[En-Nut-Discussion] bug in ipin.c ?!

llsoft at quantentunnel.de llsoft at quantentunnel.de
Fri Jul 7 18:43:23 CEST 2006

Hi *,

one month ago I already posted this article. However, I am still not satisfied with the reply. Maybe I have more luck this time.

I think I found a bug in "ipin.c". If it is really a bug maybe many problems using ethernut in big networks may be solved.

In function NutIpInput an ICMP response 'unreachable protocol' is sent if the protocol is unknown.
According to RFC 1122, section 3.2.2, no icmp response should be sent if destination address was broadcast or multicast.

Proposed solution:

Therefore, almost at the end of the function "NutIpInput(...)", the line before freeing the net buffer

 if (!NutIcmpResponse(ICMP_UNREACH, ICMP_UNREACH_PROTOCOL, 0, nb))

should be changed to

 if (bcast || !NutIcmpResponse(ICMP_UNREACH, ICMP_UNREACH_PROTOCOL, 0, nb))



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