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/errno.h>
10 #include <linux/types.h>
11 #include <linux/socket.h>
12 #include <linux/net.h>
13 #include <linux/in6.h>
14 #include <linux/slab.h>
15 #include <linux/rhashtable.h>
16
17 #include <net/ipv6.h>
18 #include <net/protocol.h>
19
20 #include <net/seg6.h>
21 #include <net/genetlink.h>
22 #include <linux/seg6.h>
23 #include <linux/seg6_genl.h>
24 #ifdef CONFIG_IPV6_SEG6_HMAC
25 #include <net/seg6_hmac.h>
26 #endif
27
seg6_validate_srh(struct ipv6_sr_hdr * srh,int len,bool reduced)28 bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len, bool reduced)
29 {
30 unsigned int tlv_offset;
31 int max_last_entry;
32 int trailing;
33
34 if (srh->type != IPV6_SRCRT_TYPE_4)
35 return false;
36
37 if (((srh->hdrlen + 1) << 3) != len)
38 return false;
39
40 if (!reduced && srh->segments_left > srh->first_segment) {
41 return false;
42 } else {
43 max_last_entry = (srh->hdrlen / 2) - 1;
44
45 if (srh->first_segment > max_last_entry)
46 return false;
47
48 if (srh->segments_left > srh->first_segment + 1)
49 return false;
50 }
51
52 tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
53
54 trailing = len - tlv_offset;
55 if (trailing < 0)
56 return false;
57
58 while (trailing) {
59 struct sr6_tlv *tlv;
60 unsigned int tlv_len;
61
62 if (trailing < sizeof(*tlv))
63 return false;
64
65 tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
66 tlv_len = sizeof(*tlv) + tlv->len;
67
68 trailing -= tlv_len;
69 if (trailing < 0)
70 return false;
71
72 tlv_offset += tlv_len;
73 }
74
75 return true;
76 }
77
seg6_get_srh(struct sk_buff * skb,int flags)78 struct ipv6_sr_hdr *seg6_get_srh(struct sk_buff *skb, int flags)
79 {
80 struct ipv6_sr_hdr *srh;
81 int len, srhoff = 0;
82
83 if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0)
84 return NULL;
85
86 if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
87 return NULL;
88
89 srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
90
91 len = (srh->hdrlen + 1) << 3;
92
93 if (!pskb_may_pull(skb, srhoff + len))
94 return NULL;
95
96 /* note that pskb_may_pull may change pointers in header;
97 * for this reason it is necessary to reload them when needed.
98 */
99 srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
100
101 if (!seg6_validate_srh(srh, len, true))
102 return NULL;
103
104 return srh;
105 }
106
107 /* Determine if an ICMP invoking packet contains a segment routing
108 * header. If it does, extract the offset to the true destination
109 * address, which is in the first segment address.
110 */
seg6_icmp_srh(struct sk_buff * skb,struct inet6_skb_parm * opt)111 void seg6_icmp_srh(struct sk_buff *skb, struct inet6_skb_parm *opt)
112 {
113 __u16 network_header = skb->network_header;
114 struct ipv6_sr_hdr *srh;
115
116 /* Update network header to point to the invoking packet
117 * inside the ICMP packet, so we can use the seg6_get_srh()
118 * helper.
