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diff --git a/static/netbsd/man4/tcp.4 3.html b/static/netbsd/man4/tcp.4 3.html deleted file mode 100644 index 1de8958a..00000000 --- a/static/netbsd/man4/tcp.4 3.html +++ /dev/null @@ -1,235 +0,0 @@ -<table class="head"> - <tr> - <td class="head-ltitle">TCP(4)</td> - <td class="head-vol">Device Drivers Manual</td> - <td class="head-rtitle">TCP(4)</td> - </tr> -</table> -<div class="manual-text"> -<section class="Sh"> -<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> -<p class="Pp"><code class="Nm">tcp</code> — <span class="Nd">Internet - Transmission Control Protocol</span></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> -<p class="Pp"><code class="In">#include - <<a class="In">sys/socket.h</a>></code> - <br/> - <code class="In">#include <<a class="In">netinet/in.h</a>></code></p> -<p class="Pp"><var class="Ft">int</var> - <br/> - <code class="Fn">socket</code>(<var class="Fa" style="white-space: nowrap;">AF_INET</var>, - <var class="Fa" style="white-space: nowrap;">SOCK_STREAM</var>, - <var class="Fa" style="white-space: nowrap;">0</var>);</p> -<p class="Pp"><var class="Ft">int</var> - <br/> - <code class="Fn">socket</code>(<var class="Fa" style="white-space: nowrap;">AF_INET6</var>, - <var class="Fa" style="white-space: nowrap;">SOCK_STREAM</var>, - <var class="Fa" style="white-space: nowrap;">0</var>);</p> -</section> -<section class="Sh"> -<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> -<p class="Pp">The TCP provides reliable, flow-controlled, two-way transmission - of data. It is a byte-stream protocol used to support the - <code class="Dv">SOCK_STREAM</code> abstraction. TCP uses the standard - Internet address format and, in addition, provides a per-host collection of - “port addresses”. Thus, each address is composed of an - Internet address specifying the host and network, with a specific TCP port - on the host identifying the peer entity.</p> -<p class="Pp">Sockets using TCP are either “active” or - “passive”. Active sockets initiate connections to passive - sockets. By default TCP sockets are created active; to create a passive - socket the <a class="Xr">listen(2)</a> system call must be used after - binding the socket with the <a class="Xr">bind(2)</a> system call. Only - passive sockets may use the <a class="Xr">accept(2)</a> call to accept - incoming connections. Only active sockets may use the - <a class="Xr">connect(2)</a> call to initiate connections.</p> -<p class="Pp">Passive sockets may “underspecify” their location to - match incoming connection requests from multiple networks. This technique, - termed “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 - <code class="Dv">INADDR_ANY</code> must be bound. The 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.</p> -<p class="Pp">TCP supports a number of socket options which can be set with - <a class="Xr">setsockopt(2)</a> and tested with - <a class="Xr">getsockopt(2)</a>:</p> -<dl class="Bl-tag"> - <dt id="TCP_NODELAY"><a class="permalink" href="#TCP_NODELAY"><code class="Dv">TCP_NODELAY</code></a></dt> - <dd>Under most circumstances, 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 acknowledgment 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, TCP provides a boolean option, - <code class="Dv">TCP_NODELAY</code> (from - <code class="In"><<a class="In">netinet/tcp.h</a>></code>, to defeat - this algorithm.</dd> - <dt id="TCP_MAXSEG"><a class="permalink" href="#TCP_MAXSEG"><code class="Dv">TCP_MAXSEG</code></a></dt> - <dd>By default, a sender- and receiver-TCP will negotiate among themselves to - determine the maximum segment size to be used for each connection. The - <code class="Dv">TCP_MAXSEG</code> option allows the user to determine the - result of this negotiation, and to reduce it if desired.</dd> - <dt id="TCP_MD5SIG"><a class="permalink" href="#TCP_MD5SIG"><code class="Dv">TCP_MD5SIG</code></a></dt> - <dd>This option enables the use of MD5 digests (also known as TCP-MD5) on - writes to the specified socket. In the current release, only outgoing - traffic is digested; digests on incoming traffic are not verified. The - current default behavior for the system is to respond to a system - advertising this option with TCP-MD5; this may change. - <p class="Pp">One common use for this in a <span class="Ux">NetBSD</span> - router deployment is to enable based routers to interwork with Cisco - equipment at peering points. Support for this feature conforms to RFC - 2385. Only IPv4 (AF_INET) sessions are supported.