[Qemu-devel] [PATCH] QEMU multicast socket support v4 (UML mcast compatible)

[JuanJo Ciarlante]

Hi!

Attached patch (against qemu CVS 2005-12-10) adds multicast support for 
QEMU socket transport, ie: run several stateless possibly non-local QEMUs 
on same virtual ethernet "BUS". 
User-mode-linux (UML) compatible (tested).

An excerpt from qemu-doc.texi:

  `-net socket[,vlan=n][,fd=h][,mcast=maddr:port]'
        Create a VLAN n shared with another QEMU virtual machines using
        a UDP multicast socket, effectively making a bus for every QEMU
        with same multicast address maddr and port. NOTES:
         1. Several QEMU can be running on different hosts and share same
            bus (assuming correct multicast setup for these hosts).
         2. mcast  support  is  compatible with User Mode Linux (argument
            `ethN=mcast'), see http://user-mode-linux.sf.net.
  Example:
        # launch one QEMU instance
        qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net 
socket,mcast=230.0.0.1:1234
        # launch another QEMU instance on same "bus"
        qemu linux.img -net nic,macaddr=52:54:00:12:34:57 -net 
socket,mcast=230.0.0.1:1234
        # launch yet another QEMU instance on same "bus"
        qemu linux.img -net nic,macaddr=52:54:00:12:34:58 -net 
socket,mcast=230.0.0.1:1234
  Example (User Mode Linux compat.):
        # launch QEMU instance (note mcast address selected is UML's default)
        qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net 
socket,mcast=239.192.168.1:1102
        # launch UML
        /path/to/linux ubd0=/path/to/root_fs eth0=mcast

Available under GPLv2 from
  http://www.irrigacion.gov.ar/juanjo/qemu/


Changes
-------
v4 (2005-12-12):
        * Tested mcast user-mode-linux compatibility
        * Minor tweaks

v3 (2005-12-07):
        * correctly close fds if any socket syscall fails (ie. close'em don't 
leak'em ;)

v2 (2005-12-07):
        * 1st public release
        
EnjoY   

-- 
--Juanjo

#  Juan Jose Ciarlante (JuanJo) jjo ;at; mendoza.gov.ar                     #
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qemu-socket_mcast.jjo.v4.diff
Description: Text document