parser.bas

Windows网络编程技术源码 (是Windows网络编程技术配套的一本源码教程）

Attribute VB_Name = "parser"
'
' This file contains routines for parsing IP packets and generating
'  human readable text. Note that a parser for every protocol is not
'  provided. We parse only those protocols were interested in: TCP,
'  UDP, IGMP, etc.
'

Option Explicit
Option Base 0


Global Const MAX_IP_SIZE = 65535
Global Const MIN_IP_HDR_SIZE = 20
Global szProto() As String
Global szIgmpType() As String
Global bFilter As Boolean

Sub FillSzProto()
                 ReDim szProto(100)
                 szProto(0) = "Reserved"     '//  0
                 szProto(1) = "ICMP"         '//  1
                 szProto(2) = "IGMP"         '//  2
                 szProto(3) = "GGP"          '//  3
                 szProto(4) = "IP"           '//  4
                 szProto(5) = "ST"           '//  5
                 szProto(6) = "TCP"          '//  6
                 szProto(7) = "UCL"          '//  7
                 szProto(8) = "EGP"          '//  8
                 szProto(9) = "IGP"          '//  9
                 szProto(10) = "BBN-RCC-MON" '// 10
                 szProto(11) = "NVP-II"      '// 11
                 szProto(12) = "PUP"         '// 12
                 szProto(13) = "ARGUS"       '// 13
                 szProto(14) = "EMCON"       '// 14
                 szProto(15) = "XNET"        '// 15
                 szProto(16) = "CHAOS"       '// 16
                 szProto(17) = "UDP"         '// 17
                 szProto(18) = "MUX"         '// 18
                 szProto(19) = "DCN-MEAS"    '// 19
                 szProto(20) = "HMP"         '// 20
                 szProto(21) = "PRM"         '// 21
                 szProto(22) = "XNS-IDP"     '// 22
                 szProto(23) = "TRUNK-1"     '// 23
                 szProto(24) = "TRUNK-2"     '// 24
                 szProto(25) = "LEAF-1"      '// 25
                 szProto(26) = "LEAF-2"      '// 26
                 szProto(27) = "RDP"         '// 27
                 szProto(28) = "IRTP"        '// 28
                 szProto(29) = "ISO-TP4"     '// 29
                 szProto(30) = "NETBLT"      '// 30
                 szProto(31) = "MFE-NSP"     '// 31
                 szProto(32) = "MERIT-INP"   '// 32
                 szProto(33) = "SEP"         '// 33
                 szProto(34) = "3PC"         '// 34
                 szProto(35) = "IDPR"        '// 35
                 szProto(36) = "XTP"         '// 36
                 szProto(37) = "DDP"         '// 37
                 szProto(38) = "IDPR-CMTP"   '// 38
                 szProto(39) = "TP++"        '// 39
                 szProto(40) = "IL"          '// 40
                 szProto(41) = "SIP"         '// 41
                 szProto(42) = "SDRP"        '// 42
                 szProto(43) = "SIP-SR"      '// 43
                 szProto(44) = "SIP-FRAG"    '// 44
                 szProto(45) = "IDRP"        '// 45
                 szProto(46) = "RSVP"        '// 46
                 szProto(47) = "GRE"         '// 47
                 szProto(48) = "MHRP"        '// 48
                 szProto(49) = "BNA"         '// 49
                 szProto(50) = "SIPP-ESP"    '// 50
                 szProto(51) = "SIPP-AH"     '// 51
                 szProto(52) = "I-NLSP"      '// 52
                 szProto(53) = "SWIPE"       '// 53
                 szProto(54) = "NHRP"        '// 54
                 szProto(55) = "unassigned"  '// 55
                 szProto(56) = "unassigned"  '// 56
                 szProto(57) = "unassigned"  '// 57
                 szProto(58) = "unassigned"  '// 58
                 szProto(59) = "unassigned"  '// 59
                 szProto(60) = "unassigned"  '// 60
                 szProto(61) = "any host internal protocol" '// 61
                 szProto(62) = "CFTP"        '// 62
                 szProto(63) = "any local network"          '// 63
                 szProto(64) = "SAT-EXPAK"   '// 64
                 szProto(65) = "KRYPTOLAN"   '// 65
                 szProto(66) = "RVD"         '// 66
                 szProto(67) = "IPPC"        '// 67
                 szProto(68) = "any distributed file system"  '// 68
                 szProto(69) = "SAT-MON"   '// 69
                 szProto(60) = "VISA"      '// 70
                 szProto(71) = "IPCV"      '// 71
                 szProto(72) = "CPNX"      '// 72
                 szProto(73) = "CPHB"      '// 73
                 szProto(74) = "WSN"       '// 74
                 szProto(75) = "PVP"       '// 75
                 szProto(76) = "BR-SAT-MON"  '// 76
                 szProto(77) = "SUN-ND"    '// 77
                 szProto(78) = "WB-MON"    '// 78
                 szProto(79) = "WB-EXPAK"  '// 79
                 szProto(80) = "ISO-IP"    '// 80
                 szProto(81) = "VMTP"      '// 81
                 szProto(82) = "SECURE-VMTP" '// 82
                 szProto(83) = "VINES"     '// 83
                 szProto(84) = "TTP"       '// 84
                 szProto(85) = "NSFNET-IGP"  '// 85
                 szProto(86) = "DGP"       '// 86
                 szProto(87) = "TCF"       '// 87
                 szProto(88) = "IGRP"      '// 88
                 szProto(89) = "OSPFIGP"   '// 89
                 szProto(90) = "Sprite-RPC"  '// 90
                 szProto(91) = "LARP"      '// 91
                 szProto(92) = "MTP"       '// 92
                 szProto(93) = "AX.25"     '// 93
                 szProto(94) = "IPIP"      '// 94
                 szProto(95) = "MICP"      '// 95
                 szProto(96) = "SCC-SP"    '// 96
                 szProto(97) = "ETHERIP"   '// 97
                 szProto(98) = "ENCAP"     '// 98
                 szProto(98) = "any private encryption scheme"   '// 98
                 szProto(99) = "GMTP"        '// 99
End Sub


