core-lightning/lightningd/routehint.c
Rusty Russell 2be1f3fe1b lightningd: extract routehint selection code.
We're going to want this for bolt13 formation as well.

As a result of reworking the logic into "candidate selection" then
"route hint selection", we need to change the way round-robin works.
We use a simple incrementing index now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2020-09-08 19:47:11 +09:30

135 lines
3.6 KiB
C

#include <common/bolt11.h>
#include <common/utils.h>
#include <gossipd/gossipd_wiregen.h>
#include <lightningd/log.h>
#include <lightningd/peer_control.h>
#include <lightningd/routehint.h>
static void append_routes(struct route_info **dst, const struct route_info *src)
{
size_t n = tal_count(*dst);
tal_resize(dst, n + tal_count(src));
memcpy(*dst + n, src, tal_count(src) * sizeof(*src));
}
static void append_bools(bool **dst, const bool *src)
{
size_t n = tal_count(*dst);
tal_resize(dst, n + tal_count(src));
memcpy(*dst + n, src, tal_count(src) * sizeof(*src));
}
static bool scid_in_arr(const struct short_channel_id *scidarr,
const struct short_channel_id *scid)
{
for (size_t i = 0; i < tal_count(scidarr); i++)
if (short_channel_id_eq(&scidarr[i], scid))
return true;
return false;
}
struct routehint_candidate *
routehint_candidates(const tal_t *ctx,
struct lightningd *ld,
const u8 *incoming_channels_reply,
bool expose_all_private,
const struct short_channel_id *hints,
bool *none_public,
bool *deadends,
struct amount_msat *amount_offline)
{
struct routehint_candidate *candidates;
struct route_info *inchans, *private;
bool *inchan_deadends, *private_deadends;
if (!fromwire_gossipd_get_incoming_channels_reply(tmpctx,
incoming_channels_reply,
&inchans,
&inchan_deadends,
&private,
&private_deadends))
fatal("Gossip gave bad GOSSIPD_GET_INCOMING_CHANNELS_REPLY %s",
tal_hex(tmpctx, incoming_channels_reply));
*none_public = (tal_count(inchans) == 0) && (tal_count(private) > 0);
*deadends = false;
/* fromwire explicitly makes empty arrays into NULL */
if (!inchans) {
inchans = tal_arr(tmpctx, struct route_info, 0);
inchan_deadends = tal_arr(tmpctx, bool, 0);
}
if (expose_all_private) {
append_routes(&inchans, private);
append_bools(&inchan_deadends, private_deadends);
} else if (hints) {
/* Start by considering all channels as candidates */
append_routes(&inchans, private);
append_bools(&inchan_deadends, private_deadends);
/* Consider only hints they gave */
for (size_t i = 0; i < tal_count(inchans); i++) {
if (!scid_in_arr(hints,
&inchans[i].short_channel_id)) {
tal_arr_remove(&inchans, i);
tal_arr_remove(&inchan_deadends, i);
i--;
} else
/* If they specify directly, we don't
* care if it's a deadend */
inchan_deadends[i] = false;
}
} else {
assert(!hints);
/* By default, only consider private channels if there are
* no public channels *at all* */
if (tal_count(inchans) == 0) {
append_routes(&inchans, private);
append_bools(&inchan_deadends, private_deadends);
}
}
candidates = tal_arr(ctx, struct routehint_candidate, 0);
*amount_offline = AMOUNT_MSAT(0);
for (size_t i = 0; i < tal_count(inchans); i++) {
struct peer *peer;
struct routehint_candidate candidate;
/* Do we know about this peer? */
peer = peer_by_id(ld, &inchans[i].pubkey);
if (!peer)
continue;
/* Does it have a channel in state CHANNELD_NORMAL */
candidate.c = peer_normal_channel(peer);
if (!candidate.c)
continue;
/* Is it a dead-end? */
if (inchan_deadends[i]) {
*deadends = true;
continue;
}
candidate.capacity = channel_amount_receivable(candidate.c);
/* Is it offline? */
if (candidate.c->owner == NULL) {
if (!amount_msat_add(amount_offline,
*amount_offline,
candidate.capacity))
fatal("Overflow summing offline capacity!");
continue;
}
candidate.r = &inchans[i];
tal_arr_expand(&candidates, candidate);
}
return candidates;
}