Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * xfrm_output.c - Common IPsec encapsulation code.
4 *
5 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8#include <linux/errno.h>
9#include <linux/module.h>
10#include <linux/netdevice.h>
11#include <linux/netfilter.h>
12#include <linux/skbuff.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <net/dst.h>
16#include <net/icmp.h>
17#include <net/inet_ecn.h>
18#include <net/xfrm.h>
19
20#if IS_ENABLED(CONFIG_IPV6)
21#include <net/ip6_route.h>
22#include <net/ipv6_stubs.h>
23#endif
24
25#include "xfrm_inout.h"
26
27static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
28static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
29
30static int xfrm_skb_check_space(struct sk_buff *skb)
31{
32 struct dst_entry *dst = skb_dst(skb);
33 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
34 - skb_headroom(skb);
35 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
36
37 if (nhead <= 0) {
38 if (ntail <= 0)
39 return 0;
40 nhead = 0;
41 } else if (ntail < 0)
42 ntail = 0;
43
44 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
45}
46
47/* Children define the path of the packet through the
48 * Linux networking. Thus, destinations are stackable.
49 */
50
51static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
52{
53 struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
54
55 skb_dst_drop(skb);
56 return child;
57}
58
59/* Add encapsulation header.
60 *
61 * The IP header will be moved forward to make space for the encapsulation
62 * header.
63 */
64static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
65{
66 struct iphdr *iph = ip_hdr(skb);
67 int ihl = iph->ihl * 4;
68
69 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
70
71 skb_set_network_header(skb, -x->props.header_len);
72 skb->mac_header = skb->network_header +
73 offsetof(struct iphdr, protocol);
74 skb->transport_header = skb->network_header + ihl;
75 __skb_pull(skb, ihl);
76 memmove(skb_network_header(skb), iph, ihl);
77 return 0;
78}
79
80#if IS_ENABLED(CONFIG_IPV6_MIP6)
81static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
82{
83 const unsigned char *nh = skb_network_header(skb);
84 unsigned int offset = sizeof(struct ipv6hdr);
85 unsigned int packet_len;
86 int found_rhdr = 0;
87
88 packet_len = skb_tail_pointer(skb) - nh;
89 *nexthdr = &ipv6_hdr(skb)->nexthdr;
90
91 while (offset <= packet_len) {
92 struct ipv6_opt_hdr *exthdr;
93
94 switch (**nexthdr) {
95 case NEXTHDR_HOP:
96 break;
97 case NEXTHDR_ROUTING:
98 if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
99 struct ipv6_rt_hdr *rt;
100
101 rt = (struct ipv6_rt_hdr *)(nh + offset);
102 if (rt->type != 0)
103 return offset;
104 }
105 found_rhdr = 1;
106 break;
107 case NEXTHDR_DEST:
108 /* HAO MUST NOT appear more than once.
109 * XXX: It is better to try to find by the end of
110 * XXX: packet if HAO exists.
111 */
112 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
113 net_dbg_ratelimited("mip6: hao exists already, override\n");
114 return offset;
115 }
116
117 if (found_rhdr)
118 return offset;
119
120 break;
121 default:
122 return offset;
123 }
124
125 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
126 return -EINVAL;
127
128 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
129 offset);
130 offset += ipv6_optlen(exthdr);
131 if (offset > IPV6_MAXPLEN)
132 return -EINVAL;
133 *nexthdr = &exthdr->nexthdr;
134 }
135
136 return -EINVAL;
137}
138#endif
139
140#if IS_ENABLED(CONFIG_IPV6)
141static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
142{
143 switch (x->type->proto) {
144#if IS_ENABLED(CONFIG_IPV6_MIP6)
145 case IPPROTO_DSTOPTS:
146 case IPPROTO_ROUTING:
147 return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
148#endif
149 default:
150 break;
151 }
152
153 return ip6_find_1stfragopt(skb, prevhdr);
154}
155#endif
156
157/* Add encapsulation header.
