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Commit | Line | Data |
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6c8702c6 DL |
1 | /* |
2 | * SR-IPv6 implementation | |
3 | * | |
4 | * Author: | |
5 | * David Lebrun <david.lebrun@uclouvain.be> | |
6 | * | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
12 | */ | |
13 | ||
14 | #include <linux/types.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/net.h> | |
17 | #include <linux/module.h> | |
18 | #include <net/ip.h> | |
19 | #include <net/lwtunnel.h> | |
20 | #include <net/netevent.h> | |
21 | #include <net/netns/generic.h> | |
22 | #include <net/ip6_fib.h> | |
23 | #include <net/route.h> | |
24 | #include <net/seg6.h> | |
25 | #include <linux/seg6.h> | |
26 | #include <linux/seg6_iptunnel.h> | |
27 | #include <net/addrconf.h> | |
28 | #include <net/ip6_route.h> | |
6c8702c6 | 29 | #include <net/dst_cache.h> |
9baee834 DL |
30 | #ifdef CONFIG_IPV6_SEG6_HMAC |
31 | #include <net/seg6_hmac.h> | |
32 | #endif | |
6c8702c6 DL |
33 | |
34 | struct seg6_lwt { | |
6c8702c6 | 35 | struct dst_cache cache; |
6c8702c6 DL |
36 | struct seg6_iptunnel_encap tuninfo[0]; |
37 | }; | |
38 | ||
39 | static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt) | |
40 | { | |
41 | return (struct seg6_lwt *)lwt->data; | |
42 | } | |
43 | ||
44 | static inline struct seg6_iptunnel_encap * | |
45 | seg6_encap_lwtunnel(struct lwtunnel_state *lwt) | |
46 | { | |
47 | return seg6_lwt_lwtunnel(lwt)->tuninfo; | |
48 | } | |
49 | ||
50 | static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = { | |
51 | [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY }, | |
52 | }; | |
53 | ||
bb4005ba WY |
54 | static int nla_put_srh(struct sk_buff *skb, int attrtype, |
55 | struct seg6_iptunnel_encap *tuninfo) | |
6c8702c6 DL |
56 | { |
57 | struct seg6_iptunnel_encap *data; | |
58 | struct nlattr *nla; | |
59 | int len; | |
60 | ||
61 | len = SEG6_IPTUN_ENCAP_SIZE(tuninfo); | |
62 | ||
63 | nla = nla_reserve(skb, attrtype, len); | |
64 | if (!nla) | |
65 | return -EMSGSIZE; | |
66 | ||
67 | data = nla_data(nla); | |
68 | memcpy(data, tuninfo, len); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | static void set_tun_src(struct net *net, struct net_device *dev, | |
74 | struct in6_addr *daddr, struct in6_addr *saddr) | |
75 | { | |
76 | struct seg6_pernet_data *sdata = seg6_pernet(net); | |
77 | struct in6_addr *tun_src; | |
78 | ||
79 | rcu_read_lock(); | |
80 | ||
81 | tun_src = rcu_dereference(sdata->tun_src); | |
82 | ||
83 | if (!ipv6_addr_any(tun_src)) { | |
84 | memcpy(saddr, tun_src, sizeof(struct in6_addr)); | |
85 | } else { | |
86 | ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC, | |
87 | saddr); | |
88 | } | |
89 | ||
90 | rcu_read_unlock(); | |
91 | } | |
92 | ||
93 | /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */ | |
32d99d0b | 94 | int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) |
6c8702c6 DL |
95 | { |
96 | struct net *net = dev_net(skb_dst(skb)->dev); | |
97 | struct ipv6hdr *hdr, *inner_hdr; | |
98 | struct ipv6_sr_hdr *isrh; | |
99 | int hdrlen, tot_len, err; | |
100 | ||
101 | hdrlen = (osrh->hdrlen + 1) << 3; | |
102 | tot_len = hdrlen + sizeof(*hdr); | |
103 | ||
