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lightning
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channel: support HTLC forwarding. 

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
ppa-0.6.1
Rusty Russell 8 years ago
committed by Christian Decker
parent
aa01b7d120
commit
778b756369
6 changed files with 314 additions and 36 deletions
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  1. 11
      lightningd/channel/channel.c
  2. 1
      lightningd/channel/channel_wire.csv
  3. 20
      lightningd/pay.c
  4. 261
      lightningd/peer_control.c
  5. 10
      overflows.h
  6. 41
      tests/test_lightningd.py

11
lightningd/channel/channel.c
View File

@ -644,7 +644,8 @@ static void their_htlc_locked(const struct htlc *htlc, struct peer *peer)
rs->next),
rs->nextcase == ONION_FORWARD,
rs->hoppayload->amt_to_forward,
rs->hoppayload->outgoing_cltv_value);
rs->hoppayload->outgoing_cltv_value,
rs->next->nexthop);
daemon_conn_send(&peer->master, take(msg));
tal_free(tmpctx);
return;
@ -1060,6 +1061,7 @@ static void handle_offer_htlc(struct peer *peer, const u8 *inmsg)
u32 amount_msat, cltv_expiry;
struct sha256 payment_hash;
u8 onion_routing_packet[TOTAL_PACKET_SIZE];
enum channel_add_err e;
enum onion_type failcode;
/* Subtle: must be tal_arr since we marshal using tal_len() */
const char *failmsg;
@ -1074,9 +1076,12 @@ static void handle_offer_htlc(struct peer *peer, const u8 *inmsg)
"bad offer_htlc message %s",
tal_hex(inmsg, inmsg));
switch (channel_add_htlc(peer->channel, LOCAL, peer->htlc_id,
e = channel_add_htlc(peer->channel, LOCAL, peer->htlc_id,
amount_msat, cltv_expiry, &payment_hash,
onion_routing_packet)) {
onion_routing_packet);
status_trace("Adding HTLC %"PRIu64" gave %i", peer->htlc_id, e);
switch (e) {
case CHANNEL_ERR_ADD_OK:
/* Tell the peer. */
msg = towire_update_add_htlc(peer, &peer->channel_id,

1
lightningd/channel/channel_wire.csv
View File

@ -85,6 +85,7 @@ channel_accepted_htlc,0,next_onion,1254*u8
channel_accepted_htlc,0,forward,bool
channel_accepted_htlc,0,amt_to_forward,u64
channel_accepted_htlc,0,outgoing_cltv_value,u32
channel_accepted_htlc,0,nexthop,20*u8
# FIXME: Add code to commit current channel state!

Can't render this file because it has a wrong number of fields in line 2.

20
lightningd/pay.c
View File

@ -41,18 +41,20 @@ static void json_pay_success(struct command *cmd, const struct preimage *rval)
command_success(cmd, response);
}
static void json_pay_failed(struct command *cmd,
static void json_pay_failed(struct pay_command *pc,
const struct pubkey *sender,
enum onion_type failure_code,
const char *details)
{
/* Can be NULL if JSON RPC goes away. */
if (!cmd)
if (!pc->cmd)
return;
/* FIXME: Report sender! */
command_fail(cmd, "failed: %s (%s)",
command_fail(pc->cmd, "failed: %s (%s)",
onion_type_name(failure_code), details);
pc->out = NULL;
}
void payment_succeeded(struct lightningd *ld, struct htlc_end *dst,
@ -83,9 +85,8 @@ void payment_failed(struct lightningd *ld, struct htlc_end *dst,
/* FIXME: check for routing failure / perm fail. */
/* check_for_routing_failure(i, sender, failure_code); */
json_pay_failed(dst->pay_command->cmd, sender, failure_code,
json_pay_failed(dst->pay_command, sender, failure_code,
"reply from remote");
dst->pay_command->out = NULL;
}
static bool rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds,
@ -97,14 +98,17 @@ static bool rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds,
if (!fromwire_channel_offer_htlc_reply(msg, msg, NULL,
&pc->out->htlc_id,
&failcode, &failstr)) {
json_pay_failed(pc->cmd, &subd->ld->dstate.id, -1,
json_pay_failed(pc, &subd->ld->dstate.id, -1,
"daemon bad response");
return false;
}
if (failcode != 0) {
json_pay_failed(pc->cmd, &subd->ld->dstate.id, failcode,
"from local daemon");
/* Make sure we have a nul-terminated string. */
char *str = (char *)tal_dup_arr(msg, u8,
failstr, tal_len(failstr), 1);
str[tal_len(failstr)] = 0;
json_pay_failed(pc, &subd->ld->dstate.id, failcode, str);
return true;
}

