1/* 2 * L2TP core. 3 * 4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 5 * 6 * This file contains some code of the original L2TPv2 pppol2tp 7 * driver, which has the following copyright: 8 * 9 * Authors: Martijn van Oosterhout <kleptog@svana.org> 10 * James Chapman (jchapman@katalix.com) 11 * Contributors: 12 * Michal Ostrowski <mostrows@speakeasy.net> 13 * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> 14 * David S. Miller (davem@redhat.com) 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 */ 20 21#include <linux/module.h> 22#include <linux/string.h> 23#include <linux/list.h> 24#include <linux/rculist.h> 25#include <linux/uaccess.h> 26 27#include <linux/kernel.h> 28#include <linux/spinlock.h> 29#include <linux/kthread.h> 30#include <linux/sched.h> 31#include <linux/slab.h> 32#include <linux/errno.h> 33#include <linux/jiffies.h> 34 35#include <linux/netdevice.h> 36#include <linux/net.h> 37#include <linux/inetdevice.h> 38#include <linux/skbuff.h> 39#include <linux/init.h> 40#include <linux/in.h> 41#include <linux/ip.h> 42#include <linux/udp.h> 43#include <linux/l2tp.h> 44#include <linux/hash.h> 45#include <linux/sort.h> 46#include <linux/file.h> 47#include <linux/nsproxy.h> 48#include <net/net_namespace.h> 49#include <net/netns/generic.h> 50#include <net/dst.h> 51#include <net/ip.h> 52#include <net/udp.h> 53#include <net/inet_common.h> 54#include <net/xfrm.h> 55#include <net/protocol.h> 56 57#include <asm/byteorder.h> 58#include <asm/atomic.h> 59 60#include "l2tp_core.h" 61 62#ifdef CTF_L2TP 63#include <ctf/hndctf.h> 64#endif 65 66#define L2TP_DRV_VERSION "V2.0" 67 68/* L2TP header constants */ 69#define L2TP_HDRFLAG_T 0x8000 70#define L2TP_HDRFLAG_L 0x4000 71#define L2TP_HDRFLAG_S 0x0800 72#define L2TP_HDRFLAG_O 0x0200 73#define L2TP_HDRFLAG_P 0x0100 74 75#define L2TP_HDR_VER_MASK 0x000F 76#define L2TP_HDR_VER_2 0x0002 77#define L2TP_HDR_VER_3 0x0003 78 79/* L2TPv3 default L2-specific sublayer */ 80#define L2TP_SLFLAG_S 0x40000000 81#define L2TP_SL_SEQ_MASK 0x00ffffff 82 83#define L2TP_HDR_SIZE_SEQ 10 84#define L2TP_HDR_SIZE_NOSEQ 6 85 86/* Default trace flags */ 87#define L2TP_DEFAULT_DEBUG_FLAGS 0 88 89#define PRINTK(_mask, _type, _lvl, _fmt, args...) \ 90 do { \ 91 if ((_mask) & (_type)) \ 92 printk(_lvl "L2TP: " _fmt, ##args); \ 93 } while (0) 94 95/* Private data stored for received packets in the skb. 96 */ 97struct l2tp_skb_cb { 98 u32 ns; 99 u16 has_seq; 100 u16 length; 101 unsigned long expires; 102}; 103 104#define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) 105 106static atomic_t l2tp_tunnel_count; 107static atomic_t l2tp_session_count; 108 109/* per-net private data for this module */ 110static unsigned int l2tp_net_id; 111struct l2tp_net { 112 struct list_head l2tp_tunnel_list; 113 spinlock_t l2tp_tunnel_list_lock; 114 struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; 115 spinlock_t l2tp_session_hlist_lock; 116}; 117 118static inline struct l2tp_net *l2tp_pernet(struct net *net) 119{ 120 BUG_ON(!net); 121 122 return net_generic(net, l2tp_net_id); 123} 124 125/* Session hash global list for L2TPv3. 126 * The session_id SHOULD be random according to RFC3931, but several 127 * L2TP implementations use incrementing session_ids. So we do a real 128 * hash on the session_id, rather than a simple bitmask. 129 */ 130static inline struct hlist_head * 131l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) 132{ 133 return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; 134 135} 136 137/* Lookup a session by id in the global session list 138 */ 139static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) 140{ 141 struct l2tp_net *pn = l2tp_pernet(net); 142 struct hlist_head *session_list = 143 l2tp_session_id_hash_2(pn, session_id); 144 struct l2tp_session *session; 145 struct hlist_node *walk; 146 147 rcu_read_lock_bh(); 148 hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) { 149 if (session->session_id == session_id) { 150 rcu_read_unlock_bh(); 151 return session; 152 } 153 } 154 rcu_read_unlock_bh(); 155 156 return NULL; 157} 158 159/* Session hash list. 160 * The session_id SHOULD be random according to RFC2661, but several 161 * L2TP implementations (Cisco and Microsoft) use incrementing 162 * session_ids. So we do a real hash on the session_id, rather than a 163 * simple bitmask. 164 */ 165static inline struct hlist_head * 166l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) 167{ 168 return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; 169} 170 171/* Lookup a session by id 172 */ 173struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) 174{ 175 struct hlist_head *session_list; 176 struct l2tp_session *session; 177 struct hlist_node *walk; 178 179 /* In L2TPv3, session_ids are unique over all tunnels and we 180 * sometimes need to look them up before we know the 181 * tunnel. 182 */ 183 if (tunnel == NULL) 184 return l2tp_session_find_2(net, session_id); 185 186 session_list = l2tp_session_id_hash(tunnel, session_id); 187 read_lock_bh(&tunnel->hlist_lock); 188 hlist_for_each_entry(session, walk, session_list, hlist) { 189 if (session->session_id == session_id) { 190 read_unlock_bh(&tunnel->hlist_lock); 191 return session; 192 } 193 } 194 read_unlock_bh(&tunnel->hlist_lock); 195 196 return NULL; 197} 198EXPORT_SYMBOL_GPL(l2tp_session_find); 199 200struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) 201{ 202 int hash; 203 struct hlist_node *walk; 204 struct l2tp_session *session; 205 int count = 0; 206 207 read_lock_bh(&tunnel->hlist_lock); 208 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 209 hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { 210 if (++count > nth) { 211 read_unlock_bh(&tunnel->hlist_lock); 212 return session; 213 } 214 } 215 } 216 217 read_unlock_bh(&tunnel->hlist_lock); 218 219 return NULL; 220} 221EXPORT_SYMBOL_GPL(l2tp_session_find_nth); 222 223/* Lookup a session by interface name. 224 * This is very inefficient but is only used by management interfaces. 