lightningd: use the standard port derivation in connect command

Complete implementation of BOLT1 port derivation proposal lightning/bolts#968

Changelog-Added: rpc: use the standard port derivation in connect command when the port is not specified.

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

bitcoin/chainparams.c

@@ -94,7 +94,7 @@ const struct chainparams networks[] = {
 				      0x2c, 0x42, 0x25, 0xe9, 0x73, 0x98, 0x81,
 				      0x08, 0x00, 0x00, 0x00}}}},
      .rpc_port = 38332,
-     .ln_port = 9735,
+     .ln_port = 39735,
      .cli = "bitcoin-cli",
      .cli_args = "-signet",
      .cli_min_supported_version = 150000,

lightningd/connect_control.c

@@ -1,4 +1,5 @@
 #include "config.h"
+#include <bitcoin/chainparams.h>
 #include <ccan/err/err.h>
 #include <ccan/tal/str/str.h>
 #include <common/configdir.h>
@@ -140,7 +141,7 @@ static struct command_result *json_connect(struct command *cmd,
 		/* Is there a port? */
 		if (!port) {
 			port = tal(cmd, u32);
-			*port = DEFAULT_PORT;
+			*port = chainparams->ln_port;
 		}
 		addr = tal(cmd, struct wireaddr_internal);
 		if (!parse_wireaddr_internal(name, addr, *port, false,

lightningd/lightningd.c

@@ -969,7 +969,7 @@ int main(int argc, char *argv[])
 
 	/*~ Set the default portnum according to the used network
 	 * similarly to what Bitcoin Core does to ports by default. */
-	ld->portnum = DEFAULT_PORT + chainparams->rpc_port - 8332;
+	ld->portnum = chainparams->ln_port;
 
 	/*~ Initialize all the plugins we just registered, so they can
 	 *  do their thing and tell us about themselves (including