/*
程序可以根據(jù)需要做適當(dāng)?shù)男薷? 使用-t 最好設(shè)置成5秒到10秒左右。否則將可能檢測(cè)不到下面的第一種情況。 1.如果局域網(wǎng)內(nèi)一臺(tái)電腦使用了應(yīng)用層防火墻比如天網(wǎng)之類,會(huì)connect超時(shí)。對(duì)方在線 2.connect success 連接成功,對(duì)方在線 3.connect refused 拒絕連接,對(duì)方在線 4.no route 連續(xù)發(fā)送5個(gè)arp請(qǐng)求(沒有結(jié)果)和一個(gè)dns查詢后(返回nxdomain),內(nèi)核產(chǎn)生no route的錯(cuò)誤。對(duì)方不在線 */ #include " stdio.h " #include " stdlib.h " #include " string.h " #include " unistd.h " #include " sys/types.h " #include " sys/time.h " #include " sys/socket.h " #include " arpa/inet.h " #include " netinet/in.h " #include " netdb.h " #include " fcntl.h " #include " errno.h " void usage() { printf( " use format:\n\t-s startip\n\t-e endip\n\t-t connect_timeout\n\t-p port\n " ); exit( - 1 ); }
int main( int argc, char ** argv)
{ int start_ip = 1 ; int end_ip = 254 ;
//設(shè)置超時(shí)時(shí)限 int time_connect = 10 ;
//設(shè)置端口號(hào) int port = 8888 ; int opt; while ((opt = getopt(argc, argv, " s:e:t:p: " )) != - 1 ) { switch (opt) { case ' s ' :start_ip = atoi(optarg); break ; case ' e ' :end_ip = atoi(optarg); break ; case ' t ' :time_connect = atoi(optarg); break ; case ' p ' :port = atoi(optarg); break ; case ' ? ' :usage(); break ; } } printf( " -----------------------------------------------------------------------------------------------------\n " ); printf( " \t scan will use 192.168.1.%d -> 192.168.1.%d with connect timeout %d in port %d\n " , start_ip, end_ip, time_connect, port); printf( " -----------------------------------------------------------------------------------------------------\n " ); struct timeval timeout; fd_set wset; fd_set rset; char straddr[ 100 ];
//按照地址1~254進(jìn)行掃描 for ( int i=start_ip; i<end_ip+ 1 ; i++ ) { //套接字 int sockfd = socket(AF_INET, SOCK_STREAM, 0 ); if (sockfd == - 1 )perror( " socket() " ); sprintf(straddr, " 192.168.1.%d\0 " , i); fprintf(stderr, " scan %s\t " , straddr);
//設(shè)置地址信息 struct sockaddr_in server_addr; server_addr.sin_family = AF_INET; if (inet_pton(AF_INET, straddr, &(server_addr.sin_addr)) != 1 )perror( " inet_pton() " ); server_addr.sin_port = htons(port); int flags; if ((flags = fcntl(sockfd, F_GETFL, 0 )) < 0 )perror( " fcntl() " ); if (fcntl(sockfd, F_SETFL, flags | O_NONBLOCK)< 0 )perror( " fcntl() " );
//連接 int result = connect(sockfd, ( struct sockaddr*)(&server_addr), sizeof (server_addr)); if (result == - 1 ) { if (errno == EINPROGRESS) { timeout.tv_sec = 10 ; timeout.tv_usec = 0 ; if (time_connect >= 100 ) { timeout.tv_sec = 0 ; timeout.tv_usec = time_connect; } else if (time_connect > 0 ) { timeout.tv_sec = time_connect; timeout.tv_usec = 0 ; }
//select機(jī)制,初始化 FD_ZERO( & wset);
//添加套接字 FD_SET(sockfd, & wset);
rset = wset; int n = select (sockfd+ 1 , &rset, &wset, 0 , & timeout); if (n == - 1 && errno!= EINTR) { perror( " select() error " ); } else if (n > 0 ) { int optval; int optlen = 4 ; if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, ( void *)&optval, (socklen_t*)&optlen) < 0 )perror( " getsockopt() " ); if (optval == 0 ) { fprintf(stderr, " success select\n " ); } else { fprintf(stderr, " failed select %d:%s\n " , optval, strerror(optval)); } } else if (n == 0 ) { fprintf(stderr, " connect timeout\n " ); } } else { close(sockfd); perror( " connect() " ); } } else { printf( " connect() success\n " ); close(sockfd); continue ; } close(sockfd); } return 0 ; }
已添加注釋~~~~~~~~~~~~~~~~~~
?轉(zhuǎn)自: http://blog.chinaunix.net/uid-9078996-id-2010266.html ?
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