trunk/src/hash.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2015 ircd-hybrid 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
 */

/*! \file hash.c
 * \brief Hash table management.
 * \version $Id$
 */

#include "stdinc.h"
#include "list.h"
#include "conf.h"
#include "channel.h"
#include "channel_mode.h"
#include "client.h"
#include "modules.h"
#include "hash.h"
#include "resv.h"
#include "rng_mt.h"
#include "userhost.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "send.h"
#include "memory.h"
#include "mempool.h"
#include "dbuf.h"
#include "user.h"


static mp_pool_t *userhost_pool;
static mp_pool_t *namehost_pool;

static unsigned int hashf_xor_key;

/* The actual hash tables, They MUST be of the same HASHSIZE, variable
 * size tables could be supported but the rehash routine should also
 * rebuild the transformation maps, I kept the tables of equal size
 * so that I can use one hash function.
 */
static struct Client *idTable[HASHSIZE];
static struct Client *clientTable[HASHSIZE];
static struct Channel *channelTable[HASHSIZE];
static struct UserHost *userhostTable[HASHSIZE];


/* init_hash()
 *
 * inputs       - NONE
 * output       - NONE
 * side effects - Initialize the maps used by hash
 *                functions and clear the tables
 */
void
hash_init(void)
{
  userhost_pool = mp_pool_new(sizeof(struct UserHost), MP_CHUNK_SIZE_USERHOST);
  namehost_pool = mp_pool_new(sizeof(struct NameHost), MP_CHUNK_SIZE_NAMEHOST);

  hashf_xor_key = genrand_int32() % 256;  /* better than nothing --adx */
}

/*
 * New hash function based on the Fowler/Noll/Vo (FNV) algorithm from
 * http://www.isthe.com/chongo/tech/comp/fnv/
 *
 * Here, we use the FNV-1 method, which gives slightly better results
 * than FNV-1a.   -Michael
 */
unsigned int
strhash(const char *name)
{
  const unsigned char *p = (const unsigned char *)name;
  unsigned int hval = FNV1_32_INIT;

  if (EmptyString(p))
    return 0;

  for (; *p; ++p)
  {
    hval += (hval << 1) + (hval <<  4) + (hval << 7) +
            (hval << 8) + (hval << 24);
    hval ^= (ToLower(*p) ^ hashf_xor_key);
  }

  return (hval >> FNV1_32_BITS) ^ (hval & ((1 << FNV1_32_BITS) - 1));
}

/************************** Externally visible functions ********************/

/* Optimization note: in these functions I supposed that the CSE optimization
 * (Common Subexpression Elimination) does its work decently, this means that
 * I avoided introducing new variables to do the work myself and I did let
 * the optimizer play with more free registers, actual tests proved this
 * solution to be faster than doing things like tmp2=tmp->hnext... and then
 * use tmp2 myself which would have given less freedom to the optimizer.
 */

/* hash_add_client()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Adds a client's name in the proper hash linked
 *                list, can't fail, client_p must have a non-null
 *                name or expect a coredump, the name is infact
 *                taken from client_p->name
 */
void
hash_add_client(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->name);

  client_p->hnext = clientTable[hashv];
  clientTable[hashv] = client_p;
}

/* hash_add_channel()
 *
 * inputs       - pointer to channel
 * output       - NONE
 * side effects - Adds a channel's name in the proper hash linked
 *                list, can't fail. chptr must have a non-null name
 *                or expect a coredump. As before the name is taken
 *                from chptr->name, we do hash its entire lenght
 *                since this proved to be statistically faster
 */
void
hash_add_channel(struct Channel *chptr)
{
  const unsigned int hashv = strhash(chptr->name);

  chptr->hnextch = channelTable[hashv];
  channelTable[hashv] = chptr;
}

void
hash_add_userhost(struct UserHost *userhost)
{
  const unsigned int hashv = strhash(userhost->host);

  userhost->next = userhostTable[hashv];
  userhostTable[hashv] = userhost;
}

void
hash_add_id(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->id);

  client_p->idhnext = idTable[hashv];
  idTable[hashv] = client_p;
}

/* hash_del_id()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes an ID from the hash linked list
 */
void
hash_del_id(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->id);
  struct Client *tmp = idTable[hashv];

  if (tmp)
  {
    if (tmp == client_p)
    {
      idTable[hashv] = client_p->idhnext;
      client_p->idhnext = client_p;
    }
    else
    {
      while (tmp->idhnext != client_p)
        if ((tmp = tmp->idhnext) == NULL)
          return;

      tmp->idhnext = tmp->idhnext->idhnext;
      client_p->idhnext = client_p;
    }
  }
}

