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/*
Copyright (C) 2017 Paweł Redman
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 3
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
*/
#include "shared.h"
#define HASH_MAX 4095
static size_t db_hash(uint32_t ipv4)
{
// FIXME: Use an academically acclaimed hashing algorithm.
return (((ipv4 >> 16) ^ ipv4) * 3137) & HASH_MAX;
}
db_entry *database[HASH_MAX];
pthread_mutex_t database_mutex = PTHREAD_MUTEX_INITIALIZER;
// Returns a pointer to the relevant db_entry (newly created if didn't exist).
// This function locks the db_entry's mutex before returning.
// Returns NULL if calloc fails.
db_entry *db_find(uint32_t ipv4)
{
size_t hash;
db_entry *entry;
hash = db_hash(ipv4);
pthread_mutex_lock(&database_mutex);
eli_for (entry, database[hash], ht_chain)
if (entry->ipv4 == ipv4)
break;
if (!entry) {
entry = calloc(1, sizeof(db_entry));
if (!entry)
goto out;
entry->ipv4 = ipv4;
pthread_mutex_init(&entry->mutex, NULL);
eli_append(database + hash, entry, ht_chain);
}
pthread_mutex_lock(&entry->mutex);
out:
pthread_mutex_unlock(&database_mutex);
return entry;
}
static void destroy_entry(db_entry *entry)
{
job_t *job, *next;
for (job = entry->waiting_jobs; job; job = next) {
next = job->waiting_list.next;
job_destroy(job);
}
free(entry);
}
// Frees all entries and resets the database.
void db_destroy(void)
{
size_t i;
db_entry *entry, *next;
pthread_mutex_lock(&database_mutex);
for (i = 0; i < HASH_MAX; i++) {
for (entry = database[i]; entry; entry = next) {
next = entry->ht_chain.next;
free(entry->revdns.data);
free(entry->whois.data);
destroy_entry(entry);
}
database[i] = NULL;
}
pthread_mutex_unlock(&database_mutex);
}
void db_invalidate_cached_results(void)
{
size_t i;
db_entry *entry;
pthread_mutex_lock(&database_mutex);
for (i = 0; i < HASH_MAX; i++)
eli_for(entry, database[i], ht_chain)
entry->cached_result_valid = false;
pthread_mutex_unlock(&database_mutex);
}
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