trunk/src/ipcache.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2018 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 ipcache.c
 * \brief Routines to count connections from particular IP addresses.
 * \version $Id$
 */

#include "stdinc.h"
#include "list.h"
#include "ipcache.h"
#include "event.h"
#include "mempool.h"
#include "conf.h"
#include "ircd.h"


static dlink_list ip_hash_table[IP_HASH_SIZE];
static mp_pool_t *ip_entry_pool;


/* ipcache_hash_address()
 *
 * input        - pointer to an irc_inaddr
 * output       - integer value used as index into hash table
 * side effects - hopefully, none
 */
static uint32_t
ipcache_hash_address(const struct irc_ssaddr *addr)
{
  if (addr->ss.ss_family == AF_INET)
  {
    const struct sockaddr_in *const v4 = (const struct sockaddr_in *)addr;
    uint32_t hash = 0, ip = ntohl(v4->sin_addr.s_addr);

    hash = ((ip >> 12) + ip) & (IP_HASH_SIZE - 1);
    return hash;
  }
  else
  {
    const struct sockaddr_in6 *const v6 = (const struct sockaddr_in6 *)addr;
    uint32_t hash = 0, *const ip = (uint32_t *)&v6->sin6_addr.s6_addr;

    hash  = ip[0] ^ ip[3];
    hash ^= hash >> 16;
    hash ^= hash >> 8;
    hash  = hash & (IP_HASH_SIZE - 1);
    return hash;
  }
}

/* ipcache_find_or_add_address()
 *
 * inputs       - pointer to struct irc_ssaddr
 * output       - pointer to a struct ip_entry
 * side effects -
 *
 * If the ip # was not found, a new struct ip_entry is created, and the ip
 * count set to 0.
 */
struct ip_entry *
ipcache_find_or_add_address(const struct irc_ssaddr *addr)
{
  dlink_node *node;
  const uint32_t hash_index = ipcache_hash_address(addr);
  const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr, *ptr_v4;
  const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr, *ptr_v6;

  DLINK_FOREACH(node, ip_hash_table[hash_index].head)
  {
    struct ip_entry *iptr = node->data;

    if (iptr->ip.ss.ss_family != addr->ss.ss_family)
      continue;

    if (addr->ss.ss_family == AF_INET6)
    {
      ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
      if (!memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
        return iptr;  /* Found entry already in hash, return it. */
    }
    else
    {
      ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
      if (!memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
        return iptr;  /* Found entry already in hash, return it. */
    }
  }

  struct ip_entry *iptr = mp_pool_get(ip_entry_pool);
  memcpy(&iptr->ip, addr, sizeof(struct irc_ssaddr));

  dlinkAdd(iptr, &iptr->node, &ip_hash_table[hash_index]);

  return iptr;
}

/* ipcache_remove_addres()
 *
 * inputs        - unsigned long IP address value
 * output        - NONE
 * side effects  - The ip address given, is looked up in ip hash table
 *                 and number of ip#'s for that ip decremented.
 *                 If ip # count reaches 0 and has expired,
 *                 the struct ip_entry is returned to the ip_entry_heap
 */
void
ipcache_remove_address(const struct irc_ssaddr *addr)
{
  dlink_node *node;
  const uint32_t hash_index = ipcache_hash_address(addr);
  const struct sockaddr_in *v4 = (const struct sockaddr_in *)addr, *ptr_v4;
  const struct sockaddr_in6 *v6 = (const struct sockaddr_in6 *)addr, *ptr_v6;

  DLINK_FOREACH(node, ip_hash_table[hash_index].head)
  {
    struct ip_entry *iptr = node->data;

    if (iptr->ip.ss.ss_family != addr->ss.ss_family)
      continue;

    if (addr->ss.ss_family == AF_INET6)
    {
      ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
      if (memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
        continue;
    }
    else
    {
      ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
      if (memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
        continue;
    }

    assert(iptr->count > 0);

    if (--iptr->count == 0 &&
        (CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
    {
      dlinkDelete(&iptr->node, &ip_hash_table[hash_index]);
      mp_pool_release(iptr);
      return;
    }
  }
}

