experimental-websocket-port: option to create a WebSocket port.

Signed-off-by: Rusty Russell <[email protected]>

doc/lightning-listconfigs.7.md

@@ -56,6 +56,7 @@ On success, an object is returned, containing:
 - **experimental-onion-messages** (boolean, optional): `experimental-onion-messages` field from config or cmdline, or default
 - **experimental-offers** (boolean, optional): `experimental-offers` field from config or cmdline, or default
 - **experimental-shutdown-wrong-funding** (boolean, optional): `experimental-shutdown-wrong-funding` field from config or cmdline, or default
+- **experimental-websocket-port** (u16, optional): `experimental-websocket-port` field from config or cmdline, or default
 - **rgb** (hex, optional): `rgb` field from config or cmdline, or default (always 6 characters)
 - **alias** (string, optional): `alias` field from config or cmdline, or default
 - **pid-file** (string, optional): `pid-file` field from config or cmdline, or default
@@ -205,4 +206,4 @@ RESOURCES
 ---------
 
 Main web site: <https://github.com/ElementsProject/lightning>
-[comment]: # ( SHA256STAMP:7bb40fc8fac201b32d9701b02596d0fa59eb14a3baf606439cbf96dc11548ed4)
+[comment]: # ( SHA256STAMP:47c067588120e0f9a71206313685cebb2a8c515e9b04b688b202d2772c8f8146)

doc/lightningd-config.5.md

@@ -517,6 +517,13 @@ about whether to add funds or not to a proposed channel is handled
 automatically by a plugin that implements the appropriate logic for
 your needs. The default behavior is to not contribute funds.
 
+ **experimental-websocket-port**
+
+Specifying this enables support for accepting incoming WebSocket
+connections on that port, on any IPv4 and IPv6 addresses you listen
+to.  The normal protocol is expected to be sent over WebSocket binary
+frames once the connection is upgraded.
+
 BUGS
 ----
 

doc/schemas/listconfigs.schema.json

@@ -121,6 +121,10 @@
 	    "type": "boolean",
 	    "description": "`experimental-shutdown-wrong-funding` field from config or cmdline, or default"
 	},
+	"experimental-websocket-port": {
+	    "type": "u16",
+	    "description": "`experimental-websocket-port` field from config or cmdline, or default"
+	},
 	"rgb": {
 	    "type": "hex",
 	    "description": "`rgb` field from config or cmdline, or default",

lightningd/connect_control.c

@@ -350,7 +350,10 @@ int connectd_init(struct lightningd *ld)
 	int hsmfd;
 	struct wireaddr_internal *wireaddrs = ld->proposed_wireaddr;
 	enum addr_listen_announce *listen_announce = ld->proposed_listen_announce;
-	const char *websocket_helper_path = "";
+	const char *websocket_helper_path;
+
+	websocket_helper_path = subdaemon_path(tmpctx, ld,
+					       "lightning_websocketd");
 
 	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, fds) != 0)
 		fatal("Could not socketpair for connectd<->gossipd");
@@ -384,7 +387,7 @@ int connectd_init(struct lightningd *ld)
 	    ld->config.use_v3_autotor,
 	    ld->config.connection_timeout_secs,
 	    websocket_helper_path,
-	    0);
+	    ld->websocket_port);
 
 	subd_req(ld->connectd, ld->connectd, take(msg), -1, 0,
 		 connect_init_done, NULL);

lightningd/lightningd.c

@@ -216,6 +216,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->always_use_proxy = false;
 	ld->pure_tor_setup = false;
 	ld->tor_service_password = NULL;
+	ld->websocket_port = 0;
 
 	/*~ This is initialized later, but the plugin loop examines this,
 	 * so set it to NULL explicitly now. */

lightningd/lightningd.h

@@ -284,6 +284,9 @@ struct lightningd {
 	/* Array of (even) TLV types that we should allow. This is required
 	 * since we otherwise would outright reject them. */
 	u64 *accept_extra_tlv_types;
+
+	/* EXPERIMENTAL: websocket port if non-zero */
+	u16 websocket_port;
 };
 
 /* Turning this on allows a tal allocation to return NULL, rather than aborting.

lightningd/options.c

@@ -850,6 +850,21 @@ static char *opt_set_wumbo(struct lightningd *ld)
 	return NULL;
 }
 
