From e2ebbfcfedb79e777cb5499abab0a3ec5e18f732 Mon Sep 17 00:00:00 2001
From: Jesse de Wit <witdejesse@hotmail.com>
Date: Fri, 11 Aug 2023 11:47:06 +0200
Subject: [PATCH] lsps0: implement cln custommsg client

---
 cln/custom_msg_client.go | 166 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 cln/custom_msg_client.go

diff --git a/cln/custom_msg_client.go b/cln/custom_msg_client.go
new file mode 100644
index 00000000..9b031443
--- /dev/null
+++ b/cln/custom_msg_client.go
@@ -0,0 +1,166 @@
+package cln
+
+import (
+	"context"
+	"encoding/binary"
+	"encoding/hex"
+	"log"
+	"sync"
+	"time"
+
+	"github.com/breez/lspd/cln_plugin/proto"
+	"github.com/breez/lspd/config"
+	"github.com/breez/lspd/lightning"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/keepalive"
+	"google.golang.org/grpc/status"
+)
+
+type CustomMsgClient struct {
+	lightning.CustomMsgClient
+	pluginAddress string
+	client        *ClnClient
+	pluginClient  proto.ClnPluginClient
+	initWg        sync.WaitGroup
+	stopRequested bool
+	ctx           context.Context
+	cancel        context.CancelFunc
+	recvQueue     chan *lightning.CustomMessage
+}
+
+func NewCustomMsgClient(conf *config.ClnConfig, client *ClnClient) *CustomMsgClient {
+	c := &CustomMsgClient{
+		pluginAddress: conf.PluginAddress,
+		client:        client,
+		recvQueue:     make(chan *lightning.CustomMessage, 10000),
+	}
+
+	c.initWg.Add(1)
+	return c
+}
+
+func (c *CustomMsgClient) Start() error {
+	ctx, cancel := context.WithCancel(context.Background())
+	log.Printf("Dialing cln plugin on '%s'", c.pluginAddress)
+	conn, err := grpc.DialContext(
+		ctx,
+		c.pluginAddress,
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithKeepaliveParams(keepalive.ClientParameters{
+			Time:    time.Duration(10) * time.Second,
+			Timeout: time.Duration(10) * time.Second,
+		}),
+	)
+	if err != nil {
+		log.Printf("grpc.Dial error: %v", err)
+		cancel()
+		return err
+	}
+
+	c.pluginClient = proto.NewClnPluginClient(conn)
+	c.ctx = ctx
+	c.cancel = cancel
+	c.stopRequested = false
+	return c.listen()
+}
+
+func (i *CustomMsgClient) WaitStarted() {
+	i.initWg.Wait()
+}
+
+func (i *CustomMsgClient) listen() error {
+	inited := false
+
+	defer func() {
+		if !inited {
+			i.initWg.Done()
+		}
+		log.Printf("CLN custom msg listen(): stopping.")
+	}()
+
+	for {
+		if i.ctx.Err() != nil {
+			return i.ctx.Err()
+		}
+
+		log.Printf("Connecting CLN msg stream.")
+		msgClient, err := i.pluginClient.CustomMsgStream(i.ctx, &proto.CustomMessageRequest{})
+		if err != nil {
+			log.Printf("pluginClient.CustomMsgStream(): %v", err)
+			<-time.After(time.Second)
+			continue
+		}
+
+		for {
+			if i.ctx.Err() != nil {
+				return i.ctx.Err()
+			}
+
+			if !inited {
+				inited = true
+				i.initWg.Done()
+			}
+
+			// Stop receiving if stop if requested.
+			if i.stopRequested {
+				return nil
+			}
+
+			request, err := msgClient.Recv()
+			if err != nil {
+				// If it is just the error result of the context cancellation
+				// the we exit silently.
+				status, ok := status.FromError(err)
+				if ok && status.Code() == codes.Canceled {
+					log.Printf("Got code canceled. Break.")
+					break
+				}
+
+				// Otherwise it an unexpected error, we log.
+				log.Printf("unexpected error in interceptor.Recv() %v", err)
+				break
+			}
+
+			payload, err := hex.DecodeString(request.Payload)
+			if err != nil {
+				log.Printf("Error hex decoding cln custom msg payload from peer '%s': %v", request.PeerId, err)
+				continue
+			}
+
+			if len(payload) < 3 {
+				log.Printf("UNUSUAL: Custom msg payload from peer '%s' is too small", request.PeerId)
+				continue
+			}
+
+			t := binary.BigEndian.Uint16(payload)
+			payload = payload[2:]
+			i.recvQueue <- &lightning.CustomMessage{
+				PeerId: request.PeerId,
+				Type:   uint32(t),
+				Data:   payload,
+			}
+		}
+
+		<-time.After(time.Second)
+	}
+}
+
+func (c *CustomMsgClient) Recv() (*lightning.CustomMessage, error) {
+	select {
+	case msg := <-c.recvQueue:
+		return msg, nil
+	case <-c.ctx.Done():
+		return nil, c.ctx.Err()
+	}
+}
+
+func (c *CustomMsgClient) Send(msg *lightning.CustomMessage) error {
+	var t [2]byte
+	binary.BigEndian.PutUint16(t[:], uint16(msg.Type))
+
+	m := hex.EncodeToString(t[:]) + hex.EncodeToString(msg.Data)
+	_, err := c.client.client.SendCustomMessage(msg.PeerId, m)
+	return err
+}