158 *
159 * The IP header and mutable extension headers will be moved forward to make
160 * space for the encapsulation header.
161 */
162static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
163{
164#if IS_ENABLED(CONFIG_IPV6)
165 struct ipv6hdr *iph;
166 u8 *prevhdr;
167 int hdr_len;
168
169 iph = ipv6_hdr(skb);
170 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
171
172 hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
173 if (hdr_len < 0)
174 return hdr_len;
175 skb_set_mac_header(skb,
176 (prevhdr - x->props.header_len) - skb->data);
177 skb_set_network_header(skb, -x->props.header_len);
178 skb->transport_header = skb->network_header + hdr_len;
179 __skb_pull(skb, hdr_len);
180 memmove(ipv6_hdr(skb), iph, hdr_len);
181 return 0;
182#else
183 WARN_ON_ONCE(1);
184 return -EAFNOSUPPORT;
185#endif
186}
187
188/* Add route optimization header space.
189 *
190 * The IP header and mutable extension headers will be moved forward to make
191 * space for the route optimization header.
192 */
193static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
194{
195#if IS_ENABLED(CONFIG_IPV6)
196 struct ipv6hdr *iph;
197 u8 *prevhdr;
198 int hdr_len;
199
200 iph = ipv6_hdr(skb);
201
202 hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
203 if (hdr_len < 0)
204 return hdr_len;
205 skb_set_mac_header(skb,
206 (prevhdr - x->props.header_len) - skb->data);
207 skb_set_network_header(skb, -x->props.header_len);
208 skb->transport_header = skb->network_header + hdr_len;
209 __skb_pull(skb, hdr_len);
210 memmove(ipv6_hdr(skb), iph, hdr_len);
211
212 return 0;
213#else
214 WARN_ON_ONCE(1);
215 return -EAFNOSUPPORT;
216#endif
217}
218
219/* Add encapsulation header.
220 *
221 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
222 */
223static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
224{
225 struct ip_beet_phdr *ph;
226 struct iphdr *top_iph;
227 int hdrlen, optlen;
228
229 hdrlen = 0;
230 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
231 if (unlikely(optlen))
232 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
233
234 skb_set_network_header(skb, -x->props.header_len - hdrlen +
235 (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
236 if (x->sel.family != AF_INET6)
237 skb->network_header += IPV4_BEET_PHMAXLEN;
238 skb->mac_header = skb->network_header +
239 offsetof(struct iphdr, protocol);
240 skb->transport_header = skb->network_header + sizeof(*top_iph);
241
242 xfrm4_beet_make_header(skb);
243
244 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
245
246 top_iph = ip_hdr(skb);
247
248 if (unlikely(optlen)) {
249 if (WARN_ON(optlen < 0))
250 return -EINVAL;
251
252 ph->padlen = 4 - (optlen & 4);
253 ph->hdrlen = optlen / 8;
254 ph->nexthdr = top_iph->protocol;
255 if (ph->padlen)
256 memset(ph + 1, IPOPT_NOP, ph->padlen);
257
258 top_iph->protocol = IPPROTO_BEETPH;
259 top_iph->ihl = sizeof(struct iphdr) / 4;
260 }
261
262 top_iph->saddr = x->props.saddr.a4;
263 top_iph->daddr = x->id.daddr.a4;
264
265 return 0;
266}
267
268/* Add encapsulation header.
269 *
270 * The top IP header will be constructed per RFC 2401.
