mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-27 03:55:36 +00:00
169 lines
6.4 KiB
Lua
169 lines
6.4 KiB
Lua
function hasbit(x, p)
|
|
return x % (p + p) >= p
|
|
end
|
|
|
|
tsdebug_ll = Proto("tsdebug", "Tailscale debug")
|
|
PATH = ProtoField.string("tsdebug.PATH","PATH", base.ASCII)
|
|
SNAT_IP_4 = ProtoField.ipv4("tsdebug.SNAT_IP_4", "Pre-NAT Source IPv4 address")
|
|
SNAT_IP_6 = ProtoField.ipv4("tsdebug.SNAT_IP_6", "Pre-NAT Source IPv6 address")
|
|
DNAT_IP_4 = ProtoField.ipv4("tsdebug.DNAT_IP_4", "Pre-NAT Dest IPv4 address")
|
|
DNAT_IP_6 = ProtoField.ipv4("tsdebug.DNAT_IP_6", "Pre-NAT Dest IPv6 address")
|
|
tsdebug_ll.fields = {PATH, SNAT_IP_4, SNAT_IP_6, DNAT_IP_4, DNAT_IP_6}
|
|
|
|
function tsdebug_ll.dissector(buffer, pinfo, tree)
|
|
pinfo.cols.protocol = tsdebug_ll.name
|
|
packet_length = buffer:len()
|
|
local offset = 0
|
|
local subtree = tree:add(tsdebug_ll, buffer(), "Tailscale packet")
|
|
|
|
-- -- Get path UINT16
|
|
local path_id = buffer:range(offset, 2):le_uint()
|
|
if path_id == 0 then subtree:add(PATH, "FromLocal")
|
|
elseif path_id == 1 then subtree:add(PATH, "FromPeer")
|
|
elseif path_id == 2 then subtree:add(PATH, "Synthesized (Inbound / ToLocal)")
|
|
elseif path_id == 3 then subtree:add(PATH, "Synthesized (Outbound / ToPeer)")
|
|
elseif path_id == 254 then subtree:add(PATH, "Disco frame")
|
|
end
|
|
offset = offset + 2
|
|
|
|
-- -- Get SNAT address
|
|
local snat_addr_len = buffer:range(offset, 1):le_uint()
|
|
if snat_addr_len == 4 then subtree:add(SNAT_IP_4, buffer:range(offset + 1, snat_addr_len))
|
|
elseif snat_addr_len > 0 then subtree:add(SNAT_IP_6, buffer:range(offset + 1, snat_addr_len))
|
|
end
|
|
offset = offset + 1 + snat_addr_len
|
|
|
|
-- -- Get DNAT address
|
|
local dnat_addr_len = buffer:range(offset, 1):le_uint()
|
|
if dnat_addr_len == 4 then subtree:add(DNAT_IP_4, buffer:range(offset + 1, dnat_addr_len))
|
|
elseif dnat_addr_len > 0 then subtree:add(DNAT_IP_6, buffer:range(offset + 1, dnat_addr_len))
|
|
end
|
|
offset = offset + 1 + dnat_addr_len
|
|
|
|
-- -- Handover rest of data to lower-level dissector
|
|
local data_buffer = buffer:range(offset, packet_length-offset):tvb()
|
|
if path_id == 254 then
|
|
Dissector.get("tsdisco"):call(data_buffer, pinfo, tree)
|
|
else
|
|
Dissector.get("ip"):call(data_buffer, pinfo, tree)
|
|
end
|
|
end
|
|
|
|
-- Install the dissector on link-layer ID 147 (User-defined protocol 0)
|
|
local eth_table = DissectorTable.get("wtap_encap")
|
|
eth_table:add(wtap.USER0, tsdebug_ll)
|
|
|
|
|
|
local ts_dissectors = DissectorTable.new("ts.proto", "Tailscale-specific dissectors", ftypes.STRING, base.NONE)
|
|
|
|
|
|
--
|
|
-- DISCO metadata dissector
|
|
--
|
|
tsdisco_meta = Proto("tsdisco", "Tailscale DISCO metadata")
|
|
DISCO_IS_DERP = ProtoField.bool("tsdisco.IS_DERP","From DERP")
|
|
DISCO_SRC_IP_4 = ProtoField.ipv4("tsdisco.SRC_IP_4", "Source IPv4 address")
|
|
DISCO_SRC_IP_6 = ProtoField.ipv4("tsdisco.SRC_IP_6", "Source IPv6 address")
|
|
DISCO_SRC_PORT = ProtoField.uint16("tsdisco.SRC_PORT","Source port", base.DEC)
|
|
DISCO_DERP_PUB = ProtoField.bytes("tsdisco.DERP_PUB", "DERP public key", base.SPACE)
|
|
tsdisco_meta.fields = {DISCO_IS_DERP, DISCO_SRC_PORT, DISCO_DERP_PUB, DISCO_SRC_IP_4, DISCO_SRC_IP_6}
|
|
|
|
function tsdisco_meta.dissector(buffer, pinfo, tree)
|
|
pinfo.cols.protocol = tsdisco_meta.name
|
|
packet_length = buffer:len()
