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fix handling of late offer scenarios #20

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fix handling of late offer scenarios #20

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cac13c5
fix handling of late offer scenarios
rhondahollis Sep 7, 2022
2e0e4a9
handle to-tag change on Sequential Ring
rhondahollis Nov 3, 2022
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208 changes: 119 additions & 89 deletions lib/call-session.js
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Original file line number Diff line number Diff line change
Expand Up @@ -75,13 +75,14 @@ class CallSession extends Emitter {
this.subscribeDTMF = subscribeDTMF;
this.unsubscribeDTMF = unsubscribeDTMF;

const { callDirection, remoteUri, callid } = this.req.locals;
const { callDirection, remoteUri, callid, is3pcc } = this.req.locals;
const parsedUri = parseUri(uri);
const trunk = parsedUri.host;
let inviteSent;

//outbound is a call from webrtc (public) toward the SBC (private).
const rtpDirection = 'outbound' === callDirection ? ['public', 'private'] : ['private', 'public'];
const direction3pcc = 'outbound' === callDirection ? ['private', 'public'] : ['public', 'private'];
this.rtpEngineOpts = makeRtpEngineOpts(this.req, ('outbound' === callDirection), ('inbound' === callDirection));
this.rtpEngineResource = { destroy: this.del.bind(null, this.rtpEngineOpts.common) };
const opts = {
Expand All @@ -93,17 +94,19 @@ class CallSession extends Emitter {
};

try {
const response = await this.offer(opts);
this.logger.debug({ opts, response }, 'response from rtpengine to offer');
if ('ok' !== response.result) {
this.logger.error({}, `rtpengine offer failed with ${JSON.stringify(response)}`);
throw new Error(`failed allocating endpoint for callID ${callid} from rtpengine: ${JSON.stringify(response)}`);
}
let offerResponse;
if (!is3pcc) {
offerResponse = await this.offer(opts);
this.logger.debug({ opts, offerResponse }, 'response from rtpengine to offer');
if ('ok' !== offerResponse.result) {
this.logger.error({}, `rtpengine offer failed with ${JSON.stringify(offerResponse)}`);
throw new Error(`failed allocating endpoint for callID ${callid} from rtpengine: ${JSON.stringify(offerResponse)}`);
}

if ('outbound' === callDirection && response.sdp) {
response.sdp = removeWebrtcAttributes(response.sdp);
if ('outbound' === callDirection) {
offerResponse.sdp = removeWebrtcAttributes(offerResponse.sdp);
}
}

const headers = createHeaders(this.registrar, callid);

// check to see if we are sending to a trunk that we hold sip credentials for
Expand All @@ -116,7 +119,6 @@ class CallSession extends Emitter {
const callOpts = {
headers,
...(t && { auth: t.auth }),
localSdpB: response.sdp,
proxyRequestHeaders: [
'from',
'to',
Expand All @@ -140,22 +142,52 @@ class CallSession extends Emitter {
this.logger.info({ callOpts }, 'sending INVITE to B');
const { uas, uac } = await this.srf.createB2BUA(this.req, this.res, remoteUri, {
...callOpts,
noAck: is3pcc,
localSdpA: async (sdp, res) => {
this.rtpEngineOpts.uac.tag = res.getParsedHeader('To').params.tag;
//if the To tag changes on the final response (as in a Sequential Ring scenario), the rtpengine does not support this scenario,
// and the rtcp-mux attribute ends up missing from the sdp on the final response. Forcing the To-tag to remain the same for the rtpengine
// is the workaround.
if (null == this.rtpEngineOpts.uac.tag) {
this.rtpEngineOpts.uac.tag = res.getParsedHeader('To').params.tag;
}
const opts = {
...this.rtpEngineOpts.common,
...this.rtpEngineOpts.uas.mediaOpts,
'from-tag': this.rtpEngineOpts.uas.tag,
'to-tag': this.rtpEngineOpts.uac.tag,
sdp
};
const response = await this.answer(opts);
const opts3pcc = {
...this.rtpEngineOpts.common,
...this.rtpEngineOpts.uas.mediaOpts,
'from-tag': this.rtpEngineOpts.uac.tag,
'to-tag': this.rtpEngineOpts.uas.tag,
'direction': direction3pcc,
sdp
}
const response = is3pcc ? await this.offer(opts3pcc) : await this.answer(opts)
if ('ok' !== response.result) {
this.logger.error(`rtpengine answer failed with ${JSON.stringify(response)}`);
throw new Error('rtpengine failed: answer');
}
return response.sdp;
}
},
localSdpB: is3pcc ? async (sdp) => {
this.logger.info('sending ACK to B');
opts.sdp = sdp;
Object.assign(opts, {
'to-tag': this.rtpEngineOpts.uas.tag,
'from-tag': this.rtpEngineOpts.uac.tag
});
const response = await this.answer(opts);
this.logger.debug({ opts, response }, 'response from rtpengine to offer with sdp from ACK');
if ('ok' !== response.result) {
this.logger.error({}, `rtpengine (re)offer failed with ${JSON.stringify(response)}`);
throw new Error(
`failed allocating endpoint for callID ${callid} from rtpengine: ${JSON.stringify(response)}`);
}
return response.sdp;
} : offerResponse.sdp
}, {
cbRequest: (err, req) => inviteSent = req
});
Expand Down Expand Up @@ -234,65 +266,80 @@ class CallSession extends Emitter {
async _handleReinvite(dlg, req, res) {
try {
this.logger.info(`received reinvite on ${dlg.type} leg`);
const fromTag = dlg.type === 'uas' ? this.rtpEngineOpts.uas.tag : this.rtpEngineOpts.uac.tag;
const toTag = dlg.type === 'uas' ? this.rtpEngineOpts.uac.tag : this.rtpEngineOpts.uas.tag;
const offerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uac.mediaOpts : this.rtpEngineOpts.uas.mediaOpts;
const answerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uas.mediaOpts : this.rtpEngineOpts.uac.mediaOpts;
let opts = {
...this.rtpEngineOpts.common,
...offerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp: req.body,
};

