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) \ 27static u8 __nhc##_val[_idlen]; \ 28static u8 __nhc##_mask[_idlen]; \ 29static 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) \ 42static int __init __nhc##_init(void) \ 43{ \ 44 return lowpan_nhc_add(&(__nhc)); \ 45} \ 46module_init(__nhc##_init); \ 47static void __exit __nhc##_exit(void) \ 48{ \ 49 lowpan_nhc_del(&(__nhc)); \ 50} \ 51module_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 */ 67struct 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 */ 86struct 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 */ 98int 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 */ 109int 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 */ 120int 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 */ 129int 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 */ 136void lowpan_nhc_del(struct lowpan_nhc *nhc); 137 138/** 139 * lowpan_nhc_init - adding all default nhcs 140 */ 141void lowpan_nhc_init(void); 142 143#endif /* __6LOWPAN_NHC_H */ 144