1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * SR-IPv6 implementation
4 *
5 * Author:
6 * David Lebrun <david.lebrun@uclouvain.be>
7 */
8
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/net.h>
12 #include <linux/module.h>
13 #include <net/ip.h>
14 #include <net/ip_tunnels.h>
15 #include <net/lwtunnel.h>
16 #include <net/netevent.h>
17 #include <net/netns/generic.h>
18 #include <net/ip6_fib.h>
19 #include <net/route.h>
20 #include <net/seg6.h>
21 #include <linux/seg6.h>
22 #include <linux/seg6_iptunnel.h>
23 #include <net/addrconf.h>
24 #include <net/ip6_route.h>
25 #include <net/dst_cache.h>
26 #ifdef CONFIG_IPV6_SEG6_HMAC
27 #include <net/seg6_hmac.h>
28 #endif
29 #include <linux/netfilter.h>
30
seg6_lwt_headroom(struct seg6_iptunnel_encap * tuninfo)31 static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
32 {
33 int head = 0;
34
35 switch (tuninfo->mode) {
36 case SEG6_IPTUN_MODE_INLINE:
37 break;
38 case SEG6_IPTUN_MODE_ENCAP:
39 case SEG6_IPTUN_MODE_ENCAP_RED:
40 head = sizeof(struct ipv6hdr);
41 break;
42 case SEG6_IPTUN_MODE_L2ENCAP:
43 case SEG6_IPTUN_MODE_L2ENCAP_RED:
44 return 0;
45 }
46
47 return ((tuninfo->srh->hdrlen + 1) << 3) + head;
48 }
49
50 struct seg6_lwt {
51 struct dst_cache cache;
52 struct seg6_iptunnel_encap tuninfo[];
53 };
54
seg6_lwt_lwtunnel(struct lwtunnel_state * lwt)55 static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
56 {
57 return (struct seg6_lwt *)lwt->data;
58 }
59
60 static inline struct seg6_iptunnel_encap *
seg6_encap_lwtunnel(struct lwtunnel_state * lwt)61 seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
62 {
63 return seg6_lwt_lwtunnel(lwt)->tuninfo;
64 }
65
66 static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
67 [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
68 };
69
nla_put_srh(struct sk_buff * skb,int attrtype,struct seg6_iptunnel_encap * tuninfo)70 static int nla_put_srh(struct sk_buff *skb, int attrtype,
71 struct seg6_iptunnel_encap *tuninfo)
72 {
73 struct seg6_iptunnel_encap *data;
74 struct nlattr *nla;
75 int len;
76
77 len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
78
79 nla = nla_reserve(skb, attrtype, len);
80 if (!nla)
81 return -EMSGSIZE;
82
83 data = nla_data(nla);
84 memcpy(data, tuninfo, len);
85
86 return 0;
87 }
88
set_tun_src(struct net * net,struct net_device * dev,struct in6_addr * daddr,struct in6_addr * saddr)89 static void set_tun_src(struct net *net, struct net_device *dev,
90 struct in6_addr *daddr, struct in6_addr *saddr)
91 {
92 struct seg6_pernet_data *sdata = seg6_pernet(net);
93 struct in6_addr *tun_src;
94
95 rcu_read_lock();
96
97 tun_src = rcu_dereference(sdata->tun_src);
98
99 if (!ipv6_addr_any(tun_src)) {
100 memcpy(saddr, tun_src, sizeof(struct in6_addr));
101 } else {
102 ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
103 saddr);
104 }
105
106 rcu_read_unlock();
107 }
108
109 /* Compute flowlabel for outer IPv6 header */
seg6_make_flowlabel(struct net * net,struct sk_buff * skb,struct ipv6hdr * inner_hdr)110 static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
111 struct ipv6hdr *inner_hdr)
112 {
113 int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
114 __be32 flowlabel = 0;
115 u32 hash;
116
117 if (do_flowlabel > 0) {
118 hash = skb_get_hash(skb);
119 hash = rol32(hash, 16);
120 flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
121 } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
122 flowlabel = ip6_flowlabel(inner_hdr);
123 }
124 return flowlabel;
125 }
126
