V8/usr/man/man3/tcp.3

.TH TCP 3 
.SH NAME
tcp_sock, tcp_conn, tcp_listen, tcp_accept, tcp_rcmd \- tcp operations
.SH SYNOPSIS
.nf
.B #include <sys/inet/tcp_user.h>
.PP
.B tcp_sock();
.PP
.B tcp_connect(fd, lport, faddr, fport)
.B int fd;
.B tcp_port lport, fport;
.B in_addr faddr;
.PP
.B tcp_listen(fd, lport, faddr, fport)
.B int fd;
.B tcp_port lport, fport;
.B in_addr faddr;
.PP
.B tcp_accept(fd, faddrp, fportp, devp)
.B int fd, *devp;
.B in_addr *faddrp;
.B tcp_port *fportp;
.PP
.B tcp_rcmd(host, port, locuser, remuser, cmd, fd2p)
.B char *host, *port, *locuser, *remuser, *cmd;
.B int *fd2p;
.PP
.SH DESCRIPTION
These routines are loaded by the 
.B \-lin
option of
.IR ld (1).
.PP
TCP is one of the many protocols which are layered
upon IP (internet protocol).
It provides full duplex byte stream connections between
end points called sockets.
The address of a socket is composed of the internet address
of its host and the port number to which
the socket is bound.
.PP
.I Tcp_sock
returns the file descriptor of an unbound socket.
Once opened, a socket may be bound to a port number within the
host and set up as the active or passive end of a connection.
.I Tcp_sock
returns -1 if no sockets are available.
.PP
.I Tcp_connect
binds socket
.I fd
to port
.I lport
and attempts to set up a connection to
the socket bound to port
.I fport
on host
.I faddr.
.I Tcp_connect
returns 0 if the connection is established, -1 otherwise.
Communications proceeds by performing 
.IR read (2)
and 
.IR write (2)
on
.I fd.
.PP
.I Tcp_listen
binds socket
.I fd
to port
.I lport
and configures the socket to listen for connection requests to that port.
If 
.I faddr
and
.I fport
are non-zero, only connections coming from sockets on machine
.I faddr
and bound to port
.I fport
are listened for.
.I Tcp_listen
returns 0 on success, -1 otherwise.
.IR Select (2)
can be used with a listening socket to provide asynchronous polling of
connection requests.
.PP
.I Tcp_accept
waits for and accepts a connection request sent to the listening socket
.I fd.
When a connection arrives, tcp_accept fills in 
.I faddr
and
.I fport
with the identity of the connector and returns a new fd
over which communications can proceed.
.I Fd
is left open and continues listening for connections.
.PP
.I Tcp_rcmd
remotely executes a 
.I cmd
on 
.I host
as user
.I remuser.
Standard input is attached to
.I cmd's 
standard input and
.I cmd's
standard output is attached to standard output.
If 
.I fd2p
is non-zero, it is filled with the fd of a new TCP connection attached
to 
.I cmd's
standard error.
Otherwise,
.I cmd's
standard error is attached to its standard output.
.SH FILES
.nf
/dev/tcp*	the socket devices
.SH SEE ALSO
internet(3), udp(3)