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channel.c
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/* Main channel operation daemon: runs from funding_locked to shutdown_complete.
*
* We're fairly synchronous: our main loop looks for gossip, master or
* peer requests and services them synchronously.
*
* The exceptions are:
* 1. When we've asked the master something: in that case, we queue
* non-response packets for later processing while we await the reply.
* 2. We queue and send non-blocking responses to peers: if both peers were
* reading and writing synchronously we could deadlock if we hit buffer
* limits, unlikely as that is.
*/
#include <bitcoin/privkey.h>
#include <bitcoin/script.h>
#include <ccan/cast/cast.h>
#include <ccan/container_of/container_of.h>
#include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
#include <ccan/crypto/shachain/shachain.h>
#include <ccan/err/err.h>
#include <ccan/fdpass/fdpass.h>
#include <ccan/mem/mem.h>
#include <ccan/structeq/structeq.h>
#include <ccan/take/take.h>
#include <ccan/tal/str/str.h>
#include <ccan/time/time.h>
#include <channeld/commit_tx.h>
#include <channeld/full_channel.h>
#include <channeld/gen_channel_wire.h>
#include <common/crypto_sync.h>
#include <common/derive_basepoints.h>
#include <common/dev_disconnect.h>
#include <common/htlc_tx.h>
#include <common/io_debug.h>
#include <common/key_derive.h>
#include <common/msg_queue.h>
#include <common/peer_failed.h>
#include <common/ping.h>
#include <common/sphinx.h>
#include <common/status.h>
#include <common/subdaemon.h>
#include <common/timeout.h>
#include <common/type_to_string.h>
#include <common/version.h>
#include <common/wire_error.h>
#include <errno.h>
#include <fcntl.h>
#include <gossipd/gen_gossip_wire.h>
#include <gossipd/routing.h>
#include <hsmd/gen_hsm_client_wire.h>
#include <inttypes.h>
#include <secp256k1.h>
#include <stdio.h>
#include <wire/gen_onion_wire.h>
#include <wire/peer_wire.h>
#include <wire/wire.h>
#include <wire/wire_io.h>
#include <wire/wire_sync.h>
/* stdin == requests, 3 == peer, 4 = gossip, 5 = HSM */
#define MASTER_FD STDIN_FILENO
#define PEER_FD 3
#define GOSSIP_FD 4
#define HSM_FD 5
struct commit_sigs {
struct peer *peer;
secp256k1_ecdsa_signature commit_sig;
secp256k1_ecdsa_signature *htlc_sigs;
};
struct peer {
struct crypto_state cs;
struct channel_config conf[NUM_SIDES];
bool funding_locked[NUM_SIDES];
u64 next_index[NUM_SIDES];
/* Tolerable amounts for feerate (only relevant for fundee). */
u32 feerate_min, feerate_max;
/* Remote's current per-commit point. */
struct pubkey remote_per_commit;
/* Remotes's last per-commitment point: we keep this to check
* revoke_and_ack's `per_commitment_secret` is correct. */
struct pubkey old_remote_per_commit;
/* Their sig for current commit. */
secp256k1_ecdsa_signature their_commit_sig;
/* Secret keys and basepoint secrets. */
struct secrets our_secrets;
/* Our shaseed for generating per-commitment-secrets. */
struct sha256 shaseed;
/* BOLT #2:
*
* A sending node MUST set `id` to 0 for the first HTLC it offers, and
* increase the value by 1 for each successive offer.
