msgparse.c File Reference

Routines for message parsing a packet buffer to a descriptive structure. More...

#include "config.h"
#include <ldns/ldns.h>
#include "util/data/msgparse.h"
#include "util/net_help.h"
#include "util/data/dname.h"
#include "util/data/packed_rrset.h"
#include "util/storage/lookup3.h"
#include "util/regional.h"

Functions
static int	smart_compare (ldns_buffer *pkt, uint8_t *dnow, uint8_t *dprfirst, uint8_t *dprlast)
	smart comparison of (compressed, valid) dnames from packet
static struct rrset_parse *	new_rrset (struct msg_parse *msg, uint8_t *dname, size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_t hash, uint32_t rrset_flags, ldns_pkt_section section, struct regional *region)
	Allocate new rrset in region, fill with data.
static int	nsec_at_apex (ldns_buffer *pkt)
	See if next rrset is nsec at zone apex.
static uint32_t	pkt_rrset_flags (ldns_buffer *pkt, uint16_t type, ldns_pkt_section sec)
	Calculate rrset flags.
hashvalue_t	pkt_hash_rrset (ldns_buffer *pkt, uint8_t *dname, uint16_t type, uint16_t dclass, uint32_t rrset_flags)
	Calculate hash value for rrset in packet.
static hashvalue_t	pkt_hash_rrset_first (ldns_buffer *pkt, uint8_t *dname)
	create partial dname hash for rrset hash
static hashvalue_t	pkt_hash_rrset_rest (hashvalue_t dname_h, uint16_t type, uint16_t dclass, uint32_t rrset_flags)
	create a rrset hash from a partial dname hash
static int	rrset_parse_equals (struct rrset_parse *p, ldns_buffer *pkt, hashvalue_t h, uint32_t rrset_flags, uint8_t *dname, size_t dnamelen, uint16_t type, uint16_t dclass)
	compare rrset_parse with data
struct rrset_parse *	msgparse_hashtable_lookup (struct msg_parse *msg, ldns_buffer *pkt, hashvalue_t h, uint32_t rrset_flags, uint8_t *dname, size_t dnamelen, uint16_t type, uint16_t dclass)
	Lookup in msg hashtable to find a rrset.
static int	pkt_rrsig_covered (ldns_buffer *pkt, uint8_t *here, uint16_t *type)
	return type networkformat that rrsig in packet covers
static int	pkt_rrsig_covered_equals (ldns_buffer *pkt, uint8_t *here, uint16_t type)
	true if covered type equals prevtype
void	msgparse_bucket_remove (struct msg_parse *msg, struct rrset_parse *rrset)
	Remove rrset from hash table.
static void	change_section (struct msg_parse *msg, struct rrset_parse *rrset, ldns_pkt_section section)
	change section of rrset from previous to current section
static int	rrset_has_sigover (ldns_buffer *pkt, struct rrset_parse *rrset, uint16_t type, int *hasother)
	see if rrset of type RRSIG contains sig over given type
static int	moveover_rrsigs (ldns_buffer *pkt, struct regional *region, struct rrset_parse *sigset, struct rrset_parse *dataset, int duplicate)
	move rrsigs from sigset to dataset
static struct rrset_parse *	change_rrsig_rrset (struct rrset_parse *sigset, struct msg_parse *msg, ldns_buffer *pkt, uint16_t datatype, uint32_t rrset_flags, int hasother, ldns_pkt_section section, struct regional *region)
	change an rrsig rrset for use as data rrset
static int	find_rrset (struct msg_parse *msg, ldns_buffer *pkt, uint8_t *dname, size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_t *hash, uint32_t *rrset_flags, uint8_t **prev_dname_first, uint8_t **prev_dname_last, size_t *prev_dnamelen, uint16_t *prev_type, uint16_t *prev_dclass, struct rrset_parse **rrset_prev, ldns_pkt_section section, struct regional *region)
	Find rrset.
static int	parse_query_section (ldns_buffer *pkt, struct msg_parse *msg)
	Parse query section.
size_t	get_rdf_size (ldns_rdf_type rdf)
	Obtain size in the packet of an rr type, that is before dname type.
static int	calc_size (ldns_buffer *pkt, uint16_t type, struct rr_parse *rr)
	calculate the size of one rr
static int	skip_ttl_rdata (ldns_buffer *pkt)
	skip rr ttl and rdata
static int	sig_is_double (ldns_buffer *pkt, struct rrset_parse *rrset, uint8_t *ttldata)
	see if RRSIG is a duplicate of another
static int	add_rr_to_rrset (struct rrset_parse *rrset, ldns_buffer *pkt, struct msg_parse *msg, struct regional *region, ldns_pkt_section section, uint16_t type)
	Add rr (from packet here) to rrset, skips rr.
static int	parse_section (ldns_buffer *pkt, struct msg_parse *msg, struct regional *region, ldns_pkt_section section, uint16_t num_rrs, size_t *num_rrsets)
	Parse packet RR section, for answer, authority and additional sections.
int	parse_packet (ldns_buffer *pkt, struct msg_parse *msg, struct regional *region)
	Parse the packet.
int	parse_extract_edns (struct msg_parse *msg, struct edns_data *edns)
	After parsing the packet, extract EDNS data from packet.
int	parse_edns_from_pkt (ldns_buffer *pkt, struct edns_data *edns)
	If EDNS data follows a query section, extract it and initialize edns struct.

