core-lightning/daemon/pay.c
Rusty Russell 2610799bda pay: split into getroute and sendpay
This is less convenient to use, but makes far more sense for a real
user (like a wallet).  It can ask about the route, then decide whether
to use it or not.

This will make even more sense once we add a parameter to control how
long we let the HTLC be delayed for, so a client can query for high,
medium and low tolerances and compare results.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-08-31 16:06:08 +09:30

371 lines
9.5 KiB
C

#include "chaintopology.h"
#include "failure.h"
#include "jsonrpc.h"
#include "lightningd.h"
#include "log.h"
#include "onion.h"
#include "pay.h"
#include "peer.h"
#include "routing.h"
#include <ccan/str/hex/hex.h>
#include <ccan/structeq/structeq.h>
#include <inttypes.h>
/* Outstanding "pay" commands. */
struct pay_command {
struct list_node list;
struct sha256 rhash;
u64 msatoshis;
struct pubkey id;
/* Set if this is in progress. */
struct htlc *htlc;
/* Preimage if this succeeded. */
struct rval *rval;
struct command *cmd;
};
static void json_pay_success(struct command *cmd, const struct rval *rval)
{
struct json_result *response;
response = new_json_result(cmd);
json_object_start(response, NULL);
json_add_hex(response, "preimage", rval, sizeof(*rval));
json_object_end(response);
command_success(cmd, response);
}
static void handle_json(struct command *cmd, const struct htlc *htlc)
{
FailInfo *f;
struct pubkey id;
const char *idstr = "INVALID";
if (htlc->r) {
json_pay_success(cmd, htlc->r);
return;
}
f = failinfo_unwrap(cmd, htlc->fail, tal_count(htlc->fail));
if (!f) {
command_fail(cmd, "failed (bad message)");
return;
}
if (proto_to_pubkey(cmd->dstate->secpctx, f->id, &id))
idstr = pubkey_to_hexstr(cmd, cmd->dstate->secpctx, &id);
command_fail(cmd,
"failed: error code %u node %s reason %s",
f->error_code, idstr, f->reason ? f->reason : "unknown");
}
void complete_pay_command(struct lightningd_state *dstate,
const struct htlc *htlc)
{
struct pay_command *i;
list_for_each(&dstate->pay_commands, i, list) {
if (i->htlc == htlc) {
if (htlc->r)
i->rval = tal_dup(i, struct rval, htlc->r);
i->htlc = NULL;
/* Can be NULL if JSON RPC goes away. */
if (i->cmd)
handle_json(i->cmd, htlc);
return;
}
}
/* Can happen if RPC connection goes away. */
log_unusual(dstate->base_log, "No command for HTLC %"PRIu64" %s",
htlc->id, htlc->r ? "fulfill" : "fail");
}
/* When JSON RPC goes away, cmd is freed: detach from any running paycommand */
static void remove_cmd_from_pc(struct command *cmd)
{
struct pay_command *pc;
list_for_each(&cmd->dstate->pay_commands, pc, list) {
if (pc->cmd == cmd) {
pc->cmd = NULL;
return;
}
}
/* We can reach here, in the case where another pay command
* re-uses the pc->cmd before we get around to cleaning up. */
}
static struct pay_command *find_pay_command(struct lightningd_state *dstate,
const struct sha256 *rhash)
{
struct pay_command *pc;
list_for_each(&dstate->pay_commands, pc, list) {
if (structeq(rhash, &pc->rhash))
return pc;
}
return NULL;
}
static void json_add_route(struct json_result *response,
secp256k1_context *secpctx,
const struct pubkey *id,
u64 amount, unsigned int delay)
{
json_object_start(response, NULL);
json_add_pubkey(response, secpctx, "id", id);
json_add_u64(response, "msatoshis", amount);
json_add_num(response, "delay", delay);
json_object_end(response);
}
static void json_getroute(struct command *cmd,
const char *buffer, const jsmntok_t *params)
{
struct pubkey id;
jsmntok_t *idtok, *msatoshistok;
struct json_result *response;
int i;
u64 msatoshis;
s64 fee;
struct node_connection **route;
struct peer *peer;
u64 *amounts, total_amount;
unsigned int total_delay, *delays;
if (!json_get_params(buffer, params,
"id", &idtok,
"msatoshis", &msatoshistok,
NULL)) {
command_fail(cmd, "Need id and msatoshis");
return;
}
if (!pubkey_from_hexstr(cmd->dstate->secpctx,
buffer + idtok->start,
idtok->end - idtok->start, &id)) {
command_fail(cmd, "Invalid id");
return;
}
if (!json_tok_u64(buffer, msatoshistok, &msatoshis)) {
command_fail(cmd, "'%.*s' is not a valid number",
(int)(msatoshistok->end - msatoshistok->start),
buffer + msatoshistok->start);
return;
}
peer = find_route(cmd->dstate, &id, msatoshis, &fee, &route);
if (!peer) {
command_fail(cmd, "no route found");
return;
}
/* Fees, delays need to be calculated backwards along route. */
amounts = tal_arr(cmd, u64, tal_count(route)+1);
delays = tal_arr(cmd, unsigned int, tal_count(route)+1);
total_amount = msatoshis;
total_delay = 0;
for (i = tal_count(route) - 1; i >= 0; i--) {
amounts[i+1] = total_amount;
total_amount += connection_fee(route[i], total_amount);
total_delay += route[i]->delay;
if (total_delay < route[i]->min_blocks)
total_delay = route[i]->min_blocks;
