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[irc/rqf/shadowircd.git] / src / hash.c

/*
 *  ircd-ratbox: A slightly useful ircd.
 *  hash.c: Maintains hashtables.
 *
 *  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
 *
 *  $Id: hash.c 1321 2006-05-13 23:49:14Z nenolod $
 */

#include "stdinc.h"
#include "ircd_defs.h"
#include "tools.h"
#include "s_conf.h"
#include "channel.h"
#include "client.h"
#include "common.h"
#include "hash.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "send.h"
#include "memory.h"
#include "msg.h"
#include "cache.h"
#include "s_newconf.h"

dlink_list *clientTable;
dlink_list *channelTable;
dlink_list *idTable;
dlink_list *resvTable;
dlink_list *hostTable;
dlink_list *helpTable;
dlink_list *ndTable;

/*
 * look in whowas.c for the missing ...[WW_MAX]; entry
 */

/*
 * Hashing.
 *
 *   The server uses a chained hash table to provide quick and efficient
 * hash table maintenance (providing the hash function works evenly over
 * the input range).  The hash table is thus not susceptible to problems
 * of filling all the buckets or the need to rehash.
 *    It is expected that the hash table would look something like this
 * during use:
 *                   +-----+    +-----+    +-----+   +-----+
 *                ---| 224 |----| 225 |----| 226 |---| 227 |---
 *                   +-----+    +-----+    +-----+   +-----+
 *                      |          |          |
 *                   +-----+    +-----+    +-----+
 *                   |  A  |    |  C  |    |  D  |
 *                   +-----+    +-----+    +-----+
 *                      |
 *                   +-----+
 *                   |  B  |
 *                   +-----+
 *
 * A - GOPbot, B - chang, C - hanuaway, D - *.mu.OZ.AU
 *
 * The order shown above is just one instant of the server. 
 *
 *
 * The hash functions currently used are based Fowler/Noll/Vo hashes
 * which work amazingly well and have a extremely low collision rate
 * For more info see http://www.isthe.com/chongo/tech/comp/fnv/index.html
 *
 * 
 */

/* init_hash()
 *
 * clears the various hashtables
 */
void
init_hash(void)
{
        clientTable = MyMalloc(sizeof(dlink_list) * U_MAX);
        idTable = MyMalloc(sizeof(dlink_list) * U_MAX);
        ndTable = MyMalloc(sizeof(dlink_list) * U_MAX);
        channelTable = MyMalloc(sizeof(dlink_list) * CH_MAX);
        hostTable = MyMalloc(sizeof(dlink_list) * HOST_MAX);
        resvTable = MyMalloc(sizeof(dlink_list) * R_MAX);
        helpTable = MyMalloc(sizeof(dlink_list) * HELP_MAX);
}

#ifndef RICER_HASHING
u_int32_t
fnv_hash_upper(const unsigned char *s, int bits)
{
        u_int32_t h = FNV1_32_INIT;

        while (*s)
        {
                h ^= ToUpper(*s++);
                h += (h<<1) + (h<<4) + (h<<7) + (h << 8) + (h << 24);
        }
        h = (h >> bits) ^ (h & ((2^bits)-1));
        return h;
}

u_int32_t
fnv_hash(const unsigned char *s, int bits)
{
        u_int32_t h = FNV1_32_INIT;

        while (*s)
        {
                h ^= *s++;
                h += (h<<1) + (h<<4) + (h<<7) + (h << 8) + (h << 24);
        }
        h = (h >> bits) ^ (h & ((2^bits)-1));
        return h;
}

u_int32_t
fnv_hash_len(const unsigned char *s, int bits, int len)
{
        u_int32_t h = FNV1_32_INIT;
        const unsigned char *x = s + len;
        while (*s && s < x)
        {
                h ^= *s++;
                h += (h<<1) + (h<<4) + (h<<7) + (h << 8) + (h << 24);
        }
        h = (h >> bits) ^ (h & ((2^bits)-1));
        return h;
}

u_int32_t
fnv_hash_upper_len(const unsigned char *s, int bits, int len)
{
        u_int32_t h = FNV1_32_INIT;
        const unsigned char *x = s + len;
        while (*s && s < x)
        {
                h ^= ToUpper(*s++);
                h += (h<<1) + (h<<4) + (h<<7) + (h << 8) + (h << 24);
        }
        h = (h >> bits) ^ (h & ((2^bits)-1));
        return h;
}
#endif