225 */ 226struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname) 227{ 228 struct l2tp_net *pn = l2tp_pernet(net); 229 int hash; 230 struct hlist_node *walk; 231 struct l2tp_session *session; 232 233 rcu_read_lock_bh(); 234 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { 235 hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) { 236 if (!strcmp(session->ifname, ifname)) { 237 rcu_read_unlock_bh(); 238 return session; 239 } 240 } 241 } 242 243 rcu_read_unlock_bh(); 244 245 return NULL; 246} 247EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname); 248 249/* Lookup a tunnel by id 250 */ 251struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) 252{ 253 struct l2tp_tunnel *tunnel; 254 struct l2tp_net *pn = l2tp_pernet(net); 255 256 rcu_read_lock_bh(); 257 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 258 if (tunnel->tunnel_id == tunnel_id) { 259 rcu_read_unlock_bh(); 260 return tunnel; 261 } 262 } 263 rcu_read_unlock_bh(); 264 265 return NULL; 266} 267EXPORT_SYMBOL_GPL(l2tp_tunnel_find); 268 269struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) 270{ 271 struct l2tp_net *pn = l2tp_pernet(net); 272 struct l2tp_tunnel *tunnel; 273 int count = 0; 274 275 rcu_read_lock_bh(); 276 list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 277 if (++count > nth) { 278 rcu_read_unlock_bh(); 279 return tunnel; 280 } 281 } 282 283 rcu_read_unlock_bh(); 284 285 return NULL; 286} 287EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); 288 289/***************************************************************************** 290 * Receive data handling 291 *****************************************************************************/ 292 293/* Queue a skb in order. We come here only if the skb has an L2TP sequence 294 * number. 295 */ 296static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) 297{ 298 struct sk_buff *skbp; 299 struct sk_buff *tmp; 300 u32 ns = L2TP_SKB_CB(skb)->ns; 301 302 spin_lock_bh(&session->reorder_q.lock); 303 skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { 304 if (L2TP_SKB_CB(skbp)->ns > ns) { 305 __skb_queue_before(&session->reorder_q, skbp, skb); 306 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 307 "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", 308 session->name, ns, L2TP_SKB_CB(skbp)->ns, 309 skb_queue_len(&session->reorder_q)); 310 session->stats.rx_oos_packets++; 311 goto out; 312 } 313 } 314 315 __skb_queue_tail(&session->reorder_q, skb); 316 317out: 318 spin_unlock_bh(&session->reorder_q.lock); 319} 320 321/* Dequeue a single skb. 322 */ 323static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) 324{ 325 struct l2tp_tunnel *tunnel = session->tunnel; 326 int length = L2TP_SKB_CB(skb)->length; 327 328 /* We're about to requeue the skb, so return resources 329 * to its current owner (a socket receive buffer). 330 */ 331 skb_orphan(skb); 332 333 tunnel->stats.rx_packets++; 334 tunnel->stats.rx_bytes += length; 335 session->stats.rx_packets++; 336 session->stats.rx_bytes += length; 337 338 if (L2TP_SKB_CB(skb)->has_seq) { 339 /* Bump our Nr */ 340 session->nr++; 341 if (tunnel->version == L2TP_HDR_VER_2) 342 session->nr &= 0xffff; 343 else 344 session->nr &= 0xffffff; 345 346 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 347 "%s: updated nr to %hu\n", session->name, session->nr); 348 } 349 350 /* call private receive handler */ 351 if (session->recv_skb != NULL) 352 (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); 353 else 354 kfree_skb(skb); 355 356 if (session->deref) 357 (*session->deref)(session); 358} 359 360/* Dequeue skbs from the session's reorder_q, subject to packet order. 361 * Skbs that have been in the queue for too long are simply discarded. 362 */ 363static void l2tp_recv_dequeue(struct l2tp_session *session) 364{ 365 struct sk_buff *skb; 366 struct sk_buff *tmp; 367 368 /* If the pkt at the head of the queue has the nr that we 369 * expect to send up next, dequeue it and any other 370 * in-sequence packets behind it. 371 */ 372 spin_lock_bh(&session->reorder_q.lock); 373 skb_queue_walk_safe(&session->reorder_q, skb, tmp) { 374 if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { 375 session->stats.rx_seq_discards++; 376 session->stats.rx_errors++; 377 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 378 "%s: oos pkt %u len %d discarded (too old), " 379 "waiting for %u, reorder_q_len=%d\n", 380 session->name, L2TP_SKB_CB(skb)->ns, 381 L2TP_SKB_CB(skb)->length, session->nr, 382 skb_queue_len(&session->reorder_q)); 383 __skb_unlink(skb, &session->reorder_q); 384 kfree_skb(skb); 385 if (session->deref) 386 (*session->deref)(session); 387 continue; 388 } 389 390 if (L2TP_SKB_CB(skb)->has_seq) { 391 if (L2TP_SKB_CB(skb)->ns != session->nr) { 392 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 393 "%s: holding oos pkt %u len %d, " 394 "waiting for %u, reorder_q_len=%d\n", 395 session->name, L2TP_SKB_CB(skb)->ns, 396 L2TP_SKB_CB(skb)->length, session->nr, 397 skb_queue_len(&session->reorder_q)); 398 goto out; 399 } 400 } 401 __skb_unlink(skb, &session->reorder_q); 402 403 /* Process the skb. We release the queue lock while we 404 * do so to let other contexts process the queue. 405 */ 406 spin_unlock_bh(&session->reorder_q.lock); 407 l2tp_recv_dequeue_skb(session, skb); 408 spin_lock_bh(&session->reorder_q.lock); 409 } 410 411out: 412 spin_unlock_bh(&session->reorder_q.lock); 413} 414 415static inline int l2tp_verify_udp_checksum(struct sock *sk, 416 struct sk_buff *skb) 417{ 418 struct udphdr *uh = udp_hdr(skb); 419 u16 ulen = ntohs(uh->len); 420 struct inet_sock *inet; 421 __wsum psum; 422 423 if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check) 424 return 0; 425 426 inet = inet_sk(sk); 427 psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen, 428 IPPROTO_UDP, 0); 429 430 if ((skb->ip_summed == CHECKSUM_COMPLETE) && 431 !csum_fold(csum_add(psum, skb->csum))) 432 return 0; 433 434 skb->csum = psum; 435 436 return __skb_checksum_complete(skb); 437} 438 439/* Do receive processing of L2TP data frames. We handle both L2TPv2 440 * and L2TPv3 data frames here. 441 * 442 * L2TPv2 Data Message Header 443 * 444 * 0 1 2 3 445 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 446 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 447 * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | 448 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 * | Tunnel ID | Session ID | 450 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 * | Ns (opt) | Nr (opt) | 452 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 453 * | Offset Size (opt) | Offset pad... (opt) 454 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 455 * 456 * Data frames are marked by T=0. All other fields are the same as 457 * those in L2TP control frames. 