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<table class="head">
<tr>
<td class="head-ltitle">PIM(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">PIM(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">pim</code> — <span class="Nd">Protocol
Independent Multicast</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">options MROUTING</code></p>
<p class="Pp">
<br/>
<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>
<br/>
<code class="In">#include <<a class="In">netinet/ip_mroute.h</a>></code>
<br/>
<code class="In">#include <<a class="In">netinet/pim.h</a>></code></p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">getsockopt</code>(<var class="Fa" style="white-space: nowrap;">int
s</var>, <var class="Fa" style="white-space: nowrap;">IPPROTO_IP</var>,
<var class="Fa" style="white-space: nowrap;">MRT_PIM</var>,
<var class="Fa" style="white-space: nowrap;">void *optval</var>,
<var class="Fa" style="white-space: nowrap;">socklen_t *optlen</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">setsockopt</code>(<var class="Fa" style="white-space: nowrap;">int
s</var>, <var class="Fa" style="white-space: nowrap;">IPPROTO_IP</var>,
<var class="Fa" style="white-space: nowrap;">MRT_PIM</var>,
<var class="Fa" style="white-space: nowrap;">const void *optval</var>,
<var class="Fa" style="white-space: nowrap;">socklen_t optlen</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">getsockopt</code>(<var class="Fa" style="white-space: nowrap;">int
s</var>, <var class="Fa" style="white-space: nowrap;">IPPROTO_IPV6</var>,
<var class="Fa" style="white-space: nowrap;">MRT6_PIM</var>,
<var class="Fa" style="white-space: nowrap;">void *optval</var>,
<var class="Fa" style="white-space: nowrap;">socklen_t *optlen</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">setsockopt</code>(<var class="Fa" style="white-space: nowrap;">int
s</var>, <var class="Fa" style="white-space: nowrap;">IPPROTO_IPV6</var>,
<var class="Fa" style="white-space: nowrap;">MRT6_PIM</var>,
<var class="Fa" style="white-space: nowrap;">const void *optval</var>,
<var class="Fa" style="white-space: nowrap;">socklen_t optlen</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">PIM is the common name for two multicast routing protocols:
Protocol Independent Multicast - Sparse Mode (PIM-SM) and Protocol
Independent Multicast - Dense Mode (PIM-DM).</p>
<p class="Pp">PIM-SM is a multicast routing protocol that can use the underlying
unicast routing information base or a separate multicast-capable routing
information base. It builds unidirectional shared trees rooted at a
Rendezvous Point (RP) per group, and optionally creates shortest-path trees
per source.</p>
<p class="Pp">PIM-DM is a multicast routing protocol that uses the underlying
unicast routing information base to flood multicast datagrams to all
multicast routers. Prune messages are used to prevent future datagrams from
propagating to routers with no group membership information.</p>
<p class="Pp">Both PIM-SM and PIM-DM are fairly complex protocols, though PIM-SM
is much more complex. To enable PIM-SM or PIM-DM multicast routing in a
router, the user must enable multicast routing and PIM processing in the
kernel (see <a class="Sx" href="#SYNOPSIS">SYNOPSIS</a> about the kernel
configuration options), and must run a PIM-SM or PIM-DM capable user-level
process. From developer's point of view, the programming guide described in
the <a class="Sx" href="#Programming_Guide">Programming Guide</a> section
should be used to control the PIM processing in the kernel.</p>
<section class="Ss">
<h2 class="Ss" id="Programming_Guide"><a class="permalink" href="#Programming_Guide">Programming
Guide</a></h2>
<p class="Pp">After a multicast routing socket is open and multicast forwarding
is enabled in the kernel (see <a class="Xr">multicast(4)</a>), one of the
following socket options should be used to enable or disable PIM processing
in the kernel. Note that those options require certain privilege (i.e., root
privilege):</p>
<div class="Bd Pp Li">
<pre>/* IPv4 */
int v = 1; /* 1 to enable, or 0 to disable */
setsockopt(mrouter_s4, IPPROTO_IP, MRT_PIM, (void *)&v, sizeof(v));</pre>
</div>
<div class="Bd Pp Li">
<pre>/* IPv6 */
int v = 1; /* 1 to enable, or 0 to disable */
setsockopt(mrouter_s6, IPPROTO_IPV6, MRT6_PIM, (void *)&v, sizeof(v));</pre>
</div>
<p class="Pp">After PIM processing is enabled, the multicast-capable interfaces
should be added (see <a class="Xr">multicast(4)</a>). In case of PIM-SM, the
PIM-Register virtual interface must be added as well. This can be
accomplished by using the following options:</p>
<div class="Bd Pp Li">
<pre>/* IPv4 */
struct vifctl vc;
memset(&vc, 0, sizeof(vc));
/* Assign all vifctl fields as appropriate */
...
