dnsproxy: Fix the negative caching of AAAA record

Handle the TCP offset properly.

diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index 03d334f..f309d0d 100644 (file)
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -1283,9 +1283,12 @@ static int cache_update(struct server_data *srv, unsigned char *msg,
         * to cache the negative response.
         */
        if ((err == -ENOMSG || err == -ENOBUFS) &&
-                       reply_query_type(msg, msg_len) == 28) {
+                       reply_query_type(msg + offset,
+                                       msg_len - offset) == 28) {
                entry = g_hash_table_lookup(cache, question);
                if (entry && entry->ipv4 && entry->ipv6 == NULL) {
+                       int cache_offset = 0;
+
                        data = g_try_new(struct cache_data, 1);
                        if (data == NULL)
                                return -ENOMEM;
@@ -1293,11 +1296,17 @@ static int cache_update(struct server_data *srv, unsigned char *msg,
                        data->type = type;
                        data->answers = msg[5];
                        data->timeout = entry->ipv4->timeout;
-                       data->data_len = msg_len;
-                       data->data = ptr = g_malloc(msg_len);
+                       if (srv->protocol == IPPROTO_UDP)
+                               cache_offset = 2;
+                       data->data_len = msg_len + cache_offset;
+                       data->data = ptr = g_malloc(data->data_len);
+                       ptr[0] = (data->data_len - 2) / 256;
+                       ptr[1] = (data->data_len - 2) - ptr[0] * 256;
+                       if (srv->protocol == IPPROTO_UDP)
+                               ptr += 2;
                        data->valid_until = entry->ipv4->valid_until;
                        data->cache_until = entry->ipv4->cache_until;
-                       memcpy(data->data, msg, msg_len);
+                       memcpy(ptr, msg, msg_len);
                        entry->ipv6 = data;
                        /*
                         * we will get a "hit" when we serve the response