linux网络编程多进程并发服务器

服务器端：

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

#define PORT 				1234
#define MAXSIZE				1024

static int clientProcess(int connfd, struct sockaddr_in clientSock)
{
	int num = 0;
	int i = 0;
	char recvBuf[MAXSIZE];
	char sendBuf[MAXSIZE];
	char clientName[MAXSIZE];

	num = recv(connfd, clientName, MAXSIZE, 0);
	if (num < 0)
	{
		printf("recv clientName message from client!\n");
		return -1;
	}
	clientName[strlen(clientName)-1] = '\0';
	printf("You got's a connection from %s, client name is %s\n",
		inet_ntoa(clientSock.sin_addr), clientName);

	while (1)
	{
		num = recv(connfd, recvBuf, MAXSIZE, 0);
		if (num == 0)
		{
			close(connfd);
			return -1;
		}
		recvBuf[strlen(recvBuf)-1] = '\0';
		printf("received client (%s) message :%s\n", clientName, recvBuf);

		//将接收到的信息加密返回给客户端
		for (i=0; i<num-1; i++)
		{
			if ((recvBuf[i]>='a' && recvBuf[i]<='z') || (recvBuf[i]>='A' && recvBuf[i]<='Z'))
			{
				recvBuf[i] = recvBuf[i] + 3;
				if ((recvBuf[i]>'Z' && recvBuf[i]<'Z'+3) || (recvBuf[i]>'z'))
				{
					recvBuf[i] = recvBuf[i] -26;
				}
			}
			sendBuf[i] = recvBuf[i];
		}
		sendBuf[num-1] = '\0';

		send(connfd, sendBuf, MAXSIZE, 0);
	}

	close(connfd);

	return 1;
}

int main(int argc, char **argv)
{
	int listenfd;
	int connectfd;
	struct sockaddr_in serverSock;
	struct sockaddr_in clientSock;
	socklen_t len = 0;
	pid_t pid;

	listenfd = socket(AF_INET, SOCK_STREAM, 0);
	if (listenfd < 0)
	{
		printf("Create socket fails!\n");
		return -1;
	}

	int opt = SO_REUSEADDR;
	setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof opt);

	bzero(&serverSock, sizeof serverSock);
	serverSock.sin_family = AF_INET;
	serverSock.sin_port = htons(PORT);
	serverSock.sin_addr.s_addr = htonl(INADDR_ANY);

	if (bind(listenfd, (struct sockaddr *)&serverSock, sizeof serverSock) < 0)
	{
		printf("bind fails!\n");
		return -1;
	}

	if (listen(listenfd, 5) < 0)
	{
		printf("listen fails!\n");
		return -1;
	}

	len = (socklen_t)(sizeof clientSock);

	while (1)
	{
		connectfd = accept(listenfd, (struct sockaddr *)&clientSock, &len);
		if (connectfd < 0)
		{
			printf("accept fails!\n");
			return -1;
		}

		//创建子进程处理客户端的信息
		if ((pid = fork()) > 0)
		{
			close(connectfd);
			continue;
		}
		else if (pid == 0)
		{
			close(listenfd);
			clientProcess(connectfd, clientSock);
			return 1;
		}
		else
		{
			printf("fork() fails!\n");
			return -1;
		}
	}

	close(listenfd);
}

客户端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#define PORT				1234
#define MAXSIZE 				1024

static int clientProcess(FILE *fp, int connfd)
{
	char readLine[MAXSIZE];
	char recvLine[MAXSIZE];
	int num;

	printf("connect to server success!\n");
	printf("Input client's name:");
	if (fgets(readLine, MAXSIZE, fp) == NULL)
	{
		printf("fgets fails!\n");
		return -1;
	}

	send(connfd, readLine, MAXSIZE, 0);

	while (fgets(readLine, MAXSIZE, fp) != NULL)
	{
		if (strncmp(readLine, "quit", strlen("quit")) == 0)
		{
			exit(-1);
		}
		send(connfd, readLine, strlen(readLine), 0);

		num = recv(connfd, recvLine, MAXSIZE, 0);
		if (num < 0)
		{
			printf("received fails!\n");
			return -1;
		}
		recvLine[num-1] = '\0';

		printf("Server message:%s\n", recvLine);
	}

	return 1;
}

int main(int argc, char **argv)
{
	int sockfd;
	struct sockaddr_in serverSock;
	struct hostent *he;

	if (argc != 2)
	{
		printf("Usage: %s <IP Address>\n", argv[0]);
		return -1;
	}

	he = gethostbyname(argv[1]);
	if (he == NULL)
	{
		printf("gethostbyname fails!\n");
		return -1;
	}

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0)
	{
		printf("Create socket fails!\n");
		return -1;
	}

	bzero(&serverSock, sizeof serverSock);
	serverSock.sin_family = AF_INET;
	serverSock.sin_port = htons(PORT);
	serverSock.sin_addr = *((struct in_addr *)he->h_addr);

	if (connect(sockfd, (struct sockaddr *)&serverSock, sizeof serverSock) < 0)
	{
		printf("connect fails!\n");
		return -1;
	}

	clientProcess(stdin, sockfd);

	close(sockfd);
	return 1;
}

程序实现的功能很简单，代码写的也比较通俗易懂，基本上没什么注释！代码在我自己的虚拟机里面调试通过，编译即可运行！