net_dgrm.c

quake1 dos源代码最新版本

/*
Copyright (C) 1996-1997 Id Software, Inc.

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.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// net_dgrm.c

// This enables a simple IP banning mechanism
#ifndef __LCC__	// 2001-12-10 Compilable with LCC-Win32 by Jeff Ford
#define BAN_TEST
#endif	// 2001-12-10 Compilable with LCC-Win32 by Jeff Ford

#ifdef BAN_TEST
#if defined(_WIN32)
#include <windows.h>
#elif defined (NeXT)
#include <sys/socket.h>
#include <arpa/inet.h>
#else
#define AF_INET 		2	/* internet */
struct in_addr
{
	union
	{
		struct { unsigned char s_b1,s_b2,s_b3,s_b4; } S_un_b;
		struct { unsigned short s_w1,s_w2; } S_un_w;
		unsigned long S_addr;
	} S_un;
};
#define	s_addr	S_un.S_addr	/* can be used for most tcp & ip code */
struct sockaddr_in
{
    short			sin_family;
    unsigned short	sin_port;
	struct in_addr	sin_addr;
    char			sin_zero[8];
};
char *inet_ntoa(struct in_addr in);
unsigned long inet_addr(const char *cp);
#endif
#endif	// BAN_TEST

#include "quakedef.h"
#include "net_dgrm.h"

// these two macros are to make the code more readable
#define sfunc	net_landrivers[sock->landriver]
#define dfunc	net_landrivers[net_landriverlevel]

static int net_landriverlevel;

/* statistic counters */
int	packetsSent = 0;
int	packetsReSent = 0;
int packetsReceived = 0;
int receivedDuplicateCount = 0;
int shortPacketCount = 0;
int droppedDatagrams;

static int myDriverLevel;

struct
{
	unsigned int	length;
	unsigned int	sequence;
	byte			data[MAX_DATAGRAM];
} packetBuffer;

extern int m_return_state;
extern int m_state;
extern qboolean m_return_onerror;
extern char m_return_reason[32];


#ifdef DEBUG
char *StrAddr (struct qsockaddr *addr)
{
	static char buf[34];
	byte *p = (byte *)addr;
	int n;

	for (n = 0; n < 16; n++)
		sprintf (buf + n * 2, "%02x", *p++);
	return buf;
}
#endif


#ifdef BAN_TEST
unsigned long banAddr = 0x00000000;
unsigned long banMask = 0xffffffff;

void NET_Ban_f (void)
{
	char	addrStr [32];
	char	maskStr [32];
	void	(*print) (char *fmt, ...);

	if (cmd_source == src_command)
	{
		if (!sv.active)
		{
			Cmd_ForwardToServer ();
			return;
		}
		print = Con_Printf;
	}
	else
	{
		if (pr_global_struct->deathmatch && !host_client->privileged)
			return;
		print = SV_ClientPrintf;
	}

	switch (Cmd_Argc ())
	{
		case 1:
			if (((struct in_addr *)&banAddr)->s_addr)
			{
				strcpy(addrStr, inet_ntoa(*(struct in_addr *)&banAddr));
				strcpy(maskStr, inet_ntoa(*(struct in_addr *)&banMask));
				print("Banning %s [%s]\n", addrStr, maskStr);
			}
			else
				print("Banning not active\n");
			break;

		case 2:
			if (Q_strcasecmp(Cmd_Argv(1), "off") == 0)
				banAddr = 0x00000000;
			else
				banAddr = inet_addr(Cmd_Argv(1));
			banMask = 0xffffffff;
			break;

		case 3:
			banAddr = inet_addr(Cmd_Argv(1));
			banMask = inet_addr(Cmd_Argv(2));
			break;

		default:
			print("BAN ip_address [mask]\n");
			break;
	}
}
#endif


int Datagram_SendMessage (qsocket_t *sock, sizebuf_t *data)
{
	unsigned int	packetLen;
	unsigned int	dataLen;
	unsigned int	eom;