/* ipcache_remove_expired_entries()
 *
 * input        - NONE
 * output       - NONE
 * side effects - free up all ip entries with no connections
 */
static void
ipcache_remove_expired_entries(void *unused)
{
  dlink_node *node, *node_next;

  for (unsigned int i = 0; i < IP_HASH_SIZE; ++i)
  {
    DLINK_FOREACH_SAFE(node, node_next, ip_hash_table[i].head)
    {
      struct ip_entry *iptr = node->data;

      if (iptr->count == 0 &&
          (CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
      {
        dlinkDelete(&iptr->node, &ip_hash_table[i]);
        mp_pool_release(iptr);
      }
    }
  }
}

/* ipcache_get_stats()
 *
 * inputs        - pointer to counter of number of ips hashed
 *               - pointer to memory used for ip hash
 * output        - returned via pointers input
 * side effects  - NONE
 *
 * number of hashed ip #'s is counted up, plus the amount of memory
 * used in the hash.
 */
void
ipcache_get_stats(unsigned int *const number_ips_stored, size_t *const mem_ips_stored)
{
  for (unsigned int i = 0; i < IP_HASH_SIZE; ++i)
    *number_ips_stored += dlink_list_length(&ip_hash_table[i]);
  *mem_ips_stored = *number_ips_stored * sizeof(struct ip_entry);
}

void
ipcache_init(void)
{
  static struct event event_expire_ipcache =
  {
    .name = "ipcache_remove_expired_entries",
    .handler = ipcache_remove_expired_entries,
    .when = 123
  };

