DHCP leasetime

[Ravi Paluri (QUIC)]

Hi all,
    We see that the DHCP leasetime can be configured either in days or hours or minutes etc. as below:
dhcp. at dhcp[0].leasetime='12h'

Query:
If we don't specify the letter i.e., d, h, or m and just specify the number (as below), then how does dnsmasq interpret the leasetime?
dhcp. at dhcp[0].leasetime='12'

If possible, can you point me to the source code for this?

Thanks,
Ravi