#ifdef DEBUG
	if (data->cursize == 0)
		Sys_Error("Datagram_SendMessage: zero length message\n");

	if (data->cursize > NET_MAXMESSAGE)
		Sys_Error("Datagram_SendMessage: message too big %u\n", data->cursize);

	if (sock->canSend == false)
		Sys_Error("SendMessage: called with canSend == false\n");
#endif

	Q_memcpy(sock->sendMessage, data->data, data->cursize);
	sock->sendMessageLength = data->cursize;

	if (data->cursize <= MAX_DATAGRAM)
	{
		dataLen = data->cursize;
		eom = NETFLAG_EOM;
	}
	else
	{
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong(packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong(sock->sendSequence++);
	Q_memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->canSend = false;

	if (sfunc.Write (sock->socket, (byte *)&packetBuffer, packetLen, &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsSent++;
	return 1;
}


int SendMessageNext (qsocket_t *sock)
{
	unsigned int	packetLen;
	unsigned int	dataLen;
	unsigned int	eom;

	if (sock->sendMessageLength <= MAX_DATAGRAM)
	{
		dataLen = sock->sendMessageLength;
		eom = NETFLAG_EOM;
	}
	else
	{
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong(packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong(sock->sendSequence++);
	Q_memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->sendNext = false;

	if (sfunc.Write (sock->socket, (byte *)&packetBuffer, packetLen, &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsSent++;
	return 1;
}


int ReSendMessage (qsocket_t *sock)
{
	unsigned int	packetLen;
	unsigned int	dataLen;
	unsigned int	eom;

	if (sock->sendMessageLength <= MAX_DATAGRAM)
	{
		dataLen = sock->sendMessageLength;
		eom = NETFLAG_EOM;
	}
	else
	{
		dataLen = MAX_DATAGRAM;
		eom = 0;
	}
	packetLen = NET_HEADERSIZE + dataLen;

	packetBuffer.length = BigLong(packetLen | (NETFLAG_DATA | eom));
	packetBuffer.sequence = BigLong(sock->sendSequence - 1);
	Q_memcpy (packetBuffer.data, sock->sendMessage, dataLen);

	sock->sendNext = false;

	if (sfunc.Write (sock->socket, (byte *)&packetBuffer, packetLen, &sock->addr) == -1)
		return -1;

	sock->lastSendTime = net_time;
	packetsReSent++;
	return 1;
}


qboolean Datagram_CanSendMessage (qsocket_t *sock)
{
	if (sock->sendNext)
		SendMessageNext (sock);

	return sock->canSend;
}


qboolean Datagram_CanSendUnreliableMessage (qsocket_t *sock)
{
	return true;
}


int Datagram_SendUnreliableMessage (qsocket_t *sock, sizebuf_t *data)
{
	int 	packetLen;

#ifdef DEBUG
	if (data->cursize == 0)
		Sys_Error("Datagram_SendUnreliableMessage: zero length message\n");

	if (data->cursize > MAX_DATAGRAM)
		Sys_Error("Datagram_SendUnreliableMessage: message too big %u\n", data->cursize);
#endif

	packetLen = NET_HEADERSIZE + data->cursize;

	packetBuffer.length = BigLong(packetLen | NETFLAG_UNRELIABLE);
	packetBuffer.sequence = BigLong(sock->unreliableSendSequence++);
	Q_memcpy (packetBuffer.data, data->data, data->cursize);

	if (sfunc.Write (sock->socket, (byte *)&packetBuffer, packetLen, &sock->addr) == -1)
		return -1;

	packetsSent++;
	return 1;
}


int	Datagram_GetMessage (qsocket_t *sock)
{
	unsigned int	length;
	unsigned int	flags;
	int				ret = 0;
	struct qsockaddr readaddr;
	unsigned int	sequence;
	unsigned int	count;

	if (!sock->canSend)
		if ((net_time - sock->lastSendTime) > 1.0)
			ReSendMessage (sock);

	while(1)
	{
		length = sfunc.Read (sock->socket, (byte *)&packetBuffer, NET_DATAGRAMSIZE, &readaddr);

