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
ip6_finish_output2(struct net * net,struct sock * sk,struct sk_buff * skb)60 static 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
146 static int
ip6_finish_output_gso_slowpath_drop(struct net * net,struct sock * sk,struct sk_buff * skb,unsigned int mtu)147 ip6_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
ip6_finish_output_gso(struct net * net,struct sock * sk,struct sk_buff * skb,unsigned int mtu)185 static 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
__ip6_finish_output(struct net * net,struct sock * sk,struct sk_buff * skb)195 static 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
ip6_finish_output(struct net * net,struct sock * sk,struct sk_buff * skb)218 static 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
ip6_output(struct net * net,struct sock * sk,struct sk_buff * skb)233 int 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 }
252 EXPORT_SYMBOL(ip6_output);
253
ip6_autoflowlabel(struct net * net,const struct sock * sk)254 bool 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 */
ip6_xmit(const struct sock * sk,struct sk_buff * skb,struct flowi6 * fl6,__u32 mark,struct ipv6_txoptions * opt,int tclass,u32 priority)267 int 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 }
381 EXPORT_SYMBOL(ip6_xmit);
382
ip6_call_ra_chain(struct sk_buff * skb,int sel)383 static 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
ip6_forward_proxy_check(struct sk_buff * skb)417 static 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
ip6_forward_finish(struct net * net,struct sock * sk,struct sk_buff * skb)469 static 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
ip6_pkt_too_big(const struct sk_buff * skb,unsigned int mtu)483 static 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
ip6_forward(struct sk_buff * skb)501 int 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
672 error:
673 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
674 SKB_DR_SET(reason, IP_INADDRERRORS);
675 drop:
676 kfree_skb_reason(skb, reason);
677 return -EINVAL;
678 }
679
ip6_copy_metadata(struct sk_buff * to,struct sk_buff * from)680 static 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
ip6_fraglist_init(struct sk_buff * skb,unsigned int hlen,u8 * prevhdr,u8 nexthdr,__be32 frag_id,struct ip6_fraglist_iter * iter)700 int 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 }
739 EXPORT_SYMBOL(ip6_fraglist_init);
740
ip6_fraglist_prepare(struct sk_buff * skb,struct ip6_fraglist_iter * iter)741 void 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 }
764 EXPORT_SYMBOL(ip6_fraglist_prepare);
765
ip6_frag_init(struct sk_buff * skb,unsigned int hlen,unsigned int mtu,unsigned short needed_tailroom,int hdr_room,u8 * prevhdr,u8 nexthdr,__be32 frag_id,struct ip6_frag_state * state)766 void 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 }
785 EXPORT_SYMBOL(ip6_frag_init);
786
ip6_frag_next(struct sk_buff * skb,struct ip6_frag_state * state)787 struct 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 }
861 EXPORT_SYMBOL(ip6_frag_next);
862
ip6_fragment(struct net * net,struct sock * sk,struct sk_buff * skb,int (* output)(struct net *,struct sock *,struct sk_buff *))863 int 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
994 slow_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
1004 slow_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
1040 fail_toobig:
1041 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1042 err = -EMSGSIZE;
1043
1044 fail:
1045 IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
1046 IPSTATS_MIB_FRAGFAILS);
1047 kfree_skb(skb);
1048 return err;
1049 }
1050
ip6_rt_check(const struct rt6key * rt_key,const struct in6_addr * fl_addr,const struct in6_addr * addr_cache)1051 static 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
