PeterHarding: New page: =Examples= ==Winsock 1== ===gethtttp.c===

 // // GetHTTP.cpp // // Retrieves a file using the Hyper Text Transfer Protocol // and prints its contents to stdout. //  // // Pass the ...

2008-03-06T23:50:12Z

New page: =Examples= ==Winsock 1== ===gethtttp.c=== <pre> // // GetHTTP.cpp // // Retrieves a file using the Hyper Text Transfer Protocol // and prints its contents to stdout. // // // Pass the ...

New page

=Examples=

==Winsock 1==
===gethtttp.c===

<pre>
//
// GetHTTP.cpp
//
// Retrieves a file using the Hyper Text Transfer Protocol
// and prints its contents to stdout.
//

//
// Pass the server name and full path of the file on the
// command line and redirect the output to a file. The program
// prints messages to stderr as it progresses.
//
// Example:
// GetHTTP www.idgbooks.com /index.html > index.html
//

#include <stdio.h>
#include <fcntl.h>
#include <io.h>
#include <winsock.h>

void GetHTTP(LPCSTR lpServerName, LPCSTR lpFileName);

// Helper macro for displaying errors
#define PRINTERROR(s) \
fprintf(stderr,"\n%: %d\n", s, WSAGetLastError())

////////////////////////////////////////////////////////////

void main(int argc, char **argv)
{
WORD wVersionRequested = MAKEWORD(1,1);
WSADATA wsaData;
int nRet;

//
// Check arguments
//
if (argc != 3)
{
fprintf(stderr,
"\nSyntax: GetHTTP ServerName FullPathName\n");
return;
}

//
// Initialize WinSock.dll
//
nRet = WSAStartup(wVersionRequested, &wsaData);
if (nRet)
{
fprintf(stderr,"\nWSAStartup(): %d\n", nRet);
WSACleanup();
return;
}

//
// Check WinSock version
//
if (wsaData.wVersion != wVersionRequested)
{
fprintf(stderr,"\nWinSock version not supported\n");
WSACleanup();
return;
}

//
// Set "stdout" to binary mode
// so that redirection will work
// for .gif and .jpg files
//
_setmode(_fileno(stdout), _O_BINARY);

//
// Call GetHTTP() to do all the work
//
GetHTTP(argv[1], argv[2]);

//
// Release WinSock
//
WSACleanup();
}

////////////////////////////////////////////////////////////

void GetHTTP(LPCSTR lpServerName, LPCSTR lpFileName)
{
//
// Use inet_addr() to determine if we're dealing with a name
// or an address
//
IN_ADDR iaHost;
LPHOSTENT lpHostEntry;

iaHost.s_addr = inet_addr(lpServerName);
if (iaHost.s_addr == INADDR_NONE)
{
// Wasn't an IP address string, assume it is a name
lpHostEntry = gethostbyname(lpServerName);
}
else
{
// It was a valid IP address string
lpHostEntry = gethostbyaddr((const char *)&iaHost,
sizeof(struct in_addr), AF_INET);
}
if (lpHostEntry == NULL)
{
PRINTERROR("gethostbyname()");
return;
}

//
// Create a TCP/IP stream socket
//
SOCKET Socket;

Socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (Socket == INVALID_SOCKET)
{
PRINTERROR("socket()");
return;
}

//
// Find the port number for the HTTP service on TCP
//
LPSERVENT lpServEnt;
SOCKADDR_IN saServer;

lpServEnt = getservbyname("http", "tcp");
if (lpServEnt == NULL)
saServer.sin_port = htons(80);
else
saServer.sin_port = lpServEnt->s_port;

//
// Fill in the rest of the server address structure
//
saServer.sin_family = AF_INET;
saServer.sin_addr = *((LPIN_ADDR)*lpHostEntry->h_addr_list);

//
// Connect the socket
//
int nRet;

nRet = connect(Socket, (LPSOCKADDR)&saServer, sizeof(SOCKADDR_IN));
if (nRet == SOCKET_ERROR)
{
PRINTERROR("connect()");
closesocket(Socket);
return;
}

