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