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Detailed Description

Routines for message parsing a packet buffer to a descriptive structure.

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Function Documentation

hashvalue_t pkt_hash_rrset	(	ldns_buffer *	pkt,
		uint8_t *	dname,
		uint16_t	type,
		uint16_t	dclass,
		uint32_t	rrset_flags
	)

Calculate hash value for rrset in packet.

Parameters:

pkt,:	the packet.
dname,:	pointer to uncompressed dname, or compressed dname in packet.
type,:	rrset type in host order.
dclass,:	rrset class in network order.
rrset_flags,:	rrset flags (same as packed_rrset flags).

Returns:

hash value

References dname_pkt_hash().

Referenced by change_rrsig_rrset(), mark_additional_rrset(), and synth_cname_rrset().

struct rrset_parse* msgparse_hashtable_lookup	(	struct msg_parse *	msg,
		ldns_buffer *	pkt,
		hashvalue_t	h,
		uint32_t	rrset_flags,
		uint8_t *	dname,
		size_t	dnamelen,
		uint16_t	type,
		uint16_t	dclass
	)		[read]

Lookup in msg hashtable to find a rrset.

Parameters:

msg,:	with the hashtable.
pkt,:	packet for compressed names.
h,:	hash value
rrset_flags,:	flags of rrset sought for.
dname,:	name of rrset sought for.
dnamelen,:	len of dname.
type,:	rrset type, host order.
dclass,:	rrset class, network order.

Returns:

NULL or the rrset_parse if found.

References msg_parse::hashtable, PARSE_TABLE_SIZE, rrset_parse::rrset_bucket_next, and rrset_parse_equals().

Referenced by find_rrset(), and mark_additional_rrset().

void msgparse_bucket_remove	(	struct msg_parse *	msg,
		struct rrset_parse *	rrset
	)

Remove rrset from hash table.

Parameters:

msg,:	with hashtable.
rrset,:	with hash value and id info.

References rrset_parse::hash, msg_parse::hashtable, PARSE_TABLE_SIZE, and rrset_parse::rrset_bucket_next.

Referenced by change_rrsig_rrset(), and remove_rrset().

static int find_rrset	(	struct msg_parse *	msg,
		ldns_buffer *	pkt,
		uint8_t *	dname,
		size_t	dnamelen,
		uint16_t	type,
		uint16_t	dclass,
		hashvalue_t *	hash,
		uint32_t *	rrset_flags,
		uint8_t **	prev_dname_first,
		uint8_t **	prev_dname_last,
		size_t *	prev_dnamelen,
		uint16_t *	prev_type,
		uint16_t *	prev_dclass,
		struct rrset_parse **	rrset_prev,
		ldns_pkt_section	section,
		struct regional *	region
	)		[static]

Find rrset.

If equal to previous it is fast. hash if not so.

Parameters:

msg,:	the message with hash table.
pkt,:	the packet in wireformat (needed for compression ptrs).
dname,:	pointer to start of dname (compressed) in packet.
dnamelen,:	uncompressed wirefmt length of dname.
type,:	type of current rr.
dclass,:	class of current rr.
hash,:	hash value is returned if the rrset could not be found.
rrset_flags,:	is returned if the rrset could not be found.
prev_dname_first,:	dname of last seen RR. First seen dname.
prev_dname_last,:	dname of last seen RR. Last seen dname.
prev_dnamelen,:	dname len of last seen RR.
prev_type,:	type of last seen RR.
prev_dclass,:	class of last seen RR.
rrset_prev,:	last seen RRset.
section,:	the current section in the packet.
region,:	used to allocate temporary parsing data.

Returns:

0 on out of memory.

References change_rrsig_rrset(), rrset_parse::dname, msgparse_hashtable_lookup(), PACKED_RRSET_NSEC_AT_APEX, PACKED_RRSET_SOA_NEG, pkt_hash_rrset_first(), pkt_hash_rrset_rest(), pkt_rrset_flags(), pkt_rrsig_covered(), pkt_rrsig_covered_equals(), rrset_has_sigover(), smart_compare(), and rrset_parse::type.

