#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 "gen_onchain_types_names.h" /* stdin == requests */ #define REQ_FD STDIN_FILENO #define HSM_FD 3 /* Required in various places: keys for commitment transaction. */ static const struct keyset *keyset; /* IFF it's their commitment tx: HSM can't derive their per-commitment point! */ static const struct pubkey *remote_per_commitment_point; /* The commitment number we're dealing with (if not mutual close) */ static u64 commit_num; /* The feerate to use when we generate transactions. */ static u32 feerate_per_kw; /* Min and max feerates we ever used */ static u32 min_possible_feerate, max_possible_feerate; /* The dust limit to use when we generate transactions. */ static struct amount_sat dust_limit; /* The CSV delays for each side. */ static u32 to_self_delay[NUM_SIDES]; /* Where we send money to (our wallet) */ static struct pubkey our_wallet_pubkey; /* Their revocation secret (only if they cheated). */ static const struct secret *remote_per_commitment_secret; /* one value is useful for a few witness scripts */ static const u8 ONE = 0x1; /* When to tell master about HTLCs which are missing/timed out */ static u32 reasonable_depth; /* The messages to send at that depth. */ static u8 **missing_htlc_msgs; /* If we broadcast a tx, or need a delay to resolve the output. */ struct proposed_resolution { /* This can be NULL if our proposal is to simply ignore it after depth */ const struct bitcoin_tx *tx; /* Non-zero if this is CSV-delayed. */ u32 depth_required; enum tx_type tx_type; }; /* How it actually got resolved. */ struct resolution { struct bitcoin_txid txid; unsigned int depth; enum tx_type tx_type; }; struct tracked_output { enum tx_type tx_type; struct bitcoin_txid txid; u32 tx_blockheight; /* FIXME: Convert all depths to blocknums, then just get new blk msgs */ u32 depth; u32 outnum; struct amount_sat sat; enum output_type output_type; /* If it is an HTLC, this is set, wscript is non-NULL. */ struct htlc_stub htlc; const u8 *wscript; /* If it's an HTLC off our unilateral, this is their sig for htlc_tx */ const struct bitcoin_signature *remote_htlc_sig; /* Our proposed solution (if any) */ struct proposed_resolution *proposal; /* If it is resolved. */ struct resolution *resolved; }; /* We vary feerate until signature they offered matches. */ static bool grind_htlc_tx_fee(struct amount_sat *fee, struct bitcoin_tx *tx, const struct bitcoin_signature *remotesig, const u8 *wscript, u64 weight) { struct amount_sat prev_fee = AMOUNT_SAT(UINT64_MAX); for (u64 i = min_possible_feerate; i <= max_possible_feerate; i++) { /* BOLT #3: * * The fee for an HTLC-timeout transaction: * - MUST BE calculated to match: * 1. Multiply `feerate_per_kw` by 663 and divide by 1000 * (rounding down). * * The fee for an HTLC-success transaction: * - MUST BE calculated to match: * 1. Multiply `feerate_per_kw` by 703 and divide by 1000 * (rounding down). */ struct amount_sat out; *fee = amount_tx_fee(i, weight); /* Minor optimization: don't check same fee twice */ if (amount_sat_eq(*fee, prev_fee)) continue; prev_fee = *fee; if (!amount_sat_sub(&out, *tx->input_amounts[0], *fee)) break; bitcoin_tx_output_set_amount(tx, 0, &out); if (!check_tx_sig(tx, 0, NULL, wscript, &keyset->other_htlc_key, remotesig)) continue; status_trace("grind feerate_per_kw for %"PRIu64" = %"PRIu64, weight, i); return true; } return false; } static bool set_htlc_timeout_fee(struct bitcoin_tx *tx, const struct bitcoin_signature *remotesig, const u8 *wscript) { static struct amount_sat fee = AMOUNT_SAT_INIT(UINT64_MAX); struct amount_sat amount = bitcoin_tx_output_get_amount(tx, 0); /* BOLT #3: * * The fee for an HTLC-timeout transaction: * - MUST BE calculated to match: * 1. Multiply `feerate_per_kw` by 663 and divide by 1000 (rounding * down). */ if (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) return grind_htlc_tx_fee(&fee, tx, remotesig, wscript, 663); if (!amount_sat_sub(&amount, amount, fee)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Cannot deduct htlc-timeout fee %s from tx %s", type_to_string(tmpctx, struct amount_sat, &fee), type_to_string(tmpctx, struct bitcoin_tx, tx)); bitcoin_tx_output_set_amount(tx, 0, &amount); return check_tx_sig(tx, 0, NULL, wscript, &keyset->other_htlc_key, remotesig); } static void set_htlc_success_fee(struct bitcoin_tx *tx, const struct bitcoin_signature *remotesig, const u8 *wscript) { static struct amount_sat amt, fee = AMOUNT_SAT_INIT(UINT64_MAX); /* BOLT #3: * * The fee for an HTLC-success transaction: * - MUST BE calculated to match: * 1. Multiply `feerate_per_kw` by 703 and divide by 1000 * (rounding down). */ if (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) { if (!grind_htlc_tx_fee(&fee, tx, remotesig, wscript, 703)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "htlc_success_fee can't be found " " for tx %s, signature %s, wscript %s", type_to_string(tmpctx, struct bitcoin_tx, tx), type_to_string(tmpctx, struct bitcoin_signature, remotesig), tal_hex(tmpctx, wscript)); return; } amt = bitcoin_tx_output_get_amount(tx, 0); if (!amount_sat_sub(&amt, amt, fee)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Cannot deduct htlc-success fee %s from tx %s", type_to_string(tmpctx, struct amount_sat, &fee), type_to_string(tmpctx, struct bitcoin_tx, tx)); bitcoin_tx_output_set_amount(tx, 0, &amt); if (check_tx_sig(tx, 0, NULL, wscript, &keyset->other_htlc_key, remotesig)) return; status_failed(STATUS_FAIL_INTERNAL_ERROR, "htlc_success_fee %s failed sigcheck " " for tx %s, signature %s, wscript %s", type_to_string(tmpctx, struct amount_sat, &fee), type_to_string(tmpctx, struct bitcoin_tx, tx), type_to_string(tmpctx, struct bitcoin_signature, remotesig), tal_hex(tmpctx, wscript)); } static const char *tx_type_name(enum tx_type tx_type) { size_t i; for (i = 0; enum_tx_type_names[i].name; i++) if (enum_tx_type_names[i].v == tx_type) return enum_tx_type_names[i].name; return "unknown"; } static const char *output_type_name(enum output_type output_type) { size_t i; for (i = 0; enum_output_type_names[i].name; i++) if (enum_output_type_names[i].v == output_type) return enum_output_type_names[i].name; return "unknown"; } static u8 *delayed_payment_to_us(const tal_t *ctx, struct bitcoin_tx *tx, const u8 *wscript) { return towire_hsm_sign_delayed_payment_to_us(ctx, commit_num, tx, wscript, *tx->input_amounts[0]); } static u8 *remote_htlc_to_us(const tal_t *ctx, struct bitcoin_tx *tx, const u8 *wscript) { return towire_hsm_sign_remote_htlc_to_us(ctx, remote_per_commitment_point, tx, wscript, *tx->input_amounts[0]); } static u8 *penalty_to_us(const tal_t *ctx, struct bitcoin_tx *tx, const u8 *wscript) { return towire_hsm_sign_penalty_to_us(ctx, remote_per_commitment_secret, tx, wscript, *tx->input_amounts[0]); } /* * This covers: * 1. to-us output spend (` 0`) * 2. the their-commitment, our HTLC timeout case (` 0`), * 3. the their-commitment, our HTLC redeem case (` `) * 4. the their-revoked-commitment, to-local (` 1`) * 5. the their-revoked-commitment, htlc (` `) * * Overrides *tx_type if it all turns to dust. */ static struct bitcoin_tx *tx_to_us(const tal_t *ctx, u8 *(*hsm_sign_msg)(const tal_t *ctx, struct bitcoin_tx *tx, const u8 *wscript), struct tracked_output *out, u32 to_self_delay, u32 locktime, const void *elem, size_t elemsize, const u8 *wscript, enum tx_type *tx_type) { struct bitcoin_tx *tx; struct amount_sat fee, min_out, amt; struct bitcoin_signature sig; size_t weight; u8 *msg; u8 **witness; tx = bitcoin_tx(ctx, 1, 1); tx->wtx->locktime = locktime; bitcoin_tx_add_input(tx, &out->txid, out->outnum, to_self_delay, &out->sat, NULL); bitcoin_tx_add_output( tx, scriptpubkey_p2wpkh(tx, &our_wallet_pubkey), &out->sat); /* Worst-case sig is 73 bytes */ weight = measure_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(wscript); fee = amount_tx_fee(feerate_per_kw, weight); /* Result is trivial? Spend with small feerate, but don't wait * around for it as it might not confirm. */ if (!amount_sat_add(&min_out, dust_limit, fee)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Cannot add dust_limit %s and fee %s", type_to_string(tmpctx, struct amount_sat, &dust_limit), type_to_string(tmpctx, struct amount_sat, &fee)); if (amount_sat_less(out->sat, min_out)) { /* FIXME: We should use SIGHASH_NONE so others can take it */ fee = amount_tx_fee(feerate_floor(), weight); status_unusual("TX %s amount %s too small to" " pay reasonable fee, using minimal fee" " and ignoring", tx_type_name(*tx_type), type_to_string(tmpctx, struct amount_sat, &out->sat)); *tx_type = IGNORING_TINY_PAYMENT; } /* This can only happen if feerate_floor() is still too high; shouldn't * happen! */ if (!amount_sat_sub(&amt, out->sat, fee)) { amt = dust_limit; status_broken("TX %s can't afford minimal feerate" "; setting output to %s", tx_type_name(*tx_type), type_to_string(tmpctx, struct amount_sat, &amt)); } bitcoin_tx_output_set_amount(tx, 0, &amt); if (!wire_sync_write(HSM_FD, take(hsm_sign_msg(NULL, tx, wscript)))) status_failed(STATUS_FAIL_HSM_IO, "Writing sign request to hsm"); msg = wire_sync_read(tmpctx, HSM_FD); if (!msg || !fromwire_hsm_sign_tx_reply(msg, &sig)) { status_failed(STATUS_FAIL_HSM_IO, "Reading sign_tx_reply: %s", tal_hex(tmpctx, msg)); } witness = bitcoin_witness_sig_and_element(tx, &sig, elem, elemsize, wscript); bitcoin_tx_input_set_witness(tx, 0, witness); return tx; } static void hsm_sign_local_htlc_tx(struct bitcoin_tx *tx, const u8 *wscript, struct bitcoin_signature *sig) { u8 *msg = towire_hsm_sign_local_htlc_tx(NULL, commit_num, tx, wscript, *tx->input_amounts[0]); if (!wire_sync_write(HSM_FD, take(msg))) status_failed(STATUS_FAIL_HSM_IO, "Writing sign_local_htlc_tx to hsm"); msg = wire_sync_read(tmpctx, HSM_FD); if (!msg || !fromwire_hsm_sign_tx_reply(msg, sig)) status_failed(STATUS_FAIL_HSM_IO, "Reading sign_local_htlc_tx: %s", tal_hex(tmpctx, msg)); } static void hsm_get_per_commitment_point(struct pubkey *per_commitment_point) { u8 *msg = towire_hsm_get_per_commitment_point(NULL, commit_num); struct secret *unused; if (!wire_sync_write(HSM_FD, take(msg))) status_failed(STATUS_FAIL_HSM_IO, "Writing sign_htlc_tx to hsm"); msg = wire_sync_read(tmpctx, HSM_FD); if (!msg || !fromwire_hsm_get_per_commitment_point_reply(tmpctx, msg, per_commitment_point, &unused)) status_failed(STATUS_FAIL_HSM_IO, "Reading hsm_get_per_commitment_point_reply: %s", tal_hex(tmpctx, msg)); } static struct tracked_output * new_tracked_output(struct tracked_output ***outs, const struct bitcoin_txid *txid, u32 tx_blockheight, enum tx_type tx_type, u32 outnum, struct amount_sat sat, enum output_type output_type, const struct htlc_stub *htlc, const u8 *wscript, const secp256k1_ecdsa_signature *remote_htlc_sig) { struct tracked_output *out = tal(*outs, struct tracked_output); status_trace("Tracking output %u of %s: %s/%s", outnum, type_to_string(tmpctx, struct bitcoin_txid, txid), tx_type_name(tx_type), output_type_name(output_type)); out->tx_type = tx_type; out->txid = *txid; out->tx_blockheight = tx_blockheight; out->depth = 0; out->outnum = outnum; out->sat = sat; out->output_type = output_type; out->proposal = NULL; out->resolved = NULL; if (htlc) out->htlc = *htlc; out->wscript = tal_steal(out, wscript); if (remote_htlc_sig) { struct bitcoin_signature *sig; sig = tal(out, struct bitcoin_signature); sig->s = *remote_htlc_sig; sig->sighash_type = SIGHASH_ALL; out->remote_htlc_sig = sig; } else out->remote_htlc_sig = NULL; tal_arr_expand(outs, out); return out; } static void ignore_output(struct tracked_output *out) { status_trace("Ignoring output %u of %s: %s/%s", out->outnum, type_to_string(tmpctx, struct bitcoin_txid, &out->txid), tx_type_name(out->tx_type), output_type_name(out->output_type)); out->resolved = tal(out, struct resolution); out->resolved->txid = out->txid; out->resolved->depth = 0; out->resolved->tx_type = SELF; } static enum wallet_tx_type onchain_txtype_to_wallet_txtype(enum tx_type t) { switch (t) { case FUNDING_TRANSACTION: return TX_CHANNEL_FUNDING; case MUTUAL_CLOSE: return TX_CHANNEL_CLOSE; case OUR_UNILATERAL: return TX_CHANNEL_UNILATERAL; case THEIR_HTLC_FULFILL_TO_US: case OUR_HTLC_SUCCESS_TX: return TX_CHANNEL_HTLC_SUCCESS; case OUR_HTLC_TIMEOUT_TO_US: case OUR_HTLC_TIMEOUT_TX: return TX_CHANNEL_HTLC_TIMEOUT; case OUR_DELAYED_RETURN_TO_WALLET: case SELF: return TX_CHANNEL_SWEEP; case OUR_PENALTY_TX: return TX_CHANNEL_PENALTY; case THEIR_UNILATERAL: case UNKNOWN_UNILATERAL: case THEIR_REVOKED_UNILATERAL: return TX_CHANNEL_UNILATERAL | TX_THEIRS; case THEIR_HTLC_TIMEOUT_TO_THEM: return TX_CHANNEL_HTLC_TIMEOUT | TX_THEIRS; case OUR_HTLC_FULFILL_TO_THEM: return TX_CHANNEL_HTLC_SUCCESS | TX_THEIRS; case IGNORING_TINY_PAYMENT: case UNKNOWN_TXTYPE: return TX_UNKNOWN; } abort(); } static void proposal_meets_depth(struct tracked_output *out) { /* If we simply wanted to ignore it after some depth */ if (!out->proposal->tx) { ignore_output(out); return; } status_trace("Broadcasting %s (%s) to resolve %s/%s", tx_type_name(out->proposal->tx_type), type_to_string(tmpctx, struct bitcoin_tx, out->proposal->tx), tx_type_name(out->tx_type), output_type_name(out->output_type)); wire_sync_write( REQ_FD, take(towire_onchain_broadcast_tx( NULL, out->proposal->tx, onchain_txtype_to_wallet_txtype(out->proposal->tx_type)))); /* Don't wait for this if we're ignoring the tiny payment. */ if (out->proposal->tx_type == IGNORING_TINY_PAYMENT) { ignore_output(out); out->proposal = tal_free(out->proposal); } /* We will get a callback when it's in a block. */ } static void propose_resolution(struct tracked_output *out, const struct bitcoin_tx *tx, unsigned int depth_required, enum tx_type tx_type) { status_trace("Propose handling %s/%s by %s (%s) after %u blocks", tx_type_name(out->tx_type), output_type_name(out->output_type), tx_type_name(tx_type), tx ? type_to_string(tmpctx, struct bitcoin_tx, tx):"IGNORING", depth_required); out->proposal = tal(out, struct proposed_resolution); out->proposal->tx = tal_steal(out->proposal, tx); out->proposal->depth_required = depth_required; out->proposal->tx_type = tx_type; if (depth_required == 0) proposal_meets_depth(out); } static void propose_resolution_at_block(struct tracked_output *out, const struct bitcoin_tx *tx, unsigned int block_required, enum tx_type tx_type) { u32 depth; /* Expiry could be in the past! */ if (block_required < out->tx_blockheight) depth = 0; else /* Note that out->tx_blockheight is already at depth 1 */ depth = block_required - out->tx_blockheight + 1; propose_resolution(out, tx, depth, tx_type); } static bool is_valid_sig(const u8 *e) { struct bitcoin_signature sig; return signature_from_der(e, tal_count(e), &sig); } /* We ignore things which look like signatures. */ static bool input_similar(const struct wally_tx_input *i1, const struct wally_tx_input *i2) { u8 *s1, *s2; if (!memeq(i1->txhash, WALLY_TXHASH_LEN, i2->txhash, WALLY_TXHASH_LEN)) return false; if (i1->index != i2->index) return false; if (!scripteq(i1->script, i2->script)) return false; if (i1->sequence != i2->sequence) return false; if (i1->witness->num_items != i2->witness->num_items) return false; for (size_t i = 0; i < i1->witness->num_items; i++) { /* Need to wrap these in `tal_arr`s since the primitives * except to be able to call tal_bytelen on them */ s1 = tal_dup_arr(tmpctx, u8, i1->witness->items[i].witness, i1->witness->items[i].witness_len, 0); s2 = tal_dup_arr(tmpctx, u8, i2->witness->items[i].witness, i2->witness->items[i].witness_len, 0); if (scripteq(s1, s2)) continue; if (is_valid_sig(s1) && is_valid_sig(s2)) continue; return false; } return true; } /* This simple case: true if this was resolved by our proposal. */ static bool resolved_by_proposal(struct tracked_output *out, const struct bitcoin_tx *tx) { /* If there's no TX associated, it's not us. */ if (!out->proposal->tx) return false; /* Our proposal can change as feerates change. Input * comparison (ignoring signatures) works pretty well. * * FIXME: Better would be to compare outputs, but they weren't * saved to db correctly until now. (COMPAT_V052) */ if (tx->wtx->num_inputs != out->proposal->tx->wtx->num_inputs) return false; for (size_t i = 0; i < tx->wtx->num_inputs; i++) { if (!input_similar(&tx->wtx->inputs[i], &out->proposal->tx->wtx->inputs[i])) return false; } out->resolved = tal(out, struct resolution); bitcoin_txid(tx, &out->resolved->txid); status_trace("Resolved %s/%s by our proposal %s (%s)", tx_type_name(out->tx_type), output_type_name(out->output_type), tx_type_name(out->proposal->tx_type), type_to_string(tmpctx, struct bitcoin_txid, &out->resolved->txid)); out->resolved->depth = 0; out->resolved->tx_type = out->proposal->tx_type; /* Don't need proposal any more */ out->proposal = tal_free(out->proposal); return true; } /* Otherwise, we figure out what happened and then call this. */ static void resolved_by_other(struct tracked_output *out, const struct bitcoin_txid *txid, enum tx_type tx_type) { out->resolved = tal(out, struct resolution); out->resolved->txid = *txid; out->resolved->depth = 0; out->resolved->tx_type = tx_type; status_trace("Resolved %s/%s by %s (%s)", tx_type_name(out->tx_type), output_type_name(out->output_type), tx_type_name(tx_type), type_to_string(tmpctx, struct bitcoin_txid, txid)); } static void unknown_spend(struct tracked_output *out, const struct bitcoin_tx *tx) { out->resolved = tal(out, struct resolution); bitcoin_txid(tx, &out->resolved->txid); out->resolved->depth = 0; out->resolved->tx_type = UNKNOWN_TXTYPE; /* FIXME: we need a louder warning! */ status_trace("Unknown spend of %s/%s by %s", tx_type_name(out->tx_type), output_type_name(out->output_type), type_to_string(tmpctx, struct bitcoin_tx, tx)); } static u64 unmask_commit_number(const struct bitcoin_tx *tx, enum side funder, const struct pubkey *local_payment_basepoint, const struct pubkey *remote_payment_basepoint) { u64 obscurer; const struct pubkey *keys[NUM_SIDES]; keys[LOCAL] = local_payment_basepoint; keys[REMOTE] = remote_payment_basepoint; /* BOLT #3: * * The 48-bit commitment number is obscured by `XOR` with the lower 48 bits of... */ obscurer = commit_number_obscurer(keys[funder], keys[!funder]); /* BOLT #3: * * * locktime: upper 8 bits are 0x20, lower 24 bits are the lower 24 bits of the obscured commitment number *... * * `txin[0]` sequence: upper 8 bits are 0x80, lower 24 bits are upper 24 bits of the obscured commitment number */ return ((tx->wtx->locktime & 0x00FFFFFF) | (tx->wtx->inputs[0].sequence & (u64)0x00FFFFFF) << 24) ^ obscurer; } static bool is_mutual_close(const struct bitcoin_tx *tx, const u8 *local_scriptpubkey, const u8 *remote_scriptpubkey) { size_t i; bool local_matched = false, remote_matched = false; for (i = 0; i < tx->wtx->num_outputs; i++) { const u8 *script = bitcoin_tx_output_get_script(tmpctx, tx, i); /* To be paranoid, we only let each one match once. */ if (scripteq(script, local_scriptpubkey) && !local_matched) local_matched = true; else if (scripteq(script, remote_scriptpubkey) && !remote_matched) remote_matched = true; else return false; } return true; } /* We only ever send out one, so matching it is easy. */ static bool is_local_commitment(const struct bitcoin_txid *txid, const struct bitcoin_txid *our_broadcast_txid) { return bitcoin_txid_eq(txid, our_broadcast_txid); } /* BOLT #5: * * Outputs that are *resolved* are considered *irrevocably resolved* * once the remote's *resolving* transaction is included in a block at least 100 * deep, on the most-work blockchain. */ static size_t num_not_irrevocably_resolved(struct tracked_output **outs) { size_t i, num = 0; for (i = 0; i < tal_count(outs); i++) { if (!outs[i]->resolved || outs[i]->resolved->depth < 100) num++; } return num; } static u32 prop_blockheight(const struct tracked_output *out) { return out->tx_blockheight + out->proposal->depth_required; } static void billboard_update(struct tracked_output **outs) { const struct tracked_output *best = NULL; /* Highest priority is to report on proposals we have */ for (size_t i = 0; i < tal_count(outs); i++) { if (!outs[i]->proposal) continue; if (!best || prop_blockheight(outs[i]) < prop_blockheight(best)) best = outs[i]; } if (best) { /* If we've broadcast and not seen yet, this happens */ if (best->proposal->depth_required <= best->depth) { peer_billboard(false, "%u outputs unresolved: waiting confirmation that we spent %s (%s:%u) using %s", num_not_irrevocably_resolved(outs), output_type_name(best->output_type), type_to_string(tmpctx, struct bitcoin_txid, &best->txid), best->outnum, tx_type_name(best->proposal->tx_type)); } else { peer_billboard(false, "%u outputs unresolved: in %u blocks will spend %s (%s:%u) using %s", num_not_irrevocably_resolved(outs), best->proposal->depth_required - best->depth, output_type_name(best->output_type), type_to_string(tmpctx, struct bitcoin_txid, &best->txid), best->outnum, tx_type_name(best->proposal->tx_type)); } return; } /* Now, just report on the last thing we're waiting out. */ for (size_t i = 0; i < tal_count(outs); i++) { /* FIXME: Can this happen? No proposal, no resolution? */ if (!outs[i]->resolved) continue; if (!best || outs[i]->resolved->depth < best->resolved->depth) best = outs[i]; } if (best) { peer_billboard(false, "All outputs resolved:" " waiting %u more blocks before forgetting" " channel", best->resolved->depth < 100 ? 100 - best->resolved->depth : 0); return; } /* Not sure this can happen, but take last one (there must be one!) */ best = outs[tal_count(outs)-1]; peer_billboard(false, "%u outputs unresolved: %s is one (depth %u)", num_not_irrevocably_resolved(outs), output_type_name(best->output_type), best->depth); } static void unwatch_tx(const struct bitcoin_tx *tx) { u8 *msg; struct bitcoin_txid txid; bitcoin_txid(tx, &txid); msg = towire_onchain_unwatch_tx(tx, &txid); wire_sync_write(REQ_FD, take(msg)); } static void handle_htlc_onchain_fulfill(struct tracked_output *out, const struct bitcoin_tx *tx) { const u8 *witness_preimage; struct preimage preimage; struct sha256 sha; struct ripemd160 ripemd; /* Our HTLC, they filled (must be an HTLC-success tx). */ if (out->tx_type == THEIR_UNILATERAL) { /* BOLT #3: * * ## HTLC-Timeout and HTLC-Success Transactions * * ... `txin[0]` witness stack: `0 * ` for HTLC-success */ if (tx->wtx->inputs[0].witness->num_items != 5) /* +1 for wscript */ status_failed(STATUS_FAIL_INTERNAL_ERROR, "%s/%s spent with weird witness %zu", tx_type_name(out->tx_type), output_type_name(out->output_type), tx->wtx->inputs[0].witness->num_items); witness_preimage = bitcoin_tx_input_get_witness(tmpctx, tx, 0, 3); } else if (out->tx_type == OUR_UNILATERAL) { /* BOLT #3: * * The remote node can redeem the HTLC with the witness: * * */ if (tx->wtx->inputs[0].witness->num_items != 3) /* +1 for wscript */ status_failed(STATUS_FAIL_INTERNAL_ERROR, "%s/%s spent with weird witness %zu", tx_type_name(out->tx_type), output_type_name(out->output_type), tx->wtx->inputs[0].witness->num_items); witness_preimage = bitcoin_tx_input_get_witness(tmpctx, tx, 0, 1); } else status_failed(STATUS_FAIL_INTERNAL_ERROR, "onchain_fulfill for %s/%s?", tx_type_name(out->tx_type), output_type_name(out->output_type)); if (tal_count(witness_preimage) != sizeof(preimage)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "%s/%s spent with bad witness length %zu", tx_type_name(out->tx_type), output_type_name(out->output_type), tal_count(witness_preimage)); memcpy(&preimage, witness_preimage, sizeof(preimage)); sha256(&sha, &preimage, sizeof(preimage)); ripemd160(&ripemd, &sha, sizeof(sha)); if (!ripemd160_eq(&ripemd, &out->htlc.ripemd)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "%s/%s spent with bad preimage %s (ripemd not %s)", tx_type_name(out->tx_type), output_type_name(out->output_type), type_to_string(tmpctx, struct preimage, &preimage), type_to_string(tmpctx, struct ripemd160, &out->htlc.ripemd)); /* Tell master we found a preimage. */ status_trace("%s/%s gave us preimage %s", tx_type_name(out->tx_type), output_type_name(out->output_type), type_to_string(tmpctx, struct preimage, &preimage)); wire_sync_write(REQ_FD, take(towire_onchain_extracted_preimage(NULL, &preimage))); } static void resolve_htlc_tx(struct tracked_output ***outs, size_t out_index, const struct bitcoin_tx *htlc_tx, const struct bitcoin_txid *htlc_txid, u32 tx_blockheight) { struct tracked_output *out; struct bitcoin_tx *tx; struct amount_sat amt; enum tx_type tx_type = OUR_DELAYED_RETURN_TO_WALLET; u8 *wscript = bitcoin_wscript_htlc_tx(htlc_tx, to_self_delay[LOCAL], &keyset->self_revocation_key, &keyset->self_delayed_payment_key); /* BOLT #5: * * - SHOULD resolve the HTLC-timeout transaction by spending it to * a convenient address... * - MUST wait until the `OP_CHECKSEQUENCEVERIFY` delay has passed * (as specified by the remote node's `open_channel` * `to_self_delay` field) before spending that HTLC-timeout * output. */ amt = bitcoin_tx_output_get_amount(htlc_tx, 0); out = new_tracked_output(outs, htlc_txid, tx_blockheight, (*outs)[out_index]->resolved->tx_type, 0, amt, DELAYED_OUTPUT_TO_US, NULL, NULL, NULL); /* BOLT #3: * * ## HTLC-Timeout and HTLC-Success Transactions * * These HTLC transactions are almost identical, except the * HTLC-timeout transaction is timelocked. * * ... to collect the output, the local node uses an input with * nSequence `to_self_delay` and a witness stack ` * 0` */ tx = tx_to_us(*outs, delayed_payment_to_us, out, to_self_delay[LOCAL], 0, NULL, 0, wscript, &tx_type); propose_resolution(out, tx, to_self_delay[LOCAL], tx_type); } /* BOLT #5: * * - MUST *resolve* the _remote node's HTLC-timeout transaction_ by spending it * using the revocation private key. * - MUST *resolve* the _remote node's HTLC-success transaction_ by spending it * using the revocation private key. */ static void steal_htlc_tx(struct tracked_output *out) { struct bitcoin_tx *tx; enum tx_type tx_type = OUR_PENALTY_TX; /* BOLT #3: * * To spend this via penalty, the remote node uses a witness stack * ` 1` */ tx = tx_to_us(out, penalty_to_us, out, 0xFFFFFFFF, 0, &ONE, sizeof(ONE), out->wscript, &tx_type); propose_resolution(out, tx, 0, tx_type); } static void onchain_transaction_annotate(const struct bitcoin_txid *txid, enum wallet_tx_type type) { u8 *msg = towire_onchain_transaction_annotate(tmpctx, txid, type); wire_sync_write(REQ_FD, take(msg)); } /* An output has been spent: see if it resolves something we care about. */ static void output_spent(struct tracked_output ***outs, const struct bitcoin_tx *tx, u32 input_num, u32 tx_blockheight) { struct bitcoin_txid txid, tmptxid, spendertxid; bitcoin_txid(tx, &txid); bitcoin_txid(tx, &spendertxid); for (size_t i = 0; i < tal_count(*outs); i++) { struct tracked_output *out = (*outs)[i]; if (out->resolved) continue; if (tx->wtx->inputs[input_num].index != out->outnum) continue; bitcoin_tx_input_get_txid(tx, input_num, &tmptxid); if (!bitcoin_txid_eq(&tmptxid, &out->txid)) continue; /* Was this our resolution? */ if (resolved_by_proposal(out, tx)) { /* If it's our htlc tx, we need to resolve that, too. */ if (out->resolved->tx_type == OUR_HTLC_SUCCESS_TX || out->resolved->tx_type == OUR_HTLC_TIMEOUT_TX) resolve_htlc_tx(outs, i, tx, &txid, tx_blockheight); return; } switch (out->output_type) { case OUTPUT_TO_US: case DELAYED_OUTPUT_TO_US: unknown_spend(out, tx); break; case THEIR_HTLC: if (out->tx_type == THEIR_REVOKED_UNILATERAL) { steal_htlc_tx(out); } else { /* We ignore this timeout tx, since we should * resolve by ignoring once we reach depth. */ onchain_transaction_annotate( &spendertxid, TX_CHANNEL_HTLC_TIMEOUT | TX_THEIRS); } break; case OUR_HTLC: /* The only way they can spend this: fulfill; even * if it's revoked: */ /* BOLT #5: * * ## HTLC Output Handling: Local Commitment, Local Offers *... * - MUST extract the payment preimage from the * transaction input witness. *... * ## HTLC Output Handling: Remote Commitment, Local Offers *... * - MUST extract the payment preimage from the * HTLC-success transaction input witness. */ handle_htlc_onchain_fulfill(out, tx); if (out->tx_type == THEIR_REVOKED_UNILATERAL) steal_htlc_tx(out); else { /* BOLT #5: * * ## HTLC Output Handling: Local Commitment, * Local Offers *... * - if the commitment transaction HTLC output * is spent using the payment preimage, the * output is considered *irrevocably resolved* */ ignore_output(out); onchain_transaction_annotate( &spendertxid, TX_CHANNEL_HTLC_SUCCESS | TX_THEIRS); } break; case FUNDING_OUTPUT: /* Master should be restarting us, as this implies * that our old tx was unspent. */ status_failed(STATUS_FAIL_INTERNAL_ERROR, "Funding output spent again!"); /* Um, we don't track these! */ case OUTPUT_TO_THEM: case DELAYED_OUTPUT_TO_THEM: status_failed(STATUS_FAIL_INTERNAL_ERROR, "Tracked spend of %s/%s?", tx_type_name(out->tx_type), output_type_name(out->output_type)); } return; } bitcoin_tx_input_get_txid(tx, input_num, &txid); /* Not interesting to us, so unwatch the tx and all its outputs */ status_trace("Notified about tx %s output %u spend, but we don't care", type_to_string(tmpctx, struct bitcoin_txid, &txid), tx->wtx->inputs[input_num].index); unwatch_tx(tx); } static void update_resolution_depth(struct tracked_output *out, u32 depth) { bool reached_reasonable_depth; status_trace("%s/%s->%s depth %u", tx_type_name(out->tx_type), output_type_name(out->output_type), tx_type_name(out->resolved->tx_type), depth); /* We only set this once. */ reached_reasonable_depth = (out->resolved->depth < reasonable_depth && depth >= reasonable_depth); /* BOLT #5: * * - if the commitment transaction HTLC output has *timed out* and * hasn't been *resolved*: * - MUST *resolve* the output by spending it using the HTLC-timeout * transaction. * - once the resolving transaction has reached reasonable depth: * - MUST fail the corresponding incoming HTLC (if any). */ if ((out->resolved->tx_type == OUR_HTLC_TIMEOUT_TX || out->resolved->tx_type == OUR_HTLC_TIMEOUT_TO_US) && reached_reasonable_depth) { u8 *msg; status_trace("%s/%s reached reasonable depth %u", tx_type_name(out->tx_type), output_type_name(out->output_type), depth); msg = towire_onchain_htlc_timeout(out, &out->htlc); wire_sync_write(REQ_FD, take(msg)); } out->resolved->depth = depth; } static void tx_new_depth(struct tracked_output **outs, const struct bitcoin_txid *txid, u32 depth) { size_t i; /* Special handling for commitment tx reaching depth */ if (bitcoin_txid_eq(&outs[0]->resolved->txid, txid) && depth >= reasonable_depth && missing_htlc_msgs) { status_trace("Sending %zu missing htlc messages", tal_count(missing_htlc_msgs)); for (i = 0; i < tal_count(missing_htlc_msgs); i++) wire_sync_write(REQ_FD, missing_htlc_msgs[i]); /* Don't do it again. */ missing_htlc_msgs = tal_free(missing_htlc_msgs); } for (i = 0; i < tal_count(outs); i++) { /* Update output depth. */ if (bitcoin_txid_eq(&outs[i]->txid, txid)) outs[i]->depth = depth; /* Is this tx resolving an output? */ if (outs[i]->resolved) { if (bitcoin_txid_eq(&outs[i]->resolved->txid, txid)) { update_resolution_depth(outs[i], depth); } continue; } /* Otherwise, is this something we have a pending * resolution for? */ if (outs[i]->proposal && bitcoin_txid_eq(&outs[i]->txid, txid) && depth >= outs[i]->proposal->depth_required) { proposal_meets_depth(outs[i]); } } } /* BOLT #5: * * A local node: * - if it receives (or already possesses) a payment preimage for an unresolved * HTLC output that it has been offered AND for which it has committed to an * outgoing HTLC: * - MUST *resolve* the output by spending it, using the HTLC-success * transaction. * - MUST resolve the output of that HTLC-success transaction. * - otherwise: * - if the *remote node* is NOT irrevocably committed to the HTLC: * - MUST NOT *resolve* the output by spending it. *... * ## HTLC Output Handling: Remote Commitment, Remote Offers *... * A local node: * - if it receives (or already possesses) a payment preimage for an unresolved * HTLC output that it was offered AND for which it has committed to an * outgoing HTLC: * - MUST *resolve* the output by spending it to a convenient address. * - otherwise: * - if the remote node is NOT irrevocably committed to the HTLC: * - MUST NOT *resolve* the output by spending it. */ /* Master makes sure we only get told preimages once other node is committed. */ static void handle_preimage(struct tracked_output **outs, const struct preimage *preimage) { size_t i; struct sha256 sha; struct ripemd160 ripemd; u8 **witness; sha256(&sha, preimage, sizeof(*preimage)); ripemd160(&ripemd, &sha, sizeof(sha)); for (i = 0; i < tal_count(outs); i++) { struct bitcoin_tx *tx; struct bitcoin_signature sig; if (outs[i]->output_type != THEIR_HTLC) continue; if (!ripemd160_eq(&outs[i]->htlc.ripemd, &ripemd)) continue; /* Too late? */ if (outs[i]->resolved) { /* FIXME: We need a better warning method! */ status_trace("WARNING: HTLC already resolved by %s" " when we found preimage", tx_type_name(outs[i]->resolved->tx_type)); return; } /* Discard any previous resolution. Could be a timeout, * could be due to multiple identical rhashes in tx. */ outs[i]->proposal = tal_free(outs[i]->proposal); /* BOLT #5: * * * ## HTLC Output Handling: Local Commitment, Remote Offers *... * A local node: * - if it receives (or already possesses) a payment preimage * for an unresolved HTLC output that it has been offered * AND for which it has committed to an outgoing HTLC: * - MUST *resolve* the output by spending it, using the * HTLC-success transaction. */ if (outs[i]->remote_htlc_sig) { struct amount_msat htlc_amount; if (!amount_sat_to_msat(&htlc_amount, outs[i]->sat)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Overflow in output %zu %s", i, type_to_string(tmpctx, struct amount_sat, &outs[i]->sat)); tx = htlc_success_tx(outs[i], &outs[i]->txid, outs[i]->outnum, htlc_amount, to_self_delay[LOCAL], 0, keyset); set_htlc_success_fee(tx, outs[i]->remote_htlc_sig, outs[i]->wscript); hsm_sign_local_htlc_tx(tx, outs[i]->wscript, &sig); witness = bitcoin_witness_htlc_success_tx( tx, &sig, outs[i]->remote_htlc_sig, preimage, outs[i]->wscript); bitcoin_tx_input_set_witness(tx, 0, witness); propose_resolution(outs[i], tx, 0, OUR_HTLC_SUCCESS_TX); } else { enum tx_type tx_type = THEIR_HTLC_FULFILL_TO_US; /* BOLT #5: * * ## HTLC Output Handling: Remote Commitment, Remote * Offers *... * A local node: * - if it receives (or already possesses) a payment * preimage for an unresolved HTLC output that it was * offered AND for which it has committed to an * outgoing HTLC: * - MUST *resolve* the output by spending it to a * convenient address. */ tx = tx_to_us(outs[i], remote_htlc_to_us, outs[i], 0, 0, preimage, sizeof(*preimage), outs[i]->wscript, &tx_type); propose_resolution(outs[i], tx, 0, tx_type); } } } #if DEVELOPER static void memleak_remove_globals(struct htable *memtable, const tal_t *topctx) { /* memleak_scan_region is overkill if these are simple pointers to * objects which don't contain pointers, but it works. */ if (keyset) memleak_scan_region(memtable, keyset, sizeof(*keyset)); if (remote_per_commitment_point) memleak_scan_region(memtable, remote_per_commitment_point, sizeof(*remote_per_commitment_point)); if (remote_per_commitment_secret) memleak_scan_region(memtable, remote_per_commitment_secret, sizeof(*remote_per_commitment_secret)); /* top-level context args */ memleak_scan_region(memtable, topctx, 0); memleak_scan_region(memtable, missing_htlc_msgs, tal_bytelen(missing_htlc_msgs)); } static bool handle_dev_memleak(struct tracked_output **outs, const u8 *msg) { struct htable *memtable; bool found_leak; if (!fromwire_onchain_dev_memleak(msg)) return false; memtable = memleak_enter_allocations(tmpctx, msg, msg); /* Top-level context is parent of outs */ memleak_remove_globals(memtable, tal_parent(outs)); memleak_remove_referenced(memtable, outs); found_leak = dump_memleak(memtable); wire_sync_write(REQ_FD, take(towire_onchain_dev_memleak_reply(NULL, found_leak))); return true; } #else static bool handle_dev_memleak(struct tracked_output **outs, const u8 *msg) { return false; } #endif /* !DEVELOPER */ /* BOLT #5: * * A node: * - once it has broadcast a funding transaction OR sent a commitment signature * for a commitment transaction that contains an HTLC output: * - until all outputs are *irrevocably resolved*: * - MUST monitor the blockchain for transactions that spend any output that * is NOT *irrevocably resolved*. */ static void wait_for_resolved(struct tracked_output **outs) { billboard_update(outs); while (num_not_irrevocably_resolved(outs) != 0) { u8 *msg = wire_sync_read(outs, REQ_FD); struct bitcoin_txid txid; struct bitcoin_tx *tx; u32 input_num, depth, tx_blockheight; struct preimage preimage; status_trace("Got new message %s", onchain_wire_type_name(fromwire_peektype(msg))); if (fromwire_onchain_depth(msg, &txid, &depth)) tx_new_depth(outs, &txid, depth); else if (fromwire_onchain_spent(msg, msg, &tx, &input_num, &tx_blockheight)) output_spent(&outs, tx, input_num, tx_blockheight); else if (fromwire_onchain_known_preimage(msg, &preimage)) handle_preimage(outs, &preimage); else if (!handle_dev_memleak(outs, msg)) master_badmsg(-1, msg); billboard_update(outs); tal_free(msg); clean_tmpctx(); } wire_sync_write(REQ_FD, take(towire_onchain_all_irrevocably_resolved(outs))); } static void init_reply(const char *what) { /* Send init_reply first, so billboard gets credited to ONCHAIND */ wire_sync_write(REQ_FD, take(towire_onchain_init_reply(NULL))); peer_billboard(true, what); } static void handle_mutual_close(const struct bitcoin_txid *txid, struct tracked_output **outs) { init_reply("Tracking mutual close transaction"); onchain_transaction_annotate(txid, TX_CHANNEL_CLOSE); /* BOLT #5: * * A closing transaction *resolves* the funding transaction output. * * In the case of a mutual close, a node need not do anything else, as it has * already agreed to the output, which is sent to its specified `scriptpubkey` */ resolved_by_other(outs[0], txid, MUTUAL_CLOSE); wait_for_resolved(outs); } static u8 **derive_htlc_scripts(const struct htlc_stub *htlcs, enum side side) { size_t i; u8 **htlc_scripts = tal_arr(htlcs, u8 *, tal_count(htlcs)); for (i = 0; i < tal_count(htlcs); i++) { if (htlcs[i].owner == side) htlc_scripts[i] = htlc_offered_wscript(htlc_scripts, &htlcs[i].ripemd, keyset); else { /* FIXME: remove abs_locktime */ struct abs_locktime ltime; if (!blocks_to_abs_locktime(htlcs[i].cltv_expiry, <ime)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not convert cltv_expiry %u to locktime", htlcs[i].cltv_expiry); htlc_scripts[i] = htlc_received_wscript(htlc_scripts, &htlcs[i].ripemd, <ime, keyset); } } return htlc_scripts; } static size_t resolve_our_htlc_ourcommit(struct tracked_output *out, const size_t *matches, const struct htlc_stub *htlcs, u8 **htlc_scripts) { struct bitcoin_tx *tx = NULL; struct bitcoin_signature localsig; size_t i; struct amount_msat htlc_amount; u8 **witness; if (!amount_sat_to_msat(&htlc_amount, out->sat)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Overflow in our_htlc output %s", type_to_string(tmpctx, struct amount_sat, &out->sat)); assert(tal_count(matches)); /* These htlcs are all possibilities, but signature will only match * one with the correct cltv: check which that is. */ for (i = 0; i < tal_count(matches); i++) { /* BOLT #5: * * ## HTLC Output Handling: Local Commitment, Local Offers * ... * - if the commitment transaction HTLC output has *timed out* * and hasn't been *resolved*: * - MUST *resolve* the output by spending it using the * HTLC-timeout transaction. */ tx = htlc_timeout_tx(tmpctx, &out->txid, out->outnum, htlc_amount, htlcs[matches[i]].cltv_expiry, to_self_delay[LOCAL], 0, keyset); if (set_htlc_timeout_fee(tx, out->remote_htlc_sig, htlc_scripts[matches[i]])) break; } /* Since there's been trouble with this before, we go to some length * to give details here! */ if (i == tal_count(matches)) { char *cltvs, *wscripts; cltvs = tal_fmt(tmpctx, "%u", htlcs[matches[0]].cltv_expiry); wscripts = tal_hex(tmpctx, htlc_scripts[matches[0]]); for (i = 1; i < tal_count(matches); i++) { tal_append_fmt(&cltvs, "/%u", htlcs[matches[i]].cltv_expiry); tal_append_fmt(&wscripts, "/%s", tal_hex(tmpctx, htlc_scripts[matches[i]])); } status_failed(STATUS_FAIL_INTERNAL_ERROR, "No valid signature found for %zu htlc_timeout_txs" " feerate %u-%u," " last tx %s, input %s, signature %s," " cltvs %s wscripts %s", tal_count(matches), min_possible_feerate, max_possible_feerate, type_to_string(tmpctx, struct bitcoin_tx, tx), type_to_string(tmpctx, struct amount_sat, &out->sat), type_to_string(tmpctx, struct bitcoin_signature, out->remote_htlc_sig), cltvs, wscripts); } hsm_sign_local_htlc_tx(tx, htlc_scripts[matches[i]], &localsig); witness = bitcoin_witness_htlc_timeout_tx(tx, &localsig, out->remote_htlc_sig, htlc_scripts[matches[i]]); bitcoin_tx_input_set_witness(tx, 0, witness); /* Steals tx onto out */ propose_resolution_at_block(out, tx, htlcs[matches[i]].cltv_expiry, OUR_HTLC_TIMEOUT_TX); return matches[i]; } /* wscript for *received* htlcs (ie. our htlcs in their commit tx, or their * htlcs in our commit tx) includes cltv, so they must be the same for all * matching htlcs. Unless, of course, they've found a sha256 clash. */ static u32 matches_cltv(const size_t *matches, const struct htlc_stub *htlcs) { for (size_t i = 1; i < tal_count(matches); i++) { assert(matches[i] < tal_count(htlcs)); assert(htlcs[matches[i]].cltv_expiry == htlcs[matches[i-1]].cltv_expiry); } return htlcs[matches[0]].cltv_expiry; } static size_t resolve_our_htlc_theircommit(struct tracked_output *out, const size_t *matches, const struct htlc_stub *htlcs, u8 **htlc_scripts) { struct bitcoin_tx *tx; enum tx_type tx_type = OUR_HTLC_TIMEOUT_TO_US; u32 cltv_expiry = matches_cltv(matches, htlcs); /* BOLT #5: * * ## HTLC Output Handling: Remote Commitment, Local Offers * ... * * - if the commitment transaction HTLC output has *timed out* AND NOT * been *resolved*: * - MUST *resolve* the output, by spending it to a convenient * address. */ tx = tx_to_us(out, remote_htlc_to_us, out, 0, cltv_expiry, NULL, 0, htlc_scripts[matches[0]], &tx_type); propose_resolution_at_block(out, tx, cltv_expiry, tx_type); /* They're all equivalent: might as well use first one. */ return matches[0]; } /* Returns which htlcs it chose to use of matches[] */ static size_t resolve_their_htlc(struct tracked_output *out, const size_t *matches, const struct htlc_stub *htlcs, u8 **htlc_scripts) { size_t which_htlc; /* BOLT #5: * * ## HTLC Output Handling: Remote Commitment, Remote Offers *... * ### Requirements *... * If not otherwise resolved, once the HTLC output has expired, it is * considered *irrevocably resolved*. */ /* BOLT #5: * * ## HTLC Output Handling: Local Commitment, Remote Offers *... * ### Requirements *... * If not otherwise resolved, once the HTLC output has expired, it is * considered *irrevocably resolved*. */ /* The two cases are identical as far as default handling goes. * But in the remote commitment / remote offer (ie. caller is * handle_their_unilateral), htlcs which match may have different cltvs. * So wait until the worst case (largest HTLC). */ assert(tal_count(matches)); which_htlc = matches[0]; for (size_t i = 1; i < tal_count(matches); i++) { if (htlcs[matches[i]].cltv_expiry > htlcs[which_htlc].cltv_expiry) which_htlc = matches[i]; } /* If we hit timeout depth, resolve by ignoring. */ propose_resolution_at_block(out, NULL, htlcs[which_htlc].cltv_expiry, THEIR_HTLC_TIMEOUT_TO_THEM); return which_htlc; } /* Return tal_arr of htlc indexes. */ static const size_t *match_htlc_output(const tal_t *ctx, const struct bitcoin_tx *tx, unsigned int outnum, u8 **htlc_scripts) { size_t *matches = tal_arr(ctx, size_t, 0); const u8 *script = bitcoin_tx_output_get_script(tmpctx, tx, outnum); /* Must be a p2wsh output */ if (!is_p2wsh(script, NULL)) return matches; for (size_t i = 0; i < tal_count(htlc_scripts); i++) { struct sha256 sha; if (!htlc_scripts[i]) continue; sha256(&sha, htlc_scripts[i], tal_count(htlc_scripts[i])); if (memeq(script + 2, tal_count(script) - 2, &sha, sizeof(sha))) tal_arr_expand(&matches, i); } return matches; } /* They must all be in the same direction, since the scripts are different for * each dir. Unless, of course, they've found a sha256 clash. */ static enum side matches_direction(const size_t *matches, const struct htlc_stub *htlcs) { for (size_t i = 1; i < tal_count(matches); i++) { assert(matches[i] < tal_count(htlcs)); assert(htlcs[matches[i]].owner == htlcs[matches[i-1]].owner); } return htlcs[matches[0]].owner; } /* Tell master about any we didn't use, if it wants to know. */ static void note_missing_htlcs(u8 **htlc_scripts, const struct htlc_stub *htlcs, const bool *tell_if_missing, const bool *tell_immediately) { for (size_t i = 0; i < tal_count(htlcs); i++) { u8 *msg; /* Used. */ if (!htlc_scripts[i]) continue; /* Doesn't care. */ if (!tell_if_missing[i]) continue; msg = towire_onchain_missing_htlc_output(missing_htlc_msgs, &htlcs[i]); if (tell_immediately[i]) wire_sync_write(REQ_FD, take(msg)); else tal_arr_expand(&missing_htlc_msgs, msg); } } static void handle_our_unilateral(const struct bitcoin_tx *tx, u32 tx_blockheight, const struct bitcoin_txid *txid, const struct basepoints basepoints[NUM_SIDES], const struct htlc_stub *htlcs, const bool *tell_if_missing, const bool *tell_immediately, const secp256k1_ecdsa_signature *remote_htlc_sigs, struct tracked_output **outs) { u8 **htlc_scripts; u8 *local_wscript, *script[NUM_SIDES]; struct pubkey local_per_commitment_point; struct keyset *ks; size_t i; init_reply("Tracking our own unilateral close"); onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL); /* BOLT #5: * * In this case, a node discovers its *local commitment transaction*, * which *resolves* the funding transaction output. */ resolved_by_other(outs[0], txid, OUR_UNILATERAL); /* Figure out what delayed to-us output looks like */ hsm_get_per_commitment_point(&local_per_commitment_point); /* keyset is const, we need a non-const ptr to set it up */ keyset = ks = tal(tx, struct keyset); if (!derive_keyset(&local_per_commitment_point, &basepoints[LOCAL], &basepoints[REMOTE], ks)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving keyset for %"PRIu64, commit_num); status_trace("Deconstructing unilateral tx: %"PRIu64 " using keyset: " " self_revocation_key: %s" " self_delayed_payment_key: %s" " self_payment_key: %s" " other_payment_key: %s" " self_htlc_key: %s" " other_htlc_key: %s", commit_num, type_to_string(tmpctx, struct pubkey, &keyset->self_revocation_key), type_to_string(tmpctx, struct pubkey, &keyset->self_delayed_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->other_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_htlc_key), type_to_string(tmpctx, struct pubkey, &keyset->other_htlc_key)); local_wscript = to_self_wscript(tmpctx, to_self_delay[LOCAL], keyset); /* Figure out what to-us output looks like. */ script[LOCAL] = scriptpubkey_p2wsh(tmpctx, local_wscript); /* Figure out what direct to-them output looks like. */ script[REMOTE] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key); /* Calculate all the HTLC scripts so we can match them */ htlc_scripts = derive_htlc_scripts(htlcs, LOCAL); status_trace("Script to-me: %u: %s (%s)", to_self_delay[LOCAL], tal_hex(tmpctx, script[LOCAL]), tal_hex(tmpctx, local_wscript)); status_trace("Script to-them: %s", tal_hex(tmpctx, script[REMOTE])); for (i = 0; i < tx->wtx->num_outputs; i++) { status_trace("Output %zu: %s", i, tal_hex(tmpctx, bitcoin_tx_output_get_script( tmpctx, tx, i))); } for (i = 0; i < tx->wtx->num_outputs; i++) { struct tracked_output *out; const size_t *matches; size_t which_htlc; const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i); struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i); if (script[LOCAL] && scripteq(oscript, script[LOCAL])) { struct bitcoin_tx *to_us; enum tx_type tx_type = OUR_DELAYED_RETURN_TO_WALLET; /* BOLT #5: * * A node: * - upon discovering its *local commitment * transaction*: * - SHOULD spend the `to_local` output to a * convenient address. * - MUST wait until the `OP_CHECKSEQUENCEVERIFY` * delay has passed (as specified by the remote * node's `to_self_delay` field) before spending * the output. */ out = new_tracked_output(&outs, txid, tx_blockheight, OUR_UNILATERAL, i, amt, DELAYED_OUTPUT_TO_US, NULL, NULL, NULL); /* BOLT #3: * * The output is spent by a transaction with * `nSequence` field set to `to_self_delay` (which can * only be valid after that duration has passed) and * witness: * * 0 */ to_us = tx_to_us(out, delayed_payment_to_us, out, to_self_delay[LOCAL], 0, NULL, 0, local_wscript, &tx_type); /* BOLT #5: * * Note: if the output is spent (as recommended), the * output is *resolved* by the spending transaction */ propose_resolution(out, to_us, to_self_delay[LOCAL], tx_type); script[LOCAL] = NULL; continue; } if (script[REMOTE] && scripteq(oscript, script[REMOTE])) { /* BOLT #5: * * - MAY ignore the `to_remote` output. * - Note: No action is required by the local * node, as `to_remote` is considered *resolved* * by the commitment transaction itself. */ out = new_tracked_output(&outs, txid, tx_blockheight, OUR_UNILATERAL, i, amt, OUTPUT_TO_THEM, NULL, NULL, NULL); ignore_output(out); script[REMOTE] = NULL; continue; } matches = match_htlc_output(tmpctx, tx, i, htlc_scripts); /* FIXME: limp along when this happens! */ if (tal_count(matches) == 0) { onchain_transaction_annotate(txid, TX_CHANNEL_PENALTY | TX_THEIRS); status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not find resolution for output %zu", i); } if (matches_direction(matches, htlcs) == LOCAL) { /* BOLT #5: * * - MUST handle HTLCs offered by itself as specified * in [HTLC Output Handling: Local Commitment, * Local Offers] */ out = new_tracked_output(&outs, txid, tx_blockheight, OUR_UNILATERAL, i, amt, OUR_HTLC, NULL, NULL, remote_htlc_sigs); /* Tells us which htlc to use */ which_htlc = resolve_our_htlc_ourcommit(out, matches, htlcs, htlc_scripts); } else { out = new_tracked_output(&outs, txid, tx_blockheight, OUR_UNILATERAL, i, amt, THEIR_HTLC, NULL, NULL, remote_htlc_sigs); /* BOLT #5: * * - MUST handle HTLCs offered by the remote node * as specified in [HTLC Output Handling: Local * Commitment, Remote Offers] */ /* Tells us which htlc to use */ which_htlc = resolve_their_htlc(out, matches, htlcs, htlc_scripts); } out->htlc = htlcs[which_htlc]; out->wscript = tal_steal(out, htlc_scripts[which_htlc]); /* Each of these consumes one HTLC signature */ remote_htlc_sigs++; /* We've matched this HTLC, can't do again. */ htlc_scripts[which_htlc] = NULL; } note_missing_htlcs(htlc_scripts, htlcs, tell_if_missing, tell_immediately); wait_for_resolved(outs); } /* We produce individual penalty txs. It's less efficient, but avoids them * using HTLC txs to block our penalties for long enough to pass the CSV * delay */ static void steal_to_them_output(struct tracked_output *out) { u8 *wscript; struct bitcoin_tx *tx; enum tx_type tx_type = OUR_PENALTY_TX; /* BOLT #3: * * If a revoked commitment transaction is published, the other party * can spend this output immediately with the following witness: * * 1 */ wscript = bitcoin_wscript_to_local(tmpctx, to_self_delay[REMOTE], &keyset->self_revocation_key, &keyset->self_delayed_payment_key); tx = tx_to_us(tmpctx, penalty_to_us, out, 0xFFFFFFFF, 0, &ONE, sizeof(ONE), wscript, &tx_type); propose_resolution(out, tx, 0, tx_type); } static void steal_htlc(struct tracked_output *out) { struct bitcoin_tx *tx; enum tx_type tx_type = OUR_PENALTY_TX; u8 der[PUBKEY_CMPR_LEN]; /* BOLT #3: * * If a revoked commitment transaction is published, the remote node can * spend this output immediately with the following witness: * * */ pubkey_to_der(der, &keyset->self_revocation_key); tx = tx_to_us(out, penalty_to_us, out, 0xFFFFFFFF, 0, der, sizeof(der), out->wscript, &tx_type); propose_resolution(out, tx, 0, tx_type); } /* BOLT #5: * * If any node tries to cheat by broadcasting an outdated commitment * transaction (any previous commitment transaction besides the most current * one), the other node in the channel can use its revocation private key to * claim all the funds from the channel's original funding transaction. */ static void handle_their_cheat(const struct bitcoin_tx *tx, const struct bitcoin_txid *txid, u32 tx_blockheight, const struct secret *revocation_preimage, const struct basepoints basepoints[NUM_SIDES], const struct htlc_stub *htlcs, const bool *tell_if_missing, const bool *tell_immediately, struct tracked_output **outs) { u8 **htlc_scripts; u8 *remote_wscript, *script[NUM_SIDES]; struct keyset *ks; struct pubkey *k; size_t i; init_reply("Tracking their illegal close: taking all funds"); onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_CHANNEL_CHEAT | TX_THEIRS); /* BOLT #5: * * Once a node discovers a commitment transaction for which *it* has a * revocation private key, the funding transaction output is *resolved*. */ resolved_by_other(outs[0], txid, THEIR_REVOKED_UNILATERAL); /* FIXME: Types. */ BUILD_ASSERT(sizeof(struct secret) == sizeof(*revocation_preimage)); remote_per_commitment_secret = tal_dup(tx, struct secret, (struct secret *) revocation_preimage); /* Need tmpvar for non-const. */ remote_per_commitment_point = k = tal(tx, struct pubkey); if (!pubkey_from_secret(remote_per_commitment_secret, k)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Failed derive from per_commitment_secret %s", type_to_string(tmpctx, struct secret, remote_per_commitment_secret)); status_trace("Deriving keyset %"PRIu64 ": per_commit_point=%s" " self_payment_basepoint=%s" " other_payment_basepoint=%s" " self_htlc_basepoint=%s" " other_htlc_basepoint=%s" " self_delayed_basepoint=%s" " other_revocation_basepoint=%s", commit_num, type_to_string(tmpctx, struct