bridget/start.sh

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#!/bin/sh
CNI_CONFIG="${CNI_CONFIG:-/etc/cni/net.d/10-bridget.conf}"
usage() {
cat <<EOF
Available variables:
- BRIDGE (example: cbr0)
- VLAN (example: 100)
- IFACE (example: eth0)
- MTU (default: 1500)
- CHECK_SLAVES (example: 1)
- POD_NETWORK (default: 10.244.0.0/16)
- DIVISION_PREFIX (default: 24)"
- DEBUG (example: 1)
Short workflow:
* If bridge exists it will be used, if not exist it will be created
* If VLAN and IFACE is set, the next chain will be created:
IFACE <-- VLAN <-- BRIDGE
* If bridge have no IP-address it will be retrived automatically
This IP-address will be used as default gateway for containers
for make possible kubernetes-services.
EOF
}
error() {
>&2 echo -en "[$(date '+%Y-%m-%d %H:%M:%S')] ERROR:\t"
>&2 echo "$1"
>&2 usage
exit 1
}
log() {
echo -en "[$(date '+%Y-%m-%d %H:%M:%S')] INFO:\t"
echo "$1"
}
debug() {
if [ "$DEBUG" == 1 ]; then
echo -en "[$(date '+%Y-%m-%d %H:%M:%S')] DEBUG:\t"
echo "$1"
fi
}
next_ip() {
local IP_HEX=$(printf '%.2X%.2X%.2X%.2X\n' `echo $1 | sed -e 's/\./ /g'`)
local NEXT_IP_HEX=$(printf %.8X `echo $(( 0x$IP_HEX + 1 ))`)
local NEXT_IP=$(printf '%d.%d.%d.%d\n' `echo $NEXT_IP_HEX | sed -r 's/(..)/0x\1 /g'`)
echo $NEXT_IP
}
prev_ip() {
local IP_HEX=$(printf '%.2X%.2X%.2X%.2X\n' `echo $1 | sed -e 's/\./ /g'`)
local PREV_IP_HEX=$(printf %.8X `echo $(( 0x$IP_HEX - 1 ))`)
local PREV_IP=$(printf '%d.%d.%d.%d\n' `echo $PREV_IP_HEX | sed -r 's/(..)/0x\1 /g'`)
echo $PREV_IP
}
random_gateway() {
local IFS=
local NETWORKS_NUM="$(echo "$NETWORKS_LIST" | wc -l)"
local RANDOM_NETWORK_NUM="$(shuf -i "1-$NETWORKS_NUM" -n 1)"
local RANDOM_NETWORK="$(echo "$NETWORKS_LIST" | head -n "$RANDOM_NETWORK_NUM" | tail -n 1)"
unset IFS
local RANDOM_GATEWAY="$(next_ip $RANDOM_NETWORK)"
echo "$RANDOM_GATEWAY"
}
unused_gateway() {
[ -f "$CNI_CONFIG" ] && local UNUSED_GATEWAY=$(sed -n 's/.*"gateway": "\(.*\)",/\1/p' "$CNI_CONFIG")
if [ -z $UNUSED_GATEWAY ] || ! right_gateway "$UNUSED_GATEWAY"; then
UNUSED_GATEWAY="$(random_gateway)"
fi
while arping -i "$BRIDGE" -S 0.0.0.0 -c 4 "$UNUSED_GATEWAY" 1>/dev/null; do
local UNUSED_GATEWAY="$(random_gateway)"
done
echo "$UNUSED_GATEWAY"
}
right_gateway() {
(IFS= echo "$NETWORKS_LIST") | grep -q "$(prev_ip $1)"
}
# ------------------------------------------------------------------------------------
# Configure bridge
# ------------------------------------------------------------------------------------
log "Starting bridge configuration"
[ -z "$BRIDGE" ] && error "BRIDGE variable is not defined"
# Check if bridge interface exist
if ! ip link show "$BRIDGE" &> /dev/null; then
log "Adding new bridge $BRIDGE"
ip link add dev "$BRIDGE" type bridge
export CHECK_SLAVES=1
else
log "Bridge $BRIDGE already exist, use it"
fi
log "Setting bridge $BRIDGE up"
ip link set "$BRIDGE" up
# ------------------------------------------------------------------------------------
# Configure vlan
# ------------------------------------------------------------------------------------
if ([ ! -z "$VLAN" ] || [ ! -z "$IFACE" ]) && [ "$CHECK_SLAVES" == 1 ]; then
log "Starting VLAN configuration"
[ -z "$IFACE" ] && error "IFACE variable is not defined"
if [ ! -z "$VLAN" ]; then
# check if vlan interface exist
if ip link show "$IFACE.$VLAN" &> /dev/null; then
log "VLAN interface $IFACE.$VLAN already exist"
else
log "Adding new VLAN interface $IFACE.$VLAN"
ip link add link "$IFACE" name "$IFACE.$VLAN" type vlan id "$VLAN"
fi
log "Setting vlan $IFACE.$VLAN up"
ip link set dev "$IFACE.$VLAN" up
fi
fi
