![stephen hemminger](/assets/img/avatar_default.png)
Avoid needless export of local functions Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Acked-by: James Chapman <jchapman@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2049 lines
55 KiB
C
2049 lines
55 KiB
C
/*
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* L2TP core.
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*
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* Copyright (c) 2008,2009,2010 Katalix Systems Ltd
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*
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* This file contains some code of the original L2TPv2 pppol2tp
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* driver, which has the following copyright:
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*
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* Authors: Martijn van Oosterhout <kleptog@svana.org>
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* James Chapman (jchapman@katalix.com)
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* Contributors:
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* Michal Ostrowski <mostrows@speakeasy.net>
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* Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
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* David S. Miller (davem@redhat.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/list.h>
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#include <linux/rculist.h>
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/kthread.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/jiffies.h>
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#include <linux/netdevice.h>
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#include <linux/net.h>
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#include <linux/inetdevice.h>
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#include <linux/skbuff.h>
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#include <linux/init.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/l2tp.h>
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#include <linux/hash.h>
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#include <linux/sort.h>
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#include <linux/file.h>
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#include <linux/nsproxy.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <net/dst.h>
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#include <net/ip.h>
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#include <net/udp.h>
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#include <net/inet_common.h>
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#include <net/xfrm.h>
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#include <net/protocol.h>
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#include <net/inet6_connection_sock.h>
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#include <net/inet_ecn.h>
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#include <net/ip6_route.h>
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#include <net/ip6_checksum.h>
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#include <asm/byteorder.h>
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#include <linux/atomic.h>
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#include "l2tp_core.h"
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#define L2TP_DRV_VERSION "V2.0"
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/* L2TP header constants */
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#define L2TP_HDRFLAG_T 0x8000
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#define L2TP_HDRFLAG_L 0x4000
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#define L2TP_HDRFLAG_S 0x0800
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#define L2TP_HDRFLAG_O 0x0200
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#define L2TP_HDRFLAG_P 0x0100
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#define L2TP_HDR_VER_MASK 0x000F
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#define L2TP_HDR_VER_2 0x0002
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#define L2TP_HDR_VER_3 0x0003
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/* L2TPv3 default L2-specific sublayer */
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#define L2TP_SLFLAG_S 0x40000000
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#define L2TP_SL_SEQ_MASK 0x00ffffff
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#define L2TP_HDR_SIZE_SEQ 10
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#define L2TP_HDR_SIZE_NOSEQ 6
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/* Default trace flags */
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#define L2TP_DEFAULT_DEBUG_FLAGS 0
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/* Private data stored for received packets in the skb.
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*/
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struct l2tp_skb_cb {
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u32 ns;
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u16 has_seq;
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u16 length;
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unsigned long expires;
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};
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#define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
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static atomic_t l2tp_tunnel_count;
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static atomic_t l2tp_session_count;
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static struct workqueue_struct *l2tp_wq;
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/* per-net private data for this module */
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static unsigned int l2tp_net_id;
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struct l2tp_net {
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struct list_head l2tp_tunnel_list;
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spinlock_t l2tp_tunnel_list_lock;
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struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
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spinlock_t l2tp_session_hlist_lock;
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};
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static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
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static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
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static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
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{
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return sk->sk_user_data;
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}
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static inline struct l2tp_net *l2tp_pernet(struct net *net)
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{
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BUG_ON(!net);
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return net_generic(net, l2tp_net_id);
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}
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/* Tunnel reference counts. Incremented per session that is added to
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* the tunnel.
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*/
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static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel)
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{
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atomic_inc(&tunnel->ref_count);
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}
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static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
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{
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if (atomic_dec_and_test(&tunnel->ref_count))
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l2tp_tunnel_free(tunnel);
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}
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#ifdef L2TP_REFCNT_DEBUG
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#define l2tp_tunnel_inc_refcount(_t) \
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do { \
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pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", \
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__func__, __LINE__, (_t)->name, \
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atomic_read(&_t->ref_count)); \
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l2tp_tunnel_inc_refcount_1(_t); \
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} while (0)
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#define l2tp_tunnel_dec_refcount(_t)
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do { \
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pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", \
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__func__, __LINE__, (_t)->name, \
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atomic_read(&_t->ref_count)); \
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l2tp_tunnel_dec_refcount_1(_t); \
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} while (0)
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#else
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#define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
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#define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
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#endif
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/* Session hash global list for L2TPv3.
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* The session_id SHOULD be random according to RFC3931, but several
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* L2TP implementations use incrementing session_ids. So we do a real
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* hash on the session_id, rather than a simple bitmask.
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*/
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static inline struct hlist_head *
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l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
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{
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return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)];
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}
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/* Lookup the tunnel socket, possibly involving the fs code if the socket is
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* owned by userspace. A struct sock returned from this function must be
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* released using l2tp_tunnel_sock_put once you're done with it.
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*/
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static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
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{
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int err = 0;
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struct socket *sock = NULL;
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struct sock *sk = NULL;
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if (!tunnel)
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goto out;
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if (tunnel->fd >= 0) {
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/* Socket is owned by userspace, who might be in the process
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* of closing it. Look the socket up using the fd to ensure
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* consistency.
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*/
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sock = sockfd_lookup(tunnel->fd, &err);
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if (sock)
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sk = sock->sk;
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} else {
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/* Socket is owned by kernelspace */
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sk = tunnel->sock;
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sock_hold(sk);
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}
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out:
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return sk;
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}
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/* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
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static void l2tp_tunnel_sock_put(struct sock *sk)
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{
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struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
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if (tunnel) {
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if (tunnel->fd >= 0) {
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/* Socket is owned by userspace */
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sockfd_put(sk->sk_socket);
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}
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sock_put(sk);
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}
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sock_put(sk);
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}
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/* Lookup a session by id in the global session list
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*/
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static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
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{
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struct l2tp_net *pn = l2tp_pernet(net);
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struct hlist_head *session_list =
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l2tp_session_id_hash_2(pn, session_id);
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struct l2tp_session *session;
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rcu_read_lock_bh();
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hlist_for_each_entry_rcu(session, session_list, global_hlist) {
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if (session->session_id == session_id) {
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rcu_read_unlock_bh();
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return session;
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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/* Session hash list.