/* hash_del_client()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes a Client's name from the hash linked list
 */
void
hash_del_client(struct Client *client_p)
{
  const unsigned int hashv = strhash(client_p->name);
  struct Client *tmp = clientTable[hashv];

  if (tmp)
  {
    if (tmp == client_p)
    {
      clientTable[hashv] = client_p->hnext;
      client_p->hnext = client_p;
    }
    else
    {
      while (tmp->hnext != client_p)
        if ((tmp = tmp->hnext) == NULL)
          return;

      tmp->hnext = tmp->hnext->hnext;
      client_p->hnext = client_p;
    }
  }
}

/* hash_del_userhost()
 *
 * inputs       - pointer to userhost
 * output       - NONE
 * side effects - Removes a userhost from the hash linked list
 */
void
hash_del_userhost(struct UserHost *userhost)
{
  const unsigned int hashv = strhash(userhost->host);
  struct UserHost *tmp = userhostTable[hashv];

  if (tmp)
  {
    if (tmp == userhost)
    {
      userhostTable[hashv] = userhost->next;
      userhost->next = userhost;
    }
    else
    {
      while (tmp->next != userhost)
        if ((tmp = tmp->next) == NULL)
          return;

      tmp->next = tmp->next->next;
      userhost->next = userhost;
    }
  }
}

/* hash_del_channel()
 *
 * inputs       - pointer to client
 * output       - NONE
 * side effects - Removes the channel's name from the corresponding
 *                hash linked list
 */
void
hash_del_channel(struct Channel *chptr)
{
  const unsigned int hashv = strhash(chptr->name);
  struct Channel *tmp = channelTable[hashv];

  if (tmp)
  {
    if (tmp == chptr)
    {
      channelTable[hashv] = chptr->hnextch;
      chptr->hnextch = chptr;
    }
    else
    {
      while (tmp->hnextch != chptr)
        if ((tmp = tmp->hnextch) == NULL)
          return;

      tmp->hnextch = tmp->hnextch->hnextch;
      chptr->hnextch = chptr;
    }
  }
}

/* hash_find_client()
 *
 * inputs       - pointer to name
 * output       - NONE
 * side effects - New semantics: finds a client whose name is 'name'
 *                if can't find one returns NULL. If it finds one moves
 *                it to the top of the list and returns it.
 */
struct Client *
hash_find_client(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p;

  if ((client_p = clientTable[hashv]))
  {
    if (irccmp(name, client_p->name))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->hnext))
      {
        if (!irccmp(name, client_p->name))
        {
          prev->hnext = client_p->hnext;
          client_p->hnext = clientTable[hashv];
          clientTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

struct Client *
hash_find_id(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p;

  if ((client_p = idTable[hashv]))
  {
    if (strcmp(name, client_p->id))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->idhnext))
      {
        if (!strcmp(name, client_p->id))
        {
          prev->idhnext = client_p->idhnext;
          client_p->idhnext = idTable[hashv];
          idTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

struct Client *
hash_find_server(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Client *client_p = NULL;

  if (IsDigit(*name) && strlen(name) == IRC_MAXSID)
    return hash_find_id(name);

  if ((client_p = clientTable[hashv]))
  {
    if ((!IsServer(client_p) && !IsMe(client_p)) ||
        irccmp(name, client_p->name))
    {
      struct Client *prev;

      while (prev = client_p, (client_p = client_p->hnext))
      {
        if ((IsServer(client_p) || IsMe(client_p)) &&
            !irccmp(name, client_p->name))
        {
          prev->hnext = client_p->hnext;
          client_p->hnext = clientTable[hashv];
          clientTable[hashv] = client_p;
          break;
        }
      }
    }
  }

  return client_p;
}

/* hash_find_channel()
 *
 * inputs       - pointer to name
 * output       - NONE
 * side effects - New semantics: finds a channel whose name is 'name',
 *                if can't find one returns NULL, if can find it moves
 *                it to the top of the list and returns it.
 */
struct Channel *
hash_find_channel(const char *name)
{
  const unsigned int hashv = strhash(name);
  struct Channel *chptr = NULL;

  if ((chptr = channelTable[hashv]))
  {
    if (irccmp(name, chptr->name))
    {
      struct Channel *prev;

      while (prev = chptr, (chptr = chptr->hnextch))
      {
        if (!irccmp(name, chptr->name))
        {
          prev->hnextch = chptr->hnextch;
          chptr->hnextch = channelTable[hashv];
          channelTable[hashv] = chptr;
          break;
        }
      }
    }
  }

  return chptr;
}

/* hash_get_bucket(int type, unsigned int hashv)
 *
 * inputs       - hash value (must be between 0 and HASHSIZE - 1)
 * output       - NONE
 * returns      - pointer to first channel in channelTable[hashv]
 *                if that exists;
 *                NULL if there is no channel in that place;
 *                NULL if hashv is an invalid number.
 * side effects - NONE
 */
void *
hash_get_bucket(int type, unsigned int hashv)
{
  assert(hashv < HASHSIZE);

  if (hashv >= HASHSIZE)
      return NULL;

  switch (type)
  {
    case HASH_TYPE_ID:
      return idTable[hashv];
      break;
    case HASH_TYPE_CHANNEL:
      return channelTable[hashv];
      break;
    case HASH_TYPE_CLIENT:
      return clientTable[hashv];
      break;
    case HASH_TYPE_USERHOST:
      return userhostTable[hashv];
      break;
    default:
      assert(0);
  }

  return NULL;
}

struct UserHost *
hash_find_userhost(const char *host)
{
  const unsigned int hashv = strhash(host);
  struct UserHost *userhost;

  if ((userhost = userhostTable[hashv]))
  {
    if (irccmp(host, userhost->host))
    {
      struct UserHost *prev;

      while (prev = userhost, (userhost = userhost->next))
      {
        if (!irccmp(host, userhost->host))
        {
          prev->next = userhost->next;
          userhost->next = userhostTable[hashv];
          userhostTable[hashv] = userhost;
          break;
        }
      }
    }
  }

  return userhost;
}

/* count_user_host()
 *
 * inputs       - user name
 *              - hostname
 *              - int flag 1 if global, 0 if local
 *              - pointer to where global count should go
 *              - pointer to where local count should go
 *              - pointer to where identd count should go (local clients only)
 * output       - none
 * side effects -
 */
void
count_user_host(const char *user, const char *host, unsigned int *global_p,
                unsigned int *local_p, unsigned int *icount_p)
{
  dlink_node *node = NULL;
  struct UserHost *found_userhost;

  if ((found_userhost = hash_find_userhost(host)) == NULL)
    return;

