#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static bool state_update_ok(struct peer *peer, enum htlc_state oldstate, enum htlc_state newstate, u64 htlc_id, const char *dir) { enum htlc_state expected = oldstate + 1; /* We never get told about RCVD_REMOVE_HTLC, so skip over that * (we initialize in SENT_ADD_HTLC / RCVD_ADD_COMMIT, so those * work). */ if (expected == RCVD_REMOVE_HTLC) expected = RCVD_REMOVE_COMMIT; if (newstate != expected) { peer_internal_error(peer, "HTLC %s %"PRIu64" invalid update %s->%s", dir, htlc_id, htlc_state_name(oldstate), htlc_state_name(newstate)); return false; } log_debug(peer->log, "HTLC %s %"PRIu64" %s->%s", dir, htlc_id, htlc_state_name(oldstate), htlc_state_name(newstate)); return true; } static bool htlc_in_update_state(struct peer *peer, struct htlc_in *hin, enum htlc_state newstate) { if (!state_update_ok(peer, hin->hstate, newstate, hin->key.id, "in")) return false; wallet_htlc_update(peer->ld->wallet, hin->dbid, newstate, hin->preimage); hin->hstate = newstate; htlc_in_check(hin, __func__); return true; } static bool htlc_out_update_state(struct peer *peer, struct htlc_out *hout, enum htlc_state newstate) { if (!state_update_ok(peer, hout->hstate, newstate, hout->key.id, "out")) return false; wallet_htlc_update(peer->ld->wallet, hout->dbid, newstate, NULL); hout->hstate = newstate; htlc_out_check(hout, __func__); return true; } static void fail_in_htlc(struct htlc_in *hin, enum onion_type failcode, const u8 *failuremsg, const struct short_channel_id *out_channelid) { assert(!hin->preimage); assert(failcode || failuremsg); hin->failcode = failcode; if (failuremsg) hin->failuremsg = tal_dup_arr(hin, u8, failuremsg, tal_len(failuremsg), 0); /* We need this set, since we send it to channeld. */ if (hin->failcode & UPDATE) hin->failoutchannel = *out_channelid; else memset(&hin->failoutchannel, 0, sizeof(hin->failoutchannel)); /* We update state now to signal it's in progress, for persistence. */ htlc_in_update_state(hin->key.peer, hin, SENT_REMOVE_HTLC); /* Tell peer, if we can. */ if (!hin->key.peer->owner) return; subd_send_msg(hin->key.peer->owner, take(towire_channel_fail_htlc(hin, hin->key.id, hin->failuremsg, hin->failcode, &hin->failoutchannel))); } /* This is used for cases where we can immediately fail the HTLC. */ static void local_fail_htlc(struct htlc_in *hin, enum onion_type failcode, const struct short_channel_id *out_channel) { log_info(hin->key.peer->log, "failed htlc %"PRIu64" code 0x%04x (%s)", hin->key.id, failcode, onion_type_name(failcode)); fail_in_htlc(hin, failcode, NULL, out_channel); } /* localfail are for handing to the local payer if it's local. */ static void fail_out_htlc(struct htlc_out *hout, const char *localfail) { htlc_out_check(hout, __func__); assert(hout->failcode || hout->failuremsg); if (hout->in) { fail_in_htlc(hout->in, hout->failcode, hout->failuremsg, hout->key.peer->scid); } else { payment_failed(hout->key.peer->ld, hout, localfail); } } /* BOLT #4: * * * `amt_to_forward` - The amount in milli-satoshi to forward to the next * (outgoing) hop specified within the routing information. * * This value MUST factor in the computed fee for this particular hop. When * processing an incoming Sphinx packet along with the HTLC message it's * encapsulated within, if the following inequality doesn't hold, then the * HTLC should be rejected as it indicates a prior node in the path has * deviated from the specified parameters: * * incoming_htlc_amt - fee >= amt_to_forward * * Where `fee` is calculated according to the receiving node's advertised fee * schema as described in [BOLT 7](https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#htlc-fees), or 0 if this node is the * final hop. */ static bool check_amount(struct htlc_in *hin, u64 amt_to_forward, u64 amt_in_htlc, u64 fee) { if (amt_in_htlc - fee >= amt_to_forward) return true; log_debug(hin->key.peer->ld->log, "HTLC %"PRIu64" incorrect amount:" " %"PRIu64" in, %"PRIu64" out, fee reqd %"PRIu64, hin->key.id, amt_in_htlc, amt_to_forward, fee); return false; } /* BOLT #4: * * * `outgoing_cltv_value` - The CLTV value that the _outgoing_ HTLC carrying * the packet should have. * * cltv_expiry - cltv_expiry_delta >= outgoing_cltv_value * * Inclusion of this field allows a node to both authenticate the information * specified by the original sender and the parameters of the HTLC forwarded, * and ensure the original sender is using the current `cltv_expiry_delta` value. * If there is no next hop, `cltv_expiry_delta` is zero. * If the values don't correspond, then the HTLC should be failed+rejected as * this indicates the incoming node has tampered with the intended HTLC * values, or the origin has an obsolete `cltv_expiry_delta` value. * The node MUST be consistent in responding to an unexpected * `outgoing_cltv_value` whether it is the final hop or not, to avoid * leaking that