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实现双机通信的C语言代码

实现双机通信的C语言代码

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实现双机通信的C语言代码

代码要求是什么? 基本实现 ping 的功能?

ping 代码

#include

#include

#define IP_RECORD_ROUTE 0x7

#define ICMP_ECHO 8

#define ICMP_ECHOREPLY 0

#define ICMP_MIN 8 // minimum 8 byte icmp packet (just header)

#define DEF_PACKET_SIZE 32 // Default packet size

#define MAX_PACKET 60000 // Max ICMP packet size 1024

#define MAX_IP_HDR_SIZE 60 // Max IP header size w/options

typedef struct _iphdr

{

unsigned int h_len:4; // Length of the header

unsigned int version:4; // Version of IP

unsigned char tos; // Type of service

unsigned short total_len; // Total length of the packet

unsigned short ident; // Unique identifier

unsigned short frag_and_flags; // Flags

unsigned char ttl; // Time to live

unsigned char proto; // Protocol (TCP, UDP etc)

unsigned short checksum; // IP checksum

unsigned int sourceIP;

unsigned int destIP;

} IpHeader;

//

// ICMP header structure

//

typedef struct _icmphdr

{

BYTE i_type;

BYTE i_code; // Type sub code

USHORT i_cksum;

USHORT i_id;

USHORT i_seq;

// This is not the standard header, but we reserve space for time

ULONG timestamp;

} IcmpHeader;

//

// IP option header - use with socket option IP_OPTIONS

//

typedef struct _ipoptionhdr

{

unsigned char code; // Option type

unsigned char len; // Length of option hdr

unsigned char ptr; // Offset into options

unsigned long addr; // List of IP addrs

} IpOptionHeader;

//

// Function: FillICMPData

//

// Description:

// Helper function to fill in various fields for our ICMP request

//

void FillICMPData(char *icmp_data, int datasize)

{

IcmpHeader *icmp_hdr = NULL;

char *datapart = NULL;

icmp_hdr = (IcmpHeader*)(icmp_data); //+sizeof(IpHeader)

icmp_hdr->i_type = ICMP_ECHO; // Request an ICMP echo

icmp_hdr->i_code = 0;

icmp_hdr->i_id = (USHORT)GetCurrentProcessId();

icmp_hdr->i_cksum = 0;

icmp_hdr->i_seq = 0;

datapart = icmp_data + sizeof(IcmpHeader);

//

// Place some junk in the buffer

//

memset(datapart,'E', datasize - sizeof(IcmpHeader));

}

//---------------------------------------------------------------------------

USHORT checksum(USHORT *buffer, int size)

{

unsigned long cksum=0;

while (size > 1)

{

cksum += *buffer++;

size -= sizeof(USHORT);

}

if (size)

{

cksum += *(UCHAR*)buffer;

}

cksum = (cksum >> 16) + (cksum & 0xffff);

cksum += (cksum >>16);

return (USHORT)(~cksum);

}

//---------------------------------------------------------------------------

void DecodeIPOptions(char *buf, int bytes, void CALLBACK (*pDis)(const char* szMes))

{

IpOptionHeader *ipopt = NULL;

IN_ADDR inaddr;

int i;

HOSTENT *host = NULL;

char szMesBuffer;

ipopt = (IpOptionHeader *)(buf + 20);

if (pDis != NULL)

{

pDis("RR: ");

}

for(i = 0; i < (ipopt->ptr / 4) - 1; i++)

{

inaddr.S_un.S_addr = ipopt->addr[i];

if (i != 0)

{

if (pDis != NULL)

{

pDis(" ");

}

}

host = gethostbyaddr((char *)&inaddr.S_un.S_addr, sizeof(inaddr.S_un.S_addr), AF_INET);

if (host)

{

if (pDis != NULL)

{

wsprintf(szMesBuffer, "(%-15s) %s", inet_ntoa(inaddr), host->h_name);

pDis(szMesBuffer);

}

}

else

{

if (pDis != NULL)

{

wsprintf(szMesBuffer, "(%-15s)", inet_ntoa(inaddr));

pDis(szMesBuffer);

}

}

}

return;

}

//---------------------------------------------------------------------------

int DecodeICMPHeader(char *buf, int bytes, struct sockaddr_in *from, void CALLBACK (*pDis)(const char* szMes))

{

IpHeader *iphdr = NULL;

IcmpHeader *icmphdr = NULL;

unsigned short iphdrlen;

