Date: Wed, 19 Aug 2009 09:50:24 -0700 From: "Li, Qing" <qing.li@bluecoat.com> To: "Denis Ahrens" <denis@h3q.com>, <freebsd-current@freebsd.org> Subject: RE: network problems Message-ID: <B583FBF374231F4A89607B4D08578A430467367F@bcs-mail03.internal.cacheflow.com> References: <18104823-CB3F-42DA-9DE8-E6692D81E96B@h3q.com>
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> > The problems are similar to = http://lists.freebsd.org/pipermail/freebsd-current/2009-August/010287.htm= l > That was a configuration issue. >=20 > When I try to ping the address the machine panics! > (something with sin_family and in_lltable_lookup) > http://denisy.dyndns.org/panic.jpg > After a quick cursory read over the code, this issue appears to be a = problem=20 in the flow-table handling logic in ip_output() function. Two problems seem to exist in the flow-table logic. 1. In flowtable_lookup() where it searches for the destination in the=20 routing table, the code does not check for the rt_ifp type once a route entry is found. In the case of "if_tun", the flow-table=20 must not try to cache any entry whose "rt_ifp->if_flag & = IFF_POINTOPOINT" is true. Right now it does, and I think this will trigger the crash later. 2. The flowtable_lookup() seems to alway assume a valid entry=20 will be returned as long as a route entry exists for the destination. In other words, if a route exists for the destination, then either flow-table already have a cache, or a new entry is created. This does not work due to (1.) above.=20 flowtable_lookup() should allow a "bypass flow-table" return, not=20 just success/failure result. This is especially true for tunneling interfaces "if_tun, if_gre" etc. where ip_output() will be called multiple times (nested). Only at the final = invocation of ip_output() (where the rt->rt_ifp points to a physical NIC) should a flow-table entry be created. So for now, as a possible temporary workaround, disable FLOWTABLE in = your kernel configuration file and see if that fixes the problem. -- Qing
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