19d5a26f | 104 | err = skb_cow_head(skb, tot_len); |
6c8702c6 DL |
105 | if (unlikely(err)) |
106 | return err; | |
107 | ||
108 | inner_hdr = ipv6_hdr(skb); | |
109 | ||
110 | skb_push(skb, tot_len); | |
111 | skb_reset_network_header(skb); | |
112 | skb_mac_header_rebuild(skb); | |
113 | hdr = ipv6_hdr(skb); | |
114 | ||
115 | /* inherit tc, flowlabel and hlim | |
116 | * hlim will be decremented in ip6_forward() afterwards and | |
117 | * decapsulation will overwrite inner hlim with outer hlim | |
118 | */ | |
32d99d0b DL |
119 | |
120 | if (skb->protocol == htons(ETH_P_IPV6)) { | |
121 | ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)), | |
122 | ip6_flowlabel(inner_hdr)); | |
123 | hdr->hop_limit = inner_hdr->hop_limit; | |
124 | } else { | |
125 | ip6_flow_hdr(hdr, 0, 0); | |
126 | hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb)); | |
127 | } | |
128 | ||
6c8702c6 DL |
129 | hdr->nexthdr = NEXTHDR_ROUTING; |
130 | ||
131 | isrh = (void *)hdr + sizeof(*hdr); | |
132 | memcpy(isrh, osrh, hdrlen); | |
133 | ||
32d99d0b | 134 | isrh->nexthdr = proto; |
6c8702c6 DL |
135 | |
136 | hdr->daddr = isrh->segments[isrh->first_segment]; | |
137 | set_tun_src(net, skb->dev, &hdr->daddr, &hdr->saddr); | |
138 | ||
9baee834 DL |
139 | #ifdef CONFIG_IPV6_SEG6_HMAC |
140 | if (sr_has_hmac(isrh)) { | |
141 | err = seg6_push_hmac(net, &hdr->saddr, isrh); | |
142 | if (unlikely(err)) | |
143 | return err; | |
144 | } | |
145 | #endif | |
146 | ||
6c8702c6 DL |
147 | skb_postpush_rcsum(skb, hdr, tot_len); |
148 | ||
149 | return 0; | |
150 | } | |
b04c80d3 | 151 | EXPORT_SYMBOL_GPL(seg6_do_srh_encap); |
6c8702c6 DL |
152 | |
153 | /* insert an SRH within an IPv6 packet, just after the IPv6 header */ | |
b04c80d3 | 154 | int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) |
6c8702c6 DL |
155 | { |
156 | struct ipv6hdr *hdr, *oldhdr; | |
157 | struct ipv6_sr_hdr *isrh; | |
158 | int hdrlen, err; | |
159 | ||
160 | hdrlen = (osrh->hdrlen + 1) << 3; | |
161 | ||
19d5a26f | 162 | err = skb_cow_head(skb, hdrlen); |
6c8702c6 DL |
163 | if (unlikely(err)) |
164 | return err; | |
165 | ||
166 | oldhdr = ipv6_hdr(skb); | |
167 | ||
168 | skb_pull(skb, sizeof(struct ipv6hdr)); | |
169 | skb_postpull_rcsum(skb, skb_network_header(skb), | |
170 | sizeof(struct ipv6hdr)); | |
171 | ||
172 | skb_push(skb, sizeof(struct ipv6hdr) + hdrlen); | |
173 | skb_reset_network_header(skb); | |
174 | skb_mac_header_rebuild(skb); | |
175 | ||
176 | hdr = ipv6_hdr(skb); | |
177 | ||
178 | memmove(hdr, oldhdr, sizeof(*hdr)); | |
179 | ||
180 | isrh = (void *)hdr + sizeof(*hdr); | |
181 | memcpy(isrh, osrh, hdrlen); | |
182 | ||
183 | isrh->nexthdr = hdr->nexthdr; | |
184 | hdr->nexthdr = NEXTHDR_ROUTING; | |
185 | ||
186 | isrh->segments[0] = hdr->daddr; | |
187 | hdr->daddr = isrh->segments[isrh->first_segment]; | |
188 | ||
9baee834 DL |
189 | #ifdef CONFIG_IPV6_SEG6_HMAC |
190 | if (sr_has_hmac(isrh)) { | |
191 | struct net *net = dev_net(skb_dst(skb)->dev); | |
192 | ||
193 | err = seg6_push_hmac(net, &hdr->saddr, isrh); | |
194 | if (unlikely(err)) | |
195 | return err; | |
196 | } | |
197 | #endif | |
198 | ||
6c8702c6 DL |
199 | skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen); |
200 | ||
201 | return 0; | |
