| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| James Chapman | 5139 | 67.49% | 32 | 21.62% |
| Tom Parkin | 963 | 12.65% | 34 | 22.97% |
| Guillaume Nault | 564 | 7.41% | 20 | 13.51% |
| Américo Wang | 229 | 3.01% | 3 | 2.03% |
| Eric Dumazet | 101 | 1.33% | 13 | 8.78% |
| Tom Herbert | 84 | 1.10% | 3 | 2.03% |
| Chris Elston | 84 | 1.10% | 1 | 0.68% |
| David S. Miller | 63 | 0.83% | 5 | 3.38% |
| Paolo Abeni | 54 | 0.71% | 1 | 0.68% |
| Benjamin LaHaise | 53 | 0.70% | 1 | 0.68% |
| Jakub Sitnicki | 35 | 0.46% | 2 | 1.35% |
| Cyrill V. Gorcunov | 26 | 0.34% | 1 | 0.68% |
| Jacob Wen | 26 | 0.34% | 2 | 1.35% |
| Martin KaFai Lau | 24 | 0.32% | 1 | 0.68% |
| Sabrina Dubroca | 23 | 0.30% | 2 | 1.35% |
| Eric W. Biedermann | 20 | 0.26% | 4 | 2.70% |
| Matthias Schiffer | 19 | 0.25% | 1 | 0.68% |
| Andy Zhou | 17 | 0.22% | 1 | 0.68% |
| Elena Reshetova | 13 | 0.17% | 1 | 0.68% |
| Lorenzo Bianconi | 11 | 0.14% | 1 | 0.68% |
| Joe Perches | 10 | 0.13% | 1 | 0.68% |
| Vasily Averin | 8 | 0.11% | 1 | 0.68% |
| Herbert Xu | 8 | 0.11% | 1 | 0.68% |
| Samuel Thibault | 6 | 0.08% | 2 | 1.35% |
| Ridge Kennedy | 5 | 0.07% | 1 | 0.68% |
| Xin Long | 5 | 0.07% | 1 | 0.68% |
| Shan Wei | 5 | 0.07% | 1 | 0.68% |
| Yue haibing | 4 | 0.05% | 1 | 0.68% |
| Stephen Hemminger | 2 | 0.03% | 1 | 0.68% |
| Alexander Couzens | 2 | 0.03% | 1 | 0.68% |
| Jiri Pirko | 2 | 0.03% | 1 | 0.68% |
| Wang Shanker | 2 | 0.03% | 1 | 0.68% |
| Xiyu Yang | 2 | 0.03% | 1 | 0.68% |
| Florian Westphal | 1 | 0.01% | 1 | 0.68% |
| Denis V. Lunev | 1 | 0.01% | 1 | 0.68% |
| Arun Sharma | 1 | 0.01% | 1 | 0.68% |
| Bhaskar Chowdhury | 1 | 0.01% | 1 | 0.68% |
| Thomas Gleixner | 1 | 0.01% | 1 | 0.68% |
| Total | 7614 | 148 |
// SPDX-License-Identifier: GPL-2.0-only /* L2TP core. * * Copyright (c) 2008,2009,2010 Katalix Systems Ltd * * This file contains some code of the original L2TPv2 pppol2tp * driver, which has the following copyright: * * Authors: Martijn van Oosterhout <kleptog@svana.org> * James Chapman (jchapman@katalix.com) * Contributors: * Michal Ostrowski <mostrows@speakeasy.net> * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> * David S. Miller (davem@redhat.com) */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/string.h> #include <linux/list.h> #include <linux/rculist.h> #include <linux/uaccess.h> #include <linux/kernel.h> #include <linux/spinlock.h> #include <linux/kthread.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/jiffies.h> #include <linux/netdevice.h> #include <linux/net.h> #include <linux/inetdevice.h> #include <linux/skbuff.h> #include <linux/init.h> #include <linux/in.h> #include <linux/ip.h> #include <linux/udp.h> #include <linux/l2tp.h> #include <linux/sort.h> #include <linux/file.h> #include <linux/nsproxy.h> #include <net/net_namespace.h> #include <net/netns/generic.h> #include <net/dst.h> #include <net/ip.h> #include <net/udp.h> #include <net/udp_tunnel.h> #include <net/inet_common.h> #include <net/xfrm.h> #include <net/protocol.h> #include <net/inet6_connection_sock.h> #include <net/inet_ecn.h> #include <net/ip6_route.h> #include <net/ip6_checksum.h> #include <asm/byteorder.h> #include <linux/atomic.h> #include "l2tp_core.h" #define CREATE_TRACE_POINTS #include "trace.h" #define L2TP_DRV_VERSION "V2.0" /* L2TP header constants */ #define L2TP_HDRFLAG_T 0x8000 #define L2TP_HDRFLAG_L 0x4000 #define L2TP_HDRFLAG_S 0x0800 #define L2TP_HDRFLAG_O 0x0200 #define L2TP_HDRFLAG_P 0x0100 #define L2TP_HDR_VER_MASK 0x000F #define L2TP_HDR_VER_2 0x0002 #define L2TP_HDR_VER_3 0x0003 /* L2TPv3 default L2-specific sublayer */ #define L2TP_SLFLAG_S 0x40000000 #define L2TP_SL_SEQ_MASK 0x00ffffff #define L2TP_HDR_SIZE_MAX 14 /* Default trace flags */ #define L2TP_DEFAULT_DEBUG_FLAGS 0 #define L2TP_DEPTH_NESTING 2 #if L2TP_DEPTH_NESTING == SINGLE_DEPTH_NESTING #error "L2TP requires its own lockdep subclass" #endif /* Private data stored for received packets in the skb. */ struct l2tp_skb_cb { u32 ns; u16 has_seq; u16 length; unsigned long expires; }; #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *)&(skb)->cb[sizeof(struct inet_skb_parm)]) static struct workqueue_struct *l2tp_wq; /* per-net private data for this module */ static unsigned int l2tp_net_id; struct l2tp_net { /* Lock for write access to l2tp_tunnel_idr */ spinlock_t l2tp_tunnel_idr_lock; struct idr l2tp_tunnel_idr; /* Lock for write access to l2tp_v[23]_session_idr/htable */ spinlock_t l2tp_session_idr_lock; struct idr l2tp_v2_session_idr; struct idr l2tp_v3_session_idr; struct hlist_head l2tp_v3_session_htable[16]; }; static inline u32 l2tp_v2_session_key(u16 tunnel_id, u16 session_id) { return ((u32)tunnel_id) << 16 | session_id; } static inline unsigned long l2tp_v3_session_hashkey(struct sock *sk, u32 session_id) { return ((unsigned long)sk) + session_id; } #if IS_ENABLED(CONFIG_IPV6) static bool l2tp_sk_is_v6(struct sock *sk) { return sk->sk_family == PF_INET6 && !ipv6_addr_v4mapped(&sk->sk_v6_daddr); } #endif static inline struct l2tp_net *l2tp_pernet(const struct net *net) { return net_generic(net, l2tp_net_id); } static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) { trace_free_tunnel(tunnel); sock_put(tunnel->sock); /* the tunnel is freed in the socket destructor */ } static void l2tp_session_free(struct l2tp_session *session) { trace_free_session(session); if (session->tunnel) l2tp_tunnel_dec_refcount(session->tunnel); kfree(session); } struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk) { struct l2tp_tunnel *tunnel = sk->sk_user_data; if (tunnel) if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC)) return NULL; return tunnel; } EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel); void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) { refcount_inc(&tunnel->ref_count); } EXPORT_SYMBOL_GPL(l2tp_tunnel_inc_refcount); void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) { if (refcount_dec_and_test(&tunnel->ref_count)) l2tp_tunnel_free(tunnel); } EXPORT_SYMBOL_GPL(l2tp_tunnel_dec_refcount); void l2tp_session_inc_refcount(struct l2tp_session *session) { refcount_inc(&session->ref_count); } EXPORT_SYMBOL_GPL(l2tp_session_inc_refcount); void l2tp_session_dec_refcount(struct l2tp_session *session) { if (refcount_dec_and_test(&session->ref_count)) l2tp_session_free(session); } EXPORT_SYMBOL_GPL(l2tp_session_dec_refcount); /* Lookup a tunnel. A new reference is held on the returned tunnel. */ struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id) { const struct l2tp_net *pn = l2tp_pernet(net); struct l2tp_tunnel *tunnel; rcu_read_lock_bh(); tunnel = idr_find(&pn->l2tp_tunnel_idr, tunnel_id); if (tunnel && refcount_inc_not_zero(&tunnel->ref_count)) { rcu_read_unlock_bh(); return tunnel; } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_tunnel_get); struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth) { struct l2tp_net *pn = l2tp_pernet(net); unsigned long tunnel_id, tmp; struct l2tp_tunnel *tunnel; int count = 0; rcu_read_lock_bh(); idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { if (tunnel && ++count > nth && refcount_inc_not_zero(&tunnel->ref_count)) { rcu_read_unlock_bh(); return tunnel; } } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth); struct l2tp_session *l2tp_v3_session_get(const struct net *net, struct sock *sk, u32 session_id) { const struct l2tp_net *pn = l2tp_pernet(net); struct l2tp_session *session; rcu_read_lock_bh(); session = idr_find(&pn->l2tp_v3_session_idr, session_id); if (session && !hash_hashed(&session->hlist) && refcount_inc_not_zero(&session->ref_count)) { rcu_read_unlock_bh(); return session; } /* If we get here and session is non-NULL, the session_id * collides with one in another tunnel. If sk is non-NULL, * find the session matching sk. */ if (session && sk) { unsigned long key = l2tp_v3_session_hashkey(sk, session->session_id); hash_for_each_possible_rcu(pn->l2tp_v3_session_htable, session, hlist, key) { if (session->tunnel->sock == sk && refcount_inc_not_zero(&session->ref_count)) { rcu_read_unlock_bh(); return session; } } } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_v3_session_get); struct l2tp_session *l2tp_v2_session_get(const struct net *net, u16 tunnel_id, u16 session_id) { u32 session_key = l2tp_v2_session_key(tunnel_id, session_id); const struct l2tp_net *pn = l2tp_pernet(net); struct l2tp_session *session; rcu_read_lock_bh(); session = idr_find(&pn->l2tp_v2_session_idr, session_key); if (session && refcount_inc_not_zero(&session->ref_count)) { rcu_read_unlock_bh(); return session; } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_v2_session_get); struct l2tp_session *l2tp_session_get(const struct net *net, struct sock *sk, int pver, u32 tunnel_id, u32 session_id) { if (pver == L2TP_HDR_VER_2) return l2tp_v2_session_get(net, tunnel_id, session_id); else return l2tp_v3_session_get(net, sk, session_id); } EXPORT_SYMBOL_GPL(l2tp_session_get); struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth) { struct l2tp_session *session; int count = 0; rcu_read_lock_bh(); list_for_each_entry_rcu(session, &tunnel->session_list, list) { if (++count > nth) { l2tp_session_inc_refcount(session); rcu_read_unlock_bh(); return session; } } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_session_get_nth); /* Lookup a session by interface name. * This is very inefficient but is only used by management interfaces. */ struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, const char *ifname) { struct l2tp_net *pn = l2tp_pernet(net); unsigned long tunnel_id, tmp; struct l2tp_session *session; struct l2tp_tunnel *tunnel; rcu_read_lock_bh(); idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { if (tunnel) { list_for_each_entry_rcu(session, &tunnel->session_list, list) { if (!strcmp(session->ifname, ifname)) { l2tp_session_inc_refcount(session); rcu_read_unlock_bh(); return session; } } } } rcu_read_unlock_bh(); return NULL; } EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname); static void l2tp_session_coll_list_add(struct l2tp_session_coll_list *clist, struct l2tp_session *session) { l2tp_session_inc_refcount(session); WARN_ON_ONCE(session->coll_list); session->coll_list = clist; spin_lock(&clist->lock); list_add(&session->clist, &clist->list); spin_unlock(&clist->lock); } static int l2tp_session_collision_add(struct l2tp_net *pn, struct l2tp_session *session1, struct l2tp_session *session2) { struct l2tp_session_coll_list *clist; lockdep_assert_held(&pn->l2tp_session_idr_lock); if (!session2) return -EEXIST; /* If existing session is in IP-encap tunnel, refuse new session */ if (session2->tunnel->encap == L2TP_ENCAPTYPE_IP) return -EEXIST; clist = session2->coll_list; if (!clist) { /* First collision. Allocate list to manage the collided sessions * and add the existing session to the list. */ clist = kmalloc(sizeof(*clist), GFP_ATOMIC); if (!clist) return -ENOMEM; spin_lock_init(&clist->lock); INIT_LIST_HEAD(&clist->list); refcount_set(&clist->ref_count, 1); l2tp_session_coll_list_add(clist, session2); } /* If existing session isn't already in the session hlist, add it. */ if (!hash_hashed(&session2->hlist)) hash_add(pn->l2tp_v3_session_htable, &session2->hlist, session2->hlist_key); /* Add new session to the hlist and collision list */ hash_add(pn->l2tp_v3_session_htable, &session1->hlist, session1->hlist_key); refcount_inc(&clist->ref_count); l2tp_session_coll_list_add(clist, session1); return 0; } static void l2tp_session_collision_del(struct l2tp_net *pn, struct l2tp_session *session) { struct l2tp_session_coll_list *clist = session->coll_list; unsigned long session_key = session->session_id; struct