458 * 459 * L2TPv3 Data Message Header 460 * 461 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 * | L2TP Session Header | 463 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 464 * | L2-Specific Sublayer | 465 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 466 * | Tunnel Payload ... 467 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 * 469 * L2TPv3 Session Header Over IP 470 * 471 * 0 1 2 3 472 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 473 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 474 * | Session ID | 475 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 476 * | Cookie (optional, maximum 64 bits)... 477 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 478 * | 479 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 480 * 481 * L2TPv3 L2-Specific Sublayer Format 482 * 483 * 0 1 2 3 484 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 485 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 486 * |x|S|x|x|x|x|x|x| Sequence Number | 487 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 488 * 489 * Cookie value, sublayer format and offset (pad) are negotiated with 490 * the peer when the session is set up. Unlike L2TPv2, we do not need 491 * to parse the packet header to determine if optional fields are 492 * present. 493 * 494 * Caller must already have parsed the frame and determined that it is 495 * a data (not control) frame before coming here. Fields up to the 496 * session-id have already been parsed and ptr points to the data 497 * after the session-id. 498 */ 499void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 500 unsigned char *ptr, unsigned char *optr, u16 hdrflags, 501 int length, int (*payload_hook)(struct sk_buff *skb)) 502{ 503 struct l2tp_tunnel *tunnel = session->tunnel; 504 int offset; 505 u32 ns, nr; 506 507 /* The ref count is increased since we now hold a pointer to 508 * the session. Take care to decrement the refcnt when exiting 509 * this function from now on... 510 */ 511 l2tp_session_inc_refcount(session); 512 if (session->ref) 513 (*session->ref)(session); 514 515 /* Parse and check optional cookie */ 516 if (session->peer_cookie_len > 0) { 517 if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { 518 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 519 "%s: cookie mismatch (%u/%u). Discarding.\n", 520 tunnel->name, tunnel->tunnel_id, session->session_id); 521 session->stats.rx_cookie_discards++; 522 goto discard; 523 } 524 ptr += session->peer_cookie_len; 525 } 526 527 /* Handle the optional sequence numbers. Sequence numbers are 528 * in different places for L2TPv2 and L2TPv3. 529 * 530 * If we are the LAC, enable/disable sequence numbers under 531 * the control of the LNS. If no sequence numbers present but 532 * we were expecting them, discard frame. 533 */ 534 ns = nr = 0; 535 L2TP_SKB_CB(skb)->has_seq = 0; 536 if (tunnel->version == L2TP_HDR_VER_2) { 537 if (hdrflags & L2TP_HDRFLAG_S) { 538 ns = ntohs(*(__be16 *) ptr); 539 ptr += 2; 540 nr = ntohs(*(__be16 *) ptr); 541 ptr += 2; 542 543 /* Store L2TP info in the skb */ 544 L2TP_SKB_CB(skb)->ns = ns; 545 L2TP_SKB_CB(skb)->has_seq = 1; 546 547 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 548 "%s: recv data ns=%u, nr=%u, session nr=%u\n", 549 session->name, ns, nr, session->nr); 550 } 551 } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 552 u32 l2h = ntohl(*(__be32 *) ptr); 553 554 if (l2h & 0x40000000) { 555 ns = l2h & 0x00ffffff; 556 557 /* Store L2TP info in the skb */ 558 L2TP_SKB_CB(skb)->ns = ns; 559 L2TP_SKB_CB(skb)->has_seq = 1; 560 561 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 562 "%s: recv data ns=%u, session nr=%u\n", 563 session->name, ns, session->nr); 564 } 565 } 566 567 /* Advance past L2-specific header, if present */ 568 ptr += session->l2specific_len; 569 570 if (L2TP_SKB_CB(skb)->has_seq) { 571 /* Received a packet with sequence numbers. If we're the LNS, 572 * check if we sre sending sequence numbers and if not, 573 * configure it so. 574 */ 575 if ((!session->lns_mode) && (!session->send_seq)) { 576 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, 577 "%s: requested to enable seq numbers by LNS\n", 578 session->name); 579 session->send_seq = -1; 580 l2tp_session_set_header_len(session, tunnel->version); 581 } 582 } else { 583 /* No sequence numbers. 584 * If user has configured mandatory sequence numbers, discard. 585 */ 586 if (session->recv_seq) { 587 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, 588 "%s: recv data has no seq numbers when required. " 589 "Discarding\n", session->name); 590 session->stats.rx_seq_discards++; 591 goto discard; 592 } 593 594 /* If we're the LAC and we're sending sequence numbers, the 595 * LNS has requested that we no longer send sequence numbers. 596 * If we're the LNS and we're sending sequence numbers, the 597 * LAC is broken. Discard the frame. 598 */ 599 if ((!session->lns_mode) && (session->send_seq)) { 600 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, 601 "%s: requested to disable seq numbers by LNS\n", 602 session->name); 603 session->send_seq = 0; 604 l2tp_session_set_header_len(session, tunnel->version); 605 } else if (session->send_seq) { 606 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, 607 "%s: recv data has no seq numbers when required. " 608 "Discarding\n", session->name); 609 session->stats.rx_seq_discards++; 610 goto discard; 611 } 612 } 613 614 /* Session data offset is handled differently for L2TPv2 and 615 * L2TPv3. For L2TPv2, there is an optional 16-bit value in 616 * the header. For L2TPv3, the offset is negotiated using AVPs 617 * in the session setup control protocol. 