dname.h File Reference

This file contains functions to deal with domain names (dnames). More...

#include "util/storage/lruhash.h"

Defines

#define MAX_COMPRESS_PTRS   256
 max number of compression ptrs to follow

Functions

size_t query_dname_len (ldns_buffer *query)
 Determine length of dname in buffer, no compression ptrs allowed,.
size_t dname_valid (uint8_t *dname, size_t len)
 Determine if dname in memory is correct.
void query_dname_tolower (uint8_t *dname)
 lowercase query dname
void pkt_dname_tolower (ldns_buffer *pkt, uint8_t *dname)
 lowercase pkt dname (follows compression pointers)
int query_dname_compare (uint8_t *d1, uint8_t *d2)
 Compare query dnames (uncompressed storage).
size_t pkt_dname_len (ldns_buffer *pkt)
 Determine correct, compressed, dname present in packet.
int dname_pkt_compare (ldns_buffer *pkt, uint8_t *d1, uint8_t *d2)
 Compare dnames in packet (compressed).
hashvalue_t dname_query_hash (uint8_t *dname, hashvalue_t h)
 Hash dname, label by label, lowercasing, into hashvalue.
hashvalue_t dname_pkt_hash (ldns_buffer *pkt, uint8_t *dname, hashvalue_t h)
 Hash dname, label by label, lowercasing, into hashvalue.
void dname_pkt_copy (ldns_buffer *pkt, uint8_t *to, uint8_t *dname)
 Copy over a valid dname and decompress it.
int dname_buffer_write (ldns_buffer *pkt, uint8_t *dname)
 Copy over a valid dname to a packet.
int dname_count_labels (uint8_t *dname)
 Count the number of labels in an uncompressed dname in memory.
int dname_count_size_labels (uint8_t *dname, size_t *size)
 Count labels and dname length both, for uncompressed dname in memory.
int dname_lab_cmp (uint8_t *d1, int labs1, uint8_t *d2, int labs2, int *mlabs)
 Compare dnames, sorted not canonical, but by label.
int dname_strict_subdomain (uint8_t *d1, int labs1, uint8_t *d2, int labs2)
 See if domain name d1 is a strict subdomain of d2.
int dname_strict_subdomain_c (uint8_t *d1, uint8_t *d2)
 Like dname_strict_subdomain but counts labels.
int dname_subdomain_c (uint8_t *d1, uint8_t *d2)
 Counts labels.
void dname_print (FILE *out, ldns_buffer *pkt, uint8_t *dname)
 Debug helper.
void dname_str (uint8_t *dname, char *str)
 Debug helper.
int dname_is_root (uint8_t *dname)
 Returns true if the uncompressed wireformat dname is the root ".".
void dname_remove_label (uint8_t **dname, size_t *len)
 Snip off first label from a dname, returning the parent zone.
void dname_remove_labels (uint8_t **dname, size_t *len, int n)
 Snip off first N labels from a dname, returning the parent zone.
int dname_signame_label_count (uint8_t *dname)
 Count labels for the RRSIG signature label field.
int dname_is_wild (uint8_t *dname)
 Return true if the label is a wildcard, *.example.com.
int dname_canon_lab_cmp (uint8_t *d1, int labs1, uint8_t *d2, int labs2, int *mlabs)
 Compare dnames, Canonical in rfc4034 sense, but by label.
int dname_canonical_compare (uint8_t *d1, uint8_t *d2)
 Canonical dname compare.
uint8_t * dname_get_shared_topdomain (uint8_t *d1, uint8_t *d2)
 Get the shared topdomain between two names.

Detailed Description

This file contains functions to deal with domain names (dnames).

Some of the functions deal with domain names as a wireformat buffer, with a length.


Function Documentation

size_t query_dname_len ( ldns_buffer *  query  ) 

Determine length of dname in buffer, no compression ptrs allowed,.

Parameters:
query,: the ldns buffer, current position at start of dname. at end, position is at end of the dname.
Returns:
: 0 on parse failure, or length including ending 0 of dname.

Referenced by chaos_replystr(), dname_test_qdl(), and query_info_parse().

size_t dname_valid ( uint8_t *  dname,
size_t  len 
)

Determine if dname in memory is correct.

no compression ptrs allowed.

Parameters:
dname,: where dname starts in memory.
len,: dname is not allowed to exceed this length (i.e. of allocation).
Returns:
length of dname if dname is ok, 0 on a parse error.

