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-rw-r--r--utils/cache_gc/db.c280
1 files changed, 280 insertions, 0 deletions
diff --git a/utils/cache_gc/db.c b/utils/cache_gc/db.c
new file mode 100644
index 0000000..fc4a2fd
--- /dev/null
+++ b/utils/cache_gc/db.c
@@ -0,0 +1,280 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include "db.h"
+
+#include "lib/cache/cdb_lmdb.h"
+#include "lib/cache/impl.h"
+
+#include <ctype.h>
+#include <time.h>
+#include <sys/stat.h>
+
+int kr_gc_cache_open(const char *cache_path, struct kr_cache *kres_db,
+ knot_db_t ** libknot_db)
+{
+ char cache_data[strlen(cache_path) + 10];
+ snprintf(cache_data, sizeof(cache_data), "%s/data.mdb", cache_path);
+
+ struct stat st = { 0 };
+ if (stat(cache_path, &st) || !(st.st_mode & S_IFDIR)
+ || stat(cache_data, &st)) {
+ printf("Error: %s does not exist or is not a LMDB.\n", cache_path);
+ return -ENOENT;
+ }
+
+ struct kr_cdb_opts opts = { .path = cache_path, .maxsize = 0/*don't resize*/ };
+
+ int ret = kr_cache_open(kres_db, NULL, &opts, NULL);
+ if (ret || kres_db->db == NULL) {
+ printf("Error opening Resolver cache (%s).\n", kr_strerror(ret));
+ return -EINVAL;
+ }
+
+ *libknot_db = kr_cdb_pt2knot_db_t(kres_db->db);
+ if (*libknot_db == NULL) {
+ printf("Out of memory.\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+int kr_gc_cache_check_health(struct kr_cache *kres_db, knot_db_t ** libknot_db)
+{
+ int ret = kr_cache_check_health(kres_db, 0);
+ if (ret == 0) {
+ return 0;
+ } else if (ret != 1) {
+ kr_gc_cache_close(kres_db, *libknot_db);
+ return ret;
+ }
+ /* Cache was reopen. */
+ free(*libknot_db);
+ *libknot_db = kr_cdb_pt2knot_db_t(kres_db->db);
+ if (*libknot_db == NULL) {
+ printf("Out of memory.\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+void kr_gc_cache_close(struct kr_cache *kres_db, knot_db_t * knot_db)
+{
+ free(knot_db);
+ kr_cache_close(kres_db);
+}
+
+int kr_gc_key_consistent(knot_db_val_t key)
+{
+ const uint8_t *kd = key.data;
+ ssize_t i;
+ /* CACHE_KEY_DEF */
+ if (key.len >= 2 && kd[0] == '\0') {
+ /* Beware: root zone is special and starts with
+ * a single \0 followed by type sign */
+ i = 1;
+ } else {
+ /* find the first double zero in the key */
+ for (i = 2; kd[i - 1] || kd[i - 2]; ++i) {
+ if (kr_fails_assert(i < key.len))
+ return kr_error(EINVAL);
+ }
+ }
+ // the next character can be used for classification
+ switch (kd[i]) {
+ case 'E':
+ (void)0; // C can't have a variable definition following a label
+ uint16_t type;
+ if (kr_fails_assert(i + 1 + sizeof(type) <= key.len))
+ return kr_error(EINVAL);
+ memcpy(&type, kd + i + 1, sizeof(type));
+ return type;
+ case '1':
+ return KNOT_RRTYPE_NSEC;
+ case '3':
+ return KNOT_RRTYPE_NSEC3;
+ case 'S': // the rtt_state entries are considered inconsistent, at least for now
+ return -1;
+ default:
+ kr_assert(!EINVAL);
+ return kr_error(EINVAL);
+ }
+}
+
+/// expects that key is consistent! CACHE_KEY_DEF
+static uint8_t entry_labels(knot_db_val_t * key, uint16_t rrtype)
+{
+ uint8_t lab = 0, *p = key->data;
+ while (*p != 0) {
+ while (*p++ != 0) {
+ if (p - (uint8_t *) key->data >= key->len) {
+ return 0;
+ }
+ }
+ lab++;
+ }
+ if (rrtype == KNOT_RRTYPE_NSEC3) {
+ // We don't know the number of labels so easily,
+ // but let's classify everything as directly
+ // below the zone apex (that's most common).
+ ++lab;
+ }
+ return lab;
+}
+
+void debug_printbin(const char *str, unsigned int len)
+{
+ putchar('"');
+ for (int idx = 0; idx < len; idx++) {
+ char c = str[idx];
+ if (isprint(c))
+ putchar(c);
+ else
+ printf("`%02hhx`", c);
+ }
+ putchar('"');
+}
+
+/** Return one entry_h reference from a cache DB value. NULL if not consistent/suitable. */
+static const struct entry_h *val2entry(const knot_db_val_t val, uint16_t ktype)
+{
+ if (ktype != KNOT_RRTYPE_NS)
+ return entry_h_consistent(val, ktype);
+ /* Otherwise we have a multi-purpose entry.
