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1/*
2 * IPv6 output functions
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on linux/net/ipv4/ip_output.c
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Changes:
16 * A.N.Kuznetsov : airthmetics in fragmentation.
17 * extension headers are implemented.
18 * route changes now work.
19 * ip6_forward does not confuse sniffers.
20 * etc.
21 *
22 * H. von Brand : Added missing #include <linux/string.h>
23 * Imran Patel : frag id should be in NBO
24 * Kazunori MIYAZAWA @USAGI
25 * : add ip6_append_data and related functions
26 * for datagram xmit
27 */
28
29#include <linux/errno.h>
30#include <linux/kernel.h>
31#include <linux/string.h>
32#include <linux/socket.h>
33#include <linux/net.h>
34#include <linux/netdevice.h>
35#include <linux/if_arp.h>
36#include <linux/in6.h>
37#include <linux/tcp.h>
38#include <linux/route.h>
39#include <linux/module.h>
40#include <linux/slab.h>
41
42#include <linux/netfilter.h>
43#include <linux/netfilter_ipv6.h>
44
45#include <net/sock.h>
46#include <net/snmp.h>
47
48#include <net/ipv6.h>
49#include <net/ndisc.h>
50#include <net/protocol.h>
51#include <net/ip6_route.h>
52#include <net/addrconf.h>
53#include <net/rawv6.h>
54#include <net/icmp.h>
55#include <net/xfrm.h>
56#include <net/checksum.h>
57#include <linux/mroute6.h>
58
59int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
60
61int __ip6_local_out(struct sk_buff *skb)
62{
63 int len;
64
65 len = skb->len - sizeof(struct ipv6hdr);
66 if (len > IPV6_MAXPLEN)
67 len = 0;
68 ipv6_hdr(skb)->payload_len = htons(len);
69
70 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
71 skb_dst(skb)->dev, dst_output);
72}
73
74int ip6_local_out(struct sk_buff *skb)
75{
76 int err;
77
78 err = __ip6_local_out(skb);
79 if (likely(err == 1))
80 err = dst_output(skb);
81
82 return err;
83}
84EXPORT_SYMBOL_GPL(ip6_local_out);
85
86/* dev_loopback_xmit for use with netfilter. */
87static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
88{
89 skb_reset_mac_header(newskb);
90 __skb_pull(newskb, skb_network_offset(newskb));
91 newskb->pkt_type = PACKET_LOOPBACK;
92 newskb->ip_summed = CHECKSUM_UNNECESSARY;
93 WARN_ON(!skb_dst(newskb));
94
95 netif_rx_ni(newskb);
96 return 0;
97}
98
99static int ip6_finish_output2(struct sk_buff *skb)
100{
101 struct dst_entry *dst = skb_dst(skb);
102 struct net_device *dev = dst->dev;
103 struct neighbour *neigh;
104
105 skb->protocol = htons(ETH_P_IPV6);
106 skb->dev = dev;
107
108 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
109 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
110
111 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&
112 ((mroute6_socket(dev_net(dev), skb) &&
113 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
114 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
115 &ipv6_hdr(skb)->saddr))) {
116 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
117
118 /* Do not check for IFF_ALLMULTI; multicast routing
119 is not supported in any case.
120 */
121 if (newskb)
122 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
123 newskb, NULL, newskb->dev,
124 ip6_dev_loopback_xmit);
125
126 if (ipv6_hdr(skb)->hop_limit == 0) {
127 IP6_INC_STATS(dev_net(dev), idev,
128 IPSTATS_MIB_OUTDISCARDS);
129 kfree_skb(skb);
130 return 0;
131 }
132 }
133
134 IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST,
135 skb->len);
136 }
137
138 rcu_read_lock();
139 neigh = dst_get_neighbour(dst);
140 if (neigh) {
141 int res = neigh_output(neigh, skb);
142
143 rcu_read_unlock();
144 return res;
145 }
146 rcu_read_unlock();
147 IP6_INC_STATS_BH(dev_net(dst->dev),
148 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
149 kfree_skb(skb);
150 return -EINVAL;
151}
152
153static int ip6_finish_output(struct sk_buff *skb)
154{
155 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
156 dst_allfrag(skb_dst(skb)))
157 return ip6_fragment(skb, ip6_finish_output2);
158 else
159 return ip6_finish_output2(skb);
160}
161
162int ip6_output(struct sk_buff *skb)
163{
164 struct net_device *dev = skb_dst(skb)->dev;
165 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
166 if (unlikely(idev->cnf.disable_ipv6)) {
167 IP6_INC_STATS(dev_net(dev), idev,
168 IPSTATS_MIB_OUTDISCARDS);
169 kfree_skb(skb);
170 return 0;
171 }
172
173 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, dev,
174 ip6_finish_output,
175 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
176}
177
178/*
179 * xmit an sk_buff (used by TCP, SCTP and DCCP)
180 */
181
182int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
183 struct ipv6_txoptions *opt)
184{
185 struct net *net = sock_net(sk);
186 struct ipv6_pinfo *np = inet6_sk(sk);
187 struct in6_addr *first_hop = &fl6->daddr;
188 struct dst_entry *dst = skb_dst(skb);
189 struct ipv6hdr *hdr;
190 u8 proto = fl6->flowi6_proto;
191 int seg_len = skb->len;
192 int hlimit = -1;
193 int tclass = 0;
194 u32 mtu;
195
196 if (opt) {
197 unsigned int head_room;
198
199 /* First: exthdrs may take lots of space (~8K for now)
200 MAX_HEADER is not enough.
201 */
202 head_room = opt->opt_nflen + opt->opt_flen;
203 seg_len += head_room;
204 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
205
206 if (skb_headroom(skb) < head_room) {
207 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
208 if (skb2 == NULL) {
209 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
210 IPSTATS_MIB_OUTDISCARDS);
211 kfree_skb(skb);
212 return -ENOBUFS;
213 }
214 kfree_skb(skb);
215 skb = skb2;
216 skb_set_owner_w(skb, sk);
217 }
218 if (opt->opt_flen)
219 ipv6_push_frag_opts(skb, opt, &proto);
220 if (opt->opt_nflen)
221 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
222 }
223
224 skb_push(skb, sizeof(struct ipv6hdr));
225 skb_reset_network_header(skb);
226 hdr = ipv6_hdr(skb);
227
228 /*
229 * Fill in the IPv6 header
230 */
231 if (np) {
232 tclass = np->tclass;
233 hlimit = np->hop_limit;
234 }
235 if (hlimit < 0)
236 hlimit = ip6_dst_hoplimit(dst);
237
238 *(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl6->flowlabel;
239
240 hdr->payload_len = htons(seg_len);
241 hdr->nexthdr = proto;
242 hdr->hop_limit = hlimit;
243
244 ipv6_addr_copy(&hdr->saddr, &fl6->saddr);
245 ipv6_addr_copy(&hdr->daddr, first_hop);
246
247 skb->priority = sk->sk_priority;
248 skb->mark = sk->sk_mark;
249
250 mtu = dst_mtu(dst);
251 if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
252 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
253 IPSTATS_MIB_OUT, skb->len);
254 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
255 dst->dev, dst_output);
256 }
257
258 if (net_ratelimit())
259 printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
260 skb->dev = dst->dev;
261 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
262 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
263 kfree_skb(skb);
264 return -EMSGSIZE;
265}
266
267EXPORT_SYMBOL(ip6_xmit);
268
269/*
270 * To avoid extra problems ND packets are send through this
271 * routine. It's code duplication but I really want to avoid
272 * extra checks since ipv6_build_header is used by TCP (which
273 * is for us performance critical)
274 */
275
276int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
277 const struct in6_addr *saddr, const struct in6_addr *daddr,
278 int proto, int len)
279{
280 struct ipv6_pinfo *np = inet6_sk(sk);
281 struct ipv6hdr *hdr;
282
283 skb->protocol = htons(ETH_P_IPV6);
284 skb->dev = dev;
285
286 skb_reset_network_header(skb);
287 skb_put(skb, sizeof(struct ipv6hdr));
288 hdr = ipv6_hdr(skb);
289
290 *(__be32*)hdr = htonl(0x60000000);
291
292 hdr->payload_len = htons(len);
293 hdr->nexthdr = proto;
294 hdr->hop_limit = np->hop_limit;
295
296 ipv6_addr_copy(&hdr->saddr, saddr);
297 ipv6_addr_copy(&hdr->daddr, daddr);
298
299 return 0;
300}
301
302static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
303{
304 struct ip6_ra_chain *ra;
305 struct sock *last = NULL;
306
307 read_lock(&ip6_ra_lock);
308 for (ra = ip6_ra_chain; ra; ra = ra->next) {
309 struct sock *sk = ra->sk;
310 if (sk && ra->sel == sel &&
311 (!sk->sk_bound_dev_if ||
312 sk->sk_bound_dev_if == skb->dev->ifindex)) {
313 if (last) {
314 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
315 if (skb2)
316 rawv6_rcv(last, skb2);
317 }
318 last = sk;
319 }
320 }
321
322 if (last) {
323 rawv6_rcv(last, skb);
324 read_unlock(&ip6_ra_lock);
325 return 1;
326 }
327 read_unlock(&ip6_ra_lock);
328 return 0;
329}
330
331static int ip6_forward_proxy_check(struct sk_buff *skb)
332{
333 struct ipv6hdr *hdr = ipv6_hdr(skb);
334 u8 nexthdr = hdr->nexthdr;
335 int offset;
336
337 if (ipv6_ext_hdr(nexthdr)) {
338 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
339 if (offset < 0)
340 return 0;
341 } else
342 offset = sizeof(struct ipv6hdr);
343
344 if (nexthdr == IPPROTO_ICMPV6) {
345 struct icmp6hdr *icmp6;
346
347 if (!pskb_may_pull(skb, (skb_network_header(skb) +
348 offset + 1 - skb->data)))
349 return 0;
350
351 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
352
353 switch (icmp6->icmp6_type) {
354 case NDISC_ROUTER_SOLICITATION:
355 case NDISC_ROUTER_ADVERTISEMENT:
356 case NDISC_NEIGHBOUR_SOLICITATION:
357 case NDISC_NEIGHBOUR_ADVERTISEMENT:
358 case NDISC_REDIRECT:
359 /* For reaction involving unicast neighbor discovery
360 * message destined to the proxied address, pass it to
361 * input function.
362 */
363 return 1;
364 default:
365 break;
366 }
367 }
368
369 /*
370 * The proxying router can't forward traffic sent to a link-local
371 * address, so signal the sender and discard the packet. This
372 * behavior is clarified by the MIPv6 specification.
373 */
374 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
375 dst_link_failure(skb);
376 return -1;
377 }
378
379 return 0;
380}
381
382static inline int ip6_forward_finish(struct sk_buff *skb)
383{
384 return dst_output(skb);
385}
386
387int ip6_forward(struct sk_buff *skb)
388{
389 struct dst_entry *dst = skb_dst(skb);
390 struct ipv6hdr *hdr = ipv6_hdr(skb);
391 struct inet6_skb_parm *opt = IP6CB(skb);
392 struct net *net = dev_net(dst->dev);
393 struct neighbour *n;
394 u32 mtu;
395
396 if (net->ipv6.devconf_all->forwarding == 0)
397 goto error;
398
399 if (skb_warn_if_lro(skb))
400 goto drop;
401
402 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
403 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
404 goto drop;
405 }
406
407 if (skb->pkt_type != PACKET_HOST)
408 goto drop;
409
410 skb_forward_csum(skb);
411
412 /*
413 * We DO NOT make any processing on
414 * RA packets, pushing them to user level AS IS
415 * without ane WARRANTY that application will be able
416 * to interpret them. The reason is that we
417 * cannot make anything clever here.
418 *
419 * We are not end-node, so that if packet contains
420 * AH/ESP, we cannot make anything.
421 * Defragmentation also would be mistake, RA packets
422 * cannot be fragmented, because there is no warranty
423 * that different fragments will go along one path. --ANK
424 */
425 if (opt->ra) {
426 u8 *ptr = skb_network_header(skb) + opt->ra;
427 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
428 return 0;
429 }
430
431 /*
432 * check and decrement ttl
433 */
434 if (hdr->hop_limit <= 1) {
435 /* Force OUTPUT device used as source address */
436 skb->dev = dst->dev;
437 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
438 IP6_INC_STATS_BH(net,
439 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
440
441 kfree_skb(skb);
442 return -ETIMEDOUT;
443 }
444
445 /* XXX: idev->cnf.proxy_ndp? */
446 if (net->ipv6.devconf_all->proxy_ndp &&
447 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
448 int proxied = ip6_forward_proxy_check(skb);
449 if (proxied > 0)
450 return ip6_input(skb);
451 else if (proxied < 0) {
452 IP6_INC_STATS(net, ip6_dst_idev(dst),
453 IPSTATS_MIB_INDISCARDS);
454 goto drop;
455 }
456 }
457
458 if (!xfrm6_route_forward(skb)) {
459 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
460 goto drop;
461 }
462 dst = skb_dst(skb);
463
464 /* IPv6 specs say nothing about it, but it is clear that we cannot
465 send redirects to source routed frames.
466 We don't send redirects to frames decapsulated from IPsec.
467 */
468 n = dst_get_neighbour(dst);
469 if (skb->dev == dst->dev && n && opt->srcrt == 0 && !skb_sec_path(skb)) {
470 struct in6_addr *target = NULL;
471 struct rt6_info *rt;
472
473 /*
474 * incoming and outgoing devices are the same
475 * send a redirect.
