mac/unix系统：C++实现一个端口扫描器

Posted 2020-08-27 方方和圆圆

　　简易端口扫描器

　　在比较早以前，我用过S扫描器， 以及大名鼎鼎的nmap扫描器， 可以快速扫描某个主机开放的端口， 今天使用C实现这样一个软件，

　　编译环境为Mac， 系统版本10.11.6：

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

void msg()  
{  
  printf("EP:scan ip startport endport\\nEP:scan ip 127.0.0.1 20 2009\\n");  
}  
int main(int argc,char** argv)  
{  
  char *ip;  
  int startport,endport,sockfd,i;  
  struct sockaddr_in to;  
  float costtime;  
  clock_t start,end;  
  if(4!=argc)  
  {  
    msg();  
    return 0;  
  }  
  ip=argv[1];  
  startport=atoi(argv[2]);  
  endport=atoi(argv[3]);  
  if(startport<1 || endport>65535 || endport<startport)  
  {  
    printf("端口范围出错/n");  
    return 0;   
  }  
  else{
    printf("IP:%s %d-%d\\n",ip,startport,endport);  
  }
  to.sin_family=AF_INET;  
  to.sin_addr.s_addr=inet_addr(ip);  
  start=clock();  
  for(i=startport;i<=endport;i++)  
  {  
    sockfd=socket(AF_INET,SOCK_STREAM,0);  
    to.sin_port=htons(i);  
    if(connect(sockfd,(struct sockaddr *)&to,sizeof(struct sockaddr)) == 0) {
         printf("%s    %d\\n",ip,i);
         close(sockfd);
    };
  }  
  end=clock();  
  costtime=(float)(end-start)/CLOCKS_PER_SEC;  
  printf("用时:%f秒\\n",costtime);  
  return 0;  
}  

　　亲测可行：

　　以上的代码只能检测固定的ip， 通过更改源码， 软件可以支持一段的ip端口检测， 多加一个循环：

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <string.h>
#include <fcntl.h>
#include <sys/select.h>
#include <string>
void msg()
{
    printf( "EP:scan ip startport endport\\nEP:scan ip 127.0.0.1 20 2009\\n" );
    printf( "EP:scan ip endip startport endport\\nEP:scan ip 127.0.0. 250 20 2009\\n" );
}
void runsock(int sockfd, struct sockaddr_in to, char *ipval, int i) {
    sockfd = socket( AF_INET, SOCK_STREAM, 0 );
    //fcntl(sockfd, F_SETFL, O_NONBLOCK);
    to.sin_port    = htons( i );
    //printf( "IP:%s  %d\\n", ipval, i );
    if ( connect( sockfd, (struct sockaddr *) &to, sizeof(struct sockaddr) ) == 0 ){
        printf( "%s    %d\\n", ipval, i );
        close( sockfd );
    }
}

int main( int argc, char* argv[] ){
    char            * ip;
    char            * endip;
    int            startport, endport, sockfd, i;
    struct sockaddr_in    to;
    float            costtime;
    clock_t            start, end;
    if ( 4 == argc ){
        ip        = argv[1];
        startport    = atoi( argv[2] );
        endport        = atoi( argv[3] );
        if ( startport < 1 || endport > 65535 || endport < startport ){
            printf( "端口范围出错/n" );
            return(0);
        }else{
            printf( "IP:%s %d-%d\\n", ip, startport, endport );
        }
        to.sin_family        = AF_INET;
        to.sin_addr.s_addr    = inet_addr( ip );
        start            = clock();
        for ( i = startport; i <= endport; i++ ){
            runsock(sockfd, to, ip, i);
        }
        end        = clock();
        costtime    = (float) (end - start) / CLOCKS_PER_SEC;
        printf( "用时:%f秒\\n", costtime );
        return(0);
    }else if ( 5 == argc ){
        ip        = argv[1];
        endip        = argv[2];
        startport    = atoi( argv[3] );
        endport        = atoi( argv[4] );
        char *tempip;
        if ( startport < 1 || endport > 65535 || endport < startport ){
            printf( "端口范围出错/n" );
            return(0);
        }else{
            /* 循环ip地址 */
            start = clock();
            char ipval[20];
            for ( int j = 1; j <= atoi( endip ); j++ ){
                sprintf( ipval, "%s%d", ip, j );
                printf( "IP:%s\\n", ipval );
                to.sin_family        = AF_INET;
                to.sin_addr.s_addr    = inet_addr( ipval );
                for ( i = startport; i <= endport; i++ ){
                    runsock(sockfd, to, ipval, i);
                }
            }
            end        = clock();
            costtime    = (float) (end - start) / CLOCKS_PER_SEC;
            printf( "用时:%f秒\\n", costtime );
        };/* 循环端口 */
        return(0);
    }
    msg();
    return(0);
}

