Hi,

I was chasing an interesting problem in our FreeBSD 4.3 codebase today.

Broadcast IP datagrams were not being received by programs on the same 
system the IP datagrams were sent from. They were making it out the wire.

The were being sent on a Broadcom GigE interface that has hardware 
checksumming. 

After a while we realized that what was happening was that the packets 
were being marked for hardware checksumming in ip_output 
(m->m_pkthdr.csum_flags), but the decision about looping a packet back to 
ourselves is made in ether_output, so the packet is never checksummed and 
is discarded in ip_input.

Has this been fixed in a subsequent release?

Also, why is the decision to loop the packet back made in ether_output 
rather than in ip_output? Off the top of my head I can't see any 
particular advantage, but perhaps there is. The disadvantage is that I 
will have to disable hardware assist for broadcast packets to make things 
work right.
 
Regards
-----
Richard Sharpe, [EMAIL PROTECTED], [EMAIL PROTECTED], 
[EMAIL PROTECTED]


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