1fd558d18SJames Chapman /* 2fd558d18SJames Chapman * L2TP core. 3fd558d18SJames Chapman * 4fd558d18SJames Chapman * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 5fd558d18SJames Chapman * 6fd558d18SJames Chapman * This file contains some code of the original L2TPv2 pppol2tp 7fd558d18SJames Chapman * driver, which has the following copyright: 8fd558d18SJames Chapman * 9fd558d18SJames Chapman * Authors: Martijn van Oosterhout <kleptog@svana.org> 10fd558d18SJames Chapman * James Chapman (jchapman@katalix.com) 11fd558d18SJames Chapman * Contributors: 12fd558d18SJames Chapman * Michal Ostrowski <mostrows@speakeasy.net> 13fd558d18SJames Chapman * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> 14fd558d18SJames Chapman * David S. Miller (davem@redhat.com) 15fd558d18SJames Chapman * 16fd558d18SJames Chapman * This program is free software; you can redistribute it and/or modify 17fd558d18SJames Chapman * it under the terms of the GNU General Public License version 2 as 18fd558d18SJames Chapman * published by the Free Software Foundation. 19fd558d18SJames Chapman */ 20fd558d18SJames Chapman 21fd558d18SJames Chapman #include <linux/module.h> 22fd558d18SJames Chapman #include <linux/string.h> 23fd558d18SJames Chapman #include <linux/list.h> 24e02d494dSJames Chapman #include <linux/rculist.h> 25fd558d18SJames Chapman #include <linux/uaccess.h> 26fd558d18SJames Chapman 27fd558d18SJames Chapman #include <linux/kernel.h> 28fd558d18SJames Chapman #include <linux/spinlock.h> 29fd558d18SJames Chapman #include <linux/kthread.h> 30fd558d18SJames Chapman #include <linux/sched.h> 31fd558d18SJames Chapman #include <linux/slab.h> 32fd558d18SJames Chapman #include <linux/errno.h> 33fd558d18SJames Chapman #include <linux/jiffies.h> 34fd558d18SJames Chapman 35fd558d18SJames Chapman #include <linux/netdevice.h> 36fd558d18SJames Chapman #include <linux/net.h> 37fd558d18SJames Chapman #include <linux/inetdevice.h> 38fd558d18SJames Chapman #include <linux/skbuff.h> 39fd558d18SJames Chapman #include <linux/init.h> 400d76751fSJames Chapman #include <linux/in.h> 41fd558d18SJames Chapman #include <linux/ip.h> 42fd558d18SJames Chapman #include <linux/udp.h> 430d76751fSJames Chapman #include <linux/l2tp.h> 44fd558d18SJames Chapman #include <linux/hash.h> 45fd558d18SJames Chapman #include <linux/sort.h> 46fd558d18SJames Chapman #include <linux/file.h> 47fd558d18SJames Chapman #include <linux/nsproxy.h> 48fd558d18SJames Chapman #include <net/net_namespace.h> 49fd558d18SJames Chapman #include <net/netns/generic.h> 50fd558d18SJames Chapman #include <net/dst.h> 51fd558d18SJames Chapman #include <net/ip.h> 52fd558d18SJames Chapman #include <net/udp.h> 53309795f4SJames Chapman #include <net/inet_common.h> 54fd558d18SJames Chapman #include <net/xfrm.h> 550d76751fSJames Chapman #include <net/protocol.h> 56d2cf3361SBenjamin LaHaise #include <net/inet6_connection_sock.h> 57d2cf3361SBenjamin LaHaise #include <net/inet_ecn.h> 58d2cf3361SBenjamin LaHaise #include <net/ip6_route.h> 59fd558d18SJames Chapman 60fd558d18SJames Chapman #include <asm/byteorder.h> 6160063497SArun Sharma #include <linux/atomic.h> 62fd558d18SJames Chapman 63fd558d18SJames Chapman #include "l2tp_core.h" 64fd558d18SJames Chapman 65fd558d18SJames Chapman #define L2TP_DRV_VERSION "V2.0" 66fd558d18SJames Chapman 67fd558d18SJames Chapman /* L2TP header constants */ 68fd558d18SJames Chapman #define L2TP_HDRFLAG_T 0x8000 69fd558d18SJames Chapman #define L2TP_HDRFLAG_L 0x4000 70fd558d18SJames Chapman #define L2TP_HDRFLAG_S 0x0800 71fd558d18SJames Chapman #define L2TP_HDRFLAG_O 0x0200 72fd558d18SJames Chapman #define L2TP_HDRFLAG_P 0x0100 73fd558d18SJames Chapman 74fd558d18SJames Chapman #define L2TP_HDR_VER_MASK 0x000F 75fd558d18SJames Chapman #define L2TP_HDR_VER_2 0x0002 76f7faffa3SJames Chapman #define L2TP_HDR_VER_3 0x0003 77fd558d18SJames Chapman 78fd558d18SJames Chapman /* L2TPv3 default L2-specific sublayer */ 79fd558d18SJames Chapman #define L2TP_SLFLAG_S 0x40000000 80fd558d18SJames Chapman #define L2TP_SL_SEQ_MASK 0x00ffffff 81fd558d18SJames Chapman 82fd558d18SJames Chapman #define L2TP_HDR_SIZE_SEQ 10 83fd558d18SJames Chapman #define L2TP_HDR_SIZE_NOSEQ 6 84fd558d18SJames Chapman 85fd558d18SJames Chapman /* Default trace flags */ 86fd558d18SJames Chapman #define L2TP_DEFAULT_DEBUG_FLAGS 0 87fd558d18SJames Chapman 88fd558d18SJames Chapman #define PRINTK(_mask, _type, _lvl, _fmt, args...) \ 89fd558d18SJames Chapman do { \ 90fd558d18SJames Chapman if ((_mask) & (_type)) \ 91fd558d18SJames Chapman printk(_lvl "L2TP: " _fmt, ##args); \ 92fd558d18SJames Chapman } while (0) 93fd558d18SJames Chapman 94fd558d18SJames Chapman /* Private data stored for received packets in the skb. 95fd558d18SJames Chapman */ 96fd558d18SJames Chapman struct l2tp_skb_cb { 97f7faffa3SJames Chapman u32 ns; 98fd558d18SJames Chapman u16 has_seq; 99fd558d18SJames Chapman u16 length; 100fd558d18SJames Chapman unsigned long expires; 101fd558d18SJames Chapman }; 102fd558d18SJames Chapman 103fd558d18SJames Chapman #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) 104fd558d18SJames Chapman 105fd558d18SJames Chapman static atomic_t l2tp_tunnel_count; 106fd558d18SJames Chapman static atomic_t l2tp_session_count; 107fd558d18SJames Chapman 108fd558d18SJames Chapman /* per-net private data for this module */ 109fd558d18SJames Chapman static unsigned int l2tp_net_id; 110fd558d18SJames Chapman struct l2tp_net { 111fd558d18SJames Chapman struct list_head l2tp_tunnel_list; 112e02d494dSJames Chapman spinlock_t l2tp_tunnel_list_lock; 113f7faffa3SJames Chapman struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; 114e02d494dSJames Chapman spinlock_t l2tp_session_hlist_lock; 115fd558d18SJames Chapman }; 116fd558d18SJames Chapman 117fc130840Sstephen hemminger static void l2tp_session_set_header_len(struct l2tp_session *session, int version); 118fc130840Sstephen hemminger static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); 119fc130840Sstephen hemminger static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); 120fc130840Sstephen hemminger 121fd558d18SJames Chapman static inline struct l2tp_net *l2tp_pernet(struct net *net) 122fd558d18SJames Chapman { 123fd558d18SJames Chapman BUG_ON(!net); 124fd558d18SJames Chapman 125fd558d18SJames Chapman return net_generic(net, l2tp_net_id); 126fd558d18SJames Chapman } 127fd558d18SJames Chapman 128fc130840Sstephen hemminger 129fc130840Sstephen hemminger /* Tunnel reference counts. Incremented per session that is added to 130fc130840Sstephen hemminger * the tunnel. 131fc130840Sstephen hemminger */ 132fc130840Sstephen hemminger static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) 133fc130840Sstephen hemminger { 134fc130840Sstephen hemminger atomic_inc(&tunnel->ref_count); 135fc130840Sstephen hemminger } 136fc130840Sstephen hemminger 137fc130840Sstephen hemminger static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) 138fc130840Sstephen hemminger { 139fc130840Sstephen hemminger if (atomic_dec_and_test(&tunnel->ref_count)) 140fc130840Sstephen hemminger l2tp_tunnel_free(tunnel); 141fc130840Sstephen hemminger } 142fc130840Sstephen hemminger #ifdef L2TP_REFCNT_DEBUG 143fc130840Sstephen hemminger #define l2tp_tunnel_inc_refcount(_t) do { \ 144fc130840Sstephen hemminger printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ 145fc130840Sstephen hemminger l2tp_tunnel_inc_refcount_1(_t); \ 146fc130840Sstephen hemminger } while (0) 147fc130840Sstephen hemminger #define l2tp_tunnel_dec_refcount(_t) do { \ 148fc130840Sstephen hemminger printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ 149fc130840Sstephen hemminger l2tp_tunnel_dec_refcount_1(_t); \ 150fc130840Sstephen hemminger } while (0) 151fc130840Sstephen hemminger #else 152fc130840Sstephen hemminger #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) 153fc130840Sstephen hemminger #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) 154fc130840Sstephen hemminger #endif 155fc130840Sstephen hemminger 156f7faffa3SJames Chapman /* Session hash global list for L2TPv3. 157f7faffa3SJames Chapman * The session_id SHOULD be random according to RFC3931, but several 158f7faffa3SJames Chapman * L2TP implementations use incrementing session_ids. So we do a real 159f7faffa3SJames Chapman * hash on the session_id, rather than a simple bitmask. 160f7faffa3SJames Chapman */ 161f7faffa3SJames Chapman static inline struct hlist_head * 162f7faffa3SJames Chapman l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) 163f7faffa3SJames Chapman { 164f7faffa3SJames Chapman return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; 165f7faffa3SJames Chapman 166f7faffa3SJames Chapman } 167f7faffa3SJames Chapman 168f7faffa3SJames Chapman /* Lookup a session by id in the global session list 169f7faffa3SJames Chapman */ 170f7faffa3SJames Chapman static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) 171f7faffa3SJames Chapman { 172f7faffa3SJames Chapman struct l2tp_net *pn = l2tp_pernet(net); 173f7faffa3SJames Chapman struct hlist_head *session_list = 174f7faffa3SJames Chapman l2tp_session_id_hash_2(pn, session_id); 175f7faffa3SJames Chapman struct l2tp_session *session; 176f7faffa3SJames Chapman struct hlist_node *walk; 177f7faffa3SJames Chapman 178e02d494dSJames Chapman rcu_read_lock_bh(); 179e02d494dSJames Chapman hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) { 180f7faffa3SJames Chapman if (session->session_id == session_id) { 181e02d494dSJames Chapman rcu_read_unlock_bh(); 182f7faffa3SJames Chapman return session; 183f7faffa3SJames Chapman } 184f7faffa3SJames Chapman } 185e02d494dSJames Chapman rcu_read_unlock_bh(); 186f7faffa3SJames Chapman 187f7faffa3SJames Chapman return NULL; 188f7faffa3SJames Chapman } 189f7faffa3SJames Chapman 190fd558d18SJames Chapman /* Session hash list. 191fd558d18SJames Chapman * The session_id SHOULD be random according to RFC2661, but several 192fd558d18SJames Chapman * L2TP implementations (Cisco and Microsoft) use incrementing 193fd558d18SJames Chapman * session_ids. So we do a real hash on the session_id, rather than a 194fd558d18SJames Chapman * simple bitmask. 195fd558d18SJames Chapman */ 196fd558d18SJames Chapman static inline struct hlist_head * 197fd558d18SJames Chapman l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) 198fd558d18SJames Chapman { 199fd558d18SJames Chapman return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; 200fd558d18SJames Chapman } 201fd558d18SJames Chapman 202fd558d18SJames Chapman /* Lookup a session by id 203fd558d18SJames Chapman */ 204f7faffa3SJames Chapman struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) 205fd558d18SJames Chapman { 206f7faffa3SJames Chapman struct hlist_head *session_list; 207fd558d18SJames Chapman struct l2tp_session *session; 208fd558d18SJames Chapman struct hlist_node *walk; 209fd558d18SJames Chapman 210f7faffa3SJames Chapman /* In L2TPv3, session_ids are unique over all tunnels and we 211f7faffa3SJames Chapman * sometimes need to look them up before we know the 212f7faffa3SJames Chapman * tunnel. 