let response = await this.offer(opts);
if ('ok' !== response.result) {
res.send(488);
throw new Error(`_onReinvite: rtpengine failed: offer: ${JSON.stringify(response)}`);
}
this.logger.debug({ opts, response }, 'sent offer for reinvite to rtpengine');
if (JSON.stringify(offerMedia).includes('ICE\":\"remove')) {
response.sdp = removeWebrtcAttributes(response.sdp);
}

let ackFunc;
let optsSdp;
if (!req.body) {
const fromTag = dlg.type === 'uas' ? this.rtpEngineOpts.uac.tag : this.rtpEngineOpts.uas.tag;
const toTag = dlg.type === 'uas' ? this.rtpEngineOpts.uas.tag : this.rtpEngineOpts.uac.tag;
const offerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uas.mediaOpts : this.rtpEngineOpts.uac.mediaOpts;

//reINVITE has no sdp. Send the INVITE on without passing it to rtengine first.
const modifyOpts = makeModifyDialogOpts(req, true);
this.logger.info({ modifyOpts }, 'calling dlg.modify with opts');
const { sdp, ack } = await dlg.other.modify(response.sdp, modifyOpts);
const { sdp, ack } = await dlg.other.modify(req.sdp, modifyOpts);
this.logger.info({ sdp }, 'return from dlg.modify with sdp');
optsSdp = sdp;
ackFunc = ack
}
else {
const modifyOpts = makeModifyDialogOpts(req, false);
optsSdp = await dlg.other.modify(response.sdp, modifyOpts);
}

opts = {
...this.rtpEngineOpts.common,
...answerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp: optsSdp
};
response = await this.answer(opts);
if ('ok' !== response.result) {
res.send(488);
throw new Error(`_onReinvite: rtpengine failed: ${JSON.stringify(response)}`);
let opts = {
...this.rtpEngineOpts.common,
...offerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp
};
//Pass the sdp from the response to rtpengine as an Offer
const response = await this.offer(opts);
if ('ok' !== response.result) {
res.send(488);
throw new Error(`_onReinvite: rtpengine failed: offer: ${JSON.stringify(response)}`);
}
res.send(200, { body: response.sdp });
// set listener for ACK, so that we can use that SDP to create the ACK for the other leg.
dlg.once('ack', this._handleAck.bind(this, dlg, ack, sdp));
}
else {
const fromTag = dlg.type === 'uas' ? this.rtpEngineOpts.uas.tag : this.rtpEngineOpts.uac.tag;
const toTag = dlg.type === 'uas' ? this.rtpEngineOpts.uac.tag : this.rtpEngineOpts.uas.tag;
const offerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uac.mediaOpts : this.rtpEngineOpts.uas.mediaOpts;
const answerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uas.mediaOpts : this.rtpEngineOpts.uac.mediaOpts;

//reINVITE has sdp
let opts = {
...this.rtpEngineOpts.common,
...offerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp: req.body,
};
let response = await this.offer(opts);
if ('ok' !== response.result) {
res.send(488);
throw new Error(`_onReinvite: rtpengine failed: offer: ${JSON.stringify(response)}`);
}
this.logger.debug({ opts, response }, 'sent offer for reinvite to rtpengine');
if (JSON.stringify(offerMedia).includes('ICE\":\"remove')) {
response.sdp = removeWebrtcAttributes(response.sdp);
}

if (JSON.stringify(answerMedia).includes('ICE\":\"remove')) {
response.sdp = removeWebrtcAttributes(response.sdp);
}
res.send(200, { body: response.sdp });
const modifyOpts = makeModifyDialogOpts(req, false);
const optsSdp = await dlg.other.modify(response.sdp, modifyOpts);