271 */
272static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
273{
274 bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
275 struct dst_entry *dst = skb_dst(skb);
276 struct iphdr *top_iph;
277 int flags;
278
279 skb_set_inner_network_header(skb, skb_network_offset(skb));
280 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
281
282 skb_set_network_header(skb, -x->props.header_len);
283 skb->mac_header = skb->network_header +
284 offsetof(struct iphdr, protocol);
285 skb->transport_header = skb->network_header + sizeof(*top_iph);
286 top_iph = ip_hdr(skb);
287
288 top_iph->ihl = 5;
289 top_iph->version = 4;
290
291 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
292
293 /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
294 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
295 top_iph->tos = 0;
296 else
297 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
298 top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
299 XFRM_MODE_SKB_CB(skb)->tos);
300
301 flags = x->props.flags;
302 if (flags & XFRM_STATE_NOECN)
303 IP_ECN_clear(top_iph);
304
305 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
306 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
307
308 top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
309
310 top_iph->saddr = x->props.saddr.a4;
311 top_iph->daddr = x->id.daddr.a4;
312 ip_select_ident(dev_net(dst->dev), skb, NULL);
313
314 return 0;
315}
316
317#if IS_ENABLED(CONFIG_IPV6)
318static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
319{
320 struct dst_entry *dst = skb_dst(skb);
321 struct ipv6hdr *top_iph;
322 int dsfield;
323
324 skb_set_inner_network_header(skb, skb_network_offset(skb));
325 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
326
327 skb_set_network_header(skb, -x->props.header_len);
328 skb->mac_header = skb->network_header +
329 offsetof(struct ipv6hdr, nexthdr);
330 skb->transport_header = skb->network_header + sizeof(*top_iph);
331 top_iph = ipv6_hdr(skb);
332
333 top_iph->version = 6;
334
335 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
336 sizeof(top_iph->flow_lbl));
337 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
338
339 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
340 dsfield = 0;
341 else
342 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
343 dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
344 if (x->props.flags & XFRM_STATE_NOECN)
345 dsfield &= ~INET_ECN_MASK;
346 ipv6_change_dsfield(top_iph, 0, dsfield);
347 top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
348 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
349 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
350 return 0;
351}
352
353static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
354{
355 struct ipv6hdr *top_iph;
356 struct ip_beet_phdr *ph;
357 int optlen, hdr_len;
358
359 hdr_len = 0;
360 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
361 if (unlikely(optlen))
362 hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
363
364 skb_set_network_header(skb, -x->props.header_len - hdr_len);
365 if (x->sel.family != AF_INET6)
366 skb->network_header += IPV4_BEET_PHMAXLEN;
367 skb->mac_header = skb->network_header +
368 offsetof(struct ipv6hdr, nexthdr);
369 skb->transport_header = skb->network_header + sizeof(*top_iph);
370 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
371
372 xfrm6_beet_make_header(skb);
373
374 top_iph = ipv6_hdr(skb);
375 if (unlikely(optlen)) {
376 if (WARN_ON(optlen < 0))
377 return -EINVAL;
378
379 ph->padlen = 4 - (optlen & 4);
380 ph->hdrlen = optlen / 8;
381 ph->nexthdr = top_iph->nexthdr;
382 if (ph->padlen)
383 memset(ph + 1, IPOPT_NOP, ph->padlen);
384
385 top_iph->nexthdr = IPPROTO_BEETPH;
386 }
387
388 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
389 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
390 return 0;
391}
392#endif
393
394/* Add encapsulation header.
395 *
396 * On exit, the transport header will be set to the start of the
397 * encapsulation header to be filled in by x->type->output and the mac
398 * header will be set to the nextheader (protocol for IPv4) field of the
399 * extension header directly preceding the encapsulation header, or in
400 * its absence, that of the top IP header.
401 * The value of the network header will always point to the top IP header
402 * while skb->data will point to the payload.
