2025-11-28 00:35:46 +09:00

685 lines
20 KiB
C

// Sample: IPv4/6 Multicasting using Setsockopt
//
// File:
// mcastws1.c - this file
// resolve.c - common name resolution routines
// resolve.h - header file for common name resolution routines
//
// Purpose:
// This sample illustrates IP multicasting using the Winsock 1
// method of joining and leaving an multicast group. This sample
// may be invoked as either a sender or a receiver. This sample works
// with both IPv4 and IPv6 multicasting but does not include support
// for the IPv4 source multicasting.
//
// One of the advantages of using the setsockopt over WSAJoinLeaf is
// the ability to join multiple multicast groups on a single socket
// which is not possible with WSAJoinLeaf.
//
// Also note that because we include winsock2.h we must link with
// ws2_32.lib and not with wsock32.lib.
//
// Compile:
// cl -o mcastws1 mcastws1.c resolve.c ws2_32.lib
//
// Command Line Options/Parameters
// mcastws1.exe [-s] [-m str] [-p int] [-i str] [-b str] [-l] [-n int]
// -b str Local interface to bind to
// -c Connect to multicast address before sending?
// -i str Local interface to use for the multicast join
// -j Don't join the multicast group (sender only)
// -l Disable the loopback
// -m str Multicast string address to join
// -n int Number of messages to send or receive
// -p int Port number to use
// -r Use raw sockets
// -s Act as sender; otherwise receive data
// -t int Multicast TTL
// -u Set SO_REUSEADDR on socket
// -z int Buffer size (in bytes)
//
// NOTE:
// From Network Programming for Microsoft Windows, Second Edition
// by Anthony Jones and James Ohlund. Copyright 2002.
// Reproduced by permission of Microsoft Press. All rights reserved.
//
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <stdlib.h>
// This sample uses the new getaddrinfo/getnameinfo functions which are new to
// Windows XP. To run this sample on older OSes, include the following header
// file which makes it work automagically.
#include <wspiapi.h>
#include "resolve.h"
#define MCASTADDRV4 "234.5.6.7"
#define MCASTADDRV6 "ff12::1"
#define MCASTPORT "25000"
#define BUFSIZE 1024
#define DEFAULT_COUNT 500
#define DEFAULT_TTL 8
BOOL bSender=FALSE, // Act as sender?
bConnect=FALSE, // Connect before sending?
bLoopBack=FALSE, // Loopback parameter specified?
bDontJoin=FALSE, // Specifies whether to join the multicast group
bReuseAddr=FALSE; // Set SO_REUSEADDR
int gSocketType=SOCK_DGRAM, // datagram
gProtocol=IPPROTO_UDP, // UDP
gLoopBack=0, // Disable loopback?
gCount=DEFAULT_COUNT, // Number of messages to send/receive
gTtl=DEFAULT_TTL, // Multicast TTL value
gBufferSize=BUFSIZE; // Buffer size for send/recv
char *gBindAddr=NULL, // Address to bind socket to (default is 0.0.0.0 or ::)
*gInterface=NULL, // Interface to join the multicast group on
*gMulticast=MCASTADDRV4, // Multicast group to join
*gPort=MCASTPORT; // Port number to use
//
// Function: usage
//
// Description:
// Print usage information and exit.
//
void usage(char *progname)
{
printf("usage: %s -s -m str -p int -i str -l -n int\n",
progname);
printf(" -b str String address to bind to\n");
printf(" -c Connect before sending?\n");
printf(" -i str Local interface to join groups\n");
printf(" -j Don't join the multicast group\n");
printf(" -l 0/1 Turn on/off loopback\n");
printf(" -m str Multicast address string to join\n");
printf(" -n int Number of messages to send/receive\n");
printf(" -p int Port number to use\n");
printf(" The default port is: %s\n", MCASTPORT);
printf(" -r Use raw sockets\n");
printf(" -s Act as server (send data); otherwise\n");
printf(" receive data.\n");
printf(" -t int Set multicast TTL\n");
printf(" -u Set SO_REUSEADDR\n");
printf(" -z int Size of the send/recv buffer\n");
ExitProcess(1);
}
//
// Function: ValidateArgs
//
// Description
// Parse the command line arguments and set some global flags
// depeding on the values.