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* The session_id SHOULD be random according to RFC2661, but several
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* L2TP implementations (Cisco and Microsoft) use incrementing
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* session_ids. So we do a real hash on the session_id, rather than a
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* simple bitmask.
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*/
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static inline struct hlist_head *
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l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
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{
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return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
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}
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/* Lookup a session by id
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*/
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struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
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{
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struct hlist_head *session_list;
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struct l2tp_session *session;
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/* In L2TPv3, session_ids are unique over all tunnels and we
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* sometimes need to look them up before we know the
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* tunnel.
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*/
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if (tunnel == NULL)
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return l2tp_session_find_2(net, session_id);
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session_list = l2tp_session_id_hash(tunnel, session_id);
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read_lock_bh(&tunnel->hlist_lock);
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hlist_for_each_entry(session, session_list, hlist) {
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if (session->session_id == session_id) {
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read_unlock_bh(&tunnel->hlist_lock);
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return session;
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}
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}
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read_unlock_bh(&tunnel->hlist_lock);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_find);
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struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
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{
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int hash;
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struct l2tp_session *session;
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int count = 0;
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read_lock_bh(&tunnel->hlist_lock);
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for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
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hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
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if (++count > nth) {
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read_unlock_bh(&tunnel->hlist_lock);
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return session;
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}
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}
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}
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read_unlock_bh(&tunnel->hlist_lock);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_find_nth);
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/* Lookup a session by interface name.
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* This is very inefficient but is only used by management interfaces.
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*/
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struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
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{
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struct l2tp_net *pn = l2tp_pernet(net);
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int hash;
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struct l2tp_session *session;
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rcu_read_lock_bh();
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for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
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hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
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if (!strcmp(session->ifname, ifname)) {
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rcu_read_unlock_bh();
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return session;
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}
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname);
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/* Lookup a tunnel by id
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*/
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struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id)
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{
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struct l2tp_tunnel *tunnel;
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struct l2tp_net *pn = l2tp_pernet(net);
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rcu_read_lock_bh();
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list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
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if (tunnel->tunnel_id == tunnel_id) {
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rcu_read_unlock_bh();
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return tunnel;
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_find);
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struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth)
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{
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struct l2tp_net *pn = l2tp_pernet(net);
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struct l2tp_tunnel *tunnel;
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int count = 0;
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rcu_read_lock_bh();
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list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
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if (++count > nth) {
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rcu_read_unlock_bh();
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return tunnel;
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}
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}
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rcu_read_unlock_bh();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth);
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/*****************************************************************************
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* Receive data handling
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*****************************************************************************/
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/* Queue a skb in order. We come here only if the skb has an L2TP sequence
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* number.
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*/
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static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb)
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{
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struct sk_buff *skbp;
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struct sk_buff *tmp;
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u32 ns = L2TP_SKB_CB(skb)->ns;
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spin_lock_bh(&session->reorder_q.lock);
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skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
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if (L2TP_SKB_CB(skbp)->ns > ns) {
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__skb_queue_before(&session->reorder_q, skbp, skb);
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l2tp_dbg(session, L2TP_MSG_SEQ,
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"%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
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session->name, ns, L2TP_SKB_CB(skbp)->ns,
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skb_queue_len(&session->reorder_q));
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atomic_long_inc(&session->stats.rx_oos_packets);
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goto out;
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}
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}
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__skb_queue_tail(&session->reorder_q, skb);
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out:
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spin_unlock_bh(&session->reorder_q.lock);
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}
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/* Dequeue a single skb.
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*/
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static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb)
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{
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struct l2tp_tunnel *tunnel = session->tunnel;
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int length = L2TP_SKB_CB(skb)->length;
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/* We're about to requeue the skb, so return resources
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* to its current owner (a socket receive buffer).
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*/
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skb_orphan(skb);
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atomic_long_inc(&tunnel->stats.rx_packets);
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atomic_long_add(length, &tunnel->stats.rx_bytes);
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atomic_long_inc(&session->stats.rx_packets);
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atomic_long_add(length, &session->stats.rx_bytes);
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if (L2TP_SKB_CB(skb)->has_seq) {
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/* Bump our Nr */
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session->nr++;
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session->nr &= session->nr_max;
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l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
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session->name, session->nr);
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}
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/* call private receive handler */
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if (session->recv_skb != NULL)
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(*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
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else
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kfree_skb(skb);
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if (session->deref)
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(*session->deref)(session);
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}
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/* Dequeue skbs from the session's reorder_q, subject to packet order.
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* Skbs that have been in the queue for too long are simply discarded.
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*/
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static void l2tp_recv_dequeue(struct l2tp_session *session)
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{
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struct sk_buff *skb;
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struct sk_buff *tmp;
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|
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/* If the pkt at the head of the queue has the nr that we
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* expect to send up next, dequeue it and any other
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* in-sequence packets behind it.
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*/
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start:
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spin_lock_bh(&session->reorder_q.lock);
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skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
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if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
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atomic_long_inc(&session->stats.rx_seq_discards);
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atomic_long_inc(&session->stats.rx_errors);
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l2tp_dbg(session, L2TP_MSG_SEQ,
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"%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
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session->name, L2TP_SKB_CB(skb)->ns,
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L2TP_SKB_CB(skb)->length, session->nr,
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skb_queue_len(&session->reorder_q));
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session->reorder_skip = 1;
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__skb_unlink(skb, &session->reorder_q);
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kfree_skb(skb);
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if (session->deref)
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(*session->deref)(session);
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continue;
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}
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|
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if (L2TP_SKB_CB(skb)->has_seq) {
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if (session->reorder_skip) {
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l2tp_dbg(session, L2TP_MSG_SEQ,
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"%s: advancing nr to next pkt: %u -> %u",
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session->name, session->nr,
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L2TP_SKB_CB(skb)->ns);
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session->reorder_skip = 0;
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session->nr = L2TP_SKB_CB(skb)->ns;
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}
|
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if (L2TP_SKB_CB(skb)->ns != session->nr) {
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l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
|
|
session->name, L2TP_SKB_CB(skb)->ns,
|
|
L2TP_SKB_CB(skb)->length, session->nr,
|
|
skb_queue_len(&session->reorder_q));
|
|
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 inline int l2tp_verify_udp_checksum(struct sock *sk,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct udphdr *uh = udp_hdr(skb);
|
|
u16 ulen = ntohs(uh->len);
|
|
__wsum psum;
|
|
|
|
if (sk->sk_no_check || skb_csum_unnecessary(skb))
|
|
return 0;
|
|
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (sk->sk_family == PF_INET6 && !l2tp_tunnel(sk)->v4mapped) {
|
|
if (!uh->check) {
|
|
LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
|
|
return 1;
|
|
}
|
|
if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
|
|
!csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
|
|
&ipv6_hdr(skb)->daddr, ulen,
|
|
IPPROTO_UDP, skb->csum)) {
|
|
skb->ip_summed = CHECKSUM_UNNECESSARY;
|
|
return 0;
|
|
}
|
|
skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
|
|
&ipv6_hdr(skb)->daddr,
|
|
skb->len, IPPROTO_UDP,
|
|
0));
|
|
} else
|
|
#endif
|
|
{
|
|
struct inet_sock *inet;
|
|
if (!uh->check)
|
|
return 0;
|
|
inet = inet_sk(sk);
|
|
psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
|
|
ulen, IPPROTO_UDP, 0);
|
|
|
|
if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
|
|
!csum_fold(csum_add(psum, skb->csum)))
|
|
return 0;
|
|
skb->csum = psum;
|
|
}
|
|
|
|
return __skb_checksum_complete(skb);
|
|
}
|
|
|
|
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)
|
|
{
|
|
if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
|
|
/* Packet sequence number is outside allowed window.