476 */
477
478 rt = (struct rt6_info *) dst;
479 if ((rt->rt6i_flags & RTF_GATEWAY))
480 target = (struct in6_addr*)&n->primary_key;
481 else
482 target = &hdr->daddr;
483
484 if (!rt->rt6i_peer)
485 rt6_bind_peer(rt, 1);
486
487 /* Limit redirects both by destination (here)
488 and by source (inside ndisc_send_redirect)
489 */
490 if (inet_peer_xrlim_allow(rt->rt6i_peer, 1*HZ))
491 ndisc_send_redirect(skb, n, target);
492 } else {
493 int addrtype = ipv6_addr_type(&hdr->saddr);
494
495 /* This check is security critical. */
496 if (addrtype == IPV6_ADDR_ANY ||
497 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
498 goto error;
499 if (addrtype & IPV6_ADDR_LINKLOCAL) {
500 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
501 ICMPV6_NOT_NEIGHBOUR, 0);
502 goto error;
503 }
504 }
505
506 mtu = dst_mtu(dst);
507 if (mtu < IPV6_MIN_MTU)
508 mtu = IPV6_MIN_MTU;
509
510 if (skb->len > mtu && !skb_is_gso(skb)) {
511 /* Again, force OUTPUT device used as source address */
512 skb->dev = dst->dev;
513 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
514 IP6_INC_STATS_BH(net,
515 ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
516 IP6_INC_STATS_BH(net,
517 ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
518 kfree_skb(skb);
519 return -EMSGSIZE;
520 }
521
522 if (skb_cow(skb, dst->dev->hard_header_len)) {
523 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
524 goto drop;
525 }
526
527 hdr = ipv6_hdr(skb);
528
529 /* Mangling hops number delayed to point after skb COW */
530
531 hdr->hop_limit--;
532
533 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
534 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
535 ip6_forward_finish);
536
537error:
538 IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
539drop:
540 kfree_skb(skb);
541 return -EINVAL;
542}
543
544static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
545{
546 to->pkt_type = from->pkt_type;
547 to->priority = from->priority;
548 to->protocol = from->protocol;
549 skb_dst_drop(to);
550 skb_dst_set(to, dst_clone(skb_dst(from)));
551 to->dev = from->dev;
552 to->mark = from->mark;
553
554#ifdef CONFIG_NET_SCHED
555 to->tc_index = from->tc_index;
556#endif
557 nf_copy(to, from);
558#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
559 defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
560 to->nf_trace = from->nf_trace;
561#endif
562 skb_copy_secmark(to, from);
563}
564
565int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
566{
567 u16 offset = sizeof(struct ipv6hdr);
568 struct ipv6_opt_hdr *exthdr =
569 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
570 unsigned int packet_len = skb->tail - skb->network_header;
571 int found_rhdr = 0;
572 *nexthdr = &ipv6_hdr(skb)->nexthdr;
573
574 while (offset + 1 <= packet_len) {
575
576 switch (**nexthdr) {
577
578 case NEXTHDR_HOP:
579 break;
580 case NEXTHDR_ROUTING:
581 found_rhdr = 1;
582 break;
583 case NEXTHDR_DEST:
584#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
585 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
586 break;
587#endif
588 if (found_rhdr)
589 return offset;
590 break;
591 default :
592 return offset;
593 }
594
595 offset += ipv6_optlen(exthdr);
596 *nexthdr = &exthdr->nexthdr;
597 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
598 offset);
599 }
600
601 return offset;
602}
603
604void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
605{
606 static atomic_t ipv6_fragmentation_id;
607 int old, new;
608
609 if (rt) {
610 struct inet_peer *peer;
611
612 if (!rt->rt6i_peer)
613 rt6_bind_peer(rt, 1);
614 peer = rt->rt6i_peer;
615 if (peer) {
616 fhdr->identification = htonl(inet_getid(peer, 0));
617 return;
618 }
619 }
620 do {
621 old = atomic_read(&ipv6_fragmentation_id);
622 new = old + 1;
623 if (!new)
624 new = 1;
625 } while (atomic_cmpxchg(&ipv6_fragmentation_id, old, new) != old);
626 fhdr->identification = htonl(new);
627}
628
629int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
630{
631 struct sk_buff *frag;
632 struct rt6_info *rt = (struct rt6_info*)skb_dst(skb);
633 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
634 struct ipv6hdr *tmp_hdr;
635 struct frag_hdr *fh;
636 unsigned int mtu, hlen, left, len;
637 __be32 frag_id = 0;
638 int ptr, offset = 0, err=0;
639 u8 *prevhdr, nexthdr = 0;
640 struct net *net = dev_net(skb_dst(skb)->dev);
641
642 hlen = ip6_find_1stfragopt(skb, &prevhdr);
643 nexthdr = *prevhdr;
644
645 mtu = ip6_skb_dst_mtu(skb);
646
647 /* We must not fragment if the socket is set to force MTU discovery
648 * or if the skb it not generated by a local socket.
649 */
650 if (!skb->local_df && skb->len > mtu) {
651 skb->dev = skb_dst(skb)->dev;
652 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
653 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
654 IPSTATS_MIB_FRAGFAILS);
655 kfree_skb(skb);
656 return -EMSGSIZE;
657 }
658
659 if (np && np->frag_size < mtu) {
660 if (np->frag_size)
661 mtu = np->frag_size;
662 }
663 mtu -= hlen + sizeof(struct frag_hdr);
664
665 if (skb_has_frag_list(skb)) {
666 int first_len = skb_pagelen(skb);
667 struct sk_buff *frag2;
668
669 if (first_len - hlen > mtu ||
670 ((first_len - hlen) & 7) ||
671 skb_cloned(skb))
672 goto slow_path;
673
674 skb_walk_frags(skb, frag) {
675 /* Correct geometry. */
676 if (frag->len > mtu ||
677 ((frag->len & 7) && frag->next) ||
678 skb_headroom(frag) < hlen)
679 goto slow_path_clean;
680
681 /* Partially cloned skb? */
682 if (skb_shared(frag))
683 goto slow_path_clean;
684
685 BUG_ON(frag->sk);
686 if (skb->sk) {
687 frag->sk = skb->sk;
688 frag->destructor = sock_wfree;
689 }
690 skb->truesize -= frag->truesize;
691 }
692
693 err = 0;
694 offset = 0;
695 frag = skb_shinfo(skb)->frag_list;
696 skb_frag_list_init(skb);
697 /* BUILD HEADER */
698
699 *prevhdr = NEXTHDR_FRAGMENT;
700 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
701 if (!tmp_hdr) {
702 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
703 IPSTATS_MIB_FRAGFAILS);
704 return -ENOMEM;
705 }
706
707 __skb_pull(skb, hlen);
708 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
709 __skb_push(skb, hlen);
710 skb_reset_network_header(skb);
711 memcpy(skb_network_header(skb), tmp_hdr, hlen);
712
713 ipv6_select_ident(fh, rt);
714 fh->nexthdr = nexthdr;
715 fh->reserved = 0;
716 fh->frag_off = htons(IP6_MF);
717 frag_id = fh->identification;
718
719 first_len = skb_pagelen(skb);
720 skb->data_len = first_len - skb_headlen(skb);
721 skb->len = first_len;
722 ipv6_hdr(skb)->payload_len = htons(first_len -
723 sizeof(struct ipv6hdr));
724
725 dst_hold(&rt->dst);
726
727 for (;;) {
728 /* Prepare header of the next frame,
729 * before previous one went down. */
730 if (frag) {
731 frag->ip_summed = CHECKSUM_NONE;
732 skb_reset_transport_header(frag);
733 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
734 __skb_push(frag, hlen);
735 skb_reset_network_header(frag);
736 memcpy(skb_network_header(frag), tmp_hdr,
737 hlen);
738 offset += skb->len - hlen - sizeof(struct frag_hdr);
739 fh->nexthdr = nexthdr;
740 fh->reserved = 0;
741 fh->frag_off = htons(offset);
742 if (frag->next != NULL)
743 fh->frag_off |= htons(IP6_MF);
744 fh->identification = frag_id;
745 ipv6_hdr(frag)->payload_len =
746 htons(frag->len -
747 sizeof(struct ipv6hdr));
748 ip6_copy_metadata(frag, skb);
749 }
750
751 err = output(skb);
752 if(!err)
753 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
754 IPSTATS_MIB_FRAGCREATES);
755
756 if (err || !frag)
757 break;
758
759 skb = frag;
760 frag = skb->next;
761 skb->next = NULL;
762 }
763
764 kfree(tmp_hdr);
765
766 if (err == 0) {
767 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
768 IPSTATS_MIB_FRAGOKS);
769 dst_release(&rt->dst);
770 return 0;
771 }
772
773 while (frag) {
774 skb = frag->next;
775 kfree_skb(frag);
776 frag = skb;
777 }
778
779 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
780 IPSTATS_MIB_FRAGFAILS);
781 dst_release(&rt->dst);
782 return err;
783
784slow_path_clean:
785 skb_walk_frags(skb, frag2) {
786 if (frag2 == frag)
787 break;
788 frag2->sk = NULL;
789 frag2->destructor = NULL;
790 skb->truesize += frag2->truesize;
791 }
792 }
793
794slow_path:
795 left = skb->len - hlen; /* Space per frame */
796 ptr = hlen; /* Where to start from */
797
798 /*
799 * Fragment the datagram.
800 */
801
802 *prevhdr = NEXTHDR_FRAGMENT;
803
804 /*
805 * Keep copying data until we run out.
806 */
807 while(left > 0) {
808 len = left;
809 /* IF: it doesn't fit, use 'mtu' - the data space left */
810 if (len > mtu)
811 len = mtu;
812 /* IF: we are not sending up to and including the packet end
813 then align the next start on an eight byte boundary */
814 if (len < left) {
815 len &= ~7;
816 }
817 /*
818 * Allocate buffer.
819 */
820
821 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_ALLOCATED_SPACE(rt->dst.dev), GFP_ATOMIC)) == NULL) {
822 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
823 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
824 IPSTATS_MIB_FRAGFAILS);
825 err = -ENOMEM;
826 goto fail;
827 }
828
829 /*
830 * Set up data on packet
831 */
832
833 ip6_copy_metadata(frag, skb);
834 skb_reserve(frag, LL_RESERVED_SPACE(rt->dst.dev));
835 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
836 skb_reset_network_header(frag);
837 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
838 frag->transport_header = (frag->network_header + hlen +
839 sizeof(struct frag_hdr));
840
841 /*
842 * Charge the memory for the fragment to any owner
843 * it might possess
844 */
845 if (skb->sk)
846 skb_set_owner_w(frag, skb->sk);
847
848 /*
849 * Copy the packet header into the new buffer.
850 */
851 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
852
853 /*
854 * Build fragment header.
855 */
856 fh->nexthdr = nexthdr;
857 fh->reserved = 0;
858 if (!frag_id) {
859 ipv6_select_ident(fh, rt);
860 frag_id = fh->identification;
861 } else
862 fh->identification = frag_id;
863
864 /*
865 * Copy a block of the IP datagram.
866 */
867 if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len))
868 BUG();
869 left -= len;
870
871 fh->frag_off = htons(offset);
872 if (left > 0)
873 fh->frag_off |= htons(IP6_MF);
874 ipv6_hdr(frag)->payload_len = htons(frag->len -
875 sizeof(struct ipv6hdr));
876
877 ptr += len;
878 offset += len;
879
880 /*
881 * Put this fragment into the sending queue.
882 */
883 err = output(frag);
884 if (err)
885 goto fail;
886
887 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
888 IPSTATS_MIB_FRAGCREATES);
889 }
890 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
891 IPSTATS_MIB_FRAGOKS);
892 kfree_skb(skb);
893 return err;
894
895fail:
896 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
897 IPSTATS_MIB_FRAGFAILS);
898 kfree_skb(skb);
899 return err;
900}
901
902static inline int ip6_rt_check(const struct rt6key *rt_key,
903 const struct in6_addr *fl_addr,
904 const struct in6_addr *addr_cache)
905{
906 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
907 (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache));
908}
909
910static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
911 struct dst_entry *dst,
912 const struct flowi6 *fl6)
913{
914 struct ipv6_pinfo *np = inet6_sk(sk);
915 struct rt6_info *rt = (struct rt6_info *)dst;
916
917 if (!dst)
918 goto out;
919
920 /* Yes, checking route validity in not connected
921 * case is not very simple. Take into account,
922 * that we do not support routing by source, TOS,
923 * and MSG_DONTROUTE --ANK (980726)
924 *
925 * 1. ip6_rt_check(): If route was host route,
926 * check that cached destination is current.
927 * If it is network route, we still may
928 * check its validity using saved pointer
929 * to the last used address: daddr_cache.
930 * We do not want to save whole address now,
931 * (because main consumer of this service
932 * is tcp, which has not this problem),
933 * so that the last trick works only on connected
934 * sockets.
935 * 2. oif also should be the same.
936 */
937 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
938#ifdef CONFIG_IPV6_SUBTREES
939 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
940#endif
941 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
942 dst_release(dst);
943 dst = NULL;
944 }
945
946out:
947 return dst;
948}
949
950static int ip6_dst_lookup_tail(struct sock *sk,
951 struct dst_entry **dst, struct flowi6 *fl6)
952{
953 struct net *net = sock_net(sk);
954#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
955 struct neighbour *n;
956#endif
957 int err;
958
959 if (*dst == NULL)
960 *dst = ip6_route_output(net, sk, fl6);
961
962 if ((err = (*dst)->error))
963 goto out_err_release;
964
965 if (ipv6_addr_any(&fl6->saddr)) {
966 struct rt6_info *rt = (struct rt6_info *) *dst;
967 err = ip6_route_get_saddr(net, rt, &fl6->daddr,
968 sk ? inet6_sk(sk)->srcprefs : 0,
969 &fl6->saddr);
970 if (err)
971 goto out_err_release;
972 }
973
974#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
975 /*
976 * Here if the dst entry we've looked up
977 * has a neighbour entry that is in the INCOMPLETE
978 * state and the src address from the flow is
979 * marked as OPTIMISTIC, we release the found
980 * dst entry and replace it instead with the
981 * dst entry of the nexthop router
982 */
983 rcu_read_lock();
984 n = dst_get_neighbour(*dst);
985 if (n && !(n->nud_state & NUD_VALID)) {
986 struct inet6_ifaddr *ifp;
987 struct flowi6 fl_gw6;
988 int redirect;
989
990 rcu_read_unlock();
991 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
992 (*dst)->dev, 1);
993
994 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
995 if (ifp)
996 in6_ifa_put(ifp);
997
998 if (redirect) {
999 /*
1000 * We need to get the dst entry for the
1001 * default router instead
1002 */
1003 dst_release(*dst);
1004 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1005 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1006 *dst = ip6_route_output(net, sk, &fl_gw6);
1007 if ((err = (*dst)->error))
1008 goto out_err_release;
1009 }
1010 } else {
1011 rcu_read_unlock();
1012 }
1013#endif
1014
1015 return 0;
1016
1017out_err_release:
1018 if (err == -ENETUNREACH)
1019 IP6_INC_STATS_BH(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1020 dst_release(*dst);
1021 *dst = NULL;
1022 return err;
1023}
1024
1025/**
1026 * ip6_dst_lookup - perform route lookup on flow
1027 * @sk: socket which provides route info
1028 * @dst: pointer to dst_entry * for result
1029 * @fl6: flow to lookup
1030 *
1031 * This function performs a route lookup on the given flow.
