From 31813e92199386f19dd7e993a9e951d293503a01 Mon Sep 17 00:00:00 2001
From: Brian Haley <brian.haley@hpe.com>
Date: Mon, 22 Aug 2016 15:39:22 -0400
Subject: [PATCH] Let neutron use default gateway IP for subnets

By default, FIXED_RANGE and NETWORK_GATEWAY (and the
IPv6 equivalents) are in the same subnet.  But if
FIXED_RANGE is over-ridden in local.conf we could
create a subnet with an invalid gateway address.

Since neutron will pick the lowest host IP as the
gateway by default, do not specify them unless the
user has specifically set them.

Do this for both the private and public subnets, as
well as the public IPv4 subnet.

Change-Id: Ifc71400a3af1f131bb8a9722188e13de5bd3c806
---
 lib/neutron_plugins/services/l3 | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index a4e72483b4..c6f14d35f6 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -63,14 +63,14 @@ IPV6_ADDRESS_MODE=${IPV6_ADDRESS_MODE:-slaac}
 IPV6_PUBLIC_SUBNET_NAME=${IPV6_PUBLIC_SUBNET_NAME:-ipv6-public-subnet}
 IPV6_PRIVATE_SUBNET_NAME=${IPV6_PRIVATE_SUBNET_NAME:-ipv6-private-subnet}
 FIXED_RANGE_V6=${FIXED_RANGE_V6:-fd$IPV6_GLOBAL_ID::/64}
-IPV6_PRIVATE_NETWORK_GATEWAY=${IPV6_PRIVATE_NETWORK_GATEWAY:-fd$IPV6_GLOBAL_ID::1}
+IPV6_PRIVATE_NETWORK_GATEWAY=${IPV6_PRIVATE_NETWORK_GATEWAY:-}
 IPV6_PUBLIC_RANGE=${IPV6_PUBLIC_RANGE:-2001:db8::/64}
 IPV6_PUBLIC_NETWORK_GATEWAY=${IPV6_PUBLIC_NETWORK_GATEWAY:-2001:db8::2}
 IPV6_ROUTER_GW_IP=${IPV6_ROUTER_GW_IP:-2001:db8::1}
 
 # Gateway and subnet defaults, in case they are not customized in localrc
-NETWORK_GATEWAY=${NETWORK_GATEWAY:-10.0.0.1}
-PUBLIC_NETWORK_GATEWAY=${PUBLIC_NETWORK_GATEWAY:-172.24.4.1}
+NETWORK_GATEWAY=${NETWORK_GATEWAY:-}
+PUBLIC_NETWORK_GATEWAY=${PUBLIC_NETWORK_GATEWAY:-}
 PRIVATE_SUBNET_NAME=${PRIVATE_SUBNET_NAME:-"private-subnet"}
 PUBLIC_SUBNET_NAME=${PUBLIC_SUBNET_NAME:-"public-subnet"}
 
@@ -234,7 +234,9 @@ function _neutron_create_private_subnet_v4 {
     local project_id=$1
     local subnet_params="--tenant-id $project_id "
     subnet_params+="--ip_version 4 "
-    subnet_params+="--gateway $NETWORK_GATEWAY "
+    if [[ -n "$NETWORK_GATEWAY" ]]; then
+        subnet_params+="--gateway $NETWORK_GATEWAY "
+    fi
     subnet_params+="--name $PRIVATE_SUBNET_NAME "
     subnet_params+="$NET_ID $FIXED_RANGE"
     local subnet_id
@@ -251,7 +253,9 @@ function _neutron_create_private_subnet_v6 {
     local ipv6_modes="--ipv6-ra-mode $IPV6_RA_MODE --ipv6-address-mode $IPV6_ADDRESS_MODE"
     local subnet_params="--tenant-id $project_id "
     subnet_params+="--ip_version 6 "
-    subnet_params+="--gateway $IPV6_PRIVATE_NETWORK_GATEWAY "
+    if [[ -n "$IPV6_PRIVATE_NETWORK_GATEWAY" ]]; then
+        subnet_params+="--gateway $IPV6_PRIVATE_NETWORK_GATEWAY "
+    fi
     subnet_params+="--name $IPV6_PRIVATE_SUBNET_NAME "
     subnet_params+="$NET_ID $FIXED_RANGE_V6 $ipv6_modes"
     local ipv6_subnet_id
@@ -262,9 +266,11 @@ function _neutron_create_private_subnet_v6 {
 
 # Create public IPv4 subnet
 function _neutron_create_public_subnet_v4 {
-    local subnet_params+="--ip_version 4 "
+    local subnet_params="--ip_version 4 "
     subnet_params+="${Q_FLOATING_ALLOCATION_POOL:+--allocation-pool $Q_FLOATING_ALLOCATION_POOL} "
-    subnet_params+="--gateway $PUBLIC_NETWORK_GATEWAY "
+    if [[ -n "$PUBLIC_NETWORK_GATEWAY" ]]; then
+        subnet_params+="--gateway $PUBLIC_NETWORK_GATEWAY "
+    fi
     subnet_params+="--name $PUBLIC_SUBNET_NAME "
     subnet_params+="$EXT_NET_ID $FLOATING_RANGE "
     subnet_params+="-- --enable_dhcp=False"