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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/* Add encapsulation header.
81 *
82 * The IP header and mutable extension headers will be moved forward to make
83 * space for the encapsulation header.
84 */
85static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
86{
87#if IS_ENABLED(CONFIG_IPV6)
88 struct ipv6hdr *iph;
89 u8 *prevhdr;
90 int hdr_len;
91
92 iph = ipv6_hdr(skb);
93 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
94
95 hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
96 if (hdr_len < 0)
97 return hdr_len;
98 skb_set_mac_header(skb,
99 (prevhdr - x->props.header_len) - skb->data);
100 skb_set_network_header(skb, -x->props.header_len);
101 skb->transport_header = skb->network_header + hdr_len;
102 __skb_pull(skb, hdr_len);
103 memmove(ipv6_hdr(skb), iph, hdr_len);
104 return 0;
105#else
106 WARN_ON_ONCE(1);
107 return -EAFNOSUPPORT;
108#endif
109}
110
111/* Add route optimization header space.
112 *
113 * The IP header and mutable extension headers will be moved forward to make
114 * space for the route optimization header.
115 */
116static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
117{
118#if IS_ENABLED(CONFIG_IPV6)
119 struct ipv6hdr *iph;
120 u8 *prevhdr;
121 int hdr_len;
122
123 iph = ipv6_hdr(skb);
124
125 hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
126 if (hdr_len < 0)
127 return hdr_len;
128 skb_set_mac_header(skb,
129 (prevhdr - x->props.header_len) - skb->data);
130 skb_set_network_header(skb, -x->props.header_len);
131 skb->transport_header = skb->network_header + hdr_len;
132 __skb_pull(skb, hdr_len);
133 memmove(ipv6_hdr(skb), iph, hdr_len);
134
135 x->lastused = ktime_get_real_seconds();
136
137 return 0;
138#else
139 WARN_ON_ONCE(1);
140 return -EAFNOSUPPORT;
141#endif
142}
143
144/* Add encapsulation header.
145 *
146 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
147 */
148static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
149{
150 struct ip_beet_phdr *ph;
151 struct iphdr *top_iph;
152 int hdrlen, optlen;
153
154 hdrlen = 0;
155 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
156 if (unlikely(optlen))
157 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
158
159 skb_set_network_header(skb, -x->props.header_len - hdrlen +
160 (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
161 if (x->sel.family != AF_INET6)
162 skb->network_header += IPV4_BEET_PHMAXLEN;
163 skb->mac_header = skb->network_header +
164 offsetof(struct iphdr, protocol);
165 skb->transport_header = skb->network_header + sizeof(*top_iph);
166
167 xfrm4_beet_make_header(skb);
168
169 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
170
171 top_iph = ip_hdr(skb);
172
173 if (unlikely(optlen)) {
174 if (WARN_ON(optlen < 0))
175 return -EINVAL;
176
177 ph->padlen = 4 - (optlen & 4);
178 ph->hdrlen = optlen / 8;
179 ph->nexthdr = top_iph->protocol;
180 if (ph->padlen)
181 memset(ph + 1, IPOPT_NOP, ph->padlen);
182
183 top_iph->protocol = IPPROTO_BEETPH;
184 top_iph->ihl = sizeof(struct iphdr) / 4;
185 }
186
187 top_iph->saddr = x->props.saddr.a4;
188 top_iph->daddr = x->id.daddr.a4;
189
190 return 0;
191}
192
193/* Add encapsulation header.
194 *
195 * The top IP header will be constructed per RFC 2401.
