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                 goto nla_put_failure;
 433         nla_nest_end(skb, nest);
 434
 435         if (l2tp_nl_tunnel_send_addr(skb, tunnel))
 436                 goto nla_put_failure;
 437
 438         genlmsg_end(skb, hdr);
 439         return 0;
 440
 441 nla_put_failure:
 442         genlmsg_cancel(skb, hdr);
 443         return -1;
 444 }
 445
 446 static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info)
 447 {
 448         struct l2tp_tunnel *tunnel;
 449         struct sk_buff *msg;
 450         u32 tunnel_id;
 451         int ret = -ENOBUFS;
 452         struct net *net = genl_info_net(info);
 453
 454         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 455                 ret = -EINVAL;
 456                 goto err;
 457         }
 458
 459         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 460
 461         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 462         if (!msg) {
 463                 ret = -ENOMEM;
 464                 goto err;
 465         }
 466
 467         tunnel = l2tp_tunnel_get(net, tunnel_id);
 468         if (!tunnel) {
 469                 ret = -ENODEV;
 470                 goto err_nlmsg;
 471         }
 472
 473         ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
 474                                   NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
 475         if (ret < 0)
 476                 goto err_nlmsg_tunnel;
 477
 478         l2tp_tunnel_dec_refcount(tunnel);
 479
 480         return genlmsg_unicast(net, msg, info->snd_portid);
 481
 482 err_nlmsg_tunnel:
 483         l2tp_tunnel_dec_refcount(tunnel);
 484 err_nlmsg:
 485         nlmsg_free(msg);
 486 err:
 487         return ret;
 488 }
 489
 490 static int l2tp_nl_cmd_tunnel_dump(struct sk_buff *skb, struct netlink_callback *cb)
 491 {
 492         int ti = cb->args[0];
 493         struct l2tp_tunnel *tunnel;
 494         struct net *net = sock_net(skb->sk);
 495
 496         for (;;) {
 497                 tunnel = l2tp_tunnel_get_nth(net, ti);
 498                 if (!tunnel)
 499                         goto out;
 500
 501                 if (l2tp_nl_tunnel_send(skb, NETLINK_CB(cb->skb).portid,
 502                                         cb->nlh->nlmsg_seq, NLM_F_MULTI,
 503                                         tunnel, L2TP_CMD_TUNNEL_GET) < 0) {
 504                         l2tp_tunnel_dec_refcount(tunnel);
 505                         goto out;
 506                 }
 507                 l2tp_tunnel_dec_refcount(tunnel);
 508
 509                 ti++;
 510         }
 511
 512 out:
 513         cb->args[0] = ti;
 514
 515         return skb->len;
 516 }
 517
 518 static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *info)
 519 {
 520         u32 tunnel_id = 0;
 521         u32 session_id;
 522         u32 peer_session_id;
 523         int ret = 0;
 524         struct l2tp_tunnel *tunnel;
 525         struct l2tp_session *session;
 526         struct l2tp_session_cfg cfg = { 0, };
 527         struct net *net = genl_info_net(info);
 528
 529         if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 530                 ret = -EINVAL;
 531                 goto out;
 532         }
 533
 534         tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 535         tunnel = l2tp_tunnel_get(net, tunnel_id);
 536         if (!tunnel) {
 537                 ret = -ENODEV;
 538                 goto out;
 539         }
 540
 541         if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
 542                 ret = -EINVAL;
 543                 goto out_tunnel;
 544         }
 545         session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
 546
 547         if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
 548                 ret = -EINVAL;
 549                 goto out_tunnel;
 550         }
 551         peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
 552
 553         if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
