/* Main channel operation daemon: runs from funding_locked to shutdown_complete. * * We're fairly synchronous: our main loop looks for gossip, master or * peer requests and services them synchronously. * * The exceptions are: * 1. When we've asked the master something: in that case, we queue * non-response packets for later processing while we await the reply. * 2. We queue and send non-blocking responses to peers: if both peers were * reading and writing synchronously we could deadlock if we hit buffer * limits, unlikely as that is. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* stdin == requests, 3 == peer, 4 = gossip, 5 = HSM */ #define MASTER_FD STDIN_FILENO #define PEER_FD 3 #define GOSSIP_FD 4 #define HSM_FD 5 struct peer { struct crypto_state cs; bool funding_locked[NUM_SIDES]; u64 next_index[NUM_SIDES]; /* Features peer supports. */ u8 *localfeatures; /* Tolerable amounts for feerate (only relevant for fundee). */ u32 feerate_min, feerate_max; /* Local next per-commit point. */ struct pubkey next_local_per_commit; /* Remote's current per-commit point. */ struct pubkey remote_per_commit; /* Remotes's last per-commitment point: we keep this to check * revoke_and_ack's `per_commitment_secret` is correct. */ struct pubkey old_remote_per_commit; /* Their sig for current commit. */ struct bitcoin_signature their_commit_sig; /* BOLT #2: * * A sending node: *... * - for the first HTLC it offers: * - MUST set `id` to 0. */ u64 htlc_id; struct bitcoin_blkid chain_hash; struct channel_id channel_id; struct channel *channel; /* Messages from master / gossipd: we queue them since we * might be waiting for a specific reply. */ struct msg_queue *from_master, *from_gossipd; struct timers timers; struct oneshot *commit_timer; u64 commit_timer_attempts; u32 commit_msec; /* Are we expecting a pong? */ bool expecting_pong; /* The feerate we want. */ u32 desired_feerate; /* Announcement related information */ struct pubkey node_ids[NUM_SIDES]; struct short_channel_id short_channel_ids[NUM_SIDES]; secp256k1_ecdsa_signature announcement_node_sigs[NUM_SIDES]; secp256k1_ecdsa_signature announcement_bitcoin_sigs[NUM_SIDES]; bool have_sigs[NUM_SIDES]; /* Which direction of the channel do we control? */ u16 channel_direction; /* CLTV delta to announce to peers */ u16 cltv_delta; u32 fee_base; u32 fee_per_satoshi; /* The scriptpubkey to use for shutting down. */ u8 *final_scriptpubkey; /* If master told us to shut down */ bool send_shutdown; /* Has shutdown been sent by each side? */ bool shutdown_sent[NUM_SIDES]; /* Information used for reestablishment. */ bool last_was_revoke; struct changed_htlc *last_sent_commit; u64 revocations_received; u8 channel_flags; bool announce_depth_reached; bool channel_local_active; /* Make sure timestamps move forward. */ u32 last_update_timestamp; /* Make sure peer is live. */ struct timeabs last_recv; }; static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer); static void start_commit_timer(struct peer *peer); static void billboard_update(const struct peer *peer) { const char *funding_status, *announce_status, *shutdown_status; if (peer->funding_locked[LOCAL] && peer->funding_locked[REMOTE]) funding_status = "Funding transaction locked."; else if (!peer->funding_locked[LOCAL] && !peer->funding_locked[REMOTE]) /* FIXME: Say how many blocks to go! */ funding_status = "Funding needs more confirmations."; else if (peer->funding_locked[LOCAL] && !peer->funding_locked[REMOTE]) funding_status = "We've confirmed funding, they haven't yet."; else if (!peer->funding_locked[LOCAL] && peer->funding_locked[REMOTE]) funding_status = "They've confirmed funding, we haven't yet."; if (peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) announce_status = " Channel announced."; else if (peer->have_sigs[LOCAL] && !peer->have_sigs[REMOTE]) announce_status = " Waiting for their announcement signatures."; else if (!peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) announce_status = " They need our announcement signatures."; else if (!peer->have_sigs[LOCAL] && !peer->have_sigs[REMOTE]) announce_status = ""; if (!peer->shutdown_sent[LOCAL] && !peer->shutdown_sent[REMOTE]) shutdown_status = ""; else if (!peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE]) shutdown_status = " We've send shutdown, waiting for theirs"; else if (peer->shutdown_sent[LOCAL] && !peer->shutdown_sent[REMOTE]) shutdown_status = " They've sent shutdown, waiting for ours"; else if (peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE]) { size_t num_htlcs = num_channel_htlcs(peer->channel); if (num_htlcs) shutdown_status = tal_fmt(tmpctx, " Shutdown messages exchanged," " waiting for %zu HTLCs to complete.", num_htlcs); else shutdown_status = tal_fmt(tmpctx, " Shutdown messages exchanged."); } peer_billboard(false, "%s%s%s", funding_status, announce_status, shutdown_status); } static const u8 *hsm_req(const tal_t *ctx, const u8 *req TAKES) { u8 *msg; int type = fromwire_peektype(req); if (!wire_sync_write(HSM_FD, req)) status_failed(STATUS_FAIL_HSM_IO, "Writing %s to HSM: %s", hsm_wire_type_name(type), strerror(errno)); msg = wire_sync_read(ctx, HSM_FD); if (!msg) status_failed(STATUS_FAIL_HSM_IO, "Reading resp to %s: %s", hsm_wire_type_name(type), strerror(errno)); return msg; } /* * The maximum msat that this node will accept for an htlc. * It's flagged as an optional field in `channel_update`. * * We advertise the maximum value possible, defined as the smaller * of the remote's maximum in-flight HTLC or the total channel * capacity minus the cumulative reserve. * FIXME: does this need fuzz? */ static struct amount_msat advertised_htlc_max(const struct channel *channel) { struct amount_sat cumulative_reserve, lower_bound; struct amount_msat lower_bound_msat; /* This shouldn't fail */ if (!amount_sat_add(&cumulative_reserve, channel->config[LOCAL].channel_reserve, channel->config[REMOTE].channel_reserve)) { status_failed(STATUS_FAIL_INTERNAL_ERROR, "reserve overflow: local %s + remote %s", type_to_string(tmpctx, struct amount_sat, &channel->config[LOCAL].channel_reserve), type_to_string(tmpctx, struct amount_sat, &channel->config[REMOTE].channel_reserve)); } /* This shouldn't fail either */ if (!amount_sat_sub(&lower_bound, channel->funding, cumulative_reserve)) { status_failed(STATUS_FAIL_INTERNAL_ERROR, "funding %s - cumulative_reserve %s?", type_to_string(tmpctx, struct amount_sat, &channel->funding), type_to_string(tmpctx, struct amount_sat, &cumulative_reserve)); } if (!amount_sat_to_msat(&lower_bound_msat, lower_bound)) { status_failed(STATUS_FAIL_INTERNAL_ERROR, "lower_bound %s invalid?", type_to_string(tmpctx, struct amount_sat, &lower_bound)); } /* FIXME BOLT QUOTE: https://github.com/lightningnetwork/lightning-rfc/pull/512 once merged */ if (amount_msat_greater(lower_bound_msat, channel->chainparams->max_payment)) lower_bound_msat = channel->chainparams->max_payment; return lower_bound_msat; } /* Create and send channel_update to gossipd (and maybe peer) */ static void send_channel_update(struct peer *peer, int disable_flag) { u8 *msg; assert(disable_flag == 0 || disable_flag == ROUTING_FLAGS_DISABLED); /* Only send an update if we told gossipd */ if (!peer->channel_local_active) return; assert(peer->short_channel_ids[LOCAL].u64); msg = towire_gossipd_local_channel_update(NULL, &peer->short_channel_ids[LOCAL], disable_flag == ROUTING_FLAGS_DISABLED, peer->cltv_delta, peer->channel->config[REMOTE].htlc_minimum, peer->fee_base, peer->fee_per_satoshi, advertised_htlc_max(peer->channel)); wire_sync_write(GOSSIP_FD, take(msg)); } /** * Add a channel locally and send a channel update to the peer * * Send a local_add_channel message to gossipd in order to make the channel * usable locally, and also tell our peer about our parameters via a * channel_update message. The peer may accept the update and use the contained * information to route incoming payments through the channel. The * channel_update is not preceeded by a channel_announcement and won't make much * sense to other nodes, so we don't tell gossipd about it. */ static void make_channel_local_active(struct peer *peer) { u8 *msg; /* Tell gossipd about local channel. */ msg = towire_gossipd_local_add_channel(NULL, &peer->short_channel_ids[LOCAL], &peer->node_ids[REMOTE], peer->channel->funding); wire_sync_write(GOSSIP_FD, take(msg)); /* Tell gossipd and the other side what parameters we expect should * they route through us */ send_channel_update(peer, 0); } static void send_announcement_signatures(struct peer *peer) { /* First 2 + 256 byte are the signatures and msg type, skip them */ size_t offset = 258; struct sha256_double hash; const u8 *msg, *ca, *req; status_trace("Exchanging announcement signatures."); ca = create_channel_announcement(tmpctx, peer); req = towire_hsm_cannouncement_sig_req(tmpctx, ca); msg = hsm_req(tmpctx, req); if (!fromwire_hsm_cannouncement_sig_reply(msg, &peer->announcement_node_sigs[LOCAL], &peer->announcement_bitcoin_sigs[LOCAL])) status_failed(STATUS_FAIL_HSM_IO, "Reading cannouncement_sig_resp: %s", strerror(errno)); /* Double-check that HSM gave valid signatures. */ sha256_double(&hash, ca + offset, tal_count(ca) - offset); if (!check_signed_hash(&hash, &peer->announcement_node_sigs[LOCAL], &peer->node_ids[LOCAL])) { /* It's ok to fail here, the channel announcement is * unique, unlike the channel update which may have * been replaced in the meantime. */ status_failed(STATUS_FAIL_HSM_IO, "HSM returned an invalid node signature"); } if (!check_signed_hash(&hash, &peer->announcement_bitcoin_sigs[LOCAL], &peer->channel->funding_pubkey[LOCAL])) { /* It's ok to fail here, the channel announcement is * unique, unlike the channel update which may have * been replaced in the meantime. */ status_failed(STATUS_FAIL_HSM_IO, "HSM returned an invalid bitcoin signature"); } msg = towire_announcement_signatures( NULL, &peer->channel_id, &peer->short_channel_ids[LOCAL], &peer->announcement_node_sigs[LOCAL], &peer->announcement_bitcoin_sigs[LOCAL]); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } /* Tentatively create a channel_announcement, possibly with invalid * signatures. The signatures need to be collected first, by asking * the HSM and by exchanging