Contains message parsing data structures. More...

#include "util/storage/lruhash.h"
#include "sldns/pkthdr.h"
#include "sldns/rrdef.h"

Data Structures
struct	msg_parse
	Data stored in scratch pad memory during parsing. More...

struct	rrset_parse
	Data stored for an rrset during parsing. More...

struct	rr_parse
	Data stored for an RR during parsing. More...

struct	edns_data
	EDNS data storage rdata is parsed in a list (has accessor functions). More...

struct	edns_option
	EDNS option. More...

Macros
#define	PARSE_TABLE_SIZE 32
	number of buckets in parse rrset hash table. More...

#define	NORR_TTL 5 /* seconds */
	Negative cache time (for entries without any RRs.)

#define	LABEL_IS_PTR(x) ( ((x)&0xc0) == 0xc0 )
	Check if label length is first octet of a compression pointer, pass u8.

#define	PTR_OFFSET(x, y) ( ((x)&0x3f)<<8 \| (y) )
	Calculate destination offset of a compression pointer. More...

#define	PTR_CREATE(offset) ((uint16_t)(0xc000 \| (offset)))
	create a compression pointer to the given offset.

#define	EDNS_RCODE_BADVERS 16 /** bad EDNS version */
	error codes, extended with EDNS, so > 15.

#define	PTR_MAX_OFFSET 0x3fff
	largest valid compression offset

Functions
size_t	get_rdf_size (sldns_rdf_type rdf)
	Obtain size in the packet of an rr type, that is before dname type. More...

int	parse_packet (struct sldns_buffer pkt, struct msg_parse msg, struct regional *region)
	Parse the packet. More...

int	parse_extract_edns_from_response_msg (struct msg_parse msg, struct edns_data edns, struct regional *region)
	After parsing the packet, extract EDNS data from packet. More...

int	skip_pkt_rrs (struct sldns_buffer *pkt, int num)
	Skip RRs from packet. More...

int	parse_edns_from_query_pkt (struct sldns_buffer pkt, struct edns_data edns, struct config_file cfg, struct comm_point c, struct comm_reply repinfo, time_t now, struct regional region)
	If EDNS data follows a query section, extract it and initialize edns struct. More...

hashvalue_type	pkt_hash_rrset (struct sldns_buffer pkt, uint8_t dname, uint16_t type, uint16_t dclass, uint32_t rrset_flags)
	Calculate hash value for rrset in packet. More...

struct rrset_parse *	msgparse_hashtable_lookup (struct msg_parse msg, struct sldns_buffer pkt, hashvalue_type 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. More...

void	msgparse_bucket_remove (struct msg_parse msg, struct rrset_parse rrset)
	Remove rrset from hash table. More...

void	log_edns_opt_list (enum verbosity_value level, const char info_str, struct edns_option list)
	Log the edns options in the edns option list. More...

int	msgparse_rrset_remove_rr (const char str, struct sldns_buffer pkt, struct rrset_parse rrset, struct rr_parse prev, struct rr_parse rr, struct sockaddr_storage addr, socklen_t addrlen)
	Remove RR from msgparse RRset. More...

Variables
time_t	MAX_TTL
	Maximum TTL that is allowed. More...

time_t	MIN_TTL
	Minimum TTL that is allowed. More...

time_t	MAX_NEG_TTL
	Maximum Negative TTL that is allowed. More...

int	SERVE_EXPIRED
	If we serve expired entries and prefetch them.

time_t	SERVE_EXPIRED_TTL
	Time to serve records after expiration.

time_t	SERVE_EXPIRED_REPLY_TTL
	TTL to use for expired records.

int	SERVE_ORIGINAL_TTL
	If we serve the original TTL or decrementing TTLs.

Detailed Description

Contains message parsing data structures.

These point back into the packet buffer.

During parsing RRSIGS are put together with the rrsets they (claim to) sign. This process works as follows: o if RRSIG follows the data rrset, it is added to the rrset rrsig list. o if no matching data rrset is found, the RRSIG becomes a new rrset. o If the data rrset later follows the RRSIG o See if the RRSIG rrset contains multiple types, and needs to have the rrsig(s) for that data type split off. o Put the data rr as data type in the rrset and rrsig in list. o RRSIGs are allowed to move to a different section. The section of the data item is used for the final rrset. o multiple signatures over an RRset are possible.

For queries of qtype=RRSIG, some special handling is needed, to avoid splitting the RRSIG in the answer section. o duplicate, not split, RRSIGs from the answer section, if qtype=RRSIG. o check for doubles in the rrsig list when adding an RRSIG to data, so that a data rrset is signed by RRSIGs with different rdata. when qtype=RRSIG. This will move the RRSIG from the answer section to sign the data further in the packet (if possible). If then after that, more RRSIGs are found that sign the data as well, doubles are removed.

Macro Definition Documentation

◆ PARSE_TABLE_SIZE

#define PARSE_TABLE_SIZE 32

number of buckets in parse rrset hash table.

Must be power of 2.

