/************************************************************************
 *   Unreal Internet Relay Chat Daemon, src/parse.c
 *   Copyright (C) 1990 Jarkko Oikarinen and
 *                      University of Oulu, Computing Center
 *
 *   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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* -- Jto -- 03 Jun 1990
 * Changed the order of defines...
 */

#ifndef CLEAN_COMPILE
static char sccsid[] =
    "@(#)parse.c	2.33 1/30/94 (C) 1988 University of Oulu, \
Computing Center and Jarkko Oikarinen";
#endif
#include <string.h>
#include "struct.h"
#include "common.h"

ID_Copyright
    ("(C) 1988 University of Oulu, Computing Center and Jarkko Oikarinen");
ID_Notes("2.33 1/30/94");
#undef RAWDEBUG

char backupbuf[8192];

#define MSGTAB
#include "msg.h"
#undef MSGTAB
#include "sys.h"
#include "numeric.h"
#include "h.h"
#include "proto.h"

/*
 * NOTE: parse() should not be called recursively by other functions!
 */
extern int lifesux;
static char *para[MAXPARA + 1];

static char sender[HOSTLEN + 1];
static int cancel_clients(aClient *, aClient *, char *);
static void remove_unknown(aClient *, char *);
static char nsprefix = 0;
/*
**  Find a client (server or user) by name.
**
**  *Note*
**	Semantics of this function has been changed from
**	the old. 'name' is now assumed to be a null terminated
**	string and the search is the for server and user.
*/
aClient inline *find_client(char *name, aClient *cptr)
{

	if (name)
	{
		cptr = hash_find_client(name, cptr);
	}
	return cptr;
}

aClient inline *find_nickserv(char *name, aClient *cptr)
{
	if (name)
		cptr = hash_find_nickserver(name, cptr);

	return cptr;
}


/*
**  Find server by name.
**
**	This implementation assumes that server and user names
**	are unique, no user can have a server name and vice versa.
**	One should maintain separate lists for users and servers,
**	if this restriction is removed.
**
**  *Note*
**	Semantics of this function has been changed from
**	the old. 'name' is now assumed to be a null terminated
**	string.
*/
aClient inline *find_server(char *name, aClient *cptr)
{
	if (name)
	{
		cptr = hash_find_server(name, cptr);
	}
	return cptr;
}


aClient inline *find_name(char *name, aClient *cptr)
{
	aClient *c2ptr = cptr;

	if (!collapse(name))
		return c2ptr;

	if ((c2ptr = hash_find_server(name, cptr)))
		return (c2ptr);
	if (!index(name, '*'))
		return c2ptr;
	for (c2ptr = client; c2ptr; c2ptr = c2ptr->next)
	{
		if (!IsServer(c2ptr) && !IsMe(c2ptr))
			continue;
		if (match(name, c2ptr->name) == 0)
			break;
		if (index(c2ptr->name, '*'))
			if (match(c2ptr->name, name) == 0)
				break;
	}
	return (c2ptr ? c2ptr : cptr);
}

/*
**  Find person by (nick)name.
*/
aClient *find_person(char *name, aClient *cptr)
{
	aClient *c2ptr = cptr;

	c2ptr = find_client(name, c2ptr);

	if (c2ptr && IsClient(c2ptr) && c2ptr->user)
		return c2ptr;
	else
		return cptr;
}


void ban_flooder(aClient *cptr)
{
	int i;
	aClient *acptr;

	/* place_host_ban also takes care of removing any other clients with same host/ip */
	place_host_ban(cptr, BAN_ACT_ZLINE, "Flood from unknown connection", UNKNOWN_FLOOD_BANTIME);
	return;
}

/*
 * This routine adds fake lag if needed.
 */
inline void parse_addlag(aClient *cptr, int cmdbytes)
{
	if (!IsServer(cptr) && 
#ifdef NO_FAKE_LAG_FOR_LOCOPS	
	!IsAnOper(cptr))
#else
	!IsOper(cptr))
#endif		
	{
		cptr->since += (1 + cmdbytes/90);
	}		
}

/*
 * parse a buffer.
 *
 * NOTE: parse() should not be called recusively by any other fucntions!
 */
int  parse(aClient *cptr, char *buffer, char *bufend)
{
	aClient *from = cptr;
	char *ch, *s;
	int  len, i, numeric = 0, paramcount, noprefix = 0;
#ifdef DEBUGMODE
	time_t then, ticks;
	int  retval;
#endif
	aCommand *cmptr = NULL;

