Ethereal-dev: [Ethereal-dev] Cisco PVSTP+ BPDUs

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From: "Clinton Work" <clinton@xxxxxxxxxxx>
Date: Mon, 12 Apr 2004 14:18:18 -0600
Could one of the maintainers apply the following patch to packet-bpdu.c? The
patch adds basic support for
the Cisco PVSTP+ BPDUs (Per Vlan Spanning Tree). The PVSTP+ BPDUs are
identical to regular ones
except for a few differences
  a) The packets use a LLC SNAP header with a Cisco PID value of 0x010b
  b) The packets are sent to multicast MAC 01:00:0c:cc:cc:cd
  c) At the end of the BPDU there is some padding plus a TLV indicating the
VLAN which the BPDU is for
       Padding (2 bytes)
       TLV format
           Type:  (2 bytes)  Only 0x00 is used right now to indicate the
PVID (Per Vlan ID)
           Length: (2 bytes)
           Value  (the PVID is 2 bytes long)

I have used the basic patch below for troubleshooting and verified that it
works properly. I haven't had time to code
an additional patch to decode the PVID TLV yet.

--- packet-bpdu.c       Thu Jan  8 20:12:20 2004
+++ packet-bpdu-pvstp.c Mon Apr 12 14:01:38 2004
@@ -824,4 +824,5 @@
   dissector_add("llc.dsap", SAP_BPDU, bpdu_handle);
   dissector_add("ppp.protocol", PPP_BPDU, bpdu_handle);
   dissector_add("chdlctype", CHDLCTYPE_BPDU, bpdu_handle);
+  dissector_add("llc.cisco_pid", 0x010b, bpdu_handle);
 }


=========================================================================
Clinton Work                                        clinton@xxxxxxxxxxx
Calgary, Alberta