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Fixed splice_locked messgae to include splice_txid field and other interop fixes #6

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remyers wants to merge 3 commits into from
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Fixed splice_locked messgae to include splice_txid field and other interop fixes #6

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79bf18b
Splice: Rotating funding pubkey fix
ddustin Jan 21, 2025
1d98b89
Fixed splice_locked messgae to include splice_txid field
remyers Jan 22, 2025
dc3ae19
Add debug outputs and fix prevtx issue
remyers Jan 27, 2025
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19 changes: 10 additions & 9 deletions channeld/channeld.c
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Original file line number Diff line number Diff line change
Expand Up @@ -511,13 +511,14 @@ static void check_mutual_splice_locked(struct peer *peer)
}

/* Our peer told us they saw our splice confirm on chain with `splice_locked`.
* If we see it to we jump into tansitioning to post-splice, otherwise we mark
* If we see it to we jump into transitioning to post-splice, otherwise we mark
* a flag and wait until we see it on chain too. */
static void handle_peer_splice_locked(struct peer *peer, const u8 *msg)
{
struct channel_id chanid;
struct bitcoin_txid splice_txid;

if (!fromwire_splice_locked(msg, &chanid))
if (!fromwire_splice_locked(msg, &chanid, &splice_txid))
peer_failed_warn(peer->pps, &peer->channel_id,
"Bad splice_locked %s", tal_hex(msg, msg));

Expand Down Expand Up @@ -3306,7 +3307,7 @@ static void resume_splice_negotiation(struct peer *peer,
struct bitcoin_tx *bitcoin_tx;
u32 splice_funding_index;
const u8 *msg, *sigmsg;
u32 chan_output_index;
u32 new_output_index;
struct pubkey *their_pubkey;
struct bitcoin_tx *final_tx;
struct bitcoin_txid final_txid;
Expand Down Expand Up @@ -3337,8 +3338,8 @@ static void resume_splice_negotiation(struct peer *peer,
&peer->channel->funding_pubkey[LOCAL],
&peer->channel->funding_pubkey[REMOTE]);

find_channel_output(peer, current_psbt, &chan_output_index,
&peer->channel->funding_pubkey[REMOTE]);
find_channel_output(peer, current_psbt, &new_output_index,
&inflight->remote_funding);

splice_funding_index = find_channel_funding_input(current_psbt,
&peer->channel->funding);
Expand Down Expand Up @@ -3622,7 +3623,7 @@ static void resume_splice_negotiation(struct peer *peer,

final_tx = bitcoin_tx_with_psbt(tmpctx, current_psbt);
msg = towire_channeld_splice_confirmed_signed(tmpctx, final_tx,
chan_output_index);
new_output_index);
wire_sync_write(MASTER_FD, take(msg));
}
}
Expand Down Expand Up @@ -5214,7 +5215,7 @@ static void peer_reconnect(struct peer *peer,
status_info("We have no pending splice but peer"
" expects one; resending splice_lock");
peer_write(peer->pps,
take(towire_splice_locked(NULL, &peer->channel_id)));
take(towire_splice_locked(NULL, &peer->channel_id, &peer->channel->funding.txid)));

@ddustin ddustin Jan 22, 2025

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This should be &peer->splice_state->locked_txid -- however this value is not preserved after channel restarts, so that needs to addressed as well.

@ddustin ddustin Jan 22, 2025

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This is a bit of a heavy lift. I think this is the best way to make splice_state->locked_txid work over restarts.

  1. Adding {SQL("ALTER TABLE channel_funding_inflights ADD locked_onchain BOOL DEFAULT 0"), NULL}, to db.c at the end of the db table be able to mark an inflight locked onchain
  2. inflight.c needs to add serializiation of is_locked with inflight->is_locked = fromwire_bool(cursor, max); in fromwire_inflight and towire_bool(pptr, inflight->is_locked); in towire_inflight.
  3. Modifying channeld_updating_inflight to include an is_locked parameter
  4. Update handle_update_inflight to take is_locked parameter and update that value in its inflight
  5. Modify wallet_inflight_save SQL query to save is_locked to the database
  6. Modify wallet_channel_load_inflights to load `is_locked from the database
  7. Update the inflight copy code in the loop above towire_channeld_init to add is_locked to the infcopy
  8. Below fromwire_channeld_init, loop through each inflight in peer->splice_state->inflights and get the txid from the psbt of the one that is_locked, placing it in peer->splice_state->locked_txid. Additionally it would be useful to assert only 1 is locked as two would be an error.

I thiiiiink that would do it.

@remyers remyers Jan 23, 2025

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This is a bit of a heavy lift. I think this is the best way to make splice_state->locked_txid work over restarts.

I can't really comment on if that's the right approach. Do you need to use splice_state->locked_txid during reconnect? It should already be your latest funding tx once you have sent and received splice_locked. If it has reached acceptable depth then your node can resend splice_locked with the txid of the latest funding tx. You must have already have saved that information after you exchanged splice_locked with your peer.

However, when you do a reconnect before exchanging splice_locked I can see that you'll need to save the txid of the funding tx negotiated for the splice. We save this information with the splice commitment along with the signatures exchanged.

@ddustin ddustin Feb 1, 2025

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If it has reached acceptable depth then your node can resend splice_locked with the txid of the latest funding tx.

Yes you're right, peer->channel->funding.txid is correct in this case.

There needs to be a new separate case that uses peer->splice_state->locked_txid that I'm working on at the moment.

}
else {
splice_abort(peer, "next_funding_txid not recognized."
Expand Down Expand Up @@ -5593,10 +5594,10 @@ static void handle_funding_depth(struct peer *peer, const u8 *msg)
} else if(splicing && !peer->splice_state->locked_ready[LOCAL]) {
assert(scid);

msg = towire_splice_locked(NULL, &peer->channel_id);

peer->splice_state->locked_txid = txid;

msg = towire_splice_locked(NULL, &peer->channel_id, &peer->splice_state->locked_txid);

peer_write(peer->pps, take(msg));

peer->splice_state->locked_ready[LOCAL] = true;
Expand Down
1 change: 1 addition & 0 deletions wire/peer_wire.csv
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Original file line number Diff line number Diff line change
Expand Up @@ -223,6 +223,7 @@ msgdata,splice_ack,relative_satoshis,s64,
msgdata,splice_ack,funding_pubkey,point,
msgtype,splice_locked,77,
msgdata,splice_locked,channel_id,channel_id,
msgdata,splice_locked,splice_txid,sha256,
msgtype,shutdown,38
msgdata,shutdown,channel_id,channel_id,
msgdata,shutdown,len,u16,
Expand Down