ip6_sk_dst_check(struct sock * sk,struct dst_entry * dst,const struct flowi6 * fl6)1059 static 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
1101 out:
1102 return dst;
1103 }
1104
ip6_dst_lookup_tail(struct net * net,const struct sock * sk,struct dst_entry ** dst,struct flowi6 * fl6)1105 static 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
1213 out_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 */
ip6_dst_lookup(struct net * net,struct sock * sk,struct dst_entry ** dst,struct flowi6 * fl6)1233 int 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 }
1239 EXPORT_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 */
ip6_dst_lookup_flow(struct net * net,const struct sock * sk,struct flowi6 * fl6,const struct in6_addr * final_dst)1253 struct 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 }
1267 EXPORT_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 */
ip6_sk_dst_lookup_flow(struct sock * sk,struct flowi6 * fl6,const struct in6_addr * final_dst,bool connected)1287 struct 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 }
1303 EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow);
1304
ip6_opt_dup(struct ipv6_opt_hdr * src,gfp_t gfp)1305 static 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
ip6_rthdr_dup(struct ipv6_rt_hdr * src,gfp_t gfp)1311 static 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
ip6_append_data_mtu(unsigned int * mtu,int * maxfraglen,unsigned int fragheaderlen,struct sk_buff * skb,struct rt6_info * rt,unsigned int orig_mtu)1317 static 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
ip6_setup_cork(struct sock * sk,struct inet_cork_full * cork,struct inet6_cork * v6_cork,struct ipcm6_cookie * ipc6,struct rt6_info * rt)1341 static 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 v6_cork->dontfrag = ipc6->dontfrag;
1390 if (rt->dst.flags & DST_XFRM_TUNNEL)
1391 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1392 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
1393 else
1394 mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1395 READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
1396
1397 frag_size = READ_ONCE(np->frag_size);
1398 if (frag_size && frag_size < mtu)
1399 mtu = frag_size;
1400
1401 cork->base.fragsize = mtu;
1402 cork->base.gso_size = ipc6->gso_size;
1403 cork->base.tx_flags = 0;
1404 cork->base.mark = ipc6->sockc.mark;
1405 cork->base.priority = ipc6->sockc.priority;
1406 sock_tx_timestamp(sk, &ipc6->sockc, &cork->base.tx_flags);
1407 if (ipc6->sockc.tsflags & SOCKCM_FLAG_TS_OPT_ID) {
1408 cork->base.flags |= IPCORK_TS_OPT_ID;
1409 cork->base.ts_opt_id = ipc6->sockc.ts_opt_id;
1410 }
1411 cork->base.length = 0;
1412 cork->base.transmit_time = ipc6->sockc.transmit_time;
1413
1414 return 0;
1415 }
1416
__ip6_append_data(struct sock * sk,struct sk_buff_head * queue,struct inet_cork_full * cork_full,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,size_t length,int transhdrlen,unsigned int flags)1417 static int __ip6_append_data(struct sock *sk,
1418 struct sk_buff_head *queue,
1419 struct inet_cork_full *cork_full,
1420 struct inet6_cork *v6_cork,
1421 struct page_frag *pfrag,
1422 int getfrag(void *from, char *to, int offset,
1423 int len, int odd, struct sk_buff *skb),
1424 void *from, size_t length, int transhdrlen,
1425 unsigned int flags)
1426 {
1427 struct sk_buff *skb, *skb_prev = NULL;
1428 struct inet_cork *cork = &cork_full->base;
1429 struct flowi6 *fl6 = &cork_full->fl.u.ip6;
1430 unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
1431 struct ubuf_info *uarg = NULL;
1432 int exthdrlen = 0;
1433 int dst_exthdrlen = 0;
1434 int hh_len;
1435 int copy;
1436 int err;
1437 int offset = 0;
1438 bool zc = false;
1439 u32 tskey = 0;
1440 struct rt6_info *rt = dst_rt6_info(cork->dst);
