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 
27 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
28 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
29 
xfrm_skb_check_space(struct sk_buff * skb)30 static 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 
skb_dst_pop(struct sk_buff * skb)51 static 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  */
xfrm4_transport_output(struct xfrm_state * x,struct sk_buff * skb)64 static 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)
mip6_rthdr_offset(struct sk_buff * skb,u8 ** nexthdr,int type)81 static 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)
xfrm6_hdr_offset(struct xfrm_state * x,struct sk_buff * skb,u8 ** prevhdr)141 static 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  */
xfrm6_transport_output(struct xfrm_state * x,struct sk_buff * skb)162 static 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  */
xfrm6_ro_output(struct xfrm_state * x,struct sk_buff * skb)193 static 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 	x->lastused = ktime_get_real_seconds();
213 
214 	return 0;
215 #else
216 	WARN_ON_ONCE(1);
217 	return -EAFNOSUPPORT;
218 #endif
219 }
220 
221 /* Add encapsulation header.
222  *
223  * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
224  */
xfrm4_beet_encap_add(struct xfrm_state * x,struct sk_buff * skb)225 static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
226 {
227 	struct ip_beet_phdr *ph;
228 	struct iphdr *top_iph;
229 	int hdrlen, optlen;
230 
231 	hdrlen = 0;
232 	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
233 	if (unlikely(optlen))
234 		hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
235 
236 	skb_set_network_header(skb, -x->props.header_len - hdrlen +
237 			       (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
238 	if (x->sel.family != AF_INET6)
239 		skb->network_header += IPV4_BEET_PHMAXLEN;
240 	skb->mac_header = skb->network_header +
241 			  offsetof(struct iphdr, protocol);
242 	skb->transport_header = skb->network_header + sizeof(*top_iph);
243 
244 	xfrm4_beet_make_header(skb);
245 
246 	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
247 
248 	top_iph = ip_hdr(skb);
249 
250 	if (unlikely(optlen)) {
251 		if (WARN_ON(optlen < 0))
252 			return -EINVAL;
253 
254 		ph->padlen = 4 - (optlen & 4);
255 		ph->hdrlen = optlen / 8;
256 		ph->nexthdr = top_iph->protocol;
257 		if (ph->padlen)
258 			memset(ph + 1, IPOPT_NOP, ph->padlen);
259 
260 		top_iph->protocol = IPPROTO_BEETPH;
261 		top_iph->ihl = sizeof(struct iphdr) / 4;
262 	}
263 
264 	top_iph->saddr = x->props.saddr.a4;
265 	top_iph->daddr = x->id.daddr.a4;
266 
267 	return 0;
268 }
269 
270 /* Add encapsulation header.
271  *
272  * The top IP header will be constructed per RFC 2401.
273  */
xfrm4_tunnel_encap_add(struct xfrm_state * x,struct sk_buff * skb)274 static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
275 {
276 	bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
277 	struct dst_entry *dst = skb_dst(skb);
278 	struct iphdr *top_iph;
279 	int flags;
280 
281 	skb_set_inner_network_header(skb, skb_network_offset(skb));
282 	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
283 
284 	skb_set_network_header(skb, -x->props.header_len);
285 	skb->mac_header = skb->network_header +
286 			  offsetof(struct iphdr, protocol);
287 	skb->transport_header = skb->network_header + sizeof(*top_iph);
288 	top_iph = ip_hdr(skb);
289 
290 	top_iph->ihl = 5;
291 	top_iph->version = 4;
292 
293 	top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
294 
295 	/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
296 	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
297 		top_iph->tos = 0;
298 	else
299 		top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
300 	top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
301 					    XFRM_MODE_SKB_CB(skb)->tos);
302 
303 	flags = x->props.flags;
304 	if (flags & XFRM_STATE_NOECN)
305 		IP_ECN_clear(top_iph);
306 
307 	top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
308 		0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
309 
310 	top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
311 
312 	top_iph->saddr = x->props.saddr.a4;
313 	top_iph->daddr = x->id.daddr.a4;
314 	ip_select_ident(dev_net(dst->dev), skb, NULL);
315 
316 	return 0;
317 }
318 
319 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_tunnel_encap_add(struct xfrm_state * x,struct sk_buff * skb)320 static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
321 {
322 	struct dst_entry *dst = skb_dst(skb);
323 	struct ipv6hdr *top_iph;
324 	int dsfield;
325 
326 	skb_set_inner_network_header(skb, skb_network_offset(skb));
327 	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
328 
329 	skb_set_network_header(skb, -x->props.header_len);
330 	skb->mac_header = skb->network_header +
331 			  offsetof(struct ipv6hdr, nexthdr);
332 	skb->transport_header = skb->network_header + sizeof(*top_iph);
333 	top_iph = ipv6_hdr(skb);
334 
335 	top_iph->version = 6;
336 
337 	memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
338 	       sizeof(top_iph->flow_lbl));
339 	top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
340 
341 	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
342 		dsfield = 0;
343 	else
344 		dsfield = XFRM_MODE_SKB_CB(skb)->tos;
345 	dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
346 	if (x->props.flags & XFRM_STATE_NOECN)
347 		dsfield &= ~INET_ECN_MASK;
348 	ipv6_change_dsfield(top_iph, 0, dsfield);
349 	top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
350 	top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
351 	top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
352 	return 0;
353 }
354 
xfrm6_beet_encap_add(struct xfrm_state * x,struct sk_buff * skb)355 static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
356 {
357 	struct ipv6hdr *top_iph;
358 	struct ip_beet_phdr *ph;
359 	int optlen, hdr_len;
360 
361 	hdr_len = 0;
362 	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
363 	if (unlikely(optlen))
364 		hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
365 
366 	skb_set_network_header(skb, -x->props.header_len - hdr_len);
367 	if (x->sel.family != AF_INET6)
368 		skb->network_header += IPV4_BEET_PHMAXLEN;
369 	skb->mac_header = skb->network_header +
370 			  offsetof(struct ipv6hdr, nexthdr);
371 	skb->transport_header = skb->network_header + sizeof(*top_iph);
372 	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
373 
374 	xfrm6_beet_make_header(skb);
375 
376 	top_iph = ipv6_hdr(skb);
377 	if (unlikely(optlen)) {
378 		if (WARN_ON(optlen < 0))
379 			return -EINVAL;
380 
381 		ph->padlen = 4 - (optlen & 4);
382 		ph->hdrlen = optlen / 8;
383 		ph->nexthdr = top_iph->nexthdr;
384 		if (ph->padlen)
385 			memset(ph + 1, IPOPT_NOP, ph->padlen);
386 
387 		top_iph->nexthdr = IPPROTO_BEETPH;
388 	}
389 
390 	top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
391 	top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
392 	return 0;
393 }
394 #endif
395 
396 /* Add encapsulation header.
397  *
398  * On exit, the transport header will be set to the start of the
399  * encapsulation header to be filled in by x->type->output and the mac
400  * header will be set to the nextheader (protocol for IPv4) field of the
401  * extension header directly preceding the encapsulation header, or in
402  * its absence, that of the top IP header.
403  * The value of the network header will always point to the top IP header
404  * while skb->data will point to the payload.
405  */
xfrm4_prepare_output(struct xfrm_state * x,struct sk_buff * skb)406 static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
407 {
408 	int err;
409 
410 	err = xfrm_inner_extract_output(x, skb);
411 	if (err)
412 		return err;
413 
414 	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
415 	skb->protocol = htons(ETH_P_IP);
416 
417 	switch (x->outer_mode.encap) {
418 	case XFRM_MODE_BEET:
419 		return xfrm4_beet_encap_add(x, skb);
420 	case XFRM_MODE_TUNNEL:
421 		return xfrm4_tunnel_encap_add(x, skb);
422 	}
423 
424 	WARN_ON_ONCE(1);
425 	return -EOPNOTSUPP;
426 }
427 
xfrm6_prepare_output(struct xfrm_state * x,struct sk_buff * skb)428 static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
429 {
430 #if IS_ENABLED(CONFIG_IPV6)
431 	int err;
432 
433 	err = xfrm_inner_extract_output(x, skb);
434 	if (err)
435 		return err;
436 
437 	skb->ignore_df = 1;
438 	skb->protocol = htons(ETH_P_IPV6);
439 
440 	switch (x->outer_mode.encap) {
441 	case XFRM_MODE_BEET:
442 		return xfrm6_beet_encap_add(x, skb);
443 	case XFRM_MODE_TUNNEL:
444 		return xfrm6_tunnel_encap_add(x, skb);
445 	default:
446 		WARN_ON_ONCE(1);
447 		return -EOPNOTSUPP;
448 	}
449 #endif
450 	WARN_ON_ONCE(1);
451 	return -EAFNOSUPPORT;
452 }
453 
xfrm_outer_mode_output(struct xfrm_state * x,struct sk_buff * skb)454 static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
455 {
456 	switch (x->outer_mode.encap) {
457 	case XFRM_MODE_BEET:
458 	case XFRM_MODE_TUNNEL:
459 		if (x->outer_mode.family == AF_INET)
460 			return xfrm4_prepare_output(x, skb);
461 		if (x->outer_mode.family == AF_INET6)
462 			return xfrm6_prepare_output(x, skb);
463 		break;
464 	case XFRM_MODE_TRANSPORT:
465 		if (x->outer_mode.family == AF_INET)
466 			return xfrm4_transport_output(x, skb);
467 		if (x->outer_mode.family == AF_INET6)
468 			return xfrm6_transport_output(x, skb);
469 		break;
470 	case XFRM_MODE_ROUTEOPTIMIZATION:
471 		if (x->outer_mode.family == AF_INET6)
472 			return xfrm6_ro_output(x, skb);
473 		WARN_ON_ONCE(1);
474 		break;
475 	default:
476 		WARN_ON_ONCE(1);
477 		break;
478 	}
479 
480 	return -EOPNOTSUPP;
481 }
482 
483 #if IS_ENABLED(CONFIG_NET_PKTGEN)
pktgen_xfrm_outer_mode_output(struct xfrm_state * x,struct sk_buff * skb)484 int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
485 {
486 	return xfrm_outer_mode_output(x, skb);
487 }
488 EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
489 #endif
490 
xfrm_output_one(struct sk_buff * skb,int err)491 static int xfrm_output_one(struct sk_buff *skb, int err)
492 {
493 	struct dst_entry *dst = skb_dst(skb);
494 	struct xfrm_state *x = dst->xfrm;
495 	struct net *net = xs_net(x);
496 
497 	if (err <= 0)
498 		goto resume;
499 
500 	do {
501 		err = xfrm_skb_check_space(skb);
502 		if (err) {
503 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
504 			goto error_nolock;
505 		}
506 
507 		skb->mark = xfrm_smark_get(skb->mark, x);
508 
509 		err = xfrm_outer_mode_output(x, skb);
510 		if (err) {
511 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
512 			goto error_nolock;
513 		}
514 
515 		spin_lock_bh(&x->lock);
516 
517 		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
518 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
519 			err = -EINVAL;
520 			goto error;
521 		}
522 
523 		err = xfrm_state_check_expire(x);
524 		if (err) {
525 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
526 			goto error;
527 		}
528 
529 		err = xfrm_replay_overflow(x, skb);
530 		if (err) {
531 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
532 			goto error;
533 		}
534 
535 		x->curlft.bytes += skb->len;
536 		x->curlft.packets++;
537 
538 		spin_unlock_bh(&x->lock);
539 
540 		skb_dst_force(skb);
541 		if (!skb_dst(skb)) {
542 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
543 			err = -EHOSTUNREACH;
544 			goto error_nolock;
545 		}
546 
547 		if (xfrm_offload(skb)) {
548 			x->type_offload->encap(x, skb);
549 		} else {
550 			/* Inner headers are invalid now. */
551 			skb->encapsulation = 0;
552 
553 			err = x->type->output(x, skb);
554 			if (err == -EINPROGRESS)
555 				goto out;
556 		}
557 
558 resume:
559 		if (err) {
560 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
561 			goto error_nolock;
562 		}
563 
564 		dst = skb_dst_pop(skb);
565 		if (!dst) {
566 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
567 			err = -EHOSTUNREACH;
568 			goto error_nolock;
569 		}
570 		skb_dst_set(skb, dst);
571 		x = dst->xfrm;
572 	} while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
573 
574 	return 0;
575 
576 error:
577 	spin_unlock_bh(&x->lock);
578 error_nolock:
579 	kfree_skb(skb);
580 out:
581 	return err;
582 }
583 
xfrm_output_resume(struct sock * sk,struct sk_buff * skb,int err)584 int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
585 {
586 	struct net *net = xs_net(skb_dst(skb)->xfrm);
587 
588 	while (likely((err = xfrm_output_one(skb, err)) == 0)) {
589 		nf_reset_ct(skb);
590 
591 		err = skb_dst(skb)->ops->local_out(net, sk, skb);
592 		if (unlikely(err != 1))
593 			goto out;
594 
595 		if (!skb_dst(skb)->xfrm)
596 			return dst_output(net, sk, skb);
597 
598 		err = nf_hook(skb_dst(skb)->ops->family,
599 			      NF_INET_POST_ROUTING, net, sk, skb,
600 			      NULL, skb_dst(skb)->dev, xfrm_output2);
601 		if (unlikely(err != 1))
602 			goto out;
603 	}
604 
605 	if (err == -EINPROGRESS)
606 		err = 0;
607 
608 out:
609 	return err;
610 }
611 EXPORT_SYMBOL_GPL(xfrm_output_resume);
612 
xfrm_output2(struct net * net,struct sock * sk,struct sk_buff * skb)613 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
614 {
615 	return xfrm_output_resume(sk, skb, 1);
616 }
617 
xfrm_output_gso(struct net * net,struct sock * sk,struct sk_buff * skb)618 static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
619 {
620 	struct sk_buff *segs, *nskb;
621 
622 	BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
623 	BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
624 	segs = skb_gso_segment(skb, 0);
625 	kfree_skb(skb);
626 	if (IS_ERR(segs))
627 		return PTR_ERR(segs);
628 	if (segs == NULL)
629 		return -EINVAL;
630 
631 	skb_list_walk_safe(segs, segs, nskb) {
632 		int err;
633 
634 		skb_mark_not_on_list(segs);
635 		err = xfrm_output2(net, sk, segs);
636 
637 		if (unlikely(err)) {
638 			kfree_skb_list(nskb);
639 			return err;
640 		}
641 	}
642 
643 	return 0;
644 }
645 
646 /* For partial checksum offload, the outer header checksum is calculated
647  * by software and the inner header checksum is calculated by hardware.