|
|
* Discard it.
|
|
*/
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: pkt %u len %d discarded, outside window, nr=%u\n",
|
|
session->name, L2TP_SKB_CB(skb)->ns,
|
|
L2TP_SKB_CB(skb)->length, session->nr);
|
|
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 (L2TP_SKB_CB(skb)->ns == session->nr) {
|
|
skb_queue_tail(&session->reorder_q, skb);
|
|
} else {
|
|
u32 nr_oos = L2TP_SKB_CB(skb)->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;
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: %d oos packets received. Resetting sequence numbers\n",
|
|
session->name, session->nr_oos_count);
|
|
}
|
|
if (!session->reorder_skip) {
|
|
atomic_long_inc(&session->stats.rx_seq_discards);
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
|
|
session->name, L2TP_SKB_CB(skb)->ns,
|
|
L2TP_SKB_CB(skb)->length, session->nr,
|
|
skb_queue_len(&session->reorder_q));
|
|
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, sublayer format and offset (pad) 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, int (*payload_hook)(struct sk_buff *skb))
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
int offset;
|
|
u32 ns, nr;
|
|
|
|
/* The ref count is increased since we now hold a pointer to
|
|
* the session. Take care to decrement the refcnt when exiting
|
|
* this function from now on...
|
|
*/
|
|
l2tp_session_inc_refcount(session);
|
|
if (session->ref)
|
|
(*session->ref)(session);
|
|
|
|
/* Parse and check optional cookie */
|
|
if (session->peer_cookie_len > 0) {
|
|
if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
|
|
l2tp_info(tunnel, L2TP_MSG_DATA,
|
|
"%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.
|
|
*/
|
|
ns = nr = 0;
|
|
L2TP_SKB_CB(skb)->has_seq = 0;
|
|
if (tunnel->version == L2TP_HDR_VER_2) {
|
|
if (hdrflags & L2TP_HDRFLAG_S) {
|
|
ns = ntohs(*(__be16 *) ptr);
|
|
ptr += 2;
|
|
nr = ntohs(*(__be16 *) ptr);
|
|
ptr += 2;
|
|
|
|
/* Store L2TP info in the skb */
|
|
L2TP_SKB_CB(skb)->ns = ns;
|
|
L2TP_SKB_CB(skb)->has_seq = 1;
|
|
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: recv data ns=%u, nr=%u, session nr=%u\n",
|
|
session->name, ns, nr, session->nr);
|
|
}
|
|
} else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
|
|
u32 l2h = ntohl(*(__be32 *) ptr);
|
|
|
|
if (l2h & 0x40000000) {
|
|
ns = l2h & 0x00ffffff;
|
|
|
|
/* Store L2TP info in the skb */
|
|
L2TP_SKB_CB(skb)->ns = ns;
|
|
L2TP_SKB_CB(skb)->has_seq = 1;
|
|
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: recv data ns=%u, session nr=%u\n",
|
|
session->name, ns, session->nr);
|
|
}
|
|
}
|
|
|
|
/* Advance past L2-specific header, if present */
|
|
ptr += session->l2specific_len;
|
|
|
|
if (L2TP_SKB_CB(skb)->has_seq) {
|
|
/* Received a packet with sequence numbers. If we're the LNS,
|
|
* check if we sre sending sequence numbers and if not,
|
|
* configure it so.
|
|
*/
|
|
if ((!session->lns_mode) && (!session->send_seq)) {
|
|
l2tp_info(session, L2TP_MSG_SEQ,
|
|
"%s: requested to enable seq numbers by LNS\n",
|
|
session->name);
|
|
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) {
|
|
l2tp_warn(session, L2TP_MSG_SEQ,
|
|
"%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)) {
|
|
l2tp_info(session, L2TP_MSG_SEQ,
|
|
"%s: requested to disable seq numbers by LNS\n",
|
|
session->name);
|
|
session->send_seq = 0;
|
|
l2tp_session_set_header_len(session, tunnel->version);
|
|
} else if (session->send_seq) {
|
|
l2tp_warn(session, L2TP_MSG_SEQ,
|
|
"%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 handled differently for L2TPv2 and
|
|
* L2TPv3. For L2TPv2, there is an optional 16-bit value in
|
|
* the header. For L2TPv3, the offset is negotiated using AVPs
|
|
* in the session setup control protocol.
|
|
*/
|
|
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;
|
|
}
|
|
} else
|
|
ptr += session->offset;
|
|
|
|
offset = ptr - optr;
|
|
if (!pskb_may_pull(skb, offset))
|
|
goto discard;
|
|
|
|
__skb_pull(skb, offset);
|
|
|
|
/* If caller wants to process the payload before we queue the
|
|
* packet, do so now.
