data/method/mavlink/pymavlink/generator/mavgen_javascript.py

1243 lines
46 KiB
Python

#!/usr/bin/env python
'''
parse a MAVLink protocol XML file and generate a Node.js javascript module implementation
Based on original work Copyright Andrew Tridgell 2011
Released under GNU GPL version 3 or later
'''
from __future__ import print_function
from builtins import range
import os
import textwrap
from . import mavtemplate
import sys
t = mavtemplate.MAVTemplate()
def get_mavhead(xml):
return ("mavlink20" if xml.protocol_marker == 253 else "mavlink10")
def get_mavprocessor(xml):
return ("MAVLink20Processor" if xml.protocol_marker == 253 else "MAVLink10Processor")
def generate_preamble(outf, msgs, args, xml):
print("Generating preamble")
t.write(outf, """
/*
MAVLink protocol implementation for node.js (auto-generated by mavgen_javascript.py)
Generated from: ${FILELIST}
Note: this file has been auto-generated. DO NOT EDIT
*/
jspack = require("jspack").jspack,
_ = require("underscore"),
events = require("events"), // for .emit(..), MAVLink20Processor inherits from events.EventEmitter
util = require("util");
var Buffer = require('buffer').Buffer; // required in react - no impact in node
var Long = require('long');
// Add a convenience method to Buffer
Buffer.prototype.toByteArray = function () {
return Array.prototype.slice.call(this, 0)
}
${MAVHEAD} = function(){};
// Implement the CRC-16/MCRF4XX function (present in the Python version through the mavutil.py package)
${MAVHEAD}.x25Crc = function(buffer, crcIN) {
var bytes = buffer;
var crcOUT = crcIN === undefined ? 0xffff : crcIN;
_.each(bytes, function(e) {
var tmp = e ^ (crcOUT & 0xff);
tmp = (tmp ^ (tmp << 4)) & 0xff;
crcOUT = (crcOUT >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4);
crcOUT = crcOUT & 0xffff;
});
return crcOUT;
}
${MAVHEAD}.WIRE_PROTOCOL_VERSION = "${WIRE_PROTOCOL_VERSION}";
${MAVHEAD}.PROTOCOL_MARKER_V1 = 0xFE
${MAVHEAD}.PROTOCOL_MARKER_V2 = 0xFD
${MAVHEAD}.HEADER_LEN_V1 = 6
${MAVHEAD}.HEADER_LEN_V2 = 10
${MAVHEAD}.HEADER_LEN = ${HEADERLEN};
${MAVHEAD}.MAVLINK_TYPE_CHAR = 0
${MAVHEAD}.MAVLINK_TYPE_UINT8_T = 1
${MAVHEAD}.MAVLINK_TYPE_INT8_T = 2
${MAVHEAD}.MAVLINK_TYPE_UINT16_T = 3
${MAVHEAD}.MAVLINK_TYPE_INT16_T = 4
${MAVHEAD}.MAVLINK_TYPE_UINT32_T = 5
${MAVHEAD}.MAVLINK_TYPE_INT32_T = 6
${MAVHEAD}.MAVLINK_TYPE_UINT64_T = 7
${MAVHEAD}.MAVLINK_TYPE_INT64_T = 8
${MAVHEAD}.MAVLINK_TYPE_FLOAT = 9
${MAVHEAD}.MAVLINK_TYPE_DOUBLE = 10
${MAVHEAD}.MAVLINK_IFLAG_SIGNED = 0x01
${MAVHEAD}.MAVLINK_SIGNATURE_BLOCK_LEN = 13
// Mavlink headers incorporate sequence, source system (platform) and source component.
${MAVHEAD}.header = function(msgId, mlen, seq, srcSystem, srcComponent, incompat_flags=0, compat_flags=0,) {
this.mlen = ( typeof mlen === 'undefined' ) ? 0 : mlen;
this.seq = ( typeof seq === 'undefined' ) ? 0 : seq;
this.srcSystem = ( typeof srcSystem === 'undefined' ) ? 0 : srcSystem;
this.srcComponent = ( typeof srcComponent === 'undefined' ) ? 0 : srcComponent;
this.msgId = msgId
this.incompat_flags = incompat_flags
this.compat_flags = compat_flags
}
""", {'FILELIST' : ",".join(args),
'PROTOCOL_MARKER' : xml.protocol_marker,
'crc_extra' : xml.crc_extra,
'WIRE_PROTOCOL_VERSION' : ("2.0" if xml.protocol_marker == 253 else "1.0"),
'MAVHEAD': get_mavhead(xml),
'HEADERLEN': ("10" if xml.protocol_marker == 253 else "6")})
# Mavlink2
if (xml.protocol_marker == 253):
t.write(outf, """
${MAVHEAD}.header.prototype.pack = function() {
return jspack.Pack('BBBBBBBHB', [${PROTOCOL_MARKER}, this.mlen, this.incompat_flags, this.compat_flags, this.seq, this.srcSystem, this.srcComponent, ((this.msgId & 0xFF) << 8) | ((this.msgId >> 8) & 0xFF), this.msgId>>16]);
}
""", {'PROTOCOL_MARKER' : xml.protocol_marker,
'MAVHEAD': get_mavhead(xml)})
# Mavlink1
else:
t.write(outf, """
${MAVHEAD}.header.prototype.pack = function() {
return jspack.Pack('BBBBBB', [${PROTOCOL_MARKER}, this.mlen, this.seq, this.srcSystem, this.srcComponent, this.msgId]);
}
""", {'PROTOCOL_MARKER' : xml.protocol_marker,
'MAVHEAD': get_mavhead(xml)})
t.write(outf, """
// Base class declaration: mavlink.message will be the parent class for each
// concrete implementation in mavlink.messages.
