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1719 lines
45 KiB
1719 lines
45 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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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 <[email protected]> |
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* James Chapman ([email protected]) |
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* Contributors: |
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* Michal Ostrowski <[email protected]> |
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* Arnaldo Carvalho de Melo <[email protected]> |
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* David S. Miller ([email protected]) |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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|
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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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|
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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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|
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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/udp_tunnel.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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|
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#include <asm/byteorder.h> |
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#include <linux/atomic.h> |
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|
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#include "l2tp_core.h" |
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#include "trace.h" |
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|
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#define CREATE_TRACE_POINTS |
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#include "trace.h" |
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|
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#define L2TP_DRV_VERSION "V2.0" |
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|
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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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|
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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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|
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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_MAX 14 |
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|
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/* Default trace flags */ |
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#define L2TP_DEFAULT_DEBUG_FLAGS 0 |
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|
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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 struct workqueue_struct *l2tp_wq; |
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|
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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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/* Lock for write access to 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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/* Lock for write access to l2tp_session_hlist */ |
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spinlock_t l2tp_session_hlist_lock; |
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}; |
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|
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#if IS_ENABLED(CONFIG_IPV6) |
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static bool l2tp_sk_is_v6(struct sock *sk) |
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{ |
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return sk->sk_family == PF_INET6 && |
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!ipv6_addr_v4mapped(&sk->sk_v6_daddr); |
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} |
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#endif |
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|
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static inline struct l2tp_net *l2tp_pernet(const struct net *net) |
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{ |
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return net_generic(net, l2tp_net_id); |
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} |
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|
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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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|
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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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static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel) |
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{ |
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trace_free_tunnel(tunnel); |
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sock_put(tunnel->sock); |
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/* the tunnel is freed in the socket destructor */ |
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} |
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|
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static void l2tp_session_free(struct l2tp_session *session) |
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{ |
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trace_free_session(session); |
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if (session->tunnel) |
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l2tp_tunnel_dec_refcount(session->tunnel); |
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kfree(session); |
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} |
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struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk) |
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{ |
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struct l2tp_tunnel *tunnel = sk->sk_user_data; |
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|
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if (tunnel) |
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if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC)) |
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return NULL; |
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|
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return tunnel; |
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} |
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EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel); |
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|
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void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) |
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{ |
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refcount_inc(&tunnel->ref_count); |
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} |
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EXPORT_SYMBOL_GPL(l2tp_tunnel_inc_refcount); |
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|
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void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) |
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{ |
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if (refcount_dec_and_test(&tunnel->ref_count)) |
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l2tp_tunnel_free(tunnel); |
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} |
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EXPORT_SYMBOL_GPL(l2tp_tunnel_dec_refcount); |
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|
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void l2tp_session_inc_refcount(struct l2tp_session *session) |
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{ |
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refcount_inc(&session->ref_count); |
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} |
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EXPORT_SYMBOL_GPL(l2tp_session_inc_refcount); |
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|
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void l2tp_session_dec_refcount(struct l2tp_session *session) |
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{ |
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if (refcount_dec_and_test(&session->ref_count)) |
