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peer_htlcs.c
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#include "config.h"
#include <ccan/cast/cast.h>
#include <ccan/tal/str/str.h>
#include <channeld/channeld_wiregen.h>
#include <common/blinding.h>
#include <common/configdir.h>
#include <common/ecdh.h>
#include <common/json_command.h>
#include <common/json_param.h>
#include <common/onion.h>
#include <common/onionreply.h>
#include <common/timeout.h>
#include <common/type_to_string.h>
#include <db/exec.h>
#include <gossipd/gossipd_wiregen.h>
#include <lightningd/chaintopology.h>
#include <lightningd/channel.h>
#include <lightningd/coin_mvts.h>
#include <lightningd/pay.h>
#include <lightningd/peer_control.h>
#include <lightningd/peer_htlcs.h>
#include <lightningd/plugin_hook.h>
#include <lightningd/subd.h>
#include <onchaind/onchaind_wiregen.h>
#ifndef SUPERVERBOSE
#define SUPERVERBOSE(...)
#endif
static bool state_update_ok(struct channel *channel,
enum htlc_state oldstate, enum htlc_state newstate,
u64 htlc_id, const char *dir)
{
enum htlc_state expected = oldstate + 1;
/* We never get told about RCVD_REMOVE_HTLC, so skip over that
* (we initialize in SENT_ADD_HTLC / RCVD_ADD_COMMIT, so those
* work). */
if (expected == RCVD_REMOVE_HTLC)
expected = RCVD_REMOVE_COMMIT;
if (newstate != expected) {
channel_internal_error(channel,
"HTLC %s %"PRIu64" invalid update %s->%s",
dir, htlc_id,
htlc_state_name(oldstate),
htlc_state_name(newstate));
return false;
}
log_debug(channel->log, "HTLC %s %"PRIu64" %s->%s",
dir, htlc_id,
htlc_state_name(oldstate), htlc_state_name(newstate));
return true;
}
static bool htlc_in_update_state(struct channel *channel,
struct htlc_in *hin,
enum htlc_state newstate)
{
if (!state_update_ok(channel, hin->hstate, newstate, hin->key.id, "in"))
return false;
wallet_htlc_update(channel->peer->ld->wallet,
hin->dbid, newstate, hin->preimage,
max_unsigned(channel->next_index[LOCAL],
channel->next_index[REMOTE]),
hin->badonion, hin->failonion, NULL,
hin->we_filled);
hin->hstate = newstate;
return true;
}
static bool htlc_out_update_state(struct channel *channel,
struct htlc_out *hout,
enum htlc_state newstate)
{
if (!state_update_ok(channel, hout->hstate, newstate, hout->key.id,
"out"))
return false;
bool we_filled = false;
wallet_htlc_update(channel->peer->ld->wallet, hout->dbid, newstate,
hout->preimage,
max_unsigned(channel->next_index[LOCAL],
channel->next_index[REMOTE]),
0, hout->failonion,
hout->failmsg, &we_filled);
hout->hstate = newstate;
return true;
}
static struct failed_htlc *mk_failed_htlc_badonion(const tal_t *ctx,
const struct htlc_in *hin,
enum onion_wire badonion)
{
struct failed_htlc *f = tal(ctx, struct failed_htlc);
f->id = hin->key.id;
f->onion = NULL;
f->badonion = badonion;
f->sha256_of_onion = tal(f, struct sha256);
sha256(f->sha256_of_onion, hin->onion_routing_packet,
sizeof(hin->onion_routing_packet));
return f;
}
static struct failed_htlc *mk_failed_htlc(const tal_t *ctx,
const struct htlc_in *hin,
const struct onionreply *failonion)
{
struct failed_htlc *f = tal(ctx, struct failed_htlc);
f->id = hin->key.id;
f->sha256_of_onion = NULL;
f->badonion = 0;
/* Wrap onion error */
f->onion = wrap_onionreply(f, hin->shared_secret, failonion);
return f;
}
static void tell_channeld_htlc_failed(const struct htlc_in *hin,
const struct failed_htlc *failed_htlc)
{
/* Tell peer, if we can. */
if (!hin->key.channel->owner)
return;
/* onchaind doesn't care, it can't do anything but wait */
if (!channel_active(hin->key.channel))
return;
subd_send_msg(hin->key.channel->owner,
take(towire_channeld_fail_htlc(NULL, failed_htlc)));
}
static void fail_in_htlc(struct htlc_in *hin,
const struct onionreply *failonion TAKES)
{
struct failed_htlc *failed_htlc;
assert(!hin->preimage);
hin->failonion = dup_onionreply(hin, failonion);
/* We update state now to signal it's in progress, for persistence. */
htlc_in_update_state(hin->key.channel, hin, SENT_REMOVE_HTLC);
htlc_in_check(hin, __func__);
/* BOLT-route-blinding #4:
* - If `blinding_point` is set in the incoming `update_add_htlc`:
* - MUST return `invalid_onion_blinding` on any error, including
* downstream errors received from forwarding HTLCs.
