net: if: Add userspace support to IPv4 netmask set function

Allow application to call net_if_ipv4_set_netmask_by_index()
and set the netmask if enabled by configuration.

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

Author: jukkar

include/net/net_if.h

@@ -1652,21 +1652,19 @@ struct in_addr *net_if_ipv4_get_global_addr(struct net_if *iface,
  * @param iface Interface to use.
  * @param netmask IPv4 netmask
  */
-static inline void net_if_ipv4_set_netmask(struct net_if *iface,
-					   const struct in_addr *netmask)
-{
-#if defined(CONFIG_NET_IPV4)
-	if (net_if_config_ipv4_get(iface, NULL) < 0) {
-		return;
-	}
-
-	if (!iface->config.ip.ipv4) {
-		return;
-	}
+void net_if_ipv4_set_netmask(struct net_if *iface,
+			     const struct in_addr *netmask);
 
-	net_ipaddr_copy(&iface->config.ip.ipv4->netmask, netmask);
-#endif
-}
+/**
+ * @brief Set IPv4 netmask for an interface index.
+ *
+ * @param index Network interface index
+ * @param netmask IPv4 netmask
+ *
+ * @return True if netmask was added, false otherwise.
+ */
+__syscall bool net_if_ipv4_set_netmask_by_index(int index,
+						const struct in_addr *netmask);
 
 /**
  * @brief Set IPv4 gateway for an interface.

subsys/net/ip/net_if.c

@@ -2597,6 +2597,53 @@ Z_SYSCALL_HANDLER(net_if_ipv4_addr_lookup_by_index, addr)
 }
 #endif
 
+void net_if_ipv4_set_netmask(struct net_if *iface,
+			     const struct in_addr *netmask)
+{
+#if defined(CONFIG_NET_IPV4)
+	if (net_if_config_ipv4_get(iface, NULL) < 0) {
+		return;
+	}
+
+	if (!iface->config.ip.ipv4) {
+		return;
+	}
+
+	net_ipaddr_copy(&iface->config.ip.ipv4->netmask, netmask);
+#endif
+}
+
+bool z_impl_net_if_ipv4_set_netmask_by_index(int index,
+					     const struct in_addr *netmask)
+{
+	struct net_if *iface;
+
+	iface = net_if_get_by_index(index);
+	if (!iface) {
+		return false;
+	}
+
+	net_if_ipv4_set_netmask(iface, netmask);
+
+	return true;
+}
+
+#ifdef CONFIG_USERSPACE
+Z_SYSCALL_HANDLER(net_if_ipv4_set_netmask_by_index, index, netmask)
+{
+#if defined(CONFIG_NET_IF_USERSPACE_ACCESS)
+	struct in_addr netmask_addr;
+
+	Z_OOPS(z_user_from_copy(&netmask_addr, (void *)netmask,
+				sizeof(netmask_addr)));
+
+	return z_impl_net_if_ipv4_set_netmask_by_index(index, &netmask_addr);
+#else
+	return false;
+#endif
+}
+#endif /* CONFIG_USERSPACE */
+
 #if defined(CONFIG_NET_IPV4)
 static struct net_if_addr *ipv4_addr_find(struct net_if *iface,
 					  struct in_addr *addr)

tests/net/iface/src/main.c

@@ -779,6 +779,17 @@ static void v6_addr_rm_user(void)
 	}
 }
 
+static void netmask_addr_add(void)
+{
+	struct in_addr my_netmask = { { { 255, 255, 255, 0 } } };
+	bool ret;
+
+	if (IS_ENABLED(CONFIG_NET_IF_USERSPACE_ACCESS)) {
+		ret = net_if_ipv4_set_netmask_by_index(1, &my_netmask);
+		zassert_true(ret, "Cannot add IPv4 netmask");
+	}
+}
+
 void test_main(void)
 {
 	ztest_test_suite(net_iface_test,
@@ -806,7 +817,9 @@ void test_main(void)
 			 ztest_unit_test(v6_addr_rm),
 			 ztest_user_unit_test(v6_addr_add_user),
 			 ztest_user_unit_test(v6_addr_lookup_user),
-			 ztest_user_unit_test(v6_addr_rm_user)
+			 ztest_user_unit_test(v6_addr_rm_user),
+			 ztest_unit_test(netmask_addr_add),
+			 ztest_user_unit_test(netmask_addr_add)
 		);
 
 	ztest_run_test_suite(net_iface_test);