From f417dfa0e1f20de45421186dd5920c0ba3d2b16b Mon Sep 17 00:00:00 2001
From: Christian Decker <decker.christian@gmail.com>
Date: Sat, 8 Sep 2018 13:37:29 +0200
Subject: [PATCH] chainparams: Always retrieve chainparams by the chain_hash

---
 bitcoin/chainparams.c        | 9 ---------
 bitcoin/chainparams.h        | 8 --------
 lightningd/opening_control.c | 3 ++-
 openingd/opening_wire.csv    | 4 ++--
 openingd/openingd.c          | 6 +++---
 5 files changed, 7 insertions(+), 23 deletions(-)

diff --git a/bitcoin/chainparams.c b/bitcoin/chainparams.c
index cb081718a..33a70340a 100644
--- a/bitcoin/chainparams.c
+++ b/bitcoin/chainparams.c
@@ -82,15 +82,6 @@ const struct chainparams *chainparams_for_network(const char *network_name)
 	return NULL;
 }
 
-const struct chainparams *chainparams_by_index(const int index)
-{
-	if (index >= ARRAY_SIZE(networks) || index < 0) {
-		return NULL;
-	} else {
-		return &networks[index];
-	}
-}
-
 const struct chainparams *chainparams_by_chainhash(const struct bitcoin_blkid *chain_hash)
 {
 	for (size_t i = 0; i < ARRAY_SIZE(networks); i++) {
diff --git a/bitcoin/chainparams.h b/bitcoin/chainparams.h
index 9070a1cd9..2e9071172 100644
--- a/bitcoin/chainparams.h
+++ b/bitcoin/chainparams.h
@@ -28,14 +28,6 @@ struct chainparams {
  */
 const struct chainparams *chainparams_for_network(const char *network_name);
 
-/**
- * chainparams_by_index - Helper to get a network by its numeric index
- *
- * We may not want to pass the network name through to subdaemons, so
- * we allows lookup by index.
- */
-const struct chainparams *chainparams_by_index(const int index);
-
 /**
  * chainparams_by_bip173 - Helper to get a network by its bip173 name
  *
diff --git a/lightningd/opening_control.c b/lightningd/opening_control.c
index 42f0b819a..8d4389084 100644
--- a/lightningd/opening_control.c
+++ b/lightningd/opening_control.c
@@ -730,7 +730,8 @@ void peer_start_openingd(struct peer *peer,
 	 */
 	uc->minimum_depth = peer->ld->config.anchor_confirms;
 
-	msg = towire_opening_init(NULL, get_chainparams(peer->ld)->index,
+	msg = towire_opening_init(NULL,
+				  &get_chainparams(peer->ld)->genesis_blockhash,
 				  &uc->our_config,
 				  max_to_self_delay,
 				  min_effective_htlc_capacity_msat,
diff --git a/openingd/opening_wire.csv b/openingd/opening_wire.csv
index 51ae36777..5a25577c5 100644
--- a/openingd/opening_wire.csv
+++ b/openingd/opening_wire.csv
@@ -3,8 +3,8 @@
 #include <common/derive_basepoints.h>
 
 opening_init,6000
-# Which network are we configured for (as index into the chainparams)?
-opening_init,,network_index,u32
+# Which network are we configured for?
+opening_init,,chain_hash,struct bitcoin_blkid
 # Base configuration we'll offer (channel reserve will vary with amount)
 opening_init,,our_config,struct channel_config
 # Minimum/maximum configuration values we'll accept
diff --git a/openingd/openingd.c b/openingd/openingd.c
index 424f09cc5..b17e0eea3 100644
--- a/openingd/openingd.c
+++ b/openingd/openingd.c
@@ -1095,7 +1095,7 @@ int main(int argc, char *argv[])
 	u8 *msg, *inner;
 	struct pollfd pollfd[3];
 	struct state *state = tal(NULL, struct state);
-	u32 network_index;
+	struct bitcoin_blkid chain_hash;
 	struct secret *none;
 
 	subdaemon_setup(argc, argv);
@@ -1104,7 +1104,7 @@ int main(int argc, char *argv[])
 
 	msg = wire_sync_read(tmpctx, REQ_FD);
 	if (!fromwire_opening_init(tmpctx, msg,
-				   &network_index,
+				   &chain_hash,
 				   &state->localconf,
 				   &state->max_to_self_delay,
 				   &state->min_effective_htlc_capacity_msat,
@@ -1125,7 +1125,7 @@ int main(int argc, char *argv[])
 		fail_if_all_error(inner);
 	}
 
-	state->chainparams = chainparams_by_index(network_index);
+	state->chainparams = chainparams_by_chainhash(&chain_hash);
 	/* Initially we're not associated with a channel, but
 	 * handle_peer_gossip_or_error wants this. */
 	memset(&state->channel_id, 0, sizeof(state->channel_id));