*/
if (hin->blinding) {
failed_htlc = mk_failed_htlc_badonion(tmpctx, hin,
WIRE_INVALID_ONION_BLINDING);
} else
failed_htlc = mk_failed_htlc(tmpctx, hin, hin->failonion);
bool we_filled = false;
wallet_htlc_update(hin->key.channel->peer->ld->wallet,
hin->dbid, hin->hstate,
hin->preimage,
max_unsigned(hin->key.channel->next_index[LOCAL],
hin->key.channel->next_index[REMOTE]),
hin->badonion,
hin->failonion, NULL, &we_filled);
tell_channeld_htlc_failed(hin, failed_htlc);
}
/* Immediately fail HTLC with a BADONION code */
static void local_fail_in_htlc_badonion(struct htlc_in *hin,
enum onion_wire badonion)
{
struct failed_htlc *failed_htlc;
assert(!hin->preimage);
assert(badonion & BADONION);
hin->badonion = badonion;
/* We update state now to signal it's in progress, for persistence. */
htlc_in_update_state(hin->key.channel, hin, SENT_REMOVE_HTLC);
htlc_in_check(hin, __func__);
failed_htlc = mk_failed_htlc_badonion(tmpctx, hin, badonion);
tell_channeld_htlc_failed(hin, failed_htlc);
}
/* This is used for cases where we can immediately fail the HTLC. */
void local_fail_in_htlc(struct htlc_in *hin, const u8 *failmsg TAKES)
{
struct onionreply *failonion = create_onionreply(NULL,
hin->shared_secret,
failmsg);
if (taken(failmsg))
tal_free(failmsg);
fail_in_htlc(hin, take(failonion));
}
/* Helper to create (common) WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS */
const u8 *failmsg_incorrect_or_unknown_(const tal_t *ctx,
struct lightningd *ld,
const struct htlc_in *hin,
const char *file, int line)
{
log_debug(ld->log, "WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS: %s:%u",
file, line);
return towire_incorrect_or_unknown_payment_details(
ctx, hin->msat,
get_block_height(ld->topology));
}
/* localfail are for handing to the local payer if it's local. */
static void fail_out_htlc(struct htlc_out *hout, const char *localfail)
{
htlc_out_check(hout, __func__);
assert(hout->failmsg || hout->failonion);
if (hout->am_origin) {
payment_failed(hout->key.channel->peer->ld, hout, localfail);
} else if (hout->in) {
const struct onionreply *failonion;
/* If we have an onion, simply copy it. */
if (hout->failonion)
failonion = hout->failonion;
/* Otherwise, we need to onionize this local error. */
else
failonion = create_onionreply(hout,
hout->in->shared_secret,
hout->failmsg);
fail_in_htlc(hout->in, failonion);
} else {
log_broken(hout->key.channel->log, "Neither origin nor in?");
}
}
/* BOLT #4:
*
* * `amt_to_forward`: The amount, in millisatoshis, to forward to the next
* receiving peer specified within the routing information.
*
* For non-final nodes, this value amount MUST include the origin node's computed _fee_ for the
* receiving peer. When processing an incoming Sphinx packet and the HTLC
* message that it is encapsulated within, if the following inequality
* doesn't hold, then the HTLC should be rejected as it would indicate that
* a prior hop has deviated from the specified parameters:
*
* incoming_htlc_amt - fee >= amt_to_forward
*
* Where `fee` is calculated according to the receiving peer's
* advertised fee schema (as described in [BOLT
* #7](07-routing-gossip.md#htlc-fees)).
