Re: IP_PKTINFO, sendmsg(2) and routing.

[Tom Ivar Helbekkmo <tih%hamartun.priv.no@localhost>]

Roy Marples <roy%marples.name@localhost> writes:

> https://nxr.netbsd.org/xref/src/sys/netinet/ip_output.c#1167

Ah, yes, that bit is somewhat simplistic, too.  Back when I worked on
this code, the "what if an interface is specified, but no source
address?" question got rather short shrift.  It'll be good to get back
to it, and have a more complete implementation.

> But, in a nutshell, the most basic multi-homed implementation is the
> DHCP client. IP_PKTINFO allows us NOT to need BPF. We should be able
> to send from the unspecified address to the broadcast address on a
> specific interface using IP_PKTINFO for the DHCP_DISCOVER message.

I'll try to implement this in a way that as far as possible maintains
compatibility with our existing implementation, Linux, and Solaris, and
orthogonality with the standard for IPv6, as described in RFC3542.  :)

I plan to have running code some time during the coming weekend; I'm
going to the cabin for a couple of days' relaxation, so this is perfect.

-tih
-- 
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