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 #include <linux/rhashtable.h>
  21
  22 #include <net/ipv6.h>
  23 #include <net/protocol.h>
  24
  25 #include <net/seg6.h>
  26 #include <net/genetlink.h>
  27 #include <linux/seg6.h>
  28 #include <linux/seg6_genl.h>
  29 #ifdef CONFIG_IPV6_SEG6_HMAC
  30 #include <net/seg6_hmac.h>
  31 #endif
  32
  33 bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
  34 {
  35         int trailing;
  36         unsigned int tlv_offset;
  37
  38         if (srh->type != IPV6_SRCRT_TYPE_4)
  39                 return false;
  40
  41         if (((srh->hdrlen + 1) << 3) != len)
  42                 return false;
  43
  44         if (srh->segments_left > srh->first_segment)
  45                 return false;
  46
  47         tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
  48
  49         trailing = len - tlv_offset;
  50         if (trailing < 0)
  51                 return false;
  52
  53         while (trailing) {
  54                 struct sr6_tlv *tlv;
  55                 unsigned int tlv_len;
  56
  57                 if (trailing < sizeof(*tlv))
  58                         return false;
  59
  60                 tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
  61                 tlv_len = sizeof(*tlv) + tlv->len;
  62
  63                 trailing -= tlv_len;
  64                 if (trailing < 0)
  65                         return false;
  66
  67                 tlv_offset += tlv_len;
  68         }
  69
  70         return true;
  71 }
  72
  73 static struct genl_family seg6_genl_family;
  74
  75 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
  76         [SEG6_ATTR_DST]                         = { .type = NLA_BINARY,
  77                 .len = sizeof(struct in6_addr) },
  78         [SEG6_ATTR_DSTLEN]                      = { .type = NLA_S32, },
  79         [SEG6_ATTR_HMACKEYID]           = { .type = NLA_U32, },
  80         [SEG6_ATTR_SECRET]                      = { .type = NLA_BINARY, },
  81         [SEG6_ATTR_SECRETLEN]           = { .type = NLA_U8, },
  82         [SEG6_ATTR_ALGID]                       = { .type = NLA_U8, },
  83         [SEG6_ATTR_HMACINFO]            = { .type = NLA_NESTED, },
  84 };
  85
  86 #ifdef CONFIG_IPV6_SEG6_HMAC
  87
  88 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
  89 {
  90         struct net *net = genl_info_net(info);
  91         struct seg6_pernet_data *sdata;
  92         struct seg6_hmac_info *hinfo;
  93         u32 hmackeyid;
  94         char *secret;
  95         int err = 0;
  96         u8 algid;
  97         u8 slen;
  98
  99         sdata = seg6_pernet(net);
 100
 101         if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
 102             !info->attrs[SEG6_ATTR_SECRETLEN] ||
 103             !info->attrs[SEG6_ATTR_ALGID])
 104                 return -EINVAL;
 105
 106         hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
 107         slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
 108         algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
 109
 110         if (hmackeyid == 0)
 111                 return -EINVAL;
 112
 113         if (slen > SEG6_HMAC_SECRET_LEN)
 114                 return -EINVAL;
 115
 116         mutex_lock(&sdata->lock);
 117         hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 118
 119         if (!slen) {
 120                 if (!hinfo)
 121                         err = -ENOENT;
 122
 123                 err = seg6_hmac_info_del(net, hmackeyid);
 124
 125                 goto out_unlock;
 126         }
 127
 128         if (!info->attrs[SEG6_ATTR_SECRET]) {
 129                 err = -EINVAL;
 130                 goto out_unlock;
 131         }
 132
 133         if (hinfo) {
 134                 err = seg6_hmac_info_del(net, hmackeyid);
 135                 if (err)
 136                         goto out_unlock;
 137         }
 138
 139         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 140
 141         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 142         if (!hinfo) {
 143                 err = -ENOMEM;
 144                 goto out_unlock;
 145         }
 146
 147         memcpy(hinfo->secret, secret, slen);
 148         hinfo->slen = slen;
 149         hinfo->alg_id = algid;
 150         hinfo->hmackeyid = hmackeyid;
 151
 152         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 153         if (err)
 154                 kfree(hinfo);
 155
 156 out_unlock:
 157         mutex_unlock(&sdata->lock);
 158         return err;
 159 }
 160
 161 #else
 162
 163 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 164 {
 165         return -ENOTSUPP;
