James Chapman | fd558d1 | 2010-04-02 06:18:33 +0000 | [diff] [blame^] | 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/uaccess.h> |
| 25 | |
| 26 | #include <linux/kernel.h> |
| 27 | #include <linux/spinlock.h> |
| 28 | #include <linux/kthread.h> |
| 29 | #include <linux/sched.h> |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/errno.h> |
| 32 | #include <linux/jiffies.h> |
| 33 | |
| 34 | #include <linux/netdevice.h> |
| 35 | #include <linux/net.h> |
| 36 | #include <linux/inetdevice.h> |
| 37 | #include <linux/skbuff.h> |
| 38 | #include <linux/init.h> |
| 39 | #include <linux/ip.h> |
| 40 | #include <linux/udp.h> |
| 41 | #include <linux/hash.h> |
| 42 | #include <linux/sort.h> |
| 43 | #include <linux/file.h> |
| 44 | #include <linux/nsproxy.h> |
| 45 | #include <net/net_namespace.h> |
| 46 | #include <net/netns/generic.h> |
| 47 | #include <net/dst.h> |
| 48 | #include <net/ip.h> |
| 49 | #include <net/udp.h> |
| 50 | #include <net/xfrm.h> |
| 51 | |
| 52 | #include <asm/byteorder.h> |
| 53 | #include <asm/atomic.h> |
| 54 | |
| 55 | #include "l2tp_core.h" |
| 56 | |
| 57 | #define L2TP_DRV_VERSION "V2.0" |
| 58 | |
| 59 | /* L2TP header constants */ |
| 60 | #define L2TP_HDRFLAG_T 0x8000 |
| 61 | #define L2TP_HDRFLAG_L 0x4000 |
| 62 | #define L2TP_HDRFLAG_S 0x0800 |
| 63 | #define L2TP_HDRFLAG_O 0x0200 |
| 64 | #define L2TP_HDRFLAG_P 0x0100 |
| 65 | |
| 66 | #define L2TP_HDR_VER_MASK 0x000F |
| 67 | #define L2TP_HDR_VER_2 0x0002 |
| 68 | |
| 69 | /* L2TPv3 default L2-specific sublayer */ |
| 70 | #define L2TP_SLFLAG_S 0x40000000 |
| 71 | #define L2TP_SL_SEQ_MASK 0x00ffffff |
| 72 | |
| 73 | #define L2TP_HDR_SIZE_SEQ 10 |
| 74 | #define L2TP_HDR_SIZE_NOSEQ 6 |
| 75 | |
| 76 | /* Default trace flags */ |
| 77 | #define L2TP_DEFAULT_DEBUG_FLAGS 0 |
| 78 | |
| 79 | #define PRINTK(_mask, _type, _lvl, _fmt, args...) \ |
| 80 | do { \ |
| 81 | if ((_mask) & (_type)) \ |
| 82 | printk(_lvl "L2TP: " _fmt, ##args); \ |
| 83 | } while (0) |
| 84 | |
| 85 | /* Private data stored for received packets in the skb. |
| 86 | */ |
| 87 | struct l2tp_skb_cb { |
| 88 | u16 ns; |
| 89 | u16 has_seq; |
| 90 | u16 length; |
| 91 | unsigned long expires; |
| 92 | }; |
| 93 | |
| 94 | #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) |
| 95 | |
| 96 | static atomic_t l2tp_tunnel_count; |
| 97 | static atomic_t l2tp_session_count; |
| 98 | |
| 99 | /* per-net private data for this module */ |
| 100 | static unsigned int l2tp_net_id; |
| 101 | struct l2tp_net { |
| 102 | struct list_head l2tp_tunnel_list; |
| 103 | rwlock_t l2tp_tunnel_list_lock; |
| 104 | }; |
| 105 | |
| 106 | static inline struct l2tp_net *l2tp_pernet(struct net *net) |
| 107 | { |
| 108 | BUG_ON(!net); |
| 109 | |
| 110 | return net_generic(net, l2tp_net_id); |
| 111 | } |
| 112 | |
| 113 | /* Session hash list. |
| 114 | * The session_id SHOULD be random according to RFC2661, but several |
| 115 | * L2TP implementations (Cisco and Microsoft) use incrementing |
| 116 | * session_ids. So we do a real hash on the session_id, rather than a |
| 117 | * simple bitmask. |
| 118 | */ |
| 119 | static inline struct hlist_head * |
| 120 | l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) |
| 121 | { |
| 122 | return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; |
| 123 | } |
| 124 | |
| 125 | /* Lookup a session by id |
| 126 | */ |
| 127 | struct l2tp_session *l2tp_session_find(struct l2tp_tunnel *tunnel, u32 session_id) |
| 128 | { |
| 129 | struct hlist_head *session_list = |
| 130 | l2tp_session_id_hash(tunnel, session_id); |
| 131 | struct l2tp_session *session; |
| 132 | struct hlist_node *walk; |
| 133 | |
| 134 | read_lock_bh(&tunnel->hlist_lock); |
| 135 | hlist_for_each_entry(session, walk, session_list, hlist) { |
| 136 | if (session->session_id == session_id) { |
| 137 | read_unlock_bh(&tunnel->hlist_lock); |
| 138 | return session; |
| 139 | } |
| 140 | } |
| 141 | read_unlock_bh(&tunnel->hlist_lock); |
| 142 | |
| 143 | return NULL; |
| 144 | } |
| 145 | EXPORT_SYMBOL_GPL(l2tp_session_find); |
| 146 | |
| 147 | struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) |
| 148 | { |
| 149 | int hash; |
| 150 | struct hlist_node *walk; |
| 151 | struct l2tp_session *session; |
| 152 | int count = 0; |
| 153 | |
| 154 | read_lock_bh(&tunnel->hlist_lock); |
| 155 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { |
| 156 | hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { |
| 157 | if (++count > nth) { |
| 158 | read_unlock_bh(&tunnel->hlist_lock); |
| 159 | return session; |
| 160 | } |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | read_unlock_bh(&tunnel->hlist_lock); |
| 165 | |
| 166 | return NULL; |
| 167 | } |
| 168 | EXPORT_SYMBOL_GPL(l2tp_session_find_nth); |
| 169 | |
| 170 | /* Lookup a tunnel by id |
| 171 | */ |
| 172 | struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) |
| 173 | { |
| 174 | struct l2tp_tunnel *tunnel; |
| 175 | struct l2tp_net *pn = l2tp_pernet(net); |
| 176 | |
| 177 | read_lock_bh(&pn->l2tp_tunnel_list_lock); |
| 178 | list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) { |
| 179 | if (tunnel->tunnel_id == tunnel_id) { |