648  * This requires hardware to know the inner packet type to calculate
649  * the inner header checksum. Save inner ip protocol here to avoid
650  * traversing the packet in the vendor's xmit code.
651  * For IPsec tunnel mode save the ip protocol from the IP header of the
652  * plain text packet. Otherwise If the encap type is IPIP, just save
653  * skb->inner_ipproto in any other case get the ip protocol from the IP
654  * header.
655  */
xfrm_get_inner_ipproto(struct sk_buff * skb,struct xfrm_state * x)656 static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
657 {
658 	struct xfrm_offload *xo = xfrm_offload(skb);
659 	const struct ethhdr *eth;
660 
661 	if (!xo)
662 		return;
663 
664 	if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
665 		switch (x->outer_mode.family) {
666 		case AF_INET:
667 			xo->inner_ipproto = ip_hdr(skb)->protocol;
668 			break;
669 		case AF_INET6:
670 			xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
671 			break;
672 		default:
673 			break;
674 		}
675 
676 		return;
677 	}
678 
679 	/* non-Tunnel Mode */
680 	if (!skb->encapsulation)
681 		return;
682 
683 	if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
684 		xo->inner_ipproto = skb->inner_ipproto;
685 		return;
686 	}
687 
688 	if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
689 		return;
690 
691 	eth = (struct ethhdr *)skb_inner_mac_header(skb);
692 
693 	switch (ntohs(eth->h_proto)) {
694 	case ETH_P_IPV6:
695 		xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
696 		break;
697 	case ETH_P_IP:
698 		xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
699 		break;
700 	}
701 }
702 
xfrm_output(struct sock * sk,struct sk_buff * skb)703 int xfrm_output(struct sock *sk, struct sk_buff *skb)
704 {
705 	struct net *net = dev_net(skb_dst(skb)->dev);
706 	struct xfrm_state *x = skb_dst(skb)->xfrm;
707 	int err;
708 
709 	switch (x->outer_mode.family) {
710 	case AF_INET:
711 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
712 		IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
713 		break;
714 	case AF_INET6:
715 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
716 
717 		IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
718 		break;
719 	}
720 
721 	secpath_reset(skb);
722 
723 	if (xfrm_dev_offload_ok(skb, x)) {
724 		struct sec_path *sp;
725 
726 		sp = secpath_set(skb);
727 		if (!sp) {
728 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
729 			kfree_skb(skb);
730 			return -ENOMEM;
731 		}
732 
733 		sp->olen++;
734 		sp->xvec[sp->len++] = x;
735 		xfrm_state_hold(x);
736 
737 		xfrm_get_inner_ipproto(skb, x);
738 		skb->encapsulation = 1;
739 
740 		if (skb_is_gso(skb)) {
741 			if (skb->inner_protocol)
742 				return xfrm_output_gso(net, sk, skb);
743 
744 			skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
745 			goto out;
746 		}
747 
748 		if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
749 			goto out;
750 	} else {
751 		if (skb_is_gso(skb))
752 			return xfrm_output_gso(net, sk, skb);
753 	}
754 
755 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
756 		err = skb_checksum_help(skb);
757 		if (err) {
758 			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
759 			kfree_skb(skb);
760 			return err;
761 		}
762 	}
763 
764 out:
765 	return xfrm_output2(net, sk, skb);
766 }
767 EXPORT_SYMBOL_GPL(xfrm_output);
768 
xfrm4_tunnel_check_size(struct sk_buff * skb)769 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
770 {
771 	int mtu, ret = 0;
772 
773 	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
774 		goto out;
775 
