dnsproxy: Check cache properly for TCP packets

The DNS packet starts from offset 2 in TCP payload.

diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index f309d0d..d5c77f7 100644 (file)
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -665,13 +665,22 @@ static uint16_t cache_check_validity(char *question, uint16_t type,
        return type;
 }
 
-static struct cache_entry *cache_check(gpointer request, int *qtype)
+static struct cache_entry *cache_check(gpointer request, int *qtype, int proto)
 {
-       char *question = request + 12;
+       char *question;
        struct cache_entry *entry;
        struct domain_question *q;
        uint16_t type;
-       int offset;
+       int offset, proto_offset;
+
+       if (request == NULL)
+               return NULL;
+
+       proto_offset = protocol_offset(proto);
+       if (proto_offset < 0)
+               return NULL;
+
+       question = request + proto_offset + 12;
 
        offset = strlen(question) + 1;
        q = (void *) (question + offset);
@@ -1457,7 +1466,7 @@ static int ns_resolv(struct server_data *server, struct request_data *req,
        char *dot, *lookup = (char *) name;
        struct cache_entry *entry;
 
-       entry = cache_check(request, &type);
+       entry = cache_check(request, &type, req->protocol);
        if (entry != NULL) {
                int ttl_left = 0;
                struct cache_data *data;