From 8afc75f1fc0750d81dfe25f3835cbaab702fd0b5 Mon Sep 17 00:00:00 2001
From: Zack Scholl <zack.scholl@gmail.com>
Date: Sun, 23 Sep 2018 05:39:23 -0700
Subject: [PATCH] listen for interrupt in websockets

---
 src/croc/sending.go        | 4 ++++
 src/recipient/recipient.go | 3 +++
 src/sender/sender.go       | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/src/croc/sending.go b/src/croc/sending.go
index c6f8ec2..192a36d 100644
--- a/src/croc/sending.go
+++ b/src/croc/sending.go
@@ -152,6 +152,10 @@ func (c *Croc) sendReceive(websocketAddress, fname, codephrase string, isSender
 			return nil
 		case <-interrupt:
 			log.Debug("interrupt")
+			err = sock.WriteMessage(websocket.TextMessage, []byte("interrupt"))
+			if err != nil {
+				return err
+			}
 
 			// Cleanly close the connection by sending a close message and then
 			// waiting (with timeout) for the server to close the connection.
diff --git a/src/recipient/recipient.go b/src/recipient/recipient.go
index 9fb70c2..3ebd093 100644
--- a/src/recipient/recipient.go
+++ b/src/recipient/recipient.go
@@ -73,6 +73,9 @@ func receive(isLocal bool, c *websocket.Conn, codephrase string, noPrompt bool,
 		if messageType == websocket.PongMessage || messageType == websocket.PingMessage {
 			continue
 		}
+		if messageType == websocket.TextMessage && bytes.Equal(messsage, "interrupt") {
+			return errors.New("interrupted by other party")
+		}
 
 		log.Debugf("got %d: %s", messageType, message)
 		switch step {
diff --git a/src/sender/sender.go b/src/sender/sender.go
index 3686605..0929256 100644
--- a/src/sender/sender.go
+++ b/src/sender/sender.go
@@ -78,6 +78,9 @@ func send(isLocal bool, c *websocket.Conn, fname string, codephrase string, useC
 		if messageType == websocket.PongMessage || messageType == websocket.PingMessage {
 			continue
 		}
+		if messageType == websocket.TextMessage && bytes.Equal(messsage, "interrupt") {
+			return errors.New("interrupted by other party")
+		}
 		log.Debugf("got %d: %s", messageType, message)
 		switch step {
 		case 0: