Firewall-tolerant voice-over-internet-protocol (VoIP) emulating SSL or HTTP sessions embedding voice data in cookies

• US 7,206,932 B1
• Filed: 02/14/2003
• Issued: 04/17/2007
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: CrystalVoice Communications, Inc. (Alphabet Inc.)
• Inventors: Kirchhoff, Debra C.
• Primary Examiner(s): Barron; Gilberto
• Assistant Examiner(s): SZYMANSKI, THOMAS M
• Application Number:
  US10/248,762
• Time in Patent Office: 1,523 Days
• Field of Search: 726/11, 726/13, 713/152
• US Class Current: 713/152
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 63/166 at the transport layer
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 9/0838 Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these network architectures or network communication protocols for key exchange in a packet data network H04L63/061

Abstract

A voice-over-Internet-Protocol (VoIP) client codes audio data as printable ASCII characters, then embeds the ASCII audio data inside a cookie that is sent over the Internet within an HTTP GET message. The GET message is sent to a server acting as a call proxy or external manager that forwards the audio data to a remote client. Return audio data is sent back to the client in the normal data field of an HTTP response message from the server. When the client receives the HTTP response, it sends another GET message without audio data, allowing the server to send another response. This empty GET allows VoIP to pass through strict firewalls that pair each HTTP response with a GET. For secure-sockets layer (SSL), client and server exchange pseudo-keys in hello and finished messages that establish the SSL session. Audio data is streamed in SSL messages instead of encrypted data.

Claims

1. A firewall-tolerant Voice-over-Internet-Protocol (VoIP) system comprising:

a VoIP client that receives local audio captured from a local user, and plays back remote audio from a remote user, the VoIP client comprising;

a sending thread that receives the local audio and generates a hyper-text transfer protocol HTTP GET message that contains an audio cookie, the local audio being embedded in the audio cookie for transport over an Internet;

wherein the audio cookie is an HTTP cookie field specified by an HTTP protocol to contain user data that is generated by a server and stored on a client, but specified to be sent to the server when the client later re-connects with the server;

wherein the HTTP GET message is a message specified to be used to request data from a server;

a receiving thread that receives an HTTP response message from a server on the Internet, the HTTP response message containing a data field that contains the remote audio from the remote user, the receiving thread reading the data field to extract the remote audio for playback to the local user;

whereby local audio is transported to the server in the audio cookie that uses the HTTP cookie field specified to be used for transferring user data generated by the server.

2. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 1 wherein the VoIP client further comprises:

a format converter, receiving the local audio in a binary format, that converts the local audio into an American Standard Code for Information Interchange (ASCII) format for transport by the audio cookie,

whereby the audio cookie contains local audio converted to the ASCII format.

3. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 2 wherein the remote audio in the data field of the HTTP response message is in the binary format;

wherein the format converter expands the local audio in the binary format to generate local audio in the ASCII format,

whereby the binary format is more compressed than the ASCII format.

4. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 3 wherein the local audio is converted to a restricted range of values, the restricted range of values being values for printable ASCII characters that excludes values for non-printable ASCII control characters,

whereby the local audio is converted to printable ASCII characters for transport in the audio cookie.

5. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 2 wherein the receiving thread further sends to the server an empty HTTP GET message that contains no audio data in response to receiving the HTTP response message, the empty HTTP GET message for allowing another HTTP response message from the server to pass through an intervening firewall when the sending thread is not sending the HTTP GET message with the audio cookie, whereby the empty HTTP GET message allows further HTTP response messages to pass through the intervening firewall.

6. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 5 further comprising:

a VoIP server application, running on the server, that comprises;

a server receiving thread, coupled to receive the HTTP GET message from the client, the server receiving thread extracting the local audio from the audio cookie and forwarding the local audio to a remote client;

a server sending thread, receiving the remote audio from the remote client, the server sending thread generating and transmitting the HTTP response message to the client by embedding the remote audio in the data field of the HTTP response message.

7. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 6 wherein the server is a voice-proxy server that is separate from the remote client, the VoIP server application forwarding audio among VoIP clients.

8. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 7 wherein the server receiving thread also receives an empty HTTP GET message from the client, the server receiving thread discarding the empty HTTP GET message,

wherein the empty HTTP GET message contains no audio data in response to receiving the HTTP response message, the empty HTTP GET message for allowing another HTTP response message from the server to pass through an intervening firewall when the sending thread is not sending the HTTP GET message with the audio cookie,

whereby the empty HTTP GET message is discarded by the server.

9. The firewall-tolerant Voice-over-Internet-Protocol (VoIP) system of claim 5 wherein the local audio and the remote audio are captured voice that is compressed and encoded using a voice codec.

10. A computer-implemented method for making a voice call over an Internet comprising:

generating a hyper-text transfer protocol (HTTP) GET message that contains an audio cookie;

placing audio data from a local user inside the audio cookie;

sending the HTTP GET message with the audio cookie from a client to a server, the server extracting the audio data from the audio cookie for playback to a remote user;

receiving an HTTP response message from the server;

extracting remote audio data from a data field in the HTTP response message, the remote audio data containing audio from the remote user for playback to the local user;

sending an empty GET message from the client to the server when the HTTP response message is received, the empty GET message being an HTTP GET message without a cookie,

whereby audio data is placed in the audio cookie.

11. The computer-implemented method of claim 10 further comprising:

capturing voice from the local user;

encoding captured voice to generate the audio data placed in the audio cookie, wherein the audio data contains encoded voice captured from the local user.

12. The computer-implemented method of claim 11 further comprising:

converting audio data from a binary format to a character format to generate the audio data placed inside the audio cookie;

receiving the remote audio data in the binary format from the data field in the HTTP response message,

whereby the remote audio data is in the binary format but the audio data is converted to the character format for transmission inside the audio cookie.

13. The computer-implemented method of claim 10 further comprising:

wherein placing audio data from a local user inside the audio cookie comprises placing the audio data in an HTTP cookie field, the HTTP cookie field being specified by an HTTP protocol to contain user data that is generated by a server and stored on the client, but sent to the server when the client later re-connects with the server,

whereby the audio cookie contains client-generated audio data but uses the HTTP cookie field specified to be used for transferring user data generated by the server.

14. A computer-program product comprising:

a computer-usable medium having computer-readable code means embodied therein for communicating audio data from a client to a server through a firewall, the computer-readable program code means in the computer-program product further comprising;

hyper-text transfer protocol (HTTP) means for opening an HTTP window in the firewall, the HTTP means comprising;

cookie means, receiving a client audio stream, for placing the audio data from the client inside a cookie;

GET means, receiving the cookie from the cookie means, for generating a GET message that contains the cookie, the GET message being sent to the server using one or more of TCP packets;

wherein the audio data is sent to the server inside the cookie;

response means, receiving a remote audio stream for playback to the client, for receiving from the server remote audio data in the remote audio stream, a remote audio streaming means extracting the remote audio data from a server-data field in HTTP response messages sent by the server to the client, the HTTP response messages carrying the remote audio data in the server-data field; and

empty GET means for sending an empty GET message to the server when the HTTP response message is received but the GET message with the cookie is not generated;

wherein the HTTP response messages are paired with the empty GET message or the GET message with the cookie, whereby the remote audio data is received from the server in the server-data field but the audio data is sent to the server inside the cookie.

15. The computer-program product of claim 14 wherein the computer-readable program code means in the computer-program product further comprises:

converter means, coupled to the cookie means, for converting binary audio data into printable-character audio data, the printable-character audio data being the audio data inside the cookie;

wherein the printable-character audio data mimics printable characters, whereby the cookie contains converted audio data that mimics printable characters.