net/l2tp/l2tp_netlink.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* L2TP netlink layer, for management
   3  *
   4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
   5  *
   6  * Partly based on the IrDA nelink implementation
   7  * (see net/irda/irnetlink.c) which is:
   8  * Copyright (c) 2007 Samuel Ortiz <samuel@sortiz.org>
   9  * which is in turn partly based on the wireless netlink code:
  10  * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <net/sock.h>
  16 #include <net/genetlink.h>
  17 #include <net/udp.h>
  18 #include <linux/in.h>
  19 #include <linux/udp.h>
  20 #include <linux/socket.h>
  21 #include <linux/module.h>
  22 #include <linux/list.h>
  23 #include <net/net_namespace.h>
  24
  25 #include <linux/l2tp.h>
  26
  27 #include "l2tp_core.h"
  28
  29 static struct genl_family l2tp_nl_family;
  30
  31 static const struct genl_multicast_group l2tp_multicast_group[] = {
  32         {
  33                 .name = L2TP_GENL_MCGROUP,
  34         },
  35 };
  36
  37 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq,
  38                                int flags, struct l2tp_tunnel *tunnel, u8 cmd);
  39 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
  40                                 int flags, struct l2tp_session *session,
  41                                 u8 cmd);
  42
  43 /* Accessed under genl lock */
  44 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
  45
  46 static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
  47 {
  48         u32 tunnel_id;
  49         u32 session_id;
  50         char *ifname;
  51         struct l2tp_tunnel *tunnel;
  52         struct l2tp_session *session = NULL;
  53         struct net *net = genl_info_net(info);
  54
  55         if (info->attrs[L2TP_ATTR_IFNAME]) {
  56                 ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
  57                 session = l2tp_session_get_by_ifname(net, ifname);
  58         } else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
  59                    (info->attrs[L2TP_ATTR_CONN_ID])) {
  60                 tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
  61                 session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
  62                 tunnel = l2tp_tunnel_get(net, tunnel_id);
  63                 if (tunnel) {
  64                         session = l2tp_tunnel_get_session(tunnel, session_id);
  65                         l2tp_tunnel_dec_refcount(tunnel);
  66                 }
  67         }
  68
  69         return session;
  70 }
  71
  72 static int l2tp_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
  73 {
  74         struct sk_buff *msg;
  75         void *hdr;
  76         int ret = -ENOBUFS;
  77
  78         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
  79         if (!msg) {
  80                 ret = -ENOMEM;
  81                 goto out;
  82         }
  83
  84         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
  85                           &l2tp_nl_family, 0, L2TP_CMD_NOOP);
  86         if (!hdr) {
  87                 ret = -EMSGSIZE;
  88                 goto err_out;
  89         }
  90
  91         genlmsg_end(msg, hdr);
  92
  93         return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
  94
  95 err_out:
  96         nlmsg_free(msg);
  97
  98 out:
  99         return ret;
 100 }
 101
 102 static int l2tp_tunnel_notify(struct genl_family *family,
 103                               struct genl_info *info,
 104                               struct l2tp_tunnel *tunnel,
 105                               u8 cmd)
 106 {
 107         struct sk_buff *msg;
 108         int ret;
 109
 110         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 111         if (!msg)
 112                 return -ENOMEM;
 113
 114         ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
 115                                   NLM_F_ACK, tunnel, cmd);
 116
 117         if (ret >= 0) {
 118                 ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
 119                 /* We don't care if no one is listening */
 120                 if (ret == -ESRCH)
 121                         ret = 0;
 122                 return ret;
 123         }
 124
 125         nlmsg_free(msg);
 126
 127         return ret;
 128 }
 129
 130 static int l2tp_session_notify(struct genl_family *family,
 131                                struct genl_info *info,
 132                                struct l2tp_session *session,