1032 *
1033 * It returns zero on success, or a standard errno code on error.
1034 */
1035int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6)
1036{
1037 *dst = NULL;
1038 return ip6_dst_lookup_tail(sk, dst, fl6);
1039}
1040EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1041
1042/**
1043 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1044 * @sk: socket which provides route info
1045 * @fl6: flow to lookup
1046 * @final_dst: final destination address for ipsec lookup
1047 * @can_sleep: we are in a sleepable context
1048 *
1049 * This function performs a route lookup on the given flow.
1050 *
1051 * It returns a valid dst pointer on success, or a pointer encoded
1052 * error code.
1053 */
1054struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1055 const struct in6_addr *final_dst,
1056 bool can_sleep)
1057{
1058 struct dst_entry *dst = NULL;
1059 int err;
1060
1061 err = ip6_dst_lookup_tail(sk, &dst, fl6);
1062 if (err)
1063 return ERR_PTR(err);
1064 if (final_dst)
1065 ipv6_addr_copy(&fl6->daddr, final_dst);
1066 if (can_sleep)
1067 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
1068
1069 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1070}
1071EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1072
1073/**
1074 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1075 * @sk: socket which provides the dst cache and route info
1076 * @fl6: flow to lookup
1077 * @final_dst: final destination address for ipsec lookup
1078 * @can_sleep: we are in a sleepable context
1079 *
1080 * This function performs a route lookup on the given flow with the
1081 * possibility of using the cached route in the socket if it is valid.
1082 * It will take the socket dst lock when operating on the dst cache.
1083 * As a result, this function can only be used in process context.
1084 *
1085 * It returns a valid dst pointer on success, or a pointer encoded
1086 * error code.
1087 */
1088struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1089 const struct in6_addr *final_dst,
1090 bool can_sleep)
1091{
1092 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1093 int err;
1094
1095 dst = ip6_sk_dst_check(sk, dst, fl6);
1096
1097 err = ip6_dst_lookup_tail(sk, &dst, fl6);
1098 if (err)
1099 return ERR_PTR(err);
1100 if (final_dst)
1101 ipv6_addr_copy(&fl6->daddr, final_dst);
1102 if (can_sleep)
1103 fl6->flowi6_flags |= FLOWI_FLAG_CAN_SLEEP;
1104
1105 return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1106}
1107EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1108
1109static inline int ip6_ufo_append_data(struct sock *sk,
1110 int getfrag(void *from, char *to, int offset, int len,
1111 int odd, struct sk_buff *skb),
1112 void *from, int length, int hh_len, int fragheaderlen,
1113 int transhdrlen, int mtu,unsigned int flags,
1114 struct rt6_info *rt)
1115
1116{
1117 struct sk_buff *skb;
1118 int err;
1119
1120 /* There is support for UDP large send offload by network
1121 * device, so create one single skb packet containing complete
1122 * udp datagram
1123 */
1124 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
1125 skb = sock_alloc_send_skb(sk,
1126 hh_len + fragheaderlen + transhdrlen + 20,
1127 (flags & MSG_DONTWAIT), &err);
1128 if (skb == NULL)
1129 return -ENOMEM;
1130
1131 /* reserve space for Hardware header */
1132 skb_reserve(skb, hh_len);
1133
1134 /* create space for UDP/IP header */
1135 skb_put(skb,fragheaderlen + transhdrlen);
1136
1137 /* initialize network header pointer */
1138 skb_reset_network_header(skb);
1139
1140 /* initialize protocol header pointer */
1141 skb->transport_header = skb->network_header + fragheaderlen;
1142
1143 skb->ip_summed = CHECKSUM_PARTIAL;
1144 skb->csum = 0;
1145 }
1146
1147 err = skb_append_datato_frags(sk,skb, getfrag, from,
1148 (length - transhdrlen));
1149 if (!err) {
1150 struct frag_hdr fhdr;
1151
1152 /* Specify the length of each IPv6 datagram fragment.
1153 * It has to be a multiple of 8.
1154 */
1155 skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
1156 sizeof(struct frag_hdr)) & ~7;
1157 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1158 ipv6_select_ident(&fhdr, rt);
1159 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
1160 __skb_queue_tail(&sk->sk_write_queue, skb);
1161
1162 return 0;
1163 }
1164 /* There is not enough support do UPD LSO,
1165 * so follow normal path
1166 */
1167 kfree_skb(skb);
1168
1169 return err;
1170}
1171
1172static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1173 gfp_t gfp)
1174{
1175 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1176}
1177
1178static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1179 gfp_t gfp)
1180{
1181 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1182}
1183
1184int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
1185 int offset, int len, int odd, struct sk_buff *skb),
1186 void *from, int length, int transhdrlen,
1187 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi6 *fl6,
1188 struct rt6_info *rt, unsigned int flags, int dontfrag)
1189{
1190 struct inet_sock *inet = inet_sk(sk);
1191 struct ipv6_pinfo *np = inet6_sk(sk);
1192 struct inet_cork *cork;
1193 struct sk_buff *skb;
1194 unsigned int maxfraglen, fragheaderlen;
1195 int exthdrlen;
1196 int hh_len;
1197 int mtu;
1198 int copy;
1199 int err;
1200 int offset = 0;
1201 int csummode = CHECKSUM_NONE;
1202 __u8 tx_flags = 0;
1203
1204 if (flags&MSG_PROBE)
1205 return 0;
1206 cork = &inet->cork.base;
1207 if (skb_queue_empty(&sk->sk_write_queue)) {
1208 /*
1209 * setup for corking
1210 */
1211 if (opt) {
1212 if (WARN_ON(np->cork.opt))
1213 return -EINVAL;
1214
1215 np->cork.opt = kmalloc(opt->tot_len, sk->sk_allocation);
1216 if (unlikely(np->cork.opt == NULL))
1217 return -ENOBUFS;
1218
1219 np->cork.opt->tot_len = opt->tot_len;
1220 np->cork.opt->opt_flen = opt->opt_flen;
1221 np->cork.opt->opt_nflen = opt->opt_nflen;
1222
1223 np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1224 sk->sk_allocation);
1225 if (opt->dst0opt && !np->cork.opt->dst0opt)
1226 return -ENOBUFS;
1227
1228 np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1229 sk->sk_allocation);
1230 if (opt->dst1opt && !np->cork.opt->dst1opt)
1231 return -ENOBUFS;
1232
1233 np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
1234 sk->sk_allocation);
1235 if (opt->hopopt && !np->cork.opt->hopopt)
1236 return -ENOBUFS;
1237
1238 np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1239 sk->sk_allocation);
1240 if (opt->srcrt && !np->cork.opt->srcrt)
1241 return -ENOBUFS;
1242
1243 /* need source address above miyazawa*/
1244 }
1245 dst_hold(&rt->dst);
1246 cork->dst = &rt->dst;
1247 inet->cork.fl.u.ip6 = *fl6;
1248 np->cork.hop_limit = hlimit;
1249 np->cork.tclass = tclass;
1250 mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
1251 rt->dst.dev->mtu : dst_mtu(rt->dst.path);
1252 if (np->frag_size < mtu) {
1253 if (np->frag_size)
1254 mtu = np->frag_size;
1255 }
1256 cork->fragsize = mtu;
1257 if (dst_allfrag(rt->dst.path))
1258 cork->flags |= IPCORK_ALLFRAG;
1259 cork->length = 0;
1260 sk->sk_sndmsg_page = NULL;
1261 sk->sk_sndmsg_off = 0;
1262 exthdrlen = rt->dst.header_len + (opt ? opt->opt_flen : 0) -
1263 rt->rt6i_nfheader_len;
1264 length += exthdrlen;
1265 transhdrlen += exthdrlen;
1266 } else {
1267 rt = (struct rt6_info *)cork->dst;
1268 fl6 = &inet->cork.fl.u.ip6;
1269 opt = np->cork.opt;
1270 transhdrlen = 0;
1271 exthdrlen = 0;
1272 mtu = cork->fragsize;
1273 }
1274
1275 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1276
1277 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1278 (opt ? opt->opt_nflen : 0);
1279 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
1280
1281 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
1282 if (cork->length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
1283 ipv6_local_error(sk, EMSGSIZE, fl6, mtu-exthdrlen);
1284 return -EMSGSIZE;
1285 }
1286 }
1287
1288 /* For UDP, check if TX timestamp is enabled */
1289 if (sk->sk_type == SOCK_DGRAM) {
1290 err = sock_tx_timestamp(sk, &tx_flags);
1291 if (err)
1292 goto error;
1293 }
1294
1295 /*
1296 * Let's try using as much space as possible.
1297 * Use MTU if total length of the message fits into the MTU.
1298 * Otherwise, we need to reserve fragment header and
1299 * fragment alignment (= 8-15 octects, in total).
1300 *
1301 * Note that we may need to "move" the data from the tail of
1302 * of the buffer to the new fragment when we split
1303 * the message.
1304 *
1305 * FIXME: It may be fragmented into multiple chunks
1306 * at once if non-fragmentable extension headers
1307 * are too large.
1308 * --yoshfuji
1309 */
1310
1311 cork->length += length;
1312 if (length > mtu) {
1313 int proto = sk->sk_protocol;
1314 if (dontfrag && (proto == IPPROTO_UDP || proto == IPPROTO_RAW)){
1315 ipv6_local_rxpmtu(sk, fl6, mtu-exthdrlen);
1316 return -EMSGSIZE;
1317 }
1318
1319 if (proto == IPPROTO_UDP &&
1320 (rt->dst.dev->features & NETIF_F_UFO)) {
1321
1322 err = ip6_ufo_append_data(sk, getfrag, from, length,
1323 hh_len, fragheaderlen,
1324 transhdrlen, mtu, flags, rt);
1325 if (err)
1326 goto error;
1327 return 0;
1328 }
1329 }
1330
1331 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
1332 goto alloc_new_skb;
1333
1334 while (length > 0) {
1335 /* Check if the remaining data fits into current packet. */
1336 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1337 if (copy < length)
1338 copy = maxfraglen - skb->len;
1339
1340 if (copy <= 0) {
1341 char *data;
1342 unsigned int datalen;
1343 unsigned int fraglen;
1344 unsigned int fraggap;
1345 unsigned int alloclen;
1346 struct sk_buff *skb_prev;
1347alloc_new_skb:
1348 skb_prev = skb;
1349
1350 /* There's no room in the current skb */
1351 if (skb_prev)
1352 fraggap = skb_prev->len - maxfraglen;
1353 else
1354 fraggap = 0;
1355
1356 /*
1357 * If remaining data exceeds the mtu,
1358 * we know we need more fragment(s).
1359 */
1360 datalen = length + fraggap;
1361 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1362 datalen = maxfraglen - fragheaderlen;
1363
1364 fraglen = datalen + fragheaderlen;
1365 if ((flags & MSG_MORE) &&
1366 !(rt->dst.dev->features&NETIF_F_SG))
1367 alloclen = mtu;
1368 else
1369 alloclen = datalen + fragheaderlen;
1370
1371 /*
1372 * The last fragment gets additional space at tail.
1373 * Note: we overallocate on fragments with MSG_MODE
1374 * because we have no idea if we're the last one.
1375 */
1376 if (datalen == length + fraggap)
1377 alloclen += rt->dst.trailer_len;
1378
1379 /*
1380 * We just reserve space for fragment header.
1381 * Note: this may be overallocation if the message
1382 * (without MSG_MORE) fits into the MTU.
1383 */
1384 alloclen += sizeof(struct frag_hdr);
1385
1386 if (transhdrlen) {
1387 skb = sock_alloc_send_skb(sk,
1388 alloclen + hh_len,
1389 (flags & MSG_DONTWAIT), &err);
1390 } else {
1391 skb = NULL;
1392 if (atomic_read(&sk->sk_wmem_alloc) <=
1393 2 * sk->sk_sndbuf)
1394 skb = sock_wmalloc(sk,
1395 alloclen + hh_len, 1,
1396 sk->sk_allocation);
1397 if (unlikely(skb == NULL))
1398 err = -ENOBUFS;
1399 else {
1400 /* Only the initial fragment
1401 * is time stamped.
