mac/unix系統：C++實現一個端口掃描器

　　簡易端口掃描器

　　在比較早以前，我用過S掃描器， 以及大名鼎鼎的nmap掃描器， 可以快速掃描某個主機開放的端口， 今天使用C實現這樣一個軟件，

　　編譯環境為Mac， 系統版本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("端口范圍出錯/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("用時:%f秒\n",costtime);  
  return 0;  
}  

　　親測可行：

　　以上的代碼只能檢測固定的ip， 通過更改源碼， 軟件可以支持一段的ip端口檢測， 多加一個循環：

#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( "端口范圍出錯/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( "用時:%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( "端口范圍出錯/n" );
            return(0);
        }else{
            /* 循環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( "用時:%f秒\n", costtime );
        };/* 循環端口 */
        return(0);
    }
    msg();
    return(0);
}

　　局域網網段IP端口掃描器

　　看起來這個掃描器是實現了， 但是還有一個天大的問題， 那就是connect是同步的， 如果有些ip是不存在的， 那么connect函數就會阻塞在那邊， 導致運行非常緩慢，那就需要異步的socket連接， 涉及select.h， 通過icmp判斷存活主機：

#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

/* 計算校驗和的算法 */
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報頭二進制數據以2字節為單位累加起來 */
    while(nleft > 1){
        sum += *w++;
        nleft -= 2;
    }
    /*
     * 若ICMP報頭為奇數個字節，會剩下最后一字節。
     * 把最后一個字節視為一個2字節數據的高字節，
     * 這2字節數據的低字節為0，繼續累加
     */
    if(nleft == 1){
        *(unsigned char *)(&answer) = *(unsigned char *)w;
        sum += answer;    /* 這里將 answer 轉換成 int 整數 */
    }
    sum = (sum >> 16) + (sum & 0xffff);        /* 高位低位相加 */
    sum += (sum >> 16);        /* 上一步溢出時，將溢出位也加到sum中 */
    answer = ~sum;             /* 注意類型轉換，現在的校驗和為16位 */
    return answer;
}
int livetest(char* ip) {

    char    sendpacket[PACKET_SIZE];    /* 發送的數據包 */
    char    recvpacket[PACKET_SIZE];    /* 接收的數據包 */
    pid_t    pid;
    int    datalen = 56;    /* icmp數據包中數據的長度 */
    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的類型 */
    icmp->icmp_code = 0;            /* icmp的編碼 */
    icmp->icmp_cksum = 0;           /* icmp的校驗和 */
    icmp->icmp_seq = 1;       /* icmp的順序號 */
    icmp->icmp_id = pid;            /* icmp的標志符 */
    packsize = 8 + datalen;   /* icmp8字節的頭 加上數據的長度(datalen=56), packsize = 64 */
    tval = (struct timeval *)icmp->icmp_data;    /* 獲得icmp結構中最后的數據部分的指針 */
    gettimeofday(tval, NULL); /* 將發送的時間填入icmp結構中最后的數據部分 */
    icmp->icmp_cksum = cal_chksum((unsigned short *)icmp, packsize);/*填充發送方的校驗和*/

    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; //錯誤代碼  
    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( "端口范圍出錯/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( "用時:%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( "端口范圍出錯/n" );
            return(0);
        }else{
            /* 循環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( "用時:%f秒\n", costtime );
        };
        //while(1){}
        /* 循環端口 */
        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

　　還有一個問題， 就是掃描的端口不怎么准確， 經常出現誤報， 有些端口跟沒開， 但是掃描器會顯示目標端口有開， 應該是判斷sock是否連接成功的邏輯有問題， 目前沒有好的解決方案， 期待大神指點一下：

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

 

　　參考鏈接

　　　　Linux C語言寫的超級簡單端口掃描器    http://blog.csdn.net/kongjiajie/article/details/4799986

　　　　Linux的SOCKET編程詳解    http://blog.csdn.net/hguisu/article/details/7445768/

 

　　EOF

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