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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> | |
5807b22c | 19 | #include <net/ip_tunnels.h> |
6c8702c6 DL |
20 | #include <net/lwtunnel.h> |
21 | #include <net/netevent.h> | |
22 | #include <net/netns/generic.h> | |
23 | #include <net/ip6_fib.h> | |
24 | #include <net/route.h> | |
25 | #include <net/seg6.h> | |
26 | #include <linux/seg6.h> | |
27 | #include <linux/seg6_iptunnel.h> | |
28 | #include <net/addrconf.h> | |
29 | #include <net/ip6_route.h> | |
6c8702c6 | 30 | #include <net/dst_cache.h> |
9baee834 DL |
31 | #ifdef CONFIG_IPV6_SEG6_HMAC |
32 | #include <net/seg6_hmac.h> | |
33 | #endif | |
6c8702c6 DL |
34 | |
35 | struct seg6_lwt { | |
6c8702c6 | 36 | struct dst_cache cache; |
6c8702c6 DL |
37 | struct seg6_iptunnel_encap tuninfo[0]; |
38 | }; | |
39 | ||
40 | static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt) | |
41 | { | |
42 | return (struct seg6_lwt *)lwt->data; | |
43 | } | |
44 | ||
45 | static inline struct seg6_iptunnel_encap * | |
46 | seg6_encap_lwtunnel(struct lwtunnel_state *lwt) | |
47 | { | |
48 | return seg6_lwt_lwtunnel(lwt)->tuninfo; | |
49 | } | |
50 | ||
51 | static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = { | |
52 | [SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY }, | |
53 | }; | |
54 | ||
bb4005ba WY |
55 | static int nla_put_srh(struct sk_buff *skb, int attrtype, |
56 | struct seg6_iptunnel_encap *tuninfo) | |
6c8702c6 DL |
57 | { |
58 | struct seg6_iptunnel_encap *data; | |
59 | struct nlattr *nla; | |
60 | int len; | |
61 | ||
62 | len = SEG6_IPTUN_ENCAP_SIZE(tuninfo); | |
63 | ||
64 | nla = nla_reserve(skb, attrtype, len); | |
65 | if (!nla) | |
66 | return -EMSGSIZE; | |
67 | ||
68 | data = nla_data(nla); | |
69 | memcpy(data, tuninfo, len); | |
70 | ||
71 | return 0; | |
72 | } | |
73 | ||
74 | static void set_tun_src(struct net *net, struct net_device *dev, | |
75 | struct in6_addr *daddr, struct in6_addr *saddr) | |
76 | { | |
77 | struct seg6_pernet_data *sdata = seg6_pernet(net); | |
78 | struct in6_addr *tun_src; | |
79 | ||
80 | rcu_read_lock(); | |
81 | ||
82 | tun_src = rcu_dereference(sdata->tun_src); | |
83 | ||
84 | if (!ipv6_addr_any(tun_src)) { | |
85 | memcpy(saddr, tun_src, sizeof(struct in6_addr)); | |
86 | } else { | |
87 | ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC, | |
88 | saddr); | |
89 | } | |
90 | ||
91 | rcu_read_unlock(); | |
92 | } | |
93 | ||
94 | /* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */ | |
32d99d0b | 95 | int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) |
6c8702c6 | 96 | { |
8936ef76 DL |
97 | struct dst_entry *dst = skb_dst(skb); |
98 | struct net *net = dev_net(dst->dev); | |
6c8702c6 DL |
99 | struct ipv6hdr *hdr, *inner_hdr; |
100 | struct ipv6_sr_hdr *isrh; | |
101 | int hdrlen, tot_len, err; | |
102 | ||
103 | hdrlen = (osrh->hdrlen + 1) << 3; | |
104 | tot_len = hdrlen + sizeof(*hdr); | |
105 | ||
19d5a26f | 106 | err = skb_cow_head(skb, tot_len); |
6c8702c6 DL |
107 | if (unlikely(err)) |
108 | return err; | |
109 | ||
110 | inner_hdr = ipv6_hdr(skb); | |
111 | ||
112 | skb_push(skb, tot_len); | |
113 | skb_reset_network_header(skb); | |