__seg6_do_srh_encap(struct sk_buff * skb,struct ipv6_sr_hdr * osrh,int proto,struct dst_entry * cache_dst)127 static int __seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
128 int proto, struct dst_entry *cache_dst)
129 {
130 struct dst_entry *dst = skb_dst(skb);
131 struct net_device *dev = dst_dev(dst);
132 struct net *net = dev_net(dev);
133 struct ipv6hdr *hdr, *inner_hdr;
134 struct ipv6_sr_hdr *isrh;
135 int hdrlen, tot_len, err;
136 __be32 flowlabel;
137
138 hdrlen = (osrh->hdrlen + 1) << 3;
139 tot_len = hdrlen + sizeof(*hdr);
140
141 err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb));
142 if (unlikely(err))
143 return err;
144
145 inner_hdr = ipv6_hdr(skb);
146 flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
147
148 skb_push(skb, tot_len);
149 skb_reset_network_header(skb);
150 skb_mac_header_rebuild(skb);
151 hdr = ipv6_hdr(skb);
152
153 /* inherit tc, flowlabel and hlim
154 * hlim will be decremented in ip6_forward() afterwards and
155 * decapsulation will overwrite inner hlim with outer hlim
156 */
157
158 if (skb->protocol == htons(ETH_P_IPV6)) {
159 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
160 flowlabel);
161 hdr->hop_limit = inner_hdr->hop_limit;
162 } else {
163 ip6_flow_hdr(hdr, 0, flowlabel);
164 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
165
166 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
167
168 /* the control block has been erased, so we have to set the
169 * iif once again.
170 * We read the receiving interface index directly from the
171 * skb->skb_iif as it is done in the IPv4 receiving path (i.e.:
172 * ip_rcv_core(...)).
173 */
174 IP6CB(skb)->iif = skb->skb_iif;
175 }
176
177 hdr->nexthdr = NEXTHDR_ROUTING;
178
179 isrh = (void *)hdr + sizeof(*hdr);
180 memcpy(isrh, osrh, hdrlen);
181
182 isrh->nexthdr = proto;
183
184 hdr->daddr = isrh->segments[isrh->first_segment];
185 set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
186
187 #ifdef CONFIG_IPV6_SEG6_HMAC
188 if (sr_has_hmac(isrh)) {
189 err = seg6_push_hmac(net, &hdr->saddr, isrh);
190 if (unlikely(err))
191 return err;
192 }
193 #endif
194
195 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
196
197 skb_postpush_rcsum(skb, hdr, tot_len);
198
199 return 0;
200 }
201
202 /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
seg6_do_srh_encap(struct sk_buff * skb,struct ipv6_sr_hdr * osrh,int proto)203 int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
204 {
205 return __seg6_do_srh_encap(skb, osrh, proto, NULL);
206 }
207 EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
208
209 /* encapsulate an IPv6 packet within an outer IPv6 header with reduced SRH */
seg6_do_srh_encap_red(struct sk_buff * skb,struct ipv6_sr_hdr * osrh,int proto,struct dst_entry * cache_dst)210 static int seg6_do_srh_encap_red(struct sk_buff *skb,
211 struct ipv6_sr_hdr *osrh, int proto,
212 struct dst_entry *cache_dst)
213 {
214 __u8 first_seg = osrh->first_segment;
215 struct dst_entry *dst = skb_dst(skb);
216 struct net_device *dev = dst_dev(dst);
217 struct net *net = dev_net(dev);
218 struct ipv6hdr *hdr, *inner_hdr;
219 int hdrlen = ipv6_optlen(osrh);
220 int red_tlv_offset, tlv_offset;
221 struct ipv6_sr_hdr *isrh;
222 bool skip_srh = false;
223 __be32 flowlabel;
224 int tot_len, err;
225 int red_hdrlen;
226 int tlvs_len;
227
228 if (first_seg > 0) {
229 red_hdrlen = hdrlen - sizeof(struct in6_addr);
230 } else {
231 /* NOTE: if tag/flags and/or other TLVs are introduced in the
232 * seg6_iptunnel infrastructure, they should be considered when
233 * deciding to skip the SRH.