618 */ 619 if (tunnel->version == L2TP_HDR_VER_2) { 620 /* If offset bit set, skip it. */ 621 if (hdrflags & L2TP_HDRFLAG_O) { 622 offset = ntohs(*(__be16 *)ptr); 623 ptr += 2 + offset; 624 } 625 } else 626 ptr += session->offset; 627 628 offset = ptr - optr; 629 if (!pskb_may_pull(skb, offset)) 630 goto discard; 631 632 __skb_pull(skb, offset); 633 634 /* If caller wants to process the payload before we queue the 635 * packet, do so now. 636 */ 637 if (payload_hook) 638 if ((*payload_hook)(skb)) 639 goto discard; 640 641 /* Prepare skb for adding to the session's reorder_q. Hold 642 * packets for max reorder_timeout or 1 second if not 643 * reordering. 644 */ 645 L2TP_SKB_CB(skb)->length = length; 646 L2TP_SKB_CB(skb)->expires = jiffies + 647 (session->reorder_timeout ? session->reorder_timeout : HZ); 648 649 /* Add packet to the session's receive queue. Reordering is done here, if 650 * enabled. Saved L2TP protocol info is stored in skb->sb[]. 651 */ 652 if (L2TP_SKB_CB(skb)->has_seq) { 653 if (session->reorder_timeout != 0) { 654 /* Packet reordering enabled. Add skb to session's 655 * reorder queue, in order of ns. 656 */ 657 l2tp_recv_queue_skb(session, skb); 658 } else { 659 /* Packet reordering disabled. Discard out-of-sequence 660 * packets 661 */ 662 if (L2TP_SKB_CB(skb)->ns != session->nr) { 663 session->stats.rx_seq_discards++; 664 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 665 "%s: oos pkt %u len %d discarded, " 666 "waiting for %u, reorder_q_len=%d\n", 667 session->name, L2TP_SKB_CB(skb)->ns, 668 L2TP_SKB_CB(skb)->length, session->nr, 669 skb_queue_len(&session->reorder_q)); 670 goto discard; 671 } 672 skb_queue_tail(&session->reorder_q, skb); 673 } 674 } else { 675 /* No sequence numbers. Add the skb to the tail of the 676 * reorder queue. This ensures that it will be 677 * delivered after all previous sequenced skbs. 678 */ 679 skb_queue_tail(&session->reorder_q, skb); 680 } 681 682 /* Try to dequeue as many skbs from reorder_q as we can. */ 683 l2tp_recv_dequeue(session); 684 685 l2tp_session_dec_refcount(session); 686 687 return; 688 689discard: 690 session->stats.rx_errors++; 691 kfree_skb(skb); 692 693 if (session->deref) 694 (*session->deref)(session); 695 696 l2tp_session_dec_refcount(session); 697} 698EXPORT_SYMBOL(l2tp_recv_common); 699 700/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame 701 * here. The skb is not on a list when we get here. 702 * Returns 0 if the packet was a data packet and was successfully passed on. 703 * Returns 1 if the packet was not a good data packet and could not be 704 * forwarded. All such packets are passed up to userspace to deal with. 705 */ 706int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, 707 int (*payload_hook)(struct sk_buff *skb)) 708{ 709 struct l2tp_session *session = NULL; 710 unsigned char *ptr, *optr; 711 u16 hdrflags; 712 u32 tunnel_id, session_id; 713 int offset; 714 u16 version; 715 int length; 716 717 if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) 718 goto discard_bad_csum; 719 720 /* UDP always verifies the packet length. */ 721 __skb_pull(skb, sizeof(struct udphdr)); 722 723 /* Short packet? */ 724 if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { 725 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 726 "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); 727 goto error; 728 } 729 730 /* Point to L2TP header */ 731 optr = ptr = skb->data; 732 733 /* Trace packet contents, if enabled */ 734 if (tunnel->debug & L2TP_MSG_DATA) { 735 length = min(32u, skb->len); 736 if (!pskb_may_pull(skb, length)) 737 goto error; 738 739 printk(KERN_DEBUG "%s: recv: ", tunnel->name); 740 741 offset = 0; 742 do { 743 printk(" %02X", ptr[offset]); 744 } while (++offset < length); 745 746 printk("\n"); 747 } 748 749 /* Get L2TP header flags */ 750 hdrflags = ntohs(*(__be16 *) ptr); 751 752 /* Check protocol version */ 753 version = hdrflags & L2TP_HDR_VER_MASK; 754 if (version != tunnel->version) { 755 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 756 "%s: recv protocol version mismatch: got %d expected %d\n", 757 tunnel->name, version, tunnel->version); 758 goto error; 759 } 760 761 /* Get length of L2TP packet */ 762 length = skb->len; 763 764 /* If type is control packet, it is handled by userspace. */ 765 if (hdrflags & L2TP_HDRFLAG_T) { 766 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, 767 "%s: recv control packet, len=%d\n", tunnel->name, length); 768 goto error; 769 } 770 771 /* Skip flags */ 772 ptr += 2; 773 774 if (tunnel->version == L2TP_HDR_VER_2) { 775 /* If length is present, skip it */ 776 if (hdrflags & L2TP_HDRFLAG_L) 777 ptr += 2; 778 779 /* Extract tunnel and session ID */ 780 tunnel_id = ntohs(*(__be16 *) ptr); 781 ptr += 2; 782 session_id = ntohs(*(__be16 *) ptr); 783 ptr += 2; 784 } else { 785 ptr += 2; /* skip reserved bits */ 786 tunnel_id = tunnel->tunnel_id; 787 session_id = ntohl(*(__be32 *) ptr); 788 ptr += 4; 789 } 790 791 /* Find the session context */ 792 session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id); 793 if (!session || !session->recv_skb) { 794 /* Not found? Pass to userspace to deal with */ 795 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 796 "%s: no session found (%u/%u). Passing up.\n", 797 tunnel->name, tunnel_id, session_id); 798 goto error; 799 } 800 801 l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); 802 803 return 0; 804 805discard_bad_csum: 806 LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); 807 UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); 808 tunnel->stats.rx_errors++; 809 kfree_skb(skb); 810 811 return 0; 812 813error: 814 /* Put UDP header back */ 815 __skb_push(skb, sizeof(struct udphdr)); 816 817 return 1; 818} 819EXPORT_SYMBOL_GPL(l2tp_udp_recv_core); 820 821/* UDP encapsulation receive handler. See net/ipv4/udp.c. 822 * Return codes: 823 * 0 : success. 