1402 */
1403 tx_flags = 0;
1404 }
1405 }
1406 if (skb == NULL)
1407 goto error;
1408 /*
1409 * Fill in the control structures
1410 */
1411 skb->ip_summed = csummode;
1412 skb->csum = 0;
1413 /* reserve for fragmentation */
1414 skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
1415
1416 if (sk->sk_type == SOCK_DGRAM)
1417 skb_shinfo(skb)->tx_flags = tx_flags;
1418
1419 /*
1420 * Find where to start putting bytes
1421 */
1422 data = skb_put(skb, fraglen);
1423 skb_set_network_header(skb, exthdrlen);
1424 data += fragheaderlen;
1425 skb->transport_header = (skb->network_header +
1426 fragheaderlen);
1427 if (fraggap) {
1428 skb->csum = skb_copy_and_csum_bits(
1429 skb_prev, maxfraglen,
1430 data + transhdrlen, fraggap, 0);
1431 skb_prev->csum = csum_sub(skb_prev->csum,
1432 skb->csum);
1433 data += fraggap;
1434 pskb_trim_unique(skb_prev, maxfraglen);
1435 }
1436 copy = datalen - transhdrlen - fraggap;
1437 if (copy < 0) {
1438 err = -EINVAL;
1439 kfree_skb(skb);
1440 goto error;
1441 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1442 err = -EFAULT;
1443 kfree_skb(skb);
1444 goto error;
1445 }
1446
1447 offset += copy;
1448 length -= datalen - fraggap;
1449 transhdrlen = 0;
1450 exthdrlen = 0;
1451 csummode = CHECKSUM_NONE;
1452
1453 /*
1454 * Put the packet on the pending queue
1455 */
1456 __skb_queue_tail(&sk->sk_write_queue, skb);
1457 continue;
1458 }
1459
1460 if (copy > length)
1461 copy = length;
1462
1463 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1464 unsigned int off;
1465
1466 off = skb->len;
1467 if (getfrag(from, skb_put(skb, copy),
1468 offset, copy, off, skb) < 0) {
1469 __skb_trim(skb, off);
1470 err = -EFAULT;
1471 goto error;
1472 }
1473 } else {
1474 int i = skb_shinfo(skb)->nr_frags;
1475 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1476 struct page *page = sk->sk_sndmsg_page;
1477 int off = sk->sk_sndmsg_off;
1478 unsigned int left;
1479
1480 if (page && (left = PAGE_SIZE - off) > 0) {
1481 if (copy >= left)
1482 copy = left;
1483 if (page != frag->page) {
1484 if (i == MAX_SKB_FRAGS) {
1485 err = -EMSGSIZE;
1486 goto error;
1487 }
1488 get_page(page);
1489 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1490 frag = &skb_shinfo(skb)->frags[i];
1491 }
1492 } else if(i < MAX_SKB_FRAGS) {
1493 if (copy > PAGE_SIZE)
1494 copy = PAGE_SIZE;
1495 page = alloc_pages(sk->sk_allocation, 0);
1496 if (page == NULL) {
1497 err = -ENOMEM;
1498 goto error;
1499 }
1500 sk->sk_sndmsg_page = page;
1501 sk->sk_sndmsg_off = 0;
1502
1503 skb_fill_page_desc(skb, i, page, 0, 0);
1504 frag = &skb_shinfo(skb)->frags[i];
1505 } else {
1506 err = -EMSGSIZE;
1507 goto error;
1508 }
1509 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1510 err = -EFAULT;
1511 goto error;
1512 }
1513 sk->sk_sndmsg_off += copy;
1514 frag->size += copy;
1515 skb->len += copy;
1516 skb->data_len += copy;
1517 skb->truesize += copy;
1518 atomic_add(copy, &sk->sk_wmem_alloc);
1519 }
1520 offset += copy;
1521 length -= copy;
1522 }
1523 return 0;
1524error:
1525 cork->length -= length;
1526 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1527 return err;
1528}
1529
1530static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
1531{
1532 if (np->cork.opt) {
1533 kfree(np->cork.opt->dst0opt);
1534 kfree(np->cork.opt->dst1opt);
1535 kfree(np->cork.opt->hopopt);
1536 kfree(np->cork.opt->srcrt);
1537 kfree(np->cork.opt);
1538 np->cork.opt = NULL;
1539 }
1540
1541 if (inet->cork.base.dst) {
1542 dst_release(inet->cork.base.dst);
1543 inet->cork.base.dst = NULL;
1544 inet->cork.base.flags &= ~IPCORK_ALLFRAG;
1545 }
1546 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1547}
1548
1549int ip6_push_pending_frames(struct sock *sk)
1550{
1551 struct sk_buff *skb, *tmp_skb;
1552 struct sk_buff **tail_skb;
1553 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1554 struct inet_sock *inet = inet_sk(sk);
1555 struct ipv6_pinfo *np = inet6_sk(sk);
1556 struct net *net = sock_net(sk);
1557 struct ipv6hdr *hdr;
1558 struct ipv6_txoptions *opt = np->cork.opt;
1559 struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
1560 struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
1561 unsigned char proto = fl6->flowi6_proto;
1562 int err = 0;
1563
1564 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1565 goto out;
1566 tail_skb = &(skb_shinfo(skb)->frag_list);
1567
1568 /* move skb->data to ip header from ext header */
1569 if (skb->data < skb_network_header(skb))
1570 __skb_pull(skb, skb_network_offset(skb));
1571 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1572 __skb_pull(tmp_skb, skb_network_header_len(skb));
1573 *tail_skb = tmp_skb;
1574 tail_skb = &(tmp_skb->next);
1575 skb->len += tmp_skb->len;
1576 skb->data_len += tmp_skb->len;
1577 skb->truesize += tmp_skb->truesize;
1578 tmp_skb->destructor = NULL;
1579 tmp_skb->sk = NULL;
1580 }
1581
1582 /* Allow local fragmentation. */
1583 if (np->pmtudisc < IPV6_PMTUDISC_DO)
1584 skb->local_df = 1;
1585
1586 ipv6_addr_copy(final_dst, &fl6->daddr);
1587 __skb_pull(skb, skb_network_header_len(skb));
1588 if (opt && opt->opt_flen)
1589 ipv6_push_frag_opts(skb, opt, &proto);
1590 if (opt && opt->opt_nflen)
1591 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1592
1593 skb_push(skb, sizeof(struct ipv6hdr));
1594 skb_reset_network_header(skb);
1595 hdr = ipv6_hdr(skb);
1596
1597 *(__be32*)hdr = fl6->flowlabel |
1598 htonl(0x60000000 | ((int)np->cork.tclass << 20));
1599
1600 hdr->hop_limit = np->cork.hop_limit;
1601 hdr->nexthdr = proto;
1602 ipv6_addr_copy(&hdr->saddr, &fl6->saddr);
1603 ipv6_addr_copy(&hdr->daddr, final_dst);
1604
1605 skb->priority = sk->sk_priority;
1606 skb->mark = sk->sk_mark;
1607
1608 skb_dst_set(skb, dst_clone(&rt->dst));
1609 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1610 if (proto == IPPROTO_ICMPV6) {
1611 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1612
1613 ICMP6MSGOUT_INC_STATS_BH(net, idev, icmp6_hdr(skb)->icmp6_type);
1614 ICMP6_INC_STATS_BH(net, idev, ICMP6_MIB_OUTMSGS);
1615 }
1616
1617 err = ip6_local_out(skb);
1618 if (err) {
1619 if (err > 0)
1620 err = net_xmit_errno(err);
1621 if (err)
1622 goto error;
1623 }
1624
1625out:
1626 ip6_cork_release(inet, np);
1627 return err;
1628error:
1629 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1630 goto out;
1631}
1632
1633void ip6_flush_pending_frames(struct sock *sk)
1634{
1635 struct sk_buff *skb;
1636
1637 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1638 if (skb_dst(skb))
1639 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1640 IPSTATS_MIB_OUTDISCARDS);
1641 kfree_skb(skb);
1642 }
1643
1644 ip6_cork_release(inet_sk(sk), inet6_sk(sk));
1645}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IPv6 output functions
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on linux/net/ipv4/ip_output.c
10 *
11 * Changes:
12 * A.N.Kuznetsov : airthmetics in fragmentation.
13 * extension headers are implemented.
14 * route changes now work.
15 * ip6_forward does not confuse sniffers.
16 * etc.
17 *
18 * H. von Brand : Added missing #include <linux/string.h>
19 * Imran Patel : frag id should be in NBO
20 * Kazunori MIYAZAWA @USAGI
21 * : add ip6_append_data and related functions
22 * for datagram xmit
23 */
24
25#include <linux/errno.h>
26#include <linux/kernel.h>
27#include <linux/string.h>
28#include <linux/socket.h>
29#include <linux/net.h>
30#include <linux/netdevice.h>
31#include <linux/if_arp.h>
32#include <linux/in6.h>
33#include <linux/tcp.h>
34#include <linux/route.h>
35#include <linux/module.h>
36#include <linux/slab.h>
37
38#include <linux/bpf-cgroup.h>
39#include <linux/netfilter.h>
40#include <linux/netfilter_ipv6.h>
41
42#include <net/sock.h>
43#include <net/snmp.h>
44
45#include <net/gso.h>
46#include <net/ipv6.h>
47#include <net/ndisc.h>
48#include <net/protocol.h>
49#include <net/ip6_route.h>
50#include <net/addrconf.h>
51#include <net/rawv6.h>
52#include <net/icmp.h>
53#include <net/xfrm.h>
54#include <net/checksum.h>
55#include <linux/mroute6.h>
56#include <net/l3mdev.h>
57#include <net/lwtunnel.h>
58#include <net/ip_tunnels.h>
59
60static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
61{
62 struct dst_entry *dst = skb_dst(skb);
63 struct net_device *dev = dst->dev;
64 struct inet6_dev *idev = ip6_dst_idev(dst);
65 unsigned int hh_len = LL_RESERVED_SPACE(dev);
66 const struct in6_addr *daddr, *nexthop;
67 struct ipv6hdr *hdr;
68 struct neighbour *neigh;
69 int ret;
70
71 /* Be paranoid, rather than too clever. */
72 if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) {
73 /* Make sure idev stays alive */
74 rcu_read_lock();
75 skb = skb_expand_head(skb, hh_len);
76 if (!skb) {
77 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
78 rcu_read_unlock();
79 return -ENOMEM;
80 }
81 rcu_read_unlock();
82 }
83
84 hdr = ipv6_hdr(skb);
85 daddr = &hdr->daddr;
86 if (ipv6_addr_is_multicast(daddr)) {
87 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
88 ((mroute6_is_socket(net, skb) &&
89 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
90 ipv6_chk_mcast_addr(dev, daddr, &hdr->saddr))) {
91 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
92
93 /* Do not check for IFF_ALLMULTI; multicast routing
94 is not supported in any case.
95 */
96 if (newskb)
97 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
98 net, sk, newskb, NULL, newskb->dev,
99 dev_loopback_xmit);
100
101 if (hdr->hop_limit == 0) {
102 IP6_INC_STATS(net, idev,
103 IPSTATS_MIB_OUTDISCARDS);
104 kfree_skb(skb);
105 return 0;
106 }
107 }
108
109 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
110 if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL &&
111 !(dev->flags & IFF_LOOPBACK)) {
112 kfree_skb(skb);
113 return 0;
114 }
115 }
116
117 if (lwtunnel_xmit_redirect(dst->lwtstate)) {
118 int res = lwtunnel_xmit(skb);
119
120 if (res != LWTUNNEL_XMIT_CONTINUE)
121 return res;
122 }
123
124 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
125
126 rcu_read_lock();
127 nexthop = rt6_nexthop(dst_rt6_info(dst), daddr);
128 neigh = __ipv6_neigh_lookup_noref(dev, nexthop);
129
130 if (IS_ERR_OR_NULL(neigh)) {
131 if (unlikely(!neigh))
132 neigh = __neigh_create(&nd_tbl, nexthop, dev, false);
133 if (IS_ERR(neigh)) {
134 rcu_read_unlock();
135 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
136 kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
137 return -EINVAL;
138 }
139 }
140 sock_confirm_neigh(skb, neigh);
141 ret = neigh_output(neigh, skb, false);
142 rcu_read_unlock();
143 return ret;
144}
145
146static int
147ip6_finish_output_gso_slowpath_drop(struct net *net, struct sock *sk,
148 struct sk_buff *skb, unsigned int mtu)
149{
150 struct sk_buff *segs, *nskb;
151 netdev_features_t features;
152 int ret = 0;
153
154 /* Please see corresponding comment in ip_finish_output_gso
155 * describing the cases where GSO segment length exceeds the
156 * egress MTU.
157 */
158 features = netif_skb_features(skb);
159 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
160 if (IS_ERR_OR_NULL(segs)) {
161 kfree_skb(skb);
162 return -ENOMEM;
163 }
164
165 consume_skb(skb);
166
167 skb_list_walk_safe(segs, segs, nskb) {
168 int err;
169
170 skb_mark_not_on_list(segs);
171 /* Last GSO segment can be smaller than gso_size (and MTU).
172 * Adding a fragment header would produce an "atomic fragment",
173 * which is considered harmful (RFC-8021). Avoid that.
174 */
175 err = segs->len > mtu ?
176 ip6_fragment(net, sk, segs, ip6_finish_output2) :
177 ip6_finish_output2(net, sk, segs);
178 if (err && ret == 0)
179 ret = err;
180 }
181
182 return ret;
183}
184
185static int ip6_finish_output_gso(struct net *net, struct sock *sk,
186 struct sk_buff *skb, unsigned int mtu)
187{
188 if (!(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
189 !skb_gso_validate_network_len(skb, mtu))
190 return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
191
192 return ip6_finish_output2(net, sk, skb);
193}
194
195static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
196{
197 unsigned int mtu;
198
199#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
200 /* Policy lookup after SNAT yielded a new policy */
201 if (skb_dst(skb)->xfrm) {
202 IP6CB(skb)->flags |= IP6SKB_REROUTED;
203 return dst_output(net, sk, skb);
204 }
205#endif
206
207 mtu = ip6_skb_dst_mtu(skb);
208 if (skb_is_gso(skb))
209 return ip6_finish_output_gso(net, sk, skb, mtu);
210
211 if (skb->len > mtu ||
212 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
213 return ip6_fragment(net, sk, skb, ip6_finish_output2);
214
215 return ip6_finish_output2(net, sk, skb);
216}
217
218static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
219{
220 int ret;
221
222 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
223 switch (ret) {
224 case NET_XMIT_SUCCESS:
225 case NET_XMIT_CN:
226 return __ip6_finish_output(net, sk, skb) ? : ret;
227 default:
228 kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
229 return ret;
230 }
231}
232
233int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
234{
235 struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
236 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
237
238 skb->protocol = htons(ETH_P_IPV6);
239 skb->dev = dev;
240
241 if (unlikely(!idev || READ_ONCE(idev->cnf.disable_ipv6))) {
242 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
243 kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
244 return 0;
245 }
246
247 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
248 net, sk, skb, indev, dev,
249 ip6_finish_output,
250 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
251}
252EXPORT_SYMBOL(ip6_output);
253
254bool ip6_autoflowlabel(struct net *net, const struct sock *sk)
255{
256 if (!inet6_test_bit(AUTOFLOWLABEL_SET, sk))
257 return ip6_default_np_autolabel(net);
258 return inet6_test_bit(AUTOFLOWLABEL, sk);
259}
260
261/*
262 * xmit an sk_buff (used by TCP, SCTP and DCCP)
263 * Note : socket lock is not held for SYNACK packets, but might be modified
264 * by calls to skb_set_owner_w() and ipv6_local_error(),
265 * which are using proper atomic operations or spinlocks.
