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This uses `fundpsbt` and similar to simulate the txprepare command. It has one difference (when complete), in that it those reservations are now timed and don't get reset on restart. It also doesn't have the restriction that `all` can only be used with no other output, as I didn't realize that when I implemented it! Note that change is now inserted in a random position, not sorted into BIP69 order. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>bump-pyln-proto
Rusty Russell
4 years ago
2 changed files with 313 additions and 1 deletions
@ -0,0 +1,305 @@ |
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#include <bitcoin/chainparams.h> |
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#include <bitcoin/feerate.h> |
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#include <bitcoin/psbt.h> |
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#include <bitcoin/script.h> |
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#include <ccan/array_size/array_size.h> |
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#include <ccan/cast/cast.h> |
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#include <ccan/json_out/json_out.h> |
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#include <ccan/tal/str/str.h> |
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#include <common/addr.h> |
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#include <common/amount.h> |
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#include <common/features.h> |
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#include <common/json_stream.h> |
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#include <common/json_tok.h> |
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#include <common/pseudorand.h> |
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#include <common/type_to_string.h> |
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#include <common/utils.h> |
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#include <plugins/libplugin.h> |
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struct tx_output { |
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struct amount_sat amount; |
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const u8 *script; |
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}; |
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struct txprepare { |
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struct tx_output *outputs; |
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struct amount_sat output_total; |
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/* Weight for core + outputs */ |
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size_t weight; |
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/* Which output is 'all', or -1 (not counted in output_total!) */ |
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int all_output_idx; |
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/* Once we have a PSBT, it goes here. */ |
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struct wally_psbt *psbt; |
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u32 feerate; |
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/* Once we have reserved all the inputs, this is set. */ |
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struct amount_sat change_amount; |
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}; |
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static struct wally_psbt *json_tok_psbt(const tal_t *ctx, |
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const char *buffer, |
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const jsmntok_t *tok) |
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{ |
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return psbt_from_b64(ctx, buffer + tok->start, tok->end - tok->start); |
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} |
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static struct command_result *param_outputs(struct command *cmd, |
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const char *name, |
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const char *buffer, |
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const jsmntok_t *tok, |
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struct txprepare *txp) |
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{ |
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size_t i; |
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const jsmntok_t *t; |
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txp->outputs = tal_arr(txp, struct tx_output, tok->size); |
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txp->output_total = AMOUNT_SAT(0); |
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txp->all_output_idx = -1; |
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/* We assume < 253 inputs, and if we're wrong, the fee
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* difference is trivial. */ |
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txp->weight = bitcoin_tx_core_weight(1, tal_count(txp->outputs)); |
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json_for_each_arr(i, t, tok) { |
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enum address_parse_result res; |
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struct tx_output *out = &txp->outputs[i]; |
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/* output format: {destination: amount} */ |
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if (t->type != JSMN_OBJECT) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"The output format must be " |
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"{destination: amount}"); |
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res = json_to_address_scriptpubkey(cmd, |
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chainparams, |
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buffer, &t[1], |
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&out->script); |
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if (res == ADDRESS_PARSE_UNRECOGNIZED) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"Could not parse destination address"); |
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else if (res == ADDRESS_PARSE_WRONG_NETWORK) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"Destination address is not on network %s", |
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chainparams->network_name); |
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if (!json_to_sat_or_all(buffer, &t[2], &out->amount)) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"'%.*s' is a invalid satoshi amount", |
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t[2].end - t[2].start, |
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buffer + t[2].start); |
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if (amount_sat_eq(out->amount, AMOUNT_SAT(-1ULL))) { |
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if (txp->all_output_idx != -1) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"Cannot use 'all' in" |
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" two outputs"); |
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txp->all_output_idx = i; |
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} else { |
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if (!amount_sat_add(&txp->output_total, |
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txp->output_total, |
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out->amount)) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"Output amount overflow"); |
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} |
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txp->weight += bitcoin_tx_output_weight(tal_bytelen(out->script)); |
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} |
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return NULL; |
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} |
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static struct command_result *finish_txprepare(struct command *cmd, |
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struct txprepare *txp) |
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{ |
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struct json_stream *out; |
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struct wally_tx *tx; |
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struct bitcoin_txid txid; |
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/* Add the outputs they gave us */ |
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for (size_t i = 0; i < tal_count(txp->outputs); i++) { |
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struct wally_tx_output *out; |
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out = wally_tx_output(txp->outputs[i].script, |
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txp->outputs[i].amount); |
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if (!out) |
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return command_fail(cmd, JSONRPC2_INVALID_PARAMS, |
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"Invalid output %zi (%s:%s)", i, |
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tal_hex(tmpctx, |
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txp->outputs[i].script), |
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type_to_string(tmpctx, |
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struct amount_sat, |
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&txp->outputs[i].amount)); |
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psbt_add_output(txp->psbt, out, i); |
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} |
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psbt_txid(txp->psbt, &txid, &tx); |
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out = jsonrpc_stream_success(cmd); |
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json_add_hex_talarr(out, "unsigned_tx", linearize_wtx(tmpctx, tx)); |
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json_add_txid(out, "txid", &txid); |
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return command_finished(cmd, out); |
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} |
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/* newaddr has given us a change address. */ |
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static struct command_result *newaddr_done(struct command *cmd, |
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const char *buf, |
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const jsmntok_t *result, |
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struct txprepare *txp) |
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{ |
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size_t num = tal_count(txp->outputs), pos; |
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const jsmntok_t *addr = json_get_member(buf, result, "bech32"); |
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/* Insert change in random position in outputs */ |
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tal_resize(&txp->outputs, num+1); |
