network: Add BGP+EVPN+VXLAN script to main repository and Agent package

This script can be used to use BGP+EVPN for VXLAN instead of multicast.

In order to use the script operators need to manually create a symlink:

cd /usr/share
ln -s modifyvxlan.sh cloudstack-common/scripts/vm/network/vnet/modifyvxlan-evpn.sh

Configuring BGP and EVPN is outside of the scope of CloudStack and is
up to the operator to configure.

This commit just adds this script to the main repository and does not
change any existing functionality.

Author: wido

scripts/vm/network/vnet/modifyvxlan-evpn.sh

@@ -0,0 +1,162 @@
+#!/usr/bin/env bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+#
+# Use BGP+EVPN for VXLAN with CloudStack instead of Multicast
+#
+# The default 'modifyvxlan.sh' script from CloudStack uses Multicast instead of EVPN for VXLAN
+# In order to use this script and thus utilize BGP+EVPN, symlink this file:
+#
+# ln -s /usr/share/modifyvxlan.sh /usr/share/cloudstack-common/scripts/vm/network/vnet/modifyvxlan-evpn.sh
+#
+#
+# CloudStack will not handle the BGP configuration nor communication, the operator of the hypervisor will
+# need to configure the properly.
+#
+# Frrouting is recommend to be used on the hypervisor to establish BGP sessions with upstream routers and 
+# exchange BGP+EVPN information.
+#
+# More information about BGP and EVPN with FRR: https://vincent.bernat.ch/en/blog/2017-vxlan-bgp-evpn
+#
+
+DSTPORT=4789
+
+# We bind our VXLAN tunnel IP(v4) on Loopback device 'lo'
+DEV="lo"
+
+usage() {
+    echo "Usage: $0: -o <op>(add | delete) -v <vxlan id> -p <pif> -b <bridge name> (-6)"
+}
+
+localAddr() {
+    local FAMILY=$1
+
+    if [[ -z "$FAMILY" || $FAMILY == "inet" ]]; then
+       ip -4 -o addr show scope global dev ${DEV} | awk 'NR==1 {gsub("/[0-9]+", "") ; print $4}'
+    fi
+
+    if [[ "$FAMILY" == "inet6" ]]; then
+       ip -6 -o addr show scope global dev ${DEV} | awk 'NR==1 {gsub("/[0-9]+", "") ; print $4}'
+    fi
+}
+
+addVxlan() {
+    local VNI=$1
+    local PIF=$2
+    local VXLAN_BR=$3
+    local FAMILY=$4
+    local VXLAN_DEV=vxlan${VNI}
+    local ADDR=$(localAddr ${FAMILY})
+
+    echo "local addr for VNI ${VNI} is ${ADDR}"
+
+    if [[ ! -d /sys/class/net/${VXLAN_DEV} ]]; then
+        ip -f ${FAMILY} link add ${VXLAN_DEV} type vxlan id ${VNI} local ${ADDR} dstport ${DSTPORT} nolearning
+        ip link set ${VXLAN_DEV} up
+        sysctl -qw net.ipv6.conf.${VXLAN_DEV}.disable_ipv6=1
+    fi
+
+    if [[ ! -d /sys/class/net/$VXLAN_BR ]]; then
+        ip link add name ${VXLAN_BR} type bridge
+        ip link set ${VXLAN_BR} up
+        sysctl -qw net.ipv6.conf.${VXLAN_BR}.disable_ipv6=1
+    fi
+
+    bridge link show|grep ${VXLAN_BR}|awk '{print $2}'|grep "^${VXLAN_DEV}\$" > /dev/null
+    if [[ $? -gt 0 ]]; then
+        ip link set ${VXLAN_DEV} master ${VXLAN_BR}
+    fi
+}
+
+deleteVxlan() {
+    local VNI=$1
+    local PIF=$2
+    local VXLAN_BR=$3
+    local FAMILY=$4
+    local VXLAN_DEV=vxlan${VNI}
+
+    ip link set ${VXLAN_DEV} nomaster
+    ip link delete ${VXLAN_DEV}
+
+    ip link set ${VXLAN_BR} down
+    ip link delete ${VXLAN_BR} type bridge
+}
+
+OP=
+VNI=
+FAMILY=inet
+option=$@
+
+while getopts 'o:v:p:b:6' OPTION
+do
+  case $OPTION in
+  o)    oflag=1
+        OP="$OPTARG"
+        ;;
+  v)    vflag=1
+        VNI="$OPTARG"
+        ;;
+  p)    pflag=1
+        PIF="$OPTARG"
+        ;;
+  b)    bflag=1
+        BRNAME="$OPTARG"
+        ;;
+  6)
+        FAMILY=inet6
+        ;;
+  ?)    usage
+        exit 2
+        ;;
+  esac
+done
+
+if [[ "$oflag$vflag$pflag$bflag" != "1111" ]]; then
+    usage
+    exit 2
+fi
+
+lsmod|grep ^vxlan >& /dev/null
+if [[ $? -gt 0 ]]; then
+    modprobe=`modprobe vxlan 2>&1`
+    if [[ $? -gt 0 ]]; then
+        echo "Failed to load vxlan kernel module: $modprobe"
+        exit 1
+    fi
+fi
+
+
+#
+# Add a lockfile to prevent this script from running twice on the same host
+# this can cause a race condition
+#
+
+LOCKFILE=/var/run/cloud/vxlan.lock
+
+(
+    flock -x -w 10 200 || exit 1
+    if [[ "$OP" == "add" ]]; then
+        addVxlan ${VNI} ${PIF} ${BRNAME} ${FAMILY}
+
+        if [[ $? -gt 0 ]]; then
+            exit 1
+        fi
+    elif [[ "$OP" == "delete" ]]; then
+        deleteVxlan ${VNI} ${PIF} ${BRNAME} ${FAMILY}
+    fi
+) 200>${LOCKFILE}