[linux,c++] 网络编程之多线程扫描服务器端口编程

先把代码贴出来，详细的流程与注释明天再写
首先是服务器端的代码，程序的主体部分是客户端的多线程扫描，所以服务器端的代码编写的相对简单，没有过多的安全性检查的处理。

// my_server.cpp 
// g++ my_server.cpp -o server

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

int main (int c , char ** v)
{
    struct sockaddr_in server_addr ;
    int sockfd ;

    sockfd = socket ( AF_INET , SOCK_STREAM , 0 ) ;

        server_addr.sin_family = AF_INET ;
        server_addr.sin_port = htons (1027) ;
        inet_aton ("127.0.0.1" , &server_addr.sin_addr ) ;

        bind (sockfd ,(struct sockaddr*)&server_addr , sizeof(struct sockaddr_in) ) ;
        listen ( sockfd , 10 ) ;

    for (;;) {}

    return 0 ;
}

---

---

// 后面的代码均属于 client 端，使用Makefile 进行编译
// Makefile

CPPFLAGS = -O3
LDFLAGS = -lpthread

all: Main

clean :
    rm -f *.o

Main: Main.o my_scanner.o
    g++ -o $@ $^ $(LDFLAGS)

// my_scanner.h

// my_scanner.h
#ifndef MY_SCANNER_H
#define MY_SCANNER_H

#include <cstdio>
#include <cstring>
#include <cstdlib>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <errno.h>

#include <pthread.h>
#include <vector>


struct _scan_segment
{
   unsigned short int from_port ;
   unsigned short int to_port ;
   struct in_addr     scan_addr ;
} ;

typedef _scan_segment scanSegment ;


class Scanner
{
  private :
    std::vector<pthread_t> pthreadList ;
    int threadNum ;
    int            connfd ;
    struct in_addr scan_addr ;
    int scan_max_port ;
    int        scan_len ;

  public :
    Scanner ( int _threadNum , struct in_addr _scan_addr , int _scan_max_port ) ;

// static    int do_scan ( struct sockaddr_in ) ;
//    void * scanner ( void *) ;
    void run ( void ) ;

} ;

#endif // my_scanner.h

// myscanner.cpp

// myscanner.cpp
#include "my_scanner.h"

using namespace std ;

static void log_info ( const char *err_info , int location )
{
    fprintf (stderr, "[error]: %s, [line]: %d\n" ,     err_info , location) ;
    perror ("exit function errinfo ") ;
    exit ( 1 ) ;
}


Scanner::Scanner ( int _threadNum , struct in_addr _scan_addr , int _scan_max_port )
{

    threadNum = _threadNum ;
    scan_max_port = _scan_max_port ;


    if ( threadNum > scan_max_port )
        threadNum = scan_max_port ;

    scan_len = scan_max_port / threadNum ;


    // copy addr
    scan_addr = _scan_addr ;

    for ( int i = 0 ; i < threadNum ; i++ )
    {
        pthread_t thread ;
        pthreadList.push_back ( thread ) ;
    }
}


int do_scan ( struct sockaddr_in dest_addr )
{
    int ret , conn_fd = socket ( AF_INET , SOCK_STREAM , 0 ) ;

    if ( conn_fd < 0 )
         log_info ("socket" , __LINE__) ;

    ret = connect ( conn_fd , (struct sockaddr *)&dest_addr ,
                sizeof ( struct sockaddr_in )) ;
     if ( ret < 0 )
     {
        if ( errno == ECONNREFUSED )
        {
            close (conn_fd ) ;
            return -1; // target port refused service
        }
        else
        {
            close ( conn_fd ) ;
            return -2; // other error type
        }

