dissect-wireshark: Add support for dissecting PPP frames

This commit also fixes Info column output: before this change, the
column was showing KeyLocator name for data packets, instead of name of
the data packet.

Change-Id: I742d943662916072b1f08ff6050564ff34a698b4

tools/dissect-wireshark/README.md

@@ -17,6 +17,8 @@ supported in the following cases:
 
 - NDN packets are encapsulated in Ethernet frames with EtherType 0x8624.
 
+- NDN packets are encapsulated in PPP frames with protocol type 0x0077.
+
 ## Available dissection features
 
 - When UDP packet is fragmented, the dissection is performed after the full IP reassembly.

tools/dissect-wireshark/ndn.lua

@@ -477,7 +477,7 @@ function ndn.dissector(tvb, pInfo, root) -- Tvb, Pinfo, TreeItem
             pktType = "Nack"
          end
 
-         if pktName == "" and block.type == 7 then
+         if block.type == 7 then
             pktName = getUriFromName(block)
          end
       end
@@ -527,4 +527,7 @@ websocketDissectorTable:add("1-65535", ndn)
 local ethernetDissectorTable = DissectorTable.get("ethertype")
 ethernetDissectorTable:add(0x8624, ndn)
 
+local pppDissectorTable = DissectorTable.get("ppp.protocol")
+pppDissectorTable:add(0x0077, ndn)
+
 io.stderr:write("NDN dissector successfully loaded\n")