我该怎么办？

[GirlScout]

我现在接收到了底层传来的数据包，我想从IP包头中把原IP和目的IP地址提取出来，请教各位，有没有将其中的十六进制地址信息转换成十进制的IP地址的VC库函数？

[feeboby]

我觉得这是最基本的编程能力了
好好补习一下c语言吧

[jennifergiant]

up

[zhouyong0371]

《Windows网络编程技术》第9章SIO_RCVALL实现了这种功能。解析IP包信息的代码如下：//
// Function: DecodeIPHeader
//
// Description:
// This function takes a pointer to an IP header and prints
// it out in a readable form.
//
int DecodeIPHeader(WSABUF *wsabuf, unsigned int srcip, unsigned short srcport,
unsigned int destip, unsigned short destport)
{
BYTE *hdr = (BYTE *)wsabuf->buf,
*nexthdr = NULL;
unsigned short shortval;
SOCKADDR_IN srcaddr,
destaddr;

unsigned short ip_version,
ip_hdr_len,
ip_tos,
ip_total_len,
ip_id,
ip_flags,
ip_ttl,
ip_frag_offset,
ip_proto,
ip_hdr_chksum,
ip_src_port,
ip_dest_port;
unsigned int ip_src,
ip_dest;
BOOL bPrint = TRUE;


ip_version = HI_WORD(*hdr);
ip_hdr_len = LO_WORD(*hdr) * 4;
nexthdr = (BYTE *)(wsabuf->buf + ip_hdr_len);
hdr++;

ip_tos = *hdr;
hdr++;

memcpy(&shortval, hdr, 2);
ip_total_len = ntohs(shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
ip_id = ntohs(shortval);
hdr += 2;

ip_flags = ((*hdr) >> 5);

memcpy(&shortval, hdr, 2);
ip_frag_offset = ((ntohs(shortval)) & 0x1FFF);
hdr+=2;

ip_ttl = *hdr;
hdr++;

ip_proto = *hdr;
hdr++;

memcpy(&shortval, hdr, 2);
ip_hdr_chksum = ntohs(shortval);
hdr += 2;

memcpy(&srcaddr.sin_addr.s_addr, hdr, 4);
ip_src = ntohl(srcaddr.sin_addr.s_addr);
hdr += 4;

memcpy(&destaddr.sin_addr.s_addr, hdr, 4);
ip_dest = ntohl(destaddr.sin_addr.s_addr);
hdr += 4;
//
// If packet is UDP, TCP, or IGMP read ahead and
// get the port values.
//
if (((ip_proto == 2) ||
(ip_proto == 6) ||
(ip_proto == 17)) &&
bFilter)
{
memcpy(&ip_src_port, nexthdr, 2);
ip_src_port = ntohs(ip_src_port);
memcpy(&ip_dest_port, nexthdr+2, 2);
ip_dest_port = ntohs(ip_dest_port);

if ((srcip == ip_src) ||
(srcport == ip_src_port) ||
(destip == ip_dest) ||
(destport == ip_dest_port))
{
bPrint = TRUE;
}
else
{
bPrint = FALSE;
}

}
else if (bFilter)
bPrint = FALSE;

// Print IP Hdr
//
if (bPrint)
{
printf("IP HEADER\n");
printf(" IP Version: %-10d | IP Header Len: %2d bytes | IP TOS: %X%X (hex)\n",
ip_version, ip_hdr_len, HI_WORD(ip_tos), LO_WORD(ip_tos));
printf(" IP Total Len: %-05d bytes | Identification: 0x%08X | IP Flags: %X (hex)\n",
ip_total_len, ip_id, ip_flags);
printf(" Frag Offset: 0x%08X | TTL: %-10d | Protocol: %-10s \n",
ip_frag_offset, ip_ttl, szProto[ip_proto]);
printf(" Hdr Checksum: 0x%08X\n", ip_hdr_chksum);
printf(" Src Addr: %-15s\n", inet_ntoa(srcaddr.sin_addr));
printf(" Dest Addr: %-15s\n", inet_ntoa(destaddr.sin_addr));
}
else
return ip_hdr_len;

switch (ip_proto)
{
case 2: // IGMP
DecodeIGMPHeader(wsabuf, ip_hdr_len);
break;
case 6: // TCP
DecodeTCPHeader(wsabuf, ip_hdr_len);
break;
case 17: // UDP
DecodeUDPHeader(wsabuf, ip_hdr_len);
break;
default:
printf(" No decoder installed for protocol\n");
break;
}
printf("\n");

return ip_hdr_len;
}

[zhouyong0371]

解析TCP Header:

//
// Function: DecodeTCPHeader
//
// Description:
// This function takes a buffer pointing to a TCP header
// and prints it out in a readable form.
//
int DecodeTCPHeader(WSABUF *wsabuf, DWORD iphdrlen)
{
BYTE *hdr = (BYTE *)(wsabuf->buf + iphdrlen);
unsigned short shortval;
unsigned int longval;

printf(" TCP HEADER\n");
memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval);
printf(" Src Port : %d\n", shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval);
printf(" Dest Port : %d\n", shortval);
hdr += 2;

memcpy(&longval, hdr, 4);
longval = ntohl(longval);
printf(" Seq Num : %d\n", longval);
hdr += 4;

memcpy(&longval, hdr, 4);
longval = ntohl(longval);
printf(" ACK Num : %d\n", longval);
hdr += 4;

printf(" Header Len : %d (bytes %d)\n", HI_WORD(*hdr),
(HI_WORD(*hdr) * 4));

memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval) & 0x3F;
printf(" Flags : ");
if (shortval & 0x20)
printf("URG ");
if (shortval & 0x10)
printf("ACK ");
if (shortval & 0x08)
printf("PSH ");
if (shortval & 0x04)
printf("RST ");
if (shortval & 0x02)
printf("SYN ");
if (shortval & 0x01)
printf("FIN ");
printf("\n");
hdr += 2;

memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval);
printf(" Window size: %d\n", shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval);
printf(" TCP Chksum : %d\n", shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
shortval = ntohs(shortval);
printf(" Urgent ptr : %d\n", shortval);

return 0;
}

[zhouyong0371]

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

//解析UDP
//
// Function: DecodeUDPHeader
//
// Description:
// This function takes a buffer which points to a UDP
// header and prints it out in a readable form.
//
int DecodeUDPHeader(WSABUF *wsabuf, DWORD iphdrlen)
{
BYTE *hdr = (BYTE *)(wsabuf->buf + iphdrlen);
unsigned short shortval,
udp_src_port,
udp_dest_port,
udp_len,
udp_chksum;

memcpy(&shortval, hdr, 2);
udp_src_port = ntohs(shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
udp_dest_port = ntohs(shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
udp_len = ntohs(shortval);
hdr += 2;

memcpy(&shortval, hdr, 2);
udp_chksum = ntohs(shortval);

printf(" UDP HEADER\n");
printf(" Source Port: %-05d | Dest Port: %-05d\n",
udp_src_port, udp_dest_port);
printf(" UDP Len: %-05d | ChkSum: 0x%08x\n",
udp_len, udp_chksum);
return 0;
}

[mqbwx]

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