core-lightning/daemon/routing.c
Christian Decker 754616c45a routing: Fix for single hop routes segfaulting.
The first hop is being stripped from computed routes, however the
first channel of the route is being used to get our peer address. This
results in segfaults if the route is just one hop, i.e., has no first
channel to get the peer's address from. Fixed by simply using an
existing pointer to our peer.
2016-08-26 15:39:35 +09:30

437 lines
11 KiB
C

#include "jsonrpc.h"
#include "lightningd.h"
#include "log.h"
#include "overflows.h"
#include "peer.h"
#include "pseudorand.h"
#include "routing.h"
#include <ccan/array_size/array_size.h>
#include <ccan/crypto/siphash24/siphash24.h>
#include <ccan/htable/htable_type.h>
#include <ccan/structeq/structeq.h>
#include <inttypes.h>
static const secp256k1_pubkey *keyof_node(const struct node *n)
{
return &n->id.pubkey;
}
static size_t hash_key(const secp256k1_pubkey *key)
{
return siphash24(siphash_seed(), key, sizeof(key));
}
static bool node_eq(const struct node *n, const secp256k1_pubkey *key)
{
return structeq(&n->id.pubkey, key);
}
HTABLE_DEFINE_TYPE(struct node, keyof_node, hash_key, node_eq, node_map);
struct node_map *empty_node_map(struct lightningd_state *dstate)
{
struct node_map *map = tal(dstate, struct node_map);
node_map_init(map);
return map;
}
struct node *get_node(struct lightningd_state *dstate,
const struct pubkey *id)
{
return node_map_get(dstate->nodes, &id->pubkey);
}
static void destroy_node(struct node *node)
{
/* These remove themselves from the array. */
while (tal_count(node->in))
tal_free(node->in[0]);
while (tal_count(node->out))
tal_free(node->out[0]);
}
struct node *new_node(struct lightningd_state *dstate,
const struct pubkey *id)
{
struct node *n;
assert(!get_node(dstate, id));
n = tal(dstate, struct node);
n->id = *id;
n->in = tal_arr(n, struct node_connection *, 0);
n->out = tal_arr(n, struct node_connection *, 0);
node_map_add(dstate->nodes, n);
tal_add_destructor(n, destroy_node);
return n;
}
static bool remove_conn_from_array(struct node_connection ***conns,
struct node_connection *nc)
{
size_t i, n;
n = tal_count(*conns);
for (i = 0; i < n; i++) {
if ((*conns)[i] != nc)
continue;
n--;
memmove(*conns + i, *conns + i + 1, sizeof(**conns) * (n - i));
tal_resize(conns, n);
return true;
}
return false;
}
static void destroy_connection(struct node_connection *nc)
{
if (!remove_conn_from_array(&nc->dst->in, nc)
|| !remove_conn_from_array(&nc->src->out, nc))
fatal("Connection not found in array?!");
}
static struct node_connection *
get_or_make_connection(struct lightningd_state *dstate,
const struct pubkey *from_id,
const struct pubkey *to_id)
{
size_t i, n;
struct node *from, *to;
struct node_connection *nc;
from = get_node(dstate, from_id);
if (!from)
from = new_node(dstate, from_id);
to = get_node(dstate, to_id);
if (!to)
to = new_node(dstate, to_id);
n = tal_count(to->in);
for (i = 0; i < n; i++) {
if (to->in[i]->src == from) {
log_debug_struct(dstate->base_log,
"Updating existing route from %s",
struct pubkey, &from->id);
log_add_struct(dstate->base_log, " to %s",
struct pubkey, &to->id);
return to->in[i];
}
}
log_debug_struct(dstate->base_log, "Creating new route from %s",
struct pubkey, &from->id);
log_add_struct(dstate->base_log, " to %s", struct pubkey, &to->id);
nc = tal(dstate, struct node_connection);
nc->src = from;
nc->dst = to;
log_add(dstate->base_log, " = %p (%p->%p)", nc, from, to);
/* Hook it into in/out arrays. */
i = tal_count(to->in);
tal_resize(&to->in, i+1);
to->in[i] = nc;
i = tal_count(from->out);
tal_resize(&from->out, i+1);
from->out[i] = nc;
tal_add_destructor(nc, destroy_connection);
return nc;