234 */
235 skip_srh = !sr_has_hmac(osrh);
236
237 red_hdrlen = skip_srh ? 0 : hdrlen;
238 }
239
240 tot_len = red_hdrlen + sizeof(struct ipv6hdr);
241
242 err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb));
243 if (unlikely(err))
244 return err;
245
246 inner_hdr = ipv6_hdr(skb);
247 flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
248
249 skb_push(skb, tot_len);
250 skb_reset_network_header(skb);
251 skb_mac_header_rebuild(skb);
252 hdr = ipv6_hdr(skb);
253
254 /* based on seg6_do_srh_encap() */
255 if (skb->protocol == htons(ETH_P_IPV6)) {
256 ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
257 flowlabel);
258 hdr->hop_limit = inner_hdr->hop_limit;
259 } else {
260 ip6_flow_hdr(hdr, 0, flowlabel);
261 hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
262
263 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
264 IP6CB(skb)->iif = skb->skb_iif;
265 }
266
267 /* no matter if we have to skip the SRH or not, the first segment
268 * always comes in the pushed IPv6 header.
269 */
270 hdr->daddr = osrh->segments[first_seg];
271
272 if (skip_srh) {
273 hdr->nexthdr = proto;
274
275 set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
276 goto out;
277 }
278
279 /* we cannot skip the SRH, slow path */
280
281 hdr->nexthdr = NEXTHDR_ROUTING;
282 isrh = (void *)hdr + sizeof(struct ipv6hdr);
283
284 if (unlikely(!first_seg)) {
285 /* this is a very rare case; we have only one SID but
286 * we cannot skip the SRH since we are carrying some
287 * other info.
288 */
289 memcpy(isrh, osrh, hdrlen);
290 goto srcaddr;
291 }
292
293 tlv_offset = sizeof(*osrh) + (first_seg + 1) * sizeof(struct in6_addr);
294 red_tlv_offset = tlv_offset - sizeof(struct in6_addr);
295
296 memcpy(isrh, osrh, red_tlv_offset);
297
298 tlvs_len = hdrlen - tlv_offset;
299 if (unlikely(tlvs_len > 0)) {
300 const void *s = (const void *)osrh + tlv_offset;
301 void *d = (void *)isrh + red_tlv_offset;
302
303 memcpy(d, s, tlvs_len);
304 }
305
306 --isrh->first_segment;
307 isrh->hdrlen -= 2;
308
309 srcaddr:
310 isrh->nexthdr = proto;
311 set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
312
313 #ifdef CONFIG_IPV6_SEG6_HMAC
314 if (unlikely(!skip_srh && sr_has_hmac(isrh))) {
315 err = seg6_push_hmac(net, &hdr->saddr, isrh);
316 if (unlikely(err))
317 return err;
318 }
319 #endif
320
321 out:
322 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
323
324 skb_postpush_rcsum(skb, hdr, tot_len);
325
326 return 0;
327 }
328
__seg6_do_srh_inline(struct sk_buff * skb,struct ipv6_sr_hdr * osrh,struct dst_entry * cache_dst)329 static int __seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
330 struct dst_entry *cache_dst)
331 {
332 struct ipv6hdr *hdr, *oldhdr;
333 struct ipv6_sr_hdr *isrh;
334 int hdrlen, err;
335
336 hdrlen = (osrh->hdrlen + 1) << 3;
337
338 err = skb_cow_head(skb, hdrlen + dst_dev_overhead(cache_dst, skb));
339 if (unlikely(err))
340 return err;
341
342 oldhdr = ipv6_hdr(skb);
343
344 skb_pull(skb, sizeof(struct ipv6hdr));
345 skb_postpull_rcsum(skb, skb_network_header(skb),
346 sizeof(struct ipv6hdr));
347
348 skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
349 skb_reset_network_header(skb);
350 skb_mac_header_rebuild(skb);
351
352 hdr = ipv6_hdr(skb);
353
354 memmove(hdr, oldhdr, sizeof(*hdr));
355
356 isrh = (void *)hdr + sizeof(*hdr);
357 memcpy(isrh, osrh, hdrlen);
358
359 isrh->nexthdr = hdr->nexthdr;
360 hdr->nexthdr = NEXTHDR_ROUTING;
361
362 isrh->segments[0] = hdr->daddr;
363 hdr->daddr = isrh->segments[isrh->first_segment];
