dnsproxy: Create cache if it is missing when doing lookup

diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index 04b4c79..8366fa4 100644 (file)
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -701,6 +701,51 @@ static uint16_t cache_check_validity(char *question, uint16_t type,
        return type;
 }
 
+static void cache_element_destroy(gpointer value)
+{
+       struct cache_entry *entry = value;
+
+       if (entry == NULL)
+               return;
+
+       if (entry->ipv4 != NULL) {
+               g_free(entry->ipv4->data);
+               g_free(entry->ipv4);
+       }
+
+       if (entry->ipv6 != NULL) {
+               g_free(entry->ipv6->data);
+               g_free(entry->ipv6);
+       }
+
+       g_free(entry->key);
+       g_free(entry);
+
+       if (--cache_size < 0)
+               cache_size = 0;
+}
+
+static gboolean try_remove_cache(gpointer user_data)
+{
+       if (__sync_fetch_and_sub(&cache_refcount, 1) == 1) {
+               DBG("No cache users, removing it.");
+
+               g_hash_table_destroy(cache);
+               cache = NULL;
+       }
+
+       return FALSE;
+}
+
+static void create_cache()
+{
+       if (__sync_fetch_and_add(&cache_refcount, 1) == 0)
+               cache = g_hash_table_new_full(g_str_hash,
+                                       g_str_equal,
+                                       NULL,
+                                       cache_element_destroy);
+}
+
 static struct cache_entry *cache_check(gpointer request, int *qtype, int proto)
 {
        char *question;
@@ -726,6 +771,11 @@ static struct cache_entry *cache_check(gpointer request, int *qtype, int proto)
        if (type != 1 && type != 28)
                return NULL;
 
+       if (cache == NULL) {
+               create_cache();
+               return NULL;
+       }
+
        entry = g_hash_table_lookup(cache, question);
        if (entry == NULL)
                return NULL;
@@ -1332,7 +1382,11 @@ static int cache_update(struct server_data *srv, unsigned char *msg,
        if ((err == -ENOMSG || err == -ENOBUFS) &&
                        reply_query_type(msg + offset,
                                        msg_len - offset) == 28) {
-               entry = g_hash_table_lookup(cache, question);
+               if (cache == NULL) {
+                       create_cache();
+                       entry = NULL;
+               } else
+                       entry = g_hash_table_lookup(cache, question);
                if (entry && entry->ipv4 && entry->ipv6 == NULL) {
                        int cache_offset = 0;
 
@@ -1733,42 +1787,6 @@ static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol,
        return err;
 }
 
-static void cache_element_destroy(gpointer value)
-{
-       struct cache_entry *entry = value;
-
-       if (entry == NULL)
-               return;
-
-       if (entry->ipv4 != NULL) {
-               g_free(entry->ipv4->data);
-               g_free(entry->ipv4);
-       }
-
-       if (entry->ipv6 != NULL) {
-               g_free(entry->ipv6->data);
-               g_free(entry->ipv6);
-       }
-
-       g_free(entry->key);
-       g_free(entry);
-
-       if (--cache_size < 0)
-               cache_size = 0;
-}
-
-static gboolean try_remove_cache(gpointer user_data)
-{
-       if (__sync_fetch_and_sub(&cache_refcount, 1) == 1) {
-               DBG("No cache users, removing it.");
-
-               g_hash_table_destroy(cache);
-               cache = NULL;
-       }
-
-       return FALSE;
-}
-
 static void server_destroy_socket(struct server_data *data)
 {
        DBG("index %d server %s proto %d", data->index,
@@ -2138,11 +2156,7 @@ static int server_create_socket(struct server_data *data)
                }
        }
 
-       if (__sync_fetch_and_add(&cache_refcount, 1) == 0)
-               cache = g_hash_table_new_full(g_str_hash,
-                                       g_str_equal,
-                                       NULL,
-                                       cache_element_destroy);
+       create_cache();
 
        return 0;
 }