| 180 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 181 | return tunnel; |
| 182 | } |
| 183 | } |
| 184 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 185 | |
| 186 | return NULL; |
| 187 | } |
| 188 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find); |
| 189 | |
| 190 | struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) |
| 191 | { |
| 192 | struct l2tp_net *pn = l2tp_pernet(net); |
| 193 | struct l2tp_tunnel *tunnel; |
| 194 | int count = 0; |
| 195 | |
| 196 | read_lock_bh(&pn->l2tp_tunnel_list_lock); |
| 197 | list_for_each_entry(tunnel, &pn->l2tp_tunnel_list, list) { |
| 198 | if (++count > nth) { |
| 199 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 200 | return tunnel; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | read_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 205 | |
| 206 | return NULL; |
| 207 | } |
| 208 | EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); |
| 209 | |
| 210 | /***************************************************************************** |
| 211 | * Receive data handling |
| 212 | *****************************************************************************/ |
| 213 | |
| 214 | /* Queue a skb in order. We come here only if the skb has an L2TP sequence |
| 215 | * number. |
| 216 | */ |
| 217 | static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) |
| 218 | { |
| 219 | struct sk_buff *skbp; |
| 220 | struct sk_buff *tmp; |
| 221 | u16 ns = L2TP_SKB_CB(skb)->ns; |
| 222 | |
| 223 | spin_lock_bh(&session->reorder_q.lock); |
| 224 | skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { |
| 225 | if (L2TP_SKB_CB(skbp)->ns > ns) { |
| 226 | __skb_queue_before(&session->reorder_q, skbp, skb); |
| 227 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 228 | "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", |
| 229 | session->name, ns, L2TP_SKB_CB(skbp)->ns, |
| 230 | skb_queue_len(&session->reorder_q)); |
| 231 | session->stats.rx_oos_packets++; |
| 232 | goto out; |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | __skb_queue_tail(&session->reorder_q, skb); |
| 237 | |
| 238 | out: |
| 239 | spin_unlock_bh(&session->reorder_q.lock); |
| 240 | } |
| 241 | |
| 242 | /* Dequeue a single skb. |
| 243 | */ |
| 244 | static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) |
| 245 | { |
| 246 | struct l2tp_tunnel *tunnel = session->tunnel; |
| 247 | int length = L2TP_SKB_CB(skb)->length; |
| 248 | |
| 249 | /* We're about to requeue the skb, so return resources |
| 250 | * to its current owner (a socket receive buffer). |
| 251 | */ |
| 252 | skb_orphan(skb); |
| 253 | |
| 254 | tunnel->stats.rx_packets++; |
| 255 | tunnel->stats.rx_bytes += length; |
| 256 | session->stats.rx_packets++; |
| 257 | session->stats.rx_bytes += length; |
| 258 | |
| 259 | if (L2TP_SKB_CB(skb)->has_seq) { |
| 260 | /* Bump our Nr */ |
| 261 | session->nr++; |
| 262 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 263 | "%s: updated nr to %hu\n", session->name, session->nr); |
| 264 | } |
| 265 | |
| 266 | /* call private receive handler */ |
| 267 | if (session->recv_skb != NULL) |
| 268 | (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); |
| 269 | else |
| 270 | kfree_skb(skb); |
| 271 | |
| 272 | if (session->deref) |
| 273 | (*session->deref)(session); |
| 274 | } |
| 275 | |
| 276 | /* Dequeue skbs from the session's reorder_q, subject to packet order. |
| 277 | * Skbs that have been in the queue for too long are simply discarded. |
| 278 | */ |
| 279 | static void l2tp_recv_dequeue(struct l2tp_session *session) |
| 280 | { |
| 281 | struct sk_buff *skb; |
| 282 | struct sk_buff *tmp; |
| 283 | |
| 284 | /* If the pkt at the head of the queue has the nr that we |
| 285 | * expect to send up next, dequeue it and any other |
| 286 | * in-sequence packets behind it. |
| 287 | */ |
| 288 | spin_lock_bh(&session->reorder_q.lock); |
| 289 | skb_queue_walk_safe(&session->reorder_q, skb, tmp) { |
| 290 | if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { |
| 291 | session->stats.rx_seq_discards++; |
| 292 | session->stats.rx_errors++; |
| 293 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 294 | "%s: oos pkt %hu len %d discarded (too old), " |
| 295 | "waiting for %hu, reorder_q_len=%d\n", |
| 296 | session->name, L2TP_SKB_CB(skb)->ns, |
| 297 | L2TP_SKB_CB(skb)->length, session->nr, |
| 298 | skb_queue_len(&session->reorder_q)); |
| 299 | __skb_unlink(skb, &session->reorder_q); |
| 300 | kfree_skb(skb); |
| 301 | if (session->deref) |
| 302 | (*session->deref)(session); |
| 303 | continue; |
| 304 | } |
| 305 | |
| 306 | if (L2TP_SKB_CB(skb)->has_seq) { |
| 307 | if (L2TP_SKB_CB(skb)->ns != session->nr) { |
| 308 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 309 | "%s: holding oos pkt %hu len %d, " |
| 310 | "waiting for %hu, reorder_q_len=%d\n", |
| 311 | session->name, L2TP_SKB_CB(skb)->ns, |
| 312 | L2TP_SKB_CB(skb)->length, session->nr, |
| 313 | skb_queue_len(&session->reorder_q)); |
| 314 | goto out; |
| 315 | } |
| 316 | } |
| 317 | __skb_unlink(skb, &session->reorder_q); |
| 318 | |
| 319 | /* Process the skb. We release the queue lock while we |
| 320 | * do so to let other contexts process the queue. |
