Define protocol_offset() for DNS transport layer offset

diff --git a/plugins/dnsproxy.c b/plugins/dnsproxy.c
index ac18490..ca58df5 100644 (file)
--- a/plugins/dnsproxy.c
+++ b/plugins/dnsproxy.c
@@ -116,6 +116,21 @@ static guint udp_listener_watch = 0;
 static GIOChannel *tcp_listener_channel = NULL;
 static guint tcp_listener_watch = 0;
 
+static int protocol_offset(int protocol)
+{
+       switch (protocol) {
+       case IPPROTO_UDP:
+               return 0;
+
+       case IPPROTO_TCP:
+               return 2;
+
+       default:
+               return -EINVAL;
+       }
+
+}
+
 static struct request_data *find_request(guint16 id)
 {
        GSList *list;
@@ -167,22 +182,12 @@ static void send_response(int sk, unsigned char *buf, int len,
                                int protocol)
 {
        struct domain_hdr *hdr;
-       int err, offset;
+       int err, offset = protocol_offset(protocol);
 
        DBG("");
 
-       switch (protocol) {
-       case IPPROTO_UDP:
-               offset = 0;
-               break;
-
-       case IPPROTO_TCP:
-               offset = 2;
-               break;
-
-       default:
+       if (offset < 0)
                return;
-       }
 
        if (len < 12)
                return;
@@ -350,21 +355,10 @@ static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol)
 {
        struct domain_hdr *hdr;
        struct request_data *req;
-       unsigned char offset;
-       int dns_id, sk, err;
+       int dns_id, sk, err, offset = protocol_offset(protocol);
 
-       switch (protocol) {
-       case IPPROTO_UDP:
-               offset = 0;
-               break;
-
-       case IPPROTO_TCP:
-               offset = 2;
-               break;
-
-       default:
-               return -EINVAL;
-       }
+       if (offset < 0)
+               return offset;
 
        hdr = (void *)(reply + offset);
        dns_id = reply[offset] | reply[offset + 1] << 8;