#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>  

#define MAXLINE 1000

#define SERV_PORT 9931  

void doprocessing(int sock, struct sockaddr_in cliaddr)

{

    int n;  

    char str[INET_ADDRSTRLEN];

    char *buf = (char *)malloc(MAXLINE);

    char *reply = (char *)malloc(MAXLINE*2);

    memset(buf, '\0', MAXLINE);

    while (1) {

        n = read(sock, buf, MAXLINE);

        strcpy(reply,"I got your message: ");

        if (n < 0) {

            perror("Error reading from socket!");

            return;

        } else {

            printf("Connect from %s:%d\n", inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)), ntohs(cliaddr.sin_port));

	    strcat(reply,buf);

            printf("receive %s\n",buf);

            write(sock, reply, MAXLINE);

        }

	memset(buf,0,sizeof(char)*MAXLINE);

	memset(reply,0,sizeof(char)*MAXLINE);

    }

    free(reply);

    free(buf);

}  

int main(void)

{

    struct sockaddr_in servaddr, cliaddr;  

    int listenfd, connfd, pid;

    socklen_t cliaddr_len = sizeof(cliaddr);  

    listenfd = socket(AF_INET, SOCK_STREAM, 0);

    if (listenfd < 0) {

        perror("Error opening socket!");

        exit(-1);

    }  

    memset(&servaddr, 0, sizeof(struct sockaddr_in));

    servaddr.sin_family = AF_INET;

    servaddr.sin_addr.s_addr = inet_addr("10.13.81.182");

    servaddr.sin_port = htons(SERV_PORT);     

    bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));  

    listen(listenfd, 2000);  

    printf("server服务器开始等待客户端连接 ...\n");  

    while (1) {

        connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);  

        pid = fork();  

        if (pid == -1) {

            perror("call to fork");

            exit(-1);

        } else if (pid == 0) {

            close(listenfd);

            doprocessing(connfd, cliaddr);

            exit(0);

        } else {

            close(connfd);

        }

    }  

    return 0;

}

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>  

#define MAXLINE 1000

#define SERV_PORT 9931  

int main(int argc, char *argv[])

{  

	struct sockaddr_in servaddr;

	char *buf = (char *)malloc(MAXLINE);

	char *rec = (char *)malloc(MAXLINE);

	int servfd, n;  

	servfd = socket(AF_INET, SOCK_STREAM, 0);  

	memset(&servaddr, 0, sizeof(servaddr));

	servaddr.sin_family = AF_INET;

	servaddr.sin_addr.s_addr = inet_addr("10.13.81.182");

	servaddr.sin_port = htons(SERV_PORT);  

	connect(servfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

	while (fgets(buf, MAXLINE, stdin)!= NULL) {

		write(servfd, buf, strlen(buf));  

		n = read(servfd, rec, MAXLINE);

		if (n == 0) {

			perror("The other side has been closed.");

			exit(-1);

		} else {

			printf("从服务器返回的信息为:%s\n", rec);

		}

		memset(rec,0,sizeof(char)*MAXLINE);

		memset(buf,0,sizeof(char)*MAXLINE);

	}

	close(servfd);

	return 0;

}