WO2001043329A2

WO2001043329A2 - Enabling simultaneous provision of infrastructure services

Info

Publication number: WO2001043329A2
Application number: PCT/US2000/042641
Authority: WO
Inventors: Germano Caronni; Amit Gupta; Tom R. Markson; Sandeep Kumar; Christoph L. Schuba; Glenn C. Scott
Original assignee: Sun Microsystems, Inc.
Priority date: 1999-12-10
Filing date: 2000-12-08
Publication date: 2001-06-14
Also published as: AU4519701A; WO2001043329A3

Abstract

Methods and systems consistent with the present invention include unique addressing structures and security services in the network layer of the OSI model. This provides an environment in which remote nodes may communicate securely with one another regardless of the infrastructure services used. The remote nodes may join a group identified by a channel number to properly authenticate one another.

Description

ENABLING SIMULTANEOUS PROVISION OF INFRASTRUCTURE SERVICES

FIELD OF THE INVENTION The present invention relates generally to data processing systems and, more particularly, to a private network using a public-network infrastructure.

BACKGROUND OF THE INVENTION

As part of their day-to-day business, many organizations require an enterprise network, a private network with lease lines, dedicated channels, and network connectivity devices, such as routers, switches, and bridges. These components, collectively known as the network's "infrastructure," are very expensive and require a staff of information technology personnel to maintain them. This maintenance requirement is burdensome on many organizations whose main business is not related to the data processing industry (e.g., a clothing manufacturer) because they are not well suited to handle such data processing needs.

Another drawback to enterprise networks is that they are geographically restrictive. The term "geographically restrictive" refers to the requirement that if a user is not physically located such that they can plug their device directly into the enterprise network, the user cannot typically utilize it. To alleviate the problem of geographic restrictiveness, virtual private networks have been developed.

In a virtual private network (VPN), a remote device or network connected to the Internet may connect to the enterprise network through a firewall. This allows the remote device to access resources on the enterprise network even though it may not be located near any component of the enterprise network. For example, Fig. 1 depicts a VPN 100, where enterprise network 102 is connected to the Internet 104 via firewall 106. By using VPN 100, a remote device D, 108 may communicate with enterprise network 102 via Internet 104 and firewall 106. Thus, D, 108 may be plugged into an Internet portal virtually anywhere within the world and make use of the resources on enterprise network 102.

To perform this functionality, D, 108 utilizes a technique known as tunneling to ensure that the communication between itself and enterprise network 102 is secure in that it cannot be viewed by an interloper. "Tunneling" refers to encapsulating one packet inside another when packets are transferred between two end points (e.g., D, 108 and VPN software 109 running on firewall 106). The packets may be encrypted at their origin and decrypted at their destination. For example, Fig. 2A depicts a packet 200 with a source Internet protocol (IP) address 202, a destination IP address 204, and data 206. It should be appreciated that packet 200 contains other information not depicted, such as the source and destination port. As shown in Fig. 2B, the tunneling technique forms a new packet 208 out of packet 200 by encrypting it and adding both a new source IP address 210 and a new destination IP address 212. In this manner, the contents of the original packet (i.e., 202, 204, and 206) are not visible to any entity other than the destination. Referring back to Fig. 1, by using tunneling, remote device D* 108 may communicate and utilize the resources of the enterprise network 102 in a secure manner.

Although VPNs alleviate the problem of geographic restrictiveness, they impose significant processing overhead when two remote devices communicate. For example, if remote device D* 108 wants to communicate with remote device D₂ 110. D, sends a packet using tunneling to VPN software 109, where the packet is decrypted and then transferred to the enterprise network 102. Then, the enterprise network 102 sends the packet to VPN software 109, where it is encrypted again and transferred to D₂ Given this processing overhead, it is burdensome for two remote devices to communicate in a VPN environment.

One encryption method used in VPNs is IPSec. IPSec acts at the network layer of the OSI model, protecting and authenticating IP packets between participating IPSec devices, such as routers. IPSec supports both transport and tunnel encryption modes in VPNs. Transport mode encrypts only the data portion (payload) of each packet, but leaves the header untouched. The more secure tunnel mode encrypts both the header and the payload. IPSec is described in greater detail in http://www.ietf.cnri.reston.va.us/html.charters/ipsec-charter.html. The OSI model is a well-known model used to describe the seven protocol layers in a standard TCP/IP protocol stack. The OSI model contains seven layers that use various forms of control information to communicate with their peer layers in other computer systems. This control information consists of specific requests and instructions that are exchanged between peer layers. Although the IPSec protocol provides a standard, secure way to communicate with participating known nodes in a VPN using the TCP/IP protocol, it does not integrate with other infrastmcture services, such as Network Address Translators (NAT), SOCKS, Mobile IP, or Dynamic Host Configuration Protocol (DHCP). SOCKS is a security package that allows a host behind a firewall to use finger or telnet to access resources outside the firewall while maintaining the security requirements. DHCP provides a dynamic addressing scheme that provides a node with a new address each time the node connects to the Internet. In fact, these services usually support antagonistic goals. For example, IPSec cannot not integrate with nodes using DHCP. The security association would need to be reestablished since the IP address used in the IP header is bound to the node's real IP address.

Therefore, it is desirable to provide a secure protocol that can easily integrate and support existing infrastructure services.

SUMMARY OF THE INVENTION Methods and systems consistent with the present invention overcome the shortcomings of existing protocols by including unique addressing structures and security services in the network layer of the OSI model. This provides an environment in which remote nodes may communicate securely with one another regardless of the infrastructure services used. The remote nodes may join a group identified by a channel number to properly authenticate one another.

In accordance with the purpose of the invention as embodied and broadly described herein, a method is provided for transmitting a message from a source to a destination. The method receives an IP packet from the source that contains a virtual IP address corresponding to the source, requests a real IP address that corresponds to the virtual IP address, encapsulates the existing IP packet by prepending a header that contains the real IP address to the existing IP packet; and transmits the encapsulated IP packet to the destination associated with the real IP address.

In another implementation, a method is provided for communicating with a mobile device in a public network. The method requests a real destination IP address that translates to a virtual destination IP address from an address server, and encapsulates the IP packet by prepending a header that contains the real IP address to a IP packet. Additionally, the method transmits the encapsulated IP packet to the mobile device.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention is pointed out with particularity in the appended claims. The above and further advantages of this invention may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 depicts a conventional virtual private network (VPN) system;

Fig. 2A depicts a conventional network packet;

Fig. 2B depicts the packet of Fig. 2A after it has been encrypted in accordance with a conventional tunneling technique;

Fig. 3 depicts a data processing system suitable for use with methods and systems consistent with the present invention;

Fig. 4 depicts the nodes depicted in Fig. 3 communicating over multiple channels;

Fig. 5 depicts two devices depicted in Fig. 3 in greater detail;

Fig. 6 depicts an adapted OSI model used by a VPN in a manner consistent with the present invention;

Fig. 7 depicts a datagram packet used by the OSI model of Fig. 6;

Figs. 8A and 8B depict a flow chart of the steps performed when a VPN in a manner consistent with the present invention;

Fig. 8 depicts a flow chart of the steps performed when sending a packet from a node of the VPN in a manner consistent with the present invention;

Fig. 9 depicts a flow chart of the steps performed when receiving a packet by a node of the VPN in a manner consistent with the present invention; and

Fig. 10 depicts a flow chart of the steps performed when logging out of a Supernet.

Fig. 11 depicts an adapted OSI model used by a VPN in a manner consistent with the present invention; Fig. 12 depicts an embodiment of a mobile IP environment system for use with the invention.

DETAILED DESCRIPTION Methods and systems consistent with the present invention provide a "Supernet," which is a private network that uses components from a public-network infrastructure. A Supemet allows an organization to utilize a public-network infrastructure for its enterprise network so that the organization no longer has to maintain a private network infrastructure; instead, the organization may have the infrastructure maintained for them by one or more service providers or other organizations that specialize in such connectivity matters. As such, the burden of maintaining an enterprise network is greatly reduced. Moreover, a Supernet is not geographically restrictive, so a user may plug their device into the Internet from virtually any portal in the world and still be able to use the resources of their private network in a secure and robust manner.

Overview

Fig. 3 depicts a data processing system 300 suitable for use with methods and systems consistent with the present invention. Data processing system 300 comprises a number of devices, such as computers 302-312, connected to a public network, such as the Internet 314. A Supemet's infrastructure uses components from the Internet because devices 302, 304, and 312 contain nodes that together form a Supernet and that communicate by using the infrastructure of the Internet. These nodes 316, 318, 320, and 322 are communicative entities (e.g., processes) running within a particular device and are able to communicate among themselves as well as access the resources of the Supernet in a secure manner. When communicating among themselves, the nodes 316, 318, 320, and 322 serve as end points for the communications, and no other processes or devices that are not part of the Supemet are able to communicate with the Supemet's nodes or utilize the Supemet's resources. The Supemet also includes an administrative node 306 to administer to the needs of the Supemet. It should be noted that since the nodes of the Supemet rely on the Internet for connectivity, if the device on which a node is running relocates to another geographic location, the device can be plugged into an Internet portal and the node running on that device can quickly resume the use of the resources of the Supemet. It should also be noted that since a Supemet is layered on top of an existing network, it operates independently of the transport layer. Thus, the nodes of a Supemet may communicate over different transports, such as IP, IPX, X.25, or ATM, as well as different physical layers, such as RF communication, cellular communication, satellite links, or land- based links.

