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Socket Options and Ioctls 7 part 7

What do we have in this chapter 7 part 7?

The SIO_GET_BROADCAST_ADDRESS Program Example
Setting the SO_KEEPALIVE_VALS on a Socket Program Example

The SIO_GET_BROADCAST_ADDRESS Program Example

Create a new empty Win32 console mode application and add the project/solution name.

Winsock 2 socket options and ioctls: The SIO_GET_BROADCAST_ADDRESS program example

Add the following source code.

// Description: This sample shows how to obtain the broadcast address for a UDP socket.

// No command line arguments/parameters

// Link to ws2_32.lib

#include <winsock2.h>

#include <ws2tcpip.h>

#include <stdio.h>

// Function: main

// Description: Load Winsock, create a socket and find the broadcast address

int main(int argc, char **argv)

{

WSADATA wsd;

SOCKET s;

SOCKADDR_IN bcast;

int ret;

DWORD dwBytesRet;

// Load Winsock

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

{

printf("WSAStartup() failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSAStartup() should be fine!\n");

// Create a socket

s = WSASocket(AF_INET, SOCK_DGRAM, IPPROTO_UDP, NULL, 0, WSA_FLAG_OVERLAPPED);

if (s == INVALID_SOCKET)

{

printf("WSASocket() failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSASocket() is OK!\n");

// Call the ioctl

ret = WSAIoctl(s, SIO_GET_BROADCAST_ADDRESS, NULL, 0,&bcast, sizeof(bcast), &dwBytesRet, NULL, NULL);

if (ret == SOCKET_ERROR)

{

printf("WSAIoclt(SIO_GET_BROADCAST_ADDRESS) failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSAIoclt(SIO_GET_BROADCAST_ADDRESS) should be fine!\n");

printf("Broadcast address is: '%s'\n", inet_ntoa(bcast.sin_addr));

// Cleanup

if(closesocket(s) == 0)

printf("closesocket() should be fine!\n");

else

printf("closesocket() failed with error code %d\n", WSAGetLastError());

if(WSACleanup() == 0)

printf("WSACleanup() is OK!\n");

else

printf("WSACleanup() failed with error code %d\n", WSAGetLastError());

return 0;

}

Build and run the project.

-----------------------------------------------------------------

Winsock 2 socket options and ioctls: The SIO_GET_BROADCAST_ADDRESS program example - sample output

Setting the SO_KEEPALIVE_VALS on a Socket Program Example

Create a new empty Win32 console mode application and add the project/solution name.

Winsock 2 socket options and ioctls: Setting the SO_KEEPALIVE_VALS on a socket program example

Add the following source code.

// Description:

// This sample shows you how to set the SO_KEEPALIVE_VALS

// on a socket. This option allows you to set the keepalive

// interval on a per socket basis as opposed to the rather

// useless SO_KEEPALIVE option.

// No command line arguments

// Link to ws2_32.lib

#include <winsock2.h>

#include <ws2tcpip.h>

#include <Mstcpip.h>

#include <stdio.h>

int main(int argc, char **argv)

{

WSADATA wsd;

SOCKET s;

DWORD dwBytesRet=0;

struct tcp_keepalive alive;

// Load Winsock lib

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

{

printf("WSAStartup() failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSAStartup() should be fine!\n");

// Create a socket

s = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, 0, WSA_FLAG_OVERLAPPED);

if (s == INVALID_SOCKET)

{

printf("WSASocket() failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSASocket() is fine!\n");

// Set the keepalive values

alive.onoff = TRUE;

alive.keepalivetime = 7200000;

alive.keepaliveinterval = 6000;

if (WSAIoctl(s, SIO_KEEPALIVE_VALS, &alive, sizeof(alive), NULL, 0, &dwBytesRet, NULL, NULL) == SOCKET_ERROR)

{

printf("WSAIotcl(SIO_KEEPALIVE_VALS) failed with error code %d\n", WSAGetLastError());

return -1;

}

else

printf("WSAIotcl(SIO_KEEPALIVE_VALS) is working!\n");

printf("SIO_KEEPALIVE_VALS set:\n");

printf(" Keepalive Time = %lu\n", alive.keepalivetime);

printf(" Keepalive Interval = %lu\n", alive.keepaliveinterval);

// Cleanup

if(closesocket(s) == 0)

printf("closesocket() should be fine!\n");

else

printf("closesocket() failed with error code %d\n", WSAGetLastError());

if(WSACleanup() == 0)

printf("WSACleanup() is OK!\n");

else

printf("WSACleanup() failed with error code %d\n", WSAGetLastError());

return 0;

}

Build and run the project.

Winsock 2 socket options and ioctls: Setting the SO_KEEPALIVE_VALS on a socket program example - sample output

< SIO_GET_ATM_ADDRESS etc Example | Socket Options & IOCTLs Main | SIO_RCVALL, SIO_RCVALL_MCAST & SIO_RCVALL_IGMPMCAST Examples >