`smartdns`: `dhcp_option` incorrectly includes CIDR suffix from network.lan.ipaddr

Start with /etc/init.d/smartdns and inspect set_main_dns(), especially the network.lan.ipaddr lookup and dhcp_option update. Reproduce the behavior with the listed UCI commands and restart sequence. Done means DHCP option 6 contains only plain IP addresses and repeated restarts do not add invalid or duplicate entries.

Package Name

smartdns

Maintainer

Nick Peng pymumu@gmail.com

OpenWrt Version

25.12.2

OpenWrt Target/Subtarget

mediatek/filogic

Steps to Reproduce

1. Use OpenWrt 23.x / 24.x / 25.x (DSA-based system)

2. Ensure LAN IP is in CIDR format:

uci get network.lan.ipaddr
# example output:
192.168.1.1/24

3. Ensure no existing DHCP option 6 (optional, for clean test):

uci del dhcp.lan.dhcp_option
uci commit dhcp

4. Restart smartdns:

/etc/init.d/smartdns restart

5. Check DHCP options:

uci show dhcp | grep dhcp_option

Actual Behaviour

/etc/init.d/smartdns executes set_main_dns() (lines ~87–107):

set_main_dns() {
    local hostip
    hostip="$(uci -q get network.lan.ipaddr)"      # retrieves LAN IP
    dnsmasq_port="$(uci -q get dhcp.@dnsmasq[0].port)"
    [ -z "$dnsmasq_port" ] && dnsmasq_port="53"

    [ -z "$hostip" ] && return
    [ "$dnsmasq_port" = "53" ] && {
        uci -q set dhcp.@dnsmasq[0].port=0
        uci -q add_list dhcp.lan.dhcp_option="6,$hostip"   # <-- adds DHCP option
    }
    uci commit dhcp
}

root@OpenWrt:~# uci get network.lan.ipaddr
192.168.1.1/24

After /etc/init.d/smartdns restart

uci show dhcp | grep dhcp_option
dhcp.lan.dhcp_option='6,192.168.1.1' '6,192.168.1.1/24' # <-- invalid, breaks DHCP

Consequences:

DHCP option 6 expects plain IP addresses; /24 suffix leads to invalid DNS assignment (24.192.168.1 on clients).
Duplicate entries accumulate on multiple restarts.
Breaks DNS resolution on all DHCP clients.

Expected Behavior:

dhcp.lan.dhcp_option should only contain plain IP addresses, without CIDR.
Restarting smartdns should not introduce invalid or duplicate DHCP options.

Notes / Additional Info:

The problematic code is specific to set_main_dns() in /etc/init.d/smartdns.
Root cause: the script blindly appends network.lan.ipaddr to dhcp_option without stripping CIDR.

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.