As shown in Fig. 4, a Supernet includes a number of channels that its nodes 316-322 can communicate over. A "channel" refers to a collection of virtual links through the public-network infrastmcture that connect the nodes on the channel such that only these nodes can communicate over it. A node on a channel may send a message to another node on that channel, known as a unicast message, or it can send a message to all other nodes on that channel, known as a multicast message. For example, channel 1 402 connects node A 316 and node C 320, and channel 2 404 connects node B 318, node C 320, and node D 322. Each Supernet has any number of preconfigured channels over which the nodes on that channel can communicate. In an alternative embodiment, the channels are dynamically defined.

In addition to communication, the channels may be used to share resources. For example, channel 1 402 may be configured to share a file system as part of node C 320 such that node A 316 can utilize the file system of node C in a secure manner. In this case, node C 320 serves as a file system manager by receiving file system requests (e.g., open, close, read, write, etc.) and by satisfying the requests by manipulating a portion of the secondary storage on its local machine. To maintain security, node C 320 stores the data in an encrypted form so that it is unreadable by others. Such security is important because the secondary storage may not be under the control of the owners of the Supemet, but may instead be leased from a service provider. Additionally, channel 2 404 may be configured to share the computing resources of node D 322 such that nodes B 318 and C 320 send code to node D for execution. By using channels in this manner, resources on a public network can be shared in a secure manner.

A Supemet provides a number of features to ensure secure and robust communication among its nodes. First, the system provides authentication and admission control so that nodes become members of the Supemet under strict control to prevent unauthorized access. Second, the Supemet provides communication security services so that the sender of a message is authenticated and communication between end points occurs in a secure manner by using encryption. Third, the system provides key management to reduce the possibility of an intruder obtaining an encryption key and penetrating a secure communication session. The system does so by providing one key per channel and by changing the key for a channel whenever a node joins or leaves the channel. Alternatively, the system may use a different security policy.

Fourth, the system provides address translation in a transparent manner. Since the Supernet is a private network constructed from the infrastructure of another network, the Supemet has its own internal addressing scheme, separate from the addressing scheme of the underlying public network. Thus, when a packet from a Supernet node is sent to another Supemet node, it travels through the public network. To do so, the Supernet performs address translation from the internal addressing scheme to the public addressing scheme and vice versa. To reduce the complexity of Supernet nodes, system-level components of the Supernet perform this translation on behalf of the individual nodes so that it is transparent to the nodes. Another benefit of the Supemet's addressing is that it uses an IP-based internal addressing scheme so that preexisting programs require little modification to run within a Supemet.

Lastly, the Supernet provides operating system-level enforcement of node compartmentalization in that an operating system-level component treats a Supernet node mnning on a device differently than it treats other processes on that device. This component (i.e., a security layer in a protocol stack) recognizes that a Supemet node is part of a Supernet, and therefore, it enforces that all communications to and from this node travel through the security infrastructure of the Supernet such that this node can communicate with other members of the Supemet and that non-members of the Supemet cannot access this node. Additionally, this operating system-level enforcement of node compartmentalization allows more than one Supemet node to run on the same machine, regardless of whether the nodes are from the same Supemet, and allows nodes of other networks to run on the same machine as a Supemet node.

Implementation Details

Fig. 5 depicts administrative machine 306 and device 302 in greater detail, although the other devices 304 and 308-312 may contain similar components. Device 302 and administrative machine 306 communicate via Internet 314. Each device contains similar components, including a memory 502, 504; secondary storage 506, 508; a central processing unit (CPU) 510, 512; an input device 514, 516; and a video display 518, 520. One skilled in the art will appreciate that these devices may contain additional or different components. Memory 504 of administrative machine 306 includes the SASD process 540, VARPD 548, and KMS 550 all running in user mode. That is, CPU 512 is capable of running in at least two modes: user mode and kernel mode. When CPU 512 executes programs running in user mode, it prevents them from directly manipulating the hardware components, such as video display 518. On the other hand, when CPU 512 executes programs running in kernel mode, it allows them to manipulate the hardware components. Memory 504 also contains a VARPDB 551 and a TCP/IP protocol stack 552 that are executed by CPU 512 running in kernel mode. TCP/IP protocol stack 552 contains a TCP/UDP layer 554 and an IP layer 556, both of which are standard layers well known to those of ordinary skill in the art. Secondary storage 508 contains a configuration file 558 that stores various configuration-related information (described below) for use by SASD 540.

SASD 540 represents a Supemet: there is one instance of an SASD per Supernet, and it both authenticates nodes and authorizes nodes to join the Supernet. VARPD 548 has an associated component, VARPDB 551, into which it stores mappings of the internal Supernet addresses, known as a node IDs, to the network addresses recognized by the public-network infrastmcture, known as the real addresses. The "node ID" may include the following: a Supemet ID (e.g., 0x123), reflecting a unique identifier of the Supemet, and a virtual address, comprising an IP address (e.g., 10.0.0.1). The "real address" is an IP address (e.g., 10.0.0.2) that is globally unique and meaningful to the public-network infrastmcture. In a Supemet, one VARPD runs on each machine, and it may play two roles. First, a VARPD may act as a server by storing all address mappings for a particular Supemet into its associated VARPDB. Second, regardless of its role as a server or not, each VARPD assists in address translation for the nodes on its machine. In this role, the VARPD stores into its associated VARPDB the address mappings for its nodes, and if it needs a mapping that it does not have, it will contact the VARPD that acts as the server for the given Supemet to obtain it.

KMS 550 performs key management by generating a new key every time a node joins a channel and by generating a new key every time a node leaves a channel. There is one KMS per channel in a Supemet.

To configure a Supemet, a system administrator creates a configuration file 558 that is used by SASD 540 when starting or reconfiguring a Supemet. This file may specify: (1) the Supernet name, (2) all of the channels in the Supemet, (3) the nodes that communicate over each channel, (4) the address of the KMS for each channel, (5) the address of the VARPD that acts as the server for the Supernet, (6) the user IDs of the users who are authorized to create Supemet nodes, (7) the authentication mechanism to use for each user of each channel, and (8) the encryption algorithm to use for each channel. Although the configuration information is described as being stored in a configuration file, one skilled in the art will appreciate that this information may be retrieved from other sources, such as databases or interactive configurations.

After the configuration file is created, it is used to start a Supernet. For example, when starting a Supemet, the system administrator first starts SASD, which reads the configuration information stored in the configuration file. Then, the administrator starts the VARPD on the administrator's machine, indicating that it will act as the server for the Supemet and also starts the KMS process. After this processing has completed, the Supernet is ready for nodes to join it.

Memory 502 of device 302 contains SNlogin script 522, SNlogout script 524, VARPD 526, KMC 528, KMD 530, and node A 522, all running in user mode. Memory 502 also includes TCP/IP protocol stack 534 and VARPDB 536 mnning in kernel mode.

SNlogin 522 is a script used for logging into a Supemet. Successfully executing this script results in a Unix shell from which programs (e.g., node A 522) can be started to mn within the Supemet context, such that address translation and security encapsulation is performed transparently for them and all they can typically access is other nodes on the Supemet. Alternatively, a parameter may be passed into SNlogin 522 that indicates a particular process to be automatically run in a Supemet context. Once a program is mnning in a Supernet context, all programs spawned by that program also run in the Supernet context, unless explicitly stated otherwise. SNlogout 524 is a script used for logging out of a Supernet.Although both SNlogin 522 and SNlogout 524 are described as being scripts, one skilled in the art will appreciate that their processing may be performed by another form of software. VARPD 526 performs address translation between node IDs and real addresses. KMC 528 is the key management component for each node that receives updates whenever the key for a channel ("the channel key") changes. There is one KMC per node per channel. KMD 530 receives requests from SNSL 542 of the TCP/IP protocol stack 534 when a packet is received and accesses the appropriate KMC for the destination node to retrieve the appropriate key to decrypt the packet. Node A 532 is a Supernet node running in a Supernet context.

TCP/IP protocol stack 534 contains a standard TCP/UDP layer 538, two standard IP layers (an inner IP layer 540 and an outer IP layer 544), and a Supemet security layer (SNSL) 542, acting as the conduit for all Supernet communications. To conserve memory, both inner IP layer 540 and outer IP layer 544 may share the same instance of the code of an IP layer. SNSL 542 performs security functionality as well as address translation. It also caches the most recently used channel keys for ten seconds. Thus, when a channel key is needed, SNSL 542 checks its cache first, and if it is not found, it requests KMD 530 to contact the appropriate KMC to retrieve the appropriate channel key.