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l2tp_session_free(session); |
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} |
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EXPORT_SYMBOL_GPL(l2tp_session_dec_refcount); |
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|
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/* Lookup a tunnel. A new reference is held on the returned tunnel. */ |
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struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id) |
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{ |
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const struct l2tp_net *pn = l2tp_pernet(net); |
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struct l2tp_tunnel *tunnel; |
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|
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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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refcount_inc_not_zero(&tunnel->ref_count)) { |
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rcu_read_unlock_bh(); |
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|
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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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|
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return NULL; |
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} |
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EXPORT_SYMBOL_GPL(l2tp_tunnel_get); |
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|
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struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth) |
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{ |
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const 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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|
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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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refcount_inc_not_zero(&tunnel->ref_count)) { |
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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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|
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return NULL; |
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} |
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EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth); |
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struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel, |
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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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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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l2tp_session_inc_refcount(session); |
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read_unlock_bh(&tunnel->hlist_lock); |
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return session; |
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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_tunnel_get_session); |
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struct l2tp_session *l2tp_session_get(const struct net *net, 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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session_list = l2tp_session_id_hash_2(l2tp_pernet(net), session_id); |
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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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l2tp_session_inc_refcount(session); |
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rcu_read_unlock_bh(); |
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return session; |
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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_get); |
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struct l2tp_session *l2tp_session_get_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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l2tp_session_inc_refcount(session); |
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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_get_nth); |
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|
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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_get_by_ifname(const struct net *net, |
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const 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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l2tp_session_inc_refcount(session); |
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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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|
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return NULL; |
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} |
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EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname); |
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|
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int l2tp_session_register(struct l2tp_session *session, |
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struct l2tp_tunnel *tunnel) |
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{ |
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struct l2tp_session *session_walk; |
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struct hlist_head *g_head; |
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struct hlist_head *head; |
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struct l2tp_net *pn; |
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int err; |
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|
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head = l2tp_session_id_hash(tunnel, session->session_id); |
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|
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write_lock_bh(&tunnel->hlist_lock); |
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if (!tunnel->acpt_newsess) { |
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err = -ENODEV; |
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goto err_tlock; |
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} |
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|
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hlist_for_each_entry(session_walk, head, hlist) |
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if (session_walk->session_id == session->session_id) { |
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err = -EEXIST; |
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goto err_tlock; |
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} |
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|
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if (tunnel->version == L2TP_HDR_VER_3) { |
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pn = l2tp_pernet(tunnel->l2tp_net); |
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g_head = l2tp_session_id_hash_2(pn, session->session_id); |
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|
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spin_lock_bh(&pn->l2tp_session_hlist_lock); |
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|
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/* IP encap expects session IDs to be globally unique, while |
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* UDP encap doesn't. |
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*/ |
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hlist_for_each_entry(session_walk, g_head, global_hlist) |
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if (session_walk->session_id == session->session_id && |
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(session_walk->tunnel->encap == L2TP_ENCAPTYPE_IP || |
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tunnel->encap == L2TP_ENCAPTYPE_IP)) { |
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err = -EEXIST; |
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goto err_tlock_pnlock; |
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} |
|
|
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l2tp_tunnel_inc_refcount(tunnel); |
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hlist_add_head_rcu(&session->global_hlist, g_head); |
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|
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spin_unlock_bh(&pn->l2tp_session_hlist_lock); |
