This file contains temporary data structures and routines to create compressed DNS messages. More...

Functions
int	reply_info_answer_encode (struct query_info qinf, struct reply_info rep, uint16_t id, uint16_t qflags, struct sldns_buffer dest, time_t timenow, int cached, struct regional region, uint16_t udpsize, struct edns_data *edns, int dnssec, int secure)
	Generate answer from reply_info. More...

int	reply_info_encode (struct query_info qinfo, struct reply_info rep, uint16_t id, uint16_t flags, struct sldns_buffer buffer, time_t timenow, struct regional region, uint16_t udpsize, int dnssec, int minimise)
	Regenerate the wireformat from the stored msg reply. More...

void	qinfo_query_encode (struct sldns_buffer pkt, struct query_info qinfo)
	Encode query packet. More...

uint16_t	calc_edns_field_size (struct edns_data *edns)
	Estimate size of EDNS record in packet. More...

uint16_t	calc_edns_option_size (struct edns_data *edns, uint16_t code)
	Calculate the size of a specific EDNS option in packet. More...

uint16_t	calc_ede_option_size (struct edns_data edns, uint16_t txt_size)
	Calculate the size of the EDE option(s) in packet. More...

void	attach_edns_record (struct sldns_buffer pkt, struct edns_data edns)
	Attach EDNS record to buffer. More...

void	error_encode (struct sldns_buffer pkt, int r, struct query_info qinfo, uint16_t qid, uint16_t qflags, struct edns_data *edns)
	Encode an error. More...

void	extended_error_encode (struct sldns_buffer pkt, uint16_t rcode, struct query_info qinfo, uint16_t qid, uint16_t qflags, uint16_t xflags, struct edns_data *edns)
	Encode an extended error. More...

Detailed Description

This file contains temporary data structures and routines to create compressed DNS messages.

Function Documentation

◆ reply_info_answer_encode()

int reply_info_answer_encode	(	struct query_info *	qinf,
		struct reply_info *	rep,
		uint16_t	id,
		uint16_t	qflags,
		struct sldns_buffer *	dest,
		time_t	timenow,
		int	cached,
		struct regional *	region,
		uint16_t	udpsize,
		struct edns_data *	edns,
		int	dnssec,
		int	secure
	)

Generate answer from reply_info.

Parameters

qinf	query information that provides query section in packet.
rep	reply to fill in.
id	id word from the query.
qflags	flags word from the query.
dest	buffer to put message into; will truncate if it does not fit.
timenow	time to subtract.
cached	set true if a cached reply (so no AA bit). set false for the first reply.
region	where to allocate temp variables (for compression).
udpsize	size of the answer, 512, from EDNS, or 64k for TCP.
edns	EDNS data included in the answer, NULL for none. or if edns_present = 0, it is not included.
dnssec	if 0 DNSSEC records are omitted from the answer.
secure	if 1, the AD bit is set in the reply.

Returns: : 0 on error (server failure).

References reply_info::authoritative, BIT_AA, BIT_AD, BIT_CD, BIT_RD, reply_info::flags, FLAGS_GET_RCODE, and query_info::local_alias.

Referenced by auth_answer_encode(), and rpz_local_encode().

◆ reply_info_encode()

int reply_info_encode	(	struct query_info *	qinfo,
		struct reply_info *	rep,
		uint16_t	id,
		uint16_t	flags,
		struct sldns_buffer *	buffer,
		time_t	timenow,
		struct regional *	region,
		uint16_t	udpsize,
		int	dnssec,
		int	minimise
	)

Regenerate the wireformat from the stored msg reply.

If the buffer is too small then the message is truncated at a whole rrset and the TC bit set, or whole rrsets are left out of the additional and the TC bit is not set.

Parameters

qinfo	query info to store.
rep	reply to store.
id	id value to store, network order.
flags	flags value to store, host order.
buffer	buffer to store the packet into.
timenow	time now, to adjust ttl values.
region	to store temporary data in.
udpsize	size of the answer, 512, from EDNS, or 64k for TCP.
dnssec	if 0 DNSSEC records are omitted from the answer.
minimise	if true, the answer is a minimal response, with authority and additional removed if possible.

Returns: : nonzero is success, or 0 on error: malloc failure (no log_err has been done).

References sldns_buffer_clear(), sldns_buffer_limit(), sldns_buffer_remaining(), and sldns_buffer_set_limit().

◆ qinfo_query_encode()

void qinfo_query_encode	(	struct sldns_buffer *	pkt,
		struct query_info *	qinfo
	)

Encode query packet.

Assumes the buffer is large enough.

Parameters

pkt	where to store the packet.
qinfo	query info.

References packed_rrset_key::dname, packed_rrset_key::dname_len, query_info::local_alias, log_assert, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, ub_packed_rrset_key::rk, local_rrset::rrset, sldns_buffer_clear(), sldns_buffer_flip(), sldns_buffer_remaining(), sldns_buffer_skip(), sldns_buffer_write(), and sldns_buffer_write_u16().

