嵌入式Linux网络编程，I/O多路复用，select()示例，select()客户端，select()服务器，单链表

其他 2018-12-14 18:48:33 阅读次数: 0

文章目录

1，IO复用select()示例

1.1 select()—net.h

#ifndef __NET_H__
#define __NET_H__

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/select.h>

#define SERV_IP_ADDR "192.168.31.100"
#define SERV_PORT 5002
#define BACKLOG 5
#define QUIT_STR "quite"
#define SERV_RESP_STR "Server:"

#endif

1.2 select()—client.c

/* ./client serv_ip serv_port */
#include "net.h"

void usage(char *s)
{
	printf("Usage: %s <serv_ip> <serv_port>\n",s);
	printf("\tserv_ip: server ip address\n");
	printf("\tserv_port: server port(>5000)\n ");
}
int main(int argc, const char *argv[])
{
	int fd;
	short port;
	struct sockaddr_in sin;
	if(argc != 3)
	{
		usage((char *)argv[0]);
		exit(1);
	}
	if((port = atoi(argv[2])) < 5000)
	{
		usage((char *)argv[0]);
		exit(1);
	}
	/* 1 创建socket fd */
	if((fd = socket(AF_INET,SOCK_STREAM,0)) < 0)
	{
		perror("socket");
		exit(-1);
	}
	
	/* 2 连接服务器 */
	/* 2.1 填充struct sockaddr_in结构体变量*/
	bzero(&sin,sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons(port);//转为网络字节序端口号
	if(inet_pton(AF_INET,argv[1],(void *)&sin.sin_addr.s_addr) < 0)
	{
		perror("inet_pton");
		goto _error1;
	}

	/* 2.2 连接服务器*/
	if(connect(fd,(struct sockaddr *)&sin,sizeof(sin)) < 0)
	{
		perror("connect");
		goto _error1;
	}
	printf("client staring ... OK!\n");

	fd_set rset;
	int maxfd;
	struct timeval tout;
	char buf[BUFSIZ];
	int ret = -1;
	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))//标准输入里面是不是有输入
		{
			/* 读取键盘输入，发送到网络套接字fd */
			bzero(buf,BUFSIZ);
			do 
			{
				ret = read(0,buf,BUFSIZ-1);
			}while(ret <0 && EINTR == errno);
			if(ret < 0)
			{
				perror("read");
				continue ;
			}
			if(ret == 0)//没读到数据
			{
				continue;
			}
			if(write(fd,buf,strlen(buf)) < 0)
			{
				perror("write() to socket");
				continue ;
			}
			if(strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)) == 0)//退出在发送之后
			{
				printf("client is existing!\n");
				break;
			}
		}
		if(FD_ISSET(fd,&rset))//服务器发送了数据过来
		{
			/* 读取套接字数据，处理 */
			bzero(buf,BUFSIZ);
			do 
			{
				ret = read(fd,buf,BUFSIZ-1);
			}while(ret <0 && EINTR == errno);
			if(ret < 0)
			{
				perror("read from socket");
				continue ;
			}
			if(ret == 0)//从套接字中读到的数据个数小于0，说明服务器关闭
			{
				break ;
			}
			printf("server said: %s",buf);
			if((strlen(buf) > strlen(SERV_RESP_STR)) && strncasecmp(buf+strlen(SERV_RESP_STR),QUIT_STR,strlen(QUIT_STR)) == 0)
			{
				printf("sender client is existing!\n");
				break;
			}

		}
	}

_error1:
	close(fd);
	return 0;
}

1.3 select()—sever.c

#include "net.h"
#include "linklist.h"
#include <sys/ioctl.h>

/* IO多路复用select()处理函数 */
void do_select(int fd);

int main(int argc, const char *argv[])
{
	int fd;
	struct sockaddr_in sin;//如果是IPV6的编程，要使用struct sockddr_in6结构体（详细情况请参考man 7 ipv6）,通常更通用的方法可以通过struct sockaddr_storage来编程

	/* 1 创建socket fd */
	if((fd = socket(AF_INET,SOCK_STREAM,0)) < 0)
	{
		perror("socket");
		exit(-1);
	}
	/* 优化 1 允许绑定地址快速重用 */ 
	int b_reuse = 1;
	setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&b_reuse,sizeof(int)); 
	
	/* 2 绑定 */
	/* 2.1 填充struct sockaddr_in 结构体变量*/
	bzero(&sin,sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons(SERV_PORT);
#if 1
	/* 优化 2 让服务器可以绑定在任意的IP上*/
	sin.sin_addr.s_addr = htonl(INADDR_ANY);
#else
	if(inet_pton(AF_INET,SERV_IP_ADDR,(void *)&sin.sin_addr.s_addr) < 0)
	{
		perror("inet_pton");
		goto _error1;
	}
#endif
	/* 2.2 绑定*/
	if(bind(fd,(struct sockaddr *)&sin,sizeof(sin)))
	{
		perror("bind");
		goto _error1;
	}

