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ip_set_iphash.c

/* Copyright (C) 2003-2008 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/* Kernel module implementing an ip hash set */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include "ip_set_jhash.h"
#include <linux/errno.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>
#include <linux/spinlock.h>
#include <linux/random.h>

#include <net/ip.h>

#include "ip_set_iphash.h"

static int limit = MAX_RANGE;

static inline __u32
iphash_id(struct ip_set *set, ip_set_ip_t ip)
{
      struct ip_set_iphash *map = set->data;
      __u32 id;
      u_int16_t i;
      ip_set_ip_t *elem;


      ip &= map->netmask;     
      DP("set: %s, ip:%u.%u.%u.%u", set->name, HIPQUAD(ip));
      for (i = 0; i < map->probes; i++) {
            id = jhash_ip(map, i, ip) % map->hashsize;
            DP("hash key: %u", id);
            elem = HARRAY_ELEM(map->members, ip_set_ip_t *, id);
            if (*elem == ip)
                  return id;
            /* No shortcut - there can be deleted entries. */
      }
      return UINT_MAX;
}

static inline int
iphash_test(struct ip_set *set, ip_set_ip_t ip)
{
      return (ip && iphash_id(set, ip) != UINT_MAX);
}

#define KADT_CONDITION

UADT(iphash, test)
KADT(iphash, test, ipaddr)

static inline int
__iphash_add(struct ip_set_iphash *map, ip_set_ip_t *ip)
{
      __u32 probe;
      u_int16_t i;
      ip_set_ip_t *elem, *slot = NULL;
      
      for (i = 0; i < map->probes; i++) {
            probe = jhash_ip(map, i, *ip) % map->hashsize;
            elem = HARRAY_ELEM(map->members, ip_set_ip_t *, probe);
            if (*elem == *ip)
                  return -EEXIST;
            if (!(slot || *elem))
                  slot = elem;
            /* There can be deleted entries, must check all slots */
      }
      if (slot) {
            *slot = *ip;
            map->elements++;
            return 0;
      }
      /* Trigger rehashing */
      return -EAGAIN;
}

static inline int
iphash_add(struct ip_set *set, ip_set_ip_t ip)
{
      struct ip_set_iphash *map = set->data;
      
      if (!ip || map->elements >= limit)
            return -ERANGE;

      ip &= map->netmask;
      return __iphash_add(map, &ip);
}

UADT(iphash, add)
KADT(iphash, add, ipaddr)

static inline void
__iphash_retry(struct ip_set_iphash *tmp, struct ip_set_iphash *map)
{
      tmp->netmask = map->netmask;
}

HASH_RETRY(iphash, ip_set_ip_t)

static inline int
iphash_del(struct ip_set *set, ip_set_ip_t ip)
{
      struct ip_set_iphash *map = set->data;
      ip_set_ip_t id, *elem;

      if (!ip)
            return -ERANGE;

      id = iphash_id(set, ip);
      if (id == UINT_MAX)
            return -EEXIST;
            
      elem = HARRAY_ELEM(map->members, ip_set_ip_t *, id);
      *elem = 0;
      map->elements--;

      return 0;
}

UADT(iphash, del)
KADT(iphash, del, ipaddr)

static inline int
__iphash_create(const struct ip_set_req_iphash_create *req,
            struct ip_set_iphash *map)
{
      map->netmask = req->netmask;
      
      return 0;
}

HASH_CREATE(iphash, ip_set_ip_t)
HASH_DESTROY(iphash)

HASH_FLUSH(iphash, ip_set_ip_t)

static inline void
__iphash_list_header(const struct ip_set_iphash *map,
                 struct ip_set_req_iphash_create *header)
{    
      header->netmask = map->netmask;
}

HASH_LIST_HEADER(iphash)
HASH_LIST_MEMBERS_SIZE(iphash, ip_set_ip_t)
HASH_LIST_MEMBERS(iphash, ip_set_ip_t)

IP_SET_RTYPE(iphash, IPSET_TYPE_IP | IPSET_DATA_SINGLE)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
MODULE_DESCRIPTION("iphash type of IP sets");
module_param(limit, int, 0600);
MODULE_PARM_DESC(limit, "maximal number of elements stored in the sets");

REGISTER_MODULE(iphash)

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