196 */
197static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
198{
199 struct dst_entry *dst = skb_dst(skb);
200 struct iphdr *top_iph;
201 int flags;
202
203 skb_set_inner_network_header(skb, skb_network_offset(skb));
204 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
205
206 skb_set_network_header(skb, -x->props.header_len);
207 skb->mac_header = skb->network_header +
208 offsetof(struct iphdr, protocol);
209 skb->transport_header = skb->network_header + sizeof(*top_iph);
210 top_iph = ip_hdr(skb);
211
212 top_iph->ihl = 5;
213 top_iph->version = 4;
214
215 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
216
217 /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
218 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
219 top_iph->tos = 0;
220 else
221 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
222 top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
223 XFRM_MODE_SKB_CB(skb)->tos);
224
225 flags = x->props.flags;
226 if (flags & XFRM_STATE_NOECN)
227 IP_ECN_clear(top_iph);
228
229 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
230 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
231
232 top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
233
234 top_iph->saddr = x->props.saddr.a4;
235 top_iph->daddr = x->id.daddr.a4;
236 ip_select_ident(dev_net(dst->dev), skb, NULL);
237
238 return 0;
239}
240
241#if IS_ENABLED(CONFIG_IPV6)
242static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
243{
244 struct dst_entry *dst = skb_dst(skb);
245 struct ipv6hdr *top_iph;
246 int dsfield;
247
248 skb_set_inner_network_header(skb, skb_network_offset(skb));
249 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
250
251 skb_set_network_header(skb, -x->props.header_len);
252 skb->mac_header = skb->network_header +
253 offsetof(struct ipv6hdr, nexthdr);
254 skb->transport_header = skb->network_header + sizeof(*top_iph);
255 top_iph = ipv6_hdr(skb);
256
257 top_iph->version = 6;
258
259 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
260 sizeof(top_iph->flow_lbl));
261 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
262
263 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
264 dsfield = 0;
265 else
266 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
267 dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
268 if (x->props.flags & XFRM_STATE_NOECN)
269 dsfield &= ~INET_ECN_MASK;
270 ipv6_change_dsfield(top_iph, 0, dsfield);
271 top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
272 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
273 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
274 return 0;
275}
276
277static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
278{
279 struct ipv6hdr *top_iph;
280 struct ip_beet_phdr *ph;
281 int optlen, hdr_len;
282
283 hdr_len = 0;
284 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
285 if (unlikely(optlen))
286 hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
287
288 skb_set_network_header(skb, -x->props.header_len - hdr_len);
289 if (x->sel.family != AF_INET6)
290 skb->network_header += IPV4_BEET_PHMAXLEN;
291 skb->mac_header = skb->network_header +
292 offsetof(struct ipv6hdr, nexthdr);
293 skb->transport_header = skb->network_header + sizeof(*top_iph);
294 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
295
296 xfrm6_beet_make_header(skb);
297
298 top_iph = ipv6_hdr(skb);
299 if (unlikely(optlen)) {
300 if (WARN_ON(optlen < 0))
301 return -EINVAL;
302
303 ph->padlen = 4 - (optlen & 4);
304 ph->hdrlen = optlen / 8;
305 ph->nexthdr = top_iph->nexthdr;
306 if (ph->padlen)
307 memset(ph + 1, IPOPT_NOP, ph->padlen);
308
309 top_iph->nexthdr = IPPROTO_BEETPH;
310 }
311
312 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
313 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
314 return 0;
315}
316#endif
317
318/* Add encapsulation header.
319 *
320 * On exit, the transport header will be set to the start of the
321 * encapsulation header to be filled in by x->type->output and the mac
322 * header will be set to the nextheader (protocol for IPv4) field of the
323 * extension header directly preceding the encapsulation header, or in
324 * its absence, that of the top IP header.
325 * The value of the network header will always point to the top IP header
326 * while skb->data will point to the payload.
327 */
328static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
329{
330 int err;
331
332 err = xfrm_inner_extract_output(x, skb);
333 if (err)
334 return err;
335
336 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
337 skb->protocol = htons(ETH_P_IP);
338
339 switch (x->outer_mode.encap) {
340 case XFRM_MODE_BEET:
341 return xfrm4_beet_encap_add(x, skb);
342 case XFRM_MODE_TUNNEL:
343 return xfrm4_tunnel_encap_add(x, skb);
344 }
345
346 WARN_ON_ONCE(1);
347 return -EOPNOTSUPP;
