msgencode.h File Reference

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, ldns_buffer *dest, uint32_t timenow, int cached, struct regional *region, uint16_t udpsize, struct edns_data *edns, int dnssec, int secure)
	Generate answer from reply_info.
int	reply_info_encode (struct query_info *qinfo, struct reply_info *rep, uint16_t id, uint16_t flags, ldns_buffer *buffer, uint32_t timenow, struct regional *region, uint16_t udpsize, int dnssec)
	Regenerate the wireformat from the stored msg reply.
void	qinfo_query_encode (ldns_buffer *pkt, struct query_info *qinfo)
	Encode query packet.
uint16_t	calc_edns_field_size (struct edns_data *edns)
	Estimate size of EDNS record in packet.
void	attach_edns_record (ldns_buffer *pkt, struct edns_data *edns)
	Attach EDNS record to buffer.
void	error_encode (ldns_buffer *pkt, int r, struct query_info *qinfo, uint16_t qid, uint16_t qflags, struct edns_data *edns)
	Encode an error.

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Detailed Description

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

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Function Documentation

int reply_info_answer_encode	(	struct query_info *	qinf,
		struct reply_info *	rep,
		uint16_t	id,
		uint16_t	qflags,
		ldns_buffer *	dest,
		uint32_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 attach_edns_record(), reply_info::authoritative, BIT_AA, BIT_AD, BIT_CD, BIT_QR, BIT_RD, calc_edns_field_size(), reply_info::flags, log_assert, log_err(), and reply_info_encode().

Referenced by answer_from_cache(), answer_norec_from_cache(), local_encode(), mesh_do_callback(), and mesh_send_reply().

int reply_info_encode	(	struct query_info *	qinfo,
		struct reply_info *	rep,
		uint16_t	id,
		uint16_t	flags,
		ldns_buffer *	buffer,
		uint32_t	timenow,
		struct regional *	region,
		uint16_t	udpsize,
		int	dnssec
	)

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.

Returns:

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

References reply_info::an_numrrsets, reply_info::ar_numrrsets, insert_query(), insert_section(), reply_info::ns_numrrsets, reply_info::qdcount, query_info::qtype, RETVAL_OK, and RETVAL_TRUNC.

Referenced by log_dns_msg(), perf_encode(), reply_info_answer_encode(), and testpkt().

void qinfo_query_encode	(	ldns_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 log_assert, query_info::qclass, query_info::qname, query_info::qname_len, and query_info::qtype.

Referenced by qlist_parse_line(), and write_q().

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.

Referenced by error_encode(), reply_info_answer_encode(), and testpkt().

void attach_edns_record	(	ldns_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::bits, edns_data::edns_present, edns_data::edns_version, edns_data::ext_rcode, and edns_data::udp_size.

Referenced by chaos_replystr(), error_encode(), outnet_serviced_query(), perf_encode(), qlist_parse_line(), reply_info_answer_encode(), serviced_encode(), testpkt(), and worker_handle_request().

void error_encode	(	ldns_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.
	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 attach_edns_record(), BIT_CD, BIT_QR, BIT_RA, BIT_RD, edns_data::bits, calc_edns_field_size(), EDNS_ADVERTISED_SIZE, EDNS_ADVERTISED_VERSION, EDNS_DO, edns_data::edns_version, edns_data::ext_rcode, query_info::qclass, query_info::qname, query_info::qname_len, query_info::qtype, and edns_data::udp_size.

Referenced by answer_from_cache(), answer_norec_from_cache(), libworker_bg_done_cb(), local_encode(), lz_zone_answer(), mesh_new_client(), mesh_send_reply(), and worker_handle_request().