TCP/IP protocol stack 534 is essentially a modified OSI model. Figure 6 depicts the modified OSI model that defines a networking framework for implementing TCP/IP protocol stack 534. A Supernet contains a modification to the network layer in the OSI model. The network layer primarily routes and forwards datagram packets. The network layer is also responsible for receiving incoming datagram packets. Two IP layers 540, 544 are used in the TCP/IP protocol stack 534 because both the internal addressing scheme and the external addressing scheme are IP-based. Thus, for example, inner IP layer 540 processes data 604 passed down from TCP/UDP layer 538 and encapsulates it with its node ID address into header 606. Encapsulation is the inclusion of data within a header so that the data is hidden. Encapsulation typically takes one of two forms: headers and trailers. Headers are prepended to data that has been passed down from upper layers. Trailers are appended to data that has been passed down from upper layers. Also, for example, SNSL layer 542 may encrypt data 610 (the packet received from inner IP layer 540) and encapsulate it into Supernet header 612.

Figure 7 depicts a Supernet packet 700 that has traversed TCP/IP protocol stack 534 described in Fig. 6. Although Fig. 7 depicts a Supernet IP packet, one skilled in the art will appreciate that many different packets may be used instead with a different modified OSI model, such as Appletalk, X.25, or IPX. Supernet packet 700 contains an outer IP header 710, Supernet header 720, Authentication Header (AH) 730, Encapsulating Security Payload (ESP) header 740 and payload data 750. Payload data 750 is a traditional encrypted IP packet 760.

Outer IP header 710 contains a next header field 712, IP source node address 714, and IP destination node address 716. Next header field 712 identifies the type of the next payload after outer IP header 710, such as Supernet header 720. Source real address 714 contains the real address of the originating node of Supernet packet 700. Destination real address 716 contains the real address of the destination node of Supernet packet 700. Supernet header 720 contains a next header field 722 to identify AH 730, key information field 724, and Supemet number field 726. Key information field 724 contains a key used to encrypt ESP header 740 and payload data 750. Supernet number field 726 contains a channel that Supernet packet 700 uses for communication. AH 730 is used to provide authentication services for Supemet packet 700. For example, AH 730 may be a well-known IPSec header. ESP 740 contains virtual source node address 742 and virtual destination node address 744. Virtual addresses 742 and 744 contain the addresses known only to the members of the channel. For example, referring to Fig. 4, if packet 700 were sent from Node A 316 to Node C 320, virtual source node address 742 would correspond to Node A 316, and virtual destination node address 744 would correspond to Node C 320. Finally, payload data 750 contains the original IP packet sent from the source to the destination. One skilled in the art will appreciate that outer IP header 710, Supemet header 720, AH 730, ESP header 740 and payload data 750 may contain additional fields.

Referring back to Figs. 5 and 6, SNSL 542 performs security functionality as well as address translation. It also caches the most recently used channel keys for ten seconds. Thus, when a channel key is needed, SNSL 542 checks its cache first, and if it is not found, it requests KMD 530 to contact the appropriate KMC to retrieve the appropriate channel key.

SNSL 542 utilizes VARPDB 536 to perform address translation. VARPDB stores all of the address mappings encountered thus far by SNSL 542. If SNSL 542 requests a mapping that VARPDB 536 does not have, VARPDB communicates with the VARPD 526 on the local machine to obtain the mapping. VARPD 526 will then contact the VARPD that acts as the server for this particular Supernet to obtain it.

Although aspects of the present invention are described as being stored in memory, 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 a network, such as the Internet; or other forms of RAM or ROM either currently known or later developed. Additionally, although a number of the software components are described as being located on the same machine, one skilled in the art will appreciate that these components may be distributed over a number of machines.

Figs. 8 A and 8B depict a flow chart of the steps performed when a node joins a Supernet. The first step performed is that the user invokes the SNlogin script and enters the Supernet name, their user ID, their password, and a requested virtual address (step 802). Of course, this information depends on the particular authentication mechanism used. Upon receiving this information, the SNlogin script performs a handshaking with SASD to authenticate this information. In this step, the user may request a particular virtual address to be used, or alternatively, the SASD may select one for them. Next, if any of the information in step 802 is not validated by SASD (step 804), processing ends. Otherwise, upon successful authentication, SASD creates an address mapping between a node ID and the real address (step 806). In this step, SASD concatenates the Supemet ID with the virtual address to create the node ID, obtains the real address of the SNlogin script by querying network services in a well-known manner, and then registers this information with the VARPD that acts as the server for this Supemet. This VARPD is identified in the configuration file.