|
|
*/
|
|
if (payload_hook)
|
|
if ((*payload_hook)(skb))
|
|
goto discard;
|
|
|
|
/* 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);
|
|
|
|
l2tp_session_dec_refcount(session);
|
|
|
|
return;
|
|
|
|
discard:
|
|
atomic_long_inc(&session->stats.rx_errors);
|
|
kfree_skb(skb);
|
|
|
|
if (session->deref)
|
|
(*session->deref)(session);
|
|
|
|
l2tp_session_dec_refcount(session);
|
|
}
|
|
EXPORT_SYMBOL(l2tp_recv_common);
|
|
|
|
/* Drop skbs from the session's reorder_q
|
|
*/
|
|
int l2tp_session_queue_purge(struct l2tp_session *session)
|
|
{
|
|
struct sk_buff *skb = NULL;
|
|
BUG_ON(!session);
|
|
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
|
|
while ((skb = skb_dequeue(&session->reorder_q))) {
|
|
atomic_long_inc(&session->stats.rx_errors);
|
|
kfree_skb(skb);
|
|
if (session->deref)
|
|
(*session->deref)(session);
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
|
|
|
|
/* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
|
|
* here. The skb is not on a list when we get here.
|
|
* Returns 0 if the packet was a data packet and was successfully passed on.
|
|
* Returns 1 if the packet was not a good data packet and could not be
|
|
* forwarded. All such packets are passed up to userspace to deal with.
|
|
*/
|
|
static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
|
|
int (*payload_hook)(struct sk_buff *skb))
|
|
{
|
|
struct l2tp_session *session = NULL;
|
|
unsigned char *ptr, *optr;
|
|
u16 hdrflags;
|
|
u32 tunnel_id, session_id;
|
|
u16 version;
|
|
int length;
|
|
|
|
if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
|
|
goto discard_bad_csum;
|
|
|
|
/* UDP always verifies the packet length. */
|
|
__skb_pull(skb, sizeof(struct udphdr));
|
|
|
|
/* Short packet? */
|
|
if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
|
|
l2tp_info(tunnel, L2TP_MSG_DATA,
|
|
"%s: recv short packet (len=%d)\n",
|
|
tunnel->name, skb->len);
|
|
goto error;
|
|
}
|
|
|
|
/* Trace packet contents, if enabled */
|
|
if (tunnel->debug & L2TP_MSG_DATA) {
|
|
length = min(32u, skb->len);
|
|
if (!pskb_may_pull(skb, length))
|
|
goto error;
|
|
|
|
pr_debug("%s: recv\n", tunnel->name);
|
|
print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
|
|
}
|
|
|
|
/* Point to L2TP header */
|
|
optr = ptr = skb->data;
|
|
|
|
/* Get L2TP header flags */
|
|
hdrflags = ntohs(*(__be16 *) ptr);
|
|
|
|
/* Check protocol version */
|
|
version = hdrflags & L2TP_HDR_VER_MASK;
|
|
if (version != tunnel->version) {
|
|
l2tp_info(tunnel, L2TP_MSG_DATA,
|
|
"%s: recv protocol version mismatch: got %d expected %d\n",
|
|
tunnel->name, version, tunnel->version);
|
|
goto error;
|
|
}
|
|
|
|
/* Get length of L2TP packet */
|
|
length = skb->len;
|
|
|
|
/* If type is control packet, it is handled by userspace. */
|
|
if (hdrflags & L2TP_HDRFLAG_T) {
|
|
l2tp_dbg(tunnel, L2TP_MSG_DATA,
|
|
"%s: recv control packet, len=%d\n",
|
|
tunnel->name, length);
|
|
goto error;
|
|
}
|
|
|
|
/* Skip flags */
|
|
ptr += 2;
|
|
|
|
if (tunnel->version == L2TP_HDR_VER_2) {
|
|
/* 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;
|
|
} else {
|
|
ptr += 2; /* skip reserved bits */
|
|
tunnel_id = tunnel->tunnel_id;
|
|
session_id = ntohl(*(__be32 *) ptr);
|
|
ptr += 4;
|
|
}
|
|
|
|
/* Find the session context */
|
|
session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
|
|
if (!session || !session->recv_skb) {
|
|
/* Not found? Pass to userspace to deal with */
|
|
l2tp_info(tunnel, L2TP_MSG_DATA,
|
|
"%s: no session found (%u/%u). Passing up.\n",
|
|
tunnel->name, tunnel_id, session_id);
|
|
goto error;
|
|
}
|
|
|
|
l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook);
|
|
|
|
return 0;
|
|
|
|
discard_bad_csum:
|
|
LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
|
|
UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
|
|
atomic_long_inc(&tunnel->stats.rx_errors);
|
|
kfree_skb(skb);
|
|
|
|
return 0;
|
|
|
|
error:
|
|
/* Put UDP header back */
|
|
__skb_push(skb, sizeof(struct udphdr));
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* UDP encapsulation receive handler. See net/ipv4/udp.c.
|
|
* Return codes:
|
|
* 0 : success.
|
|
* <0: error
|
|
* >0: skb should be passed up to userspace as UDP.
