On May 15, 1:33 pm, Rick Jones <rick.jon...@hp.com> wrote:

> True, although one still wouldn't use a "TCP" or "UDP" socket as the
> OP is asking. It could be an "ICMP" socket. I guess the BSD folks
> thought that the number of user-level uses of ICMP were few and far
> enough between to not warrant anything besides raw sockets. (Wild
> guess on my part)

I think another issue was one of policy. I don't think they wanted to
implement an ICMP access policy in the kernel. That meant any process
that was going to do anything with ICMP had to be root. So there was
really no advantage to a formal ICMP interface. One of the main
reasons we need a TCP and a UDP interface is to prohibit non-root
processes from stepping on each others' toes.

DS