 133                                u8 cmd)
 134 {
 135         struct sk_buff *msg;
 136         int ret;
 137
 138         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 139         if (!msg)
 140                 return -ENOMEM;
 141
 142         ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
 143                                    NLM_F_ACK, session, cmd);
 144
 145         if (ret >= 0) {
 146                 ret = genlmsg_multicast_allns(family, msg, 0, 0, GFP_ATOMIC);
 147                 /* We don't care if no one is listening */
 148                 if (ret == -ESRCH)
 149                         ret = 0;
 150                 return ret;
 151         }
 152
 153         nlmsg_free(msg);
 154
 155         return ret;
 156 }
 157
 158 static int l2tp_nl_cmd_tunnel_create_get_addr(struct nlattr **attrs, struct l2tp_tunnel_cfg *cfg)
 159 {
 160         if (attrs[L2TP_ATTR_UDP_SPORT])
 161                 cfg->local_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_SPORT]);
 162         if (attrs[L2TP_ATTR_UDP_DPORT])
 163                 cfg->peer_udp_port = nla_get_u16(attrs[L2TP_ATTR_UDP_DPORT]);
 164         cfg->use_udp_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_CSUM]);
 165
 166         /* Must have either AF_INET or AF_INET6 address for source and destination */
 167 #if IS_ENABLED(CONFIG_IPV6)
 168         if (attrs[L2TP_ATTR_IP6_SADDR] && attrs[L2TP_ATTR_IP6_DADDR]) {
 169                 cfg->local_ip6 = nla_data(attrs[L2TP_ATTR_IP6_SADDR]);
 170                 cfg->peer_ip6 = nla_data(attrs[L2TP_ATTR_IP6_DADDR]);
 171                 cfg->udp6_zero_tx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_TX]);
 172                 cfg->udp6_zero_rx_checksums = nla_get_flag(attrs[L2TP_ATTR_UDP_ZERO_CSUM6_RX]);
 173                 return 0;
 174         }
 175 #endif
 176         if (attrs[L2TP_ATTR_IP_SADDR] && attrs[L2TP_ATTR_IP_DADDR]) {
 177                 cfg->local_ip.s_addr = nla_get_in_addr(attrs[L2TP_ATTR_IP_SADDR]);
 178                 cfg->peer_ip.s_addr = nla_get_in_addr(attrs[L2TP_ATTR_IP_DADDR]);
 179                 return 0;
 180         }
 181         return -EINVAL;
 182 }
 183
 184 static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info)
 185 {
 186         u32 tunnel_id;
 187         u32 peer_tunnel_id;
 188         int proto_version;
 189         int fd = -1;
 190         int ret = 0;
 191         struct l2tp_tunnel_cfg cfg = { 0, };
 192         struct l2tp_tunnel *tunnel;
 193         struct net *net = genl_info_net(info);
 194         struct nlattr **attrs = info->attrs;
 195
 196         if (!attrs[L2TP_ATTR_CONN_ID]) {
 197                 ret = -EINVAL;
 198                 goto out;
 199         }
 200         tunnel_id = nla_get_u32(attrs[L2TP_ATTR_CONN_ID]);
 201
 202         if (!attrs[L2TP_ATTR_PEER_CONN_ID]) {
 203                 ret = -EINVAL;
 204                 goto out;
 205         }
 206         peer_tunnel_id = nla_get_u32(attrs[L2TP_ATTR_PEER_CONN_ID]);
 207
 208         if (!attrs[L2TP_ATTR_PROTO_VERSION]) {
 209                 ret = -EINVAL;
 210                 goto out;
 211         }
 212         proto_version = nla_get_u8(attrs[L2TP_ATTR_PROTO_VERSION]);
 213
 214         if (!attrs[L2TP_ATTR_ENCAP_TYPE]) {
 215                 ret = -EINVAL;
 216                 goto out;
 217         }
 218         cfg.encap = nla_get_u16(attrs[L2TP_ATTR_ENCAP_TYPE]);
 219
 220         /* Managed tunnels take the tunnel socket from userspace.
 221          * Unmanaged tunnels must call out the source and destination addresses
 222          * for the kernel to create the tunnel socket itself.
 223          */
 224         if (attrs[L2TP_ATTR_FD]) {
 225                 fd = nla_get_u32(attrs[L2TP_ATTR_FD]);
 226         } else {
 227                 ret = l2tp_nl_cmd_tunnel_create_get_addr(attrs, &cfg);
 228                 if (ret < 0)
 229                         goto out;
 230         }
 231
 232         ret = -EINVAL;
 233         switch (cfg.encap) {
 234         case L2TP_ENCAPTYPE_UDP:
 235         case L2TP_ENCAPTYPE_IP:
 236                 ret = l2tp_tunnel_create(fd, proto_version, tunnel_id,
 237                                          peer_tunnel_id, &cfg, &tunnel);
 238                 break;
 239         }
 240
 241         if (ret < 0)
 242                 goto out;
 243
 244         l2tp_tunnel_inc_refcount(tunnel);
 245         ret = l2tp_tunnel_register(tunnel, net, &cfg);
 246         if (ret < 0) {