|
|
*/
|
|
int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct l2tp_tunnel *tunnel;
|
|
|
|
tunnel = l2tp_sock_to_tunnel(sk);
|
|
if (tunnel == NULL)
|
|
goto pass_up;
|
|
|
|
l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
|
|
tunnel->name, skb->len);
|
|
|
|
if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
|
|
goto pass_up_put;
|
|
|
|
sock_put(sk);
|
|
return 0;
|
|
|
|
pass_up_put:
|
|
sock_put(sk);
|
|
pass_up:
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
|
|
|
|
/************************************************************************
|
|
* 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;
|
|
l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
|
|
session->name, session->ns);
|
|
}
|
|
|
|
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_len) {
|
|
if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
|
|
u32 l2h = 0;
|
|
if (session->send_seq) {
|
|
l2h = 0x40000000 | session->ns;
|
|
session->ns++;
|
|
session->ns &= 0xffffff;
|
|
l2tp_dbg(session, L2TP_MSG_SEQ,
|
|
"%s: updated ns to %u\n",
|
|
session->name, session->ns);
|
|
}
|
|
|
|
*((__be32 *) bufp) = htonl(l2h);
|
|
}
|
|
bufp += session->l2specific_len;
|
|
}
|
|
if (session->offset)
|
|
bufp += session->offset;
|
|
|
|
return bufp - optr;
|
|
}
|
|
|
|
static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
|
|
struct flowi *fl, size_t data_len)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
unsigned int len = skb->len;
|
|
int error;
|
|
|
|
/* Debug */
|
|
if (session->send_seq)
|
|
l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
|
|
session->name, data_len, session->ns - 1);
|
|
else
|
|
l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
|
|
session->name, data_len);
|
|
|
|
if (session->debug & L2TP_MSG_DATA) {
|
|
int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
|
|
unsigned char *datap = skb->data + uhlen;
|
|
|
|
pr_debug("%s: xmit\n", session->name);
|
|
print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
|
|
datap, min_t(size_t, 32, len - uhlen));
|
|
}
|
|
|
|
/* Queue the packet to IP for output */
|
|
skb->local_df = 1;
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (skb->sk->sk_family == PF_INET6 && !tunnel->v4mapped)
|
|
error = inet6_csk_xmit(skb, NULL);
|
|
else
|
|
#endif
|
|
error = ip_queue_xmit(skb, fl);
|
|
|
|
/* Update stats */
|
|
if (error >= 0) {
|
|
atomic_long_inc(&tunnel->stats.tx_packets);
|
|
atomic_long_add(len, &tunnel->stats.tx_bytes);
|
|
atomic_long_inc(&session->stats.tx_packets);
|
|
atomic_long_add(len, &session->stats.tx_bytes);
|
|
} else {
|
|
atomic_long_inc(&tunnel->stats.tx_errors);
|
|
atomic_long_inc(&session->stats.tx_errors);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Automatically called when the skb is freed.
|
|
*/
|
|
static void l2tp_sock_wfree(struct sk_buff *skb)
|
|
{
|
|
sock_put(skb->sk);
|
|
}
|
|
|
|
/* For data skbs that we transmit, we associate with the tunnel socket
|
|
* but don't do accounting.
|
|
*/
|
|
static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
|
|
{
|
|
sock_hold(sk);
|
|
skb->sk = sk;
|
|
skb->destructor = l2tp_sock_wfree;
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb,
|
|
int udp_len)
|
|
{
|
|
struct ipv6_pinfo *np = inet6_sk(sk);
|
|
struct udphdr *uh = udp_hdr(skb);
|
|
|
|
if (!skb_dst(skb) || !skb_dst(skb)->dev ||
|
|
!(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
|
|
__wsum csum = skb_checksum(skb, 0, udp_len, 0);
|
|
skb->ip_summed = CHECKSUM_UNNECESSARY;
|
|
uh->check = csum_ipv6_magic(&np->saddr, &sk->sk_v6_daddr, udp_len,
|
|
IPPROTO_UDP, csum);
|
|
if (uh->check == 0)
|
|
uh->check = CSUM_MANGLED_0;
|
|
} else {
|
|
skb->ip_summed = CHECKSUM_PARTIAL;
|
|
skb->csum_start = skb_transport_header(skb) - skb->head;
|
|
skb->csum_offset = offsetof(struct udphdr, check);
|
|
uh->check = ~csum_ipv6_magic(&np->saddr, &sk->sk_v6_daddr,
|
|
udp_len, IPPROTO_UDP, 0);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* 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, int hdr_len)
|
|
{
|
|
int data_len = skb->len;
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
struct sock *sk = tunnel->sock;
|
|
struct flowi *fl;
|
|
struct udphdr *uh;
|
|
struct inet_sock *inet;
|
|
__wsum csum;
|
|
int headroom;
|
|
int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
|
|
int udp_len;
|
|
int ret = NET_XMIT_SUCCESS;
|
|
|
|
/* 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.
|
|
*/
|
|
headroom = NET_SKB_PAD + sizeof(struct iphdr) +
|
|
uhlen + hdr_len;
|
|
if (skb_cow_head(skb, headroom)) {
|
|
kfree_skb(skb);
|
|
return NET_XMIT_DROP;
|
|
}
|
|
|
|
skb_orphan(skb);
|
|
/* Setup L2TP header */
|
|
session->build_header(session, __skb_push(skb, 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(skb);
|
|
|
|
bh_lock_sock(sk);
|
|
if (sock_owned_by_user(sk)) {
|
|
kfree_skb(skb);
|
|
ret = NET_XMIT_DROP;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Get routing info from the tunnel socket */
|
|
skb_dst_drop(skb);
|
|
skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
|
|
|
|
inet = inet_sk(sk);
|
|
fl = &inet->cork.fl;
|
|
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 + hdr_len + data_len;
|
|
uh->len = htons(udp_len);
|
|
uh->check = 0;
|
|
|
|
/* Calculate UDP checksum if configured to do so */
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
|
|
l2tp_xmit_ipv6_csum(sk, skb, udp_len);
|
|
else
|
|
#endif
|
|
if (sk->sk_no_check == UDP_CSUM_NOXMIT)
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
|
|
(!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
|
|
skb->ip_summed = CHECKSUM_COMPLETE;
|
|
csum = skb_checksum(skb, 0, udp_len, 0);
|
|
uh->check = csum_tcpudp_magic(inet->inet_saddr,
|
|
inet->inet_daddr,
|
|
udp_len, IPPROTO_UDP, csum);
|
|
if (uh->check == 0)
|
|
uh->check = CSUM_MANGLED_0;
|
|
} else {
|
|
skb->ip_summed = CHECKSUM_PARTIAL;
|
|
skb->csum_start = skb_transport_header(skb) - skb->head;
|
|
skb->csum_offset = offsetof(struct udphdr, check);
|
|
uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
|
|
inet->inet_daddr,
|
|
udp_len, IPPROTO_UDP, 0);
|
|
}
|
|
break;
|
|
|
|
case L2TP_ENCAPTYPE_IP:
|
|
break;
|
|
}
|
|
|
|
l2tp_skb_set_owner_w(skb, sk);
|
|
|
|
l2tp_xmit_core(session, skb, fl, data_len);
|
|
out_unlock:
|
|
bh_unlock_sock(sk);
|
|
|
|
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_tunnel(sk);
|
|
struct l2tp_net *pn;
|
|
|
|
if (tunnel == NULL)
|
|
goto end;
|
|
|
|
l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
|
|
|
|
|
|
/* Disable udp encapsulation */
|
|
switch (tunnel->encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
/* No longer an encapsulation socket. See net/ipv4/udp.c */
|
|
(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 */
|
|
sk->sk_destruct = tunnel->old_sk_destruct;
|
|
sk->sk_user_data = NULL;
|
|
tunnel->sock = NULL;
|
|
|
|
/* Remove the tunnel struct from the tunnel list */
|
|
pn = l2tp_pernet(tunnel->l2tp_net);
|
|
spin_lock_bh(&pn->l2tp_tunnel_list_lock);
|
|
list_del_rcu(&tunnel->list);
|
|
spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
|
atomic_dec(&l2tp_tunnel_count);
|
|
|
|
l2tp_tunnel_closeall(tunnel);
|
|
l2tp_tunnel_dec_refcount(tunnel);
|
|
|
|
/* Call the original destructor */
|
|
if (sk->sk_destruct)
|
|
(*sk->sk_destruct)(sk);
|
|
end:
|
|
return;
|
|
}
|
|
|
|
/* When the tunnel is closed, all the attached sessions need to go too.