348}
349
350static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
351{
352#if IS_ENABLED(CONFIG_IPV6)
353 int err;
354
355 err = xfrm_inner_extract_output(x, skb);
356 if (err)
357 return err;
358
359 skb->ignore_df = 1;
360 skb->protocol = htons(ETH_P_IPV6);
361
362 switch (x->outer_mode.encap) {
363 case XFRM_MODE_BEET:
364 return xfrm6_beet_encap_add(x, skb);
365 case XFRM_MODE_TUNNEL:
366 return xfrm6_tunnel_encap_add(x, skb);
367 default:
368 WARN_ON_ONCE(1);
369 return -EOPNOTSUPP;
370 }
371#endif
372 WARN_ON_ONCE(1);
373 return -EAFNOSUPPORT;
374}
375
376static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
377{
378 switch (x->outer_mode.encap) {
379 case XFRM_MODE_BEET:
380 case XFRM_MODE_TUNNEL:
381 if (x->outer_mode.family == AF_INET)
382 return xfrm4_prepare_output(x, skb);
383 if (x->outer_mode.family == AF_INET6)
384 return xfrm6_prepare_output(x, skb);
385 break;
386 case XFRM_MODE_TRANSPORT:
387 if (x->outer_mode.family == AF_INET)
388 return xfrm4_transport_output(x, skb);
389 if (x->outer_mode.family == AF_INET6)
390 return xfrm6_transport_output(x, skb);
391 break;
392 case XFRM_MODE_ROUTEOPTIMIZATION:
393 if (x->outer_mode.family == AF_INET6)
394 return xfrm6_ro_output(x, skb);
395 WARN_ON_ONCE(1);
396 break;
397 default:
398 WARN_ON_ONCE(1);
399 break;
400 }
401
402 return -EOPNOTSUPP;
403}
404
405#if IS_ENABLED(CONFIG_NET_PKTGEN)
406int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
407{
408 return xfrm_outer_mode_output(x, skb);
409}
410EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
411#endif
412
413static int xfrm_output_one(struct sk_buff *skb, int err)
414{
415 struct dst_entry *dst = skb_dst(skb);
416 struct xfrm_state *x = dst->xfrm;
417 struct net *net = xs_net(x);
418
419 if (err <= 0)
420 goto resume;
421
422 do {
423 err = xfrm_skb_check_space(skb);
424 if (err) {
425 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
426 goto error_nolock;
427 }
428
429 skb->mark = xfrm_smark_get(skb->mark, x);
430
431 err = xfrm_outer_mode_output(x, skb);
432 if (err) {
433 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
434 goto error_nolock;
435 }
436
437 spin_lock_bh(&x->lock);
438
439 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
440 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
441 err = -EINVAL;
442 goto error;
443 }
444
445 err = xfrm_state_check_expire(x);
446 if (err) {
447 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
448 goto error;
449 }
450
451 err = x->repl->overflow(x, skb);
452 if (err) {
453 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
454 goto error;
455 }
456
457 x->curlft.bytes += skb->len;
458 x->curlft.packets++;
459
460 spin_unlock_bh(&x->lock);
461
462 skb_dst_force(skb);
463 if (!skb_dst(skb)) {
464 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
465 err = -EHOSTUNREACH;
466 goto error_nolock;
467 }
468
469 if (xfrm_offload(skb)) {
470 x->type_offload->encap(x, skb);
471 } else {
472 /* Inner headers are invalid now. */
473 skb->encapsulation = 0;
474
475 err = x->type->output(x, skb);
476 if (err == -EINPROGRESS)
477 goto out;
478 }
479
480resume:
481 if (err) {
482 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
483 goto error_nolock;
484 }
485
486 dst = skb_dst_pop(skb);
487 if (!dst) {
488 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
489 err = -EHOSTUNREACH;
490 goto error_nolock;
491 }
492 skb_dst_set(skb, dst);
493 x = dst->xfrm;
494 } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
495
496 return 0;
497
498error:
499 spin_unlock_bh(&x->lock);
500error_nolock:
501 kfree_skb(skb);
502out:
503 return err;
504}
505
506int xfrm_output_resume(struct sk_buff *skb, int err)
507{
508 struct net *net = xs_net(skb_dst(skb)->xfrm);
509
510 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
511 nf_reset_ct(skb);
512
513 err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
514 if (unlikely(err != 1))
515 goto out;
516
517 if (!skb_dst(skb)->xfrm)
518 return dst_output(net, skb->sk, skb);
519
520 err = nf_hook(skb_dst(skb)->ops->family,
521 NF_INET_POST_ROUTING, net, skb->sk, skb,
522 NULL, skb_dst(skb)->dev, xfrm_output2);
523 if (unlikely(err != 1))
524 goto out;
525 }
526
527 if (err == -EINPROGRESS)
528 err = 0;
529
530out:
531 return err;
532}
533EXPORT_SYMBOL_GPL(xfrm_output_resume);
534
535static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
536{
537 return xfrm_output_resume(skb, 1);
538}
539
540static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
541{
542 struct sk_buff *segs, *nskb;
543
544 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
545 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
546 segs = skb_gso_segment(skb, 0);
547 kfree_skb(skb);
548 if (IS_ERR(segs))
549 return PTR_ERR(segs);
550 if (segs == NULL)
551 return -EINVAL;
552
553 skb_list_walk_safe(segs, segs, nskb) {
