb, hlen);
687 skb_reset_network_header(skb);
688 memcpy(skb_network_header(skb), tmp_hdr, hlen);
689
690 fh->nexthdr = nexthdr;
691 fh->reserved = 0;
692 fh->frag_off = htons(IP6_MF);
693 fh->identification = frag_id;
694
695 first_len = skb_pagelen(skb);
696 skb->data_len = first_len - skb_headlen(skb);
697 skb->len = first_len;
698 ipv6_hdr(skb)->payload_len = htons(first_len -
699 sizeof(struct ipv6hdr));
700
701 for (;;) {
702 /* Prepare header of the next frame,
703 * before previous one went down. */
704 if (frag) {
705 frag->ip_summed = CHECKSUM_NONE;
706 skb_reset_transport_header(frag);
707 fh = __skb_push(frag, sizeof(struct frag_hdr));
708 __skb_push(frag, hlen);
709 skb_reset_network_header(frag);
710 memcpy(skb_network_header(frag), tmp_hdr,
711 hlen);
712 offset += skb->len - hlen - sizeof(struct frag_hdr);
713 fh->nexthdr = nexthdr;
714 fh->reserved = 0;
715 fh->frag_off = htons(offset);
716 if (frag->next)
717 fh->frag_off |= htons(IP6_MF);
718 fh->identification = frag_id;
719 ipv6_hdr(frag)->payload_len =
720 htons(frag->len -
721 sizeof(struct ipv6hdr));
722 ip6_copy_metadata(frag, skb);
723 }
724
725 err = output(net, sk, skb);
726 if (!err)
727 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
728 IPSTATS_MIB_FRAGCREATES);
729
730 if (err || !frag)
731 break;
732
733 skb = frag;
734 frag = skb->next;
735 skb->next = NULL;
736 }
737
738 kfree(tmp_hdr);
739
740 if (err == 0) {
741 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
742 IPSTATS_MIB_FRAGOKS);
743 return 0;
744 }
745
746 kfree_skb_list(frag);
747
748 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
749 IPSTATS_MIB_FRAGFAILS);
750 return err;
751
752 slow_path_clean:
753 skb_walk_frags(skb, frag2) {
754 if (frag2 == frag)
755 break;
756 frag2->sk = NULL;
757 frag2->destructor = NULL;
758 skb->truesize += frag2->truesize;
759 }
760 }
761
762 slow_path:
763 left = skb->len - hlen; /* Space per frame */
764 ptr = hlen; /* Where to start from */
765
766 /*
767 * Fragment the datagram.
768 */
769
770 troom = rt->dst.dev->needed_tailroom;
771
772 /*
773 * Keep copying data until we run out.
774 */
775 while (left > 0) {
776 u8 *fragnexthdr_offset;
777
778 len = left;
779 /* IF: it doesn't fit, use 'mtu' - the data space left */
780 if (len > mtu)
781 len = mtu;
782 /* IF: we are not sending up to and including the packet end
783 then align the next start on an eight byte boundary */
784 if (len < left) {
785 len &= ~7;
786 }
787
788 /* Allocate buffer */
789 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
790 hroom + troom, GFP_ATOMIC);
791 if (!frag) {
792 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
793 IPSTATS_MIB_FRAGFAILS);
794 err = -ENOMEM;
795 goto fail;
796 }
797
798 /*
799 * Set up data on packet
800 */
801
802 ip6_copy_metadata(frag, skb);
803 skb_reserve(frag, hroom);
804 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
805 skb_reset_network_header(frag);
806 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
807 frag->transport_header = (frag->network_header + hlen +
808 sizeof(struct frag_hdr));
809
810 /*
811 * Charge the memory for the fragment to any owner
812 * it might possess
813 */
814 if (skb->sk)
815 skb_set_owner_w(frag, skb->sk);
816
817 /*
818 * Copy the packet header into the new buffer.
819 */
820 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
821
822 fragnexthdr_offset = skb_network_header(frag);
823 fragnexthdr_offset += prevhdr - skb_network_header(skb);
824 *fragnexthdr_offset = NEXTHDR_FRAGMENT;
825
826 /*
827 * Build fragment header.
828 */
829 fh->nexthdr = nexthdr;
830 fh->reserved = 0;
831 fh->identification = frag_id;
832
833 /*
834 * Copy a block of the IP datagram.
