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lightningd/channel.c: add callbacks for when HTLCs fully committed/removed.

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The three cases we care about only happen on specific transitions:
1. They can no longer spend our failed HTLC: we can fail the source now.
2. They are fully committed to their new HTLC htlc: we can forward now.
3. They can no longer timeout their fulfilled HTLC: the funds are ours.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2017-04-01 20:59:39 +10:30
parent 82a467f131
commit ada1eb5106
4 changed files with 86 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
lightningd/channel.c
View File

@ -619,11 +619,36 @@ static void htlc_incstate(struct channel *channel,
}
}
static void check_lockedin(const struct htlc *h,
struct peer *peer,
void (*oursfail)(struct peer *peer,
const struct htlc *htlc),
void (*theirslocked)(struct peer *peer,
const struct htlc *htlc),
void (*theirsfulfilled)(struct peer *peer,
const struct htlc *htlc))
{
/* If it was fulfilled, we handled it immediately. */
if (h->state == RCVD_REMOVE_ACK_REVOCATION && !h->r)
oursfail(peer, h);
else if (h->state == RCVD_ADD_ACK_REVOCATION)
theirslocked(peer, h);
else if (h->state == RCVD_REMOVE_ACK_COMMIT && h->r)
theirsfulfilled(peer, h);
}
/* FIXME: Commit to storage when this happens. */
static bool change_htlcs(struct channel *channel,
enum side sidechanged,
const enum htlc_state *htlc_states,
size_t n_hstates)
size_t n_hstates,
struct peer *peer,
void (*oursfail)(struct peer *peer,
const struct htlc *htlc),
void (*theirslocked)(struct peer *peer,
const struct htlc *htlc),
void (*theirsfulfilled)(struct peer *peer,
const struct htlc *htlc))
{
struct htlc_map_iter it;
struct htlc *h;
@ -636,6 +661,10 @@ static bool change_htlcs(struct channel *channel,
for (i = 0; i < n_hstates; i++) {
if (h->state == htlc_states[i]) {
htlc_incstate(channel, h, sidechanged);
check_lockedin(h, peer,
oursfail,
theirslocked,
theirsfulfilled);
changed = true;
}
}
@ -651,10 +680,16 @@ bool channel_sent_commit(struct channel *channel)
SENT_ADD_REVOCATION,
SENT_REMOVE_HTLC };
status_trace("sent commit");
return change_htlcs(channel, REMOTE, states, ARRAY_SIZE(states));
return change_htlcs(channel, REMOTE, states, ARRAY_SIZE(states),
NULL, NULL, NULL, NULL);
}
bool channel_rcvd_revoke_and_ack(struct channel *channel)
bool channel_rcvd_revoke_and_ack(struct channel *channel,
struct peer *peer,
void (*oursfail)(struct peer *peer,
const struct htlc *htlc),
void (*theirslocked)(struct peer *peer,
const struct htlc *htlc))
{
const enum htlc_state states[] = { SENT_ADD_COMMIT,
SENT_REMOVE_ACK_COMMIT,
@ -662,11 +697,15 @@ bool channel_rcvd_revoke_and_ack(struct channel *channel)
SENT_REMOVE_COMMIT };
status_trace("received revoke_and_ack");
return change_htlcs(channel, LOCAL, states, ARRAY_SIZE(states));
return change_htlcs(channel, LOCAL, states, ARRAY_SIZE(states),
peer, oursfail, theirslocked, NULL);
}
/* FIXME: We can actually merge these two... */
bool channel_rcvd_commit(struct channel *channel)
bool channel_rcvd_commit(struct channel *channel,
struct peer *peer,
void (*theirsfulfilled)(struct peer *peer,
const struct htlc *htlc))
{
const enum htlc_state states[] = { RCVD_ADD_REVOCATION,
RCVD_REMOVE_HTLC,
@ -674,7 +713,8 @@ bool channel_rcvd_commit(struct channel *channel)
RCVD_REMOVE_REVOCATION };
status_trace("received commit");
return change_htlcs(channel, LOCAL, states, ARRAY_SIZE(states));
return change_htlcs(channel, LOCAL, states, ARRAY_SIZE(states),
peer, NULL, NULL, theirsfulfilled);
}
bool channel_sent_revoke_and_ack(struct channel *channel)
@ -684,7 +724,8 @@ bool channel_sent_revoke_and_ack(struct channel *channel)
RCVD_ADD_COMMIT,
RCVD_REMOVE_ACK_COMMIT };
status_trace("sent revoke_and_ack");
return change_htlcs(channel, REMOTE, states, ARRAY_SIZE(states));
return change_htlcs(channel, REMOTE, states, ARRAY_SIZE(states),
NULL, NULL, NULL, NULL);
}
static char *fmt_channel_view(const tal_t *ctx, const struct channel_view *view)

