/* 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* stdin == requests, 3 == peer, 4 = gossip, 5 = gossip_store, 6 = HSM */ #define MASTER_FD STDIN_FILENO #define HSM_FD 6 struct peer { struct per_peer_state *pps; bool funding_locked[NUM_SIDES]; u64 next_index[NUM_SIDES]; /* Features peer supports. */ u8 *their_features; /* Features we support. */ struct feature_set *our_features; /* Tolerable amounts for feerate (only relevant for fundee). */ u32 feerate_min, feerate_max; /* Feerate to be used when creating penalty transactions. */ u32 feerate_penalty; /* 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 channel_id channel_id; struct channel *channel; /* Messages from master: we queue them since we might be * waiting for a specific reply. */ struct msg_queue *from_master; 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; /* Current blockheight */ u32 our_blockheight; /* Announcement related information */ struct node_id 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]; /* If master told us to send wrong_funding */ struct bitcoin_outpoint *shutdown_wrong_funding; #if EXPERIMENTAL_FEATURES /* Do we want quiescence? */ bool stfu; /* Which side is considered the initiator? */ enum side stfu_initiator; /* Has stfu been sent by each side? */ bool stfu_sent[NUM_SIDES]; /* Updates master asked, which we've deferred while quiescing */ struct msg_queue *update_queue; #endif /* 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; /* Additional confirmations need for local lockin. */ u32 depth_togo; /* Non-empty if they specified a fixed shutdown script */ u8 *remote_upfront_shutdown_script; /* Empty commitments. Spec violation, but a minor one. */ u64 last_empty_commitment; /* Penalty bases for this channel / peer. */ struct penalty_base **pbases; /* We allow a 'tx-sigs' message between reconnect + funding_locked */ bool tx_sigs_allowed; }; 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 *update = billboard_message(tmpctx, peer->funding_locked, peer->have_sigs, peer->shutdown_sent, peer->depth_togo, num_channel_htlcs(peer->channel)); peer_billboard(false, update); } 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", hsmd_wire_name(type), strerror(errno)); msg = wire_sync_read(ctx, HSM_FD); if (!msg) status_failed(STATUS_FAIL_HSM_IO, "Reading resp to %s: %s", hsmd_wire_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 advertize the maximum value possible, defined as the smaller * of the remote's maximum in-flight HTLC or the total channel * capacity the reserve we have to keep. * FIXME: does this need fuzz? */ static struct amount_msat advertized_htlc_max(const struct channel *channel) { struct amount_sat lower_bound; struct amount_msat lower_bound_msat; /* This shouldn't fail */ if (!amount_sat_sub(&lower_bound, channel->funding, channel->config[REMOTE].channel_reserve)) { status_failed(STATUS_FAIL_INTERNAL_ERROR, "funding %s - remote reserve %s?", type_to_string(tmpctx, struct amount_sat, &channel->funding), type_to_string(tmpctx, struct amount_sat, &channel->config[REMOTE] .channel_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)); } return lower_bound_msat; } #if EXPERIMENTAL_FEATURES static void maybe_send_stfu(struct peer *peer) { if (!peer->stfu) return; if (!peer->stfu_sent[LOCAL] && !pending_updates(peer->channel, LOCAL, false)) { u8 *msg = towire_stfu(NULL, &peer->channel_id, peer->stfu_initiator == LOCAL); sync_crypto_write(peer->pps, take(msg)); peer->stfu_sent[LOCAL] = true; } if (peer->stfu_sent[LOCAL] && peer->stfu_sent[REMOTE]) { status_unusual("STFU complete: we are quiescent"); wire_sync_write(MASTER_FD, towire_channeld_dev_quiesce_reply(tmpctx)); } } static void handle_stfu(struct peer *peer, const u8 *stfu) { struct channel_id channel_id; u8 remote_initiated; if (!fromwire_stfu(stfu, &channel_id, &remote_initiated)) peer_failed_warn(peer->pps, &peer->channel_id, "Bad stfu %s", tal_hex(peer, stfu)); if (!channel_id_eq(&channel_id, &peer->channel_id)) { peer_failed_err(peer->pps, &channel_id, "Wrong stfu channel_id: expected %s, got %s", type_to_string(tmpctx, struct channel_id, &peer->channel_id), type_to_string(tmpctx, struct channel_id, &channel_id)); } /* Sanity check */ if (pending_updates(peer->channel, REMOTE, false)) peer_failed_warn(peer->pps, &peer->channel_id, "STFU but you still have updates pending?"); if (!peer->stfu) { peer->stfu = true; if (!remote_initiated) peer_failed_warn(peer->pps, &peer->channel_id, "Unsolicited STFU but you said" " you didn't initiate?"); peer->stfu_initiator = REMOTE; } else { /* BOLT-quiescent #2: * * If both sides send `stfu` simultaneously, they will both * set `initiator` to `1`, in which case the "initiator" is * arbitrarily considered to be the channel funder (the sender * of `open_channel`). */ if (remote_initiated) peer->stfu_initiator = peer->channel->opener; } /* BOLT-quiescent #2: * The receiver of `stfu`: * - if it has sent `stfu` then: * - MUST now consider the channel to be quiescent * - otherwise: * - SHOULD NOT send any more update messages. * - MUST reply with `stfu` once it can do so. */ peer->stfu_sent[REMOTE] = true; maybe_send_stfu(peer); } /* Returns true if we queued this for later handling (steals if true) */ static bool handle_master_request_later(struct peer *peer, const u8 *msg) { if (peer->stfu) { msg_enqueue(peer->update_queue, take(msg)); return true; } return false; } static bool channel_type_eq(const struct channel_type *a, const struct channel_type *b) { return featurebits_eq(a->features, b->features); } static bool match_type(const struct channel_type *desired, const struct channel_type *current, struct channel_type **upgradable) { /* Missing fields are possible. */ if (!desired || !current) return false; if (channel_type_eq(desired, current)) return true; for (size_t i = 0; i < tal_count(upgradable); i++) { if (channel_type_eq(desired, upgradable[i])) return true; } return false; } static void set_channel_type(struct channel *channel, const struct channel_type *type) { const struct channel_type *cur = channel_type(tmpctx, channel); if (channel_type_eq(cur, type)) return; /* We only allow one upgrade at the moment, so that's it. */ assert(!channel->option_static_remotekey); assert(feature_offered(type->features, OPT_STATIC_REMOTEKEY)); /* Do upgrade, tell master. */ channel->option_static_remotekey = true; status_unusual("Upgraded channel to [%s]", fmt_featurebits(tmpctx, type->features)); wire_sync_write(MASTER_FD, take(towire_channeld_upgraded(NULL, true))); } #else /* !EXPERIMENTAL_FEATURES */ static bool handle_master_request_later(struct peer *peer, const u8 *msg) { return false; } static void maybe_send_stfu(struct peer *peer) { } #endif /* 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, advertized_htlc_max(peer->channel)); wire_sync_write(peer->pps->gossip_fd, take(msg)); } /* Get the latest channel update for this channel from gossipd */ static const u8 *get_local_channel_update(const tal_t *ctx, struct peer *peer) { const u8 *msg; msg = towire_gossipd_get_update(NULL, &peer->short_channel_ids[LOCAL]); wire_sync_write(peer->pps->gossip_fd, take(msg)); /* Wait for reply to come back; handle other gossipd msgs meanwhile */ while ((msg = wire_sync_read(tmpctx, peer->pps->gossip_fd)) != NULL) { u8 *update; if (fromwire_gossipd_get_update_reply(ctx, msg, &update)) return update; handle_gossip_msg(peer->pps, take(msg)); } /* Gossipd hangs up on us to kill us when a new * connection comes in. */ peer_failed_connection_lost(); } /** * 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; const u8 *ann; const u8 *annfeatures = get_agreed_channelfeatures(tmpctx, peer->our_features, peer->their_features); ann = private_channel_announcement(tmpctx, &peer->short_channel_ids[LOCAL], &peer->node_ids[LOCAL], &peer->node_ids[REMOTE], annfeatures); /* Tell gossipd about local channel. */ msg = towire_gossip_store_private_channel(NULL, peer->channel->funding, ann); wire_sync_write(peer->pps->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; struct pubkey mykey; status_debug("Exchanging announcement signatures."); ca = create_channel_announcement(tmpctx, peer); req = towire_hsmd_cannouncement_sig_req(tmpctx, ca); msg = hsm_req(tmpctx, req); if (!fromwire_hsmd_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 (!pubkey_from_node_id(&mykey, &peer->node_ids[LOCAL])) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not convert my id '%s' to pubkey", type_to_string(tmpctx, struct node_id, &peer->node_ids[LOCAL])); if (!check_signed_hash(&hash, &peer->announcement_node_sigs[LOCAL], &mykey)) { /* 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->pps, 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 = get_agreed_channelfeatures(tmpctx, peer->our_features, peer->their_features); 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, &chainparams->genesis_blockhash, &peer->short_channel_ids[LOCAL], &peer->node_ids[first], &peer->node_ids[second], &peer->channel->funding_pubkey[first], &peer->channel->funding_pubkey[second]); 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_warn(peer->pps, &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; cannounce = create_channel_announcement(tmpctx, peer); wire_sync_write(peer->pps->gossip_fd, take(towire_gossipd_local_channel_announcement(NULL, 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]) { /* When we reenable the channel, we will also send the announcement to remote peer, and * receive the remote announcement reply. But we will rebuild the channel with announcement * from the DB directly, other than waiting for the remote announcement reply. */ 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]) { check_short_ids_match(peer); /* After making sure short_channel_ids match, we can send remote * announcement to MASTER. */ wire_sync_write(MASTER_FD, take(towire_channeld_got_announcement(NULL, &peer->announcement_node_sigs[REMOTE], &peer->announcement_bitcoin_sigs[REMOTE]))); /* Give other nodes time to notice new block. */ notleak(new_reltimer(&peer->timers, peer, time_from_sec(GOSSIP_ANNOUNCE_DELAY(dev_fast_gossip)), 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_warn(peer->pps, &peer->channel_id, "Bad funding_locked %s", tal_hex(msg, msg)); if (!channel_id_eq(&chanid, &peer->channel_id)) peer_failed_err(peer->pps, &chanid, "Wrong channel id in %s (expected %s)", tal_hex(tmpctx, msg), type_to_string(msg, struct channel_id, &peer->channel_id)); peer->tx_sigs_allowed = false; peer->funding_locked[REMOTE] = true; wire_sync_write(MASTER_FD, take(towire_channeld_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_warn(peer->pps, &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_err(peer->pps, &chanid, "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 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(ROUTING_INFO_SIZE)]; enum channel_add_err add_err; struct htlc *htlc; #if EXPERIMENTAL_FEATURES struct tlv_update_add_tlvs *tlvs = tlv_update_add_tlvs_new(msg); #endif struct pubkey *blinding = NULL; if (!fromwire_update_add_htlc(msg, &channel_id, &id, &amount, &payment_hash, &cltv_expiry, onion_routing_packet #if EXPERIMENTAL_FEATURES , tlvs #endif )) peer_failed_warn(peer->pps, &peer->channel_id, "Bad peer_add_htlc %s", tal_hex(msg, msg)); #if EXPERIMENTAL_FEATURES blinding = tlvs->blinding; #endif add_err = channel_add_htlc(peer->channel, REMOTE, id, amount, cltv_expiry, &payment_hash, onion_routing_packet, blinding, &htlc, NULL); if (add_err != CHANNEL_ERR_ADD_OK) peer_failed_warn(peer->pps, &peer->channel_id, "Bad peer_add_htlc: %s", channel_add_err_name(add_err)); } /* We don't get upset if they're outside the range, as long as they're * improving (or at least, not getting worse!). */ static bool feerate_same_or_better(const struct channel *channel, u32 feerate, u32 feerate_min, u32 feerate_max) { u32 current = channel_feerate(channel, LOCAL); /* Too low? But is it going upwards? */ if (feerate < feerate_min) return feerate >= current; if (feerate > feerate_max) return feerate <= current; return true; } 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_warn(peer->pps, &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->opener != REMOTE) peer_failed_warn(peer->pps, &peer->channel_id, "update_fee from non-opener?"); status_debug("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_same_or_better(peer->channel, feerate, peer->feerate_min, peer->feerate_max)) peer_failed_warn(peer->pps, &peer->channel_id, "update_fee %u outside range %u-%u" " (currently %u)", feerate, peer->feerate_min, peer->feerate_max, channel_feerate(peer->channel, LOCAL)); /* 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_warn(peer->pps, &peer->channel_id, "update_fee %u unaffordable", feerate); status_debug("peer updated fee to %u", feerate); } static void handle_peer_blockheight_change(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u32 blockheight, current; if (!fromwire_update_blockheight(msg, &channel_id, &blockheight)) peer_failed_warn(peer->pps, &peer->channel_id, "Bad update_blockheight %s", tal_hex(msg, msg)); /* BOLT- #2: * A receiving node: * ... * - if the sender is not the initiator: * - MUST fail the channel. */ if (peer->channel->opener != REMOTE) peer_failed_warn(peer->pps, &peer->channel_id, "update_blockheight from non-opener?"); current = get_blockheight(peer->channel->blockheight_states, peer->channel->opener, LOCAL); status_debug("update_blockheight %u. last update height %u," " our current height %u", blockheight, current, peer->our_blockheight); /* BOLT- #2: * A receiving node: * - if the `update_blockheight` is less than the last * received `blockheight`: * - SHOULD fail the channel. * ... * - if `blockheight` is more than 1008 blocks behind * the current blockheight: * - SHOULD fail the channel */ /* Overflow check */ if (blockheight + 1008 < blockheight) peer_failed_warn(peer->pps, &peer->channel_id, "blockheight + 1008 overflow (%u)", blockheight); /* If they're behind the last one they sent, we just warn and * reconnect, as they might be catching up */ /* FIXME: track for how long they send backwards blockheight? */ if (blockheight < current) peer_failed_warn(peer->pps, &peer->channel_id, "update_blockheight %u older than previous %u", blockheight, current); /* BOLT- #2: * A receiving node: * ... * - if `blockheight` is more than 1008 blocks behind * the current blockheight: * - SHOULD fail the channel */ assert(blockheight < blockheight + 1008); if (blockheight + 1008 < peer->our_blockheight) peer_failed_err(peer->pps, &peer->channel_id, "update_blockheight %u outside" " permissible range", blockheight); channel_update_blockheight(peer->channel, blockheight); status_debug("peer updated blockheight to %u", blockheight); } 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, struct penalty_base *pbase, const struct fee_states *fee_states, const struct height_states *blockheight_states, const struct htlc **changed_htlcs, const struct bitcoin_signature *commit_sig, const struct bitcoin_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_channeld_sending_commitsig(ctx, remote_commit_index, pbase, fee_states, blockheight_states, 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; struct tlv_shutdown_tlvs *tlvs; 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); if (peer->shutdown_wrong_funding) { tlvs = tlv_shutdown_tlvs_new(tmpctx); tlvs->wrong_funding = tal(tlvs, struct tlv_shutdown_tlvs_wrong_funding); tlvs->wrong_funding->txid = peer->shutdown_wrong_funding->txid; tlvs->wrong_funding->outnum = peer->shutdown_wrong_funding->n; } else tlvs = NULL; msg = towire_shutdown(NULL, &peer->channel_id, peer->final_scriptpubkey, tlvs); sync_crypto_write(peer->pps, take(msg)); peer->send_shutdown = false; peer->shutdown_sent[LOCAL] = true; 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_channeld_shutdown_complete(NULL, peer->pps))); per_peer_state_fdpass_send(MASTER_FD, peer->pps); close(MASTER_FD); } /* This queues other traffic from the fd until we get reply. */ static u8 *master_wait_sync_reply(const tal_t *ctx, struct peer *peer, const u8 *msg, int replytype) { u8 *reply; status_debug("Sending master %u", fromwire_peektype(msg)); if (!wire_sync_write(MASTER_FD, msg)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync write to master: %s", strerror(errno)); status_debug("... , awaiting %u", replytype); for (;;) { int type; reply = wire_sync_read(ctx, MASTER_FD); if (!reply) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync read from master: %s", strerror(errno)); type = fromwire_peektype(reply); if (type == replytype) { status_debug("Got it!"); break; } status_debug("Nope, got %u instead", type); msg_enqueue(peer->from_master, take(reply)); } return reply; } /* Returns HTLC sigs, sets commit_sig */ static struct bitcoin_signature *calc_commitsigs(const tal_t *ctx, const struct peer *peer, struct bitcoin_tx **txs, const u8 *funding_wscript, const struct htlc **htlc_map, u64 commit_index, struct bitcoin_signature *commit_sig) { size_t i; struct pubkey local_htlckey; const u8 *msg; struct bitcoin_signature *htlc_sigs; msg = towire_hsmd_sign_remote_commitment_tx(NULL, txs[0], &peer->channel->funding_pubkey[REMOTE], &peer->remote_per_commit, peer->channel->option_static_remotekey); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsmd_sign_tx_reply(msg, commit_sig)) status_failed(STATUS_FAIL_HSM_IO, "Reading sign_remote_commitment_tx reply: %s", tal_hex(tmpctx, msg)); status_debug("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, funding_wscript), 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 the ordering of the commitment transaction */ htlc_sigs = tal_arr(ctx, struct bitcoin_signature, tal_count(txs) - 1); for (i = 0; i < tal_count(htlc_sigs); i++) { u8 *wscript; wscript = bitcoin_tx_output_get_witscript(tmpctx, txs[0], txs[i+1]->wtx->inputs[0].index); msg = towire_hsmd_sign_remote_htlc_tx(NULL, txs[i + 1], wscript, &peer->remote_per_commit, peer->channel->option_anchor_outputs); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsmd_sign_tx_reply(msg, &htlc_sigs[i])) status_failed(STATUS_FAIL_HSM_IO, "Bad sign_remote_htlc_tx reply: %s", tal_hex(tmpctx, msg)); status_debug("Creating HTLC signature %s for tx %s wscript %s key %s", type_to_string(tmpctx, struct bitcoin_signature, &htlc_sigs[i]), type_to_string(tmpctx, struct bitcoin_tx, txs[1+i]), tal_hex(tmpctx, wscript), type_to_string(tmpctx, struct pubkey, &local_htlckey)); assert(check_tx_sig(txs[1+i], 0, NULL, wscript, &local_htlckey, &htlc_sigs[i])); } 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->pps, take(make_ping(NULL, 1, 0))); peer->expecting_pong = true; } /* Peer protocol doesn't want sighash flags. */ static secp256k1_ecdsa_signature *raw_sigs(const tal_t *ctx, const struct bitcoin_signature *sigs) { secp256k1_ecdsa_signature *raw; raw = tal_arr(ctx, secp256k1_ecdsa_signature, tal_count(sigs)); for (size_t i = 0; i < tal_count(sigs); i++) raw[i] = sigs[i].s; return raw; } static struct bitcoin_signature *unraw_sigs(const tal_t *ctx, const secp256k1_ecdsa_signature *raw, bool option_anchor_outputs) { struct bitcoin_signature *sigs; sigs = tal_arr(ctx, struct bitcoin_signature, tal_count(raw)); for (size_t i = 0; i < tal_count(raw); i++) { sigs[i].s = raw[i]; /* BOLT #3: * ## HTLC-Timeout and HTLC-Success Transactions *... * * if `option_anchor_outputs` applies to this commitment * transaction, `SIGHASH_SINGLE|SIGHASH_ANYONECANPAY` is * used. */ if (option_anchor_outputs) sigs[i].sighash_type = SIGHASH_SINGLE|SIGHASH_ANYONECANPAY; else