Date: Tue, 13 Jan 2004 13:49:37 -0800 (PST) From: Mike Hibler <mike@cs.utah.edu> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/61336: traceroute doesn't work with more than 85 hops Message-ID: <200401132149.i0DLnb7v036897@www.freebsd.org> Resent-Message-ID: <200401132150.i0DLoLkg033809@freefall.freebsd.org>
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>Number: 61336 >Category: misc >Synopsis: traceroute doesn't work with more than 85 hops >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Jan 13 13:50:21 PST 2004 >Closed-Date: >Last-Modified: >Originator: Mike Hibler >Release: 4.7-RELEASE >Organization: University of Utah >Environment: >Description: Any combination of (nhops * nprobes per hop) > 255 will fail due to a sequence number placed in the packet as 8-bits but kept internally as 32-bits. So comparison of what comes back in the packet (8-bits) with the internal counter (32-bits) fails. With the default of 3 probes per hop, 85 * 3 == 255. I know, I know, who gives a .... :-) >How-To-Repeat: Traceroute a host 86 hops away! >Fix: Ensure that the "check" performed upon reply only uses 8-bits of sequence, as the "prepare" function does implicitly by using outdata->seq 1060c1060 < && (*proto->check)((u_char *)icp,seq)) --- > && (*proto->check)((u_char *)icp, (u_char)seq)) 1072c1072 < && (*proto->check)(inner, seq)) --- > && (*proto->check)(inner, (u_char)seq)) >Release-Note: >Audit-Trail: >Unformatted:
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