Construct host name for reverse lookup
#include <dns.h>
void dns_name6_domain(char q[DNS_NAME6_DOMAIN],
const char* ip[16]);
dns_name6_domain is a low-level component of dns_name6. It converts an IP address such as 4321:0:1:2:3:4:567:89ab into a domain name such as b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6.ARPA and places the packet-encoded domain name into q.
q is zero terminated.
q must have space for DNS_NAME6_DOMAIN bytes.