17c8de633f
When we return the full RR wire data, let's make sure the TTL included in it is adjusted by the time the RR sat in the cache. As an optimization we do this only for ResolveRecord() and not for ResolveHostname() and friends, since adjusting the TTL means copying the RR object, and we don#t want to do that if there's no reason to. (ResolveHostname() and friends don't return the TTL hence there's no reason to in that case)
238 lines
5.5 KiB
C
238 lines
5.5 KiB
C
/***
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This file is part of systemd.
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Copyright 2015 Tom Gundersen
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include "alloc-util.h"
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#include "bitmap.h"
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#include "hashmap.h"
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#include "macro.h"
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struct Bitmap {
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uint64_t *bitmaps;
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size_t n_bitmaps;
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size_t bitmaps_allocated;
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};
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/* Bitmaps are only meant to store relatively small numbers
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* (corresponding to, say, an enum), so it is ok to limit
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* the max entry. 64k should be plenty. */
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#define BITMAPS_MAX_ENTRY 0xffff
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/* This indicates that we reached the end of the bitmap */
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#define BITMAP_END ((unsigned) -1)
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#define BITMAP_NUM_TO_OFFSET(n) ((n) / (sizeof(uint64_t) * 8))
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#define BITMAP_NUM_TO_REM(n) ((n) % (sizeof(uint64_t) * 8))
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#define BITMAP_OFFSET_TO_NUM(offset, rem) ((offset) * sizeof(uint64_t) * 8 + (rem))
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Bitmap *bitmap_new(void) {
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return new0(Bitmap, 1);
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}
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Bitmap *bitmap_copy(Bitmap *b) {
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Bitmap *ret;
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ret = bitmap_new();
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if (!ret)
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return NULL;
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ret->bitmaps = newdup(uint64_t, b->bitmaps, b->n_bitmaps);
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if (!ret->bitmaps) {
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free(ret);
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return NULL;
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}
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ret->n_bitmaps = ret->bitmaps_allocated = b->n_bitmaps;
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return ret;
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}
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void bitmap_free(Bitmap *b) {
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if (!b)
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return;
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free(b->bitmaps);
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free(b);
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}
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int bitmap_ensure_allocated(Bitmap **b) {
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Bitmap *a;
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assert(b);
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if (*b)
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return 0;
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a = bitmap_new();
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if (!a)
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return -ENOMEM;
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*b = a;
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return 0;
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}
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int bitmap_set(Bitmap *b, unsigned n) {
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uint64_t bitmask;
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unsigned offset;
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assert(b);
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/* we refuse to allocate huge bitmaps */
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if (n > BITMAPS_MAX_ENTRY)
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return -ERANGE;
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offset = BITMAP_NUM_TO_OFFSET(n);
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if (offset >= b->n_bitmaps) {
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if (!GREEDY_REALLOC0(b->bitmaps, b->bitmaps_allocated, offset + 1))
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return -ENOMEM;
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b->n_bitmaps = offset + 1;
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}
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bitmask = UINT64_C(1) << BITMAP_NUM_TO_REM(n);
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b->bitmaps[offset] |= bitmask;
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return 0;
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}
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void bitmap_unset(Bitmap *b, unsigned n) {
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uint64_t bitmask;
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unsigned offset;
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if (!b)
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return;
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offset = BITMAP_NUM_TO_OFFSET(n);
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if (offset >= b->n_bitmaps)
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return;
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bitmask = UINT64_C(1) << BITMAP_NUM_TO_REM(n);
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b->bitmaps[offset] &= ~bitmask;
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}
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bool bitmap_isset(Bitmap *b, unsigned n) {
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uint64_t bitmask;
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unsigned offset;
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if (!b)
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return false;
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offset = BITMAP_NUM_TO_OFFSET(n);
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if (offset >= b->n_bitmaps)
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return false;
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bitmask = UINT64_C(1) << BITMAP_NUM_TO_REM(n);
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return !!(b->bitmaps[offset] & bitmask);
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}
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bool bitmap_isclear(Bitmap *b) {
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unsigned i;
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if (!b)
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return true;
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for (i = 0; i < b->n_bitmaps; i++)
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if (b->bitmaps[i] != 0)
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return false;
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return true;
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}
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void bitmap_clear(Bitmap *b) {
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if (!b)
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return;
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b->bitmaps = mfree(b->bitmaps);
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b->n_bitmaps = 0;
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b->bitmaps_allocated = 0;
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}
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bool bitmap_iterate(Bitmap *b, Iterator *i, unsigned *n) {
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uint64_t bitmask;
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unsigned offset, rem;
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assert(i);
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assert(n);
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if (!b || i->idx == BITMAP_END)
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return false;
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offset = BITMAP_NUM_TO_OFFSET(i->idx);
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rem = BITMAP_NUM_TO_REM(i->idx);
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bitmask = UINT64_C(1) << rem;
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for (; offset < b->n_bitmaps; offset ++) {
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if (b->bitmaps[offset]) {
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for (; bitmask; bitmask <<= 1, rem ++) {
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if (b->bitmaps[offset] & bitmask) {
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*n = BITMAP_OFFSET_TO_NUM(offset, rem);
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i->idx = *n + 1;
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return true;
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}
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}
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}
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rem = 0;
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bitmask = 1;
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}
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i->idx = BITMAP_END;
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return false;
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}
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bool bitmap_equal(Bitmap *a, Bitmap *b) {
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size_t common_n_bitmaps;
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Bitmap *c;
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unsigned i;
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if (a == b)
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return true;
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if (!a != !b)
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return false;
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if (!a)
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return true;
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common_n_bitmaps = MIN(a->n_bitmaps, b->n_bitmaps);
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if (memcmp(a->bitmaps, b->bitmaps, sizeof(uint64_t) * common_n_bitmaps) != 0)
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return false;
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c = a->n_bitmaps > b->n_bitmaps ? a : b;
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for (i = common_n_bitmaps; i < c->n_bitmaps; i++)
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if (c->bitmaps[i] != 0)
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return false;
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return true;
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}
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