 166 }
 167
 168 #endif
 169
 170 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 171 {
 172         struct net *net = genl_info_net(info);
 173         struct in6_addr *val, *t_old, *t_new;
 174         struct seg6_pernet_data *sdata;
 175
 176         sdata = seg6_pernet(net);
 177
 178         if (!info->attrs[SEG6_ATTR_DST])
 179                 return -EINVAL;
 180
 181         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 182         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 183         if (!t_new)
 184                 return -ENOMEM;
 185
 186         mutex_lock(&sdata->lock);
 187
 188         t_old = sdata->tun_src;
 189         rcu_assign_pointer(sdata->tun_src, t_new);
 190
 191         mutex_unlock(&sdata->lock);
 192
 193         synchronize_net();
 194         kfree(t_old);
 195
 196         return 0;
 197 }
 198
 199 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 200 {
 201         struct net *net = genl_info_net(info);
 202         struct in6_addr *tun_src;
 203         struct sk_buff *msg;
 204         void *hdr;
 205
 206         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 207         if (!msg)
 208                 return -ENOMEM;
 209
 210         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 211                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 212         if (!hdr)
 213                 goto free_msg;
 214
 215         rcu_read_lock();
 216         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 217
 218         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 219                 goto nla_put_failure;
 220
 221         rcu_read_unlock();
 222
 223         genlmsg_end(msg, hdr);
 224         return genlmsg_reply(msg, info);
 225
 226 nla_put_failure:
 227         rcu_read_unlock();
 228 free_msg:
 229         nlmsg_free(msg);
 230         return -ENOMEM;
 231 }
 232
 233 #ifdef CONFIG_IPV6_SEG6_HMAC
 234
 235 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
 236                                  struct sk_buff *msg)
 237 {
 238         if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
 239             nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
 240             nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
 241             nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
 242                 return -1;
 243
 244         return 0;
 245 }
 246
 247 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
 248                                         u32 portid, u32 seq, u32 flags,
 249                                         struct sk_buff *skb, u8 cmd)
 250 {
 251         void *hdr;
 252
 253         hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
 254         if (!hdr)
 255                 return -ENOMEM;
 256
 257         if (__seg6_hmac_fill_info(hinfo, skb) < 0)
 258                 goto nla_put_failure;
 259
 260         genlmsg_end(skb, hdr);
 261         return 0;
 262
 263 nla_put_failure:
 264         genlmsg_cancel(skb, hdr);
 265         return -EMSGSIZE;
 266 }
 267
 268 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 269 {
 270         struct net *net = sock_net(cb->skb->sk);
 271         struct seg6_pernet_data *sdata;
 272         struct rhashtable_iter *iter;
 273
 274         sdata = seg6_pernet(net);
 275         iter = (struct rhashtable_iter *)cb->args[0];
 276
 277         if (!iter) {
 278                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 279                 if (!iter)
 280                         return -ENOMEM;
 281
 282                 cb->args[0] = (long)iter;
 283         }
 284
 285         rhashtable_walk_enter(&sdata->hmac_infos, iter);
 286
 287         return 0;
 288 }
 289
 290 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 291 {
 292         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 293
 294         rhashtable_walk_exit(iter);
 295
 296         kfree(iter);
 297
 298         return 0;
 299 }
 300
 301 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 302 {
 303         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 304         struct seg6_hmac_info *hinfo;
 305         int ret;
 306
 307         rhashtable_walk_start(iter);
 308
 309         for (;;) {
 310                 hinfo = rhashtable_walk_next(iter);
 311
 312                 if (IS_ERR(hinfo)) {
 313                         if (PTR_ERR(hinfo) == -EAGAIN)
 314                                 continue;
 315                         ret = PTR_ERR(hinfo);
 316                         goto done;
 317                 } else if (!hinfo) {
 318                         break;
 319                 }
 320
