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routing: work with struct routing_channel not struct node_connection.

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To remove the redundant fields in `struct node_connection` (ie. 'src'
and 'dst' pointers) we need to deal with `struct routing_channel`.
This means we get a series of channels, from which the direction is
implied, so it's a bit more complex to decode.  We add a helper
`other_node` to help with this, and since we're the only user of
`connection_to` we change that function to return the index.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2018-03-04 12:53:32 +10:30 committed by Christian Decker
parent 31b9b6bc1c
commit 56349ab008
5 changed files with 104 additions and 80 deletions
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93
gossipd/routing.c
View File

@ -303,16 +303,16 @@ static u64 risk_fee(u64 amount, u32 delay, double riskfactor)
/* We track totals, rather than costs. That's because the fee depends
* on the current amount passing through. */
static void bfg_one_edge(struct node *node,
struct node_connection *c, double riskfactor,
struct routing_channel *chan, int idx,
double riskfactor,
double fuzz, const struct siphash_seed *base_seed)
{
size_t h;
double fee_scale = 1.0;
const struct node_connection *c = &chan->connections[idx];
if (fuzz != 0.0) {
u64 h = siphash24(base_seed,
&c->short_channel_id,
sizeof(c->short_channel_id));
u64 h = siphash24(base_seed, &chan->scid, sizeof(chan->scid));
/* Scale fees for this channel */
/* rand = (h / UINT64_MAX) random number between 0.0 -> 1.0
@ -322,8 +322,8 @@ static void bfg_one_edge(struct node *node,
fee_scale = 1.0 + (2.0 * fuzz * h / UINT64_MAX) - fuzz;
}
assert(c->dst == node);
for (h = 0; h < ROUTING_MAX_HOPS; h++) {
struct node *src;
/* FIXME: Bias against smaller channels. */
u64 fee;
u64 risk;
@ -343,15 +343,17 @@ static void bfg_one_edge(struct node *node,
continue;
}
/* nodes[0] is src for connections[0] */
src = chan->nodes[idx];
if (node->bfg[h].total + fee + risk
< c->src->bfg[h+1].total + c->src->bfg[h+1].risk) {
< src->bfg[h+1].total + src->bfg[h+1].risk) {
SUPERVERBOSE("...%s can reach here in hoplen %zu total %"PRIu64,
type_to_string(trc, struct pubkey,
&c->src->id),
&src->id),
h, node->bfg[h].total + fee);
c->src->bfg[h+1].total = node->bfg[h].total + fee;
c->src->bfg[h+1].risk = risk;
c->src->bfg[h+1].prev = c;
src->bfg[h+1].total = node->bfg[h].total + fee;
src->bfg[h+1].risk = risk;
src->bfg[h+1].prev = chan;
}
}
}
@ -363,16 +365,16 @@ static bool nc_is_routable(const struct node_connection *nc, time_t now)
}
/* riskfactor is already scaled to per-block amount */
static struct node_connection *
static struct routing_channel *
find_route(const tal_t *ctx, struct routing_state *rstate,
const struct pubkey *from, const struct pubkey *to, u64 msatoshi,
double riskfactor,
double fuzz, const struct siphash_seed *base_seed,
u64 *fee, struct node_connection ***route)
u64 *fee, struct routing_channel ***route)
{
struct node *n, *src, *dst;
struct node_map_iter it;
struct node_connection *first_conn;
struct routing_channel *first_chan;
int runs, i, best;
/* Call time_now() once at the start, so that our tight loop
* does not keep calling into operating system for the
@ -420,18 +422,20 @@ find_route(const tal_t *ctx, struct routing_state *rstate,
n = node_map_next(rstate->nodes, &it)) {
size_t num_edges = tal_count(n->channels);
for (i = 0; i < num_edges; i++) {
struct node_connection *c;
struct routing_channel *chan = n->channels[i];
int idx = connection_to(n, chan);
SUPERVERBOSE("Node %s edge %i/%zu",
type_to_string(trc, struct pubkey,
&n->id),
i, num_edges);
c = connection_to(n, n->channels[i]);
if (!nc_is_routable(c, now)) {
if (!nc_is_routable(&chan->connections[idx],
now)) {
SUPERVERBOSE("...unroutable");
continue;
}
bfg_one_edge(n, c,
bfg_one_edge(n, chan, idx,
riskfactor, fuzz, base_seed);
SUPERVERBOSE("...done");
}
@ -454,37 +458,20 @@ find_route(const tal_t *ctx, struct routing_state *rstate,
/* Save route from *next* hop (we return first hop as peer).
* Note that we take our own fees into account for routing, even
* though we don't pay them: it presumably effects preference. */
first_conn = dst->bfg[best].prev;
dst = dst->bfg[best].prev->dst;
first_chan = dst->bfg[best].prev;
dst = other_node(dst, dst->bfg[best].prev);
best--;
*fee = dst->bfg[best].total - msatoshi;
*route = tal_arr(ctx, struct node_connection *, best);
*route = tal_arr(ctx, struct routing_channel *, best);
for (i = 0, n = dst;
i < best;
n = n->bfg[best-i].prev->dst, i++) {
n = other_node(n, n->bfg[best-i].prev), i++) {
(*route)[i] = n->bfg[best-i].prev;
}
assert(n == src);
msatoshi += *fee;
status_trace("find_route: via %s",
type_to_string(trc, struct pubkey, &first_conn->dst->id));
/* If there are intermediaries, dump them, and total fees. */
if (best != 0) {
for (i = 0; i < best; i++) {
status_trace(" %s (%i+%i=%"PRIu64")",
type_to_string(trc, struct pubkey,
&(*route)[i]->dst->id),
(*route)[i]->base_fee,
(*route)[i]->proportional_fee,
connection_fee((*route)[i], msatoshi));
msatoshi -= connection_fee((*route)[i], msatoshi);
}
status_trace(" =%"PRIi64"(%+"PRIi64")",
(*route)[best-1]->dst->bfg[best-1].total, *fee);
}
return first_conn;
return first_chan;
}
/* Verify the signature of a channel_update message */
@ -1084,20 +1071,22 @@ struct route_hop *get_route(tal_t *ctx, struct routing_state *rstate,
u32 final_cltv,
double fuzz, const struct siphash_seed *base_seed)
{
struct node_connection **route;
struct routing_channel **route;
u64 total_amount;
unsigned int total_delay;
u64 fee;
struct route_hop *hops;
int i;
struct node_connection *first_conn;
struct routing_channel *first_chan;
struct node *n;
first_conn = find_route(ctx, rstate, source, destination, msatoshi,
/* FIXME: make find_route simply return entire route array! */
first_chan = find_route(ctx, rstate, source, destination, msatoshi,
riskfactor / BLOCKS_PER_YEAR / 10000,
fuzz, base_seed,
&fee, &route);
if (!first_conn) {
if (!first_chan) {
return NULL;
}
@ -1106,18 +1095,24 @@ struct route_hop *get_route(tal_t *ctx, struct routing_state *rstate,
total_amount = msatoshi;
total_delay = final_cltv;
/* Start at destination node. */
n = get_node(rstate, destination);
for (i = tal_count(route) - 1; i >= 0; i--) {
hops[i + 1].channel_id = route[i]->short_channel_id;
hops[i + 1].nodeid = route[i]->dst->id;
const struct node_connection *c;
int idx = connection_to(n, route[i]);
c = &route[i]->connections[idx];
hops[i + 1].channel_id = route[i]->scid;
hops[i + 1].nodeid = n->id;
hops[i + 1].amount = total_amount;
total_amount += connection_fee(route[i], total_amount);
total_amount += connection_fee(c, total_amount);
hops[i + 1].delay = total_delay;
total_delay += route[i]->delay;
total_delay += c->delay;
n = route[i]->nodes[!idx];
}
/* Backfill the first hop manually */
hops[0].channel_id = first_conn->short_channel_id;
hops[0].nodeid = first_conn->dst->id;
hops[0].channel_id = first_chan->scid;
hops[0].nodeid = n->id;
/* We don't charge ourselves any fees, nor require delay */
hops[0].amount = total_amount;
hops[0].delay = total_delay;

