[OpenWrt-Devel] [PATCH] netifd: proto-dhcp: handle alias interfaces

[Yury Shvedov]

The alias interfaces for interfaces with proto dhcp are very useful for
specialised builds with proto dhcp on lan by default but with backup static
addresses.

The default way has one shortage. It left backup address configured on
interface with address configured by odchp. This can lead to network
overlapping (when dhcp server configured on the same subnet with alias
interface) and to the addresses duplication inside broadcast domain
(when more then one board with same firmware running in subnet).

This patch introduces new option to dhcp proto. Just add

        option alias '<alias interface(s) name(s)>'

to the interface configuration and it will automatically downs alias
interfaces you specified upon dhcp address receiving.

Signed-off-by: Yury Shvedov <yshvedov at wimarksystems.com>
---
 .../config/netifd/files/lib/netifd/dhcp.script        | 11 ++++++++++-
 .../config/netifd/files/lib/netifd/proto/dhcp.sh      | 11 +++++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/package/network/config/netifd/files/lib/netifd/dhcp.script b/package/network/config/netifd/files/lib/netifd/dhcp.script
index 00604f40e7..8055b472ff 100755
--- a/package/network/config/netifd/files/lib/netifd/dhcp.script
+++ b/package/network/config/netifd/files/lib/netifd/dhcp.script
@@ -14,6 +14,11 @@ set_classless_routes() {
 }
 
 setup_interface () {
+	local i
+	for i in $ALIAS; do
+		ubus call network.interface."$i" down '{}'
+	done
+
 	proto_init_update "*" 1
 	proto_add_ipv4_address "$ip" "${subnet:-255.255.255.0}"
 	# TODO: apply $broadcast
@@ -21,7 +26,6 @@ setup_interface () {
 	local ip_net
 	eval "$(ipcalc.sh "$ip/$mask")";ip_net="$NETWORK"
 
-	local i
 	for i in $router; do
 		local gw_net
 		eval "$(ipcalc.sh "$i/$mask")";gw_net="$NETWORK"
@@ -93,6 +97,11 @@ setup_interface () {
 deconfig_interface() {
 	proto_init_update "*" 0
 	proto_send_update "$INTERFACE"
+
+	local i
+	for i in $ALIAS; do
+		ubus call network.interface."$i" up '{}'
+	done
 }
 
 case "$1" in
diff --git a/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh b/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
index a2b0ccedbf..15edab13bc 100755
--- a/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
+++ b/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
@@ -25,6 +25,7 @@ proto_dhcp_init_config() {
 	proto_config_add_string mtu6rd
 	proto_config_add_string customroutes
 	proto_config_add_boolean classlessroute
+	proto_config_add_string 'alias'
 }
 
 proto_dhcp_add_sendopts() {
@@ -35,8 +36,8 @@ proto_dhcp_setup() {
 	local config="$1"
 	local iface="$2"
 
-	local ipaddr hostname clientid vendorid broadcast release reqopts defaultreqopts iface6rd sendopts delegate zone6rd zone mtu6rd customroutes classlessroute
-	json_get_vars ipaddr hostname clientid vendorid broadcast release reqopts defaultreqopts iface6rd delegate zone6rd zone mtu6rd customroutes classlessroute
+	local ipaddr hostname clientid vendorid broadcast release reqopts defaultreqopts iface6rd sendopts delegate zone6rd zone mtu6rd customroutes classlessroute alias
+	json_get_vars ipaddr hostname clientid vendorid broadcast release reqopts defaultreqopts iface6rd delegate zone6rd zone mtu6rd customroutes classlessroute alias
 
 	local opt dhcpopts
 	for opt in $reqopts; do
@@ -60,6 +61,12 @@ proto_dhcp_setup() {
 	# Request classless route option (see RFC 3442) by default
 	[ "$classlessroute" = "0" ] || append dhcpopts "-O 121"
 
+	proto_export "ALIAS=$alias"
+	local i
+	for i in $alias; do
+		ubus call network.interface."$i" up '{}'
+	done
+
 	proto_export "INTERFACE=$config"
 	proto_run_command "$config" udhcpc \
 		-p /var/run/udhcpc-$iface.pid \
-- 
2.18.0


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