1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * xfrm_output.c - Common IPsec encapsulation code.
  4 *
  5 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 
 
 
 
 
  6 */
  7
  8#include <linux/errno.h>
  9#include <linux/module.h>
 10#include <linux/netdevice.h>
 11#include <linux/netfilter.h>
 12#include <linux/skbuff.h>
 13#include <linux/slab.h>
 14#include <linux/spinlock.h>
 15#include <net/dst.h>
 16#include <net/icmp.h>
 17#include <net/inet_ecn.h>
 18#include <net/xfrm.h>
 19
 20#if IS_ENABLED(CONFIG_IPV6)
 21#include <net/ip6_route.h>
 22#include <net/ipv6_stubs.h>
 23#endif
 24
 25#include "xfrm_inout.h"
 26
 27static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
 28static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
 29
 30static int xfrm_skb_check_space(struct sk_buff *skb)
 31{
 32	struct dst_entry *dst = skb_dst(skb);
 33	int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
 34		- skb_headroom(skb);
 35	int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
 36
 37	if (nhead <= 0) {
 38		if (ntail <= 0)
 39			return 0;
 40		nhead = 0;
 41	} else if (ntail < 0)
 42		ntail = 0;
 43
 44	return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
 45}
 46
 47/* Children define the path of the packet through the
 48 * Linux networking.  Thus, destinations are stackable.
 49 */
 50
 51static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
 52{
 53	struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
 54
 55	skb_dst_drop(skb);
 56	return child;
 57}
 58
 59/* Add encapsulation header.
 60 *
 61 * The IP header will be moved forward to make space for the encapsulation
 62 * header.
 63 */
 64static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 65{
 66	struct iphdr *iph = ip_hdr(skb);
 67	int ihl = iph->ihl * 4;
 68
 69	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
 70
 71	skb_set_network_header(skb, -x->props.header_len);
 72	skb->mac_header = skb->network_header +
 73			  offsetof(struct iphdr, protocol);
 74	skb->transport_header = skb->network_header + ihl;
 75	__skb_pull(skb, ihl);
 76	memmove(skb_network_header(skb), iph, ihl);
 77	return 0;
 78}
 79
 80#if IS_ENABLED(CONFIG_IPV6_MIP6)
 81static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
 82{
 83	const unsigned char *nh = skb_network_header(skb);
 84	unsigned int offset = sizeof(struct ipv6hdr);
 85	unsigned int packet_len;
 86	int found_rhdr = 0;
 87
 88	packet_len = skb_tail_pointer(skb) - nh;
 89	*nexthdr = &ipv6_hdr(skb)->nexthdr;
 90
 91	while (offset <= packet_len) {
 92		struct ipv6_opt_hdr *exthdr;
 93
 94		switch (**nexthdr) {
 95		case NEXTHDR_HOP:
 96			break;
 97		case NEXTHDR_ROUTING:
 98			if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
 99				struct ipv6_rt_hdr *rt;
100
101				rt = (struct ipv6_rt_hdr *)(nh + offset);
102				if (rt->type != 0)
103					return offset;
104			}
105			found_rhdr = 1;
106			break;
107		case NEXTHDR_DEST:
108			/* HAO MUST NOT appear more than once.
109			 * XXX: It is better to try to find by the end of
110			 * XXX: packet if HAO exists.
111			 */
112			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
113				net_dbg_ratelimited("mip6: hao exists already, override\n");
114				return offset;
115			}
116
117			if (found_rhdr)
118				return offset;
119
120			break;
121		default:
122			return offset;
123		}
124
125		if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
126			return -EINVAL;
127
128		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
129						 offset);
130		offset += ipv6_optlen(exthdr);
131		if (offset > IPV6_MAXPLEN)
132			return -EINVAL;
133		*nexthdr = &exthdr->nexthdr;
134	}
135
136	return -EINVAL;
137}
138#endif
139
140#if IS_ENABLED(CONFIG_IPV6)
141static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
142{
143	switch (x->type->proto) {
144#if IS_ENABLED(CONFIG_IPV6_MIP6)
145	case IPPROTO_DSTOPTS:
146	case IPPROTO_ROUTING:
147		return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
148#endif
149	default:
150		break;
151	}
152
153	return ip6_find_1stfragopt(skb, prevhdr);
154}
155#endif
156
157/* Add encapsulation header.
158 *
159 * The IP header and mutable extension headers will be moved forward to make
160 * space for the encapsulation header.