114 | skb_mac_header_rebuild(skb); | |
115 | hdr = ipv6_hdr(skb); | |
116 | ||
117 | /* inherit tc, flowlabel and hlim | |
118 | * hlim will be decremented in ip6_forward() afterwards and | |
119 | * decapsulation will overwrite inner hlim with outer hlim | |
120 | */ | |
32d99d0b DL |
121 | |
122 | if (skb->protocol == htons(ETH_P_IPV6)) { | |
123 | ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)), | |
124 | ip6_flowlabel(inner_hdr)); | |
125 | hdr->hop_limit = inner_hdr->hop_limit; | |
126 | } else { | |
127 | ip6_flow_hdr(hdr, 0, 0); | |
128 | hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb)); | |
129 | } | |
130 | ||
6c8702c6 DL |
131 | hdr->nexthdr = NEXTHDR_ROUTING; |
132 | ||
133 | isrh = (void *)hdr + sizeof(*hdr); | |
134 | memcpy(isrh, osrh, hdrlen); | |
135 | ||
32d99d0b | 136 | isrh->nexthdr = proto; |
6c8702c6 DL |
137 | |
138 | hdr->daddr = isrh->segments[isrh->first_segment]; | |
8936ef76 | 139 | set_tun_src(net, ip6_dst_idev(dst)->dev, &hdr->daddr, &hdr->saddr); |
6c8702c6 | 140 | |
9baee834 DL |
141 | #ifdef CONFIG_IPV6_SEG6_HMAC |
142 | if (sr_has_hmac(isrh)) { | |
143 | err = seg6_push_hmac(net, &hdr->saddr, isrh); | |
144 | if (unlikely(err)) | |
145 | return err; | |
146 | } | |
147 | #endif | |
148 | ||
6c8702c6 DL |
149 | skb_postpush_rcsum(skb, hdr, tot_len); |
150 | ||
151 | return 0; | |
152 | } | |
b04c80d3 | 153 | EXPORT_SYMBOL_GPL(seg6_do_srh_encap); |
6c8702c6 DL |
154 | |
155 | /* insert an SRH within an IPv6 packet, just after the IPv6 header */ | |
b04c80d3 | 156 | int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) |
6c8702c6 DL |
157 | { |
158 | struct ipv6hdr *hdr, *oldhdr; | |
159 | struct ipv6_sr_hdr *isrh; | |
160 | int hdrlen, err; | |
161 | ||
162 | hdrlen = (osrh->hdrlen + 1) << 3; | |
163 | ||
19d5a26f | 164 | err = skb_cow_head(skb, hdrlen); |
6c8702c6 DL |
165 | if (unlikely(err)) |
166 | return err; | |
167 | ||
168 | oldhdr = ipv6_hdr(skb); | |
169 | ||
170 | skb_pull(skb, sizeof(struct ipv6hdr)); | |
171 | skb_postpull_rcsum(skb, skb_network_header(skb), | |
172 | sizeof(struct ipv6hdr)); | |
173 | ||
174 | skb_push(skb, sizeof(struct ipv6hdr) + hdrlen); | |
175 | skb_reset_network_header(skb); | |
176 | skb_mac_header_rebuild(skb); | |
177 | ||
178 | hdr = ipv6_hdr(skb); | |
179 | ||
180 | memmove(hdr, oldhdr, sizeof(*hdr)); | |
181 | ||
182 | isrh = (void *)hdr + sizeof(*hdr); | |
183 | memcpy(isrh, osrh, hdrlen); | |
184 | ||
185 | isrh->nexthdr = hdr->nexthdr; | |
186 | hdr->nexthdr = NEXTHDR_ROUTING; | |
187 | ||
188 | isrh->segments[0] = hdr->daddr; | |
189 | hdr->daddr = isrh->segments[isrh->first_segment]; | |
190 | ||
9baee834 DL |
191 | #ifdef CONFIG_IPV6_SEG6_HMAC |
192 | if (sr_has_hmac(isrh)) { | |
193 | struct net *net = dev_net(skb_dst(skb)->dev); | |
194 | ||
195 | err = seg6_push_hmac(net, &hdr->saddr, isrh); | |
196 | if (unlikely(err)) | |
197 | return err; | |
198 | } | |
199 | #endif | |
200 | ||
6c8702c6 DL |
201 | skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen); |
202 | ||
203 | return 0; | |
204 | } | |
b04c80d3 | 205 | EXPORT_SYMBOL_GPL(seg6_do_srh_inline); |
6c8702c6 DL |
206 | |
207 | static int seg6_do_srh(struct sk_buff *skb) | |
208 | { | |