213f7faffa3SJames Chapman */ 214f7faffa3SJames Chapman if (tunnel == NULL) 215f7faffa3SJames Chapman return l2tp_session_find_2(net, session_id); 216f7faffa3SJames Chapman 217f7faffa3SJames Chapman session_list = l2tp_session_id_hash(tunnel, session_id); 218fd558d18SJames Chapman read_lock_bh(&tunnel->hlist_lock); 219fd558d18SJames Chapman hlist_for_each_entry(session, walk, session_list, hlist) { 220fd558d18SJames Chapman if (session->session_id == session_id) { 221fd558d18SJames Chapman read_unlock_bh(&tunnel->hlist_lock); 222fd558d18SJames Chapman return session; 223fd558d18SJames Chapman } 224fd558d18SJames Chapman } 225fd558d18SJames Chapman read_unlock_bh(&tunnel->hlist_lock); 226fd558d18SJames Chapman 227fd558d18SJames Chapman return NULL; 228fd558d18SJames Chapman } 229fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_find); 230fd558d18SJames Chapman 231fd558d18SJames Chapman struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) 232fd558d18SJames Chapman { 233fd558d18SJames Chapman int hash; 234fd558d18SJames Chapman struct hlist_node *walk; 235fd558d18SJames Chapman struct l2tp_session *session; 236fd558d18SJames Chapman int count = 0; 237fd558d18SJames Chapman 238fd558d18SJames Chapman read_lock_bh(&tunnel->hlist_lock); 239fd558d18SJames Chapman for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 240fd558d18SJames Chapman hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { 241fd558d18SJames Chapman if (++count > nth) { 242fd558d18SJames Chapman read_unlock_bh(&tunnel->hlist_lock); 243fd558d18SJames Chapman return session; 244fd558d18SJames Chapman } 245fd558d18SJames Chapman } 246fd558d18SJames Chapman } 247fd558d18SJames Chapman 248fd558d18SJames Chapman read_unlock_bh(&tunnel->hlist_lock); 249fd558d18SJames Chapman 250fd558d18SJames Chapman return NULL; 251fd558d18SJames Chapman } 252fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_find_nth); 253fd558d18SJames Chapman 254309795f4SJames Chapman /* Lookup a session by interface name. 255309795f4SJames Chapman * This is very inefficient but is only used by management interfaces. 256309795f4SJames Chapman */ 257309795f4SJames Chapman struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname) 258309795f4SJames Chapman { 259309795f4SJames Chapman struct l2tp_net *pn = l2tp_pernet(net); 260309795f4SJames Chapman int hash; 261309795f4SJames Chapman struct hlist_node *walk; 262309795f4SJames Chapman struct l2tp_session *session; 263309795f4SJames Chapman 264e02d494dSJames Chapman rcu_read_lock_bh(); 265309795f4SJames Chapman for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { 266e02d494dSJames Chapman hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) { 267309795f4SJames Chapman if (!strcmp(session->ifname, ifname)) { 268e02d494dSJames Chapman rcu_read_unlock_bh(); 269309795f4SJames Chapman return session; 270309795f4SJames Chapman } 271309795f4SJames Chapman } 272309795f4SJames Chapman } 273309795f4SJames Chapman 274e02d494dSJames Chapman rcu_read_unlock_bh(); 275309795f4SJames Chapman 276309795f4SJames Chapman return NULL; 277309795f4SJames Chapman } 278309795f4SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname); 279309795f4SJames Chapman 280fd558d18SJames Chapman /* Lookup a tunnel by id 281fd558d18SJames Chapman */ 282fd558d18SJames Chapman struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) 283fd558d18SJames Chapman { 284fd558d18SJames Chapman struct l2tp_tunnel *tunnel; 285fd558d18SJames Chapman struct l2tp_net *pn = l2tp_pernet(net); 286fd558d18SJames Chapman 287e02d494dSJames Chapman rcu_read_lock_bh(); 288e02d494dSJames Chapman list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 289fd558d18SJames Chapman if (tunnel->tunnel_id == tunnel_id) { 290e02d494dSJames Chapman rcu_read_unlock_bh(); 291fd558d18SJames Chapman return tunnel; 292fd558d18SJames Chapman } 293fd558d18SJames Chapman } 294e02d494dSJames Chapman rcu_read_unlock_bh(); 295fd558d18SJames Chapman 296fd558d18SJames Chapman return NULL; 297fd558d18SJames Chapman } 298fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_tunnel_find); 299fd558d18SJames Chapman 300fd558d18SJames Chapman struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) 301fd558d18SJames Chapman { 302fd558d18SJames Chapman struct l2tp_net *pn = l2tp_pernet(net); 303fd558d18SJames Chapman struct l2tp_tunnel *tunnel; 304fd558d18SJames Chapman int count = 0; 305fd558d18SJames Chapman 306e02d494dSJames Chapman rcu_read_lock_bh(); 307e02d494dSJames Chapman list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { 308fd558d18SJames Chapman if (++count > nth) { 309e02d494dSJames Chapman rcu_read_unlock_bh(); 310fd558d18SJames Chapman return tunnel; 311fd558d18SJames Chapman } 312fd558d18SJames Chapman } 313fd558d18SJames Chapman 314e02d494dSJames Chapman rcu_read_unlock_bh(); 315fd558d18SJames Chapman 316fd558d18SJames Chapman return NULL; 317fd558d18SJames Chapman } 318fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); 319fd558d18SJames Chapman 320fd558d18SJames Chapman /***************************************************************************** 321fd558d18SJames Chapman * Receive data handling 322fd558d18SJames Chapman *****************************************************************************/ 323fd558d18SJames Chapman 324fd558d18SJames Chapman /* Queue a skb in order. We come here only if the skb has an L2TP sequence 325fd558d18SJames Chapman * number. 326fd558d18SJames Chapman */ 327fd558d18SJames Chapman static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) 328fd558d18SJames Chapman { 329fd558d18SJames Chapman struct sk_buff *skbp; 330fd558d18SJames Chapman struct sk_buff *tmp; 331f7faffa3SJames Chapman u32 ns = L2TP_SKB_CB(skb)->ns; 332fd558d18SJames Chapman 333fd558d18SJames Chapman spin_lock_bh(&session->reorder_q.lock); 334fd558d18SJames Chapman skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { 335fd558d18SJames Chapman if (L2TP_SKB_CB(skbp)->ns > ns) { 336fd558d18SJames Chapman __skb_queue_before(&session->reorder_q, skbp, skb); 337fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 338fd558d18SJames Chapman "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", 339fd558d18SJames Chapman session->name, ns, L2TP_SKB_CB(skbp)->ns, 340fd558d18SJames Chapman skb_queue_len(&session->reorder_q)); 341fd558d18SJames Chapman session->stats.rx_oos_packets++; 342fd558d18SJames Chapman goto out; 343fd558d18SJames Chapman } 344fd558d18SJames Chapman } 345fd558d18SJames Chapman 346fd558d18SJames Chapman __skb_queue_tail(&session->reorder_q, skb); 347fd558d18SJames Chapman 348fd558d18SJames Chapman out: 349fd558d18SJames Chapman spin_unlock_bh(&session->reorder_q.lock); 350fd558d18SJames Chapman } 351fd558d18SJames Chapman 352fd558d18SJames Chapman /* Dequeue a single skb. 353fd558d18SJames Chapman */ 354fd558d18SJames Chapman static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) 355fd558d18SJames Chapman { 356fd558d18SJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 357fd558d18SJames Chapman int length = L2TP_SKB_CB(skb)->length; 358fd558d18SJames Chapman 359fd558d18SJames Chapman /* We're about to requeue the skb, so return resources 360fd558d18SJames Chapman * to its current owner (a socket receive buffer). 361fd558d18SJames Chapman */ 362fd558d18SJames Chapman skb_orphan(skb); 363fd558d18SJames Chapman 364fd558d18SJames Chapman tunnel->stats.rx_packets++; 365fd558d18SJames Chapman tunnel->stats.rx_bytes += length; 366fd558d18SJames Chapman session->stats.rx_packets++; 367fd558d18SJames Chapman session->stats.rx_bytes += length; 368fd558d18SJames Chapman 369fd558d18SJames Chapman if (L2TP_SKB_CB(skb)->has_seq) { 370fd558d18SJames Chapman /* Bump our Nr */ 371fd558d18SJames Chapman session->nr++; 372f7faffa3SJames Chapman if (tunnel->version == L2TP_HDR_VER_2) 373f7faffa3SJames Chapman session->nr &= 0xffff; 374f7faffa3SJames Chapman else 375f7faffa3SJames Chapman session->nr &= 0xffffff; 376f7faffa3SJames Chapman 377fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 378fd558d18SJames Chapman "%s: updated nr to %hu\n", session->name, session->nr); 379fd558d18SJames Chapman } 380fd558d18SJames Chapman 381fd558d18SJames Chapman /* call private receive handler */ 382fd558d18SJames Chapman if (session->recv_skb != NULL) 383fd558d18SJames Chapman (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); 384fd558d18SJames Chapman else 385fd558d18SJames Chapman kfree_skb(skb); 386fd558d18SJames Chapman 387fd558d18SJames Chapman if (session->deref) 388fd558d18SJames Chapman (*session->deref)(session); 389fd558d18SJames Chapman } 390fd558d18SJames Chapman 391fd558d18SJames Chapman /* Dequeue skbs from the session's reorder_q, subject to packet order. 392fd558d18SJames Chapman * Skbs that have been in the queue for too long are simply discarded. 393fd558d18SJames Chapman */ 394fd558d18SJames Chapman static void l2tp_recv_dequeue(struct l2tp_session *session) 395fd558d18SJames Chapman { 396fd558d18SJames Chapman struct sk_buff *skb; 397fd558d18SJames Chapman struct sk_buff *tmp; 398fd558d18SJames Chapman 399fd558d18SJames Chapman /* If the pkt at the head of the queue has the nr that we 400fd558d18SJames Chapman * expect to send up next, dequeue it and any other 401fd558d18SJames Chapman * in-sequence packets behind it. 402fd558d18SJames Chapman */ 403e2e210c0SEric Dumazet start: 404fd558d18SJames Chapman spin_lock_bh(&session->reorder_q.lock); 405fd558d18SJames Chapman skb_queue_walk_safe(&session->reorder_q, skb, tmp) { 406fd558d18SJames Chapman if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { 407fd558d18SJames Chapman session->stats.rx_seq_discards++; 408fd558d18SJames Chapman session->stats.rx_errors++; 409fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 410f7faffa3SJames Chapman "%s: oos pkt %u len %d discarded (too old), " 411f7faffa3SJames Chapman "waiting for %u, reorder_q_len=%d\n", 412fd558d18SJames Chapman session->name, L2TP_SKB_CB(skb)->ns, 413fd558d18SJames Chapman L2TP_SKB_CB(skb)->length, session->nr, 414fd558d18SJames Chapman skb_queue_len(&session->reorder_q)); 415fd558d18SJames Chapman __skb_unlink(skb, &session->reorder_q); 416fd558d18SJames Chapman kfree_skb(skb); 417fd558d18SJames Chapman if (session->deref) 418fd558d18SJames Chapman (*session->deref)(session); 419fd558d18SJames Chapman continue; 420fd558d18SJames Chapman } 421fd558d18SJames Chapman 422fd558d18SJames Chapman if (L2TP_SKB_CB(skb)->has_seq) { 423fd558d18SJames Chapman if (L2TP_SKB_CB(skb)->ns != session->nr) { 424fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 425f7faffa3SJames Chapman "%s: holding oos pkt %u len %d, " 426f7faffa3SJames Chapman "waiting for %u, reorder_q_len=%d\n", 427fd558d18SJames Chapman session->name, L2TP_SKB_CB(skb)->ns, 428fd558d18SJames Chapman L2TP_SKB_CB(skb)->length, session->nr, 429fd558d18SJames Chapman skb_queue_len(&session->reorder_q)); 430fd558d18SJames Chapman goto out; 431fd558d18SJames Chapman } 432fd558d18SJames Chapman } 433fd558d18SJames Chapman __skb_unlink(skb, &session->reorder_q); 434fd558d18SJames Chapman 435fd558d18SJames Chapman /* Process the skb. We release the queue lock while we 436fd558d18SJames Chapman * do so to let other contexts process the queue. 