decode.c File Reference

Functions to decode DNS packets. More...

#include <freeradius-devel/io/test_point.h>
#include <freeradius-devel/util/dns.h>
#include <freeradius-devel/util/proto.h>
#include <freeradius-devel/util/struct.h>
#include "dns.h"
#include "attrs.h"

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Macros
#define	DNS_GET_OPTION_LEN(_x)   fr_nbo_to_uint16((_x) + 2)
#define	DNS_GET_OPTION_NUM(_x)   fr_nbo_to_uint16(_x)

Functions
static ssize_t	decode_option (TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *parent, uint8_t const *data, size_t const data_len, void *decode_ctx)
static ssize_t	decode_proto (TALLOC_CTX *ctx, fr_pair_list_t *out, uint8_t const *data, size_t data_len, void *proto_ctx)
static ssize_t	decode_record (TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *attr, uint8_t const *rr, uint8_t const *end, fr_dns_ctx_t *packet_ctx, uint8_t const *counter)
static ssize_t	decode_rr (TALLOC_CTX *ctx, fr_pair_list_t *out, UNUSED fr_dict_attr_t const *parent, uint8_t const *data, size_t data_len, void *decode_ctx)
	Decode DNS RR. More...
static int	decode_test_ctx (void **out, TALLOC_CTX *ctx)
static ssize_t	decode_tlv_trampoline (TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *parent, uint8_t const *data, size_t const data_len, void *decode_ctx)
static ssize_t	decode_value (TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *parent, uint8_t const *data, size_t const data_len, void *decode_ctx)
static ssize_t	decode_value_trampoline (TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *parent, uint8_t const *data, size_t const data_len, void *decode_ctx)
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. More...

Variables
fr_test_point_pair_decode_t	dns_tp_decode_pair
fr_test_point_proto_decode_t	dns_tp_decode_proto
fr_table_num_ordered_t	fr_dns_reason_fail_table []
size_t	fr_dns_reason_fail_table_len = NUM_ELEMENTS(fr_dns_reason_fail_table)

Detailed Description

Functions to decode DNS packets.

Id

218693a62d08117aaddcd56c87bfdaa4cef4860f

Author

Alan DeKok (aland.nosp@m.@fre.nosp@m.eradi.nosp@m.us.o.nosp@m.rg)

Copyright

2021 The FreeRADIUS server project

2021 NetworkRADIUS SARL (legal.nosp@m.@net.nosp@m.workr.nosp@m.adiu.nosp@m.s.com)

Definition in file decode.c.

Macro Definition Documentation

DNS_GET_OPTION_LEN

#define DNS_GET_OPTION_LEN

(

_x

)

fr_nbo_to_uint16((_x) + 2)

Definition at line 172 of file decode.c.

DNS_GET_OPTION_NUM

#define DNS_GET_OPTION_NUM

(

_x

)

fr_nbo_to_uint16(_x)

Definition at line 171 of file decode.c.

Function Documentation

decode_option()

static ssize_t decode_option ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, fr_dict_attr_t const *  parent, uint8_t const *  data, size_t const  data_len, void *  decode_ctx  )

static

Definition at line 174 of file decode.c.

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decode_proto()

static ssize_t decode_proto ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, uint8_t const *  data, size_t  data_len, void *  proto_ctx  )

static

Definition at line 415 of file decode.c.

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decode_record()

static ssize_t decode_record ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, fr_dict_attr_t const *  attr, uint8_t const *  rr, uint8_t const *  end, fr_dns_ctx_t *  packet_ctx, uint8_t const *  counter  )

static

Definition at line 230 of file decode.c.

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decode_rr()

static ssize_t decode_rr ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, UNUSED fr_dict_attr_t const *  parent, uint8_t const *  data, size_t  data_len, void *  decode_ctx  )

static

Decode DNS RR.

Parameters

[in]	ctx	context to alloc new attributes in.
[in,out]	out	Where to write the decoded options.
[in]	parent	to lookup attributes in.
[in]	data	to parse.
[in]	data_len	of data to parse.
[in]	decode_ctx	Unused.

Definition at line 338 of file decode.c.

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decode_test_ctx()

static int decode_test_ctx ( void **  out, TALLOC_CTX *  ctx  )

static

Definition at line 375 of file decode.c.

decode_tlv_trampoline()

static ssize_t decode_tlv_trampoline ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, fr_dict_attr_t const *  parent, uint8_t const *  data, size_t const  data_len, void *  decode_ctx  )

static

Definition at line 44 of file decode.c.

