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)
  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         max_last_entry = (srh->hdrlen / 2) - 1;
  41
  42         if (srh->first_segment > max_last_entry)
  43                 return false;
  44
  45         if (srh->segments_left > srh->first_segment + 1)
  46                 return false;
  47
  48         tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
  49
  50         trailing = len - tlv_offset;
  51         if (trailing < 0)
  52                 return false;
  53
  54         while (trailing) {
  55                 struct sr6_tlv *tlv;
  56                 unsigned int tlv_len;
  57
  58                 if (trailing < sizeof(*tlv))
  59                         return false;
  60
  61                 tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
  62                 tlv_len = sizeof(*tlv) + tlv->len;
  63
  64                 trailing -= tlv_len;
  65                 if (trailing < 0)
  66                         return false;
  67
  68                 tlv_offset += tlv_len;
  69         }
  70
  71         return true;
  72 }
  73
  74 static struct genl_family seg6_genl_family;
  75
  76 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
  77         [SEG6_ATTR_DST]                         = { .type = NLA_BINARY,
  78                 .len = sizeof(struct in6_addr) },
  79         [SEG6_ATTR_DSTLEN]                      = { .type = NLA_S32, },
  80         [SEG6_ATTR_HMACKEYID]           = { .type = NLA_U32, },
  81         [SEG6_ATTR_SECRET]                      = { .type = NLA_BINARY, },
  82         [SEG6_ATTR_SECRETLEN]           = { .type = NLA_U8, },
  83         [SEG6_ATTR_ALGID]                       = { .type = NLA_U8, },
  84         [SEG6_ATTR_HMACINFO]            = { .type = NLA_NESTED, },
  85 };
  86
  87 #ifdef CONFIG_IPV6_SEG6_HMAC
  88
  89 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
  90 {
  91         struct net *net = genl_info_net(info);
  92         struct seg6_pernet_data *sdata;
  93         struct seg6_hmac_info *hinfo;
  94         u32 hmackeyid;
  95         char *secret;
  96         int err = 0;
  97         u8 algid;
  98         u8 slen;
  99
 100         sdata = seg6_pernet(net);
 101
 102         if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
 103             !info->attrs[SEG6_ATTR_SECRETLEN] ||
 104             !info->attrs[SEG6_ATTR_ALGID])
 105                 return -EINVAL;
 106
 107         hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
 108         slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
 109         algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
 110
 111         if (hmackeyid == 0)
 112                 return -EINVAL;
 113
 114         if (slen > SEG6_HMAC_SECRET_LEN)
 115                 return -EINVAL;
 116
 117         mutex_lock(&sdata->lock);
 118         hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 119
 120         if (!slen) {
 121                 if (!hinfo)
 122                         err = -ENOENT;
 123
 124                 err = seg6_hmac_info_del(net, hmackeyid);
 125
 126                 goto out_unlock;
 127         }
 128
 129         if (!info->attrs[SEG6_ATTR_SECRET]) {
 130                 err = -EINVAL;
 131                 goto out_unlock;
 132         }
 133
 134         if (hinfo) {
 135                 err = seg6_hmac_info_del(net, hmackeyid);
 136                 if (err)
 137                         goto out_unlock;
 138         }
 139
 140         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 141
 142         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 143         if (!hinfo) {
 144                 err = -ENOMEM;
 145                 goto out_unlock;
 146         }
 147
 148         memcpy(hinfo->secret, secret, slen);
 149         hinfo->slen = slen;
 150         hinfo->alg_id = algid;
 151         hinfo->hmackeyid = hmackeyid;
 152
 153         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 154         if (err)
 155                 kfree(hinfo);
 156
 157 out_unlock:
 158         mutex_unlock(&sdata->lock);
 159         return err;
 160 }
 161
 162 #else
 163
 164 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 165 {
 166         return -ENOTSUPP;
 167 }
 168
 169 #endif
 170
 171 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 172 {
 173         struct net *net = genl_info_net(info);
 174         struct in6_addr *val, *t_old, *t_new;
 175         struct seg6_pernet_data *sdata;
 176
 177         sdata = seg6_pernet(net);
 178
 179         if (!info->attrs[SEG6_ATTR_DST])
 180                 return -EINVAL;
 181
 182         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 183         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 184         if (!t_new)
 185                 return -ENOMEM;
 186
 187         mutex_lock(&sdata->lock);
 188
 189         t_old = sdata->tun_src;
 190         rcu_assign_pointer(sdata->tun_src, t_new);
 191
 192         mutex_unlock(&sdata->lock);
 193
 194         synchronize_net();
 195         kfree(t_old);
 196
 197         return 0;
 198 }
 199
 200 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 201 {
 202         struct net *net = genl_info_net(info);
 203         struct in6_addr *tun_src;
 204         struct sk_buff *msg;
 205         void *hdr;
 206
 207         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 208         if (!msg)
 209                 return -ENOMEM;
 210
 211         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 212                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 213         if (!hdr)
 214                 goto free_msg;
 215
 216         rcu_read_lock();
 217         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 218
 219         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 220                 goto nla_put_failure;
 221
 222         rcu_read_unlock();
 223
 224         genlmsg_end(msg, hdr);
 225         return genlmsg_reply(msg, info);
 226
 227 nla_put_failure:
 228         rcu_read_unlock();
 229 free_msg:
 230         nlmsg_free(msg);
 231         return -ENOMEM;
 232 }
 233
 234 #ifdef CONFIG_IPV6_SEG6_HMAC
 235
 236 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
 237                                  struct sk_buff *msg)
 238 {
 239         if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
 240             nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
 241             nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
 242             nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
 243                 return -1;
 244
 245         return 0;
 246 }
 247
 248 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
 249                                         u32 portid, u32 seq, u32 flags,
 250                                         struct sk_buff *skb, u8 cmd)
 251 {
 252         void *hdr;
 253
 254         hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
 255         if (!hdr)
 256                 return -ENOMEM;
 257
 258         if (__seg6_hmac_fill_info(hinfo, skb) < 0)
 259                 goto nla_put_failure;
 260
 261         genlmsg_end(skb, hdr);
 262         return 0;
 263
 264 nla_put_failure:
 265         genlmsg_cancel(skb, hdr);
 266         return -EMSGSIZE;
 267 }
 268
 269 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 270 {
 271         struct net *net = sock_net(cb->skb->sk);
 272         struct seg6_pernet_data *sdata;
 273         struct rhashtable_iter *iter;
 274
 275         sdata = seg6_pernet(net);
 276         iter = (struct rhashtable_iter *)cb->args[0];
 277
 278         if (!iter) {
 279                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 280                 if (!iter)
 281                         return -ENOMEM;
 282
 283                 cb->args[0] = (long)iter;
 284         }
 285
 286         rhashtable_walk_enter(&sdata->hmac_infos, iter);
 287
 288         return 0;
 289 }
 290
 291 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 292 {
 293         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 294
 295         rhashtable_walk_exit(iter);
 296
 297         kfree(iter);
 298
 299         return 0;
 300 }
 301
 302 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 303 {
 304         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 305         struct seg6_hmac_info *hinfo;
 306         int ret;
 307
 308         rhashtable_walk_start(iter);
 309
 310         for (;;) {
 311                 hinfo = rhashtable_walk_next(iter);
 312
 313                 if (IS_ERR(hinfo)) {
 314                         if (PTR_ERR(hinfo) == -EAGAIN)
 315                                 continue;
 316                         ret = PTR_ERR(hinfo);
 317                         goto done;
 318                 } else if (!hinfo) {
 319                         break;
 320                 }
 321
 322                 ret = __seg6_genl_dumphmac_element(hinfo,
 323                                                    NETLINK_CB(cb->skb).portid,
 324                                                    cb->nlh->nlmsg_seq,
 325                                                    NLM_F_MULTI,
 326                                                    skb, SEG6_CMD_DUMPHMAC);
 327                 if (ret)
 328                         goto done;
 329         }
 330
 331         ret = skb->len;
 332
 333 done:
 334         rhashtable_walk_stop(iter);
 335         return ret;
 336 }
 337
 338 #else
 339
 340 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 341 {