	/* 3 使用listen()把主动套接字变成被动套接字 */
	if(listen(fd,BACKLOG) < 0)
	{
		perror("listen");
		goto _error1;
	}
	
	do_select(fd);

_error1:
	close(fd);
	return 0;
}

void do_select(int fd)
{
	linklist fdlist,sin_list;//创建一个列表，用于文件描述符及客户端信息存储
	fdlist = create_linklist();
	datatype sin_data;//每个对象包括客户端的socket fd,ipv4地址，端口号
	sin_data.fd = fd;
	int maxfd = fd;
	//struct timeval tout = {5,0};

	insert_end_linklist(fdlist,sin_data);//将lsten()处理后的fd加入列表
	//show_linklist(fdlist);
	
	fd_set rset;
	int newfd = -1;
	int ret = -1;
	char buf[BUFSIZ];//BUFSIZ是系统提供的
	char resp_buf[BUFSIZ+10];
	struct sockaddr_in cin;
	socklen_t cin_addr_len = sizeof(cin);
	/* 用select()函数实现I/O多路复用*/
	while(1)
	{
		int i;
		FD_ZERO(&rset);
		if(get_length_linklist(fdlist) >= 1)//将列表中的fd加入读集合进行处理
		{
				//puts("11111111111111111111111111111");
			for(i=0;i<get_length_linklist(fdlist);i++)
			{
				sin_list = get_list_pos_linklist(fdlist,i);
				sin_data = sin_list->data;
				FD_SET(sin_data.fd,&rset);
				maxfd = sin_data.fd > maxfd ? sin_data.fd : maxfd;
				//printf("第 %d 个（fd:%d）（ip:%s）（port:%d）\n",i,sin_data.fd,sin_data.ipv4_addr,sin_data.port);
			}
			//show_linklist(fdlist);
		}
		else
		{
			continue ;
		}
		//switch(select(maxfd+1,&rset,NULL,NULL,&tout))
		switch(select(maxfd+1,&rset,NULL,NULL,NULL))
		{
			case 0:
			{
				printf("time out!\n");
				goto _error1;
			}
			case -1:
			{
				perror("select");
				goto _error1;
			}
			default:
			{
				if(FD_ISSET(fd,&rset))//有客户端发送了连接请求
				{
					if((newfd = accept(fd,(struct sockaddr *)&cin,&cin_addr_len)) < 0)
					{
						perror("connect");
						goto _error1;
					}
					/* 将分配成功的套接字newfd设置成非阻塞模式*/
					int b_on = 1;
   					ioctl(newfd, FIONBIO, &b_on);//将分配成功的套接字newfd设置为非阻塞方式
					sin_data.fd = newfd;
					if(inet_ntop(AF_INET,&cin.sin_addr.s_addr,sin_data.ipv4_addr,sizeof(sin_data.ipv4_addr)) < 0)
					{
						perror("inet_ntop");
						goto _error2;
					}
					sin_data.port = ntohs(cin.sin_port);
					printf("get a new client->(ip:%s)(port:%d)(fd:%d)\n",sin_data.ipv4_addr,sin_data.port,sin_data.fd);
					
					insert_end_linklist(fdlist,sin_data);//将建立客户端连接的fd加入列表
					//show_linklist(fdlist);
				}
				else//有连接好的客户端发送了数据
				{
					//puts("22222222222222222222");
					for(i=0;i<get_length_linklist(fdlist);i++)//将链表中的fd都处理一遍
					{
						
						sin_list = get_list_pos_linklist(fdlist,i);
						sin_data = sin_list->data;
						//printf("reading fd is ->(第 %d 个)(fd:%d)(ip:%s)(port:%d)\n",i,sin_data.fd,sin_data.ipv4_addr,sin_data.port);
						if(sin_data.fd == fd)//不是建立连接后分配的newfd
							continue ;
						//puts("########read before");
						bzero(buf,BUFSIZ);
						do
						{
							ret = read(sin_data.fd,buf,BUFSIZ-1);
						}while(ret < 0 && errno == EINTR);//阻塞读写
						
						if(ret < 0)
						{
							//perror("read");
							continue;
						}
						if(ret == 0)//对方已关闭
						{
							printf("client is existing!\n");
							delete_locate_linklist(fdlist,sin_data);
							continue;
						}

						printf("client ip(:%s) port(:%d) fd(:%d) receive data: %s",sin_data.ipv4_addr,sin_data.port,sin_data.fd,buf);
					