/* hash_nick()
 *
 * hashes a nickname, first converting to lowercase
 */
static u_int32_t
hash_nick(const char *name)
{
        return fnv_hash_upper((const unsigned char *) name, U_MAX_BITS);
}

/* hash_id()
 *
 * hashes an id, case is kept
 */
static u_int32_t
hash_id(const char *name)
{
        return fnv_hash((const unsigned char *) name, U_MAX_BITS);
}

/* hash_channel()
 *
 * hashes a channel name, based on first 30 chars only for efficiency
 */
static u_int32_t
hash_channel(const char *name)
{
        return fnv_hash_upper_len((const unsigned char *) name, CH_MAX_BITS, 30);
}

/* hash_hostname()
 *
 * hashes a hostname, based on first 30 chars only, as thats likely to
 * be more dynamic than rest.
 */
static u_int32_t
hash_hostname(const char *name)
{
        return fnv_hash_upper_len((const unsigned char *) name, HOST_MAX_BITS, 30);
}

/* hash_resv()
 *
 * hashes a resv channel name, based on first 30 chars only
 */
static u_int32_t
hash_resv(const char *name)
{
        return fnv_hash_upper_len((const unsigned char *) name, R_MAX_BITS, 30);
}

static unsigned int
hash_help(const char *name)
{
        unsigned int h = 0;

        while(*name)
        {
                h += (unsigned int) (ToLower(*name++) & 0xDF);
        }

        return (h % HELP_MAX);
}

/* add_to_id_hash()
 *
 * adds an entry to the id hash table
 */
void
add_to_id_hash(const char *name, struct Client *client_p)
{
        unsigned int hashv;

        if(EmptyString(name) || (client_p == NULL))
                return;

        hashv = hash_id(name);
        dlinkAddAlloc(client_p, &idTable[hashv]);
}

/* add_to_client_hash()
 *
 * adds an entry (client/server) to the client hash table
 */
void
add_to_client_hash(const char *name, struct Client *client_p)
{
        unsigned int hashv;

        s_assert(name != NULL);
        s_assert(client_p != NULL);
        if(EmptyString(name) || (client_p == NULL))
                return;

        hashv = hash_nick(name);
        dlinkAddAlloc(client_p, &clientTable[hashv]);
}

/* add_to_hostname_hash()
 *
 * adds a client entry to the hostname hash table
 */
void
add_to_hostname_hash(const char *hostname, struct Client *client_p)
{
        unsigned int hashv;

        s_assert(hostname != NULL);
        s_assert(client_p != NULL);
        if(EmptyString(hostname) || (client_p == NULL))
                return;

        hashv = hash_hostname(hostname);
        dlinkAddAlloc(client_p, &hostTable[hashv]);
}

/* add_to_resv_hash()
 *
 * adds a resv channel entry to the resv hash table
 */
void
add_to_resv_hash(const char *name, struct ConfItem *aconf)
{
        unsigned int hashv;

        s_assert(!EmptyString(name));
        s_assert(aconf != NULL);
        if(EmptyString(name) || aconf == NULL)
                return;

        hashv = hash_resv(name);
        dlinkAddAlloc(aconf, &resvTable[hashv]);
}

void
add_to_help_hash(const char *name, struct cachefile *hptr)
{
        unsigned int hashv;

        if(EmptyString(name) || hptr == NULL)
                return;

        hashv = hash_help(name);
        dlinkAddAlloc(hptr, &helpTable[hashv]);
}

void
add_to_nd_hash(const char *name, struct nd_entry *nd)
{
        nd->hashv = hash_nick(name);
        dlinkAdd(nd, &nd->hnode, &ndTable[nd->hashv]);
}

/* del_from_id_hash()
 *
 * removes an id from the id hash table
 */
void
del_from_id_hash(const char *id, struct Client *client_p)
{
        unsigned int hashv;

        s_assert(id != NULL);
        s_assert(client_p != NULL);
        if(EmptyString(id) || client_p == NULL)
                return;

        hashv = hash_id(id);
        dlinkFindDestroy(client_p, &idTable[hashv]);
}

/* del_from_client_hash()
 *
 * removes a client/server from the client hash table
 */
void
del_from_client_hash(const char *name, struct Client *client_p)
{
        unsigned int hashv;

