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   36: .\" Author: Archie Cobbs <archie@freebsd.org>
   37: .\"
   38: .\" $Id: tcp_server.3,v 1.1.1.1 2012/02/21 23:25:53 misho Exp $
   39: .\"
   40: .Dd April 22, 2002
   41: .Dt TCP_SERVER 3
   42: .Os
   43: .Sh NAME
   44: .Nm tcp_server
   45: .Nd generic TCP server
   46: .Sh LIBRARY
   47: PDEL Library (libpdel, \-lpdel)
   48: .Sh SYNOPSIS
   49: .In sys/types.h
   50: .In netinet/in.h
   51: .In stdio.h
   52: .In pdel/net/tcp_server.h
   53: .Ft "struct tcp_server *"
   54: .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"
   55: .Ft "void"
   56: .Fn tcp_server_stop "struct tcp_server **servp"
   57: .Ft "void *"
   58: .Fn tcp_server_get_cookie "struct tcp_server *serv"
   59: .Ft "struct tcp_server *"
   60: .Fn tcp_connection_get_server "struct tcp_connection *conn"
   61: .Ft "void *"
   62: .Fn tcp_connection_get_cookie "struct tcp_connection *conn"
   63: .Ft "int"
   64: .Fn tcp_connection_get_fd "struct tcp_connection *conn"
   65: .Ft "FILE *"
   66: .Fn tcp_connection_get_fp "struct tcp_connection *conn"
   67: .Ft "void"
   68: .Fn tcp_connection_get_peer "struct tcp_connection *conn" "struct sockaddr_in *sin"
   69: .Sh DESCRIPTION
   70: These functions provide support for implementing TCP servers.
   71: .Pp
   72: .Fn tcp_server_start
   73: creates a new TCP server listening for connections on IP address
   74: .Fa ip
   75: and port
   76: .Fa port .
   77: Memory for the
   78: .Nm tcp_server
   79: is dynamically allocated with
   80: .Xr typed_mem 3
   81: type
   82: .Fa mtype .
   83: At most
   84: .Fa max_conn
   85: simultaneous connections will be allowed.
   86: If
   87: .Fa conn_timeout
   88: is non-zero, then if an attempt to read from or write to a peer blocks
   89: for more than
   90: .Fa conn_timeout
   91: seconds, the connection will be terminated.
   92: .Fa ctx
   93: is a
   94: .Xr pevent 3
   95: event context used to listen for incoming connections.
   96: .Pp
   97: The
   98: .Fa setup ,
   99: .Fa handler ,
  100: and
  101: .Fa teardown
  102: arguments are pointers to functions having these types:
  103: .Pp
  104: .Bd -literal -compact -offset 3n
  105: typedef void *tcp_setup_t(struct tcp_connection *conn);
  106: typedef void tcp_handler_t(struct tcp_connection *conn);
  107: typedef void tcp_teardown_t(struct tcp_connection *conn);
  108: .Ed
  109: .Pp
  110: Each connection is represented by a
  111: .Nm tcp_connection
  112: object.
  113: For each new connection,
  114: .Fn setup
  115: is called to initialize user state for the connection.
  116: If setup is unsuccessful,
  117: .Fn setup
  118: should return
  119: .Dv NULL
  120: and set
  121: .Va errno
  122: appropriately, and the connection will be closed.
  123: Otherwise, it should return a non-NULL cookie; this cookie can be
  124: accessed later in
  125: .Fn handler
  126: and
  127: .Fn teardown
  128: by calling 
  129: .Fn tcp_connection_get_cookie .
  130: .Pp
  131: .Fn handler
  132: is used to service the connection.
  133: The thread calling this function may be canceled at any cancellation point;
  134: therefore,
  135: .Fn handler
  136: may need to register cleanup hooks to clean up allocated resources should
  137: that happen.
  138: .Pp
  139: .Fn teardown
  140: is called when
  141: .Fn handler
  142: returns, or the thread is canceled.
  143: If
  144: .Fn setup
  145: returns successfully, 
  146: .Fn teardown
  147: is guaranteed to be called exactly once.
  148: .Pp
  149: .Fn tcp_server_stop
  150: stops and destroys a
  151: .Nm tcp_server .
  152: All existing connection threads are canceled and the current thread
  153: blocks until
  154: .Fn teardown
  155: has been called for each connection.
  156: .Pp
  157: .Fn tcp_connection_get_peer
  158: retrieves the peer's address.
  159: .Pp
  160: .Fn tcp_connection_get_server
  161: returns the
  162: .Nm tcp_server
  163: object associated with the connection
  164: .Fa conn .
  165: .Pp
  166: .Fn tcp_connection_get_fd
  167: returns the TCP socket associated with the connection.
  168: .Pp
  169: .Fn tcp_connection_get_fp
  170: returns a stream opened on top of the socket for use with stream based I/O.
  171: .Pp
  172: The user code should
  173: .Em not
  174: close either the socket or the stream; these will be closed automatically
  175: when the connection is terminated.
  176: .Sh RETURN VALUES
  177: .Fn tcp_server_start
  178: returns
  179: .Dv NULL
  180: to indicate an error, with
  181: .Va errno
  182: set appropriately.
  183: .Sh SEE ALSO
  184: .Xr libpdel 3 ,
  185: .Xr pevent 3 ,
  186: .Xr typed_mem 3
  187: .Sh HISTORY
  188: The PDEL library was developed at Packet Design, LLC.
  189: .Dv "http://www.packetdesign.com/"
  190: .Sh AUTHORS
  191: .An Archie Cobbs Aq archie@freebsd.org