6lowpan: add nhc module for GHC ICMPv6 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 generic header compression according to RFC7400.
 
+config 6LOWPAN_GHC_ICMPV6
+	tristate "GHC ICMPv6 Support"
+	---help---
+	  6LoWPAN IPv6 ICMPv6 generic header compression according to RFC7400.
+
 endif

net/6lowpan/Makefile

···
 #rfc7400 ghcs
 obj-$(CONFIG_6LOWPAN_GHC_EXT_HDR_HOP) += nhc_ghc_ext_hop.o
 obj-$(CONFIG_6LOWPAN_GHC_UDP) += nhc_ghc_udp.o
+obj-$(CONFIG_6LOWPAN_GHC_ICMPV6) += nhc_ghc_icmpv6.o

net/6lowpan/nhc_ghc_icmpv6.c

···
+/*
+ *	6LoWPAN ICMPv6 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_ICMPV6_IDLEN		1
+#define LOWPAN_GHC_ICMPV6_ID_0		0xdf
+#define LOWPAN_GHC_ICMPV6_MASK_0	0xff
+
+static void icmpv6_ghid_setup(struct lowpan_nhc *nhc)
+{
+	nhc->id[0] = LOWPAN_GHC_ICMPV6_ID_0;
+	nhc->idmask[0] = LOWPAN_GHC_ICMPV6_MASK_0;
+}
+
+LOWPAN_NHC(ghc_icmpv6, "RFC7400 ICMPv6", NEXTHDR_ICMP, 0,
+	   icmpv6_ghid_setup, LOWPAN_GHC_ICMPV6_IDLEN, NULL, NULL);
+
+module_lowpan_nhc(ghc_icmpv6);
+MODULE_DESCRIPTION("6LoWPAN generic header ICMPv6 compression");
+MODULE_LICENSE("GPL");