ipsec_build_id
conn->local_id = ipsec_build_id(local_id, &conn->local_sz);
conn->remote_id = ipsec_build_id(remote_id, &conn->remote_sz);
id = ipsec_build_id(local_id, &sz);
id = ipsec_build_id(remote_id, &sz);
id = ipsec_build_id(remote_id, &sz);
if ((nat_id = ipsec_build_id(nat, &nat_sz))) {
extern u_int8_t *ipsec_build_id(char *, size_t *);