437fd558d18SJames Chapman */ 438fd558d18SJames Chapman spin_unlock_bh(&session->reorder_q.lock); 439fd558d18SJames Chapman l2tp_recv_dequeue_skb(session, skb); 440e2e210c0SEric Dumazet goto start; 441fd558d18SJames Chapman } 442fd558d18SJames Chapman 443fd558d18SJames Chapman out: 444fd558d18SJames Chapman spin_unlock_bh(&session->reorder_q.lock); 445fd558d18SJames Chapman } 446fd558d18SJames Chapman 447fd558d18SJames Chapman static inline int l2tp_verify_udp_checksum(struct sock *sk, 448fd558d18SJames Chapman struct sk_buff *skb) 449fd558d18SJames Chapman { 450fd558d18SJames Chapman struct udphdr *uh = udp_hdr(skb); 451fd558d18SJames Chapman u16 ulen = ntohs(uh->len); 452fd558d18SJames Chapman __wsum psum; 453fd558d18SJames Chapman 454d2cf3361SBenjamin LaHaise if (sk->sk_no_check || skb_csum_unnecessary(skb)) 455fd558d18SJames Chapman return 0; 456fd558d18SJames Chapman 457d2cf3361SBenjamin LaHaise #if IS_ENABLED(CONFIG_IPV6) 458d2cf3361SBenjamin LaHaise if (sk->sk_family == PF_INET6) { 459d2cf3361SBenjamin LaHaise if (!uh->check) { 460d2cf3361SBenjamin LaHaise LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n"); 461d2cf3361SBenjamin LaHaise return 1; 462d2cf3361SBenjamin LaHaise } 463d2cf3361SBenjamin LaHaise if ((skb->ip_summed == CHECKSUM_COMPLETE) && 464d2cf3361SBenjamin LaHaise !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, 465d2cf3361SBenjamin LaHaise &ipv6_hdr(skb)->daddr, ulen, 466d2cf3361SBenjamin LaHaise IPPROTO_UDP, skb->csum)) { 467d2cf3361SBenjamin LaHaise skb->ip_summed = CHECKSUM_UNNECESSARY; 468d2cf3361SBenjamin LaHaise return 0; 469d2cf3361SBenjamin LaHaise } 470d2cf3361SBenjamin LaHaise skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr, 471d2cf3361SBenjamin LaHaise &ipv6_hdr(skb)->daddr, 472d2cf3361SBenjamin LaHaise skb->len, IPPROTO_UDP, 473d2cf3361SBenjamin LaHaise 0)); 474d2cf3361SBenjamin LaHaise } else 475d2cf3361SBenjamin LaHaise #endif 476d2cf3361SBenjamin LaHaise { 477d2cf3361SBenjamin LaHaise struct inet_sock *inet; 478d2cf3361SBenjamin LaHaise if (!uh->check) 479d2cf3361SBenjamin LaHaise return 0; 480fd558d18SJames Chapman inet = inet_sk(sk); 481d2cf3361SBenjamin LaHaise psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, 482d2cf3361SBenjamin LaHaise ulen, IPPROTO_UDP, 0); 483fd558d18SJames Chapman 484fd558d18SJames Chapman if ((skb->ip_summed == CHECKSUM_COMPLETE) && 485fd558d18SJames Chapman !csum_fold(csum_add(psum, skb->csum))) 486fd558d18SJames Chapman return 0; 487fd558d18SJames Chapman skb->csum = psum; 488d2cf3361SBenjamin LaHaise } 489fd558d18SJames Chapman 490fd558d18SJames Chapman return __skb_checksum_complete(skb); 491fd558d18SJames Chapman } 492fd558d18SJames Chapman 493f7faffa3SJames Chapman /* Do receive processing of L2TP data frames. We handle both L2TPv2 494f7faffa3SJames Chapman * and L2TPv3 data frames here. 495f7faffa3SJames Chapman * 496f7faffa3SJames Chapman * L2TPv2 Data Message Header 497f7faffa3SJames Chapman * 498f7faffa3SJames Chapman * 0 1 2 3 499f7faffa3SJames Chapman * 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 500f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 501f7faffa3SJames Chapman * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | 502f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 503f7faffa3SJames Chapman * | Tunnel ID | Session ID | 504f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 505f7faffa3SJames Chapman * | Ns (opt) | Nr (opt) | 506f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 507f7faffa3SJames Chapman * | Offset Size (opt) | Offset pad... (opt) 508f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 509f7faffa3SJames Chapman * 510f7faffa3SJames Chapman * Data frames are marked by T=0. All other fields are the same as 511f7faffa3SJames Chapman * those in L2TP control frames. 512f7faffa3SJames Chapman * 513f7faffa3SJames Chapman * L2TPv3 Data Message Header 514f7faffa3SJames Chapman * 515f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516f7faffa3SJames Chapman * | L2TP Session Header | 517f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 518f7faffa3SJames Chapman * | L2-Specific Sublayer | 519f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 520f7faffa3SJames Chapman * | Tunnel Payload ... 521f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 522f7faffa3SJames Chapman * 523f7faffa3SJames Chapman * L2TPv3 Session Header Over IP 524f7faffa3SJames Chapman * 525f7faffa3SJames Chapman * 0 1 2 3 526f7faffa3SJames Chapman * 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 527f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 528f7faffa3SJames Chapman * | Session ID | 529f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 530f7faffa3SJames Chapman * | Cookie (optional, maximum 64 bits)... 531f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532f7faffa3SJames Chapman * | 533f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 534f7faffa3SJames Chapman * 535f7faffa3SJames Chapman * L2TPv3 L2-Specific Sublayer Format 536f7faffa3SJames Chapman * 537f7faffa3SJames Chapman * 0 1 2 3 538f7faffa3SJames Chapman * 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 539f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 540f7faffa3SJames Chapman * |x|S|x|x|x|x|x|x| Sequence Number | 541f7faffa3SJames Chapman * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 542f7faffa3SJames Chapman * 543f7faffa3SJames Chapman * Cookie value, sublayer format and offset (pad) are negotiated with 544f7faffa3SJames Chapman * the peer when the session is set up. Unlike L2TPv2, we do not need 545f7faffa3SJames Chapman * to parse the packet header to determine if optional fields are 546f7faffa3SJames Chapman * present. 547f7faffa3SJames Chapman * 548f7faffa3SJames Chapman * Caller must already have parsed the frame and determined that it is 549f7faffa3SJames Chapman * a data (not control) frame before coming here. Fields up to the 550f7faffa3SJames Chapman * session-id have already been parsed and ptr points to the data 551f7faffa3SJames Chapman * after the session-id. 552f7faffa3SJames Chapman */ 553f7faffa3SJames Chapman void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, 554f7faffa3SJames Chapman unsigned char *ptr, unsigned char *optr, u16 hdrflags, 555f7faffa3SJames Chapman int length, int (*payload_hook)(struct sk_buff *skb)) 556f7faffa3SJames Chapman { 557f7faffa3SJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 558f7faffa3SJames Chapman int offset; 559f7faffa3SJames Chapman u32 ns, nr; 560f7faffa3SJames Chapman 561f7faffa3SJames Chapman /* The ref count is increased since we now hold a pointer to 562f7faffa3SJames Chapman * the session. Take care to decrement the refcnt when exiting 563f7faffa3SJames Chapman * this function from now on... 564f7faffa3SJames Chapman */ 565f7faffa3SJames Chapman l2tp_session_inc_refcount(session); 566f7faffa3SJames Chapman if (session->ref) 567f7faffa3SJames Chapman (*session->ref)(session); 568f7faffa3SJames Chapman 569f7faffa3SJames Chapman /* Parse and check optional cookie */ 570f7faffa3SJames Chapman if (session->peer_cookie_len > 0) { 571f7faffa3SJames Chapman if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { 572f7faffa3SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 573f7faffa3SJames Chapman "%s: cookie mismatch (%u/%u). Discarding.\n", 574f7faffa3SJames Chapman tunnel->name, tunnel->tunnel_id, session->session_id); 575f7faffa3SJames Chapman session->stats.rx_cookie_discards++; 576f7faffa3SJames Chapman goto discard; 577f7faffa3SJames Chapman } 578f7faffa3SJames Chapman ptr += session->peer_cookie_len; 579f7faffa3SJames Chapman } 580f7faffa3SJames Chapman 581f7faffa3SJames Chapman /* Handle the optional sequence numbers. Sequence numbers are 582f7faffa3SJames Chapman * in different places for L2TPv2 and L2TPv3. 583f7faffa3SJames Chapman * 584f7faffa3SJames Chapman * If we are the LAC, enable/disable sequence numbers under 585f7faffa3SJames Chapman * the control of the LNS. If no sequence numbers present but 586f7faffa3SJames Chapman * we were expecting them, discard frame. 587f7faffa3SJames Chapman */ 588f7faffa3SJames Chapman ns = nr = 0; 589f7faffa3SJames Chapman L2TP_SKB_CB(skb)->has_seq = 0; 590f7faffa3SJames Chapman if (tunnel->version == L2TP_HDR_VER_2) { 591f7faffa3SJames Chapman if (hdrflags & L2TP_HDRFLAG_S) { 592f7faffa3SJames Chapman ns = ntohs(*(__be16 *) ptr); 593f7faffa3SJames Chapman ptr += 2; 594f7faffa3SJames Chapman nr = ntohs(*(__be16 *) ptr); 595f7faffa3SJames Chapman ptr += 2; 596f7faffa3SJames Chapman 597f7faffa3SJames Chapman /* Store L2TP info in the skb */ 598f7faffa3SJames Chapman L2TP_SKB_CB(skb)->ns = ns; 599f7faffa3SJames Chapman L2TP_SKB_CB(skb)->has_seq = 1; 600f7faffa3SJames Chapman 601f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 602f7faffa3SJames Chapman "%s: recv data ns=%u, nr=%u, session nr=%u\n", 603f7faffa3SJames Chapman session->name, ns, nr, session->nr); 604f7faffa3SJames Chapman } 605f7faffa3SJames Chapman } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 606f7faffa3SJames Chapman u32 l2h = ntohl(*(__be32 *) ptr); 607f7faffa3SJames Chapman 608f7faffa3SJames Chapman if (l2h & 0x40000000) { 609f7faffa3SJames Chapman ns = l2h & 0x00ffffff; 610f7faffa3SJames Chapman 611f7faffa3SJames Chapman /* Store L2TP info in the skb */ 612f7faffa3SJames Chapman L2TP_SKB_CB(skb)->ns = ns; 613f7faffa3SJames Chapman L2TP_SKB_CB(skb)->has_seq = 1; 614f7faffa3SJames Chapman 615f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 616f7faffa3SJames Chapman "%s: recv data ns=%u, session nr=%u\n", 617f7faffa3SJames Chapman session->name, ns, session->nr); 618f7faffa3SJames Chapman } 619f7faffa3SJames Chapman } 620f7faffa3SJames Chapman 621f7faffa3SJames Chapman /* Advance past L2-specific header, if present */ 622f7faffa3SJames Chapman ptr += session->l2specific_len; 623f7faffa3SJames Chapman 624f7faffa3SJames Chapman if (L2TP_SKB_CB(skb)->has_seq) { 625f7faffa3SJames Chapman /* Received a packet with sequence numbers. If we're the LNS, 626f7faffa3SJames Chapman * check if we sre sending sequence numbers and if not, 627f7faffa3SJames Chapman * configure it so. 628f7faffa3SJames Chapman */ 629f7faffa3SJames Chapman if ((!session->lns_mode) && (!session->send_seq)) { 630f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, 631f7faffa3SJames Chapman "%s: requested to enable seq numbers by LNS\n", 632f7faffa3SJames Chapman session->name); 633f7faffa3SJames Chapman session->send_seq = -1; 634f7faffa3SJames Chapman l2tp_session_set_header_len(session, tunnel->version); 635f7faffa3SJames Chapman } 636f7faffa3SJames Chapman } else { 637f7faffa3SJames Chapman /* No sequence numbers. 638f7faffa3SJames Chapman * If user has configured mandatory sequence numbers, discard. 639f7faffa3SJames Chapman */ 640f7faffa3SJames Chapman if (session->recv_seq) { 641f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, 642f7faffa3SJames Chapman "%s: recv data has no seq numbers when required. " 643f7faffa3SJames Chapman "Discarding\n", session->name); 644f7faffa3SJames Chapman session->stats.rx_seq_discards++; 645f7faffa3SJames Chapman goto discard; 646f7faffa3SJames Chapman } 647f7faffa3SJames Chapman 648f7faffa3SJames Chapman /* If we're the LAC and we're sending sequence numbers, the 649f7faffa3SJames Chapman * LNS has requested that we no longer send sequence numbers. 650f7faffa3SJames Chapman * If we're the LNS and we're sending sequence numbers, the 651f7faffa3SJames Chapman * LAC is broken. Discard the frame. 