Patent Publication Number: US-8995274-B2

Title: Methods and systems for controlling traffic on a communication network

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Applications Nos. 61/08291 filed Jul. 3, 2008, 61/079,411, filed Jul. 9, 2008, 61/110,344, filed Oct. 31, 2008, and 61/156,371, filed Feb. 27, 2009. each of which is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The disclosed subject matter relates to methods and systems for controlling traffic on a communication network. 
     BACKGROUND 
     Attacks on legitimate data flows on communication networks are an ongoing and evolving problem. Denial-of-service, spoofing, and drop attacks are common problems. In a denial-of-service attack, an overwhelming volume of bogus traffic packets and an overwhelming number of requests for a service can be sent to a server to cause the network resource to be overloaded. In a spoofing attack, an attacker pretends to be a legitimate sender and sends data that supplements or replaces a legitimate data flow and thus harms the receiver. In a drop attack, a device on a communication path between a legitimate sender and a legitimate receiver intentionally drop messages and data between the sender and receiver, causing a communication loss. 
     SUMMARY 
     Methods and systems for controlling traffic on a communication network are provided. In accordance with some embodiments, methods for controlling traffic on a communication network are provided, the methods comprising: receiving, at a processor in a receiver, a query message for permission to send a data flow to the receiver; sending a permission message from the receiver; detecting that at least one of a message and a data packet being sent to the receiver has been dropped; and causing the path for sending the data flow to be changed. 
     In accordance with some embodiments, methods for controlling traffic on a communication network are provided, the methods comprising: passing a query message for permission to send a data flow to a receiver; passing a permission message that authorizes the sender to send a given amount of traffic flow; and determining, using a processor, whether data packets are authorized based on the given amount of traffic flow. 
     In accordance with some embodiments, methods for controlling traffic on a communication network are provided, the methods comprising: passing a query message for permission to send a data flow to a receiver; passing a permission message that indicates a security protocol to be used when transmitting packets to the receiver; and detecting, using a processor, that a data packet being sent to the receiver violates the security protocol. 
     In accordance with some embodiments, methods for controlling traffic on a communication network are provided, the methods comprising: receiving, at a processor in a receiver, a query message for permission to send a data flow to the receiver; sending a permission message that indicates a security protocol to be used when transmitting packets to the receiver; and detecting that a data packet being sent to the receiver violates the security protocol. 
     In accordance with some embodiments, systems for controlling traffic on a communication network are provided, the systems comprising a receiver having a processor that: receives a query message for permission to send a data flow to the receiver; sends a permission message from the receiver; detects that at least one of a message and a data packet being sent to the receiver has been dropped; and causes the path for sending the data flow to be changed. 
     In accordance with some embodiments, systems for controlling traffic on a communication network are provided, the systems comprising a receiver having a processor that: passes a query message for permission to send a data flow to a receiver; passes a permission message that authorizes the sender to send a given amount of traffic flow; and determines whether data packets are authorized based on the given amount of traffic flow. 
     In accordance with some embodiments, systems for controlling traffic on a communication network are provided, the systems comprising: a processor that: passes a query message for permission to send a data flow to a receiver; passes a permission message that indicates a security protocol to be used when transmitting packets to the receiver; and detects that a data packet being sent to the receiver violates the security protocol. 
     In accordance with some embodiments, systems for controlling traffic on a communication network are provided, the systems comprising: a receiver having a processor that: receives a query message for permission to send a data flow to the receiver; sends a permission message that indicates a security protocol to be used when transmitting packets to the receiver; and detects that a data packet being sent to the receiver violates the security protocol. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating query and permission messages sent in connection with a data flow between a sender and a receiver in accordance with some embodiments. 
         FIG. 2  is a diagram illustrating detecting of a spoofing attack in accordance with some embodiments. 
         FIG. 3  is a diagram illustrating drop attack that can be detected in accordance with some embodiments. 
         FIG. 4  is a diagram illustrating detecting of a drop attack in accordance with some embodiments. 
         FIG. 5  is a diagram illustrating hardware that can be used in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with various embodiments, mechanisms for controlling traffic on a communication network are provided. These mechanisms can be used in a variety of applications, such as to prevent Denial-of-Service (DoS) attacks and other forms of unauthorized traffic. 
     In some embodiments, the control of traffic on a communication network can be implemented by requiring that permission be granted by a receiver before a sender can send data packets. Additionally, monitoring of data packets and signaling messages can be performed to verify that only authorized data packets are being communicated and that no authorized data packets are being dropped. Data packets that exceed their permission level (if any) can be dropped or rate-limited (e.g., to a very small volume) in some embodiments. 
