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 (hinfo) {
 133                 err = seg6_hmac_info_del(net, hmackeyid);
 134                 if (err)
 135                         goto out_unlock;
 136         }
 137
 138         secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
 139
 140         hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
 141         if (!hinfo) {
 142                 err = -ENOMEM;
 143                 goto out_unlock;
 144         }
 145
 146         memcpy(hinfo->secret, secret, slen);
 147         hinfo->slen = slen;
 148         hinfo->alg_id = algid;
 149         hinfo->hmackeyid = hmackeyid;
 150
 151         err = seg6_hmac_info_add(net, hmackeyid, hinfo);
 152         if (err)
 153                 kfree(hinfo);
 154
 155 out_unlock:
 156         mutex_unlock(&sdata->lock);
 157         return err;
 158 }
 159
 160 #else
 161
 162 static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 163 {
 164         return -ENOTSUPP;
 165 }
 166
 167 #endif
 168
 169 static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
 170 {
 171         struct net *net = genl_info_net(info);
 172         struct in6_addr *val, *t_old, *t_new;
 173         struct seg6_pernet_data *sdata;
 174
 175         sdata = seg6_pernet(net);
 176
 177         if (!info->attrs[SEG6_ATTR_DST])
 178                 return -EINVAL;
 179
 180         val = nla_data(info->attrs[SEG6_ATTR_DST]);
 181         t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
 182         if (!t_new)
 183                 return -ENOMEM;
 184
 185         mutex_lock(&sdata->lock);
 186
 187         t_old = sdata->tun_src;
 188         rcu_assign_pointer(sdata->tun_src, t_new);
 189
 190         mutex_unlock(&sdata->lock);
 191
 192         synchronize_net();
 193         kfree(t_old);
 194
 195         return 0;
 196 }
 197
 198 static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
 199 {
 200         struct net *net = genl_info_net(info);
 201         struct in6_addr *tun_src;
 202         struct sk_buff *msg;
 203         void *hdr;
 204
 205         msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 206         if (!msg)
 207                 return -ENOMEM;
 208
 209         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
 210                           &seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
 211         if (!hdr)
 212                 goto free_msg;
 213
 214         rcu_read_lock();
 215         tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
 216
 217         if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
 218                 goto nla_put_failure;
 219
 220         rcu_read_unlock();
 221
 222         genlmsg_end(msg, hdr);
 223         genlmsg_reply(msg, info);
 224
 225         return 0;
 226
 227 nla_put_failure:
 228         rcu_read_unlock();
 229         genlmsg_cancel(msg, hdr);
 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 net *net = sock_net(skb->sk);
 307         struct seg6_pernet_data *sdata;
 308         struct seg6_hmac_info *hinfo;
 309         int ret;
 310
 311         sdata = seg6_pernet(net);
 312
 313         ret = rhashtable_walk_start(iter);
 314         if (ret && ret != -EAGAIN)
 315                 goto done;
 316
 317         for (;;) {
 318                 hinfo = rhashtable_walk_next(iter);
 319
 320                 if (IS_ERR(hinfo)) {
 321                         if (PTR_ERR(hinfo) == -EAGAIN)
 322                                 continue;
 323                         ret = PTR_ERR(hinfo);
 324                         goto done;
 325                 } else if (!hinfo) {
 326                         break;
 327                 }
 328
 329                 ret = __seg6_genl_dumphmac_element(hinfo,
 330                                                    NETLINK_CB(cb->skb).portid,
 331                                                    cb->nlh->nlmsg_seq,
 332                                                    NLM_F_MULTI,
 333                                                    skb, SEG6_CMD_DUMPHMAC);
 334                 if (ret)
 335                         goto done;
 336         }
 337
 338         ret = skb->len;
 339
 340 done:
 341         rhashtable_walk_stop(iter);
 342         return ret;
 343 }
 344
 345 #else
 346
 347 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 348 {
 349         return 0;
 350 }
 351
 352 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 353 {
