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routing: Ask gossipd to resolve channel_id and forward HTLCs

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Since we now use the short_channel_id to identify the next hop we need
to resolve the channel_id to the pubkey of the next hop. This is done
by calling out to `gossipd` and stuffing the necessary information
into `htlc_end` and recovering it from there once we receive a reply.
This commit is contained in:
Christian Decker
2017-04-30 23:49:15 +02:00
parent b9dcb909b8
commit 25f1cba3cf
7 changed files with 100 additions and 34 deletions
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76
lightningd/peer_control.c
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@@ -875,14 +875,11 @@ fail:
tal_free(hend);
}
static struct peer *peer_by_pkhash(struct lightningd *ld, const u8 pkhash[20])
static struct peer *peer_by_pubkey(struct lightningd *ld, const struct pubkey *id)
{
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)
if (pubkey_cmp(id, peer->id) == 0)
return peer;
}
return NULL;
@@ -945,13 +942,13 @@ static void forward_htlc(struct htlc_end *hend,
const struct sha256 *payment_hash,
u64 amt_to_forward,
u32 outgoing_cltv_value,
const u8 next_hop[20],
const struct pubkey *next_hop,
const u8 next_onion[TOTAL_PACKET_SIZE])
{
u8 *err, *msg;
u64 fee;
struct lightningd *ld = hend->peer->ld;
struct peer *next = peer_by_pkhash(ld, next_hop);
struct peer *next = peer_by_pubkey(ld, next_hop);
if (!next) {
err = towire_unknown_next_peer(hend);
@@ -1035,44 +1032,63 @@ fail:
tal_free(hend);
}
/* We received a resolver reply, which gives us the node_ids of the
* channel we want to forward over */
static bool channel_resolve_reply(struct subd *gossip, const u8 *msg,
const int *fds, struct htlc_end *hend)
{
struct pubkey node_id_1, node_id_2, peer_id;
u8 error;
fromwire_gossip_resolve_channel_reply(msg, NULL, &error, &node_id_1,
&node_id_2);
/* Get the other peer matching the id that is not us */
if (pubkey_cmp(&node_id_1, &gossip->ld->dstate.id) == 0) {
peer_id = node_id_2;
} else {
peer_id = node_id_1;
}
forward_htlc(hend, hend->cltv_expiry, &hend->payment_hash,
hend->amt_to_forward, hend->outgoing_cltv_value, &peer_id,
hend->next_onion);
/* FIXME(cdecker) Cleanup things we stuffed into hend before (maybe?) */
return true;
}
static int peer_accepted_htlc(struct peer *peer, const u8 *msg)
{
u64 id;
u32 cltv_expiry, amount_msat;
struct sha256 payment_hash;
u8 next_onion[TOTAL_PACKET_SIZE];
u8 next_hop[20];
bool forward;
u64 amt_to_forward;
u32 outgoing_cltv_value;
struct htlc_end *hend;
u8 *req;
if (!fromwire_channel_accepted_htlc(msg, NULL, &id, &amount_msat,
&cltv_expiry, &payment_hash,
next_onion, &forward,
&amt_to_forward,
&outgoing_cltv_value,
next_hop)) {
hend = tal(msg, struct htlc_end);
if (!fromwire_channel_accepted_htlc(msg, NULL,
&hend->htlc_id, &hend->msatoshis,
&hend->cltv_expiry, &hend->payment_hash,
hend->next_onion, &forward,
&hend->amt_to_forward,
&hend->outgoing_cltv_value,
&hend->next_channel)) {
log_broken(peer->log, "bad fromwire_channel_accepted_htlc %s",
tal_hex(peer, msg));
return -1;
}
hend = tal(peer, struct htlc_end);
tal_steal(peer, hend);
hend->which_end = HTLC_SRC;
hend->peer = peer;
hend->htlc_id = id;
hend->other_end = NULL;
hend->pay_command = NULL;
hend->msatoshis = amount_msat;
if (forward)
forward_htlc(hend, cltv_expiry, &payment_hash,
amt_to_forward, outgoing_cltv_value,
next_hop, next_onion);
else
handle_localpay(hend, cltv_expiry, &payment_hash,
amt_to_forward, outgoing_cltv_value);
if (forward) {
req = towire_gossip_resolve_channel_request(msg, &hend->next_channel);
log_broken(peer->log, "Asking gossip to resolve channel %d/%d/%d", hend->next_channel.blocknum, hend->next_channel.txnum, hend->next_channel.outnum);
subd_req(hend, peer->ld->gossip, req, -1, 0, channel_resolve_reply, hend);
/* FIXME(cdecker) Stuff all this info into hend */
} else
handle_localpay(hend, hend->cltv_expiry, &hend->payment_hash,
hend->amt_to_forward, hend->outgoing_cltv_value);
return 0;
}