l2tp_session *session2; lockdep_assert_held(&pn->l2tp_session_idr_lock); hash_del(&session->hlist); if (clist) { /* Remove session from its collision list. If there * are other sessions with the same ID, replace this * session's IDR entry with that session, otherwise * remove the IDR entry. If this is the last session, * the collision list data is freed. */ spin_lock(&clist->lock); list_del_init(&session->clist); session2 = list_first_entry_or_null(&clist->list, struct l2tp_session, clist); if (session2) { void *old = idr_replace(&pn->l2tp_v3_session_idr, session2, session_key); WARN_ON_ONCE(IS_ERR_VALUE(old)); } else { void *removed = idr_remove(&pn->l2tp_v3_session_idr, session_key); WARN_ON_ONCE(removed != session); } session->coll_list = NULL; spin_unlock(&clist->lock); if (refcount_dec_and_test(&clist->ref_count)) kfree(clist); l2tp_session_dec_refcount(session); } } int l2tp_session_register(struct l2tp_session *session, struct l2tp_tunnel *tunnel) { struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); struct l2tp_session *other_session = NULL; u32 session_key; int err; spin_lock_bh(&tunnel->list_lock); spin_lock_bh(&pn->l2tp_session_idr_lock); if (!tunnel->acpt_newsess) { err = -ENODEV; goto out; } if (tunnel->version == L2TP_HDR_VER_3) { session_key = session->session_id; err = idr_alloc_u32(&pn->l2tp_v3_session_idr, NULL, &session_key, session_key, GFP_ATOMIC); /* IP encap expects session IDs to be globally unique, while * UDP encap doesn't. This isn't per the RFC, which says that * sessions are identified only by the session ID, but is to * support existing userspace which depends on it. */ if (err == -ENOSPC && tunnel->encap == L2TP_ENCAPTYPE_UDP) { other_session = idr_find(&pn->l2tp_v3_session_idr, session_key); err = l2tp_session_collision_add(pn, session, other_session); } } else { session_key = l2tp_v2_session_key(tunnel->tunnel_id, session->session_id); err = idr_alloc_u32(&pn->l2tp_v2_session_idr, NULL, &session_key, session_key, GFP_ATOMIC); } if (err) { if (err == -ENOSPC) err = -EEXIST; goto out; } l2tp_tunnel_inc_refcount(tunnel); list_add(&session->list, &tunnel->session_list); if (tunnel->version == L2TP_HDR_VER_3) { if (!other_session) idr_replace(&pn->l2tp_v3_session_idr, session, session_key); } else { idr_replace(&pn->l2tp_v2_session_idr, session, session_key); } out: spin_unlock_bh(&pn->l2tp_session_idr_lock); spin_unlock_bh(&tunnel->list_lock); if (!err) trace_register_session(session); return err; } EXPORT_SYMBOL_GPL(l2tp_session_register); /***************************************************************************** * Receive data handling *****************************************************************************/ /* Queue a skb in order. We come here only if the skb has an L2TP sequence * number. */ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) { struct sk_buff *skbp; struct sk_buff *tmp; u32 ns = L2TP_SKB_CB(skb)->ns; spin_lock_bh(&session->reorder_q.lock); skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { if (L2TP_SKB_CB(skbp)->ns > ns) { __skb_queue_before(&session->reorder_q, skbp, skb); atomic_long_inc(&session->stats.rx_oos_packets); goto out; } } __skb_queue_tail(&session->reorder_q, skb); out: spin_unlock_bh(&session->reorder_q.lock); } /* Dequeue a single skb. */ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) { struct l2tp_tunnel *tunnel = session->tunnel; int length = L2TP_SKB_CB(skb)->length; /* We're about to requeue the skb, so return resources * to its current owner (a socket receive buffer). */ skb_orphan(skb); atomic_long_inc(&tunnel->stats.rx_packets); atomic_long_add(length, &tunnel->stats.rx_bytes); atomic_long_inc(&session->stats.rx_packets); atomic_long_add(length, &session->stats.rx_bytes); if (L2TP_SKB_CB(skb)->has_seq) { /* Bump our Nr */ session->nr++; session->nr &= session->nr_max; trace_session_seqnum_update(session); } /* call private receive handler */ if (session->recv_skb) (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); else kfree_skb(skb); } /* Dequeue skbs from the session's reorder_q, subject to packet order. * Skbs that have been in the queue for too long are simply discarded. */ static void l2tp_recv_dequeue(struct l2tp_session *session) { struct sk_buff *skb; struct sk_buff *tmp; /* If the pkt at the head of the queue has the nr that we * expect to send up next, dequeue it and any other * in-sequence packets behind it. */ start: spin_lock_bh(&session->reorder_q.lock); skb_queue_walk_safe(&session->reorder_q, skb, tmp) { struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb); /* If the packet has been pending on the queue for too long, discard it */ if (time_after(jiffies, cb->expires)) { atomic_long_inc(&session->stats.rx_seq_discards); atomic_long_inc(&session->stats.rx_errors); trace_session_pkt_expired(session, cb->ns); session->reorder_skip = 1; __skb_unlink(skb, &session->reorder_q); kfree_skb(skb); continue; } if (cb->has_seq) { if (session->reorder_skip) { session->reorder_skip = 0; session->nr = cb->ns; trace_session_seqnum_reset(session); } if (cb->ns != session->nr) goto out; } __skb_unlink(skb, &session->reorder_q); /* Process the skb. We release the queue lock while we * do so to let other contexts process the queue. */ spin_unlock_bh(&session->reorder_q.lock); l2tp_recv_dequeue_skb(session, skb); goto start; } out: spin_unlock_bh(&session->reorder_q.lock); } static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr) { u32 nws; if (nr >= session->nr) nws = nr - session->nr; else nws = (session->nr_max + 1) - (session->nr - nr); return nws < session->nr_window_size; } /* If packet has sequence numbers, queue it if acceptable. Returns 0 if * acceptable, else non-zero. */ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) { struct l2tp_skb_cb *cb = L2TP_SKB_CB(skb); if (!l2tp_seq_check_rx_window(session, cb->ns)) { /* Packet sequence number is outside allowed window. * Discard it. */ trace_session_pkt_outside_rx_window(session, cb->ns); goto discard; } if (session->reorder_timeout != 0) { /* Packet reordering enabled. Add skb to session's * reorder queue, in order of ns. */ l2tp_recv_queue_skb(session, skb); goto out; } /* Packet reordering disabled. Discard out-of-sequence packets, while * tracking the number if in-sequence packets after the first OOS packet * is seen. After nr_oos_count_max in-sequence packets, reset the * sequence number to re-enable packet reception. */ if (cb->ns == session->nr) { skb_queue_tail(&session->reorder_q, skb); } else { u32 nr_oos = cb->ns; u32 nr_next = (session->nr_oos + 1) & session->nr_max; if (nr_oos == nr_next) session->nr_oos_count++; else session->nr_oos_count = 0; session->nr_oos = nr_oos; if (session->nr_oos_count > session->nr_oos_count_max) { session->reorder_skip = 1; } if (!session->reorder_skip) { atomic_long_inc(&session->stats.rx_seq_discards); trace_session_pkt_oos(session, cb->ns); goto discard; } skb_queue_tail(&session->reorder_q, skb); } out: return 0; discard: return 1; } /* Do receive processing of L2TP data frames. We handle both L2TPv2 * and L2TPv3 data frames here. * * L2TPv2 Data Message Header * * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Tunnel ID | Session ID | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Ns (opt) | Nr (opt) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Offset Size (opt) | Offset pad... (opt) * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Data frames are marked by T=0. All other fields are the same as * those in L2TP control frames. * * L2TPv3 Data Message Header * * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | L2TP Session Header | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | L2-Specific Sublayer | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Tunnel Payload ... * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * L2TPv3 Session Header Over IP * * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Session ID | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Cookie (optional, maximum 64 bits)... * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * L2TPv3 L2-Specific Sublayer Format * * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |x|S|x|x|x|x|x|x| Sequence Number | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Cookie value and sublayer format are negotiated with the peer when * the session is set up. Unlike L2TPv2, we do not need to parse the * packet header to determine if optional fields are present. * * Caller must already have parsed the frame and determined that it is * a data (not control) frame before coming here. Fields up to the * session-id have already been parsed and ptr points to the data * after the session-id. */ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length) { struct l2tp_tunnel *tunnel = session->tunnel; int offset; /* Parse and check optional cookie */ if (session->peer_cookie_len > 0) { if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { pr_debug_ratelimited("%s: cookie mismatch (%u/%u). Discarding.\n", tunnel->name, tunnel->tunnel_id, session->session_id); atomic_long_inc(&session->stats.rx_cookie_discards); goto discard; } ptr += session->peer_cookie_len; } /* Handle the optional sequence numbers. Sequence numbers are * in different places for L2TPv2 and L2TPv3. * * If we are the LAC, enable/disable sequence numbers under * the control of the LNS. If no sequence numbers present but * we were expecting them, discard frame. */ L2TP_SKB_CB(skb)->has_seq = 0; if (tunnel->version == L2TP_HDR_VER_2) { if (hdrflags & L2TP_HDRFLAG_S) { /* Store L2TP info in the skb */ L2TP_SKB_CB(skb)->ns = ntohs(*(__be16 *)ptr); L2TP_SKB_CB(skb)->has_seq = 1; ptr += 2; /* Skip past nr in the header */ ptr += 2; } } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { u32 l2h = ntohl(*(__be32 *)ptr); if (l2h & 0x40000000) { /* Store L2TP info in the skb */ L2TP_SKB_CB(skb)->ns = l2h & 0x00ffffff; L2TP_SKB_CB(skb)->has_seq = 1; } ptr += 4; } if (L2TP_SKB_CB(skb)->has_seq) { /* Received a packet with sequence numbers. If we're the LAC, * check if we sre sending sequence numbers and if not, * configure it so. */ if (!session->lns_mode && !session->send_seq) { trace_session_seqnum_lns_enable(session); session->send_seq = 1; l2tp_session_set_header_len(session, tunnel->version); } } else { /* No sequence numbers. * If user has configured mandatory sequence numbers, discard. */ if (session->recv_seq) { pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n", session->name); atomic_long_inc(&session->stats.rx_seq_discards); goto discard; } /* If we're the LAC and we're sending sequence numbers, the * LNS has requested that we no longer send sequence numbers. * If we're the LNS and we're sending sequence numbers, the * LAC is broken. Discard the frame. */ if (!session->lns_mode && session->send_seq) { trace_session_seqnum_lns_disable(session); session->send_seq = 0; l2tp_session_set_header_len(session, tunnel->version); } else if (session->send_seq) { pr_debug_ratelimited("%s: recv data has no seq numbers when required. Discarding.