Update contrib/libs/c-ares to 1.28.1

db71d0a3bd9ec3cf1e1ccb5a9cfac8abfd43fdb7

1 files changed, 444 insertions, 0 deletions

diff --git a/contrib/libs/c-ares/src/lib/ares_qcache.c b/contrib/libs/c-ares/src/lib/ares_qcache.c
new file mode 100644
index 0000000000..2af1125a0d
--- /dev/null
+++ b/contrib/libs/c-ares/src/lib/ares_qcache.c
@@ -0,0 +1,444 @@
+/* MIT License
+ *
+ * Copyright (c) 2023 Brad House
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#include "ares_setup.h"
+#include "ares.h"
+#include "ares_private.h"
+
+struct ares__qcache {
+  ares__htable_strvp_t *cache;
+  ares__slist_t        *expire;
+  unsigned int          max_ttl;
+};
+
+typedef struct {
+  char              *key;
+  ares_dns_record_t *dnsrec;
+  time_t             expire_ts;
+  time_t             insert_ts;
+} ares__qcache_entry_t;
+
+static char *ares__qcache_calc_key(const ares_dns_record_t *dnsrec)
+{
+  ares__buf_t     *buf = ares__buf_create();
+  size_t           i;
+  ares_status_t    status;
+  ares_dns_flags_t flags;
+
+  if (dnsrec == NULL || buf == NULL) {
+    return NULL;
+  }
+
+  /* Format is OPCODE|FLAGS[|QTYPE1|QCLASS1|QNAME1]... */
+
+  status = ares__buf_append_str(
+    buf, ares_dns_opcode_tostr(ares_dns_record_get_opcode(dnsrec)));
+  if (status != ARES_SUCCESS) {
+    goto fail;
+  }
+
+  status = ares__buf_append_byte(buf, '|');
+  if (status != ARES_SUCCESS) {
+    goto fail;
+  }
+
+  flags = ares_dns_record_get_flags(dnsrec);
+  /* Only care about RD and CD */
+  if (flags & ARES_FLAG_RD) {
+    status = ares__buf_append_str(buf, "rd");
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+  }
+  if (flags & ARES_FLAG_CD) {
+    status = ares__buf_append_str(buf, "cd");
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+  }
+
+  for (i = 0; i < ares_dns_record_query_cnt(dnsrec); i++) {
+    const char         *name;
+    size_t              name_len;
+    ares_dns_rec_type_t qtype;
+    ares_dns_class_t    qclass;
+
+    status = ares_dns_record_query_get(dnsrec, i, &name, &qtype, &qclass);
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    status = ares__buf_append_byte(buf, '|');
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    status = ares__buf_append_str(buf, ares_dns_rec_type_tostr(qtype));
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    status = ares__buf_append_byte(buf, '|');
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    status = ares__buf_append_str(buf, ares_dns_class_tostr(qclass));
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    status = ares__buf_append_byte(buf, '|');
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+
+    /* On queries, a '.' may be appended to the name to indicate an explicit
+     * name lookup without performing a search.  Strip this since its not part
+     * of a cached response. */
+    name_len = ares_strlen(name);
+    if (name_len && name[name_len - 1] == '.') {
+      name_len--;
+    }
+
+    status = ares__buf_append(buf, (const unsigned char *)name, name_len);
+    if (status != ARES_SUCCESS) {
+      goto fail;
+    }
+  }
+
+  return ares__buf_finish_str(buf, NULL);
+
+fail:
+  ares__buf_destroy(buf);
+  return NULL;
+}
+
+static void ares__qcache_expire(ares__qcache_t       *cache,
+                                const struct timeval *now)
+{
+  ares__slist_node_t *node;
+
+  if (cache == NULL) {
+    return;
+  }
+
+  while ((node = ares__slist_node_first(cache->expire)) != NULL) {
+    const ares__qcache_entry_t *entry = ares__slist_node_val(node);
+    if (entry->expire_ts > now->tv_sec) {
+      break;
+    }
+
+    ares__htable_strvp_remove(cache->cache, entry->key);
+    ares__slist_node_destroy(node);
+  }
+}
+
+void ares__qcache_flush(ares__qcache_t *cache)