+ * Well, for now we simply choose the most suitable entry;
+ * the only realistic collision is DNAME in apex where we'll prefer NS. */
+ entry_list_t el;
+ if (entry_list_parse(val, el))
+ return NULL;
+ for (int i = ENTRY_APEX_NSECS_CNT; i < EL_LENGTH; ++i) {
+ if (el[i].len)
+ return entry_h_consistent(el[i], EL2RRTYPE(i));
+ }
+ /* Only NSEC* meta-data inside. */
+ return NULL;
+}
+
+int kr_gc_cache_iter(knot_db_t * knot_db, const kr_cache_gc_cfg_t *cfg,
+ kr_gc_iter_callback callback, void *ctx)
+{
+ unsigned int counter_iter = 0;
+ unsigned int counter_gc_consistent = 0;
+ unsigned int counter_kr_consistent = 0;
+
+ knot_db_txn_t txn = { 0 };
+ knot_db_iter_t *it = NULL;
+ const knot_db_api_t *api = knot_db_lmdb_api();
+ gc_record_info_t info = { 0 };
+ int64_t now = time(NULL);
+
+ int ret = api->txn_begin(knot_db, &txn, KNOT_DB_RDONLY);
+ if (ret != KNOT_EOK) {
+ printf("Error starting DB transaction (%s).\n", knot_strerror(ret));
+ return ret;
+ }
+
+ it = api->iter_begin(&txn, KNOT_DB_NOOP); // _FIRST is split for easier debugging
+ if (it == NULL) {
+ printf("Error: failed to create an iterator.\n");
+ api->txn_abort(&txn);
+ return KNOT_ERROR;
+ }
+ it = api->iter_seek(it, NULL, KNOT_DB_FIRST);
+ if (it == NULL)
+ printf("Suspicious: completely empty LMDB at this moment?\n");
+
+ int txn_steps = 0;
+ while (it != NULL) {
+ knot_db_val_t key = { 0 }, val = { 0 };
+ ret = api->iter_key(it, &key);
+ if (ret == KNOT_EOK && key.len == 4 && memcmp("VERS", key.data, 4) == 0) {
+ /* skip DB metadata */
+ goto skip;
+ }
+ if (ret == KNOT_EOK) {
+ ret = api->iter_val(it, &val);
+ }
+ if (ret != KNOT_EOK) {
+ goto error;
+ }
+
+ info.entry_size = key.len + val.len;
+ info.valid = false;
+ const int entry_type = kr_gc_key_consistent(key);
+ const struct entry_h *entry = NULL;
+ if (entry_type >= 0) {
+ counter_gc_consistent++;
+ entry = val2entry(val, entry_type);
+ }
+ /* TODO: perhaps improve some details around here:
+ * - rtt_state entries are considered gc_inconsistent;
+ * therefore they'll be the first to get freed (see kr_gc_categorize())
+ * - xNAME have .rrtype NS
+ * - DNAME hidden on NS name will not be considered here
+ * - if zone has NSEC* meta-data but no NS, it will be seen
+ * here as kr_inconsistent */
+ if (entry != NULL) {
+ info.valid = true;
+ info.rrtype = entry_type;
+ info.expires_in = entry->time + entry->ttl - now;
+ info.no_labels = entry_labels(&key, entry_type);
+ }
+ counter_iter++;
+ counter_kr_consistent += info.valid;
+ if (VERBOSE_STATUS) {
+ if (!entry_type || !entry) { // don't log fully consistent entries
+ printf
+ ("GC %sconsistent, KR %sconsistent, size %zu, key len %zu: ",
+ entry_type ? "" : "in", entry ? "" : "IN",
+ (key.len + val.len), key.len);
+ debug_printbin(key.data, key.len);
+ printf("\n");
+ }
+ }
+ ret = callback(&key, &info, ctx);
+
+ if (ret != KNOT_EOK) {
+ error:
+ printf("Error iterating database (%s).\n",
+ knot_strerror(ret));
+ api->iter_finish(it);
+ api->txn_abort(&txn);
+ return ret;
+ }
+
+ skip: // Advance to the next GC item.
+ if (++txn_steps < cfg->ro_txn_items || !cfg->ro_txn_items/*unlimited*/) {
+ it = api->iter_next(it);
+ } else {
+ /* The transaction has been too long; let's reopen it. */
+ txn_steps = 0;
+ uint8_t key_storage[key.len];
+ memcpy(key_storage, key.data, key.len);
+ key.data = key_storage;
+
+ api->iter_finish(it);
+ api->txn_abort(&txn);
+
+ ret = api->txn_begin(knot_db, &txn, KNOT_DB_RDONLY);
+ if (ret != KNOT_EOK) {
+ printf("Error restarting DB transaction (%s).\n",
+ knot_strerror(ret));
+ return ret;
+ }
+ it = api->iter_begin(&txn, KNOT_DB_NOOP);
+ if (it == NULL) {
+ printf("Error: failed to create an iterator.\n");
+ api->txn_abort(&txn);
+ return KNOT_ERROR;
+ }
+ it = api->iter_seek(it, &key, KNOT_DB_GEQ);
+ // NULL here means we'we reached the end
+ }
+ }
+
+ api->txn_abort(&txn);
+
+ kr_log_debug(CACHE, "iterated %u items, gc consistent %u, kr consistent %u\n",
+ counter_iter, counter_gc_consistent, counter_kr_consistent);
+ return KNOT_EOK;
+}
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