From 112012bf5b8e0bd931c7bcdb60f8f1254e691461 Mon Sep 17 00:00:00 2001
From: Josh Deprez <josh.deprez@gmail.com>
Date: Sun, 7 Apr 2024 15:14:54 +1000
Subject: [PATCH] WIP RTMP machine

---
 main.go | 14 +++++++--
 rtmp.go | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+), 2 deletions(-)
 create mode 100644 rtmp.go

diff --git a/main.go b/main.go
index 84fdeb4..e96f5e6 100644
--- a/main.go
+++ b/main.go
@@ -125,6 +125,7 @@ func main() {
 		}()
 	}
 
+	// --------------- Configured peer setup ---------------
 	for _, peerStr := range cfg.Peers {
 		if !hasPortRE.MatchString(peerStr) {
 			peerStr += ":387"
@@ -152,11 +153,20 @@ func main() {
 		goPeerHandler(peer)
 	}
 
-	// AppleTalk packet loops
+	// -------------------- AARP --------------------
 	aarpMachine := NewAARPMachine(cfg, pcapHandle, myHWAddr)
 	aarpCh := make(chan *ethertalk.Packet, 1024)
 	go aarpMachine.Run(ctx, aarpCh)
 
+	// -------------------- RTMP --------------------
+	rtmpMachine := &RTMPMachine{
+		aarp:       aarpMachine,
+		cfg:        cfg,
+		pcapHandle: pcapHandle,
+	}
+	go rtmpMachine.Run(ctx)
+
+	// ---------- Raw AppleTalk/AARP inbound ----------
 	go func() {
 		for {
 			if ctx.Err() != nil {
@@ -212,7 +222,7 @@ func main() {
 		}
 	}()
 
-	// AURP packet loop
+	// ---------- AURP inbound ----------
 	for {
 		if ctx.Err() != nil {
 			return
diff --git a/rtmp.go b/rtmp.go
new file mode 100644
index 0000000..bfaf1dd
--- /dev/null
+++ b/rtmp.go
@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"gitea.drjosh.dev/josh/jrouter/atalk/rtmp"
+	"github.com/google/gopacket/pcap"
+	"github.com/sfiera/multitalk/pkg/ddp"
+	"github.com/sfiera/multitalk/pkg/ethertalk"
+)
+
+// RTMPMachine implements RTMP on an AppleTalk network attached to the router.
+type RTMPMachine struct {
+	aarp       *AARPMachine
+	cfg        *config
+	pcapHandle *pcap.Handle
+}
+
+func (m *RTMPMachine) Run(ctx context.Context) error {
+	bcastTicker := time.NewTicker(10 * time.Second)
+	defer bcastTicker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+
+		case <-bcastTicker.C:
+			// Broadcast an RTMP Data
+			myAddr, ok := m.aarp.Address()
+			if !ok {
+				continue
+			}
+
+			dataPkt := &rtmp.DataPacket{
+				RouterAddr: myAddr.Proto,
+				Extended:   true,
+				NetworkTuples: []rtmp.NetworkTuple{
+					// "The first tuple in RTMP Data packets sent on extended
+					// networks ... indicates the network number range assigned
+					// to that network."
+					{
+						Extended:   true,
+						RangeStart: m.cfg.EtherTalk.NetStart,
+						RangeEnd:   m.cfg.EtherTalk.NetEnd,
+						Distance:   0,
+					},
+				},
+			}
+			// TODO: append more networks!
+
+			dataPktRaw, err := dataPkt.Marshal()
+			if err != nil {
+				log.Printf("RTMP: Couldn't marshal Data packet: %v", err)
+				continue
+			}
+
+			ddpPkt := ddp.ExtPacket{
+				ExtHeader: ddp.ExtHeader{
+					Size:      uint16(len(dataPktRaw)),
+					DstNet:    0,
+					DstNode:   0xff, // broadcast packet
+					DstSocket: 1,    // the special RTMP socket
+					SrcNet:    myAddr.Proto.Network,
+					SrcNode:   myAddr.Proto.Node,
+					SrcSocket: 1, // the special RTMP socket
+					Proto:     ddp.ProtoRTMPResp,
+				},
+				Data: dataPktRaw,
+			}
+
+			ethFrame, err := ethertalk.AppleTalk(ethertalk.AppleTalkBroadcast, ddpPkt)
+			if err != nil {
+				log.Printf("RTMP: Couldn't create EtherTalk frame: %v", err)
+			}
+
+			ethFrameRaw, err := ethertalk.Marshal(*ethFrame)
+			if err != nil {
+				log.Printf("RTMP: Couldn't marshal EtherTalk frame: %v", err)
+			}
+
+			if err := m.pcapHandle.WritePacketData(ethFrameRaw); err != nil {
+				log.Printf("RTMP: Couldn't write frame: %v", err)
+			}
+		}
+	}
+}