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peer_htlcs.c
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peer_htlcs.c
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#include <bitcoin/preimage.h>
#include <bitcoin/tx.h>
#include <ccan/build_assert/build_assert.h>
#include <ccan/cast/cast.h>
#include <ccan/crypto/ripemd160/ripemd160.h>
#include <ccan/mem/mem.h>
#include <ccan/tal/str/str.h>
#include <channeld/gen_channel_wire.h>
#include <common/json_command.h>
#include <common/jsonrpc_errors.h>
#include <common/overflows.h>
#include <common/param.h>
#include <common/sphinx.h>
#include <common/timeout.h>
#include <gossipd/gen_gossip_wire.h>
#include <lightningd/chaintopology.h>
#include <lightningd/htlc_end.h>
#include <lightningd/json.h>
#include <lightningd/jsonrpc.h>
#include <lightningd/lightningd.h>
#include <lightningd/log.h>
#include <lightningd/options.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/gen_onchain_wire.h>
#include <onchaind/onchain_wire.h>
#include <wallet/wallet.h>
#include <wire/gen_onion_wire.h>
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,
hin->failcode, hin->failuremsg);
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;
wallet_htlc_update(channel->peer->ld->wallet, hout->dbid, newstate,
hout->preimage, hout->failcode, hout->failuremsg);
hout->hstate = newstate;
return true;
}
static void fail_in_htlc(struct htlc_in *hin,
enum onion_type failcode,
const u8 *failuremsg,
const struct short_channel_id *out_channelid)
{
struct failed_htlc failed_htlc;
assert(!hin->preimage);
assert(failcode || failuremsg);
hin->failcode = failcode;
if (failuremsg)
hin->failuremsg = tal_dup_arr(hin, u8, failuremsg, tal_count(failuremsg), 0);
/* We need this set, since we send it to channeld. */
if (hin->failcode & UPDATE)
hin->failoutchannel = *out_channelid;
/* 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__);
/* Tell peer, if we can. */
if (!hin->key.channel->owner)
return;
/* onchaind doesn't care, it can't do anything but wait */
if (channel_on_chain(hin->key.channel))
return;
failed_htlc.id = hin->key.id;
failed_htlc.failcode = hin->failcode;
failed_htlc.failreason = cast_const(u8 *, hin->failuremsg);
if (failed_htlc.failcode & UPDATE)
failed_htlc.scid = &hin->failoutchannel;
else
failed_htlc.scid = NULL;
subd_send_msg(hin->key.channel->owner,
take(towire_channel_fail_htlc(NULL, &failed_htlc)));
}
/* This is used for cases where we can immediately fail the HTLC. */
static void local_fail_htlc(struct htlc_in *hin, enum onion_type failcode,
const struct short_channel_id *out_channel)
{
log_info(hin->key.channel->log, "failed htlc %"PRIu64" code 0x%04x (%s)",
hin->key.id, failcode, onion_type_name(failcode));
fail_in_htlc(hin, failcode, NULL, out_channel);
}
void fail_htlc(struct htlc_in *hin, enum onion_type failcode)
{
assert(failcode);
/* Final hop never sends an UPDATE. */
assert(!(failcode & UPDATE));
local_fail_htlc(hin, failcode, NULL);
}
/* 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->failcode || hout->failuremsg);
if (hout->am_origin) {
payment_failed(hout->key.channel->peer->ld, hout, localfail);
} else if (hout->in) {
fail_in_htlc(hout->in, hout->failcode, hout->failuremsg,
hout->key.channel->scid);
}
}
/* BOLT #4:
*
* * `amt_to_forward`: The amount, in millisatoshis, to forward to the next
* receiving peer specified within the routing information.
*
* 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 either calculated according to the receiving peer's
* advertised fee schema (as described in [BOLT
* #7](07-routing-gossip.md#htlc-fees)) or is 0, if the processing node is
* the final node.
*/
static bool check_amount(struct htlc_in *hin,
struct amount_msat amt_to_forward,
struct amount_msat amt_in_htlc,
struct amount_msat fee)
{
struct amount_msat fwd;
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_onchain_known_preimage(hin, preimage);
} else {
struct fulfilled_htlc fulfilled_htlc;
fulfilled_htlc.id = hin->key.id;
fulfilled_htlc.payment_preimage = *preimage;
msg = towire_channel_fulfill_htlc(hin, &fulfilled_htlc);
}
subd_send_msg(channel->owner, take(msg));
}
static void handle_localpay(struct htlc_in *hin,
u32 cltv_expiry,
const struct sha256 *payment_hash,
struct amount_msat amt_to_forward,
u32 outgoing_cltv_value)
{
enum onion_type failcode;
struct lightningd *ld = hin->key.channel->peer->ld;
/* 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.
*/
if (!check_amount(hin, amt_to_forward, hin->msat, AMOUNT_MSAT(0))) {
failcode = WIRE_FINAL_INCORRECT_HTLC_AMOUNT;
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, cltv_expiry, outgoing_cltv_value, 0)) {
failcode = WIRE_FINAL_INCORRECT_CLTV_EXPIRY;
goto fail;
}
/* BOLT #4:
*
* - if the `cltv_expiry` value is unreasonably near the present:
* - MUST fail the HTLC.
* - MUST return a `final_expiry_too_soon` error.
*/
if (get_block_height(ld->topology) + ld->config.cltv_final
> cltv_expiry) {
log_debug(hin->key.channel->log,
"Expiry cltv too soon %u < %u + %u",
cltv_expiry,
get_block_height(ld->topology),
ld->config.cltv_final);
failcode = WIRE_FINAL_EXPIRY_TOO_SOON;
goto fail;
}
invoice_try_pay(ld, hin, payment_hash, amt_to_forward);
return;
fail:
fail_htlc(hin, failcode);
}
/*
* 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)
{
log_debug(hout->key.channel->log,
"Failing HTLC %"PRIu64" due to peer death",
hout->key.id);
hout->failcode = WIRE_TEMPORARY_CHANNEL_FAILURE;
/* Assign a temporary state (we're about to free it!) so checks
* are happy that it has a failure code */
assert(hout->hstate == SENT_ADD_HTLC);
hout->hstate = RCVD_REMOVE_HTLC;
fail_out_htlc(hout, "Outgoing subdaemon died");
}
/* 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)
{
u16 failure_code;
u8 *failurestr;
struct lightningd *ld = subd->ld;
if (!fromwire_channel_offer_htlc_reply(msg, msg,
&hout->key.id,
&failure_code,
&failurestr)) {
channel_internal_error(subd->channel,
"Bad channel_offer_htlc_reply");
tal_free(hout);
return;
}
if (failure_code) {
hout->failcode = (enum onion_type) failure_code;
if (hout->am_origin) {
char *localfail = tal_fmt(msg, "%s: %.*s",
onion_type_name(failure_code),
(int)tal_count(failurestr),
(const char *)failurestr);
payment_failed(ld, hout, localfail);
} else if (hout->in) {
local_fail_htlc(hout->in, failure_code,
hout->key.channel->scid);
/* here we haven't called connect_htlc_out(),
* so set htlc field with NULL */
wallet_forwarded_payment_add(ld->wallet,
hout->in, NULL,
FORWARD_LOCAL_FAILED,
failure_code);
}
/* 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 channel *channel)
{
/* Unset this in case we reconnect and start again. */
channel->htlc_timeout = NULL;
/* 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 too slow: killing connection");
tal_free(channel->owner);
channel_set_billboard(channel, false,
"Adding HTLC timed out: killed connection");
}
enum onion_type send_htlc_out(struct channel *out,
struct amount_msat amount, u32 cltv,
const struct sha256 *payment_hash,
const u8 *onion_routing_packet,
struct htlc_in *in,
struct htlc_out **houtp)
{
struct htlc_out *hout;
u8 *msg;
if (!channel_can_add_htlc(out)) {
log_info(out->log, "Attempt to send HTLC but not ready (%s)",
channel_state_name(out));
return WIRE_UNKNOWN_NEXT_PEER;
}
if (!out->owner) {
log_info(out->log, "Attempt to send HTLC but unowned (%s)",
channel_state_name(out));
return WIRE_TEMPORARY_CHANNEL_FAILURE;
}
if (!topology_synced(out->peer->ld->topology)) {
log_info(out->log, "Attempt to send HTLC but still syncing"
" with bitcoin network");
return WIRE_TEMPORARY_CHANNEL_FAILURE;
}
/* Make peer's daemon own it, catch if it dies. */
hout = new_htlc_out(out->owner, out, amount, cltv,
payment_hash, onion_routing_packet, in == NULL, in);
tal_add_destructor(hout, destroy_hout_subd_died);
/* Give channel 30 seconds to commit (first) htlc. */
if (!out->htlc_timeout)
out->htlc_timeout = new_reltimer(out->peer->ld->timers,
out, time_from_sec(30),
htlc_offer_timeout,
out);
msg = towire_channel_offer_htlc(out, amount, cltv, payment_hash,
onion_routing_packet);
subd_req(out->peer->ld, out->owner, take(msg), -1, 0, rcvd_htlc_reply, hout);
if (houtp)
*houtp = hout;
return 0;
}
static void forward_htlc(struct htlc_in *hin,
u32 cltv_expiry,
struct amount_msat amt_to_forward,
u32 outgoing_cltv_value,
const struct node_id *next_hop,
const u8 next_onion[TOTAL_PACKET_SIZE])
{
enum onion_type failcode;
struct amount_msat fee;
struct lightningd *ld = hin->key.channel->peer->ld;
struct channel *next = active_channel_by_id(ld, next_hop, NULL);
struct htlc_out *hout = NULL;
/* Unknown peer, or peer not ready. */
if (!next || !next->scid) {
local_fail_htlc(hin, WIRE_UNKNOWN_NEXT_PEER, NULL);
wallet_forwarded_payment_add(hin->key.channel->peer->ld->wallet,
hin, NULL,
FORWARD_LOCAL_FAILED,
hin->failcode);
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 (!amount_msat_fee(&fee, amt_to_forward,
next->feerate_base,
next->feerate_ppm)) {
log_broken(ld->log, "Fee overflow forwarding %s!",
type_to_string(tmpctx, struct amount_msat,
&amt_to_forward));
failcode = WIRE_FEE_INSUFFICIENT;
goto fail;
}
if (!check_amount(hin, amt_to_forward, hin->msat, fee)) {
failcode = WIRE_FEE_INSUFFICIENT;
goto fail;
}
if (!check_cltv(hin, cltv_expiry, outgoing_cltv_value,
ld->config.cltv_expiry_delta)) {
failcode = WIRE_INCORRECT_CLTV_EXPIRY;
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));
failcode = WIRE_EXPIRY_TOO_SOON;
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);
failcode = WIRE_EXPIRY_TOO_FAR;
goto fail;
}
hout = tal(tmpctx, struct htlc_out);
failcode = send_htlc_out(next, amt_to_forward,
outgoing_cltv_value, &hin->payment_hash,
next_onion, hin, &hout);
if (!failcode)
return;
/* In fact, we didn't get the new htlc_out in these 2 cases */
if (failcode == WIRE_UNKNOWN_NEXT_PEER ||
failcode == WIRE_TEMPORARY_CHANNEL_FAILURE) {
tal_free(hout);
hout = NULL;
}
fail:
local_fail_htlc(hin, failcode, next->scid);
wallet_forwarded_payment_add(ld->wallet,
hin, hout,
FORWARD_LOCAL_FAILED,
hin->failcode);
}
/* Temporary information, while we resolve the next hop */
struct gossip_resolve {
struct short_channel_id next_channel;
struct amount_msat amt_to_forward;
u32 outgoing_cltv_value;
u8 *next_onion;
struct htlc_in *hin;
};
/* We received a resolver reply, which gives us the node_ids of the
* channel we want to forward over */
static void channel_resolve_reply(struct subd *gossip, const u8 *msg,
const int *fds UNUSED, struct gossip_resolve *gr)
{
struct node_id *peer_id;
if (!fromwire_gossip_get_channel_peer_reply(msg, msg, &peer_id)) {
log_broken(gossip->log,
"bad fromwire_gossip_get_channel_peer_reply %s",
tal_hex(msg, msg));
return;
}
if (!peer_id) {
local_fail_htlc(gr->hin, WIRE_UNKNOWN_NEXT_PEER, NULL);
wallet_forwarded_payment_add(gr->hin->key.channel->peer->ld->wallet,
gr->hin, NULL,
FORWARD_LOCAL_FAILED,
gr->hin->failcode);
tal_free(gr);
return;
}
forward_htlc(gr->hin, gr->hin->cltv_expiry,
gr->amt_to_forward, gr->outgoing_cltv_value, peer_id,
gr->next_onion);
tal_free(gr);
}
/**
* Data passed to the plugin, and as the context for the hook callback
*/
struct htlc_accepted_hook_payload {
struct route_step *route_step;
struct htlc_in *hin;
struct channel *channel;
struct lightningd *ld;
u8 *next_onion;
};
/* The possible return value types that a plugin may return for the
* `htlc_accepted` hook. */
enum htlc_accepted_result {
htlc_accepted_continue,
htlc_accepted_fail,
htlc_accepted_resolve,
};
/**
* Parses the JSON-RPC response into a struct understood by the callback.
*/
static enum htlc_accepted_result htlc_accepted_hook_deserialize(const char *buffer, const jsmntok_t *toks,
/* If accepted */
struct preimage *payment_preimage,
/* If rejected */
enum onion_type *failure_code,
u8 **channel_update)
{
const jsmntok_t *resulttok, *failcodetok, *paykeytok, *chanupdtok;
enum htlc_accepted_result result;
if (!toks || !buffer)
return htlc_accepted_continue;
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));
}
if (json_tok_streq(buffer, resulttok, "continue")) {
return htlc_accepted_continue;
}
if (json_tok_streq(buffer, resulttok, "fail")) {
result = htlc_accepted_fail;
failcodetok = json_get_member(buffer, toks, "failure_code");
chanupdtok = json_get_member(buffer, toks, "channel_update");
if (failcodetok &&
!json_to_number(buffer, failcodetok, failure_code))
fatal("Plugin provided a non-numeric failcode "
"in response to an htlc_accepted hook");
if (!failcodetok)
*failure_code = WIRE_TEMPORARY_NODE_FAILURE;
if (chanupdtok)
*channel_update =
json_tok_bin_from_hex(buffer, buffer, chanupdtok);
else
*channel_update = NULL;
} else if (json_tok_streq(buffer, resulttok, "resolve")) {
result = htlc_accepted_resolve;
paykeytok = json_get_member(buffer, toks, "payment_key");
if (!paykeytok)
fatal(
"Plugin did not specify a 'payment_key' in return "
"value to the htlc_accepted hook: %s",
json_strdup(tmpctx, buffer, resulttok));
if (!json_to_preimage(buffer, paykeytok,
payment_preimage))
fatal("Plugin specified an invalid 'payment_key': %s",
json_tok_full(buffer, resulttok));
} else {
fatal("Plugin responded with an unknown result to the "
"htlc_accepted hook: %s",
json_strdup(tmpctx, buffer, resulttok));
}
return result;
}
static void htlc_accepted_hook_serialize(struct htlc_accepted_hook_payload *p,
struct json_stream *s)
{
const struct route_step *rs = p->route_step;
const struct htlc_in *hin = p->hin;
s32 expiry = hin->cltv_expiry, blockheight = p->ld->topology->tip->height;
json_object_start(s, "onion");
json_add_hex_talarr (s, "payload", rs->raw_payload);
if (rs->type == SPHINX_V0_PAYLOAD) {
json_object_start(s, "per_hop_v0");
json_add_string(s, "realm", "00");
json_add_short_channel_id(s, "short_channel_id", &rs->payload.v0.channel_id);
json_add_amount_msat_only(s, "forward_amount", rs->payload.v0.amt_forward);
json_add_u64(s, "outgoing_cltv_value", rs->payload.v0.outgoing_cltv);
json_object_end(s);
}
json_add_hex_talarr(s, "next_onion", p->next_onion);
json_add_secret(s, "shared_secret", hin->shared_secret);
json_object_end(s);
json_object_start(s, "htlc");
json_add_amount_msat_only(s, "amount", hin->msat);
json_add_u32(s, "cltv_expiry", expiry);
json_add_s32(s, "cltv_expiry_relative", expiry - blockheight);
json_add_sha256(s, "payment_hash", &hin->payment_hash);
json_object_end(s);
}
/**
* Callback when a plugin answers to the htlc_accepted hook
*/
static void
htlc_accepted_hook_callback(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 channel *channel = request->channel;
