/// <summary>
/// New transaction ACK requests are for 2xx responses, i.e. INVITE accepted and dialogue being created.
/// </summary>
/// <remarks>
/// From RFC 3261 Chapter 17.1.1.3 - ACK for non-2xx final responses
///
/// IMPORTANT:
/// an ACK for a non-2xx response will also have the same branch ID as the INVITE whose response it acknowledges.
///
/// The ACK request constructed by the client transaction MUST contain
/// values for the Call-ID, From, and Request-URI that are equal to the
/// values of those header fields in the request passed to the transport
/// by the client transaction (call this the "original request"). The To
/// header field in the ACK MUST equal the To header field in the
/// response being acknowledged, and therefore will usually differ from
/// the To header field in the original request by the addition of the
/// tag parameter. The ACK MUST contain a single Via header field, and
/// this MUST be equal to the top Via header field of the original
/// request. The CSeq header field in the ACK MUST contain the same
/// value for the sequence number as was present in the original request,
/// but the method parameter MUST be equal to "ACK".
///
/// If the INVITE request whose response is being acknowledged had Route
/// header fields, those header fields MUST appear in the ACK. This is
/// to ensure that the ACK can be routed properly through any downstream
/// stateless proxies.
///
/// From RFC 3261 Chapter 13.2.2.4 - ACK for 2xx final responses
///
/// IMPORTANT:
/// an ACK for a 2xx final response is a new transaction and has a new branch ID.
///
/// The UAC core MUST generate an ACK request for each 2xx received from
/// the transaction layer. The header fields of the ACK are constructed
/// in the same way as for any request sent within a dialog (see Section
/// 12) with the exception of the CSeq and the header fields related to
/// authentication. The sequence number of the CSeq header field MUST be
/// the same as the INVITE being acknowledged, but the CSeq method MUST
/// be ACK. The ACK MUST contain the same credentials as the INVITE. If
/// the 2xx contains an offer (based on the rules above), the ACK MUST
/// carry an answer in its body. If the offer in the 2xx response is not
/// acceptable, the UAC core MUST generate a valid answer in the ACK and
/// then send a BYE immediately.
/// </remarks>
private SIPRequest GetNewTransactionACKRequest(SIPResponse sipResponse, SIPURI ackURI, SIPEndPoint localSIPEndPoint)
{
SIPRequest ackRequest = new SIPRequest(SIPMethodsEnum.ACK, ackURI.ToString());
ackRequest.LocalSIPEndPoint = localSIPEndPoint;
SIPHeader header = new SIPHeader(TransactionRequest.Header.From, sipResponse.Header.To, sipResponse.Header.CSeq, sipResponse.Header.CallId);
header.CSeqMethod = SIPMethodsEnum.ACK;
header.AuthenticationHeader = TransactionRequest.Header.AuthenticationHeader;
header.ProxySendFrom = base.TransactionRequest.Header.ProxySendFrom;
// If the UAS supplies a desired Record-Route list use that first. Otherwise fall back to any Route list used in the original transaction.
if (sipResponse.Header.RecordRoutes != null)
{
header.Routes = sipResponse.Header.RecordRoutes.Reversed();
}
else if (base.TransactionRequest.Header.Routes != null)
{
header.Routes = base.TransactionRequest.Header.Routes;
}
ackRequest.Header = header;
SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, CallProperties.CreateBranchId());
ackRequest.Header.Vias.PushViaHeader(viaHeader);
return(ackRequest);
}
/// <summary>
/// Used to create a SIP response for a request when it was not possible to parse the incoming SIP request.
/// The response generated by this method may or may not make it back to the requester. Because the SIP
/// request could not be parsed there are no Via headers available and without those the return network
/// path is missing. Instead a new Via header is generated that may get through if the requester is only
/// one SIP hop away.
