Revert dev-uniform padding.

This reverts:

2252bda "connectd: gate uniform message padding behind --dev-uniform-padding"
f844eb0 "lightningd: add dev-uniform-padding flag to lightningd".
b7c05f6 "test: add flag to test_constant_packet_size"

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

connectd/connectd.c

@@ -1695,8 +1695,7 @@ static void connect_init(struct daemon *daemon, const u8 *msg)
 				    &daemon->dev_no_reconnect,
 				    &daemon->dev_fast_reconnect,
 				    &dev_limit_connections_inflight,
-				    &daemon->dev_keep_nagle,
-				    &daemon->dev_uniform_padding)) {
+				    &daemon->dev_keep_nagle)) {
 		/* This is a helper which prints the type expected and the actual
 		 * message, then exits (it should never be called!). */
 		master_badmsg(WIRE_CONNECTD_INIT, msg);
@@ -2532,7 +2531,6 @@ int main(int argc, char *argv[])
 	daemon->dev_exhausted_fds = false;
 	daemon->dev_lightningd_is_slow = false;
 	daemon->dev_keep_nagle = false;
-	daemon->dev_uniform_padding = false;
 	/* We generally allow 1MB per second per peer, except for dev testing */
 	daemon->gossip_stream_limit = 1000000;
 	daemon->incoming_stream_limit = 1000000;

connectd/connectd.h

@@ -320,9 +320,6 @@ struct daemon {
 	/* Allow localhost to be considered "public", only with --developer */
 	bool dev_allow_localhost;
 
-	/* Pad outgoing messages to uniform 1460-byte segments (traffic analysis defence) */
-	bool dev_uniform_padding;
-
 	/* How much to gossip allow a peer every second (bytes) */
 	size_t gossip_stream_limit;
 

connectd/connectd_wire.csv

@@ -29,8 +29,6 @@ msgdata,connectd_init,dev_no_reconnect,bool,
 msgdata,connectd_init,dev_fast_reconnect,bool,
 msgdata,connectd_init,dev_limit_connections_inflight,bool,
 msgdata,connectd_init,dev_keep_nagle,bool,
-# Pad outgoing messages to uniform 1460-byte segments (traffic analysis defence)
-msgdata,connectd_init,dev_uniform_padding,bool,
 
 # Connectd->master, here are the addresses I bound, can announce.
 msgtype,connectd_init_reply,2100

lightningd/connect_control.c

@@ -727,8 +727,7 @@ int connectd_init(struct lightningd *ld)
 				   !ld->reconnect,
 				   ld->dev_fast_reconnect,
 				   ld->dev_limit_connections_inflight,
-				   ld->dev_keep_nagle,
-				   ld->dev_uniform_padding);
+				   ld->dev_keep_nagle);
 
 	subd_req(ld->connectd, ld->connectd, take(msg), -1, 0,
 		 connect_init_done, NULL);

lightningd/lightningd.c

@@ -150,7 +150,6 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->dev_strict_forwarding = false;
 	ld->dev_limit_connections_inflight = false;
 	ld->dev_keep_nagle = false;
-	ld->dev_uniform_padding = false;
 
 	/*~ We try to ensure enough fds for twice the number of channels
 	 * we start with.  We have a developer option to change that factor

lightningd/lightningd.h

@@ -369,9 +369,6 @@ struct lightningd {
 	/* Tell connectd we don't want TCP_NODELAY */
 	bool dev_keep_nagle;
 
-	/* Pad outgoing messages to uniform 1460-byte segments (traffic analysis defence) */
-	bool dev_uniform_padding;
-
 	/* tor support */
 	struct wireaddr *proxyaddr;
 	bool always_use_proxy;

lightningd/options.c

@@ -952,10 +952,6 @@ static void dev_register_opts(struct lightningd *ld)
 		       opt_set_bool,
 		       &ld->dev_keep_nagle,
 		       "Tell connectd not to set TCP_NODELAY.");
-	clnopt_noarg("--dev-uniform-padding", OPT_DEV,
-		       opt_set_bool,
-		       &ld->dev_uniform_padding,
-		       "Pad all outgoing peer messages to uniform 1460-byte segments");
 	/* This is handled directly in daemon_developer_mode(), so we ignore it here */
 	clnopt_noarg("--dev-debug-self", OPT_DEV,
 		     opt_ignore,

tests/test_connection.py

@@ -4823,7 +4823,7 @@ def test_constant_packet_size(node_factory, tcp_capture):
     Test that TCP packets between nodes are constant size.  This will be skipped unless
     you can run `dumpcap` (usually means you have to be in the `wireshark` group).
     """
-    l1, l2, l3, l4 = node_factory.get_nodes(4, opts={'dev-uniform-padding': None})
+    l1, l2, l3, l4 = node_factory.get_nodes(4)
 
     # Encrypted setup BOLT 8 has some short packets.
     l1.connect(l2)