652f7faffa3SJames Chapman */ 653f7faffa3SJames Chapman if ((!session->lns_mode) && (session->send_seq)) { 654f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO, 655f7faffa3SJames Chapman "%s: requested to disable seq numbers by LNS\n", 656f7faffa3SJames Chapman session->name); 657f7faffa3SJames Chapman session->send_seq = 0; 658f7faffa3SJames Chapman l2tp_session_set_header_len(session, tunnel->version); 659f7faffa3SJames Chapman } else if (session->send_seq) { 660f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, 661f7faffa3SJames Chapman "%s: recv data has no seq numbers when required. " 662f7faffa3SJames Chapman "Discarding\n", session->name); 663f7faffa3SJames Chapman session->stats.rx_seq_discards++; 664f7faffa3SJames Chapman goto discard; 665f7faffa3SJames Chapman } 666f7faffa3SJames Chapman } 667f7faffa3SJames Chapman 668f7faffa3SJames Chapman /* Session data offset is handled differently for L2TPv2 and 669f7faffa3SJames Chapman * L2TPv3. For L2TPv2, there is an optional 16-bit value in 670f7faffa3SJames Chapman * the header. For L2TPv3, the offset is negotiated using AVPs 671f7faffa3SJames Chapman * in the session setup control protocol. 672f7faffa3SJames Chapman */ 673f7faffa3SJames Chapman if (tunnel->version == L2TP_HDR_VER_2) { 674f7faffa3SJames Chapman /* If offset bit set, skip it. */ 675f7faffa3SJames Chapman if (hdrflags & L2TP_HDRFLAG_O) { 676f7faffa3SJames Chapman offset = ntohs(*(__be16 *)ptr); 677f7faffa3SJames Chapman ptr += 2 + offset; 678f7faffa3SJames Chapman } 679f7faffa3SJames Chapman } else 680f7faffa3SJames Chapman ptr += session->offset; 681f7faffa3SJames Chapman 682f7faffa3SJames Chapman offset = ptr - optr; 683f7faffa3SJames Chapman if (!pskb_may_pull(skb, offset)) 684f7faffa3SJames Chapman goto discard; 685f7faffa3SJames Chapman 686f7faffa3SJames Chapman __skb_pull(skb, offset); 687f7faffa3SJames Chapman 688f7faffa3SJames Chapman /* If caller wants to process the payload before we queue the 689f7faffa3SJames Chapman * packet, do so now. 690f7faffa3SJames Chapman */ 691f7faffa3SJames Chapman if (payload_hook) 692f7faffa3SJames Chapman if ((*payload_hook)(skb)) 693f7faffa3SJames Chapman goto discard; 694f7faffa3SJames Chapman 695f7faffa3SJames Chapman /* Prepare skb for adding to the session's reorder_q. Hold 696f7faffa3SJames Chapman * packets for max reorder_timeout or 1 second if not 697f7faffa3SJames Chapman * reordering. 698f7faffa3SJames Chapman */ 699f7faffa3SJames Chapman L2TP_SKB_CB(skb)->length = length; 700f7faffa3SJames Chapman L2TP_SKB_CB(skb)->expires = jiffies + 701f7faffa3SJames Chapman (session->reorder_timeout ? session->reorder_timeout : HZ); 702f7faffa3SJames Chapman 703f7faffa3SJames Chapman /* Add packet to the session's receive queue. Reordering is done here, if 704f7faffa3SJames Chapman * enabled. Saved L2TP protocol info is stored in skb->sb[]. 705f7faffa3SJames Chapman */ 706f7faffa3SJames Chapman if (L2TP_SKB_CB(skb)->has_seq) { 707f7faffa3SJames Chapman if (session->reorder_timeout != 0) { 708f7faffa3SJames Chapman /* Packet reordering enabled. Add skb to session's 709f7faffa3SJames Chapman * reorder queue, in order of ns. 710f7faffa3SJames Chapman */ 711f7faffa3SJames Chapman l2tp_recv_queue_skb(session, skb); 712f7faffa3SJames Chapman } else { 713f7faffa3SJames Chapman /* Packet reordering disabled. Discard out-of-sequence 714f7faffa3SJames Chapman * packets 715f7faffa3SJames Chapman */ 716f7faffa3SJames Chapman if (L2TP_SKB_CB(skb)->ns != session->nr) { 717f7faffa3SJames Chapman session->stats.rx_seq_discards++; 718f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 719f7faffa3SJames Chapman "%s: oos pkt %u len %d discarded, " 720f7faffa3SJames Chapman "waiting for %u, reorder_q_len=%d\n", 721f7faffa3SJames Chapman session->name, L2TP_SKB_CB(skb)->ns, 722f7faffa3SJames Chapman L2TP_SKB_CB(skb)->length, session->nr, 723f7faffa3SJames Chapman skb_queue_len(&session->reorder_q)); 724f7faffa3SJames Chapman goto discard; 725f7faffa3SJames Chapman } 726f7faffa3SJames Chapman skb_queue_tail(&session->reorder_q, skb); 727f7faffa3SJames Chapman } 728f7faffa3SJames Chapman } else { 729f7faffa3SJames Chapman /* No sequence numbers. Add the skb to the tail of the 730f7faffa3SJames Chapman * reorder queue. This ensures that it will be 731f7faffa3SJames Chapman * delivered after all previous sequenced skbs. 732f7faffa3SJames Chapman */ 733f7faffa3SJames Chapman skb_queue_tail(&session->reorder_q, skb); 734f7faffa3SJames Chapman } 735f7faffa3SJames Chapman 736f7faffa3SJames Chapman /* Try to dequeue as many skbs from reorder_q as we can. */ 737f7faffa3SJames Chapman l2tp_recv_dequeue(session); 738f7faffa3SJames Chapman 739f7faffa3SJames Chapman l2tp_session_dec_refcount(session); 740f7faffa3SJames Chapman 741f7faffa3SJames Chapman return; 742f7faffa3SJames Chapman 743f7faffa3SJames Chapman discard: 744f7faffa3SJames Chapman session->stats.rx_errors++; 745f7faffa3SJames Chapman kfree_skb(skb); 746f7faffa3SJames Chapman 747f7faffa3SJames Chapman if (session->deref) 748f7faffa3SJames Chapman (*session->deref)(session); 749f7faffa3SJames Chapman 750f7faffa3SJames Chapman l2tp_session_dec_refcount(session); 751f7faffa3SJames Chapman } 752f7faffa3SJames Chapman EXPORT_SYMBOL(l2tp_recv_common); 753f7faffa3SJames Chapman 754fd558d18SJames Chapman /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame 755fd558d18SJames Chapman * here. The skb is not on a list when we get here. 756fd558d18SJames Chapman * Returns 0 if the packet was a data packet and was successfully passed on. 757fd558d18SJames Chapman * Returns 1 if the packet was not a good data packet and could not be 758fd558d18SJames Chapman * forwarded. All such packets are passed up to userspace to deal with. 759fd558d18SJames Chapman */ 760fc130840Sstephen hemminger static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, 761fd558d18SJames Chapman int (*payload_hook)(struct sk_buff *skb)) 762fd558d18SJames Chapman { 763fd558d18SJames Chapman struct l2tp_session *session = NULL; 764fd558d18SJames Chapman unsigned char *ptr, *optr; 765fd558d18SJames Chapman u16 hdrflags; 766fd558d18SJames Chapman u32 tunnel_id, session_id; 767fd558d18SJames Chapman int offset; 768fd558d18SJames Chapman u16 version; 769f7faffa3SJames Chapman int length; 770fd558d18SJames Chapman 771fd558d18SJames Chapman if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb)) 772fd558d18SJames Chapman goto discard_bad_csum; 773fd558d18SJames Chapman 774fd558d18SJames Chapman /* UDP always verifies the packet length. */ 775fd558d18SJames Chapman __skb_pull(skb, sizeof(struct udphdr)); 776fd558d18SJames Chapman 777fd558d18SJames Chapman /* Short packet? */ 778fd558d18SJames Chapman if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { 779fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 780fd558d18SJames Chapman "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); 781fd558d18SJames Chapman goto error; 782fd558d18SJames Chapman } 783fd558d18SJames Chapman 784fd558d18SJames Chapman /* Trace packet contents, if enabled */ 785fd558d18SJames Chapman if (tunnel->debug & L2TP_MSG_DATA) { 786fd558d18SJames Chapman length = min(32u, skb->len); 787fd558d18SJames Chapman if (!pskb_may_pull(skb, length)) 788fd558d18SJames Chapman goto error; 789fd558d18SJames Chapman 790fd558d18SJames Chapman printk(KERN_DEBUG "%s: recv: ", tunnel->name); 791fd558d18SJames Chapman 792fd558d18SJames Chapman offset = 0; 793fd558d18SJames Chapman do { 794e50e705cSEric Dumazet printk(" %02X", skb->data[offset]); 795fd558d18SJames Chapman } while (++offset < length); 796fd558d18SJames Chapman 797fd558d18SJames Chapman printk("\n"); 798fd558d18SJames Chapman } 799fd558d18SJames Chapman 800e50e705cSEric Dumazet /* Point to L2TP header */ 801e50e705cSEric Dumazet optr = ptr = skb->data; 802e50e705cSEric Dumazet 803fd558d18SJames Chapman /* Get L2TP header flags */ 804fd558d18SJames Chapman hdrflags = ntohs(*(__be16 *) ptr); 805fd558d18SJames Chapman 806fd558d18SJames Chapman /* Check protocol version */ 807fd558d18SJames Chapman version = hdrflags & L2TP_HDR_VER_MASK; 808fd558d18SJames Chapman if (version != tunnel->version) { 809fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 810fd558d18SJames Chapman "%s: recv protocol version mismatch: got %d expected %d\n", 811fd558d18SJames Chapman tunnel->name, version, tunnel->version); 812fd558d18SJames Chapman goto error; 813fd558d18SJames Chapman } 814fd558d18SJames Chapman 815fd558d18SJames Chapman /* Get length of L2TP packet */ 816fd558d18SJames Chapman length = skb->len; 817fd558d18SJames Chapman 818fd558d18SJames Chapman /* If type is control packet, it is handled by userspace. */ 819fd558d18SJames Chapman if (hdrflags & L2TP_HDRFLAG_T) { 820fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, 821fd558d18SJames Chapman "%s: recv control packet, len=%d\n", tunnel->name, length); 822fd558d18SJames Chapman goto error; 823fd558d18SJames Chapman } 824fd558d18SJames Chapman 825fd558d18SJames Chapman /* Skip flags */ 826fd558d18SJames Chapman ptr += 2; 827fd558d18SJames Chapman 828f7faffa3SJames Chapman if (tunnel->version == L2TP_HDR_VER_2) { 829fd558d18SJames Chapman /* If length is present, skip it */ 830fd558d18SJames Chapman if (hdrflags & L2TP_HDRFLAG_L) 831fd558d18SJames Chapman ptr += 2; 832fd558d18SJames Chapman 833fd558d18SJames Chapman /* Extract tunnel and session ID */ 834fd558d18SJames Chapman tunnel_id = ntohs(*(__be16 *) ptr); 835fd558d18SJames Chapman ptr += 2; 836fd558d18SJames Chapman session_id = ntohs(*(__be16 *) ptr); 837fd558d18SJames Chapman ptr += 2; 838f7faffa3SJames Chapman } else { 839f7faffa3SJames Chapman ptr += 2; /* skip reserved bits */ 840f7faffa3SJames Chapman tunnel_id = tunnel->tunnel_id; 841f7faffa3SJames Chapman session_id = ntohl(*(__be32 *) ptr); 842f7faffa3SJames Chapman ptr += 4; 843f7faffa3SJames Chapman } 844fd558d18SJames Chapman 845fd558d18SJames Chapman /* Find the session context */ 846f7faffa3SJames Chapman session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id); 847309795f4SJames Chapman if (!session || !session->recv_skb) { 848fd558d18SJames Chapman /* Not found? Pass to userspace to deal with */ 849fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, 850f7faffa3SJames Chapman "%s: no session found (%u/%u). Passing up.\n", 851fd558d18SJames Chapman tunnel->name, tunnel_id, session_id); 852fd558d18SJames Chapman goto error; 853fd558d18SJames Chapman } 854fd558d18SJames Chapman 855f7faffa3SJames Chapman l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); 856fd558d18SJames Chapman 857fd558d18SJames Chapman return 0; 858fd558d18SJames Chapman 859fd558d18SJames Chapman discard_bad_csum: 860fd558d18SJames Chapman LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); 861fd558d18SJames Chapman UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); 862fd558d18SJames Chapman tunnel->stats.rx_errors++; 863fd558d18SJames Chapman kfree_skb(skb); 864fd558d18SJames Chapman 865fd558d18SJames Chapman return 0; 866fd558d18SJames Chapman 867fd558d18SJames Chapman error: 868fd558d18SJames Chapman /* Put UDP header back */ 869fd558d18SJames Chapman __skb_push(skb, sizeof(struct udphdr)); 870fd558d18SJames Chapman 871fd558d18SJames Chapman return 1; 872fd558d18SJames Chapman } 873fd558d18SJames Chapman 874fd558d18SJames Chapman /* UDP encapsulation receive handler. See net/ipv4/udp.c. 875fd558d18SJames Chapman * Return codes: 876fd558d18SJames Chapman * 0 : success. 