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/* Copyright (C) 2024 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/*!
* \file
*
* \brief Zone scanner core interface.
*
* \addtogroup zscanner
* @{
*/
#pragma once
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "libzscanner/error.h"
/*! \brief Maximal length of rdata. */
#define ZS_MAX_RDATA_LENGTH 65535
/*! \brief Maximal length of domain name. */
#define ZS_MAX_DNAME_LENGTH 255
/*! \brief Maximal length of domain name label. */
#define ZS_MAX_LABEL_LENGTH 63
/*! \brief Length of ipv4 address in the wire format. */
#define ZS_INET4_ADDR_LENGTH 4
/*! \brief Length of ipv6 address in the wire format. */
#define ZS_INET6_ADDR_LENGTH 16
/*! \brief Number of bitmap windows. */
#define ZS_BITMAP_WINDOWS 256
/*! \brief Ragel call stack size (see Ragel internals). */
#define ZS_RAGEL_STACK_SIZE 16
/*! \brief Auxiliary structure for storing bitmap window items (see RFC4034). */
typedef struct {
uint8_t bitmap[32];
uint8_t length;
} zs_win_t;
/*! \brief Auxiliary structure for storing one APL record (see RFC3123). */
typedef struct {
uint8_t excl_flag;
uint16_t addr_family;
uint8_t prefix_length;
} zs_apl_t;
/*! \brief Auxiliary structure for storing LOC information (see RFC1876). */
typedef struct {
uint32_t d1, d2;
uint32_t m1, m2;
uint32_t s1, s2;
uint32_t alt;
uint64_t siz, hp, vp;
int8_t lat_sign, long_sign, alt_sign;
} zs_loc_t;
/*! \brief Auxiliary structure for storing SVCB information. */
typedef struct {
uint8_t *params_position;
uint8_t *mandatory_position;
uint8_t *param_position;
int32_t last_key;
} zs_svcb_t;
/*! \brief Scanner states describing the result. */
typedef enum {
ZS_STATE_NONE, /*!< Initial state (no data). */
ZS_STATE_DATA, /*!< A record parsed. */
ZS_STATE_ERROR, /*!< An error occurred. */
ZS_STATE_INCLUDE, /*!< An include directive (see include_filename, buffer). */
ZS_STATE_EOF, /*!< The end of the current input reached. */
ZS_STATE_STOP /*!< Early stop (possibly set from a callback). */
} zs_state_t;
/*!
* \brief Context structure for zone scanner.
*
* This structure contains following items:
* - Copies of Ragel internal variables. The scanner can be called many times
* on smaller parts of zone file/memory. So it is necessary to preserve
* internal values between subsequent scanner callings.
* - Auxiliary variables which are used during processing zone data.
* - Pointers to callback functions and pointer to any arbitrary data which
* can be used in callback functions.
* - Zone file and error information.
* - Output variables (r_ prefix) containing all parts of zone record. These
* data are useful during processing via callback function.
*/
typedef struct zs_scanner zs_scanner_t; // Forward declaration due to arguments.
struct zs_scanner {
/*! Current state (Ragel internals). */
int cs;
/*! Stack top (Ragel internals). */
int top;
/*! Call stack (Ragel internals). */
int stack[ZS_RAGEL_STACK_SIZE];
/*! Indicates whether current record is multiline. */
bool multiline;
/*! Auxiliary number for all numeric operations. */
uint64_t number64;
/*! Auxiliary variable for time and other numeric operations. */
uint64_t number64_tmp;
/*! Auxiliary variable for float numeric operations. */
uint32_t decimals;
/*! Auxiliary variable for float numeric operations. */
uint32_t decimal_counter;
/*! Auxiliary variable for item length (label, base64, ...). */
uint32_t item_length;
/*! Auxiliary index for item length position in array. */
uint32_t item_length_position;
/*! Auxiliary pointer to item length. */
uint8_t *item_length_location;
/*! Auxiliary 2-byte length locator. */
uint8_t *item_length2_location;
/*! Auxiliary buffer length. Is zero if no comment after a valid record. */
uint32_t buffer_length;
/*! Auxiliary buffer. Contains a comment after a valid record. */
uint8_t buffer[ZS_MAX_RDATA_LENGTH];
/*! Auxiliary buffer for current included file name. */
char include_filename[ZS_MAX_RDATA_LENGTH];
/*! Absolute path for relative includes. */
char *path;
/*! Auxiliary array of bitmap window blocks. */
zs_win_t windows[ZS_BITMAP_WINDOWS];
/*! Last window block which is used (-1 means no window). */
int16_t last_window;
/*! Auxiliary apl structure. */
zs_apl_t apl;
/*! Auxiliary loc structure. */
zs_loc_t loc;
/*! Auxiliary svcb structure. */
zs_svcb_t svcb;
/*! Auxiliary IP address storage. */
uint8_t addr[ZS_INET6_ADDR_LENGTH];
/*! Allow text strings longer than 255 characters. */
bool long_string;
/*! Comma separated string list indication (svcb parsing). */
bool comma_list;
/*! Indication of a non-applied backslash. */
bool pending_backslash;
/*! Pointer to the actual dname storage (origin/owner/rdata). */
uint8_t *dname;
/*! Pointer to the actual dname length storage. */
uint32_t *dname_length;
/*!
* Temporary dname length which is copied to dname_length after
* dname processing.
