drivers: net: loopback: Allow tests to control address swapping

Some of the network tests require that source and destination
addresses are not swapped so allow test to control the address
swapping from the test.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

drivers/net/loopback.c

@@ -25,6 +25,16 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 
 #include <zephyr/net/dummy.h>
 
+/* Allow network tests to control the IP addresses swapping */
+#if defined(CONFIG_NET_TEST)
+static bool loopback_dont_swap_addresses;
+
+void loopback_enable_address_swap(bool swap_addresses)
+{
+	loopback_dont_swap_addresses = !swap_addresses;
+}
+#endif /* CONFIG_NET_TEST */
+
 int loopback_dev_init(const struct device *dev)
 {
 	ARG_UNUSED(dev);
@@ -123,17 +133,22 @@ static int loopback_send(const struct device *dev, struct net_pkt *pkt)
 
 	/* We need to swap the IP addresses because otherwise
 	 * the packet will be dropped.
+	 *
+	 * Some of the network tests require that addresses are not swapped so allow
+	 * the test to control this remotely.
 	 */
-	if (net_pkt_family(pkt) == AF_INET6) {
-		net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->src,
-				       NET_IPV6_HDR(pkt)->dst);
-		net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->dst,
-				       NET_IPV6_HDR(pkt)->src);
-	} else {
-		net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->src,
-				       NET_IPV4_HDR(pkt)->dst);
-		net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->dst,
-				       NET_IPV4_HDR(pkt)->src);
+	if (!COND_CODE_1(CONFIG_NET_TEST, (loopback_dont_swap_addresses), (false))) {
+		if (net_pkt_family(pkt) == AF_INET6) {
+			net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->src,
+					       NET_IPV6_HDR(pkt)->dst);
+			net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->dst,
+					       NET_IPV6_HDR(pkt)->src);
+		} else {
+			net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->src,
+					       NET_IPV4_HDR(pkt)->dst);
+			net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->dst,
+					       NET_IPV4_HDR(pkt)->src);
+		}
 	}
 
 	res = net_recv_data(net_pkt_iface(cloned), cloned);

subsys/net/ip/net_private.h

@@ -142,6 +142,10 @@ extern void mdns_init_responder(void);
 static inline void mdns_init_responder(void) { }
 #endif /* CONFIG_MDNS_RESPONDER */
 
+#if defined(CONFIG_NET_TEST)
+extern void loopback_enable_address_swap(bool swap_addresses);
+#endif /* CONFIG_NET_TEST */
+
 #if defined(CONFIG_NET_NATIVE)
 enum net_verdict net_ipv4_input(struct net_pkt *pkt, bool is_loopback);
 enum net_verdict net_ipv6_input(struct net_pkt *pkt, bool is_loopback);