     In order to control and monitor the transmission of authorized data packets, signaling messages can be sent between various devices on a communication network. For example, a receiver can alert routers (and/or any other suitable devices) between a sender and the receiver that data packets from the sender are authorized to be sent from the sender to the receiver. Permission to send data packets can be configured to automatically expire after a given period of time. However, in some embodiments, the permission can be refreshed periodically to maintain robustness under changing network conditions, such as routing changes, and to insure that permission is maintained for a period of time longer than an expiration duration. 
     To determine whether a flow of data packets violates the given permission for that flow, the volume of the data flow that has been received or sent since the permission state was set up can be determined. This determination can be made at any suitable one or more points along the path between a sender and a receiver. A router or other suitable device on the path can monitor the volume of data flow sent from the sender to the receiver. This data flow monitoring can detect the injection of bogus packets and dropping of legitimate packets. If it is detected that authorized packets are being dropped by a compromised router (or other device), the sender can be triggered to change the data flow path. To change the data flow path, a relay node that is far away from the current path can be used or path diversity by multi-homing can be used in some embodiments. 
     There are at least two message types that can be used to set up permission for a flow of data packets along a path: a query message and a permission message. The query message is sent by the sender to request permission from the receiver. The permission message is sent by the receiver upon granting permission to the sender. Additionally, the permission message can be used to remove (or revoke) and/or modify the permission state for a data flow. 
     In some embodiments, the General Internet Signaling Transport (GIST), described in Schulzrinne and Hancock, “GIST: General Internet Signaling Transport,” Internet Draft “draft-ietf-nsis-ntlp-17,” Internet Engineering Task Force, www.ietf.org, October 2008 (which is hereby incorporated by reference herein in its entirety), can be used to deliver signaling messages along the data path to configure the permission state of routers (or other devices) for a data flow. The GIST can be used to handle all incoming signaling messages and cause them to be passed to the appropriate mechanisms for processing as described herein. The delivery of signaling messages can be handled using a peer-to-peer approach. Thus, each node (or device) that is aware of the mechanism for controlling traffic described herein can forward a signaling message to the next node when it receives the signaling message. 
     In some embodiments, to protect the authentication and integrity of signaling messages, two security mechanisms can be used: message security in an end-to-end fashion and channel security in a hop-by-hop fashion. Message security can be used to protect the integrity of the messages on end-to-end traffic and channel security can be used to protect the integrity and confidentiality of the messages between adjacent nodes. The message security (which can be implemented using public key cryptography in some embodiments) is used to protect messages from being modified by attackers. The channel security (which can be implemented using transport layer security (TLS) and/or datagram transport layer security (DTLS) in some embodiments) can be used to distribute a shared key for Internet Protocol Security (IPsec) of data packets to the routers along the data path in a hop-by-hop fashion. 
     To authenticate data packets, a sender can use any suitable security protocol, such as IPsec Authentication Header (AH) (which is described in RFC4302 of the Internet Engineering Task Force (which is hereby incorporated by reference herein in its entirety)) for example. As another example, IPsec Encapsulating Security Payload (ESP) (which is described in RFC4303 of the Internet Engineering Task Force (which is hereby incorporated by reference herein in its entirety)) can be used for authentication in some embodiments. When using such a security protocol, routers can be configured to drop bogus packets, which may have been inserted by an unauthorized source, using an IP packet filter. When using IPsec AH, any suitable security mechanism can be used to protect the integrity of the authentication data field. For example, in a Byzantine network (e.g., one in which the sender and/or the routers are not trusted), a public key cryptography algorithm, such as RSA and Elliptic curve cryptography (ECC), can be used for the authentication data field in IPsec AH. As another example, in a trustworthy network (e.g., one in which routers are trusted and are not compromised), a symmetric key cryptography algorithm, such as Keyed-Hashing for Message Authentication (HMAC) (which is described in RFC2104 (which is hereby incorporated by reference herein in its entirety)), can be used for the authentication data field in IPsec AH because there are no on-path attackers in the trustworthy network. A receiver can choose a cryptography algorithm for the data message based on the policy, network, and applications used in some embodiments. The sequence number in the IPsec can also be used to detect bogus packets that are injected into the network. 
     Turning to  FIG. 1 , an example  100  of how permissions can be set up between a sender  102  and a receiver  108  in accordance with some embodiments is illustrated. As shown, a sender  102  sends a receiver  108  a query message  110  to request permission to send a data flow  122 . The requested application is described in a flow identifier of the query message. The query message installs the reverse routing state in GIST for the path of a permission message  116 . Receiver  108  then sends sender  102  permission message  116  to allow incoming data packets in a data flow  122  along the path of query message  110 . After the permission state is set up between the sender and the receiver, the sender can then send the allowed volume (permission) of data to the receiver during the time interval specified. 
     Sender  102  can send a query message  110  and  124  every refresh period (T)  136  in some embodiments. Receiver  108  can then send sender  102  a permission message  116  or  118  after receiving a query message  110  or  124 . 
     In some embodiments, asymmetric transmission of query and permission messages can be supported. After a permission state is set up, if the receiver wants to change the permission state or security algorithm, it can send another permission message without receiving another query message. 
     A public key encryption algorithm can be used in some embodiments to protect fields (described below) in the signaling messages. This encryption can be used to support the authentication and integrity of the messages. To bind a public key and the sender, an X.509 certificate (which is described in RFC5280 (which is hereby incorporated by reference herein in its entirety)) can be used, and the certificate can be carried in the signaling messages in some embodiments. Alternatively, Cryptographically Generated Addresses (CGA) (which is described in RFC3972 (which is hereby incorporated by reference herein in its entirety)) can be used with Internet Protocol version 6 (IPv6) to bind an IPv6 address and a public key, instead of a public key certificate, in some embodiments. 
     In some embodiments, a proof-of-work mechanism can be used to rate-limit query messages that might be maliciously used to mount a denial-of-service attack. For example, a proof-of-work mechanism may require a sender to perform some time- or processing-power-intensive task (such as repeated performance of a hash function) that is then verified by a receiver before a query message will be accepted. 
       FIG. 2  shows an example of detecting an attack in accordance with some embodiments. As illustrated, two signaling messages (query message  210  and permission message  212 ) set up a permission state for a data flow  214  between a sender  202  and a receiver  208 . In this example, assume that receiver  208  grants a 10 MB size permission to sender  202  and asks the sender to use symmetric key cryptography to encrypt the authentication field of IPsec. After setting up the permission state, sender  202  sends data packets whose total volume is 1 MB. Next, an attacker  216 , which spoofs the address of sender  202  and has the shared key, sends additional attack packets  218  whose total volume is 2 MB. After a refresh period (T)  220 , sender  202  sends a query message  222  that contains an indication of the volume of data (in this example, 1 MB) that it has sent. Because query message  222  is protected by public key cryptography, others cannot generate and/or modify the query message. Receiver  208  can then detect the attack by comparing the indication of the volume in the query message (in this example, 1 MB) and total volume of data (in this example, 3 MB) that the receiver has received. After receiver  208  detects the attack, it sends a permission message  226  with an indication to change the cryptography algorithm of IPsec AH to public key cryptography, such as RSA and ECC, to defeat the attacker&#39;s knowledge of the symmetric key. After sender  202  receives permission message  226 , the sender changes the cryptography algorithm for the IPsec AH of data packets. Subsequent attack packets using the outdated symmetric key will then be dropped at one of devices  204  or  206  because of the new IPsec AH verification process. 
     In some embodiments, drop attacks (or black-hole attacks) can be detected. In an example of such an attack, a compromised router between a sender and a receiver drops all packets and/or messages or drops selected packets.  FIG. 3  illustrates an example  300  of detecting a drop attack. As shown, an attacker  306  drops all packets and signaling messages being transmitted from a sender  302  to a receiver  308 . Because sender  302  does not receive a permission message after sending two query messages  310  and  312  and waiting for timeouts  314  and  316  to expire, it suspects that the packets might have been dropped. Therefore, it changes the path of the messages and data flow at point  318 . 
     In  FIG. 4 , another example  400  of detecting a drop attack is shown. As illustrated, an attacker  406  drops data packets  410  but forwards signaling messages  412 ,  414 ,  416 , and  418 . A query message  416  indicates the volume of data (in this example, 1 MB) that sender  402  has sent to receiver  408 . Since receiver  408  has not received the data flow  410 , the receiver can detect the packet drop attack. Receiver  408  then sends a permission message  418  indicating a request to change the path of the data flow and signaling messages to avoid attacker  406 . After receiving the permission message, sender  402  changes the path. 
     Signaling messages (such as query messages and permission messages), in some embodiments, can include a common header and one or more type-length-value (TVA) objects. The common header can indicate the message type of the message. For example, the header can indicate whether the message is a query message or a permission message. As described above, query messages can be used to request permission and monitor traffic flow. A query message can include a common header, a flow identification, a message sequence number, a requested volume, a sent volume, a public key certificate, and authentication data. As also described above, a permission message can be used to set up, remove, and modify a permission state for a flow. A permission message can include a common header, a flow identification, a message sequence number, an allowed volume, a time-to-live (TTL), a refresh time, a public key certificate, a defense, and authentication data. 