403 */
404static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
405{
406 int err;
407
408 err = xfrm_inner_extract_output(x, skb);
409 if (err)
410 return err;
411
412 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
413 skb->protocol = htons(ETH_P_IP);
414
415 switch (x->outer_mode.encap) {
416 case XFRM_MODE_BEET:
417 return xfrm4_beet_encap_add(x, skb);
418 case XFRM_MODE_TUNNEL:
419 return xfrm4_tunnel_encap_add(x, skb);
420 }
421
422 WARN_ON_ONCE(1);
423 return -EOPNOTSUPP;
424}
425
426static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
427{
428#if IS_ENABLED(CONFIG_IPV6)
429 int err;
430
431 err = xfrm_inner_extract_output(x, skb);
432 if (err)
433 return err;
434
435 skb->ignore_df = 1;
436 skb->protocol = htons(ETH_P_IPV6);
437
438 switch (x->outer_mode.encap) {
439 case XFRM_MODE_BEET:
440 return xfrm6_beet_encap_add(x, skb);
441 case XFRM_MODE_TUNNEL:
442 return xfrm6_tunnel_encap_add(x, skb);
443 default:
444 WARN_ON_ONCE(1);
445 return -EOPNOTSUPP;
446 }
447#endif
448 WARN_ON_ONCE(1);
449 return -EAFNOSUPPORT;
450}
451
452static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
453{
454 switch (x->outer_mode.encap) {
455 case XFRM_MODE_BEET:
456 case XFRM_MODE_TUNNEL:
457 if (x->outer_mode.family == AF_INET)
458 return xfrm4_prepare_output(x, skb);
459 if (x->outer_mode.family == AF_INET6)
460 return xfrm6_prepare_output(x, skb);
461 break;
462 case XFRM_MODE_TRANSPORT:
463 if (x->outer_mode.family == AF_INET)
464 return xfrm4_transport_output(x, skb);
465 if (x->outer_mode.family == AF_INET6)
466 return xfrm6_transport_output(x, skb);
467 break;
468 case XFRM_MODE_ROUTEOPTIMIZATION:
469 if (x->outer_mode.family == AF_INET6)
470 return xfrm6_ro_output(x, skb);
471 WARN_ON_ONCE(1);
472 break;
473 default:
474 WARN_ON_ONCE(1);
475 break;
476 }
477
478 return -EOPNOTSUPP;
479}
480
481#if IS_ENABLED(CONFIG_NET_PKTGEN)
482int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
483{
484 return xfrm_outer_mode_output(x, skb);
485}
486EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
487#endif
488
489static int xfrm_output_one(struct sk_buff *skb, int err)
490{
491 struct dst_entry *dst = skb_dst(skb);
492 struct xfrm_state *x = dst->xfrm;
493 struct net *net = xs_net(x);
494
495 if (err <= 0 || x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
496 goto resume;
497
498 do {
499 err = xfrm_skb_check_space(skb);
500 if (err) {
501 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
502 goto error_nolock;
503 }
504
505 skb->mark = xfrm_smark_get(skb->mark, x);
506
507 err = xfrm_outer_mode_output(x, skb);
508 if (err) {
509 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
510 goto error_nolock;
511 }
512
513 spin_lock_bh(&x->lock);
514
515 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
516 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
517 err = -EINVAL;
518 goto error;
519 }
520
521 err = xfrm_state_check_expire(x);
522 if (err) {
523 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
524 goto error;
525 }
526
527 err = xfrm_replay_overflow(x, skb);
528 if (err) {
529 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
530 goto error;
531 }
532
533 x->curlft.bytes += skb->len;
534 x->curlft.packets++;
535 x->lastused = ktime_get_real_seconds();
536
537 spin_unlock_bh(&x->lock);
538
539 skb_dst_force(skb);
540 if (!skb_dst(skb)) {
541 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
542 err = -EHOSTUNREACH;
543 goto error_nolock;
544 }
545
546 if (xfrm_offload(skb)) {
547 x->type_offload->encap(x, skb);
548 } else {
549 /* Inner headers are invalid now. */
550 skb->encapsulation = 0;
