dns.h File Reference

Implementation of the DNS protocol. More...

#include <freeradius-devel/util/packet.h>
#include <freeradius-devel/util/dns.h>

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Data Structures
struct	fr_dns_attr_flags_t
struct	fr_dns_ctx_t
struct	fr_dns_packet_t

Macros
#define	DNS_HDR_LEN   (12)
#define	DNS_MAX_ATTRIBUTES   255
#define	FR_DNS_PACKET_CODE_VALID(_code)   (((_code) < FR_DNS_CODE_MAX) || (((_code & 0x10) != 0) && ((_code & ~0x10) < FR_DNS_CODE_MAX)))

Enumerations
enum	fr_dns_decode_fail_t {   FR_DNS_DECODE_FAIL_NONE = 0 ,   FR_DNS_DECODE_FAIL_UNKNOWN_OPCODE ,   FR_DNS_DECODE_FAIL_MIN_LENGTH_PACKET ,   FR_DNS_DECODE_FAIL_MAX_LENGTH_PACKET ,   FR_DNS_DECODE_FAIL_UNEXPECTED ,   FR_DNS_DECODE_FAIL_NO_QUESTIONS ,   FR_DNS_DECODE_FAIL_ANSWERS_IN_QUESTION ,   FR_DNS_DECODE_FAIL_NS_IN_QUESTION ,   FR_DNS_DECODE_FAIL_INVALID_RR_LABEL ,   FR_DNS_DECODE_FAIL_MISSING_RR_HEADER ,   FR_DNS_DECODE_FAIL_MISSING_RR_LEN ,   FR_DNS_DECODE_FAIL_ZERO_RR_LEN ,   FR_DNS_DECODE_FAIL_RR_OVERFLOWS_PACKET ,   FR_DNS_DECODE_FAIL_TOO_MANY_RRS ,   FR_DNS_DECODE_FAIL_TOO_FEW_RRS ,   FR_DNS_DECODE_FAIL_POINTER_TO_NON_LABEL ,   FR_DNS_DECODE_FAIL_POINTER_OVERFLOWS_PACKET ,   FR_DNS_DECODE_FAIL_POINTER_TO_HEADER ,   FR_DNS_DECODE_FAIL_POINTER_LOOPS ,   FR_DNS_DECODE_FAIL_INVALID_POINTER ,   FR_DNS_DECODE_FAIL_LABEL_OVERFLOWS_PACKET ,   FR_DNS_DECODE_FAIL_LABEL_TOO_LONG ,   FR_DNS_DECODE_FAIL_MISSING_QD_HEADER ,   FR_DNS_DECODE_FAIL_MISSING_TLV_HEADER ,   FR_DNS_DECODE_FAIL_TLV_OVERFLOWS_RR ,   FR_DNS_DECODE_FAIL_TRUNCATED ,   FR_DNS_DECODE_FAIL_MAX }
enum	fr_dns_packet_code_t {   FR_DNS_QUERY = 0 ,   FR_DNS_INVERSE_QUERY = 1 ,   FR_DNS_STATUS = 2 ,   FR_DNS_NOTIFY = 4 ,   FR_DNS_UPDATE = 5 ,   FR_DNS_STATEFUL_OPERATION = 6 ,   FR_DNS_CODE_MAX = 7 ,   FR_DNS_QUERY_RESPONSE = 16 ,   FR_DNS_INVERSE_QUERY_RESPONSE = 17 ,   FR_DNS_STATUS_RESPONSE = 18 ,   FR_DNS_NOTIFY_RESPONSE = 20 ,   FR_DNS_UPDATE_RESPONSE = 21 ,   FR_DNS_STATEFUL_OPERATION_RESPONSE = 22 ,   FR_DNS_DO_NOT_RESPOND = 256 }

Functions
static fr_dns_attr_flags_t const *	fr_dns_attr_flags (fr_dict_attr_t const *da)
	Return DNS-specific flags for a given attribute.
ssize_t	fr_dns_decode (TALLOC_CTX *ctx, fr_pair_list_t *out, uint8_t const *packet, size_t packet_len, fr_dns_ctx_t *packet_ctx)
	Decode a DNS packet.
ssize_t	fr_dns_encode (fr_dbuff_t *dbuff, fr_pair_list_t *vps, fr_dns_ctx_t *encode_ctx)
	Encode a DNS packet.
static bool	fr_dns_flag_dns_label (fr_dict_attr_t const *da)
static bool	fr_dns_flag_dns_label_any (fr_dict_attr_t const *da)
static bool	fr_dns_flag_dns_label_uncompressed (fr_dict_attr_t const *da)
void	fr_dns_global_free (void)
int	fr_dns_global_init (void)
	Resolve/cache attributes in the DNS dictionary.
fr_dns_labels_t *	fr_dns_labels_get (uint8_t const *packet, size_t packet_len, bool init_mark)
bool	fr_dns_packet_ok (uint8_t const *packet, size_t packet_len, bool query, fr_dns_decode_fail_t *reason)