|
|
local offset = 0
|
|
local subtree = tree:add(tsdisco_meta, buffer(), "DISCO metadata")
|
|
|
|
-- Parse flags
|
|
local from_derp = hasbit(buffer(offset, 1):le_uint(), 0)
|
|
subtree:add(DISCO_IS_DERP, from_derp) -- Flag bit 0
|
|
offset = offset + 1
|
|
-- Parse DERP public key
|
|
if from_derp then
|
|
subtree:add(DISCO_DERP_PUB, buffer(offset, 32))
|
|
end
|
|
offset = offset + 32
|
|
|
|
-- Parse source port
|
|
subtree:add(DISCO_SRC_PORT, buffer:range(offset, 2):le_uint())
|
|
offset = offset + 2
|
|
|
|
-- Parse source address
|
|
local addr_len = buffer:range(offset, 2):le_uint()
|
|
offset = offset + 2
|
|
if addr_len == 4 then subtree:add(DISCO_SRC_IP_4, buffer:range(offset, addr_len))
|
|
else subtree:add(DISCO_SRC_IP_6, buffer:range(offset, addr_len))
|
|
end
|
|
offset = offset + addr_len
|
|
|
|
-- Handover to the actual disco frame dissector
|
|
offset = offset + 2 -- skip over payload len
|
|
local data_buffer = buffer:range(offset, packet_length-offset):tvb()
|
|
Dissector.get("disco"):call(data_buffer, pinfo, tree)
|
|
end
|
|
|
|
ts_dissectors:add(1, tsdisco_meta)
|
|
|
|
--
|
|
-- DISCO frame dissector
|
|
--
|
|
tsdisco_frame = Proto("disco", "Tailscale DISCO frame")
|
|
DISCO_TYPE = ProtoField.string("disco.TYPE", "Message type", base.ASCII)
|
|
DISCO_VERSION = ProtoField.uint8("disco.VERSION","Protocol version", base.DEC)
|
|
DISCO_TXID = ProtoField.bytes("disco.TXID", "Transaction ID", base.SPACE)
|
|
DISCO_NODEKEY = ProtoField.bytes("disco.NODE_KEY", "Node key", base.SPACE)
|
|
DISCO_PONG_SRC = ProtoField.ipv6("disco.PONG_SRC", "Pong source")
|
|
DISCO_PONG_SRC_PORT = ProtoField.uint16("disco.PONG_SRC_PORT","Source port", base.DEC)
|
|
DISCO_UNKNOWN = ProtoField.bytes("disco.UNKNOWN_DATA", "Trailing data", base.SPACE)
|
|
tsdisco_frame.fields = {DISCO_TYPE, DISCO_VERSION, DISCO_TXID, DISCO_NODEKEY, DISCO_PONG_SRC, DISCO_PONG_SRC_PORT, DISCO_UNKNOWN}
|
|
|
|
function tsdisco_frame.dissector(buffer, pinfo, tree)
|
|
packet_length = buffer:len()
|
|
local offset = 0
|
|
local subtree = tree:add(tsdisco_frame, buffer(), "DISCO frame")
|
|
|
|
-- Message type
|
|
local message_type = buffer(offset, 1):le_uint()
|
|
offset = offset + 1
|
|
if message_type == 1 then subtree:add(DISCO_TYPE, "Ping")
|
|
elseif message_type == 2 then subtree:add(DISCO_TYPE, "Pong")
|
|
elseif message_type == 3 then subtree:add(DISCO_TYPE, "Call me maybe")
|
|
end
|
|
|
|
-- Message version
|
|
local message_version = buffer(offset, 1):le_uint()
|
|
offset = offset + 1
|
|
subtree:add(DISCO_VERSION, message_version)
|
|
|
|
-- TXID (Ping / Pong)
|
|
if message_type == 1 or message_type == 2 then
|
|
subtree:add(DISCO_TXID, buffer(offset, 12))
|
|
offset = offset + 12
|
|
end
|
|
|
|
-- NodeKey (Ping)
|
|
if message_type == 1 then
|
|
subtree:add(DISCO_NODEKEY, buffer(offset, 32))
|
|
offset = offset + 32
|
|
end
|
|
|
|
-- Src (Pong)
|
|
if message_type == 2 then
|
|
subtree:add(DISCO_PONG_SRC, buffer:range(offset, 16))
|
|
offset = offset + 16
|
|
end
|
|
-- Src port (Pong)
|
|
if message_type == 2 then
|
|
subtree:add(DISCO_PONG_SRC_PORT, buffer(offset, 2):le_uint())
|
|
offset = offset + 2
|
|
end
|
|
|
|
-- TODO(tom): Parse CallMeMaybe.MyNumber
|
|
|
|
local trailing = buffer:range(offset, packet_length-offset)
|
|
if trailing:len() > 0 then
|
|
subtree:add(DISCO_UNKNOWN, trailing)
|
|
end
|
|
end
|
|
|
|
ts_dissectors:add(2, tsdisco_frame) |