/* Main channel operation daemon: runs from funding_locked to shutdown_complete. * * We're fairly synchronous: our main loop looks for gossip, master or * peer requests and services them synchronously. * * The exceptions are: * 1. When we've asked the master something: in that case, we queue * non-response packets for later processing while we await the reply. * 2. We queue and send non-blocking responses to peers: if both peers were * reading and writing synchronously we could deadlock if we hit buffer * limits, unlikely as that is. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* stdin == requests, 3 == peer, 4 = gossip, 5 = HSM */ #define MASTER_FD STDIN_FILENO #define PEER_FD 3 #define GOSSIP_FD 4 #define HSM_FD 5 struct commit_sigs { struct peer *peer; secp256k1_ecdsa_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; }; struct peer { struct crypto_state cs; struct channel_config conf[NUM_SIDES]; bool funding_locked[NUM_SIDES]; u64 next_index[NUM_SIDES]; /* Tolerable amounts for feerate (only relevant for fundee). */ u32 feerate_min, feerate_max; /* 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. */ secp256k1_ecdsa_signature their_commit_sig; /* Secret keys and basepoint secrets. */ struct secrets our_secrets; /* Our shaseed for generating per-commitment-secrets. */ struct sha256 shaseed; /* BOLT #2: * * A sending node MUST set `id` to 0 for the first HTLC it offers, and * increase the value by 1 for each successive offer. */ u64 htlc_id; struct bitcoin_blkid chain_hash; struct channel_id channel_id; struct channel *channel; /* Pending msgs to send (not encrypted) */ struct msg_queue peer_out; /* Current msg to send, and offset (encrypted) */ const u8 *peer_outmsg; size_t peer_outoff; /* Messages from master / gossipd: we queue them since we * might be waiting for a specific reply. */ struct msg_queue from_master, from_gossipd; struct timers timers; struct oneshot *commit_timer; u64 commit_timer_attempts; u32 commit_msec; /* Don't accept a pong we didn't ping for. */ size_t num_pings_outstanding; /* The feerate we want. */ u32 desired_feerate; /* Announcement related information */ struct pubkey node_ids[NUM_SIDES]; struct short_channel_id short_channel_ids[NUM_SIDES]; secp256k1_ecdsa_signature announcement_node_sigs[NUM_SIDES]; secp256k1_ecdsa_signature announcement_bitcoin_sigs[NUM_SIDES]; bool have_sigs[NUM_SIDES]; /* Which direction of the channel do we control? */ u16 channel_direction; /* CLTV delta to announce to peers */ u16 cltv_delta; u32 fee_base; u32 fee_per_satoshi; /* We save calculated commit sigs while waiting for master approval */ struct commit_sigs *next_commit_sigs; /* The scriptpubkey to use for shutting down. */ u8 *final_scriptpubkey; /* If master told us to shut down */ bool send_shutdown; /* Has shutdown been sent by each side? */ bool shutdown_sent[NUM_SIDES]; /* Information used for reestablishment. */ bool last_was_revoke; struct changed_htlc *last_sent_commit; u64 revocations_received; u8 channel_flags; bool announce_depth_reached; /* Where we got up to in gossip broadcasts. */ u64 gossip_index; /* Make sure timestamps move forward. */ u32 last_update_timestamp; }; static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer); static void start_commit_timer(struct peer *peer); static void billboard_update(const struct peer *peer) { const char *funding_status, *announce_status, *shutdown_status; if (peer->funding_locked[LOCAL] && peer->funding_locked[REMOTE]) funding_status = "Funding transaction locked."; else if (!peer->funding_locked[LOCAL] && !peer->funding_locked[REMOTE]) /* FIXME: Say how many blocks to go! */ funding_status = "Funding needs more confirmations."; else if (peer->funding_locked[LOCAL] && !peer->funding_locked[REMOTE]) funding_status = "We've confirmed funding, they haven't yet."; else if (!peer->funding_locked[LOCAL] && peer->funding_locked[REMOTE]) funding_status = "They've confirmed funding, we haven't yet."; if (peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) announce_status = " Channel announced."; else if (peer->have_sigs[LOCAL] && !peer->have_sigs[REMOTE]) announce_status = " Waiting for their announcement signatures."; else if (!peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) announce_status = " They need our announcement signatures."; else if (!peer->have_sigs[LOCAL] && !peer->have_sigs[REMOTE]) announce_status = ""; if (!peer->shutdown_sent[LOCAL] && !peer->shutdown_sent[REMOTE]) shutdown_status = ""; else if (!peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE]) shutdown_status = " We've send shutdown, waiting for theirs"; else if (peer->shutdown_sent[LOCAL] && !peer->shutdown_sent[REMOTE]) shutdown_status = " They've sent shutdown, waiting for ours"; else if (peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE]) { size_t num_htlcs = num_channel_htlcs(peer->channel); if (num_htlcs) shutdown_status = tal_fmt(tmpctx, " Shutdown messages exchanged," " waiting for %zu HTLCs to complete.", num_htlcs); else shutdown_status = tal_fmt(tmpctx, " Shutdown messages exchanged."); } peer_billboard(false, "%s%s%s", funding_status, announce_status, shutdown_status); } /* Returns a pointer to the new end */ static void *tal_arr_append_(void **p, size_t size) { size_t n = tal_len(*p) / size; tal_resize_(p, size, n+1, false); return (char *)(*p) + n * size; } #define tal_arr_append(p) tal_arr_append_((void **)(p), sizeof(**(p))) static void do_peer_write(struct peer *peer) { int r; size_t len = tal_len(peer->peer_outmsg); r = write(PEER_FD, peer->peer_outmsg + peer->peer_outoff, len - peer->peer_outoff); if (r < 0) peer_failed_connection_lost(); peer->peer_outoff += r; if (peer->peer_outoff == len) peer->peer_outmsg = tal_free(peer->peer_outmsg); } static bool peer_write_pending(struct peer *peer) { const u8 *msg; if (peer->peer_outmsg) return true; msg = msg_dequeue(&peer->peer_out); if (!msg) return false; status_io(LOG_IO_OUT, msg); peer->peer_outmsg = cryptomsg_encrypt_msg(peer, &peer->cs, take(msg)); peer->peer_outoff = 0; return true; } /* Synchronous flush of all pending packets. */ static void flush_peer_out(struct peer *peer) { while (peer_write_pending(peer)) do_peer_write(peer); } static void enqueue_peer_msg(struct peer *peer, const u8 *msg TAKES) { #if DEVELOPER enum dev_disconnect d = dev_disconnect(fromwire_peektype(msg)); /* We want to effect this exact packet, so flush any pending. */ if (d != DEV_DISCONNECT_NORMAL) flush_peer_out(peer); switch (d) { case DEV_DISCONNECT_BEFORE: /* Fail immediately. */ dev_sabotage_fd(PEER_FD); msg_enqueue(&peer->peer_out, msg); flush_peer_out(peer); /* Should not return */ abort(); case DEV_DISCONNECT_DROPPKT: tal_free(msg); /* Fail next time we try to do something. */ dev_sabotage_fd(PEER_FD); return; case DEV_DISCONNECT_AFTER: msg_enqueue(&peer->peer_out, msg); flush_peer_out(peer); dev_sabotage_fd(PEER_FD); return; case DEV_DISCONNECT_BLACKHOLE: msg_enqueue(&peer->peer_out, msg); dev_blackhole_fd(PEER_FD); return; case DEV_DISCONNECT_NORMAL: break; } #endif msg_enqueue(&peer->peer_out, msg); } static void gossip_in(struct peer *peer, const u8 *msg) { u8 *gossip; u64 gossip_index; if (!fromwire_gossip_send_gossip(msg, msg, &gossip_index, &gossip)) status_failed(STATUS_FAIL_GOSSIP_IO, "Got bad message from gossipd: %s", tal_hex(msg, msg)); /* Zero is a special index meaning this is unindexed gossip. */ if (gossip_index != 0) peer->gossip_index = gossip_index; if (is_msg_for_gossipd(gossip)) enqueue_peer_msg(peer, gossip); else if (fromwire_peektype(gossip) == WIRE_ERROR) { struct channel_id channel_id; char *what = sanitize_error(msg, msg, &channel_id); peer_failed(&peer->cs, peer->gossip_index, &channel_id, "gossipd said: %s", what); } else status_failed(STATUS_FAIL_GOSSIP_IO, "Got bad message type %s from gossipd: %s", wire_type_name(fromwire_peektype(gossip)), tal_hex(msg, msg)); } /* Send a temporary `channel_announcement` and `channel_update`. These * are unsigned and mainly used to tell gossip about the channel * before we have reached the `announcement_depth`, not being signed * means they will not be relayed, but we can already rely on them for * our own outgoing payments */ static void send_temporary_announcement(struct peer *peer) { u8 *msg; /* If we are supposed to send a real announcement, don't do a * dummy one here, hence the check for announce_depth. */ if (peer->announce_depth_reached || !peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) return; msg = towire_gossip_local_add_channel( NULL, &peer->short_channel_ids[LOCAL], &peer->chain_hash, &peer->node_ids[REMOTE], peer->cltv_delta, peer->conf[REMOTE].htlc_minimum_msat, peer->fee_base, peer->fee_per_satoshi); wire_sync_write(GOSSIP_FD, take(msg)); } 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; u8 *msg, *ca, *req; /* BOLT #7: * * If sent, `announcement_signatures` messages MUST NOT be sent until * `funding_locked` has been sent and the funding transaction has * at least 6 confirmations. */ /* Actually defer a bit