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                 if (trailing < sizeof(*tlv))
  57                         return false;
  58
  59                 tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
  60                 tlv_len = sizeof(*tlv) + tlv->len;
  61
  62                 trailing -= tlv_len;
  63                 if (trailing < 0)
  64                         return false;
  65
  66                 tlv_offset += tlv_len;
  67         }
  68
  69         return true;
  70 }
  71
  72 static struct genl_family seg6_genl_family;
  73
  74 static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
  75         [SEG6_ATTR_DST]                         = { .type = NLA_BINARY,
  76                 .len = sizeof(struct in6_addr) },
  77         [SEG6_ATTR_DSTLEN]                      = { .type = NLA_S32, },
  78         [SEG6_ATTR_HMACKEYID]           = { .type = NLA_U32, },
  79         [SEG6_ATTR_SECRET]                      = { .type = NLA_BINARY, },
  80         [SEG6_ATTR_SECRETLEN]           = { .type = NLA_U8, },
  81         [SEG6_ATTR_ALGID]                       = { .type = NLA_U8, },
  82         [SEG6_ATTR_HMACINFO]            = { .type = NLA_NESTED, },
  83 };
  84
  85 #ifdef CONFIG_IPV6_SEG6_HMAC
  86
  87 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
  88 {
  89         struct net *net = genl_info_net(info);
  90         struct seg6_pernet_data *sdata;
  91         struct seg6_hmac_info *hinfo;
  92         u32 hmackeyid;
  93         char *secret;
  94         int err = 0;
  95         u8 algid;
  96         u8 slen;
  97
  98         sdata = seg6_pernet(net);
  99
 100         if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
 101             !info->attrs[SEG6_ATTR_SECRETLEN] ||
 102             !info->attrs[SEG6_ATTR_ALGID])
 103                 return -EINVAL;
 104
 105         hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
 106         slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
 107         algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
 108
 109         if (hmackeyid == 0)
 110                 return -EINVAL;
 111
 112         if (slen > SEG6_HMAC_SECRET_LEN)
 113                 return -EINVAL;
 114
 115         mutex_lock(&sdata->lock);
 116         hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 117
 118         if (!slen) {
 119                 if (!hinfo)
 120                         err = -ENOENT;
 121
 122                 err = seg6_hmac_info_del(net, hmackeyid);
 123
 124                 goto out_unlock;
 125         }
 126
 127         if (!info->attrs[SEG6_ATTR_SECRET]) {
 128                 err = -EINVAL;
 129                 goto out_unlock;
 130         }
 131
 132         if (slen > nla_len(info->attrs[SEG6_ATTR_SECRET])) {
 133                 err = -EINVAL;
 134                 goto out_unlock;
 135         }
 136
 137         if (hinfo) {
 138                 err = seg6_hmac_info_del(net, hmackeyid);
 139                 if (err)
 140                         goto out_unlock;
 141         }
 142
 143         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 144
 145         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 146         if (!hinfo) {
 147                 err = -ENOMEM;
 148                 goto out_unlock;
 149         }
 150
 151         memcpy(hinfo->secret, secret, slen);
 152         hinfo->slen = slen;
 153         hinfo->alg_id = algid;
 154         hinfo->hmackeyid = hmackeyid;
 155
 156         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 157         if (err)
 158                 kfree(hinfo);
 159
 160 out_unlock:
 161         mutex_unlock(&sdata->lock);
 162         return err;
 163 }
 164
 165 #else
 166
 167 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 168 {
 169         return -ENOTSUPP;
 170 }
 171
 172 #endif
 173
 174 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 175 {
 176         struct net *net = genl_info_net(info);
 177         struct in6_addr *val, *t_old, *t_new;
 178         struct seg6_pernet_data *sdata;
 179
 180         sdata = seg6_pernet(net);
 181
 182         if (!info->attrs[SEG6_ATTR_DST])
 183                 return -EINVAL;
 184
 185         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 186         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 187         if (!t_new)
 188                 return -ENOMEM;
 189
 190         mutex_lock(&sdata->lock);
 191
 192         t_old = sdata->tun_src;
 193         rcu_assign_pointer(sdata->tun_src, t_new);
 194
 195         mutex_unlock(&sdata->lock);
 196
 197         synchronize_net();
 198         kfree(t_old);
 199
 200         return 0;
 201 }
 202
 203 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 204 {
 205         struct net *net = genl_info_net(info);
 206         struct in6_addr *tun_src;
 207         struct sk_buff *msg;
 208         void *hdr;
 209
 210         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 211         if (!msg)
 212                 return -ENOMEM;
 213
 214         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 215                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 216         if (!hdr)
 217                 goto free_msg;
 218
 219         rcu_read_lock();
 220         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 221
 222         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 223                 goto nla_put_failure;
 224
 225         rcu_read_unlock();
 226
 227         genlmsg_end(msg, hdr);
 228         return genlmsg_reply(msg, info);
 229
 230 nla_put_failure:
 231         rcu_read_unlock();
 232         genlmsg_cancel(msg, hdr);
 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         ret = rhashtable_walk_start(iter);
 313         if (ret && ret != -EAGAIN)
