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 WARN_ON_ONCE(1);
476 break;
477 }
478
479 return -EOPNOTSUPP;
480 }
481
pktgen_xfrm_outer_mode_output(struct xfrm_state * x,struct sk_buff * skb)482 int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
483 {
484 return xfrm_outer_mode_output(x, skb);
485 }
486 EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
487
xfrm_output_one(struct sk_buff * skb,int err)488 static int xfrm_output_one(struct sk_buff *skb, int err)
489 {
490 struct dst_entry *dst = skb_dst(skb);
491 struct xfrm_state *x = dst->xfrm;
492 struct net *net = xs_net(x);
493
494 if (err <= 0 || x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
495 goto resume;
496
497 do {
498 err = xfrm_skb_check_space(skb);
499 if (err) {
500 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
501 goto error_nolock;
502 }
503
504 skb->mark = xfrm_smark_get(skb->mark, x);
505
506 err = xfrm_outer_mode_output(x, skb);
507 if (err) {
508 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
509 goto error_nolock;
510 }
511
512 spin_lock_bh(&x->lock);
513
514 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
515 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
516 err = -EINVAL;
517 goto error;
518 }
519
520 err = xfrm_state_check_expire(x);
521 if (err) {
522 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
523 goto error;
524 }
525
526 err = xfrm_replay_overflow(x, skb);
527 if (err) {
528 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
529 goto error;
530 }
531
532 x->curlft.bytes += skb->len;
533 x->curlft.packets++;
534 x->lastused = ktime_get_real_seconds();
535
536 spin_unlock_bh(&x->lock);
537
538 skb_dst_force(skb);
539 if (!skb_dst(skb)) {
540 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
541 err = -EHOSTUNREACH;
542 goto error_nolock;
543 }
544
545 if (xfrm_offload(skb)) {
546 x->type_offload->encap(x, skb);
547 } else {
548 /* Inner headers are invalid now. */
549 skb->encapsulation = 0;
550
551 err = x->type->output(x, skb);
552 if (err == -EINPROGRESS)
553 goto out;
554 }
555
556 resume:
557 if (err) {
558 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
559 goto error_nolock;
560 }
561
562 dst = skb_dst_pop(skb);
563 if (!dst) {
564 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
565 err = -EHOSTUNREACH;
566 goto error_nolock;
567 }
568 skb_dst_set(skb, dst);
569 x = dst->xfrm;
570 } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
571
572 return 0;
573
574 error:
575 spin_unlock_bh(&x->lock);
576 error_nolock:
577 kfree_skb(skb);
578 out:
579 return err;
580 }
581
xfrm_output_resume(struct sock * sk,struct sk_buff * skb,int err)582 int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
583 {
584 struct net *net = xs_net(skb_dst(skb)->xfrm);
585
586 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
587 nf_reset_ct(skb);
588
589 err = skb_dst(skb)->ops->local_out(net, sk, skb);
590 if (unlikely(err != 1))
591 goto out;
592
593 if (!skb_dst(skb)->xfrm)
594 return dst_output(net, sk, skb);
595
596 err = nf_hook(skb_dst(skb)->ops->family,
597 NF_INET_POST_ROUTING, net, sk, skb,
598 NULL, skb_dst(skb)->dev, xfrm_output2);
599 if (unlikely(err != 1))
600 goto out;
601 }
602
603 if (err == -EINPROGRESS)
604 err = 0;
605
606 out:
607 return err;
608 }
609 EXPORT_SYMBOL_GPL(xfrm_output_resume);
610
xfrm_dev_direct_output(struct sock * sk,struct xfrm_state * x,struct sk_buff * skb)611 static int xfrm_dev_direct_output(struct sock *sk, struct xfrm_state *x,
612 struct sk_buff *skb)
613 {
614 struct dst_entry *dst = skb_dst(skb);
615 struct net *net = xs_net(x);
616 int err;
617
618 dst = skb_dst_pop(skb);
619 if (!dst) {
620 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
621 kfree_skb(skb);
622 return -EHOSTUNREACH;
623 }
624 skb_dst_set(skb, dst);
625 nf_reset_ct(skb);
626
627 err = skb_dst(skb)->ops->local_out(net, sk, skb);
628 if (unlikely(err != 1)) {
629 kfree_skb(skb);
630 return err;
631 }
632
633 /* In transport mode, network destination is
634 * directly reachable, while in tunnel mode,
635 * inner packet network may not be. In packet
636 * offload type, HW is responsible for hard
637 * header packet mangling so directly xmit skb
638 * to netdevice.
639 */
640 skb->dev = x->xso.dev;
641 __skb_push(skb, skb->dev->hard_header_len);
642 return dev_queue_xmit(skb);
643 }
644
xfrm_output2(struct net * net,struct sock * sk,struct sk_buff * skb)645 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
646 {
647 return xfrm_output_resume(sk, skb, 1);
648 }
649
xfrm_output_gso(struct net * net,struct sock * sk,struct sk_buff * skb)650 static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
651 {
652 struct sk_buff *segs, *nskb;
653
654 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
655 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
656 segs = skb_gso_segment(skb, 0);
657 kfree_skb(skb);
658 if (IS_ERR(segs))
659 return PTR_ERR(segs);
660 if (segs == NULL)
661 return -EINVAL;
662
663 skb_list_walk_safe(segs, segs, nskb) {
664 int err;
665
666 skb_mark_not_on_list(segs);
667 err = xfrm_output2(net, sk, segs);
668
669 if (unlikely(err)) {
670 kfree_skb_list(nskb);
671 return err;
672 }
673 }
674
675 return 0;
676 }
677
678 /* For partial checksum offload, the outer header checksum is calculated
679 * by software and the inner header checksum is calculated by hardware.
680 * This requires hardware to know the inner packet type to calculate
681 * the inner header checksum. Save inner ip protocol here to avoid
682 * traversing the packet in the vendor's xmit code.
683 * For IPsec tunnel mode save the ip protocol from the IP header of the
684 * plain text packet. Otherwise If the encap type is IPIP, just save
685 * skb->inner_ipproto in any other case get the ip protocol from the IP
686 * header.
687 */
xfrm_get_inner_ipproto(struct sk_buff * skb,struct xfrm_state * x)688 static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
689 {
690 struct xfrm_offload *xo = xfrm_offload(skb);
691 const struct ethhdr *eth;
692
693 if (!xo)
694 return;
695
696 if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
697 switch (x->outer_mode.family) {
698 case AF_INET:
699 xo->inner_ipproto = ip_hdr(skb)->protocol;
700 break;
701 case AF_INET6:
702 xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
703 break;
704 default:
705 break;
706 }
707
708 return;
709 }
710
711 /* non-Tunnel Mode */
712 if (!skb->encapsulation)
713 return;
714
715 if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
716 xo->inner_ipproto = skb->inner_ipproto;
717 return;
718 }
719
720 if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
721 return;
722
723 eth = (struct ethhdr *)skb_inner_mac_header(skb);
724
725 switch (ntohs(eth->h_proto)) {
726 case ETH_P_IPV6:
727 xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
728 break;
729 case ETH_P_IP:
730 xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
731 break;
732 }
733 }
734
xfrm_output(struct sock * sk,struct sk_buff * skb)735 int xfrm_output(struct sock *sk, struct sk_buff *skb)
736 {
737 struct net *net = dev_net(skb_dst(skb)->dev);
738 struct xfrm_state *x = skb_dst(skb)->xfrm;
739 int family;
740 int err;
741
742 family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
743 : skb_dst(skb)->ops->family;
744
745 switch (family) {
746 case AF_INET:
747 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
748 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
749 break;
750 case AF_INET6:
751 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
752
753 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
754 break;
755 }
756
757 if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) {
758 if (!xfrm_dev_offload_ok(skb, x)) {
759 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
760 kfree_skb(skb);
761 return -EHOSTUNREACH;
762 }
763
764 /* Exclusive direct xmit for tunnel mode, as
765 * some filtering or matching rules may apply
766 * in transport mode.
767 */
768 if (x->props.mode == XFRM_MODE_TUNNEL)
769 return xfrm_dev_direct_output(sk, x, skb);
770
771 return xfrm_output_resume(sk, skb, 0);
772 }
773
774 secpath_reset(skb);
775
776 if (xfrm_dev_offload_ok(skb, x)) {
777 struct sec_path *sp;
778
779 sp = secpath_set(skb);
780 if (!sp) {
781 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
782 kfree_skb(skb);
783 return -ENOMEM;
784 }
785
786 sp->olen++;
787 sp->xvec[sp->len++] = x;
788 xfrm_state_hold(x);
789
790 xfrm_get_inner_ipproto(skb, x);
791 skb->encapsulation = 1;
792
793 if (skb_is_gso(skb)) {
794 if (skb->inner_protocol && x->props.mode == XFRM_MODE_TUNNEL)
795 return xfrm_output_gso(net, sk, skb);
796
797 skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
798 goto out;
799 }
800
801 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
802 goto out;
803 } else {
804 if (skb_is_gso(skb))
805 return xfrm_output_gso(net, sk, skb);
806 }
807
808 if (skb->ip_summed == CHECKSUM_PARTIAL) {
809 err = skb_checksum_help(skb);
810 if (err) {
811 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
812 kfree_skb(skb);
813 return err;
814 }
815 }
816
817 out:
818 return xfrm_output2(net, sk, skb);
819 }
820 EXPORT_SYMBOL_GPL(xfrm_output);
821
xfrm4_tunnel_check_size(struct sk_buff * skb)822 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
823 {
824 int mtu, ret = 0;
825
826 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
827 goto out;
828
829 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
830 goto out;
831
832 mtu = dst_mtu(skb_dst(skb));
833 if ((!skb_is_gso(skb) && skb->len > mtu) ||
834 (skb_is_gso(skb) &&
835 !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
836 skb->protocol = htons(ETH_P_IP);
837
838 if (skb->sk)
839 xfrm_local_error(skb, mtu);
840 else
841 icmp_send(skb, ICMP_DEST_UNREACH,
842 ICMP_FRAG_NEEDED, htonl(mtu));
843 ret = -EMSGSIZE;
844 }
845 out:
846 return ret;
847 }
848
xfrm4_extract_output(struct xfrm_state * x,struct sk_buff * skb)849 static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
850 {
851 int err;
852
853 if (x->outer_mode.encap == XFRM_MODE_BEET &&
854 ip_is_fragment(ip_hdr(skb))) {
855 net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
856 return -EAFNOSUPPORT;
857 }
858
859 err = xfrm4_tunnel_check_size(skb);
860 if (err)
861 return err;
862
863 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
864
865 xfrm4_extract_header(skb);
866 return 0;
867 }
868
869 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_tunnel_check_size(struct sk_buff * skb)870 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
871 {
872 int mtu, ret = 0;
873 struct dst_entry *dst = skb_dst(skb);
874
875 if (skb->ignore_df)
876 goto out;
877
878 mtu = dst_mtu(dst);
879 if (mtu < IPV6_MIN_MTU)
880 mtu = IPV6_MIN_MTU;
881
882 if ((!skb_is_gso(skb) && skb->len > mtu) ||
883 (skb_is_gso(skb) &&
884 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
885 skb->dev = dst->dev;
886 skb->protocol = htons(ETH_P_IPV6);
887
888 if (xfrm6_local_dontfrag(skb->sk))
889 ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
890 else if (skb->sk)
891 xfrm_local_error(skb, mtu);
892 else
893 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
894 ret = -EMSGSIZE;
895 }
896 out:
897 return ret;
898 }
899 #endif
900
xfrm6_extract_output(struct xfrm_state * x,struct sk_buff * skb)901 static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
902 {
903 #if IS_ENABLED(CONFIG_IPV6)
904 int err;
905
906 err = xfrm6_tunnel_check_size(skb);
907 if (err)
908 return err;
909
910 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
911
912 xfrm6_extract_header(skb);
913 return 0;
914 #else
915 WARN_ON_ONCE(1);
916 return -EAFNOSUPPORT;
917 #endif
918 }
919
xfrm_inner_extract_output(struct xfrm_state * x,struct sk_buff * skb)920 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
921 {
922 switch (skb->protocol) {
923 case htons(ETH_P_IP):
924 return xfrm4_extract_output(x, skb);
925 case htons(ETH_P_IPV6):
926 return xfrm6_extract_output(x, skb);
927 }
928
929 return -EAFNOSUPPORT;
930 }
931
xfrm_local_error(struct sk_buff * skb,int mtu)932 void xfrm_local_error(struct sk_buff *skb, int mtu)
933 {
934 unsigned int proto;
935 struct xfrm_state_afinfo *afinfo;
936
937 if (skb->protocol == htons(ETH_P_IP))
938 proto = AF_INET;
939 else if (skb->protocol == htons(ETH_P_IPV6) &&
940 skb->sk->sk_family == AF_INET6)
941 proto = AF_INET6;
942 else
943 return;
944
945 afinfo = xfrm_state_get_afinfo(proto);
946 if (afinfo) {
947 afinfo->local_error(skb, mtu);
948 rcu_read_unlock();
949 }
950 }
951 EXPORT_SYMBOL_GPL(xfrm_local_error);
952