On Fri, 13 Apr 2007 18:10:12 +0200 Daniel Schaffrath <[EMAIL PROTECTED]> wrote: > > On 2007/04/12 , at 20:19, Eric Dumazet wrote: > > > > Warning : tcpdump can lie, telling you packets being transmited > > several time. > Maybe you have further pointers how come that tcpdump lies about > duplicated packets? >
dev_queue_xmit_nit() is called before attempting to send packet to device. If device could not accept the packet (hard_start_xmit() returns an error), packet is requeued and retried later. each retry means call ev_queue_xmit_nit() again, so tcpdump/sniffers can 'see' packet transmited several times. This is why I asked for "tc -s -d qdisc" results : to check the requeue counter (not its absolute value, but relative to number of packets sent) See dev_hard_start_xmit() in net/core/dev.c - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
