Is there no man page for dn_skipname() on purpose or is it an oversight? I found it on FreeBSD:
RESOLVER(3) FreeBSD Library Functions Manual RESOLVER(3) int dn_skipname(const u_char *comp_dn, const u_char *eom); DESCRIPTION The dn_skipname() function skips over a compressed domain name, which starts at a location pointed to by comp_dn. The compressed name is contained in a query or reply message; eom is a pointer to the end of the message. The size of compressed name is returned or -1 if there was an error.