Socket编程

Socket编程，服务器和客服端的实现

//服务端server.c#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>#define SERVPORT 6000 /*服务器监听端口号 */#define BACKLOG 10 /* 最大同时连接请求数 */#define MAXDATASIZE 100main(){ char buf[MAXDATASIZE]; 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; 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) {  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));  if (!fork())  { /* 子进程代码段 */   if ((recvbytes=recv(client_fd, buf, MAXDATASIZE, 0)) ==-1)   {    perror("recv出错！");    close(client_fd);    exit(0);   }   buf[recvbytes] = '\0';   printf("from client Received: %s",buf);   if (send(client_fd, "thanks!\n", 8, 0) == -1)    perror("send出错！");   close(client_fd);   exit(0);  }  close(client_fd); }}//客户端client.c#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>#define SERVPORT 6000#define MAXDATASIZE 100main(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); } 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); bzero(&(serv_addr.sin_zero),8); if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1) {  perror("connect出错！");  exit(1); }if (send(sockfd, "hello!\n", 7, 0) == -1) {  perror("send出错！");  exit(1); }  if ((recvbytes=recv(sockfd, buf, MAXDATASIZE, 0)) ==-1) {  perror("recv出错！");  exit(1); } buf[recvbytes] = '\0'; printf("Received: %s",buf); close(sockfd);}

UDP

//<udp_client.c>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/socket.h>#include <arpa/inet.h>int main(void){int sfd; char buf[1024]; int n, i;struct sockaddr_in serv_addr, cli_addr;socklen_t len;sfd = socket(AF_INET, SOCK_DGRAM, 0);memset(&serv_addr, 0, sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_port = htons(8000);inet_pton(AF_INET, "192.168.0.36", &serv_addr.sin_addr.s_addr);while(1) {if(fgets(buf, 1024, stdin) == NULL)break;sendto(sfd, buf, strlen(buf), 0, (struct sockaddr *)&serv_addr, sizeof(serv_addr));n = recvfrom(sfd, buf, 1024, 0, NULL, NULL);write(STDOUT_FILENO, buf, n);}close(sfd);return 0;}//<udp_server.c>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/socket.h>#include <arpa/inet.h>int main(void){int sfd; char buf[1024]; int n, i;struct sockaddr_in serv_addr, cli_addr;socklen_t len;sfd = socket(AF_INET, SOCK_DGRAM, 0);memset(&serv_addr, 0, sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_port = htons(8000);serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);bind(sfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));while(1) {len = sizeof(cli_addr);n = recvfrom(sfd, buf, 1024, 0, (struct sockaddr *)&cli_addr, &len);for(i = 0; i < n; i++)buf[i] = toupper(buf[i]);sendto(sfd, buf, n, 0, (struct sockaddr *)&cli_addr, len);}close(sfd);return 0;}