835 */
836 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
837 len));
838 left -= len;
839
840 fh->frag_off = htons(offset);
841 if (left > 0)
842 fh->frag_off |= htons(IP6_MF);
843 ipv6_hdr(frag)->payload_len = htons(frag->len -
844 sizeof(struct ipv6hdr));
845
846 ptr += len;
847 offset += len;
848
849 /*
850 * Put this fragment into the sending queue.
851 */
852 err = output(net, sk, frag);
853 if (err)
854 goto fail;
855
856 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
857 IPSTATS_MIB_FRAGCREATES);
858 }
859 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
860 IPSTATS_MIB_FRAGOKS);
861 consume_skb(skb);
862 return err;
863
864 fail_toobig:
865 if (skb->sk && dst_allfrag(skb_dst(skb)))
866 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
867
868 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
869 err = -EMSGSIZE;
870
871 fail:
872 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
873 IPSTATS_MIB_FRAGFAILS);
874 kfree_skb(skb);
875 return err;
876 }
877
878 static inline int ip6_rt_check(const struct rt6key *rt_key,
879 const struct in6_addr *fl_addr,
880 const struct in6_addr *addr_cache)
881 {
882 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
883 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
884 }
885
886 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
887 struct dst_entry *dst,
888 const struct flowi6 *fl6)
889 {
890 struct ipv6_pinfo *np = inet6_sk(sk);
891 struct rt6_info *rt;
892
893 if (!dst)
894 goto out;
895
896 if (dst->ops->family != AF_INET6) {
897 dst_release(dst);
898 return NULL;
899 }
900
901 rt = (struct rt6_info *)dst;
902 /* Yes, checking route validity in not connected
903 * case is not very simple. Take into account,
904 * that we do not support routing by source, TOS,
905 * and MSG_DONTROUTE --ANK (980726)
906 *
907 * 1. ip6_rt_check(): If route was host route,
908 * check that cached destination is current.
909 * If it is network route, we still may
910 * check its validity using saved pointer
911 * to the last used address: daddr_cache.
912 * We do not want to save whole address now,
913 * (because main consumer of this service
914 * is tcp, which has not this problem),
915 * so that the last trick works only on connected
916 * sockets.
917 * 2. oif also should be the same.
918 */
919 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
920 #ifdef CONFIG_IPV6_SUBTREES
921 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
922 #endif
923 (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
924 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
925 dst_release(dst);
926 dst = NULL;
927 }
928
929 out:
930 return dst;
931 }
932
933 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
934 struct dst_entry **dst, struct flowi6 *fl6)
935 {
936 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
937 struct neighbour *n;
938 struct rt6_info *rt;
939 #endif
940 int err;
941 int flags = 0;
942
943 /* The correct way to handle this would be to do
944 * ip6_route_get_saddr, and then ip6_route_output; however,
945 * the route-specific preferred source forces the
946 * ip6_route_output call _before_ ip6_route_get_saddr.
947 *
948 * In source specific routing (no src=any default route),
949 * ip6_route_output will fail given src=any saddr, though, so
950 * that's why we try it again later.
951 */
952 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
953 struct rt6_info *rt;
954 bool had_dst = *dst != NULL;
955
956 if (!had_dst)
957 *dst = ip6_route_output(net, sk, fl6);
958 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
959 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
960 sk ? inet6_sk(sk)->srcprefs : 0,
961 &fl6->saddr);
962 if (err)
963 goto out_err_release;
964
965 /* If we had an erroneous initial result, pretend it
966 * never existed and let the SA-enabled version take
967 * over.
