Dear Experts,
I am building my Lua plugin for Wireshark, but I got a failed assertion below:
[Dissector bug, protocol TCP: /build/wireshark-rjGTDh/wireshark-2.6.3/epan/dissectors/packet-tcp.c:5591: failed assertion "save_desegment_offset == pinfo->desegment_offset && save_desegment_len == pinfo->desegment_len"]
Our prorotocol is top on TCP and has a length code in. so I want to get enough bytes for my dissector.
At first, I use pinfo.desegment_len = missing_bytes and return nothing, but got the assertion.
Now, I am using dissect_tcp_pdus, still got the problem.
I attach my code below and look forward to your reply.
Thank you very much and sorry to bother you.
Here is my code:
local neop2p = Proto("NEO", "Neo P2P Protocol")
neop2p.fields.magic = ProtoField.uint32("neop2p.magic", "MAGIC", base.DEC, NET_TYPE)
neop2p.fields.cmd = ProtoField.string("neop2p.cmd", "COMMAND", base.UNICODE)
neop2p.fields.length = ProtoField.uint32("neop2p.length", "LENGTH", base.DEC)
neop2p.fields.checksum = ProtoField.uint32("neop2p.checksum", "CHECKSUM", base.DEC)
neop2p.fields.payload = ProtoField.string("neop2p.payload", "PAYLOAD", base.ASCII)
local function neop2p_dissector(buffer, pinfo, tree)
local L = buffer:len()
local magic = buffer(0, 4):le_uint()
local cmd = buffer(4, 12):stringz()
local length = buffer(16, 4):le_uint()
local p2p_tree = tree:add(neop2p, buffer(0, L), "Neo P2P Protocol, "..NET_TYPE[magic])
pinfo.cols.protocol:set("NEO")
pinfo.cols.info:set("".. NET_TYPE[magic]..","..cmd)
local offset = 0
p2p_tree:add(neop2p.fields.magic, buffer(offset, 4), buffer(offset, 4):le_uint64():tonumber())
offset = offset + 4
p2p_tree:add(neop2p.fields.cmd, buffer(offset, 12), buffer(offset, 12):string())
offset = offset + 12
p2p_tree:add(neop2p.fields.length, buffer(offset, 4), buffer(offset, 4):le_uint64():tonumber())
offset = offset + 4
p2p_tree:add(neop2p.fields.checksum, buffer(offset, 4), buffer(offset, 4):le_uint64():tonumber())
offset = offset + 4
if length ~= 0 then
local payload = buffer(offset, length)
p2p_tree:add(neop2p.fields.payload, payload, tostring(payload))
offset = offset + length
end
-- if cmd == C_INV then
-- return neop2p_inv_dissector(payload, pinfo, p2p_tree)
-- end
-- if cmd == C_ADDR then
-- return neop2p_addr_dissector(payload, pinfo, p2p_tree)
-- end
-- if cmd == C_GET_DATA then
-- return neop2p_getdata_dissector(payload, pinfo, p2p_tree)
-- end
-- if cmd == C_VERSION then
-- return neop2p_ver_dissector(payload, pinfo, p2p_tree)
-- end
-- if cmd == C_GET_HEADERS then
-- return neop2p_getheaders_dissector(payload, pinfo, p2p_tree)
-- end
return true
end
local function get_neop2p_len(buffer)
local len = buffer(16, 4):le_uint() + 24
return len
end
local neo = Proto("NEOPROTOCOL", "Neo Protocol")
function neo.dissector(buffer, pinfo, tree)
dissect_tcp_pdus(buffer, tree, 24,
get_neop2p_len, neop2p_dissector)
return true
end
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neo:register_heuristic("tcp", neo.dissector)