        /* no s_asserts, this can happen when removing a client that
         * is unregistered.
         */
        if(EmptyString(name) || client_p == NULL)
                return;

        hashv = hash_nick(name);
        dlinkFindDestroy(client_p, &clientTable[hashv]);
}

/* del_from_channel_hash()
 * 
 * removes a channel from the channel hash table
 */
void
del_from_channel_hash(const char *name, struct Channel *chptr)
{
        unsigned int hashv;

        s_assert(name != NULL);
        s_assert(chptr != NULL);

        if(EmptyString(name) || chptr == NULL)
                return;

        hashv = hash_channel(name);
        dlinkFindDestroy(chptr, &channelTable[hashv]);
}

/* del_from_hostname_hash()
 *
 * removes a client entry from the hostname hash table
 */
void
del_from_hostname_hash(const char *hostname, struct Client *client_p)
{
        unsigned int hashv;

        if(hostname == NULL || client_p == NULL)
                return;

        hashv = hash_hostname(hostname);

        dlinkFindDestroy(client_p, &hostTable[hashv]);
}

/* del_from_resv_hash()
 *
 * removes a resv entry from the resv hash table
 */
void
del_from_resv_hash(const char *name, struct ConfItem *aconf)
{
        unsigned int hashv;

        s_assert(name != NULL);
        s_assert(aconf != NULL);
        if(EmptyString(name) || aconf == NULL)
                return;

        hashv = hash_resv(name);

        dlinkFindDestroy(aconf, &resvTable[hashv]);
}

void
clear_help_hash(void)
{
        dlink_node *ptr;
        dlink_node *next_ptr;
        int i;

        HASH_WALK_SAFE(i, HELP_MAX, ptr, next_ptr, helpTable)
        {
                free_cachefile(ptr->data);
                dlinkDestroy(ptr, &helpTable[i]);
        }
        HASH_WALK_END
}

/* find_id()
 *
 * finds a client entry from the id hash table
 */
struct Client *
find_id(const char *name)
{
        struct Client *target_p;
        dlink_node *ptr;
        unsigned int hashv;

        if(EmptyString(name))
                return NULL;

        hashv = hash_id(name);

        DLINK_FOREACH(ptr, idTable[hashv].head)
        {
                target_p = ptr->data;

                if(strcmp(name, target_p->id) == 0)
                        return target_p;
        }

        return NULL;
}

/* hash_find_masked_server()
 * 
 * Whats happening in this next loop ? Well, it takes a name like
 * foo.bar.edu and proceeds to earch for *.edu and then *.bar.edu.
 * This is for checking full server names against masks although
 * it isnt often done this way in lieu of using matches().
 *
 * Rewrote to do *.bar.edu first, which is the most likely case,
 * also made const correct
 * --Bleep
 */
static struct Client *
hash_find_masked_server(struct Client *source_p, const char *name)
{
        char buf[HOSTLEN + 1];
        char *p = buf;
        char *s;
        struct Client *server;

        if('*' == *name || '.' == *name)
                return NULL;

        /* copy it across to give us a buffer to work on */
        strlcpy(buf, name, sizeof(buf));

        while ((s = strchr(p, '.')) != 0)
        {
                *--s = '*';
                /*
                 * Dont need to check IsServer() here since nicknames cant
                 * have *'s in them anyway.
                 */
                if((server = find_server(source_p, s)))
                        return server;
                p = s + 2;
        }

        return NULL;
}

/* find_any_client()
 *
 * finds a client/server/masked server entry from the hash
 */
struct Client *
find_any_client(const char *name)
{
        struct Client *target_p;
        dlink_node *ptr;
        unsigned int hashv;

        s_assert(name != NULL);
        if(EmptyString(name))
                return NULL;

        /* hunting for an id, not a nick */
        if(IsDigit(*name))
                return (find_id(name));

        hashv = hash_nick(name);

        DLINK_FOREACH(ptr, clientTable[hashv].head)
        {
                target_p = ptr->data;

                if(irccmp(name, target_p->name) == 0)
                        return target_p;
        }

        /* wasnt found, look for a masked server */
        return hash_find_masked_server(NULL, name);
}

/* find_client()
 *
 * finds a client/server entry from the client hash table
 */
struct Client *
find_client(const char *name)
{
        struct Client *target_p;
        dlink_node *ptr;
        unsigned int hashv;

        s_assert(name != NULL);
        if(EmptyString(name))
                return NULL;

