From 2e15716eead40c5cec0793e677259fd3cd10a4b7 Mon Sep 17 00:00:00 2001
From: Aleksandr O. Levchuk <alevchuk@gmail.com>
Date: Mon, 22 Jun 2009 19:14:30 -0700
Subject: [PATCH] Fix in debian-add_ip.sh config, missing network route

This patch creates a way for containers to connect
to the different private networks that surround them.

I had to make this patch because my Debain containers have to access
multiple networks (192.168.1.0/24, 192.168.3.0/24, etc...).

This patch adds a new routes for each IP. A route points to a
network X when a new IP Y is added. The Network X is implicitly
derived from the IP Y. This is done in a simplified way, but it
will work in most cases. Simply the last byte of X is replaced
with 0, to produce Y.

For example, when you run:

  vzctl set ycao-chemolddb \
    --ipdel all \
    --ipadd 192.168.16.53 \
    --ipadd 192.168.1.53 \
    --save

The resulting Debain /etc/network/interfaces will look like this:

 # This configuration file is auto-generated.
 # WARNING: Do not edit this file, your changes will be lost.
 # Please create/edit /etc/network/interfaces.head and /etc/network/interfaces.tail instead,
 # their contents will be inserted at the beginning and at the end
 # of this file, respectively.

 # Auto generated interfaces
auto lo
iface lo inet loopback
auto venet0
iface venet0 inet static
        address 127.0.0.1
        netmask 255.255.255.255
        broadcast 0.0.0.0
        up route add -net 138.23.192.1 netmask 255.255.255.255 dev venet0
        up route add default gw 138.23.192.1

auto venet0:0
iface venet0:0 inet static
        address 192.168.16.53
        netmask 255.255.255.255
        broadcast 0.0.0.0
        up route add -net 192.168.16.0 netmask 255.255.255.0 dev venet0:0

auto venet0:1
iface venet0:1 inet static
        address 192.168.1.53
        netmask 255.255.255.255
        broadcast 0.0.0.0
        up route add -net 192.168.1.0 netmask 255.255.255.0 dev venet0:1
---
 etc/dists/scripts/debian-add_ip.sh |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/etc/dists/scripts/debian-add_ip.sh b/etc/dists/scripts/debian-add_ip.sh
index 331eef9..f40a090 100755
--- a/etc/dists/scripts/debian-add_ip.sh
+++ b/etc/dists/scripts/debian-add_ip.sh
@@ -79,13 +79,16 @@ function create_config()
 {
 	local ip=$1
 	local ifnum=$2
+	local network=${ip%.*}.0
+	local dev=${VENET_DEV}:${ifnum}
 
 	if [ "${ip#*:}" = "${ip}" ]; then
-	    echo -e "auto ${VENET_DEV}:${ifnum}
-iface ${VENET_DEV}:${ifnum} inet static
+	    echo -e "auto ${dev}
+iface ${dev} inet static
 	address ${ip}
 	netmask 255.255.255.255
 	broadcast 0.0.0.0
+	up route add -net ${network} netmask 255.255.255.0 dev ${dev}
 " >> ${CFGFILE}.bak
 
 	else
-- 
1.5.4.5