Add a systemd unit for arch and a wireshark dissector (#216)

dist/arch/nebula.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=nebula
+Wants=basic.target
+After=basic.target network.target
+
+[Service]
+SyslogIdentifier=nebula
+StandardOutput=syslog
+StandardError=syslog
+ExecReload=/bin/kill -HUP $MAINPID
+ExecStart=/usr/bin/nebula -config /etc/nebula/config.yml
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

dist/wireshark/nebula.lua

@@ -0,0 +1,113 @@
+local nebula = Proto("nebula", "nebula")
+
+local default_settings = {
+    port      = 4242,
+    all_ports = false,
+}
+
+nebula.prefs.port  = Pref.uint("Port number", default_settings.port, "The UDP port number for Nebula")
+nebula.prefs.all_ports  = Pref.bool("All ports", default_settings.all_ports, "Assume nebula packets on any port, useful when dealing with hole punching")
+
+local pf_version  = ProtoField.new("version", "nebula.version", ftypes.UINT8, nil, base.DEC, 0xF0)
+local pf_type     = ProtoField.new("type", "nebula.type", ftypes.UINT8, {
+    [0] = "handshake",
+    [1] = "message",
+    [2] = "recvError",
+    [3] = "lightHouse",
+    [4] = "test",
+    [5] = "closeTunnel",
+}, base.DEC, 0x0F)
+
+local pf_subtype = ProtoField.new("subtype", "nebula.subtype", ftypes.UINT8, nil, base.DEC)
+local pf_subtype_test = ProtoField.new("subtype", "nebula.subtype", ftypes.UINT8, {
+    [0] = "request",
+    [1] = "reply",
+}, base.DEC)
+
+local pf_subtype_handshake = ProtoField.new("subtype", "nebula.subtype", ftypes.UINT8, {
+    [0] = "ix_psk0",
+}, base.DEC)
+
+local pf_reserved        = ProtoField.new("reserved",     "nebula.reserved",     ftypes.UINT16, nil, base.HEX)
+local pf_remote_index    = ProtoField.new("remote index", "nebula.remote_index", ftypes.UINT32, nil, base.DEC)
+local pf_message_counter = ProtoField.new("counter",      "nebula.counter",      ftypes.UINT64, nil, base.DEC)
+local pf_payload         = ProtoField.new("payload",      "nebula.payload",      ftypes.BYTES,  nil, base.NONE)
+
+nebula.fields = { pf_version, pf_type, pf_subtype, pf_subtype_handshake, pf_subtype_test, pf_reserved, pf_remote_index, pf_message_counter, pf_payload }
+
+local ef_holepunch = ProtoExpert.new("nebula.holepunch.expert", "Nebula hole punch packet", expert.group.PROTOCOL, expert.severity.NOTE)
+local ef_punchy = ProtoExpert.new("nebula.punchy.expert", "Nebula punchy keepalive packet", expert.group.PROTOCOL, expert.severity.NOTE)
+
+nebula.experts = { ef_holepunch, ef_punchy }
+local type_field = Field.new("nebula.type")
+local subtype_field = Field.new("nebula.subtype")
+
+function nebula.dissector(tvbuf, pktinfo, root)
+    -- set the protocol column to show our protocol name
+    pktinfo.cols.protocol:set("NEBULA")
+
+    local pktlen = tvbuf:reported_length_remaining()
+    local tree = root:add(nebula, tvbuf:range(0,pktlen))
+
+    if pktlen == 0 then
+        tree:add_proto_expert_info(ef_holepunch)
+        pktinfo.cols.info:append(" (holepunch)")
+        return
+    elseif pktlen == 1 then
+        tree:add_proto_expert_info(ef_punchy)
+        pktinfo.cols.info:append(" (punchy)")
+        return
+    end
+
+    tree:add(pf_version, tvbuf:range(0,1))
+    local type = tree:add(pf_type,    tvbuf:range(0,1))
+
+    local nebula_type = bit32.band(tvbuf:range(0,1):uint(), 0x0F)
+    if nebula_type == 0 then
+        local stage = tvbuf(8,8):uint64()
+        tree:add(pf_subtype_handshake, tvbuf:range(1,1))
+        type:append_text(" stage " .. stage)
+        pktinfo.cols.info:append(" (" .. type_field().display .. ", stage " .. stage .. ", " .. subtype_field().display .. ")")
+    elseif nebula_type == 4 then
+        tree:add(pf_subtype_test, tvbuf:range(1,1))
+        pktinfo.cols.info:append(" (" .. type_field().display .. ", " .. subtype_field().display .. ")")
+    else
+        tree:add(pf_subtype, tvbuf:range(1,1))
+        pktinfo.cols.info:append(" (" .. type_field().display .. ")")
+    end
+
+    tree:add(pf_reserved,        tvbuf:range(2,2))
+    tree:add(pf_remote_index,    tvbuf:range(4,4))
+    tree:add(pf_message_counter, tvbuf:range(8,8))
+    tree:add(pf_payload,         tvbuf:range(16,tvbuf:len() - 16))
+end
+
+function nebula.prefs_changed()
+    if default_settings.all_ports == nebula.prefs.all_ports and default_settings.port == nebula.prefs.port then
+        -- Nothing changed, bail
+        return
+    end
+
+    -- Remove our old dissector
+    DissectorTable.get("udp.port"):remove_all(nebula)
+
+    if nebula.prefs.all_ports and default_settings.all_ports ~= nebula.prefs.all_ports then
+        default_settings.all_port = nebula.prefs.all_ports
+
+        for i=0, 65535 do
+            DissectorTable.get("udp.port"):add(i, nebula)
+        end
+
+        -- no need to establish again on specific ports
+        return
+    end
+
+
+    if default_settings.all_ports ~= nebula.prefs.all_ports then
+        -- Add our new port dissector
+        default_settings.port = nebula.prefs.port
+        DissectorTable.get("udp.port"):add(default_settings.port, nebula)
+    end
+end
+
+DissectorTable.get("udp.port"):add(default_settings.port, nebula)