T.62: Add dissection of parameters; make tree hierarchical

1 files changed, 50 insertions, 11 deletions

diff --git a/t62.lua b/t62.lua
index c594a21..2126631 100644
--- a/t62.lua
+++ b/t62.lua
@@ -74,7 +74,9 @@ local session_pi_pgi_names = {
 	[0xe7] = "Private use 7",
 	[0xe8] = "Non-standardixed capabilities",
 }
-local hf_session_pi_pgi = ProtoField.uint8("t64.session.pi", "Parameter (Group) Identifier", base.HEX, session_pi_pgi_names)
+local hf_session_pi_pgi = ProtoField.uint8("t62.session.pi", "Session Parameter (Group) Identifier", base.HEX, session_pi_pgi_names)
+local hf_session_pli = ProtoField.uint8("t62.session.pli", "Session Parameter (Group) Length Identifier", base.DEC)
+local hf_session_pdata = ProtoField.bytes("t62.session.pdata", "Session Parameter Data")
 
 local doc_cri_names_long = {
 	-- Table 5/T.62: CRI for document command identifiers
@@ -114,6 +116,7 @@ local doc_cri_names = {
 	[0x3e] = "RDCLP",
 	[0x00] = "RDGR",
 }
+local hf_session_param = ProtoField.none("t62.session.param", "Document Parameter")
 local hf_document_cri = ProtoField.uint8("t62.document.cri", "Command/Response Identifier", base.HEX, doc_cri_names)
 local hf_document_li = ProtoField.uint8("t62.document.li", "Length Identifier", base.DEC)
 
@@ -160,7 +163,10 @@ local doc_pi_pgi_names = {
 	[0xe7] = "Private use 7",
 	[0xe8] = "Non-standardized capabilities",
 }
-local hf_doc_pi_pgi = ProtoField.uint8("t64.document.pi", "Parameter (Group) Identifier", base.HEX, doc_pi_pgi_names)
+local hf_doc_param = ProtoField.none("t62.document.param", "Document Parameter")
+local hf_doc_pi_pgi = ProtoField.uint8("t62.document.pi", "Document Parameter (Group) Identifier", base.HEX, doc_pi_pgi_names)
+local hf_doc_pli = ProtoField.uint8("t62.document.pli", "Document Parameter (Group) Length Identifier", base.DEC)
+local hf_doc_pdata = ProtoField.bytes("t62.document.pdata", "Document Parameter Data")
 
 -- 5.7.2.10 Reason (session or document)
 local reason_names = {
@@ -193,34 +199,63 @@ local teletex_page_format_names = {
 }
 
 t62_protocol.fields = {
-	hf_session_cri, hf_session_li, hf_session_pi_pgi,
-	hf_document_cri, hf_document_li, hf_doc_pi_pgi,
+	hf_session_cri, hf_session_li,
+	hf_session_param, hf_session_pi_pgi, hf_session_pli, hf_session_pdata,
+	hf_document_cri, hf_document_li,
+	hf_doc_param, hf_doc_pi_pgi, hf_doc_pli, hf_doc_pdata,
 	hf_document_data,
 }
 
+function decode_one_session_pi_pgi(buffer, offset, pinfo, tree)
+	local pi = buffer(offset, 1):uint()
+	local p_li = buffer(offset+1, 1):uint()
+	local subtree = tree:add(hf_session_param, buffer(offset, 2+p_li))
+	subtree:append_text(" " .. session_pi_pgi_names[pi])
+	subtree:add(hf_session_pi_pgi, buffer(offset, 1))
+	subtree:add(hf_session_pli, buffer(offset+1, 1))
+	subtree:add(hf_session_pdata, buffer(offset+2, p_li))
+	return 2 + p_li
+end
+
+function decode_one_doc_pi_pgi(buffer, offset, pinfo, tree)
+	local pi = buffer(offset, 1):uint()
+	local p_li = buffer(offset+1, 1):uint()
+	local subtree = tree:add(hf_doc_param, buffer(offset, 2+p_li))
+	subtree:append_text(" " .. doc_pi_pgi_names[pi])
+	subtree:add(hf_doc_pi_pgi, buffer(offset, 1))
+	subtree:add(hf_doc_pli, buffer(offset+1, 1))
+	subtree:add(hf_doc_pdata, buffer(offset+2, p_li))
+	return 2 + p_li
+end
+
 function decode_t62_document(buffer, pinfo, tree)
 	local d_cri = buffer(0, 1):uint()
 	local d_li = buffer(1, 1):uint()
+	local subtree = tree:add(t62_protocol, buffer(), "T.62 Document")
 
 	pinfo.cols.info:append(" " .. doc_cri_names[d_cri])
-	tree:append_text(" " .. doc_cri_names[d_cri] .. "(" .. doc_cri_names_long[d_cri] .. ")")
-	tree:add(hf_document_cri, buffer(0, 1))
-	tree:add(hf_document_li, buffer(1, 1))
+	subtree:append_text(" " .. doc_cri_names[d_cri] .. " (" .. doc_cri_names_long[d_cri] .. ")")
+	subtree:add(hf_document_cri, buffer(0, 1))
+	subtree:add(hf_document_li, buffer(1, 1))
 
+	-- document parameters
 	if (d_li > 0) then
-		-- FIXME: document parameters
+		local offset = 2
+		while (offset <= buffer:len() and offset - 2 < d_li) do
+			offset = offset + decode_one_doc_pi_pgi(buffer, offset, pinfo, subtree)
+		end
 	end
 
 	-- user data only exists in CDUI
 	if (d_cri == 0x01) then
-		tree:add(hf_document_data, buffer(2))
+		subtree:add(hf_document_data, buffer(2))
 	end
 end
 
 function t62_protocol.dissector(buffer, pinfo, tree)
 	pinfo.cols.protocol = t62_protocol.name
 
-	local subtree = tree:add(t62_protocol, buffer(), "T.62")
+	local subtree = tree:add(t62_protocol, buffer(), "T.62 Session")
 	local offset = 0
 
 	local s_cri = buffer(0, 1):uint()
@@ -232,7 +267,11 @@ function t62_protocol.dissector(buffer, pinfo, tree)
 	subtree:add(hf_session_li, buffer(1, 1))
 
 	if (s_li > 0) then
-		-- FIXME: session parameters
+		-- session parameters
+		local offset = 2
+		while (offset <= buffer:len() and offset - 2 < s_li) do
+			offset = offset + decode_one_session_pi_pgi(buffer, offset, pinfo, subtree)
+		end
 	end
 
 	-- document layer data only exists in CSUI / RSUI