25
lightningd/channel.h
View File

@ -10,6 +10,7 @@
#include <lightningd/derive_basepoints.h>
#include <stdbool.h>
struct peer;
struct signature;
/* View from each side */
@ -330,18 +331,34 @@ bool channel_sent_commit(struct channel *channel);
/**
* channel_rcvd_revoke_and_ack: accept ack on remote committed changes.
* @channel: the channel
* @peer: argument to pass through to @ourhtlcfail & @theirhtlclocked
* @oursfail: callback for any unfilfilled htlcs which are now fully removed.
* @theirslocked: callback for any new htlcs which are now fully committed.
*
* This is where we commit to pending changes we've added; returns true if
* anything changed. */
bool channel_rcvd_revoke_and_ack(struct channel *channel);
* anything changed.
*/
bool channel_rcvd_revoke_and_ack(struct channel *channel,
struct peer *peer,
void (*oursfail)(struct peer *peer,
const struct htlc *htlc),
void (*theirslocked)(struct peer *peer,
const struct htlc *htlc));
/**
* channel_rcvd_commit: commit all local outstanding changes.
* @channel: the channel
* @peer: argument to pass through to @theirsfulfilled
* @theirsfulfilled: they are irrevocably committed to removal of htlc.
*
* This is where we commit to pending changes we've added; returns true if
* anything changed. */
bool channel_rcvd_commit(struct channel *channel);
* anything changed. @theirsfulfilled is called for any HTLC we fulfilled
* which they are irrevocably committed to, and is in our current commitment.
*/
bool channel_rcvd_commit(struct channel *channel,
struct peer *peer,
void (*theirsfulfilled)(struct peer *peer,
const struct htlc *htlc));
/**
* channel_sent_revoke_and_ack: sent ack on local committed changes.

3
lightningd/channel/channel.c
View File

@ -369,7 +369,8 @@ static void handle_peer_commit_sig(struct peer *peer, const u8 *msg)
const u8 **wscripts;
size_t i;
if (!channel_rcvd_commit(peer->channel)) {
/* FIXME: Handle theirsfulfilled! */
if (!channel_rcvd_commit(peer->channel, peer, NULL)) {
/* BOLT #2:
*
* A node MUST NOT send a `commitment_signed` message which

26
lightningd/test/run-channel.c
View File

@ -81,6 +81,10 @@ static u64 feerates[] = {
9651936
};
static void do_nothing(struct peer *peer, const struct htlc *htlc)
{
}
/* BOLT #3:
*
* htlc 0 direction: remote->local
@ -150,11 +154,11 @@ static const struct htlc **include_htlcs(struct channel *channel, enum side side
/* Now make HTLCs fully committed. */
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_commit(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, NULL);
channel_rcvd_commit(channel, NULL, NULL);
channel_sent_revoke_and_ack(channel);
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, do_nothing);
return htlcs;
}
@ -236,27 +240,27 @@ static void send_and_fulfill_htlc(struct channel *channel,
if (sender == LOCAL) {
/* Step through a complete cycle. */
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_commit(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, NULL);
channel_rcvd_commit(channel, NULL, NULL);
channel_sent_revoke_and_ack(channel);
assert(channel_fulfill_htlc(channel, REMOTE, 1337, &r)
== CHANNEL_ERR_REMOVE_OK);
channel_rcvd_commit(channel);
channel_rcvd_commit(channel, NULL, NULL);
channel_sent_revoke_and_ack(channel);
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, NULL);
assert(channel_get_htlc(channel, sender, 1337)->state
== RCVD_REMOVE_ACK_REVOCATION);
} else {
channel_rcvd_commit(channel);
channel_rcvd_commit(channel, NULL, NULL);
channel_sent_revoke_and_ack(channel);
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, do_nothing);
assert(channel_fulfill_htlc(channel, LOCAL, 1337, &r)
== CHANNEL_ERR_REMOVE_OK);
channel_sent_commit(channel);
channel_rcvd_revoke_and_ack(channel);
channel_rcvd_commit(channel);
channel_rcvd_revoke_and_ack(channel, NULL, NULL, NULL);
channel_rcvd_commit(channel, NULL, do_nothing);
channel_sent_revoke_and_ack(channel);
assert(channel_get_htlc(channel, sender, 1337)->state
== SENT_REMOVE_ACK_REVOCATION);