迴圈伺服器，併發伺服器模型以及I/O多路轉接模型
阿新 • • 發佈：2019-02-15
一、基於TCP/IP協議的基本迴圈伺服器
tcp_server.c
tcp_client.c#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/stat.h> #include <netdb.h> #define PORT 3333 #define MAX_SIZE 1024 int main() { int sockfd; int new_fd; struct sockaddr_in server_addr; struct sockaddr_in client_addr; int n_read; int ser_size; int opt = 1; char buffer[MAX_SIZE]; if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0) { perror("socket error!\n"); exit(1); } printf("socket success.............!\n"); if(setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt)) < 0) { perror("set socket option error!\n"); exit(1); } bzero(&server_addr,0); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(PORT); server_addr.sin_addr.s_addr = inet_addr("192.168.1.10"); if(bind(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0) { perror("bind error!\n"); exit(1); } printf("bind success.............!\n"); listen(sockfd,5); printf("listen success.............!\n"); printf("accepting..................!\n"); while(1) { ser_size = sizeof client_addr; if((new_fd = accept(sockfd,(struct sockaddr *)&client_addr,&ser_size)) < 0) { perror("accept error!\n"); exit(1); } printf("accept success.................!\n"); //read\recv printf("reading............!\n"); n_read = read(new_fd,buffer,sizeof(buffer)); if(n_read < 0) { perror("read client msg error!\n"); exit(1); } buffer[n_read] = '\0'; printf("recv msg = %s\n",buffer); } return 0; }
迴圈伺服器能不斷地接收客戶端傳送過來的資訊，但是在面對多個客戶端時，伺服器必須等待第一個客戶端傳送資訊才能接受其他客戶端發來的資訊。#include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <netdb.h> #define PORT 3333 #define MAX_SIZE 1024 int main(int argc, char *argv[]) { if(argc != 2) { printf("Please input server ip!\n"); exit(1); } int sockfd; int n_write; struct sockaddr_in server_addr; char buffer[MAX_SIZE]; if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0) { perror("client socket error!\n"); exit(1); } bzero(&server_addr,0); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(PORT); server_addr.sin_addr.s_addr = inet_addr(argv[1]); if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0) { perror("connect server error!\n"); exit(1); } while(1) { memset(buffer,0,sizeof(buffer)); printf("Please input send msg:\n"); gets(buffer); n_write = write(sockfd,buffer,strlen(buffer)); if(n_write == -1) { perror("send to server msg error!\n"); exit(1); } } return 0; }
由此，我們使用併發伺服器，通過建立子程序，使得多個客戶端能隨時發信息給伺服器
併發伺服器：
併發客戶端：#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/stat.h> #include <netdb.h> #define PORT 3333 #define MAX_SIZE 1024 void * read_msg(void *arg) { int n_read; int new_fd = *((int *)arg); char buffer[MAX_SIZE]; printf("new_fd = %d\n",new_fd); while(1) { memset(buffer,0,sizeof(buffer)); n_read = read(new_fd,buffer,sizeof(buffer)); if(n_read < 0) { perror("recv client msg error!\n"); exit(1); } if(n_read == 0) { printf("client is close!!\n"); close(new_fd); pthread_exit(NULL); } buffer[n_read] = '\0'; printf("recv msg:%s\n",buffer); } } int main() { int sockfd; int new_fd; struct sockaddr_in server_addr; struct sockaddr_in client_addr; int n_read; int ser_size; int opt = 1; char buffer[MAX_SIZE]; pthread_t id; if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0) { perror("socket error!\n"); exit(1); } printf("socket success.............!\n"); if(setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt)) < 0) { perror("set socket option error!\n"); exit(1); } bzero(&server_addr,0); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(PORT); server_addr.sin_addr.s_addr = inet_addr("192.168.1.10"); if(bind(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0) { perror("bind error!\n"); exit(1); } printf("bind success.............!\n"); listen(sockfd,5); printf("listen success.............!\n"); printf("accepting..................!\n"); while(1) { ser_size = sizeof client_addr; if((new_fd = accept(sockfd,(struct sockaddr *)&client_addr,&ser_size)) < 0) { perror("accept error!\n"); exit(1); } printf("accept success.................!\n"); pthread_create(&id,NULL,read_msg,&new_fd); } return 0; }
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#define PORT 3333
#define MAX_SIZE 1024
int main(int argc, char *argv[])
{
if(argc != 2)
{
printf("Please input server ip!\n");
exit(1);
}
int sockfd;
int n_write;
