diff options
Diffstat (limited to 'net/l2tp/l2tp_core.h')
| -rw-r--r-- | net/l2tp/l2tp_core.h | 86 |
1 files changed, 72 insertions, 14 deletions
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 3dfd3ddd28fd..3468d6b177a0 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -15,15 +15,15 @@ #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 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 BIT(L2TP_HASH_BITS_2) @@ -43,9 +43,7 @@ struct l2tp_stats { 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? */ @@ -63,6 +61,11 @@ struct l2tp_session_cfg { 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. + */ struct l2tp_session { int magic; /* should be L2TP_SESSION_MAGIC */ long dead; @@ -101,15 +104,32 @@ struct l2tp_session { struct l2tp_stats stats; struct hlist_node global_hlist; /* global hash list node */ + /* 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); + 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; @@ -128,6 +148,12 @@ 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. + */ struct l2tp_tunnel { int magic; /* Should be L2TP_TUNNEL_MAGIC */ @@ -162,10 +188,23 @@ struct l2tp_tunnel { 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); + + /* 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); }; @@ -174,11 +213,16 @@ 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, @@ -189,33 +233,47 @@ 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); +/* 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(struct net *net, 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); + +/* 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); +/* 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 hdr_len); -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); + +/* IOCTL helper for IP encap modules. */ int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); static inline int l2tp_get_l2specific_len(struct l2tp_session *session) |