${MAVHEAD}.message = function() {};
// Convenience setter to facilitate turning the unpacked array of data into member properties
${MAVHEAD}.message.prototype.set = function(args,verbose) {
// inspect
_.each(this.fieldnames, function(e, i) {
var num = parseInt(i,10);
if (this.hasOwnProperty(e) && isNaN(num) ){ // asking for an attribute that's non-numeric is ok unless its already an attribute we have
if ( verbose >= 1) { console.log("WARNING, overwriting an existing property is DANGEROUS:"+e+" ==>"+i+"==>"+args[i]+" -> "+JSON.stringify(this)); }
}
}, this);
//console.log(this.fieldnames);
// then modify
_.each(this.fieldnames, function(e, i) {
this[e] = args[i];
}, this);
};
// trying to be the same-ish as the python function of the same name
${MAVHEAD}.message.prototype.sign_packet = function( mav) {
var crypto= require('crypto');
var h = crypto.createHash('sha256');
//mav.signing.timestamp is a 48bit number, or 6 bytes.
// due to js not being able to shift numbers more than 32, we'll use this instead..
// js stores all its numbers as a 64bit float with 53 bits of mantissa, so have room for 48 ok.
// positive shifts left, negative shifts right
function shift(number, shift) {
return number * Math.pow(2, shift);
}
var thigh = shift(mav.signing.timestamp,-32) // 2 bytes from the top, shifted right by 32 bits
var tlow = (mav.signing.timestamp & 0xfffffff ) // 4 bytes from the bottom
// I means unsigned 4bytes, H means unsigned 2 bytes
// first add the linkid(1 byte) and timestamp(6 bytes) that start the signature
this._msgbuf = this._msgbuf.concat(jspack.Pack('<BIH', [mav.signing.link_id, tlow, thigh ] ) );
h.update(mav.signing.secret_key); // secret is already a Buffer
h.update(new Buffer.from(this._msgbuf));
var hashDigest = h.digest();
sig = hashDigest.slice(0,6)
this._msgbuf = this._msgbuf.concat( ... sig );
mav.signing.timestamp += 1
}
// This pack function builds the header and produces a complete MAVLink message,
// including header and message CRC.
${MAVHEAD}.message.prototype.pack = function(mav, crc_extra, payload) {
this._payload = payload;
var plen = this._payload.length;
""", {'MAVHEAD': get_mavhead(xml)})
# Mavlink2 only
if (xml.protocol_marker == 253):
t.write(outf, """
//in MAVLink2 we can strip trailing zeros off payloads. This allows for simple
// variable length arrays and smaller packets
while ((plen > 1) && ( (this._payload[plen-1] == 0) || (this._payload[plen-1] == null) ) ) {
plen = plen - 1;
}
this._payload = this._payload.slice(0, plen);
""")
t.write(outf, """
// signing is our first incompat flag.
var incompat_flags = 0;
if (mav.signing.sign_outgoing){
incompat_flags |= ${MAVHEAD}.MAVLINK_IFLAG_SIGNED
}
// header
this._header = new ${MAVHEAD}.header(this._id, this._payload.length, mav.seq, mav.srcSystem, mav.srcComponent, incompat_flags, 0,);
// payload
this._msgbuf = this._header.pack().concat(this._payload);
// crc - for now, assume always using crc_extra = True. TODO: check/fix this.
var crc = ${MAVHEAD}.x25Crc(this._msgbuf.slice(1));
crc = ${MAVHEAD}.x25Crc([crc_extra], crc);
this._msgbuf = this._msgbuf.concat(jspack.Pack('<H', [crc] ) );
// signing
this._signed = false
this._link_id = undefined
//console.log(mav.signing);
//optionally add signing
if (mav.signing.sign_outgoing){
this.sign_packet(mav)
}
return this._msgbuf;
}
""", {'MAVHEAD': get_mavhead(xml)})
def generate_enums(outf, enums, xml):
print("Generating enums")
outf.write("\n// enums\n")
wrapper = textwrap.TextWrapper(initial_indent="", subsequent_indent=" // ")
for e in enums:
outf.write("\n// %s\n" % e.name)
for entry in e.entry:
t.write(outf, "${MAVHEAD}.${ENUMNAME} = ${ENUMVAL} // ${ENUMDESC}\n", {'ENUMNAME': entry.name,
'ENUMVAL': entry.value,
'ENUMDESC': wrapper.fill(entry.description),
'MAVHEAD': get_mavhead(xml)})
def generate_message_ids(outf, msgs, xml):
print("Generating message IDs")
outf.write("\n// message IDs\n")
t.write(outf, "${MAVHEAD}.MAVLINK_MSG_ID_BAD_DATA = -1\n", {'MAVHEAD': get_mavhead(xml)})
for m in msgs:
t.write(outf, "${MAVHEAD}.MAVLINK_MSG_ID_${MNAME} = ${MVAL}\n", {'MAVHEAD': get_mavhead(xml),
'MNAME': m.name.upper(),
'MVAL': m.id})
def generate_classes(outf, msgs, xml):
"""
Generate the implementations of the classes representing MAVLink messages.
"""
print("Generating class definitions")
wrapper = textwrap.TextWrapper(initial_indent="", subsequent_indent="")
t.write(outf, "\n${MAVHEAD}.messages = {};\n\n", {'MAVHEAD': get_mavhead(xml)})
def field_descriptions(fields):
ret = ""
for f in fields:
if not f.omit_arg:
ret += " %-18s : %s (%s)\n" % (f.name, f.description.strip(), f.type)
return ret
# now do all the messages
for m in msgs:
# assemble some strings we'll use later in outputting ..
comment = "%s\n\n%s" % (wrapper.fill(m.description.strip()), field_descriptions(m.fields))
argfieldnames = []
conststr = ""
for f in m.fields:
if not f.omit_arg:
argfieldnames.append(f.name)
else:
conststr = conststr + " this.%s = %s;\n" % (f.name, f.const_value)
# instance field support copied from mavgen_python
if m.instance_field is not None:
instance_field = "'%s'" % m.instance_field
instance_offset = m.field_offsets[m.instance_field]
else:
instance_field = "undefined"
instance_offset = -1
# start with the comment block
outf.write("""
/*
%s
*/
""" % (comment))
# function signature + declaration
outf.write(" %s.messages.%s = function(" % ( get_mavhead(xml), m.name.lower() ) )
outf.write(" ...moreargs ) {\n")
# passing the dynamic args into the correct attributes, we can call the constructor with or without the 'moreargs'
outf.write(" [ this.%s ] = moreargs;\n" % " , this.".join(argfieldnames))
outf.write(conststr)
# body: set message type properties
outf.write("""
this._format = '%s';
this._id = %s.MAVLINK_MSG_ID_%s;
this.order_map = %s;
this.len_map = %s;
this.array_len_map = %s;
this.crc_extra = %u;
this._name = '%s';
this._instance_field = %s;
this._instance_offset = %d;
""" % (
m.fmtstr,
get_mavhead(xml),
m.name.upper(),
m.order_map,
m.len_map,
m.array_len_map,
m.crc_extra,
m.name.upper(),
instance_field,
instance_offset
))
# body: set own properties
if len(m.fieldnames) != 0:
outf.write(" this.fieldnames = ['%s'];\n" % "', '".join(m.fieldnames))
outf.write("\n}\n")
# inherit methods from the base message class
outf.write("\n%s.messages.%s.prototype = new %s.message;\n" % ( get_mavhead(xml), m.name.lower() ,get_mavhead(xml) ) )
orderedfields = "var orderedfields = [ this." + ", this.".join(m.ordered_fieldnames) + "];";
# Implement the pack() function for this message
t.write(outf, """
${MAVHEAD}.messages.${MNAME}.prototype.pack = function(mav) {
${MORDERED}
var j = jspack.Pack(this._format, orderedfields);
if (j === false ) throw new Error("jspack unable to handle this packet");
return ${MAVHEAD}.message.prototype.pack.call(this, mav, this.crc_extra, j );\n}\n\n""", {'MORDERED': orderedfields, 'MAVHEAD': get_mavhead(xml), 'MNAME': m.name.lower()})
def mavfmt(field):
'''work out the struct format for a type'''
map = {
'float' : 'f',
'double' : 'd',
'char' : 'c',
'int8_t' : 'b',
'uint8_t' : 'B',
'uint8_t_mavlink_version' : 'B',
'int16_t' : 'h',
'uint16_t' : 'H',
'int32_t' : 'i',
'uint32_t' : 'I',
'int64_t' : 'q',
'uint64_t' : 'Q',
}
if field.array_length:
if field.type in ['char', 'int8_t', 'uint8_t']:
return str(field.array_length)+'s'
return str(field.array_length)+map[field.type]
return map[field.type]
def generate_mavlink_class(outf, msgs, xml):
print("Generating MAVLink class")
# Write mapper to enable decoding based on the integer message type
t.write(outf, "\n\n${MAVHEAD}.map = {\n", {'MAVHEAD': get_mavhead(xml)});
for m in msgs:
outf.write(" %s: { format: '%s', type: %s.messages.%s, order_map: %s, crc_extra: %u },\n" % (
m.id, m.fmtstr, get_mavhead(xml), m.name.lower(), m.order_map, m.crc_extra))
outf.write("}\n\n")
t.write(outf, """
// Special mavlink message to capture malformed data packets for debugging
${MAVHEAD}.messages.bad_data = function(data, reason) {
this._id = ${MAVHEAD}.MAVLINK_MSG_ID_BAD_DATA;
this._data = data;
this._reason = reason;
this._msgbuf = data;
}
${MAVHEAD}.messages.bad_data.prototype = new ${MAVHEAD}.message;
// MAVLink signing state class
MAVLinkSigning = function MAVLinkSigning(object){
this.secret_key = new Buffer.from([]) ; //new Buffer.from([ 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 ]) // secret key must be a Buffer obj of 32 length
this.timestamp = 1
this.link_id = 0
this.sign_outgoing = false // todo false this
this.allow_unsigned_callback = undefined
this.stream_timestamps = {}
this.sig_count = 0
this.badsig_count = 0
this.goodsig_count = 0
this.unsigned_count = 0
this.reject_count = 0
}
/* MAVLink protocol handling class */
${MAVPROCESSOR} = function(logger, srcSystem, srcComponent) {
this.logger = logger;
this.seq = 0;
this.buf = new Buffer.from([]);
this.bufInError = new Buffer.from([]);
this.srcSystem = (typeof srcSystem === 'undefined') ? 0 : srcSystem;
this.srcComponent = (typeof srcComponent === 'undefined') ? 0 : srcComponent;
this.have_prefix_error = false;
// The first packet we expect is a valid header, 6 bytes.
this.protocol_marker = ${PROTOCOL_MARKER};
this.expected_length = ${MAVHEAD}.HEADER_LEN;
this.little_endian = true;
this.crc_extra = true;
this.sort_fields = true;
this.total_packets_sent = 0;
this.total_bytes_sent = 0;
this.total_packets_received = 0;
this.total_bytes_received = 0;
this.total_receive_errors = 0;
this.startup_time = Date.now();
// optional , but when used we store signing state in this object:
this.signing = new MAVLinkSigning();
}
// Implements EventEmitter
util.inherits(${MAVPROCESSOR}, events.EventEmitter);
// If the logger exists, this function will add a message to it.
// Assumes the logger is a winston object.
${MAVPROCESSOR}.prototype.log = function(message) {
if(this.logger) {
this.logger.info(message);
}
}
${MAVPROCESSOR}.prototype.log = function(level, message) {
if(this.logger) {
this.logger.log(level, message);
}
}
${MAVPROCESSOR}.prototype.send = function(mavmsg) {
buf = mavmsg.pack(this);
this.file.write(buf);
this.seq = (this.seq + 1) % 256;
this.total_packets_sent +=1;
this.total_bytes_sent += buf.length;
}
// return number of bytes needed for next parsing stage
${MAVPROCESSOR}.prototype.bytes_needed = function() {
ret = this.expected_length - this.buf.length;
return ( ret <= 0 ) ? 1 : ret;
}
// add data to the local buffer
${MAVPROCESSOR}.prototype.pushBuffer = function(data) {
if(data) {
this.buf = Buffer.concat([this.buf, data]); // python calls this self.buf.extend(c)
this.total_bytes_received += data.length;
}
}
// Decode prefix. Elides the prefix.