# ------------------------------------------------------------------------------------
# Configure slaves
# ------------------------------------------------------------------------------------
if ([ ! -z "$VLAN" ] || [ ! -z "$IFACE" ]) && [ "$CHECK_SLAVES" == 1 ]; then
log "Starting configuring slave interfaces"
if [ ! -z "$VLAN" ]; then
SLAVEIF="$IFACE.$VLAN"
else
SLAVEIF="$IFACE"
fi
if ! ip link show "$SLAVEIF" &> /dev/null; then
error "$SLAVEIF does not exist"
fi
# check if slave interface contains right master
MASTERIF="$(ip -o link show "$SLAVEIF" | grep -o -m1 'master [^ ]\+' | cut -d' ' -f2 )"
case "$MASTERIF" in
"$BRIDGE" ) log "$SLAVEIF already member of $BRIDGE" ;;
"" ) log "Adding $SLAVEIF as member to $BRIDGE"
ip link set "$SLAVEIF" master "$BRIDGE" ;;
* ) error "interface $SLAVEIF have another master" ;;
esac
fi
# ------------------------------------------------------------------------------------
# Retrive network parameters
# ------------------------------------------------------------------------------------
log "Starting retriving parameters"
POD_NETWORK="${POD_NETWORK:-10.244.0.0/16}"
DIVISION_PREFIX="${DIVISION_PREFIX:-24}"
log "POD_NETWORK=$POD_NETWORK"
log "DIVISION_PREFIX=$DIVISION_PREFIX"
set -e
export "POD_$(ipcalc -p "$POD_NETWORK")" # POD_PREFIX
export "POD_$(ipcalc -b "$POD_NETWORK")" # POD_BROADCAST
export "POD_$(ipcalc -n "$POD_NETWORK")" # POD_NETWORK
export "FIRST_$(ipcalc -n "$POD_NETWORK/$DIVISION_PREFIX" )" # FIRST_NETWORK
export "LAST_$(ipcalc -n "$POD_BROADCAST/$DIVISION_PREFIX" )" # LAST_NETWORK
set +e
debug "POD_PREFIX=$POD_PREFIX"
debug "POD_BROADCAST=$POD_BROADCAST"
debug "POD_NETWORK=$POD_NETWORK"
debug "FIRST_NETWORK=$FIRST_NETWORK"
debug "LAST_NETWORK=$LAST_NETWORK"
NETWORKS_LIST="$(
CUR_NETWORK="$LAST_NETWORK"
until [ "$CUR_NETWORK" == "$FIRST_NETWORK" ]; do
echo "$CUR_NETWORK"
export CUR_"$(ipcalc -n "$(prev_ip "$CUR_NETWORK")/$DIVISION_PREFIX")"
done
)"
debug "NETWORKS_LIST=\"$(echo "$NETWORKS_LIST" | tr '\n' ' ' )\""
# ------------------------------------------------------------------------------------
# Configure IP-address
# ------------------------------------------------------------------------------------
log "Starting configuring IP-address"
# Check ip address
IPADDR="$(ip -f inet -o addr show "$BRIDGE" | grep -o -m1 'inet [^ /]*' | cut -d' ' -f2)"
# If ip not exist
if [ -z "$IPADDR" ]; then
log "Retrieving IP-address"
IPADDR="$(unused_gateway)"
log "Successful retrived $IPADDR"
log "Configuring $IPADDR/$POD_PREFIX on $BRIDGE"
ip addr change "$IPADDR/$POD_PREFIX" dev "$BRIDGE"
else
if ! right_gateway "$IPADDR"; then
error "$BRIDGE already have IP address not from the list"
fi
log "IP-address $IPADDR already set, use it"
fi
# ------------------------------------------------------------------------------------
# Configure cni
# ------------------------------------------------------------------------------------
log "Starting generating CNI configuration"
set -e
GATEWAY="$IPADDR"
SUBNET="${POD_NETWORK}/${POD_PREFIX}"
FIRST_IP="$(next_ip "${GATEWAY}")"
LAST_IP="$(prev_ip "$(ipcalc -b "${GATEWAY}/${DIVISION_PREFIX}" | cut -d= -f2)")"
set +e
debug "GATEWAY=$GATEWAY"
debug "SUBNET=$SUBNET"
debug "FIRST_IP=$FIRST_IP"
debug "LAST_IP=$LAST_IP"
log "Writing $CNI_CONFIG"
cat > $CNI_CONFIG <<EOT
{
"name": "bridget",
"type": "bridge",
"bridge": "${BRIDGE}",
"ipMasq": true,
"mtu": ${MTU:-1500},
"ipam": {
"type": "host-local",
"subnet": "${SUBNET}",
"rangeStart": "${FIRST_IP}",
"rangeEnd": "${LAST_IP}",
"gateway": "${GATEWAY}",
"routes": [
{ "dst": "0.0.0.0/0" }
]
}
}
EOT
debug "$(cat "$CNI_CONFIG")"
# ------------------------------------------------------------------------------------
# Sleep gently
# ------------------------------------------------------------------------------------
tail -f /dev/null