551
552 err = x->type->output(x, skb);
553 if (err == -EINPROGRESS)
554 goto out;
555 }
556
557resume:
558 if (err) {
559 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
560 goto error_nolock;
561 }
562
563 dst = skb_dst_pop(skb);
564 if (!dst) {
565 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
566 err = -EHOSTUNREACH;
567 goto error_nolock;
568 }
569 skb_dst_set(skb, dst);
570 x = dst->xfrm;
571 } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
572
573 return 0;
574
575error:
576 spin_unlock_bh(&x->lock);
577error_nolock:
578 kfree_skb(skb);
579out:
580 return err;
581}
582
583int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
584{
585 struct net *net = xs_net(skb_dst(skb)->xfrm);
586
587 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
588 nf_reset_ct(skb);
589
590 err = skb_dst(skb)->ops->local_out(net, sk, skb);
591 if (unlikely(err != 1))
592 goto out;
593
594 if (!skb_dst(skb)->xfrm)
595 return dst_output(net, sk, skb);
596
597 err = nf_hook(skb_dst(skb)->ops->family,
598 NF_INET_POST_ROUTING, net, sk, skb,
599 NULL, skb_dst(skb)->dev, xfrm_output2);
600 if (unlikely(err != 1))
601 goto out;
602 }
603
604 if (err == -EINPROGRESS)
605 err = 0;
606
607out:
608 return err;
609}
610EXPORT_SYMBOL_GPL(xfrm_output_resume);
611
612static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
613{
614 return xfrm_output_resume(sk, skb, 1);
615}
616
617static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
618{
619 struct sk_buff *segs, *nskb;
620
621 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
622 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
623 segs = skb_gso_segment(skb, 0);
624 kfree_skb(skb);
625 if (IS_ERR(segs))
626 return PTR_ERR(segs);
627 if (segs == NULL)
628 return -EINVAL;
629
630 skb_list_walk_safe(segs, segs, nskb) {
631 int err;
632
633 skb_mark_not_on_list(segs);
634 err = xfrm_output2(net, sk, segs);
635
636 if (unlikely(err)) {
637 kfree_skb_list(nskb);
638 return err;
639 }
640 }
641
642 return 0;
643}
644
645/* For partial checksum offload, the outer header checksum is calculated
646 * by software and the inner header checksum is calculated by hardware.
647 * This requires hardware to know the inner packet type to calculate
648 * the inner header checksum. Save inner ip protocol here to avoid
649 * traversing the packet in the vendor's xmit code.
650 * For IPsec tunnel mode save the ip protocol from the IP header of the
651 * plain text packet. Otherwise If the encap type is IPIP, just save
652 * skb->inner_ipproto in any other case get the ip protocol from the IP
653 * header.
654 */
655static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
656{
657 struct xfrm_offload *xo = xfrm_offload(skb);
658 const struct ethhdr *eth;
659
660 if (!xo)
661 return;
662
663 if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
664 switch (x->outer_mode.family) {
665 case AF_INET:
666 xo->inner_ipproto = ip_hdr(skb)->protocol;
667 break;
668 case AF_INET6:
669 xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
670 break;
671 default:
672 break;
673 }
674
675 return;
676 }
677
678 /* non-Tunnel Mode */
679 if (!skb->encapsulation)
680 return;
681
682 if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
683 xo->inner_ipproto = skb->inner_ipproto;
684 return;
685 }
686
687 if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
688 return;
689
690 eth = (struct ethhdr *)skb_inner_mac_header(skb);
691
692 switch (ntohs(eth->h_proto)) {
693 case ETH_P_IPV6:
694 xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
695 break;
696 case ETH_P_IP:
697 xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