16
gossipd/routing.h
View File

@ -66,7 +66,7 @@ struct node {
/* Total risk premium of this route. */
u64 risk;
/* Where that came from. */
struct node_connection *prev;
struct routing_channel *prev;
} bfg[ROUTING_MAX_HOPS+1];
/* UTF-8 encoded alias as tal_arr, not zero terminated */
@ -118,6 +118,14 @@ static inline int pubkey_idx(const struct pubkey *id1, const struct pubkey *id2)
return pubkey_cmp(id1, id2) > 0;
}
static inline struct node *other_node(const struct node *n,
struct routing_channel *chan)
{
int idx = (chan->nodes[1] == n);
return chan->nodes[!idx];
}
/* FIXME: We could avoid these by having two channels arrays */
static inline struct node_connection *connection_from(const struct node *n,
struct routing_channel *chan)
@ -129,14 +137,14 @@ static inline struct node_connection *connection_from(const struct node *n,
return &chan->connections[idx];
}
static inline struct node_connection *connection_to(const struct node *n,
struct routing_channel *chan)
static inline int connection_to(const struct node *n,
struct routing_channel *chan)
{
int idx = (chan->nodes[1] == n);
assert(chan->connections[idx].src == n);
assert(chan->connections[!idx].dst == n);
return &chan->connections[!idx];
return !idx;
}
struct routing_state {