 247                 kfree(tunnel);
 248                 goto out;
 249         }
 250         ret = l2tp_tunnel_notify(&l2tp_nl_family, info, tunnel,
 251                                  L2TP_CMD_TUNNEL_CREATE);
 252         l2tp_tunnel_dec_refcount(tunnel);
 253
 254 out:
 255         return ret;
 256 }
 257
 258 static int l2tp_nl_cmd_tunnel_delete(struct sk_buff *skb, struct genl_info *info)
 259 {
 260         struct l2tp_tunnel *tunnel;
 261         u32 tunnel_id;
 262         int ret = 0;
 263         struct net *net = genl_info_net(info);
 264
 265         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 266                 ret = -EINVAL;
 267                 goto out;
 268         }
 269         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 270
 271         tunnel = l2tp_tunnel_get(net, tunnel_id);
 272         if (!tunnel) {
 273                 ret = -ENODEV;
 274                 goto out;
 275         }
 276
 277         l2tp_tunnel_notify(&l2tp_nl_family, info,
 278                            tunnel, L2TP_CMD_TUNNEL_DELETE);
 279
 280         l2tp_tunnel_delete(tunnel);
 281
 282         l2tp_tunnel_dec_refcount(tunnel);
 283
 284 out:
 285         return ret;
 286 }
 287
 288 static int l2tp_nl_cmd_tunnel_modify(struct sk_buff *skb, struct genl_info *info)
 289 {
 290         struct l2tp_tunnel *tunnel;
 291         u32 tunnel_id;
 292         int ret = 0;
 293         struct net *net = genl_info_net(info);
 294
 295         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 296                 ret = -EINVAL;
 297                 goto out;
 298         }
 299         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 300
 301         tunnel = l2tp_tunnel_get(net, tunnel_id);
 302         if (!tunnel) {
 303                 ret = -ENODEV;
 304                 goto out;
 305         }
 306
 307         ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
 308                                  tunnel, L2TP_CMD_TUNNEL_MODIFY);
 309
 310         l2tp_tunnel_dec_refcount(tunnel);
 311
 312 out:
 313         return ret;
 314 }
 315
 316 #if IS_ENABLED(CONFIG_IPV6)
 317 static int l2tp_nl_tunnel_send_addr6(struct sk_buff *skb, struct sock *sk,
 318                                      enum l2tp_encap_type encap)
 319 {
 320         struct inet_sock *inet = inet_sk(sk);
 321         struct ipv6_pinfo *np = inet6_sk(sk);
 322
 323         switch (encap) {
 324         case L2TP_ENCAPTYPE_UDP:
 325                 if (udp_get_no_check6_tx(sk) &&
 326                     nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_TX))
 327                         return -1;
 328                 if (udp_get_no_check6_rx(sk) &&
 329                     nla_put_flag(skb, L2TP_ATTR_UDP_ZERO_CSUM6_RX))
 330                         return -1;
 331                 if (nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
 332                     nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
 333                         return -1;
 334                 fallthrough;
 335         case L2TP_ENCAPTYPE_IP:
 336                 if (nla_put_in6_addr(skb, L2TP_ATTR_IP6_SADDR, &np->saddr) ||
 337                     nla_put_in6_addr(skb, L2TP_ATTR_IP6_DADDR, &sk->sk_v6_daddr))
 338                         return -1;
 339                 break;
 340         }
 341         return 0;
 342 }
 343 #endif
 344
 345 static int l2tp_nl_tunnel_send_addr4(struct sk_buff *skb, struct sock *sk,
 346                                      enum l2tp_encap_type encap)
 347 {
 348         struct inet_sock *inet = inet_sk(sk);
 349
 350         switch (encap) {
 351         case L2TP_ENCAPTYPE_UDP:
 352                 if (nla_put_u8(skb, L2TP_ATTR_UDP_CSUM, !sk->sk_no_check_tx) ||
 353                     nla_put_u16(skb, L2TP_ATTR_UDP_SPORT, ntohs(inet->inet_sport)) ||
 354                     nla_put_u16(skb, L2TP_ATTR_UDP_DPORT, ntohs(inet->inet_dport)))
 355                         return -1;
 356                 fallthrough;
 357         case L2TP_ENCAPTYPE_IP:
 358                 if (nla_put_in_addr(skb, L2TP_ATTR_IP_SADDR, inet->inet_saddr) ||
 359                     nla_put_in_addr(skb, L2TP_ATTR_IP_DADDR, inet->inet_daddr))
 360                         return -1;
 361                 break;
 362         }
 363
 364         return 0;
 365 }
 366
 367 /* Append attributes for the tunnel address, handling the different attribute types
 368  * used for different tunnel encapsulation and AF_INET v.s. AF_INET6.