*/
static bool check_fwd_amount(struct htlc_in *hin,
struct amount_msat amt_to_forward,
struct amount_msat amt_in_htlc,
u32 feerate_base, u32 feerate_ppm)
{
struct amount_msat fee;
struct amount_msat fwd;
if (!amount_msat_fee(&fee, amt_to_forward,
feerate_base, feerate_ppm)) {
log_broken(hin->key.channel->log, "Fee overflow forwarding %s!",
type_to_string(tmpctx, struct amount_msat,
&amt_to_forward));
return false;
}
if (amount_msat_sub(&fwd, amt_in_htlc, fee)
&& amount_msat_greater_eq(fwd, amt_to_forward))
return true;
log_debug(hin->key.channel->log, "HTLC %"PRIu64" incorrect amount:"
" %s in, %s out, fee reqd %s",
hin->key.id,
type_to_string(tmpctx, struct amount_msat, &amt_in_htlc),
type_to_string(tmpctx, struct amount_msat, &amt_to_forward),
type_to_string(tmpctx, struct amount_msat, &fee));
return false;
}
/* BOLT #4:
*
* * `outgoing_cltv_value`: The CLTV value that the _outgoing_ HTLC carrying
* the packet should have.
*
* cltv_expiry - cltv_expiry_delta >= outgoing_cltv_value
*
* Inclusion of this field allows a hop to both authenticate the
* information specified by the origin node, and the parameters of the
* HTLC forwarded, and ensure the origin node is using the current
* `cltv_expiry_delta` value. If there is no next hop,
* `cltv_expiry_delta` is 0. If the values don't correspond, then the
* HTLC should be failed and rejected, as this indicates that either a
* forwarding node has tampered with the intended HTLC values or that the
* origin node has an obsolete `cltv_expiry_delta` value. The hop MUST be
* consistent in responding to an unexpected `outgoing_cltv_value`,
* whether it is the final node or not, to avoid leaking its position in
* the route.
*/
static bool check_cltv(struct htlc_in *hin,
u32 cltv_expiry, u32 outgoing_cltv_value, u32 delta)
{
if (delta < cltv_expiry && cltv_expiry - delta >= outgoing_cltv_value)
return true;
log_debug(hin->key.channel->log, "HTLC %"PRIu64" incorrect CLTV:"
" %u in, %u out, delta reqd %u",
hin->key.id, cltv_expiry, outgoing_cltv_value, delta);
return false;
}
void fulfill_htlc(struct htlc_in *hin, const struct preimage *preimage)
{
u8 *msg;
struct channel *channel = hin->key.channel;
struct wallet *wallet = channel->peer->ld->wallet;
if (hin->hstate != RCVD_ADD_ACK_REVOCATION) {
log_debug(channel->log,
"HTLC fulfilled, but not ready any more (%s).",
htlc_state_name(hin->hstate));
return;
}
hin->preimage = tal_dup(hin, struct preimage, preimage);
/* We update state now to signal it's in progress, for persistence. */
htlc_in_update_state(channel, hin, SENT_REMOVE_HTLC);
htlc_in_check(hin, __func__);
/* Update channel stats */
wallet_channel_stats_incr_in_fulfilled(wallet,
channel->dbid,
hin->msat);
/* No owner? We'll either send to channeld in peer_htlcs, or
* onchaind in onchaind_tell_fulfill. */
if (!channel->owner) {
log_debug(channel->log, "HTLC fulfilled, but no owner.");
return;
}
if (channel_on_chain(channel)) {
msg = towire_onchaind_known_preimage(hin, preimage);
} else {
struct fulfilled_htlc fulfilled_htlc;
fulfilled_htlc.id = hin->key.id;
fulfilled_htlc.payment_preimage = *preimage;
msg = towire_channeld_fulfill_htlc(hin, &fulfilled_htlc);
}
subd_send_msg(channel->owner, take(msg));
}
static void handle_localpay(struct htlc_in *hin,
struct amount_msat amt_to_forward,
u32 outgoing_cltv_value,
struct amount_msat total_msat,
const struct secret *payment_secret,
const u8 *payment_metadata)
{
const u8 *failmsg;
struct lightningd *ld = hin->key.channel->peer->ld;
/* BOLT #4:
*
* For the final node, this value MUST be exactly equal to the
* incoming htlc amount, otherwise the HTLC should be rejected.
