注意：sockaddr地址结构体中的成员，除了sin_family之外，其他的成员都要使用网络字节序（高地址先存，低地址后存，而一般的基于inter的CPU都是低地址先存，高地址后存），所以我们要把这些成员改变为网络字节序（htonl(INADDR_ANY);相关的操作）
client和server均在本机。
服务器端代码：
#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <sys/wait.h>#include <arpa/inet.h>#include <unistd.h>
#define SERVPORT 3333 /*服务器监听端口号 */#define BACKLOG 10 /* 最大同时连接请求数 */main(){ int sockfd,client_fd; /*sock_fd：监听socket；client_fd：数据传输socket */ struct sockaddr_in my_addr; /* 本机地址信息 */ struct sockaddr_in remote_addr; /* 客户端地址信息 */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("socket创建出错！"); exit(1); }
my_addr.sin_family=AF_INET; my_addr.sin_port=htons(SERVPORT); my_addr.sin_addr.s_addr = INADDR_ANY; //zb: servaddr.sin_addr.s_addr = htonl(INADDR_ANY); bzero(&(my_addr.sin_zero),8);
if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) { perror("bind出错！"); exit(1); } if (listen(sockfd, BACKLOG) == -1) { perror("listen出错！"); exit(1); } while(1) { socklen_t sin_size = sizeof(struct sockaddr_in); if ((client_fd = accept(sockfd, (struct sockaddr *)&remote_addr, &sin_size)) == -1) { perror("accept出错"); continue; }
printf("received a connection from %s/n", inet_ntoa(remote_addr.sin_addr)); /***** zb add *****/ char str[INET_ADDRSTRLEN]; printf("received from %s at PORT %d/n", inet_ntop(AF_INET, &remote_addr.sin_addr, str, sizeof(str)), ntohs(remote_addr.sin_port)); /***** zb end *****/
if (!fork()) { /* 子进程代码段 */ //zb: while(1){ //write(client_fd, "Hello, you are connected!/n", strlen("Hello,... ed!/n")); if (send(client_fd, "Hello, you are connected!/n", 26, 0) == -1) perror("send出错！"); /***** zb add *****/ char bug[128] = {0}; //read(client_fd, bug, sizeof(bug)); if read == 0, means link break! if (recv(client_fd, bug, sizeof(bug), 0) == -1) perror("recv出错！"); printf("Received client : %s/n",bug); /***** zb end *****/ // } /*end while*/ close(client_fd); exit(0); }
close(client_fd); }}
客户端代码：
#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <unistd.h>#define SERVPORT 3333#define MAXDATASIZE 100 /*每次最大数据传输量 */
main(int argc, char *argv[]){ int sockfd, recvbytes; char buf[MAXDATASIZE]; struct hostent *host; struct sockaddr_in serv_addr;
if (argc < 2) { fprintf(stderr,"Please enter the server's hostname!/n"); exit(1); }
/* zb: make argv[1] = "localhost" */ if((host=gethostbyname(argv[1]))==NULL) { herror("gethostbyname出错！"); exit(1); } if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){ perror("socket创建出错！"); exit(1); }
serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(SERVPORT); serv_addr.sin_addr = *((struct in_addr *)host->h_addr); //zb: inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr); // serv_addr.sin_addr.s_addr = inet_addr("192.168.0.1"); // inet_aton("127.0.0.1",&serv_addr.sin_addr); bzero(&(serv_addr.sin_zero),8);
if (connect(sockfd, (struct sockaddr *)&serv_addr, / sizeof(struct sockaddr)) == -1) { perror("connect出错！"); exit(1); } //zb: while(1){ if ((recvbytes=recv(sockfd, buf, MAXDATASIZE, 0)) ==-1) { perror("recv出错！"); exit(1); }
buf[recvbytes] = '/0'; printf("Received: %s",buf); /***** zb add *****/ if (send(sockfd, "Yes, I see, over !/n", 19, 0) == -1) perror("send出错！"); /***** zb add *****/ // } /*end while*/ close(sockfd);}
