LXR linux/net/6lowpan/nhc.h

   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/**
  12 * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
  13 *
  14 * @__nhc: variable name of the lowpan_nhc struct.
  15 * @_name: const char * of common header compression name.
  16 * @_nexthdr: ipv6 nexthdr field for the header compression.
  17 * @_nexthdrlen: ipv6 nexthdr len for the reserved space.
  18 * @_idsetup: callback to setup id and mask values.
  19 * @_idlen: len for the next header id and mask, should be always the same.
  20 * @_uncompress: callback for uncompression call.
  21 * @_compress: callback for compression call.
  22 */
  23#define LOWPAN_NHC(__nhc, _name, _nexthdr,      \
  24                   _hdrlen, _idsetup, _idlen,   \
  25                   _uncompress, _compress)      \
  26static u8 __nhc##_val[_idlen];                  \
  27static u8 __nhc##_mask[_idlen];                 \
  28static struct lowpan_nhc __nhc = {              \
  29        .name           = _name,                \
  30        .nexthdr        = _nexthdr,             \
  31        .nexthdrlen     = _hdrlen,              \
  32        .id             = __nhc##_val,          \
  33        .idmask         = __nhc##_mask,         \
  34        .idlen          = _idlen,               \
  35        .idsetup        = _idsetup,             \
  36        .uncompress     = _uncompress,          \
  37        .compress       = _compress,            \
  38}
  39
  40#define module_lowpan_nhc(__nhc)                \
  41static int __init __nhc##_init(void)            \
  42{                                               \
  43        return lowpan_nhc_add(&(__nhc));        \
  44}                                               \
  45module_init(__nhc##_init);                      \
  46static void __exit __nhc##_exit(void)           \
  47{                                               \
  48        lowpan_nhc_del(&(__nhc));               \
  49}                                               \
  50module_exit(__nhc##_exit);
  51
  52/**
  53 * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
  54 *
  55 * @node: holder for the rbtree.
  56 * @name: name of the specific next header compression
  57 * @nexthdr: next header value of the protocol which should be compressed.
  58 * @nexthdrlen: ipv6 nexthdr len for the reserved space.
  59 * @id: array for nhc id. Note this need to be in network byteorder.
  60 * @mask: array for nhc id mask. Note this need to be in network byteorder.
  61 * @len: the length of the next header id and mask.
  62 * @setup: callback to setup fill the next header id value and mask.
  63 * @compress: callback to do the header compression.
  64 * @uncompress: callback to do the header uncompression.
  65 */
  66struct lowpan_nhc {
  67        struct rb_node  node;
  68        const char      *name;
  69        const u8        nexthdr;
  70        const size_t    nexthdrlen;
  71        u8              *id;
  72        u8              *idmask;
  73        const size_t    idlen;
  74
  75        void            (*idsetup)(struct lowpan_nhc *nhc);
  76        int             (*uncompress)(struct sk_buff *skb, size_t needed);
  77        int             (*compress)(struct sk_buff *skb, u8 **hc_ptr);
  78};
  79
  80/**
  81 * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
  82 *
  83 * @nexthdr: ipv6 nexthdr value.
  84 */
  85struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
  86
  87/**
  88 * lowpan_nhc_check_compression - checks if we support compression format. If
  89 *      we support the nhc by nexthdr field, the function will return 0. If we
  90 *      don't support the nhc by nexthdr this function will return -ENOENT.
  91 *
  92 * @skb: skb of 6LoWPAN header to read nhc and replace header.
  93 * @hdr: ipv6hdr to check the nexthdr value
  94 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
  95 *          replaced header.
  96 */
  97int lowpan_nhc_check_compression(struct sk_buff *skb,
  98                                 const struct ipv6hdr *hdr, u8 **hc_ptr);
  99
 100/**
 101 * lowpan_nhc_do_compression - calling compress callback for nhc
 102 *
 103 * @skb: skb of 6LoWPAN header to read nhc and replace header.
 104 * @hdr: ipv6hdr to set the nexthdr value
 105 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
 106 *          replaced header.
 107 */
 108int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
 109                              u8 **hc_ptr);
 110
 111/**
 112 * lowpan_nhc_do_uncompression - calling uncompress callback for nhc
 113 *
 114 * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
 115 * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
 116 * @dev: netdevice for print logging information.
 117 * @hdr: ipv6hdr for setting nexthdr value.
 118 */
 119int lowpan_nhc_do_uncompression(struct sk_buff *skb,
 120                                const struct net_device *dev,
 121                                struct ipv6hdr *hdr);
 122
 123/**
 124 * lowpan_nhc_add - register a next header compression to framework
 125 *
 126 * @nhc: nhc which should be add.
 127 */
 128int lowpan_nhc_add(struct lowpan_nhc *nhc);
 129
 130/**
 131 * lowpan_nhc_del - delete a next header compression from framework
 132 *
 133 * @nhc: nhc which should be delete.
 134 */
 135void lowpan_nhc_del(struct lowpan_nhc *nhc);
 136
 137/**
 138 * lowpan_nhc_init - adding all default nhcs
 139 */
 140void lowpan_nhc_init(void);
 141
 142#endif /* __6LOWPAN_NHC_H */
 143