Namespace SipLib.Core

Core classes for building and parsing SIP messages.

The main classes in the SipLib.Core namespace are:

SIPMessage
SIPRequest
SIPResponse
SIPHeader
Classes for each type of SIP header (SIPFrom, SIPTo, etc.)

The SIPMessage class is the base class for the SIPRequest (representing a SIP request message) and the SIPResponse (representing a SIP response message) classes. The SIPMessage class contains SIP headers and optionally a SIP message body. The Header field of a SIPMessage is a SIPHeader object that contains fields for the SIP headers. Each type of SIP header is represented by a unique class. For example, the SIPFromHeader class is used to manage a SIP From header. The SIPMessage class contains methods and properties for accessing the contents of the body of a SIP message if one is present.

When building applications that receive and process SIP message, it is generally not necessary to programmatically parse raw messages received via the network because message parsing is handled by classes contained in the SipLib.Channels and SipLib.Transactions namespaces.

The SipUtils class in the SipLib.Core namespace is a static class that provides various helper methods for building SIP messages and for extracting various information from SIP messages.

Classes

ByteBufferInfo

Class for parsing a buffer of bytes

CallProperties

Class that provides various static utility functions relating to call properties

Crypto

Class containing various cryptography utilities

HTTPDigest

Class for processing an HTTP digest

IPSocket

Class containing various utility functions for sockets.

SIPAuthenticationHeader

Class for the SIP WWW-Authenticate and Authorization headers

SIPAuthorisationDigest

Class for the SIP authorization digest

SIPCallInfoHeader

Class for a SIP Call-Info header. See Sections 20.9 and 25.1 of RFC 3261.

SIPConstants

Defines various constants used for SIP

SIPContactHeader

Class for building or parsing a SIP Contact header. See Section 20.10 and page 228 of RFC 3261.

SIPEndPoint

This class is a more specific version of the SIPURI class BUT is only concerned with the network and transport properties. It contains all the information needed to determine the remote end point to deliver a SIP request or response to.

This class must remain immutable otherwise the SIP stack can develop problems. SIP end points can get passed amongst different servers for logging and forwarding SIP messages and a modification of the end point by one server can result in a problem for a different server. Instead a new SIP end point should be created wherever a modification is required.

SIPEscape

Static class that contains various methods for escaping and unescaping reserved characters in various parts of SIPURIs, SIP headers, SIP parameters, etc.

SIPFrag

Class for parsing or creating a SIPFRAG (SIP Fragment) body use in a NOTIFY request for a Refer subscription. See Section 2.4.5 of RFC 3515.

SIPFromHeader

The From header only has parameters, no headers. Parameters of from ...;name=value;name2=value2. Specific parameters: tag.

SIPGeolocationHeader

Class for a SIP Geolocation header as defined in RFC 6442.

SIPHeader

Class for handling the SIP headers portion of a SIP request or a SIP response message.

SIPHeaders

Definitions for SIP Header fields.

SIPMessage

Represents an entire SIP message. This is the base class for the SIPRequest and the SIPResponse classes.

SIPMethods

Class for mapping SIP method string to SIPMethodsEnum values

SIPPaiHeader

Class for the SIP P-Asserted-Identity header.

SIPParameters

Represents a series of name value pairs that are optionally included in SIP URIs and also as an additional optional setting on some SIP Headers (Contact, To, From, Via). This class also treats the header value of a SIP URI as a special case of a SIP parameter. The difference between a parameter and a SIP URI header is the start and delimiter characters used.

SIPPpiHeader

Class for the SIP P-Preferred-Identity header.

SIPProtocolsType

Helper functions for dealing with tranport protocols

SIPReplacesParameter

Class for the Replaces parameter of a Refer-To header field. The Replaces parameter is used to identify involved in a transfer operation.

SIPRequest

Class for a SIP request message.

SIPResponse

Class for a SIP Response message

SIPResponseStatusCodes

SIP response status codes functions

SIPRoute

The SIPRoute class is used to represent both Route and Record-Route headers.

SIPRouteSet

Class for managing a SIP Route set

SIPSchemesType

Helper functions for dealing with SIP schemes

SIPToHeader

Class for handling a SIP To header

SIPURI

Implements the SIP URI concept from the SIP RFC3261. This class also handles URIs for http, https, ws, wss, msrp, msrps and im schemes.

SIPUserField

Class for parsing and building the user field of a SIP URI.

SIPValidationException

Exception class for SIP validation errors

SIPViaHeader

The Via header only has parameters, no headers. Parameters of from ...;name= value;name2=value2 Specific parameters: ttl, maddr, received, branch.

From page 179 of RFC3261: "Even though this specification mandates that the branch parameter be present in all requests, the BNF for the header field indicates that it is optional."

The branch parameter on a Via therefore appears to be optionally mandatory?!

Any SIP application element that uses transactions depends on the branch parameter for transaction matching. Only the top Via header branch is used for transactions though so if the request has made it to this stack with missing branches then in theory it should be safe to proceed. It will be left up to the SIPTransaction class to reject any SIP requests that are missing the necessary branch.

Namespace SipLib.Core

Classes

Enums