}
/* Updates existing route if required. */
struct node_connection *add_connection(struct lightningd_state *dstate,
const struct pubkey *from,
const struct pubkey *to,
u32 base_fee, s32 proportional_fee,
u32 delay, u32 min_blocks)
{
struct node_connection *c = get_or_make_connection(dstate, from, to);
c->base_fee = base_fee;
c->proportional_fee = proportional_fee;
c->delay = delay;
c->min_blocks = min_blocks;
return c;
}
/* Too big to reach, but don't overflow if added. */
#define INFINITE 0x3FFFFFFFFFFFFFFFULL
static void clear_bfg(struct node_map *nodes)
{
struct node *n;
struct node_map_iter it;
for (n = node_map_first(nodes, &it); n; n = node_map_next(nodes, &it)) {
size_t i;
for (i = 0; i < ARRAY_SIZE(n->bfg); i++)
n->bfg[i].total = INFINITE;
}
}
s64 connection_fee(const struct node_connection *c, u64 msatoshi)
{
s64 fee;
if (mul_overflows_s64(c->proportional_fee, msatoshi))
return INFINITE;
fee = (c->proportional_fee * msatoshi) / 1000000;
/* This can't overflow: c->base_fee is a u32 */
return c->base_fee + fee;
}
/* 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, size_t edgenum)
{
struct node_connection *c = node->in[edgenum];
size_t h;
assert(c->dst == node);
for (h = 0; h < ROUTING_MAX_HOPS; h++) {
/* FIXME: Bias towards smaller expiry values. */
/* FIXME: Bias against smaller channels. */
s64 fee = connection_fee(c, node->bfg[h].total);
if (node->bfg[h].total + fee < c->src->bfg[h+1].total) {
c->src->bfg[h+1].total = node->bfg[h].total + fee;
c->src->bfg[h+1].prev = c;
}
}
}
struct peer *find_route(struct lightningd_state *dstate,
const struct pubkey *to,
u64 msatoshi, s64 *fee,
struct node_connection ***route)
{
struct node *n, *src, *dst;
struct node_map_iter it;
struct peer *first;
int runs, i, best;
/* Note: we map backwards, since we know the amount of satoshi we want
* at the end, and need to derive how much we need to send. */
dst = get_node(dstate, &dstate->id);
src = get_node(dstate, to);
if (!src) {
log_info_struct(dstate->base_log, "find_route: cannot find %s",
struct pubkey, to);
return NULL;
}
/* Reset all the information. */
clear_bfg(dstate->nodes);
/* Bellman-Ford-Gibson: like Bellman-Ford, but keep values for
* every path length. */
src->bfg[0].total = msatoshi;
for (runs = 0; runs < ROUTING_MAX_HOPS; runs++) {
log_debug(dstate->base_log, "Run %i", runs);
/* Run through every edge. */
for (n = node_map_first(dstate->nodes, &it);
n;
n = node_map_next(dstate->nodes, &it)) {
size_t num_edges = tal_count(n->in);
for (i = 0; i < num_edges; i++) {
bfg_one_edge(n, i);
log_debug(dstate->base_log, "We seek %p->%p, this is %p -> %p",
dst, src, n->in[i]->src, n->in[i]->dst);
log_debug_struct(dstate->base_log,
"Checking from %s",
struct pubkey,
&n->in[i]->src->id);
log_add_struct(dstate->base_log,
" to %s",
struct pubkey,
&n->in[i]->dst->id);
}
}
}
best = 0;
for (i = 1; i <= ROUTING_MAX_HOPS; i++) {
if (dst->bfg[i].total < dst->bfg[best].total)
best = i;
}
/* No route? */
if (dst->bfg[best].total >= INFINITE) {
log_info_struct(dstate->base_log, "find_route: No route to %s",
struct pubkey, to);
return NULL;
}
/* 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. */
dst = dst->bfg[best].prev->dst;
best--;
*fee = dst->bfg[best].total - msatoshi;
*route = tal_arr(dstate, struct node_connection *, best);
for (i = 0, n = dst;
i < best;
n = n->bfg[best-i].prev->dst, i++) {
(*route)[i] = n->bfg[best-i].prev;
}
assert(n == src);
/* We should only add routes if we have a peer. */
first = find_peer(dstate, &dst->id);
if (!first) {
log_broken_struct(dstate->base_log, "No peer %s?",
struct pubkey, &(*route)[0]->src->id);
return NULL;
}
msatoshi += *fee;
log_info(dstate->base_log, "find_route:");
