.\"	$KAME: rtsold.8,v 1.20 2003/04/11 12:46:12 jinmei Exp $
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.\" $FreeBSD$
.\"
.Dd May 2, 2023
.Dt RTSOLD 8
.Os
.\"
.Sh NAME
.Nm rtsold , rtsol
.Nd router solicitation daemon
.\"
.Sh SYNOPSIS
.Nm
.Op Fl dDfFimu1
.Op Fl M Ar script-name
.Op Fl O Ar script-name
.Op Fl A Ar script-name
.Op Fl p Ar pidfile
.Op Fl R Ar script-name
.Ar interface ...
.Nm
.Op Fl dDfFimu1
.Op Fl M Ar script-name
.Op Fl O Ar script-name
.Op Fl A Ar script-name
.Op Fl p Ar pidfile
.Op Fl R Ar script-name
.Fl a
.Nm rtsol
.Op Fl dDiu
.Op Fl M Ar script-name
.Op Fl O Ar script-name
.Op Fl A Ar script-name
.Op Fl R Ar script-name
.Ar interface ...
.Nm rtsol
.Op Fl dDiu
.Op Fl M Ar script-name
.Op Fl O Ar script-name
.Op Fl A Ar script-name
.Op Fl R Ar script-name
.Fl a
.\"
.Sh DESCRIPTION
.Nm
is the daemon program to send ICMPv6 Router Solicitation messages
on the specified interfaces.
If a node (re)attaches to a link,
.Nm
sends some Router Solicitations on the link destined to the link-local scope
all-routers multicast address to discover new routers
and to get non link-local addresses.
.Pp
.Nm
should be used on IPv6 hosts
.Pq non-router nodes
only.
.Pp
If you invoke the program as
.Nm rtsol ,
it will transmit probes from the specified
.Ar interface ,
without becoming a daemon.
In other words,
.Nm rtsol
behaves as
.Do
.Nm
.Fl f1
.Ar interfaces
.Dc .
.Pp
Specifically,
.Nm
sends at most 3 Router Solicitations on an interface
after one of the following events:
.Pp
.Bl -bullet -compact
.It
Just after invocation of
.Nm
daemon.
.It
The interface is up after a temporary interface failure.
.Nm
detects such failures by periodically probing to see if the status
of the interface is active or not.
Note that some network cards and drivers do not allow the extraction
of link state.
In such cases,
.Nm
cannot detect the change of the interface status.
.It
Every 60 seconds if the
.Fl m
option is specified and the
.Nm
daemon cannot get the interface status.
This feature does not conform to the IPv6 neighbor discovery
specification, but is provided for mobile stations.
The default interval for router advertisements, which is on the order of 10
minutes, is slightly long for mobile stations.
This feature is provided
for such stations so that they can find new routers as soon as possible
when they attach to another link.
.El
.Lp
Once
.Nm
has sent a Router Solicitation, and has received a valid Router Advertisement,
it refrains from sending additional solicitations on that interface, until
the next time one of the above events occurs.
.Lp
When sending a Router Solicitation on an interface,
.Nm
includes a Source Link-layer address option if the interface
has a link-layer address.
.Lp
.Nm
manages a per-interface parameter to detect if a separate protocol is
needed for configuration parameters other than host's addresses.
At the invocation time, the flag is FALSE, and becomes TRUE when
the daemon receives a router advertisement with the OtherConfig flag
being set.
A script file can be specified to deal with the case
.Pq see below .
When
.Nm
start resending router solicitation messages by one of the conditions
events,
the daemon resets the parameter because the event may indicate a
change on the attached link.
.Pp
Upon receipt of signal
.Dv SIGUSR1 ,
.Nm
will dump the current internal state into
.Pa /var/run/rtsold.dump .
.\"
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl a
Autoprobe outgoing interfaces.
.Nm
will try to find any non-loopback, IPv6-capable interfaces
and send router solicitation messages on all of them.
.It Fl d
Enable debugging.
.It Fl D
Enable more debugging including the printing of internal timer information.
.It Fl f
Prevent
.Nm
from becoming a daemon (foreground mode).
Warning messages are generated to standard error
instead of
.Xr syslog 3 .
.It Fl F
Explicitly configure the kernel to accept Router Advertisements and
disable IPv6 forwarding.
These settings are required for proper
.Nm
operation.