announcement_signature messages. */ static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer) { int first, second; u8 *cannounce, *features = tal_arr(ctx, u8, 0); if (peer->channel_direction == 0) { first = LOCAL; second = REMOTE; } else { first = REMOTE; second = LOCAL; } cannounce = towire_channel_announcement( ctx, &peer->announcement_node_sigs[first], &peer->announcement_node_sigs[second], &peer->announcement_bitcoin_sigs[first], &peer->announcement_bitcoin_sigs[second], features, &peer->chain_hash, &peer->short_channel_ids[LOCAL], &peer->node_ids[first], &peer->node_ids[second], &peer->channel->funding_pubkey[first], &peer->channel->funding_pubkey[second]); tal_free(features); return cannounce; } /* Once we have both, we'd better make sure we agree what they are! */ static void check_short_ids_match(struct peer *peer) { assert(peer->have_sigs[LOCAL]); assert(peer->have_sigs[REMOTE]); if (!short_channel_id_eq(&peer->short_channel_ids[LOCAL], &peer->short_channel_ids[REMOTE])) peer_failed(&peer->cs, &peer->channel_id, "We disagree on short_channel_ids:" " I have %s, you say %s", type_to_string(peer, struct short_channel_id, &peer->short_channel_ids[LOCAL]), type_to_string(peer, struct short_channel_id, &peer->short_channel_ids[REMOTE])); } static void announce_channel(struct peer *peer) { u8 *cannounce; check_short_ids_match(peer); cannounce = create_channel_announcement(tmpctx, peer); wire_sync_write(GOSSIP_FD, cannounce); send_channel_update(peer, 0); } static void channel_announcement_negotiate(struct peer *peer) { /* Don't do any announcement work if we're shutting down */ if (peer->shutdown_sent[LOCAL]) return; /* Can't do anything until funding is locked. */ if (!peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) return; if (!peer->channel_local_active) { peer->channel_local_active = true; make_channel_local_active(peer); } /* BOLT #7: * * A node: * - if the `open_channel` message has the `announce_channel` bit set AND a `shutdown` message has not been sent: * - MUST send the `announcement_signatures` message. * - MUST NOT send `announcement_signatures` messages until `funding_locked` * has been sent and received AND the funding transaction has at least six confirmations. * - otherwise: * - MUST NOT send the `announcement_signatures` message. */ if (!(peer->channel_flags & CHANNEL_FLAGS_ANNOUNCE_CHANNEL)) return; /* BOLT #7: * * - MUST NOT send `announcement_signatures` messages until `funding_locked` * has been sent and received AND the funding transaction has at least six confirmations. */ if (peer->announce_depth_reached && !peer->have_sigs[LOCAL]) { send_announcement_signatures(peer); peer->have_sigs[LOCAL] = true; billboard_update(peer); } /* If we've completed the signature exchange, we can send a real * announcement, otherwise we send a temporary one */ if (peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) announce_channel(peer); } static void handle_peer_funding_locked(struct peer *peer, const u8 *msg) { struct channel_id chanid; /* BOLT #2: * * A node: *... * - upon reconnection: * - MUST ignore any redundant `funding_locked` it receives. */ if (peer->funding_locked[REMOTE]) return; /* Too late, we're shutting down! */ if (peer->shutdown_sent[LOCAL]) return; peer->old_remote_per_commit = peer->remote_per_commit; if (!fromwire_funding_locked(msg, &chanid, &peer->remote_per_commit)) peer_failed(&peer->cs, &peer->channel_id, "Bad funding_locked %s", tal_hex(msg, msg)); if (!channel_id_eq(&chanid, &peer->channel_id)) peer_failed(&peer->cs, &peer->channel_id, "Wrong channel id in %s (expected %s)", tal_hex(tmpctx, msg), type_to_string(msg, struct channel_id, &peer->channel_id)); peer->funding_locked[REMOTE] = true; wire_sync_write(MASTER_FD, take(towire_channel_got_funding_locked(NULL, &peer->remote_per_commit))); channel_announcement_negotiate(peer); billboard_update(peer); } static void handle_peer_announcement_signatures(struct peer *peer, const u8 *msg) { struct channel_id chanid; if (!fromwire_announcement_signatures(msg, &chanid, &peer->short_channel_ids[REMOTE], &peer->announcement_node_sigs[REMOTE], &peer->announcement_bitcoin_sigs[REMOTE])) peer_failed(&peer->cs, &peer->channel_id, "Bad announcement_signatures %s", tal_hex(msg, msg)); /* Make sure we agree on the channel ids */ if (!channel_id_eq(&chanid, &peer->channel_id)) { peer_failed(&peer->cs, &peer->channel_id, "Wrong channel_id: expected %s, got %s", type_to_string(tmpctx, struct channel_id, &peer->channel_id), type_to_string(tmpctx, struct channel_id, &chanid)); } peer->have_sigs[REMOTE] = true; billboard_update(peer); channel_announcement_negotiate(peer); } static struct secret *get_shared_secret(const tal_t *ctx, const struct htlc *htlc, enum onion_type *why_bad, struct sha256 *next_onion_sha) { struct onionpacket *op; struct secret *secret = tal(ctx, struct secret); const u8 *msg; struct route_step *rs; /* We unwrap the onion now. */ op = parse_onionpacket(tmpctx, htlc->routing, TOTAL_PACKET_SIZE, why_bad); if (!op) return tal_free(secret); /* Because wire takes struct pubkey. */ msg = hsm_req(tmpctx, towire_hsm_ecdh_req(tmpctx, &op->ephemeralkey)); if (!fromwire_hsm_ecdh_resp(msg, secret)) status_failed(STATUS_FAIL_HSM_IO, "Reading ecdh response"); /* We make sure we can parse onion packet, so we know if shared secret * is actually valid (this checks hmac). */ rs = process_onionpacket(tmpctx, op, secret->data, htlc->rhash.u.u8, sizeof(htlc->rhash)); if (!rs) { *why_bad = WIRE_INVALID_ONION_HMAC; return tal_free(secret); } /* Calculate sha256 we'll hand to next peer, in case they complain. */ msg = serialize_onionpacket(tmpctx, rs->next); sha256(next_onion_sha, msg, tal_bytelen(msg)); return secret; } static void handle_peer_add_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; struct amount_msat amount; u32 cltv_expiry; struct sha256 payment_hash; u8 onion_routing_packet[TOTAL_PACKET_SIZE]; enum channel_add_err add_err; struct htlc *htlc; if (!fromwire_update_add_htlc(msg, &channel_id, &id, &amount, &payment_hash, &cltv_expiry, onion_routing_packet)) peer_failed(&peer->cs, &peer->channel_id, "Bad peer_add_htlc %s", tal_hex(msg, msg)); add_err = channel_add_htlc(peer->channel, REMOTE, id, amount, cltv_expiry, &payment_hash, onion_routing_packet, &htlc); if (add_err != CHANNEL_ERR_ADD_OK) peer_failed(&peer->cs, &peer->channel_id, "Bad peer_add_htlc: %s", channel_add_err_name(add_err)); /* If this is wrong, we don't complain yet; when it's confirmed we'll * send it to the master which handles all HTLC failures. */ htlc->shared_secret = get_shared_secret(htlc, htlc, &htlc->why_bad_onion, &htlc->next_onion_sha); } static void handle_peer_feechange(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u32 feerate; if (!fromwire_update_fee(msg, &channel_id, &feerate)) { peer_failed(&peer->cs, &peer->channel_id, "Bad update_fee %s", tal_hex(msg, msg)); } /* BOLT #2: * * A receiving node: *... * - if the sender is not responsible for paying the Bitcoin fee: * - MUST fail the channel. */ if (peer->channel->funder != REMOTE) peer_failed(&peer->cs, &peer->channel_id, "update_fee from non-funder?"); status_trace("update_fee %u, range %u-%u", feerate, peer->feerate_min, peer->feerate_max); /* BOLT #2: * * A receiving node: * - if the `update_fee` is too low for timely processing, OR is * unreasonably large: * - SHOULD fail the channel. */ if (feerate < peer->feerate_min || feerate > peer->feerate_max) peer_failed(&peer->cs, &peer->channel_id, "update_fee %u outside range %u-%u", feerate, peer->feerate_min, peer->feerate_max); /* BOLT #2: * * - if the sender cannot afford the new fee rate on the receiving * node's current commitment transaction: * - SHOULD fail the channel, * - but MAY delay this check until the `update_fee` is committed. */ if (!channel_update_feerate(peer->channel, feerate)) peer_failed(&peer->cs, &peer->channel_id, "update_fee %u unaffordable", feerate); status_trace("peer updated fee to %u", feerate); } static struct changed_htlc *changed_htlc_arr(const tal_t *ctx, const struct htlc **changed_htlcs) { struct changed_htlc *changed; size_t i; changed = tal_arr(ctx, struct changed_htlc, tal_count(changed_htlcs)); for (i = 0; i < tal_count(changed_htlcs); i++) { changed[i].id = changed_htlcs[i]->id; changed[i].newstate = changed_htlcs[i]->state; } return changed; } static u8 *sending_commitsig_msg(const tal_t *ctx, u64 remote_commit_index, u32 remote_feerate, const struct htlc **changed_htlcs, const struct bitcoin_signature *commit_sig, const secp256k1_ecdsa_signature *htlc_sigs) { struct changed_htlc *changed; u8 *msg; /* We tell master what (of our) HTLCs peer will now be * committed to. */ changed = changed_htlc_arr(tmpctx, changed_htlcs); msg = towire_channel_sending_commitsig(ctx, remote_commit_index, remote_feerate, changed, commit_sig, htlc_sigs); return msg; } static bool shutdown_complete(const struct peer *peer) { return peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE] && num_channel_htlcs(peer->channel) == 0 /* We could be awaiting revoke-and-ack for a feechange */ && peer->revocations_received == peer->next_index[REMOTE] - 1; } /* BOLT #2: * * A sending node: *... * - if there are updates pending on the receiving node's commitment * transaction: * - MUST NOT send a `shutdown`. */ /* So we only call this after reestablish or immediately after sending commit */ static void maybe_send_shutdown(struct peer *peer) { u8 *msg; if (!peer->send_shutdown) return; /* Send a disable channel_update so others don't try to route * over us */ send_channel_update(peer, ROUTING_FLAGS_DISABLED); msg = towire_shutdown(NULL, &peer->channel_id, peer->final_scriptpubkey); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); peer->send_shutdown = false; peer->shutdown_sent[LOCAL] = true; billboard_update(peer); } /* This queues other traffic from the fd until we get reply. */ static u8 *wait_sync_reply(const tal_t *ctx, const u8 *msg, int replytype, int fd, struct msg_queue *queue, const char *who) { u8 *reply; status_trace("Sending %s %u", who, fromwire_peektype(msg)); if (!wire_sync_write(fd, msg)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync write to %s: %s", who, strerror(errno)); status_trace("... , awaiting %u", replytype); for (;;) { reply = wire_sync_read(ctx, fd); if (!reply) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync read from %s: %s", who, strerror(errno)); if (fromwire_peektype(reply) == replytype) { status_trace("Got it!"); break; } status_trace("Nope, got %u instead", fromwire_peektype(reply)); msg_enqueue(queue, take(reply)); } return reply; } static u8 *master_wait_sync_reply(const tal_t *ctx, struct peer *peer, const u8 *msg, enum channel_wire_type replytype) { return wait_sync_reply(ctx, msg, replytype, MASTER_FD, peer->from_master, "master"); } static u8 *gossipd_wait_sync_reply(const tal_t *ctx, struct peer *peer, const u8 *msg, enum gossip_peerd_wire_type replytype) { return wait_sync_reply(ctx, msg, replytype, GOSSIP_FD, peer->from_gossipd, "gossipd"); } static u8 *foreign_channel_update(const tal_t *ctx, struct peer *peer, const struct short_channel_id *scid) { u8 *msg, *update, *channel_update; msg = towire_gossipd_get_update(NULL, scid); msg = gossipd_wait_sync_reply(tmpctx, peer, take(msg), WIRE_GOSSIPD_GET_UPDATE_REPLY); if (!fromwire_gossipd_get_update_reply(ctx, msg, &update)) status_failed(STATUS_FAIL_GOSSIP_IO, "Invalid update reply"); /* Strip the type from the channel_update. Due to the specification * being underspecified, some implementations skipped the type * prefix. Since we are in the minority we adapt (See #1730 and * lightningnetwork/lnd#1599 for details). */ if (update && fromwire_peektype(update) == WIRE_CHANNEL_UPDATE) { assert(tal_bytelen(update) > 2); channel_update = tal_arr(ctx, u8, 0); towire(&channel_update, update + 2, tal_bytelen(update) - 2); tal_free(update); return channel_update; } else { return update; } } static u8 *make_failmsg(const tal_t *ctx, struct peer *peer, const struct htlc *htlc, enum onion_type failcode, const struct short_channel_id *scid, const struct sha256 *sha256) { u8 *msg, *channel_update = NULL; u32 cltv_expiry = abs_locktime_to_blocks(&htlc->expiry); switch (failcode) { case WIRE_INVALID_REALM: msg = towire_invalid_realm(ctx); goto done; case WIRE_TEMPORARY_NODE_FAILURE: msg = towire_temporary_node_failure(ctx); goto done; case WIRE_PERMANENT_NODE_FAILURE: msg = towire_permanent_node_failure(ctx); goto done; case WIRE_REQUIRED_NODE_FEATURE_MISSING: msg = towire_required_node_feature_missing(ctx); goto done; case WIRE_TEMPORARY_CHANNEL_FAILURE: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_temporary_channel_failure(ctx, channel_update); goto done; case WIRE_CHANNEL_DISABLED: msg = towire_channel_disabled(ctx); goto done; case WIRE_PERMANENT_CHANNEL_FAILURE: msg = towire_permanent_channel_failure(ctx); goto done; case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING: msg = towire_required_channel_feature_missing(ctx); goto done; case WIRE_UNKNOWN_NEXT_PEER: msg = towire_unknown_next_peer(ctx); goto done; case WIRE_AMOUNT_BELOW_MINIMUM: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_amount_below_minimum(ctx, htlc->amount, channel_update); goto done; case WIRE_FEE_INSUFFICIENT: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_fee_insufficient(ctx, htlc->amount, channel_update); goto done; case WIRE_INCORRECT_CLTV_EXPIRY: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_incorrect_cltv_expiry(ctx, cltv_expiry, channel_update); goto done; case WIRE_EXPIRY_TOO_SOON: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_expiry_too_soon(ctx, channel_update); goto done; case WIRE_EXPIRY_TOO_FAR: msg = towire_expiry_too_far(ctx); goto done; case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS: msg = towire_incorrect_or_unknown_payment_details( ctx, htlc->amount); goto done; case WIRE_FINAL_EXPIRY_TOO_SOON: msg = towire_final_expiry_too_soon(ctx); goto done; case WIRE_FINAL_INCORRECT_CLTV_EXPIRY: msg = towire_final_incorrect_cltv_expiry(ctx, cltv_expiry); goto done; case WIRE_FINAL_INCORRECT_HTLC_AMOUNT: msg = towire_final_incorrect_htlc_amount(ctx, htlc->amount); goto done; case WIRE_INVALID_ONION_VERSION: msg = towire_invalid_onion_version(ctx, sha256); goto done; case WIRE_INVALID_ONION_HMAC: msg = towire_invalid_onion_hmac(ctx, sha256); goto done; case WIRE_INVALID_ONION_KEY: msg = towire_invalid_onion_key(ctx, sha256); goto done; case WIRE_INCORRECT_PAYMENT_AMOUNT: /* Deprecated: we should never make this any more! */ break; } status_failed(STATUS_FAIL_INTERNAL_ERROR, "Asked to create failmsg %u (%s)", failcode, onion_type_name(failcode)); done: tal_free(channel_update); return msg; } /* Returns HTLC sigs, sets commit_sig */ static secp256k1_ecdsa_signature *calc_commitsigs(const tal_t *ctx, const struct peer *peer, u64 commit_index, struct bitcoin_signature *commit_sig) { size_t i; struct bitcoin_tx **txs; const u8 **wscripts; const struct htlc **htlc_map; struct pubkey local_htlckey; const u8 *msg; secp256k1_ecdsa_signature *htlc_sigs; txs = channel_txs(tmpctx, &htlc_map, &wscripts, peer->channel, &peer->remote_per_commit, commit_index, REMOTE); msg = towire_hsm_sign_remote_commitment_tx(NULL, txs[0], &peer->channel->funding_pubkey[REMOTE], *txs[0]->input[0].amount); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsm_sign_tx_reply(msg, commit_sig)) status_failed(STATUS_FAIL_HSM_IO, "Reading sign_remote_commitment_tx reply: %s", tal_hex(tmpctx, msg)); status_trace("Creating commit_sig signature %"PRIu64" %s for tx %s wscript %s key %s", commit_index, type_to_string(tmpctx, struct bitcoin_signature, commit_sig), type_to_string(tmpctx, struct bitcoin_tx, txs[0]), tal_hex(tmpctx, wscripts[0]), type_to_string(tmpctx, struct pubkey, &peer->channel->funding_pubkey[LOCAL])); dump_htlcs(peer->channel, "Sending commit_sig"); if (!derive_simple_key(&peer->channel->basepoints[LOCAL].htlc, &peer->remote_per_commit, &local_htlckey)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving local_htlckey"); /* BOLT #2: * * A sending node: *... * - MUST include one `htlc_signature` for every HTLC transaction * corresponding to BIP69 lexicographic ordering of the commitment * transaction. */ htlc_sigs = tal_arr(ctx, secp256k1_ecdsa_signature, tal_count(txs) - 1); for (i = 0; i < tal_count(htlc_sigs); i++) { struct bitcoin_signature sig; msg = towire_hsm_sign_remote_htlc_tx(NULL, txs[i + 1], wscripts[i + 1], *txs[i+1]->input[0].amount, &peer->remote_per_commit); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsm_sign_tx_reply(msg, &sig)) status_failed(STATUS_FAIL_HSM_IO, "Bad sign_remote_htlc_tx reply: %s", tal_hex(tmpctx, msg)); htlc_sigs[i] = sig.s; status_trace("Creating HTLC signature %s for tx %s wscript %s key %s", type_to_string(tmpctx, struct bitcoin_signature, &sig), type_to_string(tmpctx, struct bitcoin_tx, txs[1+i]), tal_hex(tmpctx, wscripts[1+i]), type_to_string(tmpctx, struct pubkey, &local_htlckey)); assert(check_tx_sig(txs[1+i], 0, NULL, wscripts[1+i], &local_htlckey, &sig)); } return htlc_sigs; } /* Have we received something from peer recently? */ static bool peer_recently_active(struct peer *peer) { return time_less(time_between(time_now(), peer->last_recv), time_from_sec(30)); } static void maybe_send_ping(struct peer *peer) { /* Already have a ping in flight? */ if (peer->expecting_pong) return; if (peer_recently_active(peer)) return; /* Send a ping to try to elicit a receive. */ sync_crypto_write_no_delay(&peer->cs, PEER_FD, take(make_ping(NULL, 1, 0))); peer->expecting_pong = true; } static void send_commit(struct peer *peer) { u8 *msg; const struct htlc **changed_htlcs; struct bitcoin_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; #if DEVELOPER /* Hack to suppress all commit sends if dev_disconnect says to */ if (dev_suppress_commit) { peer->commit_timer = NULL; return; } #endif /* FIXME: Document this requirement in BOLT 2! */ /* We can't send two commits in a row. */ if (peer->revocations_received != peer->next_index[REMOTE] - 1) { assert(peer->revocations_received == peer->next_index[REMOTE] - 2); peer->commit_timer_attempts++; /* Only report this in extreme cases */ if (peer->commit_timer_attempts % 100 == 0) status_trace("Can't send commit:" " waiting for revoke_and_ack with %" PRIu64" attempts", peer->commit_timer_attempts); /* Mark this as done and try again. */ peer->commit_timer = NULL; start_commit_timer(peer); return; } /* BOLT #2: * * - if no HTLCs remain in either commitment transaction: * - MUST NOT send any `update` message after a `shutdown`. */ if (peer->shutdown_sent[LOCAL] && !num_channel_htlcs(peer->channel)) { status_trace("Can't send commit: final shutdown phase"); peer->commit_timer = NULL; return; } /* If we haven't received a packet for > 30 seconds, delay. */ if (!peer_recently_active(peer)) { /* Mark this as done and try again. */ peer->commit_timer = NULL; start_commit_timer(peer); return; } /* If we wanted to update fees, do it now. */ if (peer->channel->funder == LOCAL && peer->desired_feerate != channel_feerate(peer->channel, REMOTE)) { u8 *msg; u32 feerate, max = approx_max_feerate(peer->channel); feerate = peer->desired_feerate; /* FIXME: We should avoid adding HTLCs until we can meet this * feerate! */ if (feerate > max) feerate = max; if (!channel_update_feerate(peer->channel, feerate)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not afford feerate %u" " (vs max %u)", feerate, max); msg = towire_update_fee(NULL, &peer->channel_id, feerate); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } /* BOLT #2: * * A sending node: * - MUST NOT send a `commitment_signed` message that does not include * any updates. */ changed_htlcs = tal_arr(tmpctx, const struct htlc *, 0); if (!channel_sending_commit(peer->channel, &changed_htlcs)) { status_trace("Can't send commit: nothing to send"); /* Covers the case where we've just been told to shutdown. */ maybe_send_shutdown(peer); peer->commit_timer = NULL; return; } htlc_sigs = calc_commitsigs(tmpctx, peer, peer->next_index[REMOTE], &commit_sig); status_trace("Telling master we're about to commit..."); /* Tell master to save this next commit to database, then wait. */ msg = sending_commitsig_msg(NULL, peer->next_index[REMOTE], channel_feerate(peer->channel, REMOTE), changed_htlcs, &commit_sig, htlc_sigs); /* Message is empty; receiving it is the point. */ master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_SENDING_COMMITSIG_REPLY); status_trace("Sending