作者：jhkdiy
邮件：jhkdiy_gzb@21cn.net
论坛：624K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8Y4N6%4N6#2)9J5k6e0t1H3j5$3&6Q4x3X3g2F1k6i4b7`.
日期：06年3月24日

    有一段时间没有去过ASMCommunity Messageboard（f08K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8Y4N6%4N6#2)9J5k6h3q4K6L8h3y4G2L8h3#2#2L8X3W2@1P5g2)9J5k6h3&6W2N6q4)9J5c8X3u0G2j5i4u0V1i4K6u0r3K9h3&6V1k6i4S2Q4x3X3g2H3K9s2m8Q4c8f1k6Q4b7V1y4Q4z5o6W2Q4c8e0c8Q4b7V1q4Q4z5o6k6Q4c8f1k6Q4b7V1y4Q4z5p5y4Q4c8e0c8Q4b7V1u0Q4b7e0g2Q4c8e0g2Q4z5o6W2Q4z5p5c8Q4c8e0N6Q4z5f1u0Q4b7U0c8Q4c8e0k6Q4z5p5g2Q4b7e0g2Q4c8e0g2Q4z5p5k6Q4b7f1k6Q4c8e0c8Q4b7V1u0Q4b7e0g2Q4c8e0S2Q4b7f1g2Q4b7V1k6Q4c8e0W2Q4z5e0N6Q4b7f1g2Q4c8e0y4Q4z5o6m8Q4z5o6t1`.
现在只能通过代理才能访问，至少我这边是这样。在里面随便逛了逛，无意看到一位论坛会员问怎样用Asm来做一个端口扫描器，
结果其他会员给了一个源代码，在window的控制台窗口下运行，以阻塞模式扫描一个目标主机的端口。我觉得这个代码对刚学习
Windows Socket编程的朋友来说很有启发性，所以现在详细讲解一下这份代码，希望对大家有所帮助。若各位读者想先试试该程序
可以先用RadAsm建立一个console工程，然后将下面的代码粘贴到asm文件中，编译＆链接。在控制台下运行该程序即可。
源代码如下，只做了一点的格式编排：

; Conscan - CLI "test"
.386 
.model flat, stdcall 
option casemap :none

include windows.inc 
include user32.inc 
include kernel32.inc 
include masm32.inc
include wsock32.inc
includelib user32.lib 
includelib kernel32.lib 
includelib masm32.lib
includelib wsock32.lib

print macro lpszText:VARARG
 local txt
 .data
  txt db lpszText,13,10,0
 .code
  invoke StdOut,addr txt
ENDM

SOCKADDR_IN struct
 sin_family WORD ?
 sin_port WORD ?
 sin_addr DWORD ?
 sin_zero BYTE 8 dup (?)
SOCKADDR_IN ends

.data
 szusg db "usage: conscan <hostname>",13,10,0
 fmt   db "%d OPEN",13,10,0
 sa    SOCKADDR_IN <>
 wsa   WSADATA <>
 sfd   dd 0
 port  dd 0
 pl    dd 21
       dd 22
       dd 23
       dd 25
       dd 80
       dd 137
       dd 350
       dd 8080
       dd 6667
       dd 31337
       dd 0
     
.data?
 hostname db 2024 dup (?)
 buffer   db 100 dup (?)
 
.code
conscan:
 call main
 call ExitProcess

main proc
    invoke GetCL,1,addr hostname
    cmp eax,1
    jne Arg_Error
    
    mov sa.sin_family, AF_INET
    lea edi,pl
Port_Scan_Loop:
    mov eax,[edi]
    cmp eax,0
    je Port_Scan_Complete
    inc edi
    mov port,eax
    invoke WSAStartup,101h,addr wsa
    invoke socket, AF_INET, SOCK_STREAM, 0
    mov sfd,eax
    invoke htons, port
    mov sa.sin_port, ax
    invoke gethostbyname, addr hostname   
    mov eax,[eax+12]
    mov eax,[eax]
    mov eax,[eax] 
    mov sa.sin_addr,eax
    invoke connect,sfd,addr sa,SIZEOF sa
    cmp eax, 0
    jne Port_Closed
    invoke wsprintf,addr buffer,addr fmt,port
    invoke StdOut,addr buffer
Port_Closed:
    invoke closesocket,sfd
    call WSACleanup
    jmp Port_Scan_Loop
Arg_Error:
    invoke StdOut,addr szusg
    ret
Port_Scan_Complete:
    print "-- Scan Complete --"
    ret
main endp
end conscan

.code
conscan:
 call main              ;主函数，全部流程都在这里了。
 call ExitProcess       ;正常终止程序必须的。

main proc
    invoke GetCL,1,addr hostname        ;GetCL是masm32.inc中函数
    cmp eax,1
    jne Arg_Error
    
    mov sa.sin_family, AF_INET
    lea edi,pl
Port_Scan_Loop:
    mov eax,[edi]
    cmp eax,0
    je Port_Scan_Complete
    inc edi
    mov port,eax
    invoke WSAStartup,101h,addr wsa
    invoke socket, AF_INET, SOCK_STREAM, 0
    mov sfd,eax
    invoke htons, port
    mov sa.sin_port, ax
    invoke gethostbyname, addr hostname   
    mov eax,[eax+12]
    mov eax,[eax]
    mov eax,[eax] 
    mov sa.sin_addr,eax
    invoke connect,sfd,addr sa,SIZEOF sa
    cmp eax, 0
    jne Port_Closed
    invoke wsprintf,addr buffer,addr fmt,port
    invoke StdOut,addr buffer
Port_Closed:
    invoke closesocket,sfd
    call WSACleanup
    jmp Port_Scan_Loop
Arg_Error:
    invoke StdOut,addr szusg
    ret
Port_Scan_Complete:
    print "-- Scan Complete --"
    ret
main endp
end conscan

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