*/
if (!amount_msat_eq(amt_to_forward, hin->msat)) {
log_debug(hin->key.channel->log,
"HTLC %"PRIu64" final incorrect amount:"
" %s in, %s expected",
hin->key.id,
type_to_string(tmpctx, struct amount_msat, &hin->msat),
type_to_string(tmpctx, struct amount_msat,
&amt_to_forward));
/* BOLT #4:
*
* 1. type: 19 (`final_incorrect_htlc_amount`)
* 2. data:
* * [`u64`:`incoming_htlc_amt`]
*
* The amount in the HTLC doesn't match the value in the onion.
*/
failmsg = towire_final_incorrect_htlc_amount(NULL, hin->msat);
goto fail;
}
/* BOLT #4:
*
* 1. type: 18 (`final_incorrect_cltv_expiry`)
* 2. data:
* * [`u32`:`cltv_expiry`]
*
* The CLTV expiry in the HTLC doesn't match the value in the onion.
*/
if (!check_cltv(hin, hin->cltv_expiry, outgoing_cltv_value, 0)) {
failmsg = towire_final_incorrect_cltv_expiry(NULL,
hin->cltv_expiry);
goto fail;
}
/* BOLT #4:
*
* - if the `cltv_expiry` value is unreasonably near the present:
* - MUST fail the HTLC.
* - MUST return an `incorrect_or_unknown_payment_details` error.
*/
if (get_block_height(ld->topology) + ld->config.cltv_final
> hin->cltv_expiry) {
log_debug(hin->key.channel->log,
"Expiry cltv too soon %u < %u + %u",
hin->cltv_expiry,
get_block_height(ld->topology),
ld->config.cltv_final);
failmsg = failmsg_incorrect_or_unknown(NULL, ld, hin);
goto fail;
}
/* We don't expect payment_metadata; reject here */
if (payment_metadata) {
log_debug(hin->key.channel->log,
"Unexpected payment_metadata %s",
tal_hex(tmpctx, payment_metadata));
/* BOLT #4:
* 1. type: PERM|22 (`invalid_onion_payload`)
* 2. data:
* * [`bigsize`:`type`]
* * [`u16`:`offset`]
*
* The decrypted onion per-hop payload was not understood by the processing node
* or is incomplete. If the failure can be narrowed down to a specific tlv type in
* the payload, the erring node may include that `type` and its byte `offset` in
* the decrypted byte stream.
*/
failmsg = towire_invalid_onion_payload(NULL, TLV_TLV_PAYLOAD_PAYMENT_METADATA,
/* FIXME: offset? */ 0);
goto fail;
}
htlc_set_add(ld, hin, total_msat, payment_secret);
return;
fail:
local_fail_in_htlc(hin, take(failmsg));
}
/*
* A catchall in case outgoing peer disconnects before getting fwd.
*
* We could queue this and wait for it to come back, but this is simple.