 554                 ret = -EINVAL;
 555                 goto out_tunnel;
 556         }
 557         cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
 558         if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
 559                 ret = -EINVAL;
 560                 goto out_tunnel;
 561         }
 562
 563         /* L2TPv2 only accepts PPP pseudo-wires */
 564         if (tunnel->version == 2 && cfg.pw_type != L2TP_PWTYPE_PPP) {
 565                 ret = -EPROTONOSUPPORT;
 566                 goto out_tunnel;
 567         }
 568
 569         if (tunnel->version > 2) {
 570                 if (info->attrs[L2TP_ATTR_L2SPEC_TYPE]) {
 571                         cfg.l2specific_type = nla_get_u8(info->attrs[L2TP_ATTR_L2SPEC_TYPE]);
 572                         if (cfg.l2specific_type != L2TP_L2SPECTYPE_DEFAULT &&
 573                             cfg.l2specific_type != L2TP_L2SPECTYPE_NONE) {
 574                                 ret = -EINVAL;
 575                                 goto out_tunnel;
 576                         }
 577                 } else {
 578                         cfg.l2specific_type = L2TP_L2SPECTYPE_DEFAULT;
 579                 }
 580
 581                 if (info->attrs[L2TP_ATTR_COOKIE]) {
 582                         u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
 583
 584                         if (len > 8) {
 585                                 ret = -EINVAL;
 586                                 goto out_tunnel;
 587                         }
 588                         cfg.cookie_len = len;
 589                         memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
 590                 }
 591                 if (info->attrs[L2TP_ATTR_PEER_COOKIE]) {
 592                         u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
 593
 594                         if (len > 8) {
 595                                 ret = -EINVAL;
 596                                 goto out_tunnel;
 597                         }
 598                         cfg.peer_cookie_len = len;
 599                         memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
 600                 }
 601                 if (info->attrs[L2TP_ATTR_IFNAME])
 602                         cfg.ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
 603         }
 604
 605         if (info->attrs[L2TP_ATTR_RECV_SEQ])
 606                 cfg.recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 607
 608         if (info->attrs[L2TP_ATTR_SEND_SEQ])
 609                 cfg.send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
 610
 611         if (info->attrs[L2TP_ATTR_LNS_MODE])
 612                 cfg.lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
 613
 614         if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
 615                 cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
 616
 617 #ifdef CONFIG_MODULES
 618         if (!l2tp_nl_cmd_ops[cfg.pw_type]) {
 619                 genl_unlock();
 620                 request_module("net-l2tp-type-%u", cfg.pw_type);
 621                 genl_lock();
 622         }
 623 #endif
 624         if (!l2tp_nl_cmd_ops[cfg.pw_type] || !l2tp_nl_cmd_ops[cfg.pw_type]->session_create) {
 625                 ret = -EPROTONOSUPPORT;
 626                 goto out_tunnel;
 627         }
 628
 629         ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
 630                                                            session_id,
 631                                                            peer_session_id,
 632                                                            &cfg);
 633
 634         if (ret >= 0) {
 635                 session = l2tp_tunnel_get_session(tunnel, session_id);
 636                 if (session) {
 637                         ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 638                                                   L2TP_CMD_SESSION_CREATE);
 639                         l2tp_session_dec_refcount(session);
 640                 }
 641         }
 642
 643 out_tunnel:
