diff options
Diffstat (limited to 'net/l2tp/l2tp_core.h')
| -rw-r--r-- | net/l2tp/l2tp_core.h | 229 |
1 files changed, 119 insertions, 110 deletions
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 2db3d50d10a4..a88e070b431d 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -1,6 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0-only */ -/* - * L2TP internal definitions. +/* L2TP internal definitions. * * Copyright (c) 2008,2009 Katalix Systems Ltd */ @@ -16,17 +15,17 @@ #include <net/xfrm.h> #endif -/* Just some random numbers */ +/* Random numbers used for internal consistency checks of tunnel and session structures */ #define L2TP_TUNNEL_MAGIC 0x42114DDA #define L2TP_SESSION_MAGIC 0x0C04EB7D -/* Per tunnel, session hash table size */ +/* Per tunnel session hash table size */ #define L2TP_HASH_BITS 4 -#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS) +#define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS) -/* System-wide, session hash table size */ +/* System-wide session hash table size */ #define L2TP_HASH_BITS_2 8 -#define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2) +#define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2) struct sk_buff; @@ -40,41 +39,39 @@ struct l2tp_stats { atomic_long_t rx_oos_packets; atomic_long_t rx_errors; atomic_long_t rx_cookie_discards; + atomic_long_t rx_invalid; }; struct l2tp_tunnel; -/* Describes a session. Contains information to determine incoming - * packets and transmit outgoing ones. - */ +/* L2TP session configuration */ struct l2tp_session_cfg { enum l2tp_pwtype pw_type; - 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 */ + 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 LNS control. + */ 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 reorder_timeout; /* configured reorder timeout (in jiffies) */ char *ifname; }; +/* Represents a session (pseudowire) instance. + * Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics. + * Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into + * an additional per-net ("global") hashlist. + */ +#define L2TP_SESSION_NAME_MAX 32 struct l2tp_session { - int magic; /* should be - * L2TP_SESSION_MAGIC */ + int magic; /* should be L2TP_SESSION_MAGIC */ long dead; - struct l2tp_tunnel *tunnel; /* back pointer to tunnel - * context */ + struct l2tp_tunnel *tunnel; /* back pointer to tunnel context */ u32 session_id; u32 peer_session_id; u8 cookie[8]; @@ -89,42 +86,51 @@ struct l2tp_session { 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; /* for OOS recovery */ int nr_oos_count_max; - struct hlist_node hlist; /* Hash list node */ + struct hlist_node hlist; /* hash list node */ refcount_t ref_count; - char name[32]; /* for logging */ + char name[L2TP_SESSION_NAME_MAX]; /* for logging */ char ifname[IFNAMSIZ]; - 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) */ + 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 LNS control. + */ + int reorder_timeout; /* configured reorder timeout (in jiffies) */ int reorder_skip; /* set if skip to next nr */ enum l2tp_pwtype pwtype; struct l2tp_stats stats; - struct hlist_node global_hlist; /* Global hash list node */ + struct hlist_node global_hlist; /* global hash list node */ - int (*build_header)(struct l2tp_session *session, void *buf); + /* Session receive handler for data packets. + * Each pseudowire implementation should implement this callback in order to + * handle incoming packets. Packets are passed to the pseudowire handler after + * reordering, if data sequence numbers are enabled for the session. + */ void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len); + + /* Session close handler. + * Each pseudowire implementation may implement this callback in order to carry + * out pseudowire-specific shutdown actions. + * The callback is called by core after unhashing the session and purging its + * reorder queue. + */ void (*session_close)(struct l2tp_session *session); + + /* Session show handler. + * Pseudowire-specific implementation of debugfs session rendering. + * The callback is called by l2tp_debugfs.c after rendering core session + * information. + */ void (*show)(struct seq_file *m, void *priv); - uint8_t priv[0]; /* private data */ + + u8 priv[]; /* private data */ }; -/* Describes the tunnel. It contains info to track all the associated - * sessions so incoming packets can be sorted out - */ +/* L2TP tunnel configuration */ struct l2tp_tunnel_cfg { - int debug; /* bitmask of debug message - * categories */ enum l2tp_encap_type encap; /* Used only for kernel-created sockets */ @@ -141,47 +147,64 @@ struct l2tp_tunnel_cfg { udp6_zero_rx_checksums:1; }; +/* Represents a tunnel instance. + * Tracks runtime state including IO statistics. + * Holds the tunnel socket (either passed from userspace or directly created by the kernel). + * Maintains a hashlist of sessions belonging to the tunnel instance. + * Is linked into a per-net list of tunnels. + */ +#define L2TP_TUNNEL_NAME_MAX 20 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. + spinlock_t hlist_lock; /* write-protection for 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 */ + /* 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 */ + char name[L2TP_TUNNEL_NAME_MAX]; /* for logging */ enum l2tp_encap_type encap; struct l2tp_stats stats; - struct list_head list; /* Keep a list of all tunnels */ + struct list_head list; /* list node on per-namespace list of tunnels */ struct net *l2tp_net; /* the net we belong to */ refcount_t ref_count; - void (*old_sk_destruct)(struct sock *); - struct sock *sock; /* Parent socket */ - int fd; /* Parent fd, if tunnel socket - * was created by userspace */ + void (*old_sk_destruct)(struct sock *sk); + struct sock *sock; /* parent socket */ + int fd; /* parent fd, if tunnel socket was created + * by userspace + */ struct work_struct del_work; }; +/* Pseudowire ops callbacks for use with the l2tp genetlink interface */ struct l2tp_nl_cmd_ops { + /* The pseudowire session create callback is responsible for creating a session + * instance for a specific pseudowire type. + * It must call l2tp_session_create and l2tp_session_register to register the + * session instance, as well as carry out any pseudowire-specific initialisation. + * It must return >= 0 on success, or an appropriate negative errno value on failure. + */ 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); + + /* The pseudowire session delete callback is responsible for initiating the deletion + * of a session instance. + * It must call l2tp_session_delete, as well as carry out any pseudowire-specific + * teardown actions. + */ + void (*session_delete)(struct l2tp_session *session); }; static inline void *l2tp_session_priv(struct l2tp_session *session) @@ -189,73 +212,72 @@ static inline void *l2tp_session_priv(struct l2tp_session *session) return &session->priv[0]; } +/* Tunnel and session refcounts */ +void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel); +void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel); +void l2tp_session_inc_refcount(struct l2tp_session *session); +void l2tp_session_dec_refcount(struct l2tp_session *session); + +/* Tunnel and session lookup. + * These functions take a reference on the instances they return, so + * the caller must ensure that the reference is dropped appropriately. + */ struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id); struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth); struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel, u32 session_id); -void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); - struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id); struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth); struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net, const char *ifname); -int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, +/* Tunnel and session lifetime management. + * Creation of a new instance is a two-step process: create, then register. + * Destruction is triggered using the *_delete functions, and completes asynchronously. + */ +int l2tp_tunnel_create(int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp); int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, struct l2tp_tunnel_cfg *cfg); - 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_delete(struct l2tp_session *session); -void __l2tp_session_unhash(struct l2tp_session *session); -int l2tp_session_delete(struct l2tp_session *session); -void l2tp_session_free(struct l2tp_session *session); +/* Receive path helpers. If data sequencing is enabled for the session these + * functions handle queuing and reordering prior to passing packets to the + * pseudowire code to be passed to userspace. + */ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, unsigned char *ptr, unsigned char *optr, u16 hdrflags, int length); 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); +/* Transmit path helpers for sending packets over the tunnel socket. */ +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 l2tp_nl_register_ops(enum l2tp_pwtype pw_type, - const struct l2tp_nl_cmd_ops *ops); +/* Pseudowire management. + * Pseudowires should register with l2tp core on module init, and unregister + * on module exit. + */ +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) -{ - refcount_inc(&tunnel->ref_count); -} - -static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel) -{ - if (refcount_dec_and_test(&tunnel->ref_count)) - l2tp_tunnel_free(tunnel); -} +/* IOCTL helper for IP encap modules. */ +int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); -/* Session reference counts. Incremented when code obtains a reference - * to a session. +/* Extract the tunnel structure from a socket's sk_user_data pointer, + * validating the tunnel magic feather. */ -static inline void l2tp_session_inc_refcount(struct l2tp_session *session) -{ - refcount_inc(&session->ref_count); -} - -static inline void l2tp_session_dec_refcount(struct l2tp_session *session) -{ - if (refcount_dec_and_test(&session->ref_count)) - l2tp_session_free(session); -} +struct l2tp_tunnel *l2tp_sk_to_tunnel(struct sock *sk); static inline int l2tp_get_l2specific_len(struct l2tp_session *session) { @@ -318,19 +340,6 @@ static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, str 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)) |