</p> - <p class="Pp">In order for this option to function correctly, it is - necessary for the administrator to add a tcp-md5 key entry to the - system's security associations database (SADB) using the - <a class="Xr">setkey(8)</a> utility. This entry must have an SPI of - 0x1000 and can therefore only be specified on a per-host basis at this - time.</p> - <p class="Pp" id="tcp_signature_compute:">If an SADB entry cannot be found - for the destination, the outgoing traffic will have an invalid digest - option prepended, and the following error message will be visible on the - system console: - <a class="permalink" href="#tcp_signature_compute:"><i class="Em">tcp_signature_compute: - SADB lookup failed for %d.%d.%d.%d</i></a>.</p> - </dd> - <dt id="TCP_KEEPIDLE"><a class="permalink" href="#TCP_KEEPIDLE"><code class="Dv">TCP_KEEPIDLE</code></a></dt> - <dd>TCP probes a connection that has been idle for some amount of time. The - default value for this idle period is 4 hours. The - <code class="Dv">TCP_KEEPIDLE</code> option can be used to affect this - value for a given socket, and specifies the number of seconds of idle time - between keepalive probes. This option takes an <var class="Vt">unsigned - int</var> value, with a value greater than 0.</dd> - <dt id="TCP_KEEPINTVL"><a class="permalink" href="#TCP_KEEPINTVL"><code class="Dv">TCP_KEEPINTVL</code></a></dt> - <dd>When the <code class="Dv">SO_KEEPALIVE</code> option is enabled, TCP - probes a connection that has been idle for some amount of time. If the - remote system does not respond to a keepalive probe, TCP retransmits the - probe after some amount of time. The default value for this retransmit - interval is 150 seconds. The <code class="Dv">TCP_KEEPINTVL</code> option - can be used to affect this value for a given socket, and specifies the - number of seconds to wait before retransmitting a keepalive probe. This - option takes an <var class="Vt">unsigned int</var> value, with a value - greater than 0.</dd> - <dt id="TCP_KEEPCNT"><a class="permalink" href="#TCP_KEEPCNT"><code class="Dv">TCP_KEEPCNT</code></a></dt> - <dd>When the <code class="Dv">SO_KEEPALIVE</code> option is enabled, TCP - probes a connection that has been idle for some amount of time. If the - remote system does not respond to a keepalive probe, TCP retransmits the - probe a certain number of times before a connection is considered to be - broken. The default value for this keepalive probe retransmit limit is 8. - The <code class="Dv">TCP_KEEPCNT</code> option can be used to affect this - value for a given socket, and specifies the maximum number of keepalive - probes to be sent. This option takes an <var class="Vt">unsigned int</var> - value, with a value greater than 0.</dd> - <dt id="TCP_KEEPINIT"><a class="permalink" href="#TCP_KEEPINIT"><code class="Dv">TCP_KEEPINIT</code></a></dt> - <dd>If a TCP connection cannot be established within some amount of time, TCP - will time out the connect attempt. The default value for this initial - connection establishment timeout is 150 seconds. The - <code class="Dv">TCP_KEEPINIT</code> option can be used to affect this - initial timeout period for a given socket, and specifies the number of - seconds to wait before the connect attempt is timed out. For passive - connections, the <code class="Dv">TCP_KEEPINIT</code> option value is - inherited from the listening socket. This option takes an - <var class="Vt">unsigned int</var> value, with a value greater than - 0.</dd> - <dt id="TCP_INFO"><a class="permalink" href="#TCP_INFO"><code class="Dv">TCP_INFO</code></a></dt> - <dd>Information about a socket's underlying TCP session may be retrieved by - passing the read-only option <code class="Dv">TPC_INFO</code> to - <a class="Xr">getsockopt(2)</a>. It accepts a single argument: a pointer - to an instance of <var class="Vt">struct tcp_info</var>. - <p class="Pp">This API is subject to change; consult the source to determine - which fields are currently filled out by this option. - <span class="Ux">NetBSD</span> specific additions include send window - size, receive window size, and bandwidth-controlled window space.