 342         return 0;
 343 }
 344
 345 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 346 {
 347         return 0;
 348 }
 349
 350 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 351 {
 352         return -ENOTSUPP;
 353 }
 354
 355 #endif
 356
 357 static int __net_init seg6_net_init(struct net *net)
 358 {
 359         struct seg6_pernet_data *sdata;
 360
 361         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 362         if (!sdata)
 363                 return -ENOMEM;
 364
 365         mutex_init(&sdata->lock);
 366
 367         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 368         if (!sdata->tun_src) {
 369                 kfree(sdata);
 370                 return -ENOMEM;
 371         }
 372
 373         net->ipv6.seg6_data = sdata;
 374
 375 #ifdef CONFIG_IPV6_SEG6_HMAC
 376         seg6_hmac_net_init(net);
 377 #endif
 378
 379         return 0;
 380 }
 381
 382 static void __net_exit seg6_net_exit(struct net *net)
 383 {
 384         struct seg6_pernet_data *sdata = seg6_pernet(net);
 385
 386 #ifdef CONFIG_IPV6_SEG6_HMAC
 387         seg6_hmac_net_exit(net);
 388 #endif
 389
 390         kfree(sdata->tun_src);
 391         kfree(sdata);
 392 }
 393
 394 static struct pernet_operations ip6_segments_ops = {
 395         .init = seg6_net_init,
 396         .exit = seg6_net_exit,
 397 };
 398
 399 static const struct genl_ops seg6_genl_ops[] = {
 400         {
 401                 .cmd    = SEG6_CMD_SETHMAC,
 402                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 403                 .doit   = seg6_genl_sethmac,
 404                 .flags  = GENL_ADMIN_PERM,
 405         },
 406         {
 407                 .cmd    = SEG6_CMD_DUMPHMAC,
 408                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 409                 .start  = seg6_genl_dumphmac_start,
 410                 .dumpit = seg6_genl_dumphmac,
 411                 .done   = seg6_genl_dumphmac_done,
 412                 .flags  = GENL_ADMIN_PERM,
 413         },
 414         {
 415                 .cmd    = SEG6_CMD_SET_TUNSRC,
 416                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 417                 .doit   = seg6_genl_set_tunsrc,
 418                 .flags  = GENL_ADMIN_PERM,
 419         },
 420         {
 421                 .cmd    = SEG6_CMD_GET_TUNSRC,
 422                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 423                 .doit   = seg6_genl_get_tunsrc,
 424                 .flags  = GENL_ADMIN_PERM,
 425         },
 426 };
 427
 428 static struct genl_family seg6_genl_family __ro_after_init = {
 429         .hdrsize        = 0,
 430         .name           = SEG6_GENL_NAME,
 431         .version        = SEG6_GENL_VERSION,
 432         .maxattr        = SEG6_ATTR_MAX,
 433         .policy = seg6_genl_policy,
 434         .netnsok        = true,
 435         .parallel_ops   = true,
 436         .ops            = seg6_genl_ops,
 437         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 438         .module         = THIS_MODULE,
 439 };
 440
 441 int __init seg6_init(void)
 442 {
 443         int err;
 444
 445         err = genl_register_family(&seg6_genl_family);
 446         if (err)
 447                 goto out;
 448
 449         err = register_pernet_subsys(&ip6_segments_ops);
 450         if (err)
 451                 goto out_unregister_genl;
 452
 453 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 454         err = seg6_iptunnel_init();
 455         if (err)
 456                 goto out_unregister_pernet;
 457
 458         err = seg6_local_init();
 459         if (err)
 460                 goto out_unregister_pernet;
 461 #endif
 462
 463 #ifdef CONFIG_IPV6_SEG6_HMAC
 464         err = seg6_hmac_init();
 465         if (err)
 466                 goto out_unregister_iptun;
 467 #endif
 468
 469         pr_info("Segment Routing with IPv6\n");
 470
 471 out:
 472         return err;
 473 #ifdef CONFIG_IPV6_SEG6_HMAC
 474 out_unregister_iptun:
 475 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 476         seg6_local_exit();
 477         seg6_iptunnel_exit();
 478 #endif
 479 #endif
 480 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 481 out_unregister_pernet:
 482         unregister_pernet_subsys(&ip6_segments_ops);
 483 #endif
 484 out_unregister_genl:
 485         genl_unregister_family(&seg6_genl_family);
 486         goto out;
 487 }
 488
 489 void seg6_exit(void)
 490 {
 491 #ifdef CONFIG_IPV6_SEG6_HMAC
 492         seg6_hmac_exit();
 493 #endif
 494 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 495         seg6_iptunnel_exit();
 496 #endif
 497         unregister_pernet_subsys(&ip6_segments_ops);
 498         genl_unregister_family(&seg6_genl_family);
 499 }