lightningd: `--message-padding` to allow users to disable padding altogether.

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 438771a2..38bc39ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ This release is named by @Chand-ra.
 ### Added
 
  - Protocol: we now pad all peer messages to make them the same length (excluding LND < v21 and current Eclair). ([#8893], [#9022])
+ - Config: `message-padding` option can be set to `false` to disable it for all peers. ([#9068])
  - JSON-RPC: `bkpr-report` allows flexible summaries of bookkeeper income. ([#8937])
  - Config: `bkpr-currency` option to record conversion rate at each bookkeeper event. ([#8937])
  - JSON-RPC: `currencyconvert` and `currencyrate` via the new plugin `cln-currencyrate` ([#8842], [#8937])
@@ -137,6 +138,7 @@ Note: You should always set `allow-deprecated-apis=false` to test for changes.
 [#9022]: https://github.com/ElementsProject/lightning/pull/9022
 [#9046]: https://github.com/ElementsProject/lightning/pull/9046
 [#9047]: https://github.com/ElementsProject/lightning/pull/9047
+[#9068]: https://github.com/ElementsProject/lightning/pull/9068
 [v26.04rc3]: https://github.com/ElementsProject/lightning/releases/tag/v26.04rc3
 
 
diff --git a/connectd/connectd.c b/connectd/connectd.c
index 343a59ec..54ac0891 100644
--- a/connectd/connectd.c
+++ b/connectd/connectd.c
@@ -1687,6 +1687,7 @@ static void connect_init(struct daemon *daemon, const u8 *msg)
 				    &tor_password,
 				    &daemon->timeout_secs,
 				    &daemon->websocket_helper,
+				    &daemon->message_padding,
 				    &daemon->dev_fast_gossip,
 				    &dev_disconnect,
 				    &daemon->dev_no_ping_timer,
diff --git a/connectd/connectd.h b/connectd/connectd.h
index d3885c17..11665cc2 100644
--- a/connectd/connectd.h
+++ b/connectd/connectd.h
@@ -367,6 +367,9 @@ struct daemon {
 	 * (--dev-limit-connectsion-inflight sets this to 1 for testing). */
 	size_t max_connect_in_flight;
 
+	/* Add padding to messages (if peer seems ok) */
+	bool message_padding;
+
 	/* Hack to speed up gossip timer */
 	bool dev_fast_gossip;
 	/* Hack to avoid ping timeouts */
diff --git a/connectd/connectd_wire.csv b/connectd/connectd_wire.csv
index d5f6aee3..c1361a59 100644
--- a/connectd/connectd_wire.csv
+++ b/connectd/connectd_wire.csv
@@ -18,6 +18,7 @@ msgdata,connectd_init,use_dns,bool,
 msgdata,connectd_init,tor_password,wirestring,
 msgdata,connectd_init,timeout_secs,u32,
 msgdata,connectd_init,websocket_helper,wirestring,
+msgdata,connectd_init,message_padding,bool,
 msgdata,connectd_init,dev_fast_gossip,bool,
 # If this is set, then fd 5 is dev_disconnect_fd.
 msgdata,connectd_init,dev_disconnect,bool,
diff --git a/connectd/multiplex.c b/connectd/multiplex.c
index 7dbacec1..46e3aeb0 100644
--- a/connectd/multiplex.c
+++ b/connectd/multiplex.c
@@ -491,9 +491,13 @@ static bool have_empty_encrypted_queue(const struct peer *peer)
  * "Phoenix-specific custom splices implementation" which Tbast
  * indicates is being phased out.  So if they offer that, don't send
  * such pings. */
+
+/* Oh, and then there was a node running LND master.  And those running
+ * LND with LNDK: so we added global disable. */
 static bool use_uniform_writes(const struct peer *peer)
 {
-	return feature_offered(peer->their_features, OPT_ONION_MESSAGES)
+	return peer->daemon->message_padding
+		&& feature_offered(peer->their_features, OPT_ONION_MESSAGES)
 		&& !feature_offered(peer->their_features, 154);
 }
 
diff --git a/doc/lightningd-config.5.md b/doc/lightningd-config.5.md
index 6df1d0f8..e85a1a19 100644
--- a/doc/lightningd-config.5.md
+++ b/doc/lightningd-config.5.md
@@ -707,6 +707,12 @@ all DNS lookups, to avoid leaking information.
 
   Disable the DNS bootstrapping mechanism to find a node by its node ID.
 
+* **message-padding**=*BOOL*
+
+  Normally `connectd` will send extra bytes to peers to make messages
+uniform length.  Some implementations don't accept these extra bytes:
+if we can't detect them, this option sets to `false` will disable it.
+
 * **tor-service-password**=*PASSWORD*
 
   Set a Tor control password, which may be needed for *autotor:* to
diff --git a/lightningd/connect_control.c b/lightningd/connect_control.c
index e95a04db..9c8afa96 100644
--- a/lightningd/connect_control.c
+++ b/lightningd/connect_control.c
@@ -719,6 +719,7 @@ int connectd_init(struct lightningd *ld)
 				   ld->tor_service_password ? ld->tor_service_password : "",
 				   ld->config.connection_timeout_secs,
 				   websocket_helper_path,
+				   ld->message_padding,
 				   ld->dev_fast_gossip,
 				   ld->dev_disconnect_fd >= 0,
 				   ld->dev_no_ping_timer,
diff --git a/lightningd/lightningd.c b/lightningd/lightningd.c
index b0b2030a..8847e663 100644
--- a/lightningd/lightningd.c
+++ b/lightningd/lightningd.c
@@ -372,6 +372,12 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->autoconnect_seeker_peers = 10;
 
 	ld->fronting_nodes = tal_arr(ld, struct node_id, 0);
+
+	/*~ connectd usually uses "no-reply" pings to fill out messages
+	 * where needed to make them uniform length.  Some implementations
+	 * don't like it, so it can be disabled. */
+	ld->message_padding = true;
+
 	return ld;
 }
 
diff --git a/lightningd/lightningd.h b/lightningd/lightningd.h
index 9edba38d..3b4e0e84 100644
--- a/lightningd/lightningd.h
+++ b/lightningd/lightningd.h
@@ -434,6 +434,9 @@ struct lightningd {
 
 	/* Nodes to use for invoices / offers */
 	struct node_id *fronting_nodes;
+
+	/* Whether connectd should pad messages to make them equal length */
+	bool message_padding;
 };
 
 /* Turning this on allows a tal allocation to return NULL, rather than aborting.
diff --git a/lightningd/options.c b/lightningd/options.c
index b185d7ea..b724b200 100644
--- a/lightningd/options.c
+++ b/lightningd/options.c
@@ -1668,6 +1668,10 @@ static void register_opts(struct lightningd *ld)
 			       opt_set_talstr, NULL,
 			       &ld->old_bookkeeper_db,
 			       opt_hidden);
+	clnopt_witharg("--message-padding", OPT_SHOWBOOL,
+		       opt_set_bool_arg, opt_show_bool,
+		       &ld->message_padding,
+		       "If true (the default), pad all messages to peers to make them equal length");
 
 	dev_register_opts(ld);
 }