//
void ValidateArgs(int argc, char **argv)
{
int i;
for(i=1; i < argc ;i++)
{
if ((argv[i][0] == '-') || (argv[i][0] == '/'))
{
switch (tolower(argv[i][1]))
{
case 'b': // Address to bind to
if (i+1 >= argc)
usage(argv[0]);
gBindAddr = argv[++i];
break;
case 'c': // Connect socket
bConnect = TRUE;
break;
case 'i': // local interface to use
if (i+1 >= argc)
usage(argv[0]);
gInterface = argv[++i];
break;
case 'j': // Don't join multicast group
bDontJoin = TRUE;
break;
case 'l': // Disable loopback?
if (i+1 >= argc)
usage(argv[0]);
bLoopBack = TRUE;
gLoopBack = atoi(argv[++i]);
break;
case 'm': // multicast group to join
if (i+1 >= argc)
usage(argv[0]);
gMulticast = argv[++i];
break;
case 'n': // Number of messages to send/recv
if (i+1 >= argc)
usage(argv[0]);
gCount = atoi(argv[++i]);
break;
case 'p': // Port number to use
if (i+1 >= argc)
usage(argv[0]);
gPort = argv[++i];
break;
case 'r': // use raw sockets
gSocketType = SOCK_RAW;
break;
case 's': // sender
bSender = TRUE;
break;
case 't': // Multicast ttl
if (i+1 >= argc)
usage(argv[0]);
gTtl = atoi(argv[++i]);
break;
case 'u':
bReuseAddr = TRUE;
break;
case 'z': // Buffer size for send/recv
if (i+1 >= argc)
usage(argv[0]);
gBufferSize = atol(argv[++i]);
break;
default:
usage(argv[0]);
break;
}
}
}
return;
}
//
// Function: JoinMulticastGroup
//
// Description:
// This function joins the multicast socket on the specified multicast
// group. The structures for IPv4 and IPv6 multicast joins are slightly
// different which requires different handlers. For IPv6 the scope-ID
// (interface index) is specified for the local interface whereas for IPv4
// the actual IPv4 address of the interface is given.
//
int JoinMulticastGroup(SOCKET s, struct addrinfo *group, struct addrinfo *iface)
{
struct ip_mreq mreqv4;
struct ipv6_mreq mreqv6;
char *optval=NULL;
int optlevel = 0,
option = 0,
optlen = 0,
rc;
rc = NO_ERROR;
if (group->ai_family == AF_INET)
{
// Setup the v4 option values and ip_mreq structure
optlevel = IPPROTO_IP;
option = IP_ADD_MEMBERSHIP;
optval = (char *)& mreqv4;
optlen = sizeof(mreqv4);
mreqv4.imr_multiaddr.s_addr = ((SOCKADDR_IN *)group->ai_addr)->sin_addr.s_addr;
mreqv4.imr_interface.s_addr = ((SOCKADDR_IN *)iface->ai_addr)->sin_addr.s_addr;
}
else if (group->ai_family == AF_INET6)
{
// Setup the v6 option values and ipv6_mreq structure
optlevel = IPPROTO_IPV6;
option = IPV6_ADD_MEMBERSHIP;
optval = (char *) &mreqv6;
optlen = sizeof(mreqv6);
mreqv6.ipv6mr_multiaddr = ((SOCKADDR_IN6 *)group->ai_addr)->sin6_addr;
mreqv6.ipv6mr_interface = ((SOCKADDR_IN6 *)iface->ai_addr)->sin6_scope_id;
}
else
{
fprintf(stderr, "Attemtping to join multicast group for invalid address family!\n");
rc = SOCKET_ERROR;
}
if (rc != SOCKET_ERROR)
{
// Join the group
rc = setsockopt(
s,
optlevel,
option,
optval,
optlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "JoinMulticastGroup: setsockopt failed: %d\n", WSAGetLastError());
}
else
{
printf("Joined group: ");
PrintAddress(group->ai_addr, (int) group->ai_addrlen);
printf("\n");
}
}
return rc;
}
//
// Function: SetSendInterface
//
// Description:
// This routine sets the send (outgoing) interface of the socket.
// Again, for v4 the IP address is used to specify the interface while
// for v6 its the scope-ID.