　　局域网网段IP端口扫描器

　　看起来这个扫描器是实现了， 但是还有一个天大的问题， 那就是connect是同步的， 如果有些ip是不存在的， 那么connect函数就会阻塞在那边， 导致运行非常缓慢，那就需要异步的socket连接， 涉及select.h， 通过icmp判断存活主机：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <signal.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netdb.h>
#include <setjmp.h>
#include <errno.h>
#include <sys/select.h>
#include <fcntl.h>

#define PACKET_SIZE 4096

/* 计算校验和的算法 */
unsigned short cal_chksum(unsigned short *addr,int len)
{
    int sum=0;
    int nleft = len;
    unsigned short *w = addr;
    unsigned short answer = 0;
    /* 把ICMP报头二进制数据以2字节为单位累加起来 */
    while(nleft > 1){
        sum += *w++;
        nleft -= 2;
    }
    /*
     * 若ICMP报头为奇数个字节，会剩下最后一字节。
     * 把最后一个字节视为一个2字节数据的高字节，
     * 这2字节数据的低字节为0，继续累加
     */
    if(nleft == 1){
        *(unsigned char *)(&answer) = *(unsigned char *)w;
        sum += answer;    /* 这里将 answer 转换成 int 整数 */
    }
    sum = (sum >> 16) + (sum & 0xffff);        /* 高位低位相加 */
    sum += (sum >> 16);        /* 上一步溢出时，将溢出位也加到sum中 */
    answer = ~sum;             /* 注意类型转换，现在的校验和为16位 */
    return answer;
}
int livetest(char* ip) {

    char    sendpacket[PACKET_SIZE];    /* 发送的数据包 */
    char    recvpacket[PACKET_SIZE];    /* 接收的数据包 */
    pid_t    pid;
    int    datalen = 56;    /* icmp数据包中数据的长度 */
    struct protoent *protocol;
    protocol = getprotobyname("icmp");
    int sockfd;
    int size = 50*1024;
    if((sockfd = socket(AF_INET, SOCK_RAW, protocol->p_proto)) < 0) {
        perror("socket error");
    }
    setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &size, sizeof(size) );
    
    struct sockaddr_in dest_addr;
    bzero(&dest_addr, sizeof(dest_addr));
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_addr.s_addr = inet_addr(ip);
    //send packet;
    int packsize;
    struct icmp *icmp;
    struct timeval *tval;
    icmp = (struct icmp*)sendpacket;
    icmp->icmp_type = ICMP_ECHO;    /* icmp的类型 */
    icmp->icmp_code = 0;            /* icmp的编码 */
    icmp->icmp_cksum = 0;           /* icmp的校验和 */
    icmp->icmp_seq = 1;       /* icmp的顺序号 */
    icmp->icmp_id = pid;            /* icmp的标志符 */
    packsize = 8 + datalen;   /* icmp8字节的头 加上数据的长度(datalen=56), packsize = 64 */
    tval = (struct timeval *)icmp->icmp_data;    /* 获得icmp结构中最后的数据部分的指针 */
    gettimeofday(tval, NULL); /* 将发送的时间填入icmp结构中最后的数据部分 */
    icmp->icmp_cksum = cal_chksum((unsigned short *)icmp, packsize);/*填充发送方的校验和*/

    if(sendto(sockfd, sendpacket, packsize, 0, (struct sockaddr *)&dest_addr, sizeof(dest_addr)) < 0){
        perror("sendto error");
    }
    //printf("send %d, send done\\n",1 );
    int n;
    struct sockaddr_in from;
    int fromlen = sizeof(from);
    fcntl(sockfd, F_SETFL, O_NONBLOCK);
    struct timeval timeo = {1,0};
    fd_set set;
    FD_ZERO(&set);
    FD_SET(sockfd, &set);

    //read , write;
    int retval = select(sockfd+1, &set, NULL, NULL, &timeo);
    if(retval == -1) {
        printf("select error\\n");
        return 0;
    }else if(retval == 0 ) {
        //printf("timeout\\n");
        return 0;
    }else{
        if( FD_ISSET(sockfd, &set) ){
            //printf("host is live\\n");
            return 1;
        }
        return 0;
    }
    // n = recvfrom(sockfd, recvpacket,sizeof(recvpacket), 0, (struct sockaddr *)&from, (socklen_t *)&fromlen);
    // if(n<0) {
    //     perror("recvfrom error");
    // }else{
    //     printf("%d\\n",n);
    // }
    //return 0;
}

static void sleep_ms(unsigned int secs){
    struct timeval tval;
    tval.tv_sec=secs/1000;
    tval.tv_usec=(secs*1000)%1000000;
    select(0,NULL,NULL,NULL,&tval);
}

