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 * @_idsetup: callback to setup id and mask values.
20 * @_idlen: len for the next header id and mask, should be always the same.
21 * @_uncompress: callback for uncompression call.
22 * @_compress: callback for compression call.
23 */
24 #define LOWPAN_NHC(__nhc, _name, _nexthdr, \
25 _hdrlen, _idsetup, _idlen, \
26 _uncompress, _compress) \
27 static u8 __nhc##_val[_idlen]; \
28 static u8 __nhc##_mask[_idlen]; \
29 static struct lowpan_nhc __nhc = { \
30 .name = _name, \
31 .nexthdr = _nexthdr, \
32 .nexthdrlen = _hdrlen, \
33 .id = __nhc##_val, \
34 .idmask = __nhc##_mask, \
35 .idlen = _idlen, \
36 .idsetup = _idsetup, \
37 .uncompress = _uncompress, \
38 .compress = _compress, \
39 }
40
41 #define module_lowpan_nhc(__nhc) \
42 static int __init __nhc##_init(void) \
43 { \
44 return lowpan_nhc_add(&(__nhc)); \
45 } \
46 module_init(__nhc##_init); \
47 static void __exit __nhc##_exit(void) \
48 { \
49 lowpan_nhc_del(&(__nhc)); \
50 } \
51 module_exit(__nhc##_exit);
52
53 /**
54 * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
55 *
56 * @node: holder for the rbtree.
57 * @name: name of the specific next header compression
58 * @nexthdr: next header value of the protocol which should be compressed.
59 * @nexthdrlen: ipv6 nexthdr len for the reserved space.
60 * @id: array for nhc id. Note this need to be in network byteorder.
61 * @mask: array for nhc id mask. Note this need to be in network byteorder.
62 * @len: the length of the next header id and mask.
63 * @setup: callback to setup fill the next header id value and mask.
64 * @compress: callback to do the header compression.
65 * @uncompress: callback to do the header uncompression.
66 */
67 struct lowpan_nhc {
68 struct rb_node node;
69 const char *name;
70 const u8 nexthdr;
71 const size_t nexthdrlen;
72 u8 *id;
73 u8 *idmask;
74 const size_t idlen;
75
76 void (*idsetup)(struct lowpan_nhc *nhc);
77 int (*uncompress)(struct sk_buff *skb, size_t needed);
78 int (*compress)(struct sk_buff *skb, u8 **hc_ptr);
79 };
80
81 /**
82 * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
83 *
84 * @nexthdr: ipv6 nexthdr value.
85 */
86 struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
87
88 /**
89 * lowpan_nhc_check_compression - checks if we support compression format. If
90 * we support the nhc by nexthdr field, the function will return 0. If we
91 * don't support the nhc by nexthdr this function will return -ENOENT.
92 *
93 * @skb: skb of 6LoWPAN header to read nhc and replace header.
94 * @hdr: ipv6hdr to check the nexthdr value
95 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
96 * replaced header.
97 */
98 int lowpan_nhc_check_compression(struct sk_buff *skb,
99 const struct ipv6hdr *hdr, u8 **hc_ptr);
100
101 /**
102 * lowpan_nhc_do_compression - calling compress callback for nhc
103 *
104 * @skb: skb of 6LoWPAN header to read nhc and replace header.
105 * @hdr: ipv6hdr to set the nexthdr value
106 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
107 * replaced header.
108 */
109 int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
110 u8 **hc_ptr);
111
112 /**
113 * lowpan_nhc_do_uncompression - calling uncompress callback for nhc
114 *
115 * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
116 * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
117 * @dev: netdevice for print logging information.
118 * @hdr: ipv6hdr for setting nexthdr value.
119 */
120 int lowpan_nhc_do_uncompression(struct sk_buff *skb,
121 const struct net_device *dev,
122 struct ipv6hdr *hdr);
123
124 /**
125 * lowpan_nhc_add - register a next header compression to framework
126 *
127 * @nhc: nhc which should be add.
128 */
129 int lowpan_nhc_add(struct lowpan_nhc *nhc);
130
131 /**
132 * lowpan_nhc_del - delete a next header compression from framework
133 *
134 * @nhc: nhc which should be delete.
135 */
136 void lowpan_nhc_del(struct lowpan_nhc *nhc);
137
138 /**
139 * lowpan_nhc_init - adding all default nhcs
140 */
141 void lowpan_nhc_init(void);
142
143 #endif /* __6LOWPAN_NHC_H */