net/ipv6/seg6.c

   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 static struct genl_family seg6_genl_family;
  79
  80 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
  81         [SEG6_ATTR_DST]                         = { .type = NLA_BINARY,
  82                 .len = sizeof(struct in6_addr) },
  83         [SEG6_ATTR_DSTLEN]                      = { .type = NLA_S32, },
  84         [SEG6_ATTR_HMACKEYID]           = { .type = NLA_U32, },
  85         [SEG6_ATTR_SECRET]                      = { .type = NLA_BINARY, },
  86         [SEG6_ATTR_SECRETLEN]           = { .type = NLA_U8, },
  87         [SEG6_ATTR_ALGID]                       = { .type = NLA_U8, },
  88         [SEG6_ATTR_HMACINFO]            = { .type = NLA_NESTED, },
  89 };
  90
  91 #ifdef CONFIG_IPV6_SEG6_HMAC
  92
  93 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
  94 {
  95         struct net *net = genl_info_net(info);
  96         struct seg6_pernet_data *sdata;
  97         struct seg6_hmac_info *hinfo;
  98         u32 hmackeyid;
  99         char *secret;
 100         int err = 0;
 101         u8 algid;
 102         u8 slen;
 103
 104         sdata = seg6_pernet(net);
 105
 106         if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
 107             !info->attrs[SEG6_ATTR_SECRETLEN] ||
 108             !info->attrs[SEG6_ATTR_ALGID])
 109                 return -EINVAL;
 110
 111         hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
 112         slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
 113         algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
 114
 115         if (hmackeyid == 0)
 116                 return -EINVAL;
 117
 118         if (slen > SEG6_HMAC_SECRET_LEN)
 119                 return -EINVAL;
 120
 121         mutex_lock(&sdata->lock);
 122         hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 123
 124         if (!slen) {
 125                 if (!hinfo)
 126                         err = -ENOENT;
 127
 128                 err = seg6_hmac_info_del(net, hmackeyid);
 129
 130                 goto out_unlock;
 131         }
 132
 133         if (!info->attrs[SEG6_ATTR_SECRET]) {
 134                 err = -EINVAL;
 135                 goto out_unlock;
 136         }
 137
 138         if (slen > nla_len(info->attrs[SEG6_ATTR_SECRET])) {
 139                 err = -EINVAL;
 140                 goto out_unlock;
 141         }
 142
 143         if (hinfo) {
 144                 err = seg6_hmac_info_del(net, hmackeyid);
 145                 if (err)
 146                         goto out_unlock;
 147         }
 148
 149         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 150
 151         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 152         if (!hinfo) {
 153                 err = -ENOMEM;
 154                 goto out_unlock;
 155         }
 156
 157         memcpy(hinfo->secret, secret, slen);
 158         hinfo->slen = slen;
 159         hinfo->alg_id = algid;
 160         hinfo->hmackeyid = hmackeyid;
 161
 162         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 163         if (err)
 164                 kfree(hinfo);
 165
 166 out_unlock:
 167         mutex_unlock(&sdata->lock);
 168         return err;
 169 }
 170
 171 #else
 172
 173 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 174 {
 175         return -ENOTSUPP;
 176 }
 177
 178 #endif
 179
 180 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 181 {
 182         struct net *net = genl_info_net(info);
 183         struct in6_addr *val, *t_old, *t_new;
 184         struct seg6_pernet_data *sdata;
 185
 186         sdata = seg6_pernet(net);
 187
 188         if (!info->attrs[SEG6_ATTR_DST])
 189                 return -EINVAL;
 190
 191         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 192         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 193         if (!t_new)
 194                 return -ENOMEM;
 195
 196         mutex_lock(&sdata->lock);
 197
 198         t_old = sdata->tun_src;
 199         rcu_assign_pointer(sdata->tun_src, t_new);
 200
 201         mutex_unlock(&sdata->lock);
 202
 203         synchronize_net();
 204         kfree(t_old);
 205
 206         return 0;
 207 }
 208
 209 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 210 {
 211         struct net *net = genl_info_net(info);
 212         struct in6_addr *tun_src;
 213         struct sk_buff *msg;
 214         void *hdr;
 215