further until both ends have signaled */ if (!peer->announce_depth_reached || !peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) return; status_trace("Exchanging announcement signatures."); ca = create_channel_announcement(tmpctx, peer); req = towire_hsm_cannouncement_sig_req( tmpctx, &peer->channel->funding_pubkey[LOCAL], ca); if (!wire_sync_write(HSM_FD, req)) status_failed(STATUS_FAIL_HSM_IO, "Writing cannouncement_sig_req: %s", strerror(errno)); msg = wire_sync_read(tmpctx, HSM_FD); if (!msg || !fromwire_hsm_cannouncement_sig_reply(msg, &peer->announcement_node_sigs[LOCAL])) status_failed(STATUS_FAIL_HSM_IO, "Reading cannouncement_sig_resp: %s", strerror(errno)); /* Double-check that HSM gave a valid signature. */ sha256_double(&hash, ca + offset, tal_len(ca) - offset); if (!check_signed_hash(&hash, &peer->announcement_node_sigs[LOCAL], &peer->node_ids[LOCAL])) { /* It's ok to fail here, the channel announcement is * unique, unlike the channel update which may have * been replaced in the meantime. */ status_failed(STATUS_FAIL_HSM_IO, "HSM returned an invalid signature"); } /* TODO(cdecker) Move this to the HSM once we store the * funding_privkey there */ sign_hash(&peer->our_secrets.funding_privkey, &hash, &peer->announcement_bitcoin_sigs[LOCAL]); peer->have_sigs[LOCAL] = true; billboard_update(peer); msg = towire_announcement_signatures( NULL, &peer->channel_id, &peer->short_channel_ids[LOCAL], &peer->announcement_node_sigs[LOCAL], &peer->announcement_bitcoin_sigs[LOCAL]); enqueue_peer_msg(peer, take(msg)); } static u8 *create_channel_update(const tal_t *ctx, struct peer *peer, bool disabled) { u32 timestamp = time_now().ts.tv_sec; u16 flags; u8 *cupdate, *msg; /* Identical timestamps will be ignored. */ if (timestamp <= peer->last_update_timestamp) timestamp = peer->last_update_timestamp + 1; peer->last_update_timestamp = timestamp; /* Set the signature to empty so that valgrind doesn't complain */ secp256k1_ecdsa_signature *sig = talz(tmpctx, secp256k1_ecdsa_signature); flags = peer->channel_direction | (disabled << 1); cupdate = towire_channel_update( tmpctx, sig, &peer->chain_hash, &peer->short_channel_ids[LOCAL], timestamp, flags, peer->cltv_delta, peer->conf[REMOTE].htlc_minimum_msat, peer->fee_base, peer->fee_per_satoshi); msg = towire_hsm_cupdate_sig_req(tmpctx, cupdate); if (!wire_sync_write(HSM_FD, msg)) status_failed(STATUS_FAIL_HSM_IO, "Writing cupdate_sig_req: %s", strerror(errno)); msg = wire_sync_read(tmpctx, HSM_FD); if (!msg || !fromwire_hsm_cupdate_sig_reply(ctx, msg, &cupdate)) status_failed(STATUS_FAIL_HSM_IO, "Reading cupdate_sig_req: %s", strerror(errno)); return cupdate; } /* Tentatively create a channel_announcement, possibly with invalid * signatures. The signatures need to be collected first, by asking * the HSM and by exchanging announcement_signature messages. */ static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer) { int first, second; u8 *cannounce, *features = tal_arr(ctx, u8, 0); if (peer->channel_direction == 0) { first = LOCAL; second = REMOTE; } else { first = REMOTE; second = LOCAL; } cannounce = towire_channel_announcement( ctx, &peer->announcement_node_sigs[first], &peer->announcement_node_sigs[second], &peer->announcement_bitcoin_sigs[first], &peer->announcement_bitcoin_sigs[second], features, &peer->chain_hash, &peer->short_channel_ids[LOCAL], &peer->node_ids[first], &peer->node_ids[second], &peer->channel->funding_pubkey[first], &peer->channel->funding_pubkey[second]); tal_free(features); return cannounce; } static void handle_peer_funding_locked(struct peer *peer, const u8 *msg) { struct channel_id chanid; /* BOLT #2: * * On reconnection, a node MUST ignore a redundant `funding_locked` if * it receives one. */ if (peer->funding_locked[REMOTE]) return; peer->old_remote_per_commit = peer->remote_per_commit; if (!fromwire_funding_locked(msg, &chanid, &peer->remote_per_commit)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad funding_locked %s", tal_hex(msg, msg)); if (!structeq(&chanid, &peer->channel_id)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Wrong channel id in %s (expected %s)", tal_hex(tmpctx, msg), type_to_string(msg, struct channel_id, &peer->channel_id)); peer->funding_locked[REMOTE] = true; wire_sync_write(MASTER_FD, take(towire_channel_got_funding_locked(NULL, &peer->remote_per_commit))); if (peer->funding_locked[LOCAL]) { wire_sync_write(MASTER_FD, take(towire_channel_normal_operation(NULL))); } billboard_update(peer); /* Send temporary or final announcements */ send_temporary_announcement(peer); send_announcement_signatures(peer); } /* 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 (!structeq(&peer->short_channel_ids[LOCAL], &peer->short_channel_ids[REMOTE])) peer_failed(&peer->cs, peer->gossip_index, &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, *cupdate; check_short_ids_match(peer); cannounce = create_channel_announcement(tmpctx, peer); cupdate = create_channel_update(tmpctx, peer, false); wire_sync_write(GOSSIP_FD, cannounce); wire_sync_write(GOSSIP_FD, cupdate); } static void handle_peer_announcement_signatures(struct peer *peer, const u8 *msg) { struct channel_id chanid; if (!fromwire_announcement_signatures(msg, &chanid, &peer->short_channel_ids[REMOTE], &peer->announcement_node_sigs[REMOTE], &peer->announcement_bitcoin_sigs[REMOTE])) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad announcement_signatures %s", tal_hex(msg, msg)); /* Make sure we agree on the channel ids */ if (!structeq(&chanid, &peer->channel_id)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Wrong channel_id: expected %s, got %s", type_to_string(tmpctx, struct channel_id, &peer->channel_id), type_to_string(tmpctx, struct channel_id, &chanid)); } peer->have_sigs[REMOTE] = true; billboard_update(peer); /* We have the remote sigs, do we have the local ones as well? */ if (peer->funding_locked[LOCAL] && peer->have_sigs[LOCAL]) announce_channel(peer); } static bool get_shared_secret(const struct htlc *htlc, struct secret *shared_secret) { struct pubkey ephemeral; struct onionpacket *op; u8 *msg; /* We unwrap the onion now. */ op = parse_onionpacket(tmpctx, htlc->routing, TOTAL_PACKET_SIZE); if (!op) { /* Return an invalid shared secret. */ memset(shared_secret, 0, sizeof(*shared_secret)); return false; } /* Because wire takes struct pubkey. */ ephemeral.pubkey = op->ephemeralkey; msg = towire_hsm_ecdh_req(tmpctx, &ephemeral); if (!wire_sync_write(HSM_FD, msg)) status_failed(STATUS_FAIL_HSM_IO, "Writing ecdh req"); msg = wire_sync_read(tmpctx, HSM_FD); /* Gives all-zero shares_secret if it was invalid. */ if (!msg || !fromwire_hsm_ecdh_resp(msg, shared_secret)) status_failed(STATUS_FAIL_HSM_IO, "Reading ecdh response"); return !memeqzero(shared_secret, sizeof(*shared_secret)); } static void handle_peer_add_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; u64 amount_msat; u32 cltv_expiry; struct sha256 payment_hash; u8 onion_routing_packet[TOTAL_PACKET_SIZE]; enum channel_add_err add_err; struct htlc *htlc; if (!fromwire_update_add_htlc(msg, &channel_id, &id, &amount_msat, &payment_hash, &cltv_expiry, onion_routing_packet)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad peer_add_htlc %s", tal_hex(msg, msg)); add_err = channel_add_htlc(peer->channel, REMOTE, id, amount_msat, cltv_expiry, &payment_hash, onion_routing_packet, &htlc); if (add_err != CHANNEL_ERR_ADD_OK) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad peer_add_htlc: %s", channel_add_err_name(add_err)); /* If this is wrong, we don't complain yet; when it's confirmed we'll * send it to the master which handles all HTLC failures. */ htlc->shared_secret = tal(htlc, struct secret); get_shared_secret(htlc, htlc->shared_secret); } static void handle_peer_feechange(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u32 feerate; if (!fromwire_update_fee(msg, &channel_id, &feerate)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fee %s", tal_hex(msg, msg)); } /* BOLT #2: * * A receiving node MUST fail the channel if the sender is not * responsible for paying the bitcoin fee. */ if (peer->channel->funder != REMOTE) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "update_fee from non-funder?"); status_trace("update_fee %u, range %u-%u", feerate, peer->feerate_min, peer->feerate_max); /* BOLT #2: * * A receiving node SHOULD fail the channel if the `update_fee` is too * low for timely processing, or unreasonably large. */ if (feerate < peer->feerate_min || feerate > peer->feerate_max) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "update_fee %u outside range %u-%u", feerate, peer->feerate_min, peer->feerate_max); /* BOLT #2: * * A receiving node SHOULD fail the channel if the sender cannot * afford the new fee rate on the receiving node's current commitment * transaction, but it MAY delay this check until the `update_fee` is * committed. */ if (!channel_update_feerate(peer->channel, feerate)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "update_fee %u