202 | } | |
b04c80d3 | 203 | EXPORT_SYMBOL_GPL(seg6_do_srh_inline); |
6c8702c6 DL |
204 | |
205 | static int seg6_do_srh(struct sk_buff *skb) | |
206 | { | |
207 | struct dst_entry *dst = skb_dst(skb); | |
208 | struct seg6_iptunnel_encap *tinfo; | |
32d99d0b | 209 | int proto, err = 0; |
6c8702c6 DL |
210 | |
211 | tinfo = seg6_encap_lwtunnel(dst->lwtstate); | |
212 | ||
213 | if (likely(!skb->encapsulation)) { | |
214 | skb_reset_inner_headers(skb); | |
215 | skb->encapsulation = 1; | |
216 | } | |
217 | ||
218 | switch (tinfo->mode) { | |
6c8702c6 | 219 | case SEG6_IPTUN_MODE_INLINE: |
32d99d0b DL |
220 | if (skb->protocol != htons(ETH_P_IPV6)) |
221 | return -EINVAL; | |
222 | ||
6c8702c6 | 223 | err = seg6_do_srh_inline(skb, tinfo->srh); |
32d99d0b DL |
224 | if (err) |
225 | return err; | |
226 | ||
6c8702c6 DL |
227 | skb_reset_inner_headers(skb); |
228 | break; | |
6c8702c6 | 229 | case SEG6_IPTUN_MODE_ENCAP: |
32d99d0b DL |
230 | if (skb->protocol == htons(ETH_P_IPV6)) |
231 | proto = IPPROTO_IPV6; | |
232 | else if (skb->protocol == htons(ETH_P_IP)) | |
233 | proto = IPPROTO_IPIP; | |
234 | else | |
235 | return -EINVAL; | |
236 | ||
237 | err = seg6_do_srh_encap(skb, tinfo->srh, proto); | |
238 | if (err) | |
239 | return err; | |
240 | ||
38ee7f2d DL |
241 | skb->protocol = htons(ETH_P_IPV6); |
242 | break; | |
243 | case SEG6_IPTUN_MODE_L2ENCAP: | |
244 | if (!skb_mac_header_was_set(skb)) | |
245 | return -EINVAL; | |
246 | ||
247 | if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0) | |
248 | return -ENOMEM; | |
249 | ||
250 | skb_mac_header_rebuild(skb); | |
251 | skb_push(skb, skb->mac_len); | |
252 | ||
253 | err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE); | |
254 | if (err) | |
255 | return err; | |
256 | ||
32d99d0b | 257 | skb->protocol = htons(ETH_P_IPV6); |
6c8702c6 DL |
258 | break; |
259 | } | |
260 | ||
6c8702c6 DL |
261 | ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); |
262 | skb_set_transport_header(skb, sizeof(struct ipv6hdr)); | |
263 | ||
264 | skb_set_inner_protocol(skb, skb->protocol); | |
265 | ||
266 | return 0; | |
267 | } | |
268 | ||
bb4005ba | 269 | static int seg6_input(struct sk_buff *skb) |
6c8702c6 | 270 | { |
af4a2209 DL |
271 | struct dst_entry *orig_dst = skb_dst(skb); |
272 | struct dst_entry *dst = NULL; | |
273 | struct seg6_lwt *slwt; | |
6c8702c6 DL |
274 | int err; |
275 | ||
276 | err = seg6_do_srh(skb); | |
277 | if (unlikely(err)) { | |
278 | kfree_skb(skb); | |
279 | return err; | |
280 | } | |
281 | ||
af4a2209 DL |
282 | slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); |
283 | ||
af4a2209 DL |
284 | preempt_disable(); |
285 | dst = dst_cache_get(&slwt->cache); | |
286 | preempt_enable(); | |
af4a2209 | 287 | |
6c8702c6 | 288 | skb_dst_drop(skb); |
af4a2209 DL |
289 | |
290 | if (!dst) { | |
291 | ip6_route_input(skb); | |
af4a2209 DL |
292 | dst = skb_dst(skb); |
293 | if (!dst->error) { | |
294 | preempt_disable(); | |
295 | dst_cache_set_ip6(&slwt->cache, dst, | |
296 | &ipv6_hdr(skb)->saddr); | |
297 | preempt_enable(); | |
298 | } | |
af4a2209 DL |
299 | } else { |
300 | skb_dst_set(skb, dst); | |
301 | } | |
6c8702c6 | 302 | |
af3b5158 DL |
303 | err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); |
