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lightningd: clean up HTLC error handling. 

Some paths were still sending unencrypted failure messages; unify them
all.  We need to keep the fail_msg around for resubmission if the
channeld dies; similarly, we need to keep the htlc_end structure
itself after failure, in case the failed HTLC is committed: we can
move it to a minimal archive once it's flushed from both sides,
however.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
ppa-0.6.1
Rusty Russell 7 years ago
parent
7105085801
commit
6e28412f8f
2 changed files with 61 additions and 90 deletions
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  1. 3
      lightningd/htlc_end.h
  2. 148
      lightningd/peer_control.c

3
lightningd/htlc_end.h
View File

@ -29,6 +29,9 @@ struct htlc_end {
u32 cltv_expiry;
struct sha256 payment_hash;
/* If we failed HTLC, here's the message. */
const u8 *fail_msg;
/* If we are forwarding, remember the shared secret for an
* eventual reply */
struct secret *shared_secret;

148
lightningd/peer_control.c
View File

@ -791,39 +791,24 @@ struct decoding_htlc {
struct secret shared_secret;
};
static void fail_htlc(struct peer *peer, struct htlc_end *hend, const u8 *msg)
{
u8 *reply = wrap_onionreply(hend, hend->shared_secret, msg);
subd_send_msg(peer->owner,
take(towire_channel_fail_htlc(peer, hend->htlc_id, reply)));
if (taken(msg))
tal_free(msg);
}
static void fail_local_htlc(struct peer *peer, struct htlc_end *hend, const u8 *msg)
/* This obfuscates the message, whether local or forwarded. */
static void relay_htlc_failmsg(struct htlc_end *hend)
{
u8 *reply;
enum onion_type failcode = fromwire_peektype(msg);
log_broken(peer->log, "failed htlc %"PRIu64" code 0x%04x (%s)",
hend->htlc_id, failcode, onion_type_name(failcode));
reply = create_onionreply(hend, hend->shared_secret, msg);
fail_htlc(peer, hend, reply);
if (!hend->peer->owner)
return;
reply = wrap_onionreply(hend, hend->shared_secret, hend->fail_msg);
subd_send_msg(hend->peer->owner,
take(towire_channel_fail_htlc(hend, hend->htlc_id, reply)));
tal_free(reply);
}
static u8 *make_failmsg(const tal_t *ctx, const struct htlc_end *hend,
enum onion_type failcode)
enum onion_type failcode,
const struct sha256 *onion_sha, const u8 *channel_update)
{
struct sha256 *onion_sha = NULL;
u8 *channel_update = NULL;
if (failcode & BADONION) {
/* FIXME: need htlc_end->sha? */
}
if (failcode & UPDATE) {
/* FIXME: Ask gossip daemon for channel_update. */
}
switch (failcode) {
case WIRE_INVALID_REALM:
return towire_invalid_realm(ctx);
@ -873,6 +858,26 @@ static u8 *make_failmsg(const tal_t *ctx, const struct htlc_end *hend,
abort();
}
static void fail_htlc(struct htlc_end *hend, enum onion_type failcode,
const struct sha256 *onion_sha)
{
u8 *msg;
log_broken(hend->peer->log, "failed htlc %"PRIu64" code 0x%04x (%s)",
hend->htlc_id, failcode, onion_type_name(failcode));
if (failcode & UPDATE) {
/* FIXME: Ask gossip daemon for channel_update. */
}
msg = make_failmsg(hend, hend, failcode, onion_sha, NULL);
hend->fail_msg = create_onionreply(hend, hend->shared_secret, msg);
tal_free(msg);
relay_htlc_failmsg(hend);
}
/* BOLT #4:
*
* * `amt_to_forward` - The amount in milli-satoshi to forward to the next
@ -950,7 +955,7 @@ static void handle_localpay(struct htlc_end *hend,
u64 amt_to_forward,
u32 outgoing_cltv_value)
{
u8 *err;
enum onion_type failcode;
struct invoice *invoice;
/* BOLT #4:
@ -963,7 +968,7 @@ static void handle_localpay(struct htlc_end *hend,
* * [`4`:`incoming_htlc_amt`]