'//
'// The types of IGMP messages
'//
Sub FillSzIgmpType()
    ReDim szIgmpType(8)
    szIgmpType(0) = ""
    szIgmpType(1) = "Host Membership Query"
    szIgmpType(2) = "Host Membership Report"
    szIgmpType(3) = ""
    szIgmpType(4) = ""
    szIgmpType(5) = ""
    szIgmpType(6) = "Version 2 Membership Report"
    szIgmpType(7) = "Leave Group"
End Sub

'
' Function: HI_WORD
'
' Description:
'    This function returns the high 4 bits of a byte
'
Function HI_WORD(bt As Byte) As Long
    HI_WORD = (CLng(bt) \ 16) And &HF&
End Function

'
' Function: LO_WORD
'
' Description:
'    This function returns the low 4 bits of a byte
'
Function LO_WORD(bt As Byte) As Long
    LO_WORD = CLng(bt) And &HF&
End Function


'//
'// Function: PrintRawBytes
'//
'// Description:
'//    This function simply prints out a series of bytes
'//    as hexadecimal digits.
'//
Function PrintRawBytes(ptr() As Byte, ByVal dwlen As Long) As String
    Dim i As Long
    Dim ptrpos As Long
    Dim strHex As String
    
    ptrpos = 0
    Do While dwlen > 0
        strHex = ""
        For i = 0 To 19
            strHex = strHex & Hex(HI_WORD(ptr(ptrpos))) & Hex(LO_WORD(ptr(ptrpos))) & " "
            dwlen = dwlen - 1
            ptrpos = ptrpos + 1
            If dwlen = 0 Then Exit Do
        Next i
        frmrcvall.List2.AddItem strHex
    Loop
    PrintRawBytes = strHex
    
End Function


'//
'// Function: DecodeIGMPHeader
'//
'// Description:
'//    This function takes a pointer to a buffer containing
'//    an IGMP packet and prints it out in a readable form.
'//
Sub DecodeIGMPHeader(ptr() As Byte, ByVal iphdrlen As Long)
    Dim chksum As Long, version As Long, ntype As Long, maxresptime As Long
    Dim addr As sockaddr
    Dim hdr As Byte
    Dim pos As Long
    Dim strIGMPHeader As String
    
    pos = iphdrlen
    hdr = ptr(pos)
    strIGMPHeader = ""
    
    version = HI_WORD(hdr)
    ntype = LO_WORD(hdr)
    
    pos = pos + 1
    
    maxresptime = ptr(pos)
    pos = pos + 1
    
    CopyMemory chksum, ptr(pos), 2
    chksum = ntohs(chksum) And &HFFFF&
    pos = pos + 2
    
    CopyMemory addr.sin_addr, ptr(pos), 4
    frmrcvall.List2.AddItem "   IGMP HEADER:"
    
    If ntype = 1 Or ntype = 2 Then
        version = 1
    Else
        version = 2
    End If
    
    frmrcvall.List2.AddItem "   IGMP Version = " & version
    frmrcvall.List2.AddItem "   IGMP Type = " & szIgmpType(ntype)
    
    If version = 2 Then
        Dim strIP As String
        strIP = String(256, 0)
        lstrcpy1 strIP, inet_ntoa(addr.sin_addr)
        strIP = Trim(strIP)
        frmrcvall.List2.AddItem "   IGMP Grp Addr = " & strIP
    End If