decode_header(r) -> hdr, err

Decode the 12-byte DNS header from a reader

encode_header(w, hdr, qdcount, ancount, nscount, arcount)

Encode a DNS header into a writer

decode_question(r) -> q, err

Decode a single question entry

encode_question(w, q)

Encode a single question entry

decode_rr(r) -> rr, err

Decode a single resource record

encode_rr(w, rr)

Encode a single resource record

extract_edns(additional) -> edns, filtered

Extract OPT pseudo-record from additional section into edns table

build_opt_rr(edns) -> rr

Build OPT pseudo-record RR from edns table

decode(raw_bytes) -> msg, err

Decode a raw DNS message into a structured table

Decodes a complete DNS message from a raw binary string. Returns a table with header, question, answer, authority, additional, and optionally edns fields. The OPT pseudo-record is extracted from the additional section into msg.edns.

Section counts from the header determine how many entries are parsed in each section. If any entry fails to parse, the entire decode fails with an error (strict mode).

encode(msg) -> raw_bytes

Encode a structured message table into raw DNS wire format

Encodes a complete DNS message from a structured table. Section counts are computed from the array lengths. If msg.edns is set, an OPT pseudo-record is appended to the additional section.