*/
static void destroy_hout_subd_died(struct htlc_out *hout)
{
struct db *db = hout->key.channel->peer->ld->wallet->db;
/* Under some circumstances we may need to start a DB
* transaction and commit it here again. This is the case when
* we're getting called from the destructor chain. */
bool have_tx =
db_in_transaction(db);
log_debug(hout->key.channel->log,
"Failing HTLC %"PRIu64" due to peer death",
hout->key.id);
hout->failmsg = towire_temporary_channel_failure(hout,
get_channel_update(hout->key.channel));
/* Assign a temporary state (we're about to free it!) so checks
* are happy that it has a failure message */
assert(hout->hstate == SENT_ADD_HTLC);
hout->hstate = RCVD_REMOVE_HTLC;
if (!have_tx)
db_begin_transaction(db);
fail_out_htlc(hout, "Outgoing subdaemon died");
if (!have_tx)
db_commit_transaction(db);
}
/* This is where channeld gives us the HTLC id, and also reports if it
* failed immediately. */
static void rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds UNUSED,
struct htlc_out *hout)
{
u8 *failmsg;
char *failurestr;
struct lightningd *ld = subd->ld;
if (!fromwire_channeld_offer_htlc_reply(msg, msg,
&hout->key.id,
&failmsg,
&failurestr)) {
channel_internal_error(subd->channel,
"Bad channel_offer_htlc_reply");
tal_free(hout);
return;
}
if (tal_count(failmsg)) {
hout->failmsg = tal_steal(hout, failmsg);
if (hout->am_origin) {
char *localfail = tal_fmt(msg, "%s: %s",
onion_wire_name(fromwire_peektype(failmsg)),
failurestr);
payment_failed(ld, hout, localfail);
} else if (hout->in) {
struct onionreply *failonion;
failonion = create_onionreply(hout,
hout->in->shared_secret,
hout->failmsg);
fail_in_htlc(hout->in, failonion);
/* here we haven't called connect_htlc_out(),
* so set htlc field with NULL (db wants it to exist!) */
wallet_forwarded_payment_add(ld->wallet,
hout->in,
FORWARD_STYLE_TLV,
channel_scid_or_local_alias(hout->key.channel), NULL,
FORWARD_LOCAL_FAILED,
fromwire_peektype(hout->failmsg));
}
/* Prevent hout from being failed twice. */
tal_del_destructor(hout, destroy_hout_subd_died);
tal_free(hout);
return;
}
if (find_htlc_out(&subd->ld->htlcs_out, hout->key.channel, hout->key.id)
|| hout->key.id == HTLC_INVALID_ID) {
channel_internal_error(subd->channel,
"Bad offer_htlc_reply HTLC id %"PRIu64
" is a duplicate",
hout->key.id);
tal_free(hout);
return;
}
/* Add it to lookup table now we know id. */
connect_htlc_out(&subd->ld->htlcs_out, hout);
/* When channeld includes it in commitment, we'll make it persistent. */
}
static void htlc_offer_timeout(struct htlc_out *out)
{
struct channel *channel = out->key.channel;
out->timeout = NULL;
/* Otherwise, timer would be removed. */
assert(out->hstate == SENT_ADD_HTLC);
/* If owner died, we should already be taken care of. */
if (!channel->owner || channel->state != CHANNELD_NORMAL)
return;
log_unusual(channel->owner->log,
"Adding HTLC %"PRIu64" too slow: killing connection",
out->key.id);
tal_free(channel->owner);
channel_set_billboard(channel, false,
"Adding HTLC timed out: killed connection");
}
/* Returns failmsg, or NULL on success. */
const u8 *send_htlc_out(const tal_t *ctx,
struct channel *out,
struct amount_msat amount, u32 cltv,
struct amount_msat final_msat,
const struct sha256 *payment_hash,
const struct pubkey *blinding,
u64 partid,
u64 groupid,
const u8 *onion_routing_packet,
struct htlc_in *in,
struct htlc_out **houtp)
{
u8 *msg;
*houtp = NULL;
if (!channel_can_add_htlc(out)) {
log_info(out->log, "Attempt to send HTLC but not ready (%s)",
channel_state_name(out));
return towire_unknown_next_peer(ctx);
}
if (!out->owner) {
log_info(out->log, "Attempt to send HTLC but unowned (%s)",
channel_state_name(out));
return towire_temporary_channel_failure(ctx,
get_channel_update(out));
}
if (!topology_synced(out->peer->ld->topology)) {
log_info(out->log, "Attempt to send HTLC but still syncing"
" with bitcoin network");
return towire_temporary_node_failure(ctx);
}
/* Make peer's daemon own it, catch if it dies. */
*houtp = new_htlc_out(out->owner, out, amount, cltv,
payment_hash, onion_routing_packet,
blinding, in == NULL,
final_msat,
partid, groupid, in);
tal_add_destructor(*houtp, destroy_hout_subd_died);
/* Give channel 30 seconds to commit this htlc. */
if (!IFDEV(out->peer->ld->dev_no_htlc_timeout, 0)) {
(*houtp)->timeout = new_reltimer(out->peer->ld->timers,
*houtp, time_from_sec(30),
htlc_offer_timeout,
*houtp);
}
msg = towire_channeld_offer_htlc(out, amount, cltv, payment_hash,
onion_routing_packet, blinding);
subd_req(out->peer->ld, out->owner, take(msg), -1, 0, rcvd_htlc_reply,
*houtp);
return NULL;
}
/* What's the best channel to this peer?
