//TcpPortScanner.cc #include <iostream> #include <strings.h> #include <stdlib.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> using namespace std; int main(int argc, char *argv[]) { int fromport = atoi(argv[2]); int toport = atoi(argv[3]); if(fromport > toport) { int temp; temp = fromport; fromport = toport; toport = temp; } for(int i = fromport; i < toport; i++) { int sk = socket(AF_INET, SOCK_STREAM, 0); struct sockaddr_in server; bzero(&server, sizeof(server)); server.sin_family = AF_INET; server.sin_port = htons(i); server.sin_addr.s_addr = inet_addr(argv[1]); if(connect(sk, (struct sockaddr*)&server, sizeof(server)) == 0) { cout << argv[1] << "开放了端口:" << i << endl; } close(sk); } return 0; }
套接字socket(即sk)要在for循环里面创建,如果在for循环外面创建则第一次connect函数成功之后,sk并没有关闭,不能用来连接其他的端口,则下次的connect连接就会失败,所有只会扫描出一个开了的端口。
运行截图:
用一个tcpserver服务开启一个2020端口后运行截图: