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 free_msg:
 230         nlmsg_free(msg);
 231         return -ENOMEM;
 232 }
 233
 234 #ifdef CONFIG_IPV6_SEG6_HMAC
 235
 236 static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
 237                                  struct sk_buff *msg)
 238 {
 239         if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
 240             nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
 241             nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
 242             nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
 243                 return -1;
 244
 245         return 0;
 246 }
 247
 248 static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
 249                                         u32 portid, u32 seq, u32 flags,
 250                                         struct sk_buff *skb, u8 cmd)
 251 {
 252         void *hdr;
 253
 254         hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
 255         if (!hdr)
 256                 return -ENOMEM;
 257
 258         if (__seg6_hmac_fill_info(hinfo, skb) < 0)
 259                 goto nla_put_failure;
 260
 261         genlmsg_end(skb, hdr);
 262         return 0;
 263
 264 nla_put_failure:
 265         genlmsg_cancel(skb, hdr);
 266         return -EMSGSIZE;
 267 }
 268
 269 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 270 {
 271         struct net *net = sock_net(cb->skb->sk);
 272         struct seg6_pernet_data *sdata;
 273         struct rhashtable_iter *iter;
 274
 275         sdata = seg6_pernet(net);
 276         iter = (struct rhashtable_iter *)cb->args[0];
 277
 278         if (!iter) {
 279                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 280                 if (!iter)
 281                         return -ENOMEM;
 282
 283                 cb->args[0] = (long)iter;
 284         }
 285
 286         rhashtable_walk_enter(&sdata->hmac_infos, iter);
 287
 288         return 0;
 289 }
 290
 291 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 292 {
 293         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 294
 295         rhashtable_walk_exit(iter);
 296
 297         kfree(iter);
 298
 299         return 0;
 300 }
 301
 302 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 303 {
 304         struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
 305         struct seg6_hmac_info *hinfo;
 306         int ret;
 307
 308         rhashtable_walk_start(iter);
 309
 310         for (;;) {
 311                 hinfo = rhashtable_walk_next(iter);
 312
 313                 if (IS_ERR(hinfo)) {
 314                         if (PTR_ERR(hinfo) == -EAGAIN)
 315                                 continue;
 316                         ret = PTR_ERR(hinfo);
 317                         goto done;
 318                 } else if (!hinfo) {
 319                         break;
 320                 }
 321
 322                 ret = __seg6_genl_dumphmac_element(hinfo,
 323                                                    NETLINK_CB(cb->skb).portid,
 324                                                    cb->nlh->nlmsg_seq,
 325                                                    NLM_F_MULTI,
 326                                                    skb, SEG6_CMD_DUMPHMAC);
 327                 if (ret)
 328                         goto done;
 329         }
 330
 331         ret = skb->len;
 332
 333 done:
 334         rhashtable_walk_stop(iter);
 335         return ret;
 336 }
 337
 338 #else
 339
 340 static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
 341 {
 342         return 0;
 343 }
 344
 345 static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
 346 {
 347         return 0;
 348 }
 349
 350 static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
 351 {
 352         return -ENOTSUPP;
 353 }
 354
 355 #endif
 356
 357 static int __net_init seg6_net_init(struct net *net)
 358 {
 359         struct seg6_pernet_data *sdata;
 360
 361         sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
 362         if (!sdata)
 363                 return -ENOMEM;
 364
