[Xorp-hackers] Assert with multicast routing in fea, pif_index collision with "register_vif"

[Ben Greear]

I am working on adding support for multiple multicast routing tables to 
Linux & Xorp.
I think I have it mostly implemented, but I'm still in heavy debugging....

Today, I got to the point where I was getting an assert in FEA due to 
what appears
to be a vif-index collision:

[ 2008/06/04 17:48:50 INFO xorp_fea MFEA ] Interface enabled Vif[rddVR2] 
pif_index: 6 vif_index: 2 addr: 3.3.3.3 subnet: 3.3.3.0/24 broadcast: 
3.3.3.255 peer: 0.0.0.0 Flags: MULTICAST BROADCAST UNDERLYING_VIF_UP 
MTU: 1500 DOWN IPv4 ENABLED
[ 2008/06/04 17:48:50 INFO xorp_fea MFEA ] Interface started: 
Vif[rddVR2] pif_index: 6 vif_index: 2 addr: 3.3.3.3 subnet: 3.3.3.0/24 
broadcast: 3.3.3.255 peer: 0.0.0.0 Flags: MULTICAST BROADCAST 
UNDERLYING_VIF_UP MTU: 1500 UP IPv4 ENABLED
[ 2008/06/04 17:48:50 INFO xorp_fea MFEA ] Interface added: 
Vif[register_vif] pif_index: 6 vif_index: 3 addr: 3.3.3.3 subnet: 
3.3.3.3/32 broadcast: 3.3.3.3 peer: 0.0.0.0 Flags: PIM_REGISTER 
UNDERLYING_VIF_UP MTU: 1500
[ 2008/06/04 17:48:50  FATAL xorp_fea:5016 FEA iftree.cc:1673 
insert_ifindex ] Assertion (iter->second == ifp) failed


The 'register_vif' interface has same pif_index, so it hits this assert 
if iftree.cc
(well, I'm running my own patches in fea, so that *could* be the 
problem, but
the code below is from the official tree, and looks like it would have 
the same problem.)

Any ideas on this?  I can paste my entire xorp config if someone is 
interested...

void
IfTree::insert_ifindex(IfTreeInterface* ifp)
{
    IfIndexMap::iterator iter;

    XLOG_ASSERT(ifp != NULL);

    if (ifp->pif_index() == 0)
        return;         // Ignore: invalid pif_index

    iter = _ifindex_map.find(ifp->pif_index());
    if (iter != _ifindex_map.end()) {
        XLOG_ASSERT(iter->second == ifp);  /// This is what hits  ///
        iter->second = ifp;
        return;
    }

    _ifindex_map[ifp->pif_index()] = ifp;
}


-- 
Ben Greear <greearb at candelatech.com> 
Candela Technologies Inc  http://www.candelatech.com