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         genlmsg_reply(msg, info);
 225
 226         return 0;
 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                 .doit   = seg6_genl_sethmac,
 404                 .policy = seg6_genl_policy,
 405                 .flags  = GENL_ADMIN_PERM,
 406         },
 407         {
 408                 .cmd    = SEG6_CMD_DUMPHMAC,
 409                 .start  = seg6_genl_dumphmac_start,
 410                 .dumpit = seg6_genl_dumphmac,
 411                 .done   = seg6_genl_dumphmac_done,
 412                 .policy = seg6_genl_policy,
 413                 .flags  = GENL_ADMIN_PERM,
 414         },
 415         {
 416                 .cmd    = SEG6_CMD_SET_TUNSRC,
 417                 .doit   = seg6_genl_set_tunsrc,
 418                 .policy = seg6_genl_policy,
 419                 .flags  = GENL_ADMIN_PERM,
 420         },
 421         {
 422                 .cmd    = SEG6_CMD_GET_TUNSRC,
 423                 .doit   = seg6_genl_get_tunsrc,
 424                 .policy = seg6_genl_policy,
 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         .netnsok        = true,
 435         .parallel_ops   = true,
 436         .ops            = seg6_genl_ops,
 437         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 438         .module         = THIS_MODULE,
 439 };
 440
 441 int __init seg6_init(void)
 442 {
 443         int err = -ENOMEM;
 444
 445         err = genl_register_family(&seg6_genl_family);
 446         if (err)
 447                 goto out;
 448
 449         err = register_pernet_subsys(&ip6_segments_ops);
 450         if (err)
 451                 goto out_unregister_genl;
 452
 453 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 454         err = seg6_iptunnel_init();
 455         if (err)
 456                 goto out_unregister_pernet;
 457
 458         err = seg6_local_init();
 459         if (err)
 460                 goto out_unregister_pernet;
 461 #endif
 462
 463 #ifdef CONFIG_IPV6_SEG6_HMAC
 464         err = seg6_hmac_init();
 465         if (err)
 466                 goto out_unregister_iptun;
 467 #endif
 468
 469         pr_info("Segment Routing with IPv6\n");
 470
 471 out:
 472         return err;
 473 #ifdef CONFIG_IPV6_SEG6_HMAC
 474 out_unregister_iptun:
 475 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 476         seg6_local_exit();
 477         seg6_iptunnel_exit();
 478 #endif
 479 #endif
 480 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 481 out_unregister_pernet:
 482         unregister_pernet_subsys(&ip6_segments_ops);
 483 #endif
 484 out_unregister_genl:
 485         genl_unregister_family(&seg6_genl_family);
 486         goto out;
 487 }
 488
 489 void seg6_exit(void)
 490 {
 491 #ifdef CONFIG_IPV6_SEG6_HMAC
 492         seg6_hmac_exit();
 493 #endif
 494 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 495         seg6_iptunnel_exit();
 496 #endif
 497         unregister_pernet_subsys(&ip6_segments_ops);
 498         genl_unregister_family(&seg6_genl_family);
 499 }