Referenced by parse_section().

static int parse_query_section	(	ldns_buffer *	pkt,
		struct msg_parse *	msg
	)		[static]

Parse query section.

Parameters:

pkt,:	packet, position at call must be at start of query section. at end position is after query section.
msg,:	store results here.

Returns:

: 0 if OK, or rcode on error.

References log_assert, pkt_dname_len(), msg_parse::qclass, msg_parse::qdcount, msg_parse::qname, msg_parse::qname_len, and msg_parse::qtype.

Referenced by parse_packet().

size_t get_rdf_size

(

ldns_rdf_type

rdf

)

Obtain size in the packet of an rr type, that is before dname type.

Do TYPE_DNAME, and type STR, yourself. Gives size for most regular types.

Parameters:

rdf,:

the rdf type from the descriptor.

Returns:

: size in octets. 0 on failure.

References log_assert.

Referenced by analyze_rdata(), calc_size(), canonical_compare_byfield(), compress_rdata(), and rdata_copy().

static int parse_section	(	ldns_buffer *	pkt,
		struct msg_parse *	msg,
		struct regional *	region,
		ldns_pkt_section	section,
		uint16_t	num_rrs,
		size_t *	num_rrsets
	)		[static]

Parse packet RR section, for answer, authority and additional sections.

Parameters:

pkt,:	packet, position at call must be at start of section. at end position is after section.
msg,:	store results here.
region,:	how to alloc results.
section,:	section enum.
num_rrs,:	how many rrs are in the section.
num_rrsets,:	returns number of rrsets in the section.

Returns:

: 0 if OK, or rcode on error.

References add_rr_to_rrset(), rrset_parse::dname, dname_print(), find_rrset(), new_rrset(), pkt_dname_len(), pkt_rrsig_covered(), and rrset_parse::type.

Referenced by parse_packet().

int parse_packet	(	ldns_buffer *	pkt,
		struct msg_parse *	msg,
		struct regional *	region
	)

Parse the packet.

Parameters:

pkt,:	packet, position at call must be at start of packet. at end position is after packet.
msg,:	where to store results.
region,:	how to alloc results.

Returns:

: 0 if OK, or rcode on error.

References msg_parse::an_rrsets, msg_parse::ancount, msg_parse::ar_rrsets, msg_parse::arcount, msg_parse::flags, msg_parse::id, msg_parse::ns_rrsets, msg_parse::nscount, parse_query_section(), parse_section(), msg_parse::qdcount, and msg_parse::rrset_count.

Referenced by createResponse(), parse_reply(), process_response(), and reply_info_parse().

int parse_extract_edns	(	struct msg_parse *	msg,
		struct edns_data *	edns
	)

After parsing the packet, extract EDNS data from packet.

If not present this is noted in the data structure. If a parse error happens, an error code is returned.

Quirks: o ignores OPT rdata. o ignores OPT owner name. o ignores extra OPT records, except the last one in the packet.

Parameters:

msg,:	parsed message structure. Modified on exit, if EDNS was present it is removed from the additional section.
edns,:	the edns data is stored here. Does not have to be initialised.

Returns:

: 0 on success. or an RCODE on an error. RCODE formerr if OPT in wrong section, and so on.

References msg_parse::ar_rrsets, msg_parse::arcount, edns_data::bits, rrset_parse::dname, rrset_parse::dname_len, edns_data::edns_present, edns_data::edns_version, edns_data::ext_rcode, log_assert, rrset_parse::rr_count, rrset_parse::rr_first, rrset_parse::rr_last, rrset_parse::rrset_all_next, rrset_parse::rrset_class, msg_parse::rrset_count, msg_parse::rrset_first, msg_parse::rrset_last, rrset_parse::section, rr_parse::ttl_data, rrset_parse::type, and edns_data::udp_size.

Referenced by createResponse(), process_response(), and reply_info_parse().

int parse_edns_from_pkt	(	ldns_buffer *	pkt,
		struct edns_data *	edns
	)

If EDNS data follows a query section, extract it and initialize edns struct.

Parameters:

pkt,:	the packet. position at start must be right after the query section. At end, right after EDNS data or no movement if failed.
edns,:	the edns data allocated by the caller. Does not have to be initialised.

Returns:

: 0 on success, or an RCODE on error. RCODE formerr if OPT is badly formatted and so on.

References edns_data::bits, edns_data::edns_present, edns_data::edns_version, edns_data::ext_rcode, log_assert, pkt_dname_len(), and edns_data::udp_size.

Referenced by worker_handle_request().