1 /*
2 * IPv6 output functions
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on linux/net/ipv4/ip_output.c
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Changes:
16 * A.N.Kuznetsov : airthmetics in fragmentation.
17 * extension headers are implemented.
18 * route changes now work.
19 * ip6_forward does not confuse sniffers.
20 * etc.
21 *
22 * H. von Brand : Added missing #include <linux/string.h>
23 * Imran Patel : frag id should be in NBO
24 * Kazunori MIYAZAWA @USAGI
25 * : add ip6_append_data and related functions
26 * for datagram xmit
27 */
28
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/string.h>
32 #include <linux/socket.h>
33 #include <linux/net.h>
34 #include <linux/netdevice.h>
35 #include <linux/if_arp.h>
36 #include <linux/in6.h>
37 #include <linux/tcp.h>
38 #include <linux/route.h>
39 #include <linux/module.h>
40 #include <linux/slab.h>
41
42 #include <linux/bpf-cgroup.h>
43 #include <linux/netfilter.h>
44 #include <linux/netfilter_ipv6.h>
45
46 #include <net/sock.h>
47 #include <net/snmp.h>
48
49 #include <net/ipv6.h>
50 #include <net/ndisc.h>
51 #include <net/protocol.h>
52 #include <net/ip6_route.h>
53 #include <net/addrconf.h>
54 #include <net/rawv6.h>
55 #include <net/icmp.h>
56 #include <net/xfrm.h>
57 #include <net/checksum.h>
58 #include <linux/mroute6.h>
59 #include <net/l3mdev.h>
60 #include <net/lwtunnel.h>
61
ip6_finish_output2(struct net * net,struct sock * sk,struct sk_buff * skb)62 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
63 {
64 struct dst_entry *dst = skb_dst(skb);
65 struct net_device *dev = dst->dev;
66 struct neighbour *neigh;
67 struct in6_addr *nexthop;
68 int ret;
69
70 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
71 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
72
73 if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
74 ((mroute6_is_socket(net, skb) &&
75 !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
76 ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
77 &ipv6_hdr(skb)->saddr))) {
78 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
79
80 /* Do not check for IFF_ALLMULTI; multicast routing
81 is not supported in any case.
82 */
83 if (newskb)
84 NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
85 net, sk, newskb, NULL, newskb->dev,
86 dev_loopback_xmit);
87
88 if (ipv6_hdr(skb)->hop_limit == 0) {
89 IP6_INC_STATS(net, idev,
90 IPSTATS_MIB_OUTDISCARDS);
91 kfree_skb(skb);
92 return 0;
93 }
94 }
95
96 IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
97
98 if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
99 IPV6_ADDR_SCOPE_NODELOCAL &&
100 !(dev->flags & IFF_LOOPBACK)) {
101 kfree_skb(skb);
102 return 0;
103 }
104 }
105
106 if (lwtunnel_xmit_redirect(dst->lwtstate)) {
107 int res = lwtunnel_xmit(skb);
108
109 if (res < 0 || res == LWTUNNEL_XMIT_DONE)
110 return res;
111 }
112
113 rcu_read_lock_bh();
114 nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
115 neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
116 if (unlikely(!neigh))
117 neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
118 if (!IS_ERR(neigh)) {
119 sock_confirm_neigh(skb, neigh);
120 ret = neigh_output(neigh, skb);
121 rcu_read_unlock_bh();
122 return ret;
123 }
124 rcu_read_unlock_bh();
125
126 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
127 kfree_skb(skb);
128 return -EINVAL;
129 }
130
ip6_finish_output(struct net * net,struct sock * sk,struct sk_buff * skb)131 static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
132 {
133 int ret;
134
135 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
136 if (ret) {
137 kfree_skb(skb);
138 return ret;
139 }
140
141 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
142 /* Policy lookup after SNAT yielded a new policy */
143 if (skb_dst(skb)->xfrm) {
144 IPCB(skb)->flags |= IPSKB_REROUTED;
145 return dst_output(net, sk, skb);
146 }
147 #endif
148
149 if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
150 dst_allfrag(skb_dst(skb)) ||
151 (IP6CB(skb)->frag_max_size && skb->len > IP6CB(skb)->frag_max_size))
152 return ip6_fragment(net, sk, skb, ip6_finish_output2);
153 else
154 return ip6_finish_output2(net, sk, skb);
155 }
156
ip6_output(struct net * net,struct sock * sk,struct sk_buff * skb)157 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
158 {
159 struct net_device *dev = skb_dst(skb)->dev;
160 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
161
162 skb->protocol = htons(ETH_P_IPV6);
163 skb->dev = dev;
164
165 if (unlikely(idev->cnf.disable_ipv6)) {
166 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
167 kfree_skb(skb);
168 return 0;
169 }
170
171 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
172 net, sk, skb, NULL, dev,
173 ip6_finish_output,
174 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
175 }
176
ip6_autoflowlabel(struct net * net,const struct ipv6_pinfo * np)177 bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np)
178 {
179 if (!np->autoflowlabel_set)
180 return ip6_default_np_autolabel(net);
181 else
182 return np->autoflowlabel;
183 }
184
185 /*
186 * xmit an sk_buff (used by TCP, SCTP and DCCP)
187 * Note : socket lock is not held for SYNACK packets, but might be modified
188 * by calls to skb_set_owner_w() and ipv6_local_error(),
189 * which are using proper atomic operations or spinlocks.
190 */
ip6_xmit(const struct sock * sk,struct sk_buff * skb,struct flowi6 * fl6,__u32 mark,struct ipv6_txoptions * opt,int tclass)191 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
192 __u32 mark, struct ipv6_txoptions *opt, int tclass)
193 {
194 struct net *net = sock_net(sk);
195 const struct ipv6_pinfo *np = inet6_sk(sk);
196 struct in6_addr *first_hop = &fl6->daddr;
197 struct dst_entry *dst = skb_dst(skb);
198 struct ipv6hdr *hdr;
199 u8 proto = fl6->flowi6_proto;
200 int seg_len = skb->len;
201 int hlimit = -1;
202 u32 mtu;
203
204 if (opt) {
205 unsigned int head_room;
206
207 /* First: exthdrs may take lots of space (~8K for now)
208 MAX_HEADER is not enough.
209 */
210 head_room = opt->opt_nflen + opt->opt_flen;
211 seg_len += head_room;
212 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
213
214 if (skb_headroom(skb) < head_room) {
215 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
216 if (!skb2) {
217 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
218 IPSTATS_MIB_OUTDISCARDS);
219 kfree_skb(skb);
220 return -ENOBUFS;
221 }
222 if (skb->sk)
223 skb_set_owner_w(skb2, skb->sk);
224 consume_skb(skb);
225 skb = skb2;
226 }
227 if (opt->opt_flen)
228 ipv6_push_frag_opts(skb, opt, &proto);
229 if (opt->opt_nflen)
230 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,
231 &fl6->saddr);
232 }
233
234 skb_push(skb, sizeof(struct ipv6hdr));
235 skb_reset_network_header(skb);
236 hdr = ipv6_hdr(skb);
237
238 /*
239 * Fill in the IPv6 header
240 */
241 if (np)
242 hlimit = np->hop_limit;
243 if (hlimit < 0)
244 hlimit = ip6_dst_hoplimit(dst);
245
246 ip6_flow_hdr(hdr, tclass, ip6_make_flowlabel(net, skb, fl6->flowlabel,
247 ip6_autoflowlabel(net, np), fl6));
248
249 hdr->payload_len = htons(seg_len);
250 hdr->nexthdr = proto;
251 hdr->hop_limit = hlimit;
252
253 hdr->saddr = fl6->saddr;
254 hdr->daddr = *first_hop;
255
256 skb->protocol = htons(ETH_P_IPV6);
257 skb->priority = sk->sk_priority;
258 skb->mark = mark;
259
260 mtu = dst_mtu(dst);
261 if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
262 IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
263 IPSTATS_MIB_OUT, skb->len);
264
265 /* if egress device is enslaved to an L3 master device pass the
266 * skb to its handler for processing
267 */
268 skb = l3mdev_ip6_out((struct sock *)sk, skb);
269 if (unlikely(!skb))
270 return 0;
271
272 /* hooks should never assume socket lock is held.
