1. We don't need to check for NULL before tal_count(NULL).
2. Use of json_for_each_arr iterator is probably better.
3. Weird indent fixed.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Users are more upset recently with the cost of unilateral closes
than they are the risk of being cheated. While we complete our
anchor implementation so we can use low fees there, let's
get less aggressive (we already have 34 or 18 blocks to close
in the worst case).
The changes are:
- Commit transactions were "2 CONSERVATIVE" now "6 ECONOMICAL".
- HTLC resolution txs were "3 CONSERVATIVE" now "6 ECONOMICAL".
- Penalty txs were "3 CONSERVATIVE" now "12 ECONOMICAL".
- Normal txs were "4 ECONOMICAL" now "12 ECONOMICAL".
There can be no perfect levels, but we have had understandable
complaints recently about how high our default fee levels are.
Changelog-Changed: Protocol: channel feerates reduced to bitcoind's "6 block ECONOMICAL" rate.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: Plugins: `funder` plugin now has new command `funderupdate` which will show current funding configuration and allow you to modify them
Behold! An immaculately concepted plugin for configuring your node to do
amazing things*
*fund channel open requests
Changelog-Added: Plugins: Add `funder` plugin, which allows you to setup a policy for funding v2 channel open requests. Requres --experimental-dual-fund option
If we only add a single input/output for the funding transaction,
we'll only call openchannel_update once, which results in
a crash because the dest->state will never advance to
MULTIFUNDCHANNEL_UPDATED;
Instead, we update to UPDATED before we check for doneness.
It's unlikely but possible that a race condition will result in us not
being at the 'secured' state yet here.
Crashlogs. All required msgs are received (in order)
from peers, but the crash suggests they weren't relayed/processed by the
spender plugin in the order received.
WIRE_TX_SIGNATURES is passed the the plugin via a notification;
WIRE_COMMITMENT_SIGNED is returned as the result of an RPC call.
```
021-03-25T12:12:33.5213247Z lightningd-1: 2021-03-25T11:50:13.351Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-dualopend-chan#3: peer_in WIRE_COMMITMENT_SIGNED
2021-03-25T12:12:33.5221140Z lightningd-1: 2021-03-25T11:50:13.659Z DEBUG 022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59-dualopend-chan#1: peer_in WIRE_COMMITMENT_SIGNED
2021-03-25T12:12:33.5228462Z lightningd-1: 2021-03-25T11:50:14.169Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-dualopend-chan#3: peer_in WIRE_TX_SIGNATURES
2021-03-25T12:12:33.5230957Z lightningd-1: 2021-03-25T11:50:14.375Z DEBUG plugin-spenderp: mfc 275, dest 1: openchannel_update 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d returned.
2021-03-25T12:12:33.5233307Z lightningd-1: 2021-03-25T11:50:14.539Z DEBUG 022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59-dualopend-chan#1: peer_in WIRE_TX_SIGNATURES
2021-03-25T12:12:33.5235120Z lightningd-1: 2021-03-25T11:50:17.240Z INFO plugin-spenderp: Killing plugin: exited during normal operation
2021-03-25T12:12:33.5236707Z lightningd-1: 2021-03-25T11:50:17.260Z **BROKEN** plugin-spenderp: Plugin marked as important, shutting down lightningd!
```
Fixes#4455
You can now activate dual-funded channels using the
`--experimental-dual-fund` flag
Changelog-Changed: Config: `--experimental-dual-fund` runtime flag will enable dual-funded protocol on this node
There is little point in faking a self-payment, but we should also not
crash :-)
Fixes#4438
Changelog-Fixed: keysend: Keysend returns an error when a self-payment is requested
And update all the in-tree callers.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Deprecated: JSON-RPC: `fundchannel_complete` `txid` and `txout` parameters (use `psbt`)
In particular, txprepare gives us a nice way to get a valid PSBT for
testing.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `txprepare` and `withdraw` now return a `psbt` field.
Previously this ported errors around as JSON. A nicer thing to do is to
deconstruct/reconstruct it; this also allows us to create our own errors
from within the multifundchannel family.
There's a version of this that keeps the PSBT in memory and does some
fancy addition/subtraction of unuseable parts for the v2's, however
it's much easier and simpler to simply error on the peer and re-start
from the very beginning.
This only works if we haven't gotten commitments from the peer yet (in
fact either method would only work if we haven't got commitments from
the peer yet), so if we've got commitments from them we simply mark them
as failed an go again.
In a perfect world, we'd remember what inputs we used last time, and
reuse those again on the re-attempt, which would pefectly guarantee both
that the failed opens (ones w/ commitments exchanged) would be canceled
after this completes (and we could re-try the failed again).
As it is, this is not perfect. It is, however, servicable.
We were automatically falling back to bolt12 decoding, clobbering the
fail message. Ultimately resulting in confusing error
messages (expected prefix lni but got lnbtrc). Now we first determine
which decoding we're trying to do, and then only decode accordingly.
Changelog-Fixed: pay: Report the correct decoding error if bolt11 parsing fails.
