Kernel: Print to debug log ICMP unreachable messages

These messages should be forwarded to underlying sockets

kernel/include/kernel/Networking/ICMP.h

@@ -18,6 +18,7 @@ namespace Kernel
 	enum ICMPType : uint8_t
 	{
 		EchoReply = 0x00,
+		DestinationUnreachable = 0x03,
 		EchoRequest = 0x08,
 	};
 

kernel/kernel/Networking/IPv4Layer.cpp

@@ -212,6 +212,13 @@ namespace Kernel
 						TRY(interface.send_bytes(dst_mac, EtherType::IPv4, packet));
 						break;
 					}
+					case ICMPType::DestinationUnreachable:
+					{
+						auto& ipv4_header = ipv4_data.slice(sizeof(ICMPHeader)).as<const IPv4Header>();
+						dprintln("Destination '{}' unreachable, code {2H}", ipv4_header.dst_address, icmp_header.code);
+						// FIXME: inform the socket
+						break;
+					}
 					default:
 						dprintln("Unhandleded ICMP packet (type {2H})", icmp_header.type);
 						break;