266 */
267int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
268 __u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority)
269{
270 struct net *net = sock_net(sk);
271 const struct ipv6_pinfo *np = inet6_sk(sk);
272 struct in6_addr *first_hop = &fl6->daddr;
273 struct dst_entry *dst = skb_dst(skb);
274 struct net_device *dev = dst->dev;
275 struct inet6_dev *idev = ip6_dst_idev(dst);
276 struct hop_jumbo_hdr *hop_jumbo;
277 int hoplen = sizeof(*hop_jumbo);
278 unsigned int head_room;
279 struct ipv6hdr *hdr;
280 u8 proto = fl6->flowi6_proto;
281 int seg_len = skb->len;
282 int hlimit = -1;
283 u32 mtu;
284
285 head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
286 if (opt)
287 head_room += opt->opt_nflen + opt->opt_flen;
288
289 if (unlikely(head_room > skb_headroom(skb))) {
290 /* Make sure idev stays alive */
291 rcu_read_lock();
292 skb = skb_expand_head(skb, head_room);
293 if (!skb) {
294 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
295 rcu_read_unlock();
296 return -ENOBUFS;
297 }
298 rcu_read_unlock();
299 }
300
301 if (opt) {
302 seg_len += opt->opt_nflen + opt->opt_flen;
303
304 if (opt->opt_flen)
305 ipv6_push_frag_opts(skb, opt, &proto);
306
307 if (opt->opt_nflen)
308 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,
309 &fl6->saddr);
310 }
311
312 if (unlikely(seg_len > IPV6_MAXPLEN)) {
313 hop_jumbo = skb_push(skb, hoplen);
314
315 hop_jumbo->nexthdr = proto;
316 hop_jumbo->hdrlen = 0;
317 hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
318 hop_jumbo->tlv_len = 4;
319 hop_jumbo->jumbo_payload_len = htonl(seg_len + hoplen);
320
321 proto = IPPROTO_HOPOPTS;
322 seg_len = 0;
323 IP6CB(skb)->flags |= IP6SKB_FAKEJUMBO;
324 }
325
326 skb_push(skb, sizeof(struct ipv6hdr));
327 skb_reset_network_header(skb);
328 hdr = ipv6_hdr(skb);
329
330 /*
331 * Fill in the IPv6 header
332 */
333 if (np)
334 hlimit = READ_ONCE(np->hop_limit);
335 if (hlimit < 0)
336 hlimit = ip6_dst_hoplimit(dst);
337
338 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
339 ip6_autoflowlabel(net, sk), fl6));
340
341 hdr->payload_len = htons(seg_len);
342 hdr->nexthdr = proto;
343 hdr->hop_limit = hlimit;
344
345 hdr->saddr = fl6->saddr;
346 hdr->daddr = *first_hop;
347
348 skb->protocol = htons(ETH_P_IPV6);
349 skb->priority = priority;
350 skb->mark = mark;
351
352 mtu = dst_mtu(dst);
353 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
354 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
355
356 /* if egress device is enslaved to an L3 master device pass the
357 * skb to its handler for processing
358 */
359 skb = l3mdev_ip6_out((struct sock *)sk, skb);
360 if (unlikely(!skb))
361 return 0;
362
363 /* hooks should never assume socket lock is held.
364 * we promote our socket to non const
365 */
366 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
367 net, (struct sock *)sk, skb, NULL, dev,
368 dst_output);
369 }
370
371 skb->dev = dev;
372 /* ipv6_local_error() does not require socket lock,
373 * we promote our socket to non const
374 */
375 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
376
377 IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
378 kfree_skb(skb);
379 return -EMSGSIZE;
380}
381EXPORT_SYMBOL(ip6_xmit);
382
383static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
384{
385 struct ip6_ra_chain *ra;
386 struct sock *last = NULL;
387
388 read_lock(&ip6_ra_lock);
389 for (ra = ip6_ra_chain; ra; ra = ra->next) {
390 struct sock *sk = ra->sk;
391 if (sk && ra->sel == sel &&
392 (!sk->sk_bound_dev_if ||
393 sk->sk_bound_dev_if == skb->dev->ifindex)) {
394
395 if (inet6_test_bit(RTALERT_ISOLATE, sk) &&
396 !net_eq(sock_net(sk), dev_net(skb->dev))) {
397 continue;
398 }
399 if (last) {
400 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
401 if (skb2)
402 rawv6_rcv(last, skb2);
403 }
404 last = sk;
405 }
406 }
407
408 if (last) {
409 rawv6_rcv(last, skb);
410 read_unlock(&ip6_ra_lock);
411 return 1;
412 }
413 read_unlock(&ip6_ra_lock);
414 return 0;
415}
416
417static int ip6_forward_proxy_check(struct sk_buff *skb)
418{
419 struct ipv6hdr *hdr = ipv6_hdr(skb);
420 u8 nexthdr = hdr->nexthdr;
421 __be16 frag_off;
422 int offset;
423
424 if (ipv6_ext_hdr(nexthdr)) {
425 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
426 if (offset < 0)
427 return 0;
428 } else
429 offset = sizeof(struct ipv6hdr);
430
431 if (nexthdr == IPPROTO_ICMPV6) {
432 struct icmp6hdr *icmp6;
433
434 if (!pskb_may_pull(skb, (skb_network_header(skb) +
435 offset + 1 - skb->data)))
436 return 0;
437
438 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
439
440 switch (icmp6->icmp6_type) {
441 case NDISC_ROUTER_SOLICITATION:
442 case NDISC_ROUTER_ADVERTISEMENT:
443 case NDISC_NEIGHBOUR_SOLICITATION:
444 case NDISC_NEIGHBOUR_ADVERTISEMENT:
445 case NDISC_REDIRECT:
446 /* For reaction involving unicast neighbor discovery
447 * message destined to the proxied address, pass it to
448 * input function.
449 */
450 return 1;
451 default:
452 break;
453 }
454 }
455
456 /*
457 * The proxying router can't forward traffic sent to a link-local
458 * address, so signal the sender and discard the packet. This
459 * behavior is clarified by the MIPv6 specification.
460 */
461 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
462 dst_link_failure(skb);
463 return -1;
464 }
465
466 return 0;
467}
468
469static inline int ip6_forward_finish(struct net *net, struct sock *sk,
470 struct sk_buff *skb)
471{
472#ifdef CONFIG_NET_SWITCHDEV
473 if (skb->offload_l3_fwd_mark) {
474 consume_skb(skb);
475 return 0;
476 }
477#endif
478
479 skb_clear_tstamp(skb);
480 return dst_output(net, sk, skb);
481}
482
483static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
484{
485 if (skb->len <= mtu)
486 return false;
487
488 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
489 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
490 return true;
491
492 if (skb->ignore_df)
493 return false;
494
495 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
496 return false;
497
498 return true;
499}
500
501int ip6_forward(struct sk_buff *skb)
502{
503 struct dst_entry *dst = skb_dst(skb);
504 struct ipv6hdr *hdr = ipv6_hdr(skb);
505 struct inet6_skb_parm *opt = IP6CB(skb);
506 struct net *net = dev_net(dst->dev);
507 struct inet6_dev *idev;
508 SKB_DR(reason);
509 u32 mtu;
510
511 idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
512 if (READ_ONCE(net->ipv6.devconf_all->forwarding) == 0)
513 goto error;
514
515 if (skb->pkt_type != PACKET_HOST)
516 goto drop;
517
518 if (unlikely(skb->sk))
519 goto drop;
520
521 if (skb_warn_if_lro(skb))
522 goto drop;
523
524 if (!READ_ONCE(net->ipv6.devconf_all->disable_policy) &&
525 (!idev || !READ_ONCE(idev->cnf.disable_policy)) &&
526 !xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
527 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
528 goto drop;
529 }
530
531 skb_forward_csum(skb);
532
533 /*
534 * We DO NOT make any processing on
535 * RA packets, pushing them to user level AS IS
536 * without ane WARRANTY that application will be able
537 * to interpret them. The reason is that we
538 * cannot make anything clever here.
539 *
540 * We are not end-node, so that if packet contains
541 * AH/ESP, we cannot make anything.
542 * Defragmentation also would be mistake, RA packets
543 * cannot be fragmented, because there is no warranty
544 * that different fragments will go along one path. --ANK
545 */
546 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
547 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
548 return 0;
549 }
550
551 /*
552 * check and decrement ttl
553 */
554 if (hdr->hop_limit <= 1) {
555 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
556 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
557
558 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
559 return -ETIMEDOUT;
560 }
561
562 /* XXX: idev->cnf.proxy_ndp? */
563 if (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) &&
564 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
565 int proxied = ip6_forward_proxy_check(skb);
566 if (proxied > 0) {
567 /* It's tempting to decrease the hop limit
568 * here by 1, as we do at the end of the
569 * function too.
570 *
571 * But that would be incorrect, as proxying is
572 * not forwarding. The ip6_input function
573 * will handle this packet locally, and it
574 * depends on the hop limit being unchanged.
575 *
576 * One example is the NDP hop limit, that
577 * always has to stay 255, but other would be
578 * similar checks around RA packets, where the
579 * user can even change the desired limit.
580 */
581 return ip6_input(skb);
582 } else if (proxied < 0) {
583 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
584 goto drop;
585 }
586 }
587
588 if (!xfrm6_route_forward(skb)) {
589 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
590 SKB_DR_SET(reason, XFRM_POLICY);
591 goto drop;
592 }
593 dst = skb_dst(skb);
594
595 /* IPv6 specs say nothing about it, but it is clear that we cannot
596 send redirects to source routed frames.
597 We don't send redirects to frames decapsulated from IPsec.
598 */
599 if (IP6CB(skb)->iif == dst->dev->ifindex &&
600 opt->srcrt == 0 && !skb_sec_path(skb)) {
601 struct in6_addr *target = NULL;
602 struct inet_peer *peer;
603 struct rt6_info *rt;
604
605 /*
606 * incoming and outgoing devices are the same
607 * send a redirect.
608 */
609
610 rt = dst_rt6_info(dst);
611 if (rt->rt6i_flags & RTF_GATEWAY)
612 target = &rt->rt6i_gateway;
613 else
614 target = &hdr->daddr;
615
616 rcu_read_lock();
617 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr);
618
619 /* Limit redirects both by destination (here)
620 and by source (inside ndisc_send_redirect)
621 */
622 if (inet_peer_xrlim_allow(peer, 1*HZ))
623 ndisc_send_redirect(skb, target);
624 rcu_read_unlock();
625 } else {
626 int addrtype = ipv6_addr_type(&hdr->saddr);
627
628 /* This check is security critical. */
629 if (addrtype == IPV6_ADDR_ANY ||
630 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
631 goto error;
632 if (addrtype & IPV6_ADDR_LINKLOCAL) {
633 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
634 ICMPV6_NOT_NEIGHBOUR, 0);
635 goto error;
636 }
637 }
638
639 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
640
641 mtu = ip6_dst_mtu_maybe_forward(dst, true);
642 if (mtu < IPV6_MIN_MTU)
643 mtu = IPV6_MIN_MTU;
644
645 if (ip6_pkt_too_big(skb, mtu)) {
646 /* Again, force OUTPUT device used as source address */
647 skb->dev = dst->dev;
648 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
649 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
650 __IP6_INC_STATS(net, ip6_dst_idev(dst),
651 IPSTATS_MIB_FRAGFAILS);
652 kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
653 return -EMSGSIZE;
654 }
655
656 if (skb_cow(skb, dst->dev->hard_header_len)) {
657 __IP6_INC_STATS(net, ip6_dst_idev(dst),
658 IPSTATS_MIB_OUTDISCARDS);
659 goto drop;
660 }
661
662 hdr = ipv6_hdr(skb);
663
664 /* Mangling hops number delayed to point after skb COW */
665
666 hdr->hop_limit--;
667
668 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
669 net, NULL, skb, skb->dev, dst->dev,
670 ip6_forward_finish);
671
672error:
673 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
674 SKB_DR_SET(reason, IP_INADDRERRORS);
675drop:
676 kfree_skb_reason(skb, reason);
677 return -EINVAL;
678}
679
680static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
681{
682 to->pkt_type = from->pkt_type;
683 to->priority = from->priority;
684 to->protocol = from->protocol;
685 skb_dst_drop(to);
686 skb_dst_set(to, dst_clone(skb_dst(from)));
687 to->dev = from->dev;
688 to->mark = from->mark;
689
690 skb_copy_hash(to, from);
691
692#ifdef CONFIG_NET_SCHED
693 to->tc_index = from->tc_index;
694#endif
695 nf_copy(to, from);
696 skb_ext_copy(to, from);
697 skb_copy_secmark(to, from);
698}
699
700int ip6_fraglist_init(struct sk_buff *skb, unsigned int hlen, u8 *prevhdr,
701 u8 nexthdr, __be32 frag_id,
702 struct ip6_fraglist_iter *iter)
703{
704 unsigned int first_len;
705 struct frag_hdr *fh;
706
707 /* BUILD HEADER */
708 *prevhdr = NEXTHDR_FRAGMENT;
709 iter->tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
710 if (!iter->tmp_hdr)
711 return -ENOMEM;
712
713 iter->frag = skb_shinfo(skb)->frag_list;
714 skb_frag_list_init(skb);
715
716 iter->offset = 0;
717 iter->hlen = hlen;
718 iter->frag_id = frag_id;
719 iter->nexthdr = nexthdr;
720
721 __skb_pull(skb, hlen);
722 fh = __skb_push(skb, sizeof(struct frag_hdr));
723 __skb_push(skb, hlen);
724 skb_reset_network_header(skb);
725 memcpy(skb_network_header(skb), iter->tmp_hdr, hlen);
726
727 fh->nexthdr = nexthdr;
728 fh->reserved = 0;
729 fh->frag_off = htons(IP6_MF);
730 fh->identification = frag_id;
731
732 first_len = skb_pagelen(skb);
733 skb->data_len = first_len - skb_headlen(skb);
734 skb->len = first_len;
735 ipv6_hdr(skb)->payload_len = htons(first_len - sizeof(struct ipv6hdr));
736
737 return 0;
738}
739EXPORT_SYMBOL(ip6_fraglist_init);
740
741void ip6_fraglist_prepare(struct sk_buff *skb,
742 struct ip6_fraglist_iter *iter)
743{
744 struct sk_buff *frag = iter->frag;
745 unsigned int hlen = iter->hlen;
746 struct frag_hdr *fh;
747
748 frag->ip_summed = CHECKSUM_NONE;
749 skb_reset_transport_header(frag);
750 fh = __skb_push(frag, sizeof(struct frag_hdr));
751 __skb_push(frag, hlen);
752 skb_reset_network_header(frag);
753 memcpy(skb_network_header(frag), iter->tmp_hdr, hlen);
754 iter->offset += skb->len - hlen - sizeof(struct frag_hdr);
755 fh->nexthdr = iter->nexthdr;
756 fh->reserved = 0;
757 fh->frag_off = htons(iter->offset);
758 if (frag->next)
759 fh->frag_off |= htons(IP6_MF);
760 fh->identification = iter->frag_id;
761 ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
762 ip6_copy_metadata(frag, skb);
763}
764EXPORT_SYMBOL(ip6_fraglist_prepare);
765
766void ip6_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int mtu,
767 unsigned short needed_tailroom, int hdr_room, u8 *prevhdr,
768 u8 nexthdr, __be32 frag_id, struct ip6_frag_state *state)
769{
770 state->prevhdr = prevhdr;
771 state->nexthdr = nexthdr;
772 state->frag_id = frag_id;
773
774 state->hlen = hlen;
775 state->mtu = mtu;
776
777 state->left = skb->len - hlen; /* Space per frame */
778 state->ptr = hlen; /* Where to start from */
779
780 state->hroom = hdr_room;
781 state->troom = needed_tailroom;
782
783 state->offset = 0;
784}
785EXPORT_SYMBOL(ip6_frag_init);
786
787struct sk_buff *ip6_frag_next(struct sk_buff *skb, struct ip6_frag_state *state)
788{
789 u8 *prevhdr = state->prevhdr, *fragnexthdr_offset;
790 struct sk_buff *frag;
791 struct frag_hdr *fh;
792 unsigned int len;
793
794 len = state->left;
795 /* IF: it doesn't fit, use 'mtu' - the data space left */
796 if (len > state->mtu)
797 len = state->mtu;
798 /* IF: we are not sending up to and including the packet end
799 then align the next start on an eight byte boundary */
800 if (len < state->left)
801 len &= ~7;
802
803 /* Allocate buffer */
804 frag = alloc_skb(len + state->hlen + sizeof(struct frag_hdr) +
805 state->hroom + state->troom, GFP_ATOMIC);
806 if (!frag)
807 return ERR_PTR(-ENOMEM);
808
809 /*
810 * Set up data on packet
811 */
812
813 ip6_copy_metadata(frag, skb);
814 skb_reserve(frag, state->hroom);
815 skb_put(frag, len + state->hlen + sizeof(struct frag_hdr));
816 skb_reset_network_header(frag);
817 fh = (struct frag_hdr *)(skb_network_header(frag) + state->hlen);
818 frag->transport_header = (frag->network_header + state->hlen +
819 sizeof(struct frag_hdr));
820
821 /*
822 * Charge the memory for the fragment to any owner
823 * it might possess
824 */
825 if (skb->sk)
826 skb_set_owner_w(frag, skb->sk);
827
828 /*
829 * Copy the packet header into the new buffer.