\n", session->name); atomic_long_inc(&session->stats.rx_seq_discards); goto discard; } } /* Session data offset is defined only for L2TPv2 and is * indicated by an optional 16-bit value in the header. */ if (tunnel->version == L2TP_HDR_VER_2) { /* If offset bit set, skip it. */ if (hdrflags & L2TP_HDRFLAG_O) { offset = ntohs(*(__be16 *)ptr); ptr += 2 + offset; } } offset = ptr - optr; if (!pskb_may_pull(skb, offset)) goto discard; __skb_pull(skb, offset); /* Prepare skb for adding to the session's reorder_q. Hold * packets for max reorder_timeout or 1 second if not * reordering. */ L2TP_SKB_CB(skb)->length = length; L2TP_SKB_CB(skb)->expires = jiffies + (session->reorder_timeout ? session->reorder_timeout : HZ); /* Add packet to the session's receive queue. Reordering is done here, if * enabled. Saved L2TP protocol info is stored in skb->sb[]. */ if (L2TP_SKB_CB(skb)->has_seq) { if (l2tp_recv_data_seq(session, skb)) goto discard; } else { /* No sequence numbers. Add the skb to the tail of the * reorder queue. This ensures that it will be * delivered after all previous sequenced skbs. */ skb_queue_tail(&session->reorder_q, skb); } /* Try to dequeue as many skbs from reorder_q as we can. */ l2tp_recv_dequeue(session); return; discard: atomic_long_inc(&session->stats.rx_errors); kfree_skb(skb); } EXPORT_SYMBOL_GPL(l2tp_recv_common); /* Drop skbs from the session's reorder_q */ static void l2tp_session_queue_purge(struct l2tp_session *session) { struct sk_buff *skb = NULL; while ((skb = skb_dequeue(&session->reorder_q))) { atomic_long_inc(&session->stats.rx_errors); kfree_skb(skb); } } /* UDP encapsulation receive handler. See net/ipv4/udp.c for details. */ int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) { struct l2tp_session *session = NULL; struct l2tp_tunnel *tunnel = NULL; struct net *net = sock_net(sk); unsigned char *ptr, *optr; u16 hdrflags; u16 version; int length; /* UDP has verified checksum */ /* UDP always verifies the packet length. */ __skb_pull(skb, sizeof(struct udphdr)); /* Short packet? */ if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) goto pass; /* Point to L2TP header */ optr = skb->data; ptr = skb->data; /* Get L2TP header flags */ hdrflags = ntohs(*(__be16 *)ptr); /* Get protocol version */ version = hdrflags & L2TP_HDR_VER_MASK; /* Get length of L2TP packet */ length = skb->len; /* If type is control packet, it is handled by userspace. */ if (hdrflags & L2TP_HDRFLAG_T) goto pass; /* Skip flags */ ptr += 2; if (version == L2TP_HDR_VER_2) { u16 tunnel_id, session_id; /* If length is present, skip it */ if (hdrflags & L2TP_HDRFLAG_L) ptr += 2; /* Extract tunnel and session ID */ tunnel_id = ntohs(*(__be16 *)ptr); ptr += 2; session_id = ntohs(*(__be16 *)ptr); ptr += 2; session = l2tp_v2_session_get(net, tunnel_id, session_id); } else { u32 session_id; ptr += 2; /* skip reserved bits */ session_id = ntohl(*(__be32 *)ptr); ptr += 4; session = l2tp_v3_session_get(net, sk, session_id); } if (!session || !session->recv_skb) { if (session) l2tp_session_dec_refcount(session); /* Not found? Pass to userspace to deal with */ goto pass; } tunnel = session->tunnel; /* Check protocol version */ if (version != tunnel->version) goto invalid; if (version == L2TP_HDR_VER_3 && l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) { l2tp_session_dec_refcount(session); goto invalid; } l2tp_recv_common(session, skb, ptr, optr, hdrflags, length); l2tp_session_dec_refcount(session); return 0; invalid: atomic_long_inc(&tunnel->stats.rx_invalid); pass: /* Put UDP header back */ __skb_push(skb, sizeof(struct udphdr)); return 1; } EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); /* UDP encapsulation receive error handler. See net/ipv4/udp.c for details. */ static void l2tp_udp_encap_err_recv(struct sock *sk, struct sk_buff *skb, int err, __be16 port, u32 info, u8 *payload) { sk->sk_err = err; sk_error_report(sk); if (ip_hdr(skb)->version == IPVERSION) { if (inet_test_bit(RECVERR, sk)) return ip_icmp_error(sk, skb, err, port, info, payload); #if IS_ENABLED(CONFIG_IPV6) } else { if (inet6_test_bit(RECVERR6, sk)) return ipv6_icmp_error(sk, skb, err, port, info, payload); #endif } } /************************************************************************ * Transmit handling ***********************************************************************/ /* Build an L2TP header for the session into the buffer provided. */ static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) { struct l2tp_tunnel *tunnel = session->tunnel; __be16 *bufp = buf; __be16 *optr = buf; u16 flags = L2TP_HDR_VER_2; u32 tunnel_id = tunnel->peer_tunnel_id; u32 session_id = session->peer_session_id; if (session->send_seq) flags |= L2TP_HDRFLAG_S; /* Setup L2TP header. */ *bufp++ = htons(flags); *bufp++ = htons(tunnel_id); *bufp++ = htons(session_id); if (session->send_seq) { *bufp++ = htons(session->ns); *bufp++ = 0; session->ns++; session->ns &= 0xffff; trace_session_seqnum_update(session); } return bufp - optr; } static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) { struct l2tp_tunnel *tunnel = session->tunnel; char *bufp = buf; char *optr = bufp; /* Setup L2TP header. The header differs slightly for UDP and * IP encapsulations. For UDP, there is 4 bytes of flags. */ if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { u16 flags = L2TP_HDR_VER_3; *((__be16 *)bufp) = htons(flags); bufp += 2; *((__be16 *)bufp) = 0; bufp += 2; } *((__be32 *)bufp) = htonl(session->peer_session_id); bufp += 4; if (session->cookie_len) { memcpy(bufp, &session->cookie[0], session->cookie_len); bufp += session->cookie_len; } if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { u32 l2h = 0; if (session->send_seq) { l2h = 0x40000000 | session->ns; session->ns++; session->ns &= 0xffffff; trace_session_seqnum_update(session); } *((__be32 *)bufp) = htonl(l2h); bufp += 4; } return bufp - optr; } /* Queue the packet to IP for output: tunnel socket lock must be held */ static int l2tp_xmit_queue(struct l2tp_tunnel *tunnel, struct sk_buff *skb, struct flowi *fl) { int err; skb->ignore_df = 1; skb_dst_drop(skb); #if IS_ENABLED(CONFIG_IPV6) if (l2tp_sk_is_v6(tunnel->sock)) err = inet6_csk_xmit(tunnel->sock, skb, NULL); else #endif err = ip_queue_xmit(tunnel->sock, skb, fl); return err >= 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP; } static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, unsigned