968 */
969 if (!had_dst && (*dst)->error) {
970 dst_release(*dst);
971 *dst = NULL;
972 }
973
974 if (fl6->flowi6_oif)
975 flags |= RT6_LOOKUP_F_IFACE;
976 }
977
978 if (!*dst)
979 *dst = ip6_route_output_flags(net, sk, fl6, flags);
980
981 err = (*dst)->error;
982 if (err)
983 goto out_err_release;
984
985 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
986 /*
987 * Here if the dst entry we've looked up
988 * has a neighbour entry that is in the INCOMPLETE
989 * state and the src address from the flow is
990 * marked as OPTIMISTIC, we release the found
991 * dst entry and replace it instead with the
992 * dst entry of the nexthop router
993 */
994 rt = (struct rt6_info *) *dst;
995 rcu_read_lock_bh();
996 n = __ipv6_neigh_lookup_noref(rt->dst.dev,
997 rt6_nexthop(rt, &fl6->daddr));
998 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
999 rcu_read_unlock_bh();
1000
1001 if (err) {
1002 struct inet6_ifaddr *ifp;
1003 struct flowi6 fl_gw6;
1004 int redirect;
1005
1006 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
1007 (*dst)->dev, 1);
1008
1009 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
1010 if (ifp)
1011 in6_ifa_put(ifp);
1012
1013 if (redirect) {
1014 /*
1015 * We need to get the dst entry for the
1016 * default router instead
1017 */
1018 dst_release(*dst);
1019 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1020 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1021 *dst = ip6_route_output(net, sk, &fl_gw6);
1022 err = (*dst)->error;
1023 if (err)
1024 goto out_err_release;
1025 }
1026 }
1027 #endif
1028 if (ipv6_addr_v4mapped(&fl6->saddr) &&
1029 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
1030 err = -EAFNOSUPPORT;
1031 goto out_err_release;
1032 }
1033
1034 return 0;
1035
1036 out_err_release:
1037 dst_release(*dst);
1038 *dst = NULL;
1039
1040 if (err == -ENETUNREACH)
1041 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1042 return err;
1043 }
1044
1045 /**
1046 * ip6_dst_lookup - perform route lookup on flow
1047 * @sk: socket which provides route info
1048 * @dst: pointer to dst_entry * for result
1049 * @fl6: flow to lookup
1050 *
1051 * This function performs a route lookup on the given flow.
1052 *
1053 * It returns zero on success, or a standard errno code on error.
1054 */
1055 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1056 struct flowi6 *fl6)
1057 {
1058 *dst = NULL;
1059 return ip6_dst_lookup_tail(net, sk, dst, fl6);
1060 }
1061 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1062
1063 /**
1064 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1065 * @sk: socket which provides route info
1066 * @fl6: flow to lookup
1067 * @final_dst: final destination address for ipsec lookup
1068 *
1069 * This function performs a route lookup on the given flow.
1070 *
1071 * It returns a valid dst pointer on success, or a pointer encoded
1072 * error code.
1073 */
1074 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1075 const struct in6_addr *final_dst)
1076 {
1077 struct dst_entry *dst = NULL;
1078 int err;
1079
1080 err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1081 if (err)
1082 return ERR_PTR(err);
1083 if (final_dst)
1084 fl6->daddr = *final_dst;
1085
1086 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1087 }
1088 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1089
1090 /**
1091 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1092 * @sk: socket which provides the dst cache and route info
1093 * @fl6: flow to lookup
1094 * @final_dst: final destination address for ipsec lookup
1095 *
1096 * This function performs a route lookup on the given flow with the
1097 * possibility of using the cached route in the socket if it is valid.
1098 * It will take the socket dst lock when operating on the dst cache.
1099 * As a result, this function can only be used in process context.
1100 *
1101 * It returns a valid dst pointer on success, or a pointer encoded
1102 * error code.
1103 */
1104 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1105 const struct in6_addr *final_dst)
1106 {
1107 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1108
1109 dst = ip6_sk_dst_check(sk, dst, fl6);
1110 if (!dst)
1111 dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
1112
1113 return dst;
1114 }
1115 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1116
1117 static inline int ip6_ufo_append_data(struct sock *sk,
1118 struct sk_buff_head *queue,
1119 int getfrag(void *from, char *to, int offset, int len,
1120 int odd, struct sk_buff *skb),
1121 void *from, int length, int hh_len, int fragheaderlen,
1122 int exthdrlen, int transhdrlen, int mtu,
1123 unsigned int flags, const struct flowi6 *fl6)
1124
1125 {
1126 struct sk_buff *skb;
1127 int err;
1128
1129 /* There is support for UDP large send offload by network
1130 * device, so create one single skb packet containing complete
1131 * udp datagram
1132 */
1133 skb = skb_peek_tail(queue);
1134 if (!skb) {
1135 skb = sock_alloc_send_skb(sk,
1136 hh_len + fragheaderlen + transhdrlen + 20,
1137 (flags & MSG_DONTWAIT), &err);
1138 if (!skb)
1139 return err;
1140
1141 /* reserve space for Hardware header */
1142 skb_reserve(skb, hh_len);
1143
1144 /* create space for UDP/IP header */
1145 skb_put(skb, fragheaderlen + transhdrlen);
1146
1147 /* initialize network header pointer */
1148 skb_set_network_header(skb, exthdrlen);
1149
1150 /* initialize protocol header pointer */
1151 skb->transport_header = skb->network_header + fragheaderlen;
1152
1153 skb->protocol = htons(ETH_P_IPV6);
1154 skb->csum = 0;
1155
1156 if (flags & MSG_CONFIRM)
1157 skb_set_dst_pending_confirm(skb, 1);
1158
1159 __skb_queue_tail(queue, skb);
1160 } else if (skb_is_gso(skb)) {
1161 goto append;
1162 }
1163
1164 skb->ip_summed = CHECKSUM_PARTIAL;
1165 /* Specify the length of each IPv6 datagram fragment.
