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 (8 years, 7 months ago) by michael
Content type:	text/x-csrc
File size:	6387 byte(s)
Log Message:	- Style corrections
#	User	Rev	Content
1	michael	4325	/*
2			* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3			*
4	michael	8279	* Copyright (c) 1997-2018 ircd-hybrid development team
5	michael	4325	*
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	michael	4565	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	michael	4325	* USA
20			*/
21
22			/*! \file ipcache.c
23			* \brief Routines to count connections from particular IP addresses.
24	michael	4327	* \version $Id$
25	michael	4325	*/
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	michael	4977	const struct sockaddr_in const v4 = (const struct sockaddr_in )addr;
52	michael	4325	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	michael	4977	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	michael	4325
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	michael	6651	ipcache_find_or_add_address(const struct irc_ssaddr *addr)
81	michael	4325	{
82	michael	8349	dlink_node *node;
83	michael	4977	const uint32_t hash_index = ipcache_hash_address(addr);
84	michael	6651	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	michael	4325
87	michael	4800	DLINK_FOREACH(node, ip_hash_table[hash_index].head)
88	michael	4325	{
89	michael	8349	struct ip_entry *iptr = node->data;
90	michael	4415
91	michael	4325	if (iptr->ip.ss.ss_family != addr->ss.ss_family)
92			continue;
93
94			if (addr->ss.ss_family == AF_INET6)
95			{
96	michael	6651	ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
97	michael	4367	if (!memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
98			return iptr; /* Found entry already in hash, return it. */
99	michael	4325	}
100			else
101			{
102	michael	6651	ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
103	michael	4367	if (!memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
104			return iptr; /* Found entry already in hash, return it. */
105	michael	4325	}
106			}
107
108	michael	8349	struct ip_entry *iptr = mp_pool_get(ip_entry_pool);
109	michael	4325	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	michael	6651	ipcache_remove_address(const struct irc_ssaddr *addr)
127	michael	4325	{
128	michael	8349	dlink_node *node;
129	michael	4977	const uint32_t hash_index = ipcache_hash_address(addr);
130	michael	6651	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	michael	4325
133	michael	4800	DLINK_FOREACH(node, ip_hash_table[hash_index].head)
134	michael	4325	{
135	michael	4800	struct ip_entry *iptr = node->data;
136	michael	4415
137	michael	4325	if (iptr->ip.ss.ss_family != addr->ss.ss_family)
138			continue;
139	michael	4367
140	michael	4325	if (addr->ss.ss_family == AF_INET6)
141			{
142	michael	6651	ptr_v6 = (const struct sockaddr_in6 *)&iptr->ip;
143	michael	4367	if (memcmp(&v6->sin6_addr, &ptr_v6->sin6_addr, sizeof(struct in6_addr)))
144			continue;
145	michael	4325	}
146			else
147			{
148	michael	6651	ptr_v4 = (const struct sockaddr_in *)&iptr->ip;
149	michael	4367	if (memcmp(&v4->sin_addr, &ptr_v4->sin_addr, sizeof(struct in_addr)))
150			continue;
151	michael	4325	}
152
153			assert(iptr->count > 0);
154
155			if (--iptr->count == 0 &&
156	michael	4340	(CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
157	michael	4325	{
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	michael	8349	dlink_node node, node_next;
175	michael	4325
176			for (unsigned int i = 0; i < IP_HASH_SIZE; ++i)
177			{
178	michael	4800	DLINK_FOREACH_SAFE(node, node_next, ip_hash_table[i].head)
179	michael	4325	{
180	michael	4800	struct ip_entry *iptr = node->data;
181	michael	4325
182			if (iptr->count == 0 &&
183	michael	4340	(CurrentTime - iptr->last_attempt) >= ConfigGeneral.throttle_time)
184	michael	4325	{
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	michael	6719	ipcache_get_stats(unsigned int const number_ips_stored, size_t const mem_ips_stored)
204	michael	4325	{
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			}