304 | if (unlikely(err)) | |
305 | return err; | |
306 | ||
6c8702c6 DL |
307 | return dst_input(skb); |
308 | } | |
309 | ||
bb4005ba | 310 | static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
6c8702c6 DL |
311 | { |
312 | struct dst_entry *orig_dst = skb_dst(skb); | |
313 | struct dst_entry *dst = NULL; | |
314 | struct seg6_lwt *slwt; | |
315 | int err = -EINVAL; | |
316 | ||
317 | err = seg6_do_srh(skb); | |
318 | if (unlikely(err)) | |
319 | goto drop; | |
320 | ||
321 | slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); | |
322 | ||
fa79581e | 323 | preempt_disable(); |
6c8702c6 | 324 | dst = dst_cache_get(&slwt->cache); |
fa79581e | 325 | preempt_enable(); |
6c8702c6 DL |
326 | |
327 | if (unlikely(!dst)) { | |
328 | struct ipv6hdr *hdr = ipv6_hdr(skb); | |
329 | struct flowi6 fl6; | |
330 | ||
331 | fl6.daddr = hdr->daddr; | |
332 | fl6.saddr = hdr->saddr; | |
333 | fl6.flowlabel = ip6_flowinfo(hdr); | |
334 | fl6.flowi6_mark = skb->mark; | |
335 | fl6.flowi6_proto = hdr->nexthdr; | |
336 | ||
337 | dst = ip6_route_output(net, NULL, &fl6); | |
338 | if (dst->error) { | |
339 | err = dst->error; | |
340 | dst_release(dst); | |
341 | goto drop; | |
342 | } | |
343 | ||
fa79581e | 344 | preempt_disable(); |
6c8702c6 | 345 | dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr); |
fa79581e | 346 | preempt_enable(); |
6c8702c6 DL |
347 | } |
348 | ||
349 | skb_dst_drop(skb); | |
350 | skb_dst_set(skb, dst); | |
351 | ||
af3b5158 DL |
352 | err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); |
353 | if (unlikely(err)) | |
354 | goto drop; | |
355 | ||
6c8702c6 DL |
356 | return dst_output(net, sk, skb); |
357 | drop: | |
358 | kfree_skb(skb); | |
359 | return err; | |
360 | } | |
361 | ||
30357d7d | 362 | static int seg6_build_state(struct nlattr *nla, |
6c8702c6 | 363 | unsigned int family, const void *cfg, |
9ae28727 DA |
364 | struct lwtunnel_state **ts, |
365 | struct netlink_ext_ack *extack) | |
6c8702c6 DL |
366 | { |
367 | struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1]; | |
368 | struct seg6_iptunnel_encap *tuninfo; | |
369 | struct lwtunnel_state *newts; | |
370 | int tuninfo_len, min_size; | |
371 | struct seg6_lwt *slwt; | |
372 | int err; | |
373 | ||
32d99d0b DL |
374 | if (family != AF_INET && family != AF_INET6) |
375 | return -EINVAL; | |
376 | ||
6c8702c6 | 377 | err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla, |
9ae28727 | 378 | seg6_iptunnel_policy, extack); |
6c8702c6 DL |
379 | |
380 | if (err < 0) | |
381 | return err; | |
382 | ||
383 | if (!tb[SEG6_IPTUNNEL_SRH]) | |
384 | return -EINVAL; | |
385 | ||
386 | tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]); | |
387 | tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]); | |
388 | ||
389 | /* tuninfo must contain at least the iptunnel encap structure, | |
390 | * the SRH and one segment | |
391 | */ | |
392 | min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) + | |
393 | sizeof(struct in6_addr); | |
394 | if (tuninfo_len < min_size) | |
395 | return -EINVAL; | |
396 | ||
397 | switch (tuninfo->mode) { | |
6c8702c6 | 398 | case SEG6_IPTUN_MODE_INLINE: |
32d99d0b DL |
399 | if (family != AF_INET6) |
400 | return -EINVAL; | |
401 | ||