161 */
162static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
163{
164#if IS_ENABLED(CONFIG_IPV6)
165	struct ipv6hdr *iph;
166	u8 *prevhdr;
167	int hdr_len;
168
169	iph = ipv6_hdr(skb);
170	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
171
172	hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
173	if (hdr_len < 0)
174		return hdr_len;
175	skb_set_mac_header(skb,
176			   (prevhdr - x->props.header_len) - skb->data);
177	skb_set_network_header(skb, -x->props.header_len);
178	skb->transport_header = skb->network_header + hdr_len;
179	__skb_pull(skb, hdr_len);
180	memmove(ipv6_hdr(skb), iph, hdr_len);
181	return 0;
182#else
183	WARN_ON_ONCE(1);
184	return -EAFNOSUPPORT;
185#endif
186}
187
188/* Add route optimization header space.
189 *
190 * The IP header and mutable extension headers will be moved forward to make
191 * space for the route optimization header.
192 */
193static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
194{
195#if IS_ENABLED(CONFIG_IPV6)
196	struct ipv6hdr *iph;
197	u8 *prevhdr;
198	int hdr_len;
199
200	iph = ipv6_hdr(skb);
201
202	hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
203	if (hdr_len < 0)
204		return hdr_len;
205	skb_set_mac_header(skb,
206			   (prevhdr - x->props.header_len) - skb->data);
207	skb_set_network_header(skb, -x->props.header_len);
208	skb->transport_header = skb->network_header + hdr_len;
209	__skb_pull(skb, hdr_len);
210	memmove(ipv6_hdr(skb), iph, hdr_len);
211
212	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 */
225static 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 */
274static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
275{
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) ?
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)
319static 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
354static 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 */
405static 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->outer_mode.encap) {
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
427static 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->outer_mode.encap) {
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
453static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
454{
455	switch (x->outer_mode.encap) {
456	case XFRM_MODE_BEET:
457	case XFRM_MODE_TUNNEL:
458		if (x->outer_mode.family == AF_INET)
459			return xfrm4_prepare_output(x, skb);
460		if (x->outer_mode.family == AF_INET6)
461			return xfrm6_prepare_output(x, skb);
462		break;
463	case XFRM_MODE_TRANSPORT:
464		if (x->outer_mode.family == AF_INET)
465			return xfrm4_transport_output(x, skb);
466		if (x->outer_mode.family == AF_INET6)
467			return xfrm6_transport_output(x, skb);
468		break;
469	case XFRM_MODE_ROUTEOPTIMIZATION:
470		if (x->outer_mode.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
482#if IS_ENABLED(CONFIG_NET_PKTGEN)
483int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
484{
485	return xfrm_outer_mode_output(x, skb);
486}
487EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
488#endif
489
490static int xfrm_output_one(struct sk_buff *skb, int err)
491{
492	struct dst_entry *dst = skb_dst(skb);
493	struct xfrm_state *x = dst->xfrm;
494	struct net *net = xs_net(x);
495
496	if (err <= 0)
497		goto resume;
498
499	do {
500		err = xfrm_skb_check_space(skb);
501		if (err) {
502			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
503			goto error_nolock;
504		}
505
506		skb->mark = xfrm_smark_get(skb->mark, x);
507
508		err = xfrm_outer_mode_output(x, skb);
509		if (err) {
510			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
511			goto error_nolock;
512		}
513
514		spin_lock_bh(&x->lock);
515
516		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
517			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
518			err = -EINVAL;
519			goto error;
520		}
521
522		err = xfrm_state_check_expire(x);
523		if (err) {
524			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
525			goto error;
526		}
527
528		err = xfrm_replay_overflow(x, skb);
529		if (err) {
530			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
531			goto error;
532		}
533
534		x->curlft.bytes += skb->len;
535		x->curlft.packets++;
536
537		spin_unlock_bh(&x->lock);
538