After creating the address mapping, SASD informs the KMS that there is a new Supernet member that has been authenticated and admitted (step 808). In this step, SASD sends the node ID and the real address to KMS who then generates a key ID, a key for use in communicating between the node's KMC and the KMS ("a node key"), and updates the channel key for use in encrypting traffic on this particular channel (step 810). Additionally, KMS sends the key ID and node key to SASD and distributes the channel key to all KMCs on the channel as a new key because a node has just been added to the channel. SASD receives the key ID and the node key from KMS and returns it to SNlogin (step 812). After receiving the key ID and the node key from SASD, SNlogin starts a KMC for this node and transmits to the KMC the node ID, the key ID, the node key, the address of the VARPD that acts as the server for this Supernet, and the address of KMS (step 814). The KMC then registers with the KMD indicating the node it is associated with, and KMC registers with KMS for key updates (step 816). When registering with KMS, KMC provides its address so that it can receive updates to the channel key via the Versakey protocol. The Versakey protocol is described in greater detail in IEEE Journal on Selected Areas in Communication. Vol. 17, No. 9, 1999, pp. 1614-1631. After registration, the KMC will receive key updates whenever a channel key changes on one of the channels that the node communicates over.

Next, SNlogin configures SNSL (step 818 in Fig. 8B). In this step, SNlogin indicates which encryption algorithm to use for this channel and which authentication algorithm to use, both of which are received from the configuration file via SASD. SNSL stores this information in an access control list. In accordance with methods and systems consistent with present invention, any of a number of well-known encryption algorithms may be used, including the Data Encryption Standard (DES), Triple-DES, the International Data Encryption Algorithm (IDEA), and the Advanced Encryption Standard (AES). Also, RC2, RC4, and RC5 from RSA Incorporated may be used as well as Blowfish from Counterpane.com. Additionally, in accordance with methods and systems consistent with the present invention, any of a number of well- known authentication algorithms may be used, including Digital Signatures, Kerberos, Secure Socket Layer (SSL), and MD5, which is described in RFC1321 of the Internet Engineering Task Force, April, 1992.

After configuring SNSL, SNlogin invokes an operating system call, SETVIN, to cause the SNlogin script to run in a Supernet context (step 820). In Unix, each process has a data structure known as the "proc structure" that contains the process ID as well as a pointer to a virtual memory description of this process. In accordance with methods and systems consistent with the present invention, the Supernet IDs indicating the channels over which the process communicates as well as its virtual address for this process are added to this structure. By associating this information with the process, the SNSL layer can enforce that this process runs in a Supernet context. Although methods and systems consistent with the present invention are described as operating in a Unix environment, one skilled in the art will appreciate that such methods and systems can operate in other environments. After the SNlogin script ns in the Supemet context, the SNlogin script spawns a Unix program, such as a Unix shell or a service daemon (step 822). In this step, the SNlogin script spawns a Unix shell from which programs can be run by the user. All of these programs will thus run in the Supemet context until the user mns the SNlogout script.

Fig. 9 depicts a flow chart of the steps performed when sending a packet, such as packet 700 depicted in Fig. 7, from node A. Although the steps of the flow chart are described in a particular order, one skilled in the art will appreciate that these steps may be performed in a different order. Additionally, although the SNSL layer is described as performing both authentication and encryption, this processing is policy driven such that either authentication, encryption, both, or neither may be performed. The first step performed is for inner IP layer 540 to receive a packet originating from node A via the TCP/UDP layer 538 (step 902). The packet contains virtual source node address 742, virtual destination node address 744, and data 754. The packet may be received from a process executing in node A connected to a socket. A socket is a well-known software object that connects an application to a network protocol. In UNIX, for example, an application can send and receive TCP/IP messages by opening a socket and reading and writing data to and from the socket.

Once inner IP layer 542 receives the packet, a Supemet ID is appended to a socket structure (step 904). The socket stmcture is modified so as to contain an extra data field for Supemet ID 726 and virtual source address 742. The addition of Supemet ID 726 and virtual IP address 742 in the socket structure enables the Supernet to communicate with nodes regardless of the infrastructure services used. When the process on node A opens a socket to transmit the packet to inner IP layer 540, the corresponding Supemet ID 726 and virtual source address 742 for that process is included in the socket request.

The packet and Supernet ID are then transmitted to the SNSL layer using the modified socket stmcture (step 906). The SNSL layer then accesses the VARPDB to obtain the address mapping between virtual source node address 742 and the source real address 714 as well as the virtual destination node address 744 and the destination real address 716 (step 908). If they are not contained in the VARPDB because this is the first time a packet has been sent from this node or sent to this destination, the VARPDB accesses the local VARPD to obtain the mapping. When contacted, the VARPD on the local machine contacts the VARPD that acts as the server for the Supemet to obtain the appropriate address mapping. Since the VARPDB maintains all real IP addresses, a remote node may securely communicate with another remote node without reverfication.

After obtaining the address mapping, the SNSL layer determines whether it has been configured to communicate over the appropriate channel for this packet (step 906). This configuration occurs when SNlogin mns, and if the SNSL has not been so configured, processing ends. Otherwise, SNSL obtains the channel key to be used for this channel (step 908). The SNSL maintains a local cache of keys and an indication of the channel to which each key is associated. Each channel key is time stamped to expire in ten seconds, although this time is configurable by the administrator. If there is a key located in the cache for this channel, SNSL obtains the key. Otherwise, SNSL accesses KMD which then locates the appropriate channel key from the appropriate KMC. After obtaining the key, the SNSL layer encrypts the packet using the appropriate encryption algorithm and the key previously obtained (step 910). When encrypting the packet, the virtual source node address 742, the virtual destination node address 744, and the data may be encrypted, but the source and destination real addresses 714, 716 are not, so that the real addresses can be used by the public network infrastructure to send the packet to its destination. That is, Supemet header 720 contains Supemet ID 726 and key information 724, and the packet is encapsulated with the prepended header 710. For example, the packet may be encrypted using the well-known IPSec protocol.

After encrypting the packet, the SNSL layer authenticates the sender to verify that it is the bona fide sender and that the packet was not modified in transit (step 912). In this step, the SNSL layer uses the MD5 authentication protocol, although one skilled in the art will appreciate that other authentication protocols may be used. Next, the SNSL layer passes the packet to outer IP layer 544 where it is then sent to the destination node in accordance with known techniques associated with the IP protocol (step 914).

Fig. 10 depicts a flow chart of the steps performed by the SNSL layer when it receives a packet. Although the steps of the flow chart are described in a particular order, one skilled in the art will appreciate that these steps may be performed in a different order. Additionally, although the SNSL layer is described as performing both authentication and encryption, this processing is policy driven such that either authentication, encryption, both, or neither may be performed. To receive the packet with the additional information, the receiving node contains a modified socket structure similar to the sending node. The first step performed by the SNSL layer is to receive a packet from the network (step 1001). This packet contains a real source address 714 and a real destination address 716 that are not encrypted as well as a virtual source node address 744, a virtual destination node ID 746, and data that are encrypted. Then, it determines whether it has been configured to communicate on this channel to the destination node (step 1002). If SNSL has not been so configured, processing ends. Otherwise, the SNSL layer obtains the appropriate key as previously described from key information 724 (step 1004). It then decrypts the packet using this key and the appropriate encryption algorithm (step 1006). After decrypting the packet, the SNSL layer authenticates the sender and validated the integrity of the packet (step 1008) and then it passes the packet to the inner IP layer for delivery to the appropriate node (step 1010). To pass the additional information to the inner IP layer, the packet is passed using a modified socket structure. Upon receiving the packet, the inner IP layer uses the destination node ID to deliver the packet.

Fig. 11 depicts a flow chart of the steps performed when logging a node out of a Supernet. The first step performed is for the user to mn the SNlogout script and to enter a node ID (step 1102). Next, the SNlogout script requests a log out from SASD (step 1104). Upon receiving this request, SASD removes the mapping for this node from the VARPD that acts as the server for the Supernet (step 1106). SASD then informs KMS to cancel the registration of the node, and KMS terminates this KMC (step 1108). Lastly, KMS generates a new channel key for the channels on which the node was communicating (step 1110) to reduce the likelihood of an intruder being able to intercept traffic.

As an example of an application suitable for methods and systems consistent with the present invention are suitable for use with a Supemet that uses different network infrastructure services. Fig. 12 illustrates a Supernet system 1200 that contains a mobile device using mobile IP and a DHCP client on the same channel of a Supemet. Various hosts 1202 communicate with a mobile device 1210 that uses the mobile IP protocol. Each host may send an encrypted packet to a computer system 1206 as described in Fig. 9. Computer 1202 connects to a computer system 1206 using a network 1204. For example, when an encrypted IP packet is received at computer system 1204, the packet is converted into a mobile IP packet. A control tower 1208, connected to computer system 1206 receives the mobile IP packet and transmits the packet to a mobile device 1210. Mobile device 1210 contains a real address obtained by computer system 1206. Once the real address is obtained, the address together with a corresponding virtual Supemet IP address is forwarded to a VARP server. If the real IP address changes, (e.g., when the mobile device switches computer systems 1206 and is reassigned a new IP address) the mobile IP device forwards the change to the VARP server. The VARP server then notifies all other Supemet clients of the change. Therefore, client 1202 continuously communicates with mobile device 1210 by using the same virtual IP address. The Supemet addressing scheme provides secure communications between host 1202 and mobile device 1210 regardless of the IP address assigned by computer system 1206.

