feat(udp): speak WSJT-X to Logger32, and lighten Sahara

"sent 1153 bytes to 127.0.0.1:2250" and nothing in Logger32. Both true: the line the operator screenshotted is titled "Setup additional WSJT/JTDX UDP sockets", and those receivers take UDP LOGGING PACKETS — the WSJT-X v2 protocol. A bare ADIF record posted to them is dropped without a word. So there is a new outbound service rather than a change to the existing one: "WSJT-X logged QSO (Logger32)" sends the same ADIF wrapped in a Logged ADIF datagram (magic 0xadbccbda, schema 2, type 12), defaulting to port 2250. The plain-text row stays for JTAlert/GridTracker-style receivers, because the two really are different wire formats and one row cannot be both. The id string is "OpsLog", not "WSJT-X": a receiver uses it to tell instances apart, and impersonating the real thing would make a second WSJT-X indistinguishable from us. Tested both ways — the header byte for byte, and a round trip back through our own ParseWSJT, since that is the same decoding every receiver applies. Sahara moves to the parchment an operator asked for: page #e6ded0, panels #f3eee2, toolbars #ded5c4, terracotta #c4501e on the buttons and the focus ring. Lighter and less saturated than the deep sand it was.
2026-08-14 17:51:31 +02:00
parent c5c9d355ec
commit d95c998081
10 changed files with 165 additions and 32 deletions
@@ -0,0 +1,50 @@
+package udp
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+// Sending WSJT-X UDP messages, as opposed to parsing them (wsjt.go).
+//
+// This exists for Logger32, and for anything else that listens on the WSJT-X
+// interface rather than for plain text. Logger32's "additional WSJT/JTDX UDP
+// sockets" receivers — ports 2250, 2251, 2252 — are documented as receiving
+// "UDP logging packets": they speak the WSJT-X v2 protocol, and a raw ADIF
+// record posted to them is discarded without a word.
+//
+// That is a real distinction and not a detail: an operator can watch OpsLog
+// report "sent 1153 bytes to 127.0.0.1:2250" and see nothing whatsoever appear
+// in Logger32, because both statements are true.
+
+// buildQString encodes a Qt QString/QByteArray as QDataStream writes it: a
+// big-endian int32 length followed by the UTF-8 bytes. A negative length means
+// null, which is not what we ever want here — an empty string is length 0.
+func buildQString(s string) []byte {
+	out := make([]byte, 4, 4+len(s))
+	binary.BigEndian.PutUint32(out, uint32(len(s)))
+	return append(out, s...)
+}
+
+// BuildWSJTLoggedADIF frames a WSJT-X "Logged ADIF" datagram (message type 12).
+//
+//	uint32  magic   0xadbccbda
+//	uint32  schema  2
+//	uint32  type    12
+//	QString id      the sending program's name
+//	QString adif    the ADIF record
+//
+// id matters more than it looks: a receiver uses it to tell instances apart, and
+// some show it in their log. "OpsLog" is honest — pretending to be WSJT-X would
+// make a second instance of the real thing indistinguishable from us.
+func BuildWSJTLoggedADIF(id, adif string) []byte {
+	var b bytes.Buffer
+	var hdr [12]byte
+	binary.BigEndian.PutUint32(hdr[0:4], wsjtMagic)
+	binary.BigEndian.PutUint32(hdr[4:8], 2) // schema 2 — what WSJT-X 2.x speaks
+	binary.BigEndian.PutUint32(hdr[8:12], wsjtMsgLoggedADIF)
+	b.Write(hdr[:])
+	b.Write(buildQString(id))
+	b.Write(buildQString(adif))
+	return b.Bytes()
+}