nathelper(k): new test 128 to check port in contact against source port

- used for nat_uac_test()
- imported from ser flavour

modules_k/nathelper/README

@@ -503,6 +503,9 @@ fix_nated_register();
      * 32 - test if the source IP address of signaling is a RFC1918
        address
      * 64 - test if the source connection of signaling is a WebSocket
+     * 128 - test if the Contact URI port differs from the source port of
+       the request (Warning: this is might be legal or even intended
+       combination in non natted scenarios)
 
    All flags can be bitwise combined, the test returns true if any of the
    tests identified a NAT.

modules_k/nathelper/doc/nathelper_admin.xml

@@ -570,6 +570,11 @@ fix_nated_register();
 			<emphasis>64</emphasis> -  test if the source connection of
 			signaling is a WebSocket
 			</para></listitem>
+			<listitem><para>
+			<emphasis>128</emphasis> -  test if the Contact URI port differs
+			from the source port of the request (Warning: this is might be legal
+			or even intended combination in non natted scenarios)
+			</para></listitem>
 			</itemizedlist>
 		<para>
 		All flags can be bitwise combined, the test returns true if any of 

modules_k/nathelper/nathelper.c

@@ -244,6 +244,7 @@ MODULE_VERSION
 #define	NAT_UAC_TEST_RPORT	0x10
 #define	NAT_UAC_TEST_O_1918	0x20
 #define NAT_UAC_TEST_WS		0x40
+#define	NAT_UAC_TEST_C_PORT	0x80
 
 
 #define DEFAULT_RTPP_SET_ID		0
@@ -1396,6 +1397,27 @@ contact_1918(struct sip_msg* msg)
 	return (is1918addr(&(uri.host)) == 1) ? 1 : 0;
 }
 
+/*
+ * test if source port of signaling is different from
+ * port advertised in Contact
+ */
+static int
+contact_rport(struct sip_msg* msg)
+{
+	struct sip_uri uri;
+	contact_t* c;
+
+	if (get_contact_uri(msg, &uri, &c) == -1) {
+		return -1;
+	}
+
+	if (msg->rcv.src_port != (uri.port_no ? uri.port_no : SIP_PORT)) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
 /*
  * test for occurrence of RFC1918 IP address in SDP
  */
@@ -1496,12 +1518,19 @@ nat_uac_test_f(struct sip_msg* msg, char* str1, char* str2)
 		return 1;
 
 	/*
- 	 * tests prototype to check whether the message arrived on a WebSocket
+	 * test prototype to check whether the message arrived on a WebSocket
  	 */
 	if ((tests & NAT_UAC_TEST_WS)
 		&& (msg->rcv.proto == PROTO_WS || msg->rcv.proto == PROTO_WSS))
 		return 1;
 
+	/*
+	 * test if source port of signaling is different from
+	 * port advertised in Contact
+	 */
+	if ((tests & NAT_UAC_TEST_C_PORT) && (contact_rport(msg) > 0))
+		return 1;
+
 	/* no test succeeded */
 	return -1;