${MAVPROCESSOR}.prototype.parsePrefix = function() {
// Test for a message prefix.
if( this.buf.length >= 1 && this.buf[0] != this.protocol_marker ) {
// Strip the offending initial byte and throw an error.
var badPrefix = this.buf[0];
this.bufInError = this.buf.slice(0,1);
this.buf = this.buf.slice(1);
this.expected_length = ${MAVHEAD}.HEADER_LEN; //initially we 'expect' at least the length of the header, later parseLength corrects for this.
throw new Error("Bad prefix ("+badPrefix+")");
}
}
// Determine the length. Leaves buffer untouched.
// Although the 'len' of a packet is available as of the second byte, the third byte with 'incompat_flags' lets
// us know if we have signing enabled, which affects the real-world length by the signature-block length of 13 bytes.
// once successful, 'this.expected_length' is correctly set for the whole packet.
${MAVPROCESSOR}.prototype.parseLength = function() {
if( this.buf.length >= 3 ) {
var unpacked = jspack.Unpack('BBB', this.buf.slice(0, 3));
var magic = unpacked[0]; // stx ie fd or fe etc
this.expected_length = unpacked[1] + ${MAVHEAD}.HEADER_LEN + 2 // length of message + header + CRC (ie non-signed length)
this.incompat_flags = unpacked[2];
// mavlink2 only.. in mavlink1, incompat_flags var above is actually the 'seq', but for this test its ok.
if ((magic == ${MAVHEAD}.PROTOCOL_MARKER_V2 ) && ( this.incompat_flags & ${MAVHEAD}.MAVLINK_IFLAG_SIGNED )){
this.expected_length += ${MAVHEAD}.MAVLINK_SIGNATURE_BLOCK_LEN;
}
}
}
// input some data bytes, possibly returning a new message - python equiv function is called parse_char / __parse_char_legacy
${MAVPROCESSOR}.prototype.parseChar = function(c) {
var m = null;
try {
this.pushBuffer(c);
this.parsePrefix();
this.parseLength();
m = this.parsePayload();
} catch(e) {
this.log('error', e.message);
this.total_receive_errors += 1;
m = new ${MAVHEAD}.messages.bad_data(this.bufInError, e.message);
this.bufInError = new Buffer.from([]);
}
// emit a packet-specific message as well as a generic message, user/s can choose to use either or both of these.
if(null != m) {
this.emit(m._name, m);
this.emit('message', m);
}
return m;
}
// continuation of python's __parse_char_legacy
${MAVPROCESSOR}.prototype.parsePayload = function() {
var m = null;
// tip: this.expected_length and this.incompat_flags both already set correctly by parseLength(..) above
// If we have enough bytes to try and read it, read it.
// shortest packet is header+checksum(2) with no payload, so we need at least that many
// but once we have a longer 'expected length' we have to read all of it.
if(( this.expected_length >= ${MAVHEAD}.HEADER_LEN+2) && (this.buf.length >= this.expected_length) ) {
// Slice off the expected packet length, reset expectation to be to find a header.
var mbuf = this.buf.slice(0, this.expected_length);
// TODO: slicing off the buffer should depend on the error produced by the decode() function
// - if we find a well formed message, cut-off the expected_length
// - if the message is not well formed (correct prefix by accident), cut-off 1 char only
this.buf = this.buf.slice(this.expected_length);
this.expected_length = ${MAVHEAD}.HEADER_LEN; // after attempting a parse, we'll next expect to find just a header.
try {
m = this.decode(mbuf);
this.total_packets_received += 1;
}
catch(e) {
// Set buffer in question and re-throw to generic error handling
this.bufInError = mbuf;
throw e;
}
}
return m;
}
// input some data bytes, possibly returning an array of new messages
${MAVPROCESSOR}.prototype.parseBuffer = function(s) {
// Get a message, if one is available in the stream.
var m = this.parseChar(s);
// No messages available, bail.
if ( null === m ) {
return null;
}
// While more valid messages can be read from the existing buffer, add
// them to the array of new messages and return them.
var ret = [m];
while(true) {
m = this.parseChar();
if ( null === m ) {
// No more messages left.
return ret;
}
ret.push(m);
}
}
// from Buffer to ArrayBuffer
function toArrayBuffer(buf) {
var ab = new ArrayBuffer(buf.length);
var view = new Uint8Array(ab);
for (var i = 0; i < buf.length; ++i) {
view[i] = buf[i];
}
return ab;
}
// and back
function toBuffer(ab) {
var buf = Buffer.alloc(ab.byteLength);
var view = new Uint8Array(ab);
for (var i = 0; i < buf.length; ++i) {
buf[i] = view[i];
}
return buf;
}
//check signature on incoming message , many of the comments in this file come from the python impl
${MAVPROCESSOR}.prototype.check_signature = function(msgbuf, srcSystem, srcComponent) {
//if (isinstance(msgbuf, array.array)){
// msgbuf = msgbuf.tostring()
//}
if ( Buffer.isBuffer(msgbuf) ) {
msgbuf = toArrayBuffer(msgbuf);
}
//timestamp_buf = msgbuf[-12:-6]
var timestamp_buf= msgbuf.slice(-12,-6);
//link_id = msgbuf[-13]
var link_id= new Buffer.from(msgbuf.slice(-13,-12)); // just a single byte really, but returned as a buffer
link_id = link_id[0]; // get the first byte.