	Debug((DEBUG_ERROR, "Parsing: %s (from %s)", buffer,
	    (*cptr->name ? cptr->name : "*")));
	if (IsDead(cptr))
		return 0;

	if ((cptr->receiveK >= UNKNOWN_FLOOD_AMOUNT) && IsUnknown(cptr))
	{
		sendto_snomask(SNO_FLOOD, "Flood from unknown connection %s detected",
			cptr->sockhost);
		ban_flooder(cptr);
		return FLUSH_BUFFER;
	}

	/* this call is a bit obsolete? - takes up CPU */
	backupbuf[0] = '\0';
	strcpy(backupbuf, buffer);
	s = sender;
	*s = '\0';
	for (ch = buffer; *ch == ' '; ch++)
		;
	para[0] = from->name;
	if (*ch == ':' || *ch == '@')
	{
		if (*ch == '@')
			nsprefix = 1;
		else
			nsprefix = 0;
		/*
		   ** Copy the prefix to 'sender' assuming it terminates
		   ** with SPACE (or NULL, which is an error, though).
		 */
		for (++ch, i = 0; *ch && *ch != ' '; ++ch)
			if (s < (sender + sizeof(sender) - 1))
				*s++ = *ch;	/* leave room for NULL */
		*s = '\0';
		/*
		   ** Actually, only messages coming from servers can have
		   ** the prefix--prefix silently ignored, if coming from
		   ** a user client...
		   **
		   ** ...sigh, the current release "v2.2PL1" generates also
		   ** null prefixes, at least to NOTIFY messages (e.g. it
		   ** puts "sptr->nickname" as prefix from server structures
		   ** where it's null--the following will handle this case
		   ** as "no prefix" at all --msa  (": NOTICE nick ...")
		 */
		if (*sender && IsServer(cptr))
		{
			if (nsprefix)
			{
				from = (aClient *) find_server_by_base64(sender);
				if (from) 
					para[0] = from->name;
			}
				else
			{
				from = find_client(sender, (aClient *)NULL);
				if (!from || match(from->name, sender))
					from = find_server_quick(sender);
				else if (!from && index(sender, '@'))
					from = find_nickserv(sender, (aClient *)NULL);
				para[0] = sender;
			}

			/* Hmm! If the client corresponding to the
			 * prefix is not found--what is the correct
			 * action??? Now, I will ignore the message
			 * (old IRC just let it through as if the
			 * prefix just wasn't there...) --msa
			 */

			if (!from)
			{
				Debug((DEBUG_ERROR,
				    "Unknown prefix (%s)(%s) from (%s)",
				    sender, buffer, cptr->name));
				ircstp->is_unpf++;
				remove_unknown(cptr, sender);
				return -1;
			}
			if (from->from != cptr)
			{
				ircstp->is_wrdi++;
				Debug((DEBUG_ERROR,
				    "Message (%s) coming from (%s)",
				    buffer, cptr->name));
				return cancel_clients(cptr, from, ch);
			}
		}
		while (*ch == ' ')
			ch++;
	}
	else
		noprefix = 1;
	if (*ch == '\0')
	{
		ircstp->is_empt++;
		Debug((DEBUG_NOTICE, "Empty message from host %s:%s",
		    cptr->name, from->name));
		return (-1);
	}
	/*
	   ** Extract the command code from the packet.  Point s to the end
	   ** of the command code and calculate the length using pointer
	   ** arithmetic.  Note: only need length for numerics and *all*
	   ** numerics must have paramters and thus a space after the command
	   ** code. -avalon
	 */
	s = (char *)index(ch, ' ');	/* s -> End of the command code */
	len = (s) ? (s - ch) : 0;
	if (len == 3 &&
	    isdigit(*ch) && isdigit(*(ch + 1)) && isdigit(*(ch + 2)))
	{
		cmptr = NULL;
		numeric = (*ch - '0') * 100 + (*(ch + 1) - '0') * 10
		    + (*(ch + 2) - '0');
		paramcount = MAXPARA;
		ircstp->is_num++;
	}
	else
	{
		int flags = 0;
		int bytes = bufend - ch;
		if (s)
			*s++ = '\0';
		if (!IsRegistered(from))
			flags |= M_UNREGISTERED;
		if (IsPerson(from))
			flags |= M_USER;
		if (IsServer(from))
			flags |= M_SERVER;
		if (IsShunned(from))
			flags |= M_SHUN;
		if (IsVirus(from))
			flags |= M_VIRUS;
		cmptr = find_Command(ch, IsServer(cptr) ? 1 : 0, flags);
		if (!cmptr)
		{
			/*
			   ** Note: Give error message *only* to recognized
			   ** persons. It's a nightmare situation to have
			   ** two programs sending "Unknown command"'s or
			   ** equivalent to each other at full blast....
			   ** If it has got to person state, it at least
			   ** seems to be well behaving. Perhaps this message
			   ** should never be generated, though...  --msa
			   ** Hm, when is the buffer empty -- if a command
			   ** code has been found ?? -Armin
			   ** This error should indeed not be sent in case
			   ** of notices -- Syzop.
			 */
			if (!IsRegistered(cptr) && stricmp(ch, "NOTICE")) {
				sendto_one(from, ":%s %d %s :You have not registered",
				    me.name, ERR_NOTREGISTERED, ch);
				parse_addlag(cptr, bytes);
				return -1;
			}
			if (IsShunned(cptr))
				return -1;
				
