portscan.c

一个端口扫描程序！在linux环境c语言实现！

#include <stdio.h>
#include <netinet/in.h> 
#include <sys/types.h> 
#include <sys/socket.h> 
#include <sys/signal.h> 
#include <sys/time.h> 
#include <fcntl.h> 
#include <unistd.h> 
#include <sys/ioctl.h> 

#define N 11 

int	port[N] ={ 
		80,81,88,8083,8080,8001,8888,3128,3124,3000,1080}; /* 欲搜的端口号 */ 
int 		status=-1; 
char 	serverName[20]; 
u_char 	p1,p2,p3,p4; 
int 		sockfd=-1; 
struct 	timeval timeout={2,0}; 
fd_set 	mask; 
FILE 	*f=NULL;                           
int 		err; 
int 		errlen; 
u_long 	startIP,endIP,k; 

void terminate(int sig) /* 异常中止处理子程程序 */
{ 
	p1=(u_char)( (k>>24) & 0xFF); p2=(u_char)( (k>>16) & 0xFF); 
	p3=(u_char)( (k>>8 ) & 0xFF); 
	p4=(u_char)( k & 0xFF); 
	fprintf(f,"%d.%d.%d.%d killed.\n",p1,p2,p3,p4); 
	fclose(f); 
	if(sockfd>0) close(sockfd); 
	exit(0); 
} 

void findProxy(u_long addr) 
{ 
	int i; 
	struct sockaddr_in host;
	/*若连上了主机,则看其所有有可能提供proxy服务的端口 */ 
	for(i=0;i<N;i++) 
	{ 
		host.sin_family=AF_INET; 
		host.sin_addr.s_addr=htonl(addr); 
		host.sin_port=htons(port[i]); 
		if ( (sockfd=socket(AF_INET,SOCK_STREAM,0))<0 ) 
		{ 
			fprintf(f," Error open socket\n"); 
			exit(-1); 
		}
		/* 试连一个可能提供proxy服务的一个端口 */ 
		/* O_NDELAY = FNDELAY = O_NONBLOCK */ 
		if(fcntl(sockfd,F_SETFL,O_NDELAY) < 0 ) 	/* 设置为非阻塞式socket */ 
		{ 
			fprintf(f,"fcntl() error\n"); 
			exit(-1); 
		} 
		status=connect(sockfd,(struct sockaddr *)& host,sizeof(host)); 
		timeout.tv_sec=1; 
		timeout.tv_usec=0; 		/* 设置超时限制 */ 
		FD_ZERO( & mask); 
		FD_SET(sockfd,& mask); 
		status=select(sockfd+1,(fd_set *)0,& mask, (fd_set *)0,& timeout); 

		switch(status) 
		{ 
			case -1: 
				fprintf(f,"select error\n"); 
				fclose(f); 
				close(sockfd); 
				exit(-1); 
			case 0: 				/* 如果连接超时 */ 
				close(sockfd); 
				return; 
			default: 				/* 如果连接成功 */ 
				if( FD_ISSET(sockfd,& mask) ) 
				{ 
					err=1; 
					errlen=1; 
					getsockopt(sockfd,SOL_SOCKET,SO_ERROR,(char*)&err,&errlen); 
					if(err==0) 
						fprintf(f,"%s\t%d\n",serverName,port[i]); 
				} 
		} 
		close(sockfd); 
		fflush(f);
	}
}
	 
main(int argc,char *argv[]) 
{ 
	int i; 
	if(argc!=4) 
	{ 
		printf("Usage: %s startIP endIP logFile\n",argv[0]); 
		exit(-1); 
	} 
	startIP=ntohl(inet_addr(argv[1])); /* 搜索的IP范围 */ 
	endIP=ntohl(inet_addr(argv[2])); 
	if(startIP>endIP) 
	{ 
		k=startIP; 
		startIP=endIP; 
		endIP=k; 
	}
	f=fopen(argv[3],"a"); 		/* 打开日志文件 */ 
	if(f==NULL) 
	{ 
		printf("error open log file: %s\n",argv[3]); 
		exit(-1); 
	} 
	fprintf(f,"%s--------->%s\n",argv[1],argv[2]); 
	fflush(f); 
	printf("Searching proxy...\n"); 
	printf("%s----------->%s\n",argv[1],argv[2]); 
	printf("\tport:\n"); 
	for( i=0;i<N;i++) 
		printf("\t%d\n",port[i]); 
	signal(SIGTERM,terminate); 		/* 设置异常中止处理 */ 
	switch(fork()) 
	{ 
		case 0: 			/* 如果是子进程则继续执行 */ 
			break; 
		case -1: 			/* 出错 */ 
			printf("fork() error\n"); 
			exit(-1); 
		default: 			/* 如果是父进程则结束该进程 */ 
			fclose(f); 
			exit(0); 
	}
	setpgid(0, getpgrp()); 
	i=open("/dev/tty",O_RDWR); 		/* 切断与控制台的联系 */ 
	if(i>=0) 
	{ 
		ioctl(i,TIOCNOTTY,0); 
		close(i); 
	}
	else { 
		fprintf(f,"TTY eacape error\n"); 
		fflush(f); 
	} 
	for(k=startIP;k<=endIP;k++) 
	{ 
		if( (k % 256)==0) 
			continue; /* localhost */ 
		if( (k % 256)==255) 
			continue; /* broadcast */ 
		p1=(u_char)( (k>>24) & 0xFF); 
		p2=(u_char)( (k>>16) & 0xFF); 
		p3=(u_char)( (k>>8 ) & 0xFF); 
		p4=(u_char)( k & 0xFF); 
		sprintf(serverName,"%d.%d.%d.%d",p1,p2,p3,p4); 
		findProxy(k); 
	}
	fprintf(f,"All done\n"); 
	fclose(f); 
}