Re: [PATCH RESEND] 2.6.22.6 networking [ipv4]: fix wrong destination when reply packetes

Now icmp_reply is only called by icmp_echo and icmp_timestamp
ip_send_reply is only called by tcp_v4_send_reset and tcp_v4_send_ack

I think in all situations the ip_hdr(skb)->saddr is set and should
be the destination of reply packets.

If using rt->rt_src as destination is correct in some situation, 
can anyone give me a example? 

I think perhaps it is a copy and paste from code like
ip_build_and_send_pkt, but reply packets in these situations 
(icmp_echo and icmp_timestamp and tcp_v4_send_ack and tcp_v4_send_reset) 
is diffrent, I think we can just use ip_hdr(skb)->saddr as 
destination address.

On Thu, Sep 20, 2007 at 09:35:09PM -0700, David Stevens wrote:

I'm not sure why it's using rt_src here, but there are relevant cases that
your description doesn't cover. For example, what happens if  the source
is not set in the original packet?  Does NAT affect this?

You quote RFC text for ICMP echo and the case where the receiving machine
is the final destination, but you're modifying code that is used for all 
ICMP
types and used for ICMP errors generated when acting as an intermediate
router.

In ordinary cases, and certainly with ICMP echo when the source is set in
the original packet and no rewriting is going on (and the address is not 
spoofed),
using the original source as the destination is fine. But have you tested 
or
considered the other cases?

                                                +-DLS