 321                 ret = __seg6_genl_dumphmac_element(hinfo,
 322                                                    NETLINK_CB(cb->skb).portid,
 323                                                    cb->nlh->nlmsg_seq,
 324                                                    NLM_F_MULTI,
 325                                                    skb, SEG6_CMD_DUMPHMAC);
 326                 if (ret)
 327                         goto done;
 328         }
 329
 330         ret = skb->len;
 331
 332 done:
 333         rhashtable_walk_stop(iter);
 334         return ret;
 335 }
 336
 337 #else
 338
 339 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 340 {
 341         return 0;
 342 }
 343
 344 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 345 {
 346         return 0;
 347 }
 348
 349 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 350 {
 351         return -ENOTSUPP;
 352 }
 353
 354 #endif
 355
 356 static int __net_init seg6_net_init(struct net *net)
 357 {
 358         struct seg6_pernet_data *sdata;
 359
 360         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 361         if (!sdata)
 362                 return -ENOMEM;
 363
 364         mutex_init(&sdata->lock);
 365
 366         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 367         if (!sdata->tun_src) {
 368                 kfree(sdata);
 369                 return -ENOMEM;
 370         }
 371
 372         net->ipv6.seg6_data = sdata;
 373
 374 #ifdef CONFIG_IPV6_SEG6_HMAC
 375         seg6_hmac_net_init(net);
 376 #endif
 377
 378         return 0;
 379 }
 380
 381 static void __net_exit seg6_net_exit(struct net *net)
 382 {
 383         struct seg6_pernet_data *sdata = seg6_pernet(net);
 384
 385 #ifdef CONFIG_IPV6_SEG6_HMAC
 386         seg6_hmac_net_exit(net);
 387 #endif
 388
 389         kfree(sdata->tun_src);
 390         kfree(sdata);
 391 }
 392
 393 static struct pernet_operations ip6_segments_ops = {
 394         .init = seg6_net_init,
 395         .exit = seg6_net_exit,
 396 };
 397
 398 static const struct genl_ops seg6_genl_ops[] = {
 399         {
 400                 .cmd    = SEG6_CMD_SETHMAC,
 401                 .doit   = seg6_genl_sethmac,
 402                 .policy = seg6_genl_policy,
 403                 .flags  = GENL_ADMIN_PERM,
 404         },
 405         {
 406                 .cmd    = SEG6_CMD_DUMPHMAC,
 407                 .start  = seg6_genl_dumphmac_start,
 408                 .dumpit = seg6_genl_dumphmac,
 409                 .done   = seg6_genl_dumphmac_done,
 410                 .policy = seg6_genl_policy,
 411                 .flags  = GENL_ADMIN_PERM,
 412         },
 413         {
 414                 .cmd    = SEG6_CMD_SET_TUNSRC,
 415                 .doit   = seg6_genl_set_tunsrc,
 416                 .policy = seg6_genl_policy,
 417                 .flags  = GENL_ADMIN_PERM,
 418         },
 419         {
 420                 .cmd    = SEG6_CMD_GET_TUNSRC,
 421                 .doit   = seg6_genl_get_tunsrc,
 422                 .policy = seg6_genl_policy,
 423                 .flags  = GENL_ADMIN_PERM,
 424         },
 425 };
 426
 427 static struct genl_family seg6_genl_family __ro_after_init = {
 428         .hdrsize        = 0,
 429         .name           = SEG6_GENL_NAME,
 430         .version        = SEG6_GENL_VERSION,
 431         .maxattr        = SEG6_ATTR_MAX,
 432         .netnsok        = true,
 433         .parallel_ops   = true,
 434         .ops            = seg6_genl_ops,
 435         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 436         .module         = THIS_MODULE,
 437 };
 438
 439 int __init seg6_init(void)
 440 {
 441         int err = -ENOMEM;
 442
 443         err = genl_register_family(&seg6_genl_family);
 444         if (err)
 445                 goto out;
 446
 447         err = register_pernet_subsys(&ip6_segments_ops);
 448         if (err)
 449                 goto out_unregister_genl;
 450
 451 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 452         err = seg6_iptunnel_init();
 453         if (err)
 454                 goto out_unregister_pernet;
 455
 456         err = seg6_local_init();
 457         if (err)
 458                 goto out_unregister_pernet;
 459 #endif
 460
 461 #ifdef CONFIG_IPV6_SEG6_HMAC
 462         err = seg6_hmac_init();
 463         if (err)
 464                 goto out_unregister_iptun;
 465 #endif
 466
 467         pr_info("Segment Routing with IPv6\n");
 468
 469 out:
 470         return err;
 471 #ifdef CONFIG_IPV6_SEG6_HMAC
 472 out_unregister_iptun:
 473 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 474         seg6_local_exit();
 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 }