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/* Code to talk to bitcoind to watch for various events.
*
* Here's what we want to know:
*
* - An anchor tx:
* - Reached given depth
* - Times out.
* - Is unspent after reaching given depth.
*
* - Our own commitment tx:
* - Reached a given depth.
*
* - HTLC spend tx:
* - Reached a given depth.
*
* - Anchor tx output:
* - Is spent by their current tx.
* - Is spent by a revoked tx.
*
* - Commitment tx HTLC outputs:
* - HTLC timed out
* - HTLC spent
*
* We do this by adding the P2SH address to the wallet, and then querying
* that using listtransactions.
*
* WE ASSUME NO MALLEABILITY! This requires segregated witness.
*/
#include "bitcoin/script.h"
#include "bitcoin/tx.h"
#include "bitcoind.h"
#include "lightningd.h"
#include "log.h"
#include "peer.h"
#include "timeout.h"
#include "watch.h"
#include <ccan/hash/hash.h>
#include <ccan/structeq/structeq.h>
const struct txwatch_output *txowatch_keyof(const struct txowatch *w)
{
return &w->out;
}
size_t txo_hash(const struct txwatch_output *out)
{
return hash(&out->txid, 1, out->index);
}
bool txowatch_eq(const struct txowatch *w, const struct txwatch_output *out)
{
return structeq(&w->out.txid, &out->txid)
&& w->out.index == out->index;
}
static void destroy_txowatch(struct txowatch *w)
{
txowatch_hash_del(&w->peer->dstate->txowatches, w);
}
/* Watch a txo. */
static void insert_txo_watch(const tal_t *ctx,
struct peer *peer,
const struct sha256_double *txid,
unsigned int txout,
void (*cb)(struct peer *peer,
const struct bitcoin_tx *tx,
void *cbdata),
void *cbdata)
{
struct txowatch *w = tal(ctx, struct txowatch);
w->out.txid = *txid;
w->out.index = txout;
w->peer = peer;
w->cb = cb;
w->cbdata = cbdata;
txowatch_hash_add(&w->peer->dstate->txowatches, w);
tal_add_destructor(w, destroy_txowatch);
}
const struct sha256_double *txwatch_keyof(const struct txwatch *w)
{
return &w->txid;
}
size_t txid_hash(const struct sha256_double *txid)
{
return hash(txid->sha.u.u8, sizeof(txid->sha.u.u8), 0);
}
bool txwatch_eq(const struct txwatch *w, const struct sha256_double *txid)
{
return structeq(&w->txid, txid);
}
static void destroy_txwatch(struct txwatch *w)
{
txwatch_hash_del(&w->dstate->txwatches, w);
}
static struct txwatch *insert_txwatch(const tal_t *ctx,
struct peer *peer,
const struct sha256_double *txid,
void (*cb)(struct peer *, int,
const struct sha256_double *,
void *),
void *cbdata)
{
struct txwatch *w;
/* We could have a null-watch on it because we saw it spend a TXO */
w = txwatch_hash_get(&peer->dstate->txwatches, txid);
if (w) {
assert(!w->cb);
tal_free(w);
}
w = tal(ctx, struct txwatch);
w->depth = 0;
w->txid = *txid;
w->dstate = peer->dstate;
w->peer = peer;
w->cb = cb;
w->cbdata = cbdata;
txwatch_hash_add(&w->dstate->txwatches, w);
tal_add_destructor(w, destroy_txwatch);
return w;
}
/* This just serves to avoid us doing bitcoind_txid_lookup repeatedly
* on unknown txs. */
static void insert_null_txwatch(struct lightningd_state *dstate,
const struct sha256_double *txid)
{
struct txwatch *w = tal(dstate, struct txwatch);
w->depth = 0;
w->txid = *txid;
w->dstate = dstate;
w->peer = NULL;
w->cb = NULL;
w->cbdata = NULL;
txwatch_hash_add(&w->dstate->txwatches, w);
tal_add_destructor(w, destroy_txwatch);
}
void add_anchor_watch_(const tal_t *ctx,
struct peer *peer,