        /* hunting for an id, not a nick */
        if(IsDigit(*name))
                return (find_id(name));

        hashv = hash_nick(name);

        DLINK_FOREACH(ptr, clientTable[hashv].head)
        {
                target_p = ptr->data;

                if(irccmp(name, target_p->name) == 0)
                        return target_p;
        }

        return NULL;
}

/* find_named_client()
 *
 * finds a client/server entry from the client hash table
 */
struct Client *
find_named_client(const char *name)
{
        struct Client *target_p;
        dlink_node *ptr;
        unsigned int hashv;

        s_assert(name != NULL);
        if(EmptyString(name))
                return NULL;

        hashv = hash_nick(name);

        DLINK_FOREACH(ptr, clientTable[hashv].head)
        {
                target_p = ptr->data;

                if(irccmp(name, target_p->name) == 0)
                        return target_p;
        }

        return NULL;
}

/* find_server()
 *
 * finds a server from the client hash table
 */
struct Client *
find_server(struct Client *source_p, const char *name)
{
        struct Client *target_p;
        dlink_node *ptr;
        unsigned int hashv;
  
        if(EmptyString(name))
                return NULL;

        if((source_p == NULL || !MyClient(source_p)) && 
           IsDigit(*name) && strlen(name) == 3)
        {
                target_p = find_id(name);
                return(target_p);
        }

        hashv = hash_nick(name);

        DLINK_FOREACH(ptr, clientTable[hashv].head)
        {
                target_p = ptr->data;

                if((IsServer(target_p) || IsMe(target_p)) &&
                   irccmp(name, target_p->name) == 0)
                                return target_p;
        }

        /* wasnt found, look for a masked server */
        return hash_find_masked_server(source_p, name);
}

/* find_hostname()
 *
 * finds a hostname dlink list from the hostname hash table.
 * we return the full dlink list, because you can have multiple
 * entries with the same hostname
 */
dlink_node *
find_hostname(const char *hostname)
{
        unsigned int hashv;

        if(EmptyString(hostname))
                return NULL;

        hashv = hash_hostname(hostname);

        return hostTable[hashv].head;
}

/* find_channel()
 *
 * finds a channel from the channel hash table
 */
struct Channel *
find_channel(const char *name)
{
        struct Channel *chptr;
        dlink_node *ptr;
        unsigned int hashv;

        s_assert(name != NULL);
        if(EmptyString(name))
                return NULL;

        hashv = hash_channel(name);

        DLINK_FOREACH(ptr, channelTable[hashv].head)
        {
                chptr = ptr->data;

                if(irccmp(name, chptr->chname) == 0)
                        return chptr;
        }

        return NULL;
}

/*
 * get_or_create_channel
 * inputs       - client pointer
 *              - channel name
 *              - pointer to int flag whether channel was newly created or not
 * output       - returns channel block or NULL if illegal name
 *              - also modifies *isnew
 *
 *  Get Channel block for chname (and allocate a new channel
 *  block, if it didn't exist before).
 */
struct Channel *
get_or_create_channel(struct Client *client_p, const char *chname, int *isnew)
{
        struct Channel *chptr;
        dlink_node *ptr;
        unsigned int hashv;
        int len;
        const char *s = chname;

        if(EmptyString(s))
                return NULL;

        len = strlen(s);
        if(len > CHANNELLEN)
        {
                char *t;
                if(IsServer(client_p))
                {
                        sendto_realops_snomask(SNO_DEBUG, L_ALL,
                                             "*** Long channel name from %s (%d > %d): %s",
                                             client_p->name, len, CHANNELLEN, s);
                }
                len = CHANNELLEN;
                t = LOCAL_COPY(s);
                *(t + CHANNELLEN) = '\0';
                s = t;
        }

        hashv = hash_channel(s);

        DLINK_FOREACH(ptr, channelTable[hashv].head)
        {
                chptr = ptr->data;

                if(irccmp(s, chptr->chname) == 0)
                {
                        if(isnew != NULL)
                                *isnew = 0;
                        return chptr;
                }
        }

        if(isnew != NULL)
                *isnew = 1;

        chptr = allocate_channel(s);

        dlinkAdd(chptr, &chptr->node, &global_channel_list);

        chptr->channelts = CurrentTime; /* doesn't hurt to set it here */

        dlinkAddAlloc(chptr, &channelTable[hashv]);

        return chptr;
}

/* hash_find_resv()
 *
 * hunts for a resv entry in the resv hash table
 */
struct ConfItem *
hash_find_resv(const char *name)
{
        struct ConfItem *aconf;
        dlink_node *ptr;
        unsigned int hashv;

        s_assert(name != NULL);
        if(EmptyString(name))
                return NULL;

        hashv = hash_resv(name);