Referenced by canonicalize_rdata(), delegpt_rrset_add_ns(), dname_test_valid(), dnskey_verify_rrset_sig(), get_cname_target(), nsec_get_next(), nsec_has_type(), rrsig_get_signer(), sanitize_nsec_is_overreach(), and wipeout().

void pkt_dname_tolower ( ldns_buffer *  pkt,
uint8_t *  dname 
)

lowercase pkt dname (follows compression pointers)

Parameters:
pkt,: the packet, used to follow compression pointers. Position is unchanged.
dname,: start of dname in packet.

References LABEL_IS_PTR, and PTR_OFFSET.

Referenced by serviced_callbacks().

int query_dname_compare ( uint8_t *  d1,
uint8_t *  d2 
)

Compare query dnames (uncompressed storage).

The Dnames passed do not have to be lowercased, comparison routine does this.

This routine is special, in that the comparison that it does corresponds with the canonical comparison needed when comparing dnames inside rdata for RR types that need canonicalization. That means that the first byte that is smaller (possibly after lowercasing) makes an RR smaller, or the shortest name makes an RR smaller.

This routine does not compute the canonical order needed for NSEC processing.

Dnames have to be valid format.

Parameters:
d1,: dname to compare
d2,: dname to compare
Returns:
: -1, 0, or +1 depending on comparison results. Sort order is first difference found. not the canonical ordering.
size_t pkt_dname_len ( ldns_buffer *  pkt  ) 

Determine correct, compressed, dname present in packet.

Checks for parse errors.

Parameters:
pkt,: packet to read from (from current start position).
Returns:
: 0 on parse error. At exit the position is right after the (compressed) dname. Compression pointers are followed and checked for loops. The uncompressed wireformat length is returned.

References LABEL_IS_PTR, MAX_COMPRESS_PTRS, and PTR_OFFSET.

Referenced by analyze_dname(), calc_size(), dname_test_pkt_dname_len(), get_additional_name(), nsec_at_apex(), parse_edns_from_pkt(), parse_query_section(), parse_section(), and rdata_copy().

int dname_pkt_compare ( ldns_buffer *  pkt,
uint8_t *  d1,
uint8_t *  d2 
)

Compare dnames in packet (compressed).

Dnames must be valid. routine performs lowercasing, so the packet casing is preserved.

Parameters:
pkt,: packet, used to resolve compression pointers.
d1,: dname to compare
d2,: dname to compare
Returns:
: -1, 0, or +1 depending on comparison results. Sort order is first difference found. not the canonical ordering.

References LABEL_IS_PTR, log_assert, and PTR_OFFSET.

Referenced by rrset_parse_equals(), scrub_message(), scrub_normalize(), scrub_sanitize(), and smart_compare().

hashvalue_t dname_query_hash ( uint8_t *  dname,
hashvalue_t  h 
)

Hash dname, label by label, lowercasing, into hashvalue.

Dname in query format (not compressed).

Parameters:
dname,: dname to hash.
h,: initial hash value.
Returns:
: result hash value.

References log_assert.

Referenced by hash_lameness(), key_entry_hash(), query_info_hash(), and rrset_key_hash().

hashvalue_t dname_pkt_hash ( ldns_buffer *  pkt,
uint8_t *  dname,
hashvalue_t  h 
)

Hash dname, label by label, lowercasing, into hashvalue.

Dname in pkt format (compressed).

Parameters:
pkt,: packet, for resolving compression pointers.
dname,: dname to hash, pointer to the pkt buffer. Must be valid format. No loops, etc.
h,: initial hash value.
Returns:
: result hash value. Result is the same as dname_query_hash, even if compression is used.

References LABEL_IS_PTR, log_assert, and PTR_OFFSET.

Referenced by pkt_hash_rrset(), and pkt_hash_rrset_first().

void dname_pkt_copy ( ldns_buffer *  pkt,
uint8_t *  to,
uint8_t *  dname 
)

Copy over a valid dname and decompress it.

Parameters:
pkt,: packet to resolve compression pointers.
to,: buffer of size from pkt_len function to hold result.
dname,: pointer into packet where dname starts.

References LABEL_IS_PTR, log_assert, log_err(), and PTR_OFFSET.

Referenced by parse_copy_decompress_rrset(), parse_create_qinfo(), pkt_strict_sub(), pkt_sub(), priv_lookup_name(), rdata_copy(), remove_rrset(), sub_of_pkt(), synth_cname(), and synth_cname_rrset().

int dname_buffer_write ( ldns_buffer *  pkt,
uint8_t *  dname 
)

Copy over a valid dname to a packet.

