OPNsense Forum

Good morning,

My ISP required to send IGMPv2 frame to have IPTV. I tried to change the tunable "net.inet.igmp.default_version" to 2 and it is not working.

After some investigation I found that there is a commit in the main branch of FreeBSD https://github.com/freebsd/freebsd-src/commit/b94ec00ba73ef4769f62555bfcb840919143e198 to prevent fallback to IGMPv3 when "net.inet.igmp.default_version" is set to 2. Then I follow the guide which explains how to compile OPNSense, I compiled a custom kernel with the commit and I made also a change in igmp.c to initialise the interface with version 2
VNET_DEFINE_STATIC(int, igmp_default_version) = IGMP_VERSION_2;
To solve my problem, I have the following options :

• Compile a custom kernel for each OPNSense release
• Wait until the commit and other correction are included in OPNSense
• Wait until the commit is included in OPNSense then just have to send only IGMPv2 frame to always stay is version 2
• Use a trick to send an IGMPv2 frame through the WAN interface, like that FreeBSD switch back to IGMPv2 but I have to do it regulary since FreeBSD will fallback to IGMPv3. (It is the solution used buy other using the same ISP than mine)

My preference will go to option 2, however I have no idea if there are any side effect on additional code I have added to be sure that IGMPv2 will be used as soon as the interface is up. And I have not competencies to propose a code modification to initialise the IGMP version with the value stored in "net.inet.igmp.default_version".


Question 1 : In the OPNSense roadmap, is there any chance that IGMP will be updated soon to consider the "default_version" settings ?
Question 2 : Is there a trick to compile only the igmp part without recompiling the complete kernel ?

If you have other idea, do not hesitate to share.

Olivier

I suggest opening an issue on github for option #2.

Have you tried the os-igmp-proxy plugin?

It does send an IGMP V2 General query packet on the selected Downstream interface.

Regards 

I have not indicated but yes, I use the os-igmp-proxy plugin. It is configurated to have LAN as downstream interface and WAN as upstream. In the option #4, IPTV is working correctly so it is not an issue with igmpproxy.

According information I have retrieved, the plugin is based igmpproxy from pali: https://github.com/pali/igmpproxy. However igmpproxy does not send directly the IGMP frame itself but rely on the kernel itself through the "IP_ADD_MEMBERSHIP" like for example in the following code https://github.com/pali/igmpproxy/blob/master/src/kern.c#L132