/*
 *  ircd-ratbox: A slightly useful ircd
 *  reject.c: reject users with prejudice
 *
 *  Copyright (C) 2003 Aaron Sethman <androsyn@ratbox.org>
 *  Copyright (C) 2003-2005 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
 *  USA
 *
 */

#include "stdinc.h"
#include "client.h"
#include "s_conf.h"
#include "reject.h"
#include "s_stats.h"
#include "ircd.h"
#include "send.h"
#include "numeric.h"
#include "parse.h"
#include "hostmask.h"
#include "match.h"
#include "hash.h"

static rb_patricia_tree_t *reject_tree;
static rb_dlink_list delay_exit;
static rb_dlink_list reject_list;
static rb_dlink_list throttle_list;
static rb_patricia_tree_t *throttle_tree;
static void throttle_expires(void *unused);


typedef struct _reject_data {
    rb_dlink_node rnode;
    time_t time;
    unsigned int count;
    uint32_t mask_hashv;
} reject_t;

typedef struct _delay_data {
    rb_dlink_node node;
    rb_fde_t *F;
} delay_t;

typedef struct _throttle {
    rb_dlink_node node;
    time_t last;
    int count;
} throttle_t;

unsigned long
delay_exit_length(void)
{
    return rb_dlink_list_length(&delay_exit);
}

static void
reject_exit(void *unused)
{
    rb_dlink_node *ptr, *ptr_next;
    delay_t *ddata;
    static const char *errbuf = "ERROR :Closing Link: (*** Banned (cache))\r\n";

    RB_DLINK_FOREACH_SAFE(ptr, ptr_next, delay_exit.head) {
        ddata = ptr->data;

        rb_write(ddata->F, errbuf, strlen(errbuf));
        rb_close(ddata->F);
        rb_free(ddata);
    }

    delay_exit.head = delay_exit.tail = NULL;
    delay_exit.length = 0;
}

static void
reject_expires(void *unused)
{
    rb_dlink_node *ptr, *next;
    rb_patricia_node_t *pnode;
    reject_t *rdata;

    RB_DLINK_FOREACH_SAFE(ptr, next, reject_list.head) {
        pnode = ptr->data;
        rdata = pnode->data;

        if(rdata->time + ConfigFileEntry.reject_duration > rb_current_time())
            continue;

        rb_dlinkDelete(ptr, &reject_list);
        rb_free(rdata);
        rb_patricia_remove(reject_tree, pnode);
    }
}

void
init_reject(void)
{
    reject_tree = rb_new_patricia(PATRICIA_BITS);
    throttle_tree = rb_new_patricia(PATRICIA_BITS);
    rb_event_add("reject_exit", reject_exit, NULL, DELAYED_EXIT_TIME);
    rb_event_add("reject_expires", reject_expires, NULL, 60);
    rb_event_add("throttle_expires", throttle_expires, NULL, 10);
}

unsigned long
throttle_size(void)
{
    unsigned long count;
    rb_dlink_node *ptr;
    rb_patricia_node_t *pnode;
    throttle_t *t;

    count = 0;
    RB_DLINK_FOREACH(ptr, throttle_list.head) {
        pnode = ptr->data;
        t = pnode->data;
        if (t->count > ConfigFileEntry.throttle_count)
            count++;
    }

    return count;
}

void
add_reject(struct Client *client_p, const char *mask1, const char *mask2)
{
    rb_patricia_node_t *pnode;
    reject_t *rdata;
    uint32_t hashv;

    /* Reject is disabled */
    if(ConfigFileEntry.reject_after_count == 0 || ConfigFileEntry.reject_duration == 0)
        return;

    hashv = 0;
    if (mask1 != NULL)
        hashv ^= fnv_hash_upper((const unsigned char *)mask1, 32);
    if (mask2 != NULL)
        hashv ^= fnv_hash_upper((const unsigned char *)mask2, 32);

    if((pnode = rb_match_ip(reject_tree, (struct sockaddr *)&client_p->localClient->ip)) != NULL) {
        rdata = pnode->data;
        rdata->time = rb_current_time();
        rdata->count++;
    } else {
        int bitlen = 32;
#ifdef RB_IPV6
        if(GET_SS_FAMILY(&client_p->localClient->ip) == AF_INET6)
            bitlen = 128;
#endif
        pnode = make_and_lookup_ip(reject_tree, (struct sockaddr *)&client_p->localClient->ip, bitlen);
        pnode->data = rdata = rb_malloc(sizeof(reject_t));
        rb_dlinkAddTail(pnode, &rdata->rnode, &reject_list);
        rdata->time = rb_current_time();
        rdata->count = 1;
    }
    rdata->mask_hashv = hashv;
}

int
check_reject(rb_fde_t *F, struct sockaddr *addr)
{
    rb_patricia_node_t *pnode;
    reject_t *rdata;
    delay_t *ddata;
    /* Reject is disabled */
    if(ConfigFileEntry.reject_after_count == 0 || ConfigFileEntry.reject_duration == 0)
        return 0;

    pnode = rb_match_ip(reject_tree, addr);
    if(pnode != NULL) {
        rdata = pnode->data;

        rdata->time = rb_current_time();
        if(rdata->count > (unsigned long)ConfigFileEntry.reject_after_count) {
            ddata = rb_malloc(sizeof(delay_t));
            ServerStats.is_rej++;
            rb_setselect(F, RB_SELECT_WRITE | RB_SELECT_READ, NULL, NULL);
            ddata->F = F;
            rb_dlinkAdd(ddata, &ddata->node, &delay_exit);
            return 1;
        }
    }
    /* Caller does what it wants */
    return 0;
}

int
is_reject_ip(struct sockaddr *addr)
{
    rb_patricia_node_t *pnode;
    reject_t *rdata;
    int duration;

