lightningd: put min/max feerates into db, struct channel.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/channel.c

@@ -151,7 +151,9 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    bool last_was_revoke,
 			    /* NULL or stolen */
 			    struct changed_htlc *last_sent_commit,
-			    u32 first_blocknum)
+			    u32 first_blocknum,
+			    u32 min_possible_feerate,
+			    u32 max_possible_feerate)
 {
 	struct channel *channel = tal(peer->ld, struct channel);
 
@@ -204,6 +206,8 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 	channel->last_was_revoke = last_was_revoke;
 	channel->last_sent_commit = tal_steal(channel, last_sent_commit);
 	channel->first_blocknum = first_blocknum;
+	channel->min_possible_feerate = min_possible_feerate;
+	channel->max_possible_feerate = max_possible_feerate;
 	derive_channel_seed(peer->ld, &channel->seed, &peer->id, channel->dbid);
 
 	list_add_tail(&peer->channels, &channel->list);

lightningd/channel.h

@@ -90,6 +90,9 @@ struct channel {
 	/* Blockheight at creation, scans for funding confirmations
 	 * will start here */
 	u64 first_blocknum;
+
+	/* Feerate range */
+	u32 min_possible_feerate, max_possible_feerate;
 };
 
 struct channel *new_channel(struct peer *peer, u64 dbid,
@@ -126,7 +129,9 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    bool last_was_revoke,
 			    /* NULL or stolen */
 			    struct changed_htlc *last_sent_commit,
-			    u32 first_blocknum);
+			    u32 first_blocknum,
+			    u32 min_possible_feerate,
+			    u32 max_possible_feerate);
 
 void delete_channel(struct channel *channel);
 

lightningd/onchain_control.c

@@ -418,7 +418,8 @@ enum watch_result funding_spent(struct channel *channel,
 				  3,
 				  channel->last_htlc_sigs,
 				  tal_count(stubs),
-				  0, 250000);
+				  channel->min_possible_feerate,
+				  channel->max_possible_feerate);
 	subd_send_msg(channel->owner, take(msg));
 
 	/* FIXME: Don't queue all at once, use an empty cb... */

lightningd/opening_control.c

@@ -211,7 +211,8 @@ wallet_commit_channel(struct lightningd *ld,
 			      NULL, /* No remote_shutdown_scriptpubkey yet */
 			      final_key_idx, false,
 			      NULL, /* No commit sent yet */
-			      uc->first_blocknum);
+			      uc->first_blocknum,
+			      feerate, feerate);
 
 	/* Now we finally put it in the database. */
 	wallet_channel_insert(ld->wallet, channel);

lightningd/peer_htlcs.c

@@ -1022,6 +1022,10 @@ void peer_sending_commitsig(struct channel *channel, const u8 *msg)
 
 	/* Update their feerate. */
 	channel->channel_info.feerate_per_kw[REMOTE] = feerate;
+	if (feerate > channel->max_possible_feerate)
+		channel->max_possible_feerate = feerate;
+	if (feerate < channel->min_possible_feerate)
+		channel->min_possible_feerate = feerate;
 
 	if (!peer_save_commitsig_sent(channel, commitnum))
 		return;
@@ -1185,6 +1189,11 @@ void peer_got_commitsig(struct channel *channel, const u8 *msg)
 		= channel->channel_info.feerate_per_kw[REMOTE]
 		= feerate;
 
+	if (feerate > channel->max_possible_feerate)
+		channel->max_possible_feerate = feerate;
+	if (feerate < channel->min_possible_feerate)
+		channel->min_possible_feerate = feerate;
+
 	/* Since we're about to send revoke, bump state again. */
 	if (!peer_sending_revocation(channel, added, fulfilled, failed, changed))
 		return;

wallet/db.c

@@ -276,6 +276,12 @@ char *dbmigrations[] = {
     "  FROM utxoset LEFT OUTER JOIN blocks on (blockheight == blocks.height) "
     "  WHERE blocks.hash IS NULL"
     ");",
+    /* Record feerate range, to optimize onchaind grinding actual fees. */
+    "ALTER TABLE channels ADD min_possible_feerate INTEGER;",
+    "ALTER TABLE channels ADD max_possible_feerate INTEGER;",
+    /* https://bitcoinfees.github.io/#1d says Dec 17 peak was ~1M sat/kb
+     * which is 250,000 sat/Sipa */
+    "UPDATE channels SET min_possible_feerate=0, max_possible_feerate=250000;",
     NULL,
 };
 

wallet/wallet.c

@@ -645,7 +645,9 @@ static struct channel *wallet_stmt2channel(const tal_t *ctx, struct wallet *w, s
 			   final_key_idx,
 			   sqlite3_column_int(stmt, 34) != 0,
 			   last_sent_commit,
-			   sqlite3_column_int64(stmt, 35));
+			   sqlite3_column_int64(stmt, 35),
+			   sqlite3_column_int(stmt, 36),
+			   sqlite3_column_int(stmt, 37));
 
 	return chan;
 }
@@ -665,7 +667,9 @@ static const char *channel_fields =
     "old_per_commit_remote, local_feerate_per_kw, remote_feerate_per_kw, shachain_remote_id, "
     "shutdown_scriptpubkey_remote, shutdown_keyidx_local, "
     "last_sent_commit_state, last_sent_commit_id, "
-    "last_tx, last_sig, last_was_revoke, first_blocknum";
+    "last_tx, last_sig, last_was_revoke, first_blocknum, "
+    " min_possible_feerate, max_possible_feerate";
+
 
 bool wallet_channels_load_active(const tal_t *ctx, struct wallet *w)
 {
@@ -918,7 +922,9 @@ void wallet_channel_save(struct wallet *w, struct channel *chan)
 			  "  shutdown_keyidx_local=?,"
 			  "  channel_config_local=?,"
 			  "  last_tx=?, last_sig=?,"
-			  "  last_was_revoke=?"
+			  "  last_was_revoke=?,"
+			  "  min_possible_feerate=?,"
+			  "  max_possible_feerate=?"
 			  " WHERE id=?");
 	sqlite3_bind_int64(stmt, 1, chan->their_shachain.id);
 	if (chan->scid)
@@ -950,7 +956,9 @@ void wallet_channel_save(struct wallet *w, struct channel *chan)
 	sqlite3_bind_tx(stmt, 19, chan->last_tx);
 	sqlite3_bind_signature(stmt, 20, &chan->last_sig);
 	sqlite3_bind_int(stmt, 21, chan->last_was_revoke);
-	sqlite3_bind_int64(stmt, 22, chan->dbid);
+	sqlite3_bind_int(stmt, 22, chan->min_possible_feerate);
+	sqlite3_bind_int(stmt, 23, chan->max_possible_feerate);
+	sqlite3_bind_int64(stmt, 24, chan->dbid);
 	db_exec_prepared(w->db, stmt);
 
 	wallet_channel_config_save(w, &chan->channel_info.their_config);