https://github.com/Esdenera/mcast-proxy

Multicast Proxy for OpenBSD
https://github.com/Esdenera/mcast-proxy

igmp mld multicast openbsd proxy

Last synced: 2 months ago
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Multicast Proxy for OpenBSD

• Host: GitHub
• URL: https://github.com/Esdenera/mcast-proxy
• Owner: Esdenera
• License: other
• Created: 2017-06-28T16:05:18.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-03-29T13:06:49.000Z (almost 2 years ago)
• Last Synced: 2024-08-02T15:34:45.219Z (5 months ago)
• Topics: igmp, mld, multicast, openbsd, proxy
• Language: C
• Size: 37.1 KB
• Stars: 15
• Watchers: 4
• Forks: 3
• Open Issues: 11
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

Awesome Lists containing this project

README

        
mcast-proxy

===========

About

-----

This is a new daemon for OpenBSD that fills in a gap in the multicast

protocol support for network edges. More specifically we're talking

about a multicast proxy.

The mcast-proxy is a less featured multicast routing daemon that is

mostly used on equipments that face client networks (end users). It is

mainly used when you don't need a full multicast routing daemon (like

[dvmrpd(8)](http://man.openbsd.org/dvmrpd.8),

[mrouted(8)](http://man.openbsd.org/mrouted.8) or pim),

but you want to use your networks resources efficiently.

This implementation has the following features:

* Support IPv4 (IGMPv1/v2) multicast proxy

* Support IPv6 (MLDv1) multicast proxy

* Privilege dropping (runs as user)

* chroot jailing

The development of this daemon brought improvements to the IPv6

multicast stack, like:

* Initial MP support

  Now IPv6 multicast routing code uses the art routing table to store

  the multicast routes. This also means you can see your multicast

  routes in [route(8)](http://man.openbsd.org/route.8).

* Support multiple rdomains

  The interfaces mif (multicast interface) are now domain specific, so

  you can have mif ids duplicated on different rdomains.

* Fixed a few problems in MLD code that prevented some client/server

  functionality

Notes

-----

* The daemon is not yet pledge()d as there is no support for

  MRT(6)_* setsockopt() calls.

* IPv6 multicast proxy requires an OpenBSD -current, because of

  the recent kernel changes and [netstat(1)](http://man.openbsd.org/netstat.1).

Running mcast-proxy

-------------------

To run multicast routing protocols in your machines you have to configure

the following settings:

* Allow multicast routing:

        rcctl enable multicast

* Allow IGMP packets (IPv4 only):

  To allow IP options you have to configure your PF traffic pass rule to

  accept IP options. Example: change 'pass' to 'pass allow-opts'.

* Add a multicast route (if the default doesn't exist or is not correct)

        route add 224/8 192.168.0.1

        route add ff00::/8 fe80::fce1:baff:fed0:2001%vio1

* In case you are using the default route for multicast you might need

  to specify an alternate multicast source. By default mcast-proxy only

  accepts multicast traffic from the same network of your interface.

  For example em0 has IPv6 address: 2001:db8::100,

  but the multicast traffic comes from 2001:db9::10. The same applies for IPv4.

  The `mcast-proxy.conf`:

        interface em0 {

        	source 2001:db9::/64

        	upstream

        }

Design

------

The daemon code is split in the following file hierarchy:

* [mcast-proxy.c](usr.sbin/mcast-proxy/mcast-proxy.c): all IGMP/MLD related packet parsing

* [mrt.c](usr.sbin/mcast-proxy/mrt.c): the multicast routing table on userland

* [kroute.c](usr.sbin/mcast-proxy/kroute.c): all kernel interactions

* [util.c](usr.sbin/mcast-proxy/util.c): misc functions that did not fit the other files

Further Reading

---------------

* [mcast-proxy.8](mcast-proxy.md)

* [mcast-proxy.conf.5](mcast-proxy.conf.md)

* [License](LICENSE.md)