sync with latest kame tree.

- reduce chances for signal handler rae condition
- decrease chances for misconfiguration
- feedbacks from router renumbering protocol bakeoff
- cleanups related to mtu handling

1 files changed, 41 insertions, 18 deletions

diff --git a/usr.sbin/rtadvd/rtadvd.8 b/usr.sbin/rtadvd/rtadvd.8
index 13cb1d4463d..58e40c21f06 100644
--- a/usr.sbin/rtadvd/rtadvd.8
+++ b/usr.sbin/rtadvd/rtadvd.8
@@ -1,5 +1,5 @@
-.\"	$OpenBSD: rtadvd.8,v 1.12 2000/07/06 10:14:47 itojun Exp $
-.\"	$KAME: rtadvd.8,v 1.9 2000/05/27 13:37:01 jinmei Exp $
+.\"	$OpenBSD: rtadvd.8,v 1.13 2001/01/15 11:06:28 itojun Exp $
+.\"	$KAME: rtadvd.8,v 1.15 2000/12/22 08:54:29 jinmei Exp $
 .\"
 .\" Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 .\" All rights reserved.
@@ -41,18 +41,18 @@
 .Ar interface ...
 .Sh DESCRIPTION
 .Nm
-advertises router advertisement packet to the specified
+sends router advertisement packets to the specified
 .Ar interfaces .
 .Pp
 The program will daemonize itself on invocation.
-It will then periodically send router advertisement packets, as well
+It will then send router advertisement packets periodically, as well
 as in response to router solicitation messages sent by end hosts.
 .Pp
 Router advertisements can be configured on a per-interface basis, as
 described in
 .Xr rtadvd.conf 5 .
 .Pp
-In the event of no configuration file entry for an interface,
+If there is no configuration file entry for an interface,
 or if the configuration file does not exist altogether,
 .Nm
 sets all the parameters to their default values.
@@ -70,13 +70,22 @@ specified by the configuration file,
 adds/deletes the corresponding prefix to/from its advertising list,
 respectively.
 The
-.Ic Fl s
-may be used to disable this behavior.
+.Fl s
+option may be used to disable this behavior.
 Moreover, if the status of an advertising interface changes,
 .Nm
 will start or stop sending router advertisements according
 to the latest status.
 .Pp
+Basically, hosts MUST NOT send Router Advertisement messages at any
+time (RFC 2461, Section 6.2.3).
+However, it would sometimes be useful to allow hosts to advertise some
+parameters such as prefix information and link MTU.
+Thus,
+.Nm
+can be invoked if router lifetime is explicitly set zero on every
+advertising interface.
+.Pp
 The command line options are:
 .Bl -tag -width indent
 .\"
@@ -93,6 +102,15 @@ Print debugging information.
 Even more debugging information is printed.
 .It Fl f
 Foreground mode (useful when debugging).
+.It Fl M
+Specify an interface to join the all-routers site-local multicast group.
+By default,
+.Nm
+tries to join the first advertising interface appeared in the command
+line.
+This option has meaning only with the
+.Fl R
+option, which enables auto routing renumbering.
 .\".It Fl m
 .\"Enables mobile IPv6 support.
 .\"This changes the content of router advertisement option, as well as
@@ -109,7 +127,7 @@ Upon receipt of signal
 .Dv SIGUSR1 ,
 .Nm
 will dump the current internal state into
-.Pa /var/run/rtadvd.dump.
+.Pa /var/run/rtadvd.dump .
 .Pp
 Use
 .Dv SIGTERM
@@ -120,18 +138,20 @@ In this case,
 .Nm
 will transmit router advertisement with router lifetime 0
 to all the interfaces
-.Pq according to RFC2461 6.2.5 .
+.Pq in accordance with RFC2461 6.2.5 .
 .Sh RETURN VALUES
-The program exits with 0 on success, and non-zero on failures.
+The
+.Nm
+program exits 0 on success, and >0 on failures.
 .Sh FILES
-.Bl -tag -width /etc/rtadvd.conf -compact
+.Bl -tag -width Pa -compact
 .It Pa /etc/rtadvd.conf
 The default configuration file.
 .It Pa /var/run/rtadvd.pid
-contains pid of the currently running
+contains the pid of the currently running
 .Nm rtadvd .
 .It Pa /var/run/rtadvd.dump
-on which
+in which
 .Nm
 dumps its internal state.
 .El
@@ -144,9 +164,12 @@ The
 .Nm
 command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
 .Sh CAVEAT
-Router advertisements should only be performed downstream.
-Erroneous upstream advertisements will cause
+There used to be some text that recommended users not to let
+.Nm
+advertise Router Advertisement messages on an upstream link to avoid
+undesirable
 .Xr icmp6 4
-redirect packet storms in the subnet, as (per the specification) the
-advertising router is assumed to become the default router for
-end hosts in the subnet.
+redirect messages.
+However, based on the later discussion in the IETF ipng working group,
+all routers should rather advertise the messages regardless of
+the network topology, in order to ensure reachability.