/* * L2TP internal definitions. * * Copyright (c) 2008,2009 Katalix Systems Ltd * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #ifndef _L2TP_CORE_H_ #define _L2TP_CORE_H_ /* Just some random numbers */ #define L2TP_TUNNEL_MAGIC 0x42114DDA #define L2TP_SESSION_MAGIC 0x0C04EB7D /* Per tunnel, session hash table size */ #define L2TP_HASH_BITS 4 #define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS) /* System-wide, session hash table size */ #define L2TP_HASH_BITS_2 8 #define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2) struct sk_buff; struct l2tp_stats { atomic_long_t tx_packets; atomic_long_t tx_bytes; atomic_long_t tx_errors; atomic_long_t rx_packets; atomic_long_t rx_bytes; atomic_long_t rx_seq_discards; atomic_long_t rx_oos_packets; atomic_long_t rx_errors; atomic_long_t rx_cookie_discards; }; struct l2tp_tunnel; /* Describes a session. Contains information to determine incoming * packets and transmit outgoing ones. */ struct l2tp_session_cfg { enum l2tp_pwtype pw_type; unsigned int data_seq:2; /* data sequencing level * 0 => none, 1 => IP only, * 2 => all */ unsigned int recv_seq:1; /* expect receive packets with * sequence numbers? */ unsigned int send_seq:1; /* send packets with sequence * numbers? */ unsigned int lns_mode:1; /* behave as LNS? LAC enables * sequence numbers under * control of LNS. */ int debug; /* bitmask of debug message * categories */ u16 vlan_id; /* VLAN pseudowire only */ u16 l2specific_len; /* Layer 2 specific length */ u16 l2specific_type; /* Layer 2 specific type */ u8 cookie[8]; /* optional cookie */ int cookie_len; /* 0, 4 or 8 bytes */ u8 peer_cookie[8]; /* peer's cookie */ int peer_cookie_len; /* 0, 4 or 8 bytes */ int reorder_timeout; /* configured reorder timeout * (in jiffies) */ int mtu; int mru; char *ifname; }; struct l2tp_session { int magic; /* should be * L2TP_SESSION_MAGIC */ long dead; struct l2tp_tunnel *tunnel; /* back pointer to tunnel * context */ u32 session_id; u32 peer_session_id; u8 cookie[8]; int cookie_len; u8 peer_cookie[8]; int peer_cookie_len; u16 l2specific_len; u16 l2specific_type; u16 hdr_len; u32 nr; /* session NR state (receive) */ u32 ns; /* session NR state (send) */ struct sk_buff_head reorder_q; /* receive reorder queue */ u32 nr_max; /* max NR. Depends on tunnel */ u32 nr_window_size; /* NR window size */ u32 nr_oos; /* NR of last OOS packet */ int nr_oos_count; /* For OOS recovery */ int nr_oos_count_max; struct hlist_node hlist; /* Hash list node */ atomic_t ref_count; char name[32]; /* for logging */ char ifname[IFNAMSIZ]; unsigned int data_seq:2; /* data sequencing level * 0 => none, 1 => IP only, * 2 => all */ unsigned int recv_seq:1; /* expect receive packets with * sequence numbers? */ unsigned int send_seq:1; /* send packets with sequence * numbers? */ unsigned int lns_mode:1; /* behave as LNS? LAC enables * sequence numbers under * control of LNS. */ int debug; /* bitmask of debug message * categories */ int reorder_timeout; /* configured reorder timeout * (in jiffies) */ int reorder_skip; /* set if skip to next nr */ int mtu; int mru; enum l2tp_pwtype pwtype; struct l2tp_stats stats; struct hlist_node global_hlist; /* Global hash list node */ int (*build_header)(struct l2tp_session *session, void *buf); void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); void (*session_close)(struct l2tp_session *session); void (*ref)(struct l2tp_session *session); void (*deref)(struct l2tp_session *session); #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) void (*show)(struct seq_file *m, void *priv); #endif uint8_t priv[0]; /* private data */ }; /* Describes the tunnel. It contains info to track all the associated * sessions so incoming packets can be sorted out */ struct l2tp_tunnel_cfg { int debug; /* bitmask of debug message * categories */ enum l2tp_encap_type encap; /* Used only for kernel-created sockets */ struct in_addr local_ip; struct in_addr peer_ip; #if IS_ENABLED(CONFIG_IPV6) struct in6_addr *local_ip6; struct in6_addr *peer_ip6; #endif u16 local_udp_port; u16 peer_udp_port; unsigned int use_udp_checksums:1, udp6_zero_tx_checksums:1, udp6_zero_rx_checksums:1; }; struct l2tp_tunnel { int magic; /* Should be L2TP_TUNNEL_MAGIC */ unsigned long dead; struct rcu_head rcu; rwlock_t hlist_lock; /* protect session_hlist */ bool acpt_newsess; /* Indicates whether this * tunnel accepts new sessions. * Protected by hlist_lock. */ struct hlist_head session_hlist[L2TP_HASH_SIZE]; /* hashed list of sessions, * hashed by id */ u32 tunnel_id; u32 peer_tunnel_id; int version; /* 2=>L2TPv2, 3=>L2TPv3 */ char name[20]; /* for logging */ int debug; /* bitmask of debug message * categories */ enum l2tp_encap_type encap; struct l2tp_stats stats; struct list_head list; /* Keep a list of all tunnels */ struct