if (is_pim_register_vif)
vc.vifc_flags |= VIFF_REGISTER;
setsockopt(mrouter_s4, IPPROTO_IP, MRT_ADD_VIF, (void *)&vc,
sizeof(vc));</pre>
</div>
<div class="Bd Pp Li">
<pre>/* IPv6 */
struct mif6ctl mc;
memset(&mc, 0, sizeof(mc));
/* Assign all mif6ctl fields as appropriate */
...
if (is_pim_register_vif)
mc.mif6c_flags |= MIFF_REGISTER;
setsockopt(mrouter_s6, IPPROTO_IPV6, MRT6_ADD_MIF, (void *)&mc,
sizeof(mc));</pre>
</div>
<p class="Pp">Sending or receiving of PIM packets can be accomplished by opening
first a “raw socket” (see <a class="Xr">socket(2)</a>), with
protocol value of <code class="Dv">IPPROTO_PIM</code>:</p>
<div class="Bd Pp Li">
<pre>/* IPv4 */
int pim_s4;
pim_s4 = socket(AF_INET, SOCK_RAW, IPPROTO_PIM);</pre>
</div>
<div class="Bd Pp Li">
<pre>/* IPv6 */
int pim_s6;
pim_s6 = socket(AF_INET6, SOCK_RAW, IPPROTO_PIM);</pre>
</div>
<p class="Pp">Then, the following system calls can be used to send or receive
PIM packets: <a class="Xr">sendto(2)</a>, <a class="Xr">sendmsg(2)</a>,
<a class="Xr">recvfrom(2)</a>, <a class="Xr">recvmsg(2)</a>.</p>
</section>
</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">recvfrom(2)</a>,
<a class="Xr">recvmsg(2)</a>, <a class="Xr">sendmsg(2)</a>,
<a class="Xr">sendto(2)</a>, <a class="Xr">setsockopt(2)</a>,
<a class="Xr">socket(2)</a>, <a class="Xr">inet(4)</a>,
<a class="Xr">intro(4)</a>, <a class="Xr">ip(4)</a>,
<a class="Xr">multicast(4)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="STANDARDS"><a class="permalink" href="#STANDARDS">STANDARDS</a></h1>
<p class="Pp">The PIM-SM protocol is specified in RFC 2362 (to be replaced by
<span class="RsT">draft-ietf-pim-sm-v2-new-*).</span> The PIM-DM protocol is
specified in <span class="RsT">draft-ietf-pim-dm-new-v2-*).</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The original IPv4 PIM kernel support for IRIX and SunOS-4.x was
implemented by <span class="An">Ahmed Helmy</span> (USC and SGI). Later the
code was ported to various <span class="Ux">BSD</span> flavors and modified
by <span class="An">George Edmond Eddy</span> (Rusty) (ISI),
<span class="An">Hitoshi Asaeda</span> (WIDE Project), and
<span class="An">Pavlin Radoslavov</span> (USC/ISI and ICSI). The IPv6 PIM
kernel support was implemented by the KAME project
(<span class="Pa">https://www.kame.net</span>), and was based on the IPv4
PIM kernel support.</p>
<p class="Pp">This manual page was written by <span class="An">Pavlin
Radoslavov</span> (ICSI).</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">February 12, 2007</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