209 | struct dst_entry *dst = skb_dst(skb); | |
210 | struct seg6_iptunnel_encap *tinfo; | |
32d99d0b | 211 | int proto, err = 0; |
6c8702c6 DL |
212 | |
213 | tinfo = seg6_encap_lwtunnel(dst->lwtstate); | |
214 | ||
6c8702c6 | 215 | switch (tinfo->mode) { |
6c8702c6 | 216 | case SEG6_IPTUN_MODE_INLINE: |
32d99d0b DL |
217 | if (skb->protocol != htons(ETH_P_IPV6)) |
218 | return -EINVAL; | |
219 | ||
6c8702c6 | 220 | err = seg6_do_srh_inline(skb, tinfo->srh); |
32d99d0b DL |
221 | if (err) |
222 | return err; | |
6c8702c6 | 223 | break; |
6c8702c6 | 224 | case SEG6_IPTUN_MODE_ENCAP: |
5807b22c DL |
225 | err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6); |
226 | if (err) | |
227 | return err; | |
228 | ||
32d99d0b DL |
229 | if (skb->protocol == htons(ETH_P_IPV6)) |
230 | proto = IPPROTO_IPV6; | |
231 | else if (skb->protocol == htons(ETH_P_IP)) | |
232 | proto = IPPROTO_IPIP; | |
233 | else | |
234 | return -EINVAL; | |
235 | ||
236 | err = seg6_do_srh_encap(skb, tinfo->srh, proto); | |
237 | if (err) | |
238 | return err; | |
239 | ||
5807b22c DL |
240 | skb_set_inner_transport_header(skb, skb_transport_offset(skb)); |
241 | skb_set_inner_protocol(skb, skb->protocol); | |
38ee7f2d DL |
242 | skb->protocol = htons(ETH_P_IPV6); |
243 | break; | |
244 | case SEG6_IPTUN_MODE_L2ENCAP: | |
245 | if (!skb_mac_header_was_set(skb)) | |
246 | return -EINVAL; | |
247 | ||
248 | if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0) | |
249 | return -ENOMEM; | |
250 | ||
251 | skb_mac_header_rebuild(skb); | |
252 | skb_push(skb, skb->mac_len); | |
253 | ||
254 | err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE); | |
255 | if (err) | |
256 | return err; | |
257 | ||
32d99d0b | 258 | skb->protocol = htons(ETH_P_IPV6); |
6c8702c6 DL |
259 | break; |
260 | } | |
261 | ||
6c8702c6 DL |
262 | ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); |
263 | skb_set_transport_header(skb, sizeof(struct ipv6hdr)); | |
264 | ||
6c8702c6 DL |
265 | return 0; |
266 | } | |
267 | ||
bb4005ba | 268 | static int seg6_input(struct sk_buff *skb) |
6c8702c6 | 269 | { |
af4a2209 DL |
270 | struct dst_entry *orig_dst = skb_dst(skb); |
271 | struct dst_entry *dst = NULL; | |
272 | struct seg6_lwt *slwt; | |
6c8702c6 DL |
273 | int err; |
274 | ||
275 | err = seg6_do_srh(skb); | |
276 | if (unlikely(err)) { | |
277 | kfree_skb(skb); | |
278 | return err; | |
279 | } | |
280 | ||
af4a2209 DL |
281 | slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); |
282 | ||
af4a2209 DL |
283 | preempt_disable(); |
284 | dst = dst_cache_get(&slwt->cache); | |
285 | preempt_enable(); | |
af4a2209 | 286 | |
6c8702c6 | 287 | skb_dst_drop(skb); |
af4a2209 DL |
288 | |
289 | if (!dst) { | |
290 | ip6_route_input(skb); | |
af4a2209 DL |
291 | dst = skb_dst(skb); |
292 | if (!dst->error) { | |
293 | preempt_disable(); | |
294 | dst_cache_set_ip6(&slwt->cache, dst, | |
295 | &ipv6_hdr(skb)->saddr); | |
296 | preempt_enable(); | |
297 | } | |
af4a2209 DL |
298 | } else { |
299 | skb_dst_set(skb, dst); | |
300 | } | |
6c8702c6 | 301 | |
af3b5158 DL |
302 | err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); |
303 | if (unlikely(err)) | |
304 | return err; | |
305 | ||
6c8702c6 DL |
