channeld: don't keep shachain.

The master daemon is the one which stores it, have it do the check.

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

lightningd/channel/channel.c

@@ -3,7 +3,6 @@
 #include <ccan/cast/cast.h>
 #include <ccan/container_of/container_of.h>
 #include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
-#include <ccan/crypto/shachain/shachain.h>
 #include <ccan/fdpass/fdpass.h>
 #include <ccan/io/io.h>
 #include <ccan/mem/mem.h>
@@ -65,9 +64,6 @@ struct peer {
 	/* Our shaseed for generating per-commitment-secrets. */
 	struct sha256 shaseed;
 
-	/* Their shachain. */
-	struct shachain their_shachain;
-
 	/* BOLT #2:
 	 *
 	 * A sending node MUST set `id` to 0 for the first HTLC it offers, and
@@ -893,23 +889,6 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 					   &peer->old_per_commit[REMOTE]));
 	}
 
-	/* BOLT #2:
-	 *
-	 * A receiving node MAY fail if the `per_commitment_secret` was not
-	 * generated by the protocol in [BOLT #3]
-	 */
-	if (!shachain_add_hash(&peer->their_shachain,
-			       shachain_index(peer->commit_index[REMOTE]),
-			       &old_commit_secret)) {
-		peer_failed(io_conn_fd(peer->peer_conn),
-			    &peer->pcs.cs,
-			    &peer->channel_id,
-			    WIRE_CHANNEL_PEER_BAD_MESSAGE,
-			    "Bad shachain for privkey %"PRIu64" %s ",
-			    peer->commit_index[REMOTE],
-			    type_to_string(msg, struct privkey, &privkey));
-	}
-
 	/* We start timer even if this returns false: we might have delayed
 	 * commit because we were waiting for this! */
 	if (channel_rcvd_revoke_and_ack(peer->channel, &changed_htlcs))
@@ -917,10 +896,6 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 	else
 		status_trace("No commits outstanding after recv revoke_and_ack");
 
-	peer->commit_index[REMOTE]++;
-	peer->old_per_commit[REMOTE] = peer->current_per_commit[REMOTE];
-	peer->current_per_commit[REMOTE] = next_per_commit;
-
 	/* Tell master about things this locks in, wait for response */
 	msg = got_revoke_msg(msg, peer->commit_index[REMOTE],
 			     &old_commit_secret, changed_htlcs);
@@ -928,6 +903,10 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 			  WIRE_CHANNEL_GOT_REVOKE_REPLY,
 			  handle_reply_wake_peer);
 
+	peer->commit_index[REMOTE]++;
+	peer->old_per_commit[REMOTE] = peer->current_per_commit[REMOTE];
+	peer->current_per_commit[REMOTE] = next_per_commit;
+
 	/* And peer waits for reply. */
 	return io_wait(conn, peer, accepted_revocation, peer);
 }
@@ -1648,8 +1627,6 @@ int main(int argc, char *argv[])
 		       sizeof(peer->announcement_bitcoin_sigs[i]));
 	}
 
-	shachain_init(&peer->their_shachain);
-
 	status_setup_async(&peer->master);
 	msg_queue_init(&peer->peer_out, peer);
 

lightningd/peer_control.c

@@ -305,6 +305,7 @@ void add_peer(struct lightningd *ld, u64 unique_id,
 	peer->balance = NULL;
 	peer->state = UNINITIALIZED;
 	peer->channel_info = NULL;
+	shachain_init(&peer->their_shachain);
 
 	idname = type_to_string(peer, struct pubkey, id);
 

lightningd/peer_control.h

@@ -2,6 +2,7 @@
 #define LIGHTNING_LIGHTNINGD_PEER_CONTROL_H
 #include "config.h"
 #include <ccan/compiler/compiler.h>
+#include <ccan/crypto/shachain/shachain.h>
 #include <ccan/list/list.h>
 #include <daemon/htlc.h>
 #include <daemon/json.h>
@@ -23,6 +24,9 @@ struct peer {
 	/* ID of peer */
 	struct pubkey id;
 
+	/* Their shachain. */
+	struct shachain their_shachain;
+
  	/* What's happening. */
  	enum peer_state state;
 

lightningd/peer_htlcs.c

@@ -4,6 +4,7 @@
 #include <daemon/invoice.h>
 #include <daemon/log.h>
 #include <lightningd/channel/gen_channel_wire.h>
+#include <lightningd/derive_basepoints.h>
 #include <lightningd/gossip/gen_gossip_wire.h>
 #include <lightningd/htlc_end.h>
 #include <lightningd/htlc_wire.h>
@@ -908,9 +909,18 @@ int peer_got_commitsig(struct peer *peer, const u8 *msg)
 	return 0;
 }
 
+/* FIXME: add to ccan/shachain */
+static shachain_index_t shachain_next_index(const struct shachain *chain)
+{
+	if (chain->num_valid == 0)
+		return (shachain_index_t)(UINT64_MAX >> (64 - SHACHAIN_BITS));
+	else
+		return chain->min_index - 1;
+}
+	
 int peer_got_revoke(struct peer *peer, const u8 *msg)
 {
-	u64 revokenum;
+	u64 revokenum, shachainidx;
 	struct sha256 per_commitment_secret;
 	u64 *added_ids;
 	struct secret *shared_secret;
@@ -947,7 +957,38 @@ int peer_got_revoke(struct peer *peer, const u8 *msg)
 		}
 	}
 
-	/* FIXME: Save per-commit-secret! */
+	if (revokenum >= (1ULL << 48)) {
+		log_broken(peer->log, "got_revoke: too many txs %"PRIu64,
+			   revokenum);
+		return -1;
+	}
+
+	shachainidx = shachain_index(revokenum);
+	/* Channeld must feed us these in order. */
+	if (shachainidx != shachain_next_index(&peer->their_shachain)) {
+		log_broken(peer->log, "got_revoke: bad revoke number %"PRIu64
+			   " != %"PRIu64,
+			   revokenum,
+			   (u64)281474976710655
+			   - shachain_next_index(&peer->their_shachain));
+		return -1;
+	}
+
+	/* BOLT #2:
+	 *
+	 * A receiving node MAY fail if the `per_commitment_secret` was not
+	 * generated by the protocol in [BOLT #3]
+	 */
+	if (!shachain_add_hash(&peer->their_shachain,
+			       shachainidx, &per_commitment_secret)) {
+		peer_fail(peer, "Bad per_commitment_secret %s for %"PRIu64,
+			  type_to_string(msg, struct sha256,
+					 &per_commitment_secret),
+			  revokenum);
+		return -1;
+	}
+
+	/* FIXME: Commit shachain to db */
 
 	/* Tell it we've committed, and to go ahead with revoke. */
 	msg = towire_channel_got_revoke_reply(msg);