//
// Format the HTTP request
//
char szBuffer[1024];

sprintf(szBuffer, "GET %s\n", lpFileName);
nRet = send(Socket, szBuffer, strlen(szBuffer), 0);
if (nRet == SOCKET_ERROR)
{
PRINTERROR("send()");
closesocket(Socket);
return;
}

//
// Receive the file contents and print to stdout
//
while(1)
{
// Wait to receive, nRet = NumberOfBytesReceived
nRet = recv(Socket, szBuffer, sizeof(szBuffer), 0);
if (nRet == SOCKET_ERROR)
{
PRINTERROR("recv()");
break;
}

fprintf(stderr,"\nrecv() returned %d bytes", nRet);

// Did the server close the connection?
if (nRet == 0)
break;
// Write to stdout
fwrite(szBuffer, nRet, 1, stdout);
}
closesocket(Socket);
}
</pre>

===ping.c===

<pre>
//
// PING.C -- Ping program using ICMP and RAW Sockets
//

#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>

#include "ping.h"

// Internal Functions
void Ping(LPCSTR pstrHost);
void ReportError(LPCSTR pstrFrom);
int WaitForEchoReply(SOCKET s);
u_short in_cksum(u_short *addr, int len);

// ICMP Echo Request/Reply functions
int SendEchoRequest(SOCKET, LPSOCKADDR_IN);
DWORD RecvEchoReply(SOCKET, LPSOCKADDR_IN, u_char *);

// main()
void main(int argc, char **argv)
{
WSADATA wsaData;
WORD wVersionRequested = MAKEWORD(1,1);
int nRet;

// Check arguments
if (argc != 2)
{
fprintf(stderr,"\nUsage: ping hostname\n");
return;
}

// Init WinSock
nRet = WSAStartup(wVersionRequested, &wsaData);
if (nRet)
{
fprintf(stderr,"\nError initializing WinSock\n");
return;
}

// Check version
if (wsaData.wVersion != wVersionRequested)
{
fprintf(stderr,"\nWinSock version not supported\n");
return;
}

// Go do the ping
Ping(argv[1]);

// Free WinSock
WSACleanup();
}

// Ping()
// Calls SendEchoRequest() and
// RecvEchoReply() and prints results
void Ping(LPCSTR pstrHost)
{
SOCKET rawSocket;
LPHOSTENT lpHost;
struct sockaddr_in saDest;
struct sockaddr_in saSrc;
DWORD dwTimeSent;
DWORD dwElapsed;
u_char cTTL;
int nLoop;
int nRet;

// Create a Raw socket
rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (rawSocket == SOCKET_ERROR)
{
ReportError("socket()");
return;
}

// Lookup host
lpHost = gethostbyname(pstrHost);
if (lpHost == NULL)
{
fprintf(stderr,"\nHost not found: %s\n", pstrHost);
return;
}

// Setup destination socket address
saDest.sin_addr.s_addr = *((u_long FAR *) (lpHost->h_addr));
saDest.sin_family = AF_INET;
saDest.sin_port = 0;

// Tell the user what we're doing
printf("\nPinging %s [%s] with %d bytes of data:\n",
pstrHost,
inet_ntoa(saDest.sin_addr),
REQ_DATASIZE);

// Ping multiple times
for (nLoop = 0; nLoop < 4; nLoop++)
{
// Send ICMP echo request
SendEchoRequest(rawSocket, &saDest);

// Use select() to wait for data to be received
nRet = WaitForEchoReply(rawSocket);
if (nRet == SOCKET_ERROR)
{
ReportError("select()");
break;
}
if (!nRet)
{
printf("\nTimeOut");
break;
}

// Receive reply
dwTimeSent = RecvEchoReply(rawSocket, &saSrc, &cTTL);

// Calculate elapsed time
dwElapsed = GetTickCount() - dwTimeSent;
printf("\nReply from: %s: bytes=%d time=%ldms TTL=%d",
inet_ntoa(saSrc.sin_addr),
REQ_DATASIZE,
dwElapsed,
cTTL);
}
printf("\n");
nRet = closesocket(rawSocket);
if (nRet == SOCKET_ERROR)
ReportError("closesocket()");
}

