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