 216         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 217         if (!msg)
 218                 return -ENOMEM;
 219
 220         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 221                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 222         if (!hdr)
 223                 goto free_msg;
 224
 225         rcu_read_lock();
 226         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 227
 228         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 229                 goto nla_put_failure;
 230
 231         rcu_read_unlock();
 232
 233         genlmsg_end(msg, hdr);
 234         return genlmsg_reply(msg, info);
 235
 236 nla_put_failure:
 237         rcu_read_unlock();
 238 free_msg:
 239         nlmsg_free(msg);
 240         return -ENOMEM;
 241 }
 242
 243 #ifdef CONFIG_IPV6_SEG6_HMAC
 244
 245 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
 246                                  struct sk_buff *msg)
 247 {
 248         if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
 249             nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
 250             nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
 251             nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
 252                 return -1;
 253
 254         return 0;
 255 }
 256
 257 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
 258                                         u32 portid, u32 seq, u32 flags,
 259                                         struct sk_buff *skb, u8 cmd)
 260 {
 261         void *hdr;
 262
 263         hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
 264         if (!hdr)
 265                 return -ENOMEM;
 266
 267         if (__seg6_hmac_fill_info(hinfo, skb) < 0)
 268                 goto nla_put_failure;
 269
 270         genlmsg_end(skb, hdr);
 271         return 0;
 272
 273 nla_put_failure:
 274         genlmsg_cancel(skb, hdr);
 275         return -EMSGSIZE;
 276 }
 277
 278 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 279 {
 280         struct net *net = sock_net(cb->skb->sk);
 281         struct seg6_pernet_data *sdata;
 282         struct rhashtable_iter *iter;
 283
 284         sdata = seg6_pernet(net);
 285         iter = (struct rhashtable_iter *)cb->args[0];
 286
 287         if (!iter) {
 288                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 289                 if (!iter)
 290                         return -ENOMEM;
 291
 292                 cb->args[0] = (long)iter;
 293         }
 294
 295         rhashtable_walk_enter(&sdata->hmac_infos, iter);
 296
 297         return 0;
 298 }
 299
 300 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 301 {
 302         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 303
 304         rhashtable_walk_exit(iter);
 305
 306         kfree(iter);
 307
 308         return 0;
 309 }
 310
 311 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 312 {
 313         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 314         struct seg6_hmac_info *hinfo;
 315         int ret;
 316
 317         rhashtable_walk_start(iter);
 318
 319         for (;;) {
 320                 hinfo = rhashtable_walk_next(iter);
 321
 322                 if (IS_ERR(hinfo)) {
 323                         if (PTR_ERR(hinfo) == -EAGAIN)
 324                                 continue;
 325                         ret = PTR_ERR(hinfo);
 326                         goto done;
 327                 } else if (!hinfo) {
 328                         break;
 329                 }
 330
 331                 ret = __seg6_genl_dumphmac_element(hinfo,
 332                                                    NETLINK_CB(cb->skb).portid,
 333                                                    cb->nlh->nlmsg_seq,
 334                                                    NLM_F_MULTI,
 335                                                    skb, SEG6_CMD_DUMPHMAC);
 336                 if (ret)
 337                         goto done;
 338         }
 339
 340         ret = skb->len;
 341
 342 done:
 343         rhashtable_walk_stop(iter);
 344         return ret;
 345 }
 346
 347 #else
 348
 349 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 350 {
 351         return 0;
 352 }
 353
 354 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 355 {
 356         return 0;
 357 }
 358
 359 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 360 {
 361         return -ENOTSUPP;
 362 }
 363
 364 #endif
 365