◆ PTR_OFFSET

#define PTR_OFFSET	(	x,
		y
	)	( ((x)&0x3f)<<8 \| (y) )

Calculate destination offset of a compression pointer.

pass first and second octets of the compression pointer.

Function Documentation

◆ get_rdf_size()

size_t get_rdf_size ( sldns_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 LDNS_RDF_TYPE_A, LDNS_RDF_TYPE_AAAA, LDNS_RDF_TYPE_ALG, LDNS_RDF_TYPE_CERT_ALG, LDNS_RDF_TYPE_CLASS, LDNS_RDF_TYPE_INT16, LDNS_RDF_TYPE_INT32, LDNS_RDF_TYPE_INT8, LDNS_RDF_TYPE_PERIOD, LDNS_RDF_TYPE_TIME, LDNS_RDF_TYPE_TSIGTIME, LDNS_RDF_TYPE_TYPE, and log_assert.

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

◆ parse_packet()

int parse_packet	(	struct sldns_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 sldns_buffer_remaining().

Referenced by createResponse(), and parse_reply_in_temp_region().

◆ parse_extract_edns_from_response_msg()

int parse_extract_edns_from_response_msg	(	struct msg_parse *	msg,
		struct edns_data *	edns,
		struct regional *	region
	)

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.
region	region to alloc results in (edns option contents)

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

References LDNS_RR_TYPE_OPT, msg_parse::rrset_first, and rrset_parse::type.

◆ skip_pkt_rrs()

int skip_pkt_rrs	(	sldns_buffer *	pkt,
		int	num
	)

Skip RRs from packet.

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.
num	Limit of the number of records we want to parse.

Returns: : 0 on success, 1 on failure.

Skip RRs from packet.

References skip_pkt_rr().

◆ parse_edns_from_query_pkt()

int parse_edns_from_query_pkt	(	struct sldns_buffer *	pkt,
		struct edns_data *	edns,
		struct config_file *	cfg,
		struct comm_point *	c,
		struct comm_reply *	repinfo,
		time_t	now,
		struct regional *	region
	)

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.
cfg	the configuration (with nsid value etc.)
c	commpoint to determine transport (if needed)
repinfo	commreply to determine the client address
now	current time
region	region to alloc results in (edns option contents)

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

References log_assert.

◆ pkt_hash_rrset()

hashvalue_type pkt_hash_rrset	(	struct sldns_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 rrset_parse::dname, dname_pkt_hash(), hashlittle(), and rrset_parse::type.

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

◆ msgparse_hashtable_lookup()

struct rrset_parse* msgparse_hashtable_lookup	(	struct msg_parse *	msg,
		struct sldns_buffer *	pkt,
		hashvalue_type	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.

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

Referenced by find_rrset(), and mark_additional_rrset().

◆ msgparse_bucket_remove()

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.

◆ log_edns_opt_list()

void log_edns_opt_list	(	enum verbosity_value	level,
		const char *	info_str,
		struct edns_option *	list
	)

Log the edns options in the edns option list.

Parameters

level	the verbosity level.
info_str	the informational string to be printed before the options.
list	the edns option list.

References verbosity.

◆ msgparse_rrset_remove_rr()

int msgparse_rrset_remove_rr	(	const char *	str,
		sldns_buffer *	pkt,
		struct rrset_parse *	rrset,
		struct rr_parse *	prev,
		struct rr_parse *	rr,
		struct sockaddr_storage *	addr,
		socklen_t	addrlen
	)

Remove RR from msgparse RRset.

Parameters

str	this string is used for logging if verbose. If NULL, there is no logging of the remove.
pkt	packet in buffer that is removed from. Used to log the name of the item removed.
rrset	RRset that the RR is removed from.
prev	previous RR in list, or NULL.
rr	RR that is removed.
addr	address used for logging, if verbose, or NULL then it is not used.
addrlen	length of addr, if that is not NULL.

Returns: true if rrset is entirely bad, it would then need to be removed.

Remove RR from msgparse RRset.

Variable Documentation

◆ MAX_TTL

time_t MAX_TTL

extern

Maximum TTL that is allowed.

Referenced by config_apply(), config_set_option(), parse_copy_decompress(), and parse_rr_copy().

◆ MIN_TTL

time_t MIN_TTL

extern

Minimum TTL that is allowed.

Referenced by adjust_ttl(), config_apply(), and config_set_option().

◆ MAX_NEG_TTL

time_t MAX_NEG_TTL

extern

Maximum Negative TTL that is allowed.

Referenced by config_apply(), config_set_option(), and msgparse_test().

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ PARSE_TABLE_SIZE

◆ PTR_OFFSET

Function Documentation

◆ get_rdf_size()

◆ parse_packet()

◆ parse_extract_edns_from_response_msg()

◆ skip_pkt_rrs()

◆ parse_edns_from_query_pkt()

◆ pkt_hash_rrset()

◆ msgparse_hashtable_lookup()

◆ msgparse_bucket_remove()

◆ log_edns_opt_list()

◆ msgparse_rrset_remove_rr()

Variable Documentation

◆ MAX_TTL

◆ MIN_TTL

◆ MAX_NEG_TTL