socket程式設計(2)—— 一對多通訊
阿新 • • 發佈:2018-12-10
1 一對多模型,TCP的程式設計步驟
服務端: 1、socket()獲得一個sockfd。注意第二個引數必須SOCK_STREAM. 2、準備通訊地址(必須伺服器的) 3、bind()繫結。(開放了埠,允許客戶端連線) 4、監聽客戶端 listen()函式 5、等待客戶端的連線 accept(),返回用於互動的socket描述符 6、使用第5步返回sockt描述符,進行讀寫通訊。 7、關閉sockfd。
客戶端: 客戶端的程式碼與一對一的一樣。注意第二個引數必須SOCK_STREAM.
TCP一對多模型,有兩類描述符: 第一步的描述符不再參與資訊互動,只是等待客戶端的連線(accept),accept()在客戶端連線上來後,會返回一個新的描述符,用於讀寫通訊。
#include<stdio.h> #include<stdlib.h> #include<string.h> #include<sys/socket.h> #include<netinet/in.h> #include<arpa/inet.h> #include<unistd.h> int main(){ int sockfd = socket(AF_INET,SOCK_STREAM,0); if (sockfd == -1){ perror("socket"),exit(-1); } struct sockaddr_in addr; addr.sin_family = AF_INET; addr.sin_port = htons(2222); addr.sin_addr.s_addr = inet_addr("192.168.66.11"); int res = bind(sockfd,(struct sockaddr*)&addr, sizeof(addr)); if (res == -1){ perror("bind"),exit(-1); } printf("bind ok\n"); listen(sockfd,100);//監聽 struct sockaddr_in client; socklen_t len = sizeof(client); int fd = accept(sockfd,(struct sockaddr*)&client,&len); char *from = inet_ntoa(client.sin_addr);//十六進位制轉點分十進位制 printf("%s連線成功\n",from); char buf[100] = {}; res = read(fd,buf,sizeof(buf)); printf("接受了%d位元組,內容:%s",res,buf); write(fd,"welcome",7); close(fd); close(sockfd); 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> int main(){ int sockfd = socket(AF_INET,SOCK_STREAM,0); if (sockfd == -1){ perror("socket"),exit(-1); } struct sockaddr_in addr; addr.sin_family = AF_INET; addr.sin_port = htons(2222);//連線埠 addr.sin_addr.s_addr = inet_addr("192.168.66.11");//都是伺服器的,改成連線IP int res = connect(sockfd,(struct sockaddr*)&addr, sizeof(addr)); if (res == -1){ perror("connect"),exit(-1); } printf("連線成功\n"); write(sockfd,"hello",5); char buf[100] = {}; res = read(sockfd,buf,sizeof(buf)); printf("讀到了%d位元組,內容:%s\n",res,buf); close(sockfd); return 0; }
上面的服務端還只是實現了一對一的通訊,一對多通訊加一個while迴圈即可。
2 練習
1、在客戶端加上輸入功能,允許傳送不同的資訊,並且客戶端和伺服器端程式碼要支援多次輸入和輸出(讀寫上加迴圈),輸入bye退出。客戶端傳送的內容改為輸入,伺服器發回給客戶端的內容改成客戶端的輸入。
2、可以考慮在伺服器端啟動多程序fork(),支援多個客戶端的並行。
server.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<signal.h>
int sockfd;
void fa(int signo){
printf("伺服器正在關閉\n");
sleep(1);
close(sockfd);
exit(0);
}
int main(){
printf("ctrl+c退出伺服器\n");
signal(SIGINT,fa);
int sockfd = socket(AF_INET,SOCK_STREAM,0);
if (sockfd == -1){
perror("socket"),exit(-1);
}
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(2222);
addr.sin_addr.s_addr = inet_addr("192.168.66.11");
int reuseaddr = 1;//解決地址已被佔用問題
setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,
&reuseaddr,sizeof(reuseaddr));
int res = bind(sockfd,(struct sockaddr*)&addr,
sizeof(addr));
if (res == -1){
perror("bind"),exit(-1);
}
printf("bind ok\n");
listen(sockfd,100);//監聽
while (1){
struct sockaddr_in client;
socklen_t len = sizeof(client);
int fd = accept(sockfd,(struct sockaddr*)&client,
&len);//阻塞函式
char *from = inet_ntoa(client.sin_addr);
printf("%s連線成功\n",from);
pid_t pid = fork();
if (pid == 0){
char buf[100] = {};
while (1){
res = read(fd,buf,sizeof(buf));
printf("接受了%d位元組,內容:%s\n",res,buf);
if (res <= 0){//包括0和-1
break;
}
if (strcmp(buf,"bye") == 0){
break;
}
write(fd,buf,strlen(buf));
memset(buf,0,sizeof(buf));
}
close(fd);
exit(0);
}
close(fd);
}
}
client.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
int main(){
int sockfd = socket(AF_INET,SOCK_STREAM,0);
if (sockfd == -1){
perror("socket"),exit(-1);
}
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(2222);//連線埠
addr.sin_addr.s_addr = inet_addr("192.168.66.11");//都是伺服器的,改成連線IP
int res = connect(sockfd,(struct sockaddr*)&addr,sizeof(addr));
if (res == -1){
perror("connect"),exit(-1);
}
printf("連線成功\n");
char buf[100] = {};
while (1){
memset(buf,0,sizeof(buf));//buf清0
printf("請輸入要說的話\n");
scanf("%s",buf);
write(sockfd,buf,strlen(buf));
if (strcmp(buf,"bye") == 0){//退出的合適位置
break;
}
memset(buf,0,sizeof(buf));//buf清0
res = read(sockfd,buf,sizeof(buf));
printf("讀到了%d位元組,內容:%s\n",res,buf);
}
close(sockfd);
return 0;
}