nhc.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __6LOWPAN_NHC_H
  3#define __6LOWPAN_NHC_H
  4
  5#include <linux/skbuff.h>
  6#include <linux/rbtree.h>
  7#include <linux/module.h>
  8
  9#include <net/6lowpan.h>
 10#include <net/ipv6.h>
 11
 12/**
 13 * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
 14 *
 15 * @__nhc: variable name of the lowpan_nhc struct.
 16 * @_name: const char * of common header compression name.
 17 * @_nexthdr: ipv6 nexthdr field for the header compression.
 18 * @_nexthdrlen: ipv6 nexthdr len for the reserved space.
 19 * @_id: one byte nhc id value.
 20 * @_idmask: one byte nhc id mask value.
 21 * @_uncompress: callback for uncompression call.
 22 * @_compress: callback for compression call.
 23 */
 24#define LOWPAN_NHC(__nhc, _name, _nexthdr,	\
 25		   _hdrlen, _id, _idmask,	\
 26		   _uncompress, _compress)	\
 27static const struct lowpan_nhc __nhc = {	\
 28	.name		= _name,		\
 29	.nexthdr	= _nexthdr,		\
 30	.nexthdrlen	= _hdrlen,		\
 31	.id		= _id,			\
 32	.idmask		= _idmask,		\
 33	.uncompress	= _uncompress,		\
 34	.compress	= _compress,		\
 35}
 36
 37#define module_lowpan_nhc(__nhc)		\
 38static int __init __nhc##_init(void)		\
 39{						\
 40	return lowpan_nhc_add(&(__nhc));	\
 41}						\
 42module_init(__nhc##_init);			\
 43static void __exit __nhc##_exit(void)		\
 44{						\
 45	lowpan_nhc_del(&(__nhc));		\
 46}						\
 47module_exit(__nhc##_exit);
 48
 49/**
 50 * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
 51 *
 52 * @name: name of the specific next header compression
 53 * @nexthdr: next header value of the protocol which should be compressed.
 54 * @nexthdrlen: ipv6 nexthdr len for the reserved space.
 55 * @id: one byte nhc id value.
 56 * @idmask: one byte nhc id mask value.
 57 * @compress: callback to do the header compression.
 58 * @uncompress: callback to do the header uncompression.
 59 */
 60struct lowpan_nhc {
 61	const char	*name;
 62	u8		nexthdr;
 63	size_t		nexthdrlen;
 64	u8		id;
 65	u8		idmask;
 66
 67	int		(*uncompress)(struct sk_buff *skb, size_t needed);
 68	int		(*compress)(struct sk_buff *skb, u8 **hc_ptr);
 69};
 70
 71/**
 72 * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
 73 *
 74 * @nexthdr: ipv6 nexthdr value.
 75 */
 76struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
 77
 78/**
 79 * lowpan_nhc_check_compression - checks if we support compression format. If
 80 *	we support the nhc by nexthdr field, the function will return 0. If we
 81 *	don't support the nhc by nexthdr this function will return -ENOENT.
 82 *
 83 * @skb: skb of 6LoWPAN header to read nhc and replace header.
 84 * @hdr: ipv6hdr to check the nexthdr value
 85 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
 86 *	    replaced header.
 87 */
 88int lowpan_nhc_check_compression(struct sk_buff *skb,
 89				 const struct ipv6hdr *hdr, u8 **hc_ptr);
 90
 91/**
 92 * lowpan_nhc_do_compression - calling compress callback for nhc
 93 *
 94 * @skb: skb of 6LoWPAN header to read nhc and replace header.
 95 * @hdr: ipv6hdr to set the nexthdr value
 96 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
 97 *	    replaced header.
 98 */
 99int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
100			      u8 **hc_ptr);
101
102/**
103 * lowpan_nhc_do_uncompression - calling uncompress callback for nhc
104 *
105 * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
106 * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
107 * @dev: netdevice for print logging information.
108 * @hdr: ipv6hdr for setting nexthdr value.
109 */
110int lowpan_nhc_do_uncompression(struct sk_buff *skb,
111				const struct net_device *dev,
112				struct ipv6hdr *hdr);
113
114/**
115 * lowpan_nhc_add - register a next header compression to framework
116 *
117 * @nhc: nhc which should be add.
118 */
119int lowpan_nhc_add(const struct lowpan_nhc *nhc);
120
121/**
122 * lowpan_nhc_del - delete a next header compression from framework
123 *
124 * @nhc: nhc which should be delete.
125 */
126void lowpan_nhc_del(const struct lowpan_nhc *nhc);
127
128/**
129 * lowpan_nhc_init - adding all default nhcs
130 */
131void lowpan_nhc_init(void);
132
133#endif /* __6LOWPAN_NHC_H */