*/
if (!check_amount(hend, amt_to_forward, hend->msatoshis, 0)) {
err = towire_final_incorrect_htlc_amount(hend, hend->msatoshis);
failcode = WIRE_FINAL_INCORRECT_HTLC_AMOUNT;
goto fail;
}
@ -977,13 +982,13 @@ static void handle_localpay(struct htlc_end *hend,
* * [`4`:`cltv_expiry`]
*/
if (!check_ctlv(hend, cltv_expiry, outgoing_cltv_value, 0)) {
err = towire_final_incorrect_cltv_expiry(hend, cltv_expiry);
failcode = WIRE_FINAL_INCORRECT_CLTV_EXPIRY;
goto fail;
}
invoice = find_unpaid(hend->peer->ld->dstate.invoices, payment_hash);
if (!invoice) {
err = towire_unknown_payment_hash(hend);
failcode = WIRE_UNKNOWN_PAYMENT_HASH;
goto fail;
}
@ -998,10 +1003,10 @@ static void handle_localpay(struct htlc_end *hend,
* 1. type: PERM|16 (`incorrect_payment_amount`)
*/
if (hend->msatoshis < invoice->msatoshi) {
err = towire_incorrect_payment_amount(hend);
failcode = WIRE_INCORRECT_PAYMENT_AMOUNT;
goto fail;
} else if (hend->msatoshis > invoice->msatoshi * 2) {
err = towire_incorrect_payment_amount(hend);
failcode = WIRE_INCORRECT_PAYMENT_AMOUNT;
goto fail;
}
@ -1016,7 +1021,7 @@ static void handle_localpay(struct htlc_end *hend,
cltv_expiry,
get_block_height(hend->peer->ld->topology),
hend->peer->ld->dstate.config.deadline_blocks);
err = towire_final_expiry_too_soon(hend);
failcode = WIRE_FINAL_EXPIRY_TOO_SOON;
goto fail;
}
@ -1029,8 +1034,7 @@ static void handle_localpay(struct htlc_end *hend,
return;
fail:
fail_local_htlc(hend->peer, hend, take(err));
tal_free(hend);
fail_htlc(hend, failcode, NULL);
}
/*
@ -1040,18 +1044,11 @@ fail:
*/
static void hend_subd_died(struct htlc_end *hend)
{
/* FIXME: Ask gossip daemon for channel_update. */
u8 *channel_update = NULL;
u8 *failmsg = towire_temporary_channel_failure(hend->other_end,
channel_update);
u8 *msg = towire_channel_fail_htlc(hend->other_end,
hend->other_end->htlc_id,
failmsg);
log_debug(hend->other_end->peer->owner->log,
"Failing HTLC %"PRIu64" due to peer death",
hend->other_end->htlc_id);
subd_send_msg(hend->other_end->peer->owner, take(msg));
tal_free(failmsg);
fail_htlc(hend->other_end, WIRE_TEMPORARY_CHANNEL_FAILURE, NULL);
}
static bool rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds,
@ -1075,9 +1072,7 @@ static bool rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds,
onion_type_name(failure_code),
(int)tal_len(failurestr), (char *)failurestr);
msg = make_failmsg(msg, hend->other_end, failure_code);
subd_send_msg(hend->other_end->peer->owner, take(msg));
tal_free(hend);
fail_htlc(hend->other_end, failure_code, NULL);
return true;
}
@ -1096,19 +1091,20 @@ static void forward_htlc(struct htlc_end *hend,
const struct pubkey *next_hop,
const u8 next_onion[TOTAL_PACKET_SIZE])
{
u8 *err, *msg;
u8 *msg;
enum onion_type failcode;
u64 fee;
struct lightningd *ld = hend->peer->ld;
struct peer *next = peer_by_id(ld, next_hop);
if (!next) {
err = towire_unknown_next_peer(hend);
failcode = WIRE_UNKNOWN_NEXT_PEER;
goto fail;
}
if (!peer_can_add_htlc(next)) {
log_info(next->log, "Attempt to forward HTLC but not ready");
err = towire_unknown_next_peer(hend);
failcode = WIRE_UNKNOWN_NEXT_PEER;
goto fail;
}
@ -1121,22 +1117,19 @@ static void forward_htlc(struct htlc_end *hend,
*/
if (mul_overflows_u64(amt_to_forward,
ld->dstate.config.fee_per_satoshi)) {
/* FIXME: Add channel update */
err = towire_fee_insufficient(hend, hend->msatoshis, NULL);
failcode = WIRE_FEE_INSUFFICIENT;
goto fail;
}
fee = ld->dstate.config.fee_base
+ amt_to_forward * ld->dstate.config.fee_per_satoshi / 1000000;