  DLINK_FOREACH(node, found_userhost->list.head)
  {
    struct NameHost *nameh = node->data;

    if (!irccmp(user, nameh->name))
    {
      if (global_p)
        *global_p = nameh->gcount;
      if (local_p)
        *local_p  = nameh->lcount;
      if (icount_p)
        *icount_p = nameh->icount;

      return;
    }
  }
}

/* find_or_add_userhost()
 *
 * inputs       - host name
 * output       - none
 * side effects - find UserHost * for given host name
 */
static struct UserHost *
find_or_add_userhost(const char *host)
{
  struct UserHost *userhost = NULL;

  if ((userhost = hash_find_userhost(host)))
    return userhost;

  userhost = mp_pool_get(userhost_pool);

  strlcpy(userhost->host, host, sizeof(userhost->host));
  hash_add_userhost(userhost);

  return userhost;
}

/* add_user_host()
 *
 * inputs       - user name
 *              - hostname
 *              - int flag 1 if global, 0 if local
 * output       - none
 * side effects - add given user@host to hash tables
 */
void
add_user_host(const char *user, const char *host, int global)
{
  dlink_node *node = NULL;
  struct UserHost *found_userhost;
  struct NameHost *nameh;
  unsigned int hasident = 1;

  if (*user == '~')
  {
    hasident = 0;
    ++user;
  }

  if ((found_userhost = find_or_add_userhost(host)) == NULL)
    return;

  DLINK_FOREACH(node, found_userhost->list.head)
  {
    nameh = node->data;

    if (!irccmp(user, nameh->name))
    {
      nameh->gcount++;

      if (!global)
      {
        if (hasident)
          nameh->icount++;
        nameh->lcount++;
      }

      return;
    }
  }

  nameh = mp_pool_get(namehost_pool);
  nameh->gcount = 1;
  strlcpy(nameh->name, user, sizeof(nameh->name));

  if (!global)
  {
    if (hasident)
      nameh->icount = 1;

    nameh->lcount = 1;
  }

  dlinkAdd(nameh, &nameh->node, &found_userhost->list);
}

/* delete_user_host()
 *
 * inputs       - user name
 *              - hostname
 *              - int flag 1 if global, 0 if local
 * output       - none
 * side effects - delete given user@host to hash tables
 */
void
delete_user_host(const char *user, const char *host, int global)
{
  dlink_node *node = NULL;
  struct UserHost *found_userhost = NULL;
  unsigned int hasident = 1;

  if (*user == '~')
  {
    hasident = 0;
    ++user;
  }

  if ((found_userhost = hash_find_userhost(host)) == NULL)
    return;

  DLINK_FOREACH(node, found_userhost->list.head)
  {
    struct NameHost *nameh = node->data;

    if (!irccmp(user, nameh->name))
    {
      if (nameh->gcount > 0)
        nameh->gcount--;

      if (!global)
      {
        if (nameh->lcount > 0)
          nameh->lcount--;

        if (hasident && nameh->icount > 0)
          nameh->icount--;
      }

      if (nameh->gcount == 0 && nameh->lcount == 0)
      {
        dlinkDelete(&nameh->node, &found_userhost->list);
        mp_pool_release(nameh);
      }

      if (dlink_list_length(&found_userhost->list) == 0)
      {
        hash_del_userhost(found_userhost);
        mp_pool_release(found_userhost);
      }

      return;
    }
  }
}

/*
 * Safe list code.
 *
 * The idea is really quite simple. As the link lists pointed to in
 * each "bucket" of the channel hash table are traversed atomically
 * there is no locking needed. Overall, yes, inconsistent reported
 * state can still happen, but normally this isn't a big deal.
 * I don't like sticking the code into hash.c but oh well. Moreover,
 * if a hash isn't used in future, oops.
 *
 * - Dianora
 */

/* exceeding_sendq()
 *
 * inputs       - pointer to client to check
 * output       - 1 if client is in danger of blowing its sendq
 *                0 if it is not.
 * side effects -
 *
 * Sendq limit is fairly conservative at 1/2 (In original anyway)
 */
static int
exceeding_sendq(const struct Client *to)
{
  if (dbuf_length(&to->connection->buf_sendq) > (get_sendq(&to->connection->confs) / 2))
    return 1;
  else
    return 0;
}

void
free_list_task(struct Client *source_p)
{
  struct ListTask *const lt = source_p->connection->list_task;
  dlink_node *node = NULL, *node_next = NULL;

  if ((node = dlinkFindDelete(&listing_client_list, source_p)))
    free_dlink_node(node);

  DLINK_FOREACH_SAFE(node, node_next, lt->show_mask.head)
  {
    MyFree(node->data);
    free_dlink_node(node);
  }

  DLINK_FOREACH_SAFE(node, node_next, lt->hide_mask.head)
  {
    MyFree(node->data);
    free_dlink_node(node);
  }