sigs[i].sighash_type = SIGHASH_ALL; } return sigs; } /* Do we want to update fees? */ static bool want_fee_update(const struct peer *peer, u32 *target) { u32 current, val; if (peer->channel->opener != LOCAL) return false; #if EXPERIMENTAL_FEATURES /* No fee update while quiescing! */ if (peer->stfu) return false; #endif current = channel_feerate(peer->channel, REMOTE); /* max is *approximate*: only take it into account if we're * trying to increase feerate. */ if (peer->desired_feerate > current) { /* FIXME: We should avoid adding HTLCs until we can meet this * feerate! */ u32 max = approx_max_feerate(peer->channel); val = peer->desired_feerate; /* Respect max, but don't let us *decrease* us */ if (val > max) val = max; if (val < current) val = current; } else val = peer->desired_feerate; if (target) *target = val; return val != current; } /* Do we want to update blockheight? */ static bool want_blockheight_update(const struct peer *peer, u32 *height) { u32 last; if (peer->channel->opener != LOCAL) return false; if (peer->channel->lease_expiry == 0) return false; #if EXPERIMENTAL_FEATURES /* No fee update while quiescing! */ if (peer->stfu) return false; #endif /* What's the current blockheight */ last = get_blockheight(peer->channel->blockheight_states, peer->channel->opener, LOCAL); if (peer->our_blockheight < last) { status_broken("current blockheight %u less than last %u", peer->our_blockheight, last); return false; } if (peer->our_blockheight == last) return false; if (height) *height = peer->our_blockheight; return true; } static void send_commit(struct peer *peer) { u8 *msg; const struct htlc **changed_htlcs; struct bitcoin_signature commit_sig, *htlc_sigs; struct bitcoin_tx **txs; const u8 *funding_wscript; const struct htlc **htlc_map; struct wally_tx_output *direct_outputs[NUM_SIDES]; struct penalty_base *pbase; u32 our_blockheight; u32 feerate_target; #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_debug("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_debug("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 (want_fee_update(peer, &feerate_target)) { /* FIXME: We occasionally desynchronize with LND here, so * don't stress things by having more than one feerate change * in-flight! */ if (feerate_changes_done(peer->channel->fee_states, false)) { u8 *msg; if (!channel_update_feerate(peer->channel, feerate_target)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not afford feerate %u" " (vs max %u)", feerate_target, approx_max_feerate(peer->channel)); msg = towire_update_fee(NULL, &peer->channel_id, feerate_target); sync_crypto_write(peer->pps, take(msg)); } } if (want_blockheight_update(peer, &our_blockheight)) { if (blockheight_changes_done(peer->channel->blockheight_states, false)) { u8 *msg; channel_update_blockheight(peer->channel, our_blockheight); msg = towire_update_blockheight(NULL, &peer->channel_id, our_blockheight); sync_crypto_write(peer->pps, 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_debug("Can't send commit: nothing to send," " feechange %s (%s)" " blockheight %s (%s)", want_fee_update(peer, NULL) ? "wanted": "not wanted", type_to_string(tmpctx, struct fee_states, peer->channel->fee_states), want_blockheight_update(peer, NULL) ? "wanted" : "not wanted", type_to_string(tmpctx, struct height_states, peer->channel->blockheight_states)); /* Covers the case where we've just been told to shutdown. */ maybe_send_shutdown(peer); peer->commit_timer = NULL; return; } txs = channel_txs(tmpctx, &htlc_map, direct_outputs, &funding_wscript, peer->channel, &peer->remote_per_commit, peer->next_index[REMOTE], REMOTE); htlc_sigs = calc_commitsigs(tmpctx, peer, txs, funding_wscript, htlc_map, peer->next_index[REMOTE], &commit_sig); if (direct_outputs[LOCAL] != NULL) { pbase = penalty_base_new(tmpctx, peer->next_index[REMOTE], txs[0], direct_outputs[LOCAL]); /* Add the penalty_base to our in-memory list as well, so we * can find it again later. */ tal_arr_expand(&peer->pbases, tal_steal(peer, pbase)); } else pbase = NULL; status_debug("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], pbase, peer->channel->fee_states, peer->channel->blockheight_states, changed_htlcs, &commit_sig, htlc_sigs); /* Message is empty; receiving it is the point. */ master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNELD_SENDING_COMMITSIG_REPLY); status_debug("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, raw_sigs(tmpctx, htlc_sigs)); sync_crypto_write_no_delay(peer->pps, 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_hsmd_get_per_commitment_point(NULL, index))); if (!fromwire_hsmd_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); } /* Convert changed htlcs into parts which lightningd expects. */ static void marshall_htlc_info(const tal_t *ctx, const struct htlc **changed_htlcs, struct changed_htlc **changed, struct fulfilled_htlc **fulfilled, const struct failed_htlc ***failed, struct added_htlc **added) { *changed = tal_arr(ctx, struct changed_htlc, 0); *added = tal_arr(ctx, struct added_htlc, 0); *failed = tal_arr(ctx, const struct failed_htlc *, 0); *fulfilled = tal_arr(ctx, 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; 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)); if (htlc->blinding) { a.blinding = htlc->blinding; ecdh(a.blinding, &a.blinding_ss); } else a.blinding = NULL; tal_arr_expand(added, a); } else if (htlc->state == RCVD_REMOVE_COMMIT) { if (htlc->r) { struct fulfilled_htlc f; assert(!htlc->failed); f.id = htlc->id; f.payment_preimage = *htlc->r; tal_arr_expand(fulfilled, f); } else { assert(!htlc->r); tal_arr_expand(failed, htlc->failed); } } 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); } } } static void send_revocation(struct peer *peer, const struct bitcoin_signature *commit_sig, const struct bitcoin_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; const u8 *msg_for_master; /* Marshall it now before channel_sending_revoke_and_ack changes htlcs */ /* FIXME: Make infrastructure handle state post-revoke_and_ack! */ marshall_htlc_info(tmpctx, changed_htlcs, &changed, &fulfilled, &failed, &added); /* 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_debug("revoke_and_ack made pending: commit timer"); start_commit_timer(peer); } /* Tell master daemon about commitsig (and by implication, that we're * sending revoke_and_ack), then wait for it to ack. */ /* We had to do this after channel_sending_revoke_and_ack, since we * want it to save the fee_states produced there. */ msg_for_master = towire_channeld_got_commitsig(NULL, peer->next_index[LOCAL] - 1, peer->channel->fee_states, peer->channel->blockheight_states, commit_sig, htlc_sigs, added, fulfilled, failed, changed, committx); master_wait_sync_reply(tmpctx, peer, take(msg_for_master), WIRE_CHANNELD_GOT_COMMITSIG_REPLY); /* Now we can finally send revoke_and_ack to peer */ sync_crypto_write_no_delay(peer->pps, take(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 *raw_sigs; struct bitcoin_signature *htlc_sigs; struct pubkey remote_htlckey; struct bitcoin_tx **txs; const struct htlc **htlc_map, **changed_htlcs; const u8 *funding_wscript; 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. */ status_debug("Oh hi LND! Empty commitment at #%"PRIu64, peer->next_index[LOCAL]); if (peer->last_empty_commitment == peer->next_index[LOCAL] - 1) peer_failed_warn(peer->pps, &peer->channel_id, "commit_sig with no changes (again!)"); peer->last_empty_commitment = peer->next_index[LOCAL]; } /* We were supposed to check this was affordable as we go. */ if (peer->channel->opener == REMOTE) { status_debug("Feerates are %u/%u", channel_feerate(peer->channel, LOCAL), channel_feerate(peer->channel, REMOTE)); assert(can_opener_afford_feerate(peer->channel, channel_feerate(peer->channel, LOCAL))); } if (!fromwire_commitment_signed(tmpctx, msg, &channel_id, &commit_sig.s, &raw_sigs)) peer_failed_warn(peer->pps, &peer->channel_id, "Bad commit_sig %s", tal_hex(msg, msg)); /* SIGHASH_ALL is implied. */ commit_sig.sighash_type = SIGHASH_ALL; htlc_sigs = unraw_sigs(tmpctx, raw_sigs, peer->channel->option_anchor_outputs); txs = channel_txs(tmpctx, &htlc_map, NULL, &funding_wscript, peer->channel, &peer->next_local_per_commit, peer->next_index[LOCAL], LOCAL); /* Set the commit_sig on the commitment tx psbt */ if (!psbt_input_set_signature(txs[0]->psbt, 0, &peer->channel->funding_pubkey[REMOTE], &commit_sig)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Unable to set signature internally"); 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_debug("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 * OR non-compliant with LOW-S-standard rule...: * - MUST fail the channel. */ if (!check_tx_sig(txs[0], 0, NULL, funding_wscript, &peer->channel->funding_pubkey[REMOTE], &commit_sig)) { dump_htlcs(peer->channel, "receiving commit_sig"); peer_failed_warn(peer->pps, &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, funding_wscript), type_to_string(msg, struct pubkey, &peer->channel->funding_pubkey [REMOTE]), channel_feerate(peer->channel, LOCAL)); } /* 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_warn(peer->pps, &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 OR non-compliant with LOW-S-standard rule...: * - MUST fail the channel. */ for (i = 0; i < tal_count(htlc_sigs); i++) { u8 *wscript; wscript = bitcoin_tx_output_get_witscript(tmpctx, txs[0], txs[i+1]->wtx->inputs[0].index); if (!check_tx_sig(txs[1+i], 0, NULL, wscript, &remote_htlckey, &htlc_sigs[i])) peer_failed_warn(peer->pps, &peer->channel_id, "Bad commit_sig signature %s for htlc %s wscript %s key %s", type_to_string(msg, struct bitcoin_signature, &htlc_sigs[i]), type_to_string(msg, struct bitcoin_tx, txs[1+i]), tal_hex(msg, wscript), type_to_string(msg, struct