Linux-Tcp-IP

 /* tcpcli.c */
#include <stdio.h>
#include <stdlib.h>
#include <string.h> 
#include <unistd.h> 
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define DEFAULT_PORT 8800

int main(int argc, char** argv)
{
    int cPort = DEFAULT_PORT;
    int cClient = 0;
    int cLen = 0;
    struct sockaddr_in cli;
    char cbuf[4096] = {0};
    
    if(argc < 2)
    {
        printf("Uasge: client[server IP address]\n");
        return -1;
    }
    
    memset(cbuf, 0, sizeof(cbuf));
    
    cli.sin_family = AF_INET;
    cli.sin_port = htons(cPort);
    cli.sin_addr.s_addr = inet_addr(argv[1]);
    
    cClient = socket(AF_INET, SOCK_STREAM, 0);
    if(cClient < 0)
    {
        printf("socket() failure!\n");
        return -1; 
    }
    
    if(connect(cClient, (struct sockaddr*)&cli, sizeof(cli)) < 0)
    {
        printf("connect() failure!\n");
        return -1;
    }
    
    cLen = recv(cClient, cbuf, sizeof(cbuf),0);    
    if((cLen < 0)||(cLen == 0))
    {
          printf("recv() failure!\n");
        return -1;
    }
    printf("recv() Data From Server: [%s]\n", cbuf);
    
    close(cClient);
    
    return 0;
}

//编译代码：gcc -o tcp_clt  client_tcp.c

//执行命令：./tcp_clt 192.168.0.230

//TCP scoket服务端程序代码

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

/********************************************************************* 
*filename: tcpserver.c 
*purpose:tcp服务端程序 
********************************************************************/
int main(int argc, char ** argv) 
{ 
    int sockfd,new_fd;　　　　 /* 监听socket: sock_fd,数据传输socket: new_fd */ 
    struct sockaddr_in my_addr; /* 本机地址信息 */ 
    struct sockaddr_in their_addr; /* 客户地址信息 */ 
    unsigned int sin_size, myport, lisnum; 
 
    if(argv[1])  myport = atoi(argv[1]); 
    else myport = 8800; 
 
    if(argv[2])  lisnum = atoi(argv[2]); 
    else lisnum = 2; 
 
    if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) { 
        perror("socket"); 
        exit(1); 
    } 
 printf("socket %d ok \n",myport);

    my_addr.sin_family=PF_INET; 
    my_addr.sin_port=htons(myport); 
    my_addr.sin_addr.s_addr = INADDR_ANY; 
    bzero(&(my_addr.sin_zero), 0); 
    if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) { 
        perror("bind"); 
        exit(1); 
    } 
 printf("bind ok \n");
 
    if (listen(sockfd, lisnum) == -1) { 
        perror("listen"); 
        exit(1); 
    }
 printf("listen ok \n");
 
 /*
    while(1) { 
        sin_size = sizeof(struct sockaddr_in); 
        if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) { 
            perror("accept"); 
            continue; 
        }

        printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr)); 
        if (!fork()) { //子进程代码段 
            if (send(new_fd, "Hello, world!\n", 14, 0) == -1) { 
                perror("send"); 
                close(new_fd); 
                exit(0); 
            } 
        } 
        close(new_fd); //父进程不再需要该socket
        waitpid(-1,NULL,WNOHANG);//等待子进程结束，清除子进程所占用资源
    } 
 */

    sin_size = sizeof(struct sockaddr_in); 
    if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) { 
        perror("accept"); 
  exit(0); 
    } 
    printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));

 int   step = 0;
 while(1) {
  char  szSnd[63] = {0};
  sprintf(szSnd,"i am server [%d]\n",step);
  step++;
        if (send(new_fd, szSnd, strlen(szSnd), 0) == -1) { 
            perror("send"); 
            close(new_fd); 
            break;
        }

  printf("send msg: %s \n",szSnd);

  sleep(1);
 }

 exit(0); 
}
}

//编译指令：gcc -o tcp_srv tcpserver.c 

//执行服务器端程序：./tcp_srv

//创建成功，绑定端口成功，监听成功后，循环发送i am server字符串。