273 * we promote our socket to non const
274 */
275 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
276 net, (struct sock *)sk, skb, NULL, dst->dev,
277 dst_output);
278 }
279
280 skb->dev = dst->dev;
281 /* ipv6_local_error() does not require socket lock,
282 * we promote our socket to non const
283 */
284 ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
285
286 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
287 kfree_skb(skb);
288 return -EMSGSIZE;
289 }
290 EXPORT_SYMBOL(ip6_xmit);
291
ip6_call_ra_chain(struct sk_buff * skb,int sel)292 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
293 {
294 struct ip6_ra_chain *ra;
295 struct sock *last = NULL;
296
297 read_lock(&ip6_ra_lock);
298 for (ra = ip6_ra_chain; ra; ra = ra->next) {
299 struct sock *sk = ra->sk;
300 if (sk && ra->sel == sel &&
301 (!sk->sk_bound_dev_if ||
302 sk->sk_bound_dev_if == skb->dev->ifindex)) {
303 if (last) {
304 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
305 if (skb2)
306 rawv6_rcv(last, skb2);
307 }
308 last = sk;
309 }
310 }
311
312 if (last) {
313 rawv6_rcv(last, skb);
314 read_unlock(&ip6_ra_lock);
315 return 1;
316 }
317 read_unlock(&ip6_ra_lock);
318 return 0;
319 }
320
ip6_forward_proxy_check(struct sk_buff * skb)321 static int ip6_forward_proxy_check(struct sk_buff *skb)
322 {
323 struct ipv6hdr *hdr = ipv6_hdr(skb);
324 u8 nexthdr = hdr->nexthdr;
325 __be16 frag_off;
326 int offset;
327
328 if (ipv6_ext_hdr(nexthdr)) {
329 offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr, &frag_off);
330 if (offset < 0)
331 return 0;
332 } else
333 offset = sizeof(struct ipv6hdr);
334
335 if (nexthdr == IPPROTO_ICMPV6) {
336 struct icmp6hdr *icmp6;
337
338 if (!pskb_may_pull(skb, (skb_network_header(skb) +
339 offset + 1 - skb->data)))
340 return 0;
341
342 icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
343
344 switch (icmp6->icmp6_type) {
345 case NDISC_ROUTER_SOLICITATION:
346 case NDISC_ROUTER_ADVERTISEMENT:
347 case NDISC_NEIGHBOUR_SOLICITATION:
348 case NDISC_NEIGHBOUR_ADVERTISEMENT:
349 case NDISC_REDIRECT:
350 /* For reaction involving unicast neighbor discovery
351 * message destined to the proxied address, pass it to
352 * input function.
353 */
354 return 1;
355 default:
356 break;
357 }
358 }
359
360 /*
361 * The proxying router can't forward traffic sent to a link-local
362 * address, so signal the sender and discard the packet. This
363 * behavior is clarified by the MIPv6 specification.
364 */
365 if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
366 dst_link_failure(skb);
367 return -1;
368 }
369
370 return 0;
371 }
372
ip6_forward_finish(struct net * net,struct sock * sk,struct sk_buff * skb)373 static inline int ip6_forward_finish(struct net *net, struct sock *sk,
374 struct sk_buff *skb)
375 {
376 struct dst_entry *dst = skb_dst(skb);
377
378 __IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
379 __IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
380
381 return dst_output(net, sk, skb);
382 }
383
ip6_pkt_too_big(const struct sk_buff * skb,unsigned int mtu)384 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
385 {
386 if (skb->len <= mtu)
387 return false;
388
389 /* ipv6 conntrack defrag sets max_frag_size + ignore_df */
390 if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
391 return true;
392
393 if (skb->ignore_df)
394 return false;
395
396 if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
397 return false;
398
399 return true;
400 }
401
ip6_forward(struct sk_buff * skb)402 int ip6_forward(struct sk_buff *skb)
403 {
404 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
405 struct dst_entry *dst = skb_dst(skb);
406 struct ipv6hdr *hdr = ipv6_hdr(skb);
407 struct inet6_skb_parm *opt = IP6CB(skb);
408 struct net *net = dev_net(dst->dev);
409 u32 mtu;
410
411 if (net->ipv6.devconf_all->forwarding == 0)
412 goto error;
413
414 if (skb->pkt_type != PACKET_HOST)
415 goto drop;
416
417 if (unlikely(skb->sk))
418 goto drop;
419
420 if (skb_warn_if_lro(skb))
421 goto drop;
422
423 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
424 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
425 goto drop;
426 }
427
428 skb_forward_csum(skb);
429
430 /*
431 * We DO NOT make any processing on
432 * RA packets, pushing them to user level AS IS
433 * without ane WARRANTY that application will be able
434 * to interpret them. The reason is that we
435 * cannot make anything clever here.
436 *
437 * We are not end-node, so that if packet contains
438 * AH/ESP, we cannot make anything.
439 * Defragmentation also would be mistake, RA packets
440 * cannot be fragmented, because there is no warranty
441 * that different fragments will go along one path. --ANK
442 */
443 if (unlikely(opt->flags & IP6SKB_ROUTERALERT)) {
444 if (ip6_call_ra_chain(skb, ntohs(opt->ra)))
445 return 0;
446 }
447
448 /*
449 * check and decrement ttl
450 */
451 if (hdr->hop_limit <= 1) {
452 /* Force OUTPUT device used as source address */
453 skb->dev = dst->dev;
454 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
455 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
456
457 kfree_skb(skb);
458 return -ETIMEDOUT;
459 }
460
461 /* XXX: idev->cnf.proxy_ndp? */
462 if (net->ipv6.devconf_all->proxy_ndp &&
463 pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
464 int proxied = ip6_forward_proxy_check(skb);
465 if (proxied > 0)
466 return ip6_input(skb);
467 else if (proxied < 0) {
468 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
469 goto drop;
470 }
471 }
472
473 if (!xfrm6_route_forward(skb)) {
474 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
475 goto drop;
476 }
477 dst = skb_dst(skb);
478
479 /* IPv6 specs say nothing about it, but it is clear that we cannot
480 send redirects to source routed frames.
481 We don't send redirects to frames decapsulated from IPsec.
482 */
483 if (IP6CB(skb)->iif == dst->dev->ifindex &&
484 opt->srcrt == 0 && !skb_sec_path(skb)) {
485 struct in6_addr *target = NULL;
486 struct inet_peer *peer;
487 struct rt6_info *rt;
488
489 /*
490 * incoming and outgoing devices are the same
491 * send a redirect.
