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/gso.h>
17 #include <net/icmp.h>
18 #include <net/inet_ecn.h>
19 #include <net/xfrm.h>
20
21 #if IS_ENABLED(CONFIG_IPV6)
22 #include <net/ip6_route.h>
23 #include <net/ipv6_stubs.h>
24 #endif
25
26 #include "xfrm_inout.h"
27
28 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
29 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
30
xfrm_skb_check_space(struct sk_buff * skb)31 static int xfrm_skb_check_space(struct sk_buff *skb)
32 {
33 struct dst_entry *dst = skb_dst(skb);
34 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
35 - skb_headroom(skb);
36 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
37
38 if (nhead <= 0) {
39 if (ntail <= 0)
40 return 0;
41 nhead = 0;
42 } else if (ntail < 0)
43 ntail = 0;
44
45 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
46 }
47
48 /* Children define the path of the packet through the
49 * Linux networking. Thus, destinations are stackable.
50 */
51
skb_dst_pop(struct sk_buff * skb)52 static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
53 {
54 struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
55
56 skb_dst_drop(skb);
57 return child;
58 }
59
60 /* Add encapsulation header.
61 *
62 * The IP header will be moved forward to make space for the encapsulation
63 * header.
64 */
xfrm4_transport_output(struct xfrm_state * x,struct sk_buff * skb)65 static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
66 {
67 struct iphdr *iph = ip_hdr(skb);
68 int ihl = iph->ihl * 4;
69
70 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
71
72 skb_set_network_header(skb, -x->props.header_len);
73 skb->mac_header = skb->network_header +
74 offsetof(struct iphdr, protocol);
75 skb->transport_header = skb->network_header + ihl;
76 __skb_pull(skb, ihl);
77 memmove(skb_network_header(skb), iph, ihl);
78 return 0;
79 }
80
81 #if IS_ENABLED(CONFIG_IPV6_MIP6)
mip6_rthdr_offset(struct sk_buff * skb,u8 ** nexthdr,int type)82 static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
83 {
84 const unsigned char *nh = skb_network_header(skb);
85 unsigned int offset = sizeof(struct ipv6hdr);
86 unsigned int packet_len;
87 int found_rhdr = 0;
88
89 packet_len = skb_tail_pointer(skb) - nh;
90 *nexthdr = &ipv6_hdr(skb)->nexthdr;
91
92 while (offset <= packet_len) {
93 struct ipv6_opt_hdr *exthdr;
94
95 switch (**nexthdr) {
96 case NEXTHDR_HOP:
97 break;
98 case NEXTHDR_ROUTING:
99 if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
100 struct ipv6_rt_hdr *rt;
101
102 rt = (struct ipv6_rt_hdr *)(nh + offset);
103 if (rt->type != 0)
104 return offset;
105 }
106 found_rhdr = 1;
107 break;
108 case NEXTHDR_DEST:
109 /* HAO MUST NOT appear more than once.
110 * XXX: It is better to try to find by the end of
111 * XXX: packet if HAO exists.
112 */
113 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
114 net_dbg_ratelimited("mip6: hao exists already, override\n");
115 return offset;
116 }
117
118 if (found_rhdr)
119 return offset;
120
121 break;
122 default:
123 return offset;
124 }
125
126 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
127 return -EINVAL;
128
129 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
130 offset);
131 offset += ipv6_optlen(exthdr);
132 if (offset > IPV6_MAXPLEN)
133 return -EINVAL;
134 *nexthdr = &exthdr->nexthdr;
135 }
136
137 return -EINVAL;
138 }
139 #endif
140
141 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_hdr_offset(struct xfrm_state * x,struct sk_buff * skb,u8 ** prevhdr)142 static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
143 {
144 switch (x->type->proto) {
145 #if IS_ENABLED(CONFIG_IPV6_MIP6)
146 case IPPROTO_DSTOPTS:
147 case IPPROTO_ROUTING:
148 return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
149 #endif
150 default:
151 break;
152 }
153
154 return ip6_find_1stfragopt(skb, prevhdr);
155 }
156 #endif
157
158 /* Add encapsulation header.
159 *
160 * The IP header and mutable extension headers will be moved forward to make
161 * space for the encapsulation header.
