From a8a54197fa14aa65846edd4ffc186d811dd7f583 Mon Sep 17 00:00:00 2001
From: Maarten de Vries <maarten@de-vri.es>
Date: Mon, 24 Jan 2022 13:21:29 +0100
Subject: [PATCH] Add wireshark dissector for TCP and UDP transports.

---
 CHANGELOG               |  1 +
 wireshark/README.md     | 10 +++++
 wireshark/fizyr-rpc.lua | 94 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 wireshark/README.md
 create mode 100644 wireshark/fizyr-rpc.lua

diff --git a/CHANGELOG b/CHANGELOG
index a777ec2..450d611 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -3,6 +3,7 @@
 - [fix][minor] Remove the `Sized` restriction for the `EncodeBody` trait.
 - [impl][patch] Use `poll_write_vectored` in the TCP transport to write the header and body with a single syscall.
 - [rename][major] Rename `crate::util::format` module to `crate::format`.
+- [add][patch] Add Wireshark dissector for TCP and UDP transports for easier debugging.
 
 # Version 0.5.0-alpha7 - 2022-01-10
 - [add][minor] Add a specific `Format` trait for generated interaces to avoid writing overly long trait bounds.
diff --git a/wireshark/README.md b/wireshark/README.md
new file mode 100644
index 0000000..f2d85dd
--- /dev/null
+++ b/wireshark/README.md
@@ -0,0 +1,10 @@
+# Wireshark dissector
+
+This folder contains a Wireshark dissector for the Fizyr RPC protocol.
+Copy the `fizyr-rpc.lua` file to your Wireshark plugin directory to install it.
+See [the Wireshark manual][wireshark-plugin-folder] for more information on the plugin folder.
+
+Afterwards, either restart Wireshark or select the "Reload LUA plugins" option from the "Analyze" menu.
+You should now be able to activate the dissector from "Decode As ..." dialog from the "Analyze" menu.
+
+[wireshark-plugin-folder]: https://www.wireshark.org/docs/wsug_html_chunked/ChPluginFolders.html
diff --git a/wireshark/fizyr-rpc.lua b/wireshark/fizyr-rpc.lua
new file mode 100644
index 0000000..d1d101b
--- /dev/null
+++ b/wireshark/fizyr-rpc.lua
@@ -0,0 +1,94 @@
+do
+	local fizyr_rpc_tcp_proto = Proto("fizyr_rpc_tcp", "Fizyr RPC over TCP");
+	local fizyr_rpc_udp_proto = Proto("fizyr_rpc_udp", "Fizyr RPC over UDP");
+
+	local udp_length = Field.new("udp.length");
+
+	local field_length = ProtoField.uint32(
+		"fizyr_rpc.message_length",
+		"Message length",
+		base.DEC,
+		nil,
+		nil,
+		"The length of the message, excluding the message length itself."
+	)
+
+	local field_kind = ProtoField.uint32(
+		"fizyr_rpc.message_type",
+		"Message type",
+		base.DEC,
+		{
+			[0] = "Request",
+			[1] = "Response",
+			[2] = "RequestUpdate",
+			[3] = "ResponseUpdate",
+			[4] = "Stream",
+		},
+		nil,
+		"The type of the RPC message: Request, Response, RequestUpdate, ResponseUpdate or Stream."
+	)
+
+	local field_request_id = ProtoField.uint32(
+		"fizyr_rpc.request_id",
+		"Request ID",
+		base.DEC,
+		nil,
+		nil,
+		"The request ID of the message. Not used for stream messages."
+	)
+
+	local field_service_id = ProtoField.int32(
+		"fizyr_rpc.service_id",
+		"Service ID",
+		base.DEC,
+		nil,
+		nil,
+		"The service ID of the message."
+	)
+
+	local field_body = ProtoField.bytes(
+		"fizyr_rpc.body",
+		"Message body",
+		base.SPACE,
+		"The message body/payload."
+	)
+
+	fizyr_rpc_tcp_proto.fields = {
+		field_length,
+		field_kind,
+		field_request_id,
+		field_service_id,
+		field_body,
+	}
+
+	function fizyr_rpc_tcp_proto.dissector(buffer, pinfo, tree)
+		dissect_tcp_pdus(buffer, tree, 4, fizyr_rpc_tcp_get_length, fizyr_rpc_tcp_dissect_reassembled)
+	end
+
+	function fizyr_rpc_tcp_get_length(buffer, pinfo, offset)
+		return 4 + buffer(0, 4):le_uint()
+	end
+
+	function fizyr_rpc_tcp_dissect_reassembled(buffer, pinfo, tree)
+		local subtree = tree:add(fizyr_rpc_tcp_proto, buffer)
+		subtree:add_le(field_length,     buffer(0, 4))
+		subtree:add_le(field_kind,       buffer(4, 4))
+		subtree:add_le(field_request_id, buffer(8, 4))
+		subtree:add_le(field_service_id, buffer(12, 4))
+		subtree:add_le(field_body, buffer(16))
+	end
+
+	function fizyr_rpc_udp_proto.dissector(buffer, pinfo, tree)
+		subtree:add_le(field_length,     udp_length())
+		subtree:add_le(field_kind,       buffer(0, 4))
+		subtree:add_le(field_request_id, buffer(4, 4))
+		subtree:add_le(field_service_id, buffer(8, 4))
+		subtree:add_le(field_body, buffer(12))
+	end
+
+	local tcp_table = DissectorTable.get("tcp.port")
+	tcp_table:add("1-65535", fizyr_rpc_tcp_proto)
+
+	local udp_table = DissectorTable.get("udp.port")
+	udp_table:add("1-65535", fizyr_rpc_udp_proto)
+end