Referenced by qlist_parse_line(), and xfr_create_soa_probe_packet().

◆ calc_edns_field_size()

uint16_t calc_edns_field_size ( struct edns_data * edns )

Estimate size of EDNS record in packet.

EDNS record will be no larger.

Parameters

edns	edns data or NULL.

Returns: octets to reserve for EDNS.

References edns_data::edns_present, edns_option::next, edns_option::opt_len, edns_data::opt_list_inplace_cb_out, and edns_data::opt_list_out.

Referenced by extended_error_encode().

◆ calc_edns_option_size()

uint16_t calc_edns_option_size	(	struct edns_data *	edns,
		uint16_t	code
	)

Calculate the size of a specific EDNS option in packet.

Parameters

edns	edns data or NULL.
code	the opt code to get the size of.

Returns: octets the option will take up.

References edns_data::edns_present, edns_option::next, edns_option::opt_code, edns_option::opt_len, edns_data::opt_list_inplace_cb_out, and edns_data::opt_list_out.

◆ calc_ede_option_size()

uint16_t calc_ede_option_size	(	struct edns_data *	edns,
		uint16_t *	txt_size
	)

Calculate the size of the EDE option(s) in packet.

Also calculate seperately the size of the EXTRA-TEXT field(s) in case we can trim them to fit. In this case include any LDNS_EDE_OTHER options in their entirety since they are useless without extra text.

Parameters

edns	edns data or NULL.
txt_size	the size of the EXTRA-TEXT field(s); this includes LDNS_EDE_OTHER in their entirety since they are useless without extra text.

Returns: octets the option will take up.

References edns_data::edns_present, edns_option::next, edns_option::opt_code, and edns_data::opt_list_inplace_cb_out.

◆ attach_edns_record()

void attach_edns_record	(	struct sldns_buffer *	pkt,
		struct edns_data *	edns
	)

Attach EDNS record to buffer.

Buffer has complete packet. There must be enough room left for the EDNS record.

Parameters

pkt	packet added to.
edns	if NULL or present=0, nothing is added to the packet.

References edns_data::edns_present.

◆ error_encode()

void error_encode	(	struct sldns_buffer *	pkt,
		int	r,
		struct query_info *	qinfo,
		uint16_t	qid,
		uint16_t	qflags,
		struct edns_data *	edns
	)

Encode an error.

With QR and RA set.

Parameters

pkt	where to store the packet.
r	RCODE value to encode (may contain extra flags).
qinfo	if not NULL, the query is included.
qid	query ID to set in packet. network order.
qflags	original query flags (to copy RD and CD bits). host order.
edns	if not NULL, this is the query edns info, and an edns reply is attached. Only attached if EDNS record fits reply.

References extended_error_encode().

Referenced by auth_answer_encode(), auth_error_encode(), libworker_bg_done_cb(), and rpz_local_encode().

◆ extended_error_encode()

void extended_error_encode	(	struct sldns_buffer *	pkt,
		uint16_t	rcode,
		struct query_info *	qinfo,
		uint16_t	qid,
		uint16_t	qflags,
		uint16_t	xflags,
		struct edns_data *	edns
	)

Encode an extended error.

With QR and RA set.

Parameters

pkt	where to store the packet.
rcode	Extended RCODE value to encode.
qinfo	if not NULL, the query is included.
qid	query ID to set in packet. network order.
qflags	original query flags (to copy RD and CD bits). host order.
xflags	extra flags to set (such as for example BIT_AA and/or BIT_TC)
edns	if not NULL, this is the query edns info, and an edns reply is attached. Only attached if EDNS record fits reply. Without edns extended errors (i.e. > 15) will not be conveyed.

References BIT_CD, BIT_QR, BIT_RA, BIT_RD, edns_data::bits, calc_edns_field_size(), packed_rrset_key::dname, packed_rrset_key::dname_len, EDNS_ADVERTISED_SIZE, EDNS_ADVERTISED_VERSION, EDNS_DO, edns_opt_list_remove(), edns_data::edns_version, edns_data::ext_rcode, query_info::local_alias, edns_data::opt_list_inplace_cb_out, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, ub_packed_rrset_key::rk, local_rrset::rrset, sldns_buffer_clear(), sldns_buffer_current(), sldns_buffer_flip(), sldns_buffer_limit(), sldns_buffer_skip(), sldns_buffer_write(), sldns_buffer_write_u16(), and edns_data::udp_size.

Referenced by error_encode().

Functions

Detailed Description

Function Documentation

◆ reply_info_answer_encode()

◆ reply_info_encode()

◆ qinfo_query_encode()

◆ calc_edns_field_size()

◆ calc_edns_option_size()

◆ calc_ede_option_size()

◆ attach_edns_record()

◆ error_encode()

◆ extended_error_encode()