| 321 | */ |
| 322 | spin_unlock_bh(&session->reorder_q.lock); |
| 323 | l2tp_recv_dequeue_skb(session, skb); |
| 324 | spin_lock_bh(&session->reorder_q.lock); |
| 325 | } |
| 326 | |
| 327 | out: |
| 328 | spin_unlock_bh(&session->reorder_q.lock); |
| 329 | } |
| 330 | |
| 331 | static inline int l2tp_verify_udp_checksum(struct sock *sk, |
| 332 | struct sk_buff *skb) |
| 333 | { |
| 334 | struct udphdr *uh = udp_hdr(skb); |
| 335 | u16 ulen = ntohs(uh->len); |
| 336 | struct inet_sock *inet; |
| 337 | __wsum psum; |
| 338 | |
| 339 | if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check) |
| 340 | return 0; |
| 341 | |
| 342 | inet = inet_sk(sk); |
| 343 | psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen, |
| 344 | IPPROTO_UDP, 0); |
| 345 | |
| 346 | if ((skb->ip_summed == CHECKSUM_COMPLETE) && |
| 347 | !csum_fold(csum_add(psum, skb->csum))) |
| 348 | return 0; |
| 349 | |
| 350 | skb->csum = psum; |
| 351 | |
| 352 | return __skb_checksum_complete(skb); |
| 353 | } |
| 354 | |
| 355 | /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame |
| 356 | * here. The skb is not on a list when we get here. |
| 357 | * Returns 0 if the packet was a data packet and was successfully passed on. |
| 358 | * Returns 1 if the packet was not a good data packet and could not be |
| 359 | * forwarded. All such packets are passed up to userspace to deal with. |
| 360 | */ |
| 361 | int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, |
| 362 | int (*payload_hook)(struct sk_buff *skb)) |
| 363 | { |
| 364 | struct l2tp_session *session = NULL; |
| 365 | unsigned char *ptr, *optr; |
| 366 | u16 hdrflags; |
| 367 | u32 tunnel_id, session_id; |
| 368 | int length; |
| 369 | int offset; |
| 370 | u16 version; |
| 371 | u16 ns, nr; |
| 372 | |
| 373 | if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) |
| 374 | goto discard_bad_csum; |
| 375 | |
| 376 | /* UDP always verifies the packet length. */ |
| 377 | __skb_pull(skb, sizeof(struct udphdr)); |
| 378 | |
| 379 | /* Short packet? */ |
| 380 | if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { |
| 381 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| 382 | "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); |
| 383 | goto error; |
| 384 | } |
| 385 | |
| 386 | /* Point to L2TP header */ |
| 387 | optr = ptr = skb->data; |
| 388 | |
| 389 | /* Trace packet contents, if enabled */ |
| 390 | if (tunnel->debug & L2TP_MSG_DATA) { |
| 391 | length = min(32u, skb->len); |
| 392 | if (!pskb_may_pull(skb, length)) |
| 393 | goto error; |
| 394 | |
| 395 | printk(KERN_DEBUG "%s: recv: ", tunnel->name); |
| 396 | |
| 397 | offset = 0; |
| 398 | do { |
| 399 | printk(" %02X", ptr[offset]); |
| 400 | } while (++offset < length); |
| 401 | |
| 402 | printk("\n"); |
| 403 | } |
| 404 | |
| 405 | /* Get L2TP header flags */ |
| 406 | hdrflags = ntohs(*(__be16 *)ptr); |
| 407 | |
| 408 | /* Check protocol version */ |
| 409 | version = hdrflags & L2TP_HDR_VER_MASK; |
| 410 | if (version != tunnel->version) { |
| 411 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| 412 | "%s: recv protocol version mismatch: got %d expected %d\n", |
| 413 | tunnel->name, version, tunnel->version); |
| 414 | goto error; |
| 415 | } |
| 416 | |
| 417 | /* Get length of L2TP packet */ |
| 418 | length = skb->len; |
| 419 | |
| 420 | /* If type is control packet, it is handled by userspace. */ |
| 421 | if (hdrflags & L2TP_HDRFLAG_T) { |
| 422 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| 423 | "%s: recv control packet, len=%d\n", tunnel->name, length); |
| 424 | goto error; |
| 425 | } |
| 426 | |
| 427 | /* Skip flags */ |
| 428 | ptr += 2; |
| 429 | |
| 430 | /* If length is present, skip it */ |
| 431 | if (hdrflags & L2TP_HDRFLAG_L) |
| 432 | ptr += 2; |
| 433 | |
| 434 | /* Extract tunnel and session ID */ |
| 435 | tunnel_id = ntohs(*(__be16 *) ptr); |
| 436 | ptr += 2; |
| 437 | session_id = ntohs(*(__be16 *) ptr); |
| 438 | ptr += 2; |
| 439 | |
| 440 | /* Find the session context */ |
| 441 | session = l2tp_session_find(tunnel, session_id); |
| 442 | if (!session) { |
| 443 | /* Not found? Pass to userspace to deal with */ |
| 444 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| 445 | "%s: no session found (%hu/%hu). Passing up.\n", |
| 446 | tunnel->name, tunnel_id, session_id); |
| 447 | goto error; |
| 448 | } |
| 449 | |
| 450 | /* The ref count is increased since we now hold a pointer to |
| 451 | * the session. Take care to decrement the refcnt when exiting |
| 452 | * this function from now on... |
| 453 | */ |
| 454 | l2tp_session_inc_refcount(session); |
| 455 | if (session->ref) |
| 456 | (*session->ref)(session); |
| 457 | |
| 458 | /* Handle the optional sequence numbers. Sequence numbers are |
| 459 | * in different places for L2TPv2 and L2TPv3. |
| 460 | * |
| 461 | * If we are the LAC, enable/disable sequence numbers under |
| 462 | * the control of the LNS. If no sequence numbers present but |
| 463 | * we were expecting them, discard frame. |
| 464 | */ |
| 465 | ns = nr = 0; |
| 466 | L2TP_SKB_CB(skb)->has_seq = 0; |
| 467 | if (hdrflags & L2TP_HDRFLAG_S) { |
| 468 | ns = (u16) ntohs(*(__be16 *) ptr); |