We were not aborting if we had routehints, even though all routehints
may have been filtered out.
Changelog-Fixed: pay: `pay` will now abort early if the destination is not reachable directly nor via routehints.
We would happily spin on attempts that are doomed to fail because we
don't know the entrypoint. Next up: remove routehints whose
entrypoints are known but unreachable.
The main responsibility of this new function is to mark a payment
process as terminated and set a reasonable error message, that will be
displayed to the caller. We also skip the remaining modifiers since
they might end up clobbering the message.
As pointed out by @cfromknecht [1] there was no formal standardization of
the featurebit, and lnd would try a keysend whenever TLV was supported
by the recipient. This mimics that behavior by checking only that TLV
is enabled.
Changelog-Fixes: keysend: We now attempt to send with keysend even if the node hasn't explicitly opted in by setting a featurebit.
[1] https://github.com/ElementsProject/lightning/issues/4299#issuecomment-781606865
We consolidate to the latest/singular RFC patch for dual-funding, so
there's just a single patchfile for the change. Plus we move back to the
opener setting the desired feerate, the accepter merely declines to
participate if they disagree with the set rate.
Saves a great deal of confusion for regtest users.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: JSON-RPC: If bitcoind won't give a fee estimate in regtest, use minimum.
We get a label clash: easy, just re-serve:
```
2021-02-18T04:29:37.474Z **BROKEN** plugin-offers: Failed invoice_request lnr1qgsqvgnwgcg35z6ee2h3yczraddm72xrfua9uve2rlrm9deu7xyfzrcyyqwtp0rmsgquvuacqcl5cdfzwzmu3v8tqgvpqs8e80dlmxm7ey4xwrqdsqqqqqqqqqqqqqqqq2pqqfqpqynzqzx9rylzy40ernj4jzc3p2dwy3n8x6lqeaywwk725ghx4kx63pcfxgg2z3nsn80jzge06nt3ks8pr6rvnujq48376lpmrr3cq04nurpy783eyr0awh5773lrlmjek07rjf0nx4g9235ulkcs7jp2h5gumjyquhadh846da3jptxm9g0qz5lne4hjhag for offer 1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67: Got JSON error: {\"code\":900,\"message\":\"Duplicate label\",\"data\":{\"label\":\"1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67-08c5193e2255f91ce5590b110a9ae2466736be0cf48e75bcaa22e6ad8da88709-1\",\"bolt12\":\"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\",\"payment_hash\":\"396250395aa046f4c58162a5ae31952d01bd0c8e5213f32e748ec428a9379cd2\",\"msatoshi\":7700446,\"amount_msat\":\"7700446msat\",\"status\":\"unpaid\",\"description\":\"Weekly coffee for rusty!\",\"expires_at\":1614832137,\"local_offer_id\":\"1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67\"}}
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We should actually be including this (as it may define _GNU_SOURCE
etc) before any system headers. But where we include <assert.h> we
often didn't, because check-includes would complain that the headers
included it too.
Weaken that check, and include config.h in C files before assert.h.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We fix up the test by using pay, instead of sendpay (and making pay log
the expected message).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: sendpay no longer extracts updates from errors, the caller should do it from the `raw_message`.
The fetchinvoice and offers plugins disable themselves if the option
isn't enabled (it's enabled by default on EXPERIMENTAL_FEATURES).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: `experimental-offers` enables fetch, payment and creation of (early draft) offers.
Don't include exp directly, use an ifdef in common/bolt12
(like we do for peer and onion wiregen files).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As per lastest revision of the spec, we can specify amounts in invoice
requests even if the offer already specifies it, as long as we exceed
the amount given. This allows for tipping, and amount obfuscation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Means a reshuffle of our logic: we want to multiply by quantity before
conversion for maximum accuracy.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This avoids a footgun where they create an offer then we can't create
the invoice because they don't have a converter plugin.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is experimental for now, but can eventually deprecated
'decodepay' and even decode other kinds of messages.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We split `send_invoice` offers inoo offerout (for want of a better name).
This simplifies the API.
Also took the opportunity to move the `vendor` tag to immediately
follow `description` (our tests use arguments by keywords, so no
change there).
Suggested-by: shesek
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
refund offers are implied send_invoice offers. And send_invoice offers
are implied single-use offers, though it can also make sense to have
a non-send_invoice offer be single-use.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This makes for more useful errors. It prints where it was up to in
the guide, but doesn't print the entire JSON it's scanning.
Suggested-by: Christian Decker
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This will cause blow ups for v2 multifundchannel attempts with failures,
but allows us to return the expected errors for single-shot
fundchannel attempts.
Error handling is coming, i promise
Since we round down in `amount_tx_fee`, find the change fee as the
difference between what we've already paid and what the combined/total
fee would be if the change weight were also added.
