Abstract:
A method of performing network communications includes receiving a datagram for transmitting information over a network, selecting a layer in a network protocol stack to establish communication over the network using an inner layer application programming interface (IL API), establishing an inner layer socket at the selected network layer using the IL API without accessing other layers in the layered network protocol stack, and transmitting the datagram packet over the selected layer using the inner layer socket.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of computer data networking and an interface method and system for accessing inner layers of a network protocol. 
     BACKGROUND OF THE INVENTION 
     The use of layered data communications protocols promotes system interoperability, vendor portability and simplicity in system integration. Each protocol layer operates at a different layer of abstraction and performs different types of data manipulation and formatting. Because each layer is concerned with events at its own level of abstraction, different software designers can work together to design the protocols. Layers of the network protocol can also be replaced individually without significant communication incompatibilities problems arising. 
     The Internet Protocol (IP) stack is a widely used layered communication protocol. Applications use the IP stack to transmit and receive data over a variety of different local and wide area networks. Typically, a transmitting application passes application data to a transport layer in the IP stack, which in turn adds routing information to the data and passes the results to a data link layer. The data link layer also adds additional header information and passes the resulting information to a physical layer, where it is finally transmitted over the network. 
     A receiving application associated with a receiving IP stack receives and processes the information. Each layer of the receiving IP stack performs various communication functions and format conversions in reverse going from the physical layer, the data link layer, the network layer, the transport layer, and then to the receiving application. In a conventional network, applications send and receive messages from each other and use the IP stack as a conduit for data. Notwithstanding these messages, other information being transmitted between the sending and receiving IP stacks is not typically made available to either the sending or receiving applications. 
     While layered protocols such as used in a conventional IP stack have some advantages, they are have been obtained by lowering programmatic flexibility. For example, application data is encapsulated with protocol-generated headers whose content cannot be accessed and controlled by the application itself. Applications are masked from the inner operation of a network protocol and network operation. This inflexibility makes it difficult for an application to send data encapsulated with a non-standard header when required or monitor operation of the network. 
     SUMMARY OF THE INVENTION 
     A method of performing network communications includes receiving a datagram for transmitting information over a network, selecting a layer in a network protocol stack to establish communication over the network using an inner layer application programming interface (IL API), establishing an inner layer socket at the selected network layer using the IL API without accessing other layers in the layered network protocol stack, and transmitting the datagram packet over the selected layer using the inner layer socket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and aspects of the present invention will become more fully apparent from the following detailed description, appended claims, and accompanying drawings in which: 
         FIG. 1  is a block diagram illustrating a network using an inner layer application programming interface (IL API) to communicate between nodes on the network. 
         FIG. 2  is a block diagram demonstrating the various protocols an application can interface with using the IL API. 
         FIG. 3  is a block diagram illustrating how the IL API works to provide access to the Internet Protocol (IP) stack. 
       FIG.  4 . is a block diagram depicting a computer system that provides the IL API and IP stack to applications. 
         FIG. 5  is a flow-chart diagram illustrating the operations associated with communicating over the IP stack using the IL API. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a block diagram illustrating a network  100  using an inner layer application programming interface (IL API) to communicate between nodes on network  100 . Network  100  includes a transmit application  102  with a corresponding TCP/IP stack  104 , a data link layer  106  and a inner layer application programming interface (IL API)  108  facilitating communication between transmit application  102  and layers within TCP/IP stack  104 . Further, network  100  also includes a first intermediate gateway or router node represented by IP stack  1110  and data link layer  112  and a second intermediate gateway or router node represented by IP stack  114  and data link layer  116 . Receive application  118  in network  100  has a TCP/IP stack  120 , data link layer  122  and a IL API  124 . Physical connection  126  provides a connection to each of these nodes through their respective data link layers using a physical access protocol such as CSMA/CD. 
     Conventional layered communications provides applications with application to application or peer-to-peer or communication capabilities. Information at the lower layers of the protocol stack are masked from the application through abstract interfaces. This simplifies network programming over the IP stack but does not provide much flexibility if access to these other layers is desired. IL API  108  and IL API  124  provides this communication capability to both transmit application  102  and receive application  118 . For example, transmit application  102  and receive application  118  have access to IP stack  110  and IP stack  114  directly using their respective IL API. Additionally, transmit application  102  and receive application  118  also have access to other protocol layers using the IL API such as data link layer  112  and data link layer  116 . 