  MyFree(lt);
  source_p->connection->list_task = NULL;
}

/* list_allow_channel()
 *
 * inputs       - channel name
 *              - pointer to a list task
 * output       - 1 if the channel is to be displayed
 *                0 otherwise
 * side effects -
 */
static int
list_allow_channel(const char *name, const struct ListTask *lt)
{
  const dlink_node *node = NULL;

  DLINK_FOREACH(node, lt->show_mask.head)
    if (match(node->data, name) != 0)
      return 0;

  DLINK_FOREACH(node, lt->hide_mask.head)
    if (match(node->data, name) == 0)
      return 0;

  return 1;
}

/* list_one_channel()
 *
 * inputs       - client pointer to return result to
 *              - pointer to channel to list
 *              - pointer to ListTask structure
 * output       - none
 * side effects -
 */
static void
list_one_channel(struct Client *source_p, struct Channel *chptr)
{
  const struct ListTask *const lt = source_p->connection->list_task;
  char listbuf[MODEBUFLEN] = "";
  char modebuf[MODEBUFLEN] = "";
  char parabuf[MODEBUFLEN] = "";

  if (SecretChannel(chptr) &&
      !(HasUMode(source_p, UMODE_ADMIN) || IsMember(source_p, chptr)))
    return;

  if (dlink_list_length(&chptr->members) < lt->users_min ||
      dlink_list_length(&chptr->members) > lt->users_max ||
      (chptr->creationtime != 0 &&
       ((unsigned int)chptr->creationtime < lt->created_min ||
        (unsigned int)chptr->creationtime > lt->created_max)) ||
      (unsigned int)chptr->topic_time < lt->topicts_min ||
      (chptr->topic_time ? (unsigned int)chptr->topic_time : UINT_MAX) >
      lt->topicts_max)
    return;

  if (lt->topic[0] && match(lt->topic, chptr->topic))
    return;

  if (!list_allow_channel(chptr->name, lt))
    return;

  channel_modes(chptr, source_p, modebuf, parabuf);

  if (chptr->topic[0])
    snprintf(listbuf, sizeof(listbuf), "[%s] ", modebuf);
  else
    snprintf(listbuf, sizeof(listbuf), "[%s]",  modebuf);

  sendto_one_numeric(source_p, &me, RPL_LIST, chptr->name,
                     dlink_list_length(&chptr->members),
                     listbuf, chptr->topic);
}

/* safe_list_channels()
 *
 * inputs       - pointer to client requesting list
 * output       - 0/1
 * side effects - safely list all channels to source_p
 *
 * Walk the channel buckets, ensure all pointers in a bucket are
 * traversed before blocking on a sendq. This means, no locking is needed.
 *
 * - Dianora
 */
void
safe_list_channels(struct Client *source_p, int only_unmasked_channels)
{
  struct ListTask *const lt = source_p->connection->list_task;
  struct Channel *chptr = NULL;

  if (!only_unmasked_channels)
  {
    for (unsigned int i = lt->hash_index; i < HASHSIZE; ++i)
    {
      if (exceeding_sendq(source_p))
      {
        lt->hash_index = i;
        return;  /* Still more to do */
      }

      for (chptr = channelTable[i]; chptr; chptr = chptr->hnextch)
        list_one_channel(source_p, chptr);
    }
  }
  else
  {
    dlink_node *node = NULL;

    DLINK_FOREACH(node, lt->show_mask.head)
      if ((chptr = hash_find_channel(node->data)))
        list_one_channel(source_p, chptr);
  }