//
int SetSendInterface(SOCKET s, struct addrinfo *iface)
{
char *optval=NULL;
int optlevel = 0,
option = 0,
optlen = 0,
rc;
rc = NO_ERROR;
if (iface->ai_family == AF_INET)
{
// Setup the v4 option values
optlevel = IPPROTO_IP;
option = IP_MULTICAST_IF;
optval = (char *) &((SOCKADDR_IN *)iface->ai_addr)->sin_addr.s_addr;
optlen = sizeof(((SOCKADDR_IN *)iface->ai_addr)->sin_addr.s_addr);
}
else if (iface->ai_family == AF_INET6)
{
// Setup the v6 option values
optlevel = IPPROTO_IPV6;
option = IPV6_MULTICAST_IF;
optval = (char *) &((SOCKADDR_IN6 *)iface->ai_addr)->sin6_scope_id;
optlen = sizeof(((SOCKADDR_IN6 *)iface->ai_addr)->sin6_scope_id);
}
else
{
fprintf(stderr, "Attemtping to set sent interface for invalid address family!\n");
rc = SOCKET_ERROR;
}
// Set send IF
if (rc != SOCKET_ERROR)
{
// Set the send interface
rc = setsockopt(
s,
optlevel,
option,
optval,
optlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "setsockopt failed: %d\n", WSAGetLastError());
}
else
{
printf("Set sending interface to: ");
PrintAddress(iface->ai_addr, (int) iface->ai_addrlen);
printf("\n");
}
}
return rc;
}
//
// Function: SetMulticastTtl
//
// Description:
// This routine sets the multicast TTL value for the socket.
//
int SetMulticastTtl(SOCKET s, int af, int ttl)
{
char *optval=NULL;
int optlevel = 0,
option = 0,
optlen = 0,
rc;
rc = NO_ERROR;
if (af == AF_INET)
{
// Set the options for V4
optlevel = IPPROTO_IP;
option = IP_MULTICAST_TTL;
optval = (char *) &ttl;
optlen = sizeof(ttl);
}
else if (af == AF_INET6)
{
// Set the options for V6
optlevel = IPPROTO_IPV6;
option = IPV6_MULTICAST_HOPS;
optval = (char *) &ttl;
optlen = sizeof(ttl);
}
else
{
fprintf(stderr, "Attemtping to set TTL for invalid address family!\n");
rc = SOCKET_ERROR;
}
if (rc != SOCKET_ERROR)
{
// Set the TTL value
rc = setsockopt(
s,
optlevel,
option,
optval,
optlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "SetMulticastTtl: setsockopt failed: %d\n", WSAGetLastError());
}
else
{
printf("Set multicast ttl to: %d\n", ttl);
}
}
return rc;
}
//
// Function: SetMulticastLoopBack
//
// Description:
// This function enabled or disables multicast loopback. If loopback is enabled
// (and the socket is a member of the destination multicast group) then the
// data will be placed in the receive queue for the socket such that if a
// receive is posted on the socket its own data will be read. For this sample
// it doesn't really matter as if invoked as the sender, no data is read.
//
int SetMulticastLoopBack(SOCKET s, int af, int loopval)
{
char *optval=NULL;
int optlevel = 0,
option = 0,
optlen = 0,
rc;
rc = NO_ERROR;
if (af == AF_INET)
{
// Set the v4 options
optlevel = IPPROTO_IP;
option = IP_MULTICAST_LOOP;
optval = (char *) &loopval;
optlen = sizeof(loopval);
}
else if (af == AF_INET6)
{
// Set the v6 options
optlevel = IPPROTO_IPV6;
option = IPV6_MULTICAST_LOOP;
optval = (char *) &loopval;
optlen = sizeof(loopval);
}
else
{
fprintf(stderr, "Attemtping to set multicast loopback for invalid address family!\n");
rc = SOCKET_ERROR;
}
if (rc != SOCKET_ERROR)
{
// Set the multpoint loopback
rc = setsockopt(
s,
optlevel,
option,
optval,
optlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "SetMulticastLoopBack: setsockopt failed: %d\n", WSAGetLastError());
}
else
{
printf("Setting multicast loopback to: %d\n", loopval);
}
}
return rc;
}
//
// Function: main
//
// Description:
// Parse the command line arguments, load the Winsock library,
// create a socket and join the multicast group. If set as a
// sender then begin sending messages to the multicast group;
// otherwise, call recvfrom() to read messages send to the
// group.
//
int __cdecl main(int argc, char **argv)
{
WSADATA wsd;
SOCKET s=INVALID_SOCKET;
struct addrinfo *resmulti=NULL,
*resbind=NULL,
*resif=NULL;
char *buf=NULL;
int rc,
i=0;
// Parse the command line
ValidateArgs(argc, argv);
// Load Winsock
if ((rc = WSAStartup(MAKEWORD(1, 1), &wsd)) != 0)
{
fprintf(stderr, "WSAStartup failed: %d\n", rc);
return -1;
}
// Resolve the multicast address
resmulti = ResolveAddress(gMulticast, gPort, AF_UNSPEC, SOCK_DGRAM, gProtocol);
if (resmulti == NULL)
{
fprintf(stderr, "Unable to convert multicast address '%s': %d\n",
gMulticast, WSAGetLastError());
goto cleanup;
}
// Resolve the binding address
resbind = ResolveAddress(gBindAddr, (bSender ? "0" : gPort), resmulti->ai_family, resmulti->ai_socktype, resmulti->ai_protocol);
if (resbind == NULL)
{
fprintf(stderr, "Unable to convert bind address '%s': %d\n",
gBindAddr, WSAGetLastError());
goto cleanup;
}
// Resolve the multicast interface
resif = ResolveAddress(gInterface, "0", resmulti->ai_family, resmulti->ai_socktype, resmulti->ai_protocol);
if (resif == NULL)
{
fprintf(stderr, "Unable to convert interface address '%s': %d\n",
gInterface, WSAGetLastError());
goto cleanup;
}
//
// Create the socket. In Winsock 1 you don't need any special
// flags to indicate multicasting.