830 */
831 skb_copy_from_linear_data(skb, skb_network_header(frag), state->hlen);
832
833 fragnexthdr_offset = skb_network_header(frag);
834 fragnexthdr_offset += prevhdr - skb_network_header(skb);
835 *fragnexthdr_offset = NEXTHDR_FRAGMENT;
836
837 /*
838 * Build fragment header.
839 */
840 fh->nexthdr = state->nexthdr;
841 fh->reserved = 0;
842 fh->identification = state->frag_id;
843
844 /*
845 * Copy a block of the IP datagram.
846 */
847 BUG_ON(skb_copy_bits(skb, state->ptr, skb_transport_header(frag),
848 len));
849 state->left -= len;
850
851 fh->frag_off = htons(state->offset);
852 if (state->left > 0)
853 fh->frag_off |= htons(IP6_MF);
854 ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
855
856 state->ptr += len;
857 state->offset += len;
858
859 return frag;
860}
861EXPORT_SYMBOL(ip6_frag_next);
862
863int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
864 int (*output)(struct net *, struct sock *, struct sk_buff *))
865{
866 struct sk_buff *frag;
867 struct rt6_info *rt = dst_rt6_info(skb_dst(skb));
868 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
869 inet6_sk(skb->sk) : NULL;
870 u8 tstamp_type = skb->tstamp_type;
871 struct ip6_frag_state state;
872 unsigned int mtu, hlen, nexthdr_offset;
873 ktime_t tstamp = skb->tstamp;
874 int hroom, err = 0;
875 __be32 frag_id;
876 u8 *prevhdr, nexthdr = 0;
877
878 err = ip6_find_1stfragopt(skb, &prevhdr);
879 if (err < 0)
880 goto fail;
881 hlen = err;
882 nexthdr = *prevhdr;
883 nexthdr_offset = prevhdr - skb_network_header(skb);
884
885 mtu = ip6_skb_dst_mtu(skb);
886
887 /* We must not fragment if the socket is set to force MTU discovery
888 * or if the skb it not generated by a local socket.
889 */
890 if (unlikely(!skb->ignore_df && skb->len > mtu))
891 goto fail_toobig;
892
893 if (IP6CB(skb)->frag_max_size) {
894 if (IP6CB(skb)->frag_max_size > mtu)
895 goto fail_toobig;
896
897 /* don't send fragments larger than what we received */
898 mtu = IP6CB(skb)->frag_max_size;
899 if (mtu < IPV6_MIN_MTU)
900 mtu = IPV6_MIN_MTU;
901 }
902
903 if (np) {
904 u32 frag_size = READ_ONCE(np->frag_size);
905
906 if (frag_size && frag_size < mtu)
907 mtu = frag_size;
908 }
909 if (mtu < hlen + sizeof(struct frag_hdr) + 8)
910 goto fail_toobig;
911 mtu -= hlen + sizeof(struct frag_hdr);
912
913 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
914 &ipv6_hdr(skb)->saddr);
915
916 if (skb->ip_summed == CHECKSUM_PARTIAL &&
917 (err = skb_checksum_help(skb)))
918 goto fail;
919
920 prevhdr = skb_network_header(skb) + nexthdr_offset;
921 hroom = LL_RESERVED_SPACE(rt->dst.dev);
922 if (skb_has_frag_list(skb)) {
923 unsigned int first_len = skb_pagelen(skb);
924 struct ip6_fraglist_iter iter;
925 struct sk_buff *frag2;
926
927 if (first_len - hlen > mtu ||
928 ((first_len - hlen) & 7) ||
929 skb_cloned(skb) ||
930 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
931 goto slow_path;
932
933 skb_walk_frags(skb, frag) {
934 /* Correct geometry. */
935 if (frag->len > mtu ||
936 ((frag->len & 7) && frag->next) ||
937 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
938 goto slow_path_clean;
939
940 /* Partially cloned skb? */
941 if (skb_shared(frag))
942 goto slow_path_clean;
943
944 BUG_ON(frag->sk);
945 if (skb->sk) {
946 frag->sk = skb->sk;
947 frag->destructor = sock_wfree;
948 }
949 skb->truesize -= frag->truesize;
950 }
951
952 err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
953 &iter);
954 if (err < 0)
955 goto fail;
956
957 /* We prevent @rt from being freed. */
958 rcu_read_lock();
959
960 for (;;) {
961 /* Prepare header of the next frame,
962 * before previous one went down. */
963 if (iter.frag)
964 ip6_fraglist_prepare(skb, &iter);
965
966 skb_set_delivery_time(skb, tstamp, tstamp_type);
967 err = output(net, sk, skb);
968 if (!err)
969 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
970 IPSTATS_MIB_FRAGCREATES);
971
972 if (err || !iter.frag)
973 break;
974
975 skb = ip6_fraglist_next(&iter);
976 }
977
978 kfree(iter.tmp_hdr);
979
980 if (err == 0) {
981 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
982 IPSTATS_MIB_FRAGOKS);
983 rcu_read_unlock();
984 return 0;
985 }
986
987 kfree_skb_list(iter.frag);
988
989 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
990 IPSTATS_MIB_FRAGFAILS);
991 rcu_read_unlock();
992 return err;
993
994slow_path_clean:
995 skb_walk_frags(skb, frag2) {
996 if (frag2 == frag)
997 break;
998 frag2->sk = NULL;
999 frag2->destructor = NULL;
1000 skb->truesize += frag2->truesize;
1001 }
1002 }
1003
1004slow_path:
1005 /*
1006 * Fragment the datagram.
1007 */
1008
1009 ip6_frag_init(skb, hlen, mtu, rt->dst.dev->needed_tailroom,
1010 LL_RESERVED_SPACE(rt->dst.dev), prevhdr, nexthdr, frag_id,
1011 &state);
1012
1013 /*
1014 * Keep copying data until we run out.
1015 */
1016
1017 while (state.left > 0) {
1018 frag = ip6_frag_next(skb, &state);
1019 if (IS_ERR(frag)) {
1020 err = PTR_ERR(frag);
1021 goto fail;
1022 }
1023
1024 /*
1025 * Put this fragment into the sending queue.
1026 */
1027 skb_set_delivery_time(frag, tstamp, tstamp_type);
1028 err = output(net, sk, frag);
1029 if (err)
1030 goto fail;
1031
1032 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1033 IPSTATS_MIB_FRAGCREATES);
1034 }
1035 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1036 IPSTATS_MIB_FRAGOKS);
1037 consume_skb(skb);
1038 return err;
1039
1040fail_toobig:
1041 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1042 err = -EMSGSIZE;
1043
1044fail:
1045 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1046 IPSTATS_MIB_FRAGFAILS);
1047 kfree_skb(skb);
1048 return err;
1049}
1050
1051static inline int ip6_rt_check(const struct rt6key *rt_key,
1052 const struct in6_addr *fl_addr,
1053 const struct in6_addr *addr_cache)
1054{
1055 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
1056 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
1057}
1058
1059static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
1060 struct dst_entry *dst,
1061 const struct flowi6 *fl6)
1062{
1063 struct ipv6_pinfo *np = inet6_sk(sk);
1064 struct rt6_info *rt;
1065
1066 if (!dst)
1067 goto out;
1068
1069 if (dst->ops->family != AF_INET6) {
1070 dst_release(dst);
1071 return NULL;
1072 }
1073
1074 rt = dst_rt6_info(dst);
1075 /* Yes, checking route validity in not connected
1076 * case is not very simple. Take into account,
1077 * that we do not support routing by source, TOS,
1078 * and MSG_DONTROUTE --ANK (980726)
1079 *
1080 * 1. ip6_rt_check(): If route was host route,
1081 * check that cached destination is current.
1082 * If it is network route, we still may
1083 * check its validity using saved pointer
1084 * to the last used address: daddr_cache.
1085 * We do not want to save whole address now,
1086 * (because main consumer of this service
1087 * is tcp, which has not this problem),
1088 * so that the last trick works only on connected
1089 * sockets.
1090 * 2. oif also should be the same.
1091 */
1092 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
1093#ifdef CONFIG_IPV6_SUBTREES
1094 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
1095#endif
1096 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
1097 dst_release(dst);
1098 dst = NULL;
1099 }
1100
1101out:
1102 return dst;
1103}
1104
1105static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
1106 struct dst_entry **dst, struct flowi6 *fl6)
1107{
1108#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
1109 struct neighbour *n;
1110 struct rt6_info *rt;
1111#endif
1112 int err;
1113 int flags = 0;
1114
1115 /* The correct way to handle this would be to do
1116 * ip6_route_get_saddr, and then ip6_route_output; however,
1117 * the route-specific preferred source forces the
1118 * ip6_route_output call _before_ ip6_route_get_saddr.
1119 *
1120 * In source specific routing (no src=any default route),
1121 * ip6_route_output will fail given src=any saddr, though, so
1122 * that's why we try it again later.
1123 */
1124 if (ipv6_addr_any(&fl6->saddr)) {
1125 struct fib6_info *from;
1126 struct rt6_info *rt;
1127
1128 *dst = ip6_route_output(net, sk, fl6);
1129 rt = (*dst)->error ? NULL : dst_rt6_info(*dst);
1130
1131 rcu_read_lock();
1132 from = rt ? rcu_dereference(rt->from) : NULL;
1133 err = ip6_route_get_saddr(net, from, &fl6->daddr,
1134 sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0,
1135 fl6->flowi6_l3mdev,
1136 &fl6->saddr);
1137 rcu_read_unlock();
1138
1139 if (err)
1140 goto out_err_release;
1141
1142 /* If we had an erroneous initial result, pretend it
1143 * never existed and let the SA-enabled version take
1144 * over.
1145 */
1146 if ((*dst)->error) {
1147 dst_release(*dst);
1148 *dst = NULL;
1149 }
1150
1151 if (fl6->flowi6_oif)
1152 flags |= RT6_LOOKUP_F_IFACE;
1153 }
1154
1155 if (!*dst)
1156 *dst = ip6_route_output_flags(net, sk, fl6, flags);
1157
1158 err = (*dst)->error;
1159 if (err)
1160 goto out_err_release;
1161
1162#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
1163 /*
1164 * Here if the dst entry we've looked up
1165 * has a neighbour entry that is in the INCOMPLETE
1166 * state and the src address from the flow is
1167 * marked as OPTIMISTIC, we release the found
1168 * dst entry and replace it instead with the
1169 * dst entry of the nexthop router
1170 */
1171 rt = dst_rt6_info(*dst);
1172 rcu_read_lock();
1173 n = __ipv6_neigh_lookup_noref(rt->dst.dev,
1174 rt6_nexthop(rt, &fl6->daddr));
1175 err = n && !(READ_ONCE(n->nud_state) & NUD_VALID) ? -EINVAL : 0;
1176 rcu_read_unlock();
1177
1178 if (err) {
1179 struct inet6_ifaddr *ifp;
1180 struct flowi6 fl_gw6;
1181 int redirect;
1182
1183 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
1184 (*dst)->dev, 1);
1185
1186 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
1187 if (ifp)
1188 in6_ifa_put(ifp);
1189
1190 if (redirect) {
1191 /*
1192 * We need to get the dst entry for the
1193 * default router instead
1194 */
1195 dst_release(*dst);
1196 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1197 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1198 *dst = ip6_route_output(net, sk, &fl_gw6);
1199 err = (*dst)->error;
1200 if (err)
1201 goto out_err_release;
1202 }
1203 }
1204#endif
1205 if (ipv6_addr_v4mapped(&fl6->saddr) &&
1206 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
1207 err = -EAFNOSUPPORT;
1208 goto out_err_release;
1209 }
1210
1211 return 0;
1212
1213out_err_release:
1214 dst_release(*dst);
1215 *dst = NULL;
1216
1217 if (err == -ENETUNREACH)
1218 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1219 return err;
1220}
1221
1222/**
1223 * ip6_dst_lookup - perform route lookup on flow
1224 * @net: Network namespace to perform lookup in
1225 * @sk: socket which provides route info
1226 * @dst: pointer to dst_entry * for result
1227 * @fl6: flow to lookup
1228 *
1229 * This function performs a route lookup on the given flow.