pubkey, &remote_htlckey)); } status_debug("Received commit_sig with %zu htlc sigs", tal_count(htlc_sigs)); send_revocation(peer, &commit_sig, htlc_sigs, changed_htlcs, txs[0]); /* We may now be quiescent on our side. */ maybe_send_stfu(peer); /* This might have synced the feerates: if so, we may want to * update */ if (want_fee_update(peer, NULL)) start_commit_timer(peer); } /* Pops the penalty base for the given commitnum from our internal list. There * may not be one, in which case we return NULL and leave the list * unmodified. */ static struct penalty_base * penalty_base_by_commitnum(const tal_t *ctx, struct peer *peer, u64 commitnum) { struct penalty_base *res = NULL; for (size_t i = 0; i < tal_count(peer->pbases); i++) { if (peer->pbases[i]->commitment_num == commitnum) { res = tal_steal(ctx, peer->pbases[i]); tal_arr_remove(&peer->pbases, i); break; } } return res; } static u8 *got_revoke_msg(struct peer *peer, u64 revoke_num, const struct secret *per_commitment_secret, const struct pubkey *next_per_commit_point, const struct htlc **changed_htlcs, const struct fee_states *fee_states, const struct height_states *blockheight_states) { u8 *msg; struct penalty_base *pbase; struct changed_htlc *changed = tal_arr(tmpctx, struct changed_htlc, 0); const struct bitcoin_tx *ptx = NULL; for (size_t i = 0; i < tal_count(changed_htlcs); i++) { struct changed_htlc c; const struct htlc *htlc = changed_htlcs[i]; status_debug("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); } pbase = penalty_base_by_commitnum(tmpctx, peer, revoke_num); if (pbase) { ptx = penalty_tx_create( NULL, peer->channel, peer->feerate_penalty, peer->final_scriptpubkey, per_commitment_secret, &pbase->txid, pbase->outnum, pbase->amount, HSM_FD); } msg = towire_channeld_got_revoke(peer, revoke_num, per_commitment_secret, next_per_commit_point, fee_states, blockheight_states, changed, pbase, ptx); tal_free(ptx); 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_warn(peer->pps, &peer->channel_id, "Bad revoke_and_ack %s", tal_hex(msg, msg)); } if (peer->revocations_received != peer->next_index[REMOTE] - 2) { peer_failed_warn(peer->pps, &peer->channel_id, "Unexpected revoke_and_ack"); } /* BOLT #2: * * A receiving node: * - if `per_commitment_secret` is not a valid secret key or 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_warn(peer->pps, &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_err(peer->pps, &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_debug("Commits outstanding after recv revoke_and_ack"); else status_debug("No commits outstanding after recv revoke_and_ack"); /* Tell master about things this locks in, wait for response */ msg = got_revoke_msg(peer, peer->revocations_received++, &old_commit_secret, &next_per_commit, changed_htlcs, peer->channel->fee_states, peer->channel->blockheight_states); master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNELD_GOT_REVOKE_REPLY); peer->old_remote_per_commit = peer->remote_per_commit; peer->remote_per_commit = next_per_commit; status_debug("revoke_and_ack %s: remote_per_commit = %s, old_remote_per_commit = %s", side_to_str(peer->channel->opener), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit)); /* We may now be quiescent on our side. */ maybe_send_stfu(peer); 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_warn(peer->pps, &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_warn(peer->pps, &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; struct failed_htlc *f; /* reason is not an onionreply because spec doesn't know about that */ if (!fromwire_update_fail_htlc(msg, msg, &channel_id, &id, &reason)) { peer_failed_warn(peer->pps, &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: { htlc->failed = f = tal(htlc, struct failed_htlc); f->id = id; f->sha256_of_onion = NULL; f->onion = new_onionreply(f, take(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_warn(peer->pps, &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; struct failed_htlc *f; if (!fromwire_update_fail_malformed_htlc(msg, &channel_id, &id, &sha256_of_onion, &failure_code)) { peer_failed_warn(peer->pps, &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_warn(peer->pps, &peer->channel_id, "Bad update_fail_malformed_htlc failure code %u", failure_code); } e = channel_fail_htlc(peer->channel, LOCAL, id, &htlc); switch (e) { case CHANNEL_ERR_REMOVE_OK: htlc->failed = f = tal(htlc, struct failed_htlc); f->id = id; f->onion = NULL; f->sha256_of_onion = tal_dup(f, struct sha256, &sha256_of_onion); f->badonion = 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_warn(peer->pps, &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; struct tlv_shutdown_tlvs *tlvs = tlv_shutdown_tlvs_new(tmpctx); struct bitcoin_outpoint *wrong_funding; /* Disable the channel. */ send_channel_update(peer, ROUTING_FLAGS_DISABLED); if (!fromwire_shutdown(tmpctx, shutdown, &channel_id, &scriptpubkey, tlvs)) peer_failed_warn(peer->pps, &peer->channel_id, "Bad shutdown %s", tal_hex(peer, shutdown)); /* FIXME: We shouldn't let them initiate a shutdown while the * channel is active (if we leased funds) */ /* BOLT #2: * * - if both nodes advertised the `option_upfront_shutdown_script` * feature, and the receiving node received a non-zero-length * `shutdown_scriptpubkey` in `open_channel` or `accept_channel`, and * that `shutdown_scriptpubkey` is not equal to `scriptpubkey`: * - MUST fail the connection. */ /* openingd only sets this if feature was negotiated at opening. */ if (tal_count(peer->remote_upfront_shutdown_script) && !memeq(scriptpubkey, tal_count(scriptpubkey), peer->remote_upfront_shutdown_script, tal_count(peer->remote_upfront_shutdown_script))) peer_failed_err(peer->pps, &peer->channel_id, "scriptpubkey %s is not as agreed upfront (%s)", tal_hex(peer, scriptpubkey), tal_hex(peer, peer->remote_upfront_shutdown_script)); /* We only accept an wrong_funding if: * 1. It was negotiated. * 2. It's not dual-funding. * 3. They opened it. * 4. The channel was never used. */ if (tlvs->wrong_funding) { if (!feature_negotiated(peer->our_features, peer->their_features, OPT_SHUTDOWN_WRONG_FUNDING)) peer_failed_warn(peer->pps, &peer->channel_id, "wrong_funding shutdown needs" " feature %u", OPT_SHUTDOWN_WRONG_FUNDING); if (feature_negotiated(peer->our_features, peer->their_features, OPT_DUAL_FUND)) peer_failed_warn(peer->pps, &peer->channel_id, "wrong_funding shutdown invalid" " with dual-funding"); if (peer->channel->opener != REMOTE) peer_failed_warn(peer->pps, &peer->channel_id, "No shutdown wrong_funding" " for channels we opened!"); if (peer->next_index[REMOTE] != 1 || peer->next_index[LOCAL] != 1) peer_failed_warn(peer->pps, &peer->channel_id, "No shutdown wrong_funding" " for used channels!"); /* Turn into our outpoint type. */ wrong_funding = tal(tmpctx, struct bitcoin_outpoint); wrong_funding->txid = tlvs->wrong_funding->txid; wrong_funding->n = tlvs->wrong_funding->outnum; } else { wrong_funding = NULL; } /* Tell master: we don't have to wait because on reconnect other end * will re-send anyway. */ wire_sync_write(MASTER_FD, take(towire_channeld_got_shutdown(NULL, scriptpubkey, wrong_funding))); 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); } /* Try to handle a custommsg Returns true if it was a custom message and has * been handled, false if the message was not handled. */ static bool channeld_handle_custommsg(const u8 *msg) { enum peer_wire type = fromwire_peektype(msg); if (type % 2 == 1 && !peer_wire_is_defined(type)) { /* The message is not part of the messages we know how to * handle. Assuming this is a custommsg, we just forward it to the * master. */ wire_sync_write(MASTER_FD, take(towire_custommsg_in(NULL, msg))); return true; } else { return false; } } static void handle_unexpected_tx_sigs(struct peer *peer, const u8 *msg) { const struct witness_stack **ws; struct channel_id cid; struct bitcoin_txid txid; /* In a rare case, a v2 peer may re-send a tx_sigs message. * This happens when they've/we've exchanged funding_locked, * but they did not receive our funding_locked. */ if (!fromwire_tx_signatures(tmpctx, msg, &cid, &txid, cast_const3(struct witness_stack ***, &ws))) peer_failed_warn(peer->pps, &peer->channel_id, "Bad tx_signatures %s", tal_hex(msg, msg)); status_info("Unexpected `tx_signatures` from peer. %s", peer->tx_sigs_allowed ? "Allowing." : "Failing."); if (!peer->tx_sigs_allowed) peer_failed_warn(peer->pps, &peer->channel_id, "Unexpected `tx_signatures`"); peer->tx_sigs_allowed = false; } static void handle_unexpected_reestablish(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 next_commitment_number; u64 next_revocation_number; struct secret your_last_per_commitment_secret; struct pubkey my_current_per_commitment_point; #if EXPERIMENTAL_FEATURES struct tlv_channel_reestablish_tlvs *tlvs = tlv_channel_reestablish_tlvs_new(tmpctx); #endif if (!fromwire_channel_reestablish(msg, &channel_id, &next_commitment_number, &next_revocation_number, &your_last_per_commitment_secret, &my_current_per_commitment_point #if EXPERIMENTAL_FEATURES , tlvs #endif )) peer_failed_warn(peer->pps, &peer->channel_id, "Bad channel_reestablish %s", tal_hex(peer, msg)); /* Is it the same as the peer channel ID? */ if (channel_id_eq(&channel_id, &peer->channel_id)) { /* Log this event as unusual. */ status_unusual("Got repeated WIRE_CHANNEL_REESTABLISH " "for channel %s, ignoring: %s", type_to_string(tmpctx, struct channel_id, &peer->channel_id), tal_hex(tmpctx, msg)); /* This is a mitigation for a known bug in some peer software * that sometimes double-sends a reestablish message. * * Ideally we would send some kind of `error` message to the * peer here, but if we sent an `error` message with the * same channel ID it would cause the peer to drop the * channel unilaterally. * We