*/
u64 htlc_id;
struct bitcoin_blkid chain_hash;
struct channel_id channel_id;
struct channel *channel;
/* Pending msgs to send (not encrypted) */
struct msg_queue peer_out;
/* Current msg to send, and offset (encrypted) */
const u8 *peer_outmsg;
size_t peer_outoff;
/* Messages from master / gossipd: we queue them since we
* might be waiting for a specific reply. */
struct msg_queue from_master, from_gossipd;
struct timers timers;
struct oneshot *commit_timer;
u32 commit_msec;
/* Don't accept a pong we didn't ping for. */
size_t num_pings_outstanding;
/* The feerate we want. */
u32 desired_feerate;
/* Announcement related information */
struct pubkey node_ids[NUM_SIDES];
struct short_channel_id short_channel_ids[NUM_SIDES];
secp256k1_ecdsa_signature announcement_node_sigs[NUM_SIDES];
secp256k1_ecdsa_signature announcement_bitcoin_sigs[NUM_SIDES];
bool have_sigs[NUM_SIDES];
/* Which direction of the channel do we control? */
u16 channel_direction;
/* CLTV delta to announce to peers */
u16 cltv_delta;
u32 fee_base;
u32 fee_per_satoshi;
/* We save calculated commit sigs while waiting for master approval */
struct commit_sigs *next_commit_sigs;
/* If master told us to shut down, this contains scriptpubkey until
* we're ready to send it. */
u8 *unsent_shutdown_scriptpubkey;
bool shutdown_sent[NUM_SIDES];
/* Information used for reestablishment. */
bool last_was_revoke;
struct changed_htlc *last_sent_commit;
u64 revocations_received;
u8 channel_flags;
bool announce_depth_reached;
/* Where we got up to in gossip broadcasts. */
u64 gossip_index;
/* Make sure timestamps move forward. */
u32 last_update_timestamp;
};
static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer);
static void start_commit_timer(struct peer *peer);
/* Returns a pointer to the new end */
static void *tal_arr_append_(void **p, size_t size)
{
size_t n = tal_len(*p) / size;
tal_resize_(p, size, n+1, false);
return (char *)(*p) + n * size;
}
#define tal_arr_append(p) tal_arr_append_((void **)(p), sizeof(**(p)))
static void do_peer_write(struct peer *peer)
{
int r;
size_t len = tal_len(peer->peer_outmsg);
r = write(PEER_FD, peer->peer_outmsg + peer->peer_outoff,
len - peer->peer_outoff);
if (r < 0)
status_failed(STATUS_FAIL_PEER_IO,
"Peer write failed: %s", strerror(errno));
peer->peer_outoff += r;
if (peer->peer_outoff == len)
peer->peer_outmsg = tal_free(peer->peer_outmsg);
}
static bool peer_write_pending(struct peer *peer)
{
const u8 *msg;
if (peer->peer_outmsg)
return true;
msg = msg_dequeue(&peer->peer_out);
if (!msg)
return false;
status_trace("peer_out %s", wire_type_name(fromwire_peektype(msg)));
peer->peer_outmsg = cryptomsg_encrypt_msg(peer, &peer->cs, take(msg));
peer->peer_outoff = 0;
return true;
}
/* Synchronous flush of all pending packets. */
static void flush_peer_out(struct peer *peer)
{
while (peer_write_pending(peer))
do_peer_write(peer);
}
static void enqueue_peer_msg(struct peer *peer, const u8 *msg TAKES)
{
#if DEVELOPER
enum dev_disconnect d = dev_disconnect(fromwire_peektype(msg));
/* We want to effect this exact packet, so flush any pending. */
if (d != DEV_DISCONNECT_NORMAL)
flush_peer_out(peer);
switch (d) {
case DEV_DISCONNECT_BEFORE:
/* Fail immediately. */
dev_sabotage_fd(PEER_FD);
msg_enqueue(&peer->peer_out, msg);
flush_peer_out(peer);
/* Should not return */
abort();
case DEV_DISCONNECT_DROPPKT:
tal_free(msg);
/* Fail next time we try to do something. */
dev_sabotage_fd(PEER_FD);
return;
case DEV_DISCONNECT_AFTER:
msg_enqueue(&peer->peer_out, msg);
flush_peer_out(peer);
dev_sabotage_fd(PEER_FD);
return;
case DEV_DISCONNECT_BLACKHOLE:
msg_enqueue(&peer->peer_out, msg);
dev_blackhole_fd(PEER_FD);
return;
case DEV_DISCONNECT_NORMAL:
break;
}
#endif
msg_enqueue(&peer->peer_out, msg);
}
static void gossip_in(struct peer *peer, const u8 *msg)
{
u8 *gossip;
u16 type;
if (!fromwire_gossip_send_gossip(msg, msg, NULL,
&peer->gossip_index, &gossip))
status_failed(STATUS_FAIL_GOSSIP_IO,
"Got bad message from gossipd: %s",
tal_hex(msg, msg));
type = fromwire_peektype(gossip);
if (type == WIRE_CHANNEL_ANNOUNCEMENT || type == WIRE_CHANNEL_UPDATE ||
type == WIRE_NODE_ANNOUNCEMENT)
enqueue_peer_msg(peer, gossip);
else
status_failed(STATUS_FAIL_GOSSIP_IO,
"Got bad message type %s from gossipd: %s",
wire_type_name(type), tal_hex(msg, msg));
}
/* Send a temporary `channel_announcement` and `channel_update`. These
* are unsigned and mainly used to tell gossip about the channel
* before we have reached the `announcement_depth`, not being signed
* means they will not be relayed, but we can already rely on them for
* our own outgoing payments */
static void send_temporary_announcement(struct peer *peer)
{
tal_t *tmpctx;
u8 *msg;
/* If we are supposed to send a real announcement, don't do a
* dummy one here, hence the check for announce_depth. */
if (peer->announce_depth_reached || !peer->funding_locked[LOCAL] ||
!peer->funding_locked[REMOTE])
return;
tmpctx = tal_tmpctx(peer);
msg = towire_gossip_local_add_channel(
tmpctx, &peer->short_channel_ids[LOCAL], &peer->chain_hash,
&peer->node_ids[REMOTE], 0 /* flags */, peer->cltv_delta,
peer->conf[REMOTE].htlc_minimum_msat, peer->fee_base,
peer->fee_per_satoshi);
wire_sync_write(GOSSIP_FD, take(msg));
tal_free(tmpctx);
}
static void send_announcement_signatures(struct peer *peer)
{
/* First 2 + 256 byte are the signatures and msg type, skip them */
size_t offset = 258;
const tal_t *tmpctx;
struct sha256_double hash;
u8 *msg, *ca, *req;
/* BOLT #7:
*
* If sent, `announcement_signatures` messages MUST NOT be sent until
* `funding_locked` has been sent and the funding transaction has
* at least 6 confirmations.
*/
/* Actually defer a bit further until both ends have signaled */
if (!peer->announce_depth_reached || !peer->funding_locked[LOCAL] ||
!peer->funding_locked[REMOTE])
return;
tmpctx = tal_tmpctx(peer);
status_trace("Exchanging announcement signatures.");
ca = create_channel_announcement(tmpctx, peer);
req = towire_hsm_cannouncement_sig_req(
tmpctx, &peer->channel->funding_pubkey[LOCAL], ca);
if (!wire_sync_write(HSM_FD, req))
status_failed(STATUS_FAIL_HSM_IO,
"Writing cannouncement_sig_req: %s",
strerror(errno));
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg || !fromwire_hsm_cannouncement_sig_reply(msg, NULL,
&peer->announcement_node_sigs[LOCAL]))
status_failed(STATUS_FAIL_HSM_IO,
"Reading cannouncement_sig_resp: %s",
strerror(errno));
/* Double-check that HSM gave a valid signature. */
sha256_double(&hash, ca + offset, tal_len(ca) - offset);
if (!check_signed_hash(&hash, &peer->announcement_node_sigs[LOCAL],
&peer->node_ids[LOCAL])) {
/* It's ok to fail here, the channel announcement is
* unique, unlike the channel update which may have
* been replaced in the meantime. */
status_failed(STATUS_FAIL_HSM_IO,
"HSM returned an invalid signature");
}
/* TODO(cdecker) Move this to the HSM once we store the
* funding_privkey there */
sign_hash(&peer->our_secrets.funding_privkey, &hash,
&peer->announcement_bitcoin_sigs[LOCAL]);
peer->have_sigs[LOCAL] = true;
msg = towire_announcement_signatures(
tmpctx, &peer->channel_id, &peer->short_channel_ids[LOCAL],
&peer->announcement_node_sigs[LOCAL],
&peer->announcement_bitcoin_sigs[LOCAL]);