1441 bool paged, hold_tskey = false, extra_uref = false;
1442 struct ipv6_txoptions *opt = v6_cork->opt;
1443 int csummode = CHECKSUM_NONE;
1444 unsigned int maxnonfragsize, headersize;
1445 unsigned int wmem_alloc_delta = 0;
1446
1447 skb = skb_peek_tail(queue);
1448 if (!skb) {
1449 exthdrlen = opt ? opt->opt_flen : 0;
1450 dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
1451 }
1452
1453 paged = !!cork->gso_size;
1454 mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
1455 orig_mtu = mtu;
1456
1457 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1458
1459 fragheaderlen = sizeof(struct ipv6hdr) + rt->rt6i_nfheader_len +
1460 (opt ? opt->opt_nflen : 0);
1461
1462 headersize = sizeof(struct ipv6hdr) +
1463 (opt ? opt->opt_flen + opt->opt_nflen : 0) +
1464 rt->rt6i_nfheader_len;
1465
1466 if (mtu <= fragheaderlen ||
1467 ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
1468 goto emsgsize;
1469
1470 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1471 sizeof(struct frag_hdr);
1472
1473 /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit
1474 * the first fragment
1475 */
1476 if (headersize + transhdrlen > mtu)
1477 goto emsgsize;
1478
1479 if (cork->length + length > mtu - headersize && v6_cork->dontfrag &&
1480 (sk->sk_protocol == IPPROTO_UDP ||
1481 sk->sk_protocol == IPPROTO_ICMPV6 ||
1482 sk->sk_protocol == IPPROTO_RAW)) {
1483 ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1484 sizeof(struct ipv6hdr));
1485 goto emsgsize;
1486 }
1487
1488 if (ip6_sk_ignore_df(sk))
1489 maxnonfragsize = sizeof(struct ipv6hdr) + IPV6_MAXPLEN;
1490 else
1491 maxnonfragsize = mtu;
1492
1493 if (cork->length + length > maxnonfragsize - headersize) {
1494 emsgsize:
1495 pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
1496 ipv6_local_error(sk, EMSGSIZE, fl6, pmtu);
1497 return -EMSGSIZE;
1498 }
1499
1500 /* CHECKSUM_PARTIAL only with no extension headers and when
1501 * we are not going to fragment
1502 */
1503 if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
1504 headersize == sizeof(struct ipv6hdr) &&
1505 length <= mtu - headersize &&
1506 (!(flags & MSG_MORE) || cork->gso_size) &&
1507 rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
1508 csummode = CHECKSUM_PARTIAL;
1509
1510 if ((flags & MSG_ZEROCOPY) && length) {
1511 struct msghdr *msg = from;
1512
1513 if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {
1514 if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))
1515 return -EINVAL;
1516
1517 /* Leave uarg NULL if can't zerocopy, callers should
1518 * be able to handle it.
1519 */
1520 if ((rt->dst.dev->features & NETIF_F_SG) &&
1521 csummode == CHECKSUM_PARTIAL) {
1522 paged = true;
1523 zc = true;
1524 uarg = msg->msg_ubuf;
1525 }
1526 } else if (sock_flag(sk, SOCK_ZEROCOPY)) {
1527 uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
1528 if (!uarg)
1529 return -ENOBUFS;
1530 extra_uref = !skb_zcopy(skb); /* only ref on new uarg */
1531 if (rt->dst.dev->features & NETIF_F_SG &&
1532 csummode == CHECKSUM_PARTIAL) {
1533 paged = true;
1534 zc = true;
1535 } else {
1536 uarg_to_msgzc(uarg)->zerocopy = 0;
1537 skb_zcopy_set(skb, uarg, &extra_uref);
1538 }
1539 }
1540 } else if ((flags & MSG_SPLICE_PAGES) && length) {
1541 if (inet_test_bit(HDRINCL, sk))
1542 return -EPERM;
1543 if (rt->dst.dev->features & NETIF_F_SG &&
1544 getfrag == ip_generic_getfrag)
1545 /* We need an empty buffer to attach stuff to */
1546 paged = true;
1547 else
1548 flags &= ~MSG_SPLICE_PAGES;
1549 }
1550
1551 if (cork->tx_flags & SKBTX_ANY_TSTAMP &&
1552 READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_ID) {
1553 if (cork->flags & IPCORK_TS_OPT_ID) {
1554 tskey = cork->ts_opt_id;
1555 } else {
1556 tskey = atomic_inc_return(&sk->sk_tskey) - 1;
1557 hold_tskey = true;
1558 }
1559 }
1560
1561 /*
1562 * Let's try using as much space as possible.