       FIG. 2  illustrates many different types of network information available at these different layers in the protocol stack. This block diagram illustrates an application  202  passing through an IL API  204  to gain access to a transport layer  206 , a network layer  208 , and a data link layer  210 . At transport layer  206 , application  202  has access to the transport protocols TCP  212 , UDP  214 , and other transport  216 . TCP  212  or Transmission Control Protocol is a connection-oriented protocol that provides a reliable, full-duplex, byte stream for a user process. Most conventional Internet applications use TCP  212  and allow TCP  212  to interface with the IP layers below. UDP  212  or User Datagram Protocol is a connectionless protocol also for user processes, however, it does not guarantee that UDP datagrams will ever reach their intended destination. Because TCP and UDP both access the IP layer the protocol is often referred to as simply TCP/IP. 
     Network layer  208  provides application  202  with access through IL API  204  to information carried over Appletalk  218 , IPv 4   220 , IPv 6   222 , and IPX  224 . These protocols provide packet delivery services and routing capabilities for transport protocols such as TCP  212  and UDP  214 . Networks based on Appletalk  218  and IPX  224  can be integrated to work with the TCP and UDP transport protocols. In addition, routers, switches, hubs and other network devices exchange status and network routing information describing network layer resources using ICMP (Internet Control Message Protocool) and IGMP (Internet Gateway Message Protocol). Appletalk  218  provides packet delivery services primarily to computers designed by Apple Computer of Cupertino, Calif. IPv 4   220  (version 4) provides 32-bit addresses and IPv 6   222  (version 6) provides 64-bit addresses in the Internet Protocol (IP) defined in specification DOD-STD-1777. Further references to the IP protocol include these additional protocols described above. 
     Application  202  also has access to data link layer  210  through IL API  204 . Fiber distributed data interface (FDDI) protocol  226  is a standard for data transmission on fiber optic lines in a local area network that can extend in range up to 200 km (124 miles). FDDI protocol  226  is based on the token ring protocol and in addition can support thousands of users. In addition, application  202  can also access information from Ethernet  228  through IL API  204 . Ethernet  228  is the most widely-installed local area network technology and specifies sharing physical access over coaxial cable or special grades of twisted pair wires (10BASE-T) providing transmission speeds from several Mbps to Gbps. Devices are connected to the cable and compete for access using a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol. 
       FIG. 3  is a block diagram illustrating how the IL API works to provide access to a Internet Protocol (IP) stack  300 . IP stack  300  includes application  302 , transport layer  304 , network layer  306 , data link layer  308  each connected to IL API  312 . In one implementation, layers in IP stack  300  produce an Ethernet packet  310  with a data payload and headers from each of the various layers. 
     In conventional network communication, application  314  and application  316  communicate through either TCP  318  or UDP  320  for connection or connectionless type communication over a network. As an alternative, both application  314  and application  316  can communicate with transport layer  304  through TCP Socket  334  in IL API  312 . Although, additional information is not available, a more uniform implementation is achieved by offering the transport interface with IL API  312 . 
     Application  314  and application  316  can use IL API  312  to access network layer  306  and data link layer  308  in ways previously unavailable. For example, application  314  can access Internet Control Message Protocol (ICMP)/Internet Group Multicast Protocol (IGMP)  324  resources and interact with routers, switches, hubs, gateways, and hosts communicating with each other about errors and system control. ICMP provides message control and error-reporting protocol between a host server and a gateway to the Internet. ICMP uses Internet Protocol (IP) datagrams that IL API  312  provides to an application. On conventional systems, this information is processed by the TCP/IP protocol and is not available directly to the application. IGMP is used to support multicasting between nodes on a network and provides resources to applications through IL API  312  in a similar manner. Application  314  also has access to ARP  326  and RARP  328  resources. Application  314  opens a socket using IP Socket  336  interface and establishes a direct connection with network layer  306 . Because application  314  bypasses transport layer  318 , ARP  326  and RARP  328  resources are exposed and available for application  314  to process. For example, ARP  326  resources include Media Access Control (MAC) addresses associated with each Ethernet device on a network. 
     Application  314  operates in a similar manner with respect to data link layer  308 . To gain access to data link layer  308 , application  314  establishes a session directly to data link layer  308  through link socket  338 . Once the session through link socket  338  is created, application  314  has access to resources in data link  330  and physical layer  332 . For example, application  314  can create customized headers for an Ethernet packet  310  creating TCP Header and IP Header as illustrated in Ethernet packet  310  in FIG.  3 . Ethernet header and Ethernet trailer are added by an Ethernet type data link  330 . This provides an application with additional flexibility when developing network management software or developing text routines that need access to lower layers of the network protocol stack. 
     FIG.  4 . is a block diagram depicting a computer system  400  that provides the IL API and IP stack to applications. Computer system includes a memory  402 , a processor  404 , a network communication port  406 , a secondary storage  408 , and input-output ports  410 . Processor can be a general-purpose processor such as manufactured by Intel Corporation of Santa Clara Calif. or can be a specialized ASIC or other type of processor device. Network communication port  406  can be implemented as a Ethernet card or built-in communication port on a computer and secondary storage  408  is a hard-disk, CDROM, or other mass storage device. Input-output ports includes ports for corresponding peripheral devices such as keyboard, mouse, printer, display, and scanner. 
