private ViaEntry(ViaEntry entry)
{
Protocol = entry.Protocol;
SipVersion = entry.SipVersion;
Transport = entry.Transport;
Domain = entry.Domain;
foreach (var pair in entry._parameters)
_parameters.Add(pair.Key, pair.Value);
}
private ViaEntry(ViaEntry entry)
{
Protocol = entry.Protocol;
SipVersion = entry.SipVersion;
Transport = entry.Transport;
Domain = entry.Domain;
foreach (var pair in entry._parameters)
{
_parameters.Add(pair.Key, pair.Value);
}
}
public static ViaEntry ParseEntry(ITextReader reader)
{
//SIP/2.0/UDP erlang.bell-telephone.com:5060;branch=z9hG4bK87asdks7
var entry = new ViaEntry();
// read SIP/
reader.ConsumeWhiteSpaces();
entry.Protocol = reader.ReadUntil("/ \t");
if (entry.Protocol == null)
throw new FormatException("Expected Via header to start with 'SIP' or 'SIPS'.");
reader.ConsumeWhiteSpaces('/');
// read 2.0/
entry.SipVersion = reader.ReadUntil("/ \t");
if (entry.SipVersion == null)
throw new FormatException("Expected to find sip version in Via header.");
reader.ConsumeWhiteSpaces('/');
// read UDP or TCP
entry.Transport = reader.ReadWord();
if (entry.Transport == null)
throw new FormatException("Expected to find transport protocol after sip version in Via header.");
reader.ConsumeWhiteSpaces();
entry.Domain = reader.ReadUntil(";: \t");
if (entry.Domain == null)
throw new FormatException("Failed to find domain in via header.");
reader.ConsumeWhiteSpaces();
if (reader.Current == ':')
{
reader.Read();
reader.ConsumeWhiteSpaces();
string temp = reader.ReadToEnd("; \t");
reader.ConsumeWhiteSpaces();
int port;
if (!int.TryParse(temp, out port))
throw new FormatException("Invalid port specified.");
entry.Port = port;
}
UriParser.ParseParameters(entry.Parameters, reader);
string rport = entry.Parameters["rport"];
if (!string.IsNullOrEmpty(rport)) //parameter can exist, but be empty. = rport requested.
{
int value;
if (!int.TryParse(rport, out value))
throw new FormatException("RPORT is not a number.");
entry.Rport = value;
}
return entry;
}
/// <summary>
/// Create a new request
/// </summary>
/// <param name="method">Sip method.</param>
/// <param name="from">Who is dialing?</param>
/// <param name="to">Destination</param>
/// <returns>Request object.</returns>
/// <seealso cref="SipMethod"/>
public IRequest CreateRequest(string method, Contact from, Contact to)
{
// A valid SIP request formulated by a UAC MUST, at a minimum, contain
// the following header fields: To, From, CSeq, Call-ID, Max-Forwards,
// and Via; all of these header fields are mandatory in all SIP
// requests. These six header fields are the fundamental building
// blocks of a SIP message, as they jointly provide for most of the
// critical message routing services including the addressing of
// messages, the routing of responses, limiting message propagation,
// ordering of messages, and the unique identification of transactions.
// These header fields are in addition to the mandatory request line,
// which contains the method, Request-URI, and SIP version.
// The initial Request-URI of the message SHOULD be set to the value of
// the URI in the To field. One notable exception is the REGISTER
// method; behavior for setting the Request-URI of REGISTER is given in
// Section 10.
var request = new Request(method, from.Uri, "SIP/2.0");
request.From = from;
// A request outside of a dialog MUST NOT contain a To tag; the tag in
// the To field of a request identifies the peer of the dialog. Since
// no dialog is established, no tag is present.
// For further information on the To header field, see RFC 3261 Section 20.39.
request.To = to;
// The Call-ID header field acts as a unique identifier to group
// together a series of messages. It MUST be the same for all requests
// and responses sent by either UA in a dialog. It SHOULD be the same
// in each registration from a UA.
// In a new request created by a UAC outside of any dialog, the Call-ID
// header field MUST be selected by the UAC as a globally unique
// identifier over space and time unless overridden by method-specific
// behavior. All SIP UAs must have a means to guarantee that the Call-
// ID header fields they produce will not be inadvertently generated by
// any other UA.
request.CallId = CreateCallId();
// The CSeq header field serves as a way to identify and order
// transactions. It consists of a sequence number and a method. The
// method MUST match that of the request. For non-REGISTER requests
// outside of a dialog, the sequence number value is arbitrary. The
// sequence number value MUST be expressible as a 32-bit unsigned
// integer and MUST be less than 2**31. As long as it follows the above
// guidelines, a client may use any mechanism it would like to select
// CSeq header field values.
request.CSeq = new CSeq(GetNextSequenceNumber(), method);
request.MaxForwards = 70;
// When the UAC creates a request, it MUST insert a Via into that
// request. The protocol name and protocol version in the header field
// MUST be SIP and 2.0, respectively. The Via header field value MUST
// contain a branch parameter. This parameter is used to identify the
// transaction created by that request. This parameter is used by both
// the client and the server.
//
// The branch parameter value MUST be unique across space and time for
// all requests sent by the UA. The exceptions to this rule are CANCEL
// and ACK for non-2xx responses. As discussed below, a CANCEL request
// will have the same value of the branch parameter as the request it
// cancels. As discussed in Section 17.1.1.3, an ACK for a non-2xx
// response will also have the same branch ID as the INVITE whose
// response it acknowledges.
//
// The uniqueness property of the branch ID parameter, to facilitate
// its use as a transaction ID, was not part of RFC 2543.
//
// The branch ID inserted by an element compliant with this
// specification MUST always begin with the characters "z9hG4bK". These
// 7 characters are used as a magic cookie (7 is deemed sufficient to
// ensure that an older RFC 2543 implementation would not pick such a
// value), so that servers receiving the request can determine
// specification (that is, globally unique). Beyond this requirement,
// the precise format of the branch token is implementation-defined.
//
// The Via header maddr, ttl, and sent-by components will be set when
// the request is processed by the transport layer (Section 18).
//
// Via processing for proxies is described in Section 16.6 Item 8 and
// Section 16.7 Item 3.
var viaEntry = new ViaEntry(_endPoint.Address.ToString(), CreateBranch());
viaEntry.RportWanted = true;
request.Via.Add(viaEntry);
// The Contact header field provides a SIP or SIPS URI that can be used
// to contact that specific instance of the UA for subsequent requests.
// The Contact header field MUST be present and contain exactly one SIP
// or SIPS URI in any request that can result in the establishment of a
// dialog. For the methods defined in this specification, that includes
// only the INVITE request. For these requests, the scope of the
// Contact is global. That is, the Contact header field value contains
// the URI at which the UA would like to receive requests, and this URI
// MUST be valid even if used in subsequent requests outside of any
// dialogs.
//
// If the Request-URI or top Route header field value contains a SIPS
// URI, the Contact header field MUST contain a SIPS URI as well.
request.Contact = _contact;
return request;
}
