fix: restore global fee settings

channeld/channel_wire.csv

@@ -23,6 +23,8 @@ channel_init,,old_remote_per_commit,struct pubkey
 channel_init,,funder,enum side
 channel_init,,fee_base,u32
 channel_init,,fee_proportional,u32
+channel_init,,fee_base_global,u32
+channel_init,,fee_proportional_global,u32
 channel_init,,local_msatoshi,u64
 channel_init,,our_basepoints,struct basepoints
 channel_init,,our_funding_pubkey,struct pubkey

channeld/channeld.c

@@ -131,6 +131,10 @@ struct peer {
 	u32 fee_base;
 	u32 fee_per_satoshi;
 
+	/* fee rates used for restoring global settings */
+	u32 fee_base_global;
+	u32 fee_per_satoshi_global;
+
 	/* The scriptpubkey to use for shutting down. */
 	u8 *final_scriptpubkey;
 
@@ -2494,6 +2498,12 @@ static void handle_json_feerates(struct peer *peer, const u8 *inmsg)
 				       &peer->fee_per_satoshi))
 		master_badmsg(WIRE_CHANNEL_JSON_FEERATES, inmsg);
 
+	// setting values to 0 means restore global values
+	if (peer->fee_base == 0)
+		peer->fee_base = peer->fee_base_global;
+	if (peer->fee_per_satoshi == 0)
+		peer->fee_per_satoshi = peer->fee_per_satoshi_global;
+
 	send_channel_update(peer, 0);
 }
 
@@ -2716,6 +2726,8 @@ static void init_channel(struct peer *peer)
 				   &funder,
 				   &peer->fee_base,
 				   &peer->fee_per_satoshi,
+				   &peer->fee_base_global,
+				   &peer->fee_per_satoshi_global,
 				   &local_msatoshi,
 				   &points[LOCAL],
 				   &funding_pubkey[LOCAL],

lightningd/channel_control.c

@@ -363,6 +363,8 @@ void peer_start_channeld(struct channel *channel,
 				      channel->funder,
 				      fee_base,
 				      fee_per_satoshi,
+				      cfg->fee_base,
+				      cfg->fee_per_satoshi,
 				      channel->our_msatoshi,
 				      &channel->local_basepoints,
 				      &channel->local_funding_pubkey,