364
365 #ifdef CONFIG_IPV6_SEG6_HMAC
366 if (sr_has_hmac(isrh)) {
367 struct net *net = skb_dst_dev_net(skb);
368
369 err = seg6_push_hmac(net, &hdr->saddr, isrh);
370 if (unlikely(err))
371 return err;
372 }
373 #endif
374
375 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
376
377 skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
378
379 return 0;
380 }
381
seg6_do_srh(struct sk_buff * skb,struct dst_entry * cache_dst)382 static int seg6_do_srh(struct sk_buff *skb, struct dst_entry *cache_dst)
383 {
384 struct dst_entry *dst = skb_dst(skb);
385 struct seg6_iptunnel_encap *tinfo;
386 int proto, err = 0;
387
388 tinfo = seg6_encap_lwtunnel(dst->lwtstate);
389
390 switch (tinfo->mode) {
391 case SEG6_IPTUN_MODE_INLINE:
392 if (skb->protocol != htons(ETH_P_IPV6))
393 return -EINVAL;
394
395 err = __seg6_do_srh_inline(skb, tinfo->srh, cache_dst);
396 if (err)
397 return err;
398 break;
399 case SEG6_IPTUN_MODE_ENCAP:
400 case SEG6_IPTUN_MODE_ENCAP_RED:
401 err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
402 if (err)
403 return err;
404
405 if (skb->protocol == htons(ETH_P_IPV6))
406 proto = IPPROTO_IPV6;
407 else if (skb->protocol == htons(ETH_P_IP))
408 proto = IPPROTO_IPIP;
409 else
410 return -EINVAL;
411
412 if (tinfo->mode == SEG6_IPTUN_MODE_ENCAP)
413 err = __seg6_do_srh_encap(skb, tinfo->srh,
414 proto, cache_dst);
415 else
416 err = seg6_do_srh_encap_red(skb, tinfo->srh,
417 proto, cache_dst);
418
419 if (err)
420 return err;
421
422 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
423 skb_set_inner_protocol(skb, skb->protocol);
424 skb->protocol = htons(ETH_P_IPV6);
425 break;
426 case SEG6_IPTUN_MODE_L2ENCAP:
427 case SEG6_IPTUN_MODE_L2ENCAP_RED:
428 if (!skb_mac_header_was_set(skb))
429 return -EINVAL;
430
431 if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
432 return -ENOMEM;
433
434 skb_mac_header_rebuild(skb);
435 skb_push(skb, skb->mac_len);
436
437 if (tinfo->mode == SEG6_IPTUN_MODE_L2ENCAP)
438 err = __seg6_do_srh_encap(skb, tinfo->srh,
439 IPPROTO_ETHERNET,
440 cache_dst);
441 else
442 err = seg6_do_srh_encap_red(skb, tinfo->srh,
443 IPPROTO_ETHERNET,
444 cache_dst);
445
446 if (err)
447 return err;
448
449 skb->protocol = htons(ETH_P_IPV6);
450 break;
451 }
452
453 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
454 nf_reset_ct(skb);
455
456 return 0;
457 }
458
459 /* insert an SRH within an IPv6 packet, just after the IPv6 header */
seg6_do_srh_inline(struct sk_buff * skb,struct ipv6_sr_hdr * osrh)460 int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
461 {
462 return __seg6_do_srh_inline(skb, osrh, NULL);
463 }
464 EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
465
seg6_input_finish(struct net * net,struct sock * sk,struct sk_buff * skb)466 static int seg6_input_finish(struct net *net, struct sock *sk,
467 struct sk_buff *skb)
468 {
469 return dst_input(skb);
470 }
471
seg6_input_core(struct net * net,struct sock * sk,struct sk_buff * skb)472 static int seg6_input_core(struct net *net, struct sock *sk,
473 struct sk_buff *skb)
474 {
475 struct dst_entry *orig_dst = skb_dst(skb);
476 struct dst_entry *dst = NULL;
477 struct lwtunnel_state *lwtst;
478 struct seg6_lwt *slwt;
479 int err;
480
481 /* We cannot dereference "orig_dst" once ip6_route_input() or
482 * skb_dst_drop() is called. However, in order to detect a dst loop, we
483 * need the address of its lwtstate. So, save the address of lwtstate
484 * now and use it later as a comparison.
