public DtlsSrtpClient(Certificate certificateChain, AsymmetricKeyParameter privateKey,
UseSrtpData clientSrtpData)
{
if (certificateChain == null && privateKey == null)
{
(certificateChain, privateKey) = DtlsUtils.CreateSelfSignedTlsCert();
}
if (clientSrtpData == null)
{
SecureRandom random = new SecureRandom();
int[] protectionProfiles = { SrtpProtectionProfile.SRTP_AES128_CM_HMAC_SHA1_80 };
byte[] mki = new byte[(SrtpParameters.SRTP_AES128_CM_HMAC_SHA1_80.GetCipherKeyLength() +
SrtpParameters.SRTP_AES128_CM_HMAC_SHA1_80.GetCipherSaltLength()) / 8];
random.NextBytes(mki); // Reusing our secure random for generating the key.
this.clientSrtpData = new UseSrtpData(protectionProfiles, mki);
}
else
{
this.clientSrtpData = clientSrtpData;
}
this.mPrivateKey = privateKey;
mCertificateChain = certificateChain;
//Generate FingerPrint
var certificate = mCertificateChain.GetCertificateAt(0);
Fingerprint = certificate != null?DtlsUtils.Fingerprint(certificate) : null;
}
public DtlsSrtpServer(Certificate certificateChain, AsymmetricKeyParameter privateKey)
{
this.cipherSuites = base.GetCipherSuites();
this.mPrivateKey = privateKey;
mCertificateChain = certificateChain;
//Generate FingerPrint
var certificate = mCertificateChain.GetCertificateAt(0);
this.mFingerPrint = certificate != null?DtlsUtils.Fingerprint(certificate) : null;
}
public DtlsSrtpServer(Certificate certificateChain, AsymmetricKeyParameter privateKey)
{
if (certificateChain == null && privateKey == null)
{
(certificateChain, privateKey) = DtlsUtils.CreateSelfSignedTlsCert();
}
this.cipherSuites = base.GetCipherSuites();
this.mPrivateKey = privateKey;
mCertificateChain = certificateChain;
//Generate FingerPrint
var certificate = mCertificateChain.GetCertificateAt(0);
this.mFingerPrint = certificate != null?DtlsUtils.Fingerprint(certificate) : null;
}
/// <summary>
/// Attempts to parse the fingerprint fields from a string.
/// </summary>
/// <param name="str">The string to parse from.</param>
/// <param name="fingerprint">If successful a fingerprint object.</param>
/// <returns>True if a fingerprint was successfully parsed. False if not.</returns>
public static bool TryParse(string str, out RTCDtlsFingerprint fingerprint)
{
fingerprint = null;
if (string.IsNullOrEmpty(str))
{
return(false);
}
else
{
int spaceIndex = str.IndexOf(' ');
if (spaceIndex == -1)
{
return(false);
}
else
{
string algStr = str.Substring(0, spaceIndex);
string val = str.Substring(spaceIndex + 1);
if (!DtlsUtils.IsHashSupported(algStr))
{
return(false);
}
else
{
fingerprint = new RTCDtlsFingerprint
{
algorithm = algStr,
value = val
};
return(true);
}
}
}
}
/// <summary>
/// Updates the session after receiving the remote SDP.
/// At this point check that the codecs match. We currently only support:
/// - Audio: PCMU,
/// - Video: VP8.
/// If they are not available there's no point carrying on.
/// </summary>
/// <param name="sessionDescription">The answer/offer SDP from the remote party.</param>
public SetDescriptionResultEnum setRemoteDescription(RTCSessionDescriptionInit init)
{
RTCSessionDescription description = new RTCSessionDescription {
type = init.type, sdp = SDP.ParseSDPDescription(init.sdp)
};
remoteDescription = description;
SDP remoteSdp = SDP.ParseSDPDescription(init.sdp);
SdpType sdpType = (init.type == RTCSdpType.offer) ? SdpType.offer : SdpType.answer;
var setResult = base.SetRemoteDescription(sdpType, remoteSdp);
if (setResult == SetDescriptionResultEnum.OK)
{
string remoteIceUser = remoteSdp.IceUfrag;
string remoteIcePassword = remoteSdp.IcePwd;
string dtlsFingerprint = remoteSdp.DtlsFingerprint;
var audioAnnounce = remoteSdp.Media.Where(x => x.Media == SDPMediaTypesEnum.audio).FirstOrDefault();
if (audioAnnounce != null)
{
remoteIceUser = remoteIceUser ?? audioAnnounce.IceUfrag;
remoteIcePassword = remoteIcePassword ?? audioAnnounce.IcePwd;
dtlsFingerprint = dtlsFingerprint ?? audioAnnounce.DtlsFingerprint;
}
var videoAnnounce = remoteSdp.Media.Where(x => x.Media == SDPMediaTypesEnum.video).FirstOrDefault();
if (videoAnnounce != null)
{
if (remoteIceUser == null || remoteIcePassword == null || dtlsFingerprint == null)
{
remoteIceUser = remoteIceUser ?? videoAnnounce.IceUfrag;
remoteIcePassword = remoteIcePassword ?? videoAnnounce.IcePwd;
dtlsFingerprint = dtlsFingerprint ?? videoAnnounce.DtlsFingerprint;
}
}
SdpSessionID = remoteSdp.SessionId;
if (init.type == RTCSdpType.answer)
{
_rtpIceChannel.IsController = true;
// Set DTLS role to be server.
IceRole = IceRolesEnum.passive;
}
else
{
// Set DTLS role as client.
IceRole = IceRolesEnum.active;
}
if (remoteIceUser != null && remoteIcePassword != null)
{
_rtpIceChannel.SetRemoteCredentials(remoteIceUser, remoteIcePassword);
}
if (!string.IsNullOrWhiteSpace(dtlsFingerprint))
{
dtlsFingerprint = dtlsFingerprint.Trim().ToLower();
if (RTCDtlsFingerprint.TryParse(dtlsFingerprint, out var remoteFingerprint))
{
RemotePeerDtlsFingerprint = remoteFingerprint;
}
else
{
logger.LogWarning($"The DTLS fingerprint was invalid or not supported.");
return(SetDescriptionResultEnum.DtlsFingerprintDigestNotSupported);
}
}
else
{
logger.LogWarning("The DTLS fingerprint was missing from the remote party's session description.");
return(SetDescriptionResultEnum.DtlsFingerprintMissing);
}
// All browsers seem to have gone to trickling ICE candidates now but just
// in case one or more are given we can start the STUN dance immediately.
if (remoteSdp.IceCandidates != null)
{
foreach (var iceCandidate in remoteSdp.IceCandidates)
{
addIceCandidate(new RTCIceCandidateInit {
candidate = iceCandidate
});
}
}
foreach (var media in remoteSdp.Media)
{
if (media.IceCandidates != null)
{
foreach (var iceCandidate in media.IceCandidates)
{
addIceCandidate(new RTCIceCandidateInit {
candidate = iceCandidate
});
}
}
}
signalingState = RTCSignalingState.have_remote_offer;
onsignalingstatechange?.Invoke();
}
return(setResult);
}