261
lightningd/peer_control.c
View File

@ -3,6 +3,7 @@
#include "subd.h"
#include <bitcoin/script.h>
#include <bitcoin/tx.h>
#include <ccan/crypto/ripemd160/ripemd160.h>
#include <ccan/io/io.h>
#include <ccan/noerr/noerr.h>
#include <ccan/take/take.h>
@ -26,6 +27,7 @@
#include <lightningd/opening/gen_opening_wire.h>
#include <lightningd/pay.h>
#include <netinet/in.h>
#include <overflows.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <wire/gen_onion_wire.h>
@ -645,9 +647,6 @@ static void fail_htlc(struct peer *peer, u64 htlc_id, const u8 *msg)
/* We don't do BADONION here */
assert(!(failcode & BADONION));
if (failcode & UPDATE) {
/* FIXME: Ask gossip daemon for channel_update. */
}
/* FIXME: encrypt msg! */
subd_send_msg(peer->owner,
@ -656,6 +655,66 @@ static void fail_htlc(struct peer *peer, u64 htlc_id, const u8 *msg)
tal_free(msg);
}
static u8 *make_failmsg(const tal_t *ctx, const struct htlc_end *hend,
enum onion_type failcode)
{
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);
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_INVALID_ONION_VERSION:
return towire_invalid_onion_version(ctx, onion_sha);
case WIRE_INVALID_ONION_HMAC:
return towire_invalid_onion_hmac(ctx, onion_sha);
case WIRE_INVALID_ONION_KEY:
return towire_invalid_onion_key(ctx, onion_sha);
case WIRE_TEMPORARY_CHANNEL_FAILURE:
return towire_temporary_channel_failure(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);
case WIRE_AMOUNT_BELOW_MINIMUM:
return towire_amount_below_minimum(ctx, hend->msatoshis, channel_update);
case WIRE_FEE_INSUFFICIENT:
return towire_fee_insufficient(ctx, hend->msatoshis, channel_update);
case WIRE_INCORRECT_CLTV_EXPIRY:
/* FIXME: ctlv! */
return towire_incorrect_cltv_expiry(ctx, 0, channel_update);
case WIRE_EXPIRY_TOO_SOON:
return towire_expiry_too_soon(ctx, channel_update);
case WIRE_UNKNOWN_PAYMENT_HASH:
return towire_unknown_payment_hash(ctx);
case WIRE_INCORRECT_PAYMENT_AMOUNT:
return towire_incorrect_payment_amount(ctx);
case WIRE_FINAL_EXPIRY_TOO_SOON:
return towire_final_expiry_too_soon(ctx);
case WIRE_FINAL_INCORRECT_CLTV_EXPIRY:
/* FIXME: ctlv! */
return towire_final_incorrect_cltv_expiry(ctx, 0);
case WIRE_FINAL_INCORRECT_HTLC_AMOUNT:
return towire_final_incorrect_htlc_amount(ctx, hend->msatoshis);
}
abort();
}
/* BOLT #4:
*
* * `amt_to_forward` - The amount in milli-satoshi to forward to the next
@ -713,13 +772,27 @@ static bool check_ctlv(struct htlc_end *hend,
return false;
}
static void fulfill_htlc(struct htlc_end *hend, const struct preimage *preimage)
{
u8 *msg;
hend->peer->balance[LOCAL] += hend->msatoshis;
hend->peer->balance[REMOTE] -= hend->msatoshis;
/* FIXME: fail the peer if it doesn't tell us that htlc fulfill is
* committed before deadline.
*/
msg = towire_channel_fulfill_htlc(hend->peer, hend->htlc_id, preimage);
subd_send_msg(hend->peer->owner, take(msg));
}
static void handle_localpay(struct htlc_end *hend,
u32 cltv_expiry,
const struct sha256 *payment_hash,
u64 amt_to_forward,
u32 outgoing_cltv_value)
{
u8 *msg, *err;
u8 *err;
struct invoice *invoice;
/* BOLT #4:
@ -789,19 +862,11 @@ static void handle_localpay(struct htlc_end *hend,
goto fail;
}
/* FIXME: fail the peer if it doesn't tell us that htlc fulfill is
* committed before deadline.
*/
connect_htlc_end(&hend->peer->ld->htlc_ends, hend);
log_info(hend->peer->ld->log, "Resolving invoice '%s' with HTLC %"PRIu64,
invoice->label, hend->htlc_id);
hend->peer->balance[LOCAL] += hend->msatoshis;
hend->peer->balance[REMOTE] -= hend->msatoshis;
msg = towire_channel_fulfill_htlc(hend->peer, hend->htlc_id, &invoice->r);
subd_send_msg(hend->peer->owner, take(msg));
fulfill_htlc(hend, &invoice->r);
resolve_invoice(&hend->peer->ld->dstate, invoice);
return;
@ -810,6 +875,71 @@ fail:
tal_free(hend);
}
static struct peer *peer_by_pkhash(struct lightningd *ld, const u8 pkhash[20])
{
struct peer *peer;
u8 addr[20];
list_for_each(&ld->peers, peer, list) {
pubkey_hash160(addr, peer->id);
if (memcmp(addr, pkhash, sizeof(addr)) == 0)
return peer;
}
return NULL;
}
/*
* 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 hend_subd_died(struct htlc_end *hend)
{
u8 *failmsg = towire_temporary_channel_failure(hend->other_end);
