// may be set using CMSG_SPACE (which includes padding) or
// using CMSG_LEN. Both forms appear to work fine on Linux, FreeBSD,
// NetBSD, but OpenBSD appears to have a bug, discussed here:
- // http://www.archivum.info/mailing.openbsd.bugs/2009-02/00017/
- // kernel-6080-msg_controllen-of-IPV6_PKTINFO.html
+ // https://marc.info/?l=openbsd-bugs&m=123485913417684&w=2
// which causes sendmsg to return EINVAL if the CMSG_LEN is
// used to set the msg_controllen value.
m.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo));