IPv6-Enabled Server Code
The following code is the IP-agnostic Server.c file, which is an IPv6-enabled version of the Simples.c file.
//
// server.c - Simple TCP/UDP server using Winsock 2.2
//
// This is a part of the Microsoft<entity type="reg"/> Source Code Samples.
// Copyright 1996 - 2000 Microsoft Corporation.
// All rights reserved.
// This source code is only intended as a supplement to
// Microsoft Development Tools and/or WinHelp<entity type="reg"/> documentation.
// See these sources for detailed information regarding the
// Microsoft samples programs.
//
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <mstcpip.h>
#include <stdlib.h>
#include <stdio.h>
// Needed for the Windows 2000 IPv6 Tech Preview.
#if (_WIN32_WINNT == 0x0500)
#include <tpipv6.h>
#endif
// Link with ws2_32.lib
#pragma comment(lib, "Ws2_32.lib")
#define STRICMP _stricmp
//
// This code assumes that at the transport level, the system only supports
// one stream protocol (TCP) and one datagram protocol (UDP). Therefore,
// specifying a socket type of SOCK_STREAM is equivalent to specifying TCP
// and specifying a socket type of SOCK_DGRAM is equivalent to specifying UDP.
//
#define DEFAULT_FAMILY PF_UNSPEC // Accept either IPv4 or IPv6
#define DEFAULT_SOCKTYPE SOCK_STREAM // TCP
#define DEFAULT_PORT "5001" // Arbitrary, albiet a historical test port
#define BUFFER_SIZE 64 // Set very small for demonstration purposes
void Usage(char *ProgName)
{
fprintf(stderr, "\nSimple socket sample server program.\n");
fprintf(stderr,
"\n%s [-f family] [-t transport] [-p port] [-a address]\n\n",
ProgName);
fprintf(stderr,
" family\tOne of PF_INET, PF_INET6 or PF_UNSPEC. (default %s)\n",
(DEFAULT_FAMILY ==
PF_UNSPEC) ? "PF_UNSPEC" : ((DEFAULT_FAMILY ==
PF_INET) ? "PF_INET" : "PF_INET6"));
fprintf(stderr, " transport\tEither TCP or UDP. (default: %s)\n",
(DEFAULT_SOCKTYPE == SOCK_STREAM) ? "TCP" : "UDP");
fprintf(stderr, " port\t\tPort on which to bind. (default %s)\n",
DEFAULT_PORT);
fprintf(stderr,
" address\tIP address on which to bind. (default: unspecified address)\n");
WSACleanup();
exit(1);
}
LPSTR PrintError(int ErrorCode)
{
static char Message[1024];
// If this program was multithreaded, we'd want to use
// FORMAT_MESSAGE_ALLOCATE_BUFFER instead of a static buffer here.
// (And of course, free the buffer when we were done with it)
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS |
FORMAT_MESSAGE_MAX_WIDTH_MASK, NULL, ErrorCode,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPSTR) Message, 1024, NULL);
return Message;
}
int main(int argc, char **argv)
{
char Buffer[BUFFER_SIZE], Hostname[NI_MAXHOST];
int Family = DEFAULT_FAMILY;
int SocketType = DEFAULT_SOCKTYPE;
char *Port = DEFAULT_PORT;
char *Address = NULL;
int i, NumSocks, RetVal, FromLen, AmountRead;
// int idx;
SOCKADDR_STORAGE From;
WSADATA wsaData;
ADDRINFO Hints, *AddrInfo, *AI;
SOCKET ServSock[FD_SETSIZE];
fd_set SockSet;
// Parse arguments
if (argc > 1) {
for (i = 1; i < argc; i++) {
if ((argv[i][0] == '-') || (argv[i][0] == '/') &&
(argv[i][1] != 0) && (argv[i][2] == 0)) {
switch (tolower(argv[i][1])) {
case 'f':
if (!argv[i + 1])
Usage(argv[0]);
if (!STRICMP(argv[i + 1], "PF_INET"))
Family = PF_INET;
else if (!STRICMP(argv[i + 1], "PF_INET6"))
Family = PF_INET6;
else if (!STRICMP(argv[i + 1], "PF_UNSPEC"))
Family = PF_UNSPEC;
else
Usage(argv[0]);
i++;
break;
case 't':
if (!argv[i + 1])
Usage(argv[0]);
if (!STRICMP(argv[i + 1], "TCP"))
SocketType = SOCK_STREAM;
else if (!STRICMP(argv[i + 1], "UDP"))
SocketType = SOCK_DGRAM;
else
Usage(argv[0]);
i++;
break;
case 'a':
if (argv[i + 1]) {
if (argv[i + 1][0] != '-') {
Address = argv[++i];
break;
}
}
Usage(argv[0]);
break;
case 'p':
if (argv[i + 1]) {
if (argv[i + 1][0] != '-') {
Port = argv[++i];
break;
}
}
Usage(argv[0]);
break;
default:
Usage(argv[0]);
break;
}
} else
Usage(argv[0]);
}
}
// Ask for Winsock version 2.2.