unaffordable", feerate); status_trace("peer updated fee to %u", feerate); } static struct changed_htlc *changed_htlc_arr(const tal_t *ctx, const struct htlc **changed_htlcs) { struct changed_htlc *changed; size_t i; changed = tal_arr(ctx, struct changed_htlc, tal_count(changed_htlcs)); for (i = 0; i < tal_count(changed_htlcs); i++) { changed[i].id = changed_htlcs[i]->id; changed[i].newstate = changed_htlcs[i]->state; } return changed; } static u8 *sending_commitsig_msg(const tal_t *ctx, u64 remote_commit_index, u32 remote_feerate, const struct htlc **changed_htlcs, const secp256k1_ecdsa_signature *commit_sig, const secp256k1_ecdsa_signature *htlc_sigs) { struct changed_htlc *changed; u8 *msg; /* We tell master what (of our) HTLCs peer will now be * committed to. */ changed = changed_htlc_arr(tmpctx, changed_htlcs); msg = towire_channel_sending_commitsig(ctx, remote_commit_index, remote_feerate, changed, commit_sig, htlc_sigs); return msg; } static bool shutdown_complete(const struct peer *peer) { return peer->shutdown_sent[LOCAL] && peer->shutdown_sent[REMOTE] && num_channel_htlcs(peer->channel) == 0 /* We could be awaiting revoke-and-ack for a feechange */ && peer->revocations_received == peer->next_index[REMOTE] - 1; } /* BOLT #2: * * A node MUST NOT send a `shutdown` if there are updates pending on * the receiving node's commitment transaction. */ /* So we only call this after reestablish or immediately after sending commit */ static void maybe_send_shutdown(struct peer *peer) { u8 *msg; if (!peer->send_shutdown) return; /* Send a disable channel_update so others don't try to route * over us */ msg = create_channel_update(NULL, peer, true); wire_sync_write(GOSSIP_FD, msg); enqueue_peer_msg(peer, take(msg)); msg = towire_shutdown(NULL, &peer->channel_id, peer->final_scriptpubkey); enqueue_peer_msg(peer, take(msg)); peer->send_shutdown = false; peer->shutdown_sent[LOCAL] = true; billboard_update(peer); } /* This queues other traffic from the fd until we get reply. */ static u8 *wait_sync_reply(const tal_t *ctx, const u8 *msg, int replytype, int fd, struct msg_queue *queue, const char *who) { u8 *reply; status_trace("Sending %s %u", who, fromwire_peektype(msg)); if (!wire_sync_write(fd, msg)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync write to %s: %s", who, strerror(errno)); status_trace("... , awaiting %u", replytype); for (;;) { reply = wire_sync_read(ctx, fd); if (!reply) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not set sync read from %s: %s", who, strerror(errno)); if (fromwire_peektype(reply) == replytype) { status_trace("Got it!"); break; } status_trace("Nope, got %u instead", fromwire_peektype(reply)); msg_enqueue(queue, take(reply)); } return reply; } static u8 *master_wait_sync_reply(const tal_t *ctx, struct peer *peer, const u8 *msg, enum channel_wire_type replytype) { return wait_sync_reply(ctx, msg, replytype, MASTER_FD, &peer->from_master, "master"); } static u8 *gossipd_wait_sync_reply(const tal_t *ctx, struct peer *peer, const u8 *msg, enum gossip_wire_type replytype) { return wait_sync_reply(ctx, msg, replytype, GOSSIP_FD, &peer->from_gossipd, "gossipd"); } static struct commit_sigs *calc_commitsigs(const tal_t *ctx, const struct peer *peer, u64 commit_index) { size_t i; struct bitcoin_tx **txs; const u8 **wscripts; const struct htlc **htlc_map; struct pubkey local_htlckey; struct privkey local_htlcsecretkey; struct commit_sigs *commit_sigs = tal(ctx, struct commit_sigs); if (!derive_simple_privkey(&peer->our_secrets.htlc_basepoint_secret, &peer->channel->basepoints[LOCAL].htlc, &peer->remote_per_commit, &local_htlcsecretkey)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving local_htlcsecretkey"); if (!derive_simple_key(&peer->channel->basepoints[LOCAL].htlc, &peer->remote_per_commit, &local_htlckey)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving local_htlckey"); status_trace("Derived key %s from basepoint %s, point %s", type_to_string(tmpctx, struct pubkey, &local_htlckey), type_to_string(tmpctx, struct pubkey, &peer->channel->basepoints[LOCAL].htlc), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit)); txs = channel_txs(tmpctx, &htlc_map, &wscripts, peer->channel, &peer->remote_per_commit, commit_index, REMOTE); sign_tx_input(txs[0], 0, NULL, wscripts[0], &peer->our_secrets.funding_privkey, &peer->channel->funding_pubkey[LOCAL], &commit_sigs->commit_sig); status_trace("Creating commit_sig signature %"PRIu64" %s for tx %s wscript %s key %s", commit_index, type_to_string(tmpctx, secp256k1_ecdsa_signature, &commit_sigs->commit_sig), type_to_string(tmpctx, struct bitcoin_tx, txs[0]), tal_hex(tmpctx, wscripts[0]), type_to_string(tmpctx, struct pubkey, &peer->channel->funding_pubkey[LOCAL])); dump_htlcs(peer->channel, "Sending commit_sig"); /* BOLT #2: * * A node MUST include one `htlc_signature` for every HTLC transaction * corresponding to BIP69 lexicographic ordering of the commitment * transaction. */ commit_sigs->htlc_sigs = tal_arr(commit_sigs, secp256k1_ecdsa_signature, tal_count(txs) - 1); for (i = 0; i < tal_count(commit_sigs->htlc_sigs); i++) { sign_tx_input(txs[1 + i], 0, NULL, wscripts[1 + i], &local_htlcsecretkey, &local_htlckey, &commit_sigs->htlc_sigs[i]); status_trace("Creating HTLC signature %s for tx %s wscript %s key %s", type_to_string(tmpctx, secp256k1_ecdsa_signature, &commit_sigs->htlc_sigs[i]), type_to_string(tmpctx, struct bitcoin_tx, txs[1+i]), tal_hex(tmpctx, wscripts[1+i]), type_to_string(tmpctx, struct pubkey, &local_htlckey)); assert(check_tx_sig(txs[1+i], 0, NULL, wscripts[1+i], &local_htlckey, &commit_sigs->htlc_sigs[i])); } return commit_sigs; } static void send_commit(struct peer *peer) { u8 *msg; const struct htlc **changed_htlcs; #if DEVELOPER /* Hack to suppress all commit sends if dev_disconnect says to */ if (dev_suppress_commit) { peer->commit_timer = NULL; return; } #endif /* FIXME: Document this requirement in BOLT 2! */ /* We can't send two commits in a row. */ if (peer->revocations_received != peer->next_index[REMOTE] - 1) { assert(peer->revocations_received == peer->next_index[REMOTE] - 2); peer->commit_timer_attempts++; /* Only report this in extreme cases */ if (peer->commit_timer_attempts % 100 == 0) status_trace("Can't send commit:" " waiting for revoke_and_ack with %" PRIu64" attempts", peer->commit_timer_attempts); /* Mark this as done and try again. */ peer->commit_timer = NULL; start_commit_timer(peer); return; } /* BOLT #2: * * - if no HTLCs remain in either commitment transaction: * - MUST NOT send any `update` message after a `shutdown`. */ if (peer->shutdown_sent[LOCAL] && !num_channel_htlcs(peer->channel)) { status_trace("Can't send commit: final shutdown phase"); peer->commit_timer = NULL; return; } /* If we wanted to update fees, do it now. */ if (peer->channel->funder == LOCAL && peer->desired_feerate != channel_feerate(peer->channel, REMOTE)) { u8 *msg; u32 feerate, max = approx_max_feerate(peer->channel); feerate = peer->desired_feerate; /* FIXME: We should avoid adding HTLCs until we can meet this * feerate! */ if (feerate > max) feerate = max; if (!channel_update_feerate(peer->channel, feerate)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not afford feerate %u" " (vs max %u)", feerate, max); msg = towire_update_fee(NULL, &peer->channel_id, feerate); enqueue_peer_msg(peer, take(msg)); } /* BOLT #2: * * A node MUST NOT send a `commitment_signed` message which does not * include any updates. */ changed_htlcs = tal_arr(tmpctx, const struct htlc *, 0); if (!channel_sending_commit(peer->channel, &changed_htlcs)) { status_trace("Can't send commit: nothing to send"); /* Covers the case where we've just been told to shutdown. */ maybe_send_shutdown(peer); peer->commit_timer = NULL; return; } peer->next_commit_sigs = calc_commitsigs(peer, peer, peer->next_index[REMOTE]); status_trace("Telling master we're about to commit..."); /* Tell master to save this next commit to database, then wait. */ msg = sending_commitsig_msg(NULL, peer->next_index[REMOTE], channel_feerate(peer->channel, REMOTE), changed_htlcs, &peer->next_commit_sigs->commit_sig, peer->next_commit_sigs->htlc_sigs); /* Message is empty; receiving it is the point. */ master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_SENDING_COMMITSIG_REPLY); status_trace("Sending commit_sig with %zu htlc sigs", tal_count(peer->next_commit_sigs->htlc_sigs)); peer->next_index[REMOTE]++; msg = towire_commitment_signed(NULL, &peer->channel_id, &peer->next_commit_sigs->commit_sig, peer->next_commit_sigs->htlc_sigs); enqueue_peer_msg(peer, take(msg)); peer->next_commit_sigs = tal_free(peer->next_commit_sigs); 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) { /* 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); } static u8 *make_revocation_msg(const struct peer *peer, u64 revoke_index) { struct pubkey oldpoint, point; struct sha256 old_commit_secret; /* Get secret. */ per_commit_secret(&peer->shaseed, &old_commit_secret, revoke_index); /* Sanity check that it corresponds to the point