pubkey, remote_per_commitment_point), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].payment), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].payment), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].htlc), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].htlc), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].delayed_payment), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].revocation)); /* keyset is const, we need a non-const ptr to set it up */ keyset = ks = tal(tx, struct keyset); if (!derive_keyset(remote_per_commitment_point, &basepoints[REMOTE], &basepoints[LOCAL], ks)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving keyset for %"PRIu64, commit_num); status_trace("Deconstructing revoked unilateral tx: %"PRIu64 " using keyset: " " self_revocation_key: %s" " self_delayed_payment_key: %s" " self_payment_key: %s" " other_payment_key: %s" " self_htlc_key: %s" " other_htlc_key: %s", commit_num, type_to_string(tmpctx, struct pubkey, &keyset->self_revocation_key), type_to_string(tmpctx, struct pubkey, &keyset->self_delayed_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->other_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_htlc_key), type_to_string(tmpctx, struct pubkey, &keyset->other_htlc_key)); remote_wscript = to_self_wscript(tmpctx, to_self_delay[REMOTE], keyset); /* Figure out what to-them output looks like. */ script[REMOTE] = scriptpubkey_p2wsh(tmpctx, remote_wscript); /* Figure out what direct to-us output looks like. */ script[LOCAL] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key); /* Calculate all the HTLC scripts so we can match them */ htlc_scripts = derive_htlc_scripts(htlcs, REMOTE); status_trace("Script to-them: %u: %s (%s)", to_self_delay[REMOTE], tal_hex(tmpctx, script[REMOTE]), tal_hex(tmpctx, remote_wscript)); status_trace("Script to-me: %s", tal_hex(tmpctx, script[LOCAL])); for (i = 0; i < tx->wtx->num_outputs; i++) { status_trace("Output %zu: %s", i, tal_hex(tmpctx, bitcoin_tx_output_get_script( tmpctx, tx, i))); } for (i = 0; i < tx->wtx->num_outputs; i++) { struct tracked_output *out; const size_t *matches; size_t which_htlc; const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i); struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i); if (script[LOCAL] && scripteq(oscript, script[LOCAL])) { /* BOLT #5: * * - MAY take no action regarding the _local node's * main output_, as this is a simple P2WPKH output * to itself. * - Note: this output is considered *resolved* by * the commitment transaction itself. */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_REVOKED_UNILATERAL, i, amt, OUTPUT_TO_US, NULL, NULL, NULL); ignore_output(out); /* Tell the master that it will want to add * this UTXO to its outputs */ wire_sync_write(REQ_FD, towire_onchain_add_utxo( tmpctx, txid, i, remote_per_commitment_point, amt, tx_blockheight, script[LOCAL])); script[LOCAL] = NULL; continue; } if (script[REMOTE] && scripteq(oscript, script[REMOTE])) { /* BOLT #5: * * - MUST *resolve* the _remote node's main output_ by * spending it using the revocation private key. */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_REVOKED_UNILATERAL, i, amt, DELAYED_OUTPUT_TO_THEM, NULL, NULL, NULL); steal_to_them_output(out); script[REMOTE] = NULL; continue; } matches = match_htlc_output(tmpctx, tx, i, htlc_scripts); if (tal_count(matches) == 0) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not find resolution for output %zu", i); /* In this case, we don't care which HTLC we choose; so pick first one */ which_htlc = matches[0]; if (matches_direction(matches, htlcs) == LOCAL) { /* BOLT #5: * * - MUST *resolve* the _local node's offered HTLCs_ in one of three ways: * * spend the *commitment tx* using the payment revocation private key. * * spend the *commitment tx* once the HTLC timeout has passed. * * spend the *HTLC-success tx*, if the remote node has published it. */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_REVOKED_UNILATERAL, i, amt, OUR_HTLC, &htlcs[which_htlc], htlc_scripts[which_htlc], NULL); steal_htlc(out); } else { out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_REVOKED_UNILATERAL, i, amt, THEIR_HTLC, &htlcs[which_htlc], htlc_scripts[which_htlc], NULL); /* BOLT #5: * * - MUST *resolve* the _remote node's offered HTLCs_ in one of three ways: * * spend the *commitment tx* using the payment revocation private key. * * spend the *commitment tx* using the payment preimage (if known). * * spend the *HTLC-timeout tx*, if the remote node has published it. */ steal_htlc(out); } htlc_scripts[which_htlc] = NULL; } note_missing_htlcs(htlc_scripts, htlcs, tell_if_missing, tell_immediately); wait_for_resolved(outs); } static void handle_their_unilateral(const struct bitcoin_tx *tx, u32 tx_blockheight, const struct bitcoin_txid *txid, const struct pubkey *this_remote_per_commitment_point, const struct basepoints basepoints[NUM_SIDES], const struct htlc_stub *htlcs, const bool *tell_if_missing, const bool *tell_immediately, struct tracked_output **outs) { u8 **htlc_scripts; u8 *remote_wscript, *script[NUM_SIDES]; struct keyset *ks; size_t i; init_reply("Tracking their unilateral close"); onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_THEIRS); /* HSM can't derive this. */ remote_per_commitment_point = this_remote_per_commitment_point; /* BOLT #5: * * # Unilateral Close Handling: Remote Commitment Transaction * * The *remote node's* commitment transaction *resolves* the funding * transaction output. * * There are no delays constraining node behavior in this case, so * it's simpler for a node to handle than the case in which it * discovers its local commitment transaction (see [Unilateral Close * Handling: Local Commitment Transaction] */ resolved_by_other(outs[0], txid, THEIR_UNILATERAL); status_trace("Deriving keyset %"PRIu64 ": per_commit_point=%s" " self_payment_basepoint=%s" " other_payment_basepoint=%s" " self_htlc_basepoint=%s" " other_htlc_basepoint=%s" " self_delayed_basepoint=%s" " other_revocation_basepoint=%s", commit_num, type_to_string(tmpctx, struct pubkey, remote_per_commitment_point), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].payment), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].payment), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].htlc), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].htlc), type_to_string(tmpctx, struct pubkey, &basepoints[REMOTE].delayed_payment), type_to_string(tmpctx, struct pubkey, &basepoints[LOCAL].revocation)); /* keyset is const, we need a non-const ptr to set it up */ keyset = ks = tal(tx, struct keyset); if (!derive_keyset(remote_per_commitment_point, &basepoints[REMOTE], &basepoints[LOCAL], ks)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving keyset for %"PRIu64, commit_num); status_trace("Deconstructing unilateral tx: %"PRIu64 " using keyset: " " self_revocation_key: %s" " self_delayed_payment_key: %s" " self_payment_key: %s" " other_payment_key: %s" " self_htlc_key: %s" " other_htlc_key: %s", commit_num, type_to_string(tmpctx, struct pubkey, &keyset->self_revocation_key), type_to_string(tmpctx, struct pubkey, &keyset->self_delayed_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->other_payment_key), type_to_string(tmpctx, struct pubkey, &keyset->self_htlc_key), type_to_string(tmpctx, struct pubkey, &keyset->other_htlc_key)); remote_wscript = to_self_wscript(tmpctx, to_self_delay[REMOTE], keyset); /* Figure out what to-them output looks like. */ script[REMOTE] = scriptpubkey_p2wsh(tmpctx, remote_wscript); /* Figure out what direct to-us output looks like. */ script[LOCAL] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key); /* Calculate all the HTLC scripts so we can match them */ htlc_scripts = derive_htlc_scripts(htlcs, REMOTE); status_trace("Script to-them: %u: %s (%s)", to_self_delay[REMOTE], tal_hex(tmpctx, script[REMOTE]), tal_hex(tmpctx, remote_wscript)); status_trace("Script to-me: %s", tal_hex(tmpctx, script[LOCAL])); for (i = 0; i < tx->wtx->num_outputs; i++) { status_trace("Output %zu: %s", i, tal_hex(tmpctx, bitcoin_tx_output_get_script( tmpctx, tx, i))); } for (i = 0; i < tx->wtx->num_outputs; i++) { struct tracked_output *out; const size_t *matches; size_t which_htlc; const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i); struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i); if (script[LOCAL] && scripteq(oscript, script[LOCAL])) { /* BOLT #5: * * - MAY take no action in regard to the associated * `to_remote`, which is simply a P2WPKH output to * the *local node*. * - Note: `to_remote` is considered *resolved* by the * commitment transaction itself. */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_UNILATERAL, i, amt, OUTPUT_TO_US, NULL, NULL, NULL); ignore_output(out); /* Tell the master that it will want to add * this UTXO to its outputs */ wire_sync_write(REQ_FD, towire_onchain_add_utxo( tmpctx, txid, i, remote_per_commitment_point, amt, tx_blockheight, script[LOCAL])); script[LOCAL] = NULL; continue; } if (script[REMOTE] && scripteq(oscript, script[REMOTE])) { /* BOLT #5: * * - MAY take no action in regard to the associated * `to_local`, which is a payment output to the *remote * node*. * - Note: `to_local` is considered *resolved* by the * commitment transaction itself. */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_UNILATERAL, i, amt, DELAYED_OUTPUT_TO_THEM, NULL, NULL, NULL); ignore_output(out); continue; } matches = match_htlc_output(tmpctx, tx, i, htlc_scripts); if (tal_count(matches) == 0) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Could not find resolution for output %zu", i); if (matches_direction(matches, htlcs) == LOCAL) { /* BOLT #5: * * - MUST handle HTLCs offered by itself as specified in * [HTLC Output Handling: Remote Commitment, * Local Offers] */ out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_UNILATERAL, i, amt, OUR_HTLC, NULL, NULL, NULL); which_htlc = resolve_our_htlc_theircommit(out, matches, htlcs, htlc_scripts); } else { out = new_tracked_output(&outs, txid, tx_blockheight, THEIR_UNILATERAL, i, amt, THEIR_HTLC, NULL, NULL, NULL); /* BOLT #5: * * - MUST handle HTLCs offered by the remote node as * specified in [HTLC Output Handling: Remote * Commitment, Remote Offers] */ which_htlc = resolve_their_htlc(out, matches, htlcs, htlc_scripts); } out->htlc = htlcs[which_htlc]; out->wscript = tal_steal(out, htlc_scripts[which_htlc]); htlc_scripts[which_htlc] = NULL; } note_missing_htlcs(htlc_scripts, htlcs, tell_if_missing, tell_immediately); wait_for_resolved(outs); } static void handle_unknown_commitment(const struct bitcoin_tx *tx, u32 tx_blockheight, u64 commit_num, const struct bitcoin_txid *txid, const struct pubkey *possible_remote_per_commitment_point, const struct basepoints basepoints[NUM_SIDES], const struct htlc_stub *htlcs, const bool *tell_if_missing, struct tracked_output **outs) { struct keyset *ks; int to_us_output = -1; u8 *local_script; onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_THEIRS); resolved_by_other(outs[0], txid, UNKNOWN_UNILATERAL); if (!possible_remote_per_commitment_point) goto search_done; keyset = ks = tal(tx, struct keyset); if (!derive_keyset(possible_remote_per_commitment_point, &basepoints[REMOTE], &basepoints[LOCAL], ks)) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Deriving keyset for possible_remote_per_commitment_point %s", type_to_string(tmpctx, struct pubkey, possible_remote_per_commitment_point)); local_script = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key); for (size_t i = 0; i < tx->wtx->num_outputs; i++) { struct tracked_output *out; const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i); struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i); if (local_script && scripteq(oscript, local_script)) { /* BOLT #5: * * - MAY take no action in regard to the associated * `to_remote`, which is simply a P2WPKH output to * the *local node*. * - Note: `to_remote` is considered *resolved* by the * commitment transaction itself. */ out = new_tracked_output(&outs, txid, tx_blockheight, UNKNOWN_UNILATERAL, i, amt, OUTPUT_TO_US, NULL, NULL, NULL); ignore_output(out); /* Tell the master that it will want to add * this UTXO to its outputs */ wire_sync_write(REQ_FD, towire_onchain_add_utxo( tmpctx, txid, i, possible_remote_per_commitment_point, amt, tx_blockheight, local_script)); local_script = NULL; to_us_output = i; } } search_done: if (to_us_output == -1) { status_broken("FUNDS LOST. Unknown commitment #%"PRIu64"!", commit_num); init_reply("ERROR: FUNDS LOST. Unknown commitment!"); } else { status_broken("ERROR: Unknown commitment #%"PRIu64 ", recovering our funds!", commit_num); init_reply("ERROR: Unknown commitment, recovering our funds!"); } /* Tell master to give up on HTLCs immediately. */ for (size_t i = 0; i < tal_count(htlcs); i++) { u8 *msg; if (!tell_if_missing[i]) continue; msg = towire_onchain_missing_htlc_output(NULL, &htlcs[i]); wire_sync_write(REQ_FD, take(msg)); } wait_for_resolved(outs); } int main(int argc, char *argv[]) { setup_locale(); const tal_t *ctx = tal(NULL, char); u8 *msg; struct pubkey remote_per_commit_point, old_remote_per_commit_point; enum side funder; struct basepoints basepoints[NUM_SIDES]; struct shachain shachain; struct bitcoin_tx *tx; struct tracked_output **outs; struct bitcoin_txid our_broadcast_txid, txid, tmptxid; secp256k1_ecdsa_signature *remote_htlc_sigs; struct amount_sat funding; u64 num_htlcs; u8 *scriptpubkey[NUM_SIDES]; struct htlc_stub *htlcs; bool *tell_if_missing, *tell_immediately; u32 tx_blockheight; struct pubkey *possible_remote_per_commitment_point; subdaemon_setup(argc, argv); status_setup_sync(REQ_FD); missing_htlc_msgs = tal_arr(ctx, u8 *, 0); msg = wire_sync_read(tmpctx, REQ_FD); if (!fromwire_onchain_init(tmpctx, msg, &shachain, &funding, &old_remote_per_commit_point, &remote_per_commit_point, &to_self_delay[LOCAL], &to_self_delay[REMOTE], &feerate_per_kw, &dust_limit, &our_broadcast_txid, &scriptpubkey[LOCAL], &scriptpubkey[REMOTE], &our_wallet_pubkey, &funder, &basepoints[LOCAL], &basepoints[REMOTE], &tx, &tx_blockheight, &reasonable_depth, &remote_htlc_sigs, &num_htlcs, &min_possible_feerate, &max_possible_feerate, &possible_remote_per_commitment_point)) { master_badmsg(WIRE_ONCHAIN_INIT, msg); } status_trace("feerate_per_kw = %u", feerate_per_kw); bitcoin_txid(tx, &txid); /* We need to keep tx around, but there's only one: not really a leak */ tal_steal(ctx, notleak(tx)); /* FIXME: Filter as we go, don't load them all into mem! */ htlcs = tal_arr(tmpctx, struct htlc_stub, num_htlcs); tell_if_missing = tal_arr(htlcs, bool, num_htlcs); tell_immediately = tal_arr(htlcs, bool, num_htlcs); if (!htlcs || !tell_if_missing || !tell_immediately) status_failed(STATUS_FAIL_INTERNAL_ERROR, "Can't allocate %"PRIu64" htlcs", num_htlcs); for (u64 i = 0; i < num_htlcs; i++) { msg = wire_sync_read(tmpctx, REQ_FD); if (!fromwire_onchain_htlc(msg, &htlcs[i], &tell_if_missing[i], &tell_immediately[i])) master_badmsg(WIRE_ONCHAIN_HTLC, msg); } outs = tal_arr(ctx, struct tracked_output *, 0); bitcoin_tx_input_get_txid(tx, 0, &tmptxid); new_tracked_output(&outs, &tmptxid, 0, /* We don't care about funding blockheight */ FUNDING_TRANSACTION, tx->wtx->inputs[0].index, funding, FUNDING_OUTPUT, NULL, NULL, NULL); status_trace("Remote per-commit point: %s", type_to_string(tmpctx, struct pubkey, &remote_per_commit_point)); status_trace("Old remote per-commit point: %s", type_to_string(tmpctx, struct pubkey, &old_remote_per_commit_point)); /* BOLT #5: * * There are three ways a channel can end: * * 1. The good way (*mutual close*): at some point the local and * remote nodes agree to close the channel. They generate a *closing * transaction* (which is similar to a commitment transaction, but * without any pending payments) and publish it on the blockchain (see * [BOLT #2: Channel Close](02-peer-protocol.md#channel-close)). */ if (is_mutual_close(tx, scriptpubkey[LOCAL], scriptpubkey[REMOTE])) handle_mutual_close(&txid, outs); else { /* BOLT #5: * * 2. The bad way (*unilateral close*): something goes wrong, * possibly without evil intent on either side. Perhaps one * party crashed, for instance. One side publishes its * *latest commitment transaction*. */ struct secret revocation_preimage; commit_num = unmask_commit_number(tx, funder, &basepoints[LOCAL].payment, &basepoints[REMOTE].payment); status_trace("commitnum = %"PRIu64 ", revocations_received = %"PRIu64, commit_num, revocations_received(&shachain)); if (is_local_commitment(&txid, &our_broadcast_txid)) handle_our_unilateral(tx, tx_blockheight, &txid, basepoints, htlcs, tell_if_missing, tell_immediately, remote_htlc_sigs, outs); /* BOLT #5: * * 3. The ugly way (*revoked transaction close*): one of the * parties deliberately tries to cheat, by publishing an * *outdated commitment transaction* (presumably, a prior * version, which is more in its favor). */ else if (shachain_get_secret(&shachain, commit_num, &revocation_preimage)) { handle_their_cheat(tx, &txid, tx_blockheight, &revocation_preimage, basepoints, htlcs, tell_if_missing, tell_immediately, outs); /* BOLT #5: * * There may be more than one valid, *unrevoked* commitment * transaction after a signature has been received via * `commitment_signed` and before the corresponding * `revoke_and_ack`. As such, either commitment may serve as * the *remote node's* commitment transaction; hence, the * local node is required to handle both. */ } else if (commit_num == revocations_received(&shachain)) { status_trace("Their unilateral tx, old commit point"); handle_their_unilateral(tx, tx_blockheight, &txid, &old_remote_per_commit_point, basepoints, htlcs, tell_if_missing, tell_immediately, outs); } else if (commit_num == revocations_received(&shachain) + 1) { status_trace("Their unilateral tx, new commit point"); handle_their_unilateral(tx, tx_blockheight, &txid, &remote_per_commit_point, basepoints, htlcs, tell_if_missing, tell_immediately, outs); } else { handle_unknown_commitment(tx, tx_blockheight, commit_num, &txid, possible_remote_per_commitment_point, basepoints, htlcs, tell_if_missing, outs); } } /* We're done! */ tal_free(ctx); daemon_shutdown(); return 0; }