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.