Variables
char const *	fr_dns_packet_names [FR_DNS_CODE_MAX]
fr_table_num_ordered_t	fr_dns_reason_fail_table []
size_t	fr_dns_reason_fail_table_len
fr_dict_protocol_t	libfreeradius_dns_dict_protocol

Detailed Description

Implementation of the DNS protocol.

Id

8dbafb00c9106e0e782941e306197bb36d28a37c

Copyright

2021 Network RADIUS SAS (legal.nosp@m.@net.nosp@m.workr.nosp@m.adiu.nosp@m.s.com)

Definition in file dns.h.

---

Data Structure Documentation

fr_dns_attr_flags_t

struct fr_dns_attr_flags_t

Definition at line 136 of file dns.h.

Data Fields
bool	dns_label
bool	dns_label_uncompressed

fr_dns_ctx_t

struct fr_dns_ctx_t

Definition at line 73 of file dns.h.

Collaboration diagram for fr_dns_ctx_t:

Data Fields
fr_dns_labels_t *	lb
uint8_t const *	packet	DNS labels can point anywhere in the packet :(.
size_t	packet_len
TALLOC_CTX *	tmp_ctx	for temporary things cleaned up during decoding

fr_dns_packet_t

struct fr_dns_packet_t

Definition at line 37 of file dns.h.

Data Fields
uint16_t	ancount
uint16_t	arcount
unsigned int	authentic_data: 1
unsigned int	authoritative: 1
unsigned int	checking_disabled: 1
uint16_t	id
uint16_t	nscount
unsigned int	opcode: 4
uint16_t	qdcount
unsigned int	query: 1
unsigned int	rcode: 4
unsigned int	recursion_available: 1
unsigned int	recursion_desired: 1
unsigned int	reserved: 1
unsigned int	truncated: 1

Macro Definition Documentation

DNS_HDR_LEN

#define DNS_HDR_LEN   (12)

Definition at line 134 of file dns.h.

DNS_MAX_ATTRIBUTES

#define DNS_MAX_ATTRIBUTES   255

Definition at line 35 of file dns.h.

FR_DNS_PACKET_CODE_VALID

#define FR_DNS_PACKET_CODE_VALID

(

_code

)

(((_code) < FR_DNS_CODE_MAX) || (((_code & 0x10) != 0) && ((_code & ~0x10) < FR_DNS_CODE_MAX)))

Definition at line 132 of file dns.h.

Enumeration Type Documentation

fr_dns_decode_fail_t

enum fr_dns_decode_fail_t

Enumerator
FR_DNS_DECODE_FAIL_NONE
FR_DNS_DECODE_FAIL_UNKNOWN_OPCODE
FR_DNS_DECODE_FAIL_MIN_LENGTH_PACKET
FR_DNS_DECODE_FAIL_MAX_LENGTH_PACKET
FR_DNS_DECODE_FAIL_UNEXPECTED
FR_DNS_DECODE_FAIL_NO_QUESTIONS
FR_DNS_DECODE_FAIL_ANSWERS_IN_QUESTION
FR_DNS_DECODE_FAIL_NS_IN_QUESTION
FR_DNS_DECODE_FAIL_INVALID_RR_LABEL
FR_DNS_DECODE_FAIL_MISSING_RR_HEADER
FR_DNS_DECODE_FAIL_MISSING_RR_LEN
FR_DNS_DECODE_FAIL_ZERO_RR_LEN
FR_DNS_DECODE_FAIL_RR_OVERFLOWS_PACKET
FR_DNS_DECODE_FAIL_TOO_MANY_RRS
FR_DNS_DECODE_FAIL_TOO_FEW_RRS
FR_DNS_DECODE_FAIL_POINTER_TO_NON_LABEL
FR_DNS_DECODE_FAIL_POINTER_OVERFLOWS_PACKET
FR_DNS_DECODE_FAIL_POINTER_TO_HEADER
FR_DNS_DECODE_FAIL_POINTER_LOOPS
FR_DNS_DECODE_FAIL_INVALID_POINTER
FR_DNS_DECODE_FAIL_LABEL_OVERFLOWS_PACKET
FR_DNS_DECODE_FAIL_LABEL_TOO_LONG
FR_DNS_DECODE_FAIL_MISSING_QD_HEADER
FR_DNS_DECODE_FAIL_MISSING_TLV_HEADER
FR_DNS_DECODE_FAIL_TLV_OVERFLOWS_RR
FR_DNS_DECODE_FAIL_TRUNCATED
FR_DNS_DECODE_FAIL_MAX