 644         l2tp_tunnel_dec_refcount(tunnel);
 645 out:
 646         return ret;
 647 }
 648
 649 static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *info)
 650 {
 651         int ret = 0;
 652         struct l2tp_session *session;
 653         u16 pw_type;
 654
 655         session = l2tp_nl_session_get(info);
 656         if (!session) {
 657                 ret = -ENODEV;
 658                 goto out;
 659         }
 660
 661         l2tp_session_notify(&l2tp_nl_family, info,
 662                             session, L2TP_CMD_SESSION_DELETE);
 663
 664         pw_type = session->pwtype;
 665         if (pw_type < __L2TP_PWTYPE_MAX)
 666                 if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
 667                         l2tp_nl_cmd_ops[pw_type]->session_delete(session);
 668
 669         l2tp_session_dec_refcount(session);
 670
 671 out:
 672         return ret;
 673 }
 674
 675 static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *info)
 676 {
 677         int ret = 0;
 678         struct l2tp_session *session;
 679
 680         session = l2tp_nl_session_get(info);
 681         if (!session) {
 682                 ret = -ENODEV;
 683                 goto out;
 684         }
 685
 686         if (info->attrs[L2TP_ATTR_RECV_SEQ])
 687                 session->recv_seq = nla_get_u8(info->attrs[L2TP_ATTR_RECV_SEQ]);
 688
 689         if (info->attrs[L2TP_ATTR_SEND_SEQ]) {
 690                 session->send_seq = nla_get_u8(info->attrs[L2TP_ATTR_SEND_SEQ]);
 691                 l2tp_session_set_header_len(session, session->tunnel->version);
 692         }
 693
 694         if (info->attrs[L2TP_ATTR_LNS_MODE])
 695                 session->lns_mode = nla_get_u8(info->attrs[L2TP_ATTR_LNS_MODE]);
 696
 697         if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
 698                 session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
 699
 700         ret = l2tp_session_notify(&l2tp_nl_family, info,
 701                                   session, L2TP_CMD_SESSION_MODIFY);
 702
 703         l2tp_session_dec_refcount(session);
 704
 705 out:
 706         return ret;
 707 }
 708
 709 static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int flags,
 710                                 struct l2tp_session *session, u8 cmd)
 711 {
 712         void *hdr;
 713         struct nlattr *nest;
 714         struct l2tp_tunnel *tunnel = session->tunnel;
 715
 716         hdr = genlmsg_put(skb, portid, seq, &l2tp_nl_family, flags, cmd);
 717         if (!hdr)
 718                 return -EMSGSIZE;
 719
 720         if (nla_put_u32(skb, L2TP_ATTR_CONN_ID, tunnel->tunnel_id) ||
 721             nla_put_u32(skb, L2TP_ATTR_SESSION_ID, session->session_id) ||
 722             nla_put_u32(skb, L2TP_ATTR_PEER_CONN_ID, tunnel->peer_tunnel_id) ||
 723             nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID, session->peer_session_id) ||
 724             nla_put_u32(skb, L2TP_ATTR_DEBUG, 0) ||
 725             nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
 726                 goto nla_put_failure;
 727
 728         if ((session->ifname[0] &&
 729              nla_put_string(skb, L2TP_ATTR_IFNAME, session->ifname)) ||
 730             (session->cookie_len &&
 731              nla_put(skb, L2TP_ATTR_COOKIE, session->cookie_len, session->cookie)) ||
 732             (session->peer_cookie_len &&
 733              nla_put(skb, L2TP_ATTR_PEER_COOKIE, session->peer_cookie_len, session->peer_cookie)) ||
 734             nla_put_u8(skb, L2TP_ATTR_RECV_SEQ, session->recv_seq) ||
 735             nla_put_u8(skb, L2TP_ATTR_SEND_SEQ, session->send_seq) ||
 736             nla_put_u8(skb, L2TP_ATTR_LNS_MODE, session->lns_mode) ||
 737             (l2tp_tunnel_uses_xfrm(tunnel) &&
 738              nla_put_u8(skb, L2TP_ATTR_USING_IPSEC, 1)) ||
 739             (session->reorder_timeout &&
 740              nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT,
 741                            session->reorder_timeout, L2TP_ATTR_PAD)))