1563 * Use MTU if total length of the message fits into the MTU.
1564 * Otherwise, we need to reserve fragment header and
1565 * fragment alignment (= 8-15 octects, in total).
1566 *
1567 * Note that we may need to "move" the data from the tail
1568 * of the buffer to the new fragment when we split
1569 * the message.
1570 *
1571 * FIXME: It may be fragmented into multiple chunks
1572 * at once if non-fragmentable extension headers
1573 * are too large.
1574 * --yoshfuji
1575 */
1576
1577 cork->length += length;
1578 if (!skb)
1579 goto alloc_new_skb;
1580
1581 while (length > 0) {
1582 /* Check if the remaining data fits into current packet. */
1583 copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len;
1584 if (copy < length)
1585 copy = maxfraglen - skb->len;
1586
1587 if (copy <= 0) {
1588 char *data;
1589 unsigned int datalen;
1590 unsigned int fraglen;
1591 unsigned int fraggap;
1592 unsigned int alloclen, alloc_extra;
1593 unsigned int pagedlen;
1594 alloc_new_skb:
1595 /* There's no room in the current skb */
1596 if (skb)
1597 fraggap = skb->len - maxfraglen;
1598 else
1599 fraggap = 0;
1600 /* update mtu and maxfraglen if necessary */
1601 if (!skb || !skb_prev)
1602 ip6_append_data_mtu(&mtu, &maxfraglen,
1603 fragheaderlen, skb, rt,
1604 orig_mtu);
1605
1606 skb_prev = skb;
1607
1608 /*
1609 * If remaining data exceeds the mtu,
1610 * we know we need more fragment(s).
1611 */
1612 datalen = length + fraggap;
1613
1614 if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen)
1615 datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
1616 fraglen = datalen + fragheaderlen;
1617 pagedlen = 0;
1618
1619 alloc_extra = hh_len;
1620 alloc_extra += dst_exthdrlen;
1621 alloc_extra += rt->dst.trailer_len;
1622
1623 /* We just reserve space for fragment header.
1624 * Note: this may be overallocation if the message
1625 * (without MSG_MORE) fits into the MTU.
1626 */
1627 alloc_extra += sizeof(struct frag_hdr);
1628
1629 if ((flags & MSG_MORE) &&
1630 !(rt->dst.dev->features&NETIF_F_SG))
1631 alloclen = mtu;
1632 else if (!paged &&
1633 (fraglen + alloc_extra < SKB_MAX_ALLOC ||
1634 !(rt->dst.dev->features & NETIF_F_SG)))
1635 alloclen = fraglen;
1636 else {
1637 alloclen = fragheaderlen + transhdrlen;
1638 pagedlen = datalen - transhdrlen;
1639 }
1640 alloclen += alloc_extra;
1641
1642 if (datalen != length + fraggap) {
1643 /*
1644 * this is not the last fragment, the trailer
1645 * space is regarded as data space.
1646 */
1647 datalen += rt->dst.trailer_len;
1648 }
1649
1650 fraglen = datalen + fragheaderlen;
1651
1652 copy = datalen - transhdrlen - fraggap - pagedlen;
1653 /* [!] NOTE: copy may be negative if pagedlen>0
1654 * because then the equation may reduces to -fraggap.
1655 */
1656 if (copy < 0 && !(flags & MSG_SPLICE_PAGES)) {
1657 err = -EINVAL;
1658 goto error;
1659 }
1660 if (transhdrlen) {
1661 skb = sock_alloc_send_skb(sk, alloclen,
1662 (flags & MSG_DONTWAIT), &err);
1663 } else {
1664 skb = NULL;
1665 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
1666 2 * sk->sk_sndbuf)
1667 skb = alloc_skb(alloclen,
1668 sk->sk_allocation);
1669 if (unlikely(!skb))
1670 err = -ENOBUFS;
1671 }
1672 if (!skb)
1673 goto error;
1674 /*
1675 * Fill in the control structures
1676 */
1677 skb->protocol = htons(ETH_P_IPV6);
1678 skb->ip_summed = csummode;
1679 skb->csum = 0;
1680 /* reserve for fragmentation and ipsec header */
1681 skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
1682 dst_exthdrlen);
1683
1684 /*
1685 * Find where to start putting bytes
1686 */
1687 data = skb_put(skb, fraglen - pagedlen);
1688 skb_set_network_header(skb, exthdrlen);
1689 data += fragheaderlen;
1690 skb->transport_header = (skb->network_header +
1691 fragheaderlen);
1692 if (fraggap) {
1693 skb->csum = skb_copy_and_csum_bits(
1694 skb_prev, maxfraglen,
1695 data + transhdrlen, fraggap);
1696 skb_prev->csum = csum_sub(skb_prev->csum,
1697 skb->csum);
1698 data += fraggap;
1699 pskb_trim_unique(skb_prev, maxfraglen);
1700 }
1701 if (copy > 0 &&
1702 INDIRECT_CALL_1(getfrag, ip_generic_getfrag,
1703 from, data + transhdrlen, offset,
1704 copy, fraggap, skb) < 0) {
1705 err = -EFAULT;
1706 kfree_skb(skb);
1707 goto error;
1708 } else if (flags & MSG_SPLICE_PAGES) {
1709 copy = 0;
1710 }
1711
1712 offset += copy;
1713 length -= copy + transhdrlen;
1714 transhdrlen = 0;
1715 exthdrlen = 0;
1716 dst_exthdrlen = 0;
1717
1718 /* Only the initial fragment is time stamped */
1719 skb_shinfo(skb)->tx_flags = cork->tx_flags;
1720 cork->tx_flags = 0;
1721 skb_shinfo(skb)->tskey = tskey;
1722 tskey = 0;
1723 skb_zcopy_set(skb, uarg, &extra_uref);
1724
1725 if ((flags & MSG_CONFIRM) && !skb_prev)
1726 skb_set_dst_pending_confirm(skb, 1);
1727
1728 /*
1729 * Put the packet on the pending queue
1730 */
1731 if (!skb->destructor) {
1732 skb->destructor = sock_wfree;
1733 skb->sk = sk;
1734 wmem_alloc_delta += skb->truesize;
1735 }
1736 __skb_queue_tail(queue, skb);
1737 continue;
1738 }
1739
1740 if (copy > length)
1741 copy = length;
1742
1743 if (!(rt->dst.dev->features&NETIF_F_SG) &&
1744 skb_tailroom(skb) >= copy) {
1745 unsigned int off;
1746
1747 off = skb->len;
1748 if (INDIRECT_CALL_1(getfrag, ip_generic_getfrag,
1749 from, skb_put(skb, copy),
1750 offset, copy, off, skb) < 0) {
1751 __skb_trim(skb, off);
1752 err = -EFAULT;
1753 goto error;
1754 }
1755 } else if (flags & MSG_SPLICE_PAGES) {
1756 struct msghdr *msg = from;
1757
1758 err = -EIO;
1759 if (WARN_ON_ONCE(copy > msg->msg_iter.count))
1760 goto error;
1761
1762 err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
1763 sk->sk_allocation);
1764 if (err < 0)
1765 goto error;
1766 copy = err;
1767 wmem_alloc_delta += copy;
1768 } else if (!zc) {
1769 int i = skb_shinfo(skb)->nr_frags;
1770
1771 err = -ENOMEM;
1772 if (!sk_page_frag_refill(sk, pfrag))
1773 goto error;
1774
1775 skb_zcopy_downgrade_managed(skb);
