comgt: ncm: select first available network interface for device

Some modems expose multiple network interfaces on the same USB device,
causing the connection setup script to fail, because glob matching in
the detection phase causes 'ls' to output more than one interface name
plus their base directories in sysfs. Avoid that by listing the
directories explicitly and then selecting first available interface.
This is the case for some variants of ZTE MF286R built-in modem, which
exposes both RNDIS and CDC-ECM network interfaces, causing the
connection setup to fail.

Signed-off-by: Lech Perczak <lech.perczak@gmail.com>
(cherry picked from commit b2940bb8b2878ce193f2edaee3e7d4c44f4a2065)

diff --git a/package/network/utils/comgt/files/ncm.sh b/package/network/utils/comgt/files/ncm.sh
index 38a4ba7a0bfdd6b96e542e315025f6dbf1ae792f..c3a06165efc7da1583e624cc0d0d71add36cb34b 100644 (file)
--- a/package/network/utils/comgt/files/ncm.sh
+++ b/package/network/utils/comgt/files/ncm.sh
@@ -26,7 +26,7 @@ proto_ncm_init_config() {
 proto_ncm_setup() {
        local interface="$1"
 
-       local manufacturer initialize setmode connect finalize devname devpath
+       local manufacturer initialize setmode connect finalize devname devpath ifpath
 
        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 $PROTO_DEFAULT_OPTIONS
@@ -59,13 +59,14 @@ proto_ncm_setup() {
                case "$devname" in
                'tty'*)
                        devpath="$(readlink -f /sys/class/tty/$devname/device)"
-                       ifname="$( ls "$devpath"/../../*/net )"
+                       ifpath="$devpath/../../*/net"
                        ;;
                *)
                        devpath="$(readlink -f /sys/class/usbmisc/$devname/device/)"
-                       ifname="$( ls "$devpath"/net )"
+                       ifpath="$devpath/net"
                        ;;
                esac
+               ifname="$(ls $(ls -1 -d $ifpath | head -n 1))"
        }
 
        [ -n "$ifname" ] || {