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5846c131c3
l2tp_tunnel_find_nth() is unsafe: no reference is held on the returned
tunnel, therefore it can be freed whenever the caller uses it.
This patch defines l2tp_tunnel_get_nth() which works similarly, but
also takes a reference on the returned tunnel. The caller then has to
drop it after it stops using the tunnel.
Convert netlink dumps to make them safe against concurrent tunnel
deletion.
Fixes: 309795f4be ("l2tp: Add netlink control API for L2TP")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
313 lines
9.3 KiB
C
313 lines
9.3 KiB
C
/*
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* L2TP internal definitions.
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*
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* Copyright (c) 2008,2009 Katalix Systems Ltd
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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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#include <linux/refcount.h>
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#ifndef _L2TP_CORE_H_
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#define _L2TP_CORE_H_
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/* Just some random numbers */
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#define L2TP_TUNNEL_MAGIC 0x42114DDA
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#define L2TP_SESSION_MAGIC 0x0C04EB7D
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/* Per tunnel, session hash table size */
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#define L2TP_HASH_BITS 4
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#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
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/* System-wide, session hash table size */
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#define L2TP_HASH_BITS_2 8
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#define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2)
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struct sk_buff;
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struct l2tp_stats {
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atomic_long_t tx_packets;
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atomic_long_t tx_bytes;
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atomic_long_t tx_errors;
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atomic_long_t rx_packets;
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atomic_long_t rx_bytes;
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atomic_long_t rx_seq_discards;
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atomic_long_t rx_oos_packets;
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atomic_long_t rx_errors;
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atomic_long_t rx_cookie_discards;
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};
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struct l2tp_tunnel;
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/* Describes a session. Contains information to determine incoming
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* packets and transmit outgoing ones.
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*/
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struct l2tp_session_cfg {
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enum l2tp_pwtype pw_type;
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unsigned int data_seq:2; /* data sequencing level
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* 0 => none, 1 => IP only,
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* 2 => all
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*/
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unsigned int recv_seq:1; /* expect receive packets with
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* sequence numbers? */
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unsigned int send_seq:1; /* send packets with sequence
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* numbers? */
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unsigned int lns_mode:1; /* behave as LNS? LAC enables
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* sequence numbers under
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* control of LNS. */
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int debug; /* bitmask of debug message
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* categories */
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u16 vlan_id; /* VLAN pseudowire only */
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u16 l2specific_type; /* Layer 2 specific type */
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u8 cookie[8]; /* optional cookie */
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int cookie_len; /* 0, 4 or 8 bytes */
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u8 peer_cookie[8]; /* peer's cookie */
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int peer_cookie_len; /* 0, 4 or 8 bytes */
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int reorder_timeout; /* configured reorder timeout
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* (in jiffies) */
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int mtu;
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int mru;
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char *ifname;
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};
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struct l2tp_session {
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int magic; /* should be
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* L2TP_SESSION_MAGIC */
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long dead;
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struct l2tp_tunnel *tunnel; /* back pointer to tunnel
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* context */
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u32 session_id;
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u32 peer_session_id;
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u8 cookie[8];
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int cookie_len;
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u8 peer_cookie[8];
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int peer_cookie_len;
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u16 l2specific_type;
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u16 hdr_len;
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u32 nr; /* session NR state (receive) */
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u32 ns; /* session NR state (send) */
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struct sk_buff_head reorder_q; /* receive reorder queue */
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u32 nr_max; /* max NR. Depends on tunnel */
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u32 nr_window_size; /* NR window size */
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u32 nr_oos; /* NR of last OOS packet */
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int nr_oos_count; /* For OOS recovery */
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int nr_oos_count_max;
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struct hlist_node hlist; /* Hash list node */
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refcount_t ref_count;
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char name[32]; /* for logging */
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char ifname[IFNAMSIZ];
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unsigned int data_seq:2; /* data sequencing level
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* 0 => none, 1 => IP only,
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* 2 => all
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*/
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unsigned int recv_seq:1; /* expect receive packets with
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* sequence numbers? */
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unsigned int send_seq:1; /* send packets with sequence
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* numbers? */
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unsigned int lns_mode:1; /* behave as LNS? LAC enables
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* sequence numbers under
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* control of LNS. */
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int debug; /* bitmask of debug message
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* categories */
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int reorder_timeout; /* configured reorder timeout
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* (in jiffies) */
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int reorder_skip; /* set if skip to next nr */
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int mtu;
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int mru;
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enum l2tp_pwtype pwtype;
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struct l2tp_stats stats;
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struct hlist_node global_hlist; /* Global hash list node */
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int (*build_header)(struct l2tp_session *session, void *buf);
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void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
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void (*session_close)(struct l2tp_session *session);
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#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
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void (*show)(struct seq_file *m, void *priv);
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#endif
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uint8_t priv[0]; /* private data */
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};
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/* Describes the tunnel. It contains info to track all the associated
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* sessions so incoming packets can be sorted out
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*/
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struct l2tp_tunnel_cfg {
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int debug; /* bitmask of debug message
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* categories */
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enum l2tp_encap_type encap;
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/* Used only for kernel-created sockets */
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struct in_addr local_ip;
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struct in_addr peer_ip;
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#if IS_ENABLED(CONFIG_IPV6)
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struct in6_addr *local_ip6;
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struct in6_addr *peer_ip6;
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#endif
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u16 local_udp_port;
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u16 peer_udp_port;
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unsigned int use_udp_checksums:1,
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udp6_zero_tx_checksums:1,
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udp6_zero_rx_checksums:1;
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};
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struct l2tp_tunnel {
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int magic; /* Should be L2TP_TUNNEL_MAGIC */
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unsigned long dead;
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struct rcu_head rcu;
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rwlock_t hlist_lock; /* protect session_hlist */
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bool acpt_newsess; /* Indicates whether this
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* tunnel accepts new sessions.