539		skb_dst_force(skb);
540		if (!skb_dst(skb)) {
541			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
542			err = -EHOSTUNREACH;
543			goto error_nolock;
544		}
545
546		if (xfrm_offload(skb)) {
547			x->type_offload->encap(x, skb);
548		} else {
549			/* Inner headers are invalid now. */
550			skb->encapsulation = 0;
551
552			err = x->type->output(x, skb);
553			if (err == -EINPROGRESS)
554				goto out;
555		}
556
557resume:
558		if (err) {
559			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
560			goto error_nolock;
561		}
562
563		dst = skb_dst_pop(skb);
564		if (!dst) {
565			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
566			err = -EHOSTUNREACH;
567			goto error_nolock;
568		}
569		skb_dst_set(skb, dst);
570		x = dst->xfrm;
571	} while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
572
573	return 0;
574
575error:
576	spin_unlock_bh(&x->lock);
577error_nolock:
578	kfree_skb(skb);
579out:
580	return err;
581}
582
583int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
584{
585	struct net *net = xs_net(skb_dst(skb)->xfrm);
586
587	while (likely((err = xfrm_output_one(skb, err)) == 0)) {
588		nf_reset_ct(skb);
589
590		err = skb_dst(skb)->ops->local_out(net, sk, skb);
591		if (unlikely(err != 1))
592			goto out;
593
594		if (!skb_dst(skb)->xfrm)
595			return dst_output(net, sk, skb);
596
597		err = nf_hook(skb_dst(skb)->ops->family,
598			      NF_INET_POST_ROUTING, net, sk, skb,
599			      NULL, skb_dst(skb)->dev, xfrm_output2);
600		if (unlikely(err != 1))
601			goto out;
602	}
603
604	if (err == -EINPROGRESS)
605		err = 0;
606
607out:
608	return err;
609}
610EXPORT_SYMBOL_GPL(xfrm_output_resume);
611
612static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
613{
614	return xfrm_output_resume(sk, skb, 1);
615}
616
617static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
618{
619	struct sk_buff *segs, *nskb;
620
621	BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
622	BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
623	segs = skb_gso_segment(skb, 0);
624	kfree_skb(skb);
625	if (IS_ERR(segs))
626		return PTR_ERR(segs);
627	if (segs == NULL)
628		return -EINVAL;
629
630	skb_list_walk_safe(segs, segs, nskb) {
 
631		int err;
632
633		skb_mark_not_on_list(segs);
634		err = xfrm_output2(net, sk, segs);
635
636		if (unlikely(err)) {
637			kfree_skb_list(nskb);
638			return err;
639		}
640	}
641
642	return 0;
643}
644
645/* For partial checksum offload, the outer header checksum is calculated
646 * by software and the inner header checksum is calculated by hardware.
647 * This requires hardware to know the inner packet type to calculate
648 * the inner header checksum. Save inner ip protocol here to avoid
649 * traversing the packet in the vendor's xmit code.
650 * If the encap type is IPIP, just save skb->inner_ipproto. Otherwise,
651 * get the ip protocol from the IP header.
652 */
653static void xfrm_get_inner_ipproto(struct sk_buff *skb)
654{
655	struct xfrm_offload *xo = xfrm_offload(skb);
656	const struct ethhdr *eth;
657
658	if (!xo)
659		return;
660
661	if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
662		xo->inner_ipproto = skb->inner_ipproto;
663		return;
664	}
665
666	if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
667		return;
668
669	eth = (struct ethhdr *)skb_inner_mac_header(skb);
670
671	switch (ntohs(eth->h_proto)) {
672	case ETH_P_IPV6:
673		xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
674		break;
675	case ETH_P_IP:
676		xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
677		break;
678	}
679}
680
681int xfrm_output(struct sock *sk, struct sk_buff *skb)
682{
683	struct net *net = dev_net(skb_dst(skb)->dev);
684	struct xfrm_state *x = skb_dst(skb)->xfrm;
685	int err;
686
687	switch (x->outer_mode.family) {
688	case AF_INET:
689		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
690		IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
691		break;
692	case AF_INET6:
693		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
694
695		IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
696		break;
697	}
698
699	secpath_reset(skb);
700
701	if (xfrm_dev_offload_ok(skb, x)) {
702		struct sec_path *sp;
703
704		sp = secpath_set(skb);
705		if (!sp) {
706			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