information. */ static bool check_cltv(struct htlc_in *hin, u32 cltv_expiry, u32 outgoing_cltv_value, u32 delta) { if (cltv_expiry - delta >= outgoing_cltv_value) return true; log_debug(hin->key.peer->ld->log, "HTLC %"PRIu64" incorrect CLTV:" " %u in, %u out, delta reqd %u", hin->key.id, cltv_expiry, outgoing_cltv_value, delta); return false; } static void fulfill_htlc(struct htlc_in *hin, const struct preimage *preimage) { u8 *msg; hin->preimage = tal_dup(hin, struct preimage, preimage); htlc_in_check(hin, __func__); /* We update state now to signal it's in progress, for persistence. */ htlc_in_update_state(hin->key.peer, hin, SENT_REMOVE_HTLC); /* No owner? We'll either send to channeld in peer_htlcs, or * onchaind in onchaind_tell_fulfill. */ if (!hin->key.peer->owner) { log_debug(hin->key.peer->log, "HTLC fulfilled, but no owner."); return; } if (peer_state_on_chain(hin->key.peer->state)) { msg = towire_onchain_known_preimage(hin, preimage); } else { msg = towire_channel_fulfill_htlc(hin, hin->key.id, preimage); } subd_send_msg(hin->key.peer->owner, take(msg)); } static void handle_localpay(struct htlc_in *hin, u32 cltv_expiry, const struct sha256 *payment_hash, u64 amt_to_forward, u32 outgoing_cltv_value) { enum onion_type failcode; const struct invoice *invoice; struct lightningd *ld = hin->key.peer->ld; /* BOLT #4: * * If the `amt_to_forward` is higher than `incoming_htlc_amt` of * the HTLC at the final hop: * * 1. type: 19 (`final_incorrect_htlc_amount`) * 2. data: * * [`4`:`incoming_htlc_amt`] */ if (!check_amount(hin, amt_to_forward, hin->msatoshi, 0)) { failcode = WIRE_FINAL_INCORRECT_HTLC_AMOUNT; goto fail; } /* BOLT #4: * * If the `outgoing_cltv_value` does not match the `cltv_expiry` of * the HTLC at the final hop: * * 1. type: 18 (`final_incorrect_cltv_expiry`) * 2. data: * * [`4`:`cltv_expiry`] */ if (!check_cltv(hin, cltv_expiry, outgoing_cltv_value, 0)) { failcode = WIRE_FINAL_INCORRECT_CLTV_EXPIRY; goto fail; } invoice = wallet_invoice_find_unpaid(ld->wallet, payment_hash); if (!invoice) { failcode = WIRE_UNKNOWN_PAYMENT_HASH; goto fail; } /* BOLT #4: * * If the amount paid is less than the amount expected, the final node * MUST fail the HTLC. If the amount paid is more than twice the * amount expected, the final node SHOULD fail the HTLC. This allows * the sender to reduce information leakage by altering the amount, * without allowing accidental gross overpayment: * * 1. type: PERM|16 (`incorrect_payment_amount`) */ if (invoice->msatoshi != NULL && hin->msatoshi < *invoice->msatoshi) { failcode = WIRE_INCORRECT_PAYMENT_AMOUNT; goto fail; } else if (invoice->msatoshi != NULL && hin->msatoshi > *invoice->msatoshi * 2) { failcode = WIRE_INCORRECT_PAYMENT_AMOUNT; goto fail; } /* BOLT #4: * * If the `cltv_expiry` is too low, the final node MUST fail the HTLC: */ if (get_block_height(ld->topology) + ld->config.cltv_final > cltv_expiry) { log_debug(hin->key.peer->log, "Expiry cltv too soon %u < %u + %u", cltv_expiry, get_block_height(ld->topology), ld->config.cltv_final); failcode = WIRE_FINAL_EXPIRY_TOO_SOON; goto fail; } log_info(ld->log, "Resolving invoice '%s' with HTLC %"PRIu64, invoice->label, hin->key.id); log_debug(ld->log, "%s: Actual amount %"PRIu64"msat, HTLC expiry %u", invoice->label, hin->msatoshi, cltv_expiry); fulfill_htlc(hin, &invoice->r); wallet_invoice_resolve(ld->wallet, invoice, hin->msatoshi); return; fail: /* Final hop never sends an UPDATE. */ assert(!(failcode & UPDATE)); local_fail_htlc(hin, failcode, NULL); } /* * A catchall in case outgoing peer disconnects before getting fwd. * * We could queue this and wait for it to come back, but this is simple. */ static void hout_subd_died(struct htlc_out *hout) { log_debug(hout->key.peer->log, "Failing HTLC %"PRIu64" due to peer death", hout->key.id); hout->failcode = WIRE_TEMPORARY_CHANNEL_FAILURE; fail_out_htlc(hout, "Outgoing subdaemon died"); } /* This is where channeld gives us the HTLC id, and also reports if it * failed immediately. */ static void rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds, struct htlc_out *hout) { u16 failure_code; u8 *failurestr; if (!fromwire_channel_offer_htlc_reply(msg, msg, NULL, &hout->key.id, &failure_code, &failurestr)) { peer_internal_error(subd->peer, "Bad channel_offer_htlc_reply"); tal_free(hout); return; } if (failure_code) { hout->failcode = (enum onion_type) failure_code; if (!hout->in) { char *localfail = tal_fmt(msg, "%s: %.