824 * <0: error 825 * >0: skb should be passed up to userspace as UDP. 826 */ 827int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 828{ 829 struct l2tp_tunnel *tunnel; 830 831 tunnel = l2tp_sock_to_tunnel(sk); 832 if (tunnel == NULL) 833 goto pass_up; 834 835 PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, 836 "%s: received %d bytes\n", tunnel->name, skb->len); 837 838 if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) 839 goto pass_up_put; 840 841 sock_put(sk); 842 return 0; 843 844pass_up_put: 845 sock_put(sk); 846pass_up: 847 return 1; 848} 849EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); 850 851/************************************************************************ 852 * Transmit handling 853 ***********************************************************************/ 854 855/* Build an L2TP header for the session into the buffer provided. 856 */ 857static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) 858{ 859 struct l2tp_tunnel *tunnel = session->tunnel; 860 __be16 *bufp = buf; 861 __be16 *optr = buf; 862 u16 flags = L2TP_HDR_VER_2; 863 u32 tunnel_id = tunnel->peer_tunnel_id; 864 u32 session_id = session->peer_session_id; 865 866 if (session->send_seq) 867 flags |= L2TP_HDRFLAG_S; 868 869 /* Setup L2TP header. */ 870 *bufp++ = htons(flags); 871 *bufp++ = htons(tunnel_id); 872 *bufp++ = htons(session_id); 873 if (session->send_seq) { 874 *bufp++ = htons(session->ns); 875 *bufp++ = 0; 876 session->ns++; 877 session->ns &= 0xffff; 878 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 879 "%s: updated ns to %u\n", session->name, session->ns); 880 } 881 882 return bufp - optr; 883} 884 885static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 886{ 887 struct l2tp_tunnel *tunnel = session->tunnel; 888 char *bufp = buf; 889 char *optr = bufp; 890 891 /* Setup L2TP header. The header differs slightly for UDP and 892 * IP encapsulations. For UDP, there is 4 bytes of flags. 893 */ 894 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 895 u16 flags = L2TP_HDR_VER_3; 896 *((__be16 *) bufp) = htons(flags); 897 bufp += 2; 898 *((__be16 *) bufp) = 0; 899 bufp += 2; 900 } 901 902 *((__be32 *) bufp) = htonl(session->peer_session_id); 903 bufp += 4; 904 if (session->cookie_len) { 905 memcpy(bufp, &session->cookie[0], session->cookie_len); 906 bufp += session->cookie_len; 907 } 908 if (session->l2specific_len) { 909 if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 910 u32 l2h = 0; 911 if (session->send_seq) { 912 l2h = 0x40000000 | session->ns; 913 session->ns++; 914 session->ns &= 0xffffff; 915 PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 916 "%s: updated ns to %u\n", session->name, session->ns); 917 } 918 919 *((__be32 *) bufp) = htonl(l2h); 920 } 921 bufp += session->l2specific_len; 922 } 923 if (session->offset) 924 bufp += session->offset; 925 926 return bufp - optr; 927} 928 929int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len) 930{ 931 struct l2tp_tunnel *tunnel = session->tunnel; 932 unsigned int len = skb->len; 933 int error; 934 935 /* Debug */ 936 if (session->send_seq) 937 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, 938 "%s: send %Zd bytes, ns=%u\n", session->name, 939 data_len, session->ns - 1); 940 else 941 PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, 942 "%s: send %Zd bytes\n", session->name, data_len); 943 944 if (session->debug & L2TP_MSG_DATA) { 945 int i; 946 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 947 unsigned char *datap = skb->data + uhlen; 948 949 printk(KERN_DEBUG "%s: xmit:", session->name); 950 for (i = 0; i < (len - uhlen); i++) { 951 printk(" %02X", *datap++); 952 if (i == 31) { 953 printk(" ..."); 954 break; 955 } 956 } 957 printk("\n"); 958 } 959 960 /* Queue the packet to IP for output */ 961 skb->local_df = 1; 962 error = ip_queue_xmit(skb); 963 964 /* Update stats */ 965 if (error >= 0) { 966 tunnel->stats.tx_packets++; 967 tunnel->stats.tx_bytes += len; 968 session->stats.tx_packets++; 969 session->stats.tx_bytes += len; 970 } else { 971 tunnel->stats.tx_errors++; 972 session->stats.tx_errors++; 973 } 974 975 return 0; 976} 977EXPORT_SYMBOL_GPL(l2tp_xmit_core); 978 979/* Automatically called when the skb is freed. 980 */ 981static void l2tp_sock_wfree(struct sk_buff *skb) 982{ 983 sock_put(skb->sk); 984} 985 986/* For data skbs that we transmit, we associate with the tunnel socket 987 * but don't do accounting. 988 */ 989static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) 990{ 991 sock_hold(sk); 992 skb->sk = sk; 993 skb->destructor = l2tp_sock_wfree; 994} 995 996/* If caller requires the skb to have a ppp header, the header must be 997 * inserted in the skb data before calling this function. 998 */ 999int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) 1000{ 1001 int data_len = skb->len; 1002 struct l2tp_tunnel *tunnel = session->tunnel; 1003 struct sock *sk = tunnel->sock; 1004 struct udphdr *uh; 1005 struct inet_sock *inet; 1006 __wsum csum; 1007 int old_headroom; 1008 int new_headroom; 1009 int headroom; 1010 int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 1011 int udp_len; 1012 1013 /* Check that there's enough headroom in the skb to insert IP, 1014 * UDP and L2TP headers. If not enough, expand it to 1015 * make room. Adjust truesize. 1016 */ 1017 headroom = NET_SKB_PAD + sizeof(struct iphdr) + 1018 uhlen + hdr_len; 1019 old_headroom = skb_headroom(skb); 1020 if (skb_cow_head(skb, headroom)) 1021 goto abort; 1022 1023 new_headroom = skb_headroom(skb); 1024 skb_orphan(skb); 1025 skb->truesize += new_headroom - old_headroom; 1026 1027 /* Setup L2TP header */ 1028 session->build_header(session, __skb_push(skb, hdr_len)); 1029 1030 /* Reset skb netfilter state */ 1031 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 1032 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 1033 IPSKB_REROUTED); 1034 nf_reset(skb); 1035 1036 /* Get routing info from the tunnel socket */ 1037 skb_dst_drop(skb); 1038 skb_dst_set(skb, dst_clone(__sk_dst_get(sk))); 1039 1040 switch (tunnel->encap) { 1041 case L2TP_ENCAPTYPE_UDP: 1042 /* Setup UDP header */ 1043 inet = inet_sk(sk); 1044 __skb_push(skb, sizeof(*uh)); 1045 skb_reset_transport_header(skb); 1046 uh = udp_hdr(skb); 1047 