From eb13241672e34b7d982f0644aa9bced34edcf493 Mon Sep 17 00:00:00 2001
From: Kevin Wallace <kevin@pentabarf.net>
Date: Sun, 26 Apr 2026 10:29:08 -0700
Subject: replyTo

---
 ipp/ipp.go | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

(limited to 'ipp/ipp.go')

diff --git a/ipp/ipp.go b/ipp/ipp.go
index c71b590..26eabce 100644
--- a/ipp/ipp.go
+++ b/ipp/ipp.go
@@ -13,6 +13,7 @@ import (
 )
 
 var Trace = flag.Bool("ipp-trace", false, "log IPP protocol traces")
+var Seq = flag.Int("ipp-seq", 0, "IPP sequence counter start value")
 
 var crc8table = [256]byte{
 	0x00, 0x5e, 0xbc, 0xe2, 0x61, 0x3f, 0xdd, 0x83, 0xc2, 0x9c, 0x7e, 0x20, 0xa3, 0xfd, 0x1f, 0x41,
@@ -40,12 +41,12 @@ func crc8(bs ...byte) (x byte) {
 	return
 }
 
-type Handler func(byte, []byte)
+type Handler func(seq, replyTo byte, msgType byte, msgData []byte)
 
 type Session interface {
 	io.Closer
 	io.Writer
-	SendIPP(ippType byte, ippData []byte) error
+	SendIPP(ippType byte, replyTo byte, ippData []byte) error
 }
 
 type session struct {
@@ -81,9 +82,10 @@ func Open(path string, handler Handler) (Session, error) {
 	}
 
 	s := &session{
-		path:    path,
-		fd:      fd,
-		handler: handler,
+		path:       path,
+		fd:         fd,
+		handler:    handler,
+		nextSeqOut: byte(*Seq),
 	}
 	go s.readTask()
 	return s, nil
@@ -128,8 +130,8 @@ func (s *session) handleMsg(bs []byte) (nConsumed int) {
 	if len(bs) < expectedLen {
 		return
 	}
-	_ = bs[1] // seq
-	_ = bs[2] // unknown
+	seq := bs[1] // seq
+	replyTo := bs[2]
 	ippType := bs[3]
 	ippLen := int(bs[4])<<8 + int(bs[5])
 	hdrCRC := bs[6]
@@ -165,7 +167,7 @@ func (s *session) handleMsg(bs []byte) (nConsumed int) {
 		log.Printf("%s < %s%s%s", s.path, hex.EncodeToString(bs[:7]), ellipsis, hex.EncodeToString(bs[7+ippLen:expectedLen]))
 	}
 	if s.handler != nil {
-		s.handler(ippType, ippData)
+		s.handler(seq, replyTo, ippType, ippData)
 	}
 	return
 }
@@ -186,7 +188,7 @@ func (s *session) Write(bs []byte) (int, error) {
 	return unix.Write(s.fd, bs)
 }
 
-func (s *session) SendIPP(ippType byte, ippData []byte) error {
+func (s *session) SendIPP(ippType byte, replyTo byte, ippData []byte) error {
 	s.mu.Lock()
 	s.nextSeqOut++
 	if s.nextSeqOut == 0 {
@@ -195,7 +197,7 @@ func (s *session) SendIPP(ippType byte, ippData []byte) error {
 	seq := s.nextSeqOut
 	s.mu.Unlock()
 	ippLen := len(ippData)
-	ippHdr := []byte{0xbc, seq, 0, ippType, byte(ippLen >> 8), byte(ippLen), 0}
+	ippHdr := []byte{0xbc, seq, replyTo, ippType, byte(ippLen >> 8), byte(ippLen), 0}
 	ippHdr[6] = crc8(ippHdr[:6]...)
 	var msgCRC []byte
 	if ippType&0x80 != 0 {
-- 
cgit v1.2.3