776 	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
777 		goto out;
778 
779 	mtu = dst_mtu(skb_dst(skb));
780 	if ((!skb_is_gso(skb) && skb->len > mtu) ||
781 	    (skb_is_gso(skb) &&
782 	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
783 		skb->protocol = htons(ETH_P_IP);
784 
785 		if (skb->sk)
786 			xfrm_local_error(skb, mtu);
787 		else
788 			icmp_send(skb, ICMP_DEST_UNREACH,
789 				  ICMP_FRAG_NEEDED, htonl(mtu));
790 		ret = -EMSGSIZE;
791 	}
792 out:
793 	return ret;
794 }
795 
xfrm4_extract_output(struct xfrm_state * x,struct sk_buff * skb)796 static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
797 {
798 	int err;
799 
800 	if (x->outer_mode.encap == XFRM_MODE_BEET &&
801 	    ip_is_fragment(ip_hdr(skb))) {
802 		net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
803 		return -EAFNOSUPPORT;
804 	}
805 
806 	err = xfrm4_tunnel_check_size(skb);
807 	if (err)
808 		return err;
809 
810 	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
811 
812 	xfrm4_extract_header(skb);
813 	return 0;
814 }
815 
816 #if IS_ENABLED(CONFIG_IPV6)
xfrm6_tunnel_check_size(struct sk_buff * skb)817 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
818 {
819 	int mtu, ret = 0;
820 	struct dst_entry *dst = skb_dst(skb);
821 
822 	if (skb->ignore_df)
823 		goto out;
824 
825 	mtu = dst_mtu(dst);
826 	if (mtu < IPV6_MIN_MTU)
827 		mtu = IPV6_MIN_MTU;
828 
829 	if ((!skb_is_gso(skb) && skb->len > mtu) ||
830 	    (skb_is_gso(skb) &&
831 	     !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
832 		skb->dev = dst->dev;
833 		skb->protocol = htons(ETH_P_IPV6);
834 
835 		if (xfrm6_local_dontfrag(skb->sk))
836 			ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
837 		else if (skb->sk)
838 			xfrm_local_error(skb, mtu);
839 		else
840 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
841 		ret = -EMSGSIZE;
842 	}
843 out:
844 	return ret;
845 }
846 #endif
847 
xfrm6_extract_output(struct xfrm_state * x,struct sk_buff * skb)848 static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
849 {
850 #if IS_ENABLED(CONFIG_IPV6)
851 	int err;
852 
853 	err = xfrm6_tunnel_check_size(skb);
854 	if (err)
855 		return err;
856 
857 	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
858 
859 	xfrm6_extract_header(skb);
860 	return 0;
861 #else
862 	WARN_ON_ONCE(1);
863 	return -EAFNOSUPPORT;
864 #endif
865 }
866 
xfrm_inner_extract_output(struct xfrm_state * x,struct sk_buff * skb)867 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
868 {
869 	const struct xfrm_mode *inner_mode;
870 
871 	if (x->sel.family == AF_UNSPEC)
872 		inner_mode = xfrm_ip2inner_mode(x,
873 				xfrm_af2proto(skb_dst(skb)->ops->family));
874 	else
875 		inner_mode = &x->inner_mode;
876 
877 	if (inner_mode == NULL)
878 		return -EAFNOSUPPORT;
879 
880 	switch (inner_mode->family) {
881 	case AF_INET:
882 		return xfrm4_extract_output(x, skb);
883 	case AF_INET6:
884 		return xfrm6_extract_output(x, skb);
885 	}
886 
887 	return -EAFNOSUPPORT;
888 }
889 
xfrm_local_error(struct sk_buff * skb,int mtu)890 void xfrm_local_error(struct sk_buff *skb, int mtu)
891 {
892 	unsigned int proto;
893 	struct xfrm_state_afinfo *afinfo;
894 
895 	if (skb->protocol == htons(ETH_P_IP))
896 		proto = AF_INET;
897 	else if (skb->protocol == htons(ETH_P_IPV6) &&
898 		 skb->sk->sk_family == AF_INET6)
899 		proto = AF_INET6;
900 	else
901 		return;
902 
903 	afinfo = xfrm_state_get_afinfo(proto);
904 	if (afinfo) {
905 		afinfo->local_error(skb, mtu);
906 		rcu_read_unlock();
907 	}
908 }
909 EXPORT_SYMBOL_GPL(xfrm_local_error);
910