[openwrt/openwrt] uqmi: use correct value for connection checking

[LEDE Commits]

blogic pushed a commit to openwrt/openwrt.git, branch lede-17.01:
https://git.lede-project.org/e9eb219e5a07f3e2284c1483da03d5accb130eac

commit e9eb219e5a07f3e2284c1483da03d5accb130eac
Author: Koen Vandeputte <koen.vandeputte at ncentric.com>
AuthorDate: Thu Feb 15 15:16:02 2018 +0100

    uqmi: use correct value for connection checking
    
    Originally, the implementation only checked if uqmi command
    execution succeeded properly without actually checking it's returned data.
    
    This lead to a pass, even when the returned data was indicating an error.
    
    Rework the verification to actually check the returned data,
    which can only be correct if the uqmi command itself also executed correctly.
    
    On command execution success, value "pdh_" is a pure numeric value.
    
    Signed-off-by: Koen Vandeputte <koen.vandeputte at ncentric.com>
---
 package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh b/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
index eba0922..bdab5ee 100755
--- a/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
+++ b/package/network/utils/uqmi/files/lib/netifd/proto/qmi.sh
@@ -156,12 +156,14 @@ proto_qmi_setup() {
 			${username:+--username $username} \
 			${password:+--password $password} \
 			${autoconnect:+--autoconnect})
-		[ $? -ne 0 ] && {
+
+        # pdh_4 is a numeric value on success
+		if ! [ "$pdh_4" -eq "$pdh_4" ] 2> /dev/null; then
 			echo "Unable to connect IPv4"
 			uqmi -s -d "$device" --set-client-id wds,"$cid_4" --release-client-id wds
 			proto_notify_error "$interface" CALL_FAILED
 			return 1
-		}
+		fi
 	}
 
 	[ "$pdptype" = "ipv6" -o "$pdptype" = "ipv4v6" ] && {
@@ -182,12 +184,14 @@ proto_qmi_setup() {
 			${username:+--username $username} \
 			${password:+--password $password} \
 			${autoconnect:+--autoconnect})
-		[ $? -ne 0 ] && {
+
+        # pdh_6 is a numeric value on success
+		if ! [ "$pdh_6" -eq "$pdh_6" ] 2> /dev/null; then
 			echo "Unable to connect IPv6"
 			uqmi -s -d "$device" --set-client-id wds,"$cid_6" --release-client-id wds
 			proto_notify_error "$interface" CALL_FAILED
 			return 1
-		}
+		fi
 	}
 
 	echo "Setting up $ifname"