zebra: include MTU option in RA on request (BZ#665)
This implements a new "ipv6 nd mtu <1-65535>" interface-level command.
* doc/ipv6.texi: add description
* zebra/rtadv.c
* rtadv_send_packet(): send option type 5, when configured
* ipv6_nd_mtu(): new VTY helper
* no_ipv6_nd_mtu(): ditto
* rtadv_config_write(): add new option
* rtadv_init(): list new helpers
diff --git a/doc/ipv6.texi b/doc/ipv6.texi
index a78a92f..ff07dfb 100644
--- a/doc/ipv6.texi
+++ b/doc/ipv6.texi
@@ -157,6 +157,15 @@
Default: medium
@end deffn
+@deffn {Interface Command} {ipv6 nd mtu <1-65535>} {}
+@deffnx {Interface Command} {no ipv6 nd mtu [<1-65535>]} {}
+Include an MTU (type 5) option in each RA packet to assist the attached hosts
+in proper interface configuration. The announced value is not verified to be
+consistent with router interface MTU.
+
+Default: don't advertise any MTU option
+@end deffn
+
@example
@group
interface eth0