TCP并发服务器

   
    TCP服务器老师平时教我们写过，现在学习ARM，接触硬件的时候了，感觉网络编程渐渐远去了，特地写写回顾一下所学知识。
    其方法就是将回射服务器改写成并发的，问题就在于要创建子进程，而且是循环创建子进程，与多个客户端建立好连接后让子进程完成数据的收发。

    head.h
    受老师的影响，头文件习惯放在/usr/include/目录下

#ifndef _HEAD_H_
#define _HEAD_H_ 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <dirent.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define handler_error(msg)     do{\
    perror(msg);exit(EXIT_FAILURE);}while(0) /*just do once*/


#endif

    server.c

#include <head.h>

#define handler_error(msg) do{\
    perror(msg);exit(EXIT_FAILURE);}while(0)

void handler(int signum)//信号处理函数
{
    waitpid(-1,NULL,WNOHANG);
    return;
}


int do_client(int sockfd)
{
    int n;
    char buf[1024];

    while(1)
    {
        //接受数据
        n = read(sockfd,buf,sizeof(buf) - 1);
        buf[n] = '\0';

        printf("Recv %d bytes : %s.\n",n,buf);

        //发回去
        write(sockfd,buf,n);

        if(strncmp(buf,"quit",4) == 0)
            break;

    }

    return 0;
}


//./server ip port
int main(int argc, const char *argv[])
{
    int connect_fd,pid;
    struct sockaddr_in peer_addr;
    socklen_t addrlen = sizeof(struct sockaddr);
    int listen_fd;
    struct sockaddr_in server_addr;

    if(argc < 3)
    {
        fprintf(stderr,"Usage : %s ip port.\n",argv[1]);
        exit(EXIT_FAILURE);
    }

    if(signal(SIGCHLD,handler) == SIG_ERR)
    {
        handler_error("signal");
    }

     listen_fd = socket(AF_INET,SOCK_STREAM,0);
     if(listen_fd < 0){
         handler_error("socket");
     }

     memset(&server_addr,0,sizeof(server_addr));
     server_addr.sin_family = AF_INET;
     server_addr.sin_port = htons(atoi(argv[2]));
     server_addr.sin_addr.s_addr = inet_addr(argv[1]);

     //绑定地址
     if(bind(listen_fd,(struct sockaddr *)&server_addr,sizeof(server_addr)) < 0)
     {
         handler_error("bind");
     }

     //设置socket为监听状态
     listen(listen_fd,5);

     printf("listen ...\n");

     while(1)
     {

        connect_fd = accept(listen_fd,(struct sockaddr *)&peer_addr,&addrlen);
        if(connect_fd < 0)
            handler_error("accept");

        printf("*****************************\n");
        printf("Peer Ip  :%s.\n",inet_ntoa(peer_addr.sin_addr));
        printf("Peer Port:%d.\n",ntohs(peer_addr.sin_port));
        printf("*****************************\n");

        //创建子进程和客户端进行收发数据
        pid = fork();
        if(pid < 0){
            handler_error("fork");
        }

        if(pid == 0)
        {
            do_client(connect_fd);
            exit(EXIT_FAILURE);
        }

        //避免父进程fd浪费
        close(connect_fd);
     }

    return 0;
}

    client.c

#include <head.h>

//./client  ip  port
int main(int argc, const char *argv[])
{
    int n;
    char buf[1024];
    int sockfd;
    struct sockaddr_in server_addr;

    //创建流式socket
    sockfd = socket(AF_INET,SOCK_STREAM,0);
    if(sockfd < 0){
        handler_error("socket");
    }

    memset(&server_addr,0,sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(atoi(argv[2]));
    server_addr.sin_addr.s_addr = inet_addr(argv[1]);

    //int connect(int sockfd, const struct sockaddr *addr,socklen_t addrlen);
    if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof(server_addr)) < 0){
        handler_error("connect");
    }

    //connect成功返回，表示三次握手完成
    while(1)
    {
        printf(">");

        fgets(buf,sizeof(buf),stdin);
        buf[strlen(buf) - 1] = '\0';

        write(sockfd,buf,strlen(buf));


        memset(buf,0,sizeof(buf));
        n = read(sockfd,buf,sizeof(buf) - 1);
        buf[n] = '\0';

        printf("Recv %d bytes : %s.\n",n,buf);
    }

    return 0;
}

    截图效果：