/// </summary>
/// <param name="localSIPEndPoint">The local SIP end point the request was received on.</param>
/// <param name="remoteSIPEndPoint">The remote SIP end point the request was received on.</param>
/// <param name="responseCode">The response code to set on the response.</param>
/// <param name="reasonPhrase">Optional reason phrase to set on the response (keep short).</param>
public static SIPResponse GetResponse(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteSIPEndPoint,
SIPResponseStatusCodesEnum responseCode, string reasonPhrase)
{
try
{
SIPResponse response = new SIPResponse(responseCode, reasonPhrase);
response.SetSendFromHints(localSIPEndPoint);
SIPSchemesEnum sipScheme = (localSIPEndPoint.Protocol == SIPProtocolsEnum.tls)
? SIPSchemesEnum.sips
: SIPSchemesEnum.sip;
SIPFromHeader from = new SIPFromHeader(null, new SIPURI(sipScheme, localSIPEndPoint), null);
SIPToHeader to = new SIPToHeader(null, new SIPURI(sipScheme, localSIPEndPoint), null);
int cSeq = 1;
string callId = CallProperties.CreateNewCallId();
response.Header = new SIPHeader(from, to, cSeq, callId);
response.Header.CSeqMethod = SIPMethodsEnum.NONE;
response.Header.Vias.PushViaHeader(new SIPViaHeader(
new SIPEndPoint(localSIPEndPoint.Protocol, remoteSIPEndPoint.GetIPEndPoint()),
CallProperties.CreateBranchId()));
response.Header.MaxForwards = Int32.MinValue;
response.Header.Allow = m_allowedSIPMethods;
return(response);
}
catch (Exception excp)
{
logger.LogError("Exception SIPResponse.GetResponse. " + excp.Message);
throw;
}
}
/// <summary>
/// Duplicates an existing SIP request, typically one that received an unauthorised response, to an
/// authenticated version. The CSeq and Via branch ID are also incremented so
/// that the request will not be flagged as a retransmit.
/// </summary>
/// <param name="authenticationChallenges">The challenges to authenticate the request against. Typically
/// the challenges come from a SIP response.</param>
/// <param name="username">The username to authenticate with.</param>
/// <param name="password">The password to authenticate with.</param>
/// <returns>A SIP request that is a duplicate of the original but with an authentication header added and
/// the state header values updated so as not to be flagged as a retransmit.</returns>
public SIPRequest DuplicateAndAuthenticate(List <SIPAuthenticationHeader> authenticationChallenges,
string username,
string password)
{
var dupRequest = this.Copy();
dupRequest.Header.Vias.TopViaHeader.Branch = CallProperties.CreateBranchId();
dupRequest.Header.CSeq = dupRequest.Header.CSeq + 1;
dupRequest.Header.AuthenticationHeaders.Clear();
// RFC8760 (which introduces SHA256/512 for SIP) states that multiple authentication headers with different digest algorithms
// can be included in a SIP request. When testing this with the latest versions (Jul 2021) of Asterisk v18.5.0 and FreeSWITCH v1.10.6
// request authentication failed if the MD5 digest was not first and it's almost certain the subsequent SHA256 digest was ignored.
// As a consequence the logic below will only use a SHA256 digest IFF the UAS put an authentication challenge with the digest
// algorithm explicitly set to SHA-256.
// See https://github.com/sipsorcery-org/sipsorcery/issues/525.
bool useSHA256 = authenticationChallenges.Any(x => x.SIPDigest.DigestAlgorithm == DigestAlgorithmsEnum.SHA256);
if (useSHA256)
{
var sha256AuthHeader = SIPAuthChallenge.GetAuthenticationHeader(authenticationChallenges, this.URI, this.Method, username, password, DigestAlgorithmsEnum.SHA256);
dupRequest.Header.AuthenticationHeaders.Add(sha256AuthHeader);
}
else
{
var md5AuthHeader = SIPAuthChallenge.GetAuthenticationHeader(authenticationChallenges, this.URI, this.Method, username, password);
dupRequest.Header.AuthenticationHeaders.Add(md5AuthHeader);
}
return(dupRequest);
}
/// <summary>
/// New transaction ACK requests are for 2xx responses, i.e. INVITE accepted and dialogue being created.
/// </summary>
/// <remarks>
/// From RFC 3261 Chapter 17.1.1.3 - ACK for non-2xx final responses
///
/// IMPORTANT:
/// an ACK for a non-2xx response will also have the same branch ID as the INVITE whose response it acknowledges.
///
/// The ACK request constructed by the client transaction MUST contain
/// values for the Call-ID, From, and Request-URI that are equal to the
/// values of those header fields in the request passed to the transport
/// by the client transaction (call this the "original request"). The To
/// header field in the ACK MUST equal the To header field in the
/// response being acknowledged, and therefore will usually differ from
/// the To header field in the original request by the addition of the
/// tag parameter. The ACK MUST contain a single Via header field, and
/// this MUST be equal to the top Via header field of the original
/// request. The CSeq header field in the ACK MUST contain the same
/// value for the sequence number as was present in the original request,
/// but the method parameter MUST be equal to "ACK".
///
/// If the INVITE request whose response is being acknowledged had Route
/// header fields, those header fields MUST appear in the ACK. This is
/// to ensure that the ACK can be routed properly through any downstream
/// stateless proxies.
///
/// From RFC 3261 Chapter 13.2.2.4 - ACK for 2xx final responses
///
/// IMPORTANT:
/// an ACK for a 2xx final response is a new transaction and has a new branch ID.
///
/// The UAC core MUST generate an ACK request for each 2xx received from
/// the transaction layer. The header fields of the ACK are constructed
/// in the same way as for any request sent within a dialog (see Section
/// 12) with the exception of the CSeq and the header fields related to
/// authentication. The sequence number of the CSeq header field MUST be
/// the same as the INVITE being acknowledged, but the CSeq method MUST
/// be ACK. The ACK MUST contain the same credentials as the INVITE. If
/// the 2xx contains an offer (based on the rules above), the ACK MUST
/// carry an answer in its body. If the offer in the 2xx response is not
/// acceptable, the UAC core MUST generate a valid answer in the ACK and
/// then send a BYE immediately.
/// </remarks>
private SIPRequest GetNewTransactionACKRequest(SIPResponse sipResponse, SIPURI ackURI, SIPEndPoint localSIPEndPoint)
{
SIPRequest ackRequest = new SIPRequest(SIPMethodsEnum.ACK, ackURI.ToString());
ackRequest.LocalSIPEndPoint = localSIPEndPoint;
SIPHeader header = new SIPHeader(TransactionRequest.Header.From, sipResponse.Header.To, sipResponse.Header.CSeq, sipResponse.Header.CallId);
header.CSeqMethod = SIPMethodsEnum.ACK;
header.AuthenticationHeader = TransactionRequest.Header.AuthenticationHeader;
header.ProxySendFrom = base.TransactionRequest.Header.ProxySendFrom;
if (sipResponse.Header.RecordRoutes != null)
{
header.Routes = sipResponse.Header.RecordRoutes.Reversed();
}
ackRequest.Header = header;
SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, CallProperties.CreateBranchId());
ackRequest.Header.Vias.PushViaHeader(viaHeader);
return(ackRequest);
}
/// <summary>
/// Helper method to create a SIP response for a SIP request. This method can be thought of as creating a
/// vanilla (or no frills) response for a request. It's suitable for generating error responses. For requests that
/// require an action such as creating a call or registering a contact the response will require additional
/// information and this method will not be suitable.