162 */
xfrm6_transport_output(struct xfrm_state * x,struct sk_buff * skb)163 static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
164 {
165 #if IS_ENABLED(CONFIG_IPV6)
166 struct ipv6hdr *iph;
167 u8 *prevhdr;
168 int hdr_len;
169
170 iph = ipv6_hdr(skb);
171 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
172
173 hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
174 if (hdr_len < 0)
175 return hdr_len;
176 skb_set_mac_header(skb,
177 (prevhdr - x->props.header_len) - skb->data);
178 skb_set_network_header(skb, -x->props.header_len);
179 skb->transport_header = skb->network_header + hdr_len;
180 __skb_pull(skb, hdr_len);
181 memmove(ipv6_hdr(skb), iph, hdr_len);
182 return 0;
183 #else
184 WARN_ON_ONCE(1);
185 return -EAFNOSUPPORT;
186 #endif
187 }
188
189 /* Add route optimization header space.
190 *
191 * The IP header and mutable extension headers will be moved forward to make
192 * space for the route optimization header.
193 */
xfrm6_ro_output(struct xfrm_state * x,struct sk_buff * skb)194 static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
195 {
196 #if IS_ENABLED(CONFIG_IPV6)
197 struct ipv6hdr *iph;
198 u8 *prevhdr;
199 int hdr_len;
200
201 iph = ipv6_hdr(skb);
202
203 hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
204 if (hdr_len < 0)
205 return hdr_len;
206 skb_set_mac_header(skb,
207 (prevhdr - x->props.header_len) - skb->data);
208 skb_set_network_header(skb, -x->props.header_len);
209 skb->transport_header = skb->network_header + hdr_len;
210 __skb_pull(skb, hdr_len);
211 memmove(ipv6_hdr(skb), iph, hdr_len);
212
213 return 0;
214 #else
215 WARN_ON_ONCE(1);
216 return -EAFNOSUPPORT;
217 #endif
218 }
219
220 /* Add encapsulation header.
221 *
222 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
223 */
xfrm4_beet_encap_add(struct xfrm_state * x,struct sk_buff * skb)224 static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
225 {
226 struct ip_beet_phdr *ph;
227 struct iphdr *top_iph;
228 int hdrlen, optlen;
229
230 hdrlen = 0;
231 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
232 if (unlikely(optlen))
233 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
234
235 skb_set_network_header(skb, -x->props.header_len - hdrlen +
236 (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
237 if (x->sel.family != AF_INET6)
238 skb->network_header += IPV4_BEET_PHMAXLEN;
239 skb->mac_header = skb->network_header +
240 offsetof(struct iphdr, protocol);
241 skb->transport_header = skb->network_header + sizeof(*top_iph);
242
243 xfrm4_beet_make_header(skb);
244
245 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
246
247 top_iph = ip_hdr(skb);
248
249 if (unlikely(optlen)) {
250 if (WARN_ON(optlen < 0))
251 return -EINVAL;
252
253 ph->padlen = 4 - (optlen & 4);
254 ph->hdrlen = optlen / 8;
255 ph->nexthdr = top_iph->protocol;
256 if (ph->padlen)
257 memset(ph + 1, IPOPT_NOP, ph->padlen);
258
259 top_iph->protocol = IPPROTO_BEETPH;
260 top_iph->ihl = sizeof(struct iphdr) / 4;
261 }
262
263 top_iph->saddr = x->props.saddr.a4;
264 top_iph->daddr = x->id.daddr.a4;
265
266 return 0;
267 }
268
269 /* Add encapsulation header.
270 *
271 * The top IP header will be constructed per RFC 2401.
