socket() returned EPROTONOSUPPORT for every socket type it does not create.
FreeBSD 11.4's socreate returns EPROTOTYPE when no protocol is found, the
protocol is 0 and the type is not 0, and EPROTONOSUPPORT when a protocol was
given. Its inet domain (in_proto.c) has SOCK_RAW entries in every kernel and
a SOCK_SEQPACKET entry only with SCTP, and no SOCK_RDM or other type.
Return EPROTOTYPE for a type the inet domain never has, such as SOCK_RDM,
with protocol 0. SOCK_RAW and SOCK_SEQPACKET keep EPROTONOSUPPORT, since
whether the console creates them is not known. Test the unknown types and
mismatched protocols for AF_INET and AF_INET6, and list the socket types and
families that are not created in the library's technical debt file.
Written with AI assistance (Claude).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