struct lightningd *ld = request->ld;
struct preimage payment_preimage;
u8 *req;
enum htlc_accepted_result result;
enum onion_type failure_code;
u8 *channel_update;
struct hop_data *hop_data;
result = htlc_accepted_hook_deserialize(buffer, toks, &payment_preimage, &failure_code, &channel_update);
hop_data = &rs->payload.v0;
switch (result) {
case htlc_accepted_continue:
if (rs->nextcase == ONION_FORWARD) {
struct gossip_resolve *gr = tal(ld, struct gossip_resolve);
gr->next_onion = serialize_onionpacket(gr, rs->next);
gr->next_channel = hop_data->channel_id;
gr->amt_to_forward = hop_data->amt_forward;
gr->outgoing_cltv_value = hop_data->outgoing_cltv;
gr->hin = hin;
req = towire_gossip_get_channel_peer(tmpctx, &gr->next_channel);
log_debug(channel->log, "Asking gossip to resolve channel %s",
type_to_string(tmpctx, struct short_channel_id,
&gr->next_channel));
subd_req(hin, ld->gossip, req, -1, 0,
channel_resolve_reply, gr);
} else
handle_localpay(hin, hin->cltv_expiry, &hin->payment_hash,
hop_data->amt_forward,
hop_data->outgoing_cltv);
break;
case htlc_accepted_fail:
log_debug(channel->log,
"Failing incoming HTLC as instructed by plugin hook");
fail_in_htlc(hin, failure_code, NULL, &hop_data->channel_id);
break;
case htlc_accepted_resolve:
fulfill_htlc(hin, &payment_preimage);
break;
}
tal_free(request);
}
REGISTER_PLUGIN_HOOK(htlc_accepted, htlc_accepted_hook_callback,
struct htlc_accepted_hook_payload *,
htlc_accepted_hook_serialize,
struct htlc_accepted_hook_payload *);
/**
* Everyone is committed to this htlc of theirs
*
* @param channel: The channel this HTLC was accepted from.
* @param id: the ID of the HTLC we accepted
* @param replay: Are we loading from the database and therefore should not
* perform the transition to RCVD_ADD_ACK_REVOCATION?
* @param[out] failcode: If we decide to fail right away this will be set to a
* non-zero failcode.
*/
static bool peer_accepted_htlc(struct channel *channel, u64 id,
bool replay, enum onion_type *failcode)
{
struct htlc_in *hin;
struct route_step *rs;
struct onionpacket *op;
struct lightningd *ld = channel->peer->ld;
struct htlc_accepted_hook_payload *hook_payload;
hin = find_htlc_in(&ld->htlcs_in, channel, id);
if (!hin) {
channel_internal_error(channel,
"peer_got_revoke unknown htlc %"PRIu64, id);
return false;
}
if (!replay && !htlc_in_update_state(channel, hin, RCVD_ADD_ACK_REVOCATION))
return false;
htlc_in_check(hin, __func__);
#if DEVELOPER
if (channel->peer->ignore_htlcs) {
log_debug(channel->log, "their htlc %"PRIu64" dev_ignore_htlcs",
id);
return true;
}
#endif
/* BOLT #2:
*
* - SHOULD fail to route any HTLC added after it has sent `shutdown`.
*/
if (channel->state == CHANNELD_SHUTTING_DOWN) {
*failcode = WIRE_PERMANENT_CHANNEL_FAILURE;
goto out;
}
/* BOLT #2:
*
* A fulfilling node:
* - for each HTLC it is attempting to fulfill:
* - MUST estimate a fulfillment deadline.
* - MUST fail (and not forward) an HTLC whose fulfillment deadline is
* already past.
*/
/* Our deadline is half the cltv_delta we insist on, so this check is
* a subset of the cltv check done in handle_localpay and
* forward_htlc. */
/* Channeld sets this to NULL if couldn't parse onion */
if (!hin->shared_secret) {
*failcode = WIRE_INVALID_ONION_KEY;
goto out;
}
/* FIXME: Have channeld hand through just the route_step! */
/* channeld tests this, so it should pass. */
op = parse_onionpacket(tmpctx, hin->onion_routing_packet,
sizeof(hin->onion_routing_packet),
failcode);
if (!op) {
channel_internal_error(channel,
"bad onion in got_revoke: %s",
tal_hexstr(channel, hin->onion_routing_packet,
sizeof(hin->onion_routing_packet)));
return false;
}
/* If it's crap, not channeld's fault, just fail it */
rs = process_onionpacket(tmpctx, op, hin->shared_secret->data,
hin->payment_hash.u.u8,
sizeof(hin->payment_hash));
if (!rs) {
channel_internal_error(channel,
"bad process_onionpacket in got_revoke: %s",
tal_hexstr(channel, hin->onion_routing_packet,
sizeof(hin->onion_routing_packet)));
return false;
}
/* Unknown realm isn't a bad onion, it's a normal failure. */
/* FIXME: if we want hooks to handle foreign realms we should
* move this check to the hook callback. */
if (rs->type != SPHINX_V0_PAYLOAD) {
*failcode = WIRE_INVALID_REALM;
goto out;
}
/* It's time to package up all the information and call the
* hook so plugins can interject if they want */
hook_payload = tal(hin, struct htlc_accepted_hook_payload);
hook_payload->route_step = tal_steal(hook_payload, rs);
hook_payload->ld = ld;
hook_payload->hin = hin;
hook_payload->channel = channel;
hook_payload->next_onion = serialize_onionpacket(hook_payload, rs->next);
plugin_hook_call_htlc_accepted(ld, hook_payload, hook_payload);
/* Falling through here is ok, after all the HTLC locked */
*failcode = 0;
out:
log_debug(channel->log, "their htlc %"PRIu64" %s",
id, *failcode ? onion_type_name(*failcode) : "locked");
return true;
}
static void fulfill_our_htlc_out(struct channel *channel, struct htlc_out *hout,
const struct preimage *preimage)
{
struct lightningd *ld = channel->peer->ld;
assert(!hout->preimage);
hout->preimage = tal_dup(hout, struct preimage, preimage);
htlc_out_check(hout, __func__);
wallet_htlc_update(ld->wallet, hout->dbid, hout->hstate,
hout->preimage, hout->failcode, hout->failuremsg);
/* Update channel stats */
wallet_channel_stats_incr_out_fulfilled(ld->wallet,
channel->dbid,
hout->msat);
if (hout->am_origin)
payment_succeeded(ld, hout, preimage);
else if (hout->in) {
fulfill_htlc(hout->in, preimage);
wallet_forwarded_payment_add(ld->wallet, hout->in, hout,
FORWARD_SETTLED, 0);
}
}
static bool peer_fulfilled_our_htlc(struct channel *channel,
const struct fulfilled_htlc *fulfilled)
{
struct lightningd *ld = channel->peer->ld;
struct htlc_out *hout;
hout = find_htlc_out(&ld->htlcs_out, channel, fulfilled->id);
if (!hout) {
channel_internal_error(channel,
"fulfilled_our_htlc unknown htlc %"PRIu64,
fulfilled->id);
return false;
}
if (!htlc_out_update_state(channel, hout, RCVD_REMOVE_COMMIT))
return false;
fulfill_our_htlc_out(channel, hout, &fulfilled->payment_preimage);
return true;
}
void onchain_fulfilled_htlc(struct channel *channel,
const struct preimage *preimage)
{
struct htlc_out_map_iter outi;
struct htlc_out *hout;
struct sha256 payment_hash;
struct lightningd *ld = channel->peer->ld;
sha256(&payment_hash, preimage, sizeof(*preimage));
/* FIXME: use db to look this up! */
for (hout = htlc_out_map_first(&ld->htlcs_out, &outi);
hout;
hout = htlc_out_map_next(&ld->htlcs_out, &outi)) {
if (hout->key.channel != channel)
continue;
/* It's possible that we failed some and succeeded one,
* if we got multiple errors. */
if (hout->failcode != 0 || hout->failuremsg)
continue;
if (!sha256_eq(&hout->payment_hash, &payment_hash))
continue;
/* We may have already fulfilled before going onchain, or
* we can fulfill onchain multiple times. */
if (!hout->preimage) {
/* Force state to something which allows a preimage */
hout->hstate = RCVD_REMOVE_HTLC;
fulfill_our_htlc_out(channel, hout, preimage);
}
/* We keep going: this is something of a leak, but onchain
* we have no real way of distinguishing HTLCs anyway */
}