306 | return dst_input(skb); |
307 | } | |
308 | ||
bb4005ba | 309 | static int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
6c8702c6 DL |
310 | { |
311 | struct dst_entry *orig_dst = skb_dst(skb); | |
312 | struct dst_entry *dst = NULL; | |
313 | struct seg6_lwt *slwt; | |
314 | int err = -EINVAL; | |
315 | ||
316 | err = seg6_do_srh(skb); | |
317 | if (unlikely(err)) | |
318 | goto drop; | |
319 | ||
320 | slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); | |
321 | ||
fa79581e | 322 | preempt_disable(); |
6c8702c6 | 323 | dst = dst_cache_get(&slwt->cache); |
fa79581e | 324 | preempt_enable(); |
6c8702c6 DL |
325 | |
326 | if (unlikely(!dst)) { | |
327 | struct ipv6hdr *hdr = ipv6_hdr(skb); | |
328 | struct flowi6 fl6; | |
329 | ||
330 | fl6.daddr = hdr->daddr; | |
331 | fl6.saddr = hdr->saddr; | |
332 | fl6.flowlabel = ip6_flowinfo(hdr); | |
333 | fl6.flowi6_mark = skb->mark; | |
334 | fl6.flowi6_proto = hdr->nexthdr; | |
335 | ||
336 | dst = ip6_route_output(net, NULL, &fl6); | |
337 | if (dst->error) { | |
338 | err = dst->error; | |
339 | dst_release(dst); | |
340 | goto drop; | |
341 | } | |
342 | ||
fa79581e | 343 | preempt_disable(); |
6c8702c6 | 344 | dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr); |
fa79581e | 345 | preempt_enable(); |
6c8702c6 DL |
346 | } |
347 | ||
348 | skb_dst_drop(skb); | |
349 | skb_dst_set(skb, dst); | |
350 | ||
af3b5158 DL |
351 | err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); |
352 | if (unlikely(err)) | |
353 | goto drop; | |
354 | ||
6c8702c6 DL |
355 | return dst_output(net, sk, skb); |
356 | drop: | |
357 | kfree_skb(skb); | |
358 | return err; | |
359 | } | |
360 | ||
30357d7d | 361 | static int seg6_build_state(struct nlattr *nla, |
6c8702c6 | 362 | unsigned int family, const void *cfg, |
9ae28727 DA |
363 | struct lwtunnel_state **ts, |
364 | struct netlink_ext_ack *extack) | |
6c8702c6 DL |
365 | { |
366 | struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1]; | |
367 | struct seg6_iptunnel_encap *tuninfo; | |
368 | struct lwtunnel_state *newts; | |
369 | int tuninfo_len, min_size; | |
370 | struct seg6_lwt *slwt; | |
371 | int err; | |
372 | ||
32d99d0b DL |
373 | if (family != AF_INET && family != AF_INET6) |
374 | return -EINVAL; | |
375 | ||
6c8702c6 | 376 | err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla, |
9ae28727 | 377 | seg6_iptunnel_policy, extack); |
6c8702c6 DL |
378 | |
379 | if (err < 0) | |
380 | return err; | |
381 | ||
382 | if (!tb[SEG6_IPTUNNEL_SRH]) | |
383 | return -EINVAL; | |
384 | ||
385 | tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]); | |
386 | tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]); | |
387 | ||
388 | /* tuninfo must contain at least the iptunnel encap structure, | |
389 | * the SRH and one segment | |
390 | */ | |
391 | min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) + | |
392 | sizeof(struct in6_addr); | |
393 | if (tuninfo_len < min_size) | |
394 | return -EINVAL; | |
395 | ||
396 | switch (tuninfo->mode) { | |
6c8702c6 | 397 | case SEG6_IPTUN_MODE_INLINE: |
32d99d0b DL |
398 | if (family != AF_INET6) |
399 | return -EINVAL; | |
400 | ||
6c8702c6 | 401 | break; |
6c8702c6 DL |