DWORD tick;

static int icmpcount = 0;

char szMesBuffer;

char szMesBuffer1;

iphdr = (IpHeader *)buf;

// Number of 32-bit words * 4 = bytes

iphdrlen = iphdr->h_len * 4;

tick = GetTickCount();

if ((iphdrlen == MAX_IP_HDR_SIZE) && (!icmpcount))

DecodeIPOptions(buf, bytes, pDis);

if (bytes < iphdrlen + ICMP_MIN)

{

//printf("Too few bytes from %s\n", inet_ntoa(from->sin_addr));

if (pDis != NULL)

{

wsprintf(szMesBuffer, "Too few bytes from %s", inet_ntoa(from->sin_addr));

pDis(szMesBuffer);

}

}

icmphdr = (IcmpHeader*)(buf + iphdrlen);

if (icmphdr->i_type != ICMP_ECHOREPLY)

{

//printf("nonecho type %d recvd\n", icmphdr->i_type);

if (pDis != NULL)

{

wsprintf(szMesBuffer, "nonecho type %d recvd", icmphdr->i_type);

pDis(szMesBuffer);

}

return -1;

}

// Make sure this is an ICMP reply to something we sent!

//

if (icmphdr->i_id != (USHORT)GetCurrentProcessId())

{

//printf("someone else's packet!\n");

if (pDis != NULL)

{

pDis("someone else's packet!");

}

return -1;

}

//printf("%d bytes from %s:", bytes, inet_ntoa(from->sin_addr));

//printf(" icmp_seq = %d. ", icmphdr->i_seq);

//printf(" time: %d ms", tick - icmphdr->timestamp);

//printf("\n");

if (pDis != NULL)

{

wsprintf(szMesBuffer, "%d bytes from %s:", bytes, inet_ntoa(from->sin_addr));

wsprintf(szMesBuffer1, " icmp_seq = %d. ", icmphdr->i_seq);

lstrcat(szMesBuffer, szMesBuffer1);

wsprintf(szMesBuffer1, " time: %d ms", tick - icmphdr->timestamp);

lstrcat(szMesBuffer, szMesBuffer1);

wsprintf(szMesBuffer1, " TTL = %d", iphdr->ttl);

lstrcat(szMesBuffer, szMesBuffer1);

pDis(szMesBuffer);

}

icmpcount++;

return tick - icmphdr->timestamp;

}

//---------------------------------------------------------------------------

ping(const char* szTargetAddress, int iDataSize, int iTimeOut, int iTimes, bool bReply, void CALLBACK (*pDis)(const char* szMes))

{

WSADATA wsaData;

SOCKET sockRaw = INVALID_SOCKET;

struct sockaddr_in dest,

from;

int bread,

fromlen = sizeof(from),

timeout = iTimeOut,

ret;

char *icmp_data = NULL,

*recvbuf = NULL;

unsigned int addr = 0;

USHORT seq_no = 0;

struct hostent *hp = NULL;

IpHeader ip_header;

IpOptionHeader ipopt;

char szMesBuffer;

if (timeout > 3000)

timeout = 3000;

else if (timeout < 100)

timeout = 100;

if (pDis != NULL)

{

wsprintf(szMesBuffer, "ping %s with %d bytes of data:", szTargetAddress, iDataSize);

pDis(szMesBuffer);

}

if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)

{

//printf("WSAStartup() failed: %d\n", GetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "WSAStartup() failed: %d", GetLastError());

pDis(szMesBuffer);

}

return -1;

}

sockRaw = WSASocket(AF_INET, SOCK_RAW, IPPROTO_ICMP, NULL, 0, WSA_FLAG_OVERLAPPED);

if (sockRaw == INVALID_SOCKET)

{

//printf("WSASocket() failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "WSASocket() failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

// Set the send/recv timeout values

//

bread = setsockopt(sockRaw, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));

if(bread == SOCKET_ERROR)

{

//printf("setsockopt(SO_RCVTIMEO) failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "setsockopt(SO_RCVTIMEO) failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

bread = setsockopt(sockRaw, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));

if (bread == SOCKET_ERROR)

{

//printf("setsockopt(SO_SNDTIMEO) failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "setsockopt(SO_SNDTIMEO) failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

memset(&dest, 0, sizeof(dest));

//

// Resolve the endpoint's name if necessary

//

dest.sin_family = AF_INET;

if ((dest.sin_addr.s_addr = inet_addr(szTargetAddress)) == INADDR_NONE)

{

if ((hp = gethostbyname(szTargetAddress)) != NULL)

{

memcpy(&(dest.sin_addr), hp->h_addr, hp->h_length);

dest.sin_family = hp->h_addrtype;

//printf("dest.sin_addr = %s\n", inet_ntoa(dest.sin_addr));

if (pDis != NULL)

{

wsprintf(szMesBuffer, "dest.sin_addr = %s", inet_ntoa(dest.sin_addr));

pDis(szMesBuffer);

}

}

else

{

//printf("gethostbyname() failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "gethostbyname() failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

}

//

// Create the ICMP packet

//

int datasize = iDataSize;

if (datasize < 0)

datasize = DEF_PACKET_SIZE;

datasize += sizeof(IcmpHeader);

if (datasize > MAX_PACKET)

datasize = MAX_PACKET;

icmp_data = (char *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, MAX_PACKET);

recvbuf = (char *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, MAX_PACKET);

if (!icmp_data)

{

//printf("HeapAlloc() failed: %d\n", GetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "HeapAlloc() failed: %d", GetLastError());

pDis(szMesBuffer);

}

return -1;

}

//memset(icmp_data, 0, datasize); //, MAX_PACKET

FillICMPData(icmp_data, datasize);

//

// Start sending/receiving ICMP packets

//

int nCount = 0;

int iReceiveCount = 0;

if (iTimes < 2)

{

iTimes = 2;

}

while(1)

{

int bwrote;

if (nCount++ == iTimes)

break;

((IcmpHeader*)icmp_data)->i_cksum = 0;

((IcmpHeader*)icmp_data)->timestamp = GetTickCount();

((IcmpHeader*)icmp_data)->i_seq = seq_no++;

((IcmpHeader*)icmp_data)->i_cksum = checksum((USHORT*)icmp_data, datasize);

bwrote = sendto(sockRaw, icmp_data, datasize, 0, (struct sockaddr*)&dest, sizeof(dest));

if (bwrote == SOCKET_ERROR)

{

if (WSAGetLastError() == WSAETIMEDOUT)

{

//printf("timed out\n");

if (pDis != NULL)

{

wsprintf(szMesBuffer, "timed out");

pDis(szMesBuffer);

}

continue;

}

//printf("sendto() failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "sendto() failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

if (bwrote < datasize)

{

//printf("Wrote %d bytes\n", bwrote);

if (pDis != NULL)

{

wsprintf(szMesBuffer, "Wrote %d bytes", bwrote);

pDis(szMesBuffer);

}

}

bread = recvfrom(sockRaw, recvbuf, MAX_PACKET, 0, (struct sockaddr*)&from, &fromlen);

if (bread == SOCKET_ERROR)

{

if (WSAGetLastError() == WSAETIMEDOUT)

{

//printf("timed out\n");

if (pDis != NULL)

{

wsprintf(szMesBuffer, "timed out");

pDis(szMesBuffer);

}

continue;

}

//printf("recvfrom() failed: %d\n", WSAGetLastError());

if (pDis != NULL)

{

wsprintf(szMesBuffer, "recvfrom() failed: %d", WSAGetLastError());

pDis(szMesBuffer);

}

return -1;

}

DecodeICMPHeader(recvbuf, bread, &from, pDis); //return replay time ms

iReceiveCount++;

Sleep(50);//1000

}

// Cleanup

//

if (sockRaw != INVALID_SOCKET)

closesocket(sockRaw);

HeapFree(GetProcessHeap(), 0, recvbuf);

HeapFree(GetProcessHeap(), 0, icmp_data);

WSACleanup();

if (pDis != NULL && bReply)

{

pDis(" ");

nCount--;

wsprintf(szMesBuffer, "Packets: Sent = %d, Received = %d, Lost = %d (%d%s", nCount, iReceiveCount, nCount - iReceiveCount, (nCount - iReceiveCount) * 100 / nCount, "% loss)");

pDis(szMesBuffer);

pDis(" ");

}

return 0;

}

//---------------------------------------------------------------------------

调用方法:

ping(

szTargetAddress, //目标地址 //IP 或网址

iDataSize, //数据包大小

iTimeOut, //延时

iTimes, //发送次数

bReply, //是否显示信息

CALLBACK (*pDis)(const char* szMes)//显示信息的函数指针

);

void pingMessage(const char* szMes);

main()

{

ping("127.0.0.1", 32, 500, 5, true, pingMessage);

}

void pingMessage(const char* szMes)

{

printf("%s\n", szMes);

}

你下载linux内核代码就可以了。