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