Merge pull request #2530 from SimonFair/fix(INET)-fix-ip-v6-DNS-issue

fix(INET): fix ip v6 dns issue with ending ::

Author: limetech

etc/rc.d/rc.inet1.conf

@@ -34,8 +34,27 @@ unzero(){
 # function to remove leading zeros in IPv6 address
 unzero6(){
   local A M Q
+  if [[ $1 == "::" ]]; then
+    printf "::"
+    return 0
+  fi
+  # Replace first :: with sentinel
   A=${1/::/:-:}
-  echo -n $(for Q in ${A//:/ }; do [[ $Q != - ]] && printf "$M%x" "0x$Q" || printf ":"; M=:; done)
+  M=
+  for Q in ${A//:/ }; do
+    if [[ $Q != - ]]; then
+      # Validate hex (1-4 digits)
+      [[ $Q =~ ^[0-9A-Fa-f]{1,4}$ ]] || return 1
+      printf "%s%x" "$M" "0x$Q"
+    else
+      # Restore a single colon for sentinel
+      printf ":"
+    fi
+    M=:
+  done
+
+  # Handle trailing :: (but avoid adding for the special case "::")
+  [[ $1 == *:: && $1 != "::" ]] && printf ":"
 }
 
 # Bergware - use associative format for multi-dimensional arrays