wit-network-config/files/qemu-ifup-public

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#!/bin/bash
set -Eeuo pipefail
IFACE=$1
if [ ${#IFACE} -gt 14 ]; then
echo "interface name too long, mac 14 char: $IFACE"
exit 10
fi
source /etc/libvirt/hooks/$IFACE
### PUBLICMAC should always be set, keeping this for compatibility with libvirt.
### the MAC the VM has been assigned by qemu needs to be known here, but AFAIK libvirt doesn't support exporting env vars to ifup script, so this needs to be static on the public interface in qemu
### if this is not set correctly the routing in the VM won't work
: ${PUBLICMAC:=52:54:00:00:00:11}
###
maxprefixv6=56
maxprefixv4=25
if [ -z $IP ]; then
echo "got nothing back from the API"
exit 10
fi
eui64() {
local macaddr="$1"
printf "%02x%s" $(( 16#${macaddr:0:2} ^ 2#00000010 )) "${macaddr:2}" \
| sed -E -e 's/([0-9a-zA-Z]{2})*/0x\0|/g' \
| tr -d ':\n' \
| xargs -d '|' \
printf "fe80::%02x%02x:%02xff:fe%02x:%02x%02x"
}
gwmac() {
### libvirt replaces the first octet in the mac with fe, so may as well stick to that for consistency,
### the only thing that matters is that we know and it's predictable from within the VM
local macaddr="$1"
printf "%02x%s" "0xfe" "${macaddr:2}"
}
ip link set ${IFACE} address $(gwmac $PUBLICMAC) up
arp -i ${IFACE} -s 169.254.0.1 ${PUBLICMAC}
sysctl -w net.ipv4.conf.${IFACE/./\/}.arp_ignore=8
IFS=',' read -ra IPS <<< "$IP"
for IP in "${IPS[@]}"; do
if [[ $IP =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/([0-9]{2})$ ]]; then ### we got a IPv4 prefix < maxprefixv4
if [ ${BASH_REMATCH[1]} -lt $maxprefixv4 ]; then
echo "we don't support such a big customer net?"
continue
fi
if [ ${BASH_REMATCH[1]} -gt 32 ]; then
echo "prefix is invalid"
continue
fi
echo "we got IPv4 with prefix ${BASH_REMATCH[0]}"
ip route add ${IP} via 169.254.0.1 dev ${IFACE} onlink metric 1
ip route add ${IP} dev ${IFACE} metric 255
elif [[ $IP =~ ^2604:bbc0:[0-9,a-f,:]{1,444}/([0-9]{2,3})$ ]]; then ### we got a PIv6 prefix < masprefixv6
if [ ${BASH_REMATCH[1]} -lt $maxprefixv6 ]; then
echo "we don't support such a big customer net?"
continue
fi
if [ ${BASH_REMATCH[1]} -gt 128 ]; then
echo "prefix is invalid"
continue
fi
echo "we got IPv6 with prefix ${BASH_REMATCH[0]}"
ip route add ${IP} dev ${IFACE} via $(eui64 $PUBLICMAC)
elif [[ $IP =~ ^\ *$ ]]; then
echo "we just got an empty string. so not gonna do anything. probably due to splitting the comma"
else
echo "Unable to detect with what prefix I'm working with"
exit 10
fi
done