CN102546394B - TCP (Transmission Control Protocol) connection elimination method - Google Patents

Abstract

The invention provides a TCP (Transmission Control Protocol) connection elimination method, which is characterized in that: least recently used (LRU) TCP connection which has the smallest access frequency is eliminated all the time by using high-efficiency storage and retrieval of hash and an effective TCP connection elimination mechanism. Compared with the prior art, the TCP connection elimination method has the beneficial effects that: one TCP connection elimination strategy is realized; holding of an active node with more frequent access is guaranteed; and the node with low access frequency which is not accessed at the longest is eliminated. According to the method, the active connection is held, and synflood attack can be prevented to a certain extent.

Description

A kind of TCP connects the method for eliminating

Technical field

The invention belongs to network safety filed.Be specifically related to a kind of TCP and connect the method for eliminating.

Background technology

Along with the develop rapidly of network, network environment becomes increasingly complex, and the data transmitted in a network are more difficult to ensure its original order of card, in order to effectively analyze upper layer application, ensure the speed of data flow on response backbone network, TCP Unloading Technology is day by day universal simultaneously.Due to the restriction of system resource, as: physical memory etc.The TCP concurrent connection number supported is also limited, under network environment at a high speed, certainly exists larger TCP concurrent connection number, also just there is the superseded problem that TCP connects.Eliminating that TCP connects mainly comprises two steps, the replacement policy that TCP connects and retrieval.Wherein retrieval occupies main time complexity, and traditional method stores the order that TCP connects according to setting up, and travels through during retrieval to all-links.When concurrent connection is larger, ordered retrieval efficiency is very low, and time complexity is read as O (n), n are the length of the concurrent connection of TCP.Therefore, in order to raise the efficiency, the system that concurrent connection number is larger, the general hash chained list that adopts stores, and each hash item connects a conflict chain, can adopt hash method when retrieving, and time complexity is conflict chain length.At this mechanism row.Replacement policy generally uses untapped superseded method at most.

Patent No. CN200580011566.3 (providing agreement to realize the method and apparatus of the wireless tcp session using split-type TCP to connect) discloses a kind of method and system, and this system operates in order to set up TCP session via wireless network and internet between MS and end points destination according to the method.The method comprises split-type TCP connection request is sent to from this MS the PEP being arranged in this network, and wherein this split-type TCP connection request comprises the information for identifying the network address of this MS and the network address of this end points destination.The method also comprises in response to receiving this split-type TCP connection request from this MS, set up split-type TCP to connect, this split-type TCP connects the wireless tcp (WTCP) be included between this MS with this PEP and to be connected and TCP at least part of way between this PEP with this end points destination is connected.In one embodiment, this end points destination is the application server being coupled to internet, and this TCP is connected between this PEP and this application server and sets up.In another embodiment, this end points destination is the 2nd MS being coupled to the 2nd PEP in second wireless network, and this TCP connection is at least established to the 2nd PEP, is then that WTCP connects from the 2nd PEP to the 2nd MS.

Patent No. CN200610066008.3 (a kind of merging method that TCP connects) discloses a kind of merging method that TCP connects, its feature comprises: A, first, second to send respectively to main equipment from equipment and set up TCP connection request, main equipment adopts mode of cheating to send acknowledge message immediately to first, second from equipment, under main equipment does not start TCP handling process situation, first, second is set up TCP respectively from equipment and is connected TCP I, TCP II with main equipment; B, set up the corresponding relation that these two TCP connect TCP I, TCP II on the master; C, first, second from equipment by main equipment forward carry out transfer of data.Adopt the merging method that TCP of the present invention connects, because intermediate node need not process complicated Transmission Control Protocol and state machine, greatly reduce the processing load of intermediate node.Network processing unit or hardware logic can be adopted to realize high speed forward, the merging that more than two TCP are connected thus are realized transmitting end to end.