492 */
493
494 rt = (struct rt6_info *) dst;
495 if (rt->rt6i_flags & RTF_GATEWAY)
496 target = &rt->rt6i_gateway;
497 else
498 target = &hdr->daddr;
499
500 peer = inet_getpeer_v6(net->ipv6.peers, &hdr->daddr, 1);
501
502 /* Limit redirects both by destination (here)
503 and by source (inside ndisc_send_redirect)
504 */
505 if (inet_peer_xrlim_allow(peer, 1*HZ))
506 ndisc_send_redirect(skb, target);
507 if (peer)
508 inet_putpeer(peer);
509 } else {
510 int addrtype = ipv6_addr_type(&hdr->saddr);
511
512 /* This check is security critical. */
513 if (addrtype == IPV6_ADDR_ANY ||
514 addrtype & (IPV6_ADDR_MULTICAST | IPV6_ADDR_LOOPBACK))
515 goto error;
516 if (addrtype & IPV6_ADDR_LINKLOCAL) {
517 icmpv6_send(skb, ICMPV6_DEST_UNREACH,
518 ICMPV6_NOT_NEIGHBOUR, 0);
519 goto error;
520 }
521 }
522
523 mtu = ip6_dst_mtu_forward(dst);
524 if (mtu < IPV6_MIN_MTU)
525 mtu = IPV6_MIN_MTU;
526
527 if (ip6_pkt_too_big(skb, mtu)) {
528 /* Again, force OUTPUT device used as source address */
529 skb->dev = dst->dev;
530 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
531 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
532 __IP6_INC_STATS(net, ip6_dst_idev(dst),
533 IPSTATS_MIB_FRAGFAILS);
534 kfree_skb(skb);
535 return -EMSGSIZE;
536 }
537
538 if (skb_cow(skb, dst->dev->hard_header_len)) {
539 __IP6_INC_STATS(net, ip6_dst_idev(dst),
540 IPSTATS_MIB_OUTDISCARDS);
541 goto drop;
542 }
543
544 hdr = ipv6_hdr(skb);
545
546 /* Mangling hops number delayed to point after skb COW */
547
548 hdr->hop_limit--;
549
550 return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
551 net, NULL, skb, skb->dev, dst->dev,
552 ip6_forward_finish);
553
554 error:
555 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
556 drop:
557 kfree_skb(skb);
558 return -EINVAL;
559 }
560
ip6_copy_metadata(struct sk_buff * to,struct sk_buff * from)561 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
562 {
563 to->pkt_type = from->pkt_type;
564 to->priority = from->priority;
565 to->protocol = from->protocol;
566 skb_dst_drop(to);
567 skb_dst_set(to, dst_clone(skb_dst(from)));
568 to->dev = from->dev;
569 to->mark = from->mark;
570
571 skb_copy_hash(to, from);
572
573 #ifdef CONFIG_NET_SCHED
574 to->tc_index = from->tc_index;
575 #endif
576 nf_copy(to, from);
577 skb_copy_secmark(to, from);
578 }
579
ip6_fragment(struct net * net,struct sock * sk,struct sk_buff * skb,int (* output)(struct net *,struct sock *,struct sk_buff *))580 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
581 int (*output)(struct net *, struct sock *, struct sk_buff *))
582 {
583 struct sk_buff *frag;
584 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
585 struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
586 inet6_sk(skb->sk) : NULL;
587 struct ipv6hdr *tmp_hdr;
588 struct frag_hdr *fh;
589 unsigned int mtu, hlen, left, len;
590 int hroom, troom;
591 __be32 frag_id;
592 int ptr, offset = 0, err = 0;
593 u8 *prevhdr, nexthdr = 0;
594
595 err = ip6_find_1stfragopt(skb, &prevhdr);
596 if (err < 0)
597 goto fail;
598 hlen = err;
599 nexthdr = *prevhdr;
600
601 mtu = ip6_skb_dst_mtu(skb);
602
603 /* We must not fragment if the socket is set to force MTU discovery
604 * or if the skb it not generated by a local socket.
605 */
606 if (unlikely(!skb->ignore_df && skb->len > mtu))
607 goto fail_toobig;
608
609 if (IP6CB(skb)->frag_max_size) {
610 if (IP6CB(skb)->frag_max_size > mtu)
611 goto fail_toobig;
612
613 /* don't send fragments larger than what we received */
614 mtu = IP6CB(skb)->frag_max_size;
615 if (mtu < IPV6_MIN_MTU)
616 mtu = IPV6_MIN_MTU;
617 }
618
619 if (np && np->frag_size < mtu) {
620 if (np->frag_size)
621 mtu = np->frag_size;
622 }
623 if (mtu < hlen + sizeof(struct frag_hdr) + 8)
624 goto fail_toobig;
625 mtu -= hlen + sizeof(struct frag_hdr);
626
627 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
628 &ipv6_hdr(skb)->saddr);
629
630 if (skb->ip_summed == CHECKSUM_PARTIAL &&
631 (err = skb_checksum_help(skb)))
632 goto fail;
633
634 hroom = LL_RESERVED_SPACE(rt->dst.dev);
635 if (skb_has_frag_list(skb)) {
636 unsigned int first_len = skb_pagelen(skb);
637 struct sk_buff *frag2;
638
639 if (first_len - hlen > mtu ||
640 ((first_len - hlen) & 7) ||
641 skb_cloned(skb) ||
642 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
643 goto slow_path;
644
645 skb_walk_frags(skb, frag) {
646 /* Correct geometry. */
647 if (frag->len > mtu ||
648 ((frag->len & 7) && frag->next) ||
649 skb_headroom(frag) < (hlen + hroom + sizeof(struct frag_hdr)))
650 goto slow_path_clean;
651
652 /* Partially cloned skb? */
653 if (skb_shared(frag))
654 goto slow_path_clean;
655
656 BUG_ON(frag->sk);
657 if (skb->sk) {
658 frag->sk = skb->sk;
659 frag->destructor = sock_wfree;
660 }
661 skb->truesize -= frag->truesize;
662 }
663
664 err = 0;
665 offset = 0;
666 /* BUILD HEADER */
667
668 *prevhdr = NEXTHDR_FRAGMENT;
669 tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
670 if (!tmp_hdr) {
671 err = -ENOMEM;
672 goto fail;
673 }
674 frag = skb_shinfo(skb)->frag_list;
675 skb_frag_list_init(skb);
676
677 __skb_pull(skb, hlen);
678 fh = __skb_push(skb, sizeof(struct frag_hdr));
679 __skb_push(skb, hlen);
680 skb_reset_network_header(skb);
681 memcpy(skb_network_header(skb), tmp_hdr, hlen);
682
683 fh->nexthdr = nexthdr;
684 fh->reserved = 0;
685 fh->frag_off = htons(IP6_MF);
686 fh->identification = frag_id;
687
688 first_len = skb_pagelen(skb);
689 skb->data_len = first_len - skb_headlen(skb);
690 skb->len = first_len;
691 ipv6_hdr(skb)->payload_len = htons(first_len -
692 sizeof(struct ipv6hdr));
693
694 for (;;) {
695 /* Prepare header of the next frame,
696 * before previous one went down. */
697 if (frag) {
698 frag->ip_summed = CHECKSUM_NONE;
699 skb_reset_transport_header(frag);
700 fh = __skb_push(frag, sizeof(struct frag_hdr));
701 __skb_push(frag, hlen);
702 skb_reset_network_header(frag);
703 memcpy(skb_network_header(frag), tmp_hdr,
704 hlen);
705 offset += skb->len - hlen - sizeof(struct frag_hdr);
706 fh->nexthdr = nexthdr;
707 fh->reserved = 0;
708 fh->frag_off = htons(offset);
709 if (frag->next)
710 fh->frag_off |= htons(IP6_MF);
711 fh->identification = frag_id;
712 ipv6_hdr(frag)->payload_len =
713 htons(frag->len -
714 sizeof(struct ipv6hdr));
715 ip6_copy_metadata(frag, skb);
716 }
717
718 err = output(net, sk, skb);
719 if (!err)
720 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
721 IPSTATS_MIB_FRAGCREATES);
722
723 if (err || !frag)
724 break;
725
726 skb = frag;
727 frag = skb->next;
728 skb->next = NULL;
729 }
730
731 kfree(tmp_hdr);
732
733 if (err == 0) {
734 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
735 IPSTATS_MIB_FRAGOKS);
736 return 0;
737 }
738
739 kfree_skb_list(frag);
740
741 IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
742 IPSTATS_MIB_FRAGFAILS);
743 return err;
744
745 slow_path_clean:
746 skb_walk_frags(skb, frag2) {
747 if (frag2 == frag)
748 break;
749 frag2->sk = NULL;
750 frag2->destructor = NULL;
751 skb->truesize += frag2->truesize;
752 }
753 }
754
755 slow_path:
756 left = skb->len - hlen; /* Space per frame */
757 ptr = hlen; /* Where to start from */
758
759 /*
760 * Fragment the datagram.