119 */
120 skb_reset_network_header(skb);
121
122 srh = seg6_get_srh(skb, 0);
123 if (!srh)
124 goto out;
125
126 if (srh->type != IPV6_SRCRT_TYPE_4)
127 goto out;
128
129 opt->flags |= IP6SKB_SEG6;
130 opt->srhoff = (unsigned char *)srh - skb->data;
131
132 out:
133 /* Restore the network header back to the ICMP packet */
134 skb->network_header = network_header;
135 }
136
137 static struct genl_family seg6_genl_family;
138
139 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
140 [SEG6_ATTR_DST] = { .type = NLA_BINARY,
141 .len = sizeof(struct in6_addr) },
142 [SEG6_ATTR_DSTLEN] = { .type = NLA_S32, },
143 [SEG6_ATTR_HMACKEYID] = { .type = NLA_U32, },
144 [SEG6_ATTR_SECRET] = { .type = NLA_BINARY, },
145 [SEG6_ATTR_SECRETLEN] = { .type = NLA_U8, },
146 [SEG6_ATTR_ALGID] = { .type = NLA_U8, },
147 [SEG6_ATTR_HMACINFO] = { .type = NLA_NESTED, },
148 };
149
150 #ifdef CONFIG_IPV6_SEG6_HMAC
151
seg6_genl_sethmac(struct sk_buff * skb,struct genl_info * info)152 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
153 {
154 struct net *net = genl_info_net(info);
155 struct seg6_pernet_data *sdata;
156 struct seg6_hmac_info *hinfo;
157 u32 hmackeyid;
158 char *secret;
159 int err = 0;
160 u8 algid;
161 u8 slen;
162
163 sdata = seg6_pernet(net);
164
165 if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
166 !info->attrs[SEG6_ATTR_SECRETLEN] ||
167 !info->attrs[SEG6_ATTR_ALGID])
168 return -EINVAL;
169
170 hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
171 slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
172 algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
173
174 if (hmackeyid == 0)
175 return -EINVAL;
176
177 if (slen > SEG6_HMAC_SECRET_LEN)
178 return -EINVAL;
179
180 mutex_lock(&sdata->lock);
181 hinfo = seg6_hmac_info_lookup(net, hmackeyid);
182
183 if (!slen) {
184 err = seg6_hmac_info_del(net, hmackeyid);
185
186 goto out_unlock;
187 }
188
189 if (!info->attrs[SEG6_ATTR_SECRET]) {
190 err = -EINVAL;
191 goto out_unlock;
192 }
193
194 if (slen > nla_len(info->attrs[SEG6_ATTR_SECRET])) {
195 err = -EINVAL;
196 goto out_unlock;
197 }
198
199 if (hinfo) {
200 err = seg6_hmac_info_del(net, hmackeyid);
201 if (err)
202 goto out_unlock;
203 }
204
205 secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
206
207 hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
208 if (!hinfo) {
209 err = -ENOMEM;
210 goto out_unlock;
211 }
212
213 memcpy(hinfo->secret, secret, slen);
214 hinfo->slen = slen;
215 hinfo->alg_id = algid;
216 hinfo->hmackeyid = hmackeyid;
217
218 err = seg6_hmac_info_add(net, hmackeyid, hinfo);
219 if (err)
220 kfree(hinfo);
221
222 out_unlock:
223 mutex_unlock(&sdata->lock);
224 return err;
225 }
226
227 #else
228
seg6_genl_sethmac(struct sk_buff * skb,struct genl_info * info)229 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
230 {
231 return -ENOTSUPP;
232 }
233
234 #endif
235
seg6_genl_set_tunsrc(struct sk_buff * skb,struct genl_info * info)236 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
237 {
238 struct net *net = genl_info_net(info);
239 struct in6_addr *val, *t_old, *t_new;
240 struct seg6_pernet_data *sdata;
241
242 sdata = seg6_pernet(net);
243
244 if (!info->attrs[SEG6_ATTR_DST])
245 return -EINVAL;
246
247 val = nla_data(info->attrs[SEG6_ATTR_DST]);
248 t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
249 if (!t_new)
250 return -ENOMEM;
251
252 mutex_lock(&sdata->lock);
253
254 t_old = sdata->tun_src;
255 rcu_assign_pointer(sdata->tun_src, t_new);
256
257 mutex_unlock(&sdata->lock);
258
259 synchronize_net();
260 kfree(t_old);
261
262 return 0;
263 }
264
seg6_genl_get_tunsrc(struct sk_buff * skb,struct genl_info * info)265 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
266 {
267 struct net *net = genl_info_net(info);
268 struct in6_addr *tun_src;