* If @hint is set, channel must match that one. */
static struct channel *best_channel(struct lightningd *ld,
const struct peer *next_peer,
struct amount_msat amt_to_forward,
struct channel *hint)
{
struct amount_msat best_spendable = AMOUNT_MSAT(0);
struct channel *channel, *best = hint;
/* Seek channel with largest spendable! */
list_for_each(&next_peer->channels, channel, list) {
struct amount_msat spendable;
if (!channel_can_add_htlc(channel))
continue;
spendable = channel_amount_spendable(channel);
if (!amount_msat_greater(spendable, best_spendable))
continue;
/* Don't override if fees differ... */
if (hint) {
if (hint->feerate_base != channel->feerate_base
|| hint->feerate_ppm != channel->feerate_ppm)
continue;
}
/* Or if this would be below min for channel! */
if (amount_msat_less(amt_to_forward,
channel->channel_info.their_config.htlc_minimum))
continue;
best = channel;
best_spendable = spendable;
}
return best;
}
/* forward_to is where we're actually sending it (or NULL), and
* forward_scid is where they asked to send it (or NULL). */
static void forward_htlc(struct htlc_in *hin,
u32 cltv_expiry,
struct amount_msat amt_to_forward,
u32 outgoing_cltv_value,
const struct short_channel_id *forward_scid,
const struct channel_id *forward_to,
const u8 next_onion[TOTAL_PACKET_SIZE(ROUTING_INFO_SIZE)],
const struct pubkey *next_blinding)
{
const u8 *failmsg;
struct lightningd *ld = hin->key.channel->peer->ld;
struct channel *next;
struct htlc_out *hout = NULL;
if (forward_to) {
next = channel_by_cid(ld, forward_to);
/* Update this to where we're actually trying to send. */
if (next)
forward_scid = channel_scid_or_local_alias(next);
}else
next = NULL;
/* Unknown peer, or peer not ready. */
if (!next || !channel_active(next)) {
local_fail_in_htlc(hin, take(towire_unknown_next_peer(NULL)));
wallet_forwarded_payment_add(hin->key.channel->peer->ld->wallet,
hin, FORWARD_STYLE_TLV,
forward_scid, NULL,
FORWARD_LOCAL_FAILED,
WIRE_UNKNOWN_NEXT_PEER);
return;
}
/* BOLT #7:
*
* The origin node:
* - SHOULD accept HTLCs that pay a fee equal to or greater than:
* - fee_base_msat + ( amount_to_forward * fee_proportional_millionths / 1000000 )
*/
if (!check_fwd_amount(hin, amt_to_forward, hin->msat,
next->feerate_base,
next->feerate_ppm)) {
/* BOLT #7:
* - If it creates a new `channel_update` with updated channel parameters:
* - SHOULD keep accepting the previous channel parameters for 10 minutes
*/
if (!time_before(time_now(), next->old_feerate_timeout)
|| !check_fwd_amount(hin, amt_to_forward, hin->msat,
next->old_feerate_base,
next->old_feerate_ppm)) {
failmsg = towire_fee_insufficient(tmpctx, hin->msat,
get_channel_update(next));
goto fail;
}
log_info(hin->key.channel->log,
"Allowing payment using older feerate");
}
if (amount_msat_greater(amt_to_forward, next->htlc_maximum_msat)
|| amount_msat_less(amt_to_forward, next->htlc_minimum_msat)) {
/* Are we in old-range grace-period? */
if (!time_before(time_now(), next->old_feerate_timeout)
|| amount_msat_less(amt_to_forward, next->old_htlc_minimum_msat)
|| amount_msat_greater(amt_to_forward, next->old_htlc_maximum_msat)) {
failmsg = towire_temporary_channel_failure(tmpctx,
get_channel_update(next));
goto fail;
}
log_info(hin->key.channel->log,
"Allowing htlc using older htlc_minimum/maximum_msat");
}
if (!check_cltv(hin, cltv_expiry, outgoing_cltv_value,
ld->config.cltv_expiry_delta)) {
failmsg = towire_incorrect_cltv_expiry(tmpctx, cltv_expiry,
get_channel_update(next));
goto fail;
}
/* BOLT #2:
*
* An offering node:
* - MUST estimate a timeout deadline for each HTLC it offers.
