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Alexander Aring92aa7c62015-01-09 16:42:57 +01001#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 */