How to send router solicit transaction for ipv6 every few minutes?

Westrem · March 16, 2021, 8:04pm

I'm using starlink. They are currently in beta. Their ipv6 has a bug where they dont send router advertisements unless a router solicitation is requested. Since ipv6 on openwrt only sends out the solicit transaction on first boot, how can I force router solicitation? Someone on reddit fixed the issue in pfsense but I'm not sure how to apply that to openwrt. This was his solution if it helps explain what I need to do. Maybe just a cron job, but not sure what .sh to run.

vgaetera · March 17, 2021, 12:38am

Try these commands:

killall -SIGUSR2 odhcp6c
killall -SIGUSR1 odhcp6c
/etc/init.d/odhcpd reload
/etc/init.d/odhcpd restart
ifup wan6

Westrem · March 17, 2021, 12:41am

So if I ran that every minute, it wouldn't cause issues would it?

vgaetera · March 17, 2021, 12:44am

First test it manually, and if one of the commands works, you can add it to crontab.
Wait up to 10 seconds after each command to be sure it has applied properly.

Westrem · March 17, 2021, 12:45am

Great. Will test it out. Thank you for the suggestions. I will update with the results.

Westrem · March 17, 2021, 10:08pm

None of these seem to do what I am after. Killall restarts the ipv6 network as well as ifup wan6. This does repair the issue when it's down but I can't run it every minute or I lose ipv6 for 10 seconds at a time. The goal is to send router solicitation every minute without disrupting the interface. Someone suggested rtsol and cronjob but I'm not understanding that.

dl12345 · March 17, 2021, 11:08pm

Here you go - a Makefile to compile rdisc6 so you can use the identical solution that was used in the reddit link you posted in your first post.

#
# Copyright (C) 2007-2021 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#

include $(TOPDIR)/rules.mk

PKG_NAME:=ndisc6
PKG_VERSION:=1.0.4
PKG_RELEASE:=1

PKG_SOURCE:=ndisc6-$(PKG_VERSION).tar.bz2
PKG_SOURCE_URL:=https://www.remlab.net/files/ndisc6/
PKG_HASH:=abb1da4a98d94e5abe1dd7b1c975de540306b0581cbbd36aff035118b2f25c1f

PKG_INSTALL:=1
PKG_FIXUP:=autoreconf

include $(INCLUDE_DIR)/package.mk

define Package/ndisc6
  URL:=https://www.remlab.net/ndisc6/
  SECTION:=network
  CATEGORY:=Network
  TITLE:=NDisc6
endef

define Package/ndisc6/description
  NDisc6 is a small collection of useful tools for IPv6 networking
endef

define Package/ndisc6/install
        $(INSTALL_DIR) $(1)/usr/bin
        $(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/ndisc6 $(1)/usr/bin
        $(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/rdisc6 $(1)/usr/bin
endef

$(eval $(call BuildPackage,ndisc6))

dl12345 · March 17, 2021, 11:10pm

Then set it to run with a cron job at whatever frequency you desire

dl12345 · March 17, 2021, 11:12pm

If you can't compile it yourself, send me a link to the exact openwrt image download you're using and I'll compile a binary .ipk for you

Westrem · March 18, 2021, 12:09am

Wow. I appreciate that. I could have swore I was using the latest stable release and just flashed a week ago but it's saying snapshot. I dont understand that, maybe misclick. In any case if you cant compile a binary .ipk for this, just the stable release would work and I can flash the stable version. Or whatever works best. I don't have anything special I need to save in this config. So to make a long story short if you need a stable branch to compile for i will use this one.

http://downloads.openwrt.org/releases/19.07.7/targets/ipq806x/generic/openwrt-19.07.7-ipq806x-generic-netgear_r7800-squashfs-factory.img

Hostname	OpenWrt
Model	Netgear Nighthawk X4S R7800
Architecture	ARMv7 Processor rev 0 (v7l)
Firmware Version	OpenWrt 21.02-SNAPSHOT r15880-e17e212b51 / LuCI openwrt-21.02 branch git-21.060.51546-bd39e6a
Kernel Version	5.4.102

dl12345 · March 18, 2021, 12:47am

Obviously I haven't tested this - your mileage may vary

This is compiled for your current snapshot version - it should work

dl12345 · March 18, 2021, 1:06am

First install it and just run it to see if it installs/works. Then, if it does I can tell you how to add it as a cron job

vgaetera · March 18, 2021, 1:26am

It looks like netifd supports a built-in option:

dl12345 · March 18, 2021, 1:35am

A quick glance at the code of odhcpd seems to show that it only sends a solicit at interface startup. I didn't spend much time looking at the code though