* - MUST NOT offer an HTLC with a timeout deadline before its
* `cltv_expiry`.
*/
/* In our case, G = 1, so we need to expire it one after it's expiration.
* But never offer an expired HTLC; that's dumb. */
if (get_block_height(ld->topology) >= outgoing_cltv_value) {
log_debug(hin->key.channel->log,
"Expiry cltv %u too close to current %u",
outgoing_cltv_value,
get_block_height(ld->topology));
failmsg = towire_expiry_too_soon(tmpctx,
get_channel_update(next));
goto fail;
}
/* BOLT #4:
*
* - if the `cltv_expiry` is unreasonably far in the future:
* - return an `expiry_too_far` error.
*/
if (get_block_height(ld->topology)
+ ld->config.locktime_max < outgoing_cltv_value) {
log_debug(hin->key.channel->log,
"Expiry cltv %u too far from current %u + max %u",
outgoing_cltv_value,
get_block_height(ld->topology),
ld->config.locktime_max);
failmsg = towire_expiry_too_far(tmpctx);
goto fail;
}
failmsg = send_htlc_out(tmpctx, next, amt_to_forward,
outgoing_cltv_value, AMOUNT_MSAT(0),
&hin->payment_hash,
next_blinding, 0 /* partid */, 0 /* groupid */,
next_onion, hin, &hout);
if (!failmsg)
return;
fail:
local_fail_in_htlc(hin, failmsg);
wallet_forwarded_payment_add(ld->wallet,
hin, FORWARD_STYLE_TLV, forward_scid, hout,
FORWARD_LOCAL_FAILED,
fromwire_peektype(failmsg));
}
/**
* Data passed to the plugin, and as the context for the hook callback
*/
struct htlc_accepted_hook_payload {
struct route_step *route_step;
/* NULL if it couldn't be parsed! */
struct onion_payload *payload;
struct htlc_in *hin;
struct channel *channel;
struct lightningd *ld;
struct pubkey *next_blinding;
/* NULL if we couldn't find it */
struct channel_id *fwd_channel_id;
u8 *next_onion;
u64 failtlvtype;
size_t failtlvpos;
};
/* We only handle the simplest cases here */
static u8 *convert_failcode(const tal_t *ctx,
struct lightningd *ld,
unsigned int failure_code)
{
switch (failure_code) {
case WIRE_INVALID_REALM:
return towire_invalid_realm(ctx);
case WIRE_TEMPORARY_NODE_FAILURE:
return towire_temporary_node_failure(ctx);
case WIRE_PERMANENT_NODE_FAILURE:
return towire_permanent_node_failure(ctx);
case WIRE_REQUIRED_NODE_FEATURE_MISSING:
return towire_required_node_feature_missing(ctx);
case WIRE_PERMANENT_CHANNEL_FAILURE:
return towire_permanent_channel_failure(ctx);
case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING:
return towire_required_channel_feature_missing(ctx);
case WIRE_UNKNOWN_NEXT_PEER:
return towire_unknown_next_peer(ctx);
default:
log_broken(ld->log,
"htlc_accepted_hook plugin returned failure_code %u,"
" turning to WIRE_TEMPORARY_NODE_FAILURE",
failure_code);
return towire_temporary_node_failure(ctx);
}
}
static void
htlc_accepted_hook_try_resolve(struct htlc_accepted_hook_payload *request,
struct preimage *payment_preimage)
{
struct sha256 payment_hash;
struct htlc_in *hin = request->hin;
u8 *unknown_details;
/* Verify that the provided secret hashes to what we need. */
sha256(&payment_hash, payment_preimage, sizeof(struct preimage));
if (!sha256_eq(&payment_hash, &hin->payment_hash)) {
log_broken(
request->channel->log,
"Plugin returned a preimage (sha256(%s) = %s) that doesn't "
"match the HTLC hash (%s) it tries to resolve.",
type_to_string(tmpctx, struct preimage, payment_preimage),
type_to_string(tmpctx, struct sha256, &payment_hash),
type_to_string(tmpctx, struct sha256, &hin->payment_hash));
