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 * @_id: one byte nhc id value. 20 * @_idmask: one byte nhc id mask value. 21 * @_uncompress: callback for uncompression call. 22 * @_compress: callback for compression call. 23 */ 24 #define LOWPAN_NHC(__nhc, _name, _nexthdr, \ 25 _hdrlen, _id, _idmask, \ 26 _uncompress, _compress) \ 27 static const struct lowpan_nhc __nhc = { \ 28 .name = _name, \ 29 .nexthdr = _nexthdr, \ 30 .nexthdrlen = _hdrlen, \ 31 .id = _id, \ 32 .idmask = _idmask, \ 33 .uncompress = _uncompress, \ 34 .compress = _compress, \ 35 } 36 37 #define module_lowpan_nhc(__nhc) \ 38 static int __init __nhc##_init(void) \ 39 { \ 40 return lowpan_nhc_add(&(__nhc)); \ 41 } \ 42 module_init(__nhc##_init); \ 43 static void __exit __nhc##_exit(void) \ 44 { \ 45 lowpan_nhc_del(&(__nhc)); \ 46 } \ 47 module_exit(__nhc##_exit); 48 49 /** 50 * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation 51 * 52 * @name: name of the specific next header compression 53 * @nexthdr: next header value of the protocol which should be compressed. 54 * @nexthdrlen: ipv6 nexthdr len for the reserved space. 55 * @id: one byte nhc id value. 56 * @idmask: one byte nhc id mask value. 57 * @compress: callback to do the header compression. 58 * @uncompress: callback to do the header uncompression. 59 */ 60 struct lowpan_nhc { 61 const char *name; 62 u8 nexthdr; 63 size_t nexthdrlen; 64 u8 id; 65 u8 idmask; 66 67 int (*uncompress)(struct sk_buff *skb, size_t needed); 68 int (*compress)(struct sk_buff *skb, u8 **hc_ptr); 69 }; 70 71 /** 72 * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr. 73 * 74 * @nexthdr: ipv6 nexthdr value. 75 */ 76 struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr); 77 78 /** 79 * lowpan_nhc_check_compression - checks if we support compression format. If 80 * we support the nhc by nexthdr field, the function will return 0. If we 81 * don't support the nhc by nexthdr this function will return -ENOENT. 82 * 83 * @skb: skb of 6LoWPAN header to read nhc and replace header. 84 * @hdr: ipv6hdr to check the nexthdr value 85 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of 86 * replaced header. 87 */ 88 int lowpan_nhc_check_compression(struct sk_buff *skb, 89 const struct ipv6hdr *hdr, u8 **hc_ptr); 90 91 /** 92 * lowpan_nhc_do_compression - calling compress callback for nhc 93 * 94 * @skb: skb of 6LoWPAN header to read nhc and replace header. 95 * @hdr: ipv6hdr to set the nexthdr value 96 * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of 97 * replaced header. 98 */ 99 int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, 100 u8 **hc_ptr); 101 102 /** 103 * lowpan_nhc_do_uncompression - calling uncompress callback for nhc 104 * 105 * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions. 106 * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value. 107 * @dev: netdevice for print logging information. 108 * @hdr: ipv6hdr for setting nexthdr value. 109 */ 110 int lowpan_nhc_do_uncompression(struct sk_buff *skb, 111 const struct net_device *dev, 112 struct ipv6hdr *hdr); 113 114 /** 115 * lowpan_nhc_add - register a next header compression to framework 116 * 117 * @nhc: nhc which should be add. 118 */ 119 int lowpan_nhc_add(const struct lowpan_nhc *nhc); 120 121 /** 122 * lowpan_nhc_del - delete a next header compression from framework 123 * 124 * @nhc: nhc which should be delete. 125 */ 126 void lowpan_nhc_del(const struct lowpan_nhc *nhc); 127 128 /** 129 * lowpan_nhc_init - adding all default nhcs 130 */ 131 void lowpan_nhc_init(void); 132 133 #endif /* __6LOWPAN_NHC_H */ 134