*/
uint32_t dname_tmp_length;
/*! Position of the last free r_data byte. */
uint32_t r_data_tail;
/*! Length of the current origin. */
uint32_t zone_origin_length;
/*!
* Wire format of the current origin (ORIGIN directive sets this).
*
* \note Maximal dname length check is after each valid label.
*/
uint8_t zone_origin[ZS_MAX_DNAME_LENGTH + ZS_MAX_LABEL_LENGTH];
/*! Value of the default class. */
uint16_t default_class;
/*! Value of the current default ttl (TTL directive sets this). */
uint32_t default_ttl;
/*! The current processing state. */
zs_state_t state;
/*! Processing callbacks and auxiliary data. */
struct {
/*! Automatic zone processing using record/error callbacks. */
bool automatic;
/*! Callback function for correct zone record. */
void (*record)(zs_scanner_t *);
/*! Callback function for wrong situations. */
void (*error)(zs_scanner_t *);
/*! Callback function for pure comment line. */
void (*comment)(zs_scanner_t *);
/*! Arbitrary data useful inside callback functions. */
void *data;
} process;
/*! Input parameters. */
struct {
/*! Start of the block. */
const char *start;
/*! Current parser position. */
const char *current;
/*! End of the block. */
const char *end;
/*! Indication for the final block parsing. */
bool eof;
/*! Indication of being mmap()-ed (malloc()-ed otherwise). */
bool mmaped;
} input;
/*! File input parameters. */
struct {
/*! Zone file name. */
char *name;
/*!< File descriptor. */
int descriptor;
} file;
struct {
/*! Last occurred error/warning code. */
int code;
/*! Error/warning counter. */
uint64_t counter;
/*! Indicates serious error - parsing cannot continue. */
bool fatal;
} error;
/*! Zone data line counter. */
uint64_t line_counter;
/*! Length of the current record owner. */
uint32_t r_owner_length;
/*!
* Owner of the current record.
*
* \note Maximal dname length check is after each valid label.
*/
uint8_t r_owner[ZS_MAX_DNAME_LENGTH + ZS_MAX_LABEL_LENGTH];
/*! Class of the current record. */
uint16_t r_class;
/*! TTL of the current record. */
uint32_t r_ttl;
/*! Type of the current record data. */
uint16_t r_type;
/*! Length of the current rdata. */
uint32_t r_data_length;
/*! Current rdata. */
uint8_t r_data[ZS_MAX_RDATA_LENGTH];
/*
* Example: a. IN 60 MX 1 b. ; A comment
*
* r_owner_length = 3
* r_owner = 016100
* r_class = 1
* r_ttl = 60
* r_type = 15
* r_data_length = 5
* r_data = 0001016200
* buffer_length = 11
* buffer = " A comment"
*/
};
/*!
* \brief Initializes the scanner context.
*
* \note Error code is stored in the scanner context.
*
* \param scanner Scanner context.
* \param origin Initial zone origin.
* \param rclass Zone class value.
* \param ttl Initial ttl value.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_init(
zs_scanner_t *scanner,
const char *origin,
const uint16_t rclass,
const uint32_t ttl
);
/*!
* \brief Deinitializes the scanner context.
*
* \param scanner Scanner context.
*/
void zs_deinit(
zs_scanner_t *scanner
);
/*!
* \brief Sets the scanner to parse a zone data string.
*
* \note Error code is stored in the scanner context.
*
* \param scanner Scanner context.
* \param input Input zone data string to parse.
* \param size Size of the input string.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_set_input_string(
zs_scanner_t *scanner,
const char *input,
size_t size
);
/*!
* \brief Sets the scanner to parse a zone file.
*
* \note Error code is stored in the scanner context.
*
* \param scanner Scanner context.
* \param file_name Name of the file to parse.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_set_input_file(
zs_scanner_t *scanner,
const char *file_name
);
/*!
* \brief Sets the scanner processing callbacks for automatic processing.
*
* \note Error code is stored in the scanner context.
*
* \param scanner Scanner context.
* \param process_record Processing callback function (may be NULL).
* \param process_error Error callback function (may be NULL).
* \param data Arbitrary data useful in callback functions.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_set_processing(
zs_scanner_t *scanner,
void (*process_record)(zs_scanner_t *),
void (*process_error)(zs_scanner_t *),
void *data
);
/*!
* \brief Sets the scanner comment processing callback for automatic processing.
*
* \note If the comment is after a valid resource record, the callback is
* executed before a record processing callback!
* \note Optional data must be set via zs_set_processing.
*
* \param scanner Scanner context.
* \param process_comment Processing callback function (may be NULL).
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_set_processing_comment(
zs_scanner_t *scanner,
void (*process_comment)(zs_scanner_t *)
);
/*!
* \brief Parses one record from the input.
*
* The following processing should be based on the scanner->state.
*
* \note Error code and other information are stored in the scanner context.
*
* \param scanner Scanner context.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_parse_record(
zs_scanner_t *scanner
);
/*!
* \brief Launches automatic parsing of the whole input.
*
* For each correctly recognized record, the record callback is executed.
* If any syntax error occurs, the error callback is executed.
*
* \note Error code and other information are stored in the scanner context.
*
* \param scanner Scanner context.
*
* \retval 0 if success.
* \retval -1 if error.
*/
int zs_parse_all(
zs_scanner_t *scanner
);
/*! @} */
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