     Memory  402  includes an application  414 , an inner layer API (IL API)  416 , inner layer extensions  418 , virtual machine runtime environment  420 , TCP/IP protocol  422 , network resources  423  and operating system  424 . Application  414  is an application that can access one or more different layers of a network protocol stack such as TCP/IP protocol  422 . Generally, application  414  should be a user application but may need to be run with increased permissions such as “root” or “superuser” due to the sensitive information accessible within the inner layers of TCP/IP protocol  422 . 
     Inner layer API  416  is the interface routines linked into application  414  that provides direct access to the transport, the network, data link layers and physical layers in the protocol stack. Inner layer extensions  418  include any supporting routines necessary to make the IL API  416  available on the given platform. In some cases, this could involve recompiling an operating system kernel to include these particular functionalities not previously available to applications. In an object-oriented implementation, such as using the Java programming language by Sun Microsystems of Mountain View, Calif., these extensions can be dynamically loaded at run-time or immediately when they are loaded into the overall system. Because Java allows dynamic loading of routines, inner layer extensions  418  can be loaded as application  414  requires. 
     Virtual machine runtime environment  420  is typically used with an object-oriented programming language such as Java. If a non-object oriented or interpreted programming language is not being used, then virtual machine runtime environment  420  may not be required. For Java, a Java Virtual Machine or JVM simulates a virtual machine and provides hardware independent computing capabilities in addition to dynamic loading of libraries, applications, and applets in real-time over a network. 
     TCP/IP  422  is the conventional layered protocol stack typically available on most computers and computer-like platforms. As previously mentioned, TCP/IP generally only provides applications with access to the transport layer but with IL API  416 , application  414  accesses the network layer, the data link layer, and the physical layer in addition to the transport layer. Network resources  423  represent the various tables and other network resources on a network device. These resources include information stored in routing tables, ARP tables, ICMP/IGMP related tables, tables for storing physical port information and any other tables or resources used to manage and or describe an aspect of a network device. 
     Operating system  424  manages resources on computer system  400  so they are used efficiently and uniformly. 
       FIG. 5  is a flow-chart diagram illustrating the operations associated with communicating over the IP stack using the IL API. Initially, an application creates a datagram to be transmitted over a network ( 502 ). The datagram or packet is self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network. The packet needs to be self-contained without reliance on earlier exchanges because there is no connection of fixed duration between the two communicating points as there is, for example, in most voice telephone conversations. This kind of protocol is therefore referred to as connectionless. 
     Given several layers to communicate with, application selects a network layer to establish communication ( 504 ). In part, the layer selected depends on the type of datagram the application has created. If the application creates a transport session using a transport socket such as TCP  334  in  FIG. 3 , the application provides the data and necessary headers. However, a network session uses a network socket such as IP Socket  446  in FIG.  3  and the application needs to create the appropriate network layer TCP header or UDP header around the data or payload section of each packet. Similarly, if the application creates a link layer session using link socket  338  then the application must also include IP header information in the packet. 
     The application also selects a layer in the network protocol stack depending on the layer a resource associated with the network device uses for communication. For example, the ICMP and IGMP tables are resources that use the IP protocol because they communicate that the network layer in the protocol stack. Similarly, an ARP table is a resource that uses the link layer to communicate information about the network device, in particular an Ethernet or MAC address of the network device. 
     The application then opens a socket at the selected layer of the network protocol using the IL API ( 506 ). Often, the communication occurs over a “raw” type of socket rather than a “cooked” socket. The information is considered raw because control characters and other information in the data stream are not stripped out or interpreted by other programs before being delivered to the application. For example, two common types of packets sent or received over raw sockets are ICMP packets and IGMP packets. Specific resources such as routing tables, ICMP and IGMP tables are identified with predetermined or well-known socket identifiers. Applications open an inner layer socket using these specific socket identifiers to access the information in these particular resources. Alternatively, the application can open inner layer sockets with other socket identifiers to intercept other types of information being transmitted across the particular network protocol layer. 
     Communication continues between the application and the selected layer or specific resource until the application ends or the connection is terminated ( 508 ). 
     In one implementation using the Java object-oriented programming environment, an application may contain source code that generates and utilizes Java link layer sockets as shown in the following code example A. 
     CODE EXAMPLE A 
     