485 */
486 lwtst = orig_dst->lwtstate;
487
488 slwt = seg6_lwt_lwtunnel(lwtst);
489
490 local_bh_disable();
491 dst = dst_cache_get(&slwt->cache);
492 local_bh_enable();
493
494 err = seg6_do_srh(skb, dst);
495 if (unlikely(err)) {
496 dst_release(dst);
497 goto drop;
498 }
499
500 if (!dst) {
501 ip6_route_input(skb);
502 dst = skb_dst(skb);
503
504 /* cache only if we don't create a dst reference loop */
505 if (!dst->error && lwtst != dst->lwtstate) {
506 local_bh_disable();
507 dst_cache_set_ip6(&slwt->cache, dst,
508 &ipv6_hdr(skb)->saddr);
509 local_bh_enable();
510 }
511
512 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
513 if (unlikely(err))
514 goto drop;
515 } else {
516 skb_dst_drop(skb);
517 skb_dst_set(skb, dst);
518 }
519
520 if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
521 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
522 dev_net(skb->dev), NULL, skb, NULL,
523 skb_dst_dev(skb), seg6_input_finish);
524
525 return seg6_input_finish(dev_net(skb->dev), NULL, skb);
526 drop:
527 kfree_skb(skb);
528 return err;
529 }
530
seg6_input_nf(struct sk_buff * skb)531 static int seg6_input_nf(struct sk_buff *skb)
532 {
533 struct net_device *dev = skb_dst_dev(skb);
534 struct net *net = dev_net(skb->dev);
535
536 switch (skb->protocol) {
537 case htons(ETH_P_IP):
538 return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, NULL,
539 skb, NULL, dev, seg6_input_core);
540 case htons(ETH_P_IPV6):
541 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, NULL,
542 skb, NULL, dev, seg6_input_core);
543 }
544
545 return -EINVAL;
546 }
547
seg6_input(struct sk_buff * skb)548 static int seg6_input(struct sk_buff *skb)
549 {
550 if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
551 return seg6_input_nf(skb);
552
553 return seg6_input_core(dev_net(skb->dev), NULL, skb);
554 }
555
seg6_output_core(struct net * net,struct sock * sk,struct sk_buff * skb)556 static int seg6_output_core(struct net *net, struct sock *sk,
557 struct sk_buff *skb)
558 {
559 struct dst_entry *orig_dst = skb_dst(skb);
560 struct dst_entry *dst = NULL;
561 struct seg6_lwt *slwt;
562 int err;
563
564 slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
565
566 local_bh_disable();
567 dst = dst_cache_get(&slwt->cache);
568 local_bh_enable();
569
570 err = seg6_do_srh(skb, dst);
571 if (unlikely(err))
572 goto drop;
573
574 if (unlikely(!dst)) {
575 struct ipv6hdr *hdr = ipv6_hdr(skb);
576 struct flowi6 fl6;
577
578 memset(&fl6, 0, sizeof(fl6));
579 fl6.daddr = hdr->daddr;
580 fl6.saddr = hdr->saddr;
581 fl6.flowlabel = ip6_flowinfo(hdr);
582 fl6.flowi6_mark = skb->mark;
583 fl6.flowi6_proto = hdr->nexthdr;
584
585 dst = ip6_route_output(net, NULL, &fl6);
586 if (dst->error) {
587 err = dst->error;
588 goto drop;
589 }
590
591 /* cache only if we don't create a dst reference loop */
592 if (orig_dst->lwtstate != dst->lwtstate) {
593 local_bh_disable();
594 dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
595 local_bh_enable();
596 }
597
598 err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
599 if (unlikely(err))
600 goto drop;
601 }
602
603 skb_dst_drop(skb);
604 skb_dst_set(skb, dst);
605
606 if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
607 return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
608 NULL, dst_dev(dst), dst_output);
609
610 return dst_output(net, sk, skb);
611 drop:
612 dst_release(dst);
613 kfree_skb(skb);
614 return err;
615 }
616
seg6_output_nf(struct net * net,struct sock * sk,struct sk_buff * skb)617 static int seg6_output_nf(struct net *net, struct sock *sk, struct sk_buff *skb)
618 {
619 struct net_device *dev = skb_dst_dev(skb);
620
621 switch (skb->protocol) {
622 case htons(ETH_P_IP):
623 return NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING, net, sk, skb,
624 NULL, dev, seg6_output_core);
625 case htons(ETH_P_IPV6):
626 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, net, sk, skb,
627 NULL, dev, seg6_output_core);
628 }
629
630 return -EINVAL;
631 }
632
seg6_output(struct net * net,struct sock * sk,struct sk_buff * skb)633 static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
634 {
635 if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
636 return seg6_output_nf(net, sk, skb);