761 */
762
763 troom = rt->dst.dev->needed_tailroom;
764
765 /*
766 * Keep copying data until we run out.
767 */
768 while (left > 0) {
769 u8 *fragnexthdr_offset;
770
771 len = left;
772 /* IF: it doesn't fit, use 'mtu' - the data space left */
773 if (len > mtu)
774 len = mtu;
775 /* IF: we are not sending up to and including the packet end
776 then align the next start on an eight byte boundary */
777 if (len < left) {
778 len &= ~7;
779 }
780
781 /* Allocate buffer */
782 frag = alloc_skb(len + hlen + sizeof(struct frag_hdr) +
783 hroom + troom, GFP_ATOMIC);
784 if (!frag) {
785 err = -ENOMEM;
786 goto fail;
787 }
788
789 /*
790 * Set up data on packet
791 */
792
793 ip6_copy_metadata(frag, skb);
794 skb_reserve(frag, hroom);
795 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
796 skb_reset_network_header(frag);
797 fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
798 frag->transport_header = (frag->network_header + hlen +
799 sizeof(struct frag_hdr));
800
801 /*
802 * Charge the memory for the fragment to any owner
803 * it might possess
804 */
805 if (skb->sk)
806 skb_set_owner_w(frag, skb->sk);
807
808 /*
809 * Copy the packet header into the new buffer.
810 */
811 skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);
812
813 fragnexthdr_offset = skb_network_header(frag);
814 fragnexthdr_offset += prevhdr - skb_network_header(skb);
815 *fragnexthdr_offset = NEXTHDR_FRAGMENT;
816
817 /*
818 * Build fragment header.
819 */
820 fh->nexthdr = nexthdr;
821 fh->reserved = 0;
822 fh->identification = frag_id;
823
824 /*
825 * Copy a block of the IP datagram.
826 */
827 BUG_ON(skb_copy_bits(skb, ptr, skb_transport_header(frag),
828 len));
829 left -= len;
830
831 fh->frag_off = htons(offset);
832 if (left > 0)
833 fh->frag_off |= htons(IP6_MF);
834 ipv6_hdr(frag)->payload_len = htons(frag->len -
835 sizeof(struct ipv6hdr));
836
837 ptr += len;
838 offset += len;
839
840 /*
841 * Put this fragment into the sending queue.
842 */
843 err = output(net, sk, frag);
844 if (err)
845 goto fail;
846
847 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
848 IPSTATS_MIB_FRAGCREATES);
849 }
850 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
851 IPSTATS_MIB_FRAGOKS);
852 consume_skb(skb);
853 return err;
854
855 fail_toobig:
856 if (skb->sk && dst_allfrag(skb_dst(skb)))
857 sk_nocaps_add(skb->sk, NETIF_F_GSO_MASK);
858
859 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
860 err = -EMSGSIZE;
861
862 fail:
863 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
864 IPSTATS_MIB_FRAGFAILS);
865 kfree_skb(skb);
866 return err;
867 }
868
ip6_rt_check(const struct rt6key * rt_key,const struct in6_addr * fl_addr,const struct in6_addr * addr_cache)869 static inline int ip6_rt_check(const struct rt6key *rt_key,
870 const struct in6_addr *fl_addr,
871 const struct in6_addr *addr_cache)
872 {
873 return (rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
874 (!addr_cache || !ipv6_addr_equal(fl_addr, addr_cache));
875 }
876
ip6_sk_dst_check(struct sock * sk,struct dst_entry * dst,const struct flowi6 * fl6)877 static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
878 struct dst_entry *dst,
879 const struct flowi6 *fl6)
880 {
881 struct ipv6_pinfo *np = inet6_sk(sk);
882 struct rt6_info *rt;
883
884 if (!dst)
885 goto out;
886
887 if (dst->ops->family != AF_INET6) {
888 dst_release(dst);
889 return NULL;
890 }
891
892 rt = (struct rt6_info *)dst;
893 /* Yes, checking route validity in not connected
894 * case is not very simple. Take into account,
895 * that we do not support routing by source, TOS,
896 * and MSG_DONTROUTE --ANK (980726)
897 *
898 * 1. ip6_rt_check(): If route was host route,
899 * check that cached destination is current.
900 * If it is network route, we still may
901 * check its validity using saved pointer
902 * to the last used address: daddr_cache.
903 * We do not want to save whole address now,
904 * (because main consumer of this service
905 * is tcp, which has not this problem),
906 * so that the last trick works only on connected
907 * sockets.
908 * 2. oif also should be the same.
909 */
910 if (ip6_rt_check(&rt->rt6i_dst, &fl6->daddr, np->daddr_cache) ||
911 #ifdef CONFIG_IPV6_SUBTREES
912 ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
913 #endif
914 (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
915 (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
916 dst_release(dst);
917 dst = NULL;
918 }
919
920 out:
921 return dst;
922 }
923
ip6_dst_lookup_tail(struct net * net,const struct sock * sk,struct dst_entry ** dst,struct flowi6 * fl6)924 static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
925 struct dst_entry **dst, struct flowi6 *fl6)
926 {
927 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
928 struct neighbour *n;
929 struct rt6_info *rt;
930 #endif
931 int err;
932 int flags = 0;
933
934 /* The correct way to handle this would be to do
935 * ip6_route_get_saddr, and then ip6_route_output; however,
936 * the route-specific preferred source forces the
937 * ip6_route_output call _before_ ip6_route_get_saddr.
938 *
939 * In source specific routing (no src=any default route),
940 * ip6_route_output will fail given src=any saddr, though, so
941 * that's why we try it again later.
942 */
943 if (ipv6_addr_any(&fl6->saddr) && (!*dst || !(*dst)->error)) {
944 struct fib6_info *from;
945 struct rt6_info *rt;
946 bool had_dst = *dst != NULL;
947
948 if (!had_dst)
949 *dst = ip6_route_output(net, sk, fl6);
950 rt = (*dst)->error ? NULL : (struct rt6_info *)*dst;
951
952 rcu_read_lock();
953 from = rt ? rcu_dereference(rt->from) : NULL;
954 err = ip6_route_get_saddr(net, from, &fl6->daddr,
955 sk ? inet6_sk(sk)->srcprefs : 0,
956 &fl6->saddr);
957 rcu_read_unlock();
958
959 if (err)
960 goto out_err_release;
961
962 /* If we had an erroneous initial result, pretend it
963 * never existed and let the SA-enabled version take
964 * over.