698 break;
699 }
700}
701
702int xfrm_output(struct sock *sk, struct sk_buff *skb)
703{
704 struct net *net = dev_net(skb_dst(skb)->dev);
705 struct xfrm_state *x = skb_dst(skb)->xfrm;
706 int err;
707
708 switch (x->outer_mode.family) {
709 case AF_INET:
710 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
711 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
712 break;
713 case AF_INET6:
714 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
715
716 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
717 break;
718 }
719
720 if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) {
721 if (!xfrm_dev_offload_ok(skb, x)) {
722 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
723 kfree_skb(skb);
724 return -EHOSTUNREACH;
725 }
726
727 return xfrm_output_resume(sk, skb, 0);
728 }
729
730 secpath_reset(skb);
731
732 if (xfrm_dev_offload_ok(skb, x)) {
733 struct sec_path *sp;
734
735 sp = secpath_set(skb);
736 if (!sp) {
737 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
738 kfree_skb(skb);
739 return -ENOMEM;
740 }
741
742 sp->olen++;
743 sp->xvec[sp->len++] = x;
744 xfrm_state_hold(x);
745
746 xfrm_get_inner_ipproto(skb, x);
747 skb->encapsulation = 1;
748
749 if (skb_is_gso(skb)) {
750 if (skb->inner_protocol)
751 return xfrm_output_gso(net, sk, skb);
752
753 skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
754 goto out;
755 }
756
757 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
758 goto out;
759 } else {
760 if (skb_is_gso(skb))
761 return xfrm_output_gso(net, sk, skb);
762 }
763
764 if (skb->ip_summed == CHECKSUM_PARTIAL) {
765 err = skb_checksum_help(skb);
766 if (err) {
767 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
768 kfree_skb(skb);
769 return err;
770 }
771 }
772
773out:
774 return xfrm_output2(net, sk, skb);
775}
776EXPORT_SYMBOL_GPL(xfrm_output);
777
778static int xfrm4_tunnel_check_size(struct sk_buff *skb)
779{
780 int mtu, ret = 0;
781
782 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
783 goto out;
784
785 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
786 goto out;
787
788 mtu = dst_mtu(skb_dst(skb));
789 if ((!skb_is_gso(skb) && skb->len > mtu) ||
790 (skb_is_gso(skb) &&
791 !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
792 skb->protocol = htons(ETH_P_IP);
793
794 if (skb->sk)
795 xfrm_local_error(skb, mtu);
796 else
797 icmp_send(skb, ICMP_DEST_UNREACH,
798 ICMP_FRAG_NEEDED, htonl(mtu));
799 ret = -EMSGSIZE;
800 }
801out:
802 return ret;
803}
804
805static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
806{
807 int err;
808
809 if (x->outer_mode.encap == XFRM_MODE_BEET &&
810 ip_is_fragment(ip_hdr(skb))) {
811 net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
812 return -EAFNOSUPPORT;
813 }
814
815 err = xfrm4_tunnel_check_size(skb);
816 if (err)
817 return err;
818
819 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
820
821 xfrm4_extract_header(skb);
822 return 0;
823}
824
825#if IS_ENABLED(CONFIG_IPV6)
826static int xfrm6_tunnel_check_size(struct sk_buff *skb)
827{
828 int mtu, ret = 0;
829 struct dst_entry *dst = skb_dst(skb);
830
831 if (skb->ignore_df)
832 goto out;
833
834 mtu = dst_mtu(dst);
835 if (mtu < IPV6_MIN_MTU)
836 mtu = IPV6_MIN_MTU;
837
838 if ((!skb_is_gso(skb) && skb->len > mtu) ||
839 (skb_is_gso(skb) &&
840 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
841 skb->dev = dst->dev;
842 skb->protocol = htons(ETH_P_IPV6);
843
844 if (xfrm6_local_dontfrag(skb->sk))
845 ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
846 else if (skb->sk)
847 xfrm_local_error(skb, mtu);
848 else