1166 * It has to be a multiple of 8.
1167 */
1168 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1169 sizeof(struct frag_hdr)) & ~7;
1170 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1171 skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk),
1172 &fl6->daddr,
1173 &fl6->saddr);
1174
1175 append:
1176 return skb_append_datato_frags(sk, skb, getfrag, from,
1177 (length - transhdrlen));
1178 }
1179
1180 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1181 gfp_t gfp)
1182 {
1183 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1184 }
1185
1186 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1187 gfp_t gfp)
1188 {
1189 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1190 }
1191
1192 static void ip6_append_data_mtu(unsigned int *mtu,
1193 int *maxfraglen,
1194 unsigned int fragheaderlen,
1195 struct sk_buff *skb,
1196 struct rt6_info *rt,
1197 unsigned int orig_mtu)
1198 {
1199 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1200 if (!skb) {
1201 /* first fragment, reserve header_len */
1202 *mtu = orig_mtu - rt->dst.header_len;
1203
1204 } else {
1205 /*
1206 * this fragment is not first, the headers
1207 * space is regarded as data space.
1208 */
1209 *mtu = orig_mtu;
1210 }
1211 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1212 + fragheaderlen - sizeof(struct frag_hdr);
1213 }
1214 }
1215
1216 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1217 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1218 struct rt6_info *rt, struct flowi6 *fl6)
1219 {
1220 struct ipv6_pinfo *np = inet6_sk(sk);
1221 unsigned int mtu;
1222 struct ipv6_txoptions *opt = ipc6->opt;
1223
1224 /*
1225 * setup for corking
1226 */
1227 if (opt) {
1228 if (WARN_ON(v6_cork->opt))
1229 return -EINVAL;
1230
1231 v6_cork->opt = kzalloc(opt->tot_len, sk->sk_allocation);
1232 if (unlikely(!v6_cork->opt))
1233 return -ENOBUFS;
1234
1235 v6_cork->opt->tot_len = opt->tot_len;
1236 v6_cork->opt->opt_flen = opt->opt_flen;
1237 v6_cork->opt->opt_nflen = opt->opt_nflen;
1238
1239 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1240 sk->sk_allocation);
1241 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1242 return -ENOBUFS;
1243
1244 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1245 sk->sk_allocation);
1246 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1247 return -ENOBUFS;
1248
1249 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1250 sk->sk_allocation);
1251 if (opt->hopopt && !v6_cork->opt->hopopt)
1252 return -ENOBUFS;
1253
1254 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1255 sk->sk_allocation);
1256 if (opt->srcrt && !v6_cork->opt->srcrt)
1257 return -ENOBUFS;
1258
1259 /* need source address above miyazawa*/
1260 }
1261 dst_hold(&rt->dst);
1262 cork->base.dst = &rt->dst;
1263 cork->fl.u.ip6 = *fl6;
1264 v6_cork->hop_limit = ipc6->hlimit;
1265 v6_cork->tclass = ipc6->tclass;
1266 if (rt->dst.flags & DST_XFRM_TUNNEL)
1267 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1268 rt->dst.dev->mtu : dst_mtu(&rt->dst);
1269 else
1270 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1271 rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1272 if (np->frag_size < mtu) {
1273 if (np->frag_size)
1274 mtu = np->frag_size;
1275 }
1276 cork->base.fragsize = mtu;
1277 if (dst_allfrag(rt->dst.path))
1278 cork->base.flags |= IPCORK_ALLFRAG;
1279 cork->base.length = 0;
1280
1281 return 0;
1282 }
1283
1284 static int __ip6_append_data(struct sock *sk,
1285 struct flowi6 *fl6,
1286 struct sk_buff_head *queue,
1287 struct inet_cork *cork,
1288 struct inet6_cork *v6_cork,
1289 struct page_frag *pfrag,
1290 int getfrag(void *from, char *to, int offset,
1291 int len, int odd, struct sk_buff *skb),
1292 void *from, int length, int transhdrlen,
1293 unsigned int flags, struct ipcm6_cookie *ipc6,
1294 const struct sockcm_cookie *sockc)
1295 {
1296 struct sk_buff *skb, *skb_prev = NULL;
1297 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu;
1298 int exthdrlen = 0;
1299 int dst_exthdrlen = 0;
1300 int hh_len;
1301 int copy;
1302 int err;
1303 int offset = 0;
1304 __u8 tx_flags = 0;
1305 u32 tskey = 0;
1306 struct rt6_info *rt = (struct rt6_info *)cork->dst;
1307 struct ipv6_txoptions *opt = v6_cork->opt;
1308 int csummode = CHECKSUM_NONE;
1309 unsigned int maxnonfragsize, headersize;
1310
1311 skb = skb_peek_tail(queue);
1312 if (!skb) {
1313 exthdrlen = opt ? opt->opt_flen : 0;
1314 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1315 }
1316
1317 mtu = cork->fragsize;
1318 orig_mtu = mtu;
1319
1320 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1321
1322 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1323 (opt ? opt->opt_nflen : 0);
1324 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1325 sizeof(struct frag_hdr);
1326
1327 headersize = sizeof(struct ipv6hdr) +
1328 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1329 (dst_allfrag(&rt->dst) ?