 369  */
 370 static int l2tp_nl_tunnel_send_addr(struct sk_buff *skb, struct l2tp_tunnel *tunnel)
 371 {
 372         struct sock *sk = tunnel->sock;
 373
 374         if (!sk)
 375                 return 0;
 376
 377 #if IS_ENABLED(CONFIG_IPV6)
 378         if (sk->sk_family == AF_INET6)
 379                 return l2tp_nl_tunnel_send_addr6(skb, sk, tunnel->encap);
 380 #endif
 381         return l2tp_nl_tunnel_send_addr4(skb, sk, tunnel->encap);
 382 }
 383
 384 static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
 385                                struct l2tp_tunnel *tunnel, u8 cmd)
 386 {
 387         void *hdr;
 388         struct nlattr *nest;
 389
 390         hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
 391         if (!hdr)
 392                 return -EMSGSIZE;
 393
 394         if (nla_put_u8(skb, L2TP_ATTR_PROTO_VERSION, tunnel->version) ||
 395             nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
 396             nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
 397             nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
 398             nla_put_u16(skb, L2TP_ATTR_ENCAP_TYPE, tunnel->encap))
 399                 goto nla_put_failure;
 400
 401         nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
 402         if (!nest)
 403                 goto nla_put_failure;
 404
 405         if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
 406                               atomic_long_read(&tunnel->stats.tx_packets),
 407                               L2TP_ATTR_STATS_PAD) ||
 408             nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
 409                               atomic_long_read(&tunnel->stats.tx_bytes),
 410                               L2TP_ATTR_STATS_PAD) ||
 411             nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
 412                               atomic_long_read(&tunnel->stats.tx_errors),
 413                               L2TP_ATTR_STATS_PAD) ||
 414             nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
 415                               atomic_long_read(&tunnel->stats.rx_packets),
 416                               L2TP_ATTR_STATS_PAD) ||
 417             nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
 418                               atomic_long_read(&tunnel->stats.rx_bytes),
 419                               L2TP_ATTR_STATS_PAD) ||
 420             nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
 421                               atomic_long_read(&tunnel->stats.rx_seq_discards),
 422                               L2TP_ATTR_STATS_PAD) ||
 423             nla_put_u64_64bit(skb, L2TP_ATTR_RX_COOKIE_DISCARDS,
 424                               atomic_long_read(&tunnel->stats.rx_cookie_discards),
 425                               L2TP_ATTR_STATS_PAD) ||
 426             nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
 427                               atomic_long_read(&tunnel->stats.rx_oos_packets),
 428                               L2TP_ATTR_STATS_PAD) ||
 429             nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
 430                               atomic_long_read(&tunnel->stats.rx_errors),
 431                               L2TP_ATTR_STATS_PAD) ||
 432             nla_put_u64_64bit(skb, L2TP_ATTR_RX_INVALID,
 433                               atomic_long_read(&tunnel->stats.rx_invalid),
 434                               L2TP_ATTR_STATS_PAD))
 435                 goto nla_put_failure;
 436         nla_nest_end(skb, nest);
 437
 438         if (l2tp_nl_tunnel_send_addr(skb, tunnel))
 439                 goto nla_put_failure;
 440
 441         genlmsg_end(skb, hdr);
 442         return 0;
 443
 444 nla_put_failure:
 445         genlmsg_cancel(skb, hdr);
 446         return -1;
 447 }
 448
 449 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
 450 {
 451         struct l2tp_tunnel *tunnel;
 452         struct sk_buff *msg;
 453         u32 tunnel_id;
 454         int ret = -ENOBUFS;
 455         struct net *net = genl_info_net(info);
 456
 457         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 458                 ret = -EINVAL;
 459                 goto err;
 460         }
 461
 462         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 463
 464         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 465         if (!msg) {
 466                 ret = -ENOMEM;
 467                 goto err;
 468         }
 469
 470         tunnel = l2tp_tunnel_get(net, tunnel_id);
 471         if (!tunnel) {
 472                 ret = -ENODEV;
 473                 goto err_nlmsg;
 474         }
 475
 476         ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
 477                                   NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
 478         if (ret < 0)
 479                 goto err_nlmsg_tunnel;
 480
 481         l2tp_tunnel_dec_refcount(tunnel);
 482
 483         return genlmsg_unicast(net, msg, info->snd_portid);
 484
 485 err_nlmsg_tunnel:
 486         l2tp_tunnel_dec_refcount(tunnel);
 487 err_nlmsg:
 488         nlmsg_free(msg);
 489 err:
 490         return ret;
 491 }
 492
 493 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
 494 {
 495         int ti = cb->args[0];
 496         struct l2tp_tunnel *tunnel;
 497         struct net *net = sock_net(skb->sk);
 498
 499         for (;;) {
 500                 tunnel = l2tp_tunnel_get_nth(net, ti);
 501                 if (!tunnel)
 502                         goto out;
 503
