Linux内核3.7 TCP Fast Open验证实例

Linux内核在3.6和3.7合入了TCP Fast Open特性，在3.7.3版本上验证了一下，I did it!

以下是C语言实例（）：

server端代码：

      

#include /* See NOTES */

#include

#include

#include

int main(){

    int portno = 5060;

    socklen_t clilen;

    char buffer[256];

    struct sockaddr_in serv_addr, cli_addr;

    int cfd;

    int sfd = socket(AF_INET, SOCK_STREAM, 0);   // Create socket

    

    bzero((char *) &serv_addr, sizeof(serv_addr));

    serv_addr.sin_family = AF_INET;

    serv_addr.sin_addr.s_addr = INADDR_ANY;

    serv_addr.sin_port = htons(portno);

    bind(sfd, &serv_addr,sizeof(serv_addr));      // Bind to well known address

    

    int qlen = 5;                 // Value to be chosen by application

    int err = setsockopt(sfd, IPPROTO_TCP/*SOL_TCP*/, 23/*TCP_FASTOPEN*/, &qlen, sizeof(qlen));

    

    listen(sfd,1);                // Mark socket to receive connections

    cfd = accept(sfd, NULL, 0);   // Accept connection on new socket

    while(1){

        int len = read(cfd,buffer,256);

        if(len)

             printf("tcp fast open: %s\\n",buffer);

        else

             break;

        // read and write data on connected socket cfd

    }

    

    close(cfd);

}

client端代码：

#include

#include

#include  

#include

int main(){

    struct sockaddr_in serv_addr;

    struct hostent *server;

    char *data = "Hello, tcp fast open";

    int data_len = strlen(data);    

    

    int sfd = socket(AF_INET, SOCK_STREAM, 0);

    server = gethostbyname("localhost");

    

    bzero((char *) &serv_addr, sizeof(serv_addr));

    serv_addr.sin_family = AF_INET;

    bcopy((char *)server->h_addr, 

         (char *)&serv_addr.sin_addr.s_addr,

         server->h_length);

    serv_addr.sin_port = htons(5060);

    int len = sendto(sfd, data, data_len, 0x20000000/*MSG_FASTOPEN*/, 

                (struct sockaddr *) &serv_addr, sizeof(serv_addr));

    printf("error: %s\\n",strerror(errno));

    close(sfd);

    sleep(5);    

}

执行结果：

# ./server        

tcp fast open: Hello, tcp fast open

# ./client        

error: Success 

环境：Fedora 18 升级内核到3.7.3；glibc 2.17；gcc 4.7.2

记得要执行： echo 1 > /proc/sys/net/ipv4/tcp_fastopen