[网络协议]TCP服务器demo

TCP服务器demo

基于TCP服务器， fork多进程并发服务器

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/signal.h>
#include <sys/wait.h>

#define BUF_SIZE 256
#define HOST_PORT 65423
#define LISTEN_SIZE 4

//信号灯集处理函数（子进程退出时触发）
void signal_hander(int sig)
{
	waitpid(-1, NULL, WNOHANG);
}


int main(int argc, const char *argv[])
{
	//打印服务器主机端口
	printf("HOST_PORT is %d\n", HOST_PORT);
	//	printf("HOST_IP is %d\n", htonl(INADDR_ANY));

	//信号灯集注册
	if(signal(SIGCHLD, signal_hander) == SIG_ERR)
	{
		perror("Signal");
		return -1;
	}

	//创建接受和发送字符串数组	
	char recvbuf[BUF_SIZE] = {0};
	char sendbuf[BUF_SIZE] = {0};
	int sendbuf_size = sizeof(sendbuf);
	int recvbuf_size = sizeof(recvbuf);

	//创建网络地址结构体
	struct sockaddr_in serveraddr, clientaddr;
	int serveraddr_size = sizeof(serveraddr);
	int clientaddr_size = sizeof(clientaddr);
	memset(&serveraddr, 0, serveraddr_size);
	memset(&clientaddr, 0, clientaddr_size);

	//创建socket连接
	int sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd == -1)
	{
		perror("Socket");
		return -1;
	}

	//允许端口复用
	socklen_t enble_reuseAddr = 1;
	int ret = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &enble_reuseAddr, sizeof(enble_reuseAddr));
	if(ret == -1)
	{
		perror("Setsockopt");
		close(sockfd);
		return -1;
	}

	//配置服务器主机端口和ip
	serveraddr.sin_family = AF_INET;//地址族
	serveraddr.sin_port = htons(HOST_PORT);//端口号
	serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);//本机ip

	//绑定端口和ip
	int rebind = bind(sockfd, (struct sockaddr*)&serveraddr, serveraddr_size);
	if(rebind == -1)
	{
		perror("Bind");
		close(sockfd);
		return -1;
	}

	//监听客户端连接请求
	int relisten = listen(sockfd, LISTEN_SIZE);
	if(relisten == -1)
	{
		perror("Listen");
		close(sockfd);
		return -1;
	}

	//业务处理
	while(1)
	{
		printf("Waiting for client connection ....\n");

		//建立连接
		int connectfd = accept(sockfd, (struct sockaddr*)&clientaddr, &clientaddr_size);
		if(connectfd == -1)
		{
			perror("Accept");
			close(sockfd);
			return -1;
		}
		printf("\nClient connection succeeded ....\n");
		printf("Client ip is    : %s\n", inet_ntoa(clientaddr.sin_addr));
		printf("Client port is  : %d\n", ntohs(clientaddr.sin_port));

		//创建进程
		pid_t pid = fork();
		switch(pid)
		{
		case -1://创建进程错误
			{
				perror("Fock");
				close(sockfd);
				close(connectfd);
				exit(-1);
				break;
			}
		case 0://子进程
			{
				close(sockfd);
				while(1)
				{
					memset(recvbuf, 0, recvbuf_size);
					memset(sendbuf, 0, sendbuf_size);

					//接收客户端消息存入recvbuf
					int recv_len = recv(connectfd, recvbuf, recvbuf_size, 0);
					if(recv_len == -1)
					{
						perror("Recv");
						close(connectfd);
						exit(-1);
					}else if(recv_len == 0)
					{
						printf("Client disconnect IP: %s Port: %d\n", inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));
						close(connectfd);
						exit(0);
					}

					puts(recvbuf);
					//用户数据处理函数

					strcpy(sendbuf, recvbuf);
					//把sendbuf内容发送至客户端
					send(connectfd, sendbuf, strlen(sendbuf), 0);
				}
				close(connectfd);
				//				exit(0);
				break;
			}
		default://主进程
			{
				continue;
			}
		}
	}
	close(sockfd);//关闭套接字
	return 0;
}