ddns-scripts: refactor verify_dns()

quote variables
coalesce error conditions
code reads more cleanly and less 'stabby'.

Signed-off-by: Paul Donald <[email protected]>

diff --git a/net/ddns-scripts/files/usr/lib/ddns/dynamic_dns_functions.sh b/net/ddns-scripts/files/usr/lib/ddns/dynamic_dns_functions.sh
index ebafb629bc25f2f72ee8071c026d1b2b90525102..6ca7217c2f04fb7b1047aa780bf94c7d584d54be 100644 (file)
--- a/net/ddns-scripts/files/usr/lib/ddns/dynamic_dns_functions.sh
+++ b/net/ddns-scripts/files/usr/lib/ddns/dynamic_dns_functions.sh
@@ -551,37 +551,50 @@ verify_host_port() {
        fi
 }
 
-# verify given DNS server if connectable
+# Verify whether a given DNS server is reachable
 # $1   DNS server to verify
 verify_dns() {
-       local __ERR=255 # last error buffer
-       local __CNT=0   # error counter
+       local err attempt
+       err=255   # Last error code
+       attempt=0 # Retry attempt counter
 
-       [ $# -ne 1 ] && write_log 12 "Error calling 'verify_dns()' - wrong number of parameters"
-       write_log 7 "Verify DNS server '$1'"
+       [ "$#" -ne 1 ] && { write_log 12 "Error: 'verify_dns()' requires exactly 1 argument."; return 1; }
 
-       while [ $__ERR -ne 0 ]; do
-               # DNS uses port 53
-               verify_host_port "$1" "53"
-               __ERR=$?
-               if [ -n "$LUCI_HELPER" ]; then  # no retry if called by LuCI helper script
-                       return $__ERR
-               elif [ $__ERR -ne 0 -a $VERBOSE -gt 1 ]; then   # VERBOSE > 1 then NO retry
-                       write_log 4 "Verify DNS server '$1' failed - Verbose Mode: $VERBOSE - NO retry on error"
-                       return $__ERR
-               elif [ $__ERR -ne 0 ]; then
-                       __CNT=$(( $__CNT + 1 )) # increment error counter
-                       # if error count > retry_max_count leave here
-                       [ $retry_max_count -gt 0 -a $__CNT -gt $retry_max_count ] && \
-                               write_log 14 "Verify DNS server '$1' failed after $retry_max_count retries"
+       local dns_server="$1"
+       write_log 7 "Verifying DNS server: '$dns_server'"
 
-                       write_log 4 "Verify DNS server '$1' failed - retry $__CNT/$retry_max_count in $RETRY_SECONDS seconds"
-                       sleep $RETRY_SECONDS &
-                       PID_SLEEP=$!
-                       wait $PID_SLEEP # enable trap-handler
-                       PID_SLEEP=0
+       while [ "$err" -ne 0 ]; do
+               # Check connectivity to the DNS server on port 53
+               verify_host_port "$dns_server" "53"
+               err=$?
+
+               # Exit immediately if called by LuCI helper script
+               [ -n "$LUCI_HELPER" ] && return "$err"
+
+               if [ "$err" -ne 0 ]; then
+                       # If in verbose mode and connection fails, do not retry
+                       if [ "$VERBOSE" -gt 1 ]; then
+                               write_log 4 "Verification failed for DNS server '$dns_server' - Verbose Mode: $VERBOSE - No retries."
+                               return "$err"
+                       fi
+
+                       # Increment attempt counter and handle retry
+                       attempt=$((attempt + 1))
+
+                       # If max retries are exceeded, exit with failure
+                       if [ "$retry_max_count" -gt 0 ] && [ "$attempt" -gt "$retry_max_count" ]; then
+                               write_log 14 "Verification failed for DNS server '$dns_server' after $retry_max_count retries."
+                               return "$err"
+                       fi
+
+                       # Log the retry attempt and wait before retrying
+                       write_log 4 "Verification failed for DNS server '$dns_server' - Retry $attempt/$retry_max_count in $RETRY_SECONDS seconds."
+                       sleep "$RETRY_SECONDS" &
+                       wait $!  # Enable trap handler during sleep
                fi
        done
+
+       # Return success if the loop exits without errors
        return 0
 }