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
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
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 */
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
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 (hinfo) {
195 err = seg6_hmac_info_del(net, hmackeyid);
196 if (err)
197 goto out_unlock;
198 }
199
200 secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
201
202 hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
203 if (!hinfo) {
204 err = -ENOMEM;
205 goto out_unlock;
206 }
207
208 memcpy(hinfo->secret, secret, slen);
209 hinfo->slen = slen;
210 hinfo->alg_id = algid;
211 hinfo->hmackeyid = hmackeyid;
212
213 err = seg6_hmac_info_add(net, hmackeyid, hinfo);
214 if (err)
215 kfree(hinfo);
216
217 out_unlock:
218 mutex_unlock(&sdata->lock);
219 return err;
220 }
221
222 #else
223
224 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
225 {
226 return -ENOTSUPP;
227 }
228
229 #endif
230
231 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
232 {
233 struct net *net = genl_info_net(info);
234 struct in6_addr *val, *t_old, *t_new;
235 struct seg6_pernet_data *sdata;
236
237 sdata = seg6_pernet(net);
238
239 if (!info->attrs[SEG6_ATTR_DST])
240 return -EINVAL;
241
242 val = nla_data(info->attrs[SEG6_ATTR_DST]);
243 t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
244 if (!t_new)
245 return -ENOMEM;
246
247 mutex_lock(&sdata->lock);
248
249 t_old = sdata->tun_src;
250 rcu_assign_pointer(sdata->tun_src, t_new);
251
252 mutex_unlock(&sdata->lock);
253
254 synchronize_net();
255 kfree(t_old);
256
257 return 0;
258 }
259
260 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
261 {
262 struct net *net = genl_info_net(info);
263 struct in6_addr *tun_src;
264 struct sk_buff *msg;
265 void *hdr;
266
267 msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
268 if (!msg)
269 return -ENOMEM;
270
271 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
272 &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
273 if (!hdr)
274 goto free_msg;
275
276 rcu_read_lock();
277 tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
278
279 if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
280 goto nla_put_failure;
281
282 rcu_read_unlock();
283
284 genlmsg_end(msg, hdr);
285 return genlmsg_reply(msg, info);
286
287 nla_put_failure:
288 rcu_read_unlock();
289 free_msg:
290 nlmsg_free(msg);
291 return -ENOMEM;
292 }
293
294 #ifdef CONFIG_IPV6_SEG6_HMAC
295
296 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
297 struct sk_buff *msg)
298 {
299 if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
300 nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
301 nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
302 nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
303 return -1;
304
305 return 0;
306 }
307
308 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
309 u32 portid, u32 seq, u32 flags,
310 struct sk_buff *skb, u8 cmd)
311 {
312 void *hdr;
313
314 hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
315 if (!hdr)
316 return -ENOMEM;
317
318 if (__seg6_hmac_fill_info(hinfo, skb) < 0)
319 goto nla_put_failure;
320
321 genlmsg_end(skb, hdr);
322 return 0;
323
324 nla_put_failure:
325 genlmsg_cancel(skb, hdr);
326 return -EMSGSIZE;
327 }
328
329 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
330 {
331 struct net *net = sock_net(cb->skb->sk);
332 struct seg6_pernet_data *sdata;
333 struct rhashtable_iter *iter;
334
335 sdata = seg6_pernet(net);
336 iter = (struct rhashtable_iter *)cb->args[0];
337
338 if (!iter) {
339 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
340 if (!iter)
341 return -ENOMEM;
342
343 cb->args[0] = (long)iter;
344 }
345
346 rhashtable_walk_enter(&sdata->hmac_infos, iter);
347
348 return 0;
349 }
350
351 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
352 {
353 struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
354
355 rhashtable_walk_exit(iter);
356
357 kfree(iter);
358
359 return 0;
360 }
361
362 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
363 {
364 struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
365 struct seg6_hmac_info *hinfo;
366 int ret;
367
368 rhashtable_walk_start(iter);
369
370 for (;;) {
371 hinfo = rhashtable_walk_next(iter);
372
373 if (IS_ERR(hinfo)) {