 504                 if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
 505                                         cb->nlh->nlmsg_seq, NLM_F_MULTI,
 506                                         tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
 507                         l2tp_tunnel_dec_refcount(tunnel);
 508                         goto out;
 509                 }
 510                 l2tp_tunnel_dec_refcount(tunnel);
 511
 512                 ti++;
 513         }
 514
 515 out:
 516         cb->args[0] = ti;
 517
 518         return skb->len;
 519 }
 520
 521 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
 522 {
 523         u32 tunnel_id = 0;
 524         u32 session_id;
 525         u32 peer_session_id;
 526         int ret = 0;
 527         struct l2tp_tunnel *tunnel;
 528         struct l2tp_session *session;
 529         struct l2tp_session_cfg cfg = { 0, };
 530         struct net *net = genl_info_net(info);
 531
 532         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 533                 ret = -EINVAL;
 534                 goto out;
 535         }
 536
 537         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 538         tunnel = l2tp_tunnel_get(net, tunnel_id);
 539         if (!tunnel) {
 540                 ret = -ENODEV;
 541                 goto out;
 542         }
 543
 544         if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
 545                 ret = -EINVAL;
 546                 goto out_tunnel;
 547         }
 548         session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
 549
 550         if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
 551                 ret = -EINVAL;
 552                 goto out_tunnel;
 553         }
 554         peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
 555
 556         if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
 557                 ret = -EINVAL;
 558                 goto out_tunnel;
 559         }
 560         cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
 561         if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
 562                 ret = -EINVAL;
 563                 goto out_tunnel;
 564         }
 565
 566         /* L2TPv2 only accepts PPP pseudo-wires */
 567         if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
 568                 ret = -EPROTONOSUPPORT;
 569                 goto out_tunnel;
 570         }
 571
 572         if (tunnel->version > 2) {
 573                 if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
 574                         cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
 575                         if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
 576                             cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
 577                                 ret = -EINVAL;
 578                                 goto out_tunnel;
 579                         }
 580                 } else {
 581                         cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
 582                 }
 583
 584                 if (info->attrs[L2TP_ATTR_COOKIE]) {
 585                         u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
 586
 587                         if (len > 8) {
 588                                 ret = -EINVAL;
 589                                 goto out_tunnel;
 590                         }
 591                         cfg.cookie_len = len;
 592                         memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
 593                 }
 594                 if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
 595                         u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
 596
 597                         if (len > 8) {
 598                                 ret = -EINVAL;
 599                                 goto out_tunnel;
 600                         }
 601                         cfg.peer_cookie_len = len;
 602                         memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
 603                 }
 604                 if (info->attrs[L2TP_ATTR_IFNAME])
 605                         cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
 606         }
 607
 608         if (info->attrs[L2TP_ATTR_RECV_SEQ])
 609                 cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 610
 611         if (info->attrs[L2TP_ATTR_SEND_SEQ])
 612                 cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
 613
 614         if (info->attrs[L2TP_ATTR_LNS_MODE])
 615                 cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
 616
 617         if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
 618                 cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
 619
 620 #ifdef CONFIG_MODULES
 621         if (!l2tp_nl_cmd_ops[cfg.pw_type]) {
 622                 genl_unlock();
 623                 request_module("net-l2tp-type-%u", cfg.pw_type);
 624                 genl_lock();
 625         }
 626 #endif
 627         if (!l2tp_nl_cmd_ops[cfg.pw_type] || !l2tp_nl_cmd_ops[cfg.pw_type]->session_create) {
 628                 ret = -EPROTONOSUPPORT;
 629                 goto out_tunnel;
 630         }
 631
 632         ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
 633                                                            session_id,
 634                                                            peer_session_id,
 635                                                            &cfg);
 636
 637         if (ret >= 0) {
 638                 session = l2tp_tunnel_get_session(tunnel, session_id);
 639                 if (session) {
 640                         ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 641                                                   L2TP_CMD_SESSION_CREATE);
 642                         l2tp_session_dec_refcount(session);
 643                 }
 644         }
 645
 646 out_tunnel:
 647         l2tp_tunnel_dec_refcount(tunnel);
 648 out:
 649         return ret;
 650 }
 651
 652 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
 653 {
 654         int ret = 0;
 655         struct l2tp_session *session;
 656         u16 pw_type;
 657
 658         session = l2tp_nl_session_get(info);
 659         if (!session) {
 660                 ret = -ENODEV;
 661                 goto out;
 662         }
 663
 664         l2tp_session_notify(&l2tp_nl_family, info,
 665                             session, L2TP_CMD_SESSION_DELETE);
 666
 667         pw_type = session->pwtype;
 668         if (pw_type < __L2TP_PWTYPE_MAX)
 669                 if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
 670                         l2tp_nl_cmd_ops[pw_type]->session_delete(session);
 671
 672         l2tp_session_dec_refcount(session);
 673
 674 out:
 675         return ret;
 676 }
 677
 678 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
 679 {
 680         int ret = 0;
 681         struct l2tp_session *session;
 682
 683         session = l2tp_nl_session_get(info);
 684         if (!session) {
 685                 ret = -ENODEV;
 686                 goto out;
 687         }
 688
 689         if (info->attrs[L2TP_ATTR_RECV_SEQ])
 690                 session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 691
 692         if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
 693                 session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
 694                 l2tp_session_set_header_len(session, session->tunnel->version);
 695         }
 696
 697         if (info->attrs[L2TP_ATTR_LNS_MODE])
 698                 session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
 699
 700         if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
 701                 session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
 702
 703         ret = l2tp_session_notify(&l2tp_nl_family, info,
 704                                   session, L2TP_CMD_SESSION_MODIFY);
 705
 706         l2tp_session_dec_refcount(session);
 707
 708 out:
 709         return ret;
 710 }
 711
 712 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
 713                                 struct l2tp_session *session, u8 cmd)
 714 {
 715         void *hdr;
 716         struct nlattr *nest;
 717         struct l2tp_tunnel *tunnel = session->tunnel;
 718
 719         hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
 720         if (!hdr)
 721                 return -EMSGSIZE;
 722
 723         if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
 724             nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
 725             nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
 726             nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID, session->peer_session_id) ||
 727             nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
 728             nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
 729                 goto nla_put_failure;
 730
 731         if ((session->ifname[0] &&
 732              nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
 733             (session->cookie_len &&
 734              nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len, session->cookie)) ||
 735             (session->peer_cookie_len &&
 736              nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len, session->peer_cookie)) ||
 737             nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
 738             nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
 739             nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
 740             (l2tp_tunnel_uses_xfrm(tunnel) &&
 741              nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
 742             (session->reorder_timeout &&
 743              nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
 744                            session->reorder_timeout, L2TP_ATTR_PAD)))
 745                 goto nla_put_failure;
 746
 747         nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
 748         if (!nest)
 749                 goto nla_put_failure;
 750
 751         if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
 752                               atomic_long_read(&session->stats.tx_packets),
 753                               L2TP_ATTR_STATS_PAD) ||
 754             nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
 755                               atomic_long_read(&session->stats.tx_bytes),
 756                               L2TP_ATTR_STATS_PAD) ||
 757             nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
 758                               atomic_long_read(&session->stats.tx_errors),
 759                               L2TP_ATTR_STATS_PAD) ||
 760             nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
 761                               atomic_long_read(&session->stats.rx_packets),
 762                               L2TP_ATTR_STATS_PAD) ||
 763             nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
 764                               atomic_long_read(&session->stats.rx_bytes),
 765                               L2TP_ATTR_STATS_PAD) ||
