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1 | -- ########################################################################### | |
2 | -- # proto_foo.lua | |
3 | -- | |
4 | -- Consider the Foo Protocol, which consists of only the Foo Packet defined as: | |
5 | -- | |
6 | -- Byte Offset Len Desc | |
7 | -- 0 4 32-bit unsigned integer | |
8 | -- 4 8 ASCII string (zero-padded) | |
9 | -- 12 5 byte array | |
10 | -- 17 4 IPv4 address | |
11 | -- | |
12 | -- Foo operates on UDP port 3456, but this port is configurable from Foo's preferences. | |
13 | -- This Wireshark Lua script implements this example protocol. | |
14 | -- ########################################################################### | |
15 | local _curport = nil -- current port under which this protocol is registered | |
16 | local MIN_LEN = 21 -- min buffer length (21 = 4+8+5+4) | |
17 | local DEFAULT_PORT = 3456 | |
18 | ||
19 | -- 1. Declare the protocol with the Proto() function. | |
20 | local proto_foo = Proto("foo", "Foo Protocol") | |
21 | ||
22 | -- 2. Declare the protocol's fields with the ProtoField.XXX() functions. | |
23 | proto_foo.fields.num = ProtoField.uint32("foo.num", "Unsigned integer (32-bit)") | |
24 | proto_foo.fields.str = ProtoField.stringz("foo.str", "Null-terminated string") | |
25 | proto_foo.fields.bytes = ProtoField.bytes("foo.bytes", "Byte array") | |
26 | proto_foo.fields.ip = ProtoField.ipv4("foo.ip", "IPv4 address") | |
27 | ||
28 | -- 3. (OPTIONAL) Declare the protocol's preferences with the Pref.XXX() functions. | |
29 | proto_foo.prefs.port = Pref.uint("Port", DEFAULT_PORT, "UDP port number") | |
30 | ||
31 | -- 4. Declare the protocol's dissector function | |
32 | function proto_foo.dissector(buf, pinfo, tree) | |
33 | ||
34 | if buf:len() >= MIN_LEN then | |
35 | pinfo.cols.protocol = "FOO" | |
36 | local offset = 0 | |
37 | local f = proto_foo.fields | |
38 | local subtree = tree:add(proto_foo, buf()) | |
39 | subtree:add(f.num , buf(offset, 4)); offset = offset + 4 | |
40 | subtree:add(f.str , buf(offset, 8)); offset = offset + 8 | |
41 | subtree:add(f.bytes , buf(offset, 5)); offset = offset + 5 | |
42 | subtree:add(f.ip , buf(offset, 4)); offset = offset + 4 | |
43 | end | |
44 | end | |
45 | ||
46 | -- 5. (OPTIONAL) Declare the protocol's init function. If this function is omitted, | |
47 | -- perform the protocol registration outside of it. | |
48 | function proto_foo.init() | |
49 | ||
50 | -- 6. Register the protocol with a DissectorTable (TCP port in this case) | |
51 | local dt = DissectorTable.get("tcp.port") | |
52 | if _curport then dt:remove(_curport, proto_foo) end | |
53 | dt:add(proto_foo.prefs.port, proto_foo) | |
54 | _curport = proto_foo.prefs.port | |
55 | end | |
56 | ||
57 | -- XXX: do init here if proto_foo.init() does not exist. This file can | |
58 | -- only ever be loaded once (no way to undeclare a Proto), so no need | |
59 | -- to remove this dissector from a previously registered dissector table. | |
60 | --DissectorTable.get("udp.port"):add(proto_foo.prefs.port, proto_foo) |