374 if (PTR_ERR(hinfo) == -EAGAIN)
375 continue;
376 ret = PTR_ERR(hinfo);
377 goto done;
378 } else if (!hinfo) {
379 break;
380 }
381
382 ret = __seg6_genl_dumphmac_element(hinfo,
383 NETLINK_CB(cb->skb).portid,
384 cb->nlh->nlmsg_seq,
385 NLM_F_MULTI,
386 skb, SEG6_CMD_DUMPHMAC);
387 if (ret)
388 goto done;
389 }
390
391 ret = skb->len;
392
393 done:
394 rhashtable_walk_stop(iter);
395 return ret;
396 }
397
398 #else
399
400 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
401 {
402 return 0;
403 }
404
405 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
406 {
407 return 0;
408 }
409
410 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
411 {
412 return -ENOTSUPP;
413 }
414
415 #endif
416
417 static int __net_init seg6_net_init(struct net *net)
418 {
419 struct seg6_pernet_data *sdata;
420
421 sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
422 if (!sdata)
423 return -ENOMEM;
424
425 mutex_init(&sdata->lock);
426
427 sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
428 if (!sdata->tun_src) {
429 kfree(sdata);
430 return -ENOMEM;
431 }
432
433 net->ipv6.seg6_data = sdata;
434
435 #ifdef CONFIG_IPV6_SEG6_HMAC
436 if (seg6_hmac_net_init(net)) {
437 kfree(rcu_dereference_raw(sdata->tun_src));
438 kfree(sdata);
439 return -ENOMEM;
440 }
441 #endif
442
443 return 0;
444 }
445
446 static void __net_exit seg6_net_exit(struct net *net)
447 {
448 struct seg6_pernet_data *sdata = seg6_pernet(net);
449
450 #ifdef CONFIG_IPV6_SEG6_HMAC
451 seg6_hmac_net_exit(net);
452 #endif
453
454 kfree(rcu_dereference_raw(sdata->tun_src));
455 kfree(sdata);
456 }
457
458 static struct pernet_operations ip6_segments_ops = {
459 .init = seg6_net_init,
460 .exit = seg6_net_exit,
461 };
462
463 static const struct genl_ops seg6_genl_ops[] = {
464 {
465 .cmd = SEG6_CMD_SETHMAC,
466 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
467 .doit = seg6_genl_sethmac,
468 .flags = GENL_ADMIN_PERM,
469 },
470 {
471 .cmd = SEG6_CMD_DUMPHMAC,
472 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
473 .start = seg6_genl_dumphmac_start,
474 .dumpit = seg6_genl_dumphmac,
475 .done = seg6_genl_dumphmac_done,
476 .flags = GENL_ADMIN_PERM,
477 },
478 {
479 .cmd = SEG6_CMD_SET_TUNSRC,
480 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
481 .doit = seg6_genl_set_tunsrc,
482 .flags = GENL_ADMIN_PERM,
483 },
484 {
485 .cmd = SEG6_CMD_GET_TUNSRC,
486 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
487 .doit = seg6_genl_get_tunsrc,
488 .flags = GENL_ADMIN_PERM,
489 },
490 };
491
492 static struct genl_family seg6_genl_family __ro_after_init = {
493 .hdrsize = 0,
494 .name = SEG6_GENL_NAME,
495 .version = SEG6_GENL_VERSION,
496 .maxattr = SEG6_ATTR_MAX,
497 .policy = seg6_genl_policy,
498 .netnsok = true,
499 .parallel_ops = true,
500 .ops = seg6_genl_ops,
501 .n_ops = ARRAY_SIZE(seg6_genl_ops),
502 .module = THIS_MODULE,
503 };
504
505 int __init seg6_init(void)
506 {
507 int err;
508
509 err = genl_register_family(&seg6_genl_family);
510 if (err)
511 goto out;
512
513 err = register_pernet_subsys(&ip6_segments_ops);
514 if (err)
515 goto out_unregister_genl;
516
517 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
518 err = seg6_iptunnel_init();
519 if (err)
520 goto out_unregister_pernet;
521
522 err = seg6_local_init();
523 if (err)
524 goto out_unregister_pernet;
525 #endif
526
527 #ifdef CONFIG_IPV6_SEG6_HMAC
528 err = seg6_hmac_init();
529 if (err)
530 goto out_unregister_iptun;
531 #endif
532
533 pr_info("Segment Routing with IPv6\n");
534
535 out:
536 return err;
537 #ifdef CONFIG_IPV6_SEG6_HMAC
538 out_unregister_iptun:
539 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
540 seg6_local_exit();
541 seg6_iptunnel_exit();
542 #endif
543 #endif
544 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
545 out_unregister_pernet:
546 unregister_pernet_subsys(&ip6_segments_ops);
547 #endif
548 out_unregister_genl:
549 genl_unregister_family(&seg6_genl_family);
550 goto out;
551 }
552
553 void seg6_exit(void)
554 {
555 #ifdef CONFIG_IPV6_SEG6_HMAC
556 seg6_hmac_exit();
557 #endif
558 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
559 seg6_iptunnel_exit();
560 #endif
561 unregister_pernet_subsys(&ip6_segments_ops);
562 genl_unregister_family(&seg6_genl_family);
563 }
564
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