|
|
*/
|
|
void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
|
|
{
|
|
int hash;
|
|
struct hlist_node *walk;
|
|
struct hlist_node *tmp;
|
|
struct l2tp_session *session;
|
|
|
|
BUG_ON(tunnel == NULL);
|
|
|
|
l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
|
|
tunnel->name);
|
|
|
|
write_lock_bh(&tunnel->hlist_lock);
|
|
for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
|
|
again:
|
|
hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
|
|
session = hlist_entry(walk, struct l2tp_session, hlist);
|
|
|
|
l2tp_info(session, L2TP_MSG_CONTROL,
|
|
"%s: closing session\n", session->name);
|
|
|
|
hlist_del_init(&session->hlist);
|
|
|
|
if (session->ref != NULL)
|
|
(*session->ref)(session);
|
|
|
|
write_unlock_bh(&tunnel->hlist_lock);
|
|
|
|
__l2tp_session_unhash(session);
|
|
l2tp_session_queue_purge(session);
|
|
|
|
if (session->session_close != NULL)
|
|
(*session->session_close)(session);
|
|
|
|
if (session->deref != NULL)
|
|
(*session->deref)(session);
|
|
|
|
l2tp_session_dec_refcount(session);
|
|
|
|
write_lock_bh(&tunnel->hlist_lock);
|
|
|
|
/* Now restart from the beginning of this hash
|
|
* chain. We always remove a session from the
|
|
* list so we are guaranteed to make forward
|
|
* progress.
|
|
*/
|
|
goto again;
|
|
}
|
|
}
|
|
write_unlock_bh(&tunnel->hlist_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
|
|
|
|
/* Tunnel socket destroy hook for UDP encapsulation */
|
|
static void l2tp_udp_encap_destroy(struct sock *sk)
|
|
{
|
|
struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
|
|
if (tunnel) {
|
|
l2tp_tunnel_closeall(tunnel);
|
|
sock_put(sk);
|
|
}
|
|
}
|
|
|
|
/* Really kill the tunnel.
|
|
* Come here only when all sessions have been cleared from the tunnel.
|
|
*/
|
|
static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
|
|
{
|
|
BUG_ON(atomic_read(&tunnel->ref_count) != 0);
|
|
BUG_ON(tunnel->sock != NULL);
|
|
l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
|
|
kfree_rcu(tunnel, rcu);
|
|
}
|
|
|
|
/* Workqueue tunnel deletion function */
|
|
static void l2tp_tunnel_del_work(struct work_struct *work)
|
|
{
|
|
struct l2tp_tunnel *tunnel = NULL;
|
|
struct socket *sock = NULL;
|
|
struct sock *sk = NULL;
|
|
|
|
tunnel = container_of(work, struct l2tp_tunnel, del_work);
|
|
sk = l2tp_tunnel_sock_lookup(tunnel);
|
|
if (!sk)
|
|
return;
|
|
|
|
sock = sk->sk_socket;
|
|
|
|
/* If the tunnel socket was created by userspace, then go through the
|
|
* inet layer to shut the socket down, and let userspace close it.
|
|
* Otherwise, if we created the socket directly within the kernel, use
|
|
* the sk API to release it here.
|
|
* In either case the tunnel resources are freed in the socket
|
|
* destructor when the tunnel socket goes away.
|
|
*/
|
|
if (tunnel->fd >= 0) {
|
|
if (sock)
|
|
inet_shutdown(sock, 2);
|
|
} else {
|
|
if (sock)
|
|
kernel_sock_shutdown(sock, SHUT_RDWR);
|
|
sk_release_kernel(sk);
|
|
}
|
|
|
|
l2tp_tunnel_sock_put(sk);
|
|
}
|
|
|
|
/* 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 sockaddr_in udp_addr = {0};
|
|
struct sockaddr_l2tpip ip_addr = {0};
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
struct sockaddr_in6 udp6_addr = {0};
|
|
struct sockaddr_l2tpip6 ip6_addr = {0};
|
|
#endif
|
|
|
|
switch (cfg->encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (cfg->local_ip6 && cfg->peer_ip6) {
|
|
err = sock_create_kern(AF_INET6, SOCK_DGRAM, 0, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
sk_change_net(sock->sk, net);
|
|
|
|
udp6_addr.sin6_family = AF_INET6;
|
|
memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
|
|
sizeof(udp6_addr.sin6_addr));
|
|
udp6_addr.sin6_port = htons(cfg->local_udp_port);
|
|
err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
|
|
sizeof(udp6_addr));
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
udp6_addr.sin6_family = AF_INET6;
|
|
memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
|
|
sizeof(udp6_addr.sin6_addr));
|
|
udp6_addr.sin6_port = htons(cfg->peer_udp_port);
|
|
err = kernel_connect(sock,
|
|
(struct sockaddr *) &udp6_addr,
|
|
sizeof(udp6_addr), 0);
|
|
if (err < 0)
|
|
goto out;
|
|
} else
|
|
#endif
|
|
{
|
|
err = sock_create_kern(AF_INET, SOCK_DGRAM, 0, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
sk_change_net(sock->sk, net);
|
|
|
|
udp_addr.sin_family = AF_INET;
|
|
udp_addr.sin_addr = cfg->local_ip;
|
|
udp_addr.sin_port = htons(cfg->local_udp_port);
|
|
err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
|
|
sizeof(udp_addr));
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
udp_addr.sin_family = AF_INET;
|
|
udp_addr.sin_addr = cfg->peer_ip;
|
|
udp_addr.sin_port = htons(cfg->peer_udp_port);
|
|
err = kernel_connect(sock,
|
|
(struct sockaddr *) &udp_addr,
|
|
sizeof(udp_addr), 0);
|
|
if (err < 0)
|
|
goto out;
|
|
}
|
|
|
|
if (!cfg->use_udp_checksums)
|
|
sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
|
|
|
|
break;
|
|
|
|
case L2TP_ENCAPTYPE_IP:
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (cfg->local_ip6 && cfg->peer_ip6) {
|
|
err = sock_create_kern(AF_INET6, SOCK_DGRAM,
|
|
IPPROTO_L2TP, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
sk_change_net(sock->sk, net);
|
|
|
|
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
|
|
{
|
|
err = sock_create_kern(AF_INET, SOCK_DGRAM,
|
|
IPPROTO_L2TP, &sock);
|
|
if (err < 0)
|
|
goto out;
|
|
|
|
sk_change_net(sock->sk, net);
|
|
|
|
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);
|
|
sk_release_kernel(sock->sk);
|
|
*sockp = NULL;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static struct lock_class_key l2tp_socket_class;
|
|
|
|
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)
|
|
{
|
|
struct l2tp_tunnel *tunnel = NULL;
|
|
int err;
|
|
struct socket *sock = NULL;
|
|
struct sock *sk = NULL;
|
|
struct l2tp_net *pn;
|
|
enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
|
|
|
|
/* Get the tunnel socket from the fd, which was opened by
|
|
* the userspace L2TP daemon. If not specified, create a
|
|
* kernel socket.
