dns_ip4_packet man page
dns_ip4_packet — extract IPv4 address from DNS answer packet
int dns_ip4_packet(stralloc* out,const char* buf,
unsigned int len);
dns_ip4_packet is a low-level component of dns_ip4, designed to support asynchronous DNS lookups. It reads a DNS packet of length len from buf, extracts IP addresses from the answer section of the packet, puts the addresses into out, and returns 0 or -1 the same way as dns_ip4.
dns_ip4(3), dns_ip4_qualify(3), dns_ip6_packet(3), dns_name_packet(3).