//
s = socket(resmulti->ai_family, resmulti->ai_socktype, resmulti->ai_protocol);
if (s == INVALID_SOCKET)
{
fprintf(stderr, "socket failed with: %d\n", WSAGetLastError());
goto cleanup;
}
if (bReuseAddr)
{
int optval;
optval = 1;
rc = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&optval, sizeof(optval));
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "setsockopt(SO_REUSEADDR) failed: %d\n", WSAGetLastError());
goto cleanup;
}
}
//
// Bind the socket to the local interface. This is done so we
// can receive data
//
rc = bind(s, resbind->ai_addr, (int) resbind->ai_addrlen);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "bind failed: %d\n", WSAGetLastError());
goto cleanup;
}
printf("Binding to ");
PrintAddress(resbind->ai_addr, (int) resbind->ai_addrlen);
printf("\n");
// Join the multicast group if specified
if (bDontJoin == FALSE)
{
rc = JoinMulticastGroup(s, resmulti, resif);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "Unable to join multicast group!\n");
goto cleanup;
}
}
// Set the send (outgoing) interface
rc = SetSendInterface(s, resif);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "Unable to set multicast send interface\n");
goto cleanup;
}
// Set the TTL to something else. The default TTL is one.
rc = SetMulticastTtl(s, resmulti->ai_family, gTtl);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "Unable to set multicast TTL\n");
goto cleanup;
}
// Disable the loopback if selected. Note that on NT4 and Win95
// you cannot disable it.
if (bLoopBack)
{
rc = SetMulticastLoopBack(s, resmulti->ai_family, gLoopBack);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "Unable to set multicast loopback flag\n");
goto cleanup;
}
}
//
// When using sendto on an IPv6 multicast socket, the scope id needs
// to be zero.
//
if ((bSender) && (resmulti->ai_family == AF_INET6))
((SOCKADDR_IN6 *)resmulti->ai_addr)->sin6_scope_id = 0;
if (bConnect)
{
rc = connect(s, resmulti->ai_addr, (int) resmulti->ai_addrlen);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "connect failed: %d\n", WSAGetLastError());
goto cleanup;
}
}
buf = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, gBufferSize);
if (buf == NULL)
{
fprintf(stderr, "HeapAlloc failed: %d\n", GetLastError());
goto cleanup;
}
if (!bSender) // receiver
{
SOCKADDR_STORAGE safrom;
int fromlen;
// Receive the specified number of messages
for(i=0; i < gCount ;i++)
{
fromlen = sizeof(safrom);
rc = recvfrom(
s,
buf,
gBufferSize,
0,
(SOCKADDR *)&safrom,
&fromlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "recvfrom failed with: %d\n", WSAGetLastError());
break;
}
printf("read %d bytes from <", rc);
PrintAddress((SOCKADDR *)&safrom, fromlen);
printf(">\n");
}
}
else // sender
{
memset(buf, '^', gBufferSize);
// Send some data
for(i=0; i < gCount ; i++)
{
rc = sendto(
s,
buf,
gBufferSize,
0,
resmulti->ai_addr,
(int) resmulti->ai_addrlen
);
if (rc == SOCKET_ERROR)
{
fprintf(stderr, "sendto failed with: %d\n", WSAGetLastError());
break;
}
printf("SENT %d bytes to ", rc);
PrintAddress(resmulti->ai_addr, (int) resmulti->ai_addrlen);
printf("\n");
Sleep(500);
}
}
cleanup:
//
// Clean up allocations and sockets
//
if (buf)
HeapFree(GetProcessHeap(), 0, buf);
if (resmulti)
freeaddrinfo(resmulti);
if (resbind)
freeaddrinfo(resbind);
if (resif)
freeaddrinfo(resif);
if (s != INVALID_SOCKET)
closesocket(s);
WSACleanup();
return 0;
}