637
638 return seg6_output_core(net, sk, skb);
639 }
640
seg6_build_state(struct net * net,struct nlattr * nla,unsigned int family,const void * cfg,struct lwtunnel_state ** ts,struct netlink_ext_ack * extack)641 static int seg6_build_state(struct net *net, struct nlattr *nla,
642 unsigned int family, const void *cfg,
643 struct lwtunnel_state **ts,
644 struct netlink_ext_ack *extack)
645 {
646 struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
647 struct seg6_iptunnel_encap *tuninfo;
648 struct lwtunnel_state *newts;
649 int tuninfo_len, min_size;
650 struct seg6_lwt *slwt;
651 int err;
652
653 if (family != AF_INET && family != AF_INET6)
654 return -EINVAL;
655
656 err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
657 seg6_iptunnel_policy, extack);
658
659 if (err < 0)
660 return err;
661
662 if (!tb[SEG6_IPTUNNEL_SRH])
663 return -EINVAL;
664
665 tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
666 tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
667
668 /* tuninfo must contain at least the iptunnel encap structure,
669 * the SRH and one segment
670 */
671 min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
672 sizeof(struct in6_addr);
673 if (tuninfo_len < min_size)
674 return -EINVAL;
675
676 switch (tuninfo->mode) {
677 case SEG6_IPTUN_MODE_INLINE:
678 if (family != AF_INET6)
679 return -EINVAL;
680
681 break;
682 case SEG6_IPTUN_MODE_ENCAP:
683 break;
684 case SEG6_IPTUN_MODE_L2ENCAP:
685 break;
686 case SEG6_IPTUN_MODE_ENCAP_RED:
687 break;
688 case SEG6_IPTUN_MODE_L2ENCAP_RED:
689 break;
690 default:
691 return -EINVAL;
692 }
693
694 /* verify that SRH is consistent */
695 if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
696 return -EINVAL;
697
698 newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
699 if (!newts)
700 return -ENOMEM;
701
702 slwt = seg6_lwt_lwtunnel(newts);
703
704 err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
705 if (err) {
706 kfree(newts);
707 return err;
708 }
709
710 memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
711
712 newts->type = LWTUNNEL_ENCAP_SEG6;
713 newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
714
715 if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
716 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
717
718 newts->headroom = seg6_lwt_headroom(tuninfo);
719
720 *ts = newts;
721
722 return 0;
723 }
724
seg6_destroy_state(struct lwtunnel_state * lwt)725 static void seg6_destroy_state(struct lwtunnel_state *lwt)
726 {
727 dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
728 }
729
seg6_fill_encap_info(struct sk_buff * skb,struct lwtunnel_state * lwtstate)730 static int seg6_fill_encap_info(struct sk_buff *skb,
731 struct lwtunnel_state *lwtstate)
732 {
733 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
734
735 if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
736 return -EMSGSIZE;
737
738 return 0;
739 }
740
seg6_encap_nlsize(struct lwtunnel_state * lwtstate)741 static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
742 {
743 struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
744
745 return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
746 }
747
seg6_encap_cmp(struct lwtunnel_state * a,struct lwtunnel_state * b)748 static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
749 {
750 struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
751 struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
752 int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
753
754 if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
755 return 1;
756
757 return memcmp(a_hdr, b_hdr, len);
758 }
759
760 static const struct lwtunnel_encap_ops seg6_iptun_ops = {
761 .build_state = seg6_build_state,
762 .destroy_state = seg6_destroy_state,
763 .output = seg6_output,
764 .input = seg6_input,
765 .fill_encap = seg6_fill_encap_info,
766 .get_encap_size = seg6_encap_nlsize,
767 .cmp_encap = seg6_encap_cmp,
768 .owner = THIS_MODULE,
769 };
770
seg6_iptunnel_init(void)771 int __init seg6_iptunnel_init(void)
772 {
773 return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
774 }
775
seg6_iptunnel_exit(void)776 void seg6_iptunnel_exit(void)
777 {
778 lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
779 }
780