14
gossipd/test/run-bench-find_route.c
View File

@ -218,14 +218,14 @@ int main(int argc, char *argv[])
struct pubkey from = nodeid(pseudorand(num_nodes));
struct pubkey to = nodeid(pseudorand(num_nodes));
u64 fee;
struct node_connection **route = NULL, *nc;
struct routing_channel **route = NULL, *chan;
nc = find_route(ctx, rstate, &from, &to,
pseudorand(100000),
riskfactor,
0.75, &base_seed,
&fee, &route);
num_success += (nc != NULL);
chan = find_route(ctx, rstate, &from, &to,
pseudorand(100000),
riskfactor,
0.75, &base_seed,
&fee, &route);
num_success += (chan != NULL);
tal_free(route);
}
end = time_mono();

17
gossipd/test/run-find_route-specific.c
View File

@ -94,7 +94,8 @@ int main(void)
struct routing_state *rstate;
struct pubkey a, b, c;
u64 fee;
struct node_connection **route;
struct routing_channel **route;
struct routing_channel *first;
const double riskfactor = 1.0 / BLOCKS_PER_YEAR / 10000;
secp256k1_ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY
@ -148,11 +149,17 @@ int main(void)
nc->flags = 1;
nc->last_timestamp = 1504064344;
nc = find_route(ctx, rstate, &a, &c, 100000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &c, 100000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 1);
assert(pubkey_eq(&route[0]->src->id, &b));
assert(pubkey_eq(&route[0]->dst->id, &c));
assert(pubkey_eq(&first->nodes[0]->id, &a)
|| pubkey_eq(&first->nodes[1]->id, &a));
assert(pubkey_eq(&first->nodes[0]->id, &b)
|| pubkey_eq(&first->nodes[1]->id, &b));
assert(pubkey_eq(&route[0]->nodes[0]->id, &b)
|| pubkey_eq(&route[0]->nodes[1]->id, &b));
assert(pubkey_eq(&route[0]->nodes[0]->id, &c)
|| pubkey_eq(&route[0]->nodes[1]->id, &c));
tal_free(ctx);
secp256k1_context_destroy(secp256k1_ctx);

44
gossipd/test/run-find_route.c
View File

@ -130,16 +130,30 @@ static struct node_connection *get_connection(struct routing_state *rstate,
return &c->connections[idx];
}
static bool channel_is_between(const struct routing_channel *chan,
const struct pubkey *a, const struct pubkey *b)
{
if (pubkey_eq(&chan->nodes[0]->id, a)
&& pubkey_eq(&chan->nodes[1]->id, b))
return true;
if (pubkey_eq(&chan->nodes[0]->id, b)
&& pubkey_eq(&chan->nodes[1]->id, a))
return true;
return false;
}
int main(void)
{
static const struct bitcoin_blkid zerohash;
const tal_t *ctx = trc = tal_tmpctx(NULL);
struct node_connection *nc;
struct routing_state *rstate;
struct pubkey a, b, c, d;
struct privkey tmp;
u64 fee;
struct node_connection **route;
struct routing_channel **route;
struct routing_channel *first;
const double riskfactor = 1.0 / BLOCKS_PER_YEAR / 10000;
secp256k1_ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY
@ -158,8 +172,8 @@ int main(void)
/* A<->B */
add_connection(rstate, &a, &b, 1, 1, 1);
nc = find_route(ctx, rstate, &a, &b, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &b, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 0);
assert(fee == 0);
@ -173,8 +187,8 @@ int main(void)
status_trace("C = %s", type_to_string(trc, struct pubkey, &c));
add_connection(rstate, &b, &c, 1, 1, 1);
nc = find_route(ctx, rstate, &a, &c, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &c, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 1);
assert(fee == 1);
@ -188,25 +202,25 @@ int main(void)
add_connection(rstate, &d, &c, 0, 2, 1);
/* Will go via D for small amounts. */
nc = find_route(ctx, rstate, &a, &c, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &c, 1000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 1);
assert(pubkey_eq(&route[0]->src->id, &d));
assert(channel_is_between(route[0], &d, &c));
assert(fee == 0);
/* Will go via B for large amounts. */
nc = find_route(ctx, rstate, &a, &c, 3000000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &c, 3000000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 1);
assert(pubkey_eq(&route[0]->src->id, &b));
assert(channel_is_between(route[0], &b, &c));
assert(fee == 1 + 3);
/* Make B->C inactive, force it back via D */
get_connection(rstate, &b, &c)->active = false;
nc = find_route(ctx, rstate, &a, &c, 3000000, riskfactor, 0.0, NULL, &fee, &route);
assert(nc);
first = find_route(ctx, rstate, &a, &c, 3000000, riskfactor, 0.0, NULL, &fee, &route);
assert(first);
assert(tal_count(route) == 1);
assert(pubkey_eq(&route[0]->src->id, &d));
assert(channel_is_between(route[0], &d, &c));
assert(fee == 0 + 6);
tal_free(ctx);