include: Expose LwIP's RAW protocol

This commit optionalizes LwIP's "RAW" protocol, making it available to
use within Unikraft when enabled.

Signed-off-by: Ethan Cotterell <e.cotterell@lancs.ac.uk>
Signed-off-by: Alexander Jung <a.jung@lancs.ac.uk>

Config.uk

@@ -170,6 +170,13 @@ config LWIP_UDP
 	bool "UDP support"
 	default y
 
+menuconfig LWIP_RAW
+	bool "RAW support"
+	default n
+	help
+		Enable the RAW address family (AF_RAW).  This option enables an
+		application to be able to hook into the IP layer itself.
+
 menuconfig LWIP_TCP
 	bool "TCP support"
 	default y

include/lwipopts.h

@@ -120,6 +120,15 @@ void sys_free(void *ptr);
 #define IP_REASS_MAX_PBUFS CONFIG_LWIP_IP_REASS_MAX_PBUFS
 #endif
 
+/**
+ * RAW support
+ */
+#if CONFIG_LWIP_RAW
+#define LWIP_RAW 1
+#else
+#define LWIP_RAW 0
+#endif
+
 /**
  * UDP options
  */