also cannot use 0x00...00 because that means "all * channels", so a proper peer (like C-lightning) will * unilaterally close all channels we have with it, if we * sent the 0x00...00 channel ID. * * So just do not send an error. */ return; } /* We only support one channel here, so the unexpected channel is the * peer getting its wires crossed somewhere. * Fail the channel they sent, not the channel we are actively * handling. */ peer_failed_err(peer->pps, &channel_id, "Peer sent unexpected message %u, (%s) " "for nonexistent channel %s", WIRE_CHANNEL_REESTABLISH, "WIRE_CHANNEL_REESTABLISH", type_to_string(tmpctx, struct channel_id, &channel_id)); } static void peer_in(struct peer *peer, const u8 *msg) { enum peer_wire type = fromwire_peektype(msg); /* Only count soft errors if the channel has locked-in already; * otherwise we can't cancel a channel before it has opened. */ bool soft_error = peer->funding_locked[REMOTE] || peer->funding_locked[LOCAL]; peer->last_recv = time_now(); /* Catch our own ping replies. */ if (type == WIRE_PONG && peer->expecting_pong) { peer->expecting_pong = false; return; } if (channeld_handle_custommsg(msg)) return; /* Since LND seems to send errors which aren't actually fatal events, * we treat errors here as soft. */ if (handle_peer_gossip_or_error(peer->pps, &peer->channel_id, soft_error, 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 /* We expect these for v2 !! */ && type != WIRE_TX_SIGNATURES /* lnd sends these early; it's harmless. */ && type != WIRE_UPDATE_FEE && type != WIRE_ANNOUNCEMENT_SIGNATURES) { peer_failed_warn(peer->pps, &peer->channel_id, "%s (%u) before funding locked", peer_wire_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_UPDATE_BLOCKHEIGHT: handle_peer_blockheight_change(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; #if EXPERIMENTAL_FEATURES case WIRE_STFU: handle_stfu(peer, msg); return; #endif case WIRE_INIT: case WIRE_OPEN_CHANNEL: case WIRE_ACCEPT_CHANNEL: case WIRE_FUNDING_CREATED: case WIRE_FUNDING_SIGNED: case WIRE_CLOSING_SIGNED: case WIRE_TX_ADD_INPUT: case WIRE_TX_REMOVE_INPUT: case WIRE_TX_ADD_OUTPUT: case WIRE_TX_REMOVE_OUTPUT: case WIRE_TX_COMPLETE: case WIRE_OPEN_CHANNEL2: case WIRE_ACCEPT_CHANNEL2: case WIRE_TX_SIGNATURES: handle_unexpected_tx_sigs(peer, msg); return; case WIRE_INIT_RBF: case WIRE_ACK_RBF: break; case WIRE_CHANNEL_REESTABLISH: handle_unexpected_reestablish(peer, msg); return; /* 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_WARNING: case WIRE_ERROR: case WIRE_ONION_MESSAGE: abort(); } peer_failed_warn(peer->pps, &peer->channel_id, "Peer sent unknown message %u (%s)", type, peer_wire_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->pps, take(msg)); } static void send_fail_or_fulfill(struct peer *peer, const struct htlc *h) { u8 *msg; if (h->failed) { const struct failed_htlc *f = h->failed; if (f->sha256_of_onion) { msg = towire_update_fail_malformed_htlc(NULL, &peer->channel_id, h->id, f->sha256_of_onion, f->badonion); } else { msg = towire_update_fail_htlc(peer, &peer->channel_id, h->id, f->onion->contents); } } else if (h->r) { msg = towire_update_fulfill_htlc(NULL, &peer->channel_id, h->id, h->r); } else peer_failed_warn(peer->pps, &peer->channel_id, "HTLC %"PRIu64" state %s not failed/fulfilled", h->id, htlc_state_name(h->state)); sync_crypto_write(peer->pps, take(msg)); } static int cmp_changed_htlc_id(const struct changed_htlc *a, const struct changed_htlc *b, void *unused) { /* ids can be the same (sender and receiver are indep) but in * that case we don't care about order. */ if (a->id > b->id) return 1; else if (a->id < b->id) return -1; return 0; } static void resend_commitment(struct peer *peer, struct changed_htlc *last) { size_t i; struct bitcoin_signature commit_sig, *htlc_sigs; u8 *msg; struct bitcoin_tx **txs; const u8 *funding_wscript; const struct htlc **htlc_map; struct wally_tx_output *direct_outputs[NUM_SIDES]; status_debug("Retransmitting commitment, feerate LOCAL=%u REMOTE=%u," " blockheight LOCAL=%u REMOTE=%u", channel_feerate(peer->channel, LOCAL), channel_feerate(peer->channel, REMOTE), channel_blockheight(peer->channel, LOCAL), channel_blockheight(peer->channel, REMOTE)); /* Note that HTLCs must be *added* in order. Simplest thing to do * is to sort them all into ascending ID order here (we could do * this when we save them in channel_sending_commit, but older versions * won't have them sorted in the db, so doing it here is better). */ asort(last, tal_count(last), cmp_changed_htlc_id, NULL); /* BOLT #2: * * - if `next_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. */ /* We need to send fulfills/failures before adds, so we split them * up into two loops -- this is the 'fulfill/fail' loop */ 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_warn(peer->pps, &peer->channel_id, "Can't find HTLC %"PRIu64" to resend", last[i].id); if (h->state == SENT_REMOVE_COMMIT) send_fail_or_fulfill(peer, h); } /* We need to send fulfills/failures before adds, so we split them * up into two loops -- this is the 'add' loop */ 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_warn(peer->pps, &peer->channel_id, "Can't find HTLC %"PRIu64" to resend", last[i].id); if (h->state == SENT_ADD_COMMIT) { #if EXPERIMENTAL_FEATURES struct tlv_update_add_tlvs *tlvs; if (h->blinding) { tlvs = tlv_update_add_tlvs_new(tmpctx); tlvs->blinding = tal_dup(tlvs, struct pubkey, h->blinding); } else tlvs = NULL; #endif u8 *msg = towire_update_add_htlc(NULL, &peer->channel_id, h->id, h->amount, &h->rhash, abs_locktime_to_blocks( &h->expiry), h->routing #if EXPERIMENTAL_FEATURES , tlvs #endif ); sync_crypto_write(peer->pps, take(msg)); } } /* Make sure they have the correct fee and blockheight. */ if (peer->channel->opener == LOCAL) { msg = towire_update_fee(NULL, &peer->channel_id, channel_feerate(peer->channel, REMOTE)); sync_crypto_write(peer->pps, take(msg)); if (peer->channel->lease_expiry > 0) { msg = towire_update_blockheight(NULL, &peer->channel_id, channel_blockheight(peer->channel, REMOTE)); sync_crypto_write(peer->pps, take(msg)); } } /* Re-send the commitment_signed itself. */ txs = channel_txs(tmpctx, &htlc_map, direct_outputs, &funding_wscript, peer->channel, &peer->remote_per_commit, peer->next_index[REMOTE]-1, REMOTE); htlc_sigs = calc_commitsigs(tmpctx, peer, txs, funding_wscript, htlc_map, peer->next_index[REMOTE]-1, &commit_sig); msg = towire_commitment_signed(NULL, &peer->channel_id, &commit_sig.s, raw_sigs(tmpctx, htlc_sigs)); sync_crypto_write(peer->pps, 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 `option_static_remotekey` applies to the commitment transaction: * - if `next_revocation_number` is greater than expected above, AND * `your_last_per_commitment_secret` is correct for that * `next_revocation_number` minus 1: *... * - otherwise, if it supports `option_data_loss_protect`: * - if `next_revocation_number` is greater than expected above, * AND `your_last_per_commitment_secret` is correct for that * `next_revocation_number` minus 1: */ static void check_future_dataloss_fields(struct peer *peer, u64 next_revocation_number, const struct secret *last_local_per_commit_secret, /* This is NULL if option_static_remotekey */ const struct pubkey *remote_current_per_commitment_point) { const u8 *msg; bool correct; assert(next_revocation_number > peer->next_index[LOCAL] - 1); msg = towire_hsmd_check_future_secret(NULL, next_revocation_number - 1, last_local_per_commit_secret); msg = hsm_req(tmpctx, take(msg)); if (!fromwire_hsmd_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_err(peer->pps, &peer->channel_id, "bad future last_local_per_commit_secret: %"PRIu64 " vs %"PRIu64, next_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_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_channeld_fail_fallen_behind(NULL, remote_current_per_commitment_point))); /* We have to send them an error to trigger dropping to chain. */ peer_failed_err(peer->pps, &peer->channel_id, "Awaiting unilateral close"); } /* BOLT #2: * * A receiving node: * - if `option_static_remotekey` applies to the commitment transaction: * ... * - if `your_last_per_commitment_secret` does not match the expected values: * - SHOULD fail the channel. * - otherwise, if it supports `option_data_loss_protect`: *... * - 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_revocation_number, u64 next_commitment_number, const struct secret *last_local_per_commit_secret, /* NULL if option_static_remotekey */ 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_revocation_number == peer->next_index[LOCAL] - 2 || next_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_commitment_number == peer->next_index[REMOTE] || next_commitment_number == peer->next_index[REMOTE] - 1); if (!last_local_per_commit_secret) return; /* BOLT #2: * - if `next_revocation_number` equals 0: * - MUST set `your_last_per_commitment_secret` to all zeroes */ status_debug("next_revocation_number = %"PRIu64, next_revocation_number); if (next_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_revocation_number+1, &unused, &old_commit_secret); } if (!secret_eq_consttime(&old_commit_secret, last_local_per_commit_secret)) peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish: your_last_per_commitment_secret %"PRIu64 ": %s should be %s", next_revocation_number, type_to_string(tmpctx, struct secret, last_local_per_commit_secret), type_to_string(tmpctx, struct secret, &old_commit_secret)); if (!remote_current_per_commitment_point) { status_debug("option_static_remotekey: fields are correct"); return; } status_debug("Reestablish, comparing commitments. Remote's next local commitment number" " is %"PRIu64". Our next remote is %"PRIu64" with %"PRIu64 " revocations received", next_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_commitment_number == peer->revocations_received + 1) { if (!pubkey_eq(remote_current_per_commitment_point, &peer->old_remote_per_commit)) { peer_failed_warn(peer->pps, &peer->channel_id, "bad reestablish: remote's " "my_current_per_commitment_point %"PRIu64 "is %s; expected %s (new is %s).", next_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_warn(peer->pps, &peer->channel_id, "bad reestablish: remote's " "my_current_per_commitment_point %"PRIu64 "is %s; expected %s (old is %s).", next_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_debug("option_data_loss_protect: fields are correct"); } /* Older LND sometimes sends funding_locked before reestablish! */ /* ... or announcement_signatures. Sigh, let's handle whatever they send. */ static bool capture_premature_msg(const u8 ***shit_lnd_says, const u8 *msg) { if (fromwire_peektype(msg) == WIRE_CHANNEL_REESTABLISH) return false; /* Don't allow infinite memory consumption. */ if (tal_count(*shit_lnd_says) > 10) return false; status_debug("Stashing early %s msg!", peer_wire_name(fromwire_peektype(msg))); tal_arr_expand(shit_lnd_says, tal_steal(*shit_lnd_says, msg)); return true; } static void peer_reconnect(struct peer *peer, const struct secret *last_remote_per_commit_secret, u8 *reestablish_only) { struct channel_id channel_id; /* Note: BOLT #2 uses these names! */ u64 next_commitment_number, next_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, check_extra_fields; const u8 **premature_msgs = tal_arr(peer, const u8 *, 0); #if EXPERIMENTAL_FEATURES struct tlv_channel_reestablish_tlvs *send_tlvs, *recv_tlvs; #endif dataloss_protect = feature_negotiated(peer->our_features, peer->their_features, OPT_DATA_LOSS_PROTECT); /* Both these options give us extra fields to check. */ check_extra_fields = dataloss_protect || peer->channel->option_static_remotekey; /* 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); #if EXPERIMENTAL_FEATURES /* Subtle: we free tmpctx below as we loop, so tal off peer */ send_tlvs = tlv_channel_reestablish_tlvs_new(peer); /* BOLT-upgrade_protocol #2: * A node sending `channel_reestablish`, if it supports upgrading channels: * - MUST set `next_to_send` the commitment number of the next * `commitment_signed` it expects to send. */ send_tlvs->next_to_send = tal_dup(send_tlvs, u64, &peer->next_index[REMOTE]); /* BOLT-upgrade_protocol #2: * - if it initiated the channel: * - MUST set `desired_type` to the channel_type it wants for the * channel. */ if (peer->channel->opener == LOCAL) send_tlvs->desired_type = channel_desired_type(send_tlvs, peer->channel); else { /* BOLT-upgrade_protocol #2: * - otherwise: * - MUST set `current_type` to the current channel_type of the * channel. * - MUST set `upgradable` to the channel types it could change * to. * - MAY not set `upgradable` if it would be empty. */ send_tlvs->current_type = channel_type(send_tlvs, peer->channel); send_tlvs->upgradable = channel_upgradable_types(send_tlvs, peer->channel); } #endif /* 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_commitment_number` to the commitment number * of the next `commitment_signed` it expects to receive. * - MUST set `next_revocation_number` to the commitment number * of the next `revoke_and_ack` message it expects to receive. * - if `option_static_remotekey` applies to the commitment transaction: * - MUST set `my_current_per_commitment_point` to a valid point. * - otherwise: * - MUST set `my_current_per_commitment_point` to its commitment * point for the last signed commitment it received from its * channel peer (i.e. the commitment_point corresponding to the * commitment transaction the sender would use to unilaterally * close). * - if `next_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 (peer->channel->option_static_remotekey) { msg = towire_channel_reestablish (NULL, &peer->channel_id, peer->next_index[LOCAL], peer->revocations_received, last_remote_per_commit_secret, /* Can send any (valid) point here */ &peer->remote_per_commit #if EXPERIMENTAL_FEATURES , send_tlvs #endif ); } else { msg = towire_channel_reestablish (NULL, &peer->channel_id, peer->next_index[LOCAL], peer->revocations_received, last_remote_per_commit_secret, &my_current_per_commitment_point #if EXPERIMENTAL_FEATURES , send_tlvs #endif ); } sync_crypto_write(peer->pps, take(msg)); peer_billboard(false, "Sent reestablish, waiting for theirs"); bool soft_error = peer->funding_locked[REMOTE] || peer->funding_locked[LOCAL]; /* If they sent reestablish, we analyze it for courtesy, but also * in case *they* are ahead of us! */ if (reestablish_only) { msg = reestablish_only; goto got_reestablish; } /* 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->pps); } while (channeld_handle_custommsg(msg) || handle_peer_gossip_or_error(peer->pps, &peer->channel_id, soft_error, msg) || capture_premature_msg(&premature_msgs, msg)); got_reestablish: #if EXPERIMENTAL_FEATURES recv_tlvs = tlv_channel_reestablish_tlvs_new(tmpctx); #endif if (!fromwire_channel_reestablish(msg, &channel_id, &next_commitment_number, &next_revocation_number, &last_local_per_commitment_secret, &remote_current_per_commitment_point #if EXPERIMENTAL_FEATURES , recv_tlvs #endif )) { peer_failed_warn(peer->pps, &peer->channel_id, "bad reestablish msg: %s %s", peer_wire_name(fromwire_peektype(msg)), tal_hex(msg, msg)); } if (!channel_id_eq(&channel_id, &peer->channel_id)) { peer_failed_err(peer->pps, &channel_id, "bad reestablish msg for unknown channel %s: %s", type_to_string(tmpctx, struct channel_id, &channel_id), tal_hex(msg, msg)); } status_debug("Got reestablish commit=%"PRIu64" revoke=%"PRIu64, next_commitment_number, next_revocation_number); /* BOLT #2: * * - if `next_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_commitment_number == 1) { u8 *msg; status_debug("Retransmitting funding_locked for channel %s", type_to_string(tmpctx, struct channel_id, &peer->channel_id)); /* 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->pps, 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_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`. * - if it has previously sent a `commitment_signed` that needs to be * retransmitted: * - MUST retransmit `revoke_and_ack` and `commitment_signed` in the * same relative order as initially transmitted. * - otherwise: * - if `next_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_revocation_number` is not equal to 0: * - SHOULD fail the channel. */ if (next_revocation_number == peer->next_index[LOCAL] - 2) { /* Don't try to retransmit revocation index -1! */ if (peer->next_index[LOCAL] < 2) { peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish revocation_number: %" PRIu64, next_revocation_number); } retransmit_revoke_and_ack = true; } else if (next_revocation_number < peer->next_index[LOCAL] - 1) { peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish revocation_number: %"PRIu64 " vs %"PRIu64, next_revocation_number, peer->next_index[LOCAL]); } else if (next_revocation_number > peer->next_index[LOCAL] - 1) { if (!check_extra_fields) /* They don't support option_data_loss_protect or * option_static_remotekey, we fail it due to * unexpected number */ peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish revocation_number: %"PRIu64 " vs %"PRIu64, next_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_revocation_number, &last_local_per_commitment_secret, peer->channel->option_static_remotekey ? NULL : &remote_current_per_commitment_point); } else retransmit_revoke_and_ack = false; /* BOLT #2: * * - if `next_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_commitment_number == peer->next_index[REMOTE] - 1) { /* We completed opening, we don't re-transmit that one! */ if (next_commitment_number == 0) peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish commitment_number: %" PRIu64, next_commitment_number); retransmit_commitment_signed = true; /* BOLT #2: * * - otherwise: * - if `next_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_commitment_number != peer->next_index[REMOTE]) peer_failed_err(peer->pps, &peer->channel_id, "bad reestablish commitment_number: %"PRIu64 " vs %"PRIu64, next_commitment_number, peer->next_index[REMOTE]); else retransmit_commitment_signed = false; /* After we checked basic sanity, we check dataloss fields if any */ if (check_extra_fields) check_current_dataloss_fields(peer, next_revocation_number, next_commitment_number, &last_local_per_commitment_secret, peer->channel->option_static_remotekey ? NULL : &remote_current_per_commitment_point); /* BOLT #2: * - if it has previously sent a `commitment_signed` that needs to be * retransmitted: * - MUST retransmit `revoke_and_ack` and `commitment_signed` in the * same relative order as initially transmitted. */ 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); #if EXPERIMENTAL_FEATURES if (recv_tlvs->desired_type) status_debug("They sent desired_type [%s]", fmt_featurebits(tmpctx, recv_tlvs->desired_type->features)); if (recv_tlvs->current_type) status_debug("They sent current_type [%s]", fmt_featurebits(tmpctx, recv_tlvs->current_type->features)); for (size_t i = 0; i < tal_count(recv_tlvs->upgradable); i++) { status_debug("They offered upgrade to [%s]", fmt_featurebits(tmpctx, recv_tlvs->upgradable[i]->features)); } /* BOLT-upgrade_protocol #2: * * A node receiving `channel_reestablish`: * - if it has to retransmit `commitment_signed` or `revoke_and_ack`: * - MUST consider the channel feature change failed. */ if (retransmit_commitment_signed || retransmit_revoke_and_ack) { status_debug("No upgrade: we retransmitted"); /* BOLT-upgrade_protocol #2: * * - if `next_to_send` is missing, or not equal to the * `next_commitment_number` it sent: * - MUST consider the channel feature change failed. */ } else if (!recv_tlvs->next_to_send) { status_debug("No upgrade: no next_to_send received"); } else if (*recv_tlvs->next_to_send != peer->next_index[LOCAL]) { status_debug("No upgrade: they're retransmitting"); /* BOLT-upgrade_protocol #2: * * - if updates are pending on either sides' commitment transaction: * - MUST consider the channel feature change failed. */ /* Note that we can have HTLCs we *want* to add or remove * but haven't yet: thats OK! */ } else if (pending_updates(peer->channel, LOCAL, true) || pending_updates(peer->channel, REMOTE, true)) { status_debug("No upgrade: pending changes"); } else { const struct tlv_channel_reestablish_tlvs *initr, *ninitr; const struct channel_type *type; if (peer->channel->opener == LOCAL) { initr = send_tlvs; ninitr = recv_tlvs; } else { initr = recv_tlvs; ninitr = send_tlvs; } /* BOLT-upgrade_protocol #2: * * - if `desired_type` matches `current_type` or any * `upgradable` `upgrades`: * - MUST consider the channel type to be `desired_type`. * - otherwise: * - MUST consider the channel feature change failed. * - if there is a `current_type` field: * - MUST consider the channel type to be `current_type`. */ /* Note: returns NULL on missing fields, aka NULL */ if (match_type(initr->desired_type, ninitr->current_type, ninitr->upgradable)) type = initr->desired_type; else if (ninitr->current_type) type = ninitr->current_type; else type = NULL; if (type) set_channel_type(peer->channel, type); } tal_free(send_tlvs); #endif /* EXPERIMENTAL_FEATURES */ /* Now stop, we've been polite long enough. */ if (reestablish_only) { /* If we were successfully closing, we still go to closingd. */ if (shutdown_complete(peer)) { send_shutdown_complete(peer); daemon_shutdown(); exit(0); } peer_failed_err(peer->pps, &peer->channel_id, "Channel is already closed"); } /* 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); } /* We allow peer to send us tx-sigs, until funding locked received */ peer->tx_sigs_allowed = true; peer_billboard(true, "Reconnected, and reestablished."); /* BOLT #2: * - upon reconnection: *... * - 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. */ /* LND doesn't wait. */ for (size_t i = 0; i < tal_count(premature_msgs); i++) peer_in(peer, premature_msgs[i]); tal_free(premature_msgs); } /* ignores the funding_depth unless depth >= minimum_depth * (except to update billboard, and set peer->depth_togo). */ static void handle_funding_depth(struct peer *peer, const u8 *msg) { u32 depth; struct short_channel_id *scid; if (!fromwire_channeld_funding_depth(tmpctx, msg, &scid, &depth)) master_badmsg(WIRE_CHANNELD_FUNDING_DEPTH, msg); /* Too late, we're shutting down! */ if (peer->shutdown_sent[LOCAL]) return; if (depth < peer->channel->minimum_depth) { peer->depth_togo = peer->channel->minimum_depth - depth; } else { peer->depth_togo = 0; assert(scid); peer->short_channel_ids[LOCAL] = *scid; if (!peer->funding_locked[LOCAL]) { status_debug("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->pps, 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(ROUTING_INFO_SIZE)]; enum channel_add_err e; const u8 *failwiremsg; const char *failstr; struct amount_sat htlc_fee; struct pubkey *blinding; if (!peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) status_failed(STATUS_FAIL_MASTER_IO, "funding not locked for offer_htlc"); if (!fromwire_channeld_offer_htlc(tmpctx, inmsg, &amount, &cltv_expiry, &payment_hash, onion_routing_packet, &blinding)) master_badmsg(WIRE_CHANNELD_OFFER_HTLC, inmsg); #if EXPERIMENTAL_FEATURES struct tlv_update_add_tlvs *tlvs; if (blinding) { tlvs = tlv_update_add_tlvs_new(tmpctx); tlvs->blinding = tal_dup(tlvs, struct pubkey, blinding); } else tlvs = NULL; #endif e = channel_add_htlc(peer->channel, LOCAL, peer->htlc_id, amount, cltv_expiry, &payment_hash, onion_routing_packet, take(blinding), NULL, &htlc_fee); status_debug("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 #if EXPERIMENTAL_FEATURES , tlvs #endif ); sync_crypto_write(peer->pps, take(msg)); start_commit_timer(peer); /* Tell the master. */ msg = towire_channeld_offer_htlc_reply(NULL, peer->htlc_id, 0, ""); wire_sync_write(MASTER_FD, take(msg)); peer->htlc_id++; return; case CHANNEL_ERR_INVALID_EXPIRY: failwiremsg = towire_incorrect_cltv_expiry(inmsg, cltv_expiry, get_local_channel_update(tmpctx, peer)); failstr = 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); case CHANNEL_ERR_MAX_HTLC_VALUE_EXCEEDED: failwiremsg = towire_required_node_feature_missing(inmsg); failstr = "Mini mode: maximum value exceeded"; goto failed; /* FIXME: Fuzz the boundaries a bit to avoid probing? */ case CHANNEL_ERR_CHANNEL_CAPACITY_EXCEEDED: failwiremsg = towire_temporary_channel_failure(inmsg, get_local_channel_update(inmsg, peer)); failstr = tal_fmt(inmsg, "Capacity exceeded - HTLC fee: %s", fmt_amount_sat(inmsg, htlc_fee)); goto failed; case CHANNEL_ERR_HTLC_BELOW_MINIMUM: failwiremsg = towire_amount_below_minimum(inmsg, amount, get_local_channel_update(inmsg, peer)); failstr = 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: failwiremsg = towire_temporary_channel_failure(inmsg, get_local_channel_update(inmsg, peer)); failstr = "Too many HTLCs"; goto failed; } /* Shouldn't return anything else! */ abort(); failed: msg = towire_channeld_offer_htlc_reply(NULL, 0, failwiremsg, failstr); wire_sync_write(MASTER_FD, take(msg)); } static void handle_feerates(struct peer *peer, const u8 *inmsg) { u32 feerate; if (!fromwire_channeld_feerates(inmsg, &feerate, &peer->feerate_min, &peer->feerate_max, &peer->feerate_penalty)) master_badmsg(WIRE_CHANNELD_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->opener == LOCAL) { peer->desired_feerate = feerate; /* Don't do this for the first feerate, wait until something else * happens. LND seems to get upset in some cases otherwise: * see https://github.com/ElementsProject/lightning/issues/3596 */ if (peer->next_index[LOCAL] != 1 || peer->next_index[REMOTE] != 1) 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_blockheight(struct peer *peer, const u8 *inmsg) { u32 blockheight; if (!fromwire_channeld_blockheight(inmsg, &blockheight)) master_badmsg(WIRE_CHANNELD_BLOCKHEIGHT, inmsg); /* Save it, so we know */ peer->our_blockheight = blockheight; if (peer->channel->opener == LOCAL) start_commit_timer(peer); else { u32 peer_height = get_blockheight(peer->channel->blockheight_states, peer->channel->opener, REMOTE); /* BOLT- #2: * The node _not responsible_ for initiating the channel: * ... * - if last received `blockheight` is > 1008 behind * currently known blockheight: * - SHOULD fail he channel */ assert(peer_height + 1008 > peer_height); if (peer_height + 1008 < blockheight) peer_failed_err(peer->pps, &peer->channel_id, "Peer is too far behind, terminating" " leased channel. Our current" " %u, theirs %u", blockheight, peer_height); /* We're behind them... what do. It's possible they're lying, * but if we're in a lease this is actually in our favor so * we log it but otherwise continue on unchanged */ if (peer_height > blockheight && peer_height > blockheight + 100) status_unusual("Peer reporting we've fallen %u" " blocks behind. Our height %u," " their height %u", peer_height - blockheight, blockheight, peer_height); } } static void handle_specific_feerates(struct peer *peer, const u8 *inmsg) { u32 base_old = peer->fee_base; u32 per_satoshi_old = peer->fee_per_satoshi; if (!fromwire_channeld_specific_feerates(inmsg, &peer->fee_base, &peer->fee_per_satoshi)) master_badmsg(WIRE_CHANNELD_SPECIFIC_FEERATES, inmsg); /* only send channel updates if values actually changed */ if (peer->fee_base != base_old || peer->fee_per_satoshi != per_satoshi_old) send_channel_update(peer, 0); } static void handle_preimage(struct peer *peer, const u8 *inmsg) { struct fulfilled_htlc fulfilled_htlc; struct htlc *h; if (!fromwire_channeld_fulfill_htlc(inmsg, &fulfilled_htlc)) master_badmsg(WIRE_CHANNELD_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_channeld_fail_htlc(inmsg, inmsg, &failed_htlc)) master_badmsg(WIRE_CHANNELD_FAIL_HTLC, inmsg); e = channel_fail_htlc(peer->channel, REMOTE, failed_htlc->id, &h); switch (e) { case CHANNEL_ERR_REMOVE_OK: h->failed = tal_steal(h, failed_htlc); 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) { u8 *local_shutdown_script; if (!fromwire_channeld_send_shutdown(peer, inmsg, &local_shutdown_script, &peer->shutdown_wrong_funding)) master_badmsg(WIRE_CHANNELD_SEND_SHUTDOWN, inmsg); tal_free(peer->final_scriptpubkey); peer->final_scriptpubkey = local_shutdown_script; /* We can't send this until commit (if any) is done, so start timer. */ peer->send_shutdown = true; start_commit_timer(peer); } static void handle_send_error(struct peer *peer, const u8 *msg) { char *reason; if (!fromwire_channeld_send_error(msg, msg, &reason)) master_badmsg(WIRE_CHANNELD_SEND_ERROR, msg); status_debug("Send error reason: %s", reason); sync_crypto_write(peer->pps, take(towire_errorfmt(NULL, &peer->channel_id, "%s", reason))); wire_sync_write(MASTER_FD, take(towire_channeld_send_error_reply(NULL))); } #if DEVELOPER static void handle_dev_reenable_commit(struct peer *peer) { dev_suppress_commit = false; start_commit_timer(peer); status_debug("dev_reenable_commit"); wire_sync_write(MASTER_FD, take(towire_channeld_dev_reenable_commit_reply(NULL))); } static void handle_dev_memleak(struct peer *peer, const u8 *msg) { struct htable *memtable; bool found_leak; memtable = memleak_find_allocations(tmpctx, msg, msg); /* Now delete peer and things it has pointers to. */ memleak_remove_region(memtable, peer, tal_bytelen(peer)); found_leak = dump_memleak(memtable); wire_sync_write(MASTER_FD, take(towire_channeld_dev_memleak_reply(NULL, found_leak))); } #if EXPERIMENTAL_FEATURES static void handle_dev_quiesce(struct peer *peer, const