1230 *
1231 * It returns zero on success, or a standard errno code on error.
1232 */
1233int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1234 struct flowi6 *fl6)
1235{
1236 *dst = NULL;
1237 return ip6_dst_lookup_tail(net, sk, dst, fl6);
1238}
1239EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1240
1241/**
1242 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1243 * @net: Network namespace to perform lookup in
1244 * @sk: socket which provides route info
1245 * @fl6: flow to lookup
1246 * @final_dst: final destination address for ipsec lookup
1247 *
1248 * This function performs a route lookup on the given flow.
1249 *
1250 * It returns a valid dst pointer on success, or a pointer encoded
1251 * error code.
1252 */
1253struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
1254 const struct in6_addr *final_dst)
1255{
1256 struct dst_entry *dst = NULL;
1257 int err;
1258
1259 err = ip6_dst_lookup_tail(net, sk, &dst, fl6);
1260 if (err)
1261 return ERR_PTR(err);
1262 if (final_dst)
1263 fl6->daddr = *final_dst;
1264
1265 return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0);
1266}
1267EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1268
1269/**
1270 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1271 * @sk: socket which provides the dst cache and route info
1272 * @fl6: flow to lookup
1273 * @final_dst: final destination address for ipsec lookup
1274 * @connected: whether @sk is connected or not
1275 *
1276 * This function performs a route lookup on the given flow with the
1277 * possibility of using the cached route in the socket if it is valid.
1278 * It will take the socket dst lock when operating on the dst cache.
1279 * As a result, this function can only be used in process context.
1280 *
1281 * In addition, for a connected socket, cache the dst in the socket
1282 * if the current cache is not valid.
1283 *
1284 * It returns a valid dst pointer on success, or a pointer encoded
1285 * error code.
1286 */
1287struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1288 const struct in6_addr *final_dst,
1289 bool connected)
1290{
1291 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1292
1293 dst = ip6_sk_dst_check(sk, dst, fl6);
1294 if (dst)
1295 return dst;
1296
1297 dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst);
1298 if (connected && !IS_ERR(dst))
1299 ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6);
1300
1301 return dst;
1302}
1303EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1304
1305static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1306 gfp_t gfp)
1307{
1308 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1309}
1310
1311static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1312 gfp_t gfp)
1313{
1314 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1315}
1316
1317static void ip6_append_data_mtu(unsigned int *mtu,
1318 int *maxfraglen,
1319 unsigned int fragheaderlen,
1320 struct sk_buff *skb,
1321 struct rt6_info *rt,
1322 unsigned int orig_mtu)
1323{
1324 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1325 if (!skb) {
1326 /* first fragment, reserve header_len */
1327 *mtu = orig_mtu - rt->dst.header_len;
1328
1329 } else {
1330 /*
1331 * this fragment is not first, the headers
1332 * space is regarded as data space.
1333 */
1334 *mtu = orig_mtu;
1335 }
1336 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1337 + fragheaderlen - sizeof(struct frag_hdr);
1338 }
1339}
1340
1341static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1342 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1343 struct rt6_info *rt)
1344{
1345 struct ipv6_pinfo *np = inet6_sk(sk);
1346 unsigned int mtu, frag_size;
1347 struct ipv6_txoptions *nopt, *opt = ipc6->opt;
1348
1349 /* callers pass dst together with a reference, set it first so
1350 * ip6_cork_release() can put it down even in case of an error.
1351 */
1352 cork->base.dst = &rt->dst;
1353
1354 /*
1355 * setup for corking
1356 */
1357 if (opt) {
1358 if (WARN_ON(v6_cork->opt))
1359 return -EINVAL;
1360
1361 nopt = v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation);
1362 if (unlikely(!nopt))
1363 return -ENOBUFS;
1364
1365 nopt->tot_len = sizeof(*opt);
1366 nopt->opt_flen = opt->opt_flen;
1367 nopt->opt_nflen = opt->opt_nflen;
1368
1369 nopt->dst0opt = ip6_opt_dup(opt->dst0opt, sk->sk_allocation);
1370 if (opt->dst0opt && !nopt->dst0opt)
1371 return -ENOBUFS;
1372
1373 nopt->dst1opt = ip6_opt_dup(opt->dst1opt, sk->sk_allocation);
1374 if (opt->dst1opt && !nopt->dst1opt)
1375 return -ENOBUFS;
1376
1377 nopt->hopopt = ip6_opt_dup(opt->hopopt, sk->sk_allocation);
1378 if (opt->hopopt && !nopt->hopopt)
1379 return -ENOBUFS;
1380
1381 nopt->srcrt = ip6_rthdr_dup(opt->srcrt, sk->sk_allocation);
1382 if (opt->srcrt && !nopt->srcrt)
1383 return -ENOBUFS;
1384
1385 /* need source address above miyazawa*/
1386 }
1387 v6_cork->hop_limit = ipc6->hlimit;
1388 v6_cork->tclass = ipc6->tclass;
1389 if (rt->dst.flags & DST_XFRM_TUNNEL)
1390 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1391 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
1392 else
1393 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1394 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
1395
1396 frag_size = READ_ONCE(np->frag_size);
1397 if (frag_size && frag_size < mtu)
1398 mtu = frag_size;
1399
1400 cork->base.fragsize = mtu;
1401 cork->base.gso_size = ipc6->gso_size;
1402 cork->base.tx_flags = 0;
1403 cork->base.mark = ipc6->sockc.mark;
1404 sock_tx_timestamp(sk, &ipc6->sockc, &cork->base.tx_flags);
1405 if (ipc6->sockc.tsflags & SOCKCM_FLAG_TS_OPT_ID) {
1406 cork->base.flags |= IPCORK_TS_OPT_ID;
1407 cork->base.ts_opt_id = ipc6->sockc.ts_opt_id;
1408 }
1409 cork->base.length = 0;
1410 cork->base.transmit_time = ipc6->sockc.transmit_time;
1411
1412 return 0;
1413}
1414
1415static int __ip6_append_data(struct sock *sk,
1416 struct sk_buff_head *queue,
1417 struct inet_cork_full *cork_full,
1418 struct inet6_cork *v6_cork,
1419 struct page_frag *pfrag,
1420 int getfrag(void *from, char *to, int offset,
1421 int len, int odd, struct sk_buff *skb),
1422 void *from, size_t length, int transhdrlen,
1423 unsigned int flags, struct ipcm6_cookie *ipc6)
1424{
1425 struct sk_buff *skb, *skb_prev = NULL;
1426 struct inet_cork *cork = &cork_full->base;
1427 struct flowi6 *fl6 = &cork_full->fl.u.ip6;
1428 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
1429 struct ubuf_info *uarg = NULL;
1430 int exthdrlen = 0;
1431 int dst_exthdrlen = 0;
1432 int hh_len;
1433 int copy;
1434 int err;
1435 int offset = 0;
1436 bool zc = false;
1437 u32 tskey = 0;
1438 struct rt6_info *rt = dst_rt6_info(cork->dst);
1439 bool paged, hold_tskey = false, extra_uref = false;
1440 struct ipv6_txoptions *opt = v6_cork->opt;
1441 int csummode = CHECKSUM_NONE;
1442 unsigned int maxnonfragsize, headersize;
1443 unsigned int wmem_alloc_delta = 0;
1444
1445 skb = skb_peek_tail(queue);
1446 if (!skb) {
1447 exthdrlen = opt ? opt->opt_flen : 0;
1448 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1449 }
1450
1451 paged = !!cork->gso_size;
1452 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
1453 orig_mtu = mtu;
1454
1455 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1456
1457 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1458 (opt ? opt->opt_nflen : 0);
1459
1460 headersize = sizeof(struct ipv6hdr) +
1461 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1462 rt->rt6i_nfheader_len;
1463
1464 if (mtu <= fragheaderlen ||
1465 ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
1466 goto emsgsize;
1467
1468 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1469 sizeof(struct frag_hdr);
1470
1471 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit
1472 * the first fragment
1473 */
1474 if (headersize + transhdrlen > mtu)
1475 goto emsgsize;
1476
1477 if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1478 (sk->sk_protocol == IPPROTO_UDP ||
1479 sk->sk_protocol == IPPROTO_ICMPV6 ||
1480 sk->sk_protocol == IPPROTO_RAW)) {
1481 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1482 sizeof(struct ipv6hdr));
1483 goto emsgsize;
1484 }
1485
1486 if (ip6_sk_ignore_df(sk))
1487 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1488 else
1489 maxnonfragsize = mtu;
1490
1491 if (cork->length + length > maxnonfragsize - headersize) {
1492emsgsize:
1493 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
1494 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu);
1495 return -EMSGSIZE;
1496 }
1497
1498 /* CHECKSUM_PARTIAL only with no extension headers and when
1499 * we are not going to fragment
1500 */
1501 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1502 headersize == sizeof(struct ipv6hdr) &&
1503 length <= mtu - headersize &&
1504 (!(flags & MSG_MORE) || cork->gso_size) &&
1505 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1506 csummode = CHECKSUM_PARTIAL;
1507
1508 if ((flags & MSG_ZEROCOPY) && length) {
1509 struct msghdr *msg = from;
1510
1511 if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {
1512 if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))
1513 return -EINVAL;
1514
1515 /* Leave uarg NULL if can't zerocopy, callers should
1516 * be able to handle it.
1517 */
1518 if ((rt->dst.dev->features & NETIF_F_SG) &&
1519 csummode == CHECKSUM_PARTIAL) {
1520 paged = true;
1521 zc = true;
1522 uarg = msg->msg_ubuf;
1523 }
1524 } else if (sock_flag(sk, SOCK_ZEROCOPY)) {
1525 uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
1526 if (!uarg)
1527 return -ENOBUFS;
1528 extra_uref = !skb_zcopy(skb); /* only ref on new uarg */
1529 if (rt->dst.dev->features & NETIF_F_SG &&
1530 csummode == CHECKSUM_PARTIAL) {
1531 paged = true;
1532 zc = true;
1533 } else {
1534 uarg_to_msgzc(uarg)->zerocopy = 0;
1535 skb_zcopy_set(skb, uarg, &extra_uref);
1536 }
1537 }
1538 } else if ((flags & MSG_SPLICE_PAGES) && length) {
1539 if (inet_test_bit(HDRINCL, sk))
1540 return -EPERM;
1541 if (rt->dst.dev->features & NETIF_F_SG &&
1542 getfrag == ip_generic_getfrag)
1543 /* We need an empty buffer to attach stuff to */
1544 paged = true;
1545 else
1546 flags &= ~MSG_SPLICE_PAGES;
1547 }
1548
1549 if (cork->tx_flags & SKBTX_ANY_TSTAMP &&
1550 READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) {
1551 if (cork->flags & IPCORK_TS_OPT_ID) {
1552 tskey = cork->ts_opt_id;
1553 } else {
1554 tskey = atomic_inc_return(&sk->sk_tskey) - 1;
1555 hold_tskey = true;
1556 }
1557 }
1558
1559 /*
1560 * Let's try using as much space as possible.
1561 * Use MTU if total length of the message fits into the MTU.
1562 * Otherwise, we need to reserve fragment header and
1563 * fragment alignment (= 8-15 octects, in total).
1564 *
1565 * Note that we may need to "move" the data from the tail
1566 * of the buffer to the new fragment when we split
1567 * the message.
1568 *
1569 * FIXME: It may be fragmented into multiple chunks
1570 * at once if non-fragmentable extension headers
1571 * are too large.
1572 * --yoshfuji
1573 */
1574
1575 cork->length += length;
1576 if (!skb)
1577 goto alloc_new_skb;
1578
1579 while (length > 0) {
1580 /* Check if the remaining data fits into current packet. */
1581 copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len;
1582 if (copy < length)
1583 copy = maxfraglen - skb->len;
1584
1585 if (copy <= 0) {
1586 char *data;
1587 unsigned int datalen;
1588 unsigned int fraglen;
1589 unsigned int fraggap;
1590 unsigned int alloclen, alloc_extra;
1591 unsigned int pagedlen;
1592alloc_new_skb:
1593 /* There's no room in the current skb */
1594 if (skb)
1595 fraggap = skb->len - maxfraglen;
1596 else
1597 fraggap = 0;
1598 /* update mtu and maxfraglen if necessary */
1599 if (!skb || !skb_prev)
1600 ip6_append_data_mtu(&mtu, &maxfraglen,
1601 fragheaderlen, skb, rt,
1602 orig_mtu);
1603
1604 skb_prev = skb;
1605
1606 /*
1607 * If remaining data exceeds the mtu,
1608 * we know we need more fragment(s).
1609 */
1610 datalen = length + fraggap;
1611
1612 if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen)
1613 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1614 fraglen = datalen + fragheaderlen;
1615 pagedlen = 0;
1616
1617 alloc_extra = hh_len;
1618 alloc_extra += dst_exthdrlen;
1619 alloc_extra += rt->dst.trailer_len;
1620
1621 /* We just reserve space for fragment header.
1622 * Note: this may be overallocation if the message
1623 * (without MSG_MORE) fits into the MTU.
1624 */
1625 alloc_extra += sizeof(struct frag_hdr);
1626
1627 if ((flags & MSG_MORE) &&
1628 !(rt->dst.dev->features&NETIF_F_SG))
1629 alloclen = mtu;
1630 else if (!paged &&
1631 (fraglen + alloc_extra < SKB_MAX_ALLOC ||
1632 !(rt->dst.dev->features & NETIF_F_SG)))
1633 alloclen = fraglen;
1634 else {
1635 alloclen = fragheaderlen + transhdrlen;
1636 pagedlen = datalen - transhdrlen;
1637 }
1638 alloclen += alloc_extra;
1639
1640 if (datalen != length + fraggap) {
1641 /*
1642 * this is not the last fragment, the trailer
1643 * space is regarded as data space.
