CN1323352C - A Method of Realizing Dynamic Host Configuration Protocol Server Startup and Update Based on VxWorks Operating System - Google Patents

Abstract

The present invention relates to a method for realizing the startup and update of a dynamic host configuration protocol server on the basis of a VxWorks operating system. The present invention has the improvement that firstly, the startup method of the DHCP server is modified to make the DHCP server independent of a VxWorks kernel, and a startup opportunity is controlled by an application program; secondly, address records are simultaneously and permanently stored by a database method, and the dynamic update of the content in a memory address pool is realized. The present invention has the effect that the present invention solves the problems of inconvenient startup, incomplete refresh address recording function, etc. in the VxWorks with the DHCPS server. The present invention makes the DHCPS server independent of the VxWorks kernel, permanently stores the addresses records by a database, and dynamically updates the content in the memory address pool. Thus, the DHCPS server is easy to maintain and manage.

Description

A Method of Realizing Dynamic Host Configuration Protocol Server Startup and Update Based on VxWorks Operating System

technical field

The present invention relates to a method for starting and updating a dynamic host configuration protocol server based on a VxWorks operating system, specifically a method for implementing a dynamic host configuration protocol server based on a VxWorks operating system and dynamically updating a memory address pool by an application program, especially It is suitable for network systems of diskless workstations that need to bootstrap through Dynamic Host Configuration Protocol (DHCP).

Background technique

The VxWorks operating system is an embedded real-time operating system launched by the American WindRiver company in the 1980s. In recent years, the VxWorks real-time operating system has been widely used, and it is one of the commonly used embedded operating systems in communication systems. The VxWorks operating system supports the TCP/IP network protocol stack, and the user can easily implement many application protocols by calling interface functions. These protocols are embedded in the VxWorks operating system kernel, and the codes cannot be modified.

Dynamic Host Configuration Protocol (DHCP) is one of the application layer protocols supported by VxWorks operating system. The DHCP protocol adopts the client/server (Client/Server) method and consists of two parts: DHCP Server and DHCP Client. After the DHCP Client is started, it does not have its own IP address and needs to apply for an IP address from the DHCP Server through protocol interaction. DHCP Server assigns IP addresses to requesting clients according to certain rules.

The VxWorks operating system provides hook functions for DHCP Server, which is convenient for users to open up their own permanent storage space to store address records. After the system starts, the DHCP Server reads data from the permanent storage space and puts it into the memory address pool. Users can write relevant configuration information into the permanent storage space and memory address pool through the hook function.

However, the DHCP Server embedded in the VxWorks operating system is bundled with the VxWorks kernel at startup. On the one hand, in the application program, the DHCP Server often uses the file system or database, and the file system or database is usually installed after the kernel is started. Only then will it be started, the embedded DHCP Server startup method lacks flexibility. On the other hand, during system operation, the DHCP Server memory address pool needs to be continuously updated according to user needs, but the current VxWorks operating system only provides the function of adding records, and cannot delete or update memory address pool records.

Contents of the invention

The purpose of the present invention is to provide a method for starting and updating a dynamic host configuration protocol server based on a VxWorks operating system.

The present invention aims at the deficiency of above-mentioned VxWorks embedded DHCP Server, makes two aspects of improvement. One is to modify the startup method of DHCP Server to make it independent of the VxWorks kernel, and the startup timing is controlled by the application program; the other is to use the database method to permanently store address records at the same time, so as to dynamically update the contents of the memory address pool.

The present invention is achieved like this: a kind of method based on VxWorks operating system realizes dynamic host configuration protocol server start and update, it is characterized in that comprising the following steps:

Make the VxWorks operating system kernel: When making the VxWorks kernel, the DHCP Server component is not added, so that the DHCP Server component and the VxWorks kernel are relatively independent;

Write the DHCP Server hook function: the hook function associates the permanent address storage area with the memory address pool, and the VxWorks operating system ensures the consistency of the records in the database and the memory address pool through the hook function;

After the VxWorks operating system kernel and database are started, call the application and start the DHCP Server;

Dynamically update the memory address pool of the DHCP Server: By operating the HASH table used by the VxWorks operating system to store memory address pool information, the dynamic update of record addition, record deletion, and record modification is realized.

When making the kernel of the VxWorks operating system, the header files relevant to the DHCP Server are extracted, and encapsulated into an application program of the DHCP Server by encoding;

After the VxWorks operating system is started, first initialize the database system, and then start the DHCPServer;

DHCP Server reads address records from the database and stores them in the memory address pool.

The VxWorks system provides two hook function interfaces. Through the hook function, the DHCPServer writes or reads the DHCP address information and lease information from the database to ensure the synchronization of the database and the memory area.

Described DHCP Server application program is used for the start of DHCP Server, comprises the following steps:

Bind the DHCP Server to the specified network interface device. The network interface device must support the standard Ethernet data frame format and be able to send and receive broadcast packets;

Pass the pointer of the hook function to the VxWorks operating system;

Start the dhcpStart thread to process requests from the DHCP Client;

The dhcpStart thread initializes the DHCP Server memory address pool, calls the hook function, and imports the contents of the permanent address storage area into the memory address pool.