1330 sizeof(struct frag_hdr) : 0) +
1331 rt->rt6i_nfheader_len;
1332
1333 if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1334 (sk->sk_protocol == IPPROTO_UDP ||
1335 sk->sk_protocol == IPPROTO_RAW)) {
1336 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1337 sizeof(struct ipv6hdr));
1338 goto emsgsize;
1339 }
1340
1341 if (ip6_sk_ignore_df(sk))
1342 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1343 else
1344 maxnonfragsize = mtu;
1345
1346 if (cork->length + length > maxnonfragsize - headersize) {
1347 emsgsize:
1348 ipv6_local_error(sk, EMSGSIZE, fl6,
1349 mtu - headersize +
1350 sizeof(struct ipv6hdr));
1351 return -EMSGSIZE;
1352 }
1353
1354 /* CHECKSUM_PARTIAL only with no extension headers and when
1355 * we are not going to fragment
1356 */
1357 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1358 headersize == sizeof(struct ipv6hdr) &&
1359 length <= mtu - headersize &&
1360 !(flags & MSG_MORE) &&
1361 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1362 csummode = CHECKSUM_PARTIAL;
1363
1364 if (sk->sk_type == SOCK_DGRAM || sk->sk_type == SOCK_RAW) {
1365 sock_tx_timestamp(sk, sockc->tsflags, &tx_flags);
1366 if (tx_flags & SKBTX_ANY_SW_TSTAMP &&
1367 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1368 tskey = sk->sk_tskey++;
1369 }
1370
1371 /*
1372 * Let's try using as much space as possible.
1373 * Use MTU if total length of the message fits into the MTU.
1374 * Otherwise, we need to reserve fragment header and
1375 * fragment alignment (= 8-15 octects, in total).
1376 *
1377 * Note that we may need to "move" the data from the tail of
1378 * of the buffer to the new fragment when we split
1379 * the message.
1380 *
1381 * FIXME: It may be fragmented into multiple chunks
1382 * at once if non-fragmentable extension headers
1383 * are too large.
1384 * --yoshfuji
1385 */
1386
1387 cork->length += length;
1388 if ((((length + (skb ? skb->len : headersize)) > mtu) ||
1389 (skb && skb_is_gso(skb))) &&
1390 (sk->sk_protocol == IPPROTO_UDP) &&
1391 (rt->dst.dev->features & NETIF_F_UFO) && !dst_xfrm(&rt->dst) &&
1392 (sk->sk_type == SOCK_DGRAM) && !udp_get_no_check6_tx(sk)) {
1393 err = ip6_ufo_append_data(sk, queue, getfrag, from, length,
1394 hh_len, fragheaderlen, exthdrlen,
1395 transhdrlen, mtu, flags, fl6);
1396 if (err)
1397 goto error;
1398 return 0;
1399 }
1400
1401 if (!skb)
1402 goto alloc_new_skb;
1403
1404 while (length > 0) {
1405 /* Check if the remaining data fits into current packet. */
1406 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1407 if (copy < length)
1408 copy = maxfraglen - skb->len;
1409
1410 if (copy <= 0) {
1411 char *data;
1412 unsigned int datalen;
1413 unsigned int fraglen;
1414 unsigned int fraggap;
1415 unsigned int alloclen;
1416 alloc_new_skb:
1417 /* There's no room in the current skb */
1418 if (skb)
1419 fraggap = skb->len - maxfraglen;
1420 else
1421 fraggap = 0;
1422 /* update mtu and maxfraglen if necessary */
1423 if (!skb || !skb_prev)
1424 ip6_append_data_mtu(&mtu, &maxfraglen,
1425 fragheaderlen, skb, rt,
1426 orig_mtu);
1427
1428 skb_prev = skb;
1429
1430 /*
1431 * If remaining data exceeds the mtu,
1432 * we know we need more fragment(s).