| 469 | ptr += 2; |
| 470 | nr = ntohs(*(__be16 *) ptr); |
| 471 | ptr += 2; |
| 472 | |
| 473 | /* Store L2TP info in the skb */ |
| 474 | L2TP_SKB_CB(skb)->ns = ns; |
| 475 | L2TP_SKB_CB(skb)->has_seq = 1; |
| 476 | |
| 477 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 478 | "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n", |
| 479 | session->name, ns, nr, session->nr); |
| 480 | } |
| 481 | |
| 482 | if (L2TP_SKB_CB(skb)->has_seq) { |
| 483 | /* Received a packet with sequence numbers. If we're the LNS, |
| 484 | * check if we sre sending sequence numbers and if not, |
| 485 | * configure it so. |
| 486 | */ |
| 487 | if ((!session->lns_mode) && (!session->send_seq)) { |
| 488 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, |
| 489 | "%s: requested to enable seq numbers by LNS\n", |
| 490 | session->name); |
| 491 | session->send_seq = -1; |
| 492 | } |
| 493 | } else { |
| 494 | /* No sequence numbers. |
| 495 | * If user has configured mandatory sequence numbers, discard. |
| 496 | */ |
| 497 | if (session->recv_seq) { |
| 498 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, |
| 499 | "%s: recv data has no seq numbers when required. " |
| 500 | "Discarding\n", session->name); |
| 501 | session->stats.rx_seq_discards++; |
| 502 | goto discard; |
| 503 | } |
| 504 | |
| 505 | /* If we're the LAC and we're sending sequence numbers, the |
| 506 | * LNS has requested that we no longer send sequence numbers. |
| 507 | * If we're the LNS and we're sending sequence numbers, the |
| 508 | * LAC is broken. Discard the frame. |
| 509 | */ |
| 510 | if ((!session->lns_mode) && (session->send_seq)) { |
| 511 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, |
| 512 | "%s: requested to disable seq numbers by LNS\n", |
| 513 | session->name); |
| 514 | session->send_seq = 0; |
| 515 | } else if (session->send_seq) { |
| 516 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, |
| 517 | "%s: recv data has no seq numbers when required. " |
| 518 | "Discarding\n", session->name); |
| 519 | session->stats.rx_seq_discards++; |
| 520 | goto discard; |
| 521 | } |
| 522 | } |
| 523 | |
| 524 | /* If offset bit set, skip it. */ |
| 525 | if (hdrflags & L2TP_HDRFLAG_O) { |
| 526 | offset = ntohs(*(__be16 *)ptr); |
| 527 | ptr += 2 + offset; |
| 528 | } |
| 529 | |
| 530 | offset = ptr - optr; |
| 531 | if (!pskb_may_pull(skb, offset)) |
| 532 | goto discard; |
| 533 | |
| 534 | __skb_pull(skb, offset); |
| 535 | |
| 536 | /* If caller wants to process the payload before we queue the |
| 537 | * packet, do so now. |
| 538 | */ |
| 539 | if (payload_hook) |
| 540 | if ((*payload_hook)(skb)) |
| 541 | goto discard; |
| 542 | |
| 543 | /* Prepare skb for adding to the session's reorder_q. Hold |
| 544 | * packets for max reorder_timeout or 1 second if not |
| 545 | * reordering. |
| 546 | */ |
| 547 | L2TP_SKB_CB(skb)->length = length; |
| 548 | L2TP_SKB_CB(skb)->expires = jiffies + |
| 549 | (session->reorder_timeout ? session->reorder_timeout : HZ); |
| 550 | |
| 551 | /* Add packet to the session's receive queue. Reordering is done here, if |
| 552 | * enabled. Saved L2TP protocol info is stored in skb->sb[]. |
| 553 | */ |
| 554 | if (L2TP_SKB_CB(skb)->has_seq) { |
| 555 | if (session->reorder_timeout != 0) { |
| 556 | /* Packet reordering enabled. Add skb to session's |
| 557 | * reorder queue, in order of ns. |
| 558 | */ |
| 559 | l2tp_recv_queue_skb(session, skb); |
| 560 | } else { |
| 561 | /* Packet reordering disabled. Discard out-of-sequence |
| 562 | * packets |
| 563 | */ |
| 564 | if (L2TP_SKB_CB(skb)->ns != session->nr) { |
| 565 | session->stats.rx_seq_discards++; |
| 566 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 567 | "%s: oos pkt %hu len %d discarded, " |
| 568 | "waiting for %hu, reorder_q_len=%d\n", |
| 569 | session->name, L2TP_SKB_CB(skb)->ns, |
| 570 | L2TP_SKB_CB(skb)->length, session->nr, |
| 571 | skb_queue_len(&session->reorder_q)); |
| 572 | goto discard; |
| 573 | } |
| 574 | skb_queue_tail(&session->reorder_q, skb); |
| 575 | } |
| 576 | } else { |
| 577 | /* No sequence numbers. Add the skb to the tail of the |
| 578 | * reorder queue. This ensures that it will be |
| 579 | * delivered after all previous sequenced skbs. |
| 580 | */ |
| 581 | skb_queue_tail(&session->reorder_q, skb); |
| 582 | } |
| 583 | |
| 584 | /* Try to dequeue as many skbs from reorder_q as we can. */ |
| 585 | l2tp_recv_dequeue(session); |
| 586 | |
| 587 | l2tp_session_dec_refcount(session); |
| 588 | |
| 589 | return 0; |
| 590 | |
| 591 | discard: |
| 592 | session->stats.rx_errors++; |
| 593 | kfree_skb(skb); |
| 594 | |
| 595 | if (session->deref) |
| 596 | (*session->deref)(session); |
| 597 | |
| 598 | l2tp_session_dec_refcount(session); |
| 599 | |
| 600 | return 0; |
| 601 | |
| 602 | discard_bad_csum: |
| 603 | LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); |
| 604 | UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); |
| 605 | tunnel->stats.rx_errors++; |
| 606 | kfree_skb(skb); |
| 607 | |
| 608 | return 0; |
| 609 | |
| 610 | error: |
| 611 | /* Put UDP header back */ |
| 612 | __skb_push(skb, sizeof(struct udphdr)); |
| 613 | |
| 614 | return 1; |