enqueue_peer_msg(peer, take(msg));
tal_free(tmpctx);
}
static u8 *create_channel_update(const tal_t *ctx,
struct peer *peer, bool disabled)
{
tal_t *tmpctx = tal_tmpctx(ctx);
u32 timestamp = time_now().ts.tv_sec;
u16 flags;
u8 *cupdate, *msg;
/* Identical timestamps will be ignored. */
if (timestamp <= peer->last_update_timestamp)
timestamp = peer->last_update_timestamp + 1;
peer->last_update_timestamp = timestamp;
/* Set the signature to empty so that valgrind doesn't complain */
secp256k1_ecdsa_signature *sig =
talz(tmpctx, secp256k1_ecdsa_signature);
flags = peer->channel_direction | (disabled << 1);
cupdate = towire_channel_update(
tmpctx, sig, &peer->chain_hash,
&peer->short_channel_ids[LOCAL], timestamp, flags,
peer->cltv_delta, peer->conf[REMOTE].htlc_minimum_msat,
peer->fee_base, peer->fee_per_satoshi);
msg = towire_hsm_cupdate_sig_req(tmpctx, cupdate);
if (!wire_sync_write(HSM_FD, msg))
status_failed(STATUS_FAIL_HSM_IO,
"Writing cupdate_sig_req: %s",
strerror(errno));
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg || !fromwire_hsm_cupdate_sig_reply(ctx, msg, NULL, &cupdate))
status_failed(STATUS_FAIL_HSM_IO,
"Reading cupdate_sig_req: %s",
strerror(errno));
tal_free(tmpctx);
return cupdate;
}
/* Tentatively create a channel_announcement, possibly with invalid
* signatures. The signatures need to be collected first, by asking
* the HSM and by exchanging announcement_signature messages. */
static u8 *create_channel_announcement(const tal_t *ctx, struct peer *peer)
{
int first, second;
u8 *cannounce, *features = tal_arr(ctx, u8, 0);
if (peer->channel_direction == 0) {
first = LOCAL;
second = REMOTE;
} else {
first = REMOTE;
second = LOCAL;
}
cannounce = towire_channel_announcement(
ctx, &peer->announcement_node_sigs[first],
&peer->announcement_node_sigs[second],
&peer->announcement_bitcoin_sigs[first],
&peer->announcement_bitcoin_sigs[second],
features,
&peer->chain_hash,
&peer->short_channel_ids[LOCAL], &peer->node_ids[first],
&peer->node_ids[second], &peer->channel->funding_pubkey[first],
&peer->channel->funding_pubkey[second]);
tal_free(features);
return cannounce;
}
static void handle_peer_funding_locked(struct peer *peer, const u8 *msg)
{
struct channel_id chanid;
/* BOLT #2:
*
* On reconnection, a node MUST ignore a redundant `funding_locked` if
* it receives one.
*/
if (peer->funding_locked[REMOTE])
return;
peer->old_remote_per_commit = peer->remote_per_commit;
if (!fromwire_funding_locked(msg, NULL, &chanid,
&peer->remote_per_commit))
peer_failed(PEER_FD, &peer->cs, &peer->channel_id,
"Bad funding_locked %s", tal_hex(msg, msg));
if (!structeq(&chanid, &peer->channel_id))
peer_failed(PEER_FD, &peer->cs, &peer->channel_id,
"Wrong channel id in %s (expected %s)",
tal_hex(trc, msg),
type_to_string(msg, struct channel_id,
&peer->channel_id));
peer->funding_locked[REMOTE] = true;
wire_sync_write(MASTER_FD,
take(towire_channel_got_funding_locked(peer,
&peer->remote_per_commit)));
if (peer->funding_locked[LOCAL]) {
wire_sync_write(MASTER_FD,
take(towire_channel_normal_operation(peer)));
}
/* Send temporary or final announcements */
send_temporary_announcement(peer);
send_announcement_signatures(peer);
}
/* Once we have both, we'd better make sure we agree what they are! */
static void check_short_ids_match(struct peer *peer)
{
assert(peer->have_sigs[LOCAL]);
assert(peer->have_sigs[REMOTE]);
if (!short_channel_id_eq(&peer->short_channel_ids[LOCAL],
&peer->short_channel_ids[REMOTE]))
peer_failed(PEER_FD, &peer->cs, &peer->channel_id,
"We disagree on short_channel_ids:"
" I have %s, you say %s",
type_to_string(peer, struct short_channel_id,
