net/ipv6/seg6.c

   1 /*
   2  *  SR-IPv6 implementation
   3  *
   4  *  Author:
   5  *  David Lebrun <david.lebrun@uclouvain.be>
   6  *
   7  *
   8  *  This program is free software; you can redistribute it and/or
   9  *        modify it under the terms of the GNU General Public License
  10  *        as published by the Free Software Foundation; either version
  11  *        2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/errno.h>
  15 #include <linux/types.h>
  16 #include <linux/socket.h>
  17 #include <linux/net.h>
  18 #include <linux/in6.h>
  19 #include <linux/slab.h>
  20
  21 #include <net/ipv6.h>
  22 #include <net/protocol.h>
  23
  24 #include <net/seg6.h>
  25 #include <net/genetlink.h>
  26 #include <linux/seg6.h>
  27 #include <linux/seg6_genl.h>
  28 #ifdef CONFIG_IPV6_SEG6_HMAC
  29 #include <net/seg6_hmac.h>
  30 #endif
  31
  32 bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
  33 {
  34         int trailing;
  35         unsigned int tlv_offset;
  36
  37         if (srh->type != IPV6_SRCRT_TYPE_4)
  38                 return false;
  39
  40         if (((srh->hdrlen + 1) << 3) != len)
  41                 return false;
  42
  43         if (srh->segments_left != srh->first_segment)
  44                 return false;
  45
  46         tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
  47
  48         trailing = len - tlv_offset;
  49         if (trailing < 0)
  50                 return false;
  51
  52         while (trailing) {
  53                 struct sr6_tlv *tlv;
  54                 unsigned int tlv_len;
  55
  56                 tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
  57                 tlv_len = sizeof(*tlv) + tlv->len;
  58
  59                 trailing -= tlv_len;
  60                 if (trailing < 0)
  61                         return false;
  62
  63                 tlv_offset += tlv_len;
  64         }
  65
  66         return true;
  67 }
  68
  69 static struct genl_family seg6_genl_family;
  70
  71 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
  72         [SEG6_ATTR_DST]                         = { .type = NLA_BINARY,
  73                 .len = sizeof(struct in6_addr) },
  74         [SEG6_ATTR_DSTLEN]                      = { .type = NLA_S32, },
  75         [SEG6_ATTR_HMACKEYID]           = { .type = NLA_U32, },
  76         [SEG6_ATTR_SECRET]                      = { .type = NLA_BINARY, },
  77         [SEG6_ATTR_SECRETLEN]           = { .type = NLA_U8, },
  78         [SEG6_ATTR_ALGID]                       = { .type = NLA_U8, },
  79         [SEG6_ATTR_HMACINFO]            = { .type = NLA_NESTED, },
  80 };
  81
  82 #ifdef CONFIG_IPV6_SEG6_HMAC
  83
  84 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
  85 {
  86         struct net *net = genl_info_net(info);
  87         struct seg6_pernet_data *sdata;
  88         struct seg6_hmac_info *hinfo;
  89         u32 hmackeyid;
  90         char *secret;
  91         int err = 0;
  92         u8 algid;
  93         u8 slen;
  94
  95         sdata = seg6_pernet(net);
  96
  97         if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
  98             !info->attrs[SEG6_ATTR_SECRETLEN] ||
  99             !info->attrs[SEG6_ATTR_ALGID])
 100                 return -EINVAL;
 101
 102         hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
 103         slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
 104         algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
 105
 106         if (hmackeyid == 0)
 107                 return -EINVAL;
 108
 109         if (slen > SEG6_HMAC_SECRET_LEN)
 110                 return -EINVAL;
 111
 112         mutex_lock(&sdata->lock);
 113         hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 114
 115         if (!slen) {
 116                 if (!hinfo)
 117                         err = -ENOENT;
 118
 119                 err = seg6_hmac_info_del(net, hmackeyid);
 120
 121                 goto out_unlock;
 122         }
 123
 124         if (!info->attrs[SEG6_ATTR_SECRET]) {
 125                 err = -EINVAL;
 126                 goto out_unlock;
 127         }
 128
 129         if (hinfo) {
 130                 err = seg6_hmac_info_del(net, hmackeyid);
 131                 if (err)
 132                         goto out_unlock;
 133         }
 134
 135         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 136
 137         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 138         if (!hinfo) {
 139                 err = -ENOMEM;
 140                 goto out_unlock;
 141         }
 142
 143         memcpy(hinfo->secret, secret, slen);
 144         hinfo->slen = slen;
 145         hinfo->alg_id = algid;
 146         hinfo->hmackeyid = hmackeyid;
 147
 148         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 149         if (err)
 150                 kfree(hinfo);
 151
 152 out_unlock:
 153         mutex_unlock(&sdata->lock);
 154         return err;
 155 }
 156
 157 #else
 158
 159 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 160 {
 161         return -ENOTSUPP;
 162 }
 163
 164 #endif
 165
 166 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 167 {
 168         struct net *net = genl_info_net(info);
 169         struct in6_addr *val, *t_old, *t_new;
 170         struct seg6_pernet_data *sdata;
 171
 172         sdata = seg6_pernet(net);
 173
 174         if (!info->attrs[SEG6_ATTR_DST])
 175                 return -EINVAL;
 176
 177         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 178         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 179         if (!t_new)
 180                 return -ENOMEM;
 181
 182         mutex_lock(&sdata->lock);
 183
 184         t_old = sdata->tun_src;
 185         rcu_assign_pointer(sdata->tun_src, t_new);
 186
 187         mutex_unlock(&sdata->lock);
 188
 189         synchronize_net();
 190         kfree(t_old);
 191
 192         return 0;
 193 }
 194
 195 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 196 {
 197         struct net *net = genl_info_net(info);
 198         struct in6_addr *tun_src;
 199         struct sk_buff *msg;
 200         void *hdr;
 201