I figured the OP can try the ipk I built first rather than spending a whole lot of time tracing through the code of odhcpd

Westrem · March 18, 2021, 4:05am

it installed fine and ipv6 still works. How would i make the cronjob for it? Thank you.

dl12345 · March 18, 2021, 4:13am

I'm using the command from the reddit post you quoted. Edit the file /etc/crontababs/root

Add the following, changing the eth2 to whatever the physical interface is that is connected to your starlink device.

* * * * * /usr/bin/rdisc6 -q -1 eth2 >& /dev/null

Then restart cron with /etc/init.d/cron restart

Alternatively, go to Luci-->System-->Scheduled Tasks and add the same line. It will add it to the crontab file.

This will run the command every one minute

Westrem · March 18, 2021, 4:25am

ok i set it all up... my physical interface is eth0.2 and that's the only thing i changed in your instructions. ill see if this works. Thank you.

Westrem · March 18, 2021, 4:31am

seems to be working i think

Thu Mar 18 06:27:00 2021 cron.err crond[10310]: USER root pid 12043 cmd /usr/bin/rdisc6 -q -1 eth0.2 >& /dev/null
Thu Mar 18 06:27:51 2021 daemon.notice netifd: wan (1413): udhcpc: sending renew to 100.127.255.3
Thu Mar 18 06:27:51 2021 daemon.notice netifd: wan (1413): udhcpc: lease of 100.77.195.226 obtained, lease time 300
Thu Mar 18 06:27:58 2021 daemon.notice odhcp6c[6825]: Starting RENEW transaction (timeout 45s, max rc 0)
Thu Mar 18 06:27:58 2021 daemon.notice odhcp6c[6825]: Send RENEW message (elapsed 0ms, rc 0)
Thu Mar 18 06:27:58 2021 daemon.notice odhcp6c[6825]: Got a valid REPLY after 31ms
Thu Mar 18 06:27:58 2021 daemon.info odhcp6c[6825]: IA_PD 0001 T1 0 T2 0
Thu Mar 18 06:27:58 2021 daemon.info odhcp6c[6825]: 2605:59c0:52d8:7100::/56 preferred 150 valid 300
Thu Mar 18 06:27:58 2021 daemon.info odhcp6c[6825]: T1 75s, T2 120s, T3 300s
Thu Mar 18 06:27:58 2021 daemon.notice odhcp6c[6825]: Starting <POLL> transaction (timeout 75s, max rc 0)
Thu Mar 18 06:28:00 2021 cron.err crond[10310]: USER root pid 12248 cmd /usr/bin/rdisc6 -q -1 eth0.2 >& /dev/null
Thu Mar 18 06:29:00 2021 cron.err crond[10310]: USER root pid 12270 cmd /usr/bin/rdisc6 -q -1 eth0.2 >& /dev/null
Thu Mar 18 06:29:13 2021 daemon.notice odhcp6c[6825]: Starting RENEW transaction (timeout 45s, max rc 0)
Thu Mar 18 06:29:13 2021 daemon.notice odhcp6c[6825]: Send RENEW message (elapsed 0ms, rc 0)
Thu Mar 18 06:29:13 2021 daemon.notice odhcp6c[6825]: Got a valid REPLY after 40ms
Thu Mar 18 06:29:13 2021 daemon.info odhcp6c[6825]: IA_PD 0001 T1 0 T2 0
Thu Mar 18 06:29:13 2021 daemon.info odhcp6c[6825]: 2605:59c0:52d8:7100::/56 preferred 150 valid 300
Thu Mar 18 06:29:13 2021 daemon.info odhcp6c[6825]: T1 75s, T2 120s, T3 300s
Thu Mar 18 06:29:13 2021 daemon.notice odhcp6c[6825]: Starting <POLL> transaction (timeout 75s, max rc 0)

dl12345 · March 18, 2021, 4:32am

So you mean my work wasn't in vain?

system · March 28, 2021, 4:32am

This topic was automatically closed 10 days after the last reply. New replies are no longer allowed.