 314                 goto done;
 315
 316         for (;;) {
 317                 hinfo = rhashtable_walk_next(iter);
 318
 319                 if (IS_ERR(hinfo)) {
 320                         if (PTR_ERR(hinfo) == -EAGAIN)
 321                                 continue;
 322                         ret = PTR_ERR(hinfo);
 323                         goto done;
 324                 } else if (!hinfo) {
 325                         break;
 326                 }
 327
 328                 ret = __seg6_genl_dumphmac_element(hinfo,
 329                                                    NETLINK_CB(cb->skb).portid,
 330                                                    cb->nlh->nlmsg_seq,
 331                                                    NLM_F_MULTI,
 332                                                    skb, SEG6_CMD_DUMPHMAC);
 333                 if (ret)
 334                         goto done;
 335         }
 336
 337         ret = skb->len;
 338
 339 done:
 340         rhashtable_walk_stop(iter);
 341         return ret;
 342 }
 343
 344 #else
 345
 346 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 347 {
 348         return 0;
 349 }
 350
 351 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 352 {
 353         return 0;
 354 }
 355
 356 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 357 {
 358         return -ENOTSUPP;
 359 }
 360
 361 #endif
 362
 363 static int __net_init seg6_net_init(struct net *net)
 364 {
 365         struct seg6_pernet_data *sdata;
 366
 367         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 368         if (!sdata)
 369                 return -ENOMEM;
 370
 371         mutex_init(&sdata->lock);
 372
 373         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 374         if (!sdata->tun_src) {
 375                 kfree(sdata);
 376                 return -ENOMEM;
 377         }
 378
 379         net->ipv6.seg6_data = sdata;
 380
 381 #ifdef CONFIG_IPV6_SEG6_HMAC
 382         seg6_hmac_net_init(net);
 383 #endif
 384
 385         return 0;
 386 }
 387
 388 static void __net_exit seg6_net_exit(struct net *net)
 389 {
 390         struct seg6_pernet_data *sdata = seg6_pernet(net);
 391
 392 #ifdef CONFIG_IPV6_SEG6_HMAC
 393         seg6_hmac_net_exit(net);
 394 #endif
 395
 396         kfree(sdata->tun_src);
 397         kfree(sdata);
 398 }
 399
 400 static struct pernet_operations ip6_segments_ops = {
 401         .init = seg6_net_init,
 402         .exit = seg6_net_exit,
 403 };
 404
 405 static const struct genl_ops seg6_genl_ops[] = {
 406         {
 407                 .cmd    = SEG6_CMD_SETHMAC,
 408                 .doit   = seg6_genl_sethmac,
 409                 .policy = seg6_genl_policy,
 410                 .flags  = GENL_ADMIN_PERM,
 411         },
 412         {
 413                 .cmd    = SEG6_CMD_DUMPHMAC,
 414                 .start  = seg6_genl_dumphmac_start,
 415                 .dumpit = seg6_genl_dumphmac,
 416                 .done   = seg6_genl_dumphmac_done,
 417                 .policy = seg6_genl_policy,
 418                 .flags  = GENL_ADMIN_PERM,
 419         },
 420         {
 421                 .cmd    = SEG6_CMD_SET_TUNSRC,
 422                 .doit   = seg6_genl_set_tunsrc,
 423                 .policy = seg6_genl_policy,
 424                 .flags  = GENL_ADMIN_PERM,
 425         },
 426         {
 427                 .cmd    = SEG6_CMD_GET_TUNSRC,
 428                 .doit   = seg6_genl_get_tunsrc,
 429                 .policy = seg6_genl_policy,
 430                 .flags  = GENL_ADMIN_PERM,
 431         },
 432 };
 433
 434 static struct genl_family seg6_genl_family __ro_after_init = {
 435         .hdrsize        = 0,
 436         .name           = SEG6_GENL_NAME,
 437         .version        = SEG6_GENL_VERSION,
 438         .maxattr        = SEG6_ATTR_MAX,
 439         .netnsok        = true,
 440         .parallel_ops   = true,
 441         .ops            = seg6_genl_ops,
 442         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 443         .module         = THIS_MODULE,
 444 };
 445
 446 int __init seg6_init(void)
 447 {
 448         int err = -ENOMEM;
 449
 450         err = genl_register_family(&seg6_genl_family);
 451         if (err)
 452                 goto out;
 453
 454         err = register_pernet_subsys(&ip6_segments_ops);
 455         if (err)
 456                 goto out_unregister_genl;
 457
 458 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 459         err = seg6_iptunnel_init();
 460         if (err)
 461                 goto out_unregister_pernet;
 462
 463         err = seg6_local_init();
 464         if (err)
 465                 goto out_unregister_pernet;
 466 #endif
 467
 468 #ifdef CONFIG_IPV6_SEG6_HMAC
 469         err = seg6_hmac_init();
 470         if (err)
 471                 goto out_unregister_iptun;
 472 #endif
 473
 474         pr_info("Segment Routing with IPv6\n");
 475
 476 out:
 477         return err;
 478 #ifdef CONFIG_IPV6_SEG6_HMAC
 479 out_unregister_iptun:
 480 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 481         seg6_local_exit();
 482         seg6_iptunnel_exit();
 483 #endif
 484 #endif
 485 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 486 out_unregister_pernet:
 487         unregister_pernet_subsys(&ip6_segments_ops);
 488 #endif
 489 out_unregister_genl:
 490         genl_unregister_family(&seg6_genl_family);
 491         goto out;
 492 }
 493
 494 void seg6_exit(void)
 495 {
 496 #ifdef CONFIG_IPV6_SEG6_HMAC
 497         seg6_hmac_exit();
 498 #endif
 499 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 500         seg6_iptunnel_exit();
 501 #endif
 502         unregister_pernet_subsys(&ip6_segments_ops);
 503         genl_unregister_family(&seg6_genl_family);
 504 }