Parameters:
pkt,: packet to copy to.
dname,: dname to copy.
Returns:
: 0 if not enough space in buffer.

Referenced by compress_any_dname().

int dname_count_labels ( uint8_t *  dname  ) 
int dname_count_size_labels ( uint8_t *  dname,
size_t *  size 
)

Count labels and dname length both, for uncompressed dname in memory.

Parameters:
dname,: pointer to uncompressed dname.
size,: length of dname, including root label.
Returns:
: count of labels, including root label, "com." has 2 labels.

Referenced by anchor_store_new_key(), compress_rdata(), delegpt_add_ns(), delegpt_set_name(), dname_test_count_size_labels(), forwards_delete_zone(), forwards_lookup(), hints_lookup_stub(), local_zones_add_RR(), lz_enter_rr_into_zone(), lz_enter_rr_str(), lz_setup_implicit(), make_stub_holes(), nsec3_prove_wildcard(), parse_arg_name(), parse_dname(), parse_id(), priv_lookup_name(), read_names(), val_find_best_signer(), wipeout(), and write_q().

int dname_lab_cmp ( uint8_t *  d1,
int  labs1,
uint8_t *  d2,
int  labs2,
int *  mlabs 
)

Compare dnames, sorted not canonical, but by label.

Such that zone contents follows zone apex.

Parameters:
d1,: first dname. pointer to uncompressed wireformat.
labs1,: number of labels in first dname.
d2,: second dname. pointer to uncompressed wireformat.
labs2,: number of labels in second dname.
mlabs,: number of labels that matched exactly (the shared topdomain).
Returns:
: 0 for equal, -1 smaller, or +1 d1 larger than d2.

References log_assert.

Referenced by anchor_cmp(), anchors_init_parents_locked(), anchors_lookup(), compress_tree_search(), dname_get_shared_topdomain(), dname_strict_subdomain(), dname_subdomain_c(), dname_test_dname_lab_cmp(), forwards_lookup(), fwd_cmp(), fwd_init_parents(), init_parents(), local_zone_cmp(), local_zones_lookup(), lz_setup_implicit(), name_tree_compare(), name_tree_init_parents(), name_tree_lookup(), neg_closest_data_parent(), neg_closest_zone_parent(), and val_find_best_signer().

int dname_strict_subdomain ( uint8_t *  d1,
int  labs1,
uint8_t *  d2,
int  labs2 
)

See if domain name d1 is a strict subdomain of d2.

That is a subdomain, but not equal.

Parameters:
d1,: domain name, uncompressed wireformat
labs1,: number of labels in d1, including root label.
d2,: domain name, uncompressed wireformat
labs2,: number of labels in d2, including root label.
Returns:
true if d1 is a subdomain of d2, but not equal to d2.

References dname_lab_cmp().

Referenced by dname_strict_subdomain_c(), dname_test_strict_subdomain(), hints_lookup_stub(), is_terminal(), iter_msg_from_zone(), and set_kiddo_parents().

int dname_strict_subdomain_c ( uint8_t *  d1,
uint8_t *  d2 
)

Like dname_strict_subdomain but counts labels.

Parameters:
d1,: domain name, uncompressed wireformat
d2,: domain name, uncompressed wireformat
Returns:
true if d1 is a subdomain of d2, but not equal to d2.

References dname_count_labels(), and dname_strict_subdomain().

Referenced by handle_cname_response(), nsec_proves_nodata(), pkt_strict_sub(), processInit(), processQueryResponse(), response_type_from_server(), val_nsec_check_dlv(), and val_nsec_proves_name_error().

int dname_subdomain_c ( uint8_t *  d1,
uint8_t *  d2 
)
void dname_print ( FILE *  out,
ldns_buffer *  pkt,
uint8_t *  dname 
)

Debug helper.

Print wireformat dname to output.

Parameters:
out,: like stdout or a file.
pkt,: if not NULL, the packet for resolving compression ptrs.
dname,: pointer to (start of) dname.

References LABEL_IS_PTR, and PTR_OFFSET.

Referenced by analyze_dname(), parse_section(), and print_neg_cache().

void dname_str ( uint8_t *  dname,
char *  str 
)

Debug helper.