//self.mav_sign_unpacker = jspack.Unpack('<IH')
// (tlow, thigh) = self.mav_sign_unpacker.unpack(timestamp_buf)
// I means unsigned 4bytes, H means unsigned 2 bytes
var t = jspack.Unpack('<IH',new Buffer.from(timestamp_buf))
const [tlow, thigh] = t;
// due to js not being able to shift numbers more than 32, we'll use this instead..
// js stores all its numbers as a 64bit float with 53 bits of mantissa, so have room for 48 ok.
function shift(number, shift) {
return number * Math.pow(2, shift);
}
var thigh_shifted = shift(thigh,32);
var timestamp = tlow + thigh_shifted
// see if the timestamp is acceptable
// we'll use a STRING containing these three things in it as a unique key eg: '0,1,1'
stream_key = new Array(link_id,srcSystem,srcComponent).toString();
if (stream_key in this.signing.stream_timestamps){
if (timestamp <= this.signing.stream_timestamps[stream_key]){
//# reject old timestamp
//console.log('old timestamp')
return false
}
}else{
//# a new stream has appeared. Accept the timestamp if it is at most
//# one minute behind our current timestamp
if (timestamp + 6000*1000 < this.signing.timestamp){
//console.log('bad new stream ', timestamp/(100.0*1000*60*60*24*365), this.signing.timestamp/(100.0*1000*60*60*24*365))
return false
}
this.signing.stream_timestamps[stream_key] = timestamp;
//console.log('new stream',this.signing.stream_timestamps)
}
// h = hashlib.new('sha256')
// h.update(this.signing.secret_key)
// h.update(msgbuf[:-6])
var crypto= require('crypto');
var h = crypto.createHash('sha256');
// just the last 6 of 13 available are the actual sig . ie excluding the linkid(1) and timestamp(6)
var sigpart = msgbuf.slice(-6);
sigpart = new Buffer.from(sigpart);
// not sig part 0- end-minus-6
var notsigpart = msgbuf.slice(0,-6);
notsigpart = new Buffer.from(notsigpart);
h.update(this.signing.secret_key); // secret is already a Buffer
//var tmp = h.copy().digest();
h.update(notsigpart);
//var tmp2 = h.copy().digest()
var hashDigest = h.digest();
sig1 = hashDigest.slice(0,6)
//sig1 = str(h.digest())[:6]
//sig2 = str(msgbuf)[-6:]
// can't just compare sigs, need a full buffer compare like this...
//if (sig1 != sigpart){
if (Buffer.compare(sig1,sigpart)){
//console.log('sig mismatch',sig1,sigpart)
return false
}
//# the timestamp we next send with is the max of the received timestamp and
//# our current timestamp
this.signing.timestamp = Math.max(this.signing.timestamp, timestamp)
return true
}
/* decode a buffer as a MAVLink message */
${MAVPROCESSOR}.prototype.decode = function(msgbuf) {
var magic, incompat_flags, compat_flags, mlen, seq, srcSystem, srcComponent, unpacked, msgId, signature_len;
// decode the header
try {
""", {'MAVPROCESSOR': get_mavprocessor(xml),
'MAVHEAD': get_mavhead(xml),
'PROTOCOL_MARKER': xml.protocol_marker})
# Mavlink2 only
if (xml.protocol_marker == 253):
t.write(outf, """
unpacked = jspack.Unpack('cBBBBBBHB', msgbuf.slice(0, 10)); // the H in here causes msgIDlow to takeup 2 bytes, the rest 1
magic = unpacked[0];
mlen = unpacked[1];
incompat_flags = unpacked[2];
compat_flags = unpacked[3];
seq = unpacked[4];
srcSystem = unpacked[5];
srcComponent = unpacked[6];
var msgIDlow = ((unpacked[7] & 0xFF) << 8) | ((unpacked[7] >> 8) & 0xFF); // first-two msgid bytes
var msgIDhigh = unpacked[8]; // the 3rd msgid byte
msgId = msgIDlow | (msgIDhigh<<16); // combined result. 0 - 16777215 24bit number
""", {'MAVHEAD': get_mavhead(xml)})
# Mavlink1
else:
t.write(outf, """
unpacked = jspack.Unpack('cBBBBB', msgbuf.slice(0, 6));
magic = unpacked[0];
mlen = unpacked[1];
seq = unpacked[2];
srcSystem = unpacked[3];
srcComponent = unpacked[4];
msgId = unpacked[5];
""", {'MAVHEAD': get_mavhead(xml)})
t.write(outf, """
}
catch(e) {
throw new Error('Unable to unpack MAVLink header: ' + e.message);
}
// TODO allow full parsing of 1.0 inside the 2.0 parser, this is just a start
if (magic == ${MAVHEAD}.PROTOCOL_MARKER_V1){
//headerlen = 6;
// these two are in the same place in both v1 and v2 so no change needed:
//magic = magic;
//mlen = mlen;
// grab mavlink-v1 header position info from v2 unpacked position
seq1 = incompat_flags;
srcSystem1 = compat_flags;
srcComponent1 = seq;
msgId1 = srcSystem;
// override the v1 vs v2 offsets so we get the correct data either way...
seq = seq1;
srcSystem = srcSystem1;
srcComponent = srcComponent1;
msgId = msgId1;
// don't exist in mavlink1, so zero-them
incompat_flags = 0;
compat_flags = 0;
signature_len = 0;
// todo add more v1 here and don't just return
return;
}
if (magic.charCodeAt(0) != this.protocol_marker) {
throw new Error("Invalid MAVLink prefix ("+magic.charCodeAt(0)+")");
}
// is packet supposed to be signed?
