IPPROTO_DIVERT and PF_INET6

[JINMEI Tatuya / 神明達哉]

At Sat, 3 May 2008 20:00:43 +1000,
Edwin Groothuis <edwin at mavetju.org> wrote:

> Before somebody shoots me down on it: I know that ipfw_divert() is
> not suitable for IPv6 packets.

[snip]

> which is what I expected. So why doesn't this get displayed for the
> IPv6 sockets?

I don't know much about IPDIVERT, but it seems to me this is simply
because the IPv6 stack (sys/netinet6) doesn't support divert sockets.
So opening an AF_INET6 socket with the protocol being IPPROTO_DIVERT
(which is "unknown")

        sin = socket(PF_INET6, SOCK_RAW, IPPROTO_DIVERT);

matches a wildcard protosw

/* raw wildcard */
{
	.pr_type =		SOCK_RAW,
	.pr_domain =		&inet6domain,
	.pr_flags =		PR_ATOMIC|PR_ADDR,
	.pr_input =		rip6_input,
	.pr_output =		rip6_output,
	.pr_ctloutput =		rip6_ctloutput,
	.pr_usrreqs =		&rip6_usrreqs
},

whose pr_protocol is implicitly set to 0, which is (accidentally)
interpreted by lsof as "HOPOPTS".

This should provide a direct answer to you question of "why"?  But I
suspect the underlying question is why divert sockets aren't supported
for IPv6.  I don't know why.

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.