Re: REDIRECT changes DST address of the packet

[Patrick McHardy <kaber@trash.net>]

KOVACS Krisztian wrote:

>   Patrick, I'm afraid this is not enough for a full-featured UDP
> solution. If you're using a single socket to receive UDP packets sent to
> multiple original addresses this approach simply fails. A better
> solution would require receiving the original destination address in a
> per-packet manner.

You're right, it doesn't work for unconnected sockets. I'm looking into
other possibilities now. I'm thinking of something similar to
SIOCGSTAMP - altough this would require increasing the size of struct
sock.

>   We're using something similar as part of the transparent proxying
> patchset, but unfortunately this requires enlarging the skb and is a
> little hackish. The patch introduces an IP_RECVORIGADDRS socket option.
> If you enable this sockopt on a UDP socket, then recvmsg() will return
> the original addresses as a control message.

Why does the skb need to be enlarged?

Regards
Patrick