1776 if (!skb_can_coalesce(skb, i, pfrag->page,
1777 pfrag->offset)) {
1778 err = -EMSGSIZE;
1779 if (i == MAX_SKB_FRAGS)
1780 goto error;
1781
1782 __skb_fill_page_desc(skb, i, pfrag->page,
1783 pfrag->offset, 0);
1784 skb_shinfo(skb)->nr_frags = ++i;
1785 get_page(pfrag->page);
1786 }
1787 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1788 if (INDIRECT_CALL_1(getfrag, ip_generic_getfrag,
1789 from,
1790 page_address(pfrag->page) + pfrag->offset,
1791 offset, copy, skb->len, skb) < 0)
1792 goto error_efault;
1793
1794 pfrag->offset += copy;
1795 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1796 skb->len += copy;
1797 skb->data_len += copy;
1798 skb->truesize += copy;
1799 wmem_alloc_delta += copy;
1800 } else {
1801 err = skb_zerocopy_iter_dgram(skb, from, copy);
1802 if (err < 0)
1803 goto error;
1804 }
1805 offset += copy;
1806 length -= copy;
1807 }
1808
1809 if (wmem_alloc_delta)
1810 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1811 return 0;
1812
1813 error_efault:
1814 err = -EFAULT;
1815 error:
1816 net_zcopy_put_abort(uarg, extra_uref);
1817 cork->length -= length;
1818 IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
1819 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1820 if (hold_tskey)
1821 atomic_dec(&sk->sk_tskey);
1822 return err;
1823 }
1824
ip6_append_data(struct sock * sk,int getfrag (void * from,char * to,int offset,int len,int odd,struct sk_buff * skb),void * from,size_t length,int transhdrlen,struct ipcm6_cookie * ipc6,struct flowi6 * fl6,struct rt6_info * rt,unsigned int flags)1825 int ip6_append_data(struct sock *sk,
1826 int getfrag(void *from, char *to, int offset, int len,
1827 int odd, struct sk_buff *skb),
1828 void *from, size_t length, int transhdrlen,
1829 struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
1830 struct rt6_info *rt, unsigned int flags)
1831 {
1832 struct inet_sock *inet = inet_sk(sk);
1833 struct ipv6_pinfo *np = inet6_sk(sk);
1834 int exthdrlen;
1835 int err;
1836
1837 if (flags&MSG_PROBE)
1838 return 0;
1839 if (skb_queue_empty(&sk->sk_write_queue)) {
1840 /*
1841 * setup for corking
1842 */
1843 dst_hold(&rt->dst);
1844 err = ip6_setup_cork(sk, &inet->cork, &np->cork,
1845 ipc6, rt);
1846 if (err)
1847 return err;
1848
1849 inet->cork.fl.u.ip6 = *fl6;
1850 exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
1851 length += exthdrlen;
1852 transhdrlen += exthdrlen;
1853 } else {
1854 transhdrlen = 0;
1855 }
1856
1857 return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork,
1858 &np->cork, sk_page_frag(sk), getfrag,
1859 from, length, transhdrlen, flags);
1860 }
1861 EXPORT_SYMBOL_GPL(ip6_append_data);
1862
ip6_cork_steal_dst(struct sk_buff * skb,struct inet_cork_full * cork)1863 static void ip6_cork_steal_dst(struct sk_buff *skb, struct inet_cork_full *cork)
1864 {
1865 struct dst_entry *dst = cork->base.dst;
1866
1867 cork->base.dst = NULL;
1868 skb_dst_set(skb, dst);
1869 }
1870
ip6_cork_release(struct inet_cork_full * cork,struct inet6_cork * v6_cork)1871 static void ip6_cork_release(struct inet_cork_full *cork,
1872 struct inet6_cork *v6_cork)
1873 {
1874 if (v6_cork->opt) {
1875 struct ipv6_txoptions *opt = v6_cork->opt;
1876
1877 kfree(opt->dst0opt);
1878 kfree(opt->dst1opt);
1879 kfree(opt->hopopt);
1880 kfree(opt->srcrt);
1881 kfree(opt);
1882 v6_cork->opt = NULL;
1883 }
1884
1885 if (cork->base.dst) {
1886 dst_release(cork->base.dst);
1887 cork->base.dst = NULL;
1888 }
1889 }
1890
__ip6_make_skb(struct sock * sk,struct sk_buff_head * queue,struct inet_cork_full * cork,struct inet6_cork * v6_cork)1891 struct sk_buff *__ip6_make_skb(struct sock *sk,
1892 struct sk_buff_head *queue,
1893 struct inet_cork_full *cork,
1894 struct inet6_cork *v6_cork)
1895 {
1896 struct sk_buff *skb, *tmp_skb;
1897 struct sk_buff **tail_skb;
1898 struct in6_addr *final_dst;
1899 struct net *net = sock_net(sk);
1900 struct ipv6hdr *hdr;
1901 struct ipv6_txoptions *opt = v6_cork->opt;
1902 struct rt6_info *rt = dst_rt6_info(cork->base.dst);
1903 struct flowi6 *fl6 = &cork->fl.u.ip6;
1904 unsigned char proto = fl6->flowi6_proto;
1905
1906 skb = __skb_dequeue(queue);
1907 if (!skb)
1908 goto out;
1909 tail_skb = &(skb_shinfo(skb)->frag_list);
1910
1911 /* move skb->data to ip header from ext header */
1912 if (skb->data < skb_network_header(skb))
1913 __skb_pull(skb, skb_network_offset(skb));
1914 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1915 __skb_pull(tmp_skb, skb_network_header_len(skb));
1916 *tail_skb = tmp_skb;
1917 tail_skb = &(tmp_skb->next);
1918 skb->len += tmp_skb->len;
1919 skb->data_len += tmp_skb->len;
1920 skb->truesize += tmp_skb->truesize;
1921 tmp_skb->destructor = NULL;
1922 tmp_skb->sk = NULL;
1923 }
1924
1925 /* Allow local fragmentation. */
1926 skb->ignore_df = ip6_sk_ignore_df(sk);
1927 __skb_pull(skb, skb_network_header_len(skb));
1928
1929 final_dst = &fl6->daddr;
1930 if (opt && opt->opt_flen)
1931 ipv6_push_frag_opts(skb, opt, &proto);
1932 if (opt && opt->opt_nflen)
1933 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);
1934
1935 skb_push(skb, sizeof(struct ipv6hdr));
1936 skb_reset_network_header(skb);
1937 hdr = ipv6_hdr(skb);
1938
1939 ip6_flow_hdr(hdr, v6_cork->tclass,
1940 ip6_make_flowlabel(net, skb, fl6->flowlabel,
1941 ip6_autoflowlabel(net, sk), fl6));
1942 hdr->hop_limit = v6_cork->hop_limit;
1943 hdr->nexthdr = proto;
1944 hdr->saddr = fl6->saddr;
1945 hdr->daddr = *final_dst;
1946
1947 skb->priority = cork->base.priority;
1948 skb->mark = cork->base.mark;
1949 if (sk_is_tcp(sk))
1950 skb_set_delivery_time(skb, cork->base.transmit_time, SKB_CLOCK_MONOTONIC);
1951 else
1952 skb_set_delivery_type_by_clockid(skb, cork->base.transmit_time, sk->sk_clockid);
1953
1954 ip6_cork_steal_dst(skb, cork);
1955 IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);
1956 if (proto == IPPROTO_ICMPV6) {
1957 struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
1958 u8 icmp6_type;
1959
1960 if (sk->sk_socket->type == SOCK_RAW &&
1961 !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH))
1962 icmp6_type = fl6->fl6_icmp_type;
1963 else
1964 icmp6_type = icmp6_hdr(skb)->icmp6_type;
1965 ICMP6MSGOUT_INC_STATS(net, idev, icmp6_type);
1966 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
1967 }
1968
1969 ip6_cork_release(cork, v6_cork);