272 */
xfrm4_tunnel_encap_add(struct xfrm_state * x,struct sk_buff * skb)273 static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
274 {
275 bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
276 struct dst_entry *dst = skb_dst(skb);
277 struct iphdr *top_iph;
278 int flags;
279
280 skb_set_inner_network_header(skb, skb_network_offset(skb));
281 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
282
283 skb_set_network_header(skb, -x->props.header_len);
284 skb->mac_header = skb->network_header +
285 offsetof(struct iphdr, protocol);
286 skb->transport_header = skb->network_header + sizeof(*top_iph);
287 top_iph = ip_hdr(skb);
288
289 top_iph->ihl = 5;
290 top_iph->version = 4;
291
292 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
293
294 /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
295 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
296 top_iph->tos = 0;
297 else
298 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
299 top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
300 XFRM_MODE_SKB_CB(skb)->tos);
301
302 flags = x->props.flags;
303 if (flags & XFRM_STATE_NOECN)
304 IP_ECN_clear(top_iph);
305
306 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
307 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
308
309 top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
310
311 top_iph->saddr = x->props.saddr.a4;
312 top_iph->daddr = x->id.daddr.a4;
313 ip_select_ident(dev_net(dst->dev), skb, NULL);
314
315 return 0;
316 }
317
318 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_tunnel_encap_add(struct xfrm_state * x,struct sk_buff * skb)319 static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
320 {
321 struct dst_entry *dst = skb_dst(skb);
322 struct ipv6hdr *top_iph;
323 int dsfield;
324
325 skb_set_inner_network_header(skb, skb_network_offset(skb));
326 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
327
328 skb_set_network_header(skb, -x->props.header_len);
329 skb->mac_header = skb->network_header +
330 offsetof(struct ipv6hdr, nexthdr);
331 skb->transport_header = skb->network_header + sizeof(*top_iph);
332 top_iph = ipv6_hdr(skb);
333
334 top_iph->version = 6;
335
336 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
337 sizeof(top_iph->flow_lbl));
338 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
339
340 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
341 dsfield = 0;
342 else
343 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
344 dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
345 if (x->props.flags & XFRM_STATE_NOECN)
346 dsfield &= ~INET_ECN_MASK;
347 ipv6_change_dsfield(top_iph, 0, dsfield);
348 top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
349 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
350 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
351 return 0;
352 }
353
xfrm6_beet_encap_add(struct xfrm_state * x,struct sk_buff * skb)354 static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
355 {
356 struct ipv6hdr *top_iph;
357 struct ip_beet_phdr *ph;
358 int optlen, hdr_len;
359
360 hdr_len = 0;
361 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
362 if (unlikely(optlen))
363 hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
364
365 skb_set_network_header(skb, -x->props.header_len - hdr_len);
366 if (x->sel.family != AF_INET6)
367 skb->network_header += IPV4_BEET_PHMAXLEN;
368 skb->mac_header = skb->network_header +
369 offsetof(struct ipv6hdr, nexthdr);
370 skb->transport_header = skb->network_header + sizeof(*top_iph);
371 ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
372
373 xfrm6_beet_make_header(skb);
374
375 top_iph = ipv6_hdr(skb);
376 if (unlikely(optlen)) {
377 if (WARN_ON(optlen < 0))
378 return -EINVAL;
379
380 ph->padlen = 4 - (optlen & 4);
381 ph->hdrlen = optlen / 8;
382 ph->nexthdr = top_iph->nexthdr;
383 if (ph->padlen)
384 memset(ph + 1, IPOPT_NOP, ph->padlen);
385
386 top_iph->nexthdr = IPPROTO_BEETPH;
387 }
388
389 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
390 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
391 return 0;
392 }
393 #endif
394
395 /* Add encapsulation header.
396 *
397 * On exit, the transport header will be set to the start of the
398 * encapsulation header to be filled in by x->type->output and the mac
399 * header will be set to the nextheader (protocol for IPv4) field of the
400 * extension header directly preceding the encapsulation header, or in
401 * its absence, that of the top IP header.
402 * The value of the network header will always point to the top IP header
403 * while skb->data will point to the payload.
404 */
xfrm4_prepare_output(struct xfrm_state * x,struct sk_buff * skb)405 static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
406 {
407 int err;
408
409 err = xfrm_inner_extract_output(x, skb);
410 if (err)
411 return err;
412
413 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
414 skb->protocol = htons(ETH_P_IP);
415
416 switch (x->props.mode) {
417 case XFRM_MODE_BEET:
418 return xfrm4_beet_encap_add(x, skb);
419 case XFRM_MODE_TUNNEL:
420 return xfrm4_tunnel_encap_add(x, skb);
421 }
422
423 WARN_ON_ONCE(1);
424 return -EOPNOTSUPP;
425 }
426
xfrm6_prepare_output(struct xfrm_state * x,struct sk_buff * skb)427 static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
428 {
429 #if IS_ENABLED(CONFIG_IPV6)
430 int err;
431
432 err = xfrm_inner_extract_output(x, skb);
433 if (err)
434 return err;
435
436 skb->ignore_df = 1;
437 skb->protocol = htons(ETH_P_IPV6);