we sent. */ pubkey_from_privkey((struct privkey *)&old_commit_secret, &point); if (!per_commit_point(&peer->shaseed, &oldpoint, revoke_index)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid point %"PRIu64" for commit_point", revoke_index); status_trace("Sending revocation #%"PRIu64" for %s", revoke_index, type_to_string(tmpctx, struct pubkey, &oldpoint)); if (!pubkey_eq(&point, &oldpoint)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Invalid secret %s for commit_point", tal_hexstr(tmpctx, &old_commit_secret, sizeof(old_commit_secret))); /* We're revoking N-1th commit, sending N+1th point. */ if (!per_commit_point(&peer->shaseed, &point, revoke_index+2)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving next commit_point"); return towire_revoke_and_ack(peer, &peer->channel_id, &old_commit_secret, &point); } static void send_revocation(struct peer *peer) { /* Revoke previous commit. */ u8 *msg = make_revocation_msg(peer, peer->next_index[LOCAL]-1); /* From now on we apply changes to the next commitment */ peer->next_index[LOCAL]++; /* If this queues more changes on the other end, send commit. */ if (channel_sending_revoke_and_ack(peer->channel)) { status_trace("revoke_and_ack made pending: commit timer"); start_commit_timer(peer); } enqueue_peer_msg(peer, take(msg)); } static u8 *got_commitsig_msg(const tal_t *ctx, u64 local_commit_index, u32 local_feerate, const secp256k1_ecdsa_signature *commit_sig, const secp256k1_ecdsa_signature *htlc_sigs, const struct htlc **changed_htlcs, const struct bitcoin_tx *committx) { struct changed_htlc *changed; struct fulfilled_htlc *fulfilled; const struct failed_htlc **failed; struct added_htlc *added; struct secret *shared_secret; u8 *msg; changed = tal_arr(tmpctx, struct changed_htlc, 0); added = tal_arr(tmpctx, struct added_htlc, 0); shared_secret = tal_arr(tmpctx, struct secret, 0); failed = tal_arr(tmpctx, const struct failed_htlc *, 0); fulfilled = tal_arr(tmpctx, struct fulfilled_htlc, 0); for (size_t i = 0; i < tal_count(changed_htlcs); i++) { const struct htlc *htlc = changed_htlcs[i]; if (htlc->state == RCVD_ADD_COMMIT) { struct added_htlc *a = tal_arr_append(&added); struct secret *s = tal_arr_append(&shared_secret); a->id = htlc->id; a->amount_msat = htlc->msatoshi; 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)); *s = *htlc->shared_secret; } else if (htlc->state == RCVD_REMOVE_COMMIT) { if (htlc->r) { struct fulfilled_htlc *f; assert(!htlc->fail); f = tal_arr_append(&fulfilled); f->id = htlc->id; f->payment_preimage = *htlc->r; } else { struct failed_htlc **f; assert(htlc->fail); f = tal_arr_append(&failed); *f = tal(failed, struct failed_htlc); (*f)->id = htlc->id; (*f)->malformed = htlc->malformed; (*f)->failreason = cast_const(u8 *, htlc->fail); } } else { struct changed_htlc *c = tal_arr_append(&changed); assert(htlc->state == RCVD_REMOVE_ACK_COMMIT || htlc->state == RCVD_ADD_ACK_COMMIT); c->id = htlc->id; c->newstate = htlc->state; } } msg = towire_channel_got_commitsig(ctx, local_commit_index, local_feerate, commit_sig, htlc_sigs, added, shared_secret, fulfilled, failed, changed, committx); return msg; } static void handle_peer_commit_sig(struct peer *peer, const u8 *msg) { struct channel_id channel_id; secp256k1_ecdsa_signature commit_sig, *htlc_sigs; struct pubkey remote_htlckey, point; struct bitcoin_tx **txs; const struct htlc **htlc_map, **changed_htlcs; const u8 **wscripts; size_t i; changed_htlcs = tal_arr(msg, const struct htlc *, 0); if (!channel_rcvd_commit(peer->channel, &changed_htlcs)) { /* BOLT #2: * * A node MUST NOT send a `commitment_signed` message which * does not include any updates. */ peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "commit_sig with no changes"); } /* We were supposed to check this was affordable as we go. */ if (peer->channel->funder == REMOTE) assert(can_funder_afford_feerate(peer->channel, peer->channel->view[LOCAL] .feerate_per_kw)); if (!fromwire_commitment_signed(tmpctx, msg, &channel_id, &commit_sig, &htlc_sigs)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad commit_sig %s", tal_hex(msg, msg)); if (!per_commit_point(&peer->shaseed, &point, peer->next_index[LOCAL])) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving per_commit_point for %"PRIu64, peer->next_index[LOCAL]); txs = channel_txs(tmpctx, &htlc_map, &wscripts, peer->channel, &point, peer->next_index[LOCAL], LOCAL); if (!derive_simple_key(&peer->channel->basepoints[REMOTE].htlc, &point, &remote_htlckey)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving remote_htlckey"); status_trace("Derived key %s from basepoint %s, point %s", type_to_string(tmpctx, struct pubkey, &remote_htlckey), type_to_string(tmpctx, struct pubkey, &peer->channel->basepoints[REMOTE].htlc), type_to_string(tmpctx, struct pubkey, &point)); /* BOLT #2: * * A receiving node MUST fail the channel if `signature` is not valid * for its local commitment transaction once all pending updates are * applied. */ if (!check_tx_sig(txs[0], 0, NULL, wscripts[0], &peer->channel->funding_pubkey[REMOTE], &commit_sig)) { dump_htlcs(peer->channel, "receiving commit_sig"); peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad commit_sig signature %"PRIu64" %s for tx %s wscript %s key %s", peer->next_index[LOCAL], type_to_string(msg, secp256k1_ecdsa_signature, &commit_sig), type_to_string(msg, struct bitcoin_tx, txs[0]), tal_hex(msg, wscripts[0]), type_to_string(msg, struct pubkey, &peer->channel->funding_pubkey [REMOTE])); } /* BOLT #2: * * A receiving node MUST fail the channel if `num_htlcs` is not equal * to the number of HTLC outputs in the local commitment transaction * once all pending updates are applied. */ if (tal_count(htlc_sigs) != tal_count(txs) - 1) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Expected %zu htlc sigs, not %zu", tal_count(txs) - 1, tal_count(htlc_sigs)); /* BOLT #2: * * A receiving node MUST fail * the channel if any `htlc_signature` is not valid for the * corresponding HTLC transaction. */ for (i = 0; i < tal_count(htlc_sigs); i++) { if (!check_tx_sig(txs[1+i], 0, NULL, wscripts[1+i], &remote_htlckey, &htlc_sigs[i])) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad commit_sig signature %s for htlc %s wscript %s key %s", type_to_string(msg, secp256k1_ecdsa_signature, &htlc_sigs[i]), type_to_string(msg, struct bitcoin_tx, txs[1+i]), tal_hex(msg, wscripts[1+i]), type_to_string(msg, struct pubkey, &remote_htlckey)); } status_trace("Received commit_sig with %zu htlc sigs", tal_count(htlc_sigs)); /* Tell master daemon, then wait for ack. */ msg = got_commitsig_msg(NULL, peer->next_index[LOCAL], channel_feerate(peer->channel, LOCAL), &commit_sig, htlc_sigs, changed_htlcs, txs[0]); master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_GOT_COMMITSIG_REPLY); return send_revocation(peer); } static u8 *got_revoke_msg(const tal_t *ctx, u64 revoke_num, const struct sha256 *per_commitment_secret, const struct pubkey *next_per_commit_point, const struct htlc **changed_htlcs) { u8 *msg; struct changed_htlc *changed = tal_arr(tmpctx, struct changed_htlc, 0); for (size_t i = 0; i < tal_count(changed_htlcs); i++) { struct changed_htlc *c = tal_arr_append(&changed); const struct htlc *htlc = changed_htlcs[i]; status_trace("HTLC %"PRIu64"[%s] => %s", htlc->id, side_to_str(htlc_owner(htlc)), htlc_state_name(htlc->state)); c->id = changed_htlcs[i]->id; c->newstate = changed_htlcs[i]->state; } msg = towire_channel_got_revoke(ctx, revoke_num, per_commitment_secret, next_per_commit_point, changed); return msg; } static void handle_peer_revoke_and_ack(struct peer *peer, const u8 *msg) { struct sha256 old_commit_secret; struct privkey privkey; struct channel_id channel_id; struct pubkey per_commit_point, next_per_commit; const struct htlc **changed_htlcs = tal_arr(msg, const struct htlc *, 0); if (!fromwire_revoke_and_ack(msg, &channel_id, &old_commit_secret, &next_per_commit)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad revoke_and_ack %s", tal_hex(msg, msg)); } if (peer->revocations_received != peer->next_index[REMOTE] - 2) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Unexpected revoke_and_ack"); } /* BOLT #2: * * A receiving node MUST check that `per_commitment_secret` generates * the previous `per_commitment_point`, and MUST fail if it does * not. */ memcpy(&privkey, &old_commit_secret, sizeof(privkey)); if (!pubkey_from_privkey(&privkey, &per_commit_point)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad privkey %s", type_to_string(msg, struct privkey, &privkey)); } if (!pubkey_eq(&per_commit_point, &peer->old_remote_per_commit)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Wrong privkey %s for %"PRIu64" %s", type_to_string(msg, struct privkey, &privkey), peer->next_index[LOCAL]-2, type_to_string(msg, struct pubkey, &peer->old_remote_per_commit)); } /* We start timer even if this returns false: we might have delayed * commit because we were waiting for this! */ if (channel_rcvd_revoke_and_ack(peer->channel, &changed_htlcs)) status_trace("Commits