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#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