+{
+  struct timeval now;
+  memset(&now, 0, sizeof(now));
+  ares__qcache_expire(cache, &now);
+}
+
+void ares__qcache_destroy(ares__qcache_t *cache)
+{
+  if (cache == NULL) {
+    return;
+  }
+
+  ares__htable_strvp_destroy(cache->cache);
+  ares__slist_destroy(cache->expire);
+  ares_free(cache);
+}
+
+static int ares__qcache_entry_sort_cb(const void *arg1, const void *arg2)
+{
+  const ares__qcache_entry_t *entry1 = arg1;
+  const ares__qcache_entry_t *entry2 = arg2;
+
+  if (entry1->expire_ts > entry2->expire_ts) {
+    return 1;
+  }
+
+  if (entry1->expire_ts < entry2->expire_ts) {
+    return -1;
+  }
+
+  return 0;
+}
+
+static void ares__qcache_entry_destroy_cb(void *arg)
+{
+  ares__qcache_entry_t *entry = arg;
+  if (entry == NULL) {
+    return;
+  }
+
+  ares_free(entry->key);
+  ares_dns_record_destroy(entry->dnsrec);
+  ares_free(entry);
+}
+
+ares_status_t ares__qcache_create(ares_rand_state *rand_state,
+                                  unsigned int     max_ttl,
+                                  ares__qcache_t **cache_out)
+{
+  ares_status_t   status = ARES_SUCCESS;
+  ares__qcache_t *cache;
+
+  cache = ares_malloc_zero(sizeof(*cache));
+  if (cache == NULL) {
+    status = ARES_ENOMEM;
+    goto done;
+  }
+
+  cache->cache = ares__htable_strvp_create(NULL);
+  if (cache->cache == NULL) {
+    status = ARES_ENOMEM;
+    goto done;
+  }
+
+  cache->expire = ares__slist_create(rand_state, ares__qcache_entry_sort_cb,
+                                     ares__qcache_entry_destroy_cb);
+  if (cache->expire == NULL) {
+    status = ARES_ENOMEM;
+    goto done;
+  }
+
+  cache->max_ttl = max_ttl;
+
+done:
+  if (status != ARES_SUCCESS) {
+    *cache_out = NULL;
+    ares__qcache_destroy(cache);
+    return status;
+  }
+
+  *cache_out = cache;
+  return status;
+}
+
+static unsigned int ares__qcache_calc_minttl(ares_dns_record_t *dnsrec)
+{
+  unsigned int minttl = 0xFFFFFFFF;
+  size_t       sect;
+
+  for (sect = ARES_SECTION_ANSWER; sect <= ARES_SECTION_ADDITIONAL; sect++) {
+    size_t i;
+    for (i = 0; i < ares_dns_record_rr_cnt(dnsrec, (ares_dns_section_t)sect);
+         i++) {
+      const ares_dns_rr_t *rr =
+        ares_dns_record_rr_get(dnsrec, (ares_dns_section_t)sect, i);
+      ares_dns_rec_type_t type = ares_dns_rr_get_type(rr);
+      unsigned int        ttl  = ares_dns_rr_get_ttl(rr);
+      if (type == ARES_REC_TYPE_OPT || type == ARES_REC_TYPE_SOA) {
+        continue;
+      }
+
+      if (ttl < minttl) {
+        minttl = ttl;
+      }
+    }
+  }
+
+  return minttl;
+}
+
+static unsigned int ares__qcache_soa_minimum(ares_dns_record_t *dnsrec)
+{
+  size_t i;
+
+  /* RFC 2308 Section 5 says its the minimum of MINIMUM and the TTL of the
+   * record. */
+  for (i = 0; i < ares_dns_record_rr_cnt(dnsrec, ARES_SECTION_AUTHORITY); i++) {
+    const ares_dns_rr_t *rr =
+      ares_dns_record_rr_get(dnsrec, ARES_SECTION_AUTHORITY, i);
+    ares_dns_rec_type_t type = ares_dns_rr_get_type(rr);
+    unsigned int        ttl;
+    unsigned int        minimum;
+
+    if (type != ARES_REC_TYPE_SOA) {
+      continue;
+    }
+
+    minimum = ares_dns_rr_get_u32(rr, ARES_RR_SOA_MINIMUM);
+    ttl     = ares_dns_rr_get_ttl(rr);
+
+    if (ttl > minimum) {
+      return minimum;
+    }
+    return ttl;
+  }
+
+  return 0;
+}
+
+static char *ares__qcache_calc_key_frombuf(const unsigned char *qbuf,
+                                           size_t               qlen)
+{
+  ares_status_t      status;
+  ares_dns_record_t *dnsrec = NULL;
+  char              *key    = NULL;
+
+  status = ares_dns_parse(qbuf, qlen, 0, &dnsrec);
+  if (status != ARES_SUCCESS) {
+    goto done;
+  }
+
+  key = ares__qcache_calc_key(dnsrec);
