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