outstanding after recv revoke_and_ack"); else status_trace("No commits outstanding after recv revoke_and_ack"); /* Tell master about things this locks in, wait for response */ msg = got_revoke_msg(NULL, peer->revocations_received++, &old_commit_secret, &next_per_commit, changed_htlcs); master_wait_sync_reply(tmpctx, peer, take(msg), WIRE_CHANNEL_GOT_REVOKE_REPLY); peer->old_remote_per_commit = peer->remote_per_commit; peer->remote_per_commit = next_per_commit; status_trace("revoke_and_ack %s: remote_per_commit = %s, old_remote_per_commit = %s", side_to_str(peer->channel->funder), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit)); start_commit_timer(peer); } static void handle_peer_fulfill_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; struct preimage preimage; enum channel_remove_err e; if (!fromwire_update_fulfill_htlc(msg, &channel_id, &id, &preimage)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fulfill_htlc %s", tal_hex(msg, msg)); } e = channel_fulfill_htlc(peer->channel, LOCAL, id, &preimage); switch (e) { case CHANNEL_ERR_REMOVE_OK: /* FIXME: We could send preimages to master immediately. */ start_commit_timer(peer); return; /* These shouldn't happen, because any offered HTLC (which would give * us the preimage) should have timed out long before. If we * were to get preimages from other sources, this could happen. */ case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fulfill_htlc: failed to fulfill %" PRIu64 " error %s", id, channel_remove_err_name(e)); } abort(); } static void handle_peer_fail_htlc(struct peer *peer, const u8 *msg) { struct channel_id channel_id; u64 id; enum channel_remove_err e; u8 *reason; struct htlc *htlc; if (!fromwire_update_fail_htlc(msg, msg, &channel_id, &id, &reason)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fulfill_htlc %s", tal_hex(msg, msg)); } e = channel_fail_htlc(peer->channel, LOCAL, id, NULL); switch (e) { case CHANNEL_ERR_REMOVE_OK: /* Save reason for when we tell master. */ htlc = channel_get_htlc(peer->channel, LOCAL, id); htlc->fail = tal_steal(htlc, reason); start_commit_timer(peer); return; case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, peer->gossip_index, &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; u8 *fail; if (!fromwire_update_fail_malformed_htlc(msg, &channel_id, &id, &sha256_of_onion, &failure_code)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fail_malformed_htlc %s", tal_hex(msg, msg)); } /* BOLT #2: * * A receiving node MUST fail the channel if the `BADONION` bit in * `failure_code` is not set for `update_fail_malformed_htlc`. */ if (!(failure_code & BADONION)) { peer_failed(&peer->cs, peer->gossip_index, &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: /* FIXME: Do this! */ /* BOLT #2: * * A receiving node MAY check the `sha256_of_onion` * in `update_fail_malformed_htlc` and MAY retry or choose an * alternate error response if it does not match the onion it * sent. */ /* BOLT #2: * * Otherwise, a receiving node which has an outgoing HTLC * canceled by `update_fail_malformed_htlc` MUST return an * error in the `update_fail_htlc` sent to the link which * originally sent the HTLC using the `failure_code` given and * setting the data to `sha256_of_onion`. */ fail = tal_arr(htlc, u8, 0); towire_u16(&fail, failure_code); towire_sha256(&fail, &sha256_of_onion); htlc->fail = fail; start_commit_timer(peer); return; case CHANNEL_ERR_NO_SUCH_ID: case CHANNEL_ERR_ALREADY_FULFILLED: case CHANNEL_ERR_HTLC_UNCOMMITTED: case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE: case CHANNEL_ERR_BAD_PREIMAGE: peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad update_fail_malformed_htlc: failed to remove %" PRIu64 " error %s", id, channel_remove_err_name(e)); } abort(); } static void handle_pong(struct peer *peer, const u8 *pong) { const char *err = got_pong(pong, &peer->num_pings_outstanding); if (err) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "%s", err); wire_sync_write(MASTER_FD, take(towire_channel_ping_reply(NULL, tal_len(pong)))); } static void handle_peer_shutdown(struct peer *peer, const u8 *shutdown) { struct channel_id channel_id; u8 *scriptpubkey, *msg; msg = create_channel_update(NULL, peer, true); wire_sync_write(GOSSIP_FD, take(msg)); if (!fromwire_shutdown(peer, shutdown, &channel_id, &scriptpubkey)) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Bad shutdown %s", tal_hex(peer, shutdown)); /* Tell master: we don't have to wait because on reconnect other end * will re-send anyway. */ wire_sync_write(MASTER_FD, take(towire_channel_got_shutdown(NULL, scriptpubkey))); peer->shutdown_sent[REMOTE] = true; /* BOLT #2: * * A receiving node: * ... * - once there are no outstanding updates on the peer, UNLESS * it has already sent a `shutdown`: * - MUST reply to a `shutdown` message with a `shutdown` */ if (!peer->shutdown_sent[LOCAL]) { peer->send_shutdown = true; start_commit_timer(peer); } billboard_update(peer); } /* Note: msg came from read_peer_msg() which handles pings, gossip, * wrong channel, errors */ static void peer_in(struct peer *peer, const u8 *msg) { enum wire_type type = fromwire_peektype(msg); /* Must get funding_locked before almost anything. */ if (!peer->funding_locked[REMOTE]) { if (type != WIRE_FUNDING_LOCKED && type != WIRE_PONG) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "%s (%u) before funding locked", wire_type_name(type), type); } } switch (type) { case WIRE_FUNDING_LOCKED: handle_peer_funding_locked(peer, msg); return; case WIRE_ANNOUNCEMENT_SIGNATURES: handle_peer_announcement_signatures(peer, msg); return; case WIRE_UPDATE_ADD_HTLC: handle_peer_add_htlc(peer, msg); return; case WIRE_COMMITMENT_SIGNED: handle_peer_commit_sig(peer, msg); return; case WIRE_UPDATE_FEE: handle_peer_feechange(peer, msg); return; case WIRE_REVOKE_AND_ACK: handle_peer_revoke_and_ack(peer, msg); return; case WIRE_UPDATE_FULFILL_HTLC: handle_peer_fulfill_htlc(peer, msg); return; case WIRE_UPDATE_FAIL_HTLC: handle_peer_fail_htlc(peer, msg); return; case WIRE_UPDATE_FAIL_MALFORMED_HTLC: handle_peer_fail_malformed_htlc(peer, msg); return; case WIRE_PONG: handle_pong(peer, msg); return; case WIRE_SHUTDOWN: handle_peer_shutdown(peer, msg); return; case WIRE_INIT: case WIRE_OPEN_CHANNEL: case WIRE_ACCEPT_CHANNEL: case WIRE_FUNDING_CREATED: case WIRE_FUNDING_SIGNED: case WIRE_CHANNEL_REESTABLISH: case WIRE_CLOSING_SIGNED: break; /* These are all swallowed by read_peer_msg */ case WIRE_CHANNEL_ANNOUNCEMENT: case WIRE_CHANNEL_UPDATE: case WIRE_NODE_ANNOUNCEMENT: case WIRE_PING: case WIRE_ERROR: abort(); } peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Peer sent unknown message %u (%s)", type, wire_type_name(type)); } static void peer_conn_broken(struct peer *peer) { /* If we have signatures, send an update to say we're disabled. */ if (peer->have_sigs[LOCAL] && peer->have_sigs[REMOTE]) { u8 *cupdate = create_channel_update(NULL, peer, true); wire_sync_write(GOSSIP_FD, take(cupdate)); } peer_failed_connection_lost(); } static void resend_revoke(struct peer *peer) { /* Current commit is peer->next_index[LOCAL]-1, revoke prior */ u8 *msg = make_revocation_msg(peer, peer->next_index[LOCAL]-2); enqueue_peer_msg(peer, take(msg)); } static void send_fail_or_fulfill(struct peer *peer, const struct htlc *h) { u8 *msg; if (h->malformed) { struct sha256 sha256_of_onion; sha256(&sha256_of_onion, h->routing, tal_len(h->routing)); msg = towire_update_fail_malformed_htlc(NULL, &peer->channel_id, h->id, &sha256_of_onion, h->malformed); } else if (h->fail) { msg = towire_update_fail_htlc(NULL, &peer->channel_id, h->id, h->fail); } else if (h->r) { msg = towire_update_fulfill_htlc(NULL, &peer->channel_id, h->id, h->r); } else peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "HTLC %"PRIu64" state %s not failed/fulfilled", h->id, htlc_state_name(h->state)); enqueue_peer_msg(peer, take(msg)); } static void resend_commitment(struct peer *peer, const struct changed_htlc *last) { size_t i; struct commit_sigs *commit_sigs; u8 *msg; /* BOLT #2: * * If `next_local_commitment_number` is equal to the commitment number * of the last `commitment_signed` message the receiving node has * sent, it MUST reuse the same commitment number for its next * `commitment_signed` */ /* In our case, we consider ourselves already committed to this, so * retransmission is simplest. */ for (i = 0; i < tal_count(last); i++) { const struct htlc *h; h = channel_get_htlc(peer->channel, htlc_state_owner(last[i].newstate), last[i].id); /* I think this can happen if we actually received revoke_and_ack * then they asked for a retransmit */ if (!h) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "Can't find HTLC %"PRIu64" to resend", last[i].id); if (h->state == SENT_ADD_COMMIT) { u8 *msg = towire_update_add_htlc(peer, &peer->channel_id, h->id, h->msatoshi, &h->rhash, abs_locktime_to_blocks( &h->expiry), h->routing); enqueue_peer_msg(peer, take(msg)); } else if (h->state == SENT_REMOVE_COMMIT) { send_fail_or_fulfill(peer, h); } } /* Make