877fd558d18SJames Chapman * <0: error 878fd558d18SJames Chapman * >0: skb should be passed up to userspace as UDP. 879fd558d18SJames Chapman */ 880fd558d18SJames Chapman int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) 881fd558d18SJames Chapman { 882fd558d18SJames Chapman struct l2tp_tunnel *tunnel; 883fd558d18SJames Chapman 884fd558d18SJames Chapman tunnel = l2tp_sock_to_tunnel(sk); 885fd558d18SJames Chapman if (tunnel == NULL) 886fd558d18SJames Chapman goto pass_up; 887fd558d18SJames Chapman 888fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, 889fd558d18SJames Chapman "%s: received %d bytes\n", tunnel->name, skb->len); 890fd558d18SJames Chapman 891fd558d18SJames Chapman if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) 892fd558d18SJames Chapman goto pass_up_put; 893fd558d18SJames Chapman 894fd558d18SJames Chapman sock_put(sk); 895fd558d18SJames Chapman return 0; 896fd558d18SJames Chapman 897fd558d18SJames Chapman pass_up_put: 898fd558d18SJames Chapman sock_put(sk); 899fd558d18SJames Chapman pass_up: 900fd558d18SJames Chapman return 1; 901fd558d18SJames Chapman } 902fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); 903fd558d18SJames Chapman 904fd558d18SJames Chapman /************************************************************************ 905fd558d18SJames Chapman * Transmit handling 906fd558d18SJames Chapman ***********************************************************************/ 907fd558d18SJames Chapman 908fd558d18SJames Chapman /* Build an L2TP header for the session into the buffer provided. 909fd558d18SJames Chapman */ 910f7faffa3SJames Chapman static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) 911fd558d18SJames Chapman { 912f7faffa3SJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 913fd558d18SJames Chapman __be16 *bufp = buf; 914f7faffa3SJames Chapman __be16 *optr = buf; 915fd558d18SJames Chapman u16 flags = L2TP_HDR_VER_2; 916fd558d18SJames Chapman u32 tunnel_id = tunnel->peer_tunnel_id; 917fd558d18SJames Chapman u32 session_id = session->peer_session_id; 918fd558d18SJames Chapman 919fd558d18SJames Chapman if (session->send_seq) 920fd558d18SJames Chapman flags |= L2TP_HDRFLAG_S; 921fd558d18SJames Chapman 922fd558d18SJames Chapman /* Setup L2TP header. */ 923fd558d18SJames Chapman *bufp++ = htons(flags); 924fd558d18SJames Chapman *bufp++ = htons(tunnel_id); 925fd558d18SJames Chapman *bufp++ = htons(session_id); 926fd558d18SJames Chapman if (session->send_seq) { 927fd558d18SJames Chapman *bufp++ = htons(session->ns); 928fd558d18SJames Chapman *bufp++ = 0; 929fd558d18SJames Chapman session->ns++; 930f7faffa3SJames Chapman session->ns &= 0xffff; 931fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 932f7faffa3SJames Chapman "%s: updated ns to %u\n", session->name, session->ns); 933fd558d18SJames Chapman } 934fd558d18SJames Chapman 935f7faffa3SJames Chapman return bufp - optr; 936f7faffa3SJames Chapman } 937f7faffa3SJames Chapman 938f7faffa3SJames Chapman static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 939fd558d18SJames Chapman { 9400d76751fSJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 941f7faffa3SJames Chapman char *bufp = buf; 942f7faffa3SJames Chapman char *optr = bufp; 943fd558d18SJames Chapman 9440d76751fSJames Chapman /* Setup L2TP header. The header differs slightly for UDP and 9450d76751fSJames Chapman * IP encapsulations. For UDP, there is 4 bytes of flags. 9460d76751fSJames Chapman */ 9470d76751fSJames Chapman if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 9480d76751fSJames Chapman u16 flags = L2TP_HDR_VER_3; 949f7faffa3SJames Chapman *((__be16 *) bufp) = htons(flags); 950f7faffa3SJames Chapman bufp += 2; 951f7faffa3SJames Chapman *((__be16 *) bufp) = 0; 952f7faffa3SJames Chapman bufp += 2; 9530d76751fSJames Chapman } 9540d76751fSJames Chapman 955f7faffa3SJames Chapman *((__be32 *) bufp) = htonl(session->peer_session_id); 956f7faffa3SJames Chapman bufp += 4; 957f7faffa3SJames Chapman if (session->cookie_len) { 958f7faffa3SJames Chapman memcpy(bufp, &session->cookie[0], session->cookie_len); 959f7faffa3SJames Chapman bufp += session->cookie_len; 960fd558d18SJames Chapman } 961f7faffa3SJames Chapman if (session->l2specific_len) { 962f7faffa3SJames Chapman if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { 963f7faffa3SJames Chapman u32 l2h = 0; 964f7faffa3SJames Chapman if (session->send_seq) { 965f7faffa3SJames Chapman l2h = 0x40000000 | session->ns; 966f7faffa3SJames Chapman session->ns++; 967f7faffa3SJames Chapman session->ns &= 0xffffff; 968f7faffa3SJames Chapman PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, 969f7faffa3SJames Chapman "%s: updated ns to %u\n", session->name, session->ns); 970f7faffa3SJames Chapman } 971f7faffa3SJames Chapman 972f7faffa3SJames Chapman *((__be32 *) bufp) = htonl(l2h); 973f7faffa3SJames Chapman } 974f7faffa3SJames Chapman bufp += session->l2specific_len; 975f7faffa3SJames Chapman } 976f7faffa3SJames Chapman if (session->offset) 977f7faffa3SJames Chapman bufp += session->offset; 978f7faffa3SJames Chapman 979f7faffa3SJames Chapman return bufp - optr; 980f7faffa3SJames Chapman } 981fd558d18SJames Chapman 982fc130840Sstephen hemminger static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, 983d9d8da80SDavid S. Miller struct flowi *fl, size_t data_len) 984fd558d18SJames Chapman { 985fd558d18SJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 986fd558d18SJames Chapman unsigned int len = skb->len; 987fd558d18SJames Chapman int error; 988fd558d18SJames Chapman 989fd558d18SJames Chapman /* Debug */ 990fd558d18SJames Chapman if (session->send_seq) 991fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, 992f7faffa3SJames Chapman "%s: send %Zd bytes, ns=%u\n", session->name, 993fd558d18SJames Chapman data_len, session->ns - 1); 994fd558d18SJames Chapman else 995fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, 996fd558d18SJames Chapman "%s: send %Zd bytes\n", session->name, data_len); 997fd558d18SJames Chapman 998fd558d18SJames Chapman if (session->debug & L2TP_MSG_DATA) { 999fd558d18SJames Chapman int i; 10000d76751fSJames Chapman int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 10010d76751fSJames Chapman unsigned char *datap = skb->data + uhlen; 1002fd558d18SJames Chapman 1003fd558d18SJames Chapman printk(KERN_DEBUG "%s: xmit:", session->name); 10040d76751fSJames Chapman for (i = 0; i < (len - uhlen); i++) { 1005fd558d18SJames Chapman printk(" %02X", *datap++); 1006fd558d18SJames Chapman if (i == 31) { 1007fd558d18SJames Chapman printk(" ..."); 1008fd558d18SJames Chapman break; 1009fd558d18SJames Chapman } 1010fd558d18SJames Chapman } 1011fd558d18SJames Chapman printk("\n"); 1012fd558d18SJames Chapman } 1013fd558d18SJames Chapman 1014fd558d18SJames Chapman /* Queue the packet to IP for output */ 10154e15ed4dSShan Wei skb->local_df = 1; 1016d2cf3361SBenjamin LaHaise #if IS_ENABLED(CONFIG_IPV6) 1017d2cf3361SBenjamin LaHaise if (skb->sk->sk_family == PF_INET6) 1018d2cf3361SBenjamin LaHaise error = inet6_csk_xmit(skb, NULL); 1019d2cf3361SBenjamin LaHaise else 1020d2cf3361SBenjamin LaHaise #endif 1021d9d8da80SDavid S. Miller error = ip_queue_xmit(skb, fl); 1022fd558d18SJames Chapman 1023fd558d18SJames Chapman /* Update stats */ 1024fd558d18SJames Chapman if (error >= 0) { 1025fd558d18SJames Chapman tunnel->stats.tx_packets++; 1026fd558d18SJames Chapman tunnel->stats.tx_bytes += len; 1027fd558d18SJames Chapman session->stats.tx_packets++; 1028fd558d18SJames Chapman session->stats.tx_bytes += len; 1029fd558d18SJames Chapman } else { 1030fd558d18SJames Chapman tunnel->stats.tx_errors++; 1031fd558d18SJames Chapman session->stats.tx_errors++; 1032fd558d18SJames Chapman } 1033fd558d18SJames Chapman 1034fd558d18SJames Chapman return 0; 1035fd558d18SJames Chapman } 1036fd558d18SJames Chapman 1037fd558d18SJames Chapman /* Automatically called when the skb is freed. 1038fd558d18SJames Chapman */ 1039fd558d18SJames Chapman static void l2tp_sock_wfree(struct sk_buff *skb) 1040fd558d18SJames Chapman { 1041fd558d18SJames Chapman sock_put(skb->sk); 1042fd558d18SJames Chapman } 1043fd558d18SJames Chapman 1044fd558d18SJames Chapman /* For data skbs that we transmit, we associate with the tunnel socket 1045fd558d18SJames Chapman * but don't do accounting. 1046fd558d18SJames Chapman */ 1047fd558d18SJames Chapman static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) 1048fd558d18SJames Chapman { 1049fd558d18SJames Chapman sock_hold(sk); 1050fd558d18SJames Chapman skb->sk = sk; 1051fd558d18SJames Chapman skb->destructor = l2tp_sock_wfree; 1052fd558d18SJames Chapman } 1053fd558d18SJames Chapman 1054d2cf3361SBenjamin LaHaise #if IS_ENABLED(CONFIG_IPV6) 1055d2cf3361SBenjamin LaHaise static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb, 1056d2cf3361SBenjamin LaHaise int udp_len) 1057d2cf3361SBenjamin LaHaise { 1058d2cf3361SBenjamin LaHaise struct ipv6_pinfo *np = inet6_sk(sk); 1059d2cf3361SBenjamin LaHaise struct udphdr *uh = udp_hdr(skb); 1060d2cf3361SBenjamin LaHaise 1061d2cf3361SBenjamin LaHaise if (!skb_dst(skb) || !skb_dst(skb)->dev || 1062d2cf3361SBenjamin LaHaise !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) { 1063d2cf3361SBenjamin LaHaise __wsum csum = skb_checksum(skb, 0, udp_len, 0); 1064d2cf3361SBenjamin LaHaise skb->ip_summed = CHECKSUM_UNNECESSARY; 1065d2cf3361SBenjamin LaHaise uh->check = csum_ipv6_magic(&np->saddr, &np->daddr, udp_len, 1066d2cf3361SBenjamin LaHaise IPPROTO_UDP, csum); 1067d2cf3361SBenjamin LaHaise if (uh->check == 0) 1068d2cf3361SBenjamin LaHaise uh->check = CSUM_MANGLED_0; 1069d2cf3361SBenjamin LaHaise } else { 1070d2cf3361SBenjamin LaHaise skb->ip_summed = CHECKSUM_PARTIAL; 1071d2cf3361SBenjamin LaHaise skb->csum_start = skb_transport_header(skb) - skb->head; 1072d2cf3361SBenjamin LaHaise skb->csum_offset = offsetof(struct udphdr, check); 1073d2cf3361SBenjamin LaHaise uh->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, 1074d2cf3361SBenjamin LaHaise udp_len, IPPROTO_UDP, 0); 1075d2cf3361SBenjamin LaHaise } 1076d2cf3361SBenjamin LaHaise } 1077d2cf3361SBenjamin LaHaise #endif 1078d2cf3361SBenjamin LaHaise 1079fd558d18SJames Chapman /* If caller requires the skb to have a ppp header, the header must be 1080fd558d18SJames Chapman * inserted in the skb data before calling this function. 1081fd558d18SJames Chapman */ 1082fd558d18SJames Chapman int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) 1083fd558d18SJames Chapman { 1084fd558d18SJames Chapman int data_len = skb->len; 10850d76751fSJames Chapman struct l2tp_tunnel *tunnel = session->tunnel; 10860d76751fSJames Chapman struct sock *sk = tunnel->sock; 1087d9d8da80SDavid S. Miller struct flowi *fl; 1088fd558d18SJames Chapman struct udphdr *uh; 1089fd558d18SJames Chapman struct inet_sock *inet; 1090fd558d18SJames Chapman __wsum csum; 1091fd558d18SJames Chapman int old_headroom; 1092fd558d18SJames Chapman int new_headroom; 1093fd558d18SJames Chapman int headroom; 10940d76751fSJames Chapman int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; 10950d76751fSJames Chapman int udp_len; 1096fd558d18SJames Chapman 1097fd558d18SJames Chapman /* Check that there's enough headroom in the skb to insert IP, 1098fd558d18SJames Chapman * UDP and L2TP headers. If not enough, expand it to 1099fd558d18SJames Chapman * make room. Adjust truesize. 1100fd558d18SJames Chapman */ 1101fd558d18SJames Chapman headroom = NET_SKB_PAD + sizeof(struct iphdr) + 11020d76751fSJames Chapman uhlen + hdr_len; 1103fd558d18SJames Chapman old_headroom = skb_headroom(skb); 1104835acf5dSEric Dumazet if (skb_cow_head(skb, headroom)) { 1105835acf5dSEric Dumazet dev_kfree_skb(skb); 1106fd558d18SJames Chapman goto abort; 1107835acf5dSEric Dumazet } 1108fd558d18SJames Chapman 1109fd558d18SJames Chapman new_headroom = skb_headroom(skb); 1110fd558d18SJames Chapman skb_orphan(skb); 1111fd558d18SJames Chapman skb->truesize += new_headroom - old_headroom; 1112fd558d18SJames Chapman 1113fd558d18SJames Chapman /* Setup L2TP header */ 1114f7faffa3SJames Chapman session->build_header(session, __skb_push(skb, hdr_len)); 1115fd558d18SJames Chapman 11160d76751fSJames Chapman /* Reset skb netfilter state */ 1117fd558d18SJames Chapman memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 1118fd558d18SJames Chapman IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 1119fd558d18SJames Chapman IPSKB_REROUTED); 1120fd558d18SJames Chapman nf_reset(skb); 1121fd558d18SJames Chapman 11226af88da1SDavid S. Miller bh_lock_sock(sk); 11236af88da1SDavid S. Miller if (sock_owned_by_user(sk)) { 11246af88da1SDavid S. Miller dev_kfree_skb(skb); 11256af88da1SDavid S. Miller goto out_unlock; 11266af88da1SDavid S. Miller } 11276af88da1SDavid S. Miller 1128fd558d18SJames Chapman /* Get routing info from the tunnel socket */ 1129fd558d18SJames Chapman skb_dst_drop(skb); 113071b1391aSFlorian Westphal skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); 11310d76751fSJames Chapman 1132d9d8da80SDavid S. Miller inet = inet_sk(sk); 1133d9d8da80SDavid S. Miller fl = &inet->cork.fl; 11340d76751fSJames Chapman switch (tunnel->encap) { 11350d76751fSJames Chapman case L2TP_ENCAPTYPE_UDP: 11360d76751fSJames Chapman /* Setup UDP header */ 11370d76751fSJames Chapman __skb_push(skb, sizeof(*uh)); 11380d76751fSJames Chapman skb_reset_transport_header(skb); 11390d76751fSJames Chapman uh = udp_hdr(skb); 11400d76751fSJames Chapman uh->source = inet->inet_sport; 11410d76751fSJames Chapman uh->dest = inet->inet_dport; 11420d76751fSJames Chapman udp_len = uhlen + hdr_len + data_len; 11430d76751fSJames Chapman uh->len = htons(udp_len); 11440d76751fSJames Chapman uh->check = 0; 1145fd558d18SJames Chapman 1146fd558d18SJames Chapman /* Calculate UDP checksum if configured to do so */ 1147d2cf3361SBenjamin LaHaise #if IS_ENABLED(CONFIG_IPV6) 1148d2cf3361SBenjamin LaHaise if (sk->sk_family == PF_INET6) 1149d2cf3361SBenjamin LaHaise l2tp_xmit_ipv6_csum(sk, skb, udp_len); 1150d2cf3361SBenjamin LaHaise else 1151d2cf3361SBenjamin LaHaise #endif 1152fd558d18SJames Chapman if (sk->sk_no_check == UDP_CSUM_NOXMIT) 1153fd558d18SJames Chapman skb->ip_summed = CHECKSUM_NONE; 1154fd558d18SJames Chapman else if ((skb_dst(skb) && skb_dst(skb)->dev) && 1155fd558d18SJames Chapman (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) { 1156fd558d18SJames Chapman skb->ip_summed = CHECKSUM_COMPLETE; 1157fd558d18SJames Chapman csum = skb_checksum(skb, 0, udp_len, 0); 1158fd558d18SJames Chapman uh->check = csum_tcpudp_magic(inet->inet_saddr, 1159fd558d18SJames Chapman inet->inet_daddr, 1160fd558d18SJames Chapman udp_len, IPPROTO_UDP, csum); 1161fd558d18SJames Chapman if (uh->check == 0) 1162fd558d18SJames Chapman uh->check = CSUM_MANGLED_0; 1163fd558d18SJames Chapman } else { 1164fd558d18SJames Chapman skb->ip_summed = CHECKSUM_PARTIAL; 1165fd558d18SJames Chapman skb->csum_start = skb_transport_header(skb) - skb->head; 1166fd558d18SJames Chapman skb->csum_offset = offsetof(struct udphdr, check); 1167fd558d18SJames Chapman uh->check = ~csum_tcpudp_magic(inet->inet_saddr, 1168fd558d18SJames Chapman inet->inet_daddr, 1169fd558d18SJames Chapman udp_len, IPPROTO_UDP, 0); 1170fd558d18SJames Chapman } 11710d76751fSJames Chapman break; 11720d76751fSJames Chapman 11730d76751fSJames Chapman case L2TP_ENCAPTYPE_IP: 11740d76751fSJames Chapman break; 11750d76751fSJames Chapman } 11760d76751fSJames Chapman 11770d76751fSJames Chapman l2tp_skb_set_owner_w(skb, sk); 1178fd558d18SJames Chapman 1179d9d8da80SDavid S. Miller l2tp_xmit_core(session, skb, fl, data_len); 11806af88da1SDavid S. Miller out_unlock: 11816af88da1SDavid S. Miller bh_unlock_sock(sk); 1182fd558d18SJames Chapman 1183fd558d18SJames Chapman abort: 1184fd558d18SJames Chapman return 0; 1185fd558d18SJames Chapman } 1186fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_xmit_skb); 1187fd558d18SJames Chapman 1188fd558d18SJames Chapman /***************************************************************************** 1189fd558d18SJames Chapman * Tinnel and session create/destroy. 1190fd558d18SJames Chapman *****************************************************************************/ 1191fd558d18SJames Chapman 1192fd558d18SJames Chapman /* Tunnel socket destruct hook. 1193fd558d18SJames Chapman * The tunnel context is deleted only when all session sockets have been 1194fd558d18SJames Chapman * closed. 1195fd558d18SJames Chapman */ 1196fc130840Sstephen hemminger static void l2tp_tunnel_destruct(struct sock *sk) 1197fd558d18SJames Chapman { 1198fd558d18SJames Chapman struct l2tp_tunnel *tunnel; 1199fd558d18SJames Chapman 1200fd558d18SJames Chapman tunnel = sk->sk_user_data; 1201fd558d18SJames Chapman if (tunnel == NULL) 1202fd558d18SJames Chapman goto end; 1203fd558d18SJames Chapman 1204fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1205fd558d18SJames Chapman "%s: closing...\n", tunnel->name); 1206fd558d18SJames Chapman 1207fd558d18SJames Chapman /* Close all sessions */ 1208fd558d18SJames Chapman l2tp_tunnel_closeall(tunnel); 1209fd558d18SJames Chapman 12100d76751fSJames Chapman switch (tunnel->encap) { 12110d76751fSJames Chapman case L2TP_ENCAPTYPE_UDP: 1212fd558d18SJames Chapman /* No longer an encapsulation socket. See net/ipv4/udp.c */ 1213fd558d18SJames Chapman (udp_sk(sk))->encap_type = 0; 1214fd558d18SJames Chapman (udp_sk(sk))->encap_rcv = NULL; 12150d76751fSJames Chapman break; 12160d76751fSJames Chapman case L2TP_ENCAPTYPE_IP: 12170d76751fSJames Chapman break; 12180d76751fSJames Chapman } 1219fd558d18SJames Chapman 1220fd558d18SJames Chapman /* Remove hooks into tunnel socket */ 1221fd558d18SJames Chapman tunnel->sock = NULL; 1222fd558d18SJames Chapman sk->sk_destruct = tunnel->old_sk_destruct; 1223fd558d18SJames Chapman sk->sk_user_data = NULL; 1224fd558d18SJames Chapman 1225fd558d18SJames Chapman /* Call the original destructor */ 1226fd558d18SJames Chapman if (sk->sk_destruct) 1227fd558d18SJames Chapman (*sk->sk_destruct)(sk); 1228fd558d18SJames Chapman 1229fd558d18SJames Chapman /* We're finished with the socket */ 1230fd558d18SJames Chapman l2tp_tunnel_dec_refcount(tunnel); 1231fd558d18SJames Chapman 1232fd558d18SJames Chapman end: 1233fd558d18SJames Chapman return; 1234fd558d18SJames Chapman } 1235fd558d18SJames Chapman 1236fd558d18SJames Chapman /* When the tunnel is closed, all the attached sessions need to go too. 1237fd558d18SJames Chapman */ 1238fc130840Sstephen hemminger static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) 1239fd558d18SJames Chapman { 1240fd558d18SJames Chapman int hash; 1241fd558d18SJames Chapman struct hlist_node *walk; 1242fd558d18SJames Chapman struct hlist_node *tmp; 1243fd558d18SJames Chapman struct l2tp_session *session; 1244fd558d18SJames Chapman 1245fd558d18SJames Chapman BUG_ON(tunnel == NULL); 1246fd558d18SJames Chapman 1247fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1248fd558d18SJames Chapman "%s: closing all sessions...\n", tunnel->name); 1249fd558d18SJames Chapman 1250fd558d18SJames Chapman write_lock_bh(&tunnel->hlist_lock); 1251fd558d18SJames Chapman for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { 1252fd558d18SJames Chapman again: 1253fd558d18SJames Chapman hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { 1254fd558d18SJames Chapman session = hlist_entry(walk, struct l2tp_session, hlist); 1255fd558d18SJames Chapman 1256fd558d18SJames Chapman PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO, 1257fd558d18SJames Chapman "%s: closing session\n", session->name); 1258fd558d18SJames Chapman 1259fd558d18SJames Chapman hlist_del_init(&session->hlist); 1260fd558d18SJames Chapman 1261fd558d18SJames Chapman /* Since we should hold the sock lock while 1262fd558d18SJames Chapman * doing any unbinding, we need to release the 1263fd558d18SJames Chapman * lock we're holding before taking that lock. 1264fd558d18SJames Chapman * Hold a reference to the sock so it doesn't 1265fd558d18SJames Chapman * disappear as we're jumping between locks. 1266fd558d18SJames Chapman */ 1267fd558d18SJames Chapman if (session->ref != NULL) 1268fd558d18SJames Chapman (*session->ref)(session); 1269fd558d18SJames Chapman 1270fd558d18SJames Chapman write_unlock_bh(&tunnel->hlist_lock); 1271fd558d18SJames Chapman 1272f7faffa3SJames Chapman if (tunnel->version != L2TP_HDR_VER_2) { 1273f7faffa3SJames Chapman struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1274f7faffa3SJames Chapman 1275e02d494dSJames Chapman spin_lock_bh(&pn->l2tp_session_hlist_lock); 1276e02d494dSJames Chapman hlist_del_init_rcu(&session->global_hlist); 1277e02d494dSJames Chapman spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1278e02d494dSJames Chapman synchronize_rcu(); 1279f7faffa3SJames Chapman } 1280f7faffa3SJames Chapman 1281fd558d18SJames Chapman if (session->session_close != NULL) 1282fd558d18SJames Chapman (*session->session_close)(session); 1283fd558d18SJames Chapman 1284fd558d18SJames Chapman if (session->deref != NULL) 1285fd558d18SJames Chapman (*session->deref)(session); 1286fd558d18SJames Chapman 1287fd558d18SJames Chapman write_lock_bh(&tunnel->hlist_lock); 1288fd558d18SJames Chapman 1289fd558d18SJames Chapman /* Now restart from the beginning of this hash 1290fd558d18SJames Chapman * chain. We always remove a session from the 1291fd558d18SJames Chapman * list so we are guaranteed to make forward 1292fd558d18SJames Chapman * progress. 1293fd558d18SJames Chapman */ 1294fd558d18SJames Chapman goto again; 1295fd558d18SJames Chapman } 1296fd558d18SJames Chapman } 1297fd558d18SJames Chapman write_unlock_bh(&tunnel->hlist_lock); 1298fd558d18SJames Chapman } 1299fd558d18SJames Chapman 1300fd558d18SJames Chapman /* Really kill the tunnel. 1301fd558d18SJames Chapman * Come here only when all sessions have been cleared from the tunnel. 1302fd558d18SJames Chapman */ 1303fc130840Sstephen hemminger static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) 1304fd558d18SJames Chapman { 1305fd558d18SJames Chapman struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1306fd558d18SJames Chapman 1307fd558d18SJames Chapman BUG_ON(atomic_read(&tunnel->ref_count) != 0); 1308fd558d18SJames Chapman BUG_ON(tunnel->sock != NULL); 1309fd558d18SJames Chapman 1310fd558d18SJames Chapman PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, 1311fd558d18SJames Chapman "%s: free...\n", tunnel->name); 1312fd558d18SJames Chapman 1313fd558d18SJames Chapman /* Remove from tunnel list */ 1314e02d494dSJames Chapman spin_lock_bh(&pn->l2tp_tunnel_list_lock); 1315e02d494dSJames Chapman list_del_rcu(&tunnel->list); 1316e02d494dSJames Chapman spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1317e02d494dSJames Chapman synchronize_rcu(); 1318fd558d18SJames Chapman 1319fd558d18SJames Chapman atomic_dec(&l2tp_tunnel_count); 1320fd558d18SJames Chapman kfree(tunnel); 1321fd558d18SJames Chapman } 1322fd558d18SJames Chapman 1323789a4a2cSJames Chapman /* Create a socket for the tunnel, if one isn't set up by 1324789a4a2cSJames Chapman * userspace. This is used for static tunnels where there is no 1325789a4a2cSJames Chapman * managing L2TP daemon. 