| 615 | } |
| 616 | EXPORT_SYMBOL_GPL(l2tp_udp_recv_core); |
| 617 | |
| 618 | /* UDP encapsulation receive handler. See net/ipv4/udp.c. |
| 619 | * Return codes: |
| 620 | * 0 : success. |
| 621 | * <0: error |
| 622 | * >0: skb should be passed up to userspace as UDP. |
| 623 | */ |
| 624 | int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) |
| 625 | { |
| 626 | struct l2tp_tunnel *tunnel; |
| 627 | |
| 628 | tunnel = l2tp_sock_to_tunnel(sk); |
| 629 | if (tunnel == NULL) |
| 630 | goto pass_up; |
| 631 | |
| 632 | PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| 633 | "%s: received %d bytes\n", tunnel->name, skb->len); |
| 634 | |
| 635 | if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) |
| 636 | goto pass_up_put; |
| 637 | |
| 638 | sock_put(sk); |
| 639 | return 0; |
| 640 | |
| 641 | pass_up_put: |
| 642 | sock_put(sk); |
| 643 | pass_up: |
| 644 | return 1; |
| 645 | } |
| 646 | EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); |
| 647 | |
| 648 | /************************************************************************ |
| 649 | * Transmit handling |
| 650 | ***********************************************************************/ |
| 651 | |
| 652 | /* Build an L2TP header for the session into the buffer provided. |
| 653 | */ |
| 654 | static void l2tp_build_l2tpv2_header(struct l2tp_tunnel *tunnel, |
| 655 | struct l2tp_session *session, |
| 656 | void *buf) |
| 657 | { |
| 658 | __be16 *bufp = buf; |
| 659 | u16 flags = L2TP_HDR_VER_2; |
| 660 | u32 tunnel_id = tunnel->peer_tunnel_id; |
| 661 | u32 session_id = session->peer_session_id; |
| 662 | |
| 663 | if (session->send_seq) |
| 664 | flags |= L2TP_HDRFLAG_S; |
| 665 | |
| 666 | /* Setup L2TP header. */ |
| 667 | *bufp++ = htons(flags); |
| 668 | *bufp++ = htons(tunnel_id); |
| 669 | *bufp++ = htons(session_id); |
| 670 | if (session->send_seq) { |
| 671 | *bufp++ = htons(session->ns); |
| 672 | *bufp++ = 0; |
| 673 | session->ns++; |
| 674 | PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| 675 | "%s: updated ns to %hu\n", session->name, session->ns); |
| 676 | } |
| 677 | } |
| 678 | |
| 679 | void l2tp_build_l2tp_header(struct l2tp_session *session, void *buf) |
| 680 | { |
| 681 | struct l2tp_tunnel *tunnel = session->tunnel; |
| 682 | |
| 683 | BUG_ON(tunnel->version != L2TP_HDR_VER_2); |
| 684 | l2tp_build_l2tpv2_header(tunnel, session, buf); |
| 685 | } |
| 686 | EXPORT_SYMBOL_GPL(l2tp_build_l2tp_header); |
| 687 | |
| 688 | int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len) |
| 689 | { |
| 690 | struct l2tp_tunnel *tunnel = session->tunnel; |
| 691 | unsigned int len = skb->len; |
| 692 | int error; |
| 693 | |
| 694 | /* Debug */ |
| 695 | if (session->send_seq) |
| 696 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| 697 | "%s: send %Zd bytes, ns=%hu\n", session->name, |
| 698 | data_len, session->ns - 1); |
| 699 | else |
| 700 | PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| 701 | "%s: send %Zd bytes\n", session->name, data_len); |
| 702 | |
| 703 | if (session->debug & L2TP_MSG_DATA) { |
| 704 | int i; |
| 705 | unsigned char *datap = skb->data + sizeof(struct udphdr); |
| 706 | |
| 707 | printk(KERN_DEBUG "%s: xmit:", session->name); |
| 708 | for (i = 0; i < (len - sizeof(struct udphdr)); i++) { |
| 709 | printk(" %02X", *datap++); |
| 710 | if (i == 31) { |
| 711 | printk(" ..."); |
| 712 | break; |
| 713 | } |
| 714 | } |
| 715 | printk("\n"); |
| 716 | } |
| 717 | |
| 718 | /* Queue the packet to IP for output */ |
| 719 | error = ip_queue_xmit(skb, 1); |
| 720 | |
| 721 | /* Update stats */ |
| 722 | if (error >= 0) { |
| 723 | tunnel->stats.tx_packets++; |
| 724 | tunnel->stats.tx_bytes += len; |
| 725 | session->stats.tx_packets++; |
| 726 | session->stats.tx_bytes += len; |
| 727 | } else { |
| 728 | tunnel->stats.tx_errors++; |
| 729 | session->stats.tx_errors++; |
| 730 | } |
| 731 | |
| 732 | return 0; |
| 733 | } |
| 734 | EXPORT_SYMBOL_GPL(l2tp_xmit_core); |
| 735 | |
| 736 | /* Automatically called when the skb is freed. |
| 737 | */ |
| 738 | static void l2tp_sock_wfree(struct sk_buff *skb) |
| 739 | { |
| 740 | sock_put(skb->sk); |
| 741 | } |
| 742 | |
| 743 | /* For data skbs that we transmit, we associate with the tunnel socket |
| 744 | * but don't do accounting. |
| 745 | */ |
| 746 | static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) |
| 747 | { |
| 748 | sock_hold(sk); |
| 749 | skb->sk = sk; |
| 750 | skb->destructor = l2tp_sock_wfree; |
| 751 | } |
| 752 | |
| 753 | /* If caller requires the skb to have a ppp header, the header must be |
| 754 | * inserted in the skb data before calling this function. |
| 755 | */ |
| 756 | int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) |
| 757 | { |
| 758 | int data_len = skb->len; |
| 759 | struct sock *sk = session->tunnel->sock; |
| 760 | struct udphdr *uh; |
| 761 | unsigned int udp_len; |
| 762 | struct inet_sock *inet; |
| 763 | __wsum csum; |
| 764 | int old_headroom; |
| 765 | int new_headroom; |
| 766 | int headroom; |
| 767 | |
| 768 | /* Check that there's enough headroom in the skb to insert IP, |
| 769 | * UDP and L2TP headers. If not enough, expand it to |