uh->source = inet->inet_sport; 1048 uh->dest = inet->inet_dport; 1049 udp_len = uhlen + hdr_len + data_len; 1050 uh->len = htons(udp_len); 1051 uh->check = 0; 1052 1053 /* Calculate UDP checksum if configured to do so */ 1054 if (sk->sk_no_check == UDP_CSUM_NOXMIT) 1055 skb->ip_summed = CHECKSUM_NONE; 1056 else if ((skb_dst(skb) && skb_dst(skb)->dev) && 1057 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { 1058 skb->ip_summed = CHECKSUM_COMPLETE; 1059 csum = skb_checksum(skb, 0, udp_len, 0); 1060 uh->check = csum_tcpudp_magic(inet->inet_saddr, 1061 inet->inet_daddr, 1062 udp_len, IPPROTO_UDP, csum); 1063 if (uh->check == 0) 1064 uh->check = CSUM_MANGLED_0; 1065 } else { 1066 skb->ip_summed = CHECKSUM_PARTIAL; 1067 skb->csum_start = skb_transport_header(skb) - skb->head; 1068 skb->csum_offset = offsetof(struct udphdr, check); 1069 uh->check = ~csum_tcpudp_magic(inet->inet_saddr, 1070 inet->inet_daddr, 1071 udp_len, IPPROTO_UDP, 0); 1072 } 1073 break; 1074 1075 case L2TP_ENCAPTYPE_IP: 1076 break; 1077 } 1078 1079 l2tp_skb_set_owner_w(skb, sk); 1080 1081 l2tp_xmit_core(session, skb, data_len); 1082 1083abort: 1084 return 0; 1085} 1086EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 1087 1088/***************************************************************************** 1089 * Tinnel and session create/destroy. 1090 *****************************************************************************/ 1091 1092/* Tunnel socket destruct hook. 1093 * The tunnel context is deleted only when all session sockets have been 1094 * closed. 1095 */ 1096void l2tp_tunnel_destruct(struct sock *sk) 1097{ 1098 struct l2tp_tunnel *tunnel; 1099 1100 tunnel = sk->sk_user_data; 1101 if (tunnel == NULL) 1102 goto end; 1103 1104 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1105 "%s: closing...\n", tunnel->name); 1106 1107 /* Close all sessions */ 1108 l2tp_tunnel_closeall(tunnel); 1109 1110 switch (tunnel->encap) { 1111 case L2TP_ENCAPTYPE_UDP: 1112 /* No longer an encapsulation socket. See net/ipv4/udp.c */ 1113 (udp_sk(sk))->encap_type = 0; 1114 (udp_sk(sk))->encap_rcv = NULL; 1115 break; 1116 case L2TP_ENCAPTYPE_IP: 1117 break; 1118 } 1119 1120 /* Remove hooks into tunnel socket */ 1121 tunnel->sock = NULL; 1122 sk->sk_destruct = tunnel->old_sk_destruct; 1123 sk->sk_user_data = NULL; 1124 1125 /* Call the original destructor */ 1126 if (sk->sk_destruct) 1127 (*sk->sk_destruct)(sk); 1128 1129 /* We're finished with the socket */ 1130 l2tp_tunnel_dec_refcount(tunnel); 1131 1132end: 1133 return; 1134} 1135EXPORT_SYMBOL(l2tp_tunnel_destruct); 1136 1137/* When the tunnel is closed, all the attached sessions need to go too. 1138 */ 1139void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 1140{ 1141 int hash; 1142 struct hlist_node *walk; 1143 struct hlist_node *tmp; 1144 struct l2tp_session *session; 1145 1146 BUG_ON(tunnel == NULL); 1147 1148 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1149 "%s: closing all sessions...\n", tunnel->name); 1150 1151 write_lock_bh(&tunnel->hlist_lock); 1152 for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 1153again: 1154 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { 1155 session = hlist_entry(walk, struct l2tp_session, hlist); 1156 1157 PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO, 1158 "%s: closing session\n", session->name); 1159 1160 hlist_del_init(&session->hlist); 1161 1162 /* Since we should hold the sock lock while 1163 * doing any unbinding, we need to release the 1164 * lock we're holding before taking that lock. 1165 * Hold a reference to the sock so it doesn't 1166 * disappear as we're jumping between locks. 1167 */ 1168 if (session->ref != NULL) 1169 (*session->ref)(session); 1170 1171 write_unlock_bh(&tunnel->hlist_lock); 1172 1173 if (tunnel->version != L2TP_HDR_VER_2) { 1174 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1175 1176 spin_lock_bh(&pn->l2tp_session_hlist_lock); 1177 hlist_del_init_rcu(&session->global_hlist); 1178 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1179 synchronize_rcu(); 1180 } 1181 1182 if (session->session_close != NULL) 1183 (*session->session_close)(session); 1184 1185 if (session->deref != NULL) 1186 (*session->deref)(session); 1187 1188 write_lock_bh(&tunnel->hlist_lock); 1189 1190 /* Now restart from the beginning of this hash 1191 * chain. We always remove a session from the 1192 * list so we are guaranteed to make forward 1193 * progress. 1194 */ 1195 goto again; 1196 } 1197 } 1198 write_unlock_bh(&tunnel->hlist_lock); 1199} 1200EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); 1201 1202/* Really kill the tunnel. 1203 * Come here only when all sessions have been cleared from the tunnel. 1204 */ 1205void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) 1206{ 1207 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1208 1209 BUG_ON(atomic_read(&tunnel->ref_count) != 0); 1210 BUG_ON(tunnel->sock != NULL); 1211 1212 PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1213 "%s: free...\n", tunnel->name); 1214 1215 /* Remove from tunnel list */ 1216 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1217 list_del_rcu(&tunnel->list); 1218 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1219 synchronize_rcu(); 1220 1221 atomic_dec(&l2tp_tunnel_count); 1222 kfree(tunnel); 1223 1224#if defined(CTFPOOL) && defined(CTF_L2TP) 1225 osl_ctfpool_direction(0); 1226#endif 1227} 1228EXPORT_SYMBOL_GPL(l2tp_tunnel_free); 1229 1230/* Create a socket for the tunnel, if one isn't set up by 1231 * userspace. This is used for static tunnels where there is no 1232 * managing L2TP daemon. 