1326789a4a2cSJames Chapman */ 1327789a4a2cSJames Chapman static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) 1328789a4a2cSJames Chapman { 1329789a4a2cSJames Chapman int err = -EINVAL; 1330789a4a2cSJames Chapman struct sockaddr_in udp_addr; 1331789a4a2cSJames Chapman struct sockaddr_l2tpip ip_addr; 13327bddd0dbSEric Dumazet struct socket *sock = NULL; 1333789a4a2cSJames Chapman 1334789a4a2cSJames Chapman switch (cfg->encap) { 1335789a4a2cSJames Chapman case L2TP_ENCAPTYPE_UDP: 1336789a4a2cSJames Chapman err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp); 1337789a4a2cSJames Chapman if (err < 0) 1338789a4a2cSJames Chapman goto out; 1339789a4a2cSJames Chapman 1340789a4a2cSJames Chapman sock = *sockp; 1341789a4a2cSJames Chapman 1342789a4a2cSJames Chapman memset(&udp_addr, 0, sizeof(udp_addr)); 1343789a4a2cSJames Chapman udp_addr.sin_family = AF_INET; 1344789a4a2cSJames Chapman udp_addr.sin_addr = cfg->local_ip; 1345789a4a2cSJames Chapman udp_addr.sin_port = htons(cfg->local_udp_port); 1346789a4a2cSJames Chapman err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr)); 1347789a4a2cSJames Chapman if (err < 0) 1348789a4a2cSJames Chapman goto out; 1349789a4a2cSJames Chapman 1350789a4a2cSJames Chapman udp_addr.sin_family = AF_INET; 1351789a4a2cSJames Chapman udp_addr.sin_addr = cfg->peer_ip; 1352789a4a2cSJames Chapman udp_addr.sin_port = htons(cfg->peer_udp_port); 1353789a4a2cSJames Chapman err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0); 1354789a4a2cSJames Chapman if (err < 0) 1355789a4a2cSJames Chapman goto out; 1356789a4a2cSJames Chapman 1357789a4a2cSJames Chapman if (!cfg->use_udp_checksums) 1358789a4a2cSJames Chapman sock->sk->sk_no_check = UDP_CSUM_NOXMIT; 1359789a4a2cSJames Chapman 1360789a4a2cSJames Chapman break; 1361789a4a2cSJames Chapman 1362789a4a2cSJames Chapman case L2TP_ENCAPTYPE_IP: 1363789a4a2cSJames Chapman err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp); 1364789a4a2cSJames Chapman if (err < 0) 1365789a4a2cSJames Chapman goto out; 1366789a4a2cSJames Chapman 1367789a4a2cSJames Chapman sock = *sockp; 1368789a4a2cSJames Chapman 1369789a4a2cSJames Chapman memset(&ip_addr, 0, sizeof(ip_addr)); 1370789a4a2cSJames Chapman ip_addr.l2tp_family = AF_INET; 1371789a4a2cSJames Chapman ip_addr.l2tp_addr = cfg->local_ip; 1372789a4a2cSJames Chapman ip_addr.l2tp_conn_id = tunnel_id; 1373789a4a2cSJames Chapman err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr)); 1374789a4a2cSJames Chapman if (err < 0) 1375789a4a2cSJames Chapman goto out; 1376789a4a2cSJames Chapman 1377789a4a2cSJames Chapman ip_addr.l2tp_family = AF_INET; 1378789a4a2cSJames Chapman ip_addr.l2tp_addr = cfg->peer_ip; 1379789a4a2cSJames Chapman ip_addr.l2tp_conn_id = peer_tunnel_id; 1380789a4a2cSJames Chapman err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0); 1381789a4a2cSJames Chapman if (err < 0) 1382789a4a2cSJames Chapman goto out; 1383789a4a2cSJames Chapman 1384789a4a2cSJames Chapman break; 1385789a4a2cSJames Chapman 1386789a4a2cSJames Chapman default: 1387789a4a2cSJames Chapman goto out; 1388789a4a2cSJames Chapman } 1389789a4a2cSJames Chapman 1390789a4a2cSJames Chapman out: 1391789a4a2cSJames Chapman if ((err < 0) && sock) { 1392789a4a2cSJames Chapman sock_release(sock); 1393789a4a2cSJames Chapman *sockp = NULL; 1394789a4a2cSJames Chapman } 1395789a4a2cSJames Chapman 1396789a4a2cSJames Chapman return err; 1397789a4a2cSJames Chapman } 1398789a4a2cSJames Chapman 1399fd558d18SJames Chapman 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) 1400fd558d18SJames Chapman { 1401fd558d18SJames Chapman struct l2tp_tunnel *tunnel = NULL; 1402fd558d18SJames Chapman int err; 1403fd558d18SJames Chapman struct socket *sock = NULL; 1404fd558d18SJames Chapman struct sock *sk = NULL; 1405fd558d18SJames Chapman struct l2tp_net *pn; 14060d76751fSJames Chapman enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; 1407fd558d18SJames Chapman 1408fd558d18SJames Chapman /* Get the tunnel socket from the fd, which was opened by 1409789a4a2cSJames Chapman * the userspace L2TP daemon. If not specified, create a 1410789a4a2cSJames Chapman * kernel socket. 1411fd558d18SJames Chapman */ 1412789a4a2cSJames Chapman if (fd < 0) { 1413789a4a2cSJames Chapman err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock); 1414789a4a2cSJames Chapman if (err < 0) 1415789a4a2cSJames Chapman goto err; 1416789a4a2cSJames Chapman } else { 1417fd558d18SJames Chapman err = -EBADF; 1418fd558d18SJames Chapman sock = sockfd_lookup(fd, &err); 1419fd558d18SJames Chapman if (!sock) { 1420fd558d18SJames Chapman printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", 1421fd558d18SJames Chapman tunnel_id, fd, err); 1422fd558d18SJames Chapman goto err; 1423fd558d18SJames Chapman } 1424789a4a2cSJames Chapman } 1425fd558d18SJames Chapman 1426fd558d18SJames Chapman sk = sock->sk; 1427fd558d18SJames Chapman 14280d76751fSJames Chapman if (cfg != NULL) 14290d76751fSJames Chapman encap = cfg->encap; 14300d76751fSJames Chapman 1431fd558d18SJames Chapman /* Quick sanity checks */ 14320d76751fSJames Chapman switch (encap) { 14330d76751fSJames Chapman case L2TP_ENCAPTYPE_UDP: 1434fd558d18SJames Chapman err = -EPROTONOSUPPORT; 1435fd558d18SJames Chapman if (sk->sk_protocol != IPPROTO_UDP) { 1436fd558d18SJames Chapman printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 1437fd558d18SJames Chapman tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); 1438fd558d18SJames Chapman goto err; 1439fd558d18SJames Chapman } 14400d76751fSJames Chapman break; 14410d76751fSJames Chapman case L2TP_ENCAPTYPE_IP: 14420d76751fSJames Chapman err = -EPROTONOSUPPORT; 14430d76751fSJames Chapman if (sk->sk_protocol != IPPROTO_L2TP) { 14440d76751fSJames Chapman printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", 14450d76751fSJames Chapman tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); 1446fd558d18SJames Chapman goto err; 1447fd558d18SJames Chapman } 14480d76751fSJames Chapman break; 14490d76751fSJames Chapman } 1450fd558d18SJames Chapman 1451fd558d18SJames Chapman /* Check if this socket has already been prepped */ 1452fd558d18SJames Chapman tunnel = (struct l2tp_tunnel *)sk->sk_user_data; 1453fd558d18SJames Chapman if (tunnel != NULL) { 1454fd558d18SJames Chapman /* This socket has already been prepped */ 1455fd558d18SJames Chapman err = -EBUSY; 1456fd558d18SJames Chapman goto err; 1457fd558d18SJames Chapman } 1458fd558d18SJames Chapman 1459fd558d18SJames Chapman tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); 1460fd558d18SJames Chapman if (tunnel == NULL) { 1461fd558d18SJames Chapman err = -ENOMEM; 1462fd558d18SJames Chapman goto err; 1463fd558d18SJames Chapman } 1464fd558d18SJames Chapman 1465fd558d18SJames Chapman tunnel->version = version; 1466fd558d18SJames Chapman tunnel->tunnel_id = tunnel_id; 1467fd558d18SJames Chapman tunnel->peer_tunnel_id = peer_tunnel_id; 1468fd558d18SJames Chapman tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; 1469fd558d18SJames Chapman 1470fd558d18SJames Chapman tunnel->magic = L2TP_TUNNEL_MAGIC; 1471fd558d18SJames Chapman sprintf(&tunnel->name[0], "tunl %u", tunnel_id); 1472fd558d18SJames Chapman rwlock_init(&tunnel->hlist_lock); 1473fd558d18SJames Chapman 1474fd558d18SJames Chapman /* The net we belong to */ 1475fd558d18SJames Chapman tunnel->l2tp_net = net; 1476fd558d18SJames Chapman pn = l2tp_pernet(net); 1477fd558d18SJames Chapman 14780d76751fSJames Chapman if (cfg != NULL) 1479fd558d18SJames Chapman tunnel->debug = cfg->debug; 1480fd558d18SJames Chapman 1481fd558d18SJames Chapman /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 14820d76751fSJames Chapman tunnel->encap = encap; 14830d76751fSJames Chapman if (encap == L2TP_ENCAPTYPE_UDP) { 14840d76751fSJames Chapman /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ 1485fd558d18SJames Chapman udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; 1486fd558d18SJames Chapman udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; 1487d2cf3361SBenjamin LaHaise #if IS_ENABLED(CONFIG_IPV6) 1488d2cf3361SBenjamin LaHaise if (sk->sk_family == PF_INET6) 1489d2cf3361SBenjamin LaHaise udpv6_encap_enable(); 1490d2cf3361SBenjamin LaHaise else 1491d2cf3361SBenjamin LaHaise #endif 1492447167bfSEric Dumazet udp_encap_enable(); 14930d76751fSJames Chapman } 1494fd558d18SJames Chapman 1495fd558d18SJames Chapman sk->sk_user_data = tunnel; 1496fd558d18SJames Chapman 1497fd558d18SJames Chapman /* Hook on the tunnel socket destructor so that we can cleanup 1498fd558d18SJames Chapman * if the tunnel socket goes away. 1499fd558d18SJames Chapman */ 1500fd558d18SJames Chapman tunnel->old_sk_destruct = sk->sk_destruct; 1501fd558d18SJames Chapman sk->sk_destruct = &l2tp_tunnel_destruct; 1502fd558d18SJames Chapman tunnel->sock = sk; 1503fd558d18SJames Chapman sk->sk_allocation = GFP_ATOMIC; 1504fd558d18SJames Chapman 1505fd558d18SJames Chapman /* Add tunnel to our list */ 1506fd558d18SJames Chapman INIT_LIST_HEAD(&tunnel->list); 1507fd558d18SJames Chapman atomic_inc(&l2tp_tunnel_count); 1508fd558d18SJames Chapman 1509fd558d18SJames Chapman /* Bump the reference count. The tunnel context is deleted 15101769192aSEric Dumazet * only when this drops to zero. Must be done before list insertion 1511fd558d18SJames Chapman */ 1512fd558d18SJames Chapman l2tp_tunnel_inc_refcount(tunnel); 15131769192aSEric Dumazet spin_lock_bh(&pn->l2tp_tunnel_list_lock); 15141769192aSEric Dumazet list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); 15151769192aSEric Dumazet spin_unlock_bh(&pn->l2tp_tunnel_list_lock); 1516fd558d18SJames Chapman 1517fd558d18SJames Chapman err = 0; 1518fd558d18SJames Chapman err: 1519fd558d18SJames Chapman if (tunnelp) 1520fd558d18SJames Chapman *tunnelp = tunnel; 1521fd558d18SJames Chapman 1522789a4a2cSJames Chapman /* If tunnel's socket was created by the kernel, it doesn't 1523789a4a2cSJames Chapman * have a file. 1524789a4a2cSJames Chapman */ 1525789a4a2cSJames Chapman if (sock && sock->file) 1526fd558d18SJames Chapman sockfd_put(sock); 1527fd558d18SJames Chapman 1528fd558d18SJames Chapman return err; 1529fd558d18SJames Chapman } 1530fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_tunnel_create); 1531fd558d18SJames Chapman 1532309795f4SJames Chapman /* This function is used by the netlink TUNNEL_DELETE command. 1533309795f4SJames Chapman */ 1534309795f4SJames Chapman int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) 1535309795f4SJames Chapman { 1536309795f4SJames Chapman int err = 0; 1537789a4a2cSJames Chapman struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL; 1538309795f4SJames Chapman 1539309795f4SJames Chapman /* Force the tunnel socket to close. This will eventually 1540309795f4SJames Chapman * cause the tunnel to be deleted via the normal socket close 1541309795f4SJames Chapman * mechanisms when userspace closes the tunnel socket. 1542309795f4SJames Chapman */ 1543789a4a2cSJames Chapman if (sock != NULL) { 1544789a4a2cSJames Chapman err = inet_shutdown(sock, 2); 1545789a4a2cSJames Chapman 1546789a4a2cSJames Chapman /* If the tunnel's socket was created by the kernel, 1547789a4a2cSJames Chapman * close the socket here since the socket was not 1548789a4a2cSJames Chapman * created by userspace. 1549789a4a2cSJames Chapman */ 1550789a4a2cSJames Chapman if (sock->file == NULL) 1551789a4a2cSJames Chapman err = inet_release(sock); 1552789a4a2cSJames Chapman } 1553309795f4SJames Chapman 1554309795f4SJames Chapman return err; 1555309795f4SJames Chapman } 1556309795f4SJames Chapman EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); 1557309795f4SJames Chapman 1558fd558d18SJames Chapman /* Really kill the session. 1559fd558d18SJames Chapman */ 1560fd558d18SJames Chapman void l2tp_session_free(struct l2tp_session *session) 1561fd558d18SJames Chapman { 1562fd558d18SJames Chapman struct l2tp_tunnel *tunnel; 1563fd558d18SJames Chapman 1564fd558d18SJames Chapman BUG_ON(atomic_read(&session->ref_count) != 0); 1565fd558d18SJames Chapman 1566fd558d18SJames Chapman tunnel = session->tunnel; 1567fd558d18SJames Chapman if (tunnel != NULL) { 1568fd558d18SJames Chapman BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); 1569fd558d18SJames Chapman 1570fd558d18SJames Chapman /* Delete the session from the hash */ 1571fd558d18SJames Chapman write_lock_bh(&tunnel->hlist_lock); 1572fd558d18SJames Chapman hlist_del_init(&session->hlist); 1573fd558d18SJames Chapman write_unlock_bh(&tunnel->hlist_lock); 1574fd558d18SJames Chapman 1575f7faffa3SJames Chapman /* Unlink from the global hash if not L2TPv2 */ 1576f7faffa3SJames Chapman if (tunnel->version != L2TP_HDR_VER_2) { 1577f7faffa3SJames Chapman struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1578f7faffa3SJames Chapman 1579e02d494dSJames Chapman spin_lock_bh(&pn->l2tp_session_hlist_lock); 1580e02d494dSJames Chapman hlist_del_init_rcu(&session->global_hlist); 1581e02d494dSJames Chapman spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1582e02d494dSJames Chapman synchronize_rcu(); 1583f7faffa3SJames Chapman } 1584f7faffa3SJames Chapman 1585fd558d18SJames Chapman if (session->session_id != 0) 1586fd558d18SJames Chapman atomic_dec(&l2tp_session_count); 1587fd558d18SJames Chapman 1588fd558d18SJames Chapman sock_put(tunnel->sock); 1589fd558d18SJames Chapman 1590fd558d18SJames Chapman /* This will delete the tunnel context if this 1591fd558d18SJames Chapman * is the last session on the tunnel. 1592fd558d18SJames Chapman */ 1593fd558d18SJames Chapman session->tunnel = NULL; 1594fd558d18SJames Chapman l2tp_tunnel_dec_refcount(tunnel); 1595fd558d18SJames Chapman } 1596fd558d18SJames Chapman 1597fd558d18SJames Chapman kfree(session); 1598fd558d18SJames Chapman 1599fd558d18SJames Chapman return; 1600fd558d18SJames Chapman } 1601fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_free); 1602fd558d18SJames Chapman 1603309795f4SJames Chapman /* This function is used by the netlink SESSION_DELETE command and by 1604309795f4SJames Chapman pseudowire modules. 1605309795f4SJames Chapman */ 1606309795f4SJames Chapman int l2tp_session_delete(struct l2tp_session *session) 1607309795f4SJames Chapman { 1608309795f4SJames Chapman if (session->session_close != NULL) 1609309795f4SJames Chapman (*session->session_close)(session); 1610309795f4SJames Chapman 1611309795f4SJames Chapman l2tp_session_dec_refcount(session); 1612309795f4SJames Chapman 1613309795f4SJames Chapman return 0; 1614309795f4SJames Chapman } 1615309795f4SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_delete); 1616309795f4SJames Chapman 1617309795f4SJames Chapman 1618f7faffa3SJames Chapman /* We come here whenever a session's send_seq, cookie_len or 1619f7faffa3SJames Chapman * l2specific_len parameters are set. 1620f7faffa3SJames Chapman */ 1621fc130840Sstephen hemminger static void l2tp_session_set_header_len(struct l2tp_session *session, int version) 1622f7faffa3SJames Chapman { 1623f7faffa3SJames Chapman if (version == L2TP_HDR_VER_2) { 1624f7faffa3SJames Chapman session->hdr_len = 6; 1625f7faffa3SJames Chapman if (session->send_seq) 1626f7faffa3SJames Chapman session->hdr_len += 4; 1627f7faffa3SJames Chapman } else { 16280d76751fSJames Chapman session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; 16290d76751fSJames Chapman if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) 16300d76751fSJames Chapman session->hdr_len += 4; 1631f7faffa3SJames Chapman } 1632f7faffa3SJames Chapman 1633f7faffa3SJames Chapman } 1634f7faffa3SJames Chapman 1635fd558d18SJames Chapman 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) 1636fd558d18SJames Chapman { 1637fd558d18SJames Chapman struct l2tp_session *session; 1638fd558d18SJames Chapman 1639fd558d18SJames Chapman session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); 1640fd558d18SJames Chapman if (session != NULL) { 1641fd558d18SJames Chapman session->magic = L2TP_SESSION_MAGIC; 1642fd558d18SJames Chapman session->tunnel = tunnel; 1643fd558d18SJames Chapman 1644fd558d18SJames Chapman session->session_id = session_id; 1645fd558d18SJames Chapman session->peer_session_id = peer_session_id; 1646f7faffa3SJames Chapman session->nr = 1; 1647fd558d18SJames Chapman 1648fd558d18SJames Chapman sprintf(&session->name[0], "sess %u/%u", 1649fd558d18SJames Chapman tunnel->tunnel_id, session->session_id); 1650fd558d18SJames Chapman 1651fd558d18SJames Chapman skb_queue_head_init(&session->reorder_q); 1652fd558d18SJames Chapman 1653fd558d18SJames Chapman INIT_HLIST_NODE(&session->hlist); 1654f7faffa3SJames Chapman INIT_HLIST_NODE(&session->global_hlist); 1655fd558d18SJames Chapman 1656fd558d18SJames Chapman /* Inherit debug options from tunnel */ 1657fd558d18SJames Chapman session->debug = tunnel->debug; 1658fd558d18SJames Chapman 1659fd558d18SJames Chapman if (cfg) { 1660f7faffa3SJames Chapman session->pwtype = cfg->pw_type; 1661fd558d18SJames Chapman session->debug = cfg->debug; 1662fd558d18SJames Chapman session->mtu = cfg->mtu; 1663fd558d18SJames Chapman session->mru = cfg->mru; 1664fd558d18SJames Chapman session->send_seq = cfg->send_seq; 1665fd558d18SJames Chapman session->recv_seq = cfg->recv_seq; 1666fd558d18SJames Chapman session->lns_mode = cfg->lns_mode; 1667f7faffa3SJames Chapman session->reorder_timeout = cfg->reorder_timeout; 1668f7faffa3SJames Chapman session->offset = cfg->offset; 1669f7faffa3SJames Chapman session->l2specific_type = cfg->l2specific_type; 1670f7faffa3SJames Chapman session->l2specific_len = cfg->l2specific_len; 1671f7faffa3SJames Chapman session->cookie_len = cfg->cookie_len; 1672f7faffa3SJames Chapman memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); 1673f7faffa3SJames Chapman session->peer_cookie_len = cfg->peer_cookie_len; 1674f7faffa3SJames Chapman memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); 1675fd558d18SJames Chapman } 1676fd558d18SJames Chapman 1677f7faffa3SJames Chapman if (tunnel->version == L2TP_HDR_VER_2) 1678f7faffa3SJames Chapman session->build_header = l2tp_build_l2tpv2_header; 1679f7faffa3SJames Chapman else 1680f7faffa3SJames Chapman session->build_header = l2tp_build_l2tpv3_header; 1681f7faffa3SJames Chapman 1682f7faffa3SJames Chapman l2tp_session_set_header_len(session, tunnel->version); 1683f7faffa3SJames Chapman 1684fd558d18SJames Chapman /* Bump the reference count. The session context is deleted 1685fd558d18SJames Chapman * only when this drops to zero. 1686fd558d18SJames Chapman */ 1687fd558d18SJames Chapman l2tp_session_inc_refcount(session); 1688fd558d18SJames Chapman l2tp_tunnel_inc_refcount(tunnel); 1689fd558d18SJames Chapman 1690fd558d18SJames Chapman /* Ensure tunnel socket isn't deleted */ 1691fd558d18SJames Chapman sock_hold(tunnel->sock); 1692fd558d18SJames Chapman 1693fd558d18SJames Chapman /* Add session to the tunnel's hash list */ 1694fd558d18SJames Chapman write_lock_bh(&tunnel->hlist_lock); 1695fd558d18SJames Chapman hlist_add_head(&session->hlist, 1696fd558d18SJames Chapman l2tp_session_id_hash(tunnel, session_id)); 1697fd558d18SJames Chapman write_unlock_bh(&tunnel->hlist_lock); 1698fd558d18SJames Chapman 1699f7faffa3SJames Chapman /* And to the global session list if L2TPv3 */ 1700f7faffa3SJames Chapman if (tunnel->version != L2TP_HDR_VER_2) { 1701f7faffa3SJames Chapman struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); 1702f7faffa3SJames Chapman 1703e02d494dSJames Chapman spin_lock_bh(&pn->l2tp_session_hlist_lock); 1704e02d494dSJames Chapman hlist_add_head_rcu(&session->global_hlist, 1705f7faffa3SJames Chapman l2tp_session_id_hash_2(pn, session_id)); 1706e02d494dSJames Chapman spin_unlock_bh(&pn->l2tp_session_hlist_lock); 1707f7faffa3SJames Chapman } 1708f7faffa3SJames Chapman 1709fd558d18SJames Chapman /* Ignore management session in session count value */ 1710fd558d18SJames Chapman if (session->session_id != 0) 1711fd558d18SJames Chapman atomic_inc(&l2tp_session_count); 1712fd558d18SJames Chapman } 1713fd558d18SJames Chapman 1714fd558d18SJames Chapman return session; 1715fd558d18SJames Chapman } 1716fd558d18SJames Chapman EXPORT_SYMBOL_GPL(l2tp_session_create); 1717fd558d18SJames Chapman 1718fd558d18SJames Chapman /***************************************************************************** 1719fd558d18SJames Chapman * Init and cleanup 1720fd558d18SJames Chapman *****************************************************************************/ 1721fd558d18SJames Chapman 1722fd558d18SJames Chapman static __net_init int l2tp_init_net(struct net *net) 1723fd558d18SJames Chapman { 1724e773aaffSJiri Pirko struct l2tp_net *pn = net_generic(net, l2tp_net_id); 1725f7faffa3SJames Chapman int hash; 1726fd558d18SJames Chapman 1727fd558d18SJames Chapman INIT_LIST_HEAD(&pn->l2tp_tunnel_list); 1728e02d494dSJames Chapman spin_lock_init(&pn->l2tp_tunnel_list_lock); 1729fd558d18SJames Chapman 1730f7faffa3SJames Chapman for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) 1731f7faffa3SJames Chapman INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); 1732f7faffa3SJames Chapman 1733e02d494dSJames Chapman spin_lock_init(&pn->l2tp_session_hlist_lock); 1734f7faffa3SJames Chapman 1735fd558d18SJames Chapman return 0; 1736fd558d18SJames Chapman } 1737fd558d18SJames Chapman 1738fd558d18SJames Chapman static struct pernet_operations l2tp_net_ops = { 1739fd558d18SJames Chapman .init = l2tp_init_net, 1740fd558d18SJames Chapman .id = &l2tp_net_id, 1741fd558d18SJames Chapman .size = sizeof(struct l2tp_net), 1742fd558d18SJames Chapman }; 1743fd558d18SJames Chapman 1744fd558d18SJames Chapman static int __init l2tp_init(void) 1745fd558d18SJames Chapman { 1746fd558d18SJames Chapman int rc = 0; 1747fd558d18SJames Chapman 1748fd558d18SJames Chapman rc = register_pernet_device(&l2tp_net_ops); 1749fd558d18SJames Chapman if (rc) 1750fd558d18SJames Chapman goto out; 1751fd558d18SJames Chapman 1752fd558d18SJames Chapman printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); 1753fd558d18SJames Chapman 1754fd558d18SJames Chapman out: 1755fd558d18SJames Chapman return rc; 1756fd558d18SJames Chapman } 1757fd558d18SJames Chapman 1758fd558d18SJames Chapman static void __exit l2tp_exit(void) 1759fd558d18SJames Chapman { 1760fd558d18SJames Chapman unregister_pernet_device(&l2tp_net_ops); 1761fd558d18SJames Chapman } 1762fd558d18SJames Chapman 1763fd558d18SJames Chapman module_init(l2tp_init); 1764fd558d18SJames Chapman module_exit(l2tp_exit); 1765fd558d18SJames Chapman 1766fd558d18SJames Chapman MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 1767fd558d18SJames Chapman MODULE_DESCRIPTION("L2TP core"); 1768fd558d18SJames Chapman MODULE_LICENSE("GPL"); 1769fd558d18SJames Chapman MODULE_VERSION(L2TP_DRV_VERSION); 1770fd558d18SJames Chapman 1771