Conclusion

Although the present invention has been described with reference to a preferred embodiment, those skilled in the art will know of various changes in form and detail which may be made without departing from the spirit and scope of the present invention as defined in the appended claims' and their full scope of equivalents.

Claims

WHAT IS CLAIMED IS:

1. A method for transmitting a message from a source that uses at least one infrastructure service to a destination that uses at least one infrastructure service executed in a data processing system, comprising the steps of: receiving an packet from the source that contains a virtual destination address corresponding to the destination; requesting a real address corresponding to the virtual address; encapsulating the packet by prepending a header that contains the real address to the packet; and transmitting the encapsulated packet to the destination associated with the real address.

2. The method of claim 1, wherein the receiving step further includes obtaining the packet from an application in the source.

3. The method of claim 1, wherein the encapsulating step further includes: determining a channel that the packet will use; obtaining a key corresponding to the channel; and encrypting the existing packet to hide the network topology using the key.

4. The method of claim 3 further including the step of: including a channel identifier in the header.

5. The method of claim 1 , wherein the step of: transmitting the encapsulated packet further includes routing the packet on a public network.

6. The method of claim 5 further including the step of: receiving the packet at the destination, wherein the destination and the source are not physically on the same private network.

7. The method of claim 1 , wherein the step of requesting a real address further includes: examining an address table for the corresponding real address; translating the virtual address to a real address based on the address table; and including the virtual address to real address translation in the packet.

8. The method of claim 7 further including the step of: updating the address table to indicate the real address of the destination when the real address changes.

9. The method of claim 1 further including the steps of: receiving the encapsulated packet at the destination; decapsulating the packet by removing the header from the packet.

10. A system for transmitting a message from a source node that uses at least one infrastmcture service to a destination that uses at least one infrastructure service executed in a data processing system, comprising: a destination node; and a source node comprising: a receiving component to receive an packet from a source application running on the source node that contains a virtual address corresponding to the destination application; a requesting component to request a real address that translates to the virtual address; an encapsulating component that encapsulates the packet by prepending a header that contains the real address to the packet; and a transmitting component to transmit the encapsulated packet to the destination node associated with the real address.

11. The system of claim 10, wherein the encapsulating component determines a channel that the packet will use, obtains a key corresponding to the channel, and encrypts the packet to hide the network topology using the key.

12. The system of claim 11, wherein the encapsulating component includes a channel identifier in the header.

13. The system of claim 10, wherein the transmitting component routes the packet on a public network.

14. The system of claim 13, wherein the transmitting component receives the packet at the destination, wherein the destination and the source are not physically on the same private network.

15. The system of claim 10, wherein the requesting component examines an address table for the corresponding real address, translates the virtual address to a real address based on the address table, and includes the virtual address to real address translation in the packet.

16. The system of claim 10, further comprising: an updating component that updates the address table to indicate the real address of the destination.

17. The system of claim 10, wherein the destination node further comprises: a receiving component that receives the encapsulated packet from the source node; a decapsulating component that decapsulates the packet by removing the header from the packet.

18. A method for communicating with a mobile device in a public network, comprising: requesting a real destination address corresponding to a virtual destination address from an address server, wherein the virtual and real destination addresses correspond to the mobile device; encapsulating an packet by prepending a header that contains the real destination address to the packet; and transmitting the encapsulated packet to the mobile device.

19. The method of claim 18, further comprising: assigning the mobile device a new real destination address; and transmitting the new real destination address to the address server when the mobile device is assigned a new real destination address.

20. A method for receiving a secure packet from a host computer on a mobile device through a control tower, wherein the mobile device communicates with the control tower using a mobile infrastructure service, comprising the steps of: receiving the secure packet from the control tower at the mobile device; determining whether the mobile device may communicate with the host computer by querying a channel identification; decapsulating the packet by removing a header from the packet to obtain a real address when it is determined that the mobile device may communicate with the host computer; and translating the real address to a virtual address, wherein the virtual address corresponds to an application running on the mobile device.