 766             nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
 767                               atomic_long_read(&session->stats.rx_seq_discards),
 768                               L2TP_ATTR_STATS_PAD) ||
 769             nla_put_u64_64bit(skb, L2TP_ATTR_RX_COOKIE_DISCARDS,
 770                               atomic_long_read(&session->stats.rx_cookie_discards),
 771                               L2TP_ATTR_STATS_PAD) ||
 772             nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
 773                               atomic_long_read(&session->stats.rx_oos_packets),
 774                               L2TP_ATTR_STATS_PAD) ||
 775             nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
 776                               atomic_long_read(&session->stats.rx_errors),
 777                               L2TP_ATTR_STATS_PAD) ||
 778             nla_put_u64_64bit(skb, L2TP_ATTR_RX_INVALID,
 779                               atomic_long_read(&session->stats.rx_invalid),
 780                               L2TP_ATTR_STATS_PAD))
 781                 goto nla_put_failure;
 782         nla_nest_end(skb, nest);
 783
 784         genlmsg_end(skb, hdr);
 785         return 0;
 786
 787  nla_put_failure:
 788         genlmsg_cancel(skb, hdr);
 789         return -1;
 790 }
 791
 792 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
 793 {
 794         struct l2tp_session *session;
 795         struct sk_buff *msg;
 796         int ret;
 797
 798         session = l2tp_nl_session_get(info);
 799         if (!session) {
 800                 ret = -ENODEV;
 801                 goto err;
 802         }
 803
 804         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 805         if (!msg) {
 806                 ret = -ENOMEM;
 807                 goto err_ref;
 808         }
 809
 810         ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
 811                                    0, session, L2TP_CMD_SESSION_GET);
 812         if (ret < 0)
 813                 goto err_ref_msg;
 814
 815         ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
 816
 817         l2tp_session_dec_refcount(session);
 818
 819         return ret;
 820
 821 err_ref_msg:
 822         nlmsg_free(msg);
 823 err_ref:
 824         l2tp_session_dec_refcount(session);
 825 err:
 826         return ret;
 827 }
 828
 829 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
 830 {
 831         struct net *net = sock_net(skb->sk);
 832         struct l2tp_session *session;
 833         struct l2tp_tunnel *tunnel = NULL;
 834         int ti = cb->args[0];
 835         int si = cb->args[1];
 836
 837         for (;;) {
 838                 if (!tunnel) {
 839                         tunnel = l2tp_tunnel_get_nth(net, ti);
 840                         if (!tunnel)
 841                                 goto out;
 842                 }
 843
 844                 session = l2tp_session_get_nth(tunnel, si);
 845                 if (!session) {
 846                         ti++;
 847                         l2tp_tunnel_dec_refcount(tunnel);
 848                         tunnel = NULL;
 849                         si = 0;
 850                         continue;
 851                 }
 852
 853                 if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
 854                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
 855                                          session, L2TP_CMD_SESSION_GET) < 0) {
 856                         l2tp_session_dec_refcount(session);
 857                         l2tp_tunnel_dec_refcount(tunnel);
 858                         break;
 859                 }
 860                 l2tp_session_dec_refcount(session);
 861
 862                 si++;
 863         }
 864
 865 out:
 866         cb->args[0] = ti;
 867         cb->args[1] = si;
 868
 869         return skb->len;
 870 }
 871
 872 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
 873         [L2TP_ATTR_NONE]                = { .type = NLA_UNSPEC, },
 874         [L2TP_ATTR_PW_TYPE]             = { .type = NLA_U16, },
 875         [L2TP_ATTR_ENCAP_TYPE]          = { .type = NLA_U16, },
 876         [L2TP_ATTR_OFFSET]              = { .type = NLA_U16, },
 877         [L2TP_ATTR_DATA_SEQ]            = { .type = NLA_U8, },
 878         [L2TP_ATTR_L2SPEC_TYPE]         = { .type = NLA_U8, },
 879         [L2TP_ATTR_L2SPEC_LEN]          = { .type = NLA_U8, },
 880         [L2TP_ATTR_PROTO_VERSION]       = { .type = NLA_U8, },
 881         [L2TP_ATTR_CONN_ID]             = { .type = NLA_U32, },
 882         [L2TP_ATTR_PEER_CONN_ID]        = { .type = NLA_U32, },
 883         [L2TP_ATTR_SESSION_ID]          = { .type = NLA_U32, },
 884         [L2TP_ATTR_PEER_SESSION_ID]     = { .type = NLA_U32, },
 885         [L2TP_ATTR_UDP_CSUM]            = { .type = NLA_U8, },
 886         [L2TP_ATTR_VLAN_ID]             = { .type = NLA_U16, },
 887         [L2TP_ATTR_DEBUG]               = { .type = NLA_U32, },
 888         [L2TP_ATTR_RECV_SEQ]            = { .type = NLA_U8, },
 889         [L2TP_ATTR_SEND_SEQ]            = { .type = NLA_U8, },
 890         [L2TP_ATTR_LNS_MODE]            = { .type = NLA_U8, },
 891         [L2TP_ATTR_USING_IPSEC]         = { .type = NLA_U8, },
 892         [L2TP_ATTR_RECV_TIMEOUT]        = { .type = NLA_MSECS, },
 893         [L2TP_ATTR_FD]                  = { .type = NLA_U32, },
 894         [L2TP_ATTR_IP_SADDR]            = { .type = NLA_U32, },
 895         [L2TP_ATTR_IP_DADDR]            = { .type = NLA_U32, },
 896         [L2TP_ATTR_UDP_SPORT]           = { .type = NLA_U16, },
