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一、多进程实现并发服务器
代码如下：multiprocess_server.c
/*
============================================================================
Name : TCPServer.c
Author : jiangyu
Version :
date : 2018-10-8
Description : Simple Socket Server
============================================================================
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <signal.h>
#define MYPORT 8080
int main( int argc , char ** argv )
{
signal(SIGCHLD,SIG_IGN);//把子进程的僵尸进程给init进程处理
struct sockaddr_in saddr, caddr;
char send_buf[1024];
char recv_buf[1024];
char ipbuf[50];
int sockfd, connfd;
int addr_len;
pid_t pid;
sockfd = socket( AF_INET, SOCK_STREAM, 0 );
memset(&saddr, 0, sizeof(saddr) );
memset( send_buf, 0, sizeof(send_buf) );
memset( recv_buf, 0, sizeof(recv_buf) );
memset( ipbuf, 0, sizeof(ipbuf) );
saddr.sin_family = AF_INET;
saddr.sin_port = htons(MYPORT);
saddr.sin_addr.s_addr = htonl( INADDR_ANY ); //any address
bind( sockfd, (struct sockaddr *)&saddr, 16 );
listen( sockfd, 20 );
printf( "Accepting connections ... \n" );
int n;
addr_len = sizeof( caddr );
//循环接收 客户端的连入
while(1)
{
if((connfd = accept( sockfd, (struct sockaddr*)&caddr, &addr_len ))>0)
{
printf("new client connect successful!\n");
}
//打印新接入客户端IP、端口
inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50); //地址格式转换为数值格式
printf("the client:%s is in\n",ipbuf);
//创建一个子进程来接受新客户端的信息
pid = fork();
if(pid<0) //fork失败
{
perror("failed fork()");
return -1;
}
else if(pid == 0) //子进程
{
close(sockfd);//关闭从父进程进程来的监听套接字，因为在子进程用不到，关闭不需要的套接字可节省系统资源，同时可避免父子进程共享这些套接字可能带来的不可预计的后果
//这个子进程循环接收客户端信息
while(1)
{
n = recv( connfd, recv_buf, sizeof(recv_buf), 0 );
if(n<0)
{
perror("failed recv");
}
else if(n == 0)
{
bzero(ipbuf,50);
inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50);
printf("the client:%s is out\n",ipbuf);
exit(0);
close(connfd);
}
else{
//子进程处理
inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50);
printf("ip:%s,port:%d\n",ipbuf,ntohs(caddr.sin_port));
printf("Recived %d bytes\n",n);
int i;
for(i=0;i<n;i++)
{
printf("%02x\n", recv_buf[i]);
}
//printf("Recived %d bytes: %s \n",n, recv_buf);
send(connfd,recv_buf,n,0);
memset( recv_buf, 0, sizeof(recv_buf) );
}
}
}
else if(pid>0) //父进程，用于继续监测有没有新的客户端连入
{
close(connfd);//关闭新客户端返回的套接字，因为在父进程中用不到
continue;
}
/*
printf("please input:\n");
gets(send_buf);
send(connfd,send_buf,strlen(send_buf),0);
printf("send :%s\n",send_buf);
memset( send_buf, 0, sizeof(send_buf) );
n = recv( connfd, recv_buf, sizeof(recv_buf), 0 );
if(n>0)
{
printf("Recived %d bytes: %s \n",n, recv_buf);
send(connfd,recv_buf,n,0);
memset( recv_buf, 0, sizeof(recv_buf) );
}
*/
}
close( sockfd );
close( connfd );
return -1;
}
二、多线程实现并发服务器
代码如下：multipthread_server.c
/*
============================================================================
Name : multipthread_server.c
Author : Greein-jy
Version : v1.0
date : 2018-10-10
Description : Multipthread Socket Server
============================================================================
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>
#include <signal.h>
#include <sys/select.h>
#define MYPORT 8080
#define REQ_FRAME_SIZE 9 //传感器信息协议帧总长
//传感器数据请求格式
#define HEAD 0xAA
