nixpkgs/lib/qemu-flags.nix

# QEMU flags shared between various Nix expressions.

{

  qemuNICFlags = nic: net: machine:
    "-net nic,vlan=${toString nic},macaddr=52:54:00:12:${toString net}:${toString machine},model=virtio " +
    "-net vde,vlan=${toString nic},sock=$QEMU_VDE_SOCKET_${toString net} ";

}
* The installer test lost the QEMU flags to set up the NIC to talk to the web server somewhere, so put them back in (http://hydra.nixos.org/build/424923). svn path=/nixos/trunk/; revision=22003 2010-05-27 12:20:37 +00:00			`# QEMU flags shared between various Nix expressions.`

			`{`

* ZOMG, fixed a giant bug in the networking of distributed VM tests. It turns out that all network interfaces in all VMs had the same Ethernet address (52:54:00:12:34:56) because we didn't specify any with the macaddr=... option. This can obviously lead to great confusion. For instance, when a router forwards a packet, it can actually end up sending the packet to itself because the target machine has the same Ethernet address (causing a loop until the TTL expires), while the target also receives the packet. It's amazing anything worked at all, really. So now we just set the Ethernet addresses to 52:54:00:12:<virtual network number>:<machine number>. svn path=/nixos/trunk/; revision=25020 2010-12-07 00:44:29 +00:00			`qemuNICFlags = nic: net: machine:`
			`"-net nic,vlan=${toString nic},macaddr=52:54:00:12:${toString net}:${toString machine},model=virtio " +`
* Use vde_switch instead of QEMU's multicast feature to tie QEMU VMs together into virtual networks. This has several advantages: - It's more secure because the QEMU instances use Unix domain sockets to talk to the switch. - It doesn't depend on the host's network interfaces. (Local multicast fails if there is no default gateway, so for instance it fails if a laptop is not connected to any network.) - VDE devices can be connected together to form arbitrary network topologies. - VDE has a "wirefilter" tool to emulate delays and packet loss, which are useful for network testing. svn path=/nixos/trunk/; revision=25526 2011-01-12 18:47:23 +00:00			`"-net vde,vlan=${toString nic},sock=$QEMU_VDE_SOCKET_${toString net} ";`

* The installer test lost the QEMU flags to set up the NIC to talk to the web server somewhere, so put them back in (http://hydra.nixos.org/build/424923). svn path=/nixos/trunk/; revision=22003 2010-05-27 12:20:37 +00:00			`}`