net *l2tp_net; /* the net we belong to */ atomic_t ref_count; #ifdef CONFIG_DEBUG_FS void (*show)(struct seq_file *m, void *arg); #endif int (*recv_payload_hook)(struct sk_buff *skb); void (*old_sk_destruct)(struct sock *); struct sock *sock; /* Parent socket */ int fd; /* Parent fd, if tunnel socket * was created by userspace */ #if IS_ENABLED(CONFIG_IPV6) bool v4mapped; #endif struct work_struct del_work; uint8_t priv[0]; /* private data */ }; struct l2tp_nl_cmd_ops { int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg); int (*session_delete)(struct l2tp_session *session); }; static inline void *l2tp_tunnel_priv(struct l2tp_tunnel *tunnel) { return &tunnel->priv[0]; } static inline void *l2tp_session_priv(struct l2tp_session *session) { return &session->priv[0]; } static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk) { struct l2tp_tunnel *tunnel; if (sk == NULL) return NULL; sock_hold(sk); tunnel = (struct l2tp_tunnel *)(sk->sk_user_data); if (tunnel == NULL) { sock_put(sk); goto out; } BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); out: return tunnel; } struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); struct l2tp_session *l2tp_session_get(const struct net *net, struct l2tp_tunnel *tunnel, u32 session_id, bool do_ref); struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth, bool do_ref); struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, const char *ifname, bool do_ref); struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id); struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth); int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp); void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel); 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); int l2tp_session_register(struct l2tp_session *session, struct l2tp_tunnel *tunnel); void __l2tp_session_unhash(struct l2tp_session *session); int l2tp_session_delete(struct l2tp_session *session); void l2tp_session_free(struct l2tp_session *session); void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length, int (*payload_hook)(struct sk_buff *skb)); int l2tp_session_queue_purge(struct l2tp_session *session); int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb); void l2tp_session_set_header_len(struct l2tp_session *session, int version); int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len); int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops); void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type); int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); static inline void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel) { atomic_inc(&tunnel->ref_count); } static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) { if (atomic_dec_and_test(&tunnel->ref_count)) kfree_rcu(tunnel, rcu); } /* Session reference counts. Incremented when code obtains a reference * to a session. */ static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) { atomic_inc(&session->ref_count); } static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) { if (atomic_dec_and_test(&session->ref_count)) l2tp_session_free(session); } #ifdef L2TP_REFCNT_DEBUG #define l2tp_session_inc_refcount(_s) \ do { \ pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ __func__, __LINE__, (_s)->name, \ atomic_read(&_s->ref_count)); \ l2tp_session_inc_refcount_1(_s); \ } while (0) #define l2tp_session_dec_refcount(_s) \ do { \ pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ __func__, __LINE__, (_s)->name, \ atomic_read(&_s->ref_count)); \ l2tp_session_dec_refcount_1(_s); \ } while (0) #else #define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s) #define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s) #endif static inline int l2tp_get_l2specific_len(struct l2tp_session *session) { switch (session->l2specific_type) { case L2TP_L2SPECTYPE_DEFAULT: return 4; case L2TP_L2SPECTYPE_NONE: default: return 0; } } static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb, unsigned char **ptr, unsigned char **optr) { int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session); if (opt_len > 0) { int off = *ptr - *optr; if (!pskb_may_pull(skb, off + opt_len)) return -1; if (skb->data != *optr) { *optr = skb->data; *ptr = skb->data + off; } } return 0; } #define l2tp_printk(ptr, type, func, fmt, ...) \ do { \ if (((ptr)->debug) & (type)) \ func(fmt, ##__VA_ARGS__); \ } while (0) #define l2tp_warn(ptr, type, fmt, ...) \ l2tp_printk(ptr, type, pr_warn, fmt, ##__VA_ARGS__) #define l2tp_info(ptr, type, fmt, ...) \ l2tp_printk(ptr, type, pr_info, fmt, ##__VA_ARGS__) #define l2tp_dbg(ptr, type, fmt, ...) \ l2tp_printk(ptr, type, pr_debug, fmt, ##__VA_ARGS__) #define MODULE_ALIAS_L2TP_PWTYPE(type) \ MODULE_ALIAS("net-l2tp-type-" __stringify(type)) #endif /* _L2TP_CORE_H_ */