965 */
966 if (!had_dst && (*dst)->error) {
967 dst_release(*dst);
968 *dst = NULL;
969 }
970
971 if (fl6->flowi6_oif)
972 flags |= RT6_LOOKUP_F_IFACE;
973 }
974
975 if (!*dst)
976 *dst = ip6_route_output_flags(net, sk, fl6, flags);
977
978 err = (*dst)->error;
979 if (err)
980 goto out_err_release;
981
982 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
983 /*
984 * Here if the dst entry we've looked up
985 * has a neighbour entry that is in the INCOMPLETE
986 * state and the src address from the flow is
987 * marked as OPTIMISTIC, we release the found
988 * dst entry and replace it instead with the
989 * dst entry of the nexthop router
990 */
991 rt = (struct rt6_info *) *dst;
992 rcu_read_lock_bh();
993 n = __ipv6_neigh_lookup_noref(rt->dst.dev,
994 rt6_nexthop(rt, &fl6->daddr));
995 err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0;
996 rcu_read_unlock_bh();
997
998 if (err) {
999 struct inet6_ifaddr *ifp;
1000 struct flowi6 fl_gw6;
1001 int redirect;
1002
1003 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
1004 (*dst)->dev, 1);
1005
1006 redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
1007 if (ifp)
1008 in6_ifa_put(ifp);
1009
1010 if (redirect) {
1011 /*
1012 * We need to get the dst entry for the
1013 * default router instead
1014 */
1015 dst_release(*dst);
1016 memcpy(&fl_gw6, fl6, sizeof(struct flowi6));
1017 memset(&fl_gw6.daddr, 0, sizeof(struct in6_addr));
1018 *dst = ip6_route_output(net, sk, &fl_gw6);
1019 err = (*dst)->error;
1020 if (err)
1021 goto out_err_release;
1022 }
1023 }
1024 #endif
1025 if (ipv6_addr_v4mapped(&fl6->saddr) &&
1026 !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr))) {
1027 err = -EAFNOSUPPORT;
1028 goto out_err_release;
1029 }
1030
1031 return 0;
1032
1033 out_err_release:
1034 dst_release(*dst);
1035 *dst = NULL;
1036
1037 if (err == -ENETUNREACH)
1038 IP6_INC_STATS(net, NULL, IPSTATS_MIB_OUTNOROUTES);
1039 return err;
1040 }
1041
1042 /**
1043 * ip6_dst_lookup - perform route lookup on flow
1044 * @sk: socket which provides route info
1045 * @dst: pointer to dst_entry * for result
1046 * @fl6: flow to lookup
1047 *
1048 * This function performs a route lookup on the given flow.
1049 *
1050 * It returns zero on success, or a standard errno code on error.
1051 */
ip6_dst_lookup(struct net * net,struct sock * sk,struct dst_entry ** dst,struct flowi6 * fl6)1052 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
1053 struct flowi6 *fl6)
1054 {
1055 *dst = NULL;
1056 return ip6_dst_lookup_tail(net, sk, dst, fl6);
1057 }
1058 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
1059
1060 /**
1061 * ip6_dst_lookup_flow - perform route lookup on flow with ipsec
1062 * @sk: socket which provides route info
1063 * @fl6: flow to lookup
1064 * @final_dst: final destination address for ipsec lookup
1065 *
1066 * This function performs a route lookup on the given flow.
1067 *
1068 * It returns a valid dst pointer on success, or a pointer encoded
1069 * error code.
1070 */
ip6_dst_lookup_flow(const struct sock * sk,struct flowi6 * fl6,const struct in6_addr * final_dst)1071 struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
1072 const struct in6_addr *final_dst)
1073 {
1074 struct dst_entry *dst = NULL;
1075 int err;
1076
1077 err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
1078 if (err)
1079 return ERR_PTR(err);
1080 if (final_dst)
1081 fl6->daddr = *final_dst;
1082
1083 return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
1084 }
1085 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
1086
1087 /**
1088 * ip6_sk_dst_lookup_flow - perform socket cached route lookup on flow
1089 * @sk: socket which provides the dst cache and route info
1090 * @fl6: flow to lookup
1091 * @final_dst: final destination address for ipsec lookup
1092 * @connected: whether @sk is connected or not
1093 *
1094 * This function performs a route lookup on the given flow with the
1095 * possibility of using the cached route in the socket if it is valid.
1096 * It will take the socket dst lock when operating on the dst cache.
1097 * As a result, this function can only be used in process context.
1098 *
1099 * In addition, for a connected socket, cache the dst in the socket
1100 * if the current cache is not valid.
1101 *
1102 * It returns a valid dst pointer on success, or a pointer encoded
1103 * error code.
1104 */
ip6_sk_dst_lookup_flow(struct sock * sk,struct flowi6 * fl6,const struct in6_addr * final_dst,bool connected)1105 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
1106 const struct in6_addr *final_dst,
1107 bool connected)
1108 {
1109 struct dst_entry *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
1110
1111 dst = ip6_sk_dst_check(sk, dst, fl6);
1112 if (dst)
1113 return dst;
1114
1115 dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
1116 if (connected && !IS_ERR(dst))
1117 ip6_sk_dst_store_flow(sk, dst_clone(dst), fl6);
1118
1119 return dst;
1120 }
1121 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1122
ip6_opt_dup(struct ipv6_opt_hdr * src,gfp_t gfp)1123 static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
1124 gfp_t gfp)
1125 {
1126 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1127 }
1128
ip6_rthdr_dup(struct ipv6_rt_hdr * src,gfp_t gfp)1129 static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
1130 gfp_t gfp)
1131 {
1132 return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
1133 }
1134
ip6_append_data_mtu(unsigned int * mtu,int * maxfraglen,unsigned int fragheaderlen,struct sk_buff * skb,struct rt6_info * rt,unsigned int orig_mtu)1135 static void ip6_append_data_mtu(unsigned int *mtu,
1136 int *maxfraglen,
1137 unsigned int fragheaderlen,
1138 struct sk_buff *skb,
1139 struct rt6_info *rt,
1140 unsigned int orig_mtu)
1141 {
1142 if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
1143 if (!skb) {
1144 /* first fragment, reserve header_len */
1145 *mtu = orig_mtu - rt->dst.header_len;
1146
1147 } else {
1148 /*
1149 * this fragment is not first, the headers
1150 * space is regarded as data space.
