Kernel: Add netmask and gateway to NetworkAdapter

Author: https://github.com/deoxxa
Commit: 1aa7437ad7
Pull-request: https://github.com/SerenityOS/serenity/pull/499
Reviewed-by: https://github.com/awesomekling

Kernel/Net/NetworkAdapter.cpp

@@ -103,6 +103,16 @@ void NetworkAdapter::set_ipv4_address(const IPv4Address& address)
     m_ipv4_address = address;
 }
 
+void NetworkAdapter::set_ipv4_netmask(const IPv4Address& netmask)
+{
+    m_ipv4_netmask = netmask;
+}
+
+void NetworkAdapter::set_ipv4_gateway(const IPv4Address& gateway)
+{
+    m_ipv4_gateway = gateway;
+}
+
 void NetworkAdapter::set_interface_name(const StringView& basename)
 {
     // FIXME: Find a unique name for this interface, starting with $basename.