if ( incompat_flags & ${MAVHEAD}.MAVLINK_IFLAG_SIGNED ){
signature_len = ${MAVHEAD}.MAVLINK_SIGNATURE_BLOCK_LEN;
} else {
signature_len = 0;
}
// header's declared len compared to packets actual len
var actual_len = (msgbuf.length - (${MAVHEAD}.HEADER_LEN + 2 + signature_len));
var actual_len_nosign = (msgbuf.length - (${MAVHEAD}.HEADER_LEN + 2 ));
if ((mlen == actual_len) && (signature_len > 0)){
var len_if_signed = mlen+signature_len;
//console.log("Packet appears signed && labeled as signed, OK. msgId=" + msgId);
} else if ((mlen == actual_len_nosign) && (signature_len > 0)){
var len_if_signed = mlen+signature_len;
throw new Error("Packet appears unsigned when labeled as signed. Got actual_len "+actual_len_nosign+" expected " + len_if_signed + ", msgId=" + msgId);
} else if( mlen != actual_len) {
throw new Error("Invalid MAVLink message length. Got " + (msgbuf.length - (${MAVHEAD}.HEADER_LEN + 2)) + " expected " + mlen + ", msgId=" + msgId);
}
if( false === _.has(${MAVHEAD}.map, msgId) ) {
throw new Error("Unknown MAVLink message ID (" + msgId + ")");
}
// here's the common chunks of packet we want to work with below..
var headerBuf= msgbuf.slice(${MAVHEAD}.HEADER_LEN); // first10
var sigBuf = msgbuf.slice(-signature_len); // last 13 or nothing
var crcBuf1 = msgbuf.slice(-2); // either last-2 or last-2-prior-to-signature
var crcBuf2 = msgbuf.slice(-15,-13); // either last-2 or last-2-prior-to-signature
var payloadBuf = msgbuf.slice(${MAVHEAD}.HEADER_LEN, -(signature_len+2)); // the remaining bit between the header and the crc
var crcCheckBuf = msgbuf.slice(1, -(signature_len+2)); // the part uses to calculate the crc - ie between the magic and signature,
// decode the payload
// refs: (fmt, type, order_map, crc_extra) = ${MAVHEAD}.map[msgId]
var decoder = ${MAVHEAD}.map[msgId];
// decode the checksum
var receivedChecksum = undefined;
if ( signature_len == 0 ) { // unsigned
try {
receivedChecksum = jspack.Unpack('<H', crcBuf1);
} catch (e) {
throw new Error("Unable to unpack MAVLink unsigned CRC: " + e.message);
}
} else { // signed
try {
receivedChecksum = jspack.Unpack('<H', crcBuf2);
} catch (e) {
throw new Error("Unable to unpack MAVLink signed CRC: " + e.message);
}
}
receivedChecksum = receivedChecksum[0];
// make our own chksum of the relevant part of the packet...
var messageChecksum = ${MAVHEAD}.x25Crc(crcCheckBuf);
var messageChecksum2 = ${MAVHEAD}.x25Crc([decoder.crc_extra], messageChecksum);
if ( receivedChecksum != messageChecksum2 ) {
throw new Error('invalid MAVLink CRC in msgID ' +msgId+ ', got ' + receivedChecksum + ' checksum, calculated payload checksum as '+messageChecksum2 );
}
// now check the signature...
var sig_ok = false
if (signature_len == ${MAVHEAD}.MAVLINK_SIGNATURE_BLOCK_LEN){
this.signing.sig_count += 1
}
// it's a Buffer, zero-length means unused
if (this.signing.secret_key.length != 0 ){
var accept_signature = false;
if (signature_len == ${MAVHEAD}.MAVLINK_SIGNATURE_BLOCK_LEN){
sig_ok = this.check_signature(msgbuf, srcSystem, srcComponent);
accept_signature = sig_ok;
if (sig_ok){
this.signing.goodsig_count += 1
}else{
this.signing.badsig_count += 1
}
if ( (! accept_signature) && (this.signing.allow_unsigned_callback != undefined) ){
accept_signature = this.signing.allow_unsigned_callback(this, msgId);
if (accept_signature){
this.signing.unsigned_count += 1
}else{
this.signing.reject_count += 1
}
}
}else if (this.signing.allow_unsigned_callback != undefined){
accept_signature = this.signing.allow_unsigned_callback(this, msgId);
if (accept_signature){
this.signing.unsigned_count += 1
}else{
this.signing.reject_count += 1
}
}
if (!accept_signature) throw new Error('Invalid signature');
}
// now look at the specifics of the payload...
var paylen = jspack.CalcLength(decoder.format);
""", {'MAVPROCESSOR': get_mavprocessor(xml),
'MAVHEAD': get_mavhead(xml)})
# Mavlink2 only
if (xml.protocol_marker == 253):
t.write(outf, """
//put any truncated 0's back in (ie zero-pad )
if (paylen > payloadBuf.length) {
payloadBuf = Buffer.concat([payloadBuf, Buffer.alloc(paylen - payloadBuf.length)]);
}
""")
t.write(outf, """
// Decode the payload and reorder the fields to match the order map.
try {
var t = jspack.Unpack(decoder.format, payloadBuf);
}
catch (e) {
throw new Error('Unable to unpack MAVLink payload type='+decoder.type+' format='+decoder.format+' payloadLength='+ payloadBuf +': '+ e.message);
}
// Need to check if the message contains arrays
var args = {};
const elementsInMsg = decoder.order_map.length;
const actualElementsInMsg = JSON.parse(JSON.stringify(t)).length;
if (elementsInMsg == actualElementsInMsg) {
// Reorder the fields to match the order map
_.each(t, function(e, i, l) {
args[i] = t[decoder.order_map[i]]
});
} else {
// This message contains arrays
var typeIndex = 1;
var orderIndex = 0;
var memberIndex = 0;
var tempArgs = {};
// Walk through the fields
for(var i = 0, size = decoder.format.length-1; i <= size; ++i) {
var order = decoder.order_map[orderIndex];
var currentType = decoder.format[typeIndex];
if (isNaN(parseInt(currentType))) {
// This field is not an array check the type and add it to the args
tempArgs[orderIndex] = t[memberIndex];
memberIndex++;
} else {
// This field is part of an array, need to find the length of the array
var arraySize = ''
var newArray = []
while (!isNaN(decoder.format[typeIndex])) {
arraySize = arraySize + decoder.format[typeIndex];
typeIndex++;
}
// Now that we know how long the array is, create an array with the values
for(var j = 0, size = parseInt(arraySize); j < size; ++j){
newArray.push(t[j+orderIndex]);
memberIndex++;
}
// Add the array to the args object
arraySize = arraySize + decoder.format[typeIndex];
currentType = arraySize;
tempArgs[orderIndex] = newArray;
}
orderIndex++;
typeIndex++;
}
// Finally reorder the fields to match the order map
_.each(t, function(e, i, l) {
args[i] = tempArgs[decoder.order_map[i]]
});
}
// construct the message object
try {
// args at this point might look like: { '0': 6, '1': 8, '2': 0, '3': 0, '4': 3, '5': 3 }
var m = new decoder.type(); // make a new 'empty' instance of the right class,
m.set(args,false); // associate ordered-field-numbers to names, after construction not during.