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);
}
static bool rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds,
struct htlc_end *hend)
{
u16 failure_code;
u8 *failurestr;
if (!fromwire_channel_offer_htlc_reply(msg, msg, NULL,
&hend->htlc_id,
&failure_code,
&failurestr)) {
log_broken(subd->log, "Bad channel_offer_htlc_reply");
tal_free(hend);
return false;
}
if (failure_code) {
log_debug(hend->other_end->peer->owner->log,
"HTLC failed from other daemon: %s (%.*s)",
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);
return true;
}
tal_del_destructor(hend, hend_subd_died);
/* Add it to lookup table. */
connect_htlc_end(&hend->peer->ld->htlc_ends, hend);
return true;
}
static void forward_htlc(struct htlc_end *hend,
u32 cltv_expiry,
const struct sha256 *payment_hash,
@ -818,7 +948,91 @@ static void forward_htlc(struct htlc_end *hend,
const u8 next_hop[20],
const u8 next_onion[TOTAL_PACKET_SIZE])
{
log_broken(hend->peer->log, "FIXME: Implement forwarding!");
u8 *err, *msg;
u64 fee;
struct lightningd *ld = hend->peer->ld;
struct peer *next = peer_by_pkhash(ld, next_hop);
if (!next) {
err = towire_unknown_next_peer(hend);
goto fail;
}
/* FIXME: These checks are horrible, use a peer flag to say it's
* ready to forward! */
if (!next->owner || !streq(next->owner->name, "lightningd_channel")
|| !streq(next->condition, "Normal operation")) {
err = towire_unknown_next_peer(hend);
goto fail;
}
/* BOLT #7:
*
* The node creating `channel_update` SHOULD accept HTLCs which pay a
* fee equal or greater than:
*
* fee-base-msat + htlc-amount-msat * fee-proportional-millionths / 1000000
*/
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);
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);
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);
goto fail;
}
/* BOLT #4:
*
* If the ctlv-expiry is too near, we tell them the the current channel
* setting for the outgoing channel:
* 1. type: UPDATE|14 (`expiry_too_soon`)
* 2. data:
* * [2:len]
* * [len:channel_update]
*/
if (get_block_height(next->ld->topology)
+ next->ld->dstate.config.deadline_blocks >= outgoing_cltv_value) {
log_debug(hend->peer->log,
"Expiry cltv %u too close to current %u + deadline %u",
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);
goto fail;
}
/* Make sure daemon owns it, in case it fails. */
hend->other_end = tal(next->owner, struct htlc_end);
hend->other_end->which_end = HTLC_DST;
hend->other_end->peer = next;
hend->other_end->other_end = hend;
hend->other_end->pay_command = NULL;
hend->other_end->msatoshis = amt_to_forward;
tal_add_destructor(hend->other_end, hend_subd_died);
msg = towire_channel_offer_htlc(next, amt_to_forward,
outgoing_cltv_value,
payment_hash, next_onion);
subd_req(next->owner, next->owner, take(msg), -1, 0,
rcvd_htlc_reply, hend->other_end);
return;
fail:
fail_htlc(hend->peer, hend->htlc_id, take(err));
tal_free(hend);
}
static int peer_accepted_htlc(struct peer *peer, const u8 *msg)
@ -837,7 +1051,8 @@ static int peer_accepted_htlc(struct peer *peer, const u8 *msg)
&cltv_expiry, &payment_hash,
next_onion, &forward,
&amt_to_forward,
&outgoing_cltv_value)) {
&outgoing_cltv_value,
next_hop)) {
log_broken(peer->log, "bad fromwire_channel_accepted_htlc %s",
tal_hex(peer, msg));
return -1;
@ -885,9 +1100,9 @@ static int peer_fulfilled_htlc(struct peer *peer, const u8 *msg)
peer->balance[REMOTE] += hend->msatoshis;
peer->balance[LOCAL] -= hend->msatoshis;
/* FIXME: Forward! */
assert(!hend->other_end);
if (hend->other_end)
fulfill_htlc(hend->other_end, &preimage);
else
payment_succeeded(peer->ld, hend, &preimage);
tal_free(hend);
@ -915,16 +1130,18 @@ static int peer_failed_htlc(struct peer *peer, const u8 *msg)
return -1;
}
/* FIXME: Decrypt reason, determine sender! */
failcode = fromwire_peektype(reason);
log_info(peer->log, "htlc %"PRIu64" failed with code 0x%04x (%s)",
id, failcode, onion_type_name(failcode));
/* FIXME: Forward! */
assert(!hend->other_end);
if (hend->other_end) {
fail_htlc(hend->other_end->peer, hend->other_end->htlc_id,
reason);
} else {
/* FIXME: Decrypt reason, determine sender! */
payment_failed(peer->ld, hend, NULL, failcode);
}
tal_free(hend);
return 0;

10
overflows.h
View File

@ -21,4 +21,14 @@ static inline bool mul_overflows_s64(int64_t a, int64_t b)
ret = a * b;
return (ret / a != b);
}
static inline bool mul_overflows_u64(uint64_t a, uint64_t b)
{
uint64_t ret;
if (a == 0)
return false;
ret = a * b;
return (ret / a != b);
}
#endif /* LIGHTNING_OVERFLOWS_H */

41
tests/test_lightningd.py
View File

@ -353,6 +353,47 @@ class LightningDTests(BaseLightningDTests):
seen.append((c['source'],c['destination']))
assert set(seen) == set(comb)
def test_forward(self):
# Connect 1 -> 2 -> 3.
l1,l2 = self.connect()
l3 = self.node_factory.get_node(legacy=False)
ret = l2.rpc.connect('localhost', l3.info['port'], l3.info['id'])
assert ret['id'] == l3.info['id']
l3.daemon.wait_for_log('WIRE_GOSSIPSTATUS_PEER_READY')
self.fund_channel(l1, l2, 10**6)
self.fund_channel(l2, l3, 10**6)
# If they're at different block heights we can get spurious errors.
sync_blockheight(l1, l2, l3)
rhash = l3.rpc.invoice(100000000, 'testpayment1')['rhash']
assert l3.rpc.listinvoice('testpayment1')[0]['complete'] == False
# Fee for node2 is 10 millionths, plus 1.
amt = 100000000
fee = amt * 10 // 1000000 + 1
# Unknown other peer
route = [ { 'msatoshi' : amt + fee, 'id' : l2.info['id'], 'delay' : 10},
{ 'msatoshi' : amt, 'id' : '031a8dc444e41bb989653a4501e11175a488a57439b0c4947704fd6e3de5dca607', 'delay' : 5} ]
self.assertRaises(ValueError, l1.rpc.sendpay, to_json(route), rhash)
# Delay too short (we always add one internally anyway, so subtract 2 here).
route = [ { 'msatoshi' : amt + fee, 'id' : l2.info['id'], 'delay' : 8},
{ 'msatoshi' : amt, 'id' : l3.info['id'], 'delay' : 5} ]
self.assertRaises(ValueError, l1.rpc.sendpay, to_json(route), rhash)
# Final delay too short
route = [ { 'msatoshi' : amt + fee, 'id' : l2.info['id'], 'delay' : 8},
{ 'msatoshi' : amt, 'id' : l3.info['id'], 'delay' : 3} ]
self.assertRaises(ValueError, l1.rpc.sendpay, to_json(route), rhash)
# This one works
route = [ { 'msatoshi' : amt + fee, 'id' : l2.info['id'], 'delay' : 10},
{ 'msatoshi' : amt, 'id' : l3.info['id'], 'delay' : 5} ]
l1.rpc.sendpay(to_json(route), rhash)
class LegacyLightningDTests(BaseLightningDTests):

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