//	if ((rand() & 255) > 220)
//		continue;

		if (length == 0)
			break;

		if (length == -1)
		{
			Con_Printf("Read error\n");
			return -1;
		}

		if (sfunc.AddrCompare(&readaddr, &sock->addr) != 0)
		{
#ifdef DEBUG
			Con_DPrintf("Forged packet received\n");
			Con_DPrintf("Expected: %s\n", StrAddr (&sock->addr));
			Con_DPrintf("Received: %s\n", StrAddr (&readaddr));
#endif
			continue;
		}

		if (length < NET_HEADERSIZE)
		{
			shortPacketCount++;
			continue;
		}

		length = BigLong(packetBuffer.length);
		flags = length & (~NETFLAG_LENGTH_MASK);
		length &= NETFLAG_LENGTH_MASK;

		if (flags & NETFLAG_CTL)
			continue;

		sequence = BigLong(packetBuffer.sequence);
		packetsReceived++;

		if (flags & NETFLAG_UNRELIABLE)
		{
			if (sequence < sock->unreliableReceiveSequence)
			{
				Con_DPrintf("Got a stale datagram\n");
				ret = 0;
				break;
			}
			if (sequence != sock->unreliableReceiveSequence)
			{
				count = sequence - sock->unreliableReceiveSequence;
				droppedDatagrams += count;
				Con_DPrintf("Dropped %u datagram(s)\n", count);
			}
			sock->unreliableReceiveSequence = sequence + 1;

			length -= NET_HEADERSIZE;

			SZ_Clear (&net_message);
			SZ_Write (&net_message, packetBuffer.data, length);

			ret = 2;
			break;
		}

		if (flags & NETFLAG_ACK)
		{
			if (sequence != (sock->sendSequence - 1))
			{
				Con_DPrintf("Stale ACK received\n");
				continue;
			}
			if (sequence == sock->ackSequence)
			{
				sock->ackSequence++;
				if (sock->ackSequence != sock->sendSequence)
					Con_DPrintf("ack sequencing error\n");
			}
			else
			{
				Con_DPrintf("Duplicate ACK received\n");
				continue;
			}
			sock->sendMessageLength -= MAX_DATAGRAM;
			if (sock->sendMessageLength > 0)
			{
				Q_memcpy(sock->sendMessage, sock->sendMessage+MAX_DATAGRAM, sock->sendMessageLength);
				sock->sendNext = true;
			}
			else
			{
				sock->sendMessageLength = 0;
				sock->canSend = true;
			}
			continue;
		}

		if (flags & NETFLAG_DATA)
		{
			packetBuffer.length = BigLong(NET_HEADERSIZE | NETFLAG_ACK);
			packetBuffer.sequence = BigLong(sequence);
			sfunc.Write (sock->socket, (byte *)&packetBuffer, NET_HEADERSIZE, &readaddr);

			if (sequence != sock->receiveSequence)
			{
				receivedDuplicateCount++;
				continue;
			}
			sock->receiveSequence++;

			length -= NET_HEADERSIZE;

			if (flags & NETFLAG_EOM)
			{
				SZ_Clear(&net_message);
				SZ_Write(&net_message, sock->receiveMessage, sock->receiveMessageLength);
				SZ_Write(&net_message, packetBuffer.data, length);
				sock->receiveMessageLength = 0;

				ret = 1;
				break;
			}

			Q_memcpy(sock->receiveMessage + sock->receiveMessageLength, packetBuffer.data, length);
			sock->receiveMessageLength += length;
			continue;
		}
	}

	if (sock->sendNext)
		SendMessageNext (sock);

	return ret;
}