1#ifndef __6LOWPAN_NHC_H
2#define __6LOWPAN_NHC_H
3
4#include <linux/skbuff.h>
5#include <linux/rbtree.h>
6#include <linux/module.h>
7
8#include <net/6lowpan.h>
9#include <net/ipv6.h>
10
11#define LOWPAN_NHC_MAX_ID_LEN	1
12
13/**
14 * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
15 *
16 * @__nhc: variable name of the lowpan_nhc struct.
17 * @_name: const char * of common header compression name.
18 * @_nexthdr: ipv6 nexthdr field for the header compression.
19 * @_nexthdrlen: ipv6 nexthdr len for the reserved space.
20 * @_idsetup: callback to setup id and mask values.
21 * @_idlen: len for the next header id and mask, should be always the same.
22 * @_uncompress: callback for uncompression call.
23 * @_compress: callback for compression call.
24 */
25#define LOWPAN_NHC(__nhc, _name, _nexthdr,	\
26		   _hdrlen, _idsetup, _idlen,	\
27		   _uncompress, _compress)	\
28static u8 __nhc##_val[_idlen];			\
29static u8 __nhc##_mask[_idlen];			\
30static struct lowpan_nhc __nhc = {		\
31	.name		= _name,		\
32	.nexthdr	= _nexthdr,		\
33	.nexthdrlen	= _hdrlen,		\
34	.id		= __nhc##_val,		\
35	.idmask		= __nhc##_mask,		\
36	.idlen		= _idlen,		\
37	.idsetup	= _idsetup,		\
38	.uncompress	= _uncompress,		\
39	.compress	= _compress,		\
40}
41
42#define module_lowpan_nhc(__nhc)		\
43static int __init __nhc##_init(void)		\
44{						\
45	return lowpan_nhc_add(&(__nhc));	\
46}						\
47module_init(__nhc##_init);			\
48static void __exit __nhc##_exit(void)		\
49{						\
50	lowpan_nhc_del(&(__nhc));		\
51}						\
52module_exit(__nhc##_exit);
53
54/**
55 * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
56 *
57 * @node: holder for the rbtree.
58 * @name: name of the specific next header compression
59 * @nexthdr: next header value of the protocol which should be compressed.
60 * @nexthdrlen: ipv6 nexthdr len for the reserved space.
61 * @id: array for nhc id. Note this need to be in network byteorder.
62 * @mask: array for nhc id mask. Note this need to be in network byteorder.
63 * @len: the length of the next header id and mask.
64 * @setup: callback to setup fill the next header id value and mask.
65 * @compress: callback to do the header compression.
66 * @uncompress: callback to do the header uncompression.
67 */
68struct lowpan_nhc {
69	struct rb_node	node;
70	const char	*name;
71	const u8	nexthdr;
72	const size_t	nexthdrlen;
73	u8		*id;
74	u8		*idmask;
75	const size_t	idlen;
76
77	void		(*idsetup)(struct lowpan_nhc *nhc);
78	int		(*uncompress)(struct sk_buff *skb, size_t needed);
79	int		(*compress)(struct sk_buff *skb, u8 **hc_ptr);
80};
81
82/**
83 * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
84 *
85 * @nexthdr: ipv6 nexthdr value.
86 */
87struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
88
89/**
90 * lowpan_nhc_check_compression - checks if we support compression format. If
91 *	we support the nhc by nexthdr field, the 6LoWPAN iphc NHC bit will be
92 *	set. If we don't support nexthdr will be added as inline data to the
93 *	6LoWPAN header.
94 *
95 * @skb: skb of 6LoWPAN header to read nhc and replace header.
96 * @hdr: ipv6hdr to check the nexthdr value
97 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
98 *	    replaced header.
99 * @iphc0: iphc0 pointer to set the 6LoWPAN NHC bit
100 */
101int lowpan_nhc_check_compression(struct sk_buff *skb,
102				 const struct ipv6hdr *hdr, u8 **hc_ptr,
103				 u8 *iphc0);
104
105/**
106 * lowpan_nhc_do_compression - calling compress callback for nhc
107 *
108 * @skb: skb of 6LoWPAN header to read nhc and replace header.
109 * @hdr: ipv6hdr to set the nexthdr value
110 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
111 *	    replaced header.
112 */
113int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
114			      u8 **hc_ptr);
115
116/**
117 * lowpan_nhc_do_uncompression - calling uncompress callback for nhc
118 *
119 * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
120 * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
121 * @dev: netdevice for print logging information.
122 * @hdr: ipv6hdr for setting nexthdr value.
123 */
124int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct net_device *dev,
125				struct ipv6hdr *hdr);
126
127/**
128 * lowpan_nhc_add - register a next header compression to framework
129 *
130 * @nhc: nhc which should be add.
131 */
132int lowpan_nhc_add(struct lowpan_nhc *nhc);
133
134/**
135 * lowpan_nhc_del - delete a next header compression from framework
136 *
137 * @nhc: nhc which should be delete.
138 */
139void lowpan_nhc_del(struct lowpan_nhc *nhc);
140
141/**
142 * lowpan_nhc_init - adding all default nhcs
143 */
144void lowpan_nhc_init(void);
145
146#endif /* __6LOWPAN_NHC_H */
147