--- /dev/null
+/*
+ * 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)
+
+/* Debug message categories for the DEBUG socket option */
+enum {
+ L2TP_MSG_DEBUG = (1 << 0), /* verbose debug (if
+ * compiled in) */
+ L2TP_MSG_CONTROL = (1 << 1), /* userspace - kernel
+ * interface */
+ L2TP_MSG_SEQ = (1 << 2), /* sequence numbers */
+ L2TP_MSG_DATA = (1 << 3), /* data packets */
+};
+
+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 offset; /* offset to payload */
+ 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 */
+
+ 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 offset; /* offset from end of L2TP header
+ to beginning of data */
+ 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 defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+ 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 */
+ struct rcu_head rcu;
+ rwlock_t hlist_lock; /* protect session_hlist */
+ 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, u32 tunnel_id, 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_session *l2tp_session_find(struct net *net,
+ struct l2tp_tunnel *tunnel,
+ u32 session_id);
+struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth);
+struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname);
+struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
+struct l2tp_tunnel *l2tp_tunnel_find_nth(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);
+int 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);
+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);
+
+/* 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
+
+#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__)
+
+#endif /* _L2TP_CORE_H_ */
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