in6_pcbselsrc
error = in6_pcbselsrc(&in6a, sin6, inp, inp->inp_outputopts6);
int in6_pcbselsrc(const struct in6_addr **, const struct sockaddr_in6 *,
error = in6_pcbselsrc(&in6a, satosin6(dstaddr), inp, optp);
error = in6_pcbselsrc(&in6a, addr, inp, inp->inp_outputopts6);
error = in6_pcbselsrc(&laddr, sin6, inp, optp);