Hi Rao,

>    The options described here apply to both 3SOCKET and 3XNET
>    interfaces.  Only 3XNET interfaces, though, have the ancillary data
>    feature.

I'm sure it's implied, but could you confirm that this will be fully
supported for TLI/TPI endpoints? This would provide an elegant fix for
4300326 and similar bugs in RPC apps.

>    The following IPPROTO_IP option may be set or retrieved as sticky
>    options with setsockopt/getsockopt or as ancillary data to a
>    sendmsg(3XNET) system call:
>
>      IP_PKTINFO          Set the source address and/or interface out
>                                    which the packet(s) will be sent.
Takes a
>                                    struct in4_pktinfo as the parameter.

No strong feeling about the option name, but I would say this: it would be
great to see such an API become a standard in the future. So you should try
and make it "standard-ready" from the start - if, for example, the name
conflict between Solaris and Linux is going to give headaches to the
standard bodies, use a different name.

> Other things not implemented (but that might have been expected):
>
>      We will not be extending the existing IPV6_PKTINFO feature to
>      cover IPv4 packets using IPv4-mapped addresses.  There are many
>      things that just don't work with IPv4-mapped addresses (such as
>      multicast), that render this old transition mechanism unsuitable
>      for anything but the most trivial of stand-alone services.  Thus,
>      we will instead update the documentation to let customers know
>      that they should open multiple sockets (using the IPV6_V6ONLY
>      option) instead, and use inetd's built-in multiple-socket support
>      when possible, and should not rely on robust v4mapped extensions.

I'll confess that I really like IPv4-mapped addresses, precisely because
they solve the UDP source address issue transparently, without having to
mess about with ancillary data. (The __sin6_src_id field in sockaddr_in6
that makes this work is only present on Solaris, however.) So you wouldn't
have to use IPV6_PKTINFO to specify the source address with IPv4-mapped
addresses anyway. Save the ::ffff :-)

Okay, time to crawl back to my (microsoft-powered) cage.

Blaise

_______________________________________________
networking-discuss mailing list
[email protected]

Reply via email to