1233 */ 1234static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) 1235{ 1236 int err = -EINVAL; 1237 struct sockaddr_in udp_addr; 1238 struct sockaddr_l2tpip ip_addr; 1239 struct socket *sock = NULL; 1240 1241 switch (cfg->encap) { 1242 case L2TP_ENCAPTYPE_UDP: 1243 err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp); 1244 if (err < 0) 1245 goto out; 1246 1247 sock = *sockp; 1248 1249 memset(&udp_addr, 0, sizeof(udp_addr)); 1250 udp_addr.sin_family = AF_INET; 1251 udp_addr.sin_addr = cfg->local_ip; 1252 udp_addr.sin_port = htons(cfg->local_udp_port); 1253 err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr)); 1254 if (err < 0) 1255 goto out; 1256 1257 udp_addr.sin_family = AF_INET; 1258 udp_addr.sin_addr = cfg->peer_ip; 1259 udp_addr.sin_port = htons(cfg->peer_udp_port); 1260 err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0); 1261 if (err < 0) 1262 goto out; 1263 1264 if (!cfg->use_udp_checksums) 1265 sock->sk->sk_no_check = UDP_CSUM_NOXMIT; 1266 1267 break; 1268 1269 case L2TP_ENCAPTYPE_IP: 1270 err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp); 1271 if (err < 0) 1272 goto out; 1273 1274 sock = *sockp; 1275 1276 memset(&ip_addr, 0, sizeof(ip_addr)); 1277 ip_addr.l2tp_family = AF_INET; 1278 ip_addr.l2tp_addr = cfg->local_ip; 1279 ip_addr.l2tp_conn_id = tunnel_id; 1280 err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr)); 1281 if (err < 0) 1282 goto out; 1283 1284 ip_addr.l2tp_family = AF_INET; 1285 ip_addr.l2tp_addr = cfg->peer_ip; 1286 ip_addr.l2tp_conn_id = peer_tunnel_id; 1287 err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0); 1288 if (err < 0) 1289 goto out; 1290 1291 break; 1292 1293 default: 1294 goto out; 1295 } 1296 1297out: 1298 if ((err < 0) && sock) { 1299 sock_release(sock); 1300 *sockp = NULL; 1301 } 1302 1303 return err; 1304} 1305 1306int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) 1307{ 1308 struct l2tp_tunnel *tunnel = NULL; 1309 int err; 1310 struct socket *sock = NULL; 1311 struct sock *sk = NULL; 1312 struct l2tp_net *pn; 1313 enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; 1314 1315 /* Get the tunnel socket from the fd, which was opened by 1316 * the userspace L2TP daemon. If not specified, create a 1317 * kernel socket. 1318 */ 1319 if (fd < 0) { 1320 err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock); 1321 if (err < 0) 1322 goto err; 1323 } else { 1324 err = -EBADF; 1325 sock = sockfd_lookup(fd, &err); 1326 if (!sock) { 1327 printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", 1328 tunnel_id, fd, err); 1329 goto err; 1330 } 1331 } 1332 1333 sk = sock->sk; 1334 1335 if (cfg != NULL) 1336 encap = cfg->encap; 1337 1338 /* Quick sanity checks */ 1339 switch (encap) { 1340 case L2TP_ENCAPTYPE_UDP: 1341 err = -EPROTONOSUPPORT; 1342 if (sk->sk_protocol != IPPROTO_UDP) { 1343 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1344 tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); 1345 goto err; 1346 } 1347 break; 1348 case L2TP_ENCAPTYPE_IP: 1349 err = -EPROTONOSUPPORT; 1350 if (sk->sk_protocol != IPPROTO_L2TP) { 1351 printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1352 tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); 1353 goto err; 1354 } 1355 break; 1356 } 1357 1358 /* Check if this socket has already been prepped */ 1359 tunnel = (struct l2tp_tunnel *)sk->sk_user_data; 1360 if (tunnel != NULL) { 1361 /* This socket has already been prepped */ 1362 err = -EBUSY; 1363 goto err; 1364 } 1365 1366 tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); 1367 if (tunnel == NULL) { 1368 err = -ENOMEM; 1369 goto err; 1370 } 1371 1372 tunnel->version = version; 1373 tunnel->tunnel_id = tunnel_id; 1374 tunnel->peer_tunnel_id = peer_tunnel_id; 1375 tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; 1376 1377 tunnel->magic = L2TP_TUNNEL_MAGIC; 1378 sprintf(&tunnel->name[0], "tunl %u", tunnel_id); 1379 rwlock_init(&tunnel->hlist_lock); 1380 1381 /* The net we belong to */ 1382 tunnel->l2tp_net = net; 1383 pn = l2tp_pernet(net); 1384 1385 if (cfg != NULL) 1386 tunnel->debug = cfg->debug; 1387 1388 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 1389 tunnel->encap = encap; 1390 if (encap == L2TP_ENCAPTYPE_UDP) { 1391 /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 1392 udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; 1393 udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; 1394 } 1395 1396 sk->sk_user_data = tunnel; 1397 1398 /* Hook on the tunnel socket destructor so that we can cleanup 1399 * if the tunnel socket goes away. 1400 */ 1401 tunnel->old_sk_destruct = sk->sk_destruct; 1402 sk->sk_destruct = &l2tp_tunnel_destruct; 1403 tunnel->sock = sk; 1404 sk->sk_allocation = GFP_ATOMIC; 1405 1406 /* Add tunnel to our list */ 1407 INIT_LIST_HEAD(&tunnel->list); 1408 spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1409 list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); 1410 spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1411 synchronize_rcu(); 1412 atomic_inc(&l2tp_tunnel_count); 1413 1414 /* Bump the reference count. The tunnel context is deleted 1415 * only when this drops to zero. 1416 */ 1417 l2tp_tunnel_inc_refcount(tunnel); 1418 1419#if defined(CTFPOOL) && defined(CTF_L2TP) 1420 osl_ctfpool_direction(1); 1421#endif 1422 1423 err = 0; 1424err: 1425 if (tunnelp) 1426 *tunnelp = tunnel; 1427 1428 /* If tunnel's socket was created by the kernel, it doesn't 1429 * have a file. 1430 */ 1431 if (sock && sock->file) 1432 sockfd_put(sock); 1433 1434 return err; 1435} 1436EXPORT_SYMBOL_GPL(l2tp_tunnel_create); 1437 1438/* This function is used by the netlink TUNNEL_DELETE command. 1439 */ 1440int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) 1441{ 1442 int err = 0; 1443 struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL; 1444 1445 /* Force the tunnel socket to close. This will eventually 1446 * cause the tunnel to be deleted via the normal socket close 1447 * mechanisms when userspace closes the tunnel socket. 1448 */ 1449 if (sock != NULL) { 1450 err = inet_shutdown(sock, 2); 1451 1452 /* If the tunnel's socket was created by the kernel, 1453 * close the socket here since the socket was not 1454 * created by userspace. 1455 */ 1456 if (sock->file == NULL) 1457 err = inet_release(sock); 1458 } 1459 1460 return err; 1461} 1462EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); 1463 1464/* Really kill the session. 