1433 */
1434 datalen = length + fraggap;
1435
1436 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1437 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1438 if ((flags & MSG_MORE) &&
1439 !(rt->dst.dev->features&NETIF_F_SG))
1440 alloclen = mtu;
1441 else
1442 alloclen = datalen + fragheaderlen;
1443
1444 alloclen += dst_exthdrlen;
1445
1446 if (datalen != length + fraggap) {
1447 /*
1448 * this is not the last fragment, the trailer
1449 * space is regarded as data space.
1450 */
1451 datalen += rt->dst.trailer_len;
1452 }
1453
1454 alloclen += rt->dst.trailer_len;
1455 fraglen = datalen + fragheaderlen;
1456
1457 /*
1458 * We just reserve space for fragment header.
1459 * Note: this may be overallocation if the message
1460 * (without MSG_MORE) fits into the MTU.
1461 */
1462 alloclen += sizeof(struct frag_hdr);
1463
1464 copy = datalen - transhdrlen - fraggap;
1465 if (copy < 0) {
1466 err = -EINVAL;
1467 goto error;
1468 }
1469 if (transhdrlen) {
1470 skb = sock_alloc_send_skb(sk,
1471 alloclen + hh_len,
1472 (flags & MSG_DONTWAIT), &err);
1473 } else {
1474 skb = NULL;
1475 if (refcount_read(&sk->sk_wmem_alloc) <=
1476 2 * sk->sk_sndbuf)
1477 skb = sock_wmalloc(sk,
1478 alloclen + hh_len, 1,
1479 sk->sk_allocation);
1480 if (unlikely(!skb))
1481 err = -ENOBUFS;
1482 }
1483 if (!skb)
1484 goto error;
1485 /*
1486 * Fill in the control structures
1487 */
1488 skb->protocol = htons(ETH_P_IPV6);
1489 skb->ip_summed = csummode;
1490 skb->csum = 0;
1491 /* reserve for fragmentation and ipsec header */
1492 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1493 dst_exthdrlen);
1494
1495 /* Only the initial fragment is time stamped */
1496 skb_shinfo(skb)->tx_flags = tx_flags;
1497 tx_flags = 0;
1498 skb_shinfo(skb)->tskey = tskey;
1499 tskey = 0;
1500
1501 /*
1502 * Find where to start putting bytes
1503 */
1504 data = skb_put(skb, fraglen);
1505 skb_set_network_header(skb, exthdrlen);
1506 data += fragheaderlen;
1507 skb->transport_header = (skb->network_header +
1508 fragheaderlen);
1509 if (fraggap) {
1510 skb->csum = skb_copy_and_csum_bits(
1511 skb_prev, maxfraglen,
1512 data + transhdrlen, fraggap, 0);
1513 skb_prev->csum = csum_sub(skb_prev->csum,
1514 skb->csum);
1515 data += fraggap;
1516 pskb_trim_unique(skb_prev, maxfraglen);
1517 }
1518 if (copy > 0 &&
1519 getfrag(from, data + transhdrlen, offset,
1520 copy, fraggap, skb) < 0) {
1521 err = -EFAULT;
1522 kfree_skb(skb);
1523 goto error;
1524 }
1525
1526 offset += copy;
1527 length -= datalen - fraggap;
1528 transhdrlen = 0;
1529 exthdrlen = 0;
1530 dst_exthdrlen = 0;
1531
1532 if ((flags & MSG_CONFIRM) && !skb_prev)
1533 skb_set_dst_pending_confirm(skb, 1);
1534
1535 /*
1536 * Put the packet on the pending queue
1537 */
1538 __skb_queue_tail(queue, skb);
1539 continue;
1540 }
1541
1542 if (copy > length)
1543 copy = length;
1544
1545 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1546 unsigned int off;
1547
1548 off = skb->len;
1549 if (getfrag(from, skb_put(skb, copy),
1550 offset, copy, off, skb) < 0) {
1551 __skb_trim(skb, off);
1552 err = -EFAULT;
1553 goto error;
1554 }
1555 } else {
1556 int i = skb_shinfo(skb)->nr_frags;
1557
1558 err = -ENOMEM;
1559 if (!sk_page_frag_refill(sk, pfrag))
1560 goto error;
1561
1562 if (!skb_can_coalesce(skb, i, pfrag->page,
1563 pfrag->offset)) {
1564 err = -EMSGSIZE;
1565 if (i == MAX_SKB_FRAGS)
1566 goto error;
1567
1568 __skb_fill_page_desc(skb, i, pfrag->page,
1569 pfrag->offset, 0);
1570 skb_shinfo(skb)->nr_frags = ++i;
1571 get_page(pfrag->page);
1572 }
1573 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1574 if (getfrag(from,