log_add_struct(dstate->base_log, "via %s", struct pubkey, first->id);
for (i = 0; i < best; i++) {
log_add_struct(dstate->base_log, " %s",
struct pubkey, &(*route)[i]->dst->id);
log_add(dstate->base_log, "(%i+%i=%"PRIu64")",
(*route)[i]->base_fee,
(*route)[i]->proportional_fee,
connection_fee((*route)[i], msatoshi));
msatoshi -= connection_fee((*route)[i], msatoshi);
}
log_add(dstate->base_log, "=%"PRIi64"(%+"PRIi64")",
(*route)[best-1]->dst->bfg[best-1].total, *fee);
return first;
}
static bool get_slash_u32(const char **arg, u32 *v)
{
size_t len;
char *endp;
if (**arg != '/')
return false;
(*arg)++;
len = strcspn(*arg, "/");
*v = strtoul(*arg, &endp, 10);
(*arg) += len;
return (endp == *arg);
}
/* srcid/dstid/base/var/delay/minblocks */
char *opt_add_route(const char *arg, struct lightningd_state *dstate)
{
size_t len;
struct pubkey src, dst;
u32 base, var, delay, minblocks;
len = strcspn(arg, "/");
if (!pubkey_from_hexstr(dstate->secpctx, arg, len, &src))
return "Bad src pubkey";
arg += len + 1;
len = strcspn(arg, "/");
if (!pubkey_from_hexstr(dstate->secpctx, arg, len, &dst))
return "Bad dst pubkey";
arg += len;
if (!get_slash_u32(&arg, &base)
|| !get_slash_u32(&arg, &var)
|| !get_slash_u32(&arg, &delay)
|| !get_slash_u32(&arg, &minblocks))
return "Bad base/var/delay/minblocks";
if (*arg)
return "Data after minblocks";
add_connection(dstate, &src, &dst, base, var, delay, minblocks);
return NULL;
}
static void json_add_route(struct command *cmd,
const char *buffer, const jsmntok_t *params)
{
jsmntok_t *srctok, *dsttok, *basetok, *vartok, *delaytok, *minblockstok;
struct pubkey src, dst;
u32 base, var, delay, minblocks;
if (!json_get_params(buffer, params,
"src", &srctok,
"dst", &dsttok,
"base", &basetok,
"var", &vartok,
"delay", &delaytok,
"minblocks", &minblockstok,
NULL)) {
command_fail(cmd, "Need src, dst, base, var, delay & minblocks");
return;
}
if (!pubkey_from_hexstr(cmd->dstate->secpctx,
buffer + srctok->start,
srctok->end - srctok->start, &src)) {
command_fail(cmd, "src %.*s not valid",
srctok->end - srctok->start,
buffer + srctok->start);
return;
}
if (!pubkey_from_hexstr(cmd->dstate->secpctx,
buffer + dsttok->start,
dsttok->end - dsttok->start, &dst)) {
command_fail(cmd, "dst %.*s not valid",
dsttok->end - dsttok->start,
buffer + dsttok->start);
return;
}
if (!json_tok_number(buffer, basetok, &base)
|| !json_tok_number(buffer, vartok, &var)
|| !json_tok_number(buffer, delaytok, &delay)
|| !json_tok_number(buffer, minblockstok, &minblocks)) {
command_fail(cmd,
"base, var, delay and minblocks must be numbers");
return;
}
add_connection(cmd->dstate, &src, &dst, base, var, delay, minblocks);
command_success(cmd, null_response(cmd));
}
const struct json_command add_route_command = {
"add-route",
json_add_route,
"Add route from {src} to {dst}, {base} rate in msatoshi, {var} rate in msatoshi, {delay} blocks delay and {minblocks} minimum timeout",
"Returns an empty result on success"
};
static void json_routefail(struct command *cmd,
const char *buffer, const jsmntok_t *params)
{
jsmntok_t *enabletok;
bool enable;
if (!json_get_params(buffer, params,
"enable", &enabletok,
NULL)) {
command_fail(cmd, "Need enable");
return;
}
if (!json_tok_bool(buffer, enabletok, &enable)) {
command_fail(cmd, "enable must be true or false");
return;
}
log_debug(cmd->dstate->base_log, "dev-routefail: routefail %s",
enable ? "enabled" : "disabled");
cmd->dstate->dev_never_routefail = !enable;
command_success(cmd, null_response(cmd));
}
const struct json_command routefail_command = {
"dev-routefail",
json_routefail,
"FAIL htlcs that we can't route if {enable}",
"Returns an empty result on success"
};