const struct sha256_double *txid,
unsigned int out,
void (*anchor_cb)(struct peer *peer, int depth,
const struct sha256_double *blkhash,
void *),
void (*spend_cb)(struct peer *peer,
const struct bitcoin_tx *, void *),
void *cbdata)
{
struct sha256 h;
struct ripemd160 redeemhash;
u8 *redeemscript;
insert_txwatch(ctx, peer, txid, anchor_cb, cbdata);
insert_txo_watch(ctx, peer, txid, out, spend_cb, cbdata);
redeemscript = bitcoin_redeem_2of2(ctx, &peer->them.commitkey,
&peer->us.commitkey);
sha256(&h, redeemscript, tal_count(redeemscript));
ripemd160(&redeemhash, h.u.u8, sizeof(h));
tal_free(redeemscript);
/* Telling bitcoind to watch the redeemhash address means
* it'll tell is about the anchor itself (spend to that
* address), and any commit txs (spend from that address).*/
bitcoind_watch_addr(peer->dstate, &redeemhash);
}
struct txwatch *add_commit_tx_watch_(const tal_t *ctx,
struct peer *peer,
const struct sha256_double *txid,
void (*cb)(struct peer *peer, int depth,
const struct sha256_double *blkhash,
void *),
void *cbdata)
{
return insert_txwatch(ctx, peer, txid, cb, cbdata);
/* We are already watching the anchor txo, so we don't need to
* watch anything else. */
}
static void cb_no_arg(struct peer *peer, int depth,
const struct sha256_double *blkhash, void *vcb)
{
void (*cb)(struct peer *peer, int depth) = vcb;
cb(peer, depth);
}
void add_close_tx_watch(const tal_t *ctx,
struct peer *peer,
const struct bitcoin_tx *tx,
void (*cb)(struct peer *peer, int depth))
{
struct sha256_double txid;
bitcoin_txid(tx, &txid);
insert_txwatch(ctx, peer, &txid, cb_no_arg, cb);
/* We are already watching the anchor txo, so we don't need to
* watch anything else. */
}
static void tx_watched_inputs(struct lightningd_state *dstate,
const struct bitcoin_tx *tx, void *unused)
{
size_t in;
for (in = 0; in < tx->input_count; in++) {
struct txwatch_output out;
struct txowatch *txow;
out.txid = tx->input[in].txid;
out.index = tx->input[in].index;
txow = txowatch_hash_get(&dstate->txowatches, &out);
if (txow)
txow->cb(txow->peer, tx, txow->cbdata);
}
}
static void watched_transaction(struct lightningd_state *dstate,
const struct sha256_double *txid,
int confirmations,
bool is_coinbase,
const struct sha256_double *blkhash)
{
struct txwatch *txw;
/* Are we watching this txid directly (or already reported)? */
txw = txwatch_hash_get(&dstate->txwatches, txid);
if (txw) {
if (confirmations != txw->depth) {
txw->depth = confirmations;
if (txw->cb)
txw->cb(txw->peer, txw->depth, blkhash,
txw->cbdata);
}
return;
}
/* Don't report about this txid twice. */
insert_null_txwatch(dstate, txid);
/* Maybe it spent an output we're watching? */
if (!is_coinbase)
bitcoind_txid_lookup(dstate, txid, tx_watched_inputs, NULL);
}
static struct timeout watch_timeout;
static void start_poll_transactions(struct lightningd_state *dstate)
{
if (!list_empty(&dstate->bitcoin_req)) {
log_unusual(dstate->base_log,
"Delaying start poll: commands in progress");
} else
bitcoind_poll_transactions(dstate, watched_transaction);
refresh_timeout(dstate, &watch_timeout);
}
void setup_watch_timer(struct lightningd_state *dstate)
{
init_timeout(&watch_timeout, dstate->config.poll_seconds,
start_poll_transactions, dstate);
/* Run once immediately, in case there are issues. */
start_poll_transactions(dstate);
}