commit_sig with %zu htlc sigs", tal_count(htlc_sigs)); peer->next_index[REMOTE]++; msg = towire_commitment_signed(NULL, &peer->channel_id, &commit_sig.s, htlc_sigs); sync_crypto_write_no_delay(&peer->cs, PEER_FD, take(msg)); maybe_send_shutdown(peer); /* Timer now considered expired, you can add a new one. */ peer->commit_timer = NULL; start_commit_timer(peer); } static void start_commit_timer(struct peer *peer) { /* We should send a ping now if we need a liveness check. */ maybe_send_ping(peer); /* Already armed? */ if (peer->commit_timer) return; peer->commit_timer_attempts = 0; peer->commit_timer = new_reltimer(&peer->timers, peer, time_from_msec(peer->commit_msec), send_commit, peer); } /* If old_secret is NULL, we don't care, otherwise it is filled in. */ static void get_per_commitment_point(u64 index, struct pubkey *point, struct secret *old_secret) { struct secret *s; const u8 *msg; msg = hsm_req(tmpctx, take(towire_hsm_get_per_commitment_point(NULL, index))); if (!fromwire_hsm_get_per_commitment_point_reply(tmpctx, msg, point, &s)) status_failed(STATUS_FAIL_HSM_IO, "Bad per_commitment_point reply %s", tal_hex(tmpctx, msg)); if (old_secret) { if (!s) status_failed(STATUS_FAIL_HSM_IO, "No secret in per_commitment_point_reply %" PRIu64, index); *old_secret = *s; } } /* revoke_index == current index - 1 (usually; not for retransmission) */ static u8 *make_revocation_msg(const struct peer *peer, u64 revoke_index, struct pubkey *point) { struct secret old_commit_secret; get_per_commitment_point(revoke_index+2, point, &old_commit_secret); return towire_revoke_and_ack(peer, &peer->channel_id, &old_commit_secret, point); } static void send_revocation(struct peer *peer) { /* Revoke previous commit, get new point. */ u8 *msg = make_revocation_msg(peer, peer->next_index[LOCAL]-1, &peer->next_local_per_commit); /* From now on we apply changes to the next commitment */ peer->next_index[LOCAL]++; /* If this queues more changes on the other end, send commit. */ if (channel_sending_revoke_and_ack(peer->channel)) { status_trace("revoke_and_ack made pending: commit timer"); start_commit_timer(peer); } sync_crypto_write_no_delay(&peer->cs, PEER_FD, take(msg)); } static u8 *got_commitsig_msg(const tal_t *ctx, u64 local_commit_index, u32 local_feerate, const struct bitcoin_signature *commit_sig, const secp256k1_ecdsa_signature *htlc_sigs, const struct htlc **changed_htlcs, const struct bitcoin_tx *committx) { struct changed_htlc *changed; struct fulfilled_htlc *fulfilled; const struct failed_htlc **failed; struct added_htlc *added; struct secret *shared_secret; u8 *msg; changed = tal_arr(tmpctx, struct changed_htlc, 0); added = tal_arr(tmpctx, struct added_htlc, 0); shared_secret = tal_arr(tmpctx, struct secret, 0); failed = tal_arr(tmpctx, const struct failed_htlc *, 0); fulfilled = tal_arr(tmpctx, struct fulfilled_htlc, 0); for (size_t i = 0; i < tal_count(changed_htlcs); i++) { const struct htlc *htlc = changed_htlcs[i]; if (htlc->state == RCVD_ADD_COMMIT) { struct added_htlc a; struct secret s; a.id = htlc->id; a.amount = htlc->amount; a.payment_hash = htlc->rhash; a.cltv_expiry = abs_locktime_to_blocks(&htlc->expiry); memcpy(a.onion_routing_packet, htlc->routing, sizeof(a.onion_routing_packet)); /* Invalid shared secret gets set to all-zero: our * code generator can't make arrays of optional values */ if (!htlc->shared_secret) memset(&s, 0, sizeof(s)); else s = *htlc->shared_secret; tal_arr_expand(&added, a); tal_arr_expand(&shared_secret, s); } else if (htlc->state == RCVD_REMOVE_COMMIT) { if (htlc->r) { struct fulfilled_htlc f; assert(!htlc->fail && !htlc->failcode); f.id = htlc->id; f.payment_preimage = *htlc->r; tal_arr_expand(&fulfilled, f); } else { struct failed_htlc *f; assert(htlc->fail || htlc->failcode); f = tal(failed, struct failed_htlc); f->id = htlc->id; f->failcode = htlc->failcode; f->failreason = cast_const(u8 *, htlc->fail); f->scid = cast_const(struct short_channel_id *, htlc->failed_scid); tal_arr_expand(&failed, f); } } else { struct changed_htlc c; assert(htlc->state == RCVD_REMOVE_ACK_COMMIT || htlc->state == RCVD_ADD_ACK_COMMIT); c.id = htlc->id; c.newstate = htlc->state; tal_arr_expand(&changed, c); } } msg = towire_channel_got_commitsig(ctx, local_commit_index, local_feerate, commit_sig, htlc_sigs, added, shared_secret, fulfilled, failed, changed, committx); return msg; } static void handle_peer_commit_sig(struct peer *peer, const u8 *msg) { struct channel_id channel_id; struct bitcoin_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; struct pubkey remote_htlckey; struct bitcoin_tx **txs; const struct htlc **htlc_map, **changed_htlcs; const u8 **wscripts; size_t i; changed_htlcs = tal_arr(msg, const struct htlc *, 0); if (!channel_rcvd_commit(peer->channel, &changed_htlcs)) { /* BOLT #2: * * A sending node: * - MUST NOT send a `commitment_signed` message that does not * include any updates. */ peer_failed(&peer->cs, &peer->channel_id, "commit_sig with no changes"); } /* We were supposed to check this was affordable as we go. */ if (peer->channel->funder == REMOTE) assert(can_funder_afford_feerate(peer->channel, peer->channel->view[LOCAL] .feerate_per_kw)); if (!fromwire_commitment_signed(tmpctx, msg, &channel_id, &commit_sig.s, &htlc_sigs)) peer_failed(&peer->cs, &peer->channel_id, "Bad commit_sig %s", tal_hex(msg, msg)); /* SIGHASH_ALL is implied. */ commit_sig.sighash_type = SIGHASH_ALL; txs = channel_txs(tmpctx, &htlc_map, &wscripts, peer->channel, &peer->next_local_per_commit, peer->next_index[LOCAL], LOCAL); if (!derive_simple_key(&peer->channel->basepoints[REMOTE].htlc, &peer->next_local_per_commit, &remote_htlckey)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving remote_htlckey"); status_trace("Derived key %s from basepoint %s, point %s", type_to_string(tmpctx, struct pubkey, &remote_htlckey), type_to_string(tmpctx, struct pubkey, &peer->channel->basepoints[REMOTE].htlc), type_to_string(tmpctx, struct pubkey, &peer->next_local_per_commit)); /* BOLT #2: * * A receiving node: * - once all pending updates are applied: * - if `signature` is not valid for its local commitment transaction: * - MUST fail the channel. */ if (!check_tx_sig(txs[0], 0, NULL, wscripts[0], &peer->channel->funding_pubkey[REMOTE], &commit_sig)) { dump_htlcs(peer->channel, "receiving commit_sig"); peer_failed(&peer->cs, &peer->channel_id, "Bad commit_sig signature %"PRIu64" %s for tx %s wscript %s key %s feerate %u", peer->next_index[LOCAL], type_to_string(msg, struct bitcoin_signature, &commit_sig), type_to_string(msg, struct bitcoin_tx, txs[0]), tal_hex(msg, wscripts[0]), type_to_string(msg, struct pubkey, &peer->channel->funding_pubkey [REMOTE]), peer->channel->view[LOCAL].feerate_per_kw); } /* BOLT #2: * * A receiving node: *... * - if `num_htlcs` is not equal to the number of HTLC outputs in the * local commitment transaction: * - MUST fail the channel. */ if (tal_count(htlc_sigs) != tal_count(txs) - 1) peer_failed(&peer->cs, &peer->channel_id, "Expected %zu htlc sigs, not %zu", tal_count(txs) - 1, tal_count(htlc_sigs)); /* BOLT #2: * * - if any `htlc_signature` is not valid for the corresponding HTLC * transaction: * - MUST fail the channel. */ for (i = 0; i < tal_count(htlc_sigs); i++) { struct bitcoin_signature sig; /* SIGHASH_ALL is implied. */ sig.s = htlc_sigs[i]; sig.sighash_type = SIGHASH_ALL; if (!check_tx_sig(txs[1+i], 0, NULL, wscripts[1+i], &remote_htlckey, &sig)) peer_failed(&peer->cs, &peer->channel_id, "Bad commit_sig signature %s for htlc %s wscript %s key %s", type_to_string(msg, struct bitcoin_signature, &sig), type_to_string(msg, struct bitcoin_tx, txs[1+i]), tal_hex(msg, wscripts[1+i]), type_to_string(msg, struct pubkey, &remote_htlckey)); } status_trace("Received commit_sig with %zu htlc sigs", tal_count(htlc_sigs)); /* Tell master daemon, then wait for ack. */ msg = got_commitsig_msg(NULL, peer->next_index[LOCAL], channel_feerate(peer->channel, LOCAL), &commit_sig, htlc_sigs, changed_htlcs, txs[0]); master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_GOT_COMMITSIG_REPLY); return send_revocation(peer); } static u8 *got_revoke_msg(const tal_t *ctx, u64 revoke_num, const struct secret *per_commitment_secret, const struct pubkey *next_per_commit_point, const struct htlc **changed_htlcs, u32 feerate) { u8 *msg; struct changed_htlc *changed = tal_arr(tmpctx, struct changed_htlc, 0); for (size_t i = 0; i < tal_count(changed_htlcs); i++) { struct changed_htlc c; const struct htlc *htlc = changed_htlcs[i]; status_trace("HTLC %"PRIu64"[%s] => %s", htlc->id, side_to_str(htlc_owner(htlc)), htlc_state_name(htlc->state)); c.id = changed_htlcs[i]->id; c.newstate = changed_htlcs[i]->state; tal_arr_expand(&changed, c); } msg = towire_channel_got_revoke(ctx, revoke_num, per_commitment_secret, next_per_commit_point, feerate, changed); return msg; } static void handle_peer_revoke_and_ack(struct peer *peer, const u8 *msg) { struct secret old_commit_secret; struct privkey privkey; struct channel_id channel_id; struct pubkey per_commit_point, next_per_commit; const struct htlc **changed_htlcs = tal_arr(msg, const struct htlc *, 0); if (!fromwire_revoke_and_ack(msg, &channel_id, &old_commit_secret, &next_per_commit)) { peer_failed(&peer->cs, &peer->channel_id, "Bad revoke_and_ack %s", tal_hex(msg, msg)); } if (peer->revocations_received != peer->next_index[REMOTE] - 2) { peer_failed(&peer->cs, &peer->channel_id, "Unexpected revoke_and_ack"); } /* BOLT #2: * * A receiving node: * - if `per_commitment_secret` does not generate the previous * `per_commitment_point`: * - MUST fail the channel. */ memcpy(&privkey, &old_commit_secret, sizeof(privkey)); if (!pubkey_from_privkey(&privkey, &per_commit_point)) { peer_failed(&peer->cs, &peer->channel_id, "Bad privkey %s", type_to_string(msg, struct privkey, &privkey)); } if (!pubkey_eq(&per_commit_point, &peer->old_remote_per_commit)) { peer_failed(&peer->cs, &peer->channel_id, "Wrong privkey %s for %"PRIu64" %s", type_to_string(msg, struct privkey, &privkey), peer->next_index[LOCAL]-2, type_to_string(msg, struct pubkey, &peer->old_remote_per_commit)); } /* 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)) status_trace("Commits outstanding after recv revoke_and_ack"); else status_trace("No