 365         mutex_init(&sdata->lock);
 366
 367         sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
 368         if (!sdata->tun_src) {
 369                 kfree(sdata);
 370                 return -ENOMEM;
 371         }
 372
 373         net->ipv6.seg6_data = sdata;
 374
 375 #ifdef CONFIG_IPV6_SEG6_HMAC
 376         seg6_hmac_net_init(net);
 377 #endif
 378
 379         return 0;
 380 }
 381
 382 static void __net_exit seg6_net_exit(struct net *net)
 383 {
 384         struct seg6_pernet_data *sdata = seg6_pernet(net);
 385
 386 #ifdef CONFIG_IPV6_SEG6_HMAC
 387         seg6_hmac_net_exit(net);
 388 #endif
 389
 390         kfree(sdata->tun_src);
 391         kfree(sdata);
 392 }
 393
 394 static struct pernet_operations ip6_segments_ops = {
 395         .init = seg6_net_init,
 396         .exit = seg6_net_exit,
 397 };
 398
 399 static const struct genl_ops seg6_genl_ops[] = {
 400         {
 401                 .cmd    = SEG6_CMD_SETHMAC,
 402                 .doit   = seg6_genl_sethmac,
 403                 .policy = seg6_genl_policy,
 404                 .flags  = GENL_ADMIN_PERM,
 405         },
 406         {
 407                 .cmd    = SEG6_CMD_DUMPHMAC,
 408                 .start  = seg6_genl_dumphmac_start,
 409                 .dumpit = seg6_genl_dumphmac,
 410                 .done   = seg6_genl_dumphmac_done,
 411                 .policy = seg6_genl_policy,
 412                 .flags  = GENL_ADMIN_PERM,
 413         },
 414         {
 415                 .cmd    = SEG6_CMD_SET_TUNSRC,
 416                 .doit   = seg6_genl_set_tunsrc,
 417                 .policy = seg6_genl_policy,
 418                 .flags  = GENL_ADMIN_PERM,
 419         },
 420         {
 421                 .cmd    = SEG6_CMD_GET_TUNSRC,
 422                 .doit   = seg6_genl_get_tunsrc,
 423                 .policy = seg6_genl_policy,
 424                 .flags  = GENL_ADMIN_PERM,
 425         },
 426 };
 427
 428 static struct genl_family seg6_genl_family __ro_after_init = {
 429         .hdrsize        = 0,
 430         .name           = SEG6_GENL_NAME,
 431         .version        = SEG6_GENL_VERSION,
 432         .maxattr        = SEG6_ATTR_MAX,
 433         .netnsok        = true,
 434         .parallel_ops   = true,
 435         .ops            = seg6_genl_ops,
 436         .n_ops          = ARRAY_SIZE(seg6_genl_ops),
 437         .module         = THIS_MODULE,
 438 };
 439
 440 int __init seg6_init(void)
 441 {
 442         int err = -ENOMEM;
 443
 444         err = genl_register_family(&seg6_genl_family);
 445         if (err)
 446                 goto out;
 447
 448         err = register_pernet_subsys(&ip6_segments_ops);
 449         if (err)
 450                 goto out_unregister_genl;
 451
 452 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 453         err = seg6_iptunnel_init();
 454         if (err)
 455                 goto out_unregister_pernet;
 456
 457         err = seg6_local_init();
 458         if (err)
 459                 goto out_unregister_pernet;
 460 #endif
 461
 462 #ifdef CONFIG_IPV6_SEG6_HMAC
 463         err = seg6_hmac_init();
 464         if (err)
 465                 goto out_unregister_iptun;
 466 #endif
 467
 468         pr_info("Segment Routing with IPv6\n");
 469
 470 out:
 471         return err;
 472 #ifdef CONFIG_IPV6_SEG6_HMAC
 473 out_unregister_iptun:
 474 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 475         seg6_local_exit();
 476         seg6_iptunnel_exit();
 477 #endif
 478 #endif
 479 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 480 out_unregister_pernet:
 481         unregister_pernet_subsys(&ip6_segments_ops);
 482 #endif
 483 out_unregister_genl:
 484         genl_unregister_family(&seg6_genl_family);
 485         goto out;
 486 }
 487
 488 void seg6_exit(void)
 489 {
 490 #ifdef CONFIG_IPV6_SEG6_HMAC
 491         seg6_hmac_exit();
 492 #endif
 493 #ifdef CONFIG_IPV6_SEG6_LWTUNNEL
 494         seg6_iptunnel_exit();
 495 #endif
 496         unregister_pernet_subsys(&ip6_segments_ops);
 497         genl_unregister_family(&seg6_genl_family);
 498 }