</p> - </dd> -</dl> -<p class="Pp">The option level for the <a class="Xr">setsockopt(2)</a> call is - the protocol number for TCP, available from - <a class="Xr">getprotobyname(3)</a>.</p> -<p class="Pp">In the historical <span class="Ux">BSD</span> TCP implementation, - if the <code class="Dv">TCP_NODELAY</code> option was set on a passive - socket, the sockets returned by <a class="Xr">accept(2)</a> erroneously did - not have the <code class="Dv">TCP_NODELAY</code> option set; the behavior - was corrected to inherit <code class="Dv">TCP_NODELAY</code> in - <span class="Ux">NetBSD 1.6</span>.</p> -<p class="Pp">Options at the IP network level may be used with TCP; see - <a class="Xr">ip(4)</a> or <a class="Xr">ip6(4)</a>. Incoming connection - requests that are source-routed are noted, and the reverse source route is - used in responding.</p> -<p class="Pp">There are many adjustable parameters that control various aspects - of the <span class="Ux">NetBSD</span> TCP behavior; these parameters are - documented in <a class="Xr">sysctl(7)</a>, and they include:</p> -<ul class="Bl-bullet Bl-compact"> - <li>RFC 1323 extensions for high performance</li> - <li>Send/receive buffer sizes</li> - <li>Default maximum segment size (MSS)</li> - <li>SYN cache parameters</li> - <li>Hughes/Touch/Heidemann Congestion Window Monitoring algorithm</li> - <li>Keepalive parameters</li> - <li>newReno algorithm for congestion control</li> - <li>Logging of connection refusals</li> - <li>RST packet rate limits</li> - <li>SACK (Selective Acknowledgment)</li> - <li>ECN (Explicit Congestion Notification)</li> - <li>Congestion window increase methods; the traditional packet counting or RFC - 3465 Appropriate Byte Counting</li> - <li>RFC 3390: Increased initial window size</li> -</ul> -</section> -<section class="Sh"> -<h1 class="Sh" id="DIAGNOSTICS"><a class="permalink" href="#DIAGNOSTICS">DIAGNOSTICS</a></h1> -<p class="Pp">A socket operation may fail with one of the following errors - returned:</p> -<dl class="Bl-tag"> - <dt>[<code class="Er">EISCONN</code>]</dt> - <dd>when trying to establish a connection on a socket which already has - one;</dd> - <dt>[<code class="Er">ENOBUFS</code>]</dt> - <dd>when the system runs out of memory for an internal data structure;</dd> - <dt>[<code class="Er">ETIMEDOUT</code>]</dt> - <dd>when a connection was dropped due to excessive retransmissions;</dd> - <dt>[<code class="Er">ECONNRESET</code>]</dt> - <dd>when the remote peer forces the connection to be closed;</dd> - <dt>[<code class="Er">ECONNREFUSED</code>]</dt> - <dd>when the remote peer actively refuses connection establishment (usually - because no process is listening to the port);</dd> - <dt>[<code class="Er">EADDRINUSE</code>]</dt> - <dd>when an attempt is made to create a socket with a port which has already - been allocated;</dd> - <dt>[<code class="Er">EADDRNOTAVAIL</code>]</dt> - <dd>when an attempt is made to create a socket with a network address for - which no network interface exists.</dd> -</dl> -</section> -<section class="Sh"> -<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE - ALSO</a></h1> -<p class="Pp"><a class="Xr">getsockopt(2)</a>, <a class="Xr">socket(2)</a>, - <a class="Xr">inet(4)</a>, <a class="Xr">inet6(4)</a>, - <a class="Xr">intro(4)</a>, <a class="Xr">ip(4)</a>, - <a class="Xr">ip6(4)</a>, <a class="Xr">sysctl(7)</a></p> -<p class="Pp"><cite class="Rs"><span class="RsT">Transmission Control - Protocol</span>, <span class="RsR">RFC</span>, <span class="RsN">793</span>, - <span class="RsD">September 1981</span>.</cite></p> -<p class="Pp"><cite class="Rs"><span class="RsT">Requirements for Internet Hosts - -- Communication Layers</span>, <span class="RsR">RFC</span>, - <span class="RsN">1122</span>, <span class="RsD">October - 1989</span>.</cite></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1> -<p class="Pp">The <code class="Nm">tcp</code> protocol stack appeared in - <span class="Ux">4.2BSD</span>.</p> -</section> -</div> -<table class="foot"> - <tr> - <td class="foot-date">February 14, 2015</td> - <td class="foot-os">NetBSD 10.1</td> - </tr> -</table> |