269 struct sk_buff *msg;
270 void *hdr;
271
272 msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
273 if (!msg)
274 return -ENOMEM;
275
276 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
277 &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
278 if (!hdr)
279 goto free_msg;
280
281 rcu_read_lock();
282 tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
283
284 if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
285 goto nla_put_failure;
286
287 rcu_read_unlock();
288
289 genlmsg_end(msg, hdr);
290 return genlmsg_reply(msg, info);
291
292 nla_put_failure:
293 rcu_read_unlock();
294 free_msg:
295 nlmsg_free(msg);
296 return -ENOMEM;
297 }
298
299 #ifdef CONFIG_IPV6_SEG6_HMAC
300
__seg6_hmac_fill_info(struct seg6_hmac_info * hinfo,struct sk_buff * msg)301 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
302 struct sk_buff *msg)
303 {
304 if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
305 nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
306 nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
307 nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
308 return -1;
309
310 return 0;
311 }
312
__seg6_genl_dumphmac_element(struct seg6_hmac_info * hinfo,u32 portid,u32 seq,u32 flags,struct sk_buff * skb,u8 cmd)313 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
314 u32 portid, u32 seq, u32 flags,
315 struct sk_buff *skb, u8 cmd)
316 {
317 void *hdr;
318
319 hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
320 if (!hdr)
321 return -ENOMEM;
322
323 if (__seg6_hmac_fill_info(hinfo, skb) < 0)
324 goto nla_put_failure;
325
326 genlmsg_end(skb, hdr);
327 return 0;
328
329 nla_put_failure:
330 genlmsg_cancel(skb, hdr);
331 return -EMSGSIZE;
332 }
333
seg6_genl_dumphmac_start(struct netlink_callback * cb)334 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
335 {
336 struct net *net = sock_net(cb->skb->sk);
337 struct seg6_pernet_data *sdata;
338 struct rhashtable_iter *iter;
339
340 sdata = seg6_pernet(net);
341 iter = (struct rhashtable_iter *)cb->args[0];
342
343 if (!iter) {
344 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
345 if (!iter)
346 return -ENOMEM;
347
348 cb->args[0] = (long)iter;
349 }
350
351 rhashtable_walk_enter(&sdata->hmac_infos, iter);
352
353 return 0;
354 }
355
seg6_genl_dumphmac_done(struct netlink_callback * cb)356 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
357 {
358 struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
359
360 rhashtable_walk_exit(iter);
361
362 kfree(iter);
363
364 return 0;
365 }
366
seg6_genl_dumphmac(struct sk_buff * skb,struct netlink_callback * cb)367 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
368 {
369 struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
370 struct seg6_hmac_info *hinfo;
371 int ret;
372
373 rhashtable_walk_start(iter);
374
375 for (;;) {
376 hinfo = rhashtable_walk_next(iter);
377
378 if (IS_ERR(hinfo)) {
379 if (PTR_ERR(hinfo) == -EAGAIN)
380 continue;
381 ret = PTR_ERR(hinfo);
382 goto done;
383 } else if (!hinfo) {
384 break;
385 }
386
387 ret = __seg6_genl_dumphmac_element(hinfo,
388 NETLINK_CB(cb->skb).portid,
389 cb->nlh->nlmsg_seq,
390 NLM_F_MULTI,
391 skb, SEG6_CMD_DUMPHMAC);
392 if (ret)
393 goto done;
394 }
395
396 ret = skb->len;
397
398 done:
399 rhashtable_walk_stop(iter);
400 return ret;
401 }
402
403 #else
404
seg6_genl_dumphmac_start(struct netlink_callback * cb)405 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
406 {
407 return 0;
408 }
409
seg6_genl_dumphmac_done(struct netlink_callback * cb)410 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
411 {
412 return 0;
413 }
414
seg6_genl_dumphmac(struct sk_buff * skb,struct netlink_callback * cb)415 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
416 {
417 return -ENOTSUPP;
418 }
419
420 #endif
421