						bzero(resp_buf,BUFSIZ+25);
						strncpy(resp_buf,SERV_RESP_STR,strlen(SERV_RESP_STR));
						strcat(resp_buf,"ip(");
						strcat(resp_buf,sin_data.ipv4_addr);
						char s_port[10];
						strcat(resp_buf,"  port(");
						sprintf(s_port,"%d",sin_data.port);
						strcat(resp_buf,s_port);
						strcat(resp_buf,"  data(");
						strcat(resp_buf,buf);
						do
						{
							ret = write(sin_data.fd,resp_buf,strlen(resp_buf));
						}while(ret < 0 && EINTR == errno);
						//puts("###############################");	
						if(strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)) == 0)
						{
							printf("client (fd:%d)(ip:%s)(potr:%d) is existing!\n",sin_data.fd,sin_data.ipv4_addr,sin_data.port);
							delete_locate_linklist(fdlist,sin_data);//将退出的客户端的fd从列表中删除
							close(sin_data.fd);
							//show_linklist(fdlist);
						}
					}
				}		
			}
		}
	}

_error2:
	close(newfd);
_error1:
	close(fd);
	clear_linklist(fdlist);

}

1.4 select()—linklist.h

#ifndef __SINGLE_LINKLIST_H__
#define __SINGLE_LINKLIST_H__

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

typedef struct{
	int fd;
	char ipv4_addr[16];
	int port;
}datatype;

typedef struct node{
	datatype data;
	struct node *next;
}listnode,*linklist;

linklist create_linklist(void);
linklist create_n_linklist(void);
int delete_pos_linklist(linklist L,int pos);
int delete_locate_linklist(linklist L,datatype x);
void clear_linklist(linklist L);

int get_length_linklist(linklist L);
linklist get_list_pos_linklist(linklist L,int pos);
linklist get_list_locate_linklist(linklist L,datatype x);

int insert_head_linklist(linklist L,datatype x);
int insert_n_head_linklist(linklist L);
int insert_end_linklist(linklist L,datatype x);
int insert_n_end_linklist(linklist L);
int insert_pos_linklist(linklist L,datatype x,int pos);
int insert_order_linklist(linklist L,datatype x);

void reverse_linklist(linklist);
void sort_linklist(linklist L);

void show_linklist(linklist L);

#endif

1.5 select()—linklist.c

#include "linklist.h"


linklist create_linklist(void)
{
	linklist L;
	if((L=(linklist)malloc(sizeof(listnode))) == NULL)
	{
		printf("malloc no memmory!\n");
		return NULL;
	}
	L->data.fd = 0;
	bzero(L->data.ipv4_addr,sizeof(L->data.ipv4_addr));
	L->data.port = 0;

	L->next = NULL;
	return L;
}
linklist create_n_linklist(void)
{
	linklist L,H,r;
	datatype x;
	if((L=(linklist)malloc(sizeof(listnode))) == NULL)
	{
		printf("malloc no memmory!\n");
		return NULL;
	}
	L->data.fd = 0;
	bzero(L->data.ipv4_addr,sizeof(L->data.ipv4_addr));
	L->data.port = 0;
	L->next = NULL;
	r = L;
	while(1)
	{
		printf("Please input a NUM_NL80211_WOWLAN_TRIGber(-1 exit :");
		while(scanf("%d",&x.fd) != 1)
		{
			printf("Please INPUT_PROP_CNTut a number(-1 exit :");
			getchar();
		}

		if(x.fd == -1)break;

		if((H=(linklist)malloc(sizeof(listnode))) == NULL)
		{
			printf("malloc nexto memmory!\n");
			return L;
		}
		H->data = x;
		H->next = NULL;
		r->next = H;
		r=H;
	}
	return L;

}
int delete_pos_linklist(linklist L,int pos)
{
	linklist r,p;
	int i=-1;
	if(pos < 0 ||pos >=get_length_linklist(L))
	{
		printf("input pos is invalid!\n");
		return -1;
	}
	r = L;
	while(i < pos-1)
	{
		i++;
		r = r->next;
	}
	if(r == NULL || r->next==NULL)
	{
		printf("argc is iavalid!\n");
		return -1;
	}
	else
	{
		p = r->next;
		r->next = p->next;
		p->next = NULL;
		free(p);
		return 0;
	}
}
int delete_locate_linklist(linklist L,datatype x)
{
	linklist r,p;
	if(L->next == NULL)
	{
		printf("list is NULL!\n");
		return -1;
	}
	r = L;
	while(r->next->data.fd != x.fd)
	{
		if(r->next == NULL)
		{
			printf("value is not in list!\n");
			return -1;
		}
		r = r->next;
	}
	p = r->next;
	r->next = p->next;
	p->next = NULL;
	free(p);

