Upon receiving UNKNOWN_NEXT_PEER, TEMPORARY_NODE_FAILURE
or TEMPORARY_CHANNEL_FAILURE, remember the trampoline route
that was used, and try other routes before raising the
trampoline fee.
Before this commit, we used to raise the trampoline fee
upon receiving any error message, in order to ensure
termination of the payment loop.
Note that we will still retry failing routes after we have
raised the trampoline fee. This choice is questionable, it
is unclear if doing so significantly increases the probability
of success.
Tests: add a test for trampoline handling of UNKNOWN_NEXT_PEER
- better error handling: previously we stopped all attempts on any of
TRAMPOLINE_EXPIRY_TOO_SOON, UNKNOWN_NEXT_PEER, TEMPORARY_NODE_FAILURE.
Instead we should retry (but see code comments).
- previously payments failed if ALL of the following criteria applied:
- sender is paying via trampoline, but not via the ACINQ node (which is
special cased)
- receiver only has private channels and has put r_tags into invoice, along
with setting the trampoline feature bit in the invoice, however the receiver
is not connected to any trampoline forwarders directly
The sender would then assume that the private routing hints in the invoice
correspond to trampoline forwarders.
- also, previously if both the sender and the recipient used trampoline and
they shared a trampoline forwarder (that they were both connected to), the
private channels the recipient had (with nodes other than the shared TF)
would never be attempted.
Upfront shutdown script is a script provided on channel opening,
which will be used by the peer to enforce us closing to this script
on collaborative channel close.
I believe this now implements all the checks listed in BOLT-02 for
update_add_htlc, however, the BOLT is sometimes ambiguous,
and actually the checks listed there IMO are insufficient.
There are still some TODOs, in part because of the above.
we were looking at inconsistent ctns
and we were looking at the wrong subject's ctx
all the FIXMEs and TODOs here will still warrant some attention.
(note that test_DesyncHTLCs was passing incorrectly:
the "assertRaises" was catching a different exception)
1. In lnhtlc, sent_in_ctn and failed_in_ctn need to look at the
remote ctx, and they need to be called when we receive a revocation,
not when we send one.
2. In lnchannel, we use 3 lnworker callbacks:
- payment sent/payment failed (called when we receive a revocation)
- payment received (called when we send a revocation)
3. Make revoke_current_commitment return a single value.
The second value was only used in tests, there is no need
to bloat the code with that
- persisted states are saved
- state transitions are checked
- transient states are stored in channel.peer_state
- new channel states: 'PREOPENING', 'FUNDED' and 'REDEEMED'
- upgrade storage to version 21
The few other cases that used SimpleConfig.get_instance() now
either get passed a config instance, or they try to get a reference
to something else that has a reference to a config.
(see lnsweep, qt/qrcodewidget, qt/qrtextedit)
"current" used to be "oldest_unrevoked"; and pending was "oldest_unrevoked + 1"
but this was very confusing...
so now we have "oldest_unrevoked", "latest", and "next"
where "next" is "latest + 1"
"oldest_unrevoked" and "latest" are either the same or are offset by 1
(but caller should know which one they need)
rm "got_sig_for_next" - it was a redundant sanity check, that really
just complicated things
rm "local_commitment", "remote_commitment", "set_local_commitment",
"set_remote_commitment" - just use "get_latest_commitment" instead
in the old code,
`self.hm.received_in_ctn(self.config[REMOTE].ctn + 1)`
did not really make sense as "received_in_ctn" compares the argument against the LOCAL ctn