/// </summary>
/// <param name="sipRequest">The SIP request to create the response for.</param>
/// <param name="responseCode">The response code.</param>
/// <param name="reasonPhrase">Optional reason phrase to set on the response (needs to be short).</param>
/// <returns>A SIP response object.</returns>
public static SIPResponse GetResponse(SIPRequest sipRequest, SIPResponseStatusCodesEnum responseCode,
string reasonPhrase)
{
try
{
SIPResponse response = new SIPResponse(responseCode, reasonPhrase);
response.SetSendFromHints(sipRequest.LocalSIPEndPoint);
if (reasonPhrase != null)
{
response.ReasonPhrase = reasonPhrase;
}
SIPHeader requestHeader = sipRequest.Header;
SIPFromHeader from = (requestHeader == null || requestHeader.From != null)
? requestHeader.From
: new SIPFromHeader(null, new SIPURI(sipRequest.URI.Scheme, sipRequest.LocalSIPEndPoint), null);
SIPToHeader to = (requestHeader == null || requestHeader.To != null)
? requestHeader.To
: new SIPToHeader(null, new SIPURI(sipRequest.URI.Scheme, sipRequest.LocalSIPEndPoint), null);
int cSeq = (requestHeader == null || requestHeader.CSeq != -1) ? requestHeader.CSeq : 1;
string callId = (requestHeader == null || requestHeader.CallId != null)
? requestHeader.CallId
: CallProperties.CreateNewCallId();
response.Header = new SIPHeader(from, to, cSeq, callId);
response.Header.CSeqMethod = (requestHeader != null) ? requestHeader.CSeqMethod : SIPMethodsEnum.NONE;
if (requestHeader == null || requestHeader.Vias == null || requestHeader.Vias.Length == 0)
{
response.Header.Vias.PushViaHeader(new SIPViaHeader(sipRequest.RemoteSIPEndPoint,
CallProperties.CreateBranchId()));
}
else
{
response.Header.Vias = requestHeader.Vias;
}
response.Header.MaxForwards = Int32.MinValue;
response.Header.Allow = m_allowedSIPMethods;
return(response);
}
catch (Exception excp)
{
logger.LogError("Exception SIPResponse.GetResponse. " + excp.Message);
throw excp;
}
}
public string CreateBranchId()
{
string routeStr = (Header.Routes != null) ? Header.Routes.ToString() : null;
string toTagStr = (Header.To != null) ? Header.To.ToTag : null;
string fromTagStr = (Header.From != null) ? Header.From.FromTag : null;
string topViaStr = (Header.Vias != null && Header.Vias.TopViaHeader != null) ? Header.Vias.TopViaHeader.ToString() : null;
return(CallProperties.CreateBranchId(
SIPConstants.SIP_BRANCH_MAGICCOOKIE,
toTagStr,
fromTagStr,
Header.CallId,
URI.ToString(),
topViaStr,
Header.CSeq,
routeStr,
Header.ProxyRequire,
null));
}
private SIPRequest GetByeRequest(SIPEndPoint localSIPEndPoint)
{
SIPRequest byeRequest = new SIPRequest(SIPMethodsEnum.BYE, RemoteTarget);
SIPFromHeader byeFromHeader = SIPFromHeader.ParseFromHeader(LocalUserField.ToString());
SIPToHeader byeToHeader = SIPToHeader.ParseToHeader(RemoteUserField.ToString());
int cseq = CSeq + 1;
SIPHeader byeHeader = new SIPHeader(byeFromHeader, byeToHeader, cseq, CallId);
byeHeader.CSeqMethod = SIPMethodsEnum.BYE;
byeRequest.Header = byeHeader;
byeRequest.Header.Routes = RouteSet;
byeRequest.Header.ProxySendFrom = ProxySendFrom;
SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, CallProperties.CreateBranchId());
byeRequest.Header.Vias.PushViaHeader(viaHeader);
return(byeRequest);
}
private SIPRequest GetDummyINVITERequest(SIPURI dummyURI)
{
string dummyFrom = "<sip:[email protected]>";
string dummyContact = "sip:127.0.0.1:1234";
SIPRequest inviteRequest = new SIPRequest(SIPMethodsEnum.INVITE, dummyURI);
SIPHeader inviteHeader = new SIPHeader(SIPFromHeader.ParseFromHeader(dummyFrom), new SIPToHeader(null, dummyURI, null), 1, CallProperties.CreateNewCallId());
inviteHeader.From.FromTag = CallProperties.CreateNewTag();
inviteHeader.Contact = SIPContactHeader.ParseContactHeader(dummyContact);
inviteHeader.CSeqMethod = SIPMethodsEnum.INVITE;
inviteHeader.UserAgent = "unittest";
inviteRequest.Header = inviteHeader;
SIPViaHeader viaHeader = new SIPViaHeader("127.0.0.1", 1234, CallProperties.CreateBranchId(), SIPProtocolsEnum.udp);
inviteRequest.Header.Vias.PushViaHeader(viaHeader);
inviteRequest.Body = "dummy";
inviteRequest.Header.ContentLength = inviteRequest.Body.Length;
inviteRequest.Header.ContentType = "application/sdp";
return(inviteRequest);
}