seg6_net_init(struct net * net)422 static int __net_init seg6_net_init(struct net *net)
423 {
424 struct seg6_pernet_data *sdata;
425
426 sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
427 if (!sdata)
428 return -ENOMEM;
429
430 mutex_init(&sdata->lock);
431
432 sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
433 if (!sdata->tun_src) {
434 kfree(sdata);
435 return -ENOMEM;
436 }
437
438 net->ipv6.seg6_data = sdata;
439
440 #ifdef CONFIG_IPV6_SEG6_HMAC
441 if (seg6_hmac_net_init(net)) {
442 kfree(rcu_dereference_raw(sdata->tun_src));
443 kfree(sdata);
444 return -ENOMEM;
445 }
446 #endif
447
448 return 0;
449 }
450
seg6_net_exit(struct net * net)451 static void __net_exit seg6_net_exit(struct net *net)
452 {
453 struct seg6_pernet_data *sdata = seg6_pernet(net);
454
455 #ifdef CONFIG_IPV6_SEG6_HMAC
456 seg6_hmac_net_exit(net);
457 #endif
458
459 kfree(rcu_dereference_raw(sdata->tun_src));
460 kfree(sdata);
461 }
462
463 static struct pernet_operations ip6_segments_ops = {
464 .init = seg6_net_init,
465 .exit = seg6_net_exit,
466 };
467
468 static const struct genl_ops seg6_genl_ops[] = {
469 {
470 .cmd = SEG6_CMD_SETHMAC,
471 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
472 .doit = seg6_genl_sethmac,
473 .flags = GENL_ADMIN_PERM,
474 },
475 {
476 .cmd = SEG6_CMD_DUMPHMAC,
477 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
478 .start = seg6_genl_dumphmac_start,
479 .dumpit = seg6_genl_dumphmac,
480 .done = seg6_genl_dumphmac_done,
481 .flags = GENL_ADMIN_PERM,
482 },
483 {
484 .cmd = SEG6_CMD_SET_TUNSRC,
485 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
486 .doit = seg6_genl_set_tunsrc,
487 .flags = GENL_ADMIN_PERM,
488 },
489 {
490 .cmd = SEG6_CMD_GET_TUNSRC,
491 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
492 .doit = seg6_genl_get_tunsrc,
493 .flags = GENL_ADMIN_PERM,
494 },
495 };
496
497 static struct genl_family seg6_genl_family __ro_after_init = {
498 .hdrsize = 0,
499 .name = SEG6_GENL_NAME,
500 .version = SEG6_GENL_VERSION,
501 .maxattr = SEG6_ATTR_MAX,
502 .policy = seg6_genl_policy,
503 .netnsok = true,
504 .parallel_ops = true,
505 .ops = seg6_genl_ops,
506 .n_ops = ARRAY_SIZE(seg6_genl_ops),
507 .resv_start_op = SEG6_CMD_GET_TUNSRC + 1,
508 .module = THIS_MODULE,
509 };
510
seg6_init(void)511 int __init seg6_init(void)
512 {
513 int err;
514
515 err = register_pernet_subsys(&ip6_segments_ops);
516 if (err)
517 goto out;
518
519 err = genl_register_family(&seg6_genl_family);
520 if (err)
521 goto out_unregister_pernet;
522
523 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
524 err = seg6_iptunnel_init();
525 if (err)
526 goto out_unregister_genl;
527
528 err = seg6_local_init();
529 if (err) {
530 seg6_iptunnel_exit();
531 goto out_unregister_genl;
532 }
533 #endif
534
535 #ifdef CONFIG_IPV6_SEG6_HMAC
536 err = seg6_hmac_init();
537 if (err)
538 goto out_unregister_iptun;
539 #endif
540
541 pr_info("Segment Routing with IPv6\n");
542
543 out:
544 return err;
545 #ifdef CONFIG_IPV6_SEG6_HMAC
546 out_unregister_iptun:
547 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
548 seg6_local_exit();
549 seg6_iptunnel_exit();
550 #endif
551 #endif
552 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
553 out_unregister_genl:
554 #endif
555 #if IS_ENABLED(CONFIG_IPV6_SEG6_LWTUNNEL) || IS_ENABLED(CONFIG_IPV6_SEG6_HMAC)
556 genl_unregister_family(&seg6_genl_family);
557 #endif
558 out_unregister_pernet:
559 unregister_pernet_subsys(&ip6_segments_ops);
560 goto out;
561 }
562
seg6_exit(void)563 void seg6_exit(void)
564 {
565 #ifdef CONFIG_IPV6_SEG6_HMAC
566 seg6_hmac_exit();
567 #endif
568 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
569 seg6_local_exit();
570 seg6_iptunnel_exit();
571 #endif
572 genl_unregister_family(&seg6_genl_family);
573 unregister_pernet_subsys(&ip6_segments_ops);
574 }
575