The method further comprises the steps of:

Create the VxWorks operating system kernel, excluding DHCP Server;

Write a hook function to establish the relationship between the database and the memory data area;

After the system starts, automatically start the VxWorks kernel;

After the kernel starts, first initialize the database;

The application calls the system function and starts the DHCP Server;

After startup, the system calls the hook function to read all the records in the database into the memory address pool;

During system operation, the memory address pool is dynamically updated, including the addition, deletion and modification of memory address pool records;

While modifying the memory address pool, the application calls the hook function and updates the database records at the same time to keep in sync.

The memory address pool of described dynamic update DHCP Server is to realize by operating data structure hash-member and dhcp-resource in the HASH linked list:

When adding an address record, apply for a new hash-member and dhcp-resource, put the content of the address record into dhcp-resource, and then add it to the address list through hash-member;

When deleting an address record, the application program finds the address record to be deleted from the address record according to the keyword of the address record, finds the hash-member where the address record is located, deletes the hash-member from the address list, and releases the address record. The memory occupied by hash-member and dhcp-resource to avoid memory leaks.

When updating an address record, or find the record, modify the corresponding content in dhcp-resource, or find the record, delete the hash-member and dhcp-resource corresponding to the record, release the corresponding memory, and then add the modification The subsequent records are added to the address linked list.

Effects of the present invention: Solve the problems of inconvenient startup in the DHCP Server of VxWorks, imperfect function of updating address records and the like. It makes DHCP Server independent of VxWorks kernel. A database is used to permanently store address records. Can dynamically update the content in the memory address pool. Make DHCP Server easier to maintain and manage.

Description of drawings

Fig. 1 is a flow chart of DHCP Server operation;

FIG. 2 is a schematic diagram of storage of a memory address pool.

Detailed ways

The startup of DHCP Server independent of the VxWorks kernel is mainly divided into the following three steps:

First, the production of the VxWorks kernel is made. The DHCP Server component is not added when making the VxWorks kernel. Make DHCP Server and VxWorks kernel relatively independent.

Second, write the DHCP Server hook function. The hook function associates the permanent address storage area with the memory address pool. Through it, the VxWorks system ensures the consistency of the records in the database and the memory address pool.

Third, after the VxWorks operating system kernel and database are started, the application program is invoked to start the DHCP Server.

The dynamic update of the DHCP Server memory address pool includes adding records, deleting records and modifying records. The present invention has deeply studied the storage form of the memory address pool information, and found that VxWorks uses the HASH table to store information; by operating the HASH table, the dynamic update of the records is realized. .

The built-in DHCP Server in the VxWorks operating system is bound to the kernel. Generally, the network component of DHCP Server must be added when the kernel is made; and the startup of DHCP Server starts together with the kernel. This has a big disadvantage that, when the permanent address storage space can only be loaded after the kernel is started, the DHCP Server cannot read the address record from the database into the memory address pool at startup.

The improvement of the present invention is not to bind the DHCP Server component when making the VxWorks kernel. Instead, the header files related to DHCP Server are extracted and packaged into a DHCP Server application program through encoding. In this way, after the VxWorks system starts, you can initialize the database system and other related work first, and then start the DHCP Server. At this point, the DHCPServer can read the address record from the database and store it in the memory address pool.

The VxWorks operating system provides two hook function interfaces. Through the hook function, DHCPServer can write or read DHCP address information and lease information from the database to ensure the synchronization of the database and the memory area.

The advantage of adopting the database storage mode in the present invention is that it is convenient to read and write, and avoids complex character processing. In addition, the maintenance and query of the database are also very standardized.

The DHCP Server application program is responsible for starting the DHCP Server, and the implementation steps are as follows:

Bind DHCP Server to the specified network interface device. The network interface device must support the standard Ethernet data frame format and be able to send and receive broadcast packets.

Please pass the pointer of the hook function to the VxWorks operating system.

Start the dhcpStart thread. It is responsible for processing requests sent by DHCP Client. The main function of this thread is provided by VxWorks. It is provided to users in the form of a dynamic link library.

The dhcpStart thread initializes the DHCP Server memory address pool, calls the hook function, and imports the contents of the permanent address storage area into the memory address pool.

An important content of the present invention is to realize the dynamic updating of the DHCP Server memory address pool. The VxWorks operating system only provides additional functions for the memory address pool of the DHCP Server. If there is a wrong address record in the system memory address pool, such as incorrect parameters, or to delete a record in the address pool, the only way is to restart VxWorks, which will inevitably cause system interruption.

An in-depth analysis of the memory address pool of the DHCP Server shows that the memory address pool is stored in the form of a HASH linked list, and the system has a default record in the linked list, which is the head of the linked list of the memory address pool and cannot be deleted. Afterwards, the address record added by the user will be added to this linked list. But the system only provides the function of adding records to the address pool. It cannot be deleted or changed. After clarifying the structure of its address list, you can directly operate on the memory address pool, such as adding, deleting and modifying. This ensures that the memory address pool can be dynamically updated and maintained without restarting VxWorks to meet the client's DHCP request.

