1、UDP编程
服务端：
#include<stdio.h>
#include <arpa/inet.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
#include <pthread.h>
#include <strings.h>
#define QUIT_STR "QUIT"
#define SERV_PORT 5001
#define SERV_IP_ADDR "192.168.238.128"
#define bufsize 1024
int main()
{
int fd =-1;
//1.socket
fd = socket(AF_INET,SOCK_DGRAM,0);
if(fd ==-1)
{
perror("socket\n");
exit(1);
}
//2.addr
int b_reuser=1;
setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&b_reuser,sizeof(int));
//3.bind
struct sockaddr_in sin;
bzero(&sin,sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(SERV_PORT);
sin.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(fd,(struct sockaddr*)&sin,sizeof(sin))<0)
{
perror("bind");
exit(1);
}
char buf[bufsize];
//4.recvfrom
struct sockaddr_in cin;
socklen_t addrlen=sizeof(cin);
while(1)
{
bzero(buf,bufsize);
if(recvfrom(fd,buf,bufsize-1,0,(struct sockaddr*)&cin,&addrlen)<0)
{
perror("recvfrom\n");
continue;
}
char ipv4_addr[16];
if(!inet_ntop(AF_INET,(void*)&cin.sin_addr,ipv4_addr,sizeof(cin)))
{
perror("inet_ntop");
exit(1);
}
printf("recvive from (%s,%d),data:%s\n",ipv4_addr,ntohs(cin.sin_port),buf);
if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
{
printf("cilent:(%s,%d)\n",ipv4_addr,ntohs(cin.sin_port));
}
}
close(fd);
return 0;
}
客户端
#include<stdio.h>
#include <arpa/inet.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
#include <pthread.h>
#include <strings.h>
#define QUIT_STR "QUIT"
#define SERV_PORT 5001
#define SERV_IP_ADDR "192.168.238.128"
#define bufsize 1024
int main(int argc,char** argv)
{
if(argc!=3)
{
exit(1);
}
int port=-1;
port=atoi(argv[2]);
int fd =-1;
//1.socket
fd = socket(AF_INET,SOCK_DGRAM,0);
if(fd ==-1)
{
perror("socket\n");
exit(1);
}
struct sockaddr_in sin;
bzero(&sin,sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(port);
sin.sin_addr.s_addr = inet_addr(argv[1]);
char buf[bufsize];
//send
while(1)
{
bzero(buf,bufsize);
if(fgets(buf,bufsize-1,stdin) == NULL)
{
perror("fgets");
continue;
}
sendto(fd,buf,bufsize-1,0,(struct sockaddr*)&sin,sizeof(sin));
if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
{
perror("strncasecmp");
exit(1);
}
}
close(fd);
return 0;
}
运行结果：
2、IO多路复用
服务端：
#include<stdio.h>
#include <arpa/inet.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
#include <pthread.h>
#include <strings.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <unistd.h>
#define QUIT_STR "QUIT"
#define SERV_RESP_STR "SERVER:"
#define SERV_IP 5001
#define SERV_IP_ADDR "192.168.238.128"
#define bufsize 1024
void child_data_handle(int signum)
{
if(SIGCHLD==signum)
{
waitpid(-1,NULL,WNOHANG);
}
}
void* cilent_data_handle(void* arg)
{
int newfd=*(int *)arg;
char respbuf[bufsize];
char buf[bufsize];
printf("child process handle:newfd = %d\n",newfd);
int ret =-1;
while(1)
{
do
{
bzero(buf,bufsize);
ret=read(newfd,buf,bufsize-1);
}while(ret<1);
if(ret<0)
{
exit(1);
}
if(!ret)
{
break;
}
printf("recive data is %s\n",buf);
bzero(respbuf,bufsize-1);
strncpy(respbuf,SERV_RESP_STR,strlen(SERV_RESP_STR));
strcat(respbuf,buf);
do
{
ret =write(newfd,respbuf,strlen(respbuf));
}while(ret<0);
if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