}
catch (e) {
throw new Error('Unable to instantiate MAVLink message of type '+decoder.type+' : ' + e.message);
}
m._signed = sig_ok;
if (m._signed) { m._link_id = msgbuf[-13]; }
m._msgbuf = msgbuf;
m._payload = payloadBuf
m.crc = receivedChecksum;
m._header = new ${MAVHEAD}.header(msgId, mlen, seq, srcSystem, srcComponent, incompat_flags, compat_flags);
this.log(m);
return m;
}
""", {'MAVHEAD': get_mavhead(xml), 'MAVPROCESSOR': get_mavprocessor(xml), 'PROTOCOL_MARKER' : xml.protocol_marker})
def generate_footer(outf, xml):
t.write(outf, """
// allow loading as both common.js (Node), and/or vanilla javascript in-browser
if(typeof module === "object" && module.exports) {
module.exports = {${MAVHEAD}, ${MAVPROCESSOR}};
}
""", {'MAVHEAD': get_mavhead(xml), 'MAVPROCESSOR': get_mavprocessor(xml)})
#--------------------------------------tests start--------
def isfloat(value):
try:
float(value)
return True
except ValueError:
return False
def generate_tests_preamble(outf, msgs, args, xml):
print("Generating preamble")
t.write(outf, """
/*
TESTS for MAVLink protocol implementation for node.js (auto-generated by mavgen_javascript.py)
Generated from: ${FILELIST}
Note: this file has been auto-generated. DO NOT EDIT
*/
var Long = require('long');
var {${MAVHEAD}, ${MAVPROCESSOR}} = require('./mavlink.js');
// mock mav with sysid-42 and componentid=150
let mav = new ${MAVPROCESSOR}(null, 42, 150);
// this uses the above mock by default, but lets us override it before or during tests if desired
let set_mav = function (_mav) {
// set global mav var from local
mav = _mav;
};
exports.set_mav = set_mav;
let verbose = 0; // 0 means not verbose, 1 means a bit more, 2 means most verbose
let set_verbose = function (_v) {
// set global mav var from local
verbose = _v;
};
exports.set_verbose = set_verbose;
// relevant to how we pass-in the Long object/s to jspack, we'll assume the calling user is smart enough to know that.
var wrap_long = function (someLong) {
return [someLong.getLowBitsUnsigned(), someLong.getHighBitsUnsigned()];
}
""", {'FILELIST' : ",".join(args),
'PROTOCOL_MARKER' : xml.protocol_marker,
'crc_extra' : xml.crc_extra,
'WIRE_PROTOCOL_VERSION' : ("2.0" if xml.protocol_marker == 253 else "1.0"),
'MAVHEAD': get_mavhead(xml),
'MAVPROCESSOR': get_mavprocessor(xml),
'HEADERLEN': ("10" if xml.protocol_marker == 253 else "6")}
)
def generate_tests_mavlink_class(outf, msgs, xml):
print("Generating MAVLink class")
# Write mapper to enable decoding based on the integer message type
#t.write(outf, "\n\n${MAVHEAD}.map = {\n", {'MAVHEAD': get_mavhead(xml)});
for m in msgs:
outf.write("let test_%s = function () {\n"% ( m.name.lower()));
#var bs = new mavlink20.messages.battery_status(
outf.write(" if ( verbose == 2 ) console.log('test creating and packing:%s'); \n" % ( m.name.lower() ) )
outf.write(" if ( verbose == 1) { process.stdout.write('test creating and packing:"+m.name.lower()+" \\r'); }\n")
outf.write(" var test_%s = new %s.messages.%s(); \n" % ( m.name.lower(),get_mavhead(xml), m.name.lower()))
idx = 0; # test data is in same order as ordered_fieldnames
for f in m.ordered_fieldnames:
tdata = m.test_data[idx] # test data
#tdatatype = m.test_data_types[idx] # type of test data
fieldtype = m.ordered_fieldtypes[idx] # type of base field
# wrap things non-number-like as strings, isnumeric() can't handle negatives, but conveniently none of the test suite uses negatives
#print('testdata:'+tdata);
#print('tdatatype:'+tdatatype);
#print('fieldtype:'+fieldtype);
#if tdatatype != fieldtype:
# sys.exit()
_isnum = str(tdata).isdigit()
_isarray = (tdata[0] == '[')
_isfloat = isfloat(tdata)
# javascript inconveniently considers bits >=128 in quite a lot of data types to be unicode, not binary, so we have to understand
# these and create them via Buffers and 'binary' or other whacky-doodle-ness here to be sure we get all the tests to pass.
# array of chars
if _isarray and (fieldtype == 'char'):
tdata = 'new Buffer.from('+m.test_data[idx]+').toString("binary")'; # binary encoding here is important for bits >= 128
# array of uint8_t ( like char )
elif _isarray and ( (fieldtype == 'uint8_t') or (fieldtype == 'int8_t') ):
tdata = 'new Buffer.from('+m.test_data[idx]+').toString("binary")'; # binary encoding here is important for bits >= 128
# float/uint16_t/int16_t/int8_t/double array is apparently simple enough without Buffer wrapper
elif _isarray and ( (fieldtype == 'float') or (fieldtype == 'uint16_t') or (fieldtype == 'int16_t') or (fieldtype == 'double') or ( fieldtype == 'int32_t' ) or ( fieldtype == 'uint32_t' ) ):
tdata = m.test_data[idx];
# array of other things
elif _isarray:
tdata = 'new Buffer.from('+m.test_data[idx]+') // generic buffer error?';
# https://github.com/birchroad/node-jspack/pull/4/commits/9828de064af42ab370009d3eeec7fc11be36b918
elif fieldtype == 'uint64_t': # unsigned
tdata = 'wrap_long(Long.fromString("'+m.test_data[idx]+'", true))'; # create unsigned Long from string, then rearrange Long object into 2x32bit unsigned ready for jspack
elif fieldtype == 'int64_t': # signed
tdata = 'wrap_long(Long.fromString("'+m.test_data[idx]+'", false))'; # same as above, but signed Long
# special signed handling, to properly
elif fieldtype == 'int8_t': # signed fields, we sometimes push raw value/s that exceed the min/max range of signed instead of using the correct sign
tdata = '(new Int8Array(['+m.test_data[idx]+']))[0]'; # basically a cast from unsigned int to signed int without sign bit loss
# special signed handling, to properly
elif fieldtype == 'int16_t': # signed fields, we sometimes push raw value/s that exceed the min/max range of signed instead of using the correct sign
tdata = '(new Int16Array(['+m.test_data[idx]+']))[0]'; # basically a cast from unsigned int to signed int without sign bit loss
# special signed handling, to properly
elif fieldtype == 'int32_t': # signed fields, we sometimes push raw value/s that exceed the min/max range of signed instead of using the correct sign
tdata = '(new Int32Array(['+m.test_data[idx]+']))[0]'; # basically a cast from unsigned int to signed int without sign bit loss
elif _isfloat:
tdata = m.test_data[idx];
elif _isnum:
tdata = m.test_data[idx];
else:
#string
tdata = '"'+m.test_data[idx]+'"';
outf.write( " test_%s.%s = %s;" % ( m.name.lower(),f, tdata) );
outf.write(" // fieldtype: %s "%(fieldtype));
outf.write(" isarray: %s \n"%(_isarray));
idx=idx+1;
outf.write(" //var t = new Buffer.from([])\n; //%s\n"% ( m.name.lower()));
outf.write(" var t = new Buffer.from(test_%s.pack(mav));\n"% ( m.name.lower()));
outf.write(" return [test_%s,t]; // return an array of unpacked and packed options\n"% ( m.name.lower()));
outf.write("};\n");
outf.write("exports.test_%s = test_%s; // expose in module\n"% ( m.name.lower() ,m.name.lower() ) );
outf.write("\n");
outf.write(get_mavhead(xml)+"""Tests = function(){ \n""")
for m in msgs:
outf.write("test_%s();\n"% ( m.name.lower()));
outf.write("};\n");
def generate_tests_footer(outf, xml):
t.write(outf, """
// if run as an app, run the tests immediately, but if run as a module don't, require user to call
if (require.main === module) {
verbose=2; // 0 is not verbose, 1 is a bit, 2 is more.
${MAVHEAD}Tests();
}
/* TESTs for MAVLink protocol handling class */
${MAVPROCESSOR}Tests = function() { ${MAVHEAD}Tests(); }
exports.${MAVPROCESSOR}Tests = ${MAVPROCESSOR}Tests; // expose in module
""", {'MAVHEAD': get_mavhead(xml), 'MAVPROCESSOR': get_mavprocessor(xml)})
def generate(basename, xml):
'''generate complete javascript implementation'''
if basename.endswith('.js'):
filename = basename
else:
filename = basename + '.js'
msgs = []
enums = []
filelist = []
for x in xml:
msgs.extend(x.message)
enums.extend(x.enum)
filelist.append(os.path.basename(x.filename))
for m in msgs:
m.fielddefaults = []
if xml[0].little_endian:
m.fmtstr = '<'
else:
m.fmtstr = '>'
m.native_fmtstr = m.fmtstr
# we've got instance support in generator, but not in the resultant code, yet.
m.instance_field = None
for f in m.ordered_fields:
m.fmtstr += mavfmt(f)
if f.instance:
m.instance_field = f.name
m.order_map = [0] * len(m.fieldnames)
m.len_map = [0] * len(m.fieldnames)
m.array_len_map = [0] * len(m.fieldnames)
m.test_data = [0] * len(m.fieldnames)
m.test_data_types = [0] * len(m.fieldnames)
for i in range(0, len(m.fieldnames)):
m.order_map[i] = m.ordered_fieldnames.index(m.fieldnames[i])
m.ordered_fieldtypes[i] = m.ordered_fieldtypes[i]
m.test_data[i] = str(m.ordered_fields[i].test_value)
m.test_data_types[i] = str(m.ordered_fields[i].type)
m.array_len_map[i] = m.ordered_fields[i].array_length
for i in range(0, len(m.fieldnames)):
n = m.order_map[i]
m.len_map[n] = m.fieldlengths[i]
print("Generating %s" % filename)
outf = open(filename, "w")
generate_preamble(outf, msgs, filelist, xml[0])
generate_enums(outf, enums, xml[0])
generate_message_ids(outf, msgs, xml[0])
generate_classes(outf, msgs, xml[0])
generate_mavlink_class(outf, msgs, xml[0])
generate_footer(outf, xml[0])
outf.close()
print("Generated %s OK" % filename)
testfilename = filename.replace('.js','.tests.js')
print("Generating TESTS %s" % testfilename)
outf = open(testfilename, "w")
generate_tests_preamble(outf, msgs, filelist, xml[0])
generate_tests_mavlink_class(outf, msgs, xml[0])
generate_tests_footer(outf, xml[0])
outf.close()
print("Generating TESTS %s" % testfilename)