438
439 switch (x->props.mode) {
440 case XFRM_MODE_BEET:
441 return xfrm6_beet_encap_add(x, skb);
442 case XFRM_MODE_TUNNEL:
443 return xfrm6_tunnel_encap_add(x, skb);
444 default:
445 WARN_ON_ONCE(1);
446 return -EOPNOTSUPP;
447 }
448 #endif
449 WARN_ON_ONCE(1);
450 return -EAFNOSUPPORT;
451 }
452
xfrm_outer_mode_output(struct xfrm_state * x,struct sk_buff * skb)453 static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
454 {
455 switch (x->props.mode) {
456 case XFRM_MODE_BEET:
457 case XFRM_MODE_TUNNEL:
458 if (x->props.family == AF_INET)
459 return xfrm4_prepare_output(x, skb);
460 if (x->props.family == AF_INET6)
461 return xfrm6_prepare_output(x, skb);
462 break;
463 case XFRM_MODE_TRANSPORT:
464 if (x->props.family == AF_INET)
465 return xfrm4_transport_output(x, skb);
466 if (x->props.family == AF_INET6)
467 return xfrm6_transport_output(x, skb);
468 break;
469 case XFRM_MODE_ROUTEOPTIMIZATION:
470 if (x->props.family == AF_INET6)
471 return xfrm6_ro_output(x, skb);
472 WARN_ON_ONCE(1);
473 break;
474 default:
475 if (x->mode_cbs && x->mode_cbs->prepare_output)
476 return x->mode_cbs->prepare_output(x, skb);
477 WARN_ON_ONCE(1);
478 break;
479 }
480
481 return -EOPNOTSUPP;
482 }
483
484 #if IS_ENABLED(CONFIG_NET_PKTGEN)
pktgen_xfrm_outer_mode_output(struct xfrm_state * x,struct sk_buff * skb)485 int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
486 {
487 return xfrm_outer_mode_output(x, skb);
488 }
489 EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
490 #endif
491
xfrm_output_one(struct sk_buff * skb,int err)492 static int xfrm_output_one(struct sk_buff *skb, int err)
493 {
494 struct dst_entry *dst = skb_dst(skb);
495 struct xfrm_state *x = dst->xfrm;
496 struct net *net = xs_net(x);
497
498 if (err <= 0 || x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
499 goto resume;
500
501 do {
502 err = xfrm_skb_check_space(skb);
503 if (err) {
504 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
505 goto error_nolock;
506 }
507
508 skb->mark = xfrm_smark_get(skb->mark, x);
509
510 err = xfrm_outer_mode_output(x, skb);
511 if (err) {
512 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
513 goto error_nolock;
514 }
515
516 spin_lock_bh(&x->lock);
517
518 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
519 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
520 err = -EINVAL;
521 goto error;
522 }
523
524 err = xfrm_state_check_expire(x);
525 if (err) {
526 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
527 goto error;
528 }
529
530 err = xfrm_replay_overflow(x, skb);
531 if (err) {
532 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
533 goto error;
534 }
535
536 x->curlft.bytes += skb->len;
537 x->curlft.packets++;
538 x->lastused = ktime_get_real_seconds();
539
540 spin_unlock_bh(&x->lock);
541
542 skb_dst_force(skb);
543 if (!skb_dst(skb)) {
544 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
545 err = -EHOSTUNREACH;
546 goto error_nolock;
547 }
548
549 if (xfrm_offload(skb)) {
550 x->type_offload->encap(x, skb);
551 } else {
552 /* Inner headers are invalid now. */
553 skb->encapsulation = 0;
554
555 err = x->type->output(x, skb);
556 if (err == -EINPROGRESS)
557 goto out;
558 }
559
560 resume:
561 if (err) {
562 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
563 goto error_nolock;
564 }
565
566 dst = skb_dst_pop(skb);
567 if (!dst) {
568 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
569 err = -EHOSTUNREACH;
570 goto error_nolock;
571 }
572 skb_dst_set(skb, dst);
573 x = dst->xfrm;
574 } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
575
576 return 0;
577
578 error:
579 spin_unlock_bh(&x->lock);
580 error_nolock:
581 kfree_skb(skb);
582 out:
583 return err;
584 }
585
xfrm_output_resume(struct sock * sk,struct sk_buff * skb,int err)586 int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
587 {
588 struct net *net = xs_net(skb_dst(skb)->xfrm);
589
590 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
591 nf_reset_ct(skb);
592
593 err = skb_dst(skb)->ops->local_out(net, sk, skb);
594 if (unlikely(err != 1))
595 goto out;
596
597 if (!skb_dst(skb)->xfrm)
598 return dst_output(net, sk, skb);
599
600 err = nf_hook(skb_dst(skb)->ops->family,
601 NF_INET_POST_ROUTING, net, sk, skb,
602 NULL, skb_dst(skb)->dev, xfrm_output2);
603 if (unlikely(err != 1))
604 goto out;
605 }
606
607 if (err == -EINPROGRESS)
608 err = 0;
609
610 out:
611 return err;
612 }
613 EXPORT_SYMBOL_GPL(xfrm_output_resume);
614
xfrm_output2(struct net * net,struct sock * sk,struct sk_buff * skb)615 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
616 {
617 return xfrm_output_resume(sk, skb, 1);
618 }
619
xfrm_output_gso(struct net * net,struct sock * sk,struct sk_buff * skb)620 static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
621 {
622 struct sk_buff *segs, *nskb;
623
624 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
625 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
626 segs = skb_gso_segment(skb, 0);
627 kfree_skb(skb);
628 if (IS_ERR(segs))
629 return PTR_ERR(segs);
630 if (segs == NULL)
631 return -EINVAL;
632
633 skb_list_walk_safe(segs, segs, nskb) {
634 int err;
635
636 skb_mark_not_on_list(segs);
637 err = xfrm_output2(net, sk, segs);
638
639 if (unlikely(err)) {
640 kfree_skb_list(nskb);
641 return err;
642 }
643 }
644
645 return 0;
646 }
647
648 /* For partial checksum offload, the outer header checksum is calculated
649 * by software and the inner header checksum is calculated by hardware.