 366 static int __net_init seg6_net_init(struct net *net)
 367 {
 368         struct seg6_pernet_data *sdata;
 369
 370         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 371         if (!sdata)
 372                 return -ENOMEM;
 373
 374         mutex_init(&sdata->lock);
 375
 376         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 377         if (!sdata->tun_src) {
 378                 kfree(sdata);
 379                 return -ENOMEM;
 380         }
 381
 382         net->ipv6.seg6_data = sdata;
 383
 384 #ifdef CONFIG_IPV6_SEG6_HMAC
 385         seg6_hmac_net_init(net);
 386 #endif
 387
 388         return 0;
 389 }
 390
 391 static void __net_exit seg6_net_exit(struct net *net)
 392 {
 393         struct seg6_pernet_data *sdata = seg6_pernet(net);
 394
 395 #ifdef CONFIG_IPV6_SEG6_HMAC
 396         seg6_hmac_net_exit(net);
 397 #endif
 398
 399         kfree(sdata->tun_src);
 400         kfree(sdata);
 401 }
 402
 403 static struct pernet_operations ip6_segments_ops = {
 404         .init = seg6_net_init,
 405         .exit = seg6_net_exit,
 406 };
 407
 408 static const struct genl_ops seg6_genl_ops[] = {
 409         {
 410                 .cmd    = SEG6_CMD_SETHMAC,
 411                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 412                 .doit   = seg6_genl_sethmac,
 413                 .flags  = GENL_ADMIN_PERM,
 414         },
 415         {
 416                 .cmd    = SEG6_CMD_DUMPHMAC,
 417                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 418                 .start  = seg6_genl_dumphmac_start,
 419                 .dumpit = seg6_genl_dumphmac,
 420                 .done   = seg6_genl_dumphmac_done,
 421                 .flags  = GENL_ADMIN_PERM,
 422         },
 423         {
 424                 .cmd    = SEG6_CMD_SET_TUNSRC,
 425                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 426                 .doit   = seg6_genl_set_tunsrc,
 427                 .flags  = GENL_ADMIN_PERM,
 428         },
 429         {
 430                 .cmd    = SEG6_CMD_GET_TUNSRC,
 431                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 432                 .doit   = seg6_genl_get_tunsrc,
 433                 .flags  = GENL_ADMIN_PERM,
 434         },
 435 };
 436
 437 static struct genl_family seg6_genl_family __ro_after_init = {
 438         .hdrsize        = 0,
 439         .name           = SEG6_GENL_NAME,
 440         .version        = SEG6_GENL_VERSION,
 441         .maxattr        = SEG6_ATTR_MAX,
 442         .policy = seg6_genl_policy,
 443         .netnsok        = true,
 444         .parallel_ops   = true,
 445         .ops            = seg6_genl_ops,
 446         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 447         .module         = THIS_MODULE,
 448 };
 449
 450 int __init seg6_init(void)
 451 {
 452         int err;
 453
 454         err = genl_register_family(&seg6_genl_family);
 455         if (err)
 456                 goto out;
 457
 458         err = register_pernet_subsys(&ip6_segments_ops);
 459         if (err)
 460                 goto out_unregister_genl;
 461
 462 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 463         err = seg6_iptunnel_init();
 464         if (err)
 465                 goto out_unregister_pernet;
 466
 467         err = seg6_local_init();
 468         if (err)
 469                 goto out_unregister_pernet;
 470 #endif
 471
 472 #ifdef CONFIG_IPV6_SEG6_HMAC
 473         err = seg6_hmac_init();
 474         if (err)
 475                 goto out_unregister_iptun;
 476 #endif
 477
 478         pr_info("Segment Routing with IPv6\n");
 479
 480 out:
 481         return err;
 482 #ifdef CONFIG_IPV6_SEG6_HMAC
 483 out_unregister_iptun:
 484 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 485         seg6_local_exit();
 486         seg6_iptunnel_exit();
 487 #endif
 488 #endif
 489 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 490 out_unregister_pernet:
 491         unregister_pernet_subsys(&ip6_segments_ops);
 492 #endif
 493 out_unregister_genl:
 494         genl_unregister_family(&seg6_genl_family);
 495         goto out;
 496 }
 497
 498 void seg6_exit(void)
 499 {
 500 #ifdef CONFIG_IPV6_SEG6_HMAC
 501         seg6_hmac_exit();
 502 #endif
 503 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 504         seg6_iptunnel_exit();
 505 #endif
 506         unregister_pernet_subsys(&ip6_segments_ops);
 507         genl_unregister_family(&seg6_genl_family);
 508 }