*s", onion_type_name(failure_code), (int)tal_len(failurestr), (const char *)failurestr); payment_failed(hout->key.peer->ld, hout, localfail); } else local_fail_htlc(hout->in, failure_code, hout->key.peer->scid); /* Prevent hout from being failed twice. */ tal_del_destructor(hout, hout_subd_died); tal_free(hout); return; } if (find_htlc_out(&subd->ld->htlcs_out, hout->key.peer, hout->key.id) || hout->key.id == HTLC_INVALID_ID) { peer_internal_error(subd->peer, "Bad offer_htlc_reply HTLC id %"PRIu64 " is a duplicate", hout->key.id); tal_free(hout); return; } /* Add it to lookup table now we know id. */ connect_htlc_out(&subd->ld->htlcs_out, hout); /* When channeld includes it in commitment, we'll make it persistent. */ } enum onion_type send_htlc_out(struct peer *out, u64 amount, u32 cltv, const struct sha256 *payment_hash, const u8 *onion_routing_packet, struct htlc_in *in, struct command *cmd, struct htlc_out **houtp) { struct htlc_out *hout; u8 *msg; if (!peer_can_add_htlc(out)) { log_info(out->log, "Attempt to send HTLC but not ready (%s)", peer_state_name(out->state)); return WIRE_UNKNOWN_NEXT_PEER; } if (!out->owner) { log_info(out->log, "Attempt to send HTLC but unowned (%s)", peer_state_name(out->state)); return WIRE_TEMPORARY_CHANNEL_FAILURE; } /* Make peer's daemon own it, catch if it dies. */ hout = new_htlc_out(out->owner, out, amount, cltv, payment_hash, onion_routing_packet, in, cmd); tal_add_destructor(hout, hout_subd_died); msg = towire_channel_offer_htlc(out, amount, cltv, payment_hash, onion_routing_packet); subd_req(out->ld, out->owner, take(msg), -1, 0, rcvd_htlc_reply, hout); if (houtp) *houtp = hout; return 0; } static void forward_htlc(struct htlc_in *hin, u32 cltv_expiry, const struct sha256 *payment_hash, u64 amt_to_forward, u32 outgoing_cltv_value, const struct pubkey *next_hop, const u8 next_onion[TOTAL_PACKET_SIZE]) { enum onion_type failcode; u64 fee; struct lightningd *ld = hin->key.peer->ld; struct peer *next = peer_by_id(ld, next_hop); /* Unknown peer, or peer not ready. */ if (!next || !next->scid) { local_fail_htlc(hin, WIRE_UNKNOWN_NEXT_PEER, NULL); return; } /* BOLT #7: * * The node creating `channel_update` SHOULD accept HTLCs which pay a * fee equal or greater than: * * fee_base_msat + amount_msat * fee_proportional_millionths / 1000000 */ if (mul_overflows_u64(amt_to_forward, ld->config.fee_per_satoshi)) { failcode = WIRE_FEE_INSUFFICIENT; goto fail; } fee = ld->config.fee_base + amt_to_forward * ld->config.fee_per_satoshi / 1000000; if (!check_amount(hin, amt_to_forward, hin->msatoshi, fee)) { failcode = WIRE_FEE_INSUFFICIENT; goto fail; } if (!check_cltv(hin, cltv_expiry, outgoing_cltv_value, ld->config.cltv_expiry_delta)) { failcode = WIRE_INCORRECT_CLTV_EXPIRY; goto fail; } /* BOLT #2: * * A node MUST estimate a timeout deadline for each HTLC it offers. A * node MUST NOT offer an HTLC with a timeout deadline before its * `cltv_expiry` */ /* In our case, G = 1, so we need to expire it one after it's expiration. * But never offer an expired HTLC; that's dumb. */ if (get_block_height(next->ld->topology) >= outgoing_cltv_value) { log_debug(hin->key.peer->log, "Expiry cltv %u too close to current %u", outgoing_cltv_value, get_block_height(next->ld->topology)); failcode = WIRE_EXPIRY_TOO_SOON; goto fail; } /* BOLT #4: * * If the `cltv_expiry` is unreasonably far, we can also report an error: * * 1. type: 21 (`expiry_too_far`) */ if (get_block_height(next->ld->topology) + next->ld->config.max_htlc_expiry < outgoing_cltv_value) { log_debug(hin->key.peer->log, "Expiry cltv %u too far from current %u + max %u", outgoing_cltv_value, get_block_height(next->ld->topology), next->ld->config.max_htlc_expiry); failcode = WIRE_EXPIRY_TOO_FAR; goto fail; } failcode = send_htlc_out(next, amt_to_forward, outgoing_cltv_value, &hin->payment_hash, next_onion, hin, NULL, NULL); if (!failcode) return; fail: local_fail_htlc(hin, failcode, next->scid); } /* Temporary information, while we resolve the next hop */ struct gossip_resolve { struct short_channel_id next_channel; u64 amt_to_forward; u32 outgoing_cltv_value; u8 *next_onion; struct htlc_in *hin; }; /* We received a resolver reply, which gives us the node_ids of the * channel we want to forward over */ static void channel_resolve_reply(struct subd *gossip, const u8 *msg, const int *fds, struct gossip_resolve *gr) { struct pubkey *nodes, *peer_id; if (!fromwire_gossip_resolve_channel_reply(msg, msg, NULL, &nodes)) { log_broken(gossip->log, "bad fromwire_gossip_resolve_channel_reply %s", tal_hex(msg, msg)); return; } if (tal_count(nodes) == 0) { local_fail_htlc(gr->hin, WIRE_UNKNOWN_NEXT_PEER, NULL); return; } else if (tal_count(nodes) != 2) { log_broken(gossip->log, "fromwire_gossip_resolve_channel_reply has %zu nodes", tal_count(nodes)); return; } /* Get the other peer matching the id that is not us */ if (pubkey_cmp(&nodes[0], &gossip->ld->id) == 0) { peer_id = &nodes[1]; } else { peer_id = &nodes[0]; } forward_htlc(gr->hin, gr->hin->cltv_expiry, &gr->hin->payment_hash, gr->amt_to_forward, gr->outgoing_cltv_value, peer_id, gr->next_onion); tal_free(gr); } /* Everyone is committed to this htlc of theirs */ static bool peer_accepted_htlc(struct peer *peer, u64 id, enum onion_type *failcode) { struct htlc_in *hin; u8 *req; struct route_step *rs; struct onionpacket *op; const tal_t *tmpctx = tal_tmpctx(peer); hin = find_htlc_in(&peer->ld->htlcs_in, peer, id); if (!hin) { peer_internal_error(peer, "peer_got_revoke unknown htlc %"PRIu64, id); return false; } if (!htlc_in_update_state(peer, hin, RCVD_ADD_ACK_REVOCATION)) return false; /* BOLT #2: * * A sending node SHOULD fail to route any HTLC added after it * sent `shutdown`. */ if (peer->state == CHANNELD_SHUTTING_DOWN) { *failcode = WIRE_PERMANENT_CHANNEL_FAILURE; goto out; } /* BOLT #2: * * A node MUST estimate a fulfillment deadline for each HTLC it is * attempting to fulfill. A node MUST fail (and not forward) an HTLC * whose fulfillment deadline is already past */ /* Our deadline is half the cltv_delta we insist on, so this check is * a subset of the cltv check done in handle_localpay and * forward_htlc. */ /* channeld tests this, so it should have set ss to zeroes. */ op = parse_onionpacket(tmpctx, hin->onion_routing_packet, sizeof(hin->onion_routing_packet)); if (!op) { if (!memeqzero(&hin->shared_secret, sizeof(hin->shared_secret))){ peer_internal_error(peer, "bad onion in got_revoke: %s", tal_hexstr(peer, hin->onion_routing_packet, sizeof(hin->onion_routing_packet))); tal_free(tmpctx); return false; } /* FIXME: could be bad version, bad key. */ *failcode = WIRE_INVALID_ONION_VERSION; goto out; } /* Channeld sets this to zero if HSM won't ecdh it */ if (memeqzero(&hin->shared_secret, sizeof(hin->shared_secret))) { *failcode = WIRE_INVALID_ONION_KEY; goto out; } /* If it's crap, not channeld's fault, just fail it */ rs = process_onionpacket(tmpctx, op, hin->shared_secret.data, hin->payment_hash.u.u8, sizeof(hin->payment_hash)); if (!rs) { *failcode = WIRE_INVALID_ONION_HMAC; goto out; } /* Unknown realm isn't a bad onion, it's a normal failure. */ if (rs->hop_data.realm != 0) { *failcode = WIRE_INVALID_REALM; goto out; } if (rs->nextcase == ONION_FORWARD) { struct gossip_resolve *gr = tal(peer->ld, struct gossip_resolve); gr->next_onion = serialize_onionpacket(gr, rs->next); gr->next_channel = rs->hop_data.channel_id; gr->amt_to_forward = rs->hop_data.amt_forward; gr->outgoing_cltv_value = rs->hop_data.outgoing_cltv; gr->hin = hin; req = towire_gossip_resolve_channel_request(tmpctx, &gr->next_channel); log_debug(peer->log, "Asking gossip to resolve channel %s", type_to_string(tmpctx, struct short_channel_id, &gr->next_channel)); subd_req(hin, peer->ld->gossip, req, -1, 0, channel_resolve_reply, gr); } else handle_localpay(hin, hin->cltv_expiry, &hin->payment_hash, rs->hop_data.amt_forward, rs->hop_data.outgoing_cltv); *failcode = 0; out: log_debug(peer->log, "their htlc %"PRIu64" %s", id, *failcode ? onion_type_name(*failcode) : "locked"); tal_free(tmpctx); return true; } static void fulfill_our_htlc_out(struct peer *peer, struct htlc_out *hout, const struct preimage *preimage) { assert(!hout->preimage); hout->preimage = tal_dup(hout, struct preimage, preimage); htlc_out_check(hout, __func__); wallet_htlc_update(peer->ld->wallet, hout->dbid, hout->hstate, preimage); if (hout->in) fulfill_htlc(hout->in, preimage); else payment_succeeded(peer->ld, hout, preimage); } static bool peer_fulfilled_our_htlc(struct peer *peer, const struct fulfilled_htlc *fulfilled) { struct htlc_out *hout; hout = find_htlc_out(&peer->ld->htlcs_out, peer, fulfilled->id); if (!hout) { peer_internal_error(peer, "fulfilled_our_htlc unknown htlc %"PRIu64, fulfilled->id); return false; } if (!htlc_out_update_state(peer, hout, RCVD_REMOVE_COMMIT)) return false; fulfill_our_htlc_out(peer, hout, &fulfilled->payment_preimage); return true; } void onchain_fulfilled_htlc(struct peer *peer, const struct preimage *preimage) { struct htlc_out_map_iter outi; struct htlc_out *hout; struct sha256 payment_hash; sha256(&payment_hash, preimage, sizeof(*preimage)); /* FIXME: use db to look this up! */ for (hout = htlc_out_map_first(&peer->ld->htlcs_out, &outi); hout; hout = htlc_out_map_next(&peer->ld->htlcs_out, &outi)) { if (hout->key.peer != peer) continue; if (!structeq(&hout->payment_hash, &payment_hash)) continue; /* We may have already fulfilled before going onchain, or * we can fulfill onchain multiple times. */ if (!hout->preimage) fulfill_our_htlc_out(peer, hout, preimage); /* We keep going: this is something of a leak, but onchain * we have no real way of distinguishing HTLCs anyway */ } } static bool peer_failed_our_htlc(struct peer *peer, const struct failed_htlc *failed) { struct htlc_out *hout; hout = find_htlc_out(&peer->ld->htlcs_out, peer, failed->id); if (!hout) { peer_internal_error(peer, "failed_our_htlc unknown htlc %"PRIu64, failed->id); return false; } if (!htlc_out_update_state(peer, hout, RCVD_REMOVE_COMMIT)) return false; hout->failcode = failed->malformed; if (!failed->malformed) hout->failuremsg = tal_dup_arr(hout, u8, failed->failreason, tal_len(failed->failreason), 0); else hout->failuremsg = NULL; log_debug(peer->log, "Our HTLC %"PRIu64" failed (%u)", failed->id, hout->failcode); htlc_out_check(hout, __func__); return true; } /* FIXME: Crazy slow! */ struct htlc_out *find_htlc_out_by_ripemd(const struct peer *peer, const struct ripemd160 *ripemd) { struct htlc_out_map_iter outi; struct htlc_out *hout; for (hout = htlc_out_map_first(&peer->ld->htlcs_out, &outi); hout; hout = htlc_out_map_next(&peer->ld->htlcs_out, &outi)) { struct ripemd160 hash; if (hout->key.peer != peer) continue; ripemd160(&hash, &hout->payment_hash, sizeof(hout->payment_hash)); if (structeq(&hash, ripemd)) return hout; } return NULL; } void onchain_failed_our_htlc(const struct peer *peer, const struct htlc_stub *htlc, const char *why) { struct htlc_out *hout = find_htlc_out_by_ripemd(peer, &htlc->ripemd); /* Don't fail twice! */ if (hout->failuremsg || hout->failcode) return; hout->failcode = WIRE_PERMANENT_CHANNEL_FAILURE; if (!hout->in) { char *localfail = tal_fmt(peer, "%s: %s", onion_type_name(WIRE_PERMANENT_CHANNEL_FAILURE), why); payment_failed(hout->key.peer->ld, hout, localfail); tal_free(localfail); } else local_fail_htlc(hout->in, WIRE_PERMANENT_CHANNEL_FAILURE, hout->key.peer->scid); } static void remove_htlc_in(struct peer *peer, struct htlc_in *hin) { htlc_in_check(hin, __func__); assert(hin->failuremsg || hin->preimage || hin->failcode); log_debug(peer->log, "Removing in HTLC %"PRIu64" state %s %s", hin->key.id, htlc_state_name(hin->hstate), hin->preimage ? "FULFILLED" : hin->failcode ? onion_type_name(hin->failcode) : "REMOTEFAIL"); /* If we fulfilled their HTLC, credit us. */ if (hin->preimage) { log_debug(peer->log, "Balance %"PRIu64" -> %"PRIu64, *peer->our_msatoshi, *peer->our_msatoshi + hin->msatoshi); *peer->our_msatoshi += hin->msatoshi; } tal_free(hin); } static void remove_htlc_out(struct peer *peer, struct htlc_out *hout) { htlc_out_check(hout, __func__); assert(hout->failuremsg || hout->preimage || hout->failcode); log_debug(peer->log, "Removing out HTLC %"PRIu64" state %s %s", hout->key.id, htlc_state_name(hout->hstate), hout->preimage ? "FULFILLED" : hout->failcode ? onion_type_name(hout->failcode) : "REMOTEFAIL"); /* If it's failed, now we can forward since it's completely locked-in */ if (!hout->preimage) { fail_out_htlc(hout, NULL); } else { /* We paid for this HTLC, so deduct balance. */ log_debug(peer->log, "Balance %"PRIu64" -> %"PRIu64, *peer->our_msatoshi, *peer->our_msatoshi - hout->msatoshi); *peer->our_msatoshi -= hout->msatoshi; } tal_free(hout); } static bool update_in_htlc(struct peer *peer, u64 id, enum htlc_state newstate) { struct htlc_in *hin; hin = find_htlc_in(&peer->ld->htlcs_in, peer, id); if (!hin) { peer_internal_error(peer, "Can't find in HTLC %"PRIu64, id); return false; } if (!htlc_in_update_state(peer, hin, newstate)) return false; if (newstate == SENT_REMOVE_ACK_REVOCATION) remove_htlc_in(peer, hin); return true; } static bool update_out_htlc(struct peer *peer, u64 id, enum htlc_state newstate) { struct htlc_out *hout; hout = find_htlc_out(&peer->ld->htlcs_out, peer, id); if (!hout) { peer_internal_error(peer, "Can't find out HTLC %"PRIu64, id); return false; } if (!hout->dbid) { wallet_htlc_save_out(peer->ld->wallet, peer->channel, hout); /* For our own HTLCs, we commit payment to db lazily */ if (hout->origin_htlc_id == 0) wallet_payment_store(peer->ld->wallet, &hout->payment_hash); } if (!htlc_out_update_state(peer, hout, newstate)) return false; /* First transition into commitment; now it outlives peer. */ if (newstate == SENT_ADD_COMMIT) { tal_del_destructor(hout, hout_subd_died); tal_steal(peer->ld, hout); } else if (newstate == RCVD_REMOVE_ACK_REVOCATION) { remove_htlc_out(peer, hout); } return true; } static bool changed_htlc(struct peer *peer, const struct changed_htlc *changed) { if (htlc_state_owner(changed->newstate) == LOCAL) return update_out_htlc(peer, changed->id, changed->newstate); else return update_in_htlc(peer, changed->id, changed->newstate); } static bool peer_save_commitsig_received(struct peer *peer, u64 commitnum, struct bitcoin_tx *tx, const secp256k1_ecdsa_signature *commit_sig) { if (commitnum != peer->next_index[LOCAL]) { peer_internal_error(peer, "channel_got_commitsig: expected commitnum %"PRIu64 " got %"PRIu64, peer->next_index[LOCAL], commitnum); return false; } peer->next_index[LOCAL]++; /* Update peer->last_sig and peer->last_tx before saving to db */ peer_last_tx(peer, tx, commit_sig); return true; } static bool peer_save_commitsig_sent(struct peer *peer, u64 commitnum) { if (commitnum != peer->next_index[REMOTE]) { peer_internal_error(peer, "channel_sent_commitsig: expected commitnum %"PRIu64 " got %"PRIu64, peer->next_index[REMOTE], commitnum); return false; } peer->next_index[REMOTE]++; /* FIXME: Save to database, with sig and HTLCs. */ wallet_channel_save(peer->ld->wallet, peer->channel, 0); return true; } void peer_sending_commitsig(struct peer *peer, const u8 *msg) { u64 commitnum; u32 