&peer->short_channel_ids[LOCAL]),
type_to_string(peer, struct short_channel_id,
&peer->short_channel_ids[REMOTE]));
}
static void announce_channel(struct peer *peer)
{
tal_t *tmpctx = tal_tmpctx(peer);
u8 *cannounce, *cupdate;
check_short_ids_match(peer);
cannounce = create_channel_announcement(tmpctx, peer);
cupdate = create_channel_update(tmpctx, peer, false);
wire_sync_write(GOSSIP_FD, cannounce);
wire_sync_write(GOSSIP_FD, cupdate);
tal_free(tmpctx);
}
static void handle_peer_announcement_signatures(struct peer *peer, const u8 *msg)
{
struct channel_id chanid;
if (!fromwire_announcement_signatures(msg, NULL,
&chanid,
&peer->short_channel_ids[REMOTE],
&peer->announcement_node_sigs[REMOTE],
&peer->announcement_bitcoin_sigs[REMOTE]))
peer_failed(PEER_FD, &peer->cs, &peer->channel_id,
"Bad announcement_signatures %s",
tal_hex(msg, msg));
/* Make sure we agree on the channel ids */
if (!structeq(&chanid, &peer->channel_id)) {
peer_failed(PEER_FD, &peer->cs, &peer->channel_id,
"Wrong channel_id: expected %s, got %s",
type_to_string(trc, struct channel_id,
&peer->channel_id),
type_to_string(trc, struct channel_id, &chanid));
}
peer->have_sigs[REMOTE] = true;
/* We have the remote sigs, do we have the local ones as well? */
if (peer->funding_locked[LOCAL] && peer->have_sigs[LOCAL])
announce_channel(peer);
}
static bool get_shared_secret(const struct htlc *htlc,
struct secret *shared_secret)
{
tal_t *tmpctx = tal_tmpctx(htlc);
struct pubkey ephemeral;
struct onionpacket *op;
u8 *msg;
/* We unwrap the onion now. */
op = parse_onionpacket(tmpctx, htlc->routing, TOTAL_PACKET_SIZE);
if (!op) {
/* Return an invalid shared secret. */
memset(shared_secret, 0, sizeof(*shared_secret));
tal_free(tmpctx);
return false;
}
/* Because wire takes struct pubkey. */
ephemeral.pubkey = op->ephemeralkey;
msg = towire_hsm_ecdh_req(tmpctx, &ephemeral);
if (!wire_sync_write(HSM_FD, msg))
status_failed(STATUS_FAIL_HSM_IO, "Writing ecdh req");
msg = wire_sync_read(tmpctx, HSM_FD);
/* Gives all-zero shares_secret if it was invalid. */
if (!msg || !fromwire_hsm_ecdh_resp(msg, NULL, shared_secret))
status_failed(STATUS_FAIL_HSM_IO, "Reading ecdh response");
tal_free(tmpctx);
return !memeqzero(shared_secret, sizeof(*shared_secret));
}
static void handle_peer_add_htlc(struct peer *peer, const u8 *msg)
{
struct channel_id channel_id;
u64 id;
u64 amount_msat;
u32 cltv_expiry;
struct sha256 payment_hash;
u8 onion_routing_packet[TOTAL_PACKET_SIZE];
enum channel_add_err add_err;
struct htlc *htlc;
if (!fromwire_update_add_htlc(msg, NULL, &channel_id, &id, &amount_msat,
&payment_hash, &cltv_expiry,
onion_routing_packet))
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"Bad peer_add_htlc %s", tal_hex(msg, msg));
add_err = channel_add_htlc(peer->channel, REMOTE, id, amount_msat,
cltv_expiry, &payment_hash,
onion_routing_packet, &htlc);
if (add_err != CHANNEL_ERR_ADD_OK)
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"Bad peer_add_htlc: %u", add_err);
/* If this is wrong, we don't complain yet; when it's confirmed we'll
* send it to the master which handles all HTLC failures. */
htlc->shared_secret = tal(htlc, struct secret);
get_shared_secret(htlc, htlc->shared_secret);
}
static void handle_peer_feechange(struct peer *peer, const u8 *msg)
{
struct channel_id channel_id;
u32 feerate;
if (!fromwire_update_fee(msg, NULL, &channel_id, &feerate)) {
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"Bad update_fee %s", tal_hex(msg, msg));
}
/* BOLT #2:
*
* A receiving node MUST fail the channel if the sender is not
* responsible for paying the bitcoin fee.