| 770 | * make room. Adjust truesize. |
| 771 | */ |
| 772 | headroom = NET_SKB_PAD + sizeof(struct iphdr) + |
| 773 | sizeof(struct udphdr) + hdr_len; |
| 774 | old_headroom = skb_headroom(skb); |
| 775 | if (skb_cow_head(skb, headroom)) |
| 776 | goto abort; |
| 777 | |
| 778 | new_headroom = skb_headroom(skb); |
| 779 | skb_orphan(skb); |
| 780 | skb->truesize += new_headroom - old_headroom; |
| 781 | |
| 782 | /* Setup L2TP header */ |
| 783 | l2tp_build_l2tp_header(session, __skb_push(skb, hdr_len)); |
| 784 | udp_len = sizeof(struct udphdr) + hdr_len + data_len; |
| 785 | |
| 786 | /* Setup UDP header */ |
| 787 | inet = inet_sk(sk); |
| 788 | __skb_push(skb, sizeof(*uh)); |
| 789 | skb_reset_transport_header(skb); |
| 790 | uh = udp_hdr(skb); |
| 791 | uh->source = inet->inet_sport; |
| 792 | uh->dest = inet->inet_dport; |
| 793 | uh->len = htons(udp_len); |
| 794 | |
| 795 | uh->check = 0; |
| 796 | |
| 797 | memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); |
| 798 | IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | |
| 799 | IPSKB_REROUTED); |
| 800 | nf_reset(skb); |
| 801 | |
| 802 | /* Get routing info from the tunnel socket */ |
| 803 | skb_dst_drop(skb); |
| 804 | skb_dst_set(skb, dst_clone(__sk_dst_get(sk))); |
| 805 | l2tp_skb_set_owner_w(skb, sk); |
| 806 | |
| 807 | /* Calculate UDP checksum if configured to do so */ |
| 808 | if (sk->sk_no_check == UDP_CSUM_NOXMIT) |
| 809 | skb->ip_summed = CHECKSUM_NONE; |
| 810 | else if ((skb_dst(skb) && skb_dst(skb)->dev) && |
| 811 | (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { |
| 812 | skb->ip_summed = CHECKSUM_COMPLETE; |
| 813 | csum = skb_checksum(skb, 0, udp_len, 0); |
| 814 | uh->check = csum_tcpudp_magic(inet->inet_saddr, |
| 815 | inet->inet_daddr, |
| 816 | udp_len, IPPROTO_UDP, csum); |
| 817 | if (uh->check == 0) |
| 818 | uh->check = CSUM_MANGLED_0; |
| 819 | } else { |
| 820 | skb->ip_summed = CHECKSUM_PARTIAL; |
| 821 | skb->csum_start = skb_transport_header(skb) - skb->head; |
| 822 | skb->csum_offset = offsetof(struct udphdr, check); |
| 823 | uh->check = ~csum_tcpudp_magic(inet->inet_saddr, |
| 824 | inet->inet_daddr, |
| 825 | udp_len, IPPROTO_UDP, 0); |
| 826 | } |
| 827 | |
| 828 | l2tp_xmit_core(session, skb, data_len); |
| 829 | |
| 830 | abort: |
| 831 | return 0; |
| 832 | } |
| 833 | EXPORT_SYMBOL_GPL(l2tp_xmit_skb); |
| 834 | |
| 835 | /***************************************************************************** |
| 836 | * Tinnel and session create/destroy. |
| 837 | *****************************************************************************/ |
| 838 | |
| 839 | /* Tunnel socket destruct hook. |
| 840 | * The tunnel context is deleted only when all session sockets have been |
| 841 | * closed. |
| 842 | */ |
| 843 | void l2tp_tunnel_destruct(struct sock *sk) |
| 844 | { |
| 845 | struct l2tp_tunnel *tunnel; |
| 846 | |
| 847 | tunnel = sk->sk_user_data; |
| 848 | if (tunnel == NULL) |
| 849 | goto end; |
| 850 | |
| 851 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| 852 | "%s: closing...\n", tunnel->name); |
| 853 | |
| 854 | /* Close all sessions */ |
| 855 | l2tp_tunnel_closeall(tunnel); |
| 856 | |
| 857 | /* No longer an encapsulation socket. See net/ipv4/udp.c */ |
| 858 | (udp_sk(sk))->encap_type = 0; |
| 859 | (udp_sk(sk))->encap_rcv = NULL; |
| 860 | |
| 861 | /* Remove hooks into tunnel socket */ |
| 862 | tunnel->sock = NULL; |
| 863 | sk->sk_destruct = tunnel->old_sk_destruct; |
| 864 | sk->sk_user_data = NULL; |
| 865 | |
| 866 | /* Call the original destructor */ |
| 867 | if (sk->sk_destruct) |
| 868 | (*sk->sk_destruct)(sk); |
| 869 | |
| 870 | /* We're finished with the socket */ |
| 871 | l2tp_tunnel_dec_refcount(tunnel); |
| 872 | |
| 873 | end: |
| 874 | return; |
| 875 | } |
| 876 | EXPORT_SYMBOL(l2tp_tunnel_destruct); |
| 877 | |
| 878 | /* When the tunnel is closed, all the attached sessions need to go too. |
| 879 | */ |
| 880 | void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) |
| 881 | { |
| 882 | int hash; |
| 883 | struct hlist_node *walk; |
| 884 | struct hlist_node *tmp; |
| 885 | struct l2tp_session *session; |
| 886 | |
| 887 | BUG_ON(tunnel == NULL); |
| 888 | |
| 889 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| 890 | "%s: closing all sessions...\n", tunnel->name); |
| 891 | |
| 892 | write_lock_bh(&tunnel->hlist_lock); |
| 893 | for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { |
| 894 | again: |
| 895 | hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { |
| 896 | session = hlist_entry(walk, struct l2tp_session, hlist); |
| 897 | |
| 898 | PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| 899 | "%s: closing session\n", session->name); |
| 900 | |
| 901 | hlist_del_init(&session->hlist); |
| 902 | |
| 903 | /* Since we should hold the sock lock while |
| 904 | * doing any unbinding, we need to release the |
| 905 | * lock we're holding before taking that lock. |
| 906 | * Hold a reference to the sock so it doesn't |
| 907 | * disappear as we're jumping between locks. |
| 908 | */ |
| 909 | if (session->ref != NULL) |
| 910 | (*session->ref)(session); |
| 911 | |
| 912 | write_unlock_bh(&tunnel->hlist_lock); |