6c8702c6 | 402 | break; |
6c8702c6 DL |
403 | case SEG6_IPTUN_MODE_ENCAP: |
404 | break; | |
38ee7f2d DL |
405 | case SEG6_IPTUN_MODE_L2ENCAP: |
406 | break; | |
6c8702c6 DL |
407 | default: |
408 | return -EINVAL; | |
409 | } | |
410 | ||
411 | /* verify that SRH is consistent */ | |
412 | if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo))) | |
413 | return -EINVAL; | |
414 | ||
415 | newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt)); | |
416 | if (!newts) | |
417 | return -ENOMEM; | |
418 | ||
419 | slwt = seg6_lwt_lwtunnel(newts); | |
420 | ||
6c8702c6 DL |
421 | err = dst_cache_init(&slwt->cache, GFP_KERNEL); |
422 | if (err) { | |
423 | kfree(newts); | |
424 | return err; | |
425 | } | |
6c8702c6 DL |
426 | |
427 | memcpy(&slwt->tuninfo, tuninfo, tuninfo_len); | |
428 | ||
429 | newts->type = LWTUNNEL_ENCAP_SEG6; | |
38ee7f2d DL |
430 | newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT; |
431 | ||
432 | if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP) | |
433 | newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; | |
434 | ||
6c8702c6 DL |
435 | newts->headroom = seg6_lwt_headroom(tuninfo); |
436 | ||
437 | *ts = newts; | |
438 | ||
439 | return 0; | |
440 | } | |
441 | ||
6c8702c6 DL |
442 | static void seg6_destroy_state(struct lwtunnel_state *lwt) |
443 | { | |
444 | dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache); | |
445 | } | |
6c8702c6 DL |
446 | |
447 | static int seg6_fill_encap_info(struct sk_buff *skb, | |
448 | struct lwtunnel_state *lwtstate) | |
449 | { | |
450 | struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate); | |
451 | ||
452 | if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo)) | |
453 | return -EMSGSIZE; | |
454 | ||
455 | return 0; | |
456 | } | |
457 | ||
458 | static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate) | |
459 | { | |
460 | struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate); | |
461 | ||
462 | return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo)); | |
463 | } | |
464 | ||
465 | static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) | |
466 | { | |
467 | struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a); | |
468 | struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b); | |
469 | int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr); | |
470 | ||
471 | if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr)) | |
472 | return 1; | |
473 | ||
474 | return memcmp(a_hdr, b_hdr, len); | |
475 | } | |
476 | ||
477 | static const struct lwtunnel_encap_ops seg6_iptun_ops = { | |
478 | .build_state = seg6_build_state, | |
6c8702c6 | 479 | .destroy_state = seg6_destroy_state, |
6c8702c6 DL |
480 | .output = seg6_output, |
481 | .input = seg6_input, | |
482 | .fill_encap = seg6_fill_encap_info, | |
483 | .get_encap_size = seg6_encap_nlsize, | |
484 | .cmp_encap = seg6_encap_cmp, | |
88ff7334 | 485 | .owner = THIS_MODULE, |
6c8702c6 DL |
486 | }; |
487 | ||
488 | int __init seg6_iptunnel_init(void) | |
489 | { | |
490 | return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6); | |
491 | } | |
492 | ||
493 | void seg6_iptunnel_exit(void) | |
494 | { | |
495 | lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6); | |
496 | } |