nhc.h
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#ifndef __6LOWPAN_NHC_H
#define __6LOWPAN_NHC_H
#include <linux/skbuff.h>
#include <linux/rbtree.h>
#include <linux/module.h>
#include <net/6lowpan.h>
#include <net/ipv6.h>
/**
* LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct
*
* @__nhc: variable name of the lowpan_nhc struct.
* @_name: const char * of common header compression name.
* @_nexthdr: ipv6 nexthdr field for the header compression.
* @_nexthdrlen: ipv6 nexthdr len for the reserved space.
* @_idsetup: callback to setup id and mask values.
* @_idlen: len for the next header id and mask, should be always the same.
* @_uncompress: callback for uncompression call.
* @_compress: callback for compression call.
*/
#define LOWPAN_NHC(__nhc, _name, _nexthdr, \
_hdrlen, _idsetup, _idlen, \
_uncompress, _compress) \
static u8 __nhc##_val[_idlen]; \
static u8 __nhc##_mask[_idlen]; \
static struct lowpan_nhc __nhc = { \
.name = _name, \
.nexthdr = _nexthdr, \
.nexthdrlen = _hdrlen, \
.id = __nhc##_val, \
.idmask = __nhc##_mask, \
.idlen = _idlen, \
.idsetup = _idsetup, \
.uncompress = _uncompress, \
.compress = _compress, \
}
#define module_lowpan_nhc(__nhc) \
static int __init __nhc##_init(void) \
{ \
return lowpan_nhc_add(&(__nhc)); \
} \
module_init(__nhc##_init); \
static void __exit __nhc##_exit(void) \
{ \
lowpan_nhc_del(&(__nhc)); \
} \
module_exit(__nhc##_exit);
/**
* struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation
*
* @node: holder for the rbtree.
* @name: name of the specific next header compression
* @nexthdr: next header value of the protocol which should be compressed.
* @nexthdrlen: ipv6 nexthdr len for the reserved space.
* @id: array for nhc id. Note this need to be in network byteorder.
* @mask: array for nhc id mask. Note this need to be in network byteorder.
* @len: the length of the next header id and mask.
* @setup: callback to setup fill the next header id value and mask.
* @compress: callback to do the header compression.
* @uncompress: callback to do the header uncompression.
*/
struct lowpan_nhc {
struct rb_node node;
const char *name;
const u8 nexthdr;
const size_t nexthdrlen;
u8 *id;
u8 *idmask;
const size_t idlen;
void (*idsetup)(struct lowpan_nhc *nhc);
int (*uncompress)(struct sk_buff *skb, size_t needed);
int (*compress)(struct sk_buff *skb, u8 **hc_ptr);
};
/**
* lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr.
*
* @nexthdr: ipv6 nexthdr value.
*/
struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr);
/**
* lowpan_nhc_check_compression - checks if we support compression format. If
* we support the nhc by nexthdr field, the function will return 0. If we
* don't support the nhc by nexthdr this function will return -ENOENT.
*
* @skb: skb of 6LoWPAN header to read nhc and replace header.
* @hdr: ipv6hdr to check the nexthdr value
* @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
* replaced header.
*/
int lowpan_nhc_check_compression(struct sk_buff *skb,
const struct ipv6hdr *hdr, u8 **hc_ptr);
/**
* lowpan_nhc_do_compression - calling compress callback for nhc
*
* @skb: skb of 6LoWPAN header to read nhc and replace header.
* @hdr: ipv6hdr to set the nexthdr value
* @hc_ptr: pointer for 6LoWPAN header which should increment at the end of
* replaced header.
*/
int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr,
u8 **hc_ptr);
/**
* lowpan_nhc_do_uncompression - calling uncompress callback for nhc
*
* @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions.
* @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value.
* @dev: netdevice for print logging information.
* @hdr: ipv6hdr for setting nexthdr value.
*/
int lowpan_nhc_do_uncompression(struct sk_buff *skb,
const struct net_device *dev,
struct ipv6hdr *hdr);
/**
* lowpan_nhc_add - register a next header compression to framework
*
* @nhc: nhc which should be add.
*/
int lowpan_nhc_add(struct lowpan_nhc *nhc);
/**
* lowpan_nhc_del - delete a next header compression from framework
*
* @nhc: nhc which should be delete.
*/
void lowpan_nhc_del(struct lowpan_nhc *nhc);
/**
* lowpan_nhc_init - adding all default nhcs
*/
void lowpan_nhc_init(void);
#endif /* __6LOWPAN_NHC_H */