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pos = pseudorand(num+1); |
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memmove(txp->outputs + pos + 1, |
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txp->outputs + pos, |
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sizeof(txp->outputs[0]) * (num - pos)); |
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txp->outputs[pos].amount = txp->change_amount; |
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if (json_to_address_scriptpubkey(txp, chainparams, buf, addr, |
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&txp->outputs[pos].script) |
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!= ADDRESS_PARSE_SUCCESS) { |
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return command_fail(cmd, LIGHTNINGD, |
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"Change address '%.*s' unparsable?", |
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addr->end - addr->start, |
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buf + addr->start); |
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} |
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return finish_txprepare(cmd, txp); |
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} |
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static bool resolve_all_output_amount(struct txprepare *txp, |
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struct amount_sat excess) |
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{ |
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if (!amount_sat_greater_eq(excess, chainparams->dust_limit)) |
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return false; |
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assert(amount_sat_eq(txp->outputs[txp->all_output_idx].amount, |
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AMOUNT_SAT(-1ULL))); |
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txp->outputs[txp->all_output_idx].amount = excess; |
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return true; |
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} |
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/* fundpsbt gets a viable PSBT for us. */ |
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static struct command_result *fundpsbt_done(struct command *cmd, |
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const char *buf, |
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const jsmntok_t *result, |
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struct txprepare *txp) |
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{ |
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const jsmntok_t *psbttok; |
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struct out_req *req; |
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struct amount_sat excess; |
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psbttok = json_get_member(buf, result, "psbt"); |
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txp->psbt = json_tok_psbt(txp, buf, psbttok); |
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if (!txp->psbt) |
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return command_fail(cmd, LIGHTNINGD, |
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"Unparsable psbt: '%.*s'", |
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psbttok->end - psbttok->start, |
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buf + psbttok->start); |
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if (!json_to_number(buf, json_get_member(buf, result, "feerate_per_kw"), |
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&txp->feerate)) |
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return command_fail(cmd, LIGHTNINGD, |
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"Unparsable feerate_per_kw: '%.*s'", |
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result->end - result->start, |
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buf + result->start); |
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if (!json_to_sat(buf, json_get_member(buf, result, "excess_msat"), |
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&excess)) |
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return command_fail(cmd, LIGHTNINGD, |
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"Unparsable excess_msat: '%.*s'", |
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result->end - result->start, |
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buf + result->start); |
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/* If we have an "all" output, now we can derive its value: excess
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* in this case will be total value after inputs paid for themselves. */ |
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if (txp->all_output_idx != -1) { |
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if (!resolve_all_output_amount(txp, excess)) |
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return command_fail(cmd, FUND_CANNOT_AFFORD, |
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"Insufficient funds to make" |
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" 'all' output"); |
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/* Never produce change if they asked for all */ |
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excess = AMOUNT_SAT(0); |
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} |
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/* So, do we need change? */ |
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txp->change_amount = change_amount(excess, txp->feerate); |
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if (amount_sat_eq(txp->change_amount, AMOUNT_SAT(0))) |
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return finish_txprepare(cmd, txp); |
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/* Ask for a change address */ |
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req = jsonrpc_request_start(cmd->plugin, cmd, |
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"newaddr", |
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newaddr_done, |
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/* It would be nice to unreserve inputs,
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* but probably won't happen. */ |
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forward_error, |
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txp); |
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return send_outreq(cmd->plugin, req); |
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} |
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static struct command_result *json_txprepare(struct command *cmd, |
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const char *buffer, |
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const jsmntok_t *params) |
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{ |
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struct txprepare *txp = tal(cmd, struct txprepare); |
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struct out_req *req; |
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const char *feerate; |
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unsigned int *minconf; |
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const jsmntok_t *utxos; |
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if (!param(cmd, buffer, params, |
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p_req("outputs", param_outputs, txp), |
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p_opt("feerate", param_string, &feerate), |
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p_opt_def("minconf", param_number, &minconf, 1), |
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p_opt("utxos", param_tok, &utxos), |
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NULL)) |
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return command_param_failed(); |
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/* p_opt_def doesn't compile with strings... */ |
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if (!feerate) |
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feerate = "opening"; |
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if (utxos) { |
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return command_done_err(cmd, |
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JSONRPC2_INVALID_PARAMS, |
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"FIXME: utxos not implemented!", |
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NULL); |
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} |
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/* Otherwise, we can now try to gather UTXOs. */ |
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req = jsonrpc_request_start(cmd->plugin, cmd, "fundpsbt", |
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fundpsbt_done, forward_error, |
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txp); |
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if (txp->all_output_idx == -1) |
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json_add_amount_sat_only(req->js, "satoshi", txp->output_total); |
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else |
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json_add_string(req->js, "satoshi", "all"); |
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json_add_u32(req->js, "startweight", txp->weight); |
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/* Pass through feerate and minconf */ |
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json_add_string(req->js, "feerate", feerate); |
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json_add_u32(req->js, "minconf", *minconf); |
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return send_outreq(cmd->plugin, req); |
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} |
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static const struct plugin_command commands[] = { |
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{ |
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"newtxprepare", |
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"bitcoin", |
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"Create a transaction, with option to spend in future (either txsend and txdiscard)", |
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"Create an unsigned transaction paying {outputs} with optional {feerate}, {minconf} and {utxos}", |
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json_txprepare |
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}, |
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}; |
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int main(int argc, char *argv[]) |
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{ |
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setup_locale(); |
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plugin_main(argv, NULL, PLUGIN_RESTARTABLE, true, NULL, commands, |
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ARRAY_SIZE(commands), NULL, 0, NULL, 0, NULL); |
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} |
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