Without this option, the current settings will be obeyed;
if they are incompatible with proper operation,
warning messages will be generated,
but Router Solicitations will still be sent.
The settings may be changed manually with
.Xr sysctl 8
and
.Xr ifconfig 8 .
.It Fl i
Transmit Router Solicitation packets immediately, without waiting the
normal random (between 0 and 1 second) delay.
This option should not be used on networks where it might result in
congestion due to many hosts simultaneously (re)connecting and
sending such packets.
.It Fl m
Enable mobility support.
If this option is specified,
.Nm
sends probing packets to default routers that have advertised Router
Advertisements
when the node (re)attaches to an interface.
Moreover, if the option is specified,
.Nm
periodically sends Router Solicitation on an interface that does not support
.Dv SIOCGIFMEDIA
ioctl.
.It Fl 1
Perform only one probe.
Transmit Router Solicitation packets until at least one valid Router
Advertisement packet has arrived on each
.Ar interface ,
then exit.
.It Fl M Ar script-name
Specifies a supplement script file to handle the Managed Configuration
flag of the router advertisement.
When the flag changes from FALSE to TRUE,
.Nm
will invoke
.Ar script-name
with a first argument of the receiving interface name
and a second argument of the sending router address,
expecting the script will then start a protocol for the managed
configuration.
.Ar script-name
must be the absolute path from root to the script file, be a regular
file, and be created by the same owner who runs
.Nm .
.It Fl O Ar script-name
Specifies a supplement script file to handle the Other Configuration
flag of the router advertisement.
When the flag changes from FALSE to TRUE,
.Nm
will invoke
.Ar script-name
with a first argument of the receiving interface name
and a second argument of the sending router address,
expecting the script will then start a protocol for the other
configuration.
The script will not be run if the Managed Configuration flag in the
router advertisement is also TRUE.
.Ar script-name
must be the absolute path from root to the script file, be a regular
file, and be created by the same owner who runs
.Nm .
.It Fl A Ar script-name
Specifies a supplement script file to always be called for the router
advertisement.
.Nm
will invoke
.Ar script-name
with a first argument of the receiving interface name
and a second argument of the sending router address.
.Ar script-name
must be the absolute path from root to the script file, be a regular
file, and be created by the same owner who runs
.Nm .
.It Fl p Ar pidfile
Writes the process ID of
.Nm
to
.Pa pidfile
instead of the default PID file
.Pa /var/run/rtsold.pid .
.It Fl R Ar script-name
Specifies a script to run when router advertisement options
.Dv RDNSS Pq Recursive DNS Server
or
.Dv DNSSL Pq DNS Search List
are encountered.
The information of DNS servers and DNS search domains will be sent to
standard input of this script.
The
.Xr resolvconf 8
script is used by default.
.It Fl u
Specifies whether to add the source address of Router Advertisement
messages to the interface name in the parameters of the RDNSS and DNSSL
scripts.
.Pp
If
.Fl u
is specified, the interface name in the script parameters will be
.Ql ifname:slaac:[RA-source-address] .
.Pp
Otherwise it will be
.Ql ifname:slaac .
.El
.Sh FILES
.Bl -tag -width /var/run/rtsold.dump -compact
.It Pa /var/run/rtsold.pid
The PID of the currently running
.Nm .
.It Pa /var/run/rtsold.dump
Internal state dump file.
.El
.\"
.Sh EXIT STATUS
.Ex -std
.\"
.Sh SEE ALSO
.Xr resolvconf 8 ,
.Xr rtadvd 8 ,
.Xr sysctl 8
.\"
.Sh HISTORY
The
.Nm
command is based on the
.Nm rtsol
command, which first appeared in WIDE/KAME IPv6 protocol stack kit.
.Nm rtsol
is now integrated into
.Xr rtsold 8 .
.\"
.Sh BUGS
When a network card is removed and reinserted, the corresponding interface index
may change.
However,
.Nm
assumes such changes will not occur, and always uses the index that
it got at invocation.
As a result,
.Nm
may not work if you reinsert a network card.
In such a case,
.Nm
should be killed and restarted.
.Pp
The IPv6 autoconfiguration specification assumes a single-interface host.
You may see kernel error messages if you try to autoconfigure a host with
multiple interfaces.
Also, it seems contradictory for
.Nm
to accept multiple
.Ar interface
arguments.