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* Protected by hlist_lock.
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*/
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struct hlist_head session_hlist[L2TP_HASH_SIZE];
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/* hashed list of sessions,
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* hashed by id */
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u32 tunnel_id;
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u32 peer_tunnel_id;
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int version; /* 2=>L2TPv2, 3=>L2TPv3 */
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char name[20]; /* for logging */
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int debug; /* bitmask of debug message
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* categories */
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enum l2tp_encap_type encap;
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struct l2tp_stats stats;
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struct list_head list; /* Keep a list of all tunnels */
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struct net *l2tp_net; /* the net we belong to */
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refcount_t ref_count;
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#ifdef CONFIG_DEBUG_FS
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void (*show)(struct seq_file *m, void *arg);
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#endif
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int (*recv_payload_hook)(struct sk_buff *skb);
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void (*old_sk_destruct)(struct sock *);
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struct sock *sock; /* Parent socket */
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int fd; /* Parent fd, if tunnel socket
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* was created by userspace */
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struct work_struct del_work;
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uint8_t priv[0]; /* private data */
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};
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struct l2tp_nl_cmd_ops {
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int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
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u32 session_id, u32 peer_session_id,
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struct l2tp_session_cfg *cfg);
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int (*session_delete)(struct l2tp_session *session);
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};
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static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel)
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{
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return &tunnel->priv[0];
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}
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static inline void *l2tp_session_priv(struct l2tp_session *session)
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{
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return &session->priv[0];
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}
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struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
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struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
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void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
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struct l2tp_session *l2tp_session_get(const struct net *net,
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struct l2tp_tunnel *tunnel,
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u32 session_id);
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struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
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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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struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
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int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id,
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u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
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struct l2tp_tunnel **tunnelp);
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int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
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struct l2tp_tunnel_cfg *cfg);
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void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
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void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
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struct l2tp_session *l2tp_session_create(int priv_size,
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struct l2tp_tunnel *tunnel,
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u32 session_id, u32 peer_session_id,
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struct l2tp_session_cfg *cfg);
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int l2tp_session_register(struct l2tp_session *session,
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struct l2tp_tunnel *tunnel);
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void __l2tp_session_unhash(struct l2tp_session *session);
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int l2tp_session_delete(struct l2tp_session *session);
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void l2tp_session_free(struct l2tp_session *session);
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void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
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unsigned char *ptr, unsigned char *optr, u16 hdrflags,
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int length, int (*payload_hook)(struct sk_buff *skb));
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int l2tp_session_queue_purge(struct l2tp_session *session);
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int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
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void l2tp_session_set_header_len(struct l2tp_session *session, int version);
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int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb,
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int hdr_len);
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int l2tp_nl_register_ops(enum l2tp_pwtype pw_type,
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const struct l2tp_nl_cmd_ops *ops);
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void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
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int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
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static inline 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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static inline 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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/* Session reference counts. Incremented when code obtains a reference
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* to a session.
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*/
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static inline 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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static inline 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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static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
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{
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switch (session->l2specific_type) {
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case L2TP_L2SPECTYPE_DEFAULT:
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return 4;
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case L2TP_L2SPECTYPE_NONE:
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default:
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return 0;
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}
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}
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#define l2tp_printk(ptr, type, func, fmt, ...) \
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do { \
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if (((ptr)->debug) & (type)) \
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func(fmt, ##__VA_ARGS__); \
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} while (0)
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#define l2tp_warn(ptr, type, fmt, ...) \
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l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__)
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#define l2tp_info(ptr, type, fmt, ...) \
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l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__)
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#define l2tp_dbg(ptr, type, fmt, ...) \
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l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__)
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#define MODULE_ALIAS_L2TP_PWTYPE(type) \
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MODULE_ALIAS("net-l2tp-type-" __stringify(type))
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#endif /* _L2TP_CORE_H_ */
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