        DLINK_FOREACH(ptr, resvTable[hashv].head)
        {
                aconf = ptr->data;

                if(!irccmp(name, aconf->name))
                {
                        aconf->port++;
                        return aconf;
                }
        }

        return NULL;
}

struct cachefile *
hash_find_help(const char *name, int flags)
{
        struct cachefile *hptr;
        dlink_node *ptr;
        unsigned int hashv;

        if(EmptyString(name))
                return NULL;

        hashv = hash_help(name);

        DLINK_FOREACH(ptr, helpTable[hashv].head)
        {
                hptr = ptr->data;

                if((irccmp(name, hptr->name) == 0) &&
                   (hptr->flags & flags))
                        return hptr;
        }

        return NULL;
}

void
clear_resv_hash(void)
{
        struct ConfItem *aconf;
        dlink_node *ptr;
        dlink_node *next_ptr;
        int i;

        HASH_WALK_SAFE(i, R_MAX, ptr, next_ptr, resvTable)
        {
                aconf = ptr->data;

                /* skip temp resvs */
                if(aconf->hold)
                        continue;

                free_conf(ptr->data);
                dlinkDestroy(ptr, &resvTable[i]);
        }
        HASH_WALK_END
}

struct nd_entry *
hash_find_nd(const char *name)
{
        struct nd_entry *nd;
        dlink_node *ptr;
        unsigned int hashv;

        if(EmptyString(name))
                return NULL;

        hashv = hash_nick(name);

        DLINK_FOREACH(ptr, ndTable[hashv].head)
        {
                nd = ptr->data;

                if(!irccmp(name, nd->name))
                        return nd;
        }

        return NULL;
}

static void
output_hash(struct Client *source_p, const char *name, int length, int *counts, int deepest)
{
        unsigned long total = 0;
        int i;

        sendto_one_numeric(source_p, RPL_STATSDEBUG,
                        "B :%s Hash Statistics", name);

        sendto_one_numeric(source_p, RPL_STATSDEBUG,
                        "B :Size: %d Empty: %d (%.3f%%)",
                        length, counts[0], 
                        (float) ((counts[0]*100) / (float) length));

        for(i = 1; i < 11; i++)
        {
                total += (counts[i] * i);
        }

        /* dont want to divide by 0! --fl */
        if(counts[0] != length)
                sendto_one_numeric(source_p, RPL_STATSDEBUG,
                                "B :Average depth: %.3f/%.3f Highest depth: %d",
                                (float) (total / (length - counts[0])),
                                (float) (total / length), deepest);

        for(i = 0; i < 11; i++)
        {
                sendto_one_numeric(source_p, RPL_STATSDEBUG,
                                "B :Nodes with %d entries: %d",
                                i, counts[i]);
        }
}
        

static void
count_hash(struct Client *source_p, dlink_list *table, int length, const char *name)
{
        int counts[11];
        int deepest = 0;
        int i;

        memset(counts, 0, sizeof(counts));
        
        for(i = 0; i < length; i++)
        {
                if(dlink_list_length(&table[i]) >= 10)
                        counts[10]++;
                else
                        counts[dlink_list_length(&table[i])]++;

                if(dlink_list_length(&table[i]) > deepest)
                        deepest = dlink_list_length(&table[i]);
        }

        output_hash(source_p, name, length, counts, deepest);
}

void
hash_stats(struct Client *source_p)
{
        count_hash(source_p, channelTable, CH_MAX, "Channel");
        sendto_one_numeric(source_p, RPL_STATSDEBUG, "B :--");
        count_hash(source_p, clientTable, U_MAX, "Client");
        sendto_one_numeric(source_p, RPL_STATSDEBUG, "B :--");
        count_hash(source_p, idTable, U_MAX, "ID");
        sendto_one_numeric(source_p, RPL_STATSDEBUG, "B :--");
        count_hash(source_p, hostTable, HOST_MAX, "Hostname");
}