Question

我有一个C脚本，它连接到带有套接字的远程服务器并写入命令。

我必须尽快做到这一点，我需要从源ip addressess切换。问题是，当我从ip地址切换时，绑定会慢下来几秒钟。

我找不到解决方案。

代码：

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h> 

int main()
{

    struct sockaddr_in source, destination = {};  //two sockets declared as previously
    int sock = 0;
    int n = 0;
    int datalen = 0;
    int pkt = 0;


    char* ips[3] = {"10.0.0.1", "10.0.0.2", "10.0.0.3"};

    uint8_t *send_buffer;
    char recv_buffer[11];

    struct sockaddr_storage fromAddr;   // same as the previous entity struct sockaddr_storage serverStorage;
    unsigned int addrlen;  //in the previous example socklen_t addr_size;
    struct timeval tv;
    tv.tv_sec = 3;  /* 3 Seconds Time-out */
    tv.tv_usec = 0;

    /*Inititalize source to zero*/
    memset(&source, 0, sizeof(source));       //source is an instance of sockaddr_in. Initialization to zero
    /*Inititalize destinaton to zero*/
    memset(&destination, 0, sizeof(destination));


        /* setting the destination, i.e our OWN IP ADDRESS AND PORT */
        destination.sin_family = AF_INET;                 
        // destination.sin_addr.s_addr = inet_addr("123.456.789.123");  
        destination.sin_port = htons(43); 


            /*---- Configure settings of the source address struct, WHERE THE PACKET IS COMING FROM ----*/
        /* Address family = Internet */
        source.sin_family = AF_INET;    
        /* Set IP address to localhost */   
        // source.sin_addr.s_addr = INADDR_ANY;
        /* Set port number, using htons function to use proper byte order */
        source.sin_port = htons(43); 



        /* Set all bits of the padding field to 0 */
        memset(source.sin_zero, '\0', sizeof source.sin_zero); //optional


    int i;
    for (i=0; i<60; i++) {  

        /* creating the socket */         
        if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) 
            printf("Failed to create socket\n");

        /*set the socket options*/
        setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(struct timeval));



        if(inet_pton(AF_INET, ips[i%3], &source.sin_addr)<=0) //this is where is switch the ip addresses
        {
            printf("\n inet_pton error occured\n");
            return 1;
        } 


        /*bind socket to the source WHERE THE PACKET IS COMING FROM*/
        if (bind(sock, (struct sockaddr *) &source, sizeof(source)) < 0) 
            printf("Failed to bind socket");



        if(inet_pton(AF_INET, "94.198.154.139", &destination.sin_addr)<=0)
        {
            printf("\n inet_pton error occured\n");
            return 1;
        } 

        if(connect(sock, (struct sockaddr *)&destination, sizeof(destination)) < 0)
        {
           printf("\n Error : Connect Failed \n");
           return 1;
        } 

        printf("check\n");

        n = write(sock,"is liveresults.nl\r\n",21);
        if (n < 0) error("ERROR writing to socket");

        while ( (n = read(sock, recv_buffer, sizeof(recv_buffer)-1)) > 0)
        {
            recv_buffer[n] = 0;
            if(fputs(recv_buffer, stdout) == EOF)
            {
                printf("\n Error : Fputs error\n");
            }
        } 

        if(n < 0)
        {
            printf("\n Read error \n");
        } 


        close(sock);

    }

    return 0;
}

编辑：我必须注意到每个ip的第一个循环都会减慢速度。因为我有3个IP地址。在第一轮之后，每个绑定会减慢几秒钟。

Answer 1

我必须将本地端口绑定到0而不是与传出端口相同的端口。

当我切换源IP地址时，C套接字绑定减慢

1 个答案: