I've been using the nbt images, and I'm finding that the ipcalc command has changed and is not reporting the prefix properly (or at least what I understand the prefix should be). I used the old one to produce a CIDR number for my firewall.user scripts and other IPSEC related tools. I've created a work around, but I think the PREFIX is not right, as it is always showing up as 8. Here are some notes on the situation.

the one I'm used to reports this...

~# ipcalc
BusyBox v1.00 (2006.02.18-21:41+0000) multi-call binary

Usage: ipcalc [OPTION]... <ADDRESS>[[/]<NETMASK>] [NETMASK]

Calculate IP network settings from a IP address

Options:
        -b      --broadcast     Display calculated broadcast address.
        -n      --network       Display calculated network address.
        -m      --netmask       Display default netmask for IP.
        -p      --prefix        Display the prefix for IP/NETMASK.      -h     --hostname       Display first resolved host name.
        -s      --silent        Don't ever display error messages.

And the new one shows this...

~# ipcalc
IP=0
NETMASK=0
BROADCAST=255.255.255.255
NETWORK=0
PREFIX=0

I've found that ipcalc also shows up in the /etc/init.d/S50dnsmasq script so I'm sure there was a reason for changing the functionality of this, but I don't understand it, and I can't seem to make it report a correct prefix.
Thanks
-hanz

The syntax is

ipcalc <ip> <netmask>

Or, optionally

ipcalc <ip> <netmask> <start> <number>

which is used for calculating ranges for things like dnsmasq

I see, however the prefix still is different. Here is the new version...

~# ipcalc 10.0.0.1 255.255.255.240
IP=10.0.0.1
NETMASK=255.255.255.240
BROADCAST=10.0.0.15
NETWORK=10.0.0.0
PREFIX=8

and the old version with the prefix switch

~# ipcalc -p 10.0.0.1 255.255.255.240
PREFIX=28

And the shell scripts that I was writing needed the CIDR from the PREFIX to fill in some iptables commands. I got around it by applying a cludge because my math/scripting skills aren't that good.

LM=$(nvram get lan_netmask)
LD=$(echo $LM|awk -F. '{print $4}')
case $LD in 255) LD=32;; 254) LD=31;; 252) LD=30;; 248) LD=29;; 240) LD=28;; 224) LD=27;; 192) LD=26;; 128) LD=25;; 0) LD=24;; *) LD=;; esac

Thanks again
-hanz

https://dev.openwrt.org/changeset/3475