void msg()
{
    printf( "EP:scan ip startport endport\\nEP:scan ip 127.0.0.1 20 2009\\n" );
    printf( "EP:scan ip endip startport endport\\nEP:scan ip 127.0.0. 1 250 20 2009\\n" );
}
void runsock(int sockfd, struct sockaddr_in to, char *ipval, int i) {
    sockfd = socket( AF_INET, SOCK_STREAM, 0 );
    fcntl(sockfd, F_SETFL, O_NONBLOCK);
    fd_set set,writeSet;
    int error; //错误代码  
    socklen_t len = sizeof(error); 
    //while(1){     
    FD_ZERO(&set);
    FD_ZERO(&writeSet);
    struct timeval timeo= {1,0};
    //socklen_t len = sizeof(timeo);
    FD_SET(sockfd,&set);
    FD_SET(sockfd,&set);
    //setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO,&timeo, len);
    to.sin_port    = htons( i );
    //printf( "test  %s    %d , sockfd value %d\\n", ipval, i , sockfd);
    //printf( "IP:%s  %d\\n", ipval, i );
    //printf("%d\\n",i);
    int conn = connect( sockfd, (struct sockaddr *) &to, sizeof(struct sockaddr) );
    //等待
    int retval = select(sockfd+ 1, &set, &writeSet, NULL, &timeo);

    getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &error, &len );  
    if(error == 0)  
        printf("%s Port %d is opened\\n", ipval, i);
    //printf("%d\\n",sockfd);
       // printf("%s :%d\\n",ipval, i);
    // if (retval== -1) {
    //     perror("select error\\n");
    // } else if(retval == 0){
    //     //printf("timeout\\n");
    // }else{
    //     //printf("find %s :%d\\n",ipval, i);    
    //     if(FD_ISSET(sockfd,&set)) {
    //         printf("find %s :%d\\n",ipval, i);    
    //     }
    // }
    //}
}

int main( int argc, char* argv[] ){
    char            * ip;
    int endip, startip;
    int            startport, endport, sockfd, i;
    struct sockaddr_in    to;
    float            costtime;
    clock_t            start, end;
    if ( 4 == argc ){
        ip        = argv[1];
        startport    = atoi( argv[2] );
        endport        = atoi( argv[3] );
        if ( startport < 1 || endport > 65535 || endport < startport ){
            printf( "端口范围出错/n" );
            return(0);
        }else{
            printf( "IP:%s %d-%d\\n", ip, startport, endport );
        }
        to.sin_family        = AF_INET;
        to.sin_addr.s_addr    = inet_addr( ip );
        start            = clock();
        for ( i = startport; i <= endport; i++ ){
            //printf("%d\\n",i);
            runsock(sockfd, to, ip, i);
        }
        end        = clock();
        costtime    = (float) (end - start) / CLOCKS_PER_SEC;
        printf( "用时:%f秒\\n", costtime );
        return(0);
    }else if ( 6 == argc ){
        ip        = argv[1];
        startip = atoi(argv[2]);
        endip        = atoi(argv[3]);
        startport    = atoi( argv[4] );
        endport        = atoi( argv[5] );
        char *tempip;
        if ( startport < 1 || endport > 65535 || endport < startport ){
            printf( "端口范围出错/n" );
            return(0);
        }else{
            /* 循环ip地址 */
            start = clock();
            char ipval[20];
            for ( int j = startip; j <= endip ; j++ ){
                sprintf( ipval, "%s%d", ip, j );
                printf( "IP:%s\\n", ipval );
                if(livetest(ipval) == 1){
                    to.sin_family = AF_INET;
                    //printf("okokok\\n");
                    to.sin_addr.s_addr = inet_addr( ipval );
                    for ( i = startport; i <= endport; i++ ){
                        runsock(sockfd, to, ipval, i);
                        sleep_ms(1000);
                    }    
                }
            }
            end    = clock();
            costtime = (float) (end - start) / CLOCKS_PER_SEC;
            printf( "用时:%f秒\\n", costtime );
        };
        //while(1){}
        /* 循环端口 */
        return(0);
    }
    msg();
    return(0);
}

 

 　　使用方式1： scan ip startport endport

sudo ./s 192.168.2.114 1  139

　　使用方式2: scan ip start endip startport endport

sudo ./s 192.168.1. 108 110 1 200

　　还有一个问题， 就是扫描的端口不怎么准确， 经常出现误报， 有些端口跟没开， 但是扫描器会显示目标端口有开， 应该是判断sock是否连接成功的逻辑有问题， 目前没有好的解决方案， 期待大神指点一下：

    getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &error, &len );  
    if(error == 0)  
        printf("%s Port %d is opened\\n", ipval, i);

 

　　参考链接

　　　　Linux C语言写的超级简单端口扫描器    http://blog.csdn.net/kongjiajie/article/details/4799986

　　　　Linux的SOCKET编程详解    http://blog.csdn.net/hguisu/article/details/7445768/

 

　　EOF

作者： NONO
出处：http://www.cnblogs.com/diligenceday/
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