Network protocol reassembly accelaration

Abstract

Methods and systems are provided for network protocol reassembly acceleration. According to one embodiment, an incoming packet is received at a network interface. Payload data from the packet is written by a memory interface to a physical page within a system memory on behalf of the network interface based on a sequence number associated with the incoming packet and by obtaining a physical address from a virtual memory map corresponding to an incoming session with which the packet is associated. After the physical page is full, the physical page is made accessible to a user process being executed by a processor associated with the system memory by remapping the physical page through a paging table used by the user process.

1 . A method comprising:
 receiving an incoming packet at a network interface;   a memory interface writing payload data from the packet to a physical page within a system memory on behalf of the network interface based on a sequence number associated with the incoming packet and by obtaining a physical address from a virtual memory map corresponding to an incoming session with which the packet is associated; and   after the physical page is full, making the physical page accessible to a user process being executed by a processor associated with the system memory by remapping the physical page through a paging table used by the user process.   
   
   
       2 . The method of  claim 1 , wherein the incoming packet comprises a TCP packet and the incoming session comprises an incoming TCP session. 
   
   
       3 . The method of  claim 2 , further comprising a network interface driver being executed by the processor allocating one or more physical pages of the system memory for each of a plurality of incoming TCP sessions, including the incoming TCP session. 
   
   
       4 . The method of  claim 3 , further comprising the network interface driver building virtual memory maps, including the virtual memory map, corresponding to the plurality of incoming TCP sessions. 
   
   
       5 . The method of  claim 4 , further comprising the network interface driver building a session table including information regarding a page directory base address for each of the plurality of incoming TCP sessions and information regarding an offset to adjust a start address of the payload data with respect to a boundary of the physical page. 
   
   
       6 . The method of  claim 5 , further comprising:
 calculating an adjusted sequence number based on the sequence number and the offset; and   using the adjusted sequence number as a virtual address input to the virtual memory map.   
   
   
       7 . The method of  claim 2 , further comprising, prior to the memory interface writing payload data from the TCP packet to the physical page, determining whether the physical page has been allocated. 
   
   
       8 . A network device comprising:
 a processor configured to execute one or more user processes and a network interface driver;   a system memory, coupled to the processor, having stored therein (i) a paging table used by the processor to translate virtual memory addresses into corresponding physical memory addresses and (ii) a plurality of virtual memory maps containing information for use in connection with translating a virtual address input based on a sequence number of an incoming Transmission Control Protocol (TCP) packet to a physical address;   a network interface operable to receive incoming TCP packets;   an interconnect bus coupled to the processor and the system memory; and   a bus/memory interface, coupled to the network interface and the interconnect bus, adapted to write payload data from the incoming TCP packet to a physical page within the system memory on behalf of the network interface based on the sequence number and a virtual memory map of the plurality of virtual memory maps corresponding to an incoming TCP session with which the TCP packet is associated; and   wherein the network interface driver makes the physical page accessible to a user process of the one or more user processes by remapping the physical page through the paging table.   
   
   
       9 . The network device of  claim 8 , wherein the network interface driver is further configured to allocate one or more physical pages of the system memory for each of the plurality of incoming TCP sessions. 
   
   
       10 . The network device of  claim 9 , wherein the network interface driver is further configured to create and maintain the plurality of virtual memory maps. 
   
   
       11 . The network device of  claim 10 , wherein the network interface driver is further configured to build a session table within the system memory including information regarding a page directory base address for each of the plurality of incoming TCP sessions and information regarding an offset to adjust a start address of the payload data with respect to a boundary of the physical page. 
   
   
       12 . The network device of  claim 11 , wherein the virtual address is determined by calculating an adjusted sequence number based on the sequence number and the offset. 
   
   
       13 . The network device of  claim 8 , wherein the network device comprises a network security platform. 
   
   
       14 . The network device of  claim 8 , wherein the user process performs one or more security functions. 
   
   
       15 . The network device of  claim 14 , wherein the one or more security functions include one or more of antivirus scanning, spam detection, web filtering, firewalling, intrusion detection, intrusion prevention and virtual private network (VPN) services. 
   
   
       16 . A program storage device readable by one or more processors of a network device, tangibly embodying a program of instructions executable by the one or more processors to perform method steps for performing Transmission Control Protocol (TCP) reassembly, the method comprising:
 receiving an incoming TCP packet at a network interface of the network device;   writing payload data from the TCP packet to a physical page within a system memory based on a sequence number associated with the incoming TCP packet and by obtaining a physical address from a virtual memory map corresponding to an incoming TCP session with which the TCP packet is associated; and   after the physical page is full, making the physical page accessible to a user process being executed by a processor associated with the system memory by remapping the physical page through a paging table used by the processor.   
   
   
       17 . The program storage device of  claim 16 , wherein the user process performs one or more security functions. 
   
   
       18 . The program storage device of  claim 17 , wherein the one or more security functions include one or more of antivirus scanning, spam detection, web filtering, firewalling, intrusion detection, intrusion prevention and virtual private network (VPN) services.