	return 0;
}

void clear_linklist(linklist L)
{
	while(get_length_linklist(L))
	{
		delete_pos_linklist(L,get_length_linklist(L)-1);
	}
	free(L);
	L->next = NULL;
	L = NULL;
}
int get_length_linklist(linklist L)
{
	int i=0;
	linklist r;
	r = L;
	while(r->next)
	{
		r = r->next;
		i++;
	}
	return i++;
}
linklist get_list_pos_linklist(linklist L,int pos)
{
	int i=0;
	linklist r;
	if(L->next == NULL)
	{
		printf("list is NULL!\n");
		return NULL;
	}
	if(pos<0 || pos>=get_length_linklist(L))
	{
		printf("input is invalid!\n");
		return NULL;
	}
	r = L->next;
	while(i<pos)
	{
		r = r->next;
		i++;
	}
	return r;
}
linklist get_list_locate_linklist(linklist L,datatype x)
{
	linklist r;
	if(L->next == NULL)
	{
		printf("list is NULL!\n");
		return NULL;
	}
	r = L->next;
	while(r->data.fd != x.fd)
	{
		if(r->next == NULL)
		{
			printf("value is not in list!\n");
			return NULL;
		}
		r = r->next;
	}
	return r;
}

int insert_head_linklist(linklist L,datatype x)
{
	linklist H;
	if((H=(linklist)malloc(sizeof(listnode))) == NULL)
	{
		printf("malloc no memmory\n");
		return -1;
	}
	H->data = x;
	H->next = L->next;
	L->next = H;
	return 0;
}
int insert_n_head_linklist(linklist L)
{
	datatype x;

	while(1)
	{
		printf("Please input a number(-1 exit:");
		while(scanf("%d",&x.fd) != 1)
		{
			printf("Please input a number:(-1 exit");
			getchar();
		}
		if(x.fd == -1)break;
		insert_head_linklist(L,x);
	}
	return 0;
}
int insert_end_linklist(linklist L,datatype x)
{
	linklist r,H;
	if((H = (linklist)malloc(sizeof(listnode))) == NULL)
	{
		printf("malloc no memmory!");
		return -1;
	}
	r = L;
	while(r->next)
	{
		r = r->next;
	}
	H->next = NULL;
	H->data = x;
	r->next = H;
	return 0;
}
int insert_n_end_linklist(linklist L)
{
	datatype x;

	while(1)
	{
		printf("Please input a number(-1 exit:");
		while(scanf("%d",&x.fd) != 1)
		{
			printf("Please input a number:(-1 exit");
			getchar();
		}
		if(x.fd == -1)break;
		insert_end_linklist(L,x);
	}
	return 0;
}
int insert_pos_linklist(linklist L,datatype x,int pos)
{
	linklist K,r;
	if(pos == 0)
	{
		r = L;
	}
	else
	{
		r = get_list_pos_linklist(L,pos-1);
	}
	if(r == NULL)
	{
		printf("argc is invalidateid!\n");
		return -1;
	}
	else
	{
		if((K = (linklist)malloc(sizeof(listnode))) == NULL)
		{
			printf("malloc no memmory!");
			return -1;
													}
		K->data = x;
		K->next = r->next;
		r->next = K;
	}
	return 0;
}
int insert_order_linklist(linklist L,datatype x)
{
	linklist r,H;
	if((H = (linklist)malloc(sizeof(listnode))) == NULL)
	{
		printf("malloc nexto memmory!\n");
		return -1;
	}
	H->data = x;

	r = L;
	while(r->next && r->next->data.fd < x.fd)
	{
		r = r->next;
	}
	H->next = r->next;
	r->next = H;
	return 0;
}
void reverse_linklist(linklist L)
{
	linklist r,p;

	if(L->next == NULL)
	{
		printf("list is NULL!\n");
		return ;
	}

	r = L->next;
	L->next = NULL;
	while(r)
	{
		p = r;
		r = r->next;

		p->next = L->next;
		L->next = p;
	}
	return ;
}
void sort_linklist(linklist L)
{
	linklist r,p,q;
	if(L == NULL)
	{
		printf("list is NULL!\n");
		return ;
	}
	r = L->next;
	L->next = NULL;
	while(r)
	{
		p = r;
		r = r->next;

		q = L;
		while(q->next && q->next->data.fd < p->data.fd)
		{
			q = q->next;
		}
		p->next = q->next;
		q->next = p;
	}
}

void show_linklist(linklist L)
{
	printf("list is:\n");
	if(L->next == NULL)
	{
		printf("\tlist is NULL!list\n");
		return ;
	}
	while(L->next)
	{
		printf("\t%d %s %d\t",L->next->data.fd,L->next->data.ipv4_addr,L->next->data.port);
		L = L->next;
		puts("");
	}
	//puts("");
	return ;
}

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