1151 */
1152 *mtu = orig_mtu;
1153 }
1154 *maxfraglen = ((*mtu - fragheaderlen) & ~7)
1155 + fragheaderlen - sizeof(struct frag_hdr);
1156 }
1157 }
1158
ip6_setup_cork(struct sock * sk,struct inet_cork_full * cork,struct inet6_cork * v6_cork,struct ipcm6_cookie * ipc6,struct rt6_info * rt,struct flowi6 * fl6)1159 static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
1160 struct inet6_cork *v6_cork, struct ipcm6_cookie *ipc6,
1161 struct rt6_info *rt, struct flowi6 *fl6)
1162 {
1163 struct ipv6_pinfo *np = inet6_sk(sk);
1164 unsigned int mtu;
1165 struct ipv6_txoptions *opt = ipc6->opt;
1166
1167 /*
1168 * setup for corking
1169 */
1170 if (opt) {
1171 if (WARN_ON(v6_cork->opt))
1172 return -EINVAL;
1173
1174 v6_cork->opt = kzalloc(sizeof(*opt), sk->sk_allocation);
1175 if (unlikely(!v6_cork->opt))
1176 return -ENOBUFS;
1177
1178 v6_cork->opt->tot_len = sizeof(*opt);
1179 v6_cork->opt->opt_flen = opt->opt_flen;
1180 v6_cork->opt->opt_nflen = opt->opt_nflen;
1181
1182 v6_cork->opt->dst0opt = ip6_opt_dup(opt->dst0opt,
1183 sk->sk_allocation);
1184 if (opt->dst0opt && !v6_cork->opt->dst0opt)
1185 return -ENOBUFS;
1186
1187 v6_cork->opt->dst1opt = ip6_opt_dup(opt->dst1opt,
1188 sk->sk_allocation);
1189 if (opt->dst1opt && !v6_cork->opt->dst1opt)
1190 return -ENOBUFS;
1191
1192 v6_cork->opt->hopopt = ip6_opt_dup(opt->hopopt,
1193 sk->sk_allocation);
1194 if (opt->hopopt && !v6_cork->opt->hopopt)
1195 return -ENOBUFS;
1196
1197 v6_cork->opt->srcrt = ip6_rthdr_dup(opt->srcrt,
1198 sk->sk_allocation);
1199 if (opt->srcrt && !v6_cork->opt->srcrt)
1200 return -ENOBUFS;
1201
1202 /* need source address above miyazawa*/
1203 }
1204 dst_hold(&rt->dst);
1205 cork->base.dst = &rt->dst;
1206 cork->fl.u.ip6 = *fl6;
1207 v6_cork->hop_limit = ipc6->hlimit;
1208 v6_cork->tclass = ipc6->tclass;
1209 if (rt->dst.flags & DST_XFRM_TUNNEL)
1210 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1211 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
1212 else
1213 mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ?
1214 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
1215 if (np->frag_size < mtu) {
1216 if (np->frag_size)
1217 mtu = np->frag_size;
1218 }
1219 if (mtu < IPV6_MIN_MTU)
1220 return -EINVAL;
1221 cork->base.fragsize = mtu;
1222 cork->base.gso_size = ipc6->gso_size;
1223 cork->base.tx_flags = 0;
1224 sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags);
1225
1226 if (dst_allfrag(xfrm_dst_path(&rt->dst)))
1227 cork->base.flags |= IPCORK_ALLFRAG;
1228 cork->base.length = 0;
1229
1230 cork->base.transmit_time = ipc6->sockc.transmit_time;
1231
1232 return 0;
1233 }
1234
__ip6_append_data(struct sock * sk,struct flowi6 * fl6,struct sk_buff_head * queue,struct inet_cork * cork,struct inet6_cork * v6_cork,struct page_frag * pfrag,int getfrag (void * from,char * to,int offset,int len,int odd,struct sk_buff * skb),void * from,int length,int transhdrlen,unsigned int flags,struct ipcm6_cookie * ipc6)1235 static int __ip6_append_data(struct sock *sk,
1236 struct flowi6 *fl6,
1237 struct sk_buff_head *queue,
1238 struct inet_cork *cork,
1239 struct inet6_cork *v6_cork,
1240 struct page_frag *pfrag,
1241 int getfrag(void *from, char *to, int offset,
1242 int len, int odd, struct sk_buff *skb),
1243 void *from, int length, int transhdrlen,
1244 unsigned int flags, struct ipcm6_cookie *ipc6)
1245 {
1246 struct sk_buff *skb, *skb_prev = NULL;
1247 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
1248 int exthdrlen = 0;
1249 int dst_exthdrlen = 0;
1250 int hh_len;
1251 int copy;
1252 int err;
1253 int offset = 0;
1254 u32 tskey = 0;
1255 struct rt6_info *rt = (struct rt6_info *)cork->dst;
1256 struct ipv6_txoptions *opt = v6_cork->opt;
1257 int csummode = CHECKSUM_NONE;
1258 unsigned int maxnonfragsize, headersize;
1259 unsigned int wmem_alloc_delta = 0;
1260 bool paged;
1261
1262 skb = skb_peek_tail(queue);
1263 if (!skb) {
1264 exthdrlen = opt ? opt->opt_flen : 0;
1265 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1266 }
1267
1268 paged = !!cork->gso_size;
1269 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
1270 orig_mtu = mtu;
1271
1272 if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
1273 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
1274 tskey = sk->sk_tskey++;
1275
1276 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1277
1278 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1279 (opt ? opt->opt_nflen : 0);
1280 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1281 sizeof(struct frag_hdr);
1282
1283 headersize = sizeof(struct ipv6hdr) +
1284 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1285 (dst_allfrag(&rt->dst) ?
1286 sizeof(struct frag_hdr) : 0) +
1287 rt->rt6i_nfheader_len;
1288
1289 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit
1290 * the first fragment
1291 */
1292 if (headersize + transhdrlen > mtu)
1293 goto emsgsize;
1294
1295 if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1296 (sk->sk_protocol == IPPROTO_UDP ||
1297 sk->sk_protocol == IPPROTO_RAW)) {
1298 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1299 sizeof(struct ipv6hdr));
1300 goto emsgsize;
1301 }
1302
1303 if (ip6_sk_ignore_df(sk))
1304 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1305 else
1306 maxnonfragsize = mtu;
1307
1308 if (cork->length + length > maxnonfragsize - headersize) {
1309 emsgsize:
1310 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
1311 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu);
1312 return -EMSGSIZE;
1313 }
1314
1315 /* CHECKSUM_PARTIAL only with no extension headers and when
1316 * we are not going to fragment
1317 */
1318 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1319 headersize == sizeof(struct ipv6hdr) &&
1320 length <= mtu - headersize &&
1321 (!(flags & MSG_MORE) || cork->gso_size) &&
1322 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1323 csummode = CHECKSUM_PARTIAL;
1324
1325 /*
1326 * Let's try using as much space as possible.
1327 * Use MTU if total length of the message fits into the MTU.
1328 * Otherwise, we need to reserve fragment header and
1329 * fragment alignment (= 8-15 octects, in total).
1330 *
1331 * Note that we may need to "move" the data from the tail of
1332 * of the buffer to the new fragment when we split
1333 * the message.
1334 *
1335 * FIXME: It may be fragmented into multiple chunks
1336 * at once if non-fragmentable extension headers
1337 * are too large.
1338 * --yoshfuji
1339 */
1340
1341 cork->length += length;
1342 if (!skb)
1343 goto alloc_new_skb;
1344
1345 while (length > 0) {
1346 /* Check if the remaining data fits into current packet. */
1347 copy = (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
1348 if (copy < length)
1349 copy = maxfraglen - skb->len;
1350
1351 if (copy <= 0) {
1352 char *data;
1353 unsigned int datalen;
1354 unsigned int fraglen;
1355 unsigned int fraggap;
1356 unsigned int alloclen;
1357 unsigned int pagedlen = 0;
1358 alloc_new_skb:
1359 /* There's no room in the current skb */
1360 if (skb)
1361 fraggap = skb->len - maxfraglen;
1362 else
1363 fraggap = 0;
1364 /* update mtu and maxfraglen if necessary */
1365 if (!skb || !skb_prev)
1366 ip6_append_data_mtu(&mtu, &maxfraglen,
1367 fragheaderlen, skb, rt,
1368 orig_mtu);
1369
1370 skb_prev = skb;
1371
1372 /*
1373 * If remaining data exceeds the mtu,
1374 * we know we need more fragment(s).
1375 */
1376 datalen = length + fraggap;
1377
1378 if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
1379 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1380 fraglen = datalen + fragheaderlen;
1381
1382 if ((flags & MSG_MORE) &&
1383 !(rt->dst.dev->features&NETIF_F_SG))
1384 alloclen = mtu;
1385 else if (!paged)
1386 alloclen = fraglen;
1387 else {
1388 alloclen = min_t(int, fraglen, MAX_HEADER);
1389 pagedlen = fraglen - alloclen;
1390 }
1391
1392 alloclen += dst_exthdrlen;
1393
1394 if (datalen != length + fraggap) {
1395 /*
1396 * this is not the last fragment, the trailer
1397 * space is regarded as data space.
1398 */
1399 datalen += rt->dst.trailer_len;
1400 }
1401
1402 alloclen += rt->dst.trailer_len;
1403 fraglen = datalen + fragheaderlen;
1404
1405 /*
1406 * We just reserve space for fragment header.
1407 * Note: this may be overallocation if the message
1408 * (without MSG_MORE) fits into the MTU.
1409 */
1410 alloclen += sizeof(struct frag_hdr);
1411
1412 copy = datalen - transhdrlen - fraggap - pagedlen;
1413 if (copy < 0) {
1414 err = -EINVAL;
1415 goto error;
1416 }
1417 if (transhdrlen) {
1418 skb = sock_alloc_send_skb(sk,
1419 alloclen + hh_len,
1420 (flags & MSG_DONTWAIT), &err);
1421 } else {
1422 skb = NULL;
1423 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
1424 2 * sk->sk_sndbuf)
1425 skb = alloc_skb(alloclen + hh_len,
1426 sk->sk_allocation);
1427 if (unlikely(!skb))
1428 err = -ENOBUFS;
1429 }
1430 if (!skb)
1431 goto error;
1432 /*
1433 * Fill in the control structures
1434 */
1435 skb->protocol = htons(ETH_P_IPV6);
1436 skb->ip_summed = csummode;
1437 skb->csum = 0;
1438 /* reserve for fragmentation and ipsec header */
1439 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1440 dst_exthdrlen);
1441
1442 /* Only the initial fragment is time stamped */
1443 skb_shinfo(skb)->tx_flags = cork->tx_flags;
1444 cork->tx_flags = 0;
1445 skb_shinfo(skb)->tskey = tskey;
1446 tskey = 0;
1447
1448 /*
1449 * Find where to start putting bytes
1450 */
1451 data = skb_put(skb, fraglen - pagedlen);
1452 skb_set_network_header(skb, exthdrlen);
1453 data += fragheaderlen;
1454 skb->transport_header = (skb->network_header +
1455 fragheaderlen);
1456 if (fraggap) {
1457 skb->csum = skb_copy_and_csum_bits(
1458 skb_prev, maxfraglen,
1459 data + transhdrlen, fraggap, 0);
1460 skb_prev->csum = csum_sub(skb_prev->csum,
1461 skb->csum);
1462 data += fraggap;
1463 pskb_trim_unique(skb_prev, maxfraglen);
1464 }
1465 if (copy > 0 &&
1466 getfrag(from, data + transhdrlen, offset,
1467 copy, fraggap, skb) < 0) {
1468 err = -EFAULT;
1469 kfree_skb(skb);
1470 goto error;
1471 }
1472
1473 offset += copy;
1474 length -= copy + transhdrlen;
1475 transhdrlen = 0;
1476 exthdrlen = 0;
1477 dst_exthdrlen = 0;
1478
1479 if ((flags & MSG_CONFIRM) && !skb_prev)
1480 skb_set_dst_pending_confirm(skb, 1);
1481
1482 /*
1483 * Put the packet on the pending queue
1484 */
1485 if (!skb->destructor) {
1486 skb->destructor = sock_wfree;
1487 skb->sk = sk;
1488 wmem_alloc_delta += skb->truesize;
1489 }
1490 __skb_queue_tail(queue, skb);
1491 continue;
1492 }
1493
1494 if (copy > length)
1495 copy = length;
1496
1497 if (!(rt->dst.dev->features&NETIF_F_SG) &&
1498 skb_tailroom(skb) >= copy) {
1499 unsigned int off;
1500
1501 off = skb->len;
1502 if (getfrag(from, skb_put(skb, copy),
1503 offset, copy, off, skb) < 0) {
1504 __skb_trim(skb, off);
1505 err = -EFAULT;
1506 goto error;
1507 }
1508 } else {
1509 int i = skb_shinfo(skb)->nr_frags;
1510
1511 err = -ENOMEM;
1512 if (!sk_page_frag_refill(sk, pfrag))
1513 goto error;
1514
1515 if (!skb_can_coalesce(skb, i, pfrag->page,
1516 pfrag->offset)) {
1517 err = -EMSGSIZE;
1518 if (i == MAX_SKB_FRAGS)
1519 goto error;
1520
1521 __skb_fill_page_desc(skb, i, pfrag->page,
1522 pfrag->offset, 0);
1523 skb_shinfo(skb)->nr_frags = ++i;
1524 get_page(pfrag->page);
1525 }
1526 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1527 if (getfrag(from,
1528 page_address(pfrag->page) + pfrag->offset,
1529 offset, copy, skb->len, skb) < 0)
1530 goto error_efault;
1531
1532 pfrag->offset += copy;
1533 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1534 skb->len += copy;
1535 skb->data_len += copy;
1536 skb->truesize += copy;
1537 wmem_alloc_delta += copy;
1538 }
1539 offset += copy;
1540 length -= copy;
1541 }
1542
1543 if (wmem_alloc_delta)
1544 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1545 return 0;
1546
1547 error_efault:
1548 err = -EFAULT;
1549 error:
1550 cork->length -= length;
1551 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1552 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1553 return err;
1554 }
1555
ip6_append_data(struct sock * sk,int getfrag (void * from,char * to,int offset,int len,int odd,struct sk_buff * skb),void * from,int length,int transhdrlen,struct ipcm6_cookie * ipc6,struct flowi6 * fl6,struct rt6_info * rt,unsigned int flags)1556 int ip6_append_data(struct sock *sk,
1557 int getfrag(void *from, char *to, int offset, int len,
1558 int odd, struct sk_buff *skb),
1559 void *from, int length, int transhdrlen,
1560 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1561 struct rt6_info *rt, unsigned int flags)
1562 {
1563 struct inet_sock *inet = inet_sk(sk);
1564 struct ipv6_pinfo *np = inet6_sk(sk);
1565 int exthdrlen;
1566 int err;
1567
1568 if (flags&MSG_PROBE)
1569 return 0;
1570 if (skb_queue_empty(&sk->sk_write_queue)) {
1571 /*
1572 * setup for corking
1573 */
1574 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1575 ipc6, rt, fl6);
1576 if (err)
1577 return err;
1578
1579 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1580 length += exthdrlen;
1581 transhdrlen += exthdrlen;
1582 } else {
1583 fl6 = &inet->cork.fl.u.ip6;
1584 transhdrlen = 0;
1585 }
1586
1587 return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base,
1588 &np->cork, sk_page_frag(sk), getfrag,
1589 from, length, transhdrlen, flags, ipc6);
1590 }
1591 EXPORT_SYMBOL_GPL(ip6_append_data);
1592
ip6_cork_release(struct inet_cork_full * cork,struct inet6_cork * v6_cork)1593 static void ip6_cork_release(struct inet_cork_full *cork,
1594 struct inet6_cork *v6_cork)
1595 {
1596 if (v6_cork->opt) {