if (!check_amount(hend, amt_to_forward, hend->msatoshis, fee)) {
/* FIXME: Add channel update */
err = towire_fee_insufficient(hend, hend->msatoshis, NULL);
failcode = WIRE_FEE_INSUFFICIENT;
goto fail;
}
if (!check_ctlv(hend, cltv_expiry, outgoing_cltv_value,
ld->dstate.config.deadline_blocks)) {
/* FIXME: Add channel update */
err = towire_incorrect_cltv_expiry(hend, cltv_expiry, NULL);
failcode = WIRE_INCORRECT_CLTV_EXPIRY;
goto fail;
}
@ -1156,8 +1149,7 @@ static void forward_htlc(struct htlc_end *hend,
outgoing_cltv_value,
get_block_height(next->ld->topology),
next->ld->dstate.config.deadline_blocks);
/* FIXME: Add channel update */
err = towire_expiry_too_soon(hend, NULL);
failcode = WIRE_EXPIRY_TOO_SOON;
goto fail;
}
@ -1178,8 +1170,7 @@ static void forward_htlc(struct htlc_end *hend,
return;
fail:
fail_local_htlc(hend->peer, hend, take(err));
tal_free(hend);
fail_htlc(hend, failcode, NULL);
}
/* We received a resolver reply, which gives us the node_ids of the
@ -1197,9 +1188,7 @@ static bool channel_resolve_reply(struct subd *gossip, const u8 *msg,
}
if (tal_count(nodes) == 0) {
fail_htlc(hend->peer, hend,
take(towire_unknown_next_peer(hend)));
tal_free(hend);
fail_htlc(hend, WIRE_UNKNOWN_NEXT_PEER, NULL);
return true;
} else if (tal_count(nodes) != 2) {
log_broken(gossip->log,
@ -1248,6 +1237,7 @@ static int peer_accepted_htlc(struct peer *peer, const u8 *msg)
hend->peer = peer;
hend->other_end = NULL;
hend->pay_command = NULL;
hend->fail_msg = NULL;
if (forward) {
req = towire_gossip_resolve_channel_request(msg, &hend->next_channel);
@ -1316,8 +1306,8 @@ static int peer_failed_htlc(struct peer *peer, const u8 *msg)
}
if (hend->other_end) {
fail_htlc(hend->other_end->peer, hend->other_end,
reason);
hend->other_end->fail_msg = tal_steal(hend->other_end, reason);
relay_htlc_failmsg(hend->other_end);
} else {
size_t numhops = tal_count(hend->path_secrets);
struct secret *shared_secrets = tal_arr(hend, struct secret, numhops);
@ -1334,34 +1324,13 @@ static int peer_failed_htlc(struct peer *peer, const u8 *msg)
log_info(peer->log, "htlc %"PRIu64" failed with code 0x%04x (%s)",
id, failcode, onion_type_name(failcode));
}
/* FIXME: Apply update if it contains it, etc */
payment_failed(peer->ld, hend, NULL, failcode);
}
tal_free(hend);
return 0;
}
/* FIXME: Encrypt! */
static u8 *malformed_msg(const tal_t *ctx, enum onion_type type,
const struct sha256 *sha256_of_onion)
{
u8 *channel_update;
/* FIXME: check the reported SHA matches what we sent! */
switch (type) {
case WIRE_INVALID_ONION_VERSION:
return towire_invalid_onion_version(ctx, sha256_of_onion);
case WIRE_INVALID_ONION_HMAC:
return towire_invalid_onion_hmac(ctx, sha256_of_onion);
case WIRE_INVALID_ONION_KEY:
return towire_invalid_onion_key(ctx, sha256_of_onion);
default:
/* FIXME: Ask gossip daemon for channel_update. */
channel_update = NULL;
return towire_temporary_channel_failure(ctx, channel_update);
}
}
static int peer_failed_malformed_htlc(struct peer *peer, const u8 *msg)
{
u64 id;
@ -1388,12 +1357,11 @@ static int peer_failed_malformed_htlc(struct peer *peer, const u8 *msg)
/* Not really a local failure, but since the failing
* peer could not derive its shared secret it cannot
* create a valid HMAC, so we do it on his behalf */
fail_local_htlc(hend->other_end->peer, hend->other_end,
malformed_msg(msg, failcode, &sha256_of_onion));
fail_htlc(hend->other_end, failcode, &sha256_of_onion);
} else {
payment_failed(peer->ld, hend, NULL, failcode);
}
tal_free(hend);
return 0;
}

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