[Click] IPRewriter and ICMP packets

[Eddie Kohler]

Erik VandeKieft wrote:
> I noticed that ICMP packets that enter an IPRewriter element disappear and
> don't make it out any of the outputs. What happens to them, are they
> dropped on the floor? Why?
> 
> I know that there is a seperate ICMPRewriter class, but I that only seems
> to rewrite the packet contents, not the actual IP headers. I need to
> rewrite the source and destinations of ICMP packets, including pings, and
> ICMPPingRewriter only allows you to do it for one static source and
> destination, whereas I need it to be dynamic based on an IPRewriter's
> table.
> 
> Do I need to implement this myself or can click already accomplish this?

Can you be more clear about what semantics you want here?  IPRewriter is a NAPT 
(network address/port translator), so it requires port numbers on its input 
packets.  ICMP ping packets don't have ports.

The ICMPRewriter class *does* rewrite packet headers as well as packet contents, 
or at least it should.  But it only applies to error packets (i.e. not pings).

Eddie