delays[i+1] = total_delay;
}
/* We don't charge ourselves any fees. */
amounts[0] = total_amount;
/* We do require delay though. */
total_delay += peer->nc->delay;
if (total_delay < peer->nc->min_blocks)
total_delay = peer->nc->min_blocks;
delays[0] = total_delay;
response = new_json_result(cmd);
json_object_start(response, NULL);
json_array_start(response, "route");
json_add_route(response, cmd->dstate->secpctx,
peer->id, amounts[0], delays[0]);
for (i = 0; i < tal_count(route); i++)
json_add_route(response, cmd->dstate->secpctx,
&route[i]->dst->id, amounts[i+1], delays[i+1]);
json_array_end(response);
json_object_end(response);
command_success(cmd, response);
}
const struct json_command getroute_command = {
"getroute",
json_getroute,
"Return route for {msatoshis} to {id}",
"Returns a {route} array of {id} {msatoshis} {delay}: msatoshis and delay (in blocks) is cumulative."
};
static void json_sendpay(struct command *cmd,
const char *buffer, const jsmntok_t *params)
{
struct pubkey *ids;
u64 *amounts;
jsmntok_t *routetok, *rhashtok;
const jsmntok_t *t, *end;
unsigned int delay;
size_t n_hops;
struct sha256 rhash;
struct peer *peer;
struct pay_command *pc;
const u8 *onion;
enum fail_error error_code;
const char *err;
if (!json_get_params(buffer, params,
"route", &routetok,
"rhash", &rhashtok,
NULL)) {
command_fail(cmd, "Need route and rhash");
return;
}
if (!hex_decode(buffer + rhashtok->start,
rhashtok->end - rhashtok->start,
&rhash, sizeof(rhash))) {
command_fail(cmd, "'%.*s' is not a valid sha256 hash",
(int)(rhashtok->end - rhashtok->start),
buffer + rhashtok->start);
return;
}
if (routetok->type != JSMN_ARRAY) {
command_fail(cmd, "'%.*s' is not an array",
(int)(routetok->end - routetok->start),
buffer + routetok->start);
return;
}
end = json_next(routetok);
n_hops = 0;
amounts = tal_arr(cmd, u64, n_hops);
ids = tal_arr(cmd, struct pubkey, n_hops);
for (t = routetok + 1; t < end; t = json_next(t)) {
const jsmntok_t *amttok, *idtok, *delaytok;
if (t->type != JSMN_OBJECT) {
command_fail(cmd, "route %zu '%.*s' is not an object",
n_hops,
(int)(t->end - t->start),
buffer + t->start);
return;
}
amttok = json_get_member(buffer, t, "msatoshis");
idtok = json_get_member(buffer, t, "id");
delaytok = json_get_member(buffer, t, "delay");
if (!amttok || !idtok || !delaytok) {
command_fail(cmd, "route %zu needs msatoshis/id/delay",
n_hops);
return;
}
tal_resize(&amounts, n_hops+1);
if (!json_tok_u64(buffer, amttok, &amounts[n_hops])) {
command_fail(cmd, "route %zu invalid msatoshis", n_hops);
return;
}
tal_resize(&ids, n_hops+1);
if (!pubkey_from_hexstr(cmd->dstate->secpctx,
buffer + idtok->start,
idtok->end - idtok->start,
&ids[n_hops])) {
command_fail(cmd, "route %zu invalid id", n_hops);
return;
}
/* Only need first delay. */
if (n_hops == 0 && !json_tok_number(buffer, delaytok, &delay)) {
command_fail(cmd, "route %zu invalid delay", n_hops);
return;
}
n_hops++;
}
if (n_hops == 0) {
command_fail(cmd, "Empty route");
return;
}
pc = find_pay_command(cmd->dstate, &rhash);
if (pc) {
log_debug(cmd->dstate->base_log, "json_sendpay: found previous");
if (pc->htlc) {
log_add(cmd->dstate->base_log, "... still in progress");
command_fail(cmd, "still in progress");
return;
}
if (pc->rval) {
log_add(cmd->dstate->base_log, "... succeeded");
/* Must match successful payment parameters. */
if (pc->msatoshis != amounts[n_hops-1]) {
command_fail(cmd,
"already succeeded with amount %"
PRIu64, pc->msatoshis);
return;
}
if (!structeq(&pc->id, &ids[n_hops-1])) {
char *previd;
previd = pubkey_to_hexstr(cmd,
cmd->dstate->secpctx,
&pc->id);
command_fail(cmd,
"already succeeded to %s",
previd);
return;
}
json_pay_success(cmd, pc->rval);
return;
}
log_add(cmd->dstate->base_log, "... retrying");
}
peer = find_peer(cmd->dstate, &ids[0]);
if (!peer) {
command_fail(cmd, "no connection to first peer found");
return;
}
/* Onion will carry us from first peer onwards. */
onion = onion_create(cmd, cmd->dstate->secpctx, ids+1, amounts+1,
n_hops-1);
if (!pc)
pc = tal(cmd->dstate, struct pay_command);
pc->cmd = cmd;
pc->rhash = rhash;
pc->rval = NULL;
pc->id = ids[n_hops-1];
pc->msatoshis = amounts[n_hops-1];
/* Expiry for HTLCs is absolute. And add one to give some margin. */
err = command_htlc_add(peer, amounts[0],
delay + get_block_height(cmd->dstate) + 1,
&rhash, NULL,
onion, &error_code, &pc->htlc);
if (err) {
command_fail(cmd, "could not add htlc: %u: %s", error_code, err);
return;
}
/* Wait until we get response. */
list_add_tail(&cmd->dstate->pay_commands, &pc->list);
tal_add_destructor(cmd, remove_cmd_from_pc);
}
const struct json_command sendpay_command = {
"sendpay",
json_sendpay,
"Send along {route} in return for preimage of {rhash}",
"Returns the {preimage} on success"
};