*/
if (peer->channel->funder != REMOTE)
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"update_fee from non-funder?");
status_trace("update_fee %u, range %u-%u",
feerate, peer->feerate_min, peer->feerate_max);
/* BOLT #2:
*
* A receiving node SHOULD fail the channel if the `update_fee` is too
* low for timely processing, or unreasonably large.
*/
if (feerate < peer->feerate_min || feerate > peer->feerate_max)
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"update_fee %u outside range %u-%u",
feerate, peer->feerate_min, peer->feerate_max);
/* BOLT #2:
*
* A receiving node SHOULD fail the channel if the sender cannot
* afford the new fee rate on the receiving node's current commitment
* transaction, but it MAY delay this check until the `update_fee` is
* committed.
*/
if (!channel_update_feerate(peer->channel, feerate))
peer_failed(PEER_FD,
&peer->cs,
&peer->channel_id,
"update_fee %u unaffordable",
feerate);
status_trace("peer updated fee to %u", feerate);
}
static struct changed_htlc *changed_htlc_arr(const tal_t *ctx,
const struct htlc **changed_htlcs)
{
struct changed_htlc *changed;
size_t i;
changed = tal_arr(ctx, struct changed_htlc, tal_count(changed_htlcs));
for (i = 0; i < tal_count(changed_htlcs); i++) {
changed[i].id = changed_htlcs[i]->id;
changed[i].newstate = changed_htlcs[i]->state;
}
return changed;
}
static u8 *sending_commitsig_msg(const tal_t *ctx,
u64 remote_commit_index,
u32 remote_feerate,
const struct htlc **changed_htlcs,
const secp256k1_ecdsa_signature *commit_sig,
const secp256k1_ecdsa_signature *htlc_sigs)
{
const tal_t *tmpctx = tal_tmpctx(ctx);
struct changed_htlc *changed;
u8 *msg;
/* We tell master what (of our) HTLCs peer will now be
* committed to. */
changed = changed_htlc_arr(tmpctx, changed_htlcs);
msg = towire_channel_sending_commitsig(ctx, remote_commit_index,
remote_feerate,
changed, commit_sig, htlc_sigs);
tal_free(tmpctx);
return msg;
}
static bool shutdown_complete(const struct peer *peer)
{
return peer->shutdown_sent[LOCAL]
&& peer->shutdown_sent[REMOTE]
&& !channel_has_htlcs(peer->channel)
/* We could be awaiting revoke-and-ack for a feechange */
&& peer->revocations_received == peer->next_index[REMOTE] - 1;
}
/* BOLT #2:
*
* A node MUST NOT send a `shutdown` if there are updates pending on
* the receiving node's commitment transaction.
