public static bool TryParse(string cryptoLine, out SDPSecurityDescription securityDescription)
{
securityDescription = null;
if (string.IsNullOrWhiteSpace(cryptoLine))
{
return(false);
}
if (!cryptoLine.StartsWith(CRYPTO_ATTRIBUE_PREFIX))
{
throw new FormatException($"cryptoLine '{cryptoLine}' is not recognized as a valid SDP Security Description ");
}
string sCryptoValue = cryptoLine.Substring(cryptoLine.IndexOf(COLON) + 1);
securityDescription = new SDPSecurityDescription();
string[] sCryptoParts = sCryptoValue.Split(securityDescription.WHITE_SPACES, StringSplitOptions.RemoveEmptyEntries);
if (sCryptoValue.Length < 2)
{
throw new FormatException($"cryptoLine '{cryptoLine}' is not recognized as a valid SDP Security Description ");
}
try
{
securityDescription.Tag = uint.Parse(sCryptoParts[0]);
securityDescription.CryptoSuite = (from e in Enum.GetNames(typeof(CryptoSuites)) where e.CompareTo(sCryptoParts[1]) == 0 select(CryptoSuites) Enum.Parse(typeof(CryptoSuites), e)).FirstOrDefault();
if (securityDescription.CryptoSuite == CryptoSuites.unknown)
{
//this may not be a reason to return FALSE
//there might be a new crypto key used
}
string[] sKeyParams = sCryptoParts[2].Split(SEMI_COLON);
if (sKeyParams.Length < 1)
{
securityDescription = null;
return(false);
}
foreach (string kp in sKeyParams)
{
KeyParameter keyParam = KeyParameter.Parse(kp, securityDescription.CryptoSuite);
securityDescription.KeyParams.Add(keyParam);
}
if (sCryptoParts.Length > 3)
{
securityDescription.SessionParam = SessionParameter.Parse(sCryptoParts[3], securityDescription.CryptoSuite);
}
return(true);
}
catch
{
//catch all errors and throw own FormatException
}
return(false);
}
public static SessionParameter Parse(string sessionParam,
CryptoSuites cryptoSuite = CryptoSuites.AES_CM_128_HMAC_SHA1_80)
{
if (string.IsNullOrWhiteSpace(sessionParam))
{
return(null);
}
string p = sessionParam.Trim();
try
{
SessionParameter.SrtpSessionParams paramType = SrtpSessionParams.unknown;
if (p.StartsWith(KDR_PREFIX))
{
string sKdr = p.Substring(KDR_PREFIX.Length);
uint kdr = 0;
if (uint.TryParse(sKdr, out kdr))
{
return(new SessionParameter(SrtpSessionParams.kdr)
{
Kdr = kdr
});
}
}
else if (p.StartsWith(WSH_PREFIX))
{
string sWsh = p.Substring(WSH_PREFIX.Length);
uint wsh = 0;
if (uint.TryParse(sWsh, out wsh))
{
return(new SessionParameter(SrtpSessionParams.wsh)
{
Wsh = wsh
});
}
}
else if (p.StartsWith(FEC_KEY_PREFIX))
{
string sFecKey = p.Substring(FEC_KEY_PREFIX.Length);
KeyParameter fecKey = KeyParameter.Parse(sFecKey, cryptoSuite);
return(new SessionParameter(SrtpSessionParams.fec_key)
{
FecKey = fecKey
});
}
else if (p.StartsWith(FEC_ORDER_PREFIX))
{
string sFecOrder = p.Substring(FEC_ORDER_PREFIX.Length);
SessionParameter.FecTypes fecOrder =
(from e in Enum.GetNames(typeof(FecTypes))
where e.CompareTo(sFecOrder) == 0
select(FecTypes) Enum.Parse(typeof(FecTypes), e)).FirstOrDefault();
if (fecOrder == FecTypes.unknown)
{
throw new FormatException(
$"sessionParam '{sessionParam}' is not recognized as a valid SRTP_SESSION_PARAM ");
}
return(new SessionParameter(SrtpSessionParams.fec_order)
{
FecOrder = fecOrder
});
}
else
{
paramType = (from e in Enum.GetNames(typeof(SrtpSessionParams))
where e.CompareTo(p) == 0
select(SrtpSessionParams) Enum.Parse(typeof(SrtpSessionParams), e)).FirstOrDefault();
if (paramType == SrtpSessionParams.unknown)
{
throw new FormatException(
$"sessionParam '{sessionParam}' is not recognized as a valid SRTP_SESSION_PARAM ");
}
switch (paramType)
{
case SrtpSessionParams.UNAUTHENTICATED_SRTP:
case SrtpSessionParams.UNENCRYPTED_SRTCP:
case SrtpSessionParams.UNENCRYPTED_SRTP:
return(new SessionParameter(paramType));
}
}
}
catch
{
//catch all errors and throw own FormatException
}
throw new FormatException(
$"sessionParam '{sessionParam}' is not recognized as a valid SRTP_SESSION_PARAM ");
}