Definition at line 102 of file dns.h.

fr_dns_packet_code_t

enum fr_dns_packet_code_t

Enumerator
FR_DNS_QUERY
FR_DNS_INVERSE_QUERY
FR_DNS_STATUS
FR_DNS_NOTIFY
FR_DNS_UPDATE
FR_DNS_STATEFUL_OPERATION
FR_DNS_CODE_MAX
FR_DNS_QUERY_RESPONSE
FR_DNS_INVERSE_QUERY_RESPONSE
FR_DNS_STATUS_RESPONSE
FR_DNS_NOTIFY_RESPONSE
FR_DNS_UPDATE_RESPONSE
FR_DNS_STATEFUL_OPERATION_RESPONSE
FR_DNS_DO_NOT_RESPOND

Definition at line 83 of file dns.h.

Function Documentation

fr_dns_attr_flags()

static fr_dns_attr_flags_t const * fr_dns_attr_flags ( fr_dict_attr_t const *  da )

inlinestatic

Return DNS-specific flags for a given attribute.

Assert in debug builds when the attribute belongs to another dictionary, as the flags of one protocol say nothing about an attribute of another.

If the attribute does not carry the protocol-specific extension, then assert. Other builds log the error and return zeroed flags instead of NULL.

Definition at line 151 of file dns.h.

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fr_dns_decode()

ssize_t fr_dns_decode	(	TALLOC_CTX *	ctx,
		fr_pair_list_t *	out,
		uint8_t const *	packet,
		size_t	packet_len,
		fr_dns_ctx_t *	packet_ctx
	)

Decode a DNS packet.

Definition at line 243 of file decode.c.

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fr_dns_encode()

ssize_t fr_dns_encode	(	fr_dbuff_t *	dbuff,
		fr_pair_list_t *	vps,
		fr_dns_ctx_t *	encode_ctx
	)

Encode a DNS packet.

Definition at line 446 of file encode.c.

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fr_dns_flag_dns_label()

static bool fr_dns_flag_dns_label ( fr_dict_attr_t const *  da )

inlinestatic

Definition at line 174 of file dns.h.

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fr_dns_flag_dns_label_any()

static bool fr_dns_flag_dns_label_any ( fr_dict_attr_t const *  da )

inlinestatic

Definition at line 167 of file dns.h.

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fr_dns_flag_dns_label_uncompressed()

static bool fr_dns_flag_dns_label_uncompressed ( fr_dict_attr_t const *  da )

inlinestatic

Definition at line 179 of file dns.h.

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fr_dns_global_free()

void fr_dns_global_free

(

void

)

Definition at line 472 of file base.c.

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fr_dns_global_init()

int fr_dns_global_init

(

void

)

Resolve/cache attributes in the DNS dictionary.

Returns

• 0 on success.
• -1 on failure.

Definition at line 449 of file base.c.

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fr_dns_labels_get()

fr_dns_labels_t * fr_dns_labels_get	(	uint8_t const *	packet,
		size_t	packet_len,
		bool	init_mark
	)

Definition at line 420 of file base.c.

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fr_dns_packet_ok()

bool fr_dns_packet_ok	(	uint8_t const *	packet,
		size_t	packet_len,
		bool	query,
		fr_dns_decode_fail_t *	reason
	)

Definition at line 109 of file base.c.

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Variable Documentation

fr_dns_packet_names

char const* fr_dns_packet_names[FR_DNS_CODE_MAX]

extern

Definition at line 68 of file base.c.

fr_dns_reason_fail_table

fr_table_num_ordered_t fr_dns_reason_fail_table[]

extern

Definition at line 370 of file decode.c.

fr_dns_reason_fail_table_len

size_t fr_dns_reason_fail_table_len

extern

Definition at line 398 of file decode.c.

libfreeradius_dns_dict_protocol

fr_dict_protocol_t libfreeradius_dns_dict_protocol

extern

Definition at line 516 of file base.c.