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decode_value()

static ssize_t decode_value ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, fr_dict_attr_t const *  parent, uint8_t const *  data, size_t const  data_len, void *  decode_ctx  )

static

Definition at line 66 of file decode.c.

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decode_value_trampoline()

static ssize_t decode_value_trampoline ( TALLOC_CTX *  ctx, fr_pair_list_t *  out, fr_dict_attr_t const *  parent, uint8_t const *  data, size_t const  data_len, void *  decode_ctx  )

static

Definition at line 52 of file decode.c.

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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 265 of file decode.c.

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Variable Documentation

dns_tp_decode_pair

fr_test_point_pair_decode_t dns_tp_decode_pair

Initial value:

= {
        .test_ctx       = decode_test_ctx,
        .func           = decode_rr
}

Definition at line 448 of file decode.c.

dns_tp_decode_proto

fr_test_point_proto_decode_t dns_tp_decode_proto

Initial value:

= {
        .test_ctx       = decode_test_ctx,
        .func           = decode_proto
}

Definition at line 454 of file decode.c.

fr_dns_reason_fail_table

fr_table_num_ordered_t fr_dns_reason_fail_table[]

Initial value:

= {
        { L("none"),                                            FR_DNS_DECODE_FAIL_NONE         },
        { L("packet is smaller than DNS header"),               FR_DNS_DECODE_FAIL_MIN_LENGTH_PACKET    },
        { L("packet is larger than 65535"),                     FR_DNS_DECODE_FAIL_MAX_LENGTH_PACKET    },
        { L("expected query / answer, got answer / query"),     FR_DNS_DECODE_FAIL_UNEXPECTED           },
        { L("no 'questions' in query packet"),                  FR_DNS_DECODE_FAIL_NO_QUESTIONS },
        { L("unexprected answers in query packet"),             FR_DNS_DECODE_FAIL_ANSWERS_IN_QUESTION  },
        { L("unexpected NS records in query packet"),           FR_DNS_DECODE_FAIL_NS_IN_QUESTION       },
        { L("invalid label for resource record"),               FR_DNS_DECODE_FAIL_INVALID_RR_LABEL     },
        { L("missing resource record header"),                  FR_DNS_DECODE_FAIL_MISSING_RR_HEADER    },
        { L("missing resource record length field"),            FR_DNS_DECODE_FAIL_MISSING_RR_LEN       },
        { L("resource record length field is zero"),            FR_DNS_DECODE_FAIL_ZERO_RR_LEN  },
        { L("resource record length overflows the packet"),     FR_DNS_DECODE_FAIL_RR_OVERFLOWS_PACKET  },
        { L("more resource records than indicated in header"),  FR_DNS_DECODE_FAIL_TOO_MANY_RRS },
        { L("fewer resource records than indicated in header"), FR_DNS_DECODE_FAIL_TOO_FEW_RRS          },
        { L("pointer overflows packet"),                        FR_DNS_DECODE_FAIL_POINTER_OVERFLOWS_PACKET     },
        { L("pointer points to packet header"),                 FR_DNS_DECODE_FAIL_POINTER_TO_HEADER            },
        { L("pointer does not point to a label"),               FR_DNS_DECODE_FAIL_POINTER_TO_NON_LABEL         },
        { L("pointer creates a loop"),                          FR_DNS_DECODE_FAIL_POINTER_LOOPS                },
        { L("invalid pointer"),                                 FR_DNS_DECODE_FAIL_INVALID_POINTER              },
        { L("label overflows the packet"),                      FR_DNS_DECODE_FAIL_LABEL_OVERFLOWS_PACKET       },
        { L("too many characters in label"),                    FR_DNS_DECODE_FAIL_LABEL_TOO_LONG               },
        { L("query record header is missing"),                  FR_DNS_DECODE_FAIL_MISSING_QD_HEADER            },
        { L("missing TLV header in OPT RR"),                    FR_DNS_DECODE_FAIL_MISSING_TLV_HEADER           },
        { L("TLV overflows enclosing RR"),                      FR_DNS_DECODE_FAIL_TLV_OVERFLOWS_RR             },
}

Definition at line 387 of file decode.c.

fr_dns_reason_fail_table_len

size_t fr_dns_reason_fail_table_len = NUM_ELEMENTS(fr_dns_reason_fail_table)

Definition at line 413 of file decode.c.