find netmask for offered lease in dhclient code

[s m]

hello all,
i want to change dhclient code and customize it. in order to do that, i
need to know the netmask for offered ip. i see code and found that struct
client_lease  *offered_leases, keeps information about offered lease such
as ip address but this structure hasn't any field about netmask. i don't
know how i can find the netmak for this offered ip address.

any one has traced dhclient code before? how can i see the netmask for
offered ip?

thanks in advance,
SAM