Processing data for a TCP connection using an offload unit

A system for processing data for a delegated TCP connection, comprising:

• a TCP stack configured to process received frames stored in at least one legacy buffer;
• a software driver configured to interface between the TCP stack and an off load unit;
• a memory configured to store user buffers in a first portion that is allocated to an application program and to store legacy buffers in a second portion that is allocated to the software driver, wherein each user buffer is configured to store processed frame data for the delegated TCP connection;
• and
• the off load unit configured to:
• receive user buffer descriptors specifying locations of the user buffers;
• indicate in a field of the user buffer descriptor how many of the user buffers are accepted to store payload data for the delegated TCP connection before the processed frame data is stored in one of the user buffers;
• process frames received on the delegated TCP connection to produce payload data and partially processed frames;
• upload partially processed frames to at least one of the legacy buffers;
• and
• upload the payload data to at least one of the user buffers.

A method of processing frames for delegated and non-delegated TCP connections, comprising:

• receiving user buffer descriptors that specify locations of a plurality of user buffers in a first portion of memory that is allocated to an application program, wherein each user buffer is configured to store processed frame data for the delegated TCP connections;
• processing delegated TCP connections using an offload unit, the off load unit configured to process frames for which special cases do not exist to produce processed frame data;
• indicating in a field of a user buffer descriptor how many of the user buffers are accepted to store processed frame data for each one of the delegated TCP connections before the processed frame data is stored in one of the user buffers;
• uploading the processed frame data to a user buffer in a first portion of memory that is allocated to an application program;
• processing non-delegated TCP connections using a TCP stack executing on a CPU;
• uploading frame data for the non-delegated TCP connections to a legacy buffer in a second portion of the memory that is allocated to a software driver configured to communicate between the offload unit and the TCP stack;
• and
• processing all frames for which special cases exist using the TCP stack executing on the CPU.