commits outstanding after recv revoke_and_ack"); /* Tell master about things this locks in, wait for response */ msg = got_revoke_msg(NULL, peer->revocations_received++, &old_commit_secret, &next_per_commit, changed_htlcs, channel_feerate(peer->channel, LOCAL)); master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_GOT_REVOKE_REPLY); peer->old_remote_per_commit = peer->remote_per_commit; peer->remote_per_commit = next_per_commit; status_trace("revoke_and_ack %s: remote_per_commit = %s, old_remote_per_commit = %s", side_to_str(peer->channel->funder), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit)); start_commit_timer(peer); } static void handle_peer_fulfill_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; struct preimage preimage; enum channel_remove_err e; struct htlc *h; if (!fromwire_update_fulfill_htlc(msg, &channel_id, &id, &preimage)) { peer_failed(&peer->cs, &peer->channel_id, "Bad update_fulfill_htlc %s", tal_hex(msg, msg)); } e = channel_fulfill_htlc(peer->channel, LOCAL, id, &preimage, &h); switch (e) { case CHANNEL_ERR_REMOVE_OK: /* FIXME: We could send preimages to master immediately. */ start_commit_timer(peer); return; /* These shouldn't happen, because any offered HTLC (which would give * us the preimage) should have timed out long before. If we * were to get preimages from other sources, this could happen. */ case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, &peer->channel_id, "Bad update_fulfill_htlc: failed to fulfill %" PRIu64 " error %s", id, channel_remove_err_name(e)); } abort(); } static void handle_peer_fail_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; enum channel_remove_err e; u8 *reason; struct htlc *htlc; if (!fromwire_update_fail_htlc(msg, msg, &channel_id, &id, &reason)) { peer_failed(&peer->cs, &peer->channel_id, "Bad update_fail_htlc %s", tal_hex(msg, msg)); } e = channel_fail_htlc(peer->channel, LOCAL, id, &htlc); switch (e) { case CHANNEL_ERR_REMOVE_OK: /* Save reason for when we tell master. */ htlc->fail = tal_steal(htlc, reason); start_commit_timer(peer); return; case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, &peer->channel_id, "Bad update_fail_htlc: failed to remove %" PRIu64 " error %s", id, channel_remove_err_name(e)); } abort(); } static void handle_peer_fail_malformed_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; enum channel_remove_err e; struct sha256 sha256_of_onion; u16 failure_code; struct htlc *htlc; if (!fromwire_update_fail_malformed_htlc(msg, &channel_id, &id, &sha256_of_onion, &failure_code)) { peer_failed(&peer->cs, &peer->channel_id, "Bad update_fail_malformed_htlc %s", tal_hex(msg, msg)); } /* BOLT #2: * * - if the `BADONION` bit in `failure_code` is not set for * `update_fail_malformed_htlc`: * - MUST fail the channel. */ if (!(failure_code & BADONION)) { peer_failed(&peer->cs, &peer->channel_id, "Bad update_fail_malformed_htlc failure code %u", failure_code); } /* We only handle these cases in make_failmsg, so convert any * (future?) unknown one. */ if (failure_code != WIRE_INVALID_ONION_VERSION && failure_code != WIRE_INVALID_ONION_HMAC && failure_code != WIRE_INVALID_ONION_KEY) { status_unusual("Unknown update_fail_malformed_htlc code %u:" " sending temporary_channel_failure", failure_code); failure_code = WIRE_TEMPORARY_CHANNEL_FAILURE; } e = channel_fail_htlc(peer->channel, LOCAL, id, &htlc); switch (e) { case CHANNEL_ERR_REMOVE_OK: /* FIXME: Do this! */ /* BOLT #2: * * - if the `sha256_of_onion` in `update_fail_malformed_htlc` * doesn't match the onion it sent: * - MAY retry or choose an alternate error response. */ /* This is the only case where we set failcode for a non-local * failure; in a way, it is, since we have to report it. */ htlc->failcode = failure_code; start_commit_timer(peer); return; case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, &peer->channel_id, "Bad update_fail_malformed_htlc: failed to remove %" PRIu64 " error %s", id, channel_remove_err_name(e)); } abort(); } static void handle_peer_shutdown(struct peer *peer, const u8 *shutdown) { struct channel_id channel_id; u8 *scriptpubkey; /* Disable the channel. */ send_channel_update(peer, ROUTING_FLAGS_DISABLED); if (!fromwire_shutdown(tmpctx, shutdown, &channel_id, &scriptpubkey)) peer_failed(&peer->cs, &peer->channel_id, "Bad shutdown %s", tal_hex(peer, shutdown)); /* Tell master: we don't have to wait because on reconnect other end * will re-send anyway. */ wire_sync_write(MASTER_FD, take(towire_channel_got_shutdown(NULL, scriptpubkey))); peer->shutdown_sent[REMOTE] = true; /* BOLT #2: * * A receiving node: * ... * - once there are no outstanding updates on the peer, UNLESS * it has already sent a `shutdown`: * - MUST reply to a `shutdown` message with a `shutdown` */ if (!peer->shutdown_sent[LOCAL]) { peer->send_shutdown = true; start_commit_timer(peer); } billboard_update(peer); } static void peer_in(struct peer *peer, const u8 *msg) { enum wire_type type = fromwire_peektype(msg); peer->last_recv = time_now(); /* Catch our own ping replies. */ if (type == WIRE_PONG && peer->expecting_pong) { peer->expecting_pong = false; return; } if (handle_peer_gossip_or_error(PEER_FD, GOSSIP_FD, &peer->cs, &peer->channel_id, msg)) return; /* Must get funding_locked before almost anything. */ if (!peer->funding_locked[REMOTE]) { if (type != WIRE_FUNDING_LOCKED && type != WIRE_PONG && type != WIRE_SHUTDOWN /* lnd sends these early; it's harmless. */ && type != WIRE_UPDATE_FEE && type != WIRE_ANNOUNCEMENT_SIGNATURES) { peer_failed(&peer->cs, &peer->channel_id, "%s (%u) before funding locked", wire_type_name(type), type); } } switch (type) { case WIRE_FUNDING_LOCKED: handle_peer_funding_locked(peer, msg); return; case WIRE_ANNOUNCEMENT_SIGNATURES: handle_peer_announcement_signatures(peer, msg); return; case WIRE_UPDATE_ADD_HTLC: handle_peer_add_htlc(peer, msg); return; case WIRE_COMMITMENT_SIGNED: handle_peer_commit_sig(peer, msg); return; case WIRE_UPDATE_FEE: handle_peer_feechange(peer, msg); return; case WIRE_REVOKE_AND_ACK: handle_peer_revoke_and_ack(peer, msg); return; case WIRE_UPDATE_FULFILL_HTLC: handle_peer_fulfill_htlc(peer, msg); return; case WIRE_UPDATE_FAIL_HTLC: handle_peer_fail_htlc(peer, msg); return; case WIRE_UPDATE_FAIL_MALFORMED_HTLC: handle_peer_fail_malformed_htlc(peer, msg); return; case WIRE_SHUTDOWN: handle_peer_shutdown(peer, msg); return; case WIRE_INIT: case WIRE_OPEN_CHANNEL: case WIRE_ACCEPT_CHANNEL: case WIRE_FUNDING_CREATED: case WIRE_FUNDING_SIGNED: case WIRE_CHANNEL_REESTABLISH: case WIRE_CLOSING_SIGNED: break; /* These are all swallowed by handle_peer_gossip_or_error */ case WIRE_CHANNEL_ANNOUNCEMENT: case WIRE_CHANNEL_UPDATE: case WIRE_NODE_ANNOUNCEMENT: case WIRE_QUERY_SHORT_CHANNEL_IDS: case WIRE_QUERY_CHANNEL_RANGE: case WIRE_REPLY_CHANNEL_RANGE: case WIRE_GOSSIP_TIMESTAMP_FILTER: case WIRE_REPLY_SHORT_CHANNEL_IDS_END: case WIRE_PING: case WIRE_PONG: case WIRE_ERROR: abort(); } peer_failed(&peer->cs, &peer->channel_id, "Peer sent unknown message %u (%s)", type, wire_type_name(type)); } static void resend_revoke(struct peer *peer) { struct pubkey point; /* Current commit is peer->next_index[LOCAL]-1, revoke prior */ u8 *msg = make_revocation_msg(peer, peer->next_index[LOCAL]-2, &point); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } static void send_fail_or_fulfill(struct peer *peer, const struct htlc *h) { u8 *msg; /* Note that if h->shared_secret is NULL, it means that we knew * this HTLC was invalid, but we still needed to hand it to lightningd * for the db, etc. So in that case, we use our own saved failcode. * * This also lets us distinguish between "we can't decode onion" and * "next hop said it can't decode onion". That second case is the * only case where we use a failcode for a non-local error. */ /* Malformed: use special reply since we can't onion. */ if (!h->shared_secret) { struct sha256 sha256_of_onion; sha256(&sha256_of_onion, h->routing, tal_count(h->routing)); msg = towire_update_fail_malformed_htlc(NULL, &peer->channel_id, h->id, &sha256_of_onion, h->why_bad_onion); } else if (h->failcode || h->fail) { const u8 *onion; if (h->failcode) { /* Local failure, make a message. */ u8 *failmsg = make_failmsg(tmpctx, peer, h, h->failcode, h->failed_scid, &h->next_onion_sha); onion = create_onionreply(tmpctx, h->shared_secret, failmsg); } else /* Remote failure, just forward. */ onion = h->fail; /* Now we wrap, just before sending out. */ msg = towire_update_fail_htlc(peer, &peer->channel_id, h->id, wrap_onionreply(tmpctx, h->shared_secret, onion)); } else if (h->r) { msg = towire_update_fulfill_htlc(NULL, &peer->channel_id, h->id, h->r); } else peer_failed(&peer->cs, &peer->channel_id, "HTLC %"PRIu64" state %s not failed/fulfilled", h->id, htlc_state_name(h->state)); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } static void resend_commitment(struct peer *peer, const struct changed_htlc *last) { size_t i; struct bitcoin_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; u8 *msg; status_trace("Retransmitting commitment, feerate LOCAL=%u REMOTE=%u", channel_feerate(peer->channel, LOCAL), channel_feerate(peer->channel, REMOTE)); /* BOLT #2: * * - if `next_local_commitment_number` is equal to the commitment * number of the last `commitment_signed` message the receiving node * has sent: * - MUST reuse the same commitment number for its next * `commitment_signed`. */ /* In our case, we consider ourselves already committed to this, so * retransmission is simplest. */ for (i = 0; i < tal_count(last); i++) { const struct htlc *h; h = channel_get_htlc(peer->channel, htlc_state_owner(last[i].newstate), last[i].id); /* I think this can happen if we actually received revoke_and_ack * then they asked for a retransmit */ if (!h) peer_failed(&peer->cs, &peer->channel_id, "Can't find HTLC %"PRIu64" to resend", last[i].id); if (h->state == SENT_ADD_COMMIT) { u8 *msg = towire_update_add_htlc(NULL, &peer->channel_id, h->id, h->amount, &h->rhash, abs_locktime_to_blocks( &h->expiry), h->routing); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } else if (h->state == SENT_REMOVE_COMMIT) { send_fail_or_fulfill(peer, h); } } /* Make sure they have the correct fee. */ if (peer->channel->funder == LOCAL) { msg = towire_update_fee(NULL, &peer->channel_id, channel_feerate(peer->channel, REMOTE)); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } /* Re-send the commitment_signed itself. */ htlc_sigs = calc_commitsigs(tmpctx, peer, peer->next_index[REMOTE]-1, &commit_sig); msg = towire_commitment_signed(NULL, &peer->channel_id, &commit_sig.s, htlc_sigs); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); /* If we have already received the revocation for the previous, the * other side shouldn't be asking for a retransmit! */ if (peer->revocations_received != peer->next_index[REMOTE] - 2) status_unusual("Retransmitted commitment_signed %"PRIu64 " but they already send revocation %"PRIu64"?", peer->next_index[REMOTE]-1, peer->revocations_received); } /* BOLT #2: * * A receiving node: * - if it supports `option_data_loss_protect`, AND the * `option_data_loss_protect` fields are present: * - if `next_remote_revocation_number` is greater than expected above, * AND `your_last_per_commitment_secret` is correct for that * `next_remote_revocation_number` minus 1: */ static void check_future_dataloss_fields(struct peer *peer, u64 next_remote_revocation_number, const struct secret *last_local_per_commit_secret, const struct pubkey *remote_current_per_commitment_point) { const u8 *msg; bool correct; assert(next_remote_revocation_number > peer->next_index[LOCAL] - 1); msg = towire_hsm_check_future_secret(NULL, next_remote_revocation_number - 1, last_local_per_commit_secret); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsm_check_future_secret_reply(msg, &correct)) status_failed(STATUS_FAIL_HSM_IO, "Bad hsm_check_future_secret_reply: %s", tal_hex(tmpctx, msg)); if (!correct) peer_failed(&peer->cs, &peer->channel_id, "bad future last_local_per_commit_secret: %"PRIu64 " vs %"PRIu64, next_remote_revocation_number, peer->next_index[LOCAL] - 1); /* Oh shit, they really are from the future! */ peer_billboard(true, "They have future commitment number %"PRIu64 " vs our %"PRIu64". We must wait for them to close!", next_remote_revocation_number, peer->next_index[LOCAL] - 1); /* BOLT #2: * - MUST NOT broadcast its commitment transaction. * - SHOULD fail the channel. * - SHOULD store `my_current_per_commitment_point` to * retrieve funds should the sending node broadcast its * commitment transaction on-chain. */ wire_sync_write(MASTER_FD, take(towire_channel_fail_fallen_behind(NULL, remote_current_per_commitment_point))); /* We have to send them an error to trigger dropping to chain. */ peer_failed(&peer->cs, &peer->channel_id, "Awaiting unilateral close"); } /* BOLT #2: * * A receiving node: * - if it supports `option_data_loss_protect`, AND the * `option_data_loss_protect` fields are present: *... * - otherwise (`your_last_per_commitment_secret` or * `my_current_per_commitment_point` do not match the expected values): * - SHOULD fail the channel. */ static void check_current_dataloss_fields(struct peer *peer, u64 next_remote_revocation_number, u64 next_local_commitment_number, const struct secret *last_local_per_commit_secret, const struct pubkey *remote_current_per_commitment_point) { struct secret old_commit_secret; /* By the time we're called, we've ensured this is a valid revocation * number. */ assert(next_remote_revocation_number == peer->next_index[LOCAL] - 2 || next_remote_revocation_number == peer->next_index[LOCAL] - 1); /* By the time we're called, we've ensured we're within 1 of * their commitment chain */ assert(next_local_commitment_number == peer->next_index[REMOTE] || next_local_commitment_number == peer->next_index[REMOTE] - 1); if (!last_local_per_commit_secret) return; /* BOLT #2: * - if `next_remote_revocation_number` equals 0: * - MUST set `your_last_per_commitment_secret` to all zeroes */ status_trace("next_remote_revocation_number = %"PRIu64, next_remote_revocation_number); if (next_remote_revocation_number == 0) memset(&old_commit_secret, 0, sizeof(old_commit_secret)); else { struct pubkey unused; /* This gets previous revocation number, since asking for * commitment point N gives secret for N-2 */ get_per_commitment_point(next_remote_revocation_number+1, &unused, &old_commit_secret); } if (!secret_eq_consttime(&old_commit_secret, last_local_per_commit_secret)) peer_failed(&peer->cs, &peer->channel_id, "bad reestablish: your_last_per_commitment_secret %"PRIu64 ": %s should be %s", next_remote_revocation_number, type_to_string(tmpctx, struct secret, last_local_per_commit_secret), type_to_string(tmpctx, struct secret, &old_commit_secret)); status_trace("Reestablish, comparing commitments. Remote's next local commitment number" " is %"PRIu64". Our next remote is %"PRIu64" with %"PRIu64 " revocations received", next_local_commitment_number, peer->next_index[REMOTE], peer->revocations_received); /* Either they haven't received our commitment yet, or we're up to date */ if (next_local_commitment_number == peer->revocations_received + 1) { if (!pubkey_eq(remote_current_per_commitment_point, &peer->old_remote_per_commit)) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish: remote's " "my_current_per_commitment_point %"PRIu64 "is %s; expected %s (new is %s).", next_local_commitment_number - 1, type_to_string(tmpctx, struct pubkey, remote_current_per_commitment_point), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit)); } } else { /* We've sent a commit sig but haven't gotten a revoke+ack back */ if (!pubkey_eq(remote_current_per_commitment_point, &peer->remote_per_commit)) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish: remote's " "my_current_per_commitment_point %"PRIu64 "is %s; expected %s (old is %s).", next_local_commitment_number - 1, type_to_string(tmpctx, struct pubkey, remote_current_per_commitment_point), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit)); } } status_trace("option_data_loss_protect: fields are correct"); } static void peer_reconnect(struct peer *peer, const struct secret *last_remote_per_commit_secret) { struct channel_id channel_id; /* Note: BOLT #2 uses these names, which are sender-relative! */ u64 next_local_commitment_number, next_remote_revocation_number; bool retransmit_revoke_and_ack, retransmit_commitment_signed; struct htlc_map_iter it; const struct htlc *htlc; u8 *msg; struct pubkey my_current_per_commitment_point, remote_current_per_commitment_point; struct secret last_local_per_commitment_secret; bool dataloss_protect; const u8 *premature_funding_locked = NULL; dataloss_protect = local_feature_negotiated(peer->localfeatures, LOCAL_DATA_LOSS_PROTECT); /* Our current per-commitment point is the commitment point in the last * received signed commitment */ get_per_commitment_point(peer->next_index[LOCAL] - 1, &my_current_per_commitment_point, NULL); /* BOLT #2: * * - upon reconnection: * - if a channel is in an error state: * - SHOULD retransmit the error packet and ignore any other packets for * that channel. * - otherwise: * - MUST transmit `channel_reestablish` for each channel. * - MUST wait to receive the other node's `channel_reestablish` * message before sending any other messages for that channel. * * The sending node: * - MUST set `next_local_commitment_number` to the commitment number * of the next `commitment_signed` it expects to receive. * - MUST set `next_remote_revocation_number` to the commitment number * of the next `revoke_and_ack` message it expects to receive. * - if it supports `option_data_loss_protect`: * - if `next_remote_revocation_number` equals 0: * - MUST set `your_last_per_commitment_secret` to all zeroes * - otherwise: * - MUST set `your_last_per_commitment_secret` to the last * `per_commitment_secret` it received */ if (dataloss_protect) { msg = towire_channel_reestablish_option_data_loss_protect (NULL, &peer->channel_id, peer->next_index[LOCAL], peer->revocations_received, last_remote_per_commit_secret, &my_current_per_commitment_point); } else { msg = towire_channel_reestablish (NULL, &peer->channel_id, peer->next_index[LOCAL], peer->revocations_received); } sync_crypto_write(&peer->cs, PEER_FD, take(msg)); peer_billboard(false, "Sent reestablish, waiting for theirs"); /* Read until they say something interesting (don't forward * gossip *to* them yet: we might try sending channel_update * before we've reestablished channel). */ do { clean_tmpctx(); msg = sync_crypto_read(tmpctx, &peer->cs, PEER_FD); /* Older LND sometimes sends funding_locked before reestablish! */ if (fromwire_peektype(msg) == WIRE_FUNDING_LOCKED && !premature_funding_locked) { status_trace("Stashing early funding_locked msg!"); premature_funding_locked = tal_steal(peer, msg); msg = NULL; } } while (!msg || handle_peer_gossip_or_error(PEER_FD, GOSSIP_FD, &peer->cs, &peer->channel_id, msg)); if (dataloss_protect) { if (!fromwire_channel_reestablish_option_data_loss_protect(msg, &channel_id, &next_local_commitment_number, &next_remote_revocation_number, &last_local_per_commitment_secret, &remote_current_per_commitment_point)) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish dataloss msg: %s %s", wire_type_name(fromwire_peektype(msg)), tal_hex(msg, msg)); } } else { if (!fromwire_channel_reestablish(msg, &channel_id, &next_local_commitment_number, &next_remote_revocation_number)) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish msg: %s %s", wire_type_name(fromwire_peektype(msg)), tal_hex(msg, msg)); } } status_trace("Got reestablish commit=%"PRIu64" revoke=%"PRIu64, next_local_commitment_number, next_remote_revocation_number); /* BOLT #2: * * - if `next_local_commitment_number` is 1 in both the * `channel_reestablish` it sent and received: * - MUST retransmit `funding_locked`. * - otherwise: * - MUST NOT retransmit `funding_locked`. */ if (peer->funding_locked[LOCAL] && peer->next_index[LOCAL] == 1 && next_local_commitment_number == 1) { u8 *msg; /* Contains per commit point #1, for first post-opening commit */ msg = towire_funding_locked(NULL, &peer->channel_id, &peer->next_local_per_commit); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); } /* Note: next_index is the index of the current commit we're working * on, but BOLT #2 refers to the *last* commit index, so we -1 where * required. */ /* BOLT #2: * * - if `next_remote_revocation_number` is equal to the commitment * number