/*
 *  ircd-ratbox: A slightly useful ircd.
 *  packet.c: Packet handlers.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development 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.
 *
 *  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
 *
 */
#include "stdinc.h"
#include "s_conf.h"
#include "s_serv.h"
#include "client.h"
#include "common.h"
#include "ircd.h"
#include "parse.h"
#include "packet.h"
#include "match.h"
#include "hook.h"
#include "send.h"

static char readBuf[READBUF_SIZE];
static void client_dopacket(struct Client *client_p, char *buffer, size_t length);


/*
 * parse_client_queued - parse client queued messages
 */
static void
parse_client_queued(struct Client *client_p)
{
    int dolen = 0;
    int checkflood = 1;

    if(IsAnyDead(client_p))
        return;

    if(IsUnknown(client_p)) {
        for (;;) {
            if(client_p->localClient->sent_parsed >= client_p->localClient->allow_read)
                break;

            dolen = rb_linebuf_get(&client_p->localClient->
                                   buf_recvq, readBuf, READBUF_SIZE,
                                   LINEBUF_COMPLETE, LINEBUF_PARSED);

            if(dolen <= 0 || IsDead(client_p))
                break;

            client_dopacket(client_p, readBuf, dolen);
            client_p->localClient->sent_parsed++;

            /* He's dead cap'n */
            if(IsAnyDead(client_p))
                return;
            /* if theyve dropped out of the unknown state, break and move
             * to the parsing for their appropriate status.  --fl
             */
            if(!IsUnknown(client_p)) {
                /* reset their flood limits, they're now
                 * graced to flood
                 */
                client_p->localClient->sent_parsed = 0;
                break;
            }

        }
    }

    if(IsAnyServer(client_p) || IsExemptFlood(client_p)) {
        while (!IsAnyDead(client_p) && (dolen = rb_linebuf_get(&client_p->localClient->buf_recvq,
                                                readBuf, READBUF_SIZE, LINEBUF_COMPLETE,
                                                LINEBUF_PARSED)) > 0) {
            client_dopacket(client_p, readBuf, dolen);
        }
    } else if(IsClient(client_p)) {

        if(IsOper(client_p) && ConfigFileEntry.no_oper_flood) {
            if (ConfigFileEntry.true_no_oper_flood)
                checkflood = -1;
            else
                checkflood = 0;
        }
        /*
         * Handle flood protection here - if we exceed our flood limit on
         * messages in this loop, we simply drop out of the loop prematurely.
         *   -- adrian
         */
        for (;;) {
            /* This flood protection works as follows:
             *
             * A client is given allow_read lines to send to the server.  Every
             * time a line is parsed, sent_parsed is increased.  sent_parsed
             * is decreased by 1 every time flood_recalc is called.
             *
             * Thus a client can 'burst' allow_read lines to the server, any
             * excess lines will be parsed one per flood_recalc() call.
             *
             * Therefore a client will be penalised more if they keep flooding,
             * as sent_parsed will always hover around the allow_read limit
             * and no 'bursts' will be permitted.
             */
            if(checkflood) {
                if(client_p->localClient->sent_parsed >= client_p->localClient->allow_read)
                    break;
            }

            /* allow opers 4 times the amount of messages as users. why 4?
             * why not. :) --fl_
             */
            else if(client_p->localClient->sent_parsed >= (4 * client_p->localClient->allow_read) && checkflood != -1)
                break;

            dolen = rb_linebuf_get(&client_p->localClient->
                                   buf_recvq, readBuf, READBUF_SIZE,
                                   LINEBUF_COMPLETE, LINEBUF_PARSED);

            if(!dolen)
                break;

            client_dopacket(client_p, readBuf, dolen);
            if(IsAnyDead(client_p))
                return;
            client_p->localClient->sent_parsed++;
        }
    }
}

/* flood_endgrace()
 *
 * marks the end of the clients grace period
 */
void
flood_endgrace(struct Client *client_p)
{
    SetFloodDone(client_p);

    /* Drop their flood limit back down */
    client_p->localClient->allow_read = MAX_FLOOD;

    /* sent_parsed could be way over MAX_FLOOD but under MAX_FLOOD_BURST,
     * so reset it.
     */
    client_p->localClient->sent_parsed = 0;
}

/*
 * flood_recalc
 *
 * recalculate the number of allowed flood lines. this should be called
 * once a second on any given client. We then attempt to flush some data.
 */
void
flood_recalc(void *unused)
{
    rb_dlink_node *ptr, *next;
    struct Client *client_p;

