get_option_addr
if (get_option_addr(&net, dhcp, DHO_SUBNETMASK) == -1)
if (get_option_addr(&lease->net, dhcp, DHO_SUBNETMASK) == -1)
if (get_option_addr(&lease->brd, dhcp, DHO_BROADCAST) == -1)
if (get_option_addr(&lease->server, dhcp, DHO_SERVERID) != 0)
int get_option_addr(struct in_addr *, const struct dhcp_message *, uint8_t);