--- quake2/game/g_svcmds.c	2018/04/24 17:58:33	1.1
+++ quake2/game/g_svcmds.c	2018/04/24 17:59:05	1.1.1.2
@@ -8,6 +8,250 @@ void	Svcmd_Test_f (void)
 }
 
 /*
+==============================================================================
+
+PACKET FILTERING
+ 
+
+You can add or remove addresses from the filter list with:
+
+addip <ip>
+removeip <ip>
+
+The ip address is specified in dot format, and any unspecified digits will match any value, so you can specify an entire class C network with "addip 192.246.40".
+
+Removeip will only remove an address specified exactly the same way.  You cannot addip a subnet, then removeip a single host.
+
+listip
+Prints the current list of filters.
+
+writeip
+Dumps "addip <ip>" commands to listip.cfg so it can be execed at a later date.  The filter lists are not saved and restored by default, because I beleive it would cause too much confusion.
+
+filterban <0 or 1>
+
+If 1 (the default), then ip addresses matching the current list will be prohibited from entering the game.  This is the default setting.
+
+If 0, then only addresses matching the list will be allowed.  This lets you easily set up a private game, or a game that only allows players from your local network.
+
+
+==============================================================================
+*/
+
+typedef struct
+{
+	unsigned	mask;
+	unsigned	compare;
+} ipfilter_t;
+
+#define	MAX_IPFILTERS	1024
+
+ipfilter_t	ipfilters[MAX_IPFILTERS];
+int			numipfilters;
+
+/*
+=================
+StringToFilter
+=================
+*/
+static qboolean StringToFilter (char *s, ipfilter_t *f)
+{
+	char	num[128];
+	int		i, j;
+	byte	b[4];
+	byte	m[4];
+	
+	for (i=0 ; i<4 ; i++)
+	{
+		b[i] = 0;
+		m[i] = 0;
+	}
+	
+	for (i=0 ; i<4 ; i++)
+	{
+		if (*s < '0' || *s > '9')
+		{
+			gi.cprintf(NULL, PRINT_HIGH, "Bad filter address: %s\n", s);
+			return false;
+		}
+		
+		j = 0;
+		while (*s >= '0' && *s <= '9')
+		{
+			num[j++] = *s++;
+		}
+		num[j] = 0;
+		b[i] = atoi(num);
+		if (b[i] != 0)
+			m[i] = 255;
+
+		if (!*s)
+			break;
+		s++;
+	}
+	
+	f->mask = *(unsigned *)m;
+	f->compare = *(unsigned *)b;
+	
+	return true;
+}
+
+/*
+=================
+SV_FilterPacket
+=================
+*/
+qboolean SV_FilterPacket (char *from)
+{
+	int		i;
+	unsigned	in;
+	byte m[4];
+	char *p;
+
+	i = 0;
+	p = from;
+	while (*p && i < 4) {
+		m[i] = 0;
+		while (*p >= '0' && *p <= '9') {
+			m[i] = m[i]*10 + (*p - '0');
+			p++;
+		}
+		if (!*p || *p == ':')
+			break;
+		i++, p++;
+	}
+	
+	in = *(unsigned *)m;
+
+	for (i=0 ; i<numipfilters ; i++)
+		if ( (in & ipfilters[i].mask) == ipfilters[i].compare)
+			return (int)filterban->value;
+
+	return (int)!filterban->value;
+}
+
+
+/*
+=================
+SV_AddIP_f
+=================
+*/