|
|
*/
|
|
if (fd < 0) {
|
|
err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
|
|
cfg, &sock);
|
|
if (err < 0)
|
|
goto err;
|
|
} else {
|
|
sock = sockfd_lookup(fd, &err);
|
|
if (!sock) {
|
|
pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
|
|
tunnel_id, fd, err);
|
|
err = -EBADF;
|
|
goto err;
|
|
}
|
|
|
|
/* Reject namespace mismatches */
|
|
if (!net_eq(sock_net(sock->sk), net)) {
|
|
pr_err("tunl %u: netns mismatch\n", tunnel_id);
|
|
err = -EINVAL;
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
sk = sock->sk;
|
|
|
|
if (cfg != NULL)
|
|
encap = cfg->encap;
|
|
|
|
/* Quick sanity checks */
|
|
switch (encap) {
|
|
case L2TP_ENCAPTYPE_UDP:
|
|
err = -EPROTONOSUPPORT;
|
|
if (sk->sk_protocol != IPPROTO_UDP) {
|
|
pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
|
|
tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
|
|
goto err;
|
|
}
|
|
break;
|
|
case L2TP_ENCAPTYPE_IP:
|
|
err = -EPROTONOSUPPORT;
|
|
if (sk->sk_protocol != IPPROTO_L2TP) {
|
|
pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
|
|
tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
|
|
goto err;
|
|
}
|
|
break;
|
|
}
|
|
|
|
/* Check if this socket has already been prepped */
|
|
tunnel = l2tp_tunnel(sk);
|
|
if (tunnel != NULL) {
|
|
/* This socket has already been prepped */
|
|
err = -EBUSY;
|
|
goto err;
|
|
}
|
|
|
|
tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
|
|
if (tunnel == NULL) {
|
|
err = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
tunnel->version = version;
|
|
tunnel->tunnel_id = tunnel_id;
|
|
tunnel->peer_tunnel_id = peer_tunnel_id;
|
|
tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS;
|
|
|
|
tunnel->magic = L2TP_TUNNEL_MAGIC;
|
|
sprintf(&tunnel->name[0], "tunl %u", tunnel_id);
|
|
rwlock_init(&tunnel->hlist_lock);
|
|
|
|
/* The net we belong to */
|
|
tunnel->l2tp_net = net;
|
|
pn = l2tp_pernet(net);
|
|
|
|
if (cfg != NULL)
|
|
tunnel->debug = cfg->debug;
|
|
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (sk->sk_family == PF_INET6) {
|
|
struct ipv6_pinfo *np = inet6_sk(sk);
|
|
|
|
if (ipv6_addr_v4mapped(&np->saddr) &&
|
|
ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
|
|
tunnel->v4mapped = true;
|
|
inet->inet_saddr = np->saddr.s6_addr32[3];
|
|
inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3];
|
|
inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3];
|
|
} else {
|
|
tunnel->v4mapped = false;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
|
|
tunnel->encap = encap;
|
|
if (encap == L2TP_ENCAPTYPE_UDP) {
|
|
/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
|
|
udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
|
|
udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
|
|
udp_sk(sk)->encap_destroy = l2tp_udp_encap_destroy;
|
|
#if IS_ENABLED(CONFIG_IPV6)
|
|
if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
|
|
udpv6_encap_enable();
|
|
else
|
|
#endif
|
|
udp_encap_enable();
|
|
}
|
|
|
|
sk->sk_user_data = tunnel;
|
|
|
|
/* Hook on the tunnel socket destructor so that we can cleanup
|
|
* if the tunnel socket goes away.
|
|
*/
|
|
tunnel->old_sk_destruct = sk->sk_destruct;
|
|
sk->sk_destruct = &l2tp_tunnel_destruct;
|
|
tunnel->sock = sk;
|
|
tunnel->fd = fd;
|
|
lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
|
|
|
|
sk->sk_allocation = GFP_ATOMIC;
|
|
|
|
/* Init delete workqueue struct */
|
|
INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
|
|
|
|
/* Add tunnel to our list */
|
|
INIT_LIST_HEAD(&tunnel->list);
|
|
atomic_inc(&l2tp_tunnel_count);
|
|
|
|
/* Bump the reference count. The tunnel context is deleted
|
|
* only when this drops to zero. Must be done before list insertion
|
|
*/
|
|
l2tp_tunnel_inc_refcount(tunnel);
|
|
spin_lock_bh(&pn->l2tp_tunnel_list_lock);
|
|
list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
|
|
spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
|
|
|
|
err = 0;
|
|
err:
|
|
if (tunnelp)
|
|
*tunnelp = tunnel;
|
|
|
|
/* If tunnel's socket was created by the kernel, it doesn't
|
|
* have a file.
