ddns-scripts: ddns-update-netcup-com.sh is never updating ...

Package Name

ddns-scripts-netcup-com

Maintainer

(@feckert)

OpenWrt Version

25.12.5

OpenWrt Target/Subtarget

all

Steps to Reproduce

1. create a entry @ netcup dns (subdomain, AAAA, ipv6 short version i.e.: 2000:6000:4000:c000::de
2. install netcup script
3. configure ddns
4. run update

Actual Behaviour

The ddns-update-netcup-com.sh script is not updating any DNS records.
This is due to the following code sequence, which is executed in a loop for each DNS record delivered by the Netcup-API:

if [ "$__rec_type" = "$__RRTYPE" ] \
&& [ "$__rec_name" = "$__REC_HOSTNAME" ] \
&& [ "$__rec_destination" = "$REGISTERED_IP" ];` then
   __MATCH_ID="$__rec_id"
   write_log 7 "netcup DDNS: matched record id=$__MATCH_ID"
   break
fi

If, for example, the IPv6 address 2000:6000:4000:c000::de is stored at Netcup, the variable $__rec_destination contains the value 2000:6000:4000:c000::de However, the variable $REGISTERED_IP contains 2000:6000:4000:c000:0000:0000:0000:00de

In my opinion, comparing the IPs in the if statement is generaly pointless, as this prevents an update in all cases.
Maybe its helpful to avoid useless updates. But $REGISTERED_IP is not useful here ...

I have replaced the existing statement with a nested if statement (for performance reasons).

if [ "$__rec_type" = "$__RRTYPE" ]; then
   # compare hostname only if type always matches
   if [ "$__rec_name" = "$__REC_HOSTNAME" ]; then
      __MATCH_ID="$__rec_id"
      write_log 7 "netcup DDNS: matched record id=$__MATCH_ID"
      break
   fi
fi

Confirmation Checklist

• The package is maintained in this repository.
• I understand that issues related to the base OpenWrt repository or LuCI repository will be closed.
• I am reporting an issue for OpenWrt, not an unsupported fork.

Start with ddns-update-netcup-com.sh and reproduce the Netcup DNS update using an IPv6 address in compressed form. Check the record-matching logic and any existing package tests or update logs; done means the script finds the existing record and updates it correctly without preventing other record updates.