if ((RetVal = WSAStartup(MAKEWORD(2, 2), &wsaData)) != 0) {
fprintf(stderr, "WSAStartup failed with error %d: %s\n",
RetVal, PrintError(RetVal));
WSACleanup();
return -1;
}
if (Port == NULL) {
Usage(argv[0]);
}
//
// By setting the AI_PASSIVE flag in the hints to getaddrinfo, we're
// indicating that we intend to use the resulting address(es) to bind
// to a socket(s) for accepting incoming connections. This means that
// when the Address parameter is NULL, getaddrinfo will return one
// entry per allowed protocol family containing the unspecified address
// for that family.
//
memset(&Hints, 0, sizeof (Hints));
Hints.ai_family = Family;
Hints.ai_socktype = SocketType;
Hints.ai_flags = AI_NUMERICHOST | AI_PASSIVE;
RetVal = getaddrinfo(Address, Port, &Hints, &AddrInfo);
if (RetVal != 0) {
fprintf(stderr, "getaddrinfo failed with error %d: %s\n",
RetVal, gai_strerror(RetVal));
WSACleanup();
return -1;
}
//
// For each address getaddrinfo returned, we create a new socket,
// bind that address to it, and create a queue to listen on.
//
for (i = 0, AI = AddrInfo; AI != NULL; AI = AI->ai_next) {
// Highly unlikely, but check anyway.
if (i == FD_SETSIZE) {
printf("getaddrinfo returned more addresses than we could use.\n");
break;
}
// This example only supports PF_INET and PF_INET6.
if ((AI->ai_family != PF_INET) && (AI->ai_family != PF_INET6))
continue;
// Open a socket with the correct address family for this address.
ServSock[i] = socket(AI->ai_family, AI->ai_socktype, AI->ai_protocol);
if (ServSock[i] == INVALID_SOCKET) {
fprintf(stderr, "socket() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
continue;
}
if ((AI->ai_family == PF_INET6) &&
IN6_IS_ADDR_LINKLOCAL((IN6_ADDR *) INETADDR_ADDRESS(AI->ai_addr)) &&
(((SOCKADDR_IN6 *) (AI->ai_addr))->sin6_scope_id == 0)
) {
fprintf(stderr,
"IPv6 link local addresses should specify a scope ID!\n");
}
//
// bind() associates a local address and port combination
// with the socket just created. This is most useful when
// the application is a server that has a well-known port
// that clients know about in advance.
//
if (bind(ServSock[i], AI->ai_addr, (int) AI->ai_addrlen) == SOCKET_ERROR) {
fprintf(stderr, "bind() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
closesocket(ServSock[i]);
continue;
}
//
// So far, everything we did was applicable to TCP as well as UDP.
// However, there are certain fundamental differences between stream
// protocols such as TCP and datagram protocols such as UDP.
//
// Only connection orientated sockets, for example those of type
// SOCK_STREAM, can listen() for incoming connections.
//
if (SocketType == SOCK_STREAM) {
if (listen(ServSock[i], 5) == SOCKET_ERROR) {
fprintf(stderr, "listen() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
closesocket(ServSock[i]);
continue;
}
}
printf("'Listening' on port %s, protocol %s, protocol family %s\n",
Port, (SocketType == SOCK_STREAM) ? "TCP" : "UDP",
(AI->ai_family == PF_INET) ? "PF_INET" : "PF_INET6");
i++;
}
freeaddrinfo(AddrInfo);
if (i == 0) {
fprintf(stderr, "Fatal error: unable to serve on any address.\n");
WSACleanup();
return -1;
}
NumSocks = i;
//
// We now put the server into an eternal loop,
// serving requests as they arrive.
//
FD_ZERO(&SockSet);
while (1) {
FromLen = sizeof (From);
//
// For connection orientated protocols, we will handle the
// packets received from a connection collectively. For datagram
// protocols, we have to handle each datagram individually.
//
//
// Check to see if we have any sockets remaining to be served
// from previous time through this loop. If not, call select()
// to wait for a connection request or a datagram to arrive.
//
for (i = 0; i < NumSocks; i++) {
if (FD_ISSET(ServSock[i], &SockSet))
break;
}
if (i == NumSocks) {
for (i = 0; i < NumSocks; i++)
FD_SET(ServSock[i], &SockSet);
if (select(NumSocks, &SockSet, 0, 0, 0) == SOCKET_ERROR) {
fprintf(stderr, "select() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
WSACleanup();
return -1;
}
}
for (i = 0; i < NumSocks; i++) {
if (FD_ISSET(ServSock[i], &SockSet)) {
FD_CLR(ServSock[i], &SockSet);
break;
}
}
if (SocketType == SOCK_STREAM) {
SOCKET ConnSock;
//
// Since this socket was returned by the select(), we know we
// have a connection waiting and that this accept() won't block.
//
ConnSock = accept(ServSock[i], (LPSOCKADDR) & From, &FromLen);
if (ConnSock == INVALID_SOCKET) {
fprintf(stderr, "accept() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
WSACleanup();
return -1;
}
if (getnameinfo((LPSOCKADDR) & From, FromLen, Hostname,
sizeof (Hostname), NULL, 0, NI_NUMERICHOST) != 0)
strcpy_s(Hostname, NI_MAXHOST, "<unknown>");
printf("\nAccepted connection from %s\n", Hostname);
//
// This sample server only handles connections sequentially.
// To handle multiple connections simultaneously, a server
// would likely want to launch another thread or process at this
// point to handle each individual connection. Alternatively,
// it could keep a socket per connection and use select()
// on the fd_set to determine which to read from next.
//
// Here we just loop until this connection terminates.
//
while (1) {
//
// We now read in data from the client. Because TCP
// does NOT maintain message boundaries, we may recv()
// the client's data grouped differently than it was
// sent. Since all this server does is echo the data it
// receives back to the client, we don't need to concern
// ourselves about message boundaries. But it does mean
// that the message data we print for a particular recv()
// below may contain more or less data than was contained
// in a particular client send().
//
AmountRead = recv(ConnSock, Buffer, sizeof (Buffer), 0);
if (AmountRead == SOCKET_ERROR) {
fprintf(stderr, "recv() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
closesocket(ConnSock);
break;
}
if (AmountRead == 0) {
printf("Client closed connection\n");
closesocket(ConnSock);
break;
}
printf("Received %d bytes from client: [%.*s]\n",
AmountRead, AmountRead, Buffer);
printf("Echoing same data back to client\n");
RetVal = send(ConnSock, Buffer, AmountRead, 0);
if (RetVal == SOCKET_ERROR) {
fprintf(stderr, "send() failed: error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
closesocket(ConnSock);
break;
}
}
} else {
//
// Since UDP maintains message boundaries, the amount of data
// we get from a recvfrom() should match exactly the amount of
// data the client sent in the corresponding sendto().
//
AmountRead = recvfrom(ServSock[i], Buffer, sizeof (Buffer), 0,
(LPSOCKADDR) & From, &FromLen);
if (AmountRead == SOCKET_ERROR) {
fprintf(stderr, "recvfrom() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
closesocket(ServSock[i]);
break;
}
if (AmountRead == 0) {
// This should never happen on an unconnected socket, but...
printf("recvfrom() returned zero, aborting\n");
closesocket(ServSock[i]);
break;
}
RetVal = getnameinfo((LPSOCKADDR) & From, FromLen, Hostname,
sizeof (Hostname), NULL, 0, NI_NUMERICHOST);
if (RetVal != 0) {
fprintf(stderr, "getnameinfo() failed with error %d: %s\n",
RetVal, PrintError(RetVal));
strcpy_s(Hostname, NI_MAXHOST, "<unknown>");
}
printf("Received a %d byte datagram from %s: [%.*s]\n",
AmountRead, Hostname, AmountRead, Buffer);
printf("Echoing same data back to client\n");
RetVal = sendto(ServSock[i], Buffer, AmountRead, 0,
(LPSOCKADDR) & From, FromLen);
if (RetVal == SOCKET_ERROR) {
fprintf(stderr, "send() failed with error %d: %s\n",
WSAGetLastError(), PrintError(WSAGetLastError()));
}
}
}
return 0;
}