|
|
*/
|
|
if (sock && sock->file)
|
|
sockfd_put(sock);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
|
|
|
|
/* This function is used by the netlink TUNNEL_DELETE command.
|
|
*/
|
|
int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
|
|
{
|
|
l2tp_tunnel_closeall(tunnel);
|
|
return (false == queue_work(l2tp_wq, &tunnel->del_work));
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
|
|
|
|
/* Really kill the session.
|
|
*/
|
|
void l2tp_session_free(struct l2tp_session *session)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
|
|
BUG_ON(atomic_read(&session->ref_count) != 0);
|
|
|
|
if (tunnel) {
|
|
BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
|
|
if (session->session_id != 0)
|
|
atomic_dec(&l2tp_session_count);
|
|
sock_put(tunnel->sock);
|
|
session->tunnel = NULL;
|
|
l2tp_tunnel_dec_refcount(tunnel);
|
|
}
|
|
|
|
kfree(session);
|
|
|
|
return;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_free);
|
|
|
|
/* Remove an l2tp session from l2tp_core's hash lists.
|
|
* Provides a tidyup interface for pseudowire code which can't just route all
|
|
* shutdown via. l2tp_session_delete and a pseudowire-specific session_close
|
|
* callback.
|
|
*/
|
|
void __l2tp_session_unhash(struct l2tp_session *session)
|
|
{
|
|
struct l2tp_tunnel *tunnel = session->tunnel;
|
|
|
|
/* Remove the session from core hashes */
|
|
if (tunnel) {
|
|
/* Remove from the per-tunnel hash */
|
|
write_lock_bh(&tunnel->hlist_lock);
|
|
hlist_del_init(&session->hlist);
|
|
write_unlock_bh(&tunnel->hlist_lock);
|
|
|
|
/* For L2TPv3 we have a per-net hash: remove from there, too */
|
|
if (tunnel->version != L2TP_HDR_VER_2) {
|
|
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
|
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
|
hlist_del_init_rcu(&session->global_hlist);
|
|
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
|
synchronize_rcu();
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
|
|
|
|
/* This function is used by the netlink SESSION_DELETE command and by
|
|
pseudowire modules.
|
|
*/
|
|
int l2tp_session_delete(struct l2tp_session *session)
|
|
{
|
|
if (session->ref)
|
|
(*session->ref)(session);
|
|
__l2tp_session_unhash(session);
|
|
l2tp_session_queue_purge(session);
|
|
if (session->session_close != NULL)
|
|
(*session->session_close)(session);
|
|
if (session->deref)
|
|
(*session->deref)(session);
|
|
l2tp_session_dec_refcount(session);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(l2tp_session_delete);
|
|
|
|
/* We come here whenever a session's send_seq, cookie_len or
|
|
* l2specific_len parameters are set.
|
|
*/
|
|
static 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->l2specific_len + session->offset;
|
|
if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
|
|
session->hdr_len += 4;
|
|
}
|
|
|
|
}
|
|
|
|
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(struct l2tp_session) + priv_size, GFP_KERNEL);
|
|
if (session != NULL) {
|
|
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);
|
|
|
|
INIT_HLIST_NODE(&session->hlist);
|
|
INIT_HLIST_NODE(&session->global_hlist);
|
|
|
|
/* Inherit debug options from tunnel */
|
|
session->debug = tunnel->debug;
|
|
|
|
if (cfg) {
|
|
session->pwtype = cfg->pw_type;
|
|
session->debug = cfg->debug;
|
|
session->mtu = cfg->mtu;
|
|
session->mru = cfg->mru;
|
|
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->offset = cfg->offset;
|
|
session->l2specific_type = cfg->l2specific_type;
|
|
session->l2specific_len = cfg->l2specific_len;
|
|
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);
|
|
}
|
|
|
|
if (tunnel->version == L2TP_HDR_VER_2)
|
|
session->build_header = l2tp_build_l2tpv2_header;
|
|
else
|
|
session->build_header = l2tp_build_l2tpv3_header;
|
|
|
|
l2tp_session_set_header_len(session, tunnel->version);
|
|
|
|
/* Bump the reference count. The session context is deleted
|
|
* only when this drops to zero.
|
|
*/
|
|
l2tp_session_inc_refcount(session);
|
|
l2tp_tunnel_inc_refcount(tunnel);
|
|
|
|
/* Ensure tunnel socket isn't deleted */
|
|
sock_hold(tunnel->sock);
|
|
|
|
/* Add session to the tunnel's hash list */
|
|
write_lock_bh(&tunnel->hlist_lock);
|
|
hlist_add_head(&session->hlist,
|
|
l2tp_session_id_hash(tunnel, session_id));
|
|
write_unlock_bh(&tunnel->hlist_lock);
|
|
|
|
/* And to the global session list if L2TPv3 */
|
|
if (tunnel->version != L2TP_HDR_VER_2) {
|
|
struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
|
|
|
|
spin_lock_bh(&pn->l2tp_session_hlist_lock);
|
|
hlist_add_head_rcu(&session->global_hlist,
|
|
l2tp_session_id_hash_2(pn, session_id));
|
|
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
|
|
}
|
|
|
|
/* Ignore management session in session count value */
|
|
if (session->session_id != 0)
|
|
atomic_inc(&l2tp_session_count);
|
|
}
|
|
|
|
return session;
|
|
}
|
|
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);
|
|
int hash;
|
|
|
|
INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
|
|
spin_lock_init(&pn->l2tp_tunnel_list_lock);
|
|
|
|
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
|
|
INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
|
|
|
|
spin_lock_init(&pn->l2tp_session_hlist_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;
|
|
|
|
rcu_read_lock_bh();
|
|
list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
|
|
(void)l2tp_tunnel_delete(tunnel);
|
|
}
|
|
rcu_read_unlock_bh();
|
|
}
|
|
|
|
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_NON_REENTRANT | WQ_UNBOUND, 0);
|
|
if (!l2tp_wq) {
|
|
pr_err("alloc_workqueue failed\n");
|
|
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);
|
|
|