#define LEN 0x09
#define OPTION 0x00
#define CMD 0X01
#define DATA1 0x0f //数据域，表示需要请求哪些数据
#define DATA2 0xff //数据域，表示需要请求哪些数据
#define TAIL 0x55
unsigned short CRC_Compute(unsigned char*,unsigned char);
int sockfd, new_sock;
char req_buf[REQ_FRAME_SIZE] = {0};
unsigned char ipbuf[50];
struct sockaddr_in saddr, caddr;
//请求帧构造函数
void req_data_frame()
{
req_buf[0]=HEAD;
req_buf[1]=LEN;
req_buf[2]=OPTION;
req_buf[3]=CMD;
req_buf[4]=DATA1;
req_buf[5]=DATA2;
unsigned short crc16 = CRC_Compute(req_buf,(unsigned char)6);
req_buf[6] = (char)crc16;
req_buf[7] = (char)(crc16>>8);
req_buf[8]=TAIL;
}
//线程处理函数
void* pthread_handler(void* sock)
{
unsigned char recv_buf[1024] = {0};
int newsock = *((int*)sock);
int n;
req_data_frame();
while(1)
{
fd_set fds; //定义文件描述符集
struct timeval timeout;
timeout.tv_sec = 10; //设置超时时间为10s
timeout.tv_usec = 0;
FD_ZERO(&fds);//清除文件描述符集
FD_SET(newsock, &fds);//将文件描述符加入文件描述符集中；
//发送数据请求
send(newsock,req_buf,REQ_FRAME_SIZE,0);
printf("send req success!\n");
if(select(newsock+1,&fds,NULL,NULL,&timeout) > 0 ) //监听socket，超时时间为10s
{
printf("start to receive data...\n");
//接收数据，处理数据
n = recv( newsock, recv_buf, REQ_FRAME_SIZE, 0 );
if(n<0)
{
perror("failed recv");
}
else if(n == 0)
{
memset( ipbuf, 0, sizeof(ipbuf) );
inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50);
printf("the client:%s is quit\n",ipbuf);
close(newsock);
break;
}
else
{
printf("ip:%s,port:%d\n",ipbuf,ntohs(caddr.sin_port));
printf("Recived %d bytes\n",n);
int i;
for(i=0;i<n;i++)
{
printf("%02x", recv_buf[i]);
}
printf("\n");
printf("Recived %d bytes: %s \n",n, recv_buf);
//send(newsock,recv_buf,n,0);
memset( recv_buf, 0, sizeof(recv_buf) );
}
sleep(5); //延时5s，每5s发送一次数据请求
}
}
close(newsock);
}
int main( int argc , char ** argv )
{
int addr_len;
pid_t pid;
sockfd = socket( AF_INET, SOCK_STREAM, 0 );
memset(&saddr, 0, sizeof(saddr) );
memset( ipbuf, 0, sizeof(ipbuf) );
saddr.sin_family = AF_INET;
saddr.sin_port = htons(MYPORT);
saddr.sin_addr.s_addr = htonl( INADDR_ANY ); //any address
bind( sockfd, (struct sockaddr *)&saddr, 16 );
listen( sockfd, 20 );
printf( "Accepting connections ... \n" );
addr_len = sizeof( caddr );
//循环接收 客户端的连入
while(1)
{
if((new_sock = accept( sockfd, (struct sockaddr*)&caddr, &addr_len ))>0)
{
printf("new client connect successful!\n");
//打印新接入客户端IP、端口
inet_ntop(AF_INET,(void*)&caddr.sin_addr.s_addr,ipbuf,50); //地址格式转换为数值格式
printf("the client:%s is in\n",ipbuf);
}
//创建一个线程来接收新客户端的信息
pthread_t id;
pthread_create(&id,NULL,pthread_handler,(void*)&new_sock);
/*pthread有两种状态:joinable状态和unjoinable状态
一个线程默认的状态是joinable，如果线程是joinable状态，当线程函数自己返回退出时或pthread_exit时都不会释放线程所占用堆栈和线程描述符（总计8K多）。只有当你调用了pthread_join之后这些资源才会被释放。
若是unjoinable状态的线程，这些资源在线程函数退出时或pthread_exit时自动会被释放。
unjoinable属性可以在pthread_create时指定，或在线程创建后在线程中pthread_detach自己, 如：pthread_detach(当前线程ID)，将状态改为unjoinable状态，确保资源的释放。如果线程状态为 joinable,需要在之后适时调用pthread_join.
*/
pthread_detach(id);
}
close( sockfd );
return 0;
}
//CRC校验函数
unsigned short CRC_Compute(unsigned char* snd,unsigned char len)
{
auto int i, j;
auto unsigned short c,crc=0xFFFF;
for(i = 0;i < len; i ++)
{
c = snd[i] & 0x00FF;
crc ^= c;
for(j = 0;j < 8; j ++)
{
if (crc & 0x0001)
{
crc>>=1;
crc^=0xA001;
}else crc>>=1;
}
}
return (crc);
}