1970 out:
1971 return skb;
1972 }
1973
ip6_send_skb(struct sk_buff * skb)1974 int ip6_send_skb(struct sk_buff *skb)
1975 {
1976 struct net *net = sock_net(skb->sk);
1977 struct rt6_info *rt = dst_rt6_info(skb_dst(skb));
1978 int err;
1979
1980 rcu_read_lock();
1981 err = ip6_local_out(net, skb->sk, skb);
1982 if (err) {
1983 if (err > 0)
1984 err = net_xmit_errno(err);
1985 if (err)
1986 IP6_INC_STATS(net, rt->rt6i_idev,
1987 IPSTATS_MIB_OUTDISCARDS);
1988 }
1989
1990 rcu_read_unlock();
1991 return err;
1992 }
1993
ip6_push_pending_frames(struct sock * sk)1994 int ip6_push_pending_frames(struct sock *sk)
1995 {
1996 struct sk_buff *skb;
1997
1998 skb = ip6_finish_skb(sk);
1999 if (!skb)
2000 return 0;
2001
2002 return ip6_send_skb(skb);
2003 }
2004 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
2005
__ip6_flush_pending_frames(struct sock * sk,struct sk_buff_head * queue,struct inet_cork_full * cork,struct inet6_cork * v6_cork)2006 static void __ip6_flush_pending_frames(struct sock *sk,
2007 struct sk_buff_head *queue,
2008 struct inet_cork_full *cork,
2009 struct inet6_cork *v6_cork)
2010 {
2011 struct sk_buff *skb;
2012
2013 while ((skb = __skb_dequeue_tail(queue)) != NULL) {
2014 if (skb_dst(skb))
2015 IP6_INC_STATS(sock_net(sk), ip6_dst_idev(skb_dst(skb)),
2016 IPSTATS_MIB_OUTDISCARDS);
2017 kfree_skb(skb);
2018 }
2019
2020 ip6_cork_release(cork, v6_cork);
2021 }
2022
ip6_flush_pending_frames(struct sock * sk)2023 void ip6_flush_pending_frames(struct sock *sk)
2024 {
2025 __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
2026 &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
2027 }
2028 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
2029
ip6_make_skb(struct sock * sk,int getfrag (void * from,char * to,int offset,int len,int odd,struct sk_buff * skb),void * from,size_t length,int transhdrlen,struct ipcm6_cookie * ipc6,struct rt6_info * rt,unsigned int flags,struct inet_cork_full * cork)2030 struct sk_buff *ip6_make_skb(struct sock *sk,
2031 int getfrag(void *from, char *to, int offset,
2032 int len, int odd, struct sk_buff *skb),
2033 void *from, size_t length, int transhdrlen,
2034 struct ipcm6_cookie *ipc6, struct rt6_info *rt,
2035 unsigned int flags, struct inet_cork_full *cork)
2036 {
2037 struct inet6_cork v6_cork;
2038 struct sk_buff_head queue;
2039 int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
2040 int err;
2041
2042 if (flags & MSG_PROBE) {
2043 dst_release(&rt->dst);
2044 return NULL;
2045 }
2046
2047 __skb_queue_head_init(&queue);
2048
2049 cork->base.flags = 0;
2050 cork->base.addr = 0;
2051 cork->base.opt = NULL;
2052 v6_cork.opt = NULL;
2053 err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt);
2054 if (err) {
2055 ip6_cork_release(cork, &v6_cork);
2056 return ERR_PTR(err);
2057 }
2058
2059 err = __ip6_append_data(sk, &queue, cork, &v6_cork,
2060 ¤t->task_frag, getfrag, from,
2061 length + exthdrlen, transhdrlen + exthdrlen,
2062 flags);
2063 if (err) {
2064 __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
2065 return ERR_PTR(err);
2066 }
2067
2068 return __ip6_make_skb(sk, &queue, cork, &v6_cork);
2069 }
2070