lightningd: fail fundchannel command when feerate is below feerate_floor

lightningd/opening_control.c

@@ -1,3 +1,4 @@
+#include "bitcoin/feerate.h"
 #include <bitcoin/privkey.h>
 #include <bitcoin/script.h>
 #include <ccan/tal/str/str.h>
@@ -791,6 +792,11 @@ static void json_fund_channel(struct command *cmd,
 		}
 	}
 
+	if (*feerate_per_kw < feerate_floor()) {
+		command_fail(cmd, LIGHTNINGD, "Feerate below feerate floor");
+			return;
+	}
+
 	peer = peer_by_id(cmd->ld, id);
 	if (!peer) {
 		command_fail(cmd, LIGHTNINGD, "Unknown peer");