 202         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 203         if (!msg)
 204                 return -ENOMEM;
 205
 206         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 207                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 208         if (!hdr)
 209                 goto free_msg;
 210
 211         rcu_read_lock();
 212         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 213
 214         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 215                 goto nla_put_failure;
 216
 217         rcu_read_unlock();
 218
 219         genlmsg_end(msg, hdr);
 220         genlmsg_reply(msg, info);
 221
 222         return 0;
 223
 224 nla_put_failure:
 225         rcu_read_unlock();
 226         genlmsg_cancel(msg, hdr);
 227 free_msg:
 228         nlmsg_free(msg);
 229         return -ENOMEM;
 230 }
 231
 232 #ifdef CONFIG_IPV6_SEG6_HMAC
 233
 234 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
 235                                  struct sk_buff *msg)
 236 {
 237         if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
 238             nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
 239             nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
 240             nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
 241                 return -1;
 242
 243         return 0;
 244 }
 245
 246 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
 247                                         u32 portid, u32 seq, u32 flags,
 248                                         struct sk_buff *skb, u8 cmd)
 249 {
 250         void *hdr;
 251
 252         hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
 253         if (!hdr)
 254                 return -ENOMEM;
 255
 256         if (__seg6_hmac_fill_info(hinfo, skb) < 0)
 257                 goto nla_put_failure;
 258
 259         genlmsg_end(skb, hdr);
 260         return 0;
 261
 262 nla_put_failure:
 263         genlmsg_cancel(skb, hdr);
 264         return -EMSGSIZE;
 265 }
 266
 267 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 268 {
 269         struct net *net = sock_net(cb->skb->sk);
 270         struct seg6_pernet_data *sdata;
 271         struct rhashtable_iter *iter;
 272
 273         sdata = seg6_pernet(net);
 274         iter = (struct rhashtable_iter *)cb->args[0];
 275
 276         if (!iter) {
 277                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 278                 if (!iter)
 279                         return -ENOMEM;
 280
 281                 cb->args[0] = (long)iter;
 282         }
 283
 284         rhashtable_walk_enter(&sdata->hmac_infos, iter);
 285
 286         return 0;
 287 }
 288
 289 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 290 {
 291         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 292
 293         rhashtable_walk_exit(iter);
 294
 295         kfree(iter);
 296
 297         return 0;
 298 }
 299
 300 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 301 {
 302         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 303         struct net *net = sock_net(skb->sk);
 304         struct seg6_pernet_data *sdata;
 305         struct seg6_hmac_info *hinfo;
 306         int ret;
 307
 308         sdata = seg6_pernet(net);
 309
 310         ret = rhashtable_walk_start(iter);
 311         if (ret && ret != -EAGAIN)
 312                 goto done;
 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                 .doit   = seg6_genl_sethmac,
 407                 .policy = seg6_genl_policy,
 408                 .flags  = GENL_ADMIN_PERM,
 409         },
 410         {
 411                 .cmd    = SEG6_CMD_DUMPHMAC,
 412                 .start  = seg6_genl_dumphmac_start,
 413                 .dumpit = seg6_genl_dumphmac,
 414                 .done   = seg6_genl_dumphmac_done,
 415                 .policy = seg6_genl_policy,
 416                 .flags  = GENL_ADMIN_PERM,
 417         },
 418         {
 419                 .cmd    = SEG6_CMD_SET_TUNSRC,
 420                 .doit   = seg6_genl_set_tunsrc,
 421                 .policy = seg6_genl_policy,
 422                 .flags  = GENL_ADMIN_PERM,
 423         },
 424         {
 425                 .cmd    = SEG6_CMD_GET_TUNSRC,
 426                 .doit   = seg6_genl_get_tunsrc,
 427                 .policy = seg6_genl_policy,
 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         .netnsok        = true,
 438         .parallel_ops   = true,
 439         .ops            = seg6_genl_ops,
 440         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 441         .module         = THIS_MODULE,
 442 };
 443
 444 int __init seg6_init(void)
 445 {
 446         int err = -ENOMEM;
 447
 448         err = genl_register_family(&seg6_genl_family);
 449         if (err)
 450                 goto out;
 451
 452         err = register_pernet_subsys(&ip6_segments_ops);
 453         if (err)
 454                 goto out_unregister_genl;
 455
 456 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 457         err = seg6_iptunnel_init();
 458         if (err)
 459                 goto out_unregister_pernet;
 460 #endif
 461
 462 #ifdef CONFIG_IPV6_SEG6_HMAC
 463         err = seg6_hmac_init();
 464         if (err)
 465                 goto out_unregister_iptun;
 466 #endif
 467
 468         pr_info("Segment Routing with IPv6\n");
 469
 470 out:
 471         return err;
 472 #ifdef CONFIG_IPV6_SEG6_HMAC
 473 out_unregister_iptun:
 474 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 475         seg6_iptunnel_exit();
 476 #endif
 477 #endif
 478 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 479 out_unregister_pernet:
 480         unregister_pernet_subsys(&ip6_segments_ops);
 481 #endif
 482 out_unregister_genl:
 483         genl_unregister_family(&seg6_genl_family);
 484         goto out;
 485 }
 486
 487 void seg6_exit(void)
 488 {
 489 #ifdef CONFIG_IPV6_SEG6_HMAC
 490         seg6_hmac_exit();
 491 #endif
 492 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 493         seg6_iptunnel_exit();
 494 #endif
 495         unregister_pernet_subsys(&ip6_segments_ops);
 496         genl_unregister_family(&seg6_genl_family);
 497 }