1465 */ 1466void l2tp_session_free(struct l2tp_session *session) 1467{ 1468 struct l2tp_tunnel *tunnel; 1469 1470 BUG_ON(atomic_read(&session->ref_count) != 0); 1471 1472 tunnel = session->tunnel; 1473 if (tunnel != NULL) { 1474 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 1475 1476 /* Delete the session from the hash */ 1477 write_lock_bh(&tunnel->hlist_lock); 1478 hlist_del_init(&session->hlist); 1479 write_unlock_bh(&tunnel->hlist_lock); 1480 1481 /* Unlink from the global hash if not L2TPv2 */ 1482 if (tunnel->version != L2TP_HDR_VER_2) { 1483 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1484 1485 spin_lock_bh(&pn->l2tp_session_hlist_lock); 1486 hlist_del_init_rcu(&session->global_hlist); 1487 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1488 synchronize_rcu(); 1489 } 1490 1491 if (session->session_id != 0) 1492 atomic_dec(&l2tp_session_count); 1493 1494 sock_put(tunnel->sock); 1495 1496 /* This will delete the tunnel context if this 1497 * is the last session on the tunnel. 1498 */ 1499 session->tunnel = NULL; 1500 l2tp_tunnel_dec_refcount(tunnel); 1501 } 1502 1503 kfree(session); 1504 1505 return; 1506} 1507EXPORT_SYMBOL_GPL(l2tp_session_free); 1508 1509/* This function is used by the netlink SESSION_DELETE command and by 1510 pseudowire modules. 1511 */ 1512int l2tp_session_delete(struct l2tp_session *session) 1513{ 1514 if (session->session_close != NULL) 1515 (*session->session_close)(session); 1516 1517 l2tp_session_dec_refcount(session); 1518 1519 return 0; 1520} 1521EXPORT_SYMBOL_GPL(l2tp_session_delete); 1522 1523 1524/* We come here whenever a session's send_seq, cookie_len or 1525 * l2specific_len parameters are set. 1526 */ 1527void l2tp_session_set_header_len(struct l2tp_session *session, int version) 1528{ 1529 if (version == L2TP_HDR_VER_2) { 1530 session->hdr_len = 6; 1531 if (session->send_seq) 1532 session->hdr_len += 4; 1533 } else { 1534 session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; 1535 if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) 1536 session->hdr_len += 4; 1537 } 1538 1539} 1540EXPORT_SYMBOL_GPL(l2tp_session_set_header_len); 1541 1542struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) 1543{ 1544 struct l2tp_session *session; 1545 1546 session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); 1547 if (session != NULL) { 1548 session->magic = L2TP_SESSION_MAGIC; 1549 session->tunnel = tunnel; 1550 1551 session->session_id = session_id; 1552 session->peer_session_id = peer_session_id; 1553 session->nr = 1; 1554 1555 sprintf(&session->name[0], "sess %u/%u", 1556 tunnel->tunnel_id, session->session_id); 1557 1558 skb_queue_head_init(&session->reorder_q); 1559 1560 INIT_HLIST_NODE(&session->hlist); 1561 INIT_HLIST_NODE(&session->global_hlist); 1562 1563 /* Inherit debug options from tunnel */ 1564 session->debug = tunnel->debug; 1565 1566 if (cfg) { 1567 session->pwtype = cfg->pw_type; 1568 session->debug = cfg->debug; 1569 session->mtu = cfg->mtu; 1570 session->mru = cfg->mru; 1571 session->send_seq = cfg->send_seq; 1572 session->recv_seq = cfg->recv_seq; 1573 session->lns_mode = cfg->lns_mode; 1574 session->reorder_timeout = cfg->reorder_timeout; 1575 session->offset = cfg->offset; 1576 session->l2specific_type = cfg->l2specific_type; 1577 session->l2specific_len = cfg->l2specific_len; 1578 session->cookie_len = cfg->cookie_len; 1579 memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); 1580 session->peer_cookie_len = cfg->peer_cookie_len; 1581 memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); 1582 } 1583 1584 if (tunnel->version == L2TP_HDR_VER_2) 1585 session->build_header = l2tp_build_l2tpv2_header; 1586 else 1587 session->build_header = l2tp_build_l2tpv3_header; 1588 1589 l2tp_session_set_header_len(session, tunnel->version); 1590 1591 /* Bump the reference count. The session context is deleted 1592 * only when this drops to zero. 1593 */ 1594 l2tp_session_inc_refcount(session); 1595 l2tp_tunnel_inc_refcount(tunnel); 1596 1597 /* Ensure tunnel socket isn't deleted */ 1598 sock_hold(tunnel->sock); 1599 1600 /* Add session to the tunnel's hash list */ 1601 write_lock_bh(&tunnel->hlist_lock); 1602 hlist_add_head(&session->hlist, 1603 l2tp_session_id_hash(tunnel, session_id)); 1604 write_unlock_bh(&tunnel->hlist_lock); 1605 1606 /* And to the global session list if L2TPv3 */ 1607 if (tunnel->version != L2TP_HDR_VER_2) { 1608 struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1609 1610 spin_lock_bh(&pn->l2tp_session_hlist_lock); 1611 hlist_add_head_rcu(&session->global_hlist, 1612 l2tp_session_id_hash_2(pn, session_id)); 1613 spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1614 synchronize_rcu(); 1615 } 1616 1617 /* Ignore management session in session count value */ 1618 if (session->session_id != 0) 1619 atomic_inc(&l2tp_session_count); 1620 } 1621 1622 return session; 1623} 1624EXPORT_SYMBOL_GPL(l2tp_session_create); 1625 1626/***************************************************************************** 1627 * Init and cleanup 1628 *****************************************************************************/ 1629 1630static __net_init int l2tp_init_net(struct net *net) 1631{ 1632 struct l2tp_net *pn = net_generic(net, l2tp_net_id); 1633 int hash; 1634 1635 INIT_LIST_HEAD(&pn->l2tp_tunnel_list); 1636 spin_lock_init(&pn->l2tp_tunnel_list_lock); 1637 1638 for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) 1639 INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); 1640 1641 spin_lock_init(&pn->l2tp_session_hlist_lock); 1642 1643 return 0; 1644} 1645 1646static struct pernet_operations l2tp_net_ops = { 1647 .init = l2tp_init_net, 1648 .id = &l2tp_net_id, 1649 .size = sizeof(struct l2tp_net), 1650}; 1651 1652static int __init l2tp_init(void) 1653{ 1654 int rc = 0; 1655 1656 rc = register_pernet_device(&l2tp_net_ops); 1657 if (rc) 1658 goto out; 1659 1660 printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); 1661 1662out: 1663 return rc; 1664} 1665 1666static void __exit l2tp_exit(void) 1667{ 1668 unregister_pernet_device(&l2tp_net_ops); 1669} 1670 1671module_init(l2tp_init); 1672module_exit(l2tp_exit); 1673 1674MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 1675MODULE_DESCRIPTION("L2TP core"); 1676MODULE_LICENSE("GPL"); 1677MODULE_VERSION(L2TP_DRV_VERSION); 1678