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)      \
  26 static u8 __nhc##_val[_idlen];                  \
  27 static u8 __nhc##_mask[_idlen];                 \
  28 static 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)                \
  41 static int __init __nhc##_init(void)            \
  42 {                                               \
  43         return lowpan_nhc_add(&(__nhc));        \
  44 }                                               \
  45 module_init(__nhc##_init);                      \
  46 static void __exit __nhc##_exit(void)           \
  47 {                                               \
  48         lowpan_nhc_del(&(__nhc));               \
  49 }                                               \
  50 module_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  */
  66 struct 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  */
  85 struct 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  */
  97 int 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  */
 108 int 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  */
 119 int 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  */
 128 int 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  */
 135 void lowpan_nhc_del(struct lowpan_nhc *nhc);
 136
 137 /**
 138  * lowpan_nhc_init - adding all default nhcs
 139  */
 140 void lowpan_nhc_init(void);
 141
 142 #endif /* __6LOWPAN_NHC_H */