// Module Name: Ping.c
//
// Description:
// This sample illustrates how an ICMP ping app can be written
// using the SOCK_RAW socket type and IPPROTO_ICMP protocol.
// By creating a raw socket, the underlying layer does not change
// the protocol header so that when we submit the ICMP header
// nothing is changed so that the receiving end will see an
// ICMP packet. Additionally, we use the record route IP option
// to get a round trip path to the endpoint. Note that the size
// of the IP option header that records the route is limited to
// nine IP addresses.
//
// Compile:
// cl -o Ping Ping.c ws2_32.lib /Zp1
//
// Command Line Options/Parameters:
// Ping [host] [packet-size]
//
// host String name of host to ping
// packet-size Integer size of packet to send
// (smaller than 1024 bytes)
//
//#pragma pack(1)
#define IP_RECORD_ROUTE 0x7
//
// IP header structure
//
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[9]; // List of IP addrs
} IpOptionHeader;
#define DEF_PACKET_SIZE 32 // Default packet size
#define MAX_PACKET 1024 // Max ICMP packet size
#define MAX_IP_HDR_SIZE 60 // Max IP header size w/options
BOOL bRecordRoute;
int datasize;
char *lpdest;
//
// Function: usage
//
// Description:
// Print usage information
//
void usage(char *progname)
{
printf("usage: ping -r [data size]\n");
printf(" -r record route\n");
printf(" host remote machine to ping\n");
printf(" datasize can be up to 1KB\n");
ExitProcess(-1);
}
//
// 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;
datapart = icmp_data + sizeof(IcmpHeader);
//
// Place some junk in the buffer
//
memset(datapart,'E', datasize - sizeof(IcmpHeader));
}
//
// Function: checksum
//
// Description:
// This function calculates the 16-bit one's complement sum
// of the supplied buffer (ICMP) header
//
USHORT checksum(USHORT *buffer, int size)
{
unsigned long cksum=0;
//
// Function: DecodeIPOptions
//
// Description:
// If the IP option header is present, find the IP options
// within the IP header and print the record route option
// values
//
void DecodeIPOptions(char *buf, int bytes)
{
IpOptionHeader *ipopt = NULL;
IN_ADDR inaddr;
int i;
HOSTENT *host = NULL;
//
// Function: DecodeICMPHeader
//
// Description:
// The response is an IP packet. We must decode the IP header to
// locate the ICMP data.
//
void DecodeICMPHeader(char *buf, int bytes,
struct sockaddr_in *from)
{
IpHeader *iphdr = NULL;
IcmpHeader *icmphdr = NULL;
unsigned short iphdrlen;
DWORD tick;
static int icmpcount = 0;
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);
if (bytes < iphdrlen + ICMP_MIN)
{
printf("Too few bytes from %s\n",
inet_ntoa(from->sin_addr));
}
icmphdr = (IcmpHeader*)(buf + iphdrlen);
if (icmphdr->i_type != ICMP_ECHOREPLY)
{
printf("nonecho type %d recvd\n", icmphdr->i_type);
return;
}
// Make sure this is an ICMP reply to something we sent!
//
if (icmphdr->i_id != (USHORT)GetCurrentProcessId())
{
printf("someone else's packet!\n");
return ;
}
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");
for(i = 1; i < argc; i++)
{
if ((argv[0] == '-') || (argv[0] == '/'))
{
switch (tolower(argv[1]))
{
case 'r': // Record route option
bRecordRoute = TRUE;
break;
default:
usage(argv[0]);
break;
}
}
else if (isdigit(argv[0]))
datasize = atoi(argv);
else
lpdest = argv;
}
}
//
// Function: main
//
// Description:
// Setup the ICMP raw socket, and create the ICMP header. Add
// the appropriate IP option header, and start sending ICMP
// echo requests to the endpoint. For each send and receive,
// we set a timeout value so that we don't wait forever for a
// response in case the endpoint is not responding. When we
// receive a packet decode it.
//
int main(int argc, char **argv)
{
//
// WSA_FLAG_OVERLAPPED flag is required for SO_RCVTIMEO,
// SO_SNDTIMEO option. If NULL is used as last param for
// WSASocket, all I/O on the socket is synchronous, the
// internal user mode wait code never gets a chance to
// execute, and therefore kernel-mode I/O blocks forever.
// A socket created via the socket function has the over-
// lapped I/O attribute set internally. But here we need
// to use WSASocket to specify a raw socket.
//
// If you want to use timeout with a synchronous
// nonoverlapped socket created by WSASocket with last
// param set to NULL, you can set the timeout by using
// the select function, or you can use WSAEventSelect and
// set the timeout in the WSAWaitForMultipleEvents
// function.
//
sockRaw = WSASocket (AF_INET, SOCK_RAW, IPPROTO_ICMP, NULL, 0,
WSA_FLAG_OVERLAPPED);
if (sockRaw == INVALID_SOCKET)
{
printf("WSASocket() failed: %d\n", WSAGetLastError());
return -1;
}
if (bRecordRoute)
{
// Setup the IP option header to go out on every ICMP packet
//
ZeroMemory(&ipopt, sizeof(ipopt));
ipopt.code = IP_RECORD_ROUTE; // Record route option
ipopt.ptr = 4; // Point to the first addr offset
ipopt.len = 39; // Length of option header