+
+done:
+  ares_dns_record_destroy(dnsrec);
+  return key;
+}
+
+/* On success, takes ownership of dnsrec */
+static ares_status_t ares__qcache_insert(ares__qcache_t      *qcache,
+                                         ares_dns_record_t   *dnsrec,
+                                         const unsigned char *qbuf, size_t qlen,
+                                         const struct timeval *now)
+{
+  ares__qcache_entry_t *entry;
+  unsigned int          ttl;
+  ares_dns_rcode_t      rcode = ares_dns_record_get_rcode(dnsrec);
+  ares_dns_flags_t      flags = ares_dns_record_get_flags(dnsrec);
+
+  if (qcache == NULL || dnsrec == NULL) {
+    return ARES_EFORMERR;
+  }
+
+  /* Only save NOERROR or NXDOMAIN */
+  if (rcode != ARES_RCODE_NOERROR && rcode != ARES_RCODE_NXDOMAIN) {
+    return ARES_ENOTIMP;
+  }
+
+  /* Don't save truncated queries */
+  if (flags & ARES_FLAG_TC) {
+    return ARES_ENOTIMP;
+  }
+
+  /* Look at SOA for NXDOMAIN for minimum */
+  if (rcode == ARES_RCODE_NXDOMAIN) {
+    ttl = ares__qcache_soa_minimum(dnsrec);
+  } else {
+    ttl = ares__qcache_calc_minttl(dnsrec);
+  }
+
+  /* Don't cache something that is already expired */
+  if (ttl == 0) {
+    return ARES_EREFUSED;
+  }
+
+  if (ttl > qcache->max_ttl) {
+    ttl = qcache->max_ttl;
+  }
+
+  entry = ares_malloc_zero(sizeof(*entry));
+  if (entry == NULL) {
+    goto fail;
+  }
+
+  entry->dnsrec    = dnsrec;
+  entry->expire_ts = now->tv_sec + (time_t)ttl;
+  entry->insert_ts = now->tv_sec;
+
+  /* We can't guarantee the server responded with the same flags as the
+   * request had, so we have to re-parse the request in order to generate the
+   * key for caching, but we'll only do this once we know for sure we really
+   * want to cache it */
+  entry->key = ares__qcache_calc_key_frombuf(qbuf, qlen);
+  if (entry->key == NULL) {
+    goto fail;
+  }
+
+  if (!ares__htable_strvp_insert(qcache->cache, entry->key, entry)) {
+    goto fail;
+  }
+
+  if (ares__slist_insert(qcache->expire, entry) == NULL) {
+    goto fail;
+  }
+
+  return ARES_SUCCESS;
+
+fail:
+  if (entry != NULL && entry->key != NULL) {
+    ares__htable_strvp_remove(qcache->cache, entry->key);
+    ares_free(entry->key);
+    ares_free(entry);
+  }
+  return ARES_ENOMEM;
+}
+
+ares_status_t ares_qcache_fetch(ares_channel_t           *channel,
+                                const struct timeval     *now,
+                                const ares_dns_record_t  *dnsrec,
+                                const ares_dns_record_t **dnsrec_resp)
+{
+  char                 *key = NULL;
+  ares__qcache_entry_t *entry;
+  ares_status_t         status = ARES_SUCCESS;
+
+  if (channel == NULL || dnsrec == NULL || dnsrec_resp == NULL) {
+    return ARES_EFORMERR;
+  }
+
+  if (channel->qcache == NULL) {
+    return ARES_ENOTFOUND;
+  }
+
+  ares__qcache_expire(channel->qcache, now);
+
+  key = ares__qcache_calc_key(dnsrec);
+  if (key == NULL) {
+    status = ARES_ENOMEM;
+    goto done;
+  }
+
+  entry = ares__htable_strvp_get_direct(channel->qcache->cache, key);
+  if (entry == NULL) {
+    status = ARES_ENOTFOUND;
+    goto done;
+  }
+
+  ares_dns_record_write_ttl_decrement(
+    entry->dnsrec, (unsigned int)(now->tv_sec - entry->insert_ts));
+
+  *dnsrec_resp = entry->dnsrec;
+
+done:
+  ares_free(key);
+  return status;
+}
+
+ares_status_t ares_qcache_insert(ares_channel_t       *channel,
+                                 const struct timeval *now,
+                                 const struct query   *query,
+                                 ares_dns_record_t    *dnsrec)
+{
+  return ares__qcache_insert(channel->qcache, dnsrec, query->qbuf, query->qlen,
+                             now);
+}