[openwrt/openwrt] comgt: ncm: allow specification of interface name

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/c138cb80e9abbb431fede49870f7640abcdd2662

commit c138cb80e9abbb431fede49870f7640abcdd2662
Author: Lech Perczak <lech.perczak at gmail.com>
AuthorDate: Thu Mar 31 21:16:01 2022 +0200

    comgt: ncm: allow specification of interface name
    
    Add ifname property to UCI, which can be used to override the
    autodetected interface name in case the detection fails due to having
    none or more than one interface exposed by the modem, which is not
    explicitly linked to TTY port. This is needed on certain variants of ZTE
    MF286R built-in modem, which exposes both RNDIS and CDC-ECM interfaces
    on the modem, on which the automatic detection may select the wrong
    network interface.
    
    Signed-off-by: Lech Perczak <lech.perczak at gmail.com>
    (cherry picked from commit a67629bbe25ef3d0e159db1e0c6ca81affd06898)
---
 package/network/utils/comgt/files/ncm.sh | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/package/network/utils/comgt/files/ncm.sh b/package/network/utils/comgt/files/ncm.sh
index 6545091c82..38a4ba7a0b 100644
--- a/package/network/utils/comgt/files/ncm.sh
+++ b/package/network/utils/comgt/files/ncm.sh
@@ -10,6 +10,7 @@ proto_ncm_init_config() {
 	no_device=1
 	available=1
 	proto_config_add_string "device:device"
+	proto_config_add_string ifname
 	proto_config_add_string apn
 	proto_config_add_string auth
 	proto_config_add_string username
@@ -25,10 +26,10 @@ proto_ncm_init_config() {
 proto_ncm_setup() {
 	local interface="$1"
 
-	local manufacturer initialize setmode connect finalize ifname devname devpath
+	local manufacturer initialize setmode connect finalize devname devpath
 
-	local device apn auth username password pincode delay mode pdptype profile $PROTO_DEFAULT_OPTIONS
-	json_get_vars device apn auth username password pincode delay mode pdptype profile $PROTO_DEFAULT_OPTIONS
+	local device ifname  apn auth username password pincode delay mode pdptype profile $PROTO_DEFAULT_OPTIONS
+	json_get_vars device ifname apn auth username password pincode delay mode pdptype profile $PROTO_DEFAULT_OPTIONS
 
 	[ "$metric" = "" ] && metric="0"
 
@@ -53,17 +54,20 @@ proto_ncm_setup() {
 		return 1
 	}
 
-	devname="$(basename "$device")"
-	case "$devname" in
-	'tty'*)
-		devpath="$(readlink -f /sys/class/tty/$devname/device)"
-		ifname="$( ls "$devpath"/../../*/net )"
-		;;
-	*)
-		devpath="$(readlink -f /sys/class/usbmisc/$devname/device/)"
-		ifname="$( ls "$devpath"/net )"
-		;;
-	esac
+	[ -z "$ifname" ] && {
+		devname="$(basename "$device")"
+		case "$devname" in
+		'tty'*)
+			devpath="$(readlink -f /sys/class/tty/$devname/device)"
+			ifname="$( ls "$devpath"/../../*/net )"
+			;;
+		*)
+			devpath="$(readlink -f /sys/class/usbmisc/$devname/device/)"
+			ifname="$( ls "$devpath"/net )"
+			;;
+		esac
+	}
+
 	[ -n "$ifname" ] || {
 		echo "The interface could not be found."
 		proto_notify_error "$interface" NO_IFACE