compress.h revision 7d32c065c7bb56f281651ae3dd2888f32ce4f1d9
/*
* Copyright (C) 1999, 2000 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#ifndef DNS_COMPRESS_H
#define DNS_COMPRESS_H 1
#include <isc/mem.h>
#include <isc/lang.h>
#include <dns/types.h>
#include <dns/rbt.h>
ISC_LANG_BEGINDECLS
#define DNS_COMPRESS_NONE 0x00 /* no compression */
#define DNS_COMPRESS_GLOBAL14 0x01 /* "normal" compression. */
#define DNS_COMPRESS_GLOBAL16 0x02 /* 16-bit global comp. */
#define DNS_COMPRESS_GLOBAL 0x03 /* all global comp. */
#define DNS_COMPRESS_LOCAL 0x04 /* local compression. */
#define DNS_COMPRESS_ALL 0x07 /* all compression. */
/*
* XXX An API for manipulating these structures will be forthcoming.
* Also magic numbers, _init() and _invalidate(), etc. At that time,
* direct manipulation of the structures will be strongly discouraged.
*/
struct dns_compress {
unsigned int magic; /* Magic number. */
unsigned int allowed; /* Allowed methods. */
unsigned int rdata; /* Start of local rdata. */
isc_boolean_t global16; /* 16 bit offsets allowed. */
int edns; /* Edns version or -1. */
dns_rbt_t *local; /* Local RBT. */
dns_rbt_t *global; /* Global RBT. */
isc_mem_t *mctx; /* Memeory context. */
};
struct dns_decompress {
unsigned int magic; /* Magic number. */
unsigned int allowed; /* Allowed methods. */
unsigned int rdata; /* Start of local rdata. */
int edns; /* Edns version or -1. */
isc_boolean_t strict; /* Strict checking */
dns_name_t owner_name; /* For local compression. */
};
isc_result_t dns_compress_init(dns_compress_t *cctx, int edns,
isc_mem_t *mctx);
/*
* Inialise the compression context structure pointed to by 'cctx'.
*
* Requires:
* 'cctx' is a valid dns_compress_t structure.
* 'mctx' is a initalised memory context.
* Ensures:
* cctx->global is initalised.
*
* Returns:
* DNS_R_SUCCESS
* failures from dns_rbt_create()
*/
isc_result_t
dns_compress_localinit(dns_compress_t *cctx, dns_name_t *owner,
isc_buffer_t *target);
/*
* Initalise 'cctx->local'.
* All compression pointers pointing to logical labels in owner.
* Record start of rdata 'target->used'.
*
* Ensures:
* 'cctx->local' is valid.
*
* Requires:
* 'cctx' initaliased
* 'cctx->local' be NULL
* 'owner' is a absolute name
* 'target' is a valid buffer
*
* Returns:
* DNS_R_SUCCESS
* failures from dns_rbt_create()
*/
void
dns_compress_invalidate(dns_compress_t *cctx);
/*
* Invalidate the compression structure pointed to by cctx.
* Destroys 'cctx->glocal' and 'cctx->local' RBT.
*
* Requires:
* 'cctx' to be initalised.
*/
void
dns_compress_localinvalidate(dns_compress_t *cctx);
/*
* Destroys 'cctx->local'.
*
* Requires:
* 'cctx' to be initalised.
*/
void
dns_compress_setmethods(dns_compress_t *cctx, unsigned int allowed);
/*
* Sets allowed compression methods.
*
* Requires:
* 'cctx' to be initalised.
*/
unsigned int
dns_compress_getmethods(dns_compress_t *cctx);
/*
* Gets allowed compression methods.
*
* Requires:
* 'cctx' to be initalised.
*
* Returns:
* allowed compression bitmap.
*/
int
dns_compress_getedns(dns_compress_t *cctx);
/*
* Gets edns value.
*
* Requires:
* 'cctx' to be initalised.