u8 *msg) { if (!fromwire_channeld_dev_quiesce(msg)) master_badmsg(WIRE_CHANNELD_DEV_QUIESCE, msg); /* Don't do this twice. */ if (peer->stfu) status_failed(STATUS_FAIL_MASTER_IO, "dev_quiesce already"); peer->stfu = true; peer->stfu_initiator = LOCAL; maybe_send_stfu(peer); } #endif /* EXPERIMENTAL_FEATURES */ #endif /* DEVELOPER */ /* We were told to send a custommsg to the peer by `lightningd`. All the * verification is done on the side of `lightningd` so we should be good to * just forward it here. */ static void channeld_send_custommsg(struct peer *peer, const u8 *msg) { u8 *inner; if (!fromwire_custommsg_out(tmpctx, msg, &inner)) master_badmsg(WIRE_CUSTOMMSG_OUT, msg); sync_crypto_write(peer->pps, take(inner)); } static void req_in(struct peer *peer, const u8 *msg) { enum channeld_wire t = fromwire_peektype(msg); switch (t) { case WIRE_CHANNELD_FUNDING_DEPTH: handle_funding_depth(peer, msg); return; case WIRE_CHANNELD_OFFER_HTLC: if (handle_master_request_later(peer, msg)) return; handle_offer_htlc(peer, msg); return; case WIRE_CHANNELD_FEERATES: if (handle_master_request_later(peer, msg)) return; handle_feerates(peer, msg); return; case WIRE_CHANNELD_BLOCKHEIGHT: if (handle_master_request_later(peer, msg)) return; handle_blockheight(peer, msg); return; case WIRE_CHANNELD_FULFILL_HTLC: if (handle_master_request_later(peer, msg)) return; handle_preimage(peer, msg); return; case WIRE_CHANNELD_FAIL_HTLC: if (handle_master_request_later(peer, msg)) return; handle_fail(peer, msg); return; case WIRE_CHANNELD_SPECIFIC_FEERATES: if (handle_master_request_later(peer, msg)) return; handle_specific_feerates(peer, msg); return; case WIRE_CHANNELD_SEND_SHUTDOWN: handle_shutdown_cmd(peer, msg); return; case WIRE_CHANNELD_SEND_ERROR: handle_send_error(peer, msg); return; #if DEVELOPER case WIRE_CHANNELD_DEV_REENABLE_COMMIT: handle_dev_reenable_commit(peer); return; case WIRE_CHANNELD_DEV_MEMLEAK: handle_dev_memleak(peer, msg); return; case WIRE_CHANNELD_DEV_QUIESCE: #if EXPERIMENTAL_FEATURES handle_dev_quiesce(peer, msg); return; #endif /* EXPERIMENTAL_FEATURES */ #else case WIRE_CHANNELD_DEV_REENABLE_COMMIT: case WIRE_CHANNELD_DEV_MEMLEAK: case WIRE_CHANNELD_DEV_QUIESCE: #endif /* DEVELOPER */ case WIRE_CHANNELD_INIT: case WIRE_CHANNELD_OFFER_HTLC_REPLY: case WIRE_CHANNELD_SENDING_COMMITSIG: case WIRE_CHANNELD_GOT_COMMITSIG: case WIRE_CHANNELD_GOT_REVOKE: case WIRE_CHANNELD_SENDING_COMMITSIG_REPLY: case WIRE_CHANNELD_GOT_COMMITSIG_REPLY: case WIRE_CHANNELD_GOT_REVOKE_REPLY: case WIRE_CHANNELD_GOT_FUNDING_LOCKED: case WIRE_CHANNELD_GOT_ANNOUNCEMENT: case WIRE_CHANNELD_GOT_SHUTDOWN: case WIRE_CHANNELD_SHUTDOWN_COMPLETE: case WIRE_CHANNELD_DEV_REENABLE_COMMIT_REPLY: case WIRE_CHANNELD_FAIL_FALLEN_BEHIND: case WIRE_CHANNELD_DEV_MEMLEAK_REPLY: case WIRE_CHANNELD_SEND_ERROR_REPLY: case WIRE_CHANNELD_DEV_QUIESCE_REPLY: case WIRE_CHANNELD_UPGRADED: break; } /* Now handle common messages. */ switch ((enum common_wire)t) { case WIRE_CUSTOMMSG_OUT: channeld_send_custommsg(peer, msg); return; /* We send these. */ case WIRE_CUSTOMMSG_IN: break; } master_badmsg(-1, msg); } /* 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 opener; struct existing_htlc **htlcs; bool reconnected; u8 *fwd_msg; const u8 *msg; struct fee_states *fee_states; struct height_states *blockheight_states; u32 minimum_depth, lease_expiry; struct secret last_remote_per_commit_secret; secp256k1_ecdsa_signature *remote_ann_node_sig; secp256k1_ecdsa_signature *remote_ann_bitcoin_sig; bool option_static_remotekey, option_anchor_outputs; struct penalty_base *pbases; u8 *reestablish_only; #if !DEVELOPER bool dev_fail_process_onionpacket; /* Ignored */ #endif assert(!(fcntl(MASTER_FD, F_GETFL) & O_NONBLOCK)); msg = wire_sync_read(tmpctx, MASTER_FD); if (!fromwire_channeld_init(peer, msg, &chainparams, &peer->our_features, &peer->channel_id, &funding_txid, &funding_txout, &funding, &minimum_depth, &peer->our_blockheight, &blockheight_states, &lease_expiry, &conf[LOCAL], &conf[REMOTE], &fee_states, &peer->feerate_min, &peer->feerate_max, &peer->feerate_penalty, &peer->their_commit_sig, &peer->pps, &funding_pubkey[REMOTE], &points[REMOTE], &peer->remote_per_commit, &peer->old_remote_per_commit, &opener, &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, &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, &fwd_msg, &peer->announce_depth_reached, &last_remote_per_commit_secret, &peer->their_features, &peer->remote_upfront_shutdown_script, &remote_ann_node_sig, &remote_ann_bitcoin_sig, &option_static_remotekey, &option_anchor_outputs, &dev_fast_gossip, &dev_fail_process_onionpacket, &pbases, &reestablish_only)) { master_badmsg(WIRE_CHANNELD_INIT, msg); } status_debug("option_static_remotekey = %u, option_anchor_outputs = %u", option_static_remotekey, option_anchor_outputs); /* Keeping an array of pointers is better since it allows us to avoid * extra allocations later. */ peer->pbases = tal_arr(peer, struct penalty_base *, 0); for (size_t i=0; ipbases, tal_dup(peer, struct penalty_base, &pbases[i])); tal_free(pbases); /* stdin == requests, 3 == peer, 4 = gossip, 5 = gossip_store, 6 = HSM */ per_peer_state_set_fds(peer->pps, 3, 4, 5); status_debug("init %s: remote_per_commit = %s, old_remote_per_commit = %s" " next_idx_local = %"PRIu64 " next_idx_remote = %"PRIu64 " revocations_received = %"PRIu64 " feerates %s range %u-%u" " blockheights %s, our current %u", side_to_str(opener), 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, type_to_string(tmpctx, struct fee_states, fee_states), peer->feerate_min, peer->feerate_max, type_to_string(tmpctx, struct height_states, blockheight_states), peer->our_blockheight); status_debug("option_static_remotekey = %u", option_static_remotekey); if (remote_ann_node_sig && remote_ann_bitcoin_sig) { peer->announcement_node_sigs[REMOTE] = *remote_ann_node_sig; peer->announcement_bitcoin_sigs[REMOTE] = *remote_ann_bitcoin_sig; peer->have_sigs[REMOTE] = true; /* Before we store announcement into DB, we have made sure * remote short_channel_id matched the local. Now we initial * it directly! */ peer->short_channel_ids[REMOTE] = peer->short_channel_ids[LOCAL]; tal_free(remote_ann_node_sig); tal_free(remote_ann_bitcoin_sig); } /* 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); peer->channel = new_full_channel(peer, &peer->channel_id, &funding_txid, funding_txout, minimum_depth, take(blockheight_states), lease_expiry, funding, local_msat, take(fee_states), &conf[LOCAL], &conf[REMOTE], &points[LOCAL], &points[REMOTE], &funding_pubkey[LOCAL], &funding_pubkey[REMOTE], option_static_remotekey, option_anchor_outputs, opener); if (!channel_force_htlcs(peer->channel, cast_const2(const struct existing_htlc **, htlcs))) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not restore HTLCs"); /* We don't need these any more, so free them. */ tal_free(htlcs); peer->channel_direction = node_id_idx(&peer->node_ids[LOCAL], &peer->node_ids[REMOTE]); /* Default desired feerate is the feerate we set for them last. */ if (peer->channel->opener == LOCAL) peer->desired_feerate = channel_feerate(peer->channel, REMOTE); /* from now we need keep watch over WIRE_CHANNELD_FUNDING_DEPTH */ peer->depth_togo = minimum_depth; /* OK, now we can process peer messages. */ if (reconnected) peer_reconnect(peer, &last_remote_per_commit_secret, reestablish_only); else assert(!reestablish_only); /* If we have a messages to send, send them immediately */ if (fwd_msg) sync_crypto_write(peer->pps, take(fwd_msg)); /* Reenable channel */ channel_announcement_negotiate(peer); billboard_update(peer); } static void try_read_gossip_store(struct peer *peer) { u8 *msg = gossip_store_next(tmpctx, peer->pps); if (msg) sync_crypto_write(peer->pps, take(msg)); } int main(int argc, char *argv[]) { setup_locale(); int i, nfds; fd_set fds_in, fds_out; struct peer *peer; subdaemon_setup(argc, argv); status_setup_sync(MASTER_FD); 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->shutdown_sent[LOCAL] = false; peer->shutdown_wrong_funding = NULL; peer->last_update_timestamp = 0; /* We actually received it in the previous daemon, but near enough */ peer->last_recv = time_now(); peer->last_empty_commitment = 0; #if EXPERIMENTAL_FEATURES peer->stfu = false; peer->stfu_sent[LOCAL] = peer->stfu_sent[REMOTE] = false; peer->update_queue = msg_queue_new(peer); #endif /* 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])); } /* Prepare the ecdh() function for use */ ecdh_hsmd_setup(HSM_FD, status_failed); /* Read init_channel message sync. */ init_channel(peer); FD_ZERO(&fds_in); FD_SET(MASTER_FD, &fds_in); FD_SET(peer->pps->peer_fd, &fds_in); FD_SET(peer->pps->gossip_fd, &fds_in); FD_ZERO(&fds_out); FD_SET(peer->pps->peer_fd, &fds_out); nfds = peer->pps->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 timerel trel; 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_debug("Now dealing with deferred %s", channeld_wire_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; } if (timer_earliest(&peer->timers, &first)) { timeout = timespec_to_timeval( timemono_between(first, now).ts); tptr = &timeout; } else if (time_to_next_gossip(peer->pps, &trel)) { timeout = timerel_to_timeval(trel); 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->pps->peer_fd, &rfds)) { /* This could take forever, but who cares? */ msg = sync_crypto_read(tmpctx, peer->pps); peer_in(peer, msg); } else if (FD_ISSET(peer->pps->gossip_fd, &rfds)) { msg = wire_sync_read(tmpctx, peer->pps->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->pps, take(msg)); } else /* Lowest priority: stream from store. */ try_read_gossip_store(peer); } /* We only exit when shutdown is complete. */ assert(shutdown_complete(peer)); send_shutdown_complete(peer); daemon_shutdown(); return 0; }