+static char *opt_set_websocket_port(const char *arg, struct lightningd *ld)
+{
+	u32 port;
+	char *err;
+
+	err = opt_set_u32(arg, &port);
+	if (err)
+		return err;
+
+	ld->websocket_port = port;
+	if (ld->websocket_port != port)
+		return tal_fmt(NULL, "'%s' is out of range", arg);
+	return NULL;
+}
+
 static char *opt_set_dual_fund(struct lightningd *ld)
 {
 	/* Dual funding implies anchor outputs */
@@ -1051,6 +1066,11 @@ static void register_opts(struct lightningd *ld)
 			 "--subdaemon=hsmd:remote_signer "
 			 "would use a hypothetical remote signing subdaemon.");
 
+	opt_register_arg("--experimental-websocket-port",
+			 opt_set_websocket_port, NULL,
+			 ld,
+			 "experimental: alternate port for peers to connect"
+			 " using WebSockets (RFC6455)");
 	opt_register_logging(ld);
 	opt_register_version();
 
@@ -1463,6 +1483,11 @@ static void add_config(struct lightningd *ld,
 			json_add_opt_disable_plugins(response, ld->plugins);
 		} else if (opt->cb_arg == (void *)opt_force_feerates) {
 			answer = fmt_force_feerates(name0, ld->force_feerates);
+		} else if (opt->cb_arg == (void *)opt_set_websocket_port) {
+			if (ld->websocket_port)
+				json_add_u32(response, name0,
+					     ld->websocket_port);
+			return;
 		} else if (opt->cb_arg == (void *)opt_important_plugin) {
 			/* Do nothing, this is already handled by
 			 * opt_add_plugin.  */

requirements.txt

@@ -2,6 +2,7 @@
 mrkd ~= 0.1.6
 Mako ~= 1.1.3
 flake8 ~= 3.7.8
+websocket-client
 
 ./contrib/pyln-client
 ./contrib/pyln-proto

tests/test_connection.py

@@ -2,7 +2,9 @@
 from fixtures import *  # noqa: F401,F403
 from fixtures import TEST_NETWORK
 from flaky import flaky  # noqa: F401
+from ephemeral_port_reserve import reserve  # type: ignore
 from pyln.client import RpcError, Millisatoshi
+import pyln.proto.wire as wire
 from utils import (
     only_one, wait_for, sync_blockheight, TIMEOUT,
     expected_peer_features, expected_node_features,
@@ -20,6 +22,7 @@
 import shutil
 import time
 import unittest
+import websocket
 
 
 def test_connect(node_factory):
@@ -3740,6 +3743,58 @@ def test_old_feerate(node_factory):
     l1.pay(l2, 1000)
 
 
+def test_websocket(node_factory):
+    ws_port = reserve()
+    l1 = node_factory.get_node(options={'experimental-websocket-port': ws_port, 'log-level': 'io'})
+    assert l1.rpc.listconfigs()['experimental-websocket-port'] == ws_port
+
+    # Adapter to turn websocket into a stream "connection"
+    class BinWebSocket(object):
+        def __init__(self, hostname, port):
+            self.ws = websocket.WebSocket()
+            self.ws.connect("ws://" + hostname + ":" + str(port))
+            self.recvbuf = bytes()
+
+        def send(self, data):
+            self.ws.send(data, websocket.ABNF.OPCODE_BINARY)
+
+        def recv(self, maxlen):
+            while len(self.recvbuf) < maxlen:
+                self.recvbuf += self.ws.recv()
+
+            ret = self.recvbuf[:maxlen]
+            self.recvbuf = self.recvbuf[maxlen:]
+            return ret
+
+    ws = BinWebSocket('localhost', ws_port)
+    lconn = wire.LightningConnection(ws,
+                                     wire.PublicKey(bytes.fromhex(l1.info['id'])),
+                                     wire.PrivateKey(bytes([1] * 32)),
+                                     is_initiator=True)
+
+    l1.daemon.wait_for_log('Websocket connection in from')
+
+    # Perform handshake.
+    lconn.shake()
+
+    # Expect to receive init msg.
+    msg = lconn.read_message()
+    assert int.from_bytes(msg[0:2], 'big') == 16
+
+    # Echo same message back.
+    lconn.send_message(msg)
+
+    # Now try sending a ping, ask for 50 bytes
+    msg = bytes((0, 18, 0, 50, 0, 0))
+    lconn.send_message(msg)
+
+    # Could actually reply with some gossip msg!
+    while True:
+        msg = lconn.read_message()
+        if int.from_bytes(msg[0:2], 'big') == 19:
+            break
+
+
 @pytest.mark.developer("dev-disconnect required")
 def test_ping_timeout(node_factory):
     # Disconnects after this, but doesn't know it.