*
* Returns:
* -1 .. 255
*/
isc_boolean_t
dns_compress_findglobal(dns_compress_t *cctx, dns_name_t *name,
dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t *offset, isc_buffer_t *workspace);
/*
* Finds longest possible match of 'name' in the global compression
* RBT. Workspace needs to be large enough to hold 'name' when split
* in two (length->name + 3).
*
* Requires:
* 'cctx' to be initalised.
* 'name' to be a absolute name.
* 'prefix' to be initalised.
* 'suffix' to be initalised.
* 'offset' to point it a isc_uint16_t.
* 'workspace' to be initalised.
*
* Ensures:
* 'prefix', 'suffix' and 'offset' are valid if ISC_TRUE is
* returned.
*
* Returns:
* ISC_TRUE / ISC_FALSE
*/
isc_boolean_t
dns_compress_findlocal(dns_compress_t *cctx, dns_name_t *name,
dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t *offset, isc_buffer_t *workspace);
/*
* Finds longest possible match of 'name' in the local compression
* RBT. Workspace needs to be large enough to hold 'name' when split
* in two (length->name + 3).
*
* Requires:
* 'cctx' to be initalised.
* 'name' to be a absolute name.
* 'prefix' to be initalised.
* 'suffix' to be initalised.
* 'offset' to point to a isc_uint16_t.
* 'workspace' to be initalised.
*
* Ensures:
* 'prefix', 'suffix' and 'offset' are valid is ISC_TRUE is
* returned.
*
* Returns:
* ISC_TRUE / ISC_FALSE
*/
void
dns_compress_add(dns_compress_t *cctx, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t offset,
isc_boolean_t local);
/*
* Add compression pointers for labels in prefix to RBT's.
* If 'prefix' is absolute 'suffix' must be NULL otherwise
* suffix must be absolute.
* 'local' indicates that the domain name at offset contains
* a local compression pointer.
*
* Requires:
* 'cctx' initalised
* 'prefix' to be initalised
* 'suffix' to be initalised or NULL
*/
void
dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset);
/*
* Remove any compression pointers from global RBT >= offset.
*
* Requires:
* 'cctx' is initalised.
*/
void
dns_decompress_init(dns_decompress_t *dctx, int edns, isc_boolean_t strict);
/*
* Initalises 'dctx'.
* Records 'edns' and 'strict' into the structure.
*
* Requires:
* 'dctx' to be a valid pointer.
*/
void
dns_decompress_localinit(dns_decompress_t *dctx, dns_name_t *name,
isc_buffer_t *source);
/*
* Initalises 'dctx->name' from name.
* Records 'source->current' as the start of the rdata section.
*
* Requires:
* 'dctx' to be initalised
* 'name' to be absolute
* 'source' to be a BINARY buffer.
*/
void
dns_decompress_invalidate(dns_decompress_t *dctx);
/*
* Invalidates 'dctx'.
*
* Requires:
* 'dctx' to be initalised
*/
void
dns_decompress_localinvalidate(dns_decompress_t *dctx);
/*
* Invalidates 'dctx->name'.
*
* Requires:
* 'dctx' to be initalised
*/
void
dns_decompress_setmethods(dns_decompress_t *dctx, unsigned int allowed);
/*
* Sets 'dctx->allowed' to 'allowed'.
*
* Requires:
* 'dctx' to be initalised
*/
unsigned int
dns_decompress_getmethods(dns_decompress_t *dctx);
/*
* Returns 'dctx->allowed'
*
* Requires:
* 'dctx' to be initalised
*/
int
dns_decompress_edns(dns_decompress_t *dctx);
/*
* Returns 'dctx->edns'
*
* Requires:
* 'dctx' to be initalised
*/
isc_boolean_t
dns_decompress_strict(dns_decompress_t *dctx);
/*
* Returns 'dctx->strict'
*
* Requires:
* 'dctx' to be initalised
*/
ISC_LANG_ENDDECLS
#endif /* DNS_COMPRESS_H */