jssip
Version:
the Javascript SIP library
319 lines (289 loc) • 7.75 kB
JavaScript
const Logger = require('./Logger');
const Grammar = require('./Grammar');
const SIPMessage = require('./SIPMessage');
const logger = new Logger('Parser');
/**
* Parse SIP Message
*/
exports.parseMessage = (data, ua) =>
{
let message;
let bodyStart;
let headerEnd = data.indexOf('\r\n');
if (headerEnd === -1)
{
logger.warn('parseMessage() | no CRLF found, not a SIP message');
return;
}
// Parse first line. Check if it is a Request or a Reply.
const firstLine = data.substring(0, headerEnd);
let parsed = Grammar.parse(firstLine, 'Request_Response');
if (parsed === -1)
{
logger.warn(`parseMessage() | error parsing first line of SIP message: "${firstLine}"`);
return;
}
else if (!parsed.status_code)
{
message = new SIPMessage.IncomingRequest(ua);
message.method = parsed.method;
message.ruri = parsed.uri;
}
else
{
message = new SIPMessage.IncomingResponse();
message.status_code = parsed.status_code;
message.reason_phrase = parsed.reason_phrase;
}
message.data = data;
let headerStart = headerEnd + 2;
/* Loop over every line in data. Detect the end of each header and parse
* it or simply add to the headers collection.
*/
while (true)
{
headerEnd = getHeader(data, headerStart);
// The SIP message has normally finished.
if (headerEnd === -2)
{
bodyStart = headerStart + 2;
break;
}
// Data.indexOf returned -1 due to a malformed message.
else if (headerEnd === -1)
{
logger.warn('parseMessage() | malformed message');
return;
}
parsed = parseHeader(message, data, headerStart, headerEnd);
if (parsed !== true)
{
logger.warn('parseMessage() |', parsed.error);
return;
}
headerStart = headerEnd + 2;
}
/* RFC3261 18.3.
* If there are additional bytes in the transport packet
* beyond the end of the body, they MUST be discarded.
*/
if (message.hasHeader('content-length'))
{
const contentLength = message.getHeader('content-length');
message.body = data.substr(bodyStart, contentLength);
}
else
{
message.body = data.substring(bodyStart);
}
return message;
};
/**
* Extract and parse every header of a SIP message.
*/
function getHeader(data, headerStart)
{
// 'start' position of the header.
let start = headerStart;
// 'end' position of the header.
let end = 0;
// 'partial end' position of the header.
let partialEnd = 0;
// End of message.
if (data.substring(start, start + 2).match(/(^\r\n)/))
{
return -2;
}
while (end === 0)
{
// Partial End of Header.
partialEnd = data.indexOf('\r\n', start);
// 'indexOf' returns -1 if the value to be found never occurs.
if (partialEnd === -1)
{
return partialEnd;
}
if (!data.substring(partialEnd + 2, partialEnd + 4).match(/(^\r\n)/) && data.charAt(partialEnd + 2).match(/(^\s+)/))
{
// Not the end of the message. Continue from the next position.
start = partialEnd + 2;
}
else
{
end = partialEnd;
}
}
return end;
}
function parseHeader(message, data, headerStart, headerEnd)
{
let parsed;
const hcolonIndex = data.indexOf(':', headerStart);
const headerName = data.substring(headerStart, hcolonIndex).trim();
const headerValue = data.substring(hcolonIndex + 1, headerEnd).trim();
// If header-field is well-known, parse it.
switch (headerName.toLowerCase())
{
case 'via':
case 'v':
message.addHeader('via', headerValue);
if (message.getHeaders('via').length === 1)
{
parsed = message.parseHeader('Via');
if (parsed)
{
message.via = parsed;
message.via_branch = parsed.branch;
}
}
else
{
parsed = 0;
}
break;
case 'from':
case 'f':
message.setHeader('from', headerValue);
parsed = message.parseHeader('from');
if (parsed)
{
message.from = parsed;
message.from_tag = parsed.getParam('tag');
}
break;
case 'to':
case 't':
message.setHeader('to', headerValue);
parsed = message.parseHeader('to');
if (parsed)
{
message.to = parsed;
message.to_tag = parsed.getParam('tag');
}
break;
case 'record-route':
parsed = Grammar.parse(headerValue, 'Record_Route');
if (parsed === -1)
{
parsed = undefined;
}
else
{
for (const header of parsed)
{
message.addHeader('record-route', headerValue.substring(header.possition, header.offset));
message.headers['Record-Route'][message.getHeaders('record-route').length - 1].parsed = header.parsed;
}
}
break;
case 'call-id':
case 'i':
message.setHeader('call-id', headerValue);
parsed = message.parseHeader('call-id');
if (parsed)
{
message.call_id = headerValue;
}
break;
case 'contact':
case 'm':
parsed = Grammar.parse(headerValue, 'Contact');
if (parsed === -1)
{
parsed = undefined;
}
else
{
for (const header of parsed)
{
message.addHeader('contact', headerValue.substring(header.possition, header.offset));
message.headers.Contact[message.getHeaders('contact').length - 1].parsed = header.parsed;
}
}
break;
case 'content-length':
case 'l':
message.setHeader('content-length', headerValue);
parsed = message.parseHeader('content-length');
break;
case 'content-type':
case 'c':
message.setHeader('content-type', headerValue);
parsed = message.parseHeader('content-type');
break;
case 'cseq':
message.setHeader('cseq', headerValue);
parsed = message.parseHeader('cseq');
if (parsed)
{
message.cseq = parsed.value;
}
if (message instanceof SIPMessage.IncomingResponse)
{
message.method = parsed.method;
}
break;
case 'max-forwards':
message.setHeader('max-forwards', headerValue);
parsed = message.parseHeader('max-forwards');
break;
case 'www-authenticate':
message.setHeader('www-authenticate', headerValue);
parsed = message.parseHeader('www-authenticate');
break;
case 'proxy-authenticate':
message.setHeader('proxy-authenticate', headerValue);
parsed = message.parseHeader('proxy-authenticate');
break;
case 'session-expires':
case 'x':
message.setHeader('session-expires', headerValue);
parsed = message.parseHeader('session-expires');
if (parsed)
{
message.session_expires = parsed.expires;
message.session_expires_refresher = parsed.refresher;
}
break;
case 'refer-to':
case 'r':
message.setHeader('refer-to', headerValue);
parsed = message.parseHeader('refer-to');
if (parsed)
{
message.refer_to = parsed;
}
break;
case 'replaces':
message.setHeader('replaces', headerValue);
parsed = message.parseHeader('replaces');
if (parsed)
{
message.replaces = parsed;
}
break;
case 'event':
case 'o':
message.setHeader('event', headerValue);
parsed = message.parseHeader('event');
if (parsed)
{
message.event = parsed;
}
break;
default:
// Do not parse this header.
message.addHeader(headerName, headerValue);
parsed = 0;
}
if (parsed === undefined)
{
return {
error : `error parsing header "${headerName}"`
};
}
else
{
return true;
}
}