6lowpan: add nhc module for GHC hop-by-hopextension header detection

Acked-by: Jukka Rissanen <[e-mail]>
Signed-off-by: Stefan Schmidt <[e-mail]>
Signed-off-by: Alexander Aring <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

net/6lowpan/Kconfig

···
 	---help---
 	  6LoWPAN IPv6 UDP Header compression according to RFC6282.
 
+config 6LOWPAN_GHC_EXT_HDR_HOP
+	tristate "GHC Hop-by-Hop Options Header Support"
+	---help---
+	  6LoWPAN IPv6 Hop-by-Hop option generic header compression according
+	  to RFC7400.
+
 endif

net/6lowpan/Makefile

···
 obj-$(CONFIG_6LOWPAN_NHC_MOBILITY) += nhc_mobility.o
 obj-$(CONFIG_6LOWPAN_NHC_ROUTING) += nhc_routing.o
 obj-$(CONFIG_6LOWPAN_NHC_UDP) += nhc_udp.o
+
+#rfc7400 ghcs
+obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_HOP) += nhc_ghc_ext_hop.o

net/6lowpan/nhc_ghc_ext_hop.c

···
+/*
+ *	6LoWPAN Extension Header compression according to RFC7400
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include "nhc.h"
+
+#define LOWPAN_GHC_EXT_HOP_IDLEN	1
+#define LOWPAN_GHC_EXT_HOP_ID_0		0xb0
+#define LOWPAN_GHC_EXT_HOP_MASK_0	0xfe
+
+static void hop_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_EXT_HOP_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_EXT_HOP_MASK_0;
+}
+
+LOWPAN_NHC(ghc_ext_hop, "RFC7400 Hop-by-Hop Extension Header", NEXTHDR_HOP, 0,
+	   hop_ghid_setup, LOWPAN_GHC_EXT_HOP_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_ext_hop);
+MODULE_DESCRIPTION("6LoWPAN generic header hop-by-hop extension compression");
+MODULE_LICENSE("GPL");