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Figure 1 is a flowchart of the operation of DHCP Server, which are described as follows:

Step 1-1: Make the VxWorks operating system kernel, excluding DHCP Server;

Step 1-2: Write the hook function to establish the relationship between the database and the memory data area;

Step 1-3: After the system starts, automatically start the VxWorks kernel;

Steps 1-4: After the kernel starts, first initialize the database;

Step 1-5: The application calls the system function and starts the DHCP Server;

Steps 1-6: After startup, the system calls the hook function to read all the records in the database into the memory address pool;

Steps 1-7: During system operation, dynamically update the memory address pool, including adding, deleting and modifying address pool records;

Steps 1-8: While modifying the memory address pool, the application calls the hook function and updates the database records at the same time to maintain synchronization.

FIG. 2 is a schematic diagram of storage of a memory address pool. The memory address pool of DHCP Server is stored in the form of HASH linked list. There are two very important data structures, hash-member and dhcp-resource. There are two members in the hash-member: a pointer to the next hash-member and a pointer to dhcp-resource. dhcp-resource is used to store each address record, including various parameters that may be provided to DHCPClient.

When an address record needs to be added, a new hash-member and dhcp-resource can be applied for. Put the content of the address record into the dhcp-resource. Then add it to the address list through hash-member.

When an address record needs to be deleted, the application program finds the address record to be deleted from the address record according to the keyword of the address record. After the hash-member where the address is recorded is found, the hash-member can be deleted from the address list, and the memory occupied by the hash-member and dhcp-resource can be released. to avoid memory leaks.

When an address record needs to be updated, there are two methods. One is to find the record and modify the corresponding content in dhcp-resource. Another method is to find the record, delete the hash-member and dhcp-resource corresponding to the record, and release the corresponding memory. Then add the modified record to the address linked list.

Claims (5)

1. Realize that based on vxworks operating system Dynamic Host Configuration Protocol server starts and method for updating, is characterized in that this method may further comprise the steps for 1 one kinds:

   Make the vxworks operating system kernel: when making the VxWorks kernel, the header file relevant with DHCPServer extracted, dress up the application program of a DHCP Server by encode seal, do not add DHCP Server assembly, make DHCP Server assembly and VxWorks kernel relatively independent;

   Write DHCP Server Hook Function: Hook Function associates database and memory address pond, vxworks operating system passes through Hook Function, content with the permanent address memory block during system start-up imports the memory address pond, upgrade data-base recording when the memory address pond is upgraded, guarantee the consistance that writes down in database and the memory address pond;

   After vxworks operating system kernel and database startup, invokes application starts DHCP Server;

   Dynamically update the memory address pond of DHCP Server: in order to the HASH of stored memory address pool information table, realize dynamically updating to record increase, record deletion, record modification by the operation vxworks operating system.
2. 2 realize that according to claim 1 Dynamic Host Configuration Protocol server starts and method for updating, it is characterized in that DHCP Server restarts in first initialization data storehouse system after vxworks operating system starts;

   DHCP Server reads the address and records in the memory address pond from database.
3. 3 realize that according to claim 1 Dynamic Host Configuration Protocol server starts and method for updating, it is characterized in that described VxWorks system provides two Hook Function interfaces, pass through Hook Function, DHCP Server writes dhcp address information and lease information or reads from database, to guarantee the synchronous of database and memory field.
4. 4 realize that according to claim 1 Dynamic Host Configuration Protocol server starts and method for updating, is characterized in that described DHCP Server application program is used for the startup of DHCP Server, may further comprise the steps:

   Binding DHCP Server is to the Network Interface Unit of appointment, and described Network Interface Unit must be supported the Ethernet data frame format of standard, can receive and dispatch broadcast packet;

   The pointer of Hook Function is passed to vxworks operating system;

   Start the dhcpStart thread, be used to handle the request that DHCP Client sends;

   Hook Function is called in dhcpStart thread initialization DHCP Server memory address pond, with the content importing memory address pond of database.
5. 5 realize that according to claim 1 Dynamic Host Configuration Protocol server starts and method for updating, and the memory address pond that it is characterized in that the described DHCP of dynamically updating Server is to realize by data structure hash_member and dhcp_resource in the operation HASH chained list:

   When increasing address record, apply for new hash_member and dhcp_resource, the content that write down the address is put into dhcp_resource, be added in the address link list by hash_member then;

   When deleting address record, application program finds the address record of needs deletion from the record of address according to the key word of address record, after finding the ha sh_member that this address is recorded in, this hash_member is deleted from address link list, and discharge this hash_member and the shared internal memory of dhcp_resource, to avoid memory overflow;

   When upgrading address record, or find this record, the corresponding contents among the dhcp_resource is revised, or find this record, delete pairing hash_member of this record and dhcp_resource, discharge corresponding internal memory, increase amended being recorded in the address link list again.

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