1644 */
1645 datalen += rt->dst.trailer_len;
1646 }
1647
1648 fraglen = datalen + fragheaderlen;
1649
1650 copy = datalen - transhdrlen - fraggap - pagedlen;
1651 /* [!] NOTE: copy may be negative if pagedlen>0
1652 * because then the equation may reduces to -fraggap.
1653 */
1654 if (copy < 0 && !(flags & MSG_SPLICE_PAGES)) {
1655 err = -EINVAL;
1656 goto error;
1657 }
1658 if (transhdrlen) {
1659 skb = sock_alloc_send_skb(sk, alloclen,
1660 (flags & MSG_DONTWAIT), &err);
1661 } else {
1662 skb = NULL;
1663 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
1664 2 * sk->sk_sndbuf)
1665 skb = alloc_skb(alloclen,
1666 sk->sk_allocation);
1667 if (unlikely(!skb))
1668 err = -ENOBUFS;
1669 }
1670 if (!skb)
1671 goto error;
1672 /*
1673 * Fill in the control structures
1674 */
1675 skb->protocol = htons(ETH_P_IPV6);
1676 skb->ip_summed = csummode;
1677 skb->csum = 0;
1678 /* reserve for fragmentation and ipsec header */
1679 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1680 dst_exthdrlen);
1681
1682 /*
1683 * Find where to start putting bytes
1684 */
1685 data = skb_put(skb, fraglen - pagedlen);
1686 skb_set_network_header(skb, exthdrlen);
1687 data += fragheaderlen;
1688 skb->transport_header = (skb->network_header +
1689 fragheaderlen);
1690 if (fraggap) {
1691 skb->csum = skb_copy_and_csum_bits(
1692 skb_prev, maxfraglen,
1693 data + transhdrlen, fraggap);
1694 skb_prev->csum = csum_sub(skb_prev->csum,
1695 skb->csum);
1696 data += fraggap;
1697 pskb_trim_unique(skb_prev, maxfraglen);
1698 }
1699 if (copy > 0 &&
1700 getfrag(from, data + transhdrlen, offset,
1701 copy, fraggap, skb) < 0) {
1702 err = -EFAULT;
1703 kfree_skb(skb);
1704 goto error;
1705 } else if (flags & MSG_SPLICE_PAGES) {
1706 copy = 0;
1707 }
1708
1709 offset += copy;
1710 length -= copy + transhdrlen;
1711 transhdrlen = 0;
1712 exthdrlen = 0;
1713 dst_exthdrlen = 0;
1714
1715 /* Only the initial fragment is time stamped */
1716 skb_shinfo(skb)->tx_flags = cork->tx_flags;
1717 cork->tx_flags = 0;
1718 skb_shinfo(skb)->tskey = tskey;
1719 tskey = 0;
1720 skb_zcopy_set(skb, uarg, &extra_uref);
1721
1722 if ((flags & MSG_CONFIRM) && !skb_prev)
1723 skb_set_dst_pending_confirm(skb, 1);
1724
1725 /*
1726 * Put the packet on the pending queue
1727 */
1728 if (!skb->destructor) {
1729 skb->destructor = sock_wfree;
1730 skb->sk = sk;
1731 wmem_alloc_delta += skb->truesize;
1732 }
1733 __skb_queue_tail(queue, skb);
1734 continue;
1735 }
1736
1737 if (copy > length)
1738 copy = length;
1739
1740 if (!(rt->dst.dev->features&NETIF_F_SG) &&
1741 skb_tailroom(skb) >= copy) {
1742 unsigned int off;
1743
1744 off = skb->len;
1745 if (getfrag(from, skb_put(skb, copy),
1746 offset, copy, off, skb) < 0) {
1747 __skb_trim(skb, off);
1748 err = -EFAULT;
1749 goto error;
1750 }
1751 } else if (flags & MSG_SPLICE_PAGES) {
1752 struct msghdr *msg = from;
1753
1754 err = -EIO;
1755 if (WARN_ON_ONCE(copy > msg->msg_iter.count))
1756 goto error;
1757
1758 err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
1759 sk->sk_allocation);
1760 if (err < 0)
1761 goto error;
1762 copy = err;
1763 wmem_alloc_delta += copy;
1764 } else if (!zc) {
1765 int i = skb_shinfo(skb)->nr_frags;
1766
1767 err = -ENOMEM;
1768 if (!sk_page_frag_refill(sk, pfrag))
1769 goto error;
1770
1771 skb_zcopy_downgrade_managed(skb);
1772 if (!skb_can_coalesce(skb, i, pfrag->page,
1773 pfrag->offset)) {
1774 err = -EMSGSIZE;
1775 if (i == MAX_SKB_FRAGS)
1776 goto error;
1777
1778 __skb_fill_page_desc(skb, i, pfrag->page,
1779 pfrag->offset, 0);
1780 skb_shinfo(skb)->nr_frags = ++i;
1781 get_page(pfrag->page);
1782 }
1783 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1784 if (getfrag(from,
1785 page_address(pfrag->page) + pfrag->offset,
1786 offset, copy, skb->len, skb) < 0)
1787 goto error_efault;
1788
1789 pfrag->offset += copy;
1790 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1791 skb->len += copy;
1792 skb->data_len += copy;
1793 skb->truesize += copy;
1794 wmem_alloc_delta += copy;
1795 } else {
1796 err = skb_zerocopy_iter_dgram(skb, from, copy);
1797 if (err < 0)
1798 goto error;
1799 }
1800 offset += copy;
1801 length -= copy;
1802 }
1803
1804 if (wmem_alloc_delta)
1805 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1806 return 0;
1807
1808error_efault:
1809 err = -EFAULT;
1810error:
1811 net_zcopy_put_abort(uarg, extra_uref);
1812 cork->length -= length;
1813 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1814 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1815 if (hold_tskey)
1816 atomic_dec(&sk->sk_tskey);
1817 return err;
1818}
1819
1820int ip6_append_data(struct sock *sk,
1821 int getfrag(void *from, char *to, int offset, int len,
1822 int odd, struct sk_buff *skb),
1823 void *from, size_t length, int transhdrlen,
1824 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1825 struct rt6_info *rt, unsigned int flags)
1826{
1827 struct inet_sock *inet = inet_sk(sk);
1828 struct ipv6_pinfo *np = inet6_sk(sk);
1829 int exthdrlen;
1830 int err;
1831
1832 if (flags&MSG_PROBE)
1833 return 0;
1834 if (skb_queue_empty(&sk->sk_write_queue)) {
1835 /*
1836 * setup for corking
1837 */
1838 dst_hold(&rt->dst);
1839 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1840 ipc6, rt);
1841 if (err)
1842 return err;
1843
1844 inet->cork.fl.u.ip6 = *fl6;
1845 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1846 length += exthdrlen;
1847 transhdrlen += exthdrlen;
1848 } else {
1849 transhdrlen = 0;
1850 }
1851
1852 return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,
1853 &np->cork, sk_page_frag(sk), getfrag,
1854 from, length, transhdrlen, flags, ipc6);
1855}
1856EXPORT_SYMBOL_GPL(ip6_append_data);
1857
1858static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork)
1859{
1860 struct dst_entry *dst = cork->base.dst;
1861
1862 cork->base.dst = NULL;
1863 skb_dst_set(skb, dst);
1864}
1865
1866static void ip6_cork_release(struct inet_cork_full *cork,
1867 struct inet6_cork *v6_cork)
1868{
1869 if (v6_cork->opt) {
1870 struct ipv6_txoptions *opt = v6_cork->opt;
1871
1872 kfree(opt->dst0opt);
1873 kfree(opt->dst1opt);
1874 kfree(opt->hopopt);
1875 kfree(opt->srcrt);
1876 kfree(opt);
1877 v6_cork->opt = NULL;
1878 }
1879
1880 if (cork->base.dst) {
1881 dst_release(cork->base.dst);
1882 cork->base.dst = NULL;
1883 }
1884}
1885
1886struct sk_buff *__ip6_make_skb(struct sock *sk,
1887 struct sk_buff_head *queue,
1888 struct inet_cork_full *cork,
1889 struct inet6_cork *v6_cork)
1890{
1891 struct sk_buff *skb, *tmp_skb;
1892 struct sk_buff **tail_skb;
1893 struct in6_addr *final_dst;
1894 struct net *net = sock_net(sk);
1895 struct ipv6hdr *hdr;
1896 struct ipv6_txoptions *opt = v6_cork->opt;
1897 struct rt6_info *rt = dst_rt6_info(cork->base.dst);
1898 struct flowi6 *fl6 = &cork->fl.u.ip6;
1899 unsigned char proto = fl6->flowi6_proto;
1900
1901 skb = __skb_dequeue(queue);
1902 if (!skb)
1903 goto out;
1904 tail_skb = &(skb_shinfo(skb)->frag_list);
1905
1906 /* move skb->data to ip header from ext header */
1907 if (skb->data < skb_network_header(skb))
1908 __skb_pull(skb, skb_network_offset(skb));
1909 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1910 __skb_pull(tmp_skb, skb_network_header_len(skb));
1911 *tail_skb = tmp_skb;
1912 tail_skb = &(tmp_skb->next);
1913 skb->len += tmp_skb->len;
1914 skb->data_len += tmp_skb->len;
1915 skb->truesize += tmp_skb->truesize;
1916 tmp_skb->destructor = NULL;
1917 tmp_skb->sk = NULL;
1918 }
1919
1920 /* Allow local fragmentation. */
1921 skb->ignore_df = ip6_sk_ignore_df(sk);
1922 __skb_pull(skb, skb_network_header_len(skb));
1923
1924 final_dst = &fl6->daddr;
1925 if (opt && opt->opt_flen)
1926 ipv6_push_frag_opts(skb, opt, &proto);
1927 if (opt && opt->opt_nflen)
1928 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1929
1930 skb_push(skb, sizeof(struct ipv6hdr));
1931 skb_reset_network_header(skb);
1932 hdr = ipv6_hdr(skb);
1933
1934 ip6_flow_hdr(hdr, v6_cork->tclass,
1935 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1936 ip6_autoflowlabel(net, sk), fl6));
1937 hdr->hop_limit = v6_cork->hop_limit;
1938 hdr->nexthdr = proto;
1939 hdr->saddr = fl6->saddr;
1940 hdr->daddr = *final_dst;
1941
1942 skb->priority = READ_ONCE(sk->sk_priority);
1943 skb->mark = cork->base.mark;
1944 if (sk_is_tcp(sk))
1945 skb_set_delivery_time(skb, cork->base.transmit_time, SKB_CLOCK_MONOTONIC);
1946 else
1947 skb_set_delivery_type_by_clockid(skb, cork->base.transmit_time, sk->sk_clockid);
1948
1949 ip6_cork_steal_dst(skb, cork);
1950 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
1951 if (proto == IPPROTO_ICMPV6) {
1952 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1953 u8 icmp6_type;
1954
1955 if (sk->sk_socket->type == SOCK_RAW &&
1956 !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH))
1957 icmp6_type = fl6->fl6_icmp_type;
1958 else
1959 icmp6_type = icmp6_hdr(skb)->icmp6_type;
1960 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type);
1961 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1962 }
1963
1964 ip6_cork_release(cork, v6_cork);
1965out:
1966 return skb;
1967}
1968
1969int ip6_send_skb(struct sk_buff *skb)
1970{
1971 struct net *net = sock_net(skb->sk);
1972 struct rt6_info *rt = dst_rt6_info(skb_dst(skb));
1973 int err;
1974
1975 rcu_read_lock();
1976 err = ip6_local_out(net, skb->sk, skb);
1977 if (err) {
1978 if (err > 0)
1979 err = net_xmit_errno(err);
1980 if (err)
1981 IP6_INC_STATS(net, rt->rt6i_idev,
1982 IPSTATS_MIB_OUTDISCARDS);
1983 }
1984
1985 rcu_read_unlock();
1986 return err;
1987}
1988
1989int ip6_push_pending_frames(struct sock *sk)
1990{
1991 struct sk_buff *skb;
1992
1993 skb = ip6_finish_skb(sk);
1994 if (!skb)
1995 return 0;
1996
1997 return ip6_send_skb(skb);
1998}
1999EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
2000
2001static void __ip6_flush_pending_frames(struct sock *sk,
2002 struct sk_buff_head *queue,
2003 struct inet_cork_full *cork,
2004 struct inet6_cork *v6_cork)
2005{
2006 struct sk_buff *skb;
2007
2008 while ((skb = __skb_dequeue_tail(queue)) != NULL) {
2009 if (skb_dst(skb))
2010 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
2011 IPSTATS_MIB_OUTDISCARDS);
2012 kfree_skb(skb);
2013 }
2014
2015 ip6_cork_release(cork, v6_cork);
2016}
2017
2018void ip6_flush_pending_frames(struct sock *sk)
2019{
2020 __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
2021 &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
2022}
2023EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
2024
2025struct sk_buff *ip6_make_skb(struct sock *sk,
2026 int getfrag(void *from, char *to, int offset,
2027 int len, int odd, struct sk_buff *skb),
2028 void *from, size_t length, int transhdrlen,
2029 struct ipcm6_cookie *ipc6, struct rt6_info *rt,
2030 unsigned int flags, struct inet_cork_full *cork)
2031{
2032 struct inet6_cork v6_cork;
2033 struct sk_buff_head queue;
2034 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
2035 int err;
2036
2037 if (flags & MSG_PROBE) {
2038 dst_release(&rt->dst);
2039 return NULL;
2040 }
2041
2042 __skb_queue_head_init(&queue);
2043
2044 cork->base.flags = 0;
2045 cork->base.addr = 0;
2046 cork->base.opt = NULL;
2047 v6_cork.opt = NULL;
2048 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt);
2049 if (err) {
2050 ip6_cork_release(cork, &v6_cork);
2051 return ERR_PTR(err);
2052 }
2053 if (ipc6->dontfrag < 0)
2054 ipc6->dontfrag = inet6_test_bit(DONTFRAG, sk);
2055
2056 err = __ip6_append_data(sk, &queue, cork, &v6_cork,
2057 ¤t->task_frag, getfrag, from,
2058 length + exthdrlen, transhdrlen + exthdrlen,
2059 flags, ipc6);
2060 if (err) {
2061 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
2062 return ERR_PTR(err);
2063 }
2064
2065 return __ip6_make_skb(sk, &queue, cork, &v6_cork);
2066}