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