 354         return 0;
 355 }
 356
 357 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 358 {
 359         return -ENOTSUPP;
 360 }
 361
 362 #endif
 363
 364 static int __net_init seg6_net_init(struct net *net)
 365 {
 366         struct seg6_pernet_data *sdata;
 367
 368         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 369         if (!sdata)
 370                 return -ENOMEM;
 371
 372         mutex_init(&sdata->lock);
 373
 374         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 375         if (!sdata->tun_src) {
 376                 kfree(sdata);
 377                 return -ENOMEM;
 378         }
 379
 380         net->ipv6.seg6_data = sdata;
 381
 382 #ifdef CONFIG_IPV6_SEG6_HMAC
 383         seg6_hmac_net_init(net);
 384 #endif
 385
 386         return 0;
 387 }
 388
 389 static void __net_exit seg6_net_exit(struct net *net)
 390 {
 391         struct seg6_pernet_data *sdata = seg6_pernet(net);
 392
 393 #ifdef CONFIG_IPV6_SEG6_HMAC
 394         seg6_hmac_net_exit(net);
 395 #endif
 396
 397         kfree(sdata->tun_src);
 398         kfree(sdata);
 399 }
 400
 401 static struct pernet_operations ip6_segments_ops = {
 402         .init = seg6_net_init,
 403         .exit = seg6_net_exit,
 404 };
 405
 406 static const struct genl_ops seg6_genl_ops[] = {
 407         {
 408                 .cmd    = SEG6_CMD_SETHMAC,
 409                 .doit   = seg6_genl_sethmac,
 410                 .policy = seg6_genl_policy,
 411                 .flags  = GENL_ADMIN_PERM,
 412         },
 413         {
 414                 .cmd    = SEG6_CMD_DUMPHMAC,
 415                 .start  = seg6_genl_dumphmac_start,
 416                 .dumpit = seg6_genl_dumphmac,
 417                 .done   = seg6_genl_dumphmac_done,
 418                 .policy = seg6_genl_policy,
 419                 .flags  = GENL_ADMIN_PERM,
 420         },
 421         {
 422                 .cmd    = SEG6_CMD_SET_TUNSRC,
 423                 .doit   = seg6_genl_set_tunsrc,
 424                 .policy = seg6_genl_policy,
 425                 .flags  = GENL_ADMIN_PERM,
 426         },
 427         {
 428                 .cmd    = SEG6_CMD_GET_TUNSRC,
 429                 .doit   = seg6_genl_get_tunsrc,
 430                 .policy = seg6_genl_policy,
 431                 .flags  = GENL_ADMIN_PERM,
 432         },
 433 };
 434
 435 static struct genl_family seg6_genl_family __ro_after_init = {
 436         .hdrsize        = 0,
 437         .name           = SEG6_GENL_NAME,
 438         .version        = SEG6_GENL_VERSION,
 439         .maxattr        = SEG6_ATTR_MAX,
 440         .netnsok        = true,
 441         .parallel_ops   = true,
 442         .ops            = seg6_genl_ops,
 443         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 444         .module         = THIS_MODULE,
 445 };
 446
 447 int __init seg6_init(void)
 448 {
 449         int err = -ENOMEM;
 450
 451         err = genl_register_family(&seg6_genl_family);
 452         if (err)
 453                 goto out;
 454
 455         err = register_pernet_subsys(&ip6_segments_ops);
 456         if (err)
 457                 goto out_unregister_genl;
 458
 459 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 460         err = seg6_iptunnel_init();
 461         if (err)
 462                 goto out_unregister_pernet;
 463 #endif
 464
 465 #ifdef CONFIG_IPV6_SEG6_HMAC
 466         err = seg6_hmac_init();
 467         if (err)
 468                 goto out_unregister_iptun;
 469 #endif
 470
 471         pr_info("Segment Routing with IPv6\n");
 472
 473 out:
 474         return err;
 475 #ifdef CONFIG_IPV6_SEG6_HMAC
 476 out_unregister_iptun:
 477 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 478         seg6_iptunnel_exit();
 479 #endif
 480 #endif
 481 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 482 out_unregister_pernet:
 483         unregister_pernet_subsys(&ip6_segments_ops);
 484 #endif
 485 out_unregister_genl:
 486         genl_unregister_family(&seg6_genl_family);
 487         goto out;
 488 }
 489
 490 void seg6_exit(void)
 491 {
 492 #ifdef CONFIG_IPV6_SEG6_HMAC
 493         seg6_hmac_exit();
 494 #endif
 495 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 496         seg6_iptunnel_exit();
 497 #endif
 498         unregister_pernet_subsys(&ip6_segments_ops);
 499         genl_unregister_family(&seg6_genl_family);
 500 }