| 913 | |
| 914 | if (session->session_close != NULL) |
| 915 | (*session->session_close)(session); |
| 916 | |
| 917 | if (session->deref != NULL) |
| 918 | (*session->deref)(session); |
| 919 | |
| 920 | write_lock_bh(&tunnel->hlist_lock); |
| 921 | |
| 922 | /* Now restart from the beginning of this hash |
| 923 | * chain. We always remove a session from the |
| 924 | * list so we are guaranteed to make forward |
| 925 | * progress. |
| 926 | */ |
| 927 | goto again; |
| 928 | } |
| 929 | } |
| 930 | write_unlock_bh(&tunnel->hlist_lock); |
| 931 | } |
| 932 | EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall); |
| 933 | |
| 934 | /* Really kill the tunnel. |
| 935 | * Come here only when all sessions have been cleared from the tunnel. |
| 936 | */ |
| 937 | void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) |
| 938 | { |
| 939 | struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); |
| 940 | |
| 941 | BUG_ON(atomic_read(&tunnel->ref_count) != 0); |
| 942 | BUG_ON(tunnel->sock != NULL); |
| 943 | |
| 944 | PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| 945 | "%s: free...\n", tunnel->name); |
| 946 | |
| 947 | /* Remove from tunnel list */ |
| 948 | write_lock_bh(&pn->l2tp_tunnel_list_lock); |
| 949 | list_del_init(&tunnel->list); |
| 950 | write_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 951 | |
| 952 | atomic_dec(&l2tp_tunnel_count); |
| 953 | kfree(tunnel); |
| 954 | } |
| 955 | EXPORT_SYMBOL_GPL(l2tp_tunnel_free); |
| 956 | |
| 957 | int 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) |
| 958 | { |
| 959 | struct l2tp_tunnel *tunnel = NULL; |
| 960 | int err; |
| 961 | struct socket *sock = NULL; |
| 962 | struct sock *sk = NULL; |
| 963 | struct l2tp_net *pn; |
| 964 | |
| 965 | /* Get the tunnel socket from the fd, which was opened by |
| 966 | * the userspace L2TP daemon. |
| 967 | */ |
| 968 | err = -EBADF; |
| 969 | sock = sockfd_lookup(fd, &err); |
| 970 | if (!sock) { |
| 971 | printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", |
| 972 | tunnel_id, fd, err); |
| 973 | goto err; |
| 974 | } |
| 975 | |
| 976 | sk = sock->sk; |
| 977 | |
| 978 | /* Quick sanity checks */ |
| 979 | err = -EPROTONOSUPPORT; |
| 980 | if (sk->sk_protocol != IPPROTO_UDP) { |
| 981 | printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", |
| 982 | tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); |
| 983 | goto err; |
| 984 | } |
| 985 | err = -EAFNOSUPPORT; |
| 986 | if (sock->ops->family != AF_INET) { |
| 987 | printk(KERN_ERR "tunl %hu: fd %d wrong family, got %d, expected %d\n", |
| 988 | tunnel_id, fd, sock->ops->family, AF_INET); |
| 989 | goto err; |
| 990 | } |
| 991 | |
| 992 | /* Check if this socket has already been prepped */ |
| 993 | tunnel = (struct l2tp_tunnel *)sk->sk_user_data; |
| 994 | if (tunnel != NULL) { |
| 995 | /* This socket has already been prepped */ |
| 996 | err = -EBUSY; |
| 997 | goto err; |
| 998 | } |
| 999 | |
| 1000 | if (version != L2TP_HDR_VER_2) |
| 1001 | goto err; |
| 1002 | |
| 1003 | tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); |
| 1004 | if (tunnel == NULL) { |
| 1005 | err = -ENOMEM; |
| 1006 | goto err; |
| 1007 | } |
| 1008 | |
| 1009 | tunnel->version = version; |
| 1010 | tunnel->tunnel_id = tunnel_id; |
| 1011 | tunnel->peer_tunnel_id = peer_tunnel_id; |
| 1012 | tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; |
| 1013 | |
| 1014 | tunnel->magic = L2TP_TUNNEL_MAGIC; |
| 1015 | sprintf(&tunnel->name[0], "tunl %u", tunnel_id); |
| 1016 | rwlock_init(&tunnel->hlist_lock); |
| 1017 | |
| 1018 | /* The net we belong to */ |
| 1019 | tunnel->l2tp_net = net; |
| 1020 | pn = l2tp_pernet(net); |
| 1021 | |
| 1022 | if (cfg) |
| 1023 | tunnel->debug = cfg->debug; |
| 1024 | |
| 1025 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ |
| 1026 | udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; |
| 1027 | udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; |
| 1028 | |
| 1029 | sk->sk_user_data = tunnel; |
| 1030 | |
| 1031 | /* Hook on the tunnel socket destructor so that we can cleanup |
| 1032 | * if the tunnel socket goes away. |
| 1033 | */ |
| 1034 | tunnel->old_sk_destruct = sk->sk_destruct; |
| 1035 | sk->sk_destruct = &l2tp_tunnel_destruct; |
| 1036 | tunnel->sock = sk; |
| 1037 | sk->sk_allocation = GFP_ATOMIC; |
| 1038 | |
| 1039 | /* Add tunnel to our list */ |
| 1040 | INIT_LIST_HEAD(&tunnel->list); |
| 1041 | write_lock_bh(&pn->l2tp_tunnel_list_lock); |
| 1042 | list_add(&tunnel->list, &pn->l2tp_tunnel_list); |
| 1043 | write_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| 1044 | atomic_inc(&l2tp_tunnel_count); |
| 1045 | |
| 1046 | /* Bump the reference count. The tunnel context is deleted |
| 1047 | * only when this drops to zero. |
| 1048 | */ |
| 1049 | l2tp_tunnel_inc_refcount(tunnel); |
| 1050 | |
| 1051 | err = 0; |
| 1052 | err: |
| 1053 | if (tunnelp) |
| 1054 | *tunnelp = tunnel; |
| 1055 | |
| 1056 | if (sock) |
| 1057 | sockfd_put(sock); |
| 1058 | |
| 1059 | return err; |
| 1060 | } |
| 1061 | EXPORT_SYMBOL_GPL(l2tp_tunnel_create); |
| 1062 | |
| 1063 | /* Really kill the session. |
| 1064 | */ |
| 1065 | void l2tp_session_free(struct l2tp_session *session) |