 742                 goto nla_put_failure;
 743
 744         nest = nla_nest_start_noflag(skb, L2TP_ATTR_STATS);
 745         if (!nest)
 746                 goto nla_put_failure;
 747
 748         if (nla_put_u64_64bit(skb, L2TP_ATTR_TX_PACKETS,
 749                               atomic_long_read(&session->stats.tx_packets),
 750                               L2TP_ATTR_STATS_PAD) ||
 751             nla_put_u64_64bit(skb, L2TP_ATTR_TX_BYTES,
 752                               atomic_long_read(&session->stats.tx_bytes),
 753                               L2TP_ATTR_STATS_PAD) ||
 754             nla_put_u64_64bit(skb, L2TP_ATTR_TX_ERRORS,
 755                               atomic_long_read(&session->stats.tx_errors),
 756                               L2TP_ATTR_STATS_PAD) ||
 757             nla_put_u64_64bit(skb, L2TP_ATTR_RX_PACKETS,
 758                               atomic_long_read(&session->stats.rx_packets),
 759                               L2TP_ATTR_STATS_PAD) ||
 760             nla_put_u64_64bit(skb, L2TP_ATTR_RX_BYTES,
 761                               atomic_long_read(&session->stats.rx_bytes),
 762                               L2TP_ATTR_STATS_PAD) ||
 763             nla_put_u64_64bit(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
 764                               atomic_long_read(&session->stats.rx_seq_discards),
 765                               L2TP_ATTR_STATS_PAD) ||
 766             nla_put_u64_64bit(skb, L2TP_ATTR_RX_COOKIE_DISCARDS,
 767                               atomic_long_read(&session->stats.rx_cookie_discards),
 768                               L2TP_ATTR_STATS_PAD) ||
 769             nla_put_u64_64bit(skb, L2TP_ATTR_RX_OOS_PACKETS,
 770                               atomic_long_read(&session->stats.rx_oos_packets),
 771                               L2TP_ATTR_STATS_PAD) ||
 772             nla_put_u64_64bit(skb, L2TP_ATTR_RX_ERRORS,
 773                               atomic_long_read(&session->stats.rx_errors),
 774                               L2TP_ATTR_STATS_PAD))
 775                 goto nla_put_failure;
 776         nla_nest_end(skb, nest);
 777
 778         genlmsg_end(skb, hdr);
 779         return 0;
 780
 781  nla_put_failure:
 782         genlmsg_cancel(skb, hdr);
 783         return -1;
 784 }
 785
 786 static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
 787 {
 788         struct l2tp_session *session;
 789         struct sk_buff *msg;
 790         int ret;
 791
 792         session = l2tp_nl_session_get(info);
 793         if (!session) {
 794                 ret = -ENODEV;
 795                 goto err;
 796         }
 797
 798         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 799         if (!msg) {
 800                 ret = -ENOMEM;
 801                 goto err_ref;
 802         }
 803
 804         ret = l2tp_nl_session_send(msg, info->snd_portid, info->snd_seq,
 805                                    0, session, L2TP_CMD_SESSION_GET);
 806         if (ret < 0)
 807                 goto err_ref_msg;
 808
 809         ret = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
 810
 811         l2tp_session_dec_refcount(session);
 812
 813         return ret;
 814
 815 err_ref_msg:
 816         nlmsg_free(msg);
 817 err_ref:
 818         l2tp_session_dec_refcount(session);
 819 err:
 820         return ret;
 821 }
 822
 823 static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback *cb)
 824 {
 825         struct net *net = sock_net(skb->sk);
 826         struct l2tp_session *session;
 827         struct l2tp_tunnel *tunnel = NULL;
 828         int ti = cb->args[0];
 829         int si = cb->args[1];
 830
 831         for (;;) {
 832                 if (!tunnel) {
 833                         tunnel = l2tp_tunnel_get_nth(net, ti);
 834                         if (!tunnel)
 835                                 goto out;
 836                 }
 837
 838                 session = l2tp_session_get_nth(tunnel, si);
 839                 if (!session) {
 840                         ti++;