+void SVCmd_AddIP_f (void)
+{
+	int		i;
+	
+	if (gi.argc() < 3) {
+		gi.cprintf(NULL, PRINT_HIGH, "Usage:  addip <ip-mask>\n");
+		return;
+	}
+
+	for (i=0 ; i<numipfilters ; i++)
+		if (ipfilters[i].compare == 0xffffffff)
+			break;		// free spot
+	if (i == numipfilters)
+	{
+		if (numipfilters == MAX_IPFILTERS)
+		{
+			gi.cprintf (NULL, PRINT_HIGH, "IP filter list is full\n");
+			return;
+		}
+		numipfilters++;
+	}
+	
+	if (!StringToFilter (gi.argv(2), &ipfilters[i]))
+		ipfilters[i].compare = 0xffffffff;
+}
+
+/*
+=================
+SV_RemoveIP_f
+=================
+*/
+void SVCmd_RemoveIP_f (void)
+{
+	ipfilter_t	f;
+	int			i, j;
+
+	if (gi.argc() < 3) {
+		gi.cprintf(NULL, PRINT_HIGH, "Usage:  sv removeip <ip-mask>\n");
+		return;
+	}
+
+	if (!StringToFilter (gi.argv(2), &f))
+		return;
+
+	for (i=0 ; i<numipfilters ; i++)
+		if (ipfilters[i].mask == f.mask
+		&& ipfilters[i].compare == f.compare)
+		{
+			for (j=i+1 ; j<numipfilters ; j++)
+				ipfilters[j-1] = ipfilters[j];
+			numipfilters--;
+			gi.cprintf (NULL, PRINT_HIGH, "Removed.\n");
+			return;
+		}
+	gi.cprintf (NULL, PRINT_HIGH, "Didn't find %s.\n", gi.argv(2));
+}
+
+/*
+=================
+SV_ListIP_f
+=================
+*/
+void SVCmd_ListIP_f (void)
+{
+	int		i;
+	byte	b[4];
+
+	gi.cprintf (NULL, PRINT_HIGH, "Filter list:\n");
+	for (i=0 ; i<numipfilters ; i++)
+	{
+		*(unsigned *)b = ipfilters[i].compare;
+		gi.cprintf (NULL, PRINT_HIGH, "%3i.%3i.%3i.%3i\n", b[0], b[1], b[2], b[3]);
+	}
+}
+
+/*
+=================
+SV_WriteIP_f
+=================
+*/
+void SVCmd_WriteIP_f (void)
+{
+	FILE	*f;
+	char	name[MAX_OSPATH];
+	byte	b[4];
+	int		i;
+	cvar_t	*game;
+
+	game = gi.cvar("game", "", 0);
+
+	if (!*game->string)
+		sprintf (name, "%s/listip.cfg", GAMEVERSION);
+	else
+		sprintf (name, "%s/listip.cfg", game->string);
+
+	gi.cprintf (NULL, PRINT_HIGH, "Writing %s.\n", name);
+
+	f = fopen (name, "wb");
+	if (!f)
+	{
+		gi.cprintf (NULL, PRINT_HIGH, "Couldn't open %s\n", name);
+		return;
+	}
+	
+	fprintf(f, "set filterban %d\n", (int)filterban->value);
+
+	for (i=0 ; i<numipfilters ; i++)
+	{
+		*(unsigned *)b = ipfilters[i].compare;
+		fprintf (f, "sv addip %i.%i.%i.%i\n", b[0], b[1], b[2], b[3]);
+	}
+	
+	fclose (f);
+}
+
+/*
 =================
 ServerCommand
 
@@ -23,6 +267,14 @@ void	ServerCommand (void)
 	cmd = gi.argv(1);
 	if (Q_stricmp (cmd, "test") == 0)
 		Svcmd_Test_f ();
+	else if (Q_stricmp (cmd, "addip") == 0)
+		SVCmd_AddIP_f ();
+	else if (Q_stricmp (cmd, "removeip") == 0)
+		SVCmd_RemoveIP_f ();
+	else if (Q_stricmp (cmd, "listip") == 0)
+		SVCmd_ListIP_f ();
+	else if (Q_stricmp (cmd, "writeip") == 0)
+		SVCmd_WriteIP_f ();
 	else
 		gi.cprintf (NULL, PRINT_HIGH, "Unknown server command \"%s\"\n", cmd);
 }