| 1066 | { |
| 1067 | struct l2tp_tunnel *tunnel; |
| 1068 | |
| 1069 | BUG_ON(atomic_read(&session->ref_count) != 0); |
| 1070 | |
| 1071 | tunnel = session->tunnel; |
| 1072 | if (tunnel != NULL) { |
| 1073 | BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); |
| 1074 | |
| 1075 | /* Delete the session from the hash */ |
| 1076 | write_lock_bh(&tunnel->hlist_lock); |
| 1077 | hlist_del_init(&session->hlist); |
| 1078 | write_unlock_bh(&tunnel->hlist_lock); |
| 1079 | |
| 1080 | if (session->session_id != 0) |
| 1081 | atomic_dec(&l2tp_session_count); |
| 1082 | |
| 1083 | sock_put(tunnel->sock); |
| 1084 | |
| 1085 | /* This will delete the tunnel context if this |
| 1086 | * is the last session on the tunnel. |
| 1087 | */ |
| 1088 | session->tunnel = NULL; |
| 1089 | l2tp_tunnel_dec_refcount(tunnel); |
| 1090 | } |
| 1091 | |
| 1092 | kfree(session); |
| 1093 | |
| 1094 | return; |
| 1095 | } |
| 1096 | EXPORT_SYMBOL_GPL(l2tp_session_free); |
| 1097 | |
| 1098 | struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) |
| 1099 | { |
| 1100 | struct l2tp_session *session; |
| 1101 | |
| 1102 | session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); |
| 1103 | if (session != NULL) { |
| 1104 | session->magic = L2TP_SESSION_MAGIC; |
| 1105 | session->tunnel = tunnel; |
| 1106 | |
| 1107 | session->session_id = session_id; |
| 1108 | session->peer_session_id = peer_session_id; |
| 1109 | |
| 1110 | sprintf(&session->name[0], "sess %u/%u", |
| 1111 | tunnel->tunnel_id, session->session_id); |
| 1112 | |
| 1113 | skb_queue_head_init(&session->reorder_q); |
| 1114 | |
| 1115 | INIT_HLIST_NODE(&session->hlist); |
| 1116 | |
| 1117 | /* Inherit debug options from tunnel */ |
| 1118 | session->debug = tunnel->debug; |
| 1119 | |
| 1120 | if (cfg) { |
| 1121 | session->debug = cfg->debug; |
| 1122 | session->hdr_len = cfg->hdr_len; |
| 1123 | session->mtu = cfg->mtu; |
| 1124 | session->mru = cfg->mru; |
| 1125 | session->send_seq = cfg->send_seq; |
| 1126 | session->recv_seq = cfg->recv_seq; |
| 1127 | session->lns_mode = cfg->lns_mode; |
| 1128 | } |
| 1129 | |
| 1130 | /* Bump the reference count. The session context is deleted |
| 1131 | * only when this drops to zero. |
| 1132 | */ |
| 1133 | l2tp_session_inc_refcount(session); |
| 1134 | l2tp_tunnel_inc_refcount(tunnel); |
| 1135 | |
| 1136 | /* Ensure tunnel socket isn't deleted */ |
| 1137 | sock_hold(tunnel->sock); |
| 1138 | |
| 1139 | /* Add session to the tunnel's hash list */ |
| 1140 | write_lock_bh(&tunnel->hlist_lock); |
| 1141 | hlist_add_head(&session->hlist, |
| 1142 | l2tp_session_id_hash(tunnel, session_id)); |
| 1143 | write_unlock_bh(&tunnel->hlist_lock); |
| 1144 | |
| 1145 | /* Ignore management session in session count value */ |
| 1146 | if (session->session_id != 0) |
| 1147 | atomic_inc(&l2tp_session_count); |
| 1148 | } |
| 1149 | |
| 1150 | return session; |
| 1151 | } |
| 1152 | EXPORT_SYMBOL_GPL(l2tp_session_create); |
| 1153 | |
| 1154 | /***************************************************************************** |
| 1155 | * Init and cleanup |
| 1156 | *****************************************************************************/ |
| 1157 | |
| 1158 | static __net_init int l2tp_init_net(struct net *net) |
| 1159 | { |
| 1160 | struct l2tp_net *pn; |
| 1161 | int err; |
| 1162 | |
| 1163 | pn = kzalloc(sizeof(*pn), GFP_KERNEL); |
| 1164 | if (!pn) |
| 1165 | return -ENOMEM; |
| 1166 | |
| 1167 | INIT_LIST_HEAD(&pn->l2tp_tunnel_list); |
| 1168 | rwlock_init(&pn->l2tp_tunnel_list_lock); |
| 1169 | |
| 1170 | err = net_assign_generic(net, l2tp_net_id, pn); |
| 1171 | if (err) |
| 1172 | goto out; |
| 1173 | |
| 1174 | return 0; |
| 1175 | |
| 1176 | out: |
| 1177 | kfree(pn); |
| 1178 | return err; |
| 1179 | } |
| 1180 | |
| 1181 | static __net_exit void l2tp_exit_net(struct net *net) |
| 1182 | { |
| 1183 | struct l2tp_net *pn; |
| 1184 | |
| 1185 | pn = net_generic(net, l2tp_net_id); |
| 1186 | /* |
| 1187 | * if someone has cached our net then |
| 1188 | * further net_generic call will return NULL |
| 1189 | */ |
| 1190 | net_assign_generic(net, l2tp_net_id, NULL); |
| 1191 | kfree(pn); |
| 1192 | } |
| 1193 | |
| 1194 | static struct pernet_operations l2tp_net_ops = { |
| 1195 | .init = l2tp_init_net, |
| 1196 | .exit = l2tp_exit_net, |
| 1197 | .id = &l2tp_net_id, |
| 1198 | .size = sizeof(struct l2tp_net), |
| 1199 | }; |
| 1200 | |
| 1201 | static int __init l2tp_init(void) |
| 1202 | { |
| 1203 | int rc = 0; |
| 1204 | |
| 1205 | rc = register_pernet_device(&l2tp_net_ops); |
| 1206 | if (rc) |
| 1207 | goto out; |
| 1208 | |
| 1209 | printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); |
| 1210 | |
| 1211 | out: |
| 1212 | return rc; |
| 1213 | } |
| 1214 | |
| 1215 | static void __exit l2tp_exit(void) |
| 1216 | { |
| 1217 | unregister_pernet_device(&l2tp_net_ops); |
| 1218 | } |
| 1219 | |
| 1220 | module_init(l2tp_init); |
| 1221 | module_exit(l2tp_exit); |
| 1222 | |
| 1223 | MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); |
| 1224 | MODULE_DESCRIPTION("L2TP core"); |
| 1225 | MODULE_LICENSE("GPL"); |
| 1226 | MODULE_VERSION(L2TP_DRV_VERSION); |
| 1227 | |