1597 kfree(v6_cork->opt->dst0opt);
1598 kfree(v6_cork->opt->dst1opt);
1599 kfree(v6_cork->opt->hopopt);
1600 kfree(v6_cork->opt->srcrt);
1601 kfree(v6_cork->opt);
1602 v6_cork->opt = NULL;
1603 }
1604
1605 if (cork->base.dst) {
1606 dst_release(cork->base.dst);
1607 cork->base.dst = NULL;
1608 cork->base.flags &= ~IPCORK_ALLFRAG;
1609 }
1610 memset(&cork->fl, 0, sizeof(cork->fl));
1611 }
1612
__ip6_make_skb(struct sock * sk,struct sk_buff_head * queue,struct inet_cork_full * cork,struct inet6_cork * v6_cork)1613 struct sk_buff *__ip6_make_skb(struct sock *sk,
1614 struct sk_buff_head *queue,
1615 struct inet_cork_full *cork,
1616 struct inet6_cork *v6_cork)
1617 {
1618 struct sk_buff *skb, *tmp_skb;
1619 struct sk_buff **tail_skb;
1620 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1621 struct ipv6_pinfo *np = inet6_sk(sk);
1622 struct net *net = sock_net(sk);
1623 struct ipv6hdr *hdr;
1624 struct ipv6_txoptions *opt = v6_cork->opt;
1625 struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
1626 struct flowi6 *fl6 = &cork->fl.u.ip6;
1627 unsigned char proto = fl6->flowi6_proto;
1628
1629 skb = __skb_dequeue(queue);
1630 if (!skb)
1631 goto out;
1632 tail_skb = &(skb_shinfo(skb)->frag_list);
1633
1634 /* move skb->data to ip header from ext header */
1635 if (skb->data < skb_network_header(skb))
1636 __skb_pull(skb, skb_network_offset(skb));
1637 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1638 __skb_pull(tmp_skb, skb_network_header_len(skb));
1639 *tail_skb = tmp_skb;
1640 tail_skb = &(tmp_skb->next);
1641 skb->len += tmp_skb->len;
1642 skb->data_len += tmp_skb->len;
1643 skb->truesize += tmp_skb->truesize;
1644 tmp_skb->destructor = NULL;
1645 tmp_skb->sk = NULL;
1646 }
1647
1648 /* Allow local fragmentation. */
1649 skb->ignore_df = ip6_sk_ignore_df(sk);
1650
1651 *final_dst = fl6->daddr;
1652 __skb_pull(skb, skb_network_header_len(skb));
1653 if (opt && opt->opt_flen)
1654 ipv6_push_frag_opts(skb, opt, &proto);
1655 if (opt && opt->opt_nflen)
1656 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1657
1658 skb_push(skb, sizeof(struct ipv6hdr));
1659 skb_reset_network_header(skb);
1660 hdr = ipv6_hdr(skb);
1661
1662 ip6_flow_hdr(hdr, v6_cork->tclass,
1663 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1664 ip6_autoflowlabel(net, np), fl6));
1665 hdr->hop_limit = v6_cork->hop_limit;
1666 hdr->nexthdr = proto;
1667 hdr->saddr = fl6->saddr;
1668 hdr->daddr = *final_dst;
1669
1670 skb->priority = sk->sk_priority;
1671 skb->mark = sk->sk_mark;
1672
1673 skb->tstamp = cork->base.transmit_time;
1674
1675 skb_dst_set(skb, dst_clone(&rt->dst));
1676 IP6_UPD_PO_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUT, skb->len);
1677 if (proto == IPPROTO_ICMPV6) {
1678 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1679
1680 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_hdr(skb)->icmp6_type);
1681 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1682 }
1683
1684 ip6_cork_release(cork, v6_cork);
1685 out:
1686 return skb;
1687 }
1688
ip6_send_skb(struct sk_buff * skb)1689 int ip6_send_skb(struct sk_buff *skb)
1690 {
1691 struct net *net = sock_net(skb->sk);
1692 struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
1693 int err;
1694
1695 err = ip6_local_out(net, skb->sk, skb);
1696 if (err) {
1697 if (err > 0)
1698 err = net_xmit_errno(err);
1699 if (err)
1700 IP6_INC_STATS(net, rt->rt6i_idev,
1701 IPSTATS_MIB_OUTDISCARDS);
1702 }
1703
1704 return err;
1705 }
1706
ip6_push_pending_frames(struct sock * sk)1707 int ip6_push_pending_frames(struct sock *sk)
1708 {
1709 struct sk_buff *skb;
1710
1711 skb = ip6_finish_skb(sk);
1712 if (!skb)
1713 return 0;
1714
1715 return ip6_send_skb(skb);
1716 }
1717 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
1718
__ip6_flush_pending_frames(struct sock * sk,struct sk_buff_head * queue,struct inet_cork_full * cork,struct inet6_cork * v6_cork)1719 static void __ip6_flush_pending_frames(struct sock *sk,
1720 struct sk_buff_head *queue,
1721 struct inet_cork_full *cork,
1722 struct inet6_cork *v6_cork)
1723 {
1724 struct sk_buff *skb;
1725
1726 while ((skb = __skb_dequeue_tail(queue)) != NULL) {
1727 if (skb_dst(skb))
1728 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
1729 IPSTATS_MIB_OUTDISCARDS);
1730 kfree_skb(skb);
1731 }
1732
1733 ip6_cork_release(cork, v6_cork);
1734 }
1735
ip6_flush_pending_frames(struct sock * sk)1736 void ip6_flush_pending_frames(struct sock *sk)
1737 {
1738 __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
1739 &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
1740 }
1741 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
1742
ip6_make_skb(struct sock * sk,int getfrag (void * from,char * to,int offset,int len,int odd,struct sk_buff * skb),void * from,int length,int transhdrlen,struct ipcm6_cookie * ipc6,struct flowi6 * fl6,struct rt6_info * rt,unsigned int flags,struct inet_cork_full * cork)1743 struct sk_buff *ip6_make_skb(struct sock *sk,
1744 int getfrag(void *from, char *to, int offset,
1745 int len, int odd, struct sk_buff *skb),
1746 void *from, int length, int transhdrlen,
1747 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1748 struct rt6_info *rt, unsigned int flags,
1749 struct inet_cork_full *cork)
1750 {
1751 struct inet6_cork v6_cork;
1752 struct sk_buff_head queue;
1753 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1754 int err;
1755
1756 if (flags & MSG_PROBE)
1757 return NULL;
1758
1759 __skb_queue_head_init(&queue);
1760
1761 cork->base.flags = 0;
1762 cork->base.addr = 0;
1763 cork->base.opt = NULL;
1764 cork->base.dst = NULL;
1765 v6_cork.opt = NULL;
1766 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6);
1767 if (err) {
1768 ip6_cork_release(cork, &v6_cork);
1769 return ERR_PTR(err);
1770 }
1771 if (ipc6->dontfrag < 0)
1772 ipc6->dontfrag = inet6_sk(sk)->dontfrag;
1773
1774 err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork,
1775 ¤t->task_frag, getfrag, from,
1776 length + exthdrlen, transhdrlen + exthdrlen,
1777 flags, ipc6);
1778 if (err) {
1779 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
1780 return ERR_PTR(err);
1781 }
1782
1783 return __ip6_make_skb(sk, &queue, cork, &v6_cork);
1784 }
1785