402 | case SEG6_IPTUN_MODE_ENCAP: |
403 | break; | |
38ee7f2d DL |
404 | case SEG6_IPTUN_MODE_L2ENCAP: |
405 | break; | |
6c8702c6 DL |
406 | default: |
407 | return -EINVAL; | |
408 | } | |
409 | ||
410 | /* verify that SRH is consistent */ | |
411 | if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo))) | |
412 | return -EINVAL; | |
413 | ||
414 | newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt)); | |
415 | if (!newts) | |
416 | return -ENOMEM; | |
417 | ||
418 | slwt = seg6_lwt_lwtunnel(newts); | |
419 | ||
191f86ca | 420 | err = dst_cache_init(&slwt->cache, GFP_ATOMIC); |
6c8702c6 DL |
421 | if (err) { |
422 | kfree(newts); | |
423 | return err; | |
424 | } | |
6c8702c6 DL |
425 | |
426 | memcpy(&slwt->tuninfo, tuninfo, tuninfo_len); | |
427 | ||
428 | newts->type = LWTUNNEL_ENCAP_SEG6; | |
38ee7f2d DL |
429 | newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT; |
430 | ||
431 | if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP) | |
432 | newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; | |
433 | ||
6c8702c6 DL |
434 | newts->headroom = seg6_lwt_headroom(tuninfo); |
435 | ||
436 | *ts = newts; | |
437 | ||
438 | return 0; | |
439 | } | |
440 | ||
6c8702c6 DL |
441 | static void seg6_destroy_state(struct lwtunnel_state *lwt) |
442 | { | |
443 | dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache); | |
444 | } | |
6c8702c6 DL |
445 | |
446 | static int seg6_fill_encap_info(struct sk_buff *skb, | |
447 | struct lwtunnel_state *lwtstate) | |
448 | { | |
449 | struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate); | |
450 | ||
451 | if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo)) | |
452 | return -EMSGSIZE; | |
453 | ||
454 | return 0; | |
455 | } | |
456 | ||
457 | static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate) | |
458 | { | |
459 | struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate); | |
460 | ||
461 | return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo)); | |
462 | } | |
463 | ||
464 | static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) | |
465 | { | |
466 | struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a); | |
467 | struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b); | |
468 | int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr); | |
469 | ||
470 | if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr)) | |
471 | return 1; | |
472 | ||
473 | return memcmp(a_hdr, b_hdr, len); | |
474 | } | |
475 | ||
476 | static const struct lwtunnel_encap_ops seg6_iptun_ops = { | |
477 | .build_state = seg6_build_state, | |
6c8702c6 | 478 | .destroy_state = seg6_destroy_state, |
6c8702c6 DL |
479 | .output = seg6_output, |
480 | .input = seg6_input, | |
481 | .fill_encap = seg6_fill_encap_info, | |
482 | .get_encap_size = seg6_encap_nlsize, | |
483 | .cmp_encap = seg6_encap_cmp, | |
88ff7334 | 484 | .owner = THIS_MODULE, |
6c8702c6 DL |
485 | }; |
486 | ||
487 | int __init seg6_iptunnel_init(void) | |
488 | { | |
489 | return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6); | |
490 | } | |
491 | ||
492 | void seg6_iptunnel_exit(void) | |
493 | { | |
494 | lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6); | |
495 | } |