 897         [L2TP_ATTR_UDP_DPORT]           = { .type = NLA_U16, },
 898         [L2TP_ATTR_MTU]                 = { .type = NLA_U16, },
 899         [L2TP_ATTR_MRU]                 = { .type = NLA_U16, },
 900         [L2TP_ATTR_STATS]               = { .type = NLA_NESTED, },
 901         [L2TP_ATTR_IP6_SADDR] = {
 902                 .type = NLA_BINARY,
 903                 .len = sizeof(struct in6_addr),
 904         },
 905         [L2TP_ATTR_IP6_DADDR] = {
 906                 .type = NLA_BINARY,
 907                 .len = sizeof(struct in6_addr),
 908         },
 909         [L2TP_ATTR_IFNAME] = {
 910                 .type = NLA_NUL_STRING,
 911                 .len = IFNAMSIZ - 1,
 912         },
 913         [L2TP_ATTR_COOKIE] = {
 914                 .type = NLA_BINARY,
 915                 .len = 8,
 916         },
 917         [L2TP_ATTR_PEER_COOKIE] = {
 918                 .type = NLA_BINARY,
 919                 .len = 8,
 920         },
 921 };
 922
 923 static const struct genl_small_ops l2tp_nl_ops[] = {
 924         {
 925                 .cmd = L2TP_CMD_NOOP,
 926                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 927                 .doit = l2tp_nl_cmd_noop,
 928                 /* can be retrieved by unprivileged users */
 929         },
 930         {
 931                 .cmd = L2TP_CMD_TUNNEL_CREATE,
 932                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 933                 .doit = l2tp_nl_cmd_tunnel_create,
 934                 .flags = GENL_UNS_ADMIN_PERM,
 935         },
 936         {
 937                 .cmd = L2TP_CMD_TUNNEL_DELETE,
 938                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 939                 .doit = l2tp_nl_cmd_tunnel_delete,
 940                 .flags = GENL_UNS_ADMIN_PERM,
 941         },
 942         {
 943                 .cmd = L2TP_CMD_TUNNEL_MODIFY,
 944                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 945                 .doit = l2tp_nl_cmd_tunnel_modify,
 946                 .flags = GENL_UNS_ADMIN_PERM,
 947         },
 948         {
 949                 .cmd = L2TP_CMD_TUNNEL_GET,
 950                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 951                 .doit = l2tp_nl_cmd_tunnel_get,
 952                 .dumpit = l2tp_nl_cmd_tunnel_dump,
 953                 .flags = GENL_UNS_ADMIN_PERM,
 954         },
 955         {
 956                 .cmd = L2TP_CMD_SESSION_CREATE,
 957                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 958                 .doit = l2tp_nl_cmd_session_create,
 959                 .flags = GENL_UNS_ADMIN_PERM,
 960         },
 961         {
 962                 .cmd = L2TP_CMD_SESSION_DELETE,
 963                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 964                 .doit = l2tp_nl_cmd_session_delete,
 965                 .flags = GENL_UNS_ADMIN_PERM,
 966         },
 967         {
 968                 .cmd = L2TP_CMD_SESSION_MODIFY,
 969                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 970                 .doit = l2tp_nl_cmd_session_modify,
 971                 .flags = GENL_UNS_ADMIN_PERM,
 972         },
 973         {
 974                 .cmd = L2TP_CMD_SESSION_GET,
 975                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 976                 .doit = l2tp_nl_cmd_session_get,
 977                 .dumpit = l2tp_nl_cmd_session_dump,
 978                 .flags = GENL_UNS_ADMIN_PERM,
 979         },
 980 };
 981
 982 static struct genl_family l2tp_nl_family __ro_after_init = {
 983         .name           = L2TP_GENL_NAME,
 984         .version        = L2TP_GENL_VERSION,
 985         .hdrsize        = 0,
 986         .maxattr        = L2TP_ATTR_MAX,
 987         .policy = l2tp_nl_policy,
 988         .netnsok        = true,
 989         .module         = THIS_MODULE,
 990         .small_ops      = l2tp_nl_ops,
 991         .n_small_ops    = ARRAY_SIZE(l2tp_nl_ops),
 992         .mcgrps         = l2tp_multicast_group,
 993         .n_mcgrps       = ARRAY_SIZE(l2tp_multicast_group),
 994 };
 995
 996 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
 997 {
 998         int ret;
 999
1000         ret = -EINVAL;
1001         if (pw_type >= __L2TP_PWTYPE_MAX)
1002                 goto err;
1003
1004         genl_lock();
1005         ret = -EBUSY;
1006         if (l2tp_nl_cmd_ops[pw_type])
1007                 goto out;
1008
1009         l2tp_nl_cmd_ops[pw_type] = ops;
1010         ret = 0;
1011
1012 out:
1013         genl_unlock();
1014 err:
1015         return ret;
1016 }
1017 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1018
1019 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1020 {
1021         if (pw_type < __L2TP_PWTYPE_MAX) {
1022                 genl_lock();
1023                 l2tp_nl_cmd_ops[pw_type] = NULL;
1024                 genl_unlock();
1025         }
1026 }
1027 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1028
1029 static int __init l2tp_nl_init(void)
1030 {
1031         pr_info("L2TP netlink interface\n");
1032         return genl_register_family(&l2tp_nl_family);
1033 }
1034
1035 static void l2tp_nl_cleanup(void)
1036 {
1037         genl_unregister_family(&l2tp_nl_family);
1038 }
1039
1040 module_init(l2tp_nl_init);
1041 module_exit(l2tp_nl_cleanup);
1042
1043 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1044 MODULE_DESCRIPTION("L2TP netlink");
1045 MODULE_LICENSE("GPL");
1046 MODULE_VERSION("1.0");
1047 MODULE_ALIAS_GENL_FAMILY("l2tp");