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diff --git a/static/freebsd/man4/udp.4 3.html b/static/freebsd/man4/udp.4 3.html new file mode 100644 index 00000000..dfe33785 --- /dev/null +++ b/static/freebsd/man4/udp.4 3.html @@ -0,0 +1,128 @@ +<table class="head"> + <tr> + <td class="head-ltitle">UDP(4)</td> + <td class="head-vol">Device Drivers Manual</td> + <td class="head-rtitle">UDP(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">udp</code> — <span class="Nd">Internet + User Datagram 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/types.h</a>></code> + <br/> + <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_DGRAM</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">UDP is a simple, unreliable datagram protocol which is used to + support the <code class="Dv">SOCK_DGRAM</code> abstraction for the Internet + protocol family. UDP sockets are connectionless, and are normally used with + the <a class="Xr">sendto(2)</a> and <a class="Xr">recvfrom(2)</a> calls, + though the <a class="Xr">connect(2)</a> call may also be used to fix the + destination for future packets (in which case the <a class="Xr">recv(2)</a> + or <a class="Xr">read(2)</a> and <a class="Xr">send(2)</a> or + <a class="Xr">write(2)</a> system calls may be used).</p> +<p class="Pp">UDP address formats are identical to those used by TCP. In + particular UDP provides a port identifier in addition to the normal Internet + address format. Note that the UDP port space is separate from the TCP port + space (i.e., a UDP port may not be “connected” to a TCP port). + In addition broadcast packets may be sent (assuming the underlying network + supports this) by using a reserved “broadcast address”; this + address is network interface dependent.</p> +<p class="Pp">Options at the IP transport level may be used with UDP; see + <a class="Xr">ip(4)</a>. UDP_ENCAP socket option may be used at the + IPPROTO_UDP level to encapsulate ESP packets in UDP. Only one value is + supported for this option: UDP_ENCAP_ESPINUDP from RFC 3948, defined in + <code class="In"><<a class="In">netinet/udp.h</a>></code>.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="FIB_support"><a class="permalink" href="#FIB_support">FIB + support</a></h1> +<p class="Pp">UDP sockets are FIB-aware. They inherit the FIB of the process + which created the socket. By default, a UDP socket bound to an address can + receive datagrams originating from any FIB. If the + <var class="Va">net.inet.udp.bind_all_fibs</var> tunable is set to 0, all + UDP sockets will receive only datagrams originating from the same FIB as the + socket. In this mode, multiple sockets can be bound to the same address, so + long as each socket belongs to a different FIB, similar to the behavior of + the <code class="Dv">SO_REUSEPORT</code> option.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="MIB_(sysctl)_Variables"><a class="permalink" href="#MIB_(sysctl)_Variables">MIB + (sysctl) Variables</a></h1> +<p class="Pp">The <code class="Nm">udp</code> protocol implements a number of + variables in the <var class="Va">net.inet.udp</var> branch of the + <a class="Xr">sysctl(3)</a> MIB, which can be also read or modified with + <a class="Xr">sysctl(8)</a>:</p> +<dl class="Bl-tag"> + <dt id="blackhole"><var class="Va">blackhole</var></dt> + <dd>When a datagram is received on a port where there is no socket listening, + do not return an ICMP port unreachable message. (Disabled by default. See + <a class="Xr">blackhole(4)</a>.)</dd> + <dt id="checksum"><var class="Va">checksum</var></dt> + <dd>Enable UDP checksums (enabled by default).</dd> + <dt id="log_in_vain"><var class="Va">log_in_vain</var></dt> + <dd>For all UDP datagrams, to ports on which there is no socket listening, log + the connection attempt (disabled by default).</dd> + <dt id="maxdgram"><var class="Va">maxdgram</var></dt> + <dd>Maximum outgoing UDP datagram size</dd> + <dt id="recvspace"><var class="Va">recvspace</var></dt> + <dd>Maximum space for incoming UDP datagrams</dd> +</dl> +</section> +<section class="Sh"> +<h1 class="Sh" id="ERRORS"><a class="permalink" href="#ERRORS">ERRORS</a></h1> +<p class="Pp">A socket operation may fail with one of the following errors + returned:</p> +<dl class="Bl-tag"> + <dt id="EISCONN">[<a class="permalink" href="#EISCONN"><code class="Er">EISCONN</code></a>]</dt> + <dd>when trying to establish a connection on a socket which already has one, + or when trying to send a datagram with the destination address specified + and the socket is already connected;</dd> + <dt id="ENOTCONN">[<a class="permalink" href="#ENOTCONN"><code class="Er">ENOTCONN</code></a>]</dt> + <dd>when trying to send a datagram, but no destination address is specified, + and the socket has not been connected;</dd> + <dt id="ENOBUFS">[<a class="permalink" href="#ENOBUFS"><code class="Er">ENOBUFS</code></a>]</dt> + <dd>when the system runs out of memory for an internal data structure;</dd> + <dt id="EADDRINUSE">[<a class="permalink" href="#EADDRINUSE"><code class="Er">EADDRINUSE</code></a>]</dt> + <dd>when an attempt is made to create a socket with a port which has already + been allocated;</dd> + <dt id="EADDRNOTAVAIL">[<a class="permalink" href="#EADDRNOTAVAIL"><code class="Er">EADDRNOTAVAIL</code></a>]</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">recv(2)</a>, + <a class="Xr">send(2)</a>, <a class="Xr">socket(2)</a>, + <a class="Xr">blackhole(4)</a>, <a class="Xr">inet(4)</a>, + <a class="Xr">intro(4)</a>, <a class="Xr">ip(4)</a>, + <a class="Xr">udplite(4)</a></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">udp</code> protocol appeared in + <span class="Ux">4.2BSD</span>.</p> +</section> +</div> +<table class="foot"> + <tr> + <td class="foot-date">January 20, 2025</td> + <td class="foot-os">FreeBSD 15.0</td> + </tr> +</table> |