透析ICMP协议(三): 牛刀初试之一 应用篇ping(ICMP.dll)

原理简介:
--------
这个例子演示了应用微软的ICMP.DLL怎样"ping"另一台机器. 这个DLL是没有文档话的发送ICMP回送包API接口, 也称为"pings," 就像潜水员对声纳信号的术语一样. 这段代码出自一个被一个名叫MarkG的家伙的GUI程序, 他的网页已经消失了.

ICMP.DLL API 现在在Windows平台上与微软的Winsocks工作的很好, 但是微软说更好的产品一出来他们将替换它. 微软说这个自从Windows 95时代就在用, 这些功能在在Windows 2000上仍然存在.

For more information on the ICMP.DLL API, check out sockets.com's ICMP API page.
更详细的ICMP.DLL API的信息到sockets.com的ICMP API网页获取.

具体实现:
--------
// Borland C++ 5.0: bcc32.cpp ping.cpp
// Visual C++ 5.0: cl ping.cpp wsock32.lib
//
// This sample program is hereby placed in the public domain.

#include
#include
#include
#include "icmpdefs.h"

==================ping的实现部分==================
int doit(int argc, char* argv[])
{//[bugfree] 建议将这个argc和argv的处理拿到main函数中
// 检查命令行参数
if (argc < 2) {
cerr << "usage: ping " << endl;
return 1;
}

// 装载ICMP.DLL连接库
HINSTANCE hIcmp = LoadLibrary("ICMP.DLL");
if (hIcmp == 0) {
cerr << "Unable to locate ICMP.DLL!" << endl;
return 2;
}

// 查找给定机器的IP地址信息
struct hostent* phe;
if ((phe = gethostbyname(argv[1])) == 0) {
cerr << "Could not find IP address for " << argv[1] << endl;
return 3;
}

// 定义函数三个指针类型
typedef HANDLE (WINAPI* pfnHV)(VOID);
typedef BOOL (WINAPI* pfnBH)(HANDLE);
typedef DWORD (WINAPI* pfnDHDPWPipPDD)(HANDLE, DWORD, LPVOID, WORD,
PIP_OPTION_INFORMATION, LPVOID, DWORD, DWORD); // evil, no?
//定义三个指针函数
pfnHV pIcmpCreateFile;
pfnBH pIcmpCloseHandle;
pfnDHDPWPipPDD pIcmpSendEcho;

//从ICMP.DLL中得到函数入口地址
pIcmpCreateFile = (pfnHV)GetProcAddress(hIcmp, "IcmpCreateFile");
pIcmpCloseHandle = (pfnBH)GetProcAddress(hIcmp, "IcmpCloseHandle");
pIcmpSendEcho = (pfnDHDPWPipPDD)GetProcAddress(hIcmp, "IcmpSendEcho");
if ((pIcmpCreateFile == 0) || (pIcmpCloseHandle == 0) ||
(pIcmpSendEcho == 0)) {
cerr << "Failed to get proc addr for function." << endl;
return 4;
}

// 打开ping服务
HANDLE hIP = pIcmpCreateFile();
if (hIP == INVALID_HANDLE_VALUE) {
cerr << "Unable to open ping service." << endl;
return 5;
}

// 构造ping数据包
char acPingBuffer[64];
memset(acPingBuffer, '\xAA', sizeof(acPingBuffer));
PIP_ECHO_REPLY pIpe = (PIP_ECHO_REPLY)GlobalAlloc( GMEM_FIXED | GMEM_ZEROINIT,
sizeof(IP_ECHO_REPLY) + sizeof(acPingBuffer));
if (pIpe == 0) {
cerr << "Failed to allocate global ping packet buffer." << endl;
return 6;
}
pIpe->Data = acPingBuffer;
pIpe->DataSize = sizeof(acPingBuffer);

// 发送ping数据包
DWORD dwStatus = pIcmpSendEcho(hIP, *((DWORD*)phe->h_addr_list[0]),
acPingBuffer, sizeof(acPingBuffer), NULL, pIpe,
sizeof(IP_ECHO_REPLY) + sizeof(acPingBuffer), 5000);
if (dwStatus != 0) {
cout << "Addr: " <<
int(LOBYTE(LOWORD(pIpe->Address))) << "." <<
int(HIBYTE(LOWORD(pIpe->Address))) << "." <<
int(LOBYTE(HIWORD(pIpe->Address))) << "." <<
int(HIBYTE(HIWORD(pIpe->Address))) << ", " <<
"RTT: " << int(pIpe->RoundTripTime) << "ms, " <<
"TTL: " << int(pIpe->Options.Ttl) << endl;
}
else {
cerr << "Error obtaining info from ping packet." << endl;
}

// 关闭,回收资源
GlobalFree(pIpe);
FreeLibrary(hIcmp);
return 0;
}
==================主函数==================
int main(int argc, char* argv[])
{
WSAData wsaData;
if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) {
return 255;
}

int retval = doit(argc, argv);

WSACleanup();
return retval;
}

==================头文件==================
icmpdefs.h
//ICMP.DLL 函数中需要的结构

typedef struct {
unsigned char Ttl; // Time To Live
unsigned char Tos; // Type Of Service
unsigned char Flags; // IP header flags
unsigned char OptionsSize; // Size in bytes of options data
unsigned char *OptionsData; // Pointer to options data
} IP_OPTION_INFORMATION, * PIP_OPTION_INFORMATION;

typedef struct {
DWORD Address; // Replying address
unsigned long Status; // Reply status
unsigned long RoundTripTime; // RTT in milliseconds
unsigned short DataSize; // Echo data size
unsigned short Reserved; // Reserved for system use
void *Data; // Pointer to the echo data
IP_OPTION_INFORMATION Options; // Reply options
} IP_ECHO_REPLY, * PIP_ECHO_REPLY;

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