og-odamex/master/i_net.cpp

// Emacs style mode select   -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id$
//
// Copyright (C) 2000-2006 by Sergey Makovkin (CSDoom .62)
// Copyright (C) 2006-2026 by The Odamex Team.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// DESCRIPTION:
//	Master Server communicator
//
//-----------------------------------------------------------------------------


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

#ifdef _WIN32
#include <winsock2.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#endif

#include "i_net.h"

#ifndef _WIN32
typedef int SOCKET;
#define SOCKET_ERROR -1
#define INVALID_SOCKET -1
#define closesocket close
#define ioctlsocket ioctl
#define Sleep(x) usleep(x * 1000)
#else
typedef int socklen_t;
#endif


int net_socket;
int localport;
netadr_t net_from;   // address of who sent the packet

buf_t net_message(MAX_UDP_PACKET);

//
// UDPsocket
//
SOCKET UDPsocket(void)
{
	SOCKET s;

	// allocate a socket
	s = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (s == INVALID_SOCKET)
     	printf("can't create socket\n");

	return s;
}

//
// BindToLocalPort
//
void BindToLocalPort(SOCKET s, u_short port)
{
	int v;
	struct sockaddr_in address;

	memset(&address, 0, sizeof(address));
	address.sin_family = AF_INET;
	address.sin_addr.s_addr = INADDR_ANY;
	address.sin_port = htons(port);

	v = bind(s, (sockaddr *)&address, sizeof(address));
	if (v == SOCKET_ERROR)
    	   printf("BindToPort: error\n");
}


void CloseNetwork(void)
{
	closesocket(net_socket);
#ifdef _WIN32
	WSACleanup();
#endif
}


// this is from Quake source code :)

void SockadrToNetadr(struct sockaddr_in *s, netadr_t *a)
{
	 memcpy(&(a->ip), &(s->sin_addr), sizeof(struct in_addr));
     a->port = s->sin_port;
}

void NetadrToSockadr(netadr_t *a, struct sockaddr_in *s)
{
     memset(s, 0, sizeof(*s));
     s->sin_family = AF_INET;

	 memcpy(&(s->sin_addr), &(a->ip), sizeof(struct in_addr));
     s->sin_port = a->port;
}

char *NET_AdrToString(netadr_t a, bool displayport)
{
     static char s[64];

	 if (displayport)
		snprintf(s, 64, "%i.%i.%i.%i:%i", a.ip[0], a.ip[1], a.ip[2], a.ip[3], ntohs(a.port));
	 else
		snprintf(s, 64, "%i.%i.%i.%i", a.ip[0], a.ip[1], a.ip[2], a.ip[3]);

     return s;
}

bool NET_StringToAdr(char *s, netadr_t *a)
{
     struct hostent  *h;
     struct sockaddr_in sadr;
     char *colon;
     char copy[128];


     memset(&sadr, 0, sizeof(sadr));
     sadr.sin_family = AF_INET;

     sadr.sin_port = 0;

     strcpy(copy, s);
     // strip off a trailing :port if present
     for (colon = copy ; *colon ; colon++)
          if (*colon == ':')
          {
             *colon = 0;
             sadr.sin_port = htons(atoi(colon + 1));
          }

     if (copy[0] >= '0' && copy[0] <= '9')
     {
          *(int *)&sadr.sin_addr = inet_addr(copy);
     }
     else
     {
          if (!(h = gethostbyname(copy)))
                return 0;
          *(int *)&sadr.sin_addr = *(int *)h->h_addr_list[0];
     }

     SockadrToNetadr(&sadr, a);

     return true;
}

bool NET_CompareAdr(netadr_t a, netadr_t b)
{
	if (a.ip[0] == b.ip[0] && a.ip[1] == b.ip[1] && a.ip[2] == b.ip[2] && a.ip[3] == b.ip[3] && a.port == b.port)
		return true;

	return false;
}

int NET_GetPacket(void)
{
    struct sockaddr_in from;
    socklen_t fromlen = sizeof(from);
	net_message.clear();

    int ret = recvfrom(net_socket, (char *)net_message.ptr(), net_message.maxsize(), 0, (struct sockaddr *)&from, &fromlen);

    if (ret == -1)
    {
#ifdef _WIN32
		errno = WSAGetLastError();

		if (errno == WSAEWOULDBLOCK)
			return false;
		if (errno == WSAECONNRESET)
			return false;

		if (errno == WSAEMSGSIZE)
		{
			printf("Warning: Oversize packet from %s\n", NET_AdrToString(net_from, true));
			return false;
		}

		printf("NET_GetPacket: %s", strerror(errno));
		return false;
#else
        if (errno == EWOULDBLOCK)
            return false;
        if (errno == ECONNREFUSED)
            return false;

        printf("NET_GetPacket: %s\n", strerror(errno));
        return false;
#endif
    }
    net_message.cursize = ret;
    SockadrToNetadr(&from, &net_from);

    return ret;
}

void NET_SendPacket(int length, byte *data, netadr_t to)
{
    int ret;
    struct sockaddr_in addr;

    NetadrToSockadr(&to, &addr);

    ret = sendto(net_socket, (const char*)data, length, 0, (struct sockaddr *)&addr, sizeof(addr) );

    if (ret == -1)
    {
#ifdef _WIN32
		  int err = WSAGetLastError();

		  if (err == WSAEWOULDBLOCK)
			  return;
#else
          if (errno == EWOULDBLOCK)
              return;
          if (errno == ECONNREFUSED)
              return;
          printf("NET_SendPacket: %s\n", strerror(errno));
#endif
    }
}

//
// InitNetCommon
//
void InitNetCommon(void)
{
   unsigned long _true = true;

#ifdef _WIN32
   WSADATA wsad;
   WSAStartup(0x0101, &wsad);
#endif

   net_socket = UDPsocket();
   BindToLocalPort(net_socket, localport);
   if (ioctlsocket(net_socket, FIONBIO, &_true) == -1)
       printf("UDPsocket: ioctl FIONBIO: %s", strerror(errno));

   net_message.clear();
}


void I_SetPort(netadr_t &addr, int port)
{
   addr.port = htons(port);
}