  event_add(&event_expire_ipcache, NULL);
  ip_entry_pool = mp_pool_new(sizeof(struct ip_entry), MP_CHUNK_SIZE_IP_ENTRY);
}
Revision:	8349
Committed:	Sun Mar 4 13:24:03 2018 UTC (7 years, 5 months ago) by michael
Content type:	text/x-csrc
File size:	6387 byte(s)
Log Message:	- Style corrections
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2018 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 ipcache.c
23	* \brief Routines to count connections from particular IP addresses.
24	* \version $Id$
25	*/
26
27	#include "stdinc.h"
28	#include "list.h"
29	#include "ipcache.h"
30	#include "event.h"
31	#include "mempool.h"
32	#include "conf.h"
33	#include "ircd.h"
34
35
36	static dlink_list ip_hash_table[IP_HASH_SIZE];
37	static mp_pool_t *ip_entry_pool;
38
39
40	/* ipcache_hash_address()
41	*
42	* input - pointer to an irc_inaddr
43	* output - integer value used as index into hash table
44	* side effects - hopefully, none
45	*/
46	static uint32_t
47	ipcache_hash_address(const struct irc_ssaddr *addr)
48	{
49	if (addr->ss.ss_family == AF_INET)
50	{
51	const struct sockaddr_in const v4 = (const struct sockaddr_in )addr;
52	uint32_t hash = 0, ip = ntohl(v4->sin_addr.s_addr);
53
54	hash = ((ip >> 12) + ip) & (IP_HASH_SIZE - 1);
55	return hash;
56	}
57	else
58	{
59	const struct sockaddr_in6 const v6 = (const struct sockaddr_in6 )addr;
60	uint32_t hash = 0, const ip = (uint32_t )&v6->sin6_addr.s6_addr;
61
62	hash = ip[0] ^ ip[3];
63	hash ^= hash >> 16;
64	hash ^= hash >> 8;
65	hash = hash & (IP_HASH_SIZE - 1);
66	return hash;
67	}
68	}
69
70	/* ipcache_find_or_add_address()
71	*
72	* inputs - pointer to struct irc_ssaddr
73	* output - pointer to a struct ip_entry
74	* side effects -
75	*
76	* If the ip # was not found, a new struct ip_entry is created, and the ip
77	* count set to 0.
78	*/
79	struct ip_entry *
80	ipcache_find_or_add_address(const struct irc_ssaddr *addr)
81	{
82	dlink_node *node;
83	const uint32_t hash_index = ipcache_hash_address(addr);
84	const struct sockaddr_in v4 = (const struct sockaddr_in )addr, *ptr_v4;
85	const struct sockaddr_in6 v6 = (const struct sockaddr_in6 )addr, *ptr_v6;
86
87	DLINK_FOREACH(node, ip_hash_table[hash_index].head)
88	{
89	struct ip_entry *iptr = node->data;
90
91	if (iptr->ip.ss.ss_family != addr->ss.ss_family)
92	continue;
93
94	if (addr->ss.ss_family == AF_INET6)
95	{
96	ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
97	if (!memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
98	return iptr; /* Found entry already in hash, return it. */
99	}
100	else
101	{
102	ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
103	if (!memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
104	return iptr; /* Found entry already in hash, return it. */
105	}
106	}
107
108	struct ip_entry *iptr = mp_pool_get(ip_entry_pool);
109	memcpy(&iptr->ip, addr, sizeof(struct irc_ssaddr));
110
111	dlinkAdd(iptr, &iptr->node, &ip_hash_table[hash_index]);
112
113	return iptr;
114	}
115
116	/* ipcache_remove_addres()
117	*
118	* inputs - unsigned long IP address value
119	* output - NONE
120	* side effects - The ip address given, is looked up in ip hash table
121	* and number of ip#'s for that ip decremented.
122	* If ip # count reaches 0 and has expired,
123	* the struct ip_entry is returned to the ip_entry_heap
124	*/
125	void
126	ipcache_remove_address(const struct irc_ssaddr *addr)
127	{
128	dlink_node *node;
129	const uint32_t hash_index = ipcache_hash_address(addr);
130	const struct sockaddr_in v4 = (const struct sockaddr_in )addr, *ptr_v4;
131	const struct sockaddr_in6 v6 = (const struct sockaddr_in6 )addr, *ptr_v6;
132
133	DLINK_FOREACH(node, ip_hash_table[hash_index].head)
134	{
135	struct ip_entry *iptr = node->data;
136
137	if (iptr->ip.ss.ss_family != addr->ss.ss_family)
138	continue;
139
140	if (addr->ss.ss_family == AF_INET6)
141	{
142	ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
143	if (memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
144	continue;
145	}
146	else
147	{
148	ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
149	if (memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
150	continue;
151	}
152
153	assert(iptr->count > 0);
154
155	if (--iptr->count == 0 &&
156	(CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
157	{
158	dlinkDelete(&iptr->node, &ip_hash_table[hash_index]);
159	mp_pool_release(iptr);
160	return;
161	}
162	}
163	}
164
165	/* ipcache_remove_expired_entries()
166	*
167	* input - NONE
168	* output - NONE
169	* side effects - free up all ip entries with no connections
170	*/
171	static void
172	ipcache_remove_expired_entries(void *unused)
173	{
174	dlink_node node, node_next;
175
176	for (unsigned int i = 0; i < IP_HASH_SIZE; ++i)
177	{
178	DLINK_FOREACH_SAFE(node, node_next, ip_hash_table[i].head)
179	{
180	struct ip_entry *iptr = node->data;
181
182	if (iptr->count == 0 &&
183	(CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
184	{
185	dlinkDelete(&iptr->node, &ip_hash_table[i]);
186	mp_pool_release(iptr);
187	}
188	}
189	}
190	}
191
192	/* ipcache_get_stats()
193	*
194	* inputs - pointer to counter of number of ips hashed
195	* - pointer to memory used for ip hash
196	* output - returned via pointers input
197	* side effects - NONE
198	*
199	* number of hashed ip #'s is counted up, plus the amount of memory
200	* used in the hash.
201	*/
202	void
203	ipcache_get_stats(unsigned int const number_ips_stored, size_t const mem_ips_stored)
204	{
205	for (unsigned int i = 0; i < IP_HASH_SIZE; ++i)
206	*number_ips_stored += dlink_list_length(&ip_hash_table[i]);
207	mem_ips_stored = number_ips_stored * sizeof(struct ip_entry);
208	}
209
210	void
211	ipcache_init(void)
212	{
213	static struct event event_expire_ipcache =
214	{
215	.name = "ipcache_remove_expired_entries",
216	.handler = ipcache_remove_expired_entries,
217	.when = 123
218	};
219
220	event_add(&event_expire_ipcache, NULL);
221	ip_entry_pool = mp_pool_new(sizeof(struct ip_entry), MP_CHUNK_SIZE_IP_ENTRY);
222	}