     }
    else
    {

        printf ("port %d found in %s \n" , ntohs(dest_addr.sin_port) , inet_ntoa(dest_addr.sin_addr)) ;
        close (conn_fd) ;
        return 1 ;
    }
    return 0 ;
}


void* scanner ( void *arg )
{
    unsigned short int i ;
    scanSegment scan_segment ;
    struct sockaddr_in dest_addr ;

    memcpy ( &scan_segment , arg , sizeof ( scanSegment )) ;

    dest_addr.sin_family      = AF_INET ;
    dest_addr.sin_addr = scan_segment.scan_addr ;

    for ( i = scan_segment.from_port ; i != scan_segment.to_port ; i++ )
    {
        dest_addr.sin_port = htons ( i ) ;

        printf ("detected by   thread %lu , results :\n" , pthread_self() ) ;

        switch ( do_scan ( dest_addr ) )
        {
            case -1 :
                printf ("refused service\n" ,i ) ;
            break ;

            case -2 :
                printf ("other type error \n" , i ) ;
            break ;

            case 1:
                printf ("check port %d free " , i ) ;
            break ;
            default :
                printf ("unknown error \n") ;
        }

    }

}

void Scanner::run ()
{
    scanSegment segment ;
    segment.scan_addr = scan_addr ;


    for ( int i = 0 ; i < threadNum ; i++ )
    {
        segment.from_port = i*scan_len + 1 ;

        if ( i == threadNum -1 )
        {
            segment.to_port = scan_max_port ;
        }
        else
        {
            segment.to_port = segment.from_port + scan_len -1 ;
        }

        if ( pthread_create ( &pthreadList[i] , NULL , scanner , (void *)&segment ) )
        {
            log_info ("pthread_create" , __LINE__) ;
        }

        pthread_join ( pthreadList[i] , NULL ) ;
    }
}

// Main.cpp

// Main.cpp

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

#include "my_scanner.h"

using namespace std ;

void usage_info ( void )
{
    printf ("method usage : \n") ;
    printf ("[-m][max port ]\t [-a][server address \"xxx.xxx.xxx.xxx\"]\t [-n][-thread number] \n") ;
}


int main ( int argc , char *argv[] )
{
  int i ;
  int max_port ; // -m
  int thread_num ; // -n
  struct in_addr destAddr ; // -a

  Scanner *myScanner ;


  for ( i = 0 ; i < argc ; i++ )
  {
     if ( strcmp ( "-m" , argv[i] ) == 0 )
     {
        max_port = atoi (argv[i+1]) ;
         if ( max_port < 0 || max_port > 65536 )
        {
            perror (" invalid port number ") ;
            return -1 ;
        }
     }

    if ( strcmp ( "-a" , argv[i] ) == 0 )
    {
        printf ("input ip address  : %s \n", argv[i+1]) ;

        if ( inet_aton (argv[i+1] , &destAddr ) < 0 )
        {
            perror (" invalid ip address ") ;
            return -1 ;
        }
    }

    if ( strcmp ( "-n" , argv[i] ) == 0 )
    {
        thread_num = atoi (argv[i+1]) ;

        if ( thread_num <= 0 )
        {
            perror (" invalid threadnum ") ;
            return -1 ;
        }
    }
  }

  printf ("here is the info you input\n") ;
  printf ("max port : %d \n" , max_port ) ;
 // printf ("address ip : %s\n", inet_nota (destAddr) ) ;
  printf ("thread number : %d \n" , thread_num) ;


  myScanner = new Scanner (thread_num , destAddr , max_port ) ;
  myScanner->run () ;


  goto success ;

  error :
    printf ("main error") ;
    goto success ;
 success:
    return 0 ;
}

---

---

程序运行顺序：
1. 首先在一个 terminal 中运行 ./server
2. 然后在新开启一个 terminal 输入命令
-m (你要扫描检测的端口的最大值 [0,65535]) -a (你要检查端口所在的主机 IP 以 xxx.xxx.xxx.xxx 的格式) -n (你要开启多少个线程并行检查端口)
例如
 -m 1027 -a 127.0.0.1 -n 100

end