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/* Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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, see <https://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <stdlib.h>
#include <time.h>
#include "unreachable.h"
knot_unreachables_t *global_unreachables = NULL;
static uint32_t get_timestamp(void)
{
struct timespec t;
clock_gettime(CLOCK_MONOTONIC, &t);
uint64_t res = (uint64_t)t.tv_sec * 1000;
res += (uint64_t)t.tv_nsec / 1000000;
return res & 0xffffffff; // overflow does not matter since we are working with differences
}
knot_unreachables_t *knot_unreachables_init(uint32_t ttl_ms)
{
knot_unreachables_t *res = calloc(1, sizeof(*res));
if (res != NULL) {
pthread_mutex_init(&res->mutex, NULL);
res->ttl_ms = ttl_ms;
init_list(&res->urs);
}
return res;
}
uint32_t knot_unreachables_ttl(knot_unreachables_t *urs, uint32_t new_ttl_ms)
{
if (urs == NULL) {
return 0;
}
pthread_mutex_lock(&urs->mutex);
uint32_t prev = urs->ttl_ms;
urs->ttl_ms = new_ttl_ms;
pthread_mutex_unlock(&urs->mutex);
return prev;
}
void knot_unreachables_deinit(knot_unreachables_t **urs)
{
if (urs != NULL && *urs != NULL) {
knot_unreachable_t *ur, *nxt;
WALK_LIST_DELSAFE(ur, nxt, (*urs)->urs) {
rem_node((node_t *)ur);
free(ur);
}
pthread_mutex_destroy(&(*urs)->mutex);
free(*urs);
*urs = NULL;
}
}
static bool clear_old(knot_unreachable_t *ur, uint32_t now, uint32_t ttl_ms)
{
if (ur->time_ms != 0 && now - ur->time_ms > ttl_ms) {
rem_node((node_t *)ur);
free(ur);
return true;
}
return false;
}
// also clears up (some) expired unreachables
static knot_unreachable_t *get_ur(knot_unreachables_t *urs,
const struct sockaddr_storage *addr,
const struct sockaddr_storage *via)
{
assert(urs != NULL);
uint32_t now = get_timestamp();
knot_unreachable_t *ur, *nxt;
WALK_LIST_DELSAFE(ur, nxt, urs->urs) {
if (clear_old(ur, now, urs->ttl_ms)) {
continue;
}
if (sockaddr_cmp(&ur->addr, addr, false) == 0 &&
sockaddr_cmp(&ur->via, via, true) == 0) {
return ur;
}
}
return NULL;
}
bool knot_unreachable_is(knot_unreachables_t *urs,
const struct sockaddr_storage *addr,
const struct sockaddr_storage *via)
{
if (urs == NULL) {
return false;
}
assert(addr);
assert(via);
pthread_mutex_lock(&urs->mutex);
bool res = (get_ur(urs, addr, via) != NULL);
pthread_mutex_unlock(&urs->mutex);
return res;
}
void knot_unreachable_add(knot_unreachables_t *urs,
const struct sockaddr_storage *addr,
const struct sockaddr_storage *via)
{
if (urs == NULL) {
return;
}
assert(addr);
assert(via);
pthread_mutex_lock(&urs->mutex);
knot_unreachable_t *ur = malloc(sizeof(*ur));
if (ur != NULL) {
memcpy(&ur->addr, addr, sizeof(ur->addr));
memcpy(&ur->via, via, sizeof(ur->via));
ur->time_ms = get_timestamp();
add_head(&urs->urs, (node_t *)ur);
}
pthread_mutex_unlock(&urs->mutex);
}
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