			if (buffer[0] != '\0')
			{
				if (IsPerson(from))
					sendto_one(from,
					    ":%s %d %s %s :Unknown command",
					    me.name, ERR_UNKNOWNCOMMAND,
					    from->name, ch);
				Debug((DEBUG_ERROR, "Unknown (%s) from %s",
				    ch, get_client_name(cptr, TRUE)));
				parse_addlag(cptr, bytes);
			}
			ircstp->is_unco++;
			return (-1);
		}
		if (cmptr->flags != 0) { /* temporary until all commands are updated */
		if ((flags & M_USER) && !(cmptr->flags & M_USER))
		{
			sendto_one(cptr, rpl_str(ERR_NOTFORUSERS), me.name,
					from->name, cmptr->cmd);
			return -1;
		}
		if ((flags & M_SERVER) && !(cmptr->flags & M_SERVER))
			return -1;
		}
		paramcount = cmptr->parameters;
		cmptr->bytes += bytes;
		if (!(cmptr->flags & M_NOLAG))
			parse_addlag(cptr, bytes);
	}
	/*
	   ** Must the following loop really be so devious? On
	   ** surface it splits the message to parameters from
	   ** blank spaces. But, if paramcount has been reached,
	   ** the rest of the message goes into this last parameter
	   ** (about same effect as ":" has...) --msa
	 */

	/* Note initially true: s==NULL || *(s-1) == '\0' !! */

	i = 0;
	if (s)
	{
		/*
		if (paramcount > MAXPARA)
			paramcount = MAXPARA;
		We now use functions to create commands, so we can just check this 
		once when the command is created rather than each time the command
		is used -- codemastr
		*/
		for (;;)
		{
			/*
			   ** Never "FRANCE " again!! ;-) Clean
			   ** out *all* blanks.. --msa
			 */
			while (*s == ' ')
				*s++ = '\0';

			if (*s == '\0')
				break;
			if (*s == ':')
			{
				/*
				   ** The rest is single parameter--can
				   ** include blanks also.
				 */
				para[++i] = s + 1;
				break;
			}
			para[++i] = s;
			if (i >= paramcount)
				break;
			for (; *s != ' ' && *s; s++)
				;
		}
	}
	para[++i] = NULL;
	if (cmptr == NULL)
		return (do_numeric(numeric, cptr, from, i, para));
	cmptr->count++;
	if (IsRegisteredUser(cptr) && (cmptr->flags & M_RESETIDLE))
		cptr->last = TStime();

#ifndef DEBUGMODE
	if (cmptr->flags & M_ALIAS)
		return (*cmptr->func) (cptr, from, i, para, cmptr->cmd);
	else
	{
		if (!cmptr->overriders)
			return (*cmptr->func) (cptr, from, i, para);
		return (*cmptr->overridetail->func) (cmptr->overridetail, cptr, from, i, para);
	}
#else
	then = clock();
	if (cmptr->flags & M_ALIAS)
		retval = (*cmptr->func) (cptr, from, i, para, cmptr->cmd);
	else 
	{
		if (!cmptr->overriders)
			retval = (*cmptr->func) (cptr, from, i, para);
		else
			retval = (*cmptr->overridetail->func) (cmptr->overridetail, cptr, from, i, para);
	}
	if (retval != FLUSH_BUFFER)
	{
		ticks = (clock() - then);
		if (IsServer(cptr))
			cmptr->rticks += ticks;
		else
			cmptr->lticks += ticks;
		cptr->cputime += ticks;
	}

