lightningd: keep local_basepoints and local_funding_pubkey.

For now we can always regenerate them, but eventually they'll be given
to us by the HSM.

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

lightningd/channel.c

@@ -169,7 +169,9 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    u32 first_blocknum,
 			    u32 min_possible_feerate,
 			    u32 max_possible_feerate,
-			    bool connected)
+			    bool connected,
+			    const struct basepoints *local_basepoints,
+			    const struct pubkey *local_funding_pubkey)
 {
 	struct channel *channel = tal(peer->ld, struct channel);
 
@@ -227,6 +229,8 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 	channel->min_possible_feerate = min_possible_feerate;
 	channel->max_possible_feerate = max_possible_feerate;
 	channel->connected = connected;
+	channel->local_basepoints = *local_basepoints;
+	channel->local_funding_pubkey = *local_funding_pubkey;
 	derive_channel_seed(peer->ld, &channel->seed, &peer->id, channel->dbid);
 
 	list_add_tail(&peer->channels, &channel->list);

lightningd/channel.h

@@ -81,6 +81,12 @@ struct channel {
 	/* Secret seed (FIXME: Move to hsm!) */
 	struct secret seed;
 
+	/* Our local basepoints */
+	struct basepoints local_basepoints;
+
+	/* Our funding tx pubkey. */
+	struct pubkey local_funding_pubkey;
+
 	/* Their scriptpubkey if they sent shutdown. */
 	u8 *remote_shutdown_scriptpubkey;
 	/* Address for any final outputs */
@@ -140,7 +146,9 @@ struct channel *new_channel(struct peer *peer, u64 dbid,
 			    u32 first_blocknum,
 			    u32 min_possible_feerate,
 			    u32 max_possible_feerate,
-			    bool connected);
+			    bool connected,
+			    const struct basepoints *local_basepoints,
+			    const struct pubkey *local_funding_pubkey);
 
 void delete_channel(struct channel *channel);
 

lightningd/opening_control.c

@@ -49,6 +49,12 @@ struct uncommitted_channel {
 	/* Secret seed (FIXME: Move to hsm!) */
 	struct secret seed;
 
+	/* Our basepoints for the channel. */
+	struct basepoints local_basepoints;
+
+	/* Public key for funding tx. */
+	struct pubkey local_funding_pubkey;
+
 	/* Blockheight at creation, scans for funding confirmations
 	 * will start here */
 	u32 first_blocknum;
@@ -238,7 +244,9 @@ wallet_commit_channel(struct lightningd *ld,
 			      uc->first_blocknum,
 			      feerate, feerate,
 			      /* We are connected */
-			      true);
+			      true,
+			      &uc->local_basepoints,
+			      &uc->local_funding_pubkey);
 
 	/* Now we finally put it in the database. */
 	wallet_channel_insert(ld->wallet, channel);
@@ -273,7 +281,6 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 	struct bitcoin_tx *fundingtx;
 	struct bitcoin_txid funding_txid, expected_txid;
 	struct pubkey changekey;
-	struct pubkey local_fundingkey;
 	struct crypto_state cs;
 	secp256k1_ecdsa_signature remote_commit_sig;
 	struct bitcoin_tx *remote_commit;
@@ -321,11 +328,9 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 			     &changekey, fc->wtx.change_key_index))
 		fatal("Error deriving change key %u", fc->wtx.change_key_index);
 
-	derive_basepoints(&fc->uc->seed, &local_fundingkey, NULL, NULL, NULL);
-
 	fundingtx = funding_tx(tmpctx, &funding_outnum,
 			       fc->wtx.utxos, fc->wtx.amount,
-			       &local_fundingkey,
+			       &fc->uc->local_funding_pubkey,
 			       &channel_info.remote_fundingkey,
 			       fc->wtx.change, &changekey,
 			       ld->wallet->bip32_base);
@@ -353,7 +358,7 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 			   fc->wtx.amount,
 			   fc->wtx.change, fc->wtx.change_key_index,
 			   type_to_string(fc, struct pubkey,
-					  &local_fundingkey),
+					  &fc->uc->local_funding_pubkey),
 			   type_to_string(fc, struct pubkey,
 					  &channel_info.remote_fundingkey));
 		command_fail(fc->cmd, JSONRPC2_INVALID_PARAMS,
@@ -364,7 +369,7 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 			     fc->wtx.amount,
 			     fc->wtx.change, fc->wtx.change_key_index,
 			     type_to_string(fc, struct pubkey,
-					    &local_fundingkey),
+					    &fc->uc->local_funding_pubkey),
 			     type_to_string(fc, struct pubkey,
 					    &channel_info.remote_fundingkey));
 		goto failed;
@@ -392,7 +397,7 @@ static void opening_funder_finished(struct subd *openingd, const u8 *resp,
 
 	msg = towire_hsm_sign_funding(tmpctx, channel->funding_satoshi,
 				      fc->wtx.change, fc->wtx.change_key_index,
-				      &local_fundingkey,
+				      &fc->uc->local_funding_pubkey,
 				      &channel_info.remote_fundingkey,
 				      fc->wtx.utxos);
 
@@ -617,7 +622,12 @@ new_uncommitted_channel(struct lightningd *ld,
 	uc->first_blocknum = get_block_height(ld->topology);
 	uc->our_config.id = 0;
 