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} else { |
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l2tp_tunnel_inc_refcount(tunnel); |
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} |
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hlist_add_head(&session->hlist, head); |
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write_unlock_bh(&tunnel->hlist_lock); |
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|
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trace_register_session(session); |
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|
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return 0; |
|
|
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err_tlock_pnlock: |
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spin_unlock_bh(&pn->l2tp_session_hlist_lock); |
|
err_tlock: |
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write_unlock_bh(&tunnel->hlist_lock); |
|
|
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return err; |
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} |
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EXPORT_SYMBOL_GPL(l2tp_session_register); |
|
|
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/***************************************************************************** |
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* Receive data handling |
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*****************************************************************************/ |
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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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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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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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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); |
|
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) |
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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); |
|
} |
|
|
|
/* 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) |
|
{ |
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struct sk_buff *skb; |
|
struct sk_buff *tmp; |
|
|
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/* 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) |
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nws = nr - session->nr; |
|
else |
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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); |
|
} |
|
} |
|
|
|
/* 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) |
|
{ |
|
struct l2tp_session *session = NULL; |
|
unsigned char *ptr, *optr; |
|
u16 hdrflags; |
|
u32 tunnel_id, session_id; |
|
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)) { |
|
pr_debug_ratelimited("%s: recv short packet (len=%d)\n", |
|
tunnel->name, skb->len); |
|
goto invalid; |
|
} |
|
|
|
/* Point to L2TP header */ |
|
optr = skb->data; |
|
ptr = skb->data; |
|
|
|
/* Get L2TP header flags */ |
|
hdrflags = ntohs(*(__be16 *)ptr); |
|
|
|
/* Check protocol version */ |
|
version = hdrflags & L2TP_HDR_VER_MASK; |
|
if (version != tunnel->version) { |
|
pr_debug_ratelimited("%s: recv protocol version mismatch: got %d expected %d\n", |
|
tunnel->name, version, tunnel->version); |
|
goto invalid; |
|
} |
|
|
|
/* 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 (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_tunnel_get_session(tunnel, session_id); |
|
if (!session || !session->recv_skb) { |
|
if (session) |
|
l2tp_session_dec_refcount(session); |
|
|
|
/* Not found? Pass to userspace to deal with */ |
|
pr_debug_ratelimited("%s: no session found (%u/%u). Passing up.\n", |
|
tunnel->name, tunnel_id, session_id); |
|
goto pass; |
|
} |
|
|
|
if (tunnel->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; |
|
} |
|
|
|
/* 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; |
|
|
|
/* Note that this is called from the encap_rcv hook inside an |
|
* RCU-protected region, but without the socket being locked. |
|
* Hence we use rcu_dereference_sk_user_data to access the |
|
* tunnel data structure rather the usual l2tp_sk_to_tunnel |
|
* accessor function. |
|
*/ |
|
tunnel = rcu_dereference_sk_user_data(sk); |
|
if (!tunnel) |
|
goto pass_up; |
|
if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC)) |
|
goto pass_up; |
|
|
|
if (l2tp_udp_recv_core(tunnel, skb)) |
|
goto pass_up; |
|
|
|
return 0; |
|
|
|
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; |
|
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); |
|
|
|
bh_lock_sock(sk); |
|
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: |
|
bh_unlock_sock(sk); |
|
|
|
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 */ |
|
(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; |
|
|
|
/* 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 hash lists. */ |
|
static 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(); |
|
} |
|
} |
|
} |
|
|
|
/* When the tunnel is closed, all the attached sessions need to go too. |
|
*/ |
|
static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) |
|
{ |
|
int hash; |
|
struct hlist_node *walk; |
|
struct hlist_node *tmp; |
|
struct l2tp_session *session; |
|
|
|
write_lock_bh(&tunnel->hlist_lock); |
|
tunnel->acpt_newsess = false; |
|
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); |
|
hlist_del_init(&session->hlist); |
|
|
|
write_unlock_bh(&tunnel->hlist_lock); |
|
l2tp_session_delete(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); |
|
} |
|
|
|
/* 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); |
|
} |
|
|
|
/* 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; |
|
struct l2tp_net *pn; |
|
|
|
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); |
|
} |
|
} |
|
|
|
/* 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); |
|
|
|
/* 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; |
|
} |
|
|
|
static struct lock_class_key l2tp_socket_class; |
|
|
|
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); |
|
rwlock_init(&tunnel->hlist_lock); |
|
tunnel->acpt_newsess = true; |
|
|
|
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); |
|
|
|
INIT_LIST_HEAD(&tunnel->list); |
|
|
|
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_tunnel *tunnel_walk; |
|
struct l2tp_net *pn; |
|
struct socket *sock; |
|
struct sock *sk; |
|
int 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; |
|
|
|
ret = l2tp_validate_socket(sock->sk, net, tunnel->encap); |
|
if (ret < 0) |
|
goto err_sock; |
|
} |
|
|
|
tunnel->l2tp_net = net; |
|
pn = l2tp_pernet(net); |
|
|
|
sk = sock->sk; |
|
sock_hold(sk); |
|
tunnel->sock = sk; |
|
|
|
spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
|
list_for_each_entry(tunnel_walk, &pn->l2tp_tunnel_list, list) { |
|
if (tunnel_walk->tunnel_id == tunnel->tunnel_id) { |
|
spin_unlock_bh(&pn->l2tp_tunnel_list_lock); |
|
sock_put(sk); |
|
ret = -EEXIST; |
|
goto err_sock; |
|
} |
|
} |
|
list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); |
|
spin_unlock_bh(&pn->l2tp_tunnel_list_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_destroy = l2tp_udp_encap_destroy, |
|
}; |
|
|
|
setup_udp_tunnel_sock(net, sock, &udp_cfg); |
|
} else { |
|
sk->sk_user_data = tunnel; |
|
} |
|
|
|
tunnel->old_sk_destruct = sk->sk_destruct; |
|
sk->sk_destruct = &l2tp_tunnel_destruct; |
|
lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, |
|
"l2tp_sock"); |
|
sk->sk_allocation = GFP_ATOMIC; |
|
|
|
trace_register_tunnel(tunnel); |
|
|
|
if (tunnel->fd >= 0) |
|
sockfd_put(sock); |
|
|
|
return 0; |
|
|
|
err_sock: |
|
if (tunnel->fd < 0) |
|
sock_release(sock); |
|
else |
|
sockfd_put(sock); |
|
err: |
|
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); |
|
|
|
INIT_HLIST_NODE(&session->hlist); |
|
INIT_HLIST_NODE(&session->global_hlist); |
|
|
|
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); |
|
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; |
|
int hash; |
|
|
|
rcu_read_lock_bh(); |
|
list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { |
|
l2tp_tunnel_delete(tunnel); |
|
} |
|
rcu_read_unlock_bh(); |
|
|
|
if (l2tp_wq) |
|
flush_workqueue(l2tp_wq); |
|
rcu_barrier(); |
|
|
|
for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) |
|
WARN_ON_ONCE(!hlist_empty(&pn->l2tp_session_hlist[hash])); |
|
} |
|
|
|
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 <[email protected]>"); |
|
MODULE_DESCRIPTION("L2TP core"); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_VERSION(L2TP_DRV_VERSION);
|
|
|