	return retval;
#endif
}

static int cancel_clients(aClient *cptr, aClient *sptr, char *cmd)
{
	/*
	 * kill all possible points that are causing confusion here,
	 * I'm not sure I've got this all right...
	 * - avalon
	 * No you didn't...
	 * - Run
	 */
	/* This little bit of code allowed paswords to nickserv to be 
	 * seen.  A definite no-no.  --Russell
	 sendto_ops("Message (%s) for %s[%s!%s@%s] from %s", cmd,
	 sptr->name, sptr->from->name, sptr->from->username,
	 sptr->from->sockhost, get_client_name(cptr, TRUE));*/
	/*
	 * Incorrect prefix for a server from some connection.  If it is a
	 * client trying to be annoying, just QUIT them, if it is a server
	 * then the same deal.
	 */
	if (IsServer(sptr) || IsMe(sptr))
	{
		/*
		 * First go at tracking down what really causes the
		 * dreaded Fake Direction error.  It should not be possible
		 * ever to happen.  Assume nothing here since this is an
		 * impossibility.
		 *
		 * Check for valid fields, then send out globops with
		 * the msg command recieved, who apperently sent it,
		 * where it came from, and where it was suppose to come
		 * from.  We send the msg command to find out if its some
		 * bug somebody found with an old command, maybe some
		 * weird thing like, /ping serverto.* serverfrom.* and on
		 * the way back, fake direction?  Don't know, maybe this
		 * will tell us.  -Cabal95
		 *
		 * Take #2 on Fake Direction.  Most of them seem to be
		 * numerics.  But sometimes its getting fake direction on
		 * SERVER msgs.. HOW??  Display the full message now to
		 * figure it out... -Cabal95
		 *
		 * Okay I give up.  Can't find it.  Seems like it will
		 * exist untill ircd is completely rewritten. :/ For now
		 * just completely ignore them.  Needs to be modified to
		 * send these messages to a special oper channel. -Cabal95
		 *
		 aClient *from;
		 char   *fromname=NULL, *sptrname=NULL, *cptrname=NULL, *s;

		 while (*cmd == ' ')
		 cmd++;
		 if (s = index(cmd, ' '))
		 *s++ = '\0';
		 if (!strcasecmp(cmd, "PRIVMSG") ||
		 !strcasecmp(cmd, "NOTICE") ||
		 !strcasecmp(cmd, "PASS"))
		 s = NULL;
		 if (sptr && sptr->name)
		 sptrname = sptr->name;
		 if (cptr && cptr->name)
		 cptrname = cptr->name;
		 if (sptr && sptr->from && sptr->from->name)
		 fromname = sptr->from->name;

		 sendto_serv_butone(NULL, ":%s GLOBOPS :"
		 "Fake Direction: Message[%s %s] from %s via %s "
		 "instead of %s (Tell Cabal95)", me.name, cmd,
		 (s ? s : ""),
		 (sptr->name!=NULL)?sptr->name:"<unknown>",
		 (cptr->name!=NULL)?cptr->name:"<unknown>",
		 (fromname!=NULL)?fromname:"<unknown>");
		 sendto_ops(
		 "Fake Direction: Message[%s %s] from %s via %s "
		 "instead of %s (Tell Cabal95)", cmd,
		 (s ? s : ""),
		 (sptr->name!=NULL)?sptr->name:"<unknown>",
		 (cptr->name!=NULL)?cptr->name:"<unknown>",
		 (fromname!=NULL)?fromname:"<unknown>");

		 * We don't drop the server anymore.  Just ignore
		 * the message and go about your business.  And hope
		 * we don't get flooded. :-)  -Cabal95
		 sendto_ops("Dropping server %s", cptr->name);
		 return exit_client(cptr, cptr, &me, "Fake Direction");
		 */
		return 0;
	}
	/*
	 * Ok, someone is trying to impose as a client and things are
	 * confused.  If we got the wrong prefix from a server, send out a
	 * kill, else just exit the lame client.
	 */
	if (IsServer(cptr))
	{
		/*
		   ** It is NOT necessary to send a KILL here...
		   ** We come here when a previous 'NICK new'
		   ** nick collided with an older nick, and was
		   ** ignored, and other messages still were on
		   ** the way (like the following USER).
		   ** We simply ignore it all, a purge will be done
		   ** automatically by the server 'cptr' as a reaction
		   ** on our 'NICK older'. --Run
		 */
		return 0;	/* On our side, nothing changed */
	}
	return exit_client(cptr, cptr, &me, "Fake prefix");
}

static void remove_unknown(aClient *cptr, char *sender)
{
	if (!IsRegistered(cptr) || IsClient(cptr))
		return;
	/*
	 * Not from a server so don't need to worry about it.
	 */
	if (!IsServer(cptr))
		return;

#ifdef DEVELOP
	sendto_ops("Killing %s (%s)", sender, backupbuf);
	return;
#endif
	/*
	 * Do kill if it came from a server because it means there is a ghost
	 * user on the other server which needs to be removed. -avalon
	 */
	if (!index(sender, '.') && !nsprefix)
		sendto_one(cptr, ":%s KILL %s :%s (%s(?) <- %s)",
		    me.name, sender, me.name, sender,
		    get_client_name(cptr, FALSE));
	else
		sendto_one(cptr, ":%s SQUIT %s :(Unknown from %s)",
		    me.name, sender, get_client_name(cptr, FALSE));
}