707			kfree_skb(skb);
708			return -ENOMEM;
709		}
710
711		sp->olen++;
712		sp->xvec[sp->len++] = x;
713		xfrm_state_hold(x);
714
715		if (skb->encapsulation)
716			xfrm_get_inner_ipproto(skb);
717		skb->encapsulation = 1;
718
719		if (skb_is_gso(skb)) {
720			if (skb->inner_protocol)
721				return xfrm_output_gso(net, sk, skb);
722
723			skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
724			goto out;
725		}
726
727		if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
728			goto out;
729	} else {
730		if (skb_is_gso(skb))
731			return xfrm_output_gso(net, sk, skb);
732	}
733
734	if (skb->ip_summed == CHECKSUM_PARTIAL) {
735		err = skb_checksum_help(skb);
736		if (err) {
737			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
738			kfree_skb(skb);
739			return err;
740		}
741	}
742
743out:
744	return xfrm_output2(net, sk, skb);
745}
746EXPORT_SYMBOL_GPL(xfrm_output);
747
748static int xfrm4_tunnel_check_size(struct sk_buff *skb)
749{
750	int mtu, ret = 0;
751
752	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
753		goto out;
754
755	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
756		goto out;
757
758	mtu = dst_mtu(skb_dst(skb));
759	if ((!skb_is_gso(skb) && skb->len > mtu) ||
760	    (skb_is_gso(skb) &&
761	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
762		skb->protocol = htons(ETH_P_IP);
763
764		if (skb->sk)
765			xfrm_local_error(skb, mtu);
766		else
767			icmp_send(skb, ICMP_DEST_UNREACH,
768				  ICMP_FRAG_NEEDED, htonl(mtu));
769		ret = -EMSGSIZE;
770	}
771out:
772	return ret;
773}
774
775static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
776{
777	int err;
778
779	if (x->outer_mode.encap == XFRM_MODE_BEET &&
780	    ip_is_fragment(ip_hdr(skb))) {
781		net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
782		return -EAFNOSUPPORT;
783	}
784
785	err = xfrm4_tunnel_check_size(skb);
786	if (err)
787		return err;
788
789	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
790
791	xfrm4_extract_header(skb);
792	return 0;
793}
794
795#if IS_ENABLED(CONFIG_IPV6)
796static int xfrm6_tunnel_check_size(struct sk_buff *skb)
797{
798	int mtu, ret = 0;
799	struct dst_entry *dst = skb_dst(skb);
800
801	if (skb->ignore_df)
802		goto out;
803
804	mtu = dst_mtu(dst);
805	if (mtu < IPV6_MIN_MTU)
806		mtu = IPV6_MIN_MTU;
807
808	if ((!skb_is_gso(skb) && skb->len > mtu) ||
809	    (skb_is_gso(skb) &&
810	     !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
811		skb->dev = dst->dev;
812		skb->protocol = htons(ETH_P_IPV6);
813
814		if (xfrm6_local_dontfrag(skb->sk))
815			ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
816		else if (skb->sk)
817			xfrm_local_error(skb, mtu);
818		else
819			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
820		ret = -EMSGSIZE;
821	}
822out:
823	return ret;
824}
825#endif
826
827static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
828{
829#if IS_ENABLED(CONFIG_IPV6)
830	int err;
831
832	err = xfrm6_tunnel_check_size(skb);
833	if (err)
834		return err;
835
836	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
837
838	xfrm6_extract_header(skb);
839	return 0;
840#else
841	WARN_ON_ONCE(1);
842	return -EAFNOSUPPORT;
843#endif
844}
845
846static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
847{
848	const struct xfrm_mode *inner_mode;
849
850	if (x->sel.family == AF_UNSPEC)
851		inner_mode = xfrm_ip2inner_mode(x,
852				xfrm_af2proto(skb_dst(skb)->ops->family));
853	else
854		inner_mode = &x->inner_mode;
855
856	if (inner_mode == NULL)
857		return -EAFNOSUPPORT;
858
859	switch (inner_mode->family) {
860	case AF_INET:
861		return xfrm4_extract_output(x, skb);
862	case AF_INET6:
863		return xfrm6_extract_output(x, skb);
864	}
865
866	return -EAFNOSUPPORT;
867}
 
868
869void xfrm_local_error(struct sk_buff *skb, int mtu)
870{
871	unsigned int proto;
872	struct xfrm_state_afinfo *afinfo;
873
874	if (skb->protocol == htons(ETH_P_IP))
875		proto = AF_INET;
876	else if (skb->protocol == htons(ETH_P_IPV6) &&
877		 skb->sk->sk_family == AF_INET6)
878		proto = AF_INET6;
879	else
880		return;
881
882	afinfo = xfrm_state_get_afinfo(proto);
883	if (afinfo) {
884		afinfo->local_error(skb, mtu);
885		rcu_read_unlock();
886	}
 
887}
888EXPORT_SYMBOL_GPL(xfrm_local_error);