*/
/* So we only call this after reestablish or immediately after sending commit */
static void maybe_send_shutdown(struct peer *peer)
{
u8 *msg;
if (!peer->unsent_shutdown_scriptpubkey)
return;
/* Send a disable channel_update so others don't try to route
* over us */
msg = create_channel_update(peer, peer, true);
wire_sync_write(GOSSIP_FD, msg);
enqueue_peer_msg(peer, take(msg));
msg = towire_shutdown(peer, &peer->channel_id,
peer->unsent_shutdown_scriptpubkey);
enqueue_peer_msg(peer, take(msg));
peer->unsent_shutdown_scriptpubkey
= tal_free(peer->unsent_shutdown_scriptpubkey);
peer->shutdown_sent[LOCAL] = true;
}
/* This queues other traffic from the fd until we get reply. */
static u8 *wait_sync_reply(const tal_t *ctx,
const u8 *msg,
int replytype,
int fd,
struct msg_queue *queue,
const char *who)
{
u8 *reply;
status_trace("Sending %s %u", who, fromwire_peektype(msg));
if (!wire_sync_write(fd, msg))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not set sync write to %s: %s",
who, strerror(errno));
status_trace("... , awaiting %u", replytype);
for (;;) {
reply = wire_sync_read(ctx, fd);
if (!reply)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not set sync read from %s: %s",
who, strerror(errno));
if (fromwire_peektype(reply) == replytype) {
status_trace("Got it!");
break;
}
status_trace("Nope, got %u instead", fromwire_peektype(reply));
msg_enqueue(queue, take(reply));
}
return reply;
}
static u8 *master_wait_sync_reply(const tal_t *ctx,
struct peer *peer, const u8 *msg,
enum channel_wire_type replytype)
{
return wait_sync_reply(ctx, msg, replytype,
MASTER_FD, &peer->from_master, "master");
}
static u8 *gossipd_wait_sync_reply(const tal_t *ctx,
struct peer *peer, const u8 *msg,
enum gossip_wire_type replytype)
{
return wait_sync_reply(ctx, msg, replytype,
GOSSIP_FD, &peer->from_gossipd, "gossipd");
}
static struct commit_sigs *calc_commitsigs(const tal_t *ctx,
const struct peer *peer,
u64 commit_index)
{
const tal_t *tmpctx = tal_tmpctx(ctx);
size_t i;
struct bitcoin_tx **txs;
const u8 **wscripts;
const struct htlc **htlc_map;
struct pubkey local_htlckey;
struct privkey local_htlcsecretkey;
struct commit_sigs *commit_sigs = tal(ctx, struct commit_sigs);
if (!derive_simple_privkey(&peer->our_secrets.htlc_basepoint_secret,
&peer->channel->basepoints[LOCAL].htlc,
&peer->remote_per_commit,
&local_htlcsecretkey))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving local_htlcsecretkey");
if (!derive_simple_key(&peer->channel->basepoints[LOCAL].htlc,
&peer->remote_per_commit,
&local_htlckey))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving local_htlckey");
status_trace("Derived key %s from basepoint %s, point %s",
type_to_string(trc, struct pubkey, &local_htlckey),
type_to_string(trc, struct pubkey,
&peer->channel->basepoints[LOCAL].htlc),
type_to_string(trc, struct pubkey,
&peer->remote_per_commit));
txs = channel_txs(tmpctx, &htlc_map, &wscripts, peer->channel,
&peer->remote_per_commit,
commit_index,
REMOTE);
sign_tx_input(txs[0], 0, NULL,
wscripts[0],
&peer->our_secrets.funding_privkey,
&peer->channel->funding_pubkey[LOCAL],
&commit_sigs->commit_sig);
status_trace("Creating commit_sig signature %"PRIu64" %s for tx %s wscript %s key %s",
commit_index,
type_to_string(trc, secp256k1_ecdsa_signature,
&commit_sigs->commit_sig),
type_to_string(trc, struct bitcoin_tx, txs[0]),
tal_hex(trc, wscripts[0]),
type_to_string(trc, struct pubkey,
&peer->channel->funding_pubkey[LOCAL]));
dump_htlcs(peer->channel, "Sending commit_sig");
/* BOLT #2:
*
* A node MUST include one `htlc_signature` for every HTLC transaction
* corresponding to BIP69 lexicographic ordering of the commitment
* transaction.