         
         
           
             Ethernet Packet ep=New Ethernet Packet (data, destination Ethernet Address); 
             Ethernet Socket s=New Ethernet Socket (source Ethernet Address); 
             Byte size; 
             Byte buffer=new byte[size];
           s.send(ep);   s.rcv(buf);   
         
           
         
       
    
     The Code Example A details the use of a combination send/receive Java link layer socket “s” whose address is “source Ethernet Address”. A datagram packet “ep” is created for use in an Ethernet networking environment, where “ep” is intended to be sent to a destination “destination Ethernet Address”. A receive buffer “buf” is created for socket “s”, and given size “size”. After “ep” is sent by Java link layer socket “s”, Java link layer socket “s” receives any return packets in buffer “buf”. 
     Another example of the use of Java link layer sockets is given below in code example B. 
     CODE EXAMPLE B 
     
         
         
           
             Ethernet Address destination=new Ethernet Address; 
             Ethernet Address source=new Ethernet Address; 
             Byte [ ] buf=new byte [2000]; 
             Ethernet Packet ep=new Ethernet Packet (buf, destination);
           // put the data into the buffer buf   
         
             Ethernet Socket es=new Ethernet Socket (source); 
             es.send(ep); 
             es.receive(ep);
 
// now look at data in the buffer buf
 
           
         
       
    
     In the code example B, a buffer “buf” is utilized as a bi-directional send/receive buffer for supporting the socket “es”. 
     While specific implementations have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. For example, implementations and examples are provided with reference to TCP/IP however, an alternate implementation could also be adapted to work with the Open Systems Interconnection (OSI) network model. In the OSI communication model, IP is in layer  3 , and other layers are as illustrated in FIG.  3 . Inner sockets for the transport, network and data link layer are described but an inner socket for a physical layer could also be implemented. The physical layer would provide information about the ports on a network device and information about the physical media being used. Additional implementations could be created using conventional procedural programming languages such as “C” as well as object-oriented programming environments/languages such as Java or C++. Furthermore, although aspects of the present invention are described as being stored in memory and other storage mediums, one skilled in the art will appreciate that these aspects can also be stored on or read from other types of computer-readable media, such as secondary storage devices, like hard disks, floppy disks, or CD-ROM; a carrier wave from the Internet; or other forms of RAM or ROM. Accordingly, the invention is not limited to the above-described embodiments, but instead is defined by the appended claims in light of their full scope of equivalents.