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author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-30 19:09:18 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-30 19:09:18 +0000 |
commit | b0d61785cae024b1f44119446a940ee14c9ac959 (patch) | |
tree | 5a495a583b002ae9e57f09848ae697160708c220 /share/man/man4/tcp.4 | |
parent | d43599f73ba5858e573c7ad8b284f6a0808c5c93 (diff) | |
download | FreeBSD-src-b0d61785cae024b1f44119446a940ee14c9ac959.zip FreeBSD-src-b0d61785cae024b1f44119446a940ee14c9ac959.tar.gz |
BSD 4.4 Lite Share Sources
Diffstat (limited to 'share/man/man4/tcp.4')
-rw-r--r-- | share/man/man4/tcp.4 | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/share/man/man4/tcp.4 b/share/man/man4/tcp.4 new file mode 100644 index 0000000..21f49d5 --- /dev/null +++ b/share/man/man4/tcp.4 @@ -0,0 +1,178 @@ +.\" Copyright (c) 1983, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)tcp.4 8.1 (Berkeley) 6/5/93 +.\" +.Dd June 5, 1993 +.Dt TCP 4 +.Os BSD 4.2 +.Sh NAME +.Nm tcp +.Nd Internet Transmission Control Protocol +.Sh SYNOPSIS +.Fd #include <sys/socket.h> +.Fd #include <netinet/in.h> +.Ft int +.Fn socket AF_INET SOCK_STREAM 0 +.Sh DESCRIPTION +The +.Tn TCP +protocol provides reliable, flow-controlled, two-way +transmission of data. It is a byte-stream protocol used to +support the +.Dv SOCK_STREAM +abstraction. TCP uses the standard +Internet address format and, in addition, provides a per-host +collection of +.Dq port addresses . +Thus, each address is composed +of an Internet address specifying the host and network, with +a specific +.Tn TCP +port on the host identifying the peer entity. +.Pp +Sockets utilizing the tcp protocol are either +.Dq active +or +.Dq passive . +Active sockets initiate connections to passive +sockets. By default +.Tn TCP +sockets are created active; to create a +passive socket the +.Xr listen 2 +system call must be used +after binding the socket with the +.Xr bind 2 +system call. Only +passive sockets may use the +.Xr accept 2 +call to accept incoming connections. Only active sockets may +use the +.Xr connect 2 +call to initiate connections. +.Pp +Passive sockets may +.Dq underspecify +their location to match +incoming connection requests from multiple networks. This +technique, termed +.Dq wildcard addressing , +allows a single +server to provide service to clients on multiple networks. +To create a socket which listens on all networks, the Internet +address +.Dv INADDR_ANY +must be bound. The +.Tn TCP +port may still be specified +at this time; if the port is not specified the system will assign one. +Once a connection has been established the socket's address is +fixed by the peer entity's location. The address assigned the +socket is the address associated with the network interface +through which packets are being transmitted and received. Normally +this address corresponds to the peer entity's network. +.Pp +.Tn TCP +supports one socket option which is set with +.Xr setsockopt 2 +and tested with +.Xr getsockopt 2 . +Under most circumstances, +.Tn TCP +sends data when it is presented; +when outstanding data has not yet been acknowledged, it gathers +small amounts of output to be sent in a single packet once +an acknowledgement is received. +For a small number of clients, such as window systems +that send a stream of mouse events which receive no replies, +this packetization may cause significant delays. +Therefore, +.Tn TCP +provides a boolean option, +.Dv TCP_NODELAY +(from +.Aq Pa netinet/tcp.h , +to defeat this algorithm. +The option level for the +.Xr setsockopt +call is the protocol number for +.Tn TCP , +available from +.Xr getprotobyname 3 . +.Pp +Options at the +.Tn IP +transport level may be used with +.Tn TCP ; +see +.Xr ip 4 . +Incoming connection requests that are source-routed are noted, +and the reverse source route is used in responding. +.Sh DIAGNOSTICS +A socket operation may fail with one of the following errors returned: +.Bl -tag -width [EADDRNOTAVAIL] +.It Bq Er EISCONN +when trying to establish a connection on a socket which +already has one; +.It Bq Er ENOBUFS +when the system runs out of memory for +an internal data structure; +.It Bq Er ETIMEDOUT +when a connection was dropped +due to excessive retransmissions; +.It Bq Er ECONNRESET +when the remote peer +forces the connection to be closed; +.It Bq Er ECONNREFUSED +when the remote +peer actively refuses connection establishment (usually because +no process is listening to the port); +.It Bq Er EADDRINUSE +when an attempt +is made to create a socket with a port which has already been +allocated; +.It Bq Er EADDRNOTAVAIL +when an attempt is made to create a +socket with a network address for which no network interface +exists. +.El +.Sh SEE ALSO +.Xr getsockopt 2 , +.Xr socket 2 , +.Xr intro 4 , +.Xr inet 4 , +.Xr ip 4 +.Sh HISTORY +The +.Nm +protocol stack appeared in +.Bx 4.2 . |