     In some embodiments, objects begin with the common object header. The header can indicate an object&#39;s type and the length of the object. Some examples of the object type are flow identification, message sequence number, and allowed volume. The header can also indicate how to treat the objects when they are unknown. For example, the indication can be “Mandatory” (e.g., if the object is not understood, the entire message containing it must be rejected, and an error message sent back), “Ignore” (e.g., if the object is not understood, it must be deleted and the rest of the message processed as usual), “Forward” (e.g., if the object is not understood, it must be retained unchanged in any message forwarded as a result of message processing, but not stored locally), etc. 
     The flow identification can indicate an IP address version (e.g., version 4, 6, etc.), a protocol identifier, the port number of the sender, the port number of the intended receiver, the IP address of the sender, and the IP address of the intended receiver. 
     The message sequence number can include an incrementing sequence number. This can be used to prevent a replay attack. 
     The requested volume can indicate the number of bytes that a sender requests for a data flow. 
     The sent volume can indicate the number of bytes that a sender has sent since the sender received the permission. 
     The allowed volume can indicate the number of bytes that a receiver allows for a flow. 
     The time-to-live (TTL) can indicate the time limit for the permission state of a flow. This TTL can be expressed in units of time (e.g., milliseconds, etc.) in some embodiments. 
     The refresh time can indicate the period of time during which the permission remains valid. 
     The public key certificate can include an X.509 certificate (or any other suitable certificate) of a node&#39;s public key. 
     The defense indicator can indicate a solution against an attack. For example, the defense indicator can indicate that no action is to be taken, that symmetric key cryptography is to be used to encrypt the authentication field of IPsec, that public key cryptography is to be used to encrypt the authentication field of IPsec, that the path is to be changed to avoid a compromised router, etc. The defense indicator can also indicate an IPsec authentication algorithm—e.g., the cryptography algorithm for the IPsec authentication field. For example, this can be HMAC-SHA1, HMAC-SHA-256, HMAC-MD5, RSA-1024, RSA-2048, ECC-160, ECC-224, Digital Signature Algorithm (DSA)-1024. DSA-2048, or the algorithm from an X.509 certificate. The defense indicator can further include the key for the IPsec authentication field. 
     The authentication data can indicate the encrypted data of message fields for authentication and integrity. A public key encryption technique can be used for encrypting the message field data. 
     Turning to  FIG. 5 , an example  500  of hardware for implementing methods and systems for controlling traffic on a communication network is illustrated. As shown, this hardware can include a sender  502 , a receiver  508 , a communication network  503 , routers  504 ,  505 ,  506 ,  510 ,  511 ,  512 , and  516 , and connections  520  and  522 . Sender  502  can be any suitable device that sends data to receiver  508 . For example, sender  502  can be a general purpose device such as a computer or a special purpose device such as a client, a server, a Voice over Internet Protocol (VoIP) telephone, a multimedia device, etc. Receiver  508  can be any suitable device that receives data from sender  502 . For example, receiver  508  can be a general purpose device such as a computer or a special purpose device such as a client, a server, a Voice over Internet Protocol (VoIP) gateway or multi-conferencing unit, a multimedia server, etc. Any of these general or special purpose devices can include any suitable components such as a processor (which can be a microprocessor, digital signal processor, a controller, etc.), memory, communication interfaces, display controllers, input devices, etc. Communication network  503  can be any suitable communication network, such as the Internet, a local area network (LAN), a wide area network (WAN), a wired network, a wireless network, a telephone network, a cable television network, a satellite network, etc. Routers  504 ,  505 ,  506 ,  510 ,  511 ,  512 , and  516  can be any suitable devices that can pass data being transmitted between sender  502  and receiver  508 . For example, any one or more of routers  504 ,  505 ,  506 ,  510 ,  511 ,  512 , and  516  can be a router, a gateway, a switch, a firewall, or any other suitable device. Connections  520  and  522  can be any suitable connections for connecting sender  502  and receiver  508  to communications network  503 . For example, connections  520  and  522  can be wired or wireless connections. 
     Although the invention has been described and illustrated in the foregoing illustrative embodiments, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the invention can be made without departing from the spirit and scope of the invention, which is only limited by the claims which follow. Features of the disclosed embodiments can be combined and rearranged in various ways.