sure they have the correct fee. */ if (peer->channel->funder == LOCAL) { msg = towire_update_fee(NULL, &peer->channel_id, channel_feerate(peer->channel, REMOTE)); enqueue_peer_msg(peer, take(msg)); } /* Re-send the commitment_signed itself. */ commit_sigs = calc_commitsigs(peer, peer, peer->next_index[REMOTE]-1); msg = towire_commitment_signed(NULL, &peer->channel_id, &commit_sigs->commit_sig, commit_sigs->htlc_sigs); enqueue_peer_msg(peer, take(msg)); tal_free(commit_sigs); assert(peer->revocations_received == peer->next_index[REMOTE] - 2); } /* Our local wrapper around read_peer_msg */ static void channeld_io_error(struct peer *peer) { peer_conn_broken(peer); } static bool channeld_send_reply(struct crypto_state *cs UNUSED, int peer_fd UNUSED, const u8 *msg UNUSED, struct peer *peer) { enqueue_peer_msg(peer, msg); return true; } static u8 *channeld_read_peer_msg(struct peer *peer) { return read_peer_msg(peer, &peer->cs, peer->gossip_index, &peer->channel_id, channeld_send_reply, channeld_io_error, peer); } static void peer_reconnect(struct peer *peer) { struct channel_id channel_id; /* Note: BOLT #2 uses these names, which are sender-relative! */ u64 next_local_commitment_number, next_remote_revocation_number; bool retransmit_revoke_and_ack; struct htlc_map_iter it; const struct htlc *htlc; u8 *msg, *cupdate; /* BOLT #2: * * On reconnection, a node MUST transmit `channel_reestablish` for * each channel, and MUST wait for to receive the other node's * `channel_reestablish` message before sending any other messages for * that channel. * * The sending node MUST set `next_local_commitment_number` to the * commitment number of the next `commitment_signed` it expects to * receive, and MUST set `next_remote_revocation_number` to the * commitment number of the next `revoke_and_ack` message it expects * to receive. */ msg = towire_channel_reestablish(NULL, &peer->channel_id, peer->next_index[LOCAL], peer->revocations_received); if (!sync_crypto_write(&peer->cs, PEER_FD, take(msg))) peer_failed_connection_lost(); peer_billboard(false, "Sent reestablish, waiting for theirs"); /* Read until they say something interesting */ while ((msg = channeld_read_peer_msg(peer)) == NULL) clean_tmpctx(); if (!fromwire_channel_reestablish(msg, &channel_id, &next_local_commitment_number, &next_remote_revocation_number)) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "bad reestablish msg: %s %s", wire_type_name(fromwire_peektype(msg)), tal_hex(msg, msg)); } status_trace("Got reestablish commit=%"PRIu64" revoke=%"PRIu64, next_local_commitment_number, next_remote_revocation_number); /* BOLT #2: * * If `next_local_commitment_number` is 1 in both the * `channel_reestablish` it sent and received, then the node MUST * retransmit `funding_locked`, otherwise it MUST NOT. */ if (peer->funding_locked[LOCAL] && peer->next_index[LOCAL] == 1 && next_local_commitment_number == 1) { u8 *msg; struct pubkey next_per_commit_point; /* Contains per commit point #1, for first post-opening commit */ per_commit_point(&peer->shaseed, &next_per_commit_point, 1); msg = towire_funding_locked(NULL, &peer->channel_id, &next_per_commit_point); enqueue_peer_msg(peer, take(msg)); } /* Note: next_index is the index of the current commit we're working * on, but BOLT #2 refers to the *last* commit index, so we -1 where * required. */ /* BOLT #2: * * If `next_remote_revocation_number` is equal to the commitment * number of the last `revoke_and_ack` the receiving node has sent and the receiving node has not already received a `closing_signed`, it * MUST re-send the `revoke_and_ack`, otherwise if * `next_remote_revocation_number` is not equal to one greater than * the commitment number of the last `revoke_and_ack` the receiving * node has sent (or equal to zero if none have been sent), it SHOULD * fail the channel. */ if (next_remote_revocation_number == peer->next_index[LOCAL] - 2) { /* Don't try to retransmit revocation index -1! */ if (peer->next_index[LOCAL] < 2) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "bad reestablish revocation_number: %" PRIu64, next_remote_revocation_number); } retransmit_revoke_and_ack = true; } else if (next_remote_revocation_number != peer->next_index[LOCAL] - 1) { peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "bad reestablish revocation_number: %"PRIu64 " vs %"PRIu64, next_remote_revocation_number, peer->next_index[LOCAL]); } else retransmit_revoke_and_ack = false; /* We have to re-send in the same order we sent originally: * revoke_and_ack (usually) alters our next commitment. */ if (retransmit_revoke_and_ack && !peer->last_was_revoke) resend_revoke(peer); /* BOLT #2: * * If `next_local_commitment_number` is equal to the commitment number * of the last `commitment_signed` message the receiving node has * sent, it MUST reuse the same commitment number for its next * `commitment_signed` */ if (next_local_commitment_number == peer->next_index[REMOTE] - 1) { /* We completed opening, we don't re-transmit that one! */ if (next_local_commitment_number == 0) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "bad reestablish commitment_number: %" PRIu64, next_local_commitment_number); resend_commitment(peer, peer->last_sent_commit); /* BOLT #2: * * ... otherwise if `next_local_commitment_number` is not one greater * than the commitment number of the last `commitment_signed` message * the receiving node has sent, it SHOULD fail the channel. */ } else if (next_local_commitment_number != peer->next_index[REMOTE]) peer_failed(&peer->cs, peer->gossip_index, &peer->channel_id, "bad reestablish commitment_number: %"PRIu64 " vs %"PRIu64, next_local_commitment_number, peer->next_index[REMOTE]); /* This covers the case where we sent revoke after commit. */ if (retransmit_revoke_and_ack && peer->last_was_revoke) resend_revoke(peer); /* BOLT #2: * * On reconnection if the node has sent a previous `closing_signed` it * MUST send another `closing_signed`, otherwise if the node has sent * a previous `shutdown` it MUST retransmit it. */ /* If we had sent `closing_signed`, we'd be in closingd. */ maybe_send_shutdown(peer); /* Corner case: we didn't send shutdown before because update_add_htlc * pending, but now they're cleared by restart, and we're actually * complete. In that case, their `shutdown` will trigger us. */ /* Start commit timer: if we sent revoke we might need it. */ start_commit_timer(peer); /* Now, re-send any that we're supposed to be failing. */ for (htlc = htlc_map_first(peer->channel->htlcs, &it); htlc; htlc = htlc_map_next(peer->channel->htlcs, &it)) { if (htlc->state == SENT_REMOVE_HTLC) send_fail_or_fulfill(peer, htlc); } /* Reenable channel by sending a channel_update without the * disable flag */ cupdate = create_channel_update(NULL, peer, false); wire_sync_write(GOSSIP_FD, cupdate); enqueue_peer_msg(peer, take(cupdate)); /* Corner case: we will get upset with them if they send * commitment_signed with no changes. But it could be that we sent a * feechange, they acked, and now they want to commit it; we can't * even tell by seeing if fees are different (short of saving full fee * state in database) since it could be a tiny feechange, or two * feechanges which cancelled out. */ if (peer->channel->funder == LOCAL) peer->channel->changes_pending[LOCAL] = true; peer_billboard(true, "Reconnected, and reestablished."); } static void handle_funding_locked(struct peer *peer, const u8 *msg) { struct pubkey next_per_commit_point; if (!fromwire_channel_funding_locked(msg, &peer->short_channel_ids[LOCAL])) master_badmsg(WIRE_CHANNEL_FUNDING_LOCKED, msg); per_commit_point(&peer->shaseed, &next_per_commit_point, peer->next_index[LOCAL]); status_trace("funding_locked: sending commit index %"PRIu64": %s", peer->next_index[LOCAL], type_to_string(tmpctx, struct pubkey, &next_per_commit_point)); msg = towire_funding_locked(NULL, &peer->channel_id, &next_per_commit_point); enqueue_peer_msg(peer, take(msg)); peer->funding_locked[LOCAL] = true; if (peer->funding_locked[REMOTE]) { wire_sync_write(MASTER_FD, take(towire_channel_normal_operation(NULL))); } billboard_update(peer); /* Send temporary or final announcements */ send_temporary_announcement(peer); send_announcement_signatures(peer); } static void handle_funding_announce_depth(struct peer *peer) { peer->announce_depth_reached = true; send_announcement_signatures(peer); /* Only send the announcement and update if the other end gave * us its sig */ if (peer->have_sigs[REMOTE]) announce_channel(peer); } static void handle_offer_htlc(struct peer *peer, const u8 *inmsg) { u8 *msg; u32 cltv_expiry; u64 amount_msat; struct sha256 payment_hash; u8 onion_routing_packet[TOTAL_PACKET_SIZE]; enum channel_add_err e; enum onion_type failcode; /* Subtle: must be tal_arr since we marshal using tal_len() */ const char *failmsg; if (!peer->funding_locked[LOCAL] || !peer->funding_locked[REMOTE]) status_failed(STATUS_FAIL_MASTER_IO, "funding not locked for offer_htlc"); if (!fromwire_channel_offer_htlc(inmsg, &amount_msat, &cltv_expiry, &payment_hash, onion_routing_packet)) master_badmsg(WIRE_CHANNEL_OFFER_HTLC, inmsg); e = channel_add_htlc(peer->channel, LOCAL, peer->htlc_id, amount_msat, cltv_expiry, &payment_hash, onion_routing_packet, NULL); status_trace("Adding HTLC %"PRIu64" msat=%"PRIu64" cltv=%u gave %s", peer->htlc_id, amount_msat, 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_msat, &payment_hash, cltv_expiry, onion_routing_packet); enqueue_peer_msg(peer, take(msg)); start_commit_timer(peer); /* Tell the master. */ msg = towire_channel_offer_htlc_reply(NULL, peer->htlc_id, 0, NULL); wire_sync_write(MASTER_FD, take(msg)); peer->htlc_id++; return; case CHANNEL_ERR_INVALID_EXPIRY: failcode = WIRE_INCORRECT_CLTV_EXPIRY; failmsg = tal_fmt(inmsg, "Invalid cltv_expiry %u", cltv_expiry); goto failed; case CHANNEL_ERR_DUPLICATE: case CHANNEL_ERR_DUPLICATE_ID_DIFFERENT: status_failed(STATUS_FAIL_MASTER_IO, "Duplicate HTLC %"PRIu64, peer->htlc_id); /* FIXME: Fuzz the boundaries a bit to avoid probing? */ case CHANNEL_ERR_MAX_HTLC_VALUE_EXCEEDED: /* FIXME: We should advertise this? */ failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Maximum value exceeded"); goto failed; case CHANNEL_ERR_CHANNEL_CAPACITY_EXCEEDED: failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Capacity exceeded"); goto failed; case CHANNEL_ERR_HTLC_BELOW_MINIMUM: failcode = WIRE_AMOUNT_BELOW_MINIMUM; failmsg = tal_fmt(inmsg, "HTLC too small (%u minimum)", htlc_minimum_msat(peer->channel, REMOTE)); goto failed; case CHANNEL_ERR_TOO_MANY_HTLCS: failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; failmsg = tal_fmt(inmsg, "Too many HTLCs"); goto failed; } /* Shouldn't return anything else! */ abort(); failed: /* Note: tal_fmt doesn't set tal_len() to exact length, so fix here. */ tal_resize(&failmsg, strlen(failmsg)+1); msg = towire_channel_offer_htlc_reply(NULL, 0, failcode, (u8*)failmsg); wire_sync_write(MASTER_FD, take(msg)); } static void handle_feerates(struct peer *peer, const u8 *inmsg) { u32 feerate; if (!fromwire_channel_feerates(inmsg, &feerate, &peer->feerate_min, &peer->feerate_max)) master_badmsg(WIRE_CHANNEL_FEERATES, inmsg); /* BOLT #2: * * The node which is responsible for paying the bitcoin fee SHOULD * send `update_fee` to ensure the current fee rate is sufficient for * timely processing of the commitment transaction by a significant * margin. */ if (peer->channel->funder == LOCAL) { peer->desired_feerate = feerate; start_commit_timer(peer); } else { /* BOLT #2: * * The node which is not responsible for paying the bitcoin * fee MUST NOT send `update_fee`. */ /* FIXME: We could drop to chain if fees are too low, but * that's fraught too. */ } } static void handle_preimage(struct peer *peer, const u8 *inmsg) { u8 *msg; u64 id; struct preimage preimage; if (!fromwire_channel_fulfill_htlc(inmsg, &id, &preimage)) master_badmsg(WIRE_CHANNEL_FULFILL_HTLC, inmsg); switch (channel_fulfill_htlc(peer->channel, REMOTE, id, &preimage)) { case CHANNEL_ERR_REMOVE_OK: msg = towire_update_fulfill_htlc(NULL, &peer->channel_id, id, &preimage); enqueue_peer_msg(peer, take(msg)); 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", id); } abort(); } static u8 *foreign_channel_update(const tal_t *ctx, struct peer *peer, const struct short_channel_id *scid) { u8 *msg, *update; msg = towire_gossip_get_update(NULL, scid); msg = gossipd_wait_sync_reply(tmpctx, peer, take(msg), WIRE_GOSSIP_GET_UPDATE_REPLY); if (!fromwire_gossip_get_update_reply(ctx, msg, &update)) status_failed(STATUS_FAIL_GOSSIP_IO, "Invalid update reply"); return update; } static u8 *make_failmsg(const tal_t *ctx, struct peer *peer, const struct htlc *htlc, enum onion_type failcode, const struct short_channel_id *scid) { u8 *msg, *channel_update = NULL; u32 cltv_expiry = abs_locktime_to_blocks(&htlc->expiry); switch (failcode) { case WIRE_INVALID_REALM: msg = towire_invalid_realm(ctx); goto done; case WIRE_TEMPORARY_NODE_FAILURE: msg = towire_temporary_node_failure(ctx); goto done; case WIRE_PERMANENT_NODE_FAILURE: msg = towire_permanent_node_failure(ctx); goto done; case WIRE_REQUIRED_NODE_FEATURE_MISSING: msg = towire_required_node_feature_missing(ctx); goto done; case WIRE_TEMPORARY_CHANNEL_FAILURE: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_temporary_channel_failure(ctx, channel_update); goto done; case WIRE_CHANNEL_DISABLED: msg = towire_channel_disabled(ctx); goto done; case WIRE_PERMANENT_CHANNEL_FAILURE: msg = towire_permanent_channel_failure(ctx); goto done; case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING: msg = towire_required_channel_feature_missing(ctx); goto done; case WIRE_UNKNOWN_NEXT_PEER: msg = towire_unknown_next_peer(ctx); goto done; case WIRE_AMOUNT_BELOW_MINIMUM: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_amount_below_minimum(ctx, htlc->msatoshi, channel_update); goto done; case WIRE_FEE_INSUFFICIENT: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_fee_insufficient(ctx, htlc->msatoshi, channel_update); goto done; case WIRE_INCORRECT_CLTV_EXPIRY: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_incorrect_cltv_expiry(ctx, cltv_expiry, channel_update); goto done; case WIRE_EXPIRY_TOO_SOON: channel_update = foreign_channel_update(ctx, peer, scid); msg = towire_expiry_too_soon(ctx, channel_update); goto done; case WIRE_EXPIRY_TOO_FAR: msg = towire_expiry_too_far(ctx); goto done; case WIRE_UNKNOWN_PAYMENT_HASH: msg = towire_unknown_payment_hash(ctx); goto done; case WIRE_INCORRECT_PAYMENT_AMOUNT: msg = towire_incorrect_payment_amount(ctx); goto done; case WIRE_FINAL_EXPIRY_TOO_SOON: msg = towire_final_expiry_too_soon(ctx); goto done; case WIRE_FINAL_INCORRECT_CLTV_EXPIRY: msg = towire_final_incorrect_cltv_expiry(ctx, cltv_expiry); goto done; case WIRE_FINAL_INCORRECT_HTLC_AMOUNT: msg = towire_final_incorrect_htlc_amount(ctx, htlc->msatoshi); goto done; case WIRE_INVALID_ONION_VERSION: case WIRE_INVALID_ONION_HMAC: case WIRE_INVALID_ONION_KEY: break; } status_failed(STATUS_FAIL_INTERNAL_ERROR, "Asked to create failmsg %u (%s)", failcode, onion_type_name(failcode)); done: tal_free(channel_update); return msg; } static void handle_fail(struct peer *peer, const u8 *inmsg) { u8 *msg; u64 id; u8 *errpkt; u16 failcode; struct short_channel_id scid; enum channel_remove_err e; struct htlc *h; if (!fromwire_channel_fail_htlc(inmsg, inmsg, &id, &errpkt, &failcode, &scid)) master_badmsg(WIRE_CHANNEL_FAIL_HTLC, inmsg); if (failcode && tal_len(errpkt)) status_failed(STATUS_FAIL_MASTER_IO, "Invalid channel_fail_htlc: %s with errpkt?", onion_type_name(failcode)); e = channel_fail_htlc(peer->channel, REMOTE, id, &h); switch (e) { case CHANNEL_ERR_REMOVE_OK: if (failcode & BADONION) { struct sha256 sha256_of_onion; status_trace("Failing %"PRIu64" with code %u", id, failcode); sha256(&sha256_of_onion, h->routing, tal_len(h->routing)); msg = towire_update_fail_malformed_htlc(peer, &peer->channel_id, id, &sha256_of_onion, failcode); } else { u8 *reply; u8 *failmsg; if (failcode) { failmsg = make_failmsg(inmsg, peer, h, failcode, &scid); errpkt = create_onionreply(inmsg, h->shared_secret, failmsg); } reply = wrap_onionreply(inmsg, h->shared_secret, errpkt); msg = towire_update_fail_htlc(peer, &peer->channel_id, id, reply); } enqueue_peer_msg(peer, take(msg)); 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", id, channel_remove_err_name(e)); } abort(); } static void handle_ping_cmd(struct peer *peer, const u8 *inmsg) { u16 num_pong_bytes, ping_len; u8 *ping; if (!fromwire_channel_ping(inmsg, &num_pong_bytes, &ping_len)) master_badmsg(WIRE_CHANNEL_PING, inmsg); ping = make_ping(NULL, num_pong_bytes, ping_len); if (tal_len(ping) > 65535) status_failed(STATUS_FAIL_MASTER_IO, "Oversize channel_ping"); enqueue_peer_msg(peer, take(ping)); status_trace("sending ping expecting %sresponse", num_pong_bytes >= 65532 ? "no " : ""); /* BOLT #1: * * if `num_pong_bytes` is less than 65532 it MUST respond by sending a * `pong` message with `byteslen` equal to `num_pong_bytes`, otherwise * it MUST ignore the `ping`. */ if (num_pong_bytes >= 65532) wire_sync_write(MASTER_FD, take(towire_channel_ping_reply(NULL, 0))); else peer->num_pings_outstanding++; } static void handle_shutdown_cmd(struct peer *peer, const u8 *inmsg) { if (!fromwire_channel_send_shutdown(inmsg)) master_badmsg(WIRE_CHANNEL_SEND_SHUTDOWN, inmsg); /* We can't send this until commit (if any) is done, so start timer. */ peer->send_shutdown = true; start_commit_timer(peer); } #if DEVELOPER static void handle_dev_reenable_commit(struct peer *peer) { dev_suppress_commit = false; start_commit_timer(peer); status_trace("dev_reenable_commit"); wire_sync_write(MASTER_FD, take(towire_channel_dev_reenable_commit_reply(NULL))); } #endif static void req_in(struct peer *peer, const u8 *msg) { enum channel_wire_type t = fromwire_peektype(msg); switch (t) { case WIRE_CHANNEL_FUNDING_LOCKED: handle_funding_locked(peer, msg); return; case WIRE_CHANNEL_FUNDING_ANNOUNCE_DEPTH: handle_funding_announce_depth(peer); return; case