849 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
850 ret = -EMSGSIZE;
851 }
852out:
853 return ret;
854}
855#endif
856
857static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
858{
859#if IS_ENABLED(CONFIG_IPV6)
860 int err;
861
862 err = xfrm6_tunnel_check_size(skb);
863 if (err)
864 return err;
865
866 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
867
868 xfrm6_extract_header(skb);
869 return 0;
870#else
871 WARN_ON_ONCE(1);
872 return -EAFNOSUPPORT;
873#endif
874}
875
876static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
877{
878 const struct xfrm_mode *inner_mode;
879
880 if (x->sel.family == AF_UNSPEC)
881 inner_mode = xfrm_ip2inner_mode(x,
882 xfrm_af2proto(skb_dst(skb)->ops->family));
883 else
884 inner_mode = &x->inner_mode;
885
886 if (inner_mode == NULL)
887 return -EAFNOSUPPORT;
888
889 switch (inner_mode->family) {
890 case AF_INET:
891 return xfrm4_extract_output(x, skb);
892 case AF_INET6:
893 return xfrm6_extract_output(x, skb);
894 }
895
896 return -EAFNOSUPPORT;
897}
898
899void xfrm_local_error(struct sk_buff *skb, int mtu)
900{
901 unsigned int proto;
902 struct xfrm_state_afinfo *afinfo;
903
904 if (skb->protocol == htons(ETH_P_IP))
905 proto = AF_INET;
906 else if (skb->protocol == htons(ETH_P_IPV6) &&
907 skb->sk->sk_family == AF_INET6)
908 proto = AF_INET6;
909 else
910 return;
911
912 afinfo = xfrm_state_get_afinfo(proto);
913 if (afinfo) {
914 afinfo->local_error(skb, mtu);
915 rcu_read_unlock();
916 }
917}
918EXPORT_SYMBOL_GPL(xfrm_local_error);
1/*
2 * xfrm_output.c - Common IPsec encapsulation code.
3 *
4 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/errno.h>
13#include <linux/module.h>
14#include <linux/netdevice.h>
15#include <linux/netfilter.h>
16#include <linux/skbuff.h>
17#include <linux/slab.h>
18#include <linux/spinlock.h>
19#include <net/dst.h>
20#include <net/xfrm.h>
21
22static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
23
24static int xfrm_skb_check_space(struct sk_buff *skb)
25{
26 struct dst_entry *dst = skb_dst(skb);
27 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
28 - skb_headroom(skb);
29 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
30
31 if (nhead <= 0) {
32 if (ntail <= 0)
33 return 0;
34 nhead = 0;
35 } else if (ntail < 0)
36 ntail = 0;
37
38 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
39}
40
41/* Children define the path of the packet through the
42 * Linux networking. Thus, destinations are stackable.
43 */
44
45static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
46{
47 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
48
49 skb_dst_drop(skb);
50 return child;
51}
52
53static int xfrm_output_one(struct sk_buff *skb, int err)
54{
55 struct dst_entry *dst = skb_dst(skb);
56 struct xfrm_state *x = dst->xfrm;
57 struct net *net = xs_net(x);
58
59 if (err <= 0)
60 goto resume;
61
62 do {
63 err = xfrm_skb_check_space(skb);
64 if (err) {
65 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
66 goto error_nolock;
67 }
68
69 err = x->outer_mode->output(x, skb);
70 if (err) {
71 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
72 goto error_nolock;
73 }
74
75 spin_lock_bh(&x->lock);
76
77 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
78 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
79 err = -EINVAL;
80 goto error;
81 }
82
83 err = xfrm_state_check_expire(x);
84 if (err) {
85 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
86 goto error;
87 }
88
89 err = x->repl->overflow(x, skb);
90 if (err) {
91 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
92 goto error;
93 }
94
95 x->curlft.bytes += skb->len;
