LXR linux/net/6lowpan/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 * @_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)      \
  27static u8 __nhc##_val[_idlen];                  \
  28static u8 __nhc##_mask[_idlen];                 \
  29static 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)                \
  42static int __init __nhc##_init(void)            \
  43{                                               \
  44        return lowpan_nhc_add(&(__nhc));        \
  45}                                               \
  46module_init(__nhc##_init);                      \
  47static void __exit __nhc##_exit(void)           \
  48{                                               \
  49        lowpan_nhc_del(&(__nhc));               \
  50}                                               \
  51module_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 */
  67struct 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 */
  86struct 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 */
  98int 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 */
 109int 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 */
 120int 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 */
 129int 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 */
 136void lowpan_nhc_del(struct lowpan_nhc *nhc);
 137
 138/**
 139 * lowpan_nhc_init - adding all default nhcs
 140 */
 141void lowpan_nhc_init(void);
 142
 143#endif /* __6LOWPAN_NHC_H */
 144