1575 page_address(pfrag->page) + pfrag->offset,
1576 offset, copy, skb->len, skb) < 0)
1577 goto error_efault;
1578
1579 pfrag->offset += copy;
1580 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1581 skb->len += copy;
1582 skb->data_len += copy;
1583 skb->truesize += copy;
1584 refcount_add(copy, &sk->sk_wmem_alloc);
1585 }
1586 offset += copy;
1587 length -= copy;
1588 }
1589
1590 return 0;
1591
1592 error_efault:
1593 err = -EFAULT;
1594 error:
1595 cork->length -= length;
1596 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1597 return err;
1598 }
1599
1600 int ip6_append_data(struct sock *sk,
1601 int getfrag(void *from, char *to, int offset, int len,
1602 int odd, struct sk_buff *skb),
1603 void *from, int length, int transhdrlen,
1604 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1605 struct rt6_info *rt, unsigned int flags,
1606 const struct sockcm_cookie *sockc)
1607 {
1608 struct inet_sock *inet = inet_sk(sk);
1609 struct ipv6_pinfo *np = inet6_sk(sk);
1610 int exthdrlen;
1611 int err;
1612
1613 if (flags&MSG_PROBE)
1614 return 0;
1615 if (skb_queue_empty(&sk->sk_write_queue)) {
1616 /*
1617 * setup for corking
1618 */
1619 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1620 ipc6, rt, fl6);
1621 if (err)
1622 return err;
1623
1624 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1625 length += exthdrlen;
1626 transhdrlen += exthdrlen;
1627 } else {
1628 fl6 = &inet->cork.fl.u.ip6;
1629 transhdrlen = 0;
1630 }
1631
1632 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1633 &np->cork, sk_page_frag(sk), getfrag,
1634 from, length, transhdrlen, flags, ipc6, sockc);
1635 }
1636 EXPORT_SYMBOL_GPL(ip6_append_data);
1637
1638 static void ip6_cork_release(struct inet_cork_full *cork,
1639 struct inet6_cork *v6_cork)
1640 {
1641 if (v6_cork->opt) {
1642 kfree(v6_cork->opt->dst0opt);
1643 kfree(v6_cork->opt->dst1opt);
1644 kfree(v6_cork->opt->hopopt);
1645 kfree(v6_cork->opt->srcrt);
1646 kfree(v6_cork->opt);
1647 v6_cork->opt = NULL;
1648 }
1649
1650 if (cork->base.dst) {
1651 dst_release(cork->base.dst);
1652 cork->base.dst = NULL;
1653 cork->base.flags &= ~IPCORK_ALLFRAG;
1654 }
1655 memset(&cork->fl, 0, sizeof(cork->fl));
1656 }
1657
1658 struct sk_buff *__ip6_make_skb(struct sock *sk,
1659 struct sk_buff_head *queue,
1660 struct inet_cork_full *cork,
1661 struct inet6_cork *v6_cork)
1662 {
1663 struct sk_buff *skb, *tmp_skb;
1664 struct sk_buff **tail_skb;
1665 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1666 struct ipv6_pinfo *np = inet6_sk(sk);
1667 struct net *net = sock_net(sk);
1668 struct ipv6hdr *hdr;
1669 struct ipv6_txoptions *opt = v6_cork->opt;
1670 struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1671 struct flowi6 *fl6 = &cork->fl.u.ip6;
1672 unsigned char proto = fl6->flowi6_proto;
1673
1674 skb = __skb_dequeue(queue);
1675 if (!skb)
1676 goto out;
1677 tail_skb = &(skb_shinfo(skb)->frag_list);
1678
1679 /* move skb->data to ip header from ext header */
1680 if (skb->data < skb_network_header(skb))
1681 __skb_pull(skb, skb_network_offset(skb));
1682 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1683 __skb_pull(tmp_skb, skb_network_header_len(skb));
1684 *tail_skb = tmp_skb;
1685 tail_skb = &(tmp_skb->next);
1686 skb->len += tmp_skb->len;
1687 skb->data_len += tmp_skb->len;
1688 skb->truesize += tmp_skb->truesize;
1689 tmp_skb->destructor = NULL;
1690 tmp_skb->sk = NULL;
1691 }
1692
1693 /* Allow local fragmentation. */
1694 skb->ignore_df = ip6_sk_ignore_df(sk);
1695
1696 *final_dst = fl6->daddr;
1697 __skb_pull(skb, skb_network_header_len(skb));
1698 if (opt && opt->opt_flen)
1699 ipv6_push_frag_opts(skb, opt, &proto);