Print dname to given string buffer (string buffer must be at least 255 chars + 1 for the 0, in printable form. This may lose information (? for nonprintable characters, or & if the name is too long, # for a bad label length).

Parameters:
dname,: uncompressed wireformat.
str,: buffer of 255+1 length.

Referenced by anchors_assemble_rrsets(), autr_debug_print_tp(), delegpt_log(), do_dump_requestlist(), do_list_local_zones(), errinf_dname(), errinf_rrset(), errinf_to_str(), fill_canon(), get_mesh_status(), log_name_addr(), log_nametypeclass(), print_deleg_lookup(), print_neg_cache(), serviced_perturb_qname(), and ssl_print_name_dp().

int dname_is_root ( uint8_t *  dname  ) 

Returns true if the uncompressed wireformat dname is the root ".".

Parameters:
dname,: the dname to check
Returns:
true if ".", false if not.

References LABEL_IS_PTR, and log_assert.

Referenced by calc_data_need(), calc_zone_need(), check_data(), check_zone_invariants(), del_empty_term(), dname_test_isroot(), forward_request(), forwards_next_root(), key_cache_obtain(), name_tree_next_root(), prime_stub(), print_deleg_lookup(), and processInitRequest().

void dname_remove_label ( uint8_t **  dname,
size_t *  len 
)
void dname_remove_labels ( uint8_t **  dname,
size_t *  len,
int  n 
)

Snip off first N labels from a dname, returning the parent zone.

Parameters:
dname,: from what to strip off. uncompressed wireformat.
len,: length, adjusted to become less.
n,: number of labels to strip off (from the left). if 0, nothing happens.
Returns:
stripped off, or "." if input was ".".

References dname_remove_label().

Referenced by dlv_topdomain(), dname_get_shared_topdomain(), lz_setup_implicit(), next_closer(), processFindKey(), val_nsec_proves_no_wc(), and val_rrset_wildcard().

int dname_signame_label_count ( uint8_t *  dname  ) 

Count labels for the RRSIG signature label field.

Like a normal labelcount, but "*" wildcard and "." root are not counted.

Parameters:
dname,: valid uncompressed wireformat.

Referenced by dname_test_sigcount(), dnskey_verify_rrset_sig(), and insert_can_owner().

int dname_is_wild ( uint8_t *  dname  ) 

Return true if the label is a wildcard, *.example.com.

Parameters:
dname,: valid uncompressed wireformat.
Returns:
true if wildcard, or false.

Referenced by dname_test_iswild(), nsec_proves_nodata(), and val_nsec_prove_nodata_dsreply().

int dname_canon_lab_cmp ( uint8_t *  d1,
int  labs1,
uint8_t *  d2,
int  labs2,
int *  mlabs 
)

Compare dnames, Canonical in rfc4034 sense, but by label.

Such that zone contents follows zone apex.

Parameters:
d1,: first dname. pointer to uncompressed wireformat.
labs1,: number of labels in first dname.
d2,: second dname. pointer to uncompressed wireformat.
labs2,: number of labels in second dname.
mlabs,: number of labels that matched exactly (the shared topdomain).
Returns:
: 0 for equal, -1 smaller, or +1 d1 larger than d2.

References log_assert, and memcanoncmp().

Referenced by dname_canonical_compare(), local_data_cmp(), val_neg_data_compare(), val_neg_zone_compare(), and wipeout().

int dname_canonical_compare ( uint8_t *  d1,
uint8_t *  d2 
)

Canonical dname compare.

Takes care of counting labels. Per rfc 4034 canonical order.

Parameters:
d1,: first dname. pointer to uncompressed wireformat.
d2,: second dname. pointer to uncompressed wireformat.
Returns:
: 0 for equal, -1 smaller, or +1 d1 larger than d2.

References dname_canon_lab_cmp(), and dname_count_labels().

Referenced by dname_test_canoncmp(), nsec_proves_nodata(), val_nsec_check_dlv(), and val_nsec_proves_name_error().

uint8_t* dname_get_shared_topdomain ( uint8_t *  d1,
uint8_t *  d2 
)

Get the shared topdomain between two names.

Root "." or longer.

Parameters:
d1,: first dname. pointer to uncompressed wireformat.
d2,: second dname. pointer to uncompressed wireformat.
Returns:
pointer to shared topdomain. Ptr to a part of d1.

References dname_count_labels(), dname_lab_cmp(), and dname_remove_labels().

Referenced by dlv_topdomain(), dname_test_topdomain(), and nsec_closest_encloser().

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