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.\" Author: Archie Cobbs <archie@freebsd.org>
.\"
.\" $Id: tcp_server.3,v 1.1.1.1 2012/02/21 23:25:53 misho Exp $
.\"
.Dd April 22, 2002
.Dt TCP_SERVER 3
.Os
.Sh NAME
.Nm tcp_server
.Nd generic TCP server
.Sh LIBRARY
PDEL Library (libpdel, \-lpdel)
.Sh SYNOPSIS
.In sys/types.h
.In netinet/in.h
.In stdio.h
.In pdel/net/tcp_server.h
.Ft "struct tcp_server *"
.Fn 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"
.Ft "void"
.Fn tcp_server_stop "struct tcp_server **servp"
.Ft "void *"
.Fn tcp_server_get_cookie "struct tcp_server *serv"
.Ft "struct tcp_server *"
.Fn tcp_connection_get_server "struct tcp_connection *conn"
.Ft "void *"
.Fn tcp_connection_get_cookie "struct tcp_connection *conn"
.Ft "int"
.Fn tcp_connection_get_fd "struct tcp_connection *conn"
.Ft "FILE *"
.Fn tcp_connection_get_fp "struct tcp_connection *conn"
.Ft "void"
.Fn tcp_connection_get_peer "struct tcp_connection *conn" "struct sockaddr_in *sin"
.Sh DESCRIPTION
These functions provide support for implementing TCP servers.
.Pp
.Fn tcp_server_start
creates a new TCP server listening for connections on IP address
.Fa ip
and port
.Fa port .
Memory for the
.Nm tcp_server
is dynamically allocated with
.Xr typed_mem 3
type
.Fa mtype .
At most
.Fa max_conn
simultaneous connections will be allowed.
If
.Fa conn_timeout
is non-zero, then if an attempt to read from or write to a peer blocks
for more than
.Fa conn_timeout
seconds, the connection will be terminated.
.Fa ctx
is a
.Xr pevent 3
event context used to listen for incoming connections.
.Pp
The
.Fa setup ,
.Fa handler ,
and
.Fa teardown
arguments are pointers to functions having these types:
.Pp
.Bd -literal -compact -offset 3n
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);
.Ed
.Pp
Each connection is represented by a
.Nm tcp_connection
object.
For each new connection,
.Fn setup
is called to initialize user state for the connection.
If setup is unsuccessful,
.Fn setup
should return
.Dv NULL
and set
.Va errno
appropriately, and the connection will be closed.
Otherwise, it should return a non-NULL cookie; this cookie can be
accessed later in
.Fn handler
and
.Fn teardown
by calling 
.Fn tcp_connection_get_cookie .
.Pp
.Fn handler
is used to service the connection.
The thread calling this function may be canceled at any cancellation point;
therefore,
.Fn handler
may need to register cleanup hooks to clean up allocated resources should
that happen.
.Pp
.Fn teardown
is called when
.Fn handler
returns, or the thread is canceled.
If
.Fn setup
returns successfully, 
.Fn teardown
is guaranteed to be called exactly once.
.Pp
.Fn tcp_server_stop
stops and destroys a
.Nm tcp_server .
All existing connection threads are canceled and the current thread
blocks until
.Fn teardown
has been called for each connection.
.Pp
.Fn tcp_connection_get_peer
retrieves the peer's address.
.Pp
.Fn tcp_connection_get_server
returns the
.Nm tcp_server
object associated with the connection
.Fa conn .
.Pp
.Fn tcp_connection_get_fd
returns the TCP socket associated with the connection.
.Pp
.Fn tcp_connection_get_fp
returns a stream opened on top of the socket for use with stream based I/O.
.Pp
The user code should
.Em not
close either the socket or the stream; these will be closed automatically
when the connection is terminated.
.Sh RETURN VALUES
.Fn tcp_server_start
returns
.Dv NULL
to indicate an error, with
.Va errno
set appropriately.
.Sh SEE ALSO
.Xr libpdel 3 ,
.Xr pevent 3 ,
.Xr typed_mem 3
.Sh HISTORY
The PDEL library was developed at Packet Design, LLC.
.Dv "http://www.packetdesign.com/"
.Sh AUTHORS
.An Archie Cobbs Aq archie@freebsd.org