*/
commit_sigs->htlc_sigs = tal_arr(commit_sigs, secp256k1_ecdsa_signature,
tal_count(txs) - 1);
for (i = 0; i < tal_count(commit_sigs->htlc_sigs); i++) {
sign_tx_input(txs[1 + i], 0,
NULL,
wscripts[1 + i],
&local_htlcsecretkey, &local_htlckey,
&commit_sigs->htlc_sigs[i]);
status_trace("Creating HTLC signature %s for tx %s wscript %s key %s",
type_to_string(trc, secp256k1_ecdsa_signature,
&commit_sigs->htlc_sigs[i]),
type_to_string(trc, struct bitcoin_tx, txs[1+i]),
tal_hex(trc, wscripts[1+i]),
type_to_string(trc, struct pubkey,
&local_htlckey));
assert(check_tx_sig(txs[1+i], 0, NULL, wscripts[1+i],
&local_htlckey,
&commit_sigs->htlc_sigs[i]));
}
tal_free(tmpctx);
return commit_sigs;
}
static void send_commit(struct peer *peer)
{
tal_t *tmpctx = tal_tmpctx(peer);
u8 *msg;
const struct htlc **changed_htlcs;
#if DEVELOPER
/* Hack to suppress all commit sends if dev_disconnect says to */
if (dev_suppress_commit) {
peer->commit_timer = NULL;
tal_free(tmpctx);
return;
}
#endif
/* FIXME: Document this requirement in BOLT 2! */
/* We can't send two commits in a row. */
if (peer->revocations_received != peer->next_index[REMOTE] - 1) {
assert(peer->revocations_received
== peer->next_index[REMOTE] - 2);
status_trace("Can't send commit: waiting for revoke_and_ack");
/* Mark this as done and try again. */
peer->commit_timer = NULL;
start_commit_timer(peer);
tal_free(tmpctx);
return;
}
/* If we wanted to update fees, do it now. */
if (peer->channel->funder == LOCAL
&& peer->desired_feerate != channel_feerate(peer->channel, REMOTE)) {
u8 *msg;
u32 feerate, max = approx_max_feerate(peer->channel);
feerate = peer->desired_feerate;
/* FIXME: We should avoid adding HTLCs until we can meet this
* feerate! */
if (feerate > max)
feerate = max;
if (!channel_update_feerate(peer->channel, feerate))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not afford feerate %u"
" (vs max %u)",
feerate, max);
msg = towire_update_fee(peer, &peer->channel_id, feerate);
enqueue_peer_msg(peer, take(msg));
}
/* BOLT #2:
*
* A node MUST NOT send a `commitment_signed` message which does not
* include any updates.
*/
changed_htlcs = tal_arr(tmpctx, const struct htlc *, 0);
if (!channel_sending_commit(peer->channel, &changed_htlcs)) {
status_trace("Can't send commit: nothing to send");
/* Covers the case where we've just been told to shutdown. */
maybe_send_shutdown(peer);
peer->commit_timer = NULL;
tal_free(tmpctx);
return;
}
peer->next_commit_sigs = calc_commitsigs(peer, peer,
peer->next_index[REMOTE]);
status_trace("Telling master we're about to commit...");
/* Tell master to save this next commit to database, then wait. */
msg = sending_commitsig_msg(tmpctx, peer->next_index[REMOTE],
channel_feerate(peer->channel, REMOTE),
changed_htlcs,
&peer->next_commit_sigs->commit_sig,
peer->next_commit_sigs->htlc_sigs);
/* Message is empty; receiving it is the point. */
master_wait_sync_reply(tmpctx, peer, take(msg),
WIRE_CHANNEL_SENDING_COMMITSIG_REPLY);
status_trace("Sending commit_sig with %zu htlc sigs",
tal_count(peer->next_commit_sigs->htlc_sigs));
peer->next_index[REMOTE]++;
msg = towire_commitment_signed(peer, &peer->channel_id,
&peer->next_commit_sigs->commit_sig,
peer->next_commit_sigs->htlc_sigs);
enqueue_peer_msg(peer, take(msg));
peer->next_commit_sigs = tal_free(peer->next_commit_sigs);
maybe_send_shutdown(peer);
/* Timer now considered expired, you can add a new one. */
peer->commit_timer = NULL;
start_commit_timer(peer);
tal_free(tmpctx);
}
static void start_commit_timer(struct peer *peer)
{
/* Already armed? */
if (peer->commit_timer) {
status_trace("Commit timer already running...");
return;
}
peer->commit_timer = new_reltimer(&peer->timers, peer,
time_from_msec(peer->commit_msec),
send_commit, peer);
}
static u8 *make_revocation_msg(const struct peer *peer, u64 revoke_index)
{
struct pubkey oldpoint, point;
struct sha256 old_commit_secret;
/* Get secret. */
per_commit_secret(&peer->shaseed, &old_commit_secret, revoke_index);
/* Sanity check that it corresponds to the point we sent. */
pubkey_from_privkey((struct privkey *)&old_commit_secret, &point);
if (!per_commit_point(&peer->shaseed, &oldpoint, revoke_index))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Invalid point %"PRIu64" for commit_point",
revoke_index);
status_trace("Sending revocation #%"PRIu64" for %s",