of the last `revoke_and_ack` the receiving node sent, AND * the receiving node hasn't already received a `closing_signed`: * - MUST re-send the `revoke_and_ack`. * - otherwise: * - if `next_remote_revocation_number` is not equal to 1 greater * than the commitment number of the last `revoke_and_ack` the * receiving node has sent: * - SHOULD fail the channel. * - if it has not sent `revoke_and_ack`, AND * `next_remote_revocation_number` is equal to 0: * - SHOULD fail the channel. */ if (next_remote_revocation_number == peer->next_index[LOCAL] - 2) { /* Don't try to retransmit revocation index -1! */ if (peer->next_index[LOCAL] < 2) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish revocation_number: %" PRIu64, next_remote_revocation_number); } retransmit_revoke_and_ack = true; } else if (next_remote_revocation_number < peer->next_index[LOCAL] - 1) { peer_failed(&peer->cs, &peer->channel_id, "bad reestablish revocation_number: %"PRIu64 " vs %"PRIu64, next_remote_revocation_number, peer->next_index[LOCAL]); } else if (next_remote_revocation_number > peer->next_index[LOCAL] - 1) { if (!dataloss_protect) /* They don't support option_data_loss_protect, we * fail it due to unexpected number */ peer_failed(&peer->cs, &peer->channel_id, "bad reestablish revocation_number: %"PRIu64 " vs %"PRIu64, next_remote_revocation_number, peer->next_index[LOCAL] - 1); /* Remote claims it's ahead of us: can it prove it? * Does not return. */ check_future_dataloss_fields(peer, next_remote_revocation_number, &last_local_per_commitment_secret, &remote_current_per_commitment_point); } else retransmit_revoke_and_ack = false; /* BOLT #2: * * - if `next_local_commitment_number` is equal to the commitment * number of the last `commitment_signed` message the receiving node * has sent: * - MUST reuse the same commitment number for its next * `commitment_signed`. */ if (next_local_commitment_number == peer->next_index[REMOTE] - 1) { /* We completed opening, we don't re-transmit that one! */ if (next_local_commitment_number == 0) peer_failed(&peer->cs, &peer->channel_id, "bad reestablish commitment_number: %" PRIu64, next_local_commitment_number); retransmit_commitment_signed = true; /* BOLT #2: * * - otherwise: * - if `next_local_commitment_number` is not 1 greater than the * commitment number of the last `commitment_signed` message the * receiving node has sent: * - SHOULD fail the channel. */ } else if (next_local_commitment_number != peer->next_index[REMOTE]) peer_failed(&peer->cs, &peer->channel_id, "bad reestablish commitment_number: %"PRIu64 " vs %"PRIu64, next_local_commitment_number, peer->next_index[REMOTE]); else retransmit_commitment_signed = false; /* After we checked basic sanity, we check dataloss fields if any */ if (dataloss_protect) check_current_dataloss_fields(peer, next_remote_revocation_number, next_local_commitment_number, &last_local_per_commitment_secret, &remote_current_per_commitment_point); /* We have to re-send in the same order we sent originally: * revoke_and_ack (usually) alters our next commitment. */ if (retransmit_revoke_and_ack && !peer->last_was_revoke) resend_revoke(peer); if (retransmit_commitment_signed) resend_commitment(peer, peer->last_sent_commit); /* This covers the case where we sent revoke after commit. */ if (retransmit_revoke_and_ack && peer->last_was_revoke) resend_revoke(peer); /* BOLT #2: * * - upon reconnection: * - if it has sent a previous `shutdown`: * - MUST retransmit `shutdown`. */ /* (If we had sent `closing_signed`, we'd be in closingd). */ maybe_send_shutdown(peer); /* Corner case: we didn't send shutdown before because update_add_htlc * pending, but now they're cleared by restart, and we're actually * complete. In that case, their `shutdown` will trigger us. */ /* Start commit timer: if we sent revoke we might need it. */ start_commit_timer(peer); /* Now, re-send any that we're supposed to be failing. */ for (htlc = htlc_map_first(peer->channel->htlcs, &it); htlc; htlc = htlc_map_next(peer->channel->htlcs, &it)) { if (htlc->state == SENT_REMOVE_HTLC) send_fail_or_fulfill(peer, htlc); } /* Corner case: we will get upset with them if they send * commitment_signed with no changes. But it could be that we sent a * feechange, they acked, and now they want to commit it; we can't * even tell by seeing if fees are different (short of saving full fee * state in database) since it could be a tiny feechange, or two * feechanges which cancelled out. */ if (peer->channel->funder == LOCAL) peer->channel->changes_pending[LOCAL] = true; peer_billboard(true, "Reconnected, and reestablished."); if (premature_funding_locked) { handle_peer_funding_locked(peer, premature_funding_locked); tal_free(premature_funding_locked); } } /* Funding has locked in, and reached depth. */ static void handle_funding_locked(struct peer *peer, const u8 *msg) { unsigned int depth; if (!fromwire_channel_funding_locked(msg, &peer->short_channel_ids[LOCAL], &depth)) master_badmsg(WIRE_CHANNEL_FUNDING_LOCKED, msg); /* Too late, we're shutting down! */ if (peer->shutdown_sent[LOCAL]) return; if (!peer->funding_locked[LOCAL]) { status_trace("funding_locked: sending commit index %"PRIu64": %s", peer->next_index[LOCAL], type_to_string(tmpctx, struct pubkey, &peer->next_local_per_commit)); msg = towire_funding_locked(NULL, &peer->channel_id, &peer->next_local_per_commit); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); peer->funding_locked[LOCAL] = true; } peer->announce_depth_reached = (depth >= ANNOUNCE_MIN_DEPTH); /* Send temporary or final announcements */ channel_announcement_negotiate(peer); billboard_update(peer); } static void handle_offer_htlc(struct peer *peer, const u8 *inmsg) { u8 *msg; u32 cltv_expiry; struct amount_msat amount; struct sha256 payment_hash; u8 onion_routing_packet[TOTAL_PACKET_SIZE]; enum channel_add_err e; enum onion_type failcode; /* Subtle: must be tal object since we marshal using tal_bytelen() */ const char *failmsg; if (!peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) status_failed(STATUS_FAIL_MASTER_IO, "funding not locked for offer_htlc"); if (!fromwire_channel_offer_htlc(inmsg, &amount, &cltv_expiry, &payment_hash, onion_routing_packet)) master_badmsg(WIRE_CHANNEL_OFFER_HTLC, inmsg); e = channel_add_htlc(peer->channel, LOCAL, peer->htlc_id, amount, cltv_expiry, &payment_hash, onion_routing_packet, NULL); status_trace("Adding HTLC %"PRIu64" amount=%s cltv=%u gave %s", peer->htlc_id, type_to_string(tmpctx, struct amount_msat, &amount), cltv_expiry, channel_add_err_name(e)); switch (e) { case CHANNEL_ERR_ADD_OK: /* Tell the peer. */ msg = towire_update_add_htlc(NULL, &peer->channel_id, peer->htlc_id, amount, &payment_hash, cltv_expiry, onion_routing_packet); sync_crypto_write(&peer->cs, PEER_FD, take(msg)); start_commit_timer(peer); /* Tell the master. */ msg = towire_channel_offer_htlc_reply(NULL, peer->htlc_id, 0, NULL); wire_sync_write(MASTER_FD, take(msg)); peer->htlc_id++; return; case CHANNEL_ERR_INVALID_EXPIRY: failcode = WIRE_INCORRECT_CLTV_EXPIRY; failmsg = tal_fmt(inmsg, "Invalid cltv_expiry %u", cltv_expiry); goto failed; case CHANNEL_ERR_DUPLICATE: case CHANNEL_ERR_DUPLICATE_ID_DIFFERENT: status_failed(STATUS_FAIL_MASTER_IO, "Duplicate HTLC %"PRIu64, peer->htlc_id); /* FIXME: Fuzz the boundaries a bit to avoid probing? */ case CHANNEL_ERR_MAX_HTLC_VALUE_EXCEEDED: failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Maximum value exceeded"); goto failed; case CHANNEL_ERR_CHANNEL_CAPACITY_EXCEEDED: failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Capacity exceeded"); goto failed; case CHANNEL_ERR_HTLC_BELOW_MINIMUM: failcode = WIRE_AMOUNT_BELOW_MINIMUM; failmsg = tal_fmt(inmsg, "HTLC too small (%s minimum)", type_to_string(tmpctx, struct amount_msat, &peer->channel->config[REMOTE].htlc_minimum)); goto failed; case CHANNEL_ERR_TOO_MANY_HTLCS: failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Too many HTLCs"); goto failed; } /* Shouldn't return anything else! */ abort(); failed: msg = towire_channel_offer_htlc_reply(NULL, 0, failcode, (u8*)failmsg); wire_sync_write(MASTER_FD, take(msg)); } static void handle_feerates(struct peer *peer, const u8 *inmsg) { u32 feerate; if (!fromwire_channel_feerates(inmsg, &feerate, &peer->feerate_min, &peer->feerate_max)) master_badmsg(WIRE_CHANNEL_FEERATES, inmsg); /* BOLT #2: * * The node _responsible_ for paying the Bitcoin fee: * - SHOULD send `update_fee` to ensure the current fee rate is * sufficient (by a significant margin) for timely processing of the * commitment transaction. */ if (peer->channel->funder == LOCAL) { peer->desired_feerate = feerate; start_commit_timer(peer); } else { /* BOLT #2: * * The node _not responsible_ for paying the Bitcoin fee: * - MUST NOT send `update_fee`. */ /* FIXME: We could drop to chain if fees are too low, but * that's fraught too. */ } } static void handle_preimage(struct peer *peer, const u8 *inmsg) { struct fulfilled_htlc fulfilled_htlc; struct htlc *h; if (!fromwire_channel_fulfill_htlc(inmsg, &fulfilled_htlc)) master_badmsg(WIRE_CHANNEL_FULFILL_HTLC, inmsg); switch (channel_fulfill_htlc(peer->channel, REMOTE, fulfilled_htlc.id, &fulfilled_htlc.payment_preimage, &h)) { case CHANNEL_ERR_REMOVE_OK: send_fail_or_fulfill(peer, h); start_commit_timer(peer); return; /* These shouldn't happen, because any offered HTLC (which would give * us the preimage) should have timed out long before. If we * were to get preimages from other sources, this could happen. */ case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: status_failed(STATUS_FAIL_MASTER_IO, "HTLC %"PRIu64" preimage failed", fulfilled_htlc.id); } abort(); } static void handle_fail(struct peer *peer, const u8 *inmsg) { struct failed_htlc *failed_htlc; enum channel_remove_err e; struct htlc *h; if (!fromwire_channel_fail_htlc(inmsg, inmsg, &failed_htlc)) master_badmsg(WIRE_CHANNEL_FAIL_HTLC, inmsg); e = channel_fail_htlc(peer->channel, REMOTE, failed_htlc->id, &h); switch (e) { case CHANNEL_ERR_REMOVE_OK: h->failcode = failed_htlc->failcode; h->fail = tal_steal(h, failed_htlc->failreason); h->failed_scid = tal_steal(h, failed_htlc->scid); send_fail_or_fulfill(peer, h); start_commit_timer(peer); return; case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: status_failed(STATUS_FAIL_MASTER_IO, "HTLC %"PRIu64" removal failed: %s", failed_htlc->id, channel_remove_err_name(e)); } abort(); } static void handle_shutdown_cmd(struct peer *peer, const u8 *inmsg) { if (!fromwire_channel_send_shutdown(inmsg)) master_badmsg(WIRE_CHANNEL_SEND_SHUTDOWN, inmsg); /* We can't send this until commit (if any) is done, so start timer. */ peer->send_shutdown = true; start_commit_timer(peer); } #if DEVELOPER static void handle_dev_reenable_commit(struct peer *peer) { dev_suppress_commit = false; start_commit_timer(peer); status_trace("dev_reenable_commit"); wire_sync_write(MASTER_FD, take(towire_channel_dev_reenable_commit_reply(NULL))); } static void handle_dev_memleak(struct peer *peer, const u8 *msg) { struct htable *memtable; bool found_leak; memtable = memleak_enter_allocations(tmpctx, msg, msg); /* Now delete peer and things it has pointers to. */ memleak_remove_referenced(memtable, peer); memleak_remove_htable(memtable, &peer->channel->htlcs->raw); found_leak = dump_memleak(memtable); wire_sync_write(MASTER_FD, take(towire_channel_dev_memleak_reply(NULL, found_leak))); } #endif /* DEVELOPER */ static void req_in(struct peer *peer, const u8 *msg) { enum channel_wire_type t = fromwire_peektype(msg); switch (t) { case WIRE_CHANNEL_FUNDING_LOCKED: handle_funding_locked(peer, msg); return; case WIRE_CHANNEL_OFFER_HTLC: handle_offer_htlc(peer, msg); return; case WIRE_CHANNEL_FEERATES: handle_feerates(peer, msg); return; case WIRE_CHANNEL_FULFILL_HTLC: handle_preimage(peer, msg); return; case WIRE_CHANNEL_FAIL_HTLC: handle_fail(peer, msg); return; case WIRE_CHANNEL_SEND_SHUTDOWN: handle_shutdown_cmd(peer, msg); return; #if DEVELOPER case WIRE_CHANNEL_DEV_REENABLE_COMMIT: handle_dev_reenable_commit(peer); return; case WIRE_CHANNEL_DEV_MEMLEAK: handle_dev_memleak(peer, msg); return; #else case WIRE_CHANNEL_DEV_REENABLE_COMMIT: case WIRE_CHANNEL_DEV_MEMLEAK: #endif /* DEVELOPER */ case WIRE_CHANNEL_INIT: case WIRE_CHANNEL_OFFER_HTLC_REPLY: case WIRE_CHANNEL_SENDING_COMMITSIG: case WIRE_CHANNEL_GOT_COMMITSIG: case WIRE_CHANNEL_GOT_REVOKE: case WIRE_CHANNEL_SENDING_COMMITSIG_REPLY: case WIRE_CHANNEL_GOT_COMMITSIG_REPLY: case WIRE_CHANNEL_GOT_REVOKE_REPLY: case WIRE_CHANNEL_GOT_FUNDING_LOCKED: case WIRE_CHANNEL_GOT_SHUTDOWN: case WIRE_CHANNEL_SHUTDOWN_COMPLETE: case WIRE_CHANNEL_DEV_REENABLE_COMMIT_REPLY: case WIRE_CHANNEL_FAIL_FALLEN_BEHIND: case WIRE_CHANNEL_DEV_MEMLEAK_REPLY: break; } master_badmsg(-1, msg); } static void init_shared_secrets(struct channel *channel, const struct added_htlc *htlcs, const enum htlc_state *hstates) { for (size_t i = 0; i < tal_count(htlcs); i++) { struct htlc *htlc; /* We only derive this for HTLCs *they* added. */ if (htlc_state_owner(hstates[i]) != REMOTE) continue; htlc = channel_get_htlc(channel, REMOTE, htlcs[i].id); htlc->shared_secret = get_shared_secret(htlc, htlc, &htlc->why_bad_onion, &htlc->next_onion_sha); } } /* We do this synchronously. */ static void init_channel(struct peer *peer) { struct basepoints points[NUM_SIDES]; struct amount_sat funding; u16 funding_txout; struct amount_msat local_msat; struct pubkey funding_pubkey[NUM_SIDES]; struct channel_config conf[NUM_SIDES]; struct bitcoin_txid funding_txid; enum side funder; enum htlc_state *hstates; struct fulfilled_htlc *fulfilled; enum side *fulfilled_sides; struct failed_htlc **failed; enum side *failed_sides; struct added_htlc *htlcs; bool reconnected; u8 *funding_signed; const u8 *msg; u32 feerate_per_kw[NUM_SIDES]; struct secret last_remote_per_commit_secret; assert(!(fcntl(MASTER_FD, F_GETFL) & O_NONBLOCK)); status_setup_sync(MASTER_FD); msg = wire_sync_read(tmpctx, MASTER_FD); if (!fromwire_channel_init(peer, msg, &peer->chain_hash, &funding_txid, &funding_txout, &funding, &conf[LOCAL], &conf[REMOTE], feerate_per_kw, &peer->feerate_min, &peer->feerate_max, &peer->their_commit_sig, &peer->cs, &funding_pubkey[REMOTE], &points[REMOTE], &peer->remote_per_commit, &peer->old_remote_per_commit, &funder, &peer->fee_base, &peer->fee_per_satoshi, &local_msat, &points[LOCAL], &funding_pubkey[LOCAL], &peer->node_ids[LOCAL], &peer->node_ids[REMOTE], &peer->commit_msec, &peer->cltv_delta, &peer->last_was_revoke, &peer->last_sent_commit, &peer->next_index[LOCAL], &peer->next_index[REMOTE], &peer->revocations_received, &peer->htlc_id, &htlcs, &hstates, &fulfilled, &fulfilled_sides, &failed, &failed_sides, &peer->funding_locked[LOCAL], &peer->funding_locked[REMOTE], &peer->short_channel_ids[LOCAL], &reconnected, &peer->send_shutdown, &peer->shutdown_sent[REMOTE], &peer->final_scriptpubkey, &peer->channel_flags, &funding_signed, &peer->announce_depth_reached, &last_remote_per_commit_secret, &peer->localfeatures)) master_badmsg(WIRE_CHANNEL_INIT, msg); status_trace("init %s: remote_per_commit = %s, old_remote_per_commit = %s" " next_idx_local = %"PRIu64 " next_idx_remote = %"PRIu64 " revocations_received = %"PRIu64 " feerates %u/%u (range %u-%u)", side_to_str(funder), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit), peer->next_index[LOCAL], peer->next_index[REMOTE], peer->revocations_received, feerate_per_kw[LOCAL], feerate_per_kw[REMOTE], peer->feerate_min, peer->feerate_max); /* First commit is used for opening: if we've sent 0, we're on * index 1. */ assert(peer->next_index[LOCAL] > 0); assert(peer->next_index[REMOTE] > 0); get_per_commitment_point(peer->next_index[LOCAL], &peer->next_local_per_commit, NULL); /* channel_id is set from funding txout */ derive_channel_id(&peer->channel_id, &funding_txid, funding_txout); peer->channel = new_full_channel(peer, &peer->chain_hash, &funding_txid, funding_txout, funding, local_msat, feerate_per_kw, &conf[LOCAL], &conf[REMOTE], &points[LOCAL], &points[REMOTE], &funding_pubkey[LOCAL], &funding_pubkey[REMOTE], funder); if (!channel_force_htlcs(peer->channel, htlcs, hstates, fulfilled, fulfilled_sides, cast_const2(const struct failed_htlc **, failed), failed_sides)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not restore HTLCs"); /* We derive shared secrets for each remote HTLC, so we can * create error packet if necessary. */ init_shared_secrets(peer->channel, htlcs, hstates); /* We don't need these any more, so free them. */ tal_free(htlcs); tal_free(hstates); tal_free(fulfilled); tal_free(fulfilled_sides); tal_free(failed); tal_free(failed_sides); peer->channel_direction = get_channel_direction( &peer->node_ids[LOCAL], &peer->node_ids[REMOTE]); /* Default desired feerate is the feerate we set for them last. */ if (peer->channel->funder == LOCAL) peer->desired_feerate = feerate_per_kw[REMOTE]; /* OK, now we can process peer messages. */ if (reconnected) peer_reconnect(peer, &last_remote_per_commit_secret); /* If we have a funding_signed message, send that immediately */ if (funding_signed) sync_crypto_write(&peer->cs, PEER_FD, take(funding_signed)); /* Reenable channel */ channel_announcement_negotiate(peer); billboard_update(peer); } static void send_shutdown_complete(struct peer *peer) { /* Now we can tell master shutdown is complete. */ wire_sync_write(MASTER_FD, take(towire_channel_shutdown_complete(NULL, &peer->cs))); fdpass_send(MASTER_FD, PEER_FD); fdpass_send(MASTER_FD, GOSSIP_FD); close(MASTER_FD); } int main(int argc, char *argv[]) { setup_locale(); int i, nfds; fd_set fds_in, fds_out; struct peer *peer; subdaemon_setup(argc, argv); peer = tal(NULL, struct peer); peer->expecting_pong = false; timers_init(&peer->timers, time_mono()); peer->commit_timer = NULL; peer->have_sigs[LOCAL] = peer->have_sigs[REMOTE] = false; peer->announce_depth_reached = false; peer->channel_local_active = false; peer->from_master = msg_queue_new(peer); peer->from_gossipd = msg_queue_new(peer); peer->shutdown_sent[LOCAL] = false; peer->last_update_timestamp = 0; /* We actually received it in the previous daemon, but near enough */ peer->last_recv = time_now(); /* We send these to HSM to get real signatures; don't have valgrind * complain. */ for (i = 0; i < NUM_SIDES; i++) { memset(&peer->announcement_node_sigs[i], 0, sizeof(peer->announcement_node_sigs[i])); memset(&peer->announcement_bitcoin_sigs[i], 0, sizeof(peer->announcement_bitcoin_sigs[i])); } /* Read init_channel message sync. */ init_channel(peer); FD_ZERO(&fds_in); FD_SET(MASTER_FD, &fds_in); FD_SET(PEER_FD, &fds_in); FD_SET(GOSSIP_FD, &fds_in); FD_ZERO(&fds_out); FD_SET(PEER_FD, &fds_out); nfds = GOSSIP_FD+1; while (!shutdown_complete(peer)) { struct timemono first; fd_set rfds = fds_in; struct timeval timeout, *tptr; struct timer *expired; const u8 *msg; struct timemono now = time_mono(); /* Free any temporary allocations */ clean_tmpctx(); /* For simplicity, we process one event at a time. */ msg = msg_dequeue(peer->from_master); if (msg) { status_trace("Now dealing with deferred %s", channel_wire_type_name( fromwire_peektype(msg))); req_in(peer, msg); tal_free(msg); continue; } expired = timers_expire(&peer->timers, now); if (expired) { timer_expired(peer, expired); continue; } msg = msg_dequeue(peer->from_gossipd); if (msg) { status_trace("Now dealing with deferred gossip %u", fromwire_peektype(msg)); handle_gossip_msg(PEER_FD, &peer->cs, take(msg)); continue; } if (timer_earliest(&peer->timers, &first)) { timeout = timespec_to_timeval( timemono_between(first, now).ts); tptr = &timeout; } else tptr = NULL; if (select(nfds, &rfds, NULL, NULL, tptr) < 0) { /* Signals OK, eg. SIGUSR1 */ if (errno == EINTR) continue; status_failed(STATUS_FAIL_INTERNAL_ERROR, "select failed: %s", strerror(errno)); } if (FD_ISSET(MASTER_FD, &rfds)) { msg = wire_sync_read(tmpctx, MASTER_FD); if (!msg) status_failed(STATUS_FAIL_MASTER_IO, "Can't read command: %s", strerror(errno)); req_in(peer, msg); } else if (FD_ISSET(PEER_FD, &rfds)) { /* This could take forever, but who cares? */ msg = sync_crypto_read(tmpctx, &peer->cs, PEER_FD); peer_in(peer, msg); } else if (FD_ISSET(GOSSIP_FD, &rfds)) { msg = wire_sync_read(tmpctx, GOSSIP_FD); /* Gossipd hangs up on us to kill us when a new * connection comes in. */ if (!msg) peer_failed_connection_lost(); handle_gossip_msg(PEER_FD, &peer->cs, take(msg)); } } /* We only exit when shutdown is complete. */ assert(shutdown_complete(peer)); send_shutdown_complete(peer); daemon_shutdown(); return 0; }