    /* Reject is disabled */
    if(ConfigFileEntry.reject_after_count == 0 || ConfigFileEntry.reject_duration == 0)
        return 0;

    pnode = rb_match_ip(reject_tree, addr);
    if(pnode != NULL) {
        rdata = pnode->data;

        if(rdata->count > (unsigned long)ConfigFileEntry.reject_after_count) {
            duration = rdata->time + ConfigFileEntry.reject_duration - rb_current_time();
            return duration > 0 ? duration : 1;
        }
    }
    return 0;
}

void
flush_reject(void)
{
    rb_dlink_node *ptr, *next;
    rb_patricia_node_t *pnode;
    reject_t *rdata;

    RB_DLINK_FOREACH_SAFE(ptr, next, reject_list.head) {
        pnode = ptr->data;
        rdata = pnode->data;
        rb_dlinkDelete(ptr, &reject_list);
        rb_free(rdata);
        rb_patricia_remove(reject_tree, pnode);
    }
}

int
remove_reject_ip(const char *ip)
{
    rb_patricia_node_t *pnode;

    /* Reject is disabled */
    if(ConfigFileEntry.reject_after_count == 0 || ConfigFileEntry.reject_duration == 0)
        return -1;

    if((pnode = rb_match_string(reject_tree, ip)) != NULL) {
        reject_t *rdata = pnode->data;
        rb_dlinkDelete(&rdata->rnode, &reject_list);
        rb_free(rdata);
        rb_patricia_remove(reject_tree, pnode);
        return 1;
    }
    return 0;
}

int
remove_reject_mask(const char *mask1, const char *mask2)
{
    rb_dlink_node *ptr, *next;
    rb_patricia_node_t *pnode;
    reject_t *rdata;
    uint32_t hashv;
    int n = 0;

    hashv = 0;
    if (mask1 != NULL)
        hashv ^= fnv_hash_upper((const unsigned char *)mask1, 32);
    if (mask2 != NULL)
        hashv ^= fnv_hash_upper((const unsigned char *)mask2, 32);
    RB_DLINK_FOREACH_SAFE(ptr, next, reject_list.head) {
        pnode = ptr->data;
        rdata = pnode->data;
        if (rdata->mask_hashv == hashv) {
            rb_dlinkDelete(ptr, &reject_list);
            rb_free(rdata);
            rb_patricia_remove(reject_tree, pnode);
            n++;
        }
    }
    return n;
}

int
throttle_add(struct sockaddr *addr)
{
    throttle_t *t;
    rb_patricia_node_t *pnode;

    if((pnode = rb_match_ip(throttle_tree, addr)) != NULL) {
        t = pnode->data;

        if(t->count > ConfigFileEntry.throttle_count) {
            ServerStats.is_thr++;
            return 1;
        }
        /* Stop penalizing them after they've been throttled */
        t->last = rb_current_time();
        t->count++;

    } else {
        int bitlen = 32;
#ifdef RB_IPV6
        if(GET_SS_FAMILY(addr) == AF_INET6)
            bitlen = 128;
#endif
        t = rb_malloc(sizeof(throttle_t));
        t->last = rb_current_time();
        t->count = 1;
        pnode = make_and_lookup_ip(throttle_tree, addr, bitlen);
        pnode->data = t;
        rb_dlinkAdd(pnode, &t->node, &throttle_list);
    }
    return 0;
}

int
is_throttle_ip(struct sockaddr *addr)
{
    throttle_t *t;
    rb_patricia_node_t *pnode;
    int duration;

    if((pnode = rb_match_ip(throttle_tree, addr)) != NULL) {
        t = pnode->data;
        if(t->count > ConfigFileEntry.throttle_count) {
            duration = t->last + ConfigFileEntry.throttle_duration - rb_current_time();
            return duration > 0 ? duration : 1;
        }
    }
    return 0;
}

void
flush_throttle(void)
{
    rb_dlink_node *ptr, *next;
    rb_patricia_node_t *pnode;
    throttle_t *t;

    RB_DLINK_FOREACH_SAFE(ptr, next, throttle_list.head) {
        pnode = ptr->data;
        t = pnode->data;

        rb_dlinkDelete(ptr, &throttle_list);
        rb_free(t);
        rb_patricia_remove(throttle_tree, pnode);
    }
}

static void
throttle_expires(void *unused)
{
    rb_dlink_node *ptr, *next;
    rb_patricia_node_t *pnode;
    throttle_t *t;

    RB_DLINK_FOREACH_SAFE(ptr, next, throttle_list.head) {
        pnode = ptr->data;
        t = pnode->data;

        if(t->last + ConfigFileEntry.throttle_duration > rb_current_time())
            continue;

        rb_dlinkDelete(ptr, &throttle_list);
        rb_free(t);
        rb_patricia_remove(throttle_tree, pnode);
    }
}