650 * This requires hardware to know the inner packet type to calculate
651 * the inner header checksum. Save inner ip protocol here to avoid
652 * traversing the packet in the vendor's xmit code.
653 * For IPsec tunnel mode save the ip protocol from the IP header of the
654 * plain text packet. Otherwise If the encap type is IPIP, just save
655 * skb->inner_ipproto in any other case get the ip protocol from the IP
656 * header.
657 */
xfrm_get_inner_ipproto(struct sk_buff * skb,struct xfrm_state * x)658 static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
659 {
660 struct xfrm_offload *xo = xfrm_offload(skb);
661 const struct ethhdr *eth;
662
663 if (!xo)
664 return;
665
666 if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
667 switch (x->outer_mode.family) {
668 case AF_INET:
669 xo->inner_ipproto = ip_hdr(skb)->protocol;
670 break;
671 case AF_INET6:
672 xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
673 break;
674 default:
675 break;
676 }
677
678 return;
679 }
680 if (x->outer_mode.encap == XFRM_MODE_IPTFS) {
681 xo->inner_ipproto = IPPROTO_AGGFRAG;
682 return;
683 }
684
685 /* non-Tunnel Mode */
686 if (!skb->encapsulation)
687 return;
688
689 if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
690 xo->inner_ipproto = skb->inner_ipproto;
691 return;
692 }
693
694 if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
695 return;
696
697 eth = (struct ethhdr *)skb_inner_mac_header(skb);
698
699 switch (ntohs(eth->h_proto)) {
700 case ETH_P_IPV6:
701 xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
702 break;
703 case ETH_P_IP:
704 xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
705 break;
706 }
707 }
708
xfrm_output(struct sock * sk,struct sk_buff * skb)709 int xfrm_output(struct sock *sk, struct sk_buff *skb)
710 {
711 struct net *net = dev_net(skb_dst(skb)->dev);
712 struct xfrm_state *x = skb_dst(skb)->xfrm;
713 int family;
714 int err;
715
716 family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
717 : skb_dst(skb)->ops->family;
718
719 switch (family) {
720 case AF_INET:
721 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
722 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
723 break;
724 case AF_INET6:
725 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
726
727 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
728 break;
729 }
730
731 if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) {
732 if (!xfrm_dev_offload_ok(skb, x)) {
733 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
734 kfree_skb(skb);
735 return -EHOSTUNREACH;
736 }
737
738 return xfrm_output_resume(sk, skb, 0);
739 }
740
741 secpath_reset(skb);
742
743 if (xfrm_dev_offload_ok(skb, x)) {
744 struct sec_path *sp;
745
746 sp = secpath_set(skb);
747 if (!sp) {
748 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
749 kfree_skb(skb);
750 return -ENOMEM;
751 }
752
753 sp->olen++;
754 sp->xvec[sp->len++] = x;
755 xfrm_state_hold(x);
756
757 xfrm_get_inner_ipproto(skb, x);
758 skb->encapsulation = 1;
759
760 if (skb_is_gso(skb)) {
761 if (skb->inner_protocol)
762 return xfrm_output_gso(net, sk, skb);
763
764 skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
765 goto out;
766 }
767
768 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
769 goto out;
770 } else {
771 if (skb_is_gso(skb))
772 return xfrm_output_gso(net, sk, skb);
773 }
774
775 if (skb->ip_summed == CHECKSUM_PARTIAL) {
776 err = skb_checksum_help(skb);
777 if (err) {
778 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
779 kfree_skb(skb);
780 return err;