unknown_details = tal_arr(NULL, u8, 0);
towire_u16(&unknown_details, 0x400f);
local_fail_in_htlc(hin, take(unknown_details));
} else {
hin->we_filled = tal(hin, bool);
*hin->we_filled = true;
fulfill_htlc(hin, payment_preimage);
}
}
static u8 *prepend_length(const tal_t *ctx, const u8 *payload TAKES)
{
u8 buf[BIGSIZE_MAX_LEN], *ret;
size_t len;
len = bigsize_put(buf, tal_bytelen(payload));
ret = tal_arr(ctx, u8, len + tal_bytelen(payload));
memcpy(ret, buf, len);
memcpy(ret + len, payload, tal_bytelen(payload));
if (taken(payload))
tal_free(payload);
return ret;
}
/**
* Callback when a plugin answers to the htlc_accepted hook
*/
static bool htlc_accepted_hook_deserialize(struct htlc_accepted_hook_payload *request,
const char *buffer,
const jsmntok_t *toks)
{
struct route_step *rs = request->route_step;
struct htlc_in *hin = request->hin;
struct lightningd *ld = request->ld;
struct preimage payment_preimage;
const jsmntok_t *resulttok, *paykeytok, *payloadtok, *fwdtok;
u8 *failonion;
if (!toks || !buffer)
return true;
resulttok = json_get_member(buffer, toks, "result");
/* If the result is "continue" we can just return NULL since
* this is the default behavior for this hook anyway */
if (!resulttok) {
fatal("Plugin return value does not contain 'result' key %s",
json_strdup(tmpctx, buffer, toks));
}
payloadtok = json_get_member(buffer, toks, "payload");
if (payloadtok) {
u8 *payload = json_tok_bin_from_hex(rs, buffer, payloadtok);
if (!payload)
fatal("Bad payload for htlc_accepted"
" hook: %.*s",
payloadtok->end - payloadtok->start,
buffer + payloadtok->start);
tal_free(request->payload);
tal_free(rs->raw_payload);
rs->raw_payload = prepend_length(rs, take(payload));
request->payload = onion_decode(request,
feature_offered(ld->our_features->bits[INIT_FEATURE],
OPT_ROUTE_BLINDING),
rs,
hin->blinding,
ld->accept_extra_tlv_types,
hin->msat,
hin->cltv_expiry,
&request->failtlvtype,
&request->failtlvpos);
}
fwdtok = json_get_member(buffer, toks, "forward_to");
if (fwdtok) {
tal_free(request->fwd_channel_id);
request->fwd_channel_id = tal(request, struct channel_id);
if (!json_to_channel_id(buffer, fwdtok,
request->fwd_channel_id)) {
fatal("Bad forward_to for htlc_accepted"
" hook: %.*s",
fwdtok->end - fwdtok->start,
buffer + fwdtok->start);
}
}
if (json_tok_streq(buffer, resulttok, "continue")) {
return true;
}
if (json_tok_streq(buffer, resulttok, "fail")) {
u8 *failmsg;
const jsmntok_t *failoniontok, *failmsgtok, *failcodetok;
failoniontok = json_get_member(buffer, toks, "failure_onion");
failmsgtok = json_get_member(buffer, toks, "failure_message");
if (failoniontok) {
failonion = json_tok_bin_from_hex(tmpctx, buffer,
failoniontok);
if (!failonion)
fatal("Bad failure_onion for htlc_accepted"
" hook: %.*s",
failoniontok->end - failoniontok->start,
buffer + failoniontok->start);
if (failmsgtok)
log_broken(ld->log, "Both 'failure_onion' and"
"'failure_message' provided."
" Ignoring 'failure_message'.");
fail_in_htlc(hin, take(new_onionreply(NULL,
failonion)));
return false;
}
if (failmsgtok) {
failmsg = json_tok_bin_from_hex(NULL, buffer,
failmsgtok);
if (!failmsg)
fatal("Bad failure_message for htlc_accepted"
" hook: %.*s",
failmsgtok->end - failmsgtok->start,
buffer + failmsgtok->start);
local_fail_in_htlc(hin, take(failmsg));
return false;
} else if (deprecated_apis
&& (failcodetok = json_get_member(buffer, toks,