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