dhcp_duid2str
dhcp_duid2str(iface->serverid_len, iface->serverid));
if_name, dhcp_duid2str(iface->serverid_len,
dhcp_duid2str(iface->serverid_len, iface->serverid));
dhcp_duid2str(iface->serverid_len, iface->serverid));
const char *dhcp_duid2str(int, uint8_t *);
dhcp_duid2str(opt_hdr.len, p));