feerate; struct changed_htlc *changed_htlcs; size_t i, maxid = 0, num_local_added = 0; secp256k1_ecdsa_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; if (!fromwire_channel_sending_commitsig(msg, msg, NULL, &commitnum, &feerate, &changed_htlcs, &commit_sig, &htlc_sigs)) { peer_internal_error(peer, "bad channel_sending_commitsig %s", tal_hex(peer, msg)); return; } for (i = 0; i < tal_count(changed_htlcs); i++) { if (!changed_htlc(peer, changed_htlcs + i)) { peer_internal_error(peer, "channel_sending_commitsig: update failed"); return; } /* While we're here, sanity check added ones are in * ascending order. */ if (changed_htlcs[i].newstate == SENT_ADD_COMMIT) { num_local_added++; if (changed_htlcs[i].id > maxid) maxid = changed_htlcs[i].id; } } if (num_local_added != 0) { if (maxid != peer->next_htlc_id + num_local_added - 1) { peer_internal_error(peer, "channel_sending_commitsig:" " Added %"PRIu64", maxid now %"PRIu64 " from %"PRIu64, num_local_added, maxid, peer->next_htlc_id); return; } peer->next_htlc_id += num_local_added; } /* Update their feerate. */ peer->channel_info->feerate_per_kw[REMOTE] = feerate; if (!peer_save_commitsig_sent(peer, commitnum)) return; /* Last was commit. */ peer->last_was_revoke = false; tal_free(peer->last_sent_commit); peer->last_sent_commit = tal_steal(peer, changed_htlcs); wallet_channel_save(peer->ld->wallet, peer->channel, 0); /* Tell it we've got it, and to go ahead with commitment_signed. */ subd_send_msg(peer->owner, take(towire_channel_sending_commitsig_reply(msg))); } static bool peer_added_their_htlc(struct peer *peer, const struct added_htlc *added, const struct secret *shared_secret) { struct htlc_in *hin; /* BOLT #2: * * - receiving an `amount_msat` equal to 0, OR less than its own `htlc_minimum_msat`: * - SHOULD fail the channel. */ if (added->amount_msat == 0 || added->amount_msat < peer->our_config.htlc_minimum_msat) { peer_internal_error(peer, "trying to add HTLC msat %"PRIu64 " but minimum is %"PRIu64, added->amount_msat, peer->our_config.htlc_minimum_msat); return false; } /* This stays around even if we fail it immediately: it *is* * part of the current commitment. */ hin = new_htlc_in(peer, peer, added->id, added->amount_msat, added->cltv_expiry, &added->payment_hash, shared_secret, added->onion_routing_packet); /* Save an incoming htlc to the wallet */ wallet_htlc_save_in(peer->ld->wallet, peer->channel, hin); log_debug(peer->log, "Adding their HTLC %"PRIu64, added->id); connect_htlc_in(&peer->ld->htlcs_in, hin); return true; } /* The peer doesn't tell us this separately, but logically it's a separate * step to receiving commitsig */ static bool peer_sending_revocation(struct peer *peer, struct added_htlc *added, struct fulfilled_htlc *fulfilled, struct failed_htlc *failed, struct changed_htlc *changed) { size_t i; for (i = 0; i < tal_count(added); i++) { if (!update_in_htlc(peer, added[i].id, SENT_ADD_REVOCATION)) return false; } for (i = 0; i < tal_count(fulfilled); i++) { if (!update_out_htlc(peer, fulfilled[i].id, SENT_REMOVE_REVOCATION)) return false; } for (i = 0; i < tal_count(failed); i++) { if (!update_out_htlc(peer, failed[i].id, SENT_REMOVE_REVOCATION)) return false; } for (i = 0; i < tal_count(changed); i++) { if (changed[i].newstate == RCVD_ADD_ACK_COMMIT) { if (!update_out_htlc(peer, changed[i].id, SENT_ADD_ACK_REVOCATION)) return false; } else { if (!update_in_htlc(peer, changed[i].id, SENT_REMOVE_ACK_REVOCATION)) return false; } } peer->last_was_revoke = true; return true; } /* This also implies we're sending revocation */ void peer_got_commitsig(struct peer *peer, const u8 *msg) { u64 commitnum; u32 feerate; secp256k1_ecdsa_signature commit_sig; secp256k1_ecdsa_signature *htlc_sigs; struct added_htlc *added; struct secret *shared_secrets; struct fulfilled_htlc *fulfilled; struct failed_htlc *failed; struct changed_htlc *changed; struct bitcoin_tx *tx = tal(msg, struct bitcoin_tx); size_t i; if (!fromwire_channel_got_commitsig(msg, msg, NULL, &commitnum, &feerate, &commit_sig, &htlc_sigs, &added, &shared_secrets, &fulfilled, &failed, &changed, tx)) { peer_internal_error(peer, "bad fromwire_channel_got_commitsig %s", tal_hex(peer, msg)); return; } log_debug(peer->log, "got commitsig %"PRIu64 ": feerate %u, %zu added, %zu fulfilled, %zu failed, %zu changed", commitnum, feerate, tal_count(added), tal_count(fulfilled), tal_count(failed), tal_count(changed)); /* New HTLCs */ for (i = 0; i < tal_count(added); i++) { if (!peer_added_their_htlc(peer, &added[i], &shared_secrets[i])) return; } /* Save information now for fulfilled & failed HTLCs */ for (i = 0; i < tal_count(fulfilled); i++) { if (!peer_fulfilled_our_htlc(peer, &fulfilled[i])) return; } for (i = 0; i < tal_count(failed); i++) { if (!peer_failed_our_htlc(peer, &failed[i])) return; } for (i = 0; i < tal_count(changed); i++) { if (!changed_htlc(peer, &changed[i])) { peer_internal_error(peer, "got_commitsig: update failed"); return; } } /* Update both feerates: if we're funder, REMOTE should already be * that feerate, if we're not, we're about to ACK anyway. */ peer->channel_info->feerate_per_kw[LOCAL] = peer->channel_info->feerate_per_kw[REMOTE] = feerate; /* Since we're about to send revoke, bump state again. */ if (!peer_sending_revocation(peer, added, fulfilled, failed, changed)) return; if (!peer_save_commitsig_received(peer, commitnum, tx, &commit_sig)) return; wallet_channel_save(peer->ld->wallet, peer->channel, 0); /* FIXME: Put these straight in the db! */ tal_free(peer->last_htlc_sigs); peer->last_htlc_sigs = tal_steal(peer, htlc_sigs); /* Tell it we've committed, and to go ahead with revoke. */ msg = towire_channel_got_commitsig_reply(msg); subd_send_msg(peer->owner, take(msg)); } /* Shuffle them over, forgetting the ancient one. */ void update_per_commit_point(struct peer *peer, const struct pubkey *per_commitment_point) { struct channel_info *ci = peer->channel_info; ci->old_remote_per_commit = ci->remote_per_commit; ci->remote_per_commit = *per_commitment_point; } void peer_got_revoke(struct peer *peer, const u8 *msg) { u64 revokenum; struct sha256 per_commitment_secret; struct pubkey next_per_commitment_point; struct changed_htlc *changed; enum onion_type *failcodes; size_t i; if (!fromwire_channel_got_revoke(msg, msg, NULL, &revokenum, &per_commitment_secret, &next_per_commitment_point, &changed)) { peer_internal_error(peer, "bad fromwire_channel_got_revoke %s", tal_hex(peer, msg)); return; } log_debug(peer->log, "got revoke %"PRIu64": %zu changed", revokenum, tal_count(changed)); /* Save any immediate failures for after we reply. */ failcodes = tal_arrz(msg, enum onion_type, tal_count(changed)); for (i = 0; i < tal_count(changed); i++) { /* If we're doing final accept, we need to forward */ if (changed[i].newstate == RCVD_ADD_ACK_REVOCATION) { if (!peer_accepted_htlc(peer, changed[i].id, &failcodes[i])) return; } else { if (!changed_htlc(peer, &changed[i])) { peer_internal_error(peer, "got_revoke: update failed"); return; } } } if (revokenum >= (1ULL << 48)) { peer_internal_error(peer, "got_revoke: too many txs %"PRIu64, revokenum); return; } if (revokenum != revocations_received(&peer->their_shachain.chain)) { peer_internal_error(peer, "got_revoke: expected %"PRIu64 " got %"PRIu64, revocations_received(&peer->their_shachain.chain), revokenum); return; } /* BOLT #2: * * A receiving node MAY fail if the `per_commitment_secret` was not * generated by the protocol in [BOLT #3] */ if (!wallet_shachain_add_hash(peer->ld->wallet, &peer->their_shachain, shachain_index(revokenum), &per_commitment_secret)) { peer_fail_permanent(peer, "Bad per_commitment_secret %s for %"PRIu64, type_to_string(msg, struct sha256, &per_commitment_secret), revokenum); return; } /* FIXME: Check per_commitment_secret -> per_commit_point */ update_per_commit_point(peer, &next_per_commitment_point); /* Tell it we've committed, and to go ahead with revoke. */ msg = towire_channel_got_revoke_reply(msg); subd_send_msg(peer->owner, take(msg)); /* Now, any HTLCs we need to immediately fail? */ for (i = 0; i < tal_count(changed); i++) { struct htlc_in *hin; if (!failcodes[i]) continue; /* These are all errors before finding next hop. */ assert(!(failcodes[i] & UPDATE)); hin = find_htlc_in(&peer->ld->htlcs_in, peer, changed[i].id); local_fail_htlc(hin, failcodes[i], NULL); } wallet_channel_save(peer->ld->wallet, peer->channel, 0); } 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 add_htlc(struct added_htlc **htlcs, enum htlc_state **htlc_states, u64 id, u64 amount_msat, const struct sha256 *payment_hash, u32 cltv_expiry, const u8 onion_routing_packet[TOTAL_PACKET_SIZE], enum htlc_state state) { struct added_htlc *a; enum htlc_state *h; a = tal_arr_append(htlcs); h = tal_arr_append(htlc_states); a->id = id; a->amount_msat = amount_msat; a->payment_hash = *payment_hash; a->cltv_expiry = cltv_expiry; memcpy(a->onion_routing_packet, onion_routing_packet, sizeof(a->onion_routing_packet)); *h = state; } static void add_fulfill(u64 id, enum side side, const struct preimage *payment_preimage, struct fulfilled_htlc **fulfilled_htlcs, enum side **fulfilled_sides) { struct fulfilled_htlc *f; enum side *s; f = tal_arr_append(fulfilled_htlcs); s = tal_arr_append(fulfilled_sides); f->id = id; f->payment_preimage = *payment_preimage; *s = side; } static void add_fail(u64 id, enum side side, const u8 *failuremsg, struct failed_htlc **failed_htlcs, enum side **failed_sides) { struct failed_htlc *f; enum side *s; f = tal_arr_append(failed_htlcs); s = tal_arr_append(failed_sides); f->id = id; f->failreason = tal_dup_arr(*failed_htlcs, u8, failuremsg, tal_len(failuremsg), 0); *s = side; } /* FIXME: Load direct from db. */ void peer_htlcs(const tal_t *ctx, const struct peer *peer, struct added_htlc **htlcs, enum htlc_state **htlc_states, struct fulfilled_htlc **fulfilled_htlcs, enum side **fulfilled_sides, struct failed_htlc **failed_htlcs, enum side **failed_sides) { struct htlc_in_map_iter ini; struct htlc_out_map_iter outi; struct htlc_in *hin; struct htlc_out *hout; *htlcs = tal_arr(ctx, struct added_htlc, 0); *htlc_states = tal_arr(ctx, enum htlc_state, 0); *fulfilled_htlcs = tal_arr(ctx, struct fulfilled_htlc, 0); *fulfilled_sides = tal_arr(ctx, enum side, 0); *failed_htlcs = tal_arr(ctx, struct failed_htlc, 0); *failed_sides = tal_arr(ctx, enum side, 0); for (hin = htlc_in_map_first(&peer->ld->htlcs_in, &ini); hin; hin = htlc_in_map_next(&peer->ld->htlcs_in, &ini)) { if (hin->key.peer != peer) continue; add_htlc(htlcs, htlc_states, hin->key.id, hin->msatoshi, &hin->payment_hash, hin->cltv_expiry, hin->onion_routing_packet, hin->hstate); if (hin->failuremsg) add_fail(hin->key.id, REMOTE, hin->failuremsg, failed_htlcs, failed_sides); if (hin->preimage) add_fulfill(hin->key.id, REMOTE, hin->preimage, fulfilled_htlcs, fulfilled_sides); } for (hout = htlc_out_map_first(&peer->ld->htlcs_out, &outi); hout; hout = htlc_out_map_next(&peer->ld->htlcs_out, &outi)) { if (hout->key.peer != peer) continue; add_htlc(htlcs, htlc_states, hout->key.id, hout->msatoshi, &hout->payment_hash, hout->cltv_expiry, hout->onion_routing_packet, hout->hstate); if (hout->failuremsg) add_fail(hout->key.id, LOCAL, hout->failuremsg, failed_htlcs, failed_sides); if (hout->preimage) add_fulfill(hout->key.id, LOCAL, hout->preimage, fulfilled_htlcs, fulfilled_sides); } } /* BOLT #2: * * For HTLCs we offer: the timeout deadline when we have to fail the channel * and time it out on-chain. This is `G` blocks after the HTLC * `cltv_expiry`; 1 block is reasonable. */ static u32 htlc_out_deadline(const struct htlc_out *hout) { return hout->cltv_expiry + 1; } /* BOLT #2: * * For HTLCs we accept and have a preimage: the fulfillment deadline when we * have to fail the channel and fulfill the HTLC onchain before its * `cltv_expiry`. This is steps 4-7 above, which means a deadline of `2R+G+S` * blocks before `cltv_expiry`; 7 blocks is reasonable. */ /* We approximate this, by using half the cltv_expiry_delta (3R+2G+2S), * rounded up. */ static u32 htlc_in_deadline(const struct lightningd *ld, const struct htlc_in *hin) { return hin->cltv_expiry - (ld->config.cltv_expiry_delta + 1)/2; } void notify_new_block(struct lightningd *ld, u32 height) { bool removed; /* BOLT #2: * * A node ... MUST fail the channel if an HTLC which it offered is in * either node's current commitment transaction past this timeout * deadline. */ /* FIXME: use db to look this up in one go (earliest deadline per-peer) */ do { struct htlc_out *hout; struct htlc_out_map_iter outi; removed = false; for (hout = htlc_out_map_first(&ld->htlcs_out, &outi); hout; hout = htlc_out_map_next(&ld->htlcs_out, &outi)) { /* Not timed out yet? */ if (height < htlc_out_deadline(hout)) continue; /* Peer on chain already? */ if (peer_on_chain(hout->key.peer)) continue; /* Peer already failed, or we hit it? */ if (hout->key.peer->error) continue; peer_fail_permanent(hout->key.peer, "Offered HTLC %"PRIu64 " %s cltv %u hit deadline", hout->key.id, htlc_state_name(hout->hstate), hout->cltv_expiry); removed = true; } /* Iteration while removing is safe, but can skip entries! */ } while (removed); /* BOLT #2: * * A node MUST estimate a fulfillment deadline for each HTLC it is * attempting to fulfill. A node ... MUST fail the connection if a * HTLC it has fulfilled is in either node's current commitment * transaction past this fulfillment deadline. */ do { struct htlc_in *hin; struct htlc_in_map_iter ini; removed = false; for (hin = htlc_in_map_first(&ld->htlcs_in, &ini); hin; hin = htlc_in_map_next(&ld->htlcs_in, &ini)) { /* Not fulfilled? If overdue, that's their problem... */ if (!hin->preimage) continue; /* Not timed out yet? */ if (height < htlc_in_deadline(ld, hin)) continue; /* Peer on chain already? */ if (peer_on_chain(hin->key.peer)) continue; /* Peer already failed, or we hit it? */ if (hin->key.peer->error) continue; peer_fail_permanent(hin->key.peer, "Fulfilled HTLC %"PRIu64 " %s cltv %u hit deadline", hin->key.id, htlc_state_name(hin->hstate), hin->cltv_expiry); removed = true; } /* Iteration while removing is safe, but can skip entries! */ } while (removed); } void notify_feerate_change(struct lightningd *ld) { struct peer *peer; /* FIXME: We should notify onchaind about NORMAL fee change in case * it's going to generate more txs. */ list_for_each(&ld->peers, peer, list) { u8 *msg; if (!peer_fees_can_change(peer)) continue; /* FIXME: We choose not to drop to chain if we can't contact * peer. We *could* do so, however. */ if (!peer->owner) continue; msg = towire_channel_feerates(peer, get_feerate(ld->topology, FEERATE_IMMEDIATE), feerate_min(ld), feerate_max(ld)); subd_send_msg(peer->owner, take(msg)); } }