+	/* FIXME: Keep these in HSM! */
 	derive_channel_seed(ld, &uc->seed, &uc->peer->id, uc->dbid);
+	derive_basepoints(&uc->seed,
+			  &uc->local_funding_pubkey, &uc->local_basepoints,
+			  NULL, NULL);
+
 	uc->peer->uncommitted_channel = uc;
 	tal_add_destructor(uc, destroy_uncommitted_channel);
 

lightningd/peer_control.c

@@ -198,24 +198,22 @@ u32 feerate_max(struct lightningd *ld)
 static void sign_last_tx(struct channel *channel)
 {
 	u8 *funding_wscript;
-	struct pubkey local_funding_pubkey;
 	struct secrets secrets;
 	secp256k1_ecdsa_signature sig;
 
 	assert(!channel->last_tx->input[0].witness);
 
-	derive_basepoints(&channel->seed, &local_funding_pubkey, NULL, &secrets,
-			  NULL);
+	derive_basepoints(&channel->seed, NULL, NULL, &secrets, NULL);
 
 	funding_wscript = bitcoin_redeem_2of2(tmpctx,
-					      &local_funding_pubkey,
+					      &channel->local_funding_pubkey,
 					      &channel->channel_info.remote_fundingkey);
 	/* Need input amount for signing */
 	channel->last_tx->input[0].amount = tal_dup(channel->last_tx->input, u64,
 						    &channel->funding_satoshi);
 	sign_tx_input(channel->last_tx, 0, NULL, funding_wscript,
 		      &secrets.funding_privkey,
-		      &local_funding_pubkey,
+		      &channel->local_funding_pubkey,
 		      &sig);
 
 	channel->last_tx->input[0].witness
@@ -223,7 +221,7 @@ static void sign_last_tx(struct channel *channel)
 				       &channel->last_sig,
 				       &sig,
 				       &channel->channel_info.remote_fundingkey,
-				       &local_funding_pubkey);
+				       &channel->local_funding_pubkey);
 }
 
 static void remove_sig(struct bitcoin_tx *signed_tx)

wallet/test/Makefile

@@ -4,6 +4,7 @@ WALLET_TEST_PROGRAMS := $(WALLET_TEST_OBJS:.o=)
 
 WALLET_TEST_COMMON_OBJS :=			\
 	common/base32.o				\
+	common/derive_basepoints.o		\
 	common/htlc_state.o			\
 	common/type_to_string.o			\
 	common/memleak.o			\

wallet/test/run-wallet.c

@@ -59,13 +59,6 @@ void command_still_pending(struct command *cmd UNNEEDED)
 /* Generated stub for command_success */
 void command_success(struct command *cmd UNNEEDED, struct json_result *response UNNEEDED)
 { fprintf(stderr, "command_success called!\n"); abort(); }
-/* Generated stub for derive_basepoints */
-bool derive_basepoints(const struct secret *seed UNNEEDED,
-		       struct pubkey *funding_pubkey UNNEEDED,
-		       struct basepoints *basepoints UNNEEDED,
-		       struct secrets *secrets UNNEEDED,
-		       struct sha256 *shaseed UNNEEDED)
-{ fprintf(stderr, "derive_basepoints called!\n"); abort(); }
 /* Generated stub for extract_channel_id */
 bool extract_channel_id(const u8 *in_pkt UNNEEDED, struct channel_id *channel_id UNNEEDED)
 { fprintf(stderr, "extract_channel_id called!\n"); abort(); }
@@ -988,6 +981,7 @@ int main(void)
 	struct lightningd *ld;
 
 	setup_tmpctx();
+	secp256k1_ctx = wally_get_secp_context();
 	ld = tal(tmpctx, struct lightningd);
 
 	/* Only elements in ld we should access */

wallet/wallet.c

@@ -564,6 +564,9 @@ static struct channel *wallet_stmt2channel(const tal_t *ctx, struct wallet *w, s
 	u8 *remote_shutdown_scriptpubkey;
 	struct changed_htlc *last_sent_commit;
 	s64 final_key_idx;
+	struct basepoints local_basepoints;
+	struct pubkey local_funding_pubkey;
+	struct secret seed;
 
 	peer_dbid = sqlite3_column_int64(stmt, 1);
 	peer = find_peer_by_dbid(w->ld, peer_dbid);
@@ -623,6 +626,12 @@ static struct channel *wallet_stmt2channel(const tal_t *ctx, struct wallet *w, s
 		log_broken(w->log, "%s: Final key < 0", __func__);
 		return NULL;
 	}
+
+	/* FIXME: this belongs in HSM */
+	derive_channel_seed(w->ld, &seed, &peer->id,
+			    sqlite3_column_int64(stmt, 0));
+	derive_basepoints(&seed, &local_funding_pubkey, &local_basepoints,
+			  NULL, NULL);
 	chan = new_channel(peer, sqlite3_column_int64(stmt, 0),
 			   &wshachain,
 			   sqlite3_column_int(stmt, 5),
@@ -657,7 +666,8 @@ static struct channel *wallet_stmt2channel(const tal_t *ctx, struct wallet *w, s
 			   sqlite3_column_int(stmt, 36),
 			   sqlite3_column_int(stmt, 37),
 			   /* Not connected */
-			   false);
+			   false,
+			   &local_basepoints, &local_funding_pubkey);
 
 	return chan;
 }