{
printf("cilenr is exiting!\n");
break;
}
}
close(newfd);
}
int main()
{
int fd=-1;
signal(SIGCHLD,child_data_handle);
fd=socket(AF_INET,SOCK_STREAM,0);
if(fd == -1)
{
perror("socket");
exit(1);
}
struct sockaddr_in sin;
bzero(&sin,sizeof(sin));
sin.sin_family=AF_INET;
sin.sin_port = htons(SERV_IP);
sin.sin_addr.s_addr = INADDR_ANY;
/* if(inet_pton(AF_INET,SERV_IP_ADDR,(void*)&sin.sin_addr.s_addr)!=1)
{
perror("inet_pton");
exit(1);
}
*/
//2.bind
if(bind(fd,(struct sockaddr *)&sin,sizeof(sin))<0)
{
perror("bind");
exit(1);
}
//3.listen
if(listen(fd,5)<0)
{
perror("listen");
exit(1);
}
//4.accep
int newfd=-1;
pthread_t tid;
pid_t pid;
struct sockaddr_in cin;
socklen_t addrlen=sizeof(cin);
while(1)
{
newfd= accept(fd,(struct sockaddr*)&cin,&addrlen);
if(newfd<0)
{
perror("accept");
exit(1);
}
pid = fork();
if(pid<0)
{
perror("fork");
break;
}
if(pid == 0)
{
char IPV4_addr[16];
if(!inet_ntop(AF_INET,(void *)&cin.sin_addr,IPV4_addr,sizeof(cin)))
{
perror("inet_ntop");
exit(1);
}
printf("cilent:(%s,%d)is connect\n",IPV4_addr,ntohs(cin.sin_port));
cilent_data_handle(&newfd);
close(fd);
}
if(pid >0)
{
close(newfd);
}
}
//read
return 0;
}
客户端：
#include<stdio.h>
#include <arpa/inet.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
#include <pthread.h>
#include <strings.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#define SERV_RESP_STR "SERVER:"
#define QUIT_STR "QUIT"
#define SERV_PORT 5001
#define SERV_IP_ADDR "192.168.238.128"
#define bufsize 1024
int main(int argc,char** argv)
{
if(argc!=3)
{
exit(1);
}
int port=-1;
port=atoi(argv[2]);
int fd =-1;
//1.socket
fd = socket(AF_INET,SOCK_STREAM,0);
if(fd ==-1)
{
perror("socket\n");
exit(1);
}
struct sockaddr_in sin;
bzero(&sin,sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(port);
sin.sin_addr.s_addr = inet_addr(argv[1]);
if(connect(fd,(struct sockaddr*)&sin,sizeof(sin))<0)
{
perror("connect");
exit(1);
}
fd_set rset;
int maxfd =-1;
char buf[bufsize];
int ret =-1;
struct timeval tout;
while(1)
{
FD_ZERO(&rset);
FD_SET(0,&rset);
FD_SET(fd,&rset);
maxfd = fd;
tout.tv_sec = 5;
tout.tv_usec = 0;
select(maxfd+1,&rset,NULL,NULL,&tout);
if(FD_ISSET(0,&rset))
{
bzero(buf,bufsize);
do
{
ret = read(0,buf,bufsize-1);
}while(ret<0);
if(ret<0)
{
perror("read");
continue;
}
if(!ret)
{
continue;
}
if(write(fd,buf,strlen(buf))<0)
{
perror("write");
continue;
}
if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
{
printf("cilent is exited!\n");
break;
}
}
if(FD_ISSET(fd,&rset))
{
bzero(buf,bufsize);
do
{
ret = read(fd,buf,bufsize-1);
}while(ret<0);
if(ret<0)
{
perror("read");
continue;
}
if(!ret)
{
break;
}
printf("service said:%s\n",buf);
if((strlen(buf)>strlen(SERV_RESP_STR)) && (!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR))))
{
printf("cilent is exited!\n");
break;
}
}
}
/* char buf[bufsize];
//send
while(1)
{
bzero(buf,bufsize);
if(fgets(buf,bufsize-1,stdin) == NULL)
{
perror("fgets");
continue;
}
sendto(fd,buf,bufsize-1,0,(struct sockaddr*)&sin,sizeof(sin));
if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
{
perror("strncasecmp");
exit(1);
}
}*/
close(fd);
return 0;
}运行结果：