opts = {
...this.rtpEngineOpts.common,
...answerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp: optsSdp
};
response = await this.answer(opts);
if ('ok' !== response.result) {
res.send(488);
throw new Error(`_onReinvite: rtpengine failed: ${JSON.stringify(response)}`);
}

if (ackFunc) {
// set listener for ACK, so that we can use that SDP to create the ACK for the other leg.
dlg.once('ack', this._handleAck.bind(this, dlg, ackFunc, optsSdp));
}
if (JSON.stringify(answerMedia).includes('ICE\":\"remove')) {
response.sdp = removeWebrtcAttributes(response.sdp);
}
res.send(200, { body: response.sdp });
}
} catch (err) {
this.logger.error({ err }, 'Error handling reinvite');
}
Expand Down Expand Up @@ -368,34 +415,17 @@ class CallSession extends Emitter {
this.logger.info('Received ACK with late offer: ', offerSdp);

try {
let fromTag = dlg.other.sip.remoteTag;
let toTag = dlg.other.sip.localTag;
if (dlg.type === 'uac') {
fromTag = dlg.sip.localTag;
toTag = dlg.sip.remoteTag;
}
const offerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uas.mediaOpts : this.rtpEngineOpts.uac.mediaOpts;
const fromTag = dlg.type === 'uas' ? this.rtpEngineOpts.uac.tag : this.rtpEngineOpts.uas.tag;
const toTag = dlg.type === 'uas' ? this.rtpEngineOpts.uas.tag : this.rtpEngineOpts.uac.tag;
let answerMedia = dlg.type === 'uas' ? this.rtpEngineOpts.uac.mediaOpts : this.rtpEngineOpts.uas.mediaOpts;
const mediaStringified = JSON.stringify(answerMedia);
//if uas is webrtc facing, we need to keep that side as the active ssl role, so use passive in the ACK sdp
if (dlg.type === 'uas' && JSON.stringify(answerMedia).includes('SAVPF')) {
let mediaStringified = JSON.stringify(answerMedia);
mediaStringified = mediaStringified.replace('SAVPF\"', 'SAVPF\",\"DTLS\":\"passive\"');
answerMedia = JSON.parse(mediaStringified);
}

const optsOffer = {
...this.rtpEngineOpts.common,
...offerMedia,
'from-tag': fromTag,
'to-tag': toTag,
sdp: offerSdp
};
//send an offer first so that rtpEngine knows that DTLS fingerprint needs to be in the answer sdp.
const response = await this.offer(optsOffer);
if ('ok' !== response.result) {
throw new Error(`_handleAck: rtpengine failed: offer: ${JSON.stringify(response)}`);
if (!this.req.locals.is3pcc && dlg.type === 'uas' && mediaStringified.includes('SAVPF')) {
const updatedMedia = mediaStringified.replace('SAVPF\"', 'SAVPF\",\"DTLS\":\"passive\"');
answerMedia = JSON.parse(updatedMedia);
}

//Offer was already sent in _handleReInvite
const optsAnswer = {
...this.rtpEngineOpts.common,
...answerMedia,
Expand All @@ -407,7 +437,7 @@ class CallSession extends Emitter {
if ('ok' !== ackResponse.result) {
throw new Error(`_handleAck ${req.get('Call-Id')}: rtpengine failed: answer: ${JSON.stringify(ackResponse)}`);
}
if (JSON.stringify(answerMedia).includes('ICE\":\"remove')) {
if (mediaStringified.includes('ICE\":\"remove')) {
ackResponse.sdp = removeWebrtcAttributes(ackResponse.sdp);
}
//send the ACK with sdp
Expand Down
4 changes: 4 additions & 0 deletions lib/middleware.js
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,10 @@ module.exports = function(srf, logger) {
const callid = req.get('Call-Id');
const from = req.getParsedHeader('From');
req.locals = {logger: logger.child({callid}), from, callid};
if (!req.body) {
req.locals.logger.info('incoming INVITE has no SDP');
req.locals.is3pcc = true;
}
next();
};

Expand Down
4 changes: 2 additions & 2 deletions package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -28,11 +28,11 @@
},
"homepage": "https://github.com/voxbone/drachtio-rtpengine-webrtcproxy#readme",
"dependencies": {
"@jambonz/rtpengine-utils": "^0.3.1",
"@jambonz/rtpengine-utils": "^0.3.2",
"config": "^3.3.7",
"drachtio-fn-b2b-sugar": "0.0.12",
"drachtio-mw-registration-parser": "0.0.2",
"drachtio-srf": "^4.5.13",
"drachtio-srf": "^4.5.17",
"pino": "^4.17.6",
"rtpengine-client": "^0.2.0",
"uuid": "^3.4.0"
Expand Down