 841                         l2tp_tunnel_dec_refcount(tunnel);
 842                         tunnel = NULL;
 843                         si = 0;
 844                         continue;
 845                 }
 846
 847                 if (l2tp_nl_session_send(skb, NETLINK_CB(cb->skb).portid,
 848                                          cb->nlh->nlmsg_seq, NLM_F_MULTI,
 849                                          session, L2TP_CMD_SESSION_GET) < 0) {
 850                         l2tp_session_dec_refcount(session);
 851                         l2tp_tunnel_dec_refcount(tunnel);
 852                         break;
 853                 }
 854                 l2tp_session_dec_refcount(session);
 855
 856                 si++;
 857         }
 858
 859 out:
 860         cb->args[0] = ti;
 861         cb->args[1] = si;
 862
 863         return skb->len;
 864 }
 865
 866 static const struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
 867         [L2TP_ATTR_NONE]                = { .type = NLA_UNSPEC, },
 868         [L2TP_ATTR_PW_TYPE]             = { .type = NLA_U16, },
 869         [L2TP_ATTR_ENCAP_TYPE]          = { .type = NLA_U16, },
 870         [L2TP_ATTR_OFFSET]              = { .type = NLA_U16, },
 871         [L2TP_ATTR_DATA_SEQ]            = { .type = NLA_U8, },
 872         [L2TP_ATTR_L2SPEC_TYPE]         = { .type = NLA_U8, },
 873         [L2TP_ATTR_L2SPEC_LEN]          = { .type = NLA_U8, },
 874         [L2TP_ATTR_PROTO_VERSION]       = { .type = NLA_U8, },
 875         [L2TP_ATTR_CONN_ID]             = { .type = NLA_U32, },
 876         [L2TP_ATTR_PEER_CONN_ID]        = { .type = NLA_U32, },
 877         [L2TP_ATTR_SESSION_ID]          = { .type = NLA_U32, },
 878         [L2TP_ATTR_PEER_SESSION_ID]     = { .type = NLA_U32, },
 879         [L2TP_ATTR_UDP_CSUM]            = { .type = NLA_U8, },
 880         [L2TP_ATTR_VLAN_ID]             = { .type = NLA_U16, },
 881         [L2TP_ATTR_DEBUG]               = { .type = NLA_U32, },
 882         [L2TP_ATTR_RECV_SEQ]            = { .type = NLA_U8, },
 883         [L2TP_ATTR_SEND_SEQ]            = { .type = NLA_U8, },
 884         [L2TP_ATTR_LNS_MODE]            = { .type = NLA_U8, },
 885         [L2TP_ATTR_USING_IPSEC]         = { .type = NLA_U8, },
 886         [L2TP_ATTR_RECV_TIMEOUT]        = { .type = NLA_MSECS, },
 887         [L2TP_ATTR_FD]                  = { .type = NLA_U32, },
 888         [L2TP_ATTR_IP_SADDR]            = { .type = NLA_U32, },
 889         [L2TP_ATTR_IP_DADDR]            = { .type = NLA_U32, },
 890         [L2TP_ATTR_UDP_SPORT]           = { .type = NLA_U16, },
 891         [L2TP_ATTR_UDP_DPORT]           = { .type = NLA_U16, },
 892         [L2TP_ATTR_MTU]                 = { .type = NLA_U16, },
 893         [L2TP_ATTR_MRU]                 = { .type = NLA_U16, },
 894         [L2TP_ATTR_STATS]               = { .type = NLA_NESTED, },
 895         [L2TP_ATTR_IP6_SADDR] = {
 896                 .type = NLA_BINARY,
 897                 .len = sizeof(struct in6_addr),
 898         },
 899         [L2TP_ATTR_IP6_DADDR] = {
 900                 .type = NLA_BINARY,
 901                 .len = sizeof(struct in6_addr),
 902         },
 903         [L2TP_ATTR_IFNAME] = {
 904                 .type = NLA_NUL_STRING,
 905                 .len = IFNAMSIZ - 1,
 906         },
 907         [L2TP_ATTR_COOKIE] = {
 908                 .type = NLA_BINARY,
 909                 .len = 8,
 910         },
 911         [L2TP_ATTR_PEER_COOKIE] = {
 912                 .type = NLA_BINARY,
 913                 .len = 8,
 914         },
 915 };
 916
 917 static const struct genl_small_ops l2tp_nl_ops[] = {
 918         {
 919                 .cmd = L2TP_CMD_NOOP,
 920                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 921                 .doit = l2tp_nl_cmd_noop,
 922                 /* can be retrieved by unprivileged users */
 923         },
 924         {
 925                 .cmd = L2TP_CMD_TUNNEL_CREATE,
 926                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 927                 .doit = l2tp_nl_cmd_tunnel_create,