  free_list_task(source_p);
  sendto_one_numeric(source_p, &me, RPL_LISTEND);
}
Revision:	5545
Committed:	Thu Feb 12 14:13:34 2015 UTC (10 years, 6 months ago) by michael
Content type:	text/x-csrc
File size:	19972 byte(s)
Log Message:	- Fixed style in several places
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2015 ircd-hybrid development team
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	* USA
20	*/
21
22	/*! \file hash.c
23	* \brief Hash table management.
24	* \version $Id$
25	*/
26
27	#include "stdinc.h"
28	#include "list.h"
29	#include "conf.h"
30	#include "channel.h"
31	#include "channel_mode.h"
32	#include "client.h"
33	#include "modules.h"
34	#include "hash.h"
35	#include "resv.h"
36	#include "rng_mt.h"
37	#include "userhost.h"
38	#include "irc_string.h"
39	#include "ircd.h"
40	#include "numeric.h"
41	#include "send.h"
42	#include "memory.h"
43	#include "mempool.h"
44	#include "dbuf.h"
45	#include "user.h"
46
47
48	static mp_pool_t *userhost_pool;
49	static mp_pool_t *namehost_pool;
50
51	static unsigned int hashf_xor_key;
52
53	/* The actual hash tables, They MUST be of the same HASHSIZE, variable
54	* size tables could be supported but the rehash routine should also
55	* rebuild the transformation maps, I kept the tables of equal size
56	* so that I can use one hash function.
57	*/
58	static struct Client *idTable[HASHSIZE];
59	static struct Client *clientTable[HASHSIZE];
60	static struct Channel *channelTable[HASHSIZE];
61	static struct UserHost *userhostTable[HASHSIZE];
62
63
64	/* init_hash()
65	*
66	* inputs - NONE
67	* output - NONE
68	* side effects - Initialize the maps used by hash
69	* functions and clear the tables
70	*/
71	void
72	hash_init(void)
73	{
74	userhost_pool = mp_pool_new(sizeof(struct UserHost), MP_CHUNK_SIZE_USERHOST);
75	namehost_pool = mp_pool_new(sizeof(struct NameHost), MP_CHUNK_SIZE_NAMEHOST);
76
77	hashf_xor_key = genrand_int32() % 256; /* better than nothing --adx */
78	}
79
80	/*
81	* New hash function based on the Fowler/Noll/Vo (FNV) algorithm from
82	* http://www.isthe.com/chongo/tech/comp/fnv/
83	*
84	* Here, we use the FNV-1 method, which gives slightly better results
85	* than FNV-1a. -Michael
86	*/
87	unsigned int
88	strhash(const char *name)
89	{
90	const unsigned char p = (const unsigned char )name;
91	unsigned int hval = FNV1_32_INIT;
92
93	if (EmptyString(p))
94	return 0;
95
96	for (; *p; ++p)
97	{
98	hval += (hval << 1) + (hval << 4) + (hval << 7) +
99	(hval << 8) + (hval << 24);
100	hval ^= (ToLower(*p) ^ hashf_xor_key);
101	}
102
103	return (hval >> FNV1_32_BITS) ^ (hval & ((1 << FNV1_32_BITS) - 1));
104	}
105
106	/************************ Externally visible functions ******************/
107
108	/* Optimization note: in these functions I supposed that the CSE optimization
109	* (Common Subexpression Elimination) does its work decently, this means that
110	* I avoided introducing new variables to do the work myself and I did let
111	* the optimizer play with more free registers, actual tests proved this
112	* solution to be faster than doing things like tmp2=tmp->hnext... and then
113	* use tmp2 myself which would have given less freedom to the optimizer.
114	*/
115
116	/* hash_add_client()
117	*
118	* inputs - pointer to client
119	* output - NONE
120	* side effects - Adds a client's name in the proper hash linked
121	* list, can't fail, client_p must have a non-null
122	* name or expect a coredump, the name is infact
123	* taken from client_p->name
124	*/
125	void
126	hash_add_client(struct Client *client_p)
127	{
128	const unsigned int hashv = strhash(client_p->name);
129
130	client_p->hnext = clientTable[hashv];
131	clientTable[hashv] = client_p;
132	}
133
134	/* hash_add_channel()
135	*
136	* inputs - pointer to channel
137	* output - NONE
138	* side effects - Adds a channel's name in the proper hash linked
139	* list, can't fail. chptr must have a non-null name
140	* or expect a coredump. As before the name is taken
141	* from chptr->name, we do hash its entire lenght
142	* since this proved to be statistically faster
143	*/
144	void
145	hash_add_channel(struct Channel *chptr)
146	{
147	const unsigned int hashv = strhash(chptr->name);
148
149	chptr->hnextch = channelTable[hashv];
150	channelTable[hashv] = chptr;
151	}
152
153	void
154	hash_add_userhost(struct UserHost *userhost)
155	{
156	const unsigned int hashv = strhash(userhost->host);
157
158	userhost->next = userhostTable[hashv];
159	userhostTable[hashv] = userhost;
160	}
161
162	void
163	hash_add_id(struct Client *client_p)
164	{
165	const unsigned int hashv = strhash(client_p->id);
166
167	client_p->idhnext = idTable[hashv];
168	idTable[hashv] = client_p;
169	}
170
171	/* hash_del_id()
172	*
173	* inputs - pointer to client
174	* output - NONE
175	* side effects - Removes an ID from the hash linked list
176	*/
177	void
178	hash_del_id(struct Client *client_p)
179	{
180	const unsigned int hashv = strhash(client_p->id);
181	struct Client *tmp = idTable[hashv];
182
183	if (tmp)
184	{
185	if (tmp == client_p)
186	{
187	idTable[hashv] = client_p->idhnext;
188	client_p->idhnext = client_p;
189	}
190	else
191	{
192	while (tmp->idhnext != client_p)
193	if ((tmp = tmp->idhnext) == NULL)
194	return;
195
196	tmp->idhnext = tmp->idhnext->idhnext;
197	client_p->idhnext = client_p;
198	}
199	}
200	}
201
202	/* hash_del_client()
203	*
204	* inputs - pointer to client
205	* output - NONE
206	* side effects - Removes a Client's name from the hash linked list
207	*/
208	void
209	hash_del_client(struct Client *client_p)
210	{
211	const unsigned int hashv = strhash(client_p->name);
212	struct Client *tmp = clientTable[hashv];
213
214	if (tmp)
215	{
216	if (tmp == client_p)
217	{
218	clientTable[hashv] = client_p->hnext;
219	client_p->hnext = client_p;
220	}
221	else
222	{
223	while (tmp->hnext != client_p)
224	if ((tmp = tmp->hnext) == NULL)
225	return;
226
227	tmp->hnext = tmp->hnext->hnext;
228	client_p->hnext = client_p;
229	}
230	}
231	}
232
233	/* hash_del_userhost()
234	*
235	* inputs - pointer to userhost
236	* output - NONE
237	* side effects - Removes a userhost from the hash linked list
238	*/
239	void
240	hash_del_userhost(struct UserHost *userhost)
241	{
242	const unsigned int hashv = strhash(userhost->host);
243	struct UserHost *tmp = userhostTable[hashv];
244
245	if (tmp)
246	{
247	if (tmp == userhost)
248	{
249	userhostTable[hashv] = userhost->next;
250	userhost->next = userhost;
251	}
252	else
253	{
254	while (tmp->next != userhost)
255	if ((tmp = tmp->next) == NULL)
256	return;
257
258	tmp->next = tmp->next->next;
259	userhost->next = userhost;
260	}
261	}
262	}
263
264	/* hash_del_channel()
265	*
266	* inputs - pointer to client
267	* output - NONE
268	* side effects - Removes the channel's name from the corresponding
269	* hash linked list
270	*/
271	void
272	hash_del_channel(struct Channel *chptr)
273	{
274	const unsigned int hashv = strhash(chptr->name);
275	struct Channel *tmp = channelTable[hashv];
276
277	if (tmp)
278	{
279	if (tmp == chptr)
280	{
281	channelTable[hashv] = chptr->hnextch;
282	chptr->hnextch = chptr;
283	}
284	else
285	{
286	while (tmp->hnextch != chptr)
287	if ((tmp = tmp->hnextch) == NULL)
288	return;
289
290	tmp->hnextch = tmp->hnextch->hnextch;
291	chptr->hnextch = chptr;
292	}
293	}
294	}
295
296	/* hash_find_client()
297	*
298	* inputs - pointer to name
299	* output - NONE
300	* side effects - New semantics: finds a client whose name is 'name'
301	* if can't find one returns NULL. If it finds one moves
302	* it to the top of the list and returns it.
303	*/
304	struct Client *
305	hash_find_client(const char *name)
306	{
307	const unsigned int hashv = strhash(name);
308	struct Client *client_p;
309
310	if ((client_p = clientTable[hashv]))
311	{
312	if (irccmp(name, client_p->name))
313	{
314	struct Client *prev;
315
316	while (prev = client_p, (client_p = client_p->hnext))
317	{
318	if (!irccmp(name, client_p->name))
319	{
320	prev->hnext = client_p->hnext;
321	client_p->hnext = clientTable[hashv];
322	clientTable[hashv] = client_p;
323	break;
324	}
325	}
326	}
327	}
328
329	return client_p;
330	}
331
332	struct Client *
333	hash_find_id(const char *name)
334	{
335	const unsigned int hashv = strhash(name);
336	struct Client *client_p;
337
338	if ((client_p = idTable[hashv]))
339	{
340	if (strcmp(name, client_p->id))
341	{
342	struct Client *prev;
343
344	while (prev = client_p, (client_p = client_p->idhnext))
345	{
346	if (!strcmp(name, client_p->id))
347	{
348	prev->idhnext = client_p->idhnext;
349	client_p->idhnext = idTable[hashv];
350	idTable[hashv] = client_p;
351	break;
352	}
353	}
354	}
355	}
356
357	return client_p;
358	}
359
360	struct Client *
361	hash_find_server(const char *name)
362	{
363	const unsigned int hashv = strhash(name);
364	struct Client *client_p = NULL;
365
366	if (IsDigit(*name) && strlen(name) == IRC_MAXSID)
367	return hash_find_id(name);
368
369	if ((client_p = clientTable[hashv]))
370	{
371	if ((!IsServer(client_p) && !IsMe(client_p)) \|\|
372	irccmp(name, client_p->name))
373	{
374	struct Client *prev;
375
376	while (prev = client_p, (client_p = client_p->hnext))
377	{
378	if ((IsServer(client_p) \|\| IsMe(client_p)) &&
379	!irccmp(name, client_p->name))
380	{
381	prev->hnext = client_p->hnext;
382	client_p->hnext = clientTable[hashv];
383	clientTable[hashv] = client_p;
384	break;
385	}
386	}
387	}
388	}
389
390	return client_p;
391	}
392
393	/* hash_find_channel()
394	*
395	* inputs - pointer to name
396	* output - NONE
397	* side effects - New semantics: finds a channel whose name is 'name',
398	* if can't find one returns NULL, if can find it moves
399	* it to the top of the list and returns it.
400	*/
401	struct Channel *
402	hash_find_channel(const char *name)
403	{
404	const unsigned int hashv = strhash(name);
405	struct Channel *chptr = NULL;
406
407	if ((chptr = channelTable[hashv]))
408	{
409	if (irccmp(name, chptr->name))
410	{
411	struct Channel *prev;
412
413	while (prev = chptr, (chptr = chptr->hnextch))
414	{
415	if (!irccmp(name, chptr->name))
416	{
417	prev->hnextch = chptr->hnextch;
418	chptr->hnextch = channelTable[hashv];
419	channelTable[hashv] = chptr;
420	break;
421	}
422	}
423	}
424	}
425
426	return chptr;
427	}
428
429	/* hash_get_bucket(int type, unsigned int hashv)
430	*
431	* inputs - hash value (must be between 0 and HASHSIZE - 1)
432	* output - NONE
433	* returns - pointer to first channel in channelTable[hashv]
434	* if that exists;
435	* NULL if there is no channel in that place;
436	* NULL if hashv is an invalid number.
437	* side effects - NONE
438	*/
439	void *
440	hash_get_bucket(int type, unsigned int hashv)
441	{
442	assert(hashv < HASHSIZE);
443
444	if (hashv >= HASHSIZE)
445	return NULL;
446
447	switch (type)
448	{
449	case HASH_TYPE_ID:
450	return idTable[hashv];
451	break;
452	case HASH_TYPE_CHANNEL:
453	return channelTable[hashv];
454	break;
455	case HASH_TYPE_CLIENT:
456	return clientTable[hashv];
457	break;
458	case HASH_TYPE_USERHOST:
459	return userhostTable[hashv];
460	break;
461	default:
462	assert(0);
463	}
464
465	return NULL;
466	}
467
468	struct UserHost *
469	hash_find_userhost(const char *host)
470	{
471	const unsigned int hashv = strhash(host);
472	struct UserHost *userhost;
473
474	if ((userhost = userhostTable[hashv]))
475	{
476	if (irccmp(host, userhost->host))
477	{
478	struct UserHost *prev;
479
480	while (prev = userhost, (userhost = userhost->next))
481	{
482	if (!irccmp(host, userhost->host))
483	{
484	prev->next = userhost->next;
485	userhost->next = userhostTable[hashv];
486	userhostTable[hashv] = userhost;
487	break;
488	}
489	}
490	}
491	}
492
493	return userhost;
494	}
495
496	/* count_user_host()
497	*
498	* inputs - user name
499	* - hostname
500	* - int flag 1 if global, 0 if local
501	* - pointer to where global count should go
502	* - pointer to where local count should go
503	* - pointer to where identd count should go (local clients only)
504	* output - none
505	* side effects -
506	*/
507	void
508	count_user_host(const char user, const char host, unsigned int *global_p,
509	unsigned int local_p, unsigned int icount_p)
510	{
511	dlink_node *node = NULL;
512	struct UserHost *found_userhost;
513
514	if ((found_userhost = hash_find_userhost(host)) == NULL)
515	return;
516
517	DLINK_FOREACH(node, found_userhost->list.head)
518	{
519	struct NameHost *nameh = node->data;
520
521	if (!irccmp(user, nameh->name))
522	{
523	if (global_p)
524	*global_p = nameh->gcount;
525	if (local_p)
526	*local_p = nameh->lcount;
527	if (icount_p)
528	*icount_p = nameh->icount;
529
530	return;
531	}
532	}
533	}
534
535	/* find_or_add_userhost()
536	*
537	* inputs - host name
538	* output - none
539	* side effects - find UserHost * for given host name
540	*/
541	static struct UserHost *
542	find_or_add_userhost(const char *host)
543	{
544	struct UserHost *userhost = NULL;
545
546	if ((userhost = hash_find_userhost(host)))
547	return userhost;
548
549	userhost = mp_pool_get(userhost_pool);
550
551	strlcpy(userhost->host, host, sizeof(userhost->host));
552	hash_add_userhost(userhost);
553
554	return userhost;
555	}
556
557	/* add_user_host()
558	*
559	* inputs - user name
560	* - hostname
561	* - int flag 1 if global, 0 if local
562	* output - none
563	* side effects - add given user@host to hash tables
564	*/
565	void
566	add_user_host(const char user, const char host, int global)
567	{
568	dlink_node *node = NULL;
569	struct UserHost *found_userhost;
570	struct NameHost *nameh;
571	unsigned int hasident = 1;
572
573	if (*user == '~')
574	{
575	hasident = 0;
576	++user;
577	}
578
579	if ((found_userhost = find_or_add_userhost(host)) == NULL)
580	return;
581
582	DLINK_FOREACH(node, found_userhost->list.head)
583	{
584	nameh = node->data;
585
586	if (!irccmp(user, nameh->name))
587	{
588	nameh->gcount++;
589
590	if (!global)
591	{
592	if (hasident)
593	nameh->icount++;
594	nameh->lcount++;
595	}
596
597	return;
598	}
599	}
600
601	nameh = mp_pool_get(namehost_pool);
602	nameh->gcount = 1;
603	strlcpy(nameh->name, user, sizeof(nameh->name));
604
605	if (!global)
606	{
607	if (hasident)
608	nameh->icount = 1;
609
610	nameh->lcount = 1;
611	}
612
613	dlinkAdd(nameh, &nameh->node, &found_userhost->list);
614	}
615
616	/* delete_user_host()
617	*
618	* inputs - user name
619	* - hostname
620	* - int flag 1 if global, 0 if local
621	* output - none
622	* side effects - delete given user@host to hash tables
623	*/
624	void
625	delete_user_host(const char user, const char host, int global)
626	{
627	dlink_node *node = NULL;
628	struct UserHost *found_userhost = NULL;
629	unsigned int hasident = 1;
630
631	if (*user == '~')
632	{
633	hasident = 0;
634	++user;
635	}
636
637	if ((found_userhost = hash_find_userhost(host)) == NULL)
638	return;
639
640	DLINK_FOREACH(node, found_userhost->list.head)
641	{
642	struct NameHost *nameh = node->data;
643
644	if (!irccmp(user, nameh->name))
645	{
646	if (nameh->gcount > 0)
647	nameh->gcount--;
648
649	if (!global)
650	{
651	if (nameh->lcount > 0)
652	nameh->lcount--;
653
654	if (hasident && nameh->icount > 0)
655	nameh->icount--;
656	}
657
658	if (nameh->gcount == 0 && nameh->lcount == 0)
659	{
660	dlinkDelete(&nameh->node, &found_userhost->list);
661	mp_pool_release(nameh);
662	}
663
664	if (dlink_list_length(&found_userhost->list) == 0)
665	{
666	hash_del_userhost(found_userhost);
667	mp_pool_release(found_userhost);
668	}
669
670	return;
671	}
672	}
673	}
674
675	/*
676	* Safe list code.
677	*
678	* The idea is really quite simple. As the link lists pointed to in
679	* each "bucket" of the channel hash table are traversed atomically
680	* there is no locking needed. Overall, yes, inconsistent reported
681	* state can still happen, but normally this isn't a big deal.
682	* I don't like sticking the code into hash.c but oh well. Moreover,
683	* if a hash isn't used in future, oops.
684	*
685	* - Dianora
686	*/
687
688	/* exceeding_sendq()
689	*
690	* inputs - pointer to client to check
691	* output - 1 if client is in danger of blowing its sendq
692	* 0 if it is not.
693	* side effects -
694	*
695	* Sendq limit is fairly conservative at 1/2 (In original anyway)
696	*/
697	static int
698	exceeding_sendq(const struct Client *to)
699	{
700	if (dbuf_length(&to->connection->buf_sendq) > (get_sendq(&to->connection->confs) / 2))
701	return 1;
702	else
703	return 0;
704	}
705
706	void
707	free_list_task(struct Client *source_p)
708	{
709	struct ListTask *const lt = source_p->connection->list_task;
710	dlink_node node = NULL, node_next = NULL;
711
712	if ((node = dlinkFindDelete(&listing_client_list, source_p)))
713	free_dlink_node(node);
714
715	DLINK_FOREACH_SAFE(node, node_next, lt->show_mask.head)
716	{
717	MyFree(node->data);
718	free_dlink_node(node);
719	}
720
721	DLINK_FOREACH_SAFE(node, node_next, lt->hide_mask.head)
722	{
723	MyFree(node->data);
724	free_dlink_node(node);
725	}
726
727	MyFree(lt);
728	source_p->connection->list_task = NULL;
729	}
730
731	/* list_allow_channel()
732	*
733	* inputs - channel name
734	* - pointer to a list task
735	* output - 1 if the channel is to be displayed
736	* 0 otherwise
737	* side effects -
738	*/
739	static int
740	list_allow_channel(const char name, const struct ListTask lt)
741	{
742	const dlink_node *node = NULL;
743
744	DLINK_FOREACH(node, lt->show_mask.head)
745	if (match(node->data, name) != 0)
746	return 0;
747
748	DLINK_FOREACH(node, lt->hide_mask.head)
749	if (match(node->data, name) == 0)
750	return 0;
751
752	return 1;
753	}
754
755	/* list_one_channel()
756	*
757	* inputs - client pointer to return result to
758	* - pointer to channel to list
759	* - pointer to ListTask structure
760	* output - none
761	* side effects -
762	*/
763	static void
764	list_one_channel(struct Client source_p, struct Channel chptr)
765	{
766	const struct ListTask *const lt = source_p->connection->list_task;
767	char listbuf[MODEBUFLEN] = "";
768	char modebuf[MODEBUFLEN] = "";
769	char parabuf[MODEBUFLEN] = "";
770
771	if (SecretChannel(chptr) &&
772	!(HasUMode(source_p, UMODE_ADMIN) \|\| IsMember(source_p, chptr)))
773	return;
774
775	if (dlink_list_length(&chptr->members) < lt->users_min \|\|
776	dlink_list_length(&chptr->members) > lt->users_max \|\|
777	(chptr->creationtime != 0 &&
778	((unsigned int)chptr->creationtime < lt->created_min \|\|
779	(unsigned int)chptr->creationtime > lt->created_max)) \|\|
780	(unsigned int)chptr->topic_time < lt->topicts_min \|\|
781	(chptr->topic_time ? (unsigned int)chptr->topic_time : UINT_MAX) >
782	lt->topicts_max)
783	return;
784
785	if (lt->topic[0] && match(lt->topic, chptr->topic))
786	return;
787
788	if (!list_allow_channel(chptr->name, lt))
789	return;
790
791	channel_modes(chptr, source_p, modebuf, parabuf);
792
793	if (chptr->topic[0])
794	snprintf(listbuf, sizeof(listbuf), "[%s] ", modebuf);
795	else
796	snprintf(listbuf, sizeof(listbuf), "[%s]", modebuf);
797
798	sendto_one_numeric(source_p, &me, RPL_LIST, chptr->name,
799	dlink_list_length(&chptr->members),
800	listbuf, chptr->topic);
801	}
802
803	/* safe_list_channels()
804	*
805	* inputs - pointer to client requesting list
806	* output - 0/1
807	* side effects - safely list all channels to source_p
808	*
809	* Walk the channel buckets, ensure all pointers in a bucket are
810	* traversed before blocking on a sendq. This means, no locking is needed.
811	*
812	* - Dianora
813	*/
814	void
815	safe_list_channels(struct Client *source_p, int only_unmasked_channels)
816	{
817	struct ListTask *const lt = source_p->connection->list_task;
818	struct Channel *chptr = NULL;
819
820	if (!only_unmasked_channels)
821	{
822	for (unsigned int i = lt->hash_index; i < HASHSIZE; ++i)
823	{
824	if (exceeding_sendq(source_p))
825	{
826	lt->hash_index = i;
827	return; /* Still more to do */
828	}
829
830	for (chptr = channelTable[i]; chptr; chptr = chptr->hnextch)
831	list_one_channel(source_p, chptr);
832	}
833	}
834	else
835	{
836	dlink_node *node = NULL;
837
838	DLINK_FOREACH(node, lt->show_mask.head)
839	if ((chptr = hash_find_channel(node->data)))
840	list_one_channel(source_p, chptr);
841	}
842
843	free_list_task(source_p);
844	sendto_one_numeric(source_p, &me, RPL_LISTEND);
845	}