96 x->curlft.packets++;
97
98 spin_unlock_bh(&x->lock);
99
100 skb_dst_force(skb);
101
102 /* Inner headers are invalid now. */
103 skb->encapsulation = 0;
104
105 err = x->type->output(x, skb);
106 if (err == -EINPROGRESS)
107 goto out;
108
109resume:
110 if (err) {
111 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
112 goto error_nolock;
113 }
114
115 dst = skb_dst_pop(skb);
116 if (!dst) {
117 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
118 err = -EHOSTUNREACH;
119 goto error_nolock;
120 }
121 skb_dst_set(skb, dst);
122 x = dst->xfrm;
123 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
124
125 return 0;
126
127error:
128 spin_unlock_bh(&x->lock);
129error_nolock:
130 kfree_skb(skb);
131out:
132 return err;
133}
134
135int xfrm_output_resume(struct sk_buff *skb, int err)
136{
137 struct net *net = xs_net(skb_dst(skb)->xfrm);
138
139 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
140 nf_reset(skb);
141
142 err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
143 if (unlikely(err != 1))
144 goto out;
145
146 if (!skb_dst(skb)->xfrm)
147 return dst_output(net, skb->sk, skb);
148
149 err = nf_hook(skb_dst(skb)->ops->family,
150 NF_INET_POST_ROUTING, net, skb->sk, skb,
151 NULL, skb_dst(skb)->dev, xfrm_output2);
152 if (unlikely(err != 1))
153 goto out;
154 }
155
156 if (err == -EINPROGRESS)
157 err = 0;
158
159out:
160 return err;
161}
162EXPORT_SYMBOL_GPL(xfrm_output_resume);
163
164static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
165{
166 return xfrm_output_resume(skb, 1);
167}
168
169static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
170{
171 struct sk_buff *segs;
172
173 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
174 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_SGO_CB_OFFSET);
175 segs = skb_gso_segment(skb, 0);
176 kfree_skb(skb);
177 if (IS_ERR(segs))
178 return PTR_ERR(segs);
179 if (segs == NULL)
180 return -EINVAL;
181
182 do {
183 struct sk_buff *nskb = segs->next;
184 int err;
185
186 segs->next = NULL;
187 err = xfrm_output2(net, sk, segs);
188
189 if (unlikely(err)) {
190 kfree_skb_list(nskb);
191 return err;
192 }
193
194 segs = nskb;
195 } while (segs);
196
197 return 0;
198}
199
200int xfrm_output(struct sock *sk, struct sk_buff *skb)
201{
202 struct net *net = dev_net(skb_dst(skb)->dev);
203 int err;
204
205 if (skb_is_gso(skb))
206 return xfrm_output_gso(net, sk, skb);
207
208 if (skb->ip_summed == CHECKSUM_PARTIAL) {
209 err = skb_checksum_help(skb);
210 if (err) {
211 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
212 kfree_skb(skb);
213 return err;
214 }
215 }
216
217 return xfrm_output2(net, sk, skb);
218}
219EXPORT_SYMBOL_GPL(xfrm_output);
220
221int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
222{
223 struct xfrm_mode *inner_mode;
224 if (x->sel.family == AF_UNSPEC)
225 inner_mode = xfrm_ip2inner_mode(x,
226 xfrm_af2proto(skb_dst(skb)->ops->family));
227 else
228 inner_mode = x->inner_mode;
229
230 if (inner_mode == NULL)
231 return -EAFNOSUPPORT;
232 return inner_mode->afinfo->extract_output(x, skb);
233}
234EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
235
236void xfrm_local_error(struct sk_buff *skb, int mtu)
237{
238 unsigned int proto;
239 struct xfrm_state_afinfo *afinfo;
240
241 if (skb->protocol == htons(ETH_P_IP))
242 proto = AF_INET;
243 else if (skb->protocol == htons(ETH_P_IPV6))
244 proto = AF_INET6;
245 else
246 return;
247
248 afinfo = xfrm_state_get_afinfo(proto);
249 if (!afinfo)
250 return;
251
252 afinfo->local_error(skb, mtu);
253 xfrm_state_put_afinfo(afinfo);
254}
255EXPORT_SYMBOL_GPL(xfrm_local_error);