TCP_SERVER(3)

NAME
tcp_server - generic TCP server

LIBRARY
PDEL Library (libpdel, -lpdel)

SYNOPSIS
#include <sys/types.h>
#include <netinet/in.h>
#include <stdio.h>
#include <pdel/net/tcp_server.h>
struct tcp_server *
tcp_server_start(struct pevent_ctx *ctx, void *cookie, const char *mtype, struct in_addr ip, u_int16_t port, u_int max_conn, u_int conn_timeout, tcp_setup_t *setup, tcp_handler_t *handler, tcp_teardown_t *teardown);
void
tcp_server_stop(struct tcp_server **servp);
void *
tcp_server_get_cookie(struct tcp_server *serv);
struct tcp_server *
tcp_connection_get_server(struct tcp_connection *conn);
void *
tcp_connection_get_cookie(struct tcp_connection *conn);
int
tcp_connection_get_fd(struct tcp_connection *conn);
FILE *
tcp_connection_get_fp(struct tcp_connection *conn);
void
tcp_connection_get_peer(struct tcp_connection *conn, struct sockaddr_in *sin);

DESCRIPTION
These functions provide support for implementing TCP servers.

tcp_server_start() creates a new TCP server listening for connections on IP address ip and port port. Memory for the tcp_server is dynamically allocated with typed_mem(3) type mtype. At most max_conn simultaneous connections will be allowed. If conn_timeout is non-zero, then if an attempt to read from or write to a peer blocks for more than conn_timeout seconds, the connection will be terminated. ctx is a pevent(3) event context used to listen for incoming connections.

The setup, handler, and teardown arguments are pointers to functions having these types:

    typedef void *tcp_setup_t(struct tcp_connection *conn);
    typedef void tcp_handler_t(struct tcp_connection *conn);
    typedef void tcp_teardown_t(struct tcp_connection *conn);

Each connection is represented by a tcp_connection object. For each new connection, setup() is called to initialize user state for the connection. If setup is unsuccessful, setup() should return NULL and set errno appropriately, and the connection will be closed. Otherwise, it should return a non-NULL cookie; this cookie can be accessed later in handler() and teardown() by calling tcp_connection_get_cookie().

handler() is used to service the connection. The thread calling this function may be canceled at any cancellation point; therefore, handler() may need to register cleanup hooks to clean up allocated resources should that happen.

teardown() is called when handler() returns, or the thread is canceled. If setup() returns successfully, teardown() is guaranteed to be called exactly once.

tcp_server_stop() stops and destroys a tcp_server. All existing connection threads are canceled and the current thread blocks until teardown() has been called for each connection.

tcp_connection_get_peer() retrieves the peer's address.

tcp_connection_get_server() returns the tcp_server object associated with the connection conn.

tcp_connection_get_fd() returns the TCP socket associated with the connection.

tcp_connection_get_fp() returns a stream opened on top of the socket for use with stream based I/O.

The user code should not close either the socket or the stream; these will be closed automatically when the connection is terminated.

RETURN VALUES
tcp_server_start() returns NULL to indicate an error, with errno set appropriately.

SEE ALSO
libpdel(3), pevent(3), typed_mem(3)

HISTORY
The PDEL library was developed at Packet Design, LLC. http://www.packetdesign.com/

AUTHORS
Archie Cobbs <archie@freebsd.org>