WIRE_CHANNEL_OFFER_HTLC: handle_offer_htlc(peer, msg); return; case WIRE_CHANNEL_FEERATES: handle_feerates(peer, msg); return; case WIRE_CHANNEL_FULFILL_HTLC: handle_preimage(peer, msg); return; case WIRE_CHANNEL_FAIL_HTLC: handle_fail(peer, msg); return; case WIRE_CHANNEL_PING: handle_ping_cmd(peer, msg); return; case WIRE_CHANNEL_SEND_SHUTDOWN: handle_shutdown_cmd(peer, msg); return; case WIRE_CHANNEL_DEV_REENABLE_COMMIT: #if DEVELOPER handle_dev_reenable_commit(peer); return; #endif /* DEVELOPER */ case WIRE_CHANNEL_NORMAL_OPERATION: case WIRE_CHANNEL_INIT: case WIRE_CHANNEL_OFFER_HTLC_REPLY: case WIRE_CHANNEL_PING_REPLY: case WIRE_CHANNEL_SENDING_COMMITSIG: case WIRE_CHANNEL_GOT_COMMITSIG: case WIRE_CHANNEL_GOT_REVOKE: case WIRE_CHANNEL_SENDING_COMMITSIG_REPLY: case WIRE_CHANNEL_GOT_COMMITSIG_REPLY: case WIRE_CHANNEL_GOT_REVOKE_REPLY: case WIRE_CHANNEL_GOT_FUNDING_LOCKED: case WIRE_CHANNEL_GOT_SHUTDOWN: case WIRE_CHANNEL_SHUTDOWN_COMPLETE: case WIRE_CHANNEL_DEV_REENABLE_COMMIT_REPLY: break; } master_badmsg(-1, msg); } static void init_shared_secrets(struct channel *channel, const struct added_htlc *htlcs, const enum htlc_state *hstates) { for (size_t i = 0; i < tal_count(htlcs); i++) { struct htlc *htlc; /* We only derive this for HTLCs *they* added. */ if (htlc_state_owner(hstates[i]) != REMOTE) continue; htlc = channel_get_htlc(channel, REMOTE, htlcs[i].id); htlc->shared_secret = tal(htlc, struct secret); get_shared_secret(htlc, htlc->shared_secret); } } /* We do this synchronously. */ static void init_channel(struct peer *peer) { struct privkey seed; struct basepoints points[NUM_SIDES]; u64 funding_satoshi; u16 funding_txout; u64 local_msatoshi; struct pubkey funding_pubkey[NUM_SIDES]; struct bitcoin_txid funding_txid; enum side funder; enum htlc_state *hstates; struct fulfilled_htlc *fulfilled; enum side *fulfilled_sides; struct failed_htlc **failed; enum side *failed_sides; struct added_htlc *htlcs; bool reconnected; u8 *funding_signed; u8 *msg; u32 feerate_per_kw[NUM_SIDES]; assert(!(fcntl(MASTER_FD, F_GETFL) & O_NONBLOCK)); status_setup_sync(MASTER_FD); msg = wire_sync_read(peer, MASTER_FD); if (!fromwire_channel_init(peer, msg, &peer->chain_hash, &funding_txid, &funding_txout, &funding_satoshi, &peer->conf[LOCAL], &peer->conf[REMOTE], feerate_per_kw, &peer->feerate_min, &peer->feerate_max, &peer->their_commit_sig, &peer->cs, &peer->gossip_index, &funding_pubkey[REMOTE], &points[REMOTE].revocation, &points[REMOTE].payment, &points[REMOTE].htlc, &points[REMOTE].delayed_payment, &peer->remote_per_commit, &peer->old_remote_per_commit, &funder, &peer->fee_base, &peer->fee_per_satoshi, &local_msatoshi, &seed, &peer->node_ids[LOCAL], &peer->node_ids[REMOTE], &peer->commit_msec, &peer->cltv_delta, &peer->last_was_revoke, &peer->last_sent_commit, &peer->next_index[LOCAL], &peer->next_index[REMOTE], &peer->revocations_received, &peer->htlc_id, &htlcs, &hstates, &fulfilled, &fulfilled_sides, &failed, &failed_sides, &peer->funding_locked[LOCAL], &peer->funding_locked[REMOTE], &peer->short_channel_ids[LOCAL], &reconnected, &peer->send_shutdown, &peer->shutdown_sent[REMOTE], &peer->final_scriptpubkey, &peer->channel_flags, &funding_signed)) master_badmsg(WIRE_CHANNEL_INIT, msg); status_trace("init %s: remote_per_commit = %s, old_remote_per_commit = %s" " next_idx_local = %"PRIu64 " next_idx_remote = %"PRIu64 " revocations_received = %"PRIu64 " feerates %u/%u (range %u-%u)", side_to_str(funder), type_to_string(tmpctx, struct pubkey, &peer->remote_per_commit), type_to_string(tmpctx, struct pubkey, &peer->old_remote_per_commit), peer->next_index[LOCAL], peer->next_index[REMOTE], peer->revocations_received, feerate_per_kw[LOCAL], feerate_per_kw[REMOTE], peer->feerate_min, peer->feerate_max); /* First commit is used for opening: if we've sent 0, we're on * index 1. */ assert(peer->next_index[LOCAL] > 0); assert(peer->next_index[REMOTE] > 0); /* channel_id is set from funding txout */ derive_channel_id(&peer->channel_id, &funding_txid, funding_txout); /* We derive everything from the one secret seed. */ derive_basepoints(&seed, &funding_pubkey[LOCAL], &points[LOCAL], &peer->our_secrets, &peer->shaseed); peer->channel = new_full_channel(peer, &funding_txid, funding_txout, funding_satoshi, local_msatoshi, feerate_per_kw, &peer->conf[LOCAL], &peer->conf[REMOTE], &points[LOCAL], &points[REMOTE], &funding_pubkey[LOCAL], &funding_pubkey[REMOTE], funder); if (!channel_force_htlcs(peer->channel, htlcs, hstates, fulfilled, fulfilled_sides, cast_const2(const struct failed_htlc **, failed), failed_sides)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not restore HTLCs"); /* We derive shared secrets for each remote HTLC, so we can * create error packet if necessary. */ init_shared_secrets(peer->channel, htlcs, hstates); peer->channel_direction = get_channel_direction( &peer->node_ids[LOCAL], &peer->node_ids[REMOTE]); /* Default desired feerate is the feerate we set for them last. */ if (peer->channel->funder == LOCAL) peer->desired_feerate = feerate_per_kw[REMOTE]; /* OK, now we can process peer messages. */ if (reconnected) peer_reconnect(peer); /* If we have a funding_signed message, send that immediately */ if (funding_signed) enqueue_peer_msg(peer, take(funding_signed)); billboard_update(peer); tal_free(msg); } static void send_shutdown_complete(struct peer *peer) { /* Push out any incomplete messages to peer. */ flush_peer_out(peer); /* Now we can tell master shutdown is complete. */ wire_sync_write(MASTER_FD, take(towire_channel_shutdown_complete(NULL, &peer->cs, peer->gossip_index))); fdpass_send(MASTER_FD, PEER_FD); fdpass_send(MASTER_FD, GOSSIP_FD); close(MASTER_FD); } int main(int argc, char *argv[]) { int i, nfds; fd_set fds_in, fds_out; struct peer *peer; subdaemon_setup(argc, argv); peer = tal(NULL, struct peer); peer->num_pings_outstanding = 0; timers_init(&peer->timers, time_mono()); peer->commit_timer = NULL; peer->have_sigs[LOCAL] = peer->have_sigs[REMOTE] = false; peer->announce_depth_reached = false; msg_queue_init(&peer->from_master, peer); msg_queue_init(&peer->from_gossipd, peer); msg_queue_init(&peer->peer_out, peer); peer->peer_outmsg = NULL; peer->peer_outoff = 0; peer->next_commit_sigs = NULL; peer->shutdown_sent[LOCAL] = false; peer->last_update_timestamp = 0; /* We send these to HSM to get real signatures; don't have valgrind * complain. */ for (i = 0; i < NUM_SIDES; i++) { memset(&peer->announcement_node_sigs[i], 0, sizeof(peer->announcement_node_sigs[i])); memset(&peer->announcement_bitcoin_sigs[i], 0, sizeof(peer->announcement_bitcoin_sigs[i])); } /* Read init_channel message sync. */ init_channel(peer); FD_ZERO(&fds_in); FD_SET(MASTER_FD, &fds_in); FD_SET(PEER_FD, &fds_in); FD_SET(GOSSIP_FD, &fds_in); FD_ZERO(&fds_out); FD_SET(PEER_FD, &fds_out); nfds = GOSSIP_FD+1; while (!shutdown_complete(peer)) { struct timemono first; fd_set rfds = fds_in, wfds, *wptr; struct timeval timeout, *tptr; struct timer *expired; const u8 *msg; struct timemono now = time_mono(); /* Free any temporary allocations */ clean_tmpctx(); /* For simplicity, we process one event at a time. */ msg = msg_dequeue(&peer->from_master); if (msg) { status_trace("Now dealing with deferred %s", channel_wire_type_name( fromwire_peektype(msg))); req_in(peer, msg); tal_free(msg); continue; } expired = timers_expire(&peer->timers, now); if (expired) { timer_expired(peer, expired); continue; } msg = msg_dequeue(&peer->from_gossipd); if (msg) { status_trace("Now dealing with deferred gossip %u", fromwire_peektype(msg)); gossip_in(peer, msg); tal_free(msg); continue; } if (timer_earliest(&peer->timers, &first)) { timeout = timespec_to_timeval( timemono_between(first, now).ts); tptr = &timeout; } else tptr = NULL; if (peer_write_pending(peer)) { wfds = fds_out; wptr = &wfds; } else wptr = NULL; if (select(nfds, &rfds, wptr, NULL, tptr) < 0) { /* Signals OK, eg. SIGUSR1 */ if (errno == EINTR) continue; status_failed(STATUS_FAIL_INTERNAL_ERROR, "select failed: %s", strerror(errno)); } /* Try writing out encrypted packet if any (don't block!) */ if (wptr && FD_ISSET(PEER_FD, wptr)) { if (!io_fd_block(PEER_FD, false)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "NONBLOCK failed: %s", strerror(errno)); do_peer_write(peer); if (!io_fd_block(PEER_FD, true)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "NONBLOCK unset failed: %s", strerror(errno)); continue; } if (FD_ISSET(MASTER_FD, &rfds)) { msg = wire_sync_read(peer, 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(GOSSIP_FD, &rfds)) { msg = wire_sync_read(peer, GOSSIP_FD); if (!msg) status_failed(STATUS_FAIL_GOSSIP_IO, "Can't read command: %s", strerror(errno)); gossip_in(peer, msg); } else if (FD_ISSET(PEER_FD, &rfds)) { /* This could take forever, but who cares? */ msg = channeld_read_peer_msg(peer); if (msg) peer_in(peer, msg); } else msg = NULL; tal_free(msg); } /* We only exit when shutdown is complete. */ assert(shutdown_complete(peer)); send_shutdown_complete(peer); tal_free(tmpctx); return 0; }