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)      \
  28 static u8 __nhc##_val[_idlen];                  \
  29 static u8 __nhc##_mask[_idlen];                 \
  30 static 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)                \
  43 static int __init __nhc##_init(void)            \
  44 {                                               \
  45         return lowpan_nhc_add(&(__nhc));        \
  46 }                                               \
  47 module_init(__nhc##_init);                      \
  48 static void __exit __nhc##_exit(void)           \
  49 {                                               \
  50         lowpan_nhc_del(&(__nhc));               \
  51 }                                               \
  52 module_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  */
  68 struct 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  */
  87 struct 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  */
 101 int 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  */
 113 int 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  */
 124 int 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  */
 132 int 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  */
 139 void lowpan_nhc_del(struct lowpan_nhc *nhc);
 140
 141 /**
 142  * lowpan_nhc_init - adding all default nhcs
 143  */
 144 void lowpan_nhc_init(void);
 145
 146 #endif /* __6LOWPAN_NHC_H */