struct sockaddr_in server_addr;
char buffer[MAX_SIZE];
if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("client socket error!\n");
exit(1);
}
bzero(&server_addr,0);
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = inet_addr(argv[1]);
if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0)
{
perror("connect server error!\n");
exit(1);
}
while(1)
{
memset(buffer,0,sizeof(buffer));
printf("Please input send msg:\n");
gets(buffer);
n_write = write(sockfd,buffer,strlen(buffer));
if(n_write == -1)
{
perror("send to server msg error!\n");
exit(1);
}
}
return 0;
}
併發伺服器模型的缺點是：客戶端不再和伺服器互動時，其多執行緒仍在工作，比較耗費CPU 的資源。
I/O多路轉接模型：
利用一個“監聽者”，當有客戶端發出連線請求及客戶端傳送資訊時，才會和伺服器連線。
伺服器程式碼：
#include <stdlib.h>
#include <stdio.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>
#include<arpa/inet.h>
#include<ctype.h>
#define portnumber 8000
#define MAX_LINE 80
int main(void)
{
int lfd;
int cfd;
int sfd;
int rdy;
struct sockaddr_in sin;
struct sockaddr_in cin;
int client[FD_SETSIZE];
int maxi;
int maxfd;
fd_set rset;
fd_set allset;
socklen_t addr_len;
char buffer[MAX_LINE];
int i;
int n;
int len;
int opt = 1;
char addr_p[20];
bzero(&sin,sizeof(struct sockaddr_in));
sin.sin_family=AF_INET;
sin.sin_addr.s_addr=htonl(INADDR_ANY);
sin.sin_port=htons(portnumber);
if((lfd=socket(AF_INET,SOCK_STREAM,0))==-1)
{
fprintf(stderr,"Socket error:%s\n\a",strerror(errno));
exit(1);
}
printf("socket!\n");
setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
if(bind(lfd,(struct sockaddr *)(&sin),sizeof(struct sockaddr))==-1)
{
fprintf(stderr,"Bind error:%s\n\a",strerror(errno));
exit(1);
}
printf("bind!\n");
if(listen(lfd,20)==-1)
{
fprintf(stderr,"Listen error:%s\n\a",strerror(errno));
exit(1);
}
printf("listen!\n");
printf("Accepting connections .......\n");
maxfd = lfd;
maxi = -1;
for(i = 0;i < FD_SETSIZE;i++)
{
client[i] = -1;
}
FD_ZERO(&allset);
FD_SET(lfd,&allset);
while(1)
{
rset = allset;
printf("selecting!\n");
rdy = select(maxfd + 1, &rset, NULL, NULL, NULL);
printf("selected!\n");
if(FD_ISSET(lfd, &rset))
{
addr_len = sizeof(sin);
printf("accepting!\n");
if((cfd=accept(lfd,(struct sockaddr *)(&cin),&addr_len))==-1)
{
fprintf(stderr,"Accept error:%s\n\a",strerror(errno));
exit(1);
}
printf("accepted!\n");
for(i = 0; i<FD_SETSIZE; i++)
{ //printf("%d\t",client[i]);
if(client[i] <= 0)
{
client[i] = cfd;
break;
}
}
if(i == FD_SETSIZE)
{
printf("too many clients");
exit(1);
}
FD_SET(cfd, &allset);
if(cfd > maxfd)
{
maxfd = cfd;
}
if(i > maxi)
{
maxi = i;
}
if(--rdy <= 0)
{
continue;
}
}
for(i = 0;i< FD_SETSIZE;i++)
{
if((sfd = client[i]) < 0)
{
continue;
}
if(FD_ISSET(sfd, &rset))
{
printf("reading!\n");
n = read(sfd,buffer,MAX_LINE);
printf("%s\n",buffer);
printf("read!\n");
if(n == 0)
{
printf("the other side has been closed. \n");
fflush(stdout);
close(sfd);
FD_CLR(sfd, &allset);
client[i] = -1;
}
else
{
inet_ntop(AF_INET, &cin.sin_addr, addr_p, sizeof(addr_p));
addr_p[strlen(addr_p)] = '\0';
printf("Client Ip is %s, port is %d\n",addr_p,ntohs(cin.sin_port));
if(n == 1)
{
exit(1);
}
}
if(--rdy <= 0)
{
break;
}
}
}
close(lfd);
return 0;
}
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define portnumber 8000
int main(int argc, char *argv[])
{
int nbytes;
int sockfd;
char buffer[80];
char buffer_2[80];
struct sockaddr_in server_addr;
struct hostent *host;
if(argc!=2)
{
fprintf(stderr,"Usage:%s hostname \a\n",argv[0]);
exit(1);
}
if((host=gethostbyname(argv[1]))==NULL)
{
fprintf(stderr,"Gethostname error\n");
exit(1);
}
if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1) // AF_INET:Internet;SOCK_STREAM:TCP
{
fprintf(stderr,"Socket Error:%s\a\n",strerror(errno));
exit(1);
}
bzero(&server_addr,sizeof(server_addr)); //
server_addr.sin_family=AF_INET;
server_addr.sin_port=htons(portnumber);
server_addr.sin_addr = *((struct in_addr *)host->h_addr);//址
if(connect(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
{
fprintf(stderr,"Connect Error:%s\a\n",strerror(errno));
exit(1);
}
while(1){
printf("Please input char:\n");
fgets(buffer,1024,stdin);
write(sockfd,buffer,strlen(buffer));
#if 0
if((nbytes=read(sockfd,buffer_2,81))==-1)
{
fprintf(stderr,"Read Error:%s\n",strerror(errno));
exit(1);
}
buffer_2[nbytes]='\0';
printf("Client received from Server %s\n",buffer_2);
#endif
}
close(sockfd);
exit(0);
}