int *len) { struct l2tp_tunnel *tunnel = session->tunnel; unsigned int data_len = skb->len; struct sock *sk = tunnel->sock; int headroom, uhlen, udp_len; int ret = NET_XMIT_SUCCESS; struct inet_sock *inet; struct udphdr *uh; /* Check that there's enough headroom in the skb to insert IP, * UDP and L2TP headers. If not enough, expand it to * make room. Adjust truesize. */ uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(*uh) : 0; headroom = NET_SKB_PAD + sizeof(struct iphdr) + uhlen + session->hdr_len; if (skb_cow_head(skb, headroom)) { kfree_skb(skb); return NET_XMIT_DROP; } /* Setup L2TP header */ if (tunnel->version == L2TP_HDR_VER_2) l2tp_build_l2tpv2_header(session, __skb_push(skb, session->hdr_len)); else l2tp_build_l2tpv3_header(session, __skb_push(skb, session->hdr_len)); /* Reset skb netfilter state */ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); nf_reset_ct(skb); /* L2TP uses its own lockdep subclass to avoid lockdep splats caused by * nested socket calls on the same lockdep socket class. This can * happen when data from a user socket is routed over l2tp, which uses * another userspace socket. */ spin_lock_nested(&sk->sk_lock.slock, L2TP_DEPTH_NESTING); if (sock_owned_by_user(sk)) { kfree_skb(skb); ret = NET_XMIT_DROP; goto out_unlock; } /* The user-space may change the connection status for the user-space * provided socket at run time: we must check it under the socket lock */ if (tunnel->fd >= 0 && sk->sk_state != TCP_ESTABLISHED) { kfree_skb(skb); ret = NET_XMIT_DROP; goto out_unlock; } /* Report transmitted length before we add encap header, which keeps * statistics consistent for both UDP and IP encap tx/rx paths. */ *len = skb->len; inet = inet_sk(sk); switch (tunnel->encap) { case L2TP_ENCAPTYPE_UDP: /* Setup UDP header */ __skb_push(skb, sizeof(*uh)); skb_reset_transport_header(skb); uh = udp_hdr(skb); uh->source = inet->inet_sport; uh->dest = inet->inet_dport; udp_len = uhlen + session->hdr_len + data_len; uh->len = htons(udp_len); /* Calculate UDP checksum if configured to do so */ #if IS_ENABLED(CONFIG_IPV6) if (l2tp_sk_is_v6(sk)) udp6_set_csum(udp_get_no_check6_tx(sk), skb, &inet6_sk(sk)->saddr, &sk->sk_v6_daddr, udp_len); else #endif udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr, inet->inet_daddr, udp_len); break; case L2TP_ENCAPTYPE_IP: break; } ret = l2tp_xmit_queue(tunnel, skb, &inet->cork.fl); out_unlock: spin_unlock(&sk->sk_lock.slock); return ret; } /* If caller requires the skb to have a ppp header, the header must be * inserted in the skb data before calling this function. */ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) { unsigned int len = 0; int ret; ret = l2tp_xmit_core(session, skb, &len); if (ret == NET_XMIT_SUCCESS) { atomic_long_inc(&session->tunnel->stats.tx_packets); atomic_long_add(len, &session->tunnel->stats.tx_bytes); atomic_long_inc(&session->stats.tx_packets); atomic_long_add(len, &session->stats.tx_bytes); } else { atomic_long_inc(&session->tunnel->stats.tx_errors); atomic_long_inc(&session->stats.tx_errors); } return ret; } EXPORT_SYMBOL_GPL(l2tp_xmit_skb); /***************************************************************************** * Tinnel and session create/destroy. *****************************************************************************/ /* Tunnel socket destruct hook. * The tunnel context is deleted only when all session sockets have been * closed. */ static void l2tp_tunnel_destruct(struct sock *sk) { struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk); if (!tunnel) goto end; /* Disable udp encapsulation */ switch (tunnel->encap) { case L2TP_ENCAPTYPE_UDP: /* No longer an encapsulation socket. See net/ipv4/udp.c */ WRITE_ONCE(udp_sk(sk)->encap_type, 0); udp_sk(sk)->encap_rcv = NULL; udp_sk(sk)->encap_destroy = NULL; break; case L2TP_ENCAPTYPE_IP: break; } /* Remove hooks into tunnel socket */ write_lock_bh(&sk->sk_callback_lock); sk->sk_destruct = tunnel->old_sk_destruct; sk->sk_user_data = NULL; write_unlock_bh(&sk->sk_callback_lock); /* Call the original destructor */ if (sk->sk_destruct) (*sk->sk_destruct)(sk); kfree_rcu(tunnel, rcu); end: return; } /* Remove an l2tp session from l2tp_core's lists. */ static void l2tp_session_unhash(struct l2tp_session *session) { struct l2tp_tunnel *tunnel = session->tunnel; if (tunnel) { struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); struct l2tp_session *removed = session; spin_lock_bh(&tunnel->list_lock); spin_lock_bh(&pn->l2tp_session_idr_lock); /* Remove from the per-tunnel list */ list_del_init(&session->list); /* Remove from per-net IDR */ if (tunnel->version == L2TP_HDR_VER_3) { if (hash_hashed(&session->hlist)) l2tp_session_collision_del(pn, session); else removed = idr_remove(&pn->l2tp_v3_session_idr, session->session_id); } else { u32 session_key = l2tp_v2_session_key(tunnel->tunnel_id, session->session_id); removed = idr_remove(&pn->l2tp_v2_session_idr, session_key); } WARN_ON_ONCE(removed && removed != session); spin_unlock_bh(&pn->l2tp_session_idr_lock); spin_unlock_bh(&tunnel->list_lock); synchronize_rcu(); } } /* When the tunnel is closed, all the attached sessions need to go too. */ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) { struct l2tp_session *session; spin_lock_bh(&tunnel->list_lock); tunnel->acpt_newsess = false; for (;;) { session = list_first_entry_or_null(&tunnel->session_list, struct l2tp_session, list); if (!session) break; l2tp_session_inc_refcount(session); list_del_init(&session->list); spin_unlock_bh(&tunnel->list_lock); l2tp_session_delete(session); spin_lock_bh(&tunnel->list_lock); l2tp_session_dec_refcount(session); } spin_unlock_bh(&tunnel->list_lock); } /* Tunnel socket destroy hook for UDP encapsulation */ static void l2tp_udp_encap_destroy(struct sock *sk) { struct l2tp_tunnel *tunnel = l2tp_sk_to_tunnel(sk); if (tunnel) l2tp_tunnel_delete(tunnel); } static void l2tp_tunnel_remove(struct net *net, struct l2tp_tunnel *tunnel) { struct l2tp_net *pn = l2tp_pernet(net); spin_lock_bh(&pn->l2tp_tunnel_idr_lock); idr_remove(&pn->l2tp_tunnel_idr, tunnel->tunnel_id); spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); } /* Workqueue tunnel deletion function */ static void l2tp_tunnel_del_work(struct work_struct *work) { struct l2tp_tunnel *tunnel = container_of(work, struct l2tp_tunnel, del_work); struct sock *sk = tunnel->sock; struct socket *sock = sk->sk_socket; l2tp_tunnel_closeall(tunnel); /* If the tunnel socket was created within the kernel, use * the sk API to release it here. */ if (tunnel->fd < 0) { if (sock) { kernel_sock_shutdown(sock, SHUT_RDWR); sock_release(sock); } } l2tp_tunnel_remove(tunnel->l2tp_net, tunnel); /* drop initial ref */ l2tp_tunnel_dec_refcount(tunnel); /* drop workqueue ref */ l2tp_tunnel_dec_refcount(tunnel); } /* Create a socket for the tunnel, if one isn't set up by * userspace. This is used for static tunnels where there is no * managing L2TP daemon. * * Since we don't want these sockets to keep a namespace alive by * themselves, we drop the socket's namespace refcount after creation. * These sockets are freed when the namespace exits using the pernet * exit hook. */ static int l2tp_tunnel_sock_create(struct net *net, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) { int err = -EINVAL; struct socket *sock = NULL; struct udp_port_cfg udp_conf; switch (cfg->encap) { case L2TP_ENCAPTYPE_UDP: memset(&udp_conf, 0, sizeof(udp_conf)); #if IS_ENABLED(CONFIG_IPV6) if (cfg->local_ip6 && cfg->peer_ip6) { udp_conf.family = AF_INET6; memcpy(&udp_conf.local_ip6, cfg->local_ip6, sizeof(udp_conf.local_ip6)); memcpy(&udp_conf.peer_ip6, cfg->peer_ip6, sizeof(udp_conf.peer_ip6)); udp_conf.use_udp6_tx_checksums = !cfg->udp6_zero_tx_checksums; udp_conf.use_udp6_rx_checksums = !cfg->udp6_zero_rx_checksums; } else #endif { udp_conf.family = AF_INET; udp_conf.local_ip = cfg->local_ip; udp_conf.peer_ip = cfg->peer_ip; udp_conf.use_udp_checksums = cfg->use_udp_checksums; } udp_conf.local_udp_port = htons(cfg->local_udp_port); udp_conf.peer_udp_port = htons(cfg->peer_udp_port); err = udp_sock_create(net, &udp_conf, &sock); if (err < 0) goto out; break; case L2TP_ENCAPTYPE_IP: #if IS_ENABLED(CONFIG_IPV6) if (cfg->local_ip6 && cfg->peer_ip6) { struct sockaddr_l2tpip6 ip6_addr = {0}; err = sock_create_kern(net, AF_INET6, SOCK_DGRAM, IPPROTO_L2TP, &sock); if (err < 0) goto out; ip6_addr.l2tp_family = AF_INET6; memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, sizeof(ip6_addr.l2tp_addr)); ip6_addr.l2tp_conn_id = tunnel_id; err = kernel_bind(sock, (struct sockaddr *)&ip6_addr, sizeof(ip6_addr)); if (err < 0) goto out; ip6_addr.l2tp_family = AF_INET6; memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, sizeof(ip6_addr.l2tp_addr)); ip6_addr.l2tp_conn_id = peer_tunnel_id; err = kernel_connect(sock, (struct sockaddr *)&ip6_addr, sizeof(ip6_addr), 0); if (err < 0) goto out; } else #endif { struct sockaddr_l2tpip ip_addr = {0}; err = sock_create_kern(net, AF_INET, SOCK_DGRAM, IPPROTO_L2TP, &sock); if (err < 0) goto out; ip_addr.l2tp_family = AF_INET; ip_addr.l2tp_addr = cfg->local_ip; ip_addr.l2tp_conn_id = tunnel_id; err = kernel_bind(sock, (struct sockaddr *)&ip_addr, sizeof(ip_addr)); if (err < 0) goto out; ip_addr.l2tp_family = AF_INET; ip_addr.l2tp_addr = cfg->peer_ip; ip_addr.l2tp_conn_id = peer_tunnel_id; err = kernel_connect(sock, (struct sockaddr *)&ip_addr, sizeof(ip_addr), 0); if (err < 0) goto out; } break; default: goto out; } out: *sockp = sock; if (err < 0 && sock) { kernel_sock_shutdown(sock, SHUT_RDWR); sock_release(sock); *sockp = NULL; } return err; } int l2tp_tunnel_create(int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) { struct l2tp_tunnel *tunnel = NULL; int err; enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; if (cfg) encap = cfg->encap; tunnel = kzalloc(sizeof(*tunnel), GFP_KERNEL); if (!tunnel) { err = -ENOMEM; goto err; } tunnel->version = version; tunnel->tunnel_id = tunnel_id; tunnel->peer_tunnel_id = peer_tunnel_id; tunnel->magic = L2TP_TUNNEL_MAGIC; sprintf(&tunnel->name[0], "tunl %u", tunnel_id); spin_lock_init(&tunnel->list_lock); tunnel->acpt_newsess = true; INIT_LIST_HEAD(&tunnel->session_list); tunnel->encap = encap; refcount_set(&tunnel->ref_count, 1); tunnel->fd = fd; /* Init delete workqueue struct */ INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work); err = 0; err: if (tunnelp) *tunnelp = tunnel; return err; } EXPORT_SYMBOL_GPL(l2tp_tunnel_create); static int l2tp_validate_socket(const struct sock *sk, const struct net *net, enum l2tp_encap_type encap) { if (!net_eq(sock_net(sk), net)) return -EINVAL; if (sk->sk_type != SOCK_DGRAM) return -EPROTONOSUPPORT; if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6) return -EPROTONOSUPPORT; if ((encap == L2TP_ENCAPTYPE_UDP && sk->sk_protocol != IPPROTO_UDP) || (encap == L2TP_ENCAPTYPE_IP && sk->sk_protocol != IPPROTO_L2TP)) return -EPROTONOSUPPORT; if (sk->sk_user_data) return -EBUSY; return 0; } int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, struct l2tp_tunnel_cfg *cfg) { struct l2tp_net *pn = l2tp_pernet(net); u32 tunnel_id = tunnel->tunnel_id; struct socket *sock; struct sock *sk; int ret; spin_lock_bh(&pn->l2tp_tunnel_idr_lock); ret = idr_alloc_u32(&pn->l2tp_tunnel_idr, NULL, &tunnel_id, tunnel_id, GFP_ATOMIC); spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); if (ret) return ret == -ENOSPC ? -EEXIST : ret; if (tunnel->fd < 0) { ret = l2tp_tunnel_sock_create(net, tunnel->tunnel_id, tunnel->peer_tunnel_id, cfg, &sock); if (ret < 0) goto err; } else { sock = sockfd_lookup(tunnel->fd, &ret); if (!sock) goto err; } sk = sock->sk; lock_sock(sk); write_lock_bh(&sk->sk_callback_lock); ret = l2tp_validate_socket(sk, net, tunnel->encap); if (ret < 0) goto err_inval_sock; rcu_assign_sk_user_data(sk, tunnel); write_unlock_bh(&sk->sk_callback_lock); if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { struct udp_tunnel_sock_cfg udp_cfg = { .sk_user_data = tunnel, .encap_type = UDP_ENCAP_L2TPINUDP, .encap_rcv = l2tp_udp_encap_recv, .encap_err_rcv = l2tp_udp_encap_err_recv, .encap_destroy = l2tp_udp_encap_destroy, }; setup_udp_tunnel_sock(net, sock, &udp_cfg); } tunnel->old_sk_destruct = sk->sk_destruct; sk->sk_destruct = &l2tp_tunnel_destruct; sk->sk_allocation = GFP_ATOMIC; release_sock(sk); sock_hold(sk); tunnel->sock = sk; tunnel->l2tp_net = net; spin_lock_bh(&pn->l2tp_tunnel_idr_lock); idr_replace(&pn->l2tp_tunnel_idr, tunnel, tunnel->tunnel_id); spin_unlock_bh(&pn->l2tp_tunnel_idr_lock); trace_register_tunnel(tunnel); if (tunnel->fd >= 0) sockfd_put(sock); return 0; err_inval_sock: write_unlock_bh(&sk->sk_callback_lock); release_sock(sk); if (tunnel->fd < 0) sock_release(sock); else sockfd_put(sock); err: l2tp_tunnel_remove(net, tunnel); return ret; } EXPORT_SYMBOL_GPL(l2tp_tunnel_register); /* This function is used by the netlink TUNNEL_DELETE command. */ void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) { if (!test_and_set_bit(0, &tunnel->dead)) { trace_delete_tunnel(tunnel); l2tp_tunnel_inc_refcount(tunnel); queue_work(l2tp_wq, &tunnel->del_work); } } EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); void l2tp_session_delete(struct l2tp_session *session) { if (test_and_set_bit(0, &session->dead)) return; trace_delete_session(session); l2tp_session_unhash(session); l2tp_session_queue_purge(session); if (session->session_close) (*session->session_close)(session); l2tp_session_dec_refcount(session); } EXPORT_SYMBOL_GPL(l2tp_session_delete); /* We come here whenever a session's send_seq, cookie_len or * l2specific_type parameters are set. */ void l2tp_session_set_header_len(struct l2tp_session *session, int version) { if (version == L2TP_HDR_VER_2) { session->hdr_len = 6; if (session->send_seq) session->hdr_len += 4; } else { session->hdr_len = 4 + session->cookie_len; session->hdr_len += l2tp_get_l2specific_len(session); if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) session->hdr_len += 4; } } EXPORT_SYMBOL_GPL(l2tp_session_set_header_len); 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) { struct l2tp_session *session; session = kzalloc(sizeof(*session) + priv_size, GFP_KERNEL); if (session) { session->magic = L2TP_SESSION_MAGIC; session->tunnel = tunnel; session->session_id = session_id; session->peer_session_id = peer_session_id; session->nr = 0; if (tunnel->version == L2TP_HDR_VER_2) session->nr_max = 0xffff; else session->nr_max = 0xffffff; session->nr_window_size = session->nr_max / 2; session->nr_oos_count_max = 4; /* Use NR of first received packet */ session->reorder_skip = 1; sprintf(&session->name[0], "sess %u/%u", tunnel->tunnel_id, session->session_id); skb_queue_head_init(&session->reorder_q); session->hlist_key = l2tp_v3_session_hashkey(tunnel->sock, session->session_id); INIT_HLIST_NODE(&session->hlist); INIT_LIST_HEAD(&session->clist); INIT_LIST_HEAD(&session->list); if (cfg) { session->pwtype = cfg->pw_type; session->send_seq = cfg->send_seq; session->recv_seq = cfg->recv_seq; session->lns_mode = cfg->lns_mode; session->reorder_timeout = cfg->reorder_timeout; session->l2specific_type = cfg->l2specific_type; session->cookie_len = cfg->cookie_len; memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); session->peer_cookie_len = cfg->peer_cookie_len; memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); } l2tp_session_set_header_len(session, tunnel->version); refcount_set(&session->ref_count, 1); return session; } return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(l2tp_session_create); /***************************************************************************** * Init and cleanup *****************************************************************************/ static __net_init int l2tp_init_net(struct net *net) { struct l2tp_net *pn = net_generic(net, l2tp_net_id); idr_init(&pn->l2tp_tunnel_idr); spin_lock_init(&pn->l2tp_tunnel_idr_lock); idr_init(&pn->l2tp_v2_session_idr); idr_init(&pn->l2tp_v3_session_idr); spin_lock_init(&pn->l2tp_session_idr_lock); return 0; } static __net_exit void l2tp_exit_net(struct net *net) { struct l2tp_net *pn = l2tp_pernet(net); struct l2tp_tunnel *tunnel = NULL; unsigned long tunnel_id, tmp; rcu_read_lock_bh(); idr_for_each_entry_ul(&pn->l2tp_tunnel_idr, tunnel, tmp, tunnel_id) { if (tunnel) l2tp_tunnel_delete(tunnel); } rcu_read_unlock_bh(); if (l2tp_wq) flush_workqueue(l2tp_wq); rcu_barrier(); idr_destroy(&pn->l2tp_v2_session_idr); idr_destroy(&pn->l2tp_v3_session_idr); idr_destroy(&pn->l2tp_tunnel_idr); } static struct pernet_operations l2tp_net_ops = { .init = l2tp_init_net, .exit = l2tp_exit_net, .id = &l2tp_net_id, .size = sizeof(struct l2tp_net), }; static int __init l2tp_init(void) { int rc = 0; rc = register_pernet_device(&l2tp_net_ops); if (rc) goto out; l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0); if (!l2tp_wq) { pr_err("alloc_workqueue failed\n"); unregister_pernet_device(&l2tp_net_ops); rc = -ENOMEM; goto out; } pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION); out: return rc; } static void __exit l2tp_exit(void) { unregister_pernet_device(&l2tp_net_ops); if (l2tp_wq) { destroy_workqueue(l2tp_wq); l2tp_wq = NULL; } } module_init(l2tp_init); module_exit(l2tp_exit); MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); MODULE_DESCRIPTION("L2TP core"); MODULE_LICENSE("GPL"); MODULE_VERSION(L2TP_DRV_VERSION);
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