1700 if (opt && opt->opt_nflen)
1701 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1702
1703 skb_push(skb, sizeof(struct ipv6hdr));
1704 skb_reset_network_header(skb);
1705 hdr = ipv6_hdr(skb);
1706
1707 ip6_flow_hdr(hdr, v6_cork->tclass,
1708 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1709 np->autoflowlabel, fl6));
1710 hdr->hop_limit = v6_cork->hop_limit;
1711 hdr->nexthdr = proto;
1712 hdr->saddr = fl6->saddr;
1713 hdr->daddr = *final_dst;
1714
1715 skb->priority = sk->sk_priority;
1716 skb->mark = sk->sk_mark;
1717
1718 skb_dst_set(skb, dst_clone(&rt->dst));
1719 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1720 if (proto == IPPROTO_ICMPV6) {
1721 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1722
1723 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1724 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1725 }
1726
1727 ip6_cork_release(cork, v6_cork);
1728 out:
1729 return skb;
1730 }
1731
1732 int ip6_send_skb(struct sk_buff *skb)
1733 {
1734 struct net *net = sock_net(skb->sk);
1735 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1736 int err;
1737
1738 err = ip6_local_out(net, skb->sk, skb);
1739 if (err) {
1740 if (err > 0)
1741 err = net_xmit_errno(err);
1742 if (err)
1743 IP6_INC_STATS(net, rt->rt6i_idev,
1744 IPSTATS_MIB_OUTDISCARDS);
1745 }
1746
1747 return err;
1748 }
1749
1750 int ip6_push_pending_frames(struct sock *sk)
1751 {
1752 struct sk_buff *skb;
1753
1754 skb = ip6_finish_skb(sk);
1755 if (!skb)
1756 return 0;
1757
1758 return ip6_send_skb(skb);
1759 }
1760 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1761
1762 static void __ip6_flush_pending_frames(struct sock *sk,
1763 struct sk_buff_head *queue,
1764 struct inet_cork_full *cork,
1765 struct inet6_cork *v6_cork)
1766 {
1767 struct sk_buff *skb;
1768
1769 while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1770 if (skb_dst(skb))
1771 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1772 IPSTATS_MIB_OUTDISCARDS);
1773 kfree_skb(skb);
1774 }
1775
1776 ip6_cork_release(cork, v6_cork);
1777 }
1778
1779 void ip6_flush_pending_frames(struct sock *sk)
1780 {
1781 __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1782 &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1783 }
1784 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1785
1786 struct sk_buff *ip6_make_skb(struct sock *sk,
1787 int getfrag(void *from, char *to, int offset,
1788 int len, int odd, struct sk_buff *skb),
1789 void *from, int length, int transhdrlen,
1790 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1791 struct rt6_info *rt, unsigned int flags,
1792 const struct sockcm_cookie *sockc)
1793 {
1794 struct inet_cork_full cork;
1795 struct inet6_cork v6_cork;
1796 struct sk_buff_head queue;
1797 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1798 int err;
1799
1800 if (flags & MSG_PROBE)
1801 return NULL;
1802
1803 __skb_queue_head_init(&queue);
1804
1805 cork.base.flags = 0;
1806 cork.base.addr = 0;
1807 cork.base.opt = NULL;
1808 v6_cork.opt = NULL;
1809 err = ip6_setup_cork(sk, &cork, &v6_cork, ipc6, rt, fl6);
1810 if (err)
1811 return ERR_PTR(err);
1812
1813 if (ipc6->dontfrag < 0)
1814 ipc6->dontfrag = inet6_sk(sk)->dontfrag;
1815
1816 err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
1817 &current->task_frag, getfrag, from,
1818 length + exthdrlen, transhdrlen + exthdrlen,
1819 flags, ipc6, sockc);
1820 if (err) {
1821 __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
1822 return ERR_PTR(err);
1823 }
1824
1825 return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
1826 }
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