 928                 .flags = GENL_UNS_ADMIN_PERM,
 929         },
 930         {
 931                 .cmd = L2TP_CMD_TUNNEL_DELETE,
 932                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 933                 .doit = l2tp_nl_cmd_tunnel_delete,
 934                 .flags = GENL_UNS_ADMIN_PERM,
 935         },
 936         {
 937                 .cmd = L2TP_CMD_TUNNEL_MODIFY,
 938                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 939                 .doit = l2tp_nl_cmd_tunnel_modify,
 940                 .flags = GENL_UNS_ADMIN_PERM,
 941         },
 942         {
 943                 .cmd = L2TP_CMD_TUNNEL_GET,
 944                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 945                 .doit = l2tp_nl_cmd_tunnel_get,
 946                 .dumpit = l2tp_nl_cmd_tunnel_dump,
 947                 .flags = GENL_UNS_ADMIN_PERM,
 948         },
 949         {
 950                 .cmd = L2TP_CMD_SESSION_CREATE,
 951                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 952                 .doit = l2tp_nl_cmd_session_create,
 953                 .flags = GENL_UNS_ADMIN_PERM,
 954         },
 955         {
 956                 .cmd = L2TP_CMD_SESSION_DELETE,
 957                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 958                 .doit = l2tp_nl_cmd_session_delete,
 959                 .flags = GENL_UNS_ADMIN_PERM,
 960         },
 961         {
 962                 .cmd = L2TP_CMD_SESSION_MODIFY,
 963                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 964                 .doit = l2tp_nl_cmd_session_modify,
 965                 .flags = GENL_UNS_ADMIN_PERM,
 966         },
 967         {
 968                 .cmd = L2TP_CMD_SESSION_GET,
 969                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 970                 .doit = l2tp_nl_cmd_session_get,
 971                 .dumpit = l2tp_nl_cmd_session_dump,
 972                 .flags = GENL_UNS_ADMIN_PERM,
 973         },
 974 };
 975
 976 static struct genl_family l2tp_nl_family __ro_after_init = {
 977         .name           = L2TP_GENL_NAME,
 978         .version        = L2TP_GENL_VERSION,
 979         .hdrsize        = 0,
 980         .maxattr        = L2TP_ATTR_MAX,
 981         .policy = l2tp_nl_policy,
 982         .netnsok        = true,
 983         .module         = THIS_MODULE,
 984         .small_ops      = l2tp_nl_ops,
 985         .n_small_ops    = ARRAY_SIZE(l2tp_nl_ops),
 986         .mcgrps         = l2tp_multicast_group,
 987         .n_mcgrps       = ARRAY_SIZE(l2tp_multicast_group),
 988 };
 989
 990 int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops)
 991 {
 992         int ret;
 993
 994         ret = -EINVAL;
 995         if (pw_type >= __L2TP_PWTYPE_MAX)
 996                 goto err;
 997
 998         genl_lock();
 999         ret = -EBUSY;
1000         if (l2tp_nl_cmd_ops[pw_type])
1001                 goto out;
1002
1003         l2tp_nl_cmd_ops[pw_type] = ops;
1004         ret = 0;
1005
1006 out:
1007         genl_unlock();
1008 err:
1009         return ret;
1010 }
1011 EXPORT_SYMBOL_GPL(l2tp_nl_register_ops);
1012
1013 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type)
1014 {
1015         if (pw_type < __L2TP_PWTYPE_MAX) {
1016                 genl_lock();
1017                 l2tp_nl_cmd_ops[pw_type] = NULL;
1018                 genl_unlock();
1019         }
1020 }
1021 EXPORT_SYMBOL_GPL(l2tp_nl_unregister_ops);
1022
1023 static int __init l2tp_nl_init(void)
1024 {
1025         pr_info("L2TP netlink interface\n");
1026         return genl_register_family(&l2tp_nl_family);
1027 }
1028
1029 static void l2tp_nl_cleanup(void)
1030 {
1031         genl_unregister_family(&l2tp_nl_family);
1032 }
1033
1034 module_init(l2tp_nl_init);
1035 module_exit(l2tp_nl_cleanup);
1036
1037 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
1038 MODULE_DESCRIPTION("L2TP netlink");
1039 MODULE_LICENSE("GPL");
1040 MODULE_VERSION("1.0");
1041 MODULE_ALIAS_GENL_FAMILY("l2tp");