The shortcoming of prior art is: adopt the method do not used at most to eliminate TCP and connect, likely eliminate leading portion very active, but the connection do not arrived every a period of time due to network reason data.Simultaneously when synflood attacks, be easy to effective TCP to connect eliminate.

Summary of the invention

The present invention overcomes prior art deficiency, and the replacement policy connected by adjustment TCP, is ensured that live-vertex is kept, delete minimum, the connected node do not used at most, can prevent synflood from attacking to a certain extent.

The invention provides a kind of TCP and connect the method for eliminating, by using hash store efficiently and retrieve, setting up effective TCP and connecting eliminative mechanism, superseded access times are minimum all the time, and the TCP do not used at most connects.

TCP provided by the invention connects the method for eliminating, and comprises the steps:

1) the concurrent connection table of initialization;

2) receive syn, reset packet, search concurrent chained list according to four-tuple, go to step 5;

3) receive syn ack or ack packet, go to step 8;

4) receive fin or fin ack packet, go to step 9;

5) search successfully, then the syn bag for retransmitting, abandons; Search unsuccessfully, then check whether maximum concurrent connection number is greater than threshold value, is less than, and goes to step 6, otherwise go to step 7.

6) search call number minimum, the connected node of no access is at most eliminated;

7) newly-built concurrent connection item, call number puts 1, is the node head of 1, goes to step 10 node motion to call number;

8) search node, success, then increase call number, and node motion is first to identical call number node, and failed then disconnected data then abandon; Go to step 10;

9) corresponding connection is closed.

One of 10) processing data packets terminates, and next packet arrives and goes to step 2,3,4.

Compared with prior art, beneficial effect of the present invention is: this TCP of the present invention connects replacement policy, and guarantee access ratio more frequently live-vertex is kept, and superseded access times are few, and the node of not accessing at most.The method can prevent synflood from attacking to a certain extent.

accompanying drawing explanation

Fig. 1 is the flow chart that a kind of TCP connects the method for eliminating.

embodiment

The detailed step of the present invention program is as follows:

1. the concurrent connection table of initialization;

2. receive syn, reset packet, search concurrent chained list according to four-tuple, go to step 5;

3. receive syn ack or ack packet, go to step 8

4. receive fin or fin ack packet, go to step 9;

5. search successfully, then the syn bag for retransmitting, abandons; Search unsuccessfully, then check whether maximum concurrent connection number is greater than threshold value, is less than, and goes to step 6, otherwise go to step 7.

6. search call number minimum, the connected node of no access is at most eliminated;

7. newly-built concurrent connection item, call number puts 1, is the node head of 1, goes to step 10 node motion to call number

8. search node, success, then increase call number, and node motion is first to identical call number node, and failed then disconnected data then abandon; Go to step 10;

9. close corresponding connection.

10. until system closing, otherwise go to step 2.

Above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment to invention has been detailed description, the those of ordinary skill in described field is to be understood that: still can modify to the specific embodiment of the present invention or replace on an equal basis, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.

Claims (1)

1. TCP connects the method for eliminating, and it is characterized in that, by using hash store efficiently and retrieve, setting up effective TCP and connecting eliminative mechanism, superseded access times are minimum all the time, and the TCP do not used at most connects;

1) the concurrent connection table of initialization;

2) receive syn, reset packet, search concurrent chained list according to four-tuple, go to step 5;

3) receive syn ack or ack packet, go to step 8;

4) receive fin or fin ack packet, go to step 9;

5) search successfully, then the syn bag for retransmitting, abandons; Search unsuccessfully, then check whether maximum concurrent connection number is greater than threshold value, is less than, and goes to step 7, otherwise go to step 6;

6) search call number minimum, the connected node of no access is at most eliminated;

7) newly-built concurrent connection item, call number puts 1, is the node head of 1, goes to step 10 node motion to call number;

8) search node, success, then increase call number, and node motion is first to identical call number node, and failed then disconnected data then abandon; Go to step 10;

9) corresponding connection is closed;

One of 10) processing data packets terminates, and next packet arrives and goes to step 2,3,4.