554 int err;
555
556 skb_mark_not_on_list(segs);
557 err = xfrm_output2(net, sk, segs);
558
559 if (unlikely(err)) {
560 kfree_skb_list(nskb);
561 return err;
562 }
563 }
564
565 return 0;
566}
567
568int xfrm_output(struct sock *sk, struct sk_buff *skb)
569{
570 struct net *net = dev_net(skb_dst(skb)->dev);
571 struct xfrm_state *x = skb_dst(skb)->xfrm;
572 int err;
573
574 switch (x->outer_mode.family) {
575 case AF_INET:
576 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
577 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
578 break;
579 case AF_INET6:
580 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
581
582 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
583 break;
584 }
585
586 secpath_reset(skb);
587
588 if (xfrm_dev_offload_ok(skb, x)) {
589 struct sec_path *sp;
590
591 sp = secpath_set(skb);
592 if (!sp) {
593 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
594 kfree_skb(skb);
595 return -ENOMEM;
596 }
597 skb->encapsulation = 1;
598
599 sp->olen++;
600 sp->xvec[sp->len++] = x;
601 xfrm_state_hold(x);
602
603 if (skb_is_gso(skb)) {
604 if (skb->inner_protocol)
605 return xfrm_output_gso(net, sk, skb);
606
607 skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
608 goto out;
609 }
610
611 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
612 goto out;
613 } else {
614 if (skb_is_gso(skb))
615 return xfrm_output_gso(net, sk, skb);
616 }
617
618 if (skb->ip_summed == CHECKSUM_PARTIAL) {
619 err = skb_checksum_help(skb);
620 if (err) {
621 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
622 kfree_skb(skb);
623 return err;
624 }
625 }
626
627out:
628 return xfrm_output2(net, sk, skb);
629}
630EXPORT_SYMBOL_GPL(xfrm_output);
631
632static int xfrm4_tunnel_check_size(struct sk_buff *skb)
633{
634 int mtu, ret = 0;
635
636 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
637 goto out;
638
639 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
640 goto out;
641
642 mtu = dst_mtu(skb_dst(skb));
643 if ((!skb_is_gso(skb) && skb->len > mtu) ||
644 (skb_is_gso(skb) &&
645 !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
646 skb->protocol = htons(ETH_P_IP);
647
648 if (skb->sk)
649 xfrm_local_error(skb, mtu);
650 else
651 icmp_send(skb, ICMP_DEST_UNREACH,
652 ICMP_FRAG_NEEDED, htonl(mtu));
653 ret = -EMSGSIZE;
654 }
655out:
656 return ret;
657}
658
659static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
660{
661 int err;
662
663 err = xfrm4_tunnel_check_size(skb);
664 if (err)
665 return err;
666
667 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
668
669 xfrm4_extract_header(skb);
670 return 0;
671}
672
673#if IS_ENABLED(CONFIG_IPV6)
674static int xfrm6_tunnel_check_size(struct sk_buff *skb)
675{
676 int mtu, ret = 0;
677 struct dst_entry *dst = skb_dst(skb);
678
679 if (skb->ignore_df)
680 goto out;
681
682 mtu = dst_mtu(dst);
683 if (mtu < IPV6_MIN_MTU)
684 mtu = IPV6_MIN_MTU;
685
686 if ((!skb_is_gso(skb) && skb->len > mtu) ||
687 (skb_is_gso(skb) &&
688 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
689 skb->dev = dst->dev;
690 skb->protocol = htons(ETH_P_IPV6);
691
692 if (xfrm6_local_dontfrag(skb->sk))
693 ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
694 else if (skb->sk)
695 xfrm_local_error(skb, mtu);
696 else
697 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
698 ret = -EMSGSIZE;
699 }
700out:
701 return ret;
702}
703#endif
704
705static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
706{
707#if IS_ENABLED(CONFIG_IPV6)
708 int err;
709
710 err = xfrm6_tunnel_check_size(skb);
711 if (err)
712 return err;
713
714 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
715
716 xfrm6_extract_header(skb);
717 return 0;
718#else
719 WARN_ON_ONCE(1);
720 return -EAFNOSUPPORT;
721#endif
722}
723
724static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
725{
726 const struct xfrm_mode *inner_mode;
727
728 if (x->sel.family == AF_UNSPEC)
729 inner_mode = xfrm_ip2inner_mode(x,
730 xfrm_af2proto(skb_dst(skb)->ops->family));
731 else
732 inner_mode = &x->inner_mode;
733
734 if (inner_mode == NULL)
735 return -EAFNOSUPPORT;
736
737 switch (inner_mode->family) {
738 case AF_INET:
739 return xfrm4_extract_output(x, skb);
740 case AF_INET6:
741 return xfrm6_extract_output(x, skb);
742 }
743
744 return -EAFNOSUPPORT;
745}
746
747void xfrm_local_error(struct sk_buff *skb, int mtu)
748{
749 unsigned int proto;
750 struct xfrm_state_afinfo *afinfo;
751
752 if (skb->protocol == htons(ETH_P_IP))
753 proto = AF_INET;
754 else if (skb->protocol == htons(ETH_P_IPV6) &&
755 skb->sk->sk_family == AF_INET6)
756 proto = AF_INET6;
757 else
758 return;
759
760 afinfo = xfrm_state_get_afinfo(proto);
761 if (afinfo) {
762 afinfo->local_error(skb, mtu);
763 rcu_read_unlock();
764 }
765}
766EXPORT_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);