// SendEchoRequest()
// Fill in echo request header
// and send to destination
int SendEchoRequest(SOCKET s,LPSOCKADDR_IN lpstToAddr)
{
static ECHOREQUEST echoReq;
static nId = 1;
static nSeq = 1;
int nRet;

// Fill in echo request
echoReq.icmpHdr.Type = ICMP_ECHOREQ;
echoReq.icmpHdr.Code = 0;
echoReq.icmpHdr.Checksum = 0;
echoReq.icmpHdr.ID = nId++;
echoReq.icmpHdr.Seq = nSeq++;

// Fill in some data to send
for (nRet = 0; nRet < REQ_DATASIZE; nRet++)
echoReq.cData[nRet] = ' '+nRet;

// Save tick count when sent
echoReq.dwTime = GetTickCount();

// Put data in packet and compute checksum
echoReq.icmpHdr.Checksum = in_cksum((u_short *)&echoReq, sizeof(ECHOREQUEST));

// Send the echo request
nRet = sendto(s, /* socket */
(LPSTR)&echoReq, /* buffer */
sizeof(ECHOREQUEST),
0, /* flags */
(LPSOCKADDR)lpstToAddr, /* destination */
sizeof(SOCKADDR_IN)); /* address length */

if (nRet == SOCKET_ERROR)
ReportError("sendto()");
return (nRet);
}

// RecvEchoReply()
// Receive incoming data
// and parse out fields
DWORD RecvEchoReply(SOCKET s, LPSOCKADDR_IN lpsaFrom, u_char *pTTL)
{
ECHOREPLY echoReply;
int nRet;
int nAddrLen = sizeof(struct sockaddr_in);

// Receive the echo reply
nRet = recvfrom(s, // socket
(LPSTR)&echoReply, // buffer
sizeof(ECHOREPLY), // size of buffer
0, // flags
(LPSOCKADDR)lpsaFrom, // From address
&nAddrLen); // pointer to address len

// Check return value
if (nRet == SOCKET_ERROR)
ReportError("recvfrom()");

// return time sent and IP TTL
*pTTL = echoReply.ipHdr.TTL;
return(echoReply.echoRequest.dwTime);
}

// What happened?
void ReportError(LPCSTR pWhere)
{
fprintf(stderr,"\n%s error: %d\n",
WSAGetLastError());
}

// WaitForEchoReply()
// Use select() to determine when
// data is waiting to be read
int WaitForEchoReply(SOCKET s)
{
struct timeval Timeout;
fd_set readfds;

readfds.fd_count = 1;
readfds.fd_array[0] = s;
Timeout.tv_sec = 5;
Timeout.tv_usec = 0;

return(select(1, &readfds, NULL, NULL, &Timeout));
}

//
// Mike Muuss' in_cksum() function
// and his comments from the original
// ping program
//
// * Author -
// * Mike Muuss
// * U. S. Army Ballistic Research Laboratory
// * December, 1983

/*
* I N _ C K S U M
*
* Checksum routine for Internet Protocol family headers (C Version)
*
*/
u_short in_cksum(u_short *addr, int len)
{
register int nleft = len;
register u_short *w = addr;
register u_short answer;
register int sum = 0;

/*
* Our algorithm is simple, using a 32 bit accumulator (sum),
* we add sequential 16 bit words to it, and at the end, fold
* back all the carry bits from the top 16 bits into the lower
* 16 bits.
*/
while( nleft > 1 ) {
sum += *w++;
nleft -= 2;
}

/* mop up an odd byte, if necessary */
if( nleft == 1 ) {
u_short u = 0;

*(u_char *)(&u) = *(u_char *)w ;
sum += u;
}

/*
* add back carry outs from top 16 bits to low 16 bits
*/
sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
sum += (sum >> 16); /* add carry */
answer = ~sum; /* truncate to 16 bits */
return (answer);
}
</pre>

Winsock Examples - Revision history

PeterHarding: New page: =Examples= ==Winsock 1== ===gethtttp.c===
// // GetHTTP.cpp // // Retrieves a file using the Hyper Text Transfer Protocol // and prints its contents to stdout. // // // Pass the ...