    RB_DLINK_FOREACH_SAFE(ptr, next, lclient_list.head) {
        client_p = ptr->data;

        if(rb_unlikely(IsMe(client_p)))
            continue;

        if(rb_unlikely(client_p->localClient == NULL))
            continue;

        if(IsFloodDone(client_p))
            client_p->localClient->sent_parsed -= 2;
        else
            client_p->localClient->sent_parsed = 0;

        if(client_p->localClient->sent_parsed < 0)
            client_p->localClient->sent_parsed = 0;

        if(--client_p->localClient->actually_read < 0)
            client_p->localClient->actually_read = 0;

        parse_client_queued(client_p);

        if(rb_unlikely(IsAnyDead(client_p)))
            continue;

    }

    RB_DLINK_FOREACH_SAFE(ptr, next, unknown_list.head) {
        client_p = ptr->data;

        if(client_p->localClient == NULL)
            continue;

        client_p->localClient->sent_parsed--;

        if(client_p->localClient->sent_parsed < 0)
            client_p->localClient->sent_parsed = 0;

        if(--client_p->localClient->actually_read < 0)
            client_p->localClient->actually_read = 0;

        parse_client_queued(client_p);
    }
}

/*
 * read_packet - Read a 'packet' of data from a connection and process it.
 */
void
read_packet(rb_fde_t * F, void *data)
{
    struct Client *client_p = data;
    struct LocalUser *lclient_p = client_p->localClient;
    int length = 0;
    int lbuf_len;

    int binary = 0;
#ifdef USE_IODEBUG_HOOKS
    hook_data_int hdata;
#endif

    while(1) {
        if(IsAnyDead(client_p))
            return;

        /*
         * Read some data. We *used to* do anti-flood protection here, but
         * I personally think it makes the code too hairy to make sane.
         *     -- adrian
         */
        length = rb_read(client_p->localClient->F, readBuf, READBUF_SIZE);

        if(length < 0) {
            if(rb_ignore_errno(errno))
                rb_setselect(client_p->localClient->F,
                             RB_SELECT_READ, read_packet, client_p);
            else
                error_exit_client(client_p, length);
            return;
        } else if(length == 0) {
            error_exit_client(client_p, length);
            return;
        }

#ifdef USE_IODEBUG_HOOKS
        hdata.client = client_p;
        hdata.arg1 = readBuf;
        hdata.arg2 = length;
        call_hook(h_iorecv_id, &hdata);
#endif

        if(client_p->localClient->lasttime < rb_current_time())
            client_p->localClient->lasttime = rb_current_time();
        client_p->flags &= ~FLAGS_PINGSENT;

        /*
         * Before we even think of parsing what we just read, stick
         * it on the end of the receive queue and do it when its
         * turn comes around.
         */
        if(IsHandshake(client_p) || IsUnknown(client_p))
            binary = 1;

        lbuf_len = rb_linebuf_parse(&client_p->localClient->buf_recvq, readBuf, length, binary);

        lclient_p->actually_read += lbuf_len;

        if(IsAnyDead(client_p))
            return;

        /* Attempt to parse what we have */
        parse_client_queued(client_p);

        if(IsAnyDead(client_p))
            return;

        /* Check to make sure we're not flooding */
        if(!IsAnyServer(client_p) &&
           (rb_linebuf_alloclen(&client_p->localClient->buf_recvq) > ConfigFileEntry.client_flood)) {
            if(!(ConfigFileEntry.no_oper_flood && IsOper(client_p))) {
                exit_client(client_p, client_p, client_p, "Excess Flood");
                return;
            }
        }

        /* bail if short read */
        if(length < READBUF_SIZE) {
            rb_setselect(client_p->localClient->F, RB_SELECT_READ, read_packet, client_p);
            return;
        }
    }
}

/*
 * client_dopacket - copy packet to client buf and parse it
 *      client_p - pointer to client structure for which the buffer data
 *             applies.
 *      buffer - pointr to the buffer containing the newly read data
 *      length - number of valid bytes of data in the buffer
 *
 * Note:
 *      It is implicitly assumed that dopacket is called only
 *      with client_p of "local" variation, which contains all the
 *      necessary fields (buffer etc..)
 */
void
client_dopacket(struct Client *client_p, char *buffer, size_t length)
{
    s_assert(client_p != NULL);
    s_assert(buffer != NULL);

    if(client_p == NULL || buffer == NULL)
        return;
    if(IsAnyDead(client_p))
        return;
    /*
     * Update messages received
     */
    ++me.localClient->receiveM;
    ++client_p->localClient->receiveM;

    /*
     * Update bytes received
     */
    client_p->localClient->receiveB += length;

    if(client_p->localClient->receiveB > 1023) {
        client_p->localClient->receiveK += (client_p->localClient->receiveB >> 10);
        client_p->localClient->receiveB &= 0x03ff;	/* 2^10 = 1024, 3ff = 1023 */
    }

    me.localClient->receiveB += length;

    if(me.localClient->receiveB > 1023) {
        me.localClient->receiveK += (me.localClient->receiveB >> 10);
        me.localClient->receiveB &= 0x03ff;
    }

    parse(client_p, buffer, buffer + length);
}