781 }
782 }
783
784 out:
785 return xfrm_output2(net, sk, skb);
786 }
787 EXPORT_SYMBOL_GPL(xfrm_output);
788
xfrm4_tunnel_check_size(struct sk_buff * skb)789 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
790 {
791 int mtu, ret = 0;
792
793 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
794 goto out;
795
796 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
797 goto out;
798
799 mtu = dst_mtu(skb_dst(skb));
800 if ((!skb_is_gso(skb) && skb->len > mtu) ||
801 (skb_is_gso(skb) &&
802 !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
803 skb->protocol = htons(ETH_P_IP);
804
805 if (skb->sk && sk_fullsock(skb->sk))
806 xfrm_local_error(skb, mtu);
807 else
808 icmp_send(skb, ICMP_DEST_UNREACH,
809 ICMP_FRAG_NEEDED, htonl(mtu));
810 ret = -EMSGSIZE;
811 }
812 out:
813 return ret;
814 }
815
xfrm4_extract_output(struct xfrm_state * x,struct sk_buff * skb)816 static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
817 {
818 int err;
819
820 if (x->outer_mode.encap == XFRM_MODE_BEET &&
821 ip_is_fragment(ip_hdr(skb))) {
822 net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
823 return -EAFNOSUPPORT;
824 }
825
826 err = xfrm4_tunnel_check_size(skb);
827 if (err)
828 return err;
829
830 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
831
832 xfrm4_extract_header(skb);
833 return 0;
834 }
835
836 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_tunnel_check_size(struct sk_buff * skb)837 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
838 {
839 int mtu, ret = 0;
840 struct dst_entry *dst = skb_dst(skb);
841 struct sock *sk = skb_to_full_sk(skb);
842
843 if (skb->ignore_df)
844 goto out;
845
846 mtu = dst_mtu(dst);
847 if (mtu < IPV6_MIN_MTU)
848 mtu = IPV6_MIN_MTU;
849
850 if ((!skb_is_gso(skb) && skb->len > mtu) ||
851 (skb_is_gso(skb) &&
852 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
853 skb->dev = dst->dev;
854 skb->protocol = htons(ETH_P_IPV6);
855
856 if (xfrm6_local_dontfrag(sk))
857 ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
858 else if (sk)
859 xfrm_local_error(skb, mtu);
860 else
861 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
862 ret = -EMSGSIZE;
863 }
864 out:
865 return ret;
866 }
867 #endif
868
xfrm6_extract_output(struct xfrm_state * x,struct sk_buff * skb)869 static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
870 {
871 #if IS_ENABLED(CONFIG_IPV6)
872 int err;
873
874 err = xfrm6_tunnel_check_size(skb);
875 if (err)
876 return err;
877
878 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
879
880 xfrm6_extract_header(skb);
881 return 0;
882 #else
883 WARN_ON_ONCE(1);
884 return -EAFNOSUPPORT;
885 #endif
886 }
887
xfrm_inner_extract_output(struct xfrm_state * x,struct sk_buff * skb)888 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
889 {
890 switch (skb->protocol) {
891 case htons(ETH_P_IP):
892 return xfrm4_extract_output(x, skb);
893 case htons(ETH_P_IPV6):
894 return xfrm6_extract_output(x, skb);
895 }
896
897 return -EAFNOSUPPORT;
898 }
899
xfrm_local_error(struct sk_buff * skb,int mtu)900 void xfrm_local_error(struct sk_buff *skb, int mtu)
901 {
902 unsigned int proto;
903 struct xfrm_state_afinfo *afinfo;
904
905 if (skb->protocol == htons(ETH_P_IP))
906 proto = AF_INET;
907 else if (skb->protocol == htons(ETH_P_IPV6) &&
908 skb->sk->sk_family == AF_INET6)
909 proto = AF_INET6;
910 else
911 return;
912
913 afinfo = xfrm_state_get_afinfo(proto);
914 if (afinfo) {
915 afinfo->local_error(skb, mtu);
916 rcu_read_unlock();
917 }
918 }
919 EXPORT_SYMBOL_GPL(xfrm_local_error);
920