Ideally we'd 'cure' the error and re-attempt, except that if this was a
bitcoin-backend 'failure to broadcast' then it really needs user
intervention to figure out what's wrong -- it's possible that the
peer successfully broadcast the transaction
Using onionmessage hook, we get the response and either present it
to the user (invoice) or return the error to the user.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
1. Hoist 7200 constant into the bolt12 heade2.
2. Make preimage the last createinvoice arg, so we could make it optional.
3. Check the validity of the preimage in createinvoice.
4. Always output used flag in listoffers.
5. Rename wallet offer iterators to offer_id iterators.
6. Fix paramter typos.
7. Rename `local_offer_id` parameter to `localofferid`.
8. Add reference constraints on local_offer_id db fields.
9. Remove cut/paste comment.
10. Clarify source of fatal() messages in wallet.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Note that we remove the redundant "is this the correct chain?"
check, since bolt11_decode and bolt12_decode do that internally
anyway (this was changed in 924cc04bd2).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We were blindly initiating the keysend payment, which could lead to
confusing outcomes. This adds a very specific error message to the
error returned.
Changelog-Fixed: keysend: Keysend now checks whether the destination supports keysend before attempting a payment. If not a more informative error is returned.
We were not checking that outputs is indeed an array, and just going
ahead creating the array of outputs. Since `tok->size` for a string is
0 we ended up ignoring the argument altogether and thus the created
transaction would end up only with a single change output.
Fixes#4258
When we support bolt12, this won't exist. We only need min_final_cltv_expiry,
routes and features, so put them into struct payment explicitly.
We move the default final ctlv out to the caller, too, which is clearer.
e.g. keysend was using this value, but it was hard to tell.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We'll use it for figuring out whether or not to set a utxo witness
minimum, which comes much before we were setting this field.
Now we set the protocol as soon as we can reasonably deduce it.
we only want to sign the inputs that we've reserved via utxopsbt or
fundpsbt. we mark them with a flag (reusing the now defunct max-len
flag is fine), then look for inputs with that flag to pass to signonly
We only have output scripts for v1 protocols after the
fundchannel_start/openchannel_init round. We need to add them before
we get into the openchannel_update rounds, however, so we do that here.
I previously mistyped the rather lengthy conditions for failures, so
let's dissect it into its smaller components and add rationale behind
the individual parts of the decision.
This adds a new state `PAYMENT_STEP_RETRY_GETROUTE` which is used to
retry just that one step, without spawning a completely new
attempt. It's a new state so that modifiers do not act on it twice.
Changelog-Fixed: pay: Improved the performance of the `pay` command considerably by avoiding conflicting changes to our local network view.
We were delaying the channel_hint update till after the `createonion`
call which gave us the same situation we had with concurrent
`getroute` calls. Now we update the hints as soon as the plugins have
had their say in the route construction. If we still fail, either
because a modifier changed the route causing the failure, or because
we interleaved the route computation for multiple parts, we reset the
attempt and retry inline (i.e., without creating a new sub-payment).
Notice that interleaved route computations now only happen if the
modifier makes an async call to some RPC or similar.
1. One place returned false instead of -1.
2. The names implied it returned a bool, and it doesn't.
Fix both, and curse C's loose typing a little.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Note that check-whitespace and check-bolt already do this, so we
can eliminate redundant lines in common/Makefile and bitcoin/Makefile.
We also include the plugin headers in ALL_C_HEADERS so they get
checked.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Technically there *are* two feerates that we need to know:
- the feerate to use for the funding transaction, and
- the feerate to tell our peer to use for our commitment txs/htlc txs
As written, `multifundchannel` uses the same feerate for both. This
optional parameter will allow us to differentiate between the two, which
will be exceedingly handy for anchor output worlds. ;)
FIXME: test this
Changelog-Added: JSON API: `multifundchannel` has a new optional argument, 'commitment_feerate', which can be used to differentiate between the funding feerate and the channel's initial commitment feerate
This is a fairly direct translation. Even so, it should be faster in
most cases, and and we can do more sophisticated things if we want.
This also handles disabled channels better.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: plugins: `pay` will now try disabled channels as a last resort.
Finally, extends the 'close_to' functionality up to the flagship 'open a
channel' command.
Changelog-Added: JSON-API `fundchannel` now accepts an optional 'close_to' param, a bitcoin address that the channel funding should be sent to on close. Requires `opt_upfront_shutdownscript`
We're rarely in a hurry here, and bitcoind is aggressive with fees.
You can always spend this output if you really have to, using CPFP.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: Protocol: mutual closing feerate reduced to "slow" to avoid overpaying.
I got a corrupt file, which looked like multiple concurrent attempts
to build it. So instead, build it in one command, but also use
VERBOSE so we print correctly with V=1 (and --quiet).
Also move into plugins/ where it logically belongs.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Deprecated, but this can happen:
```
==1578== Conditional jump or move depends on uninitialised value(s)
==1578== at 0x12B30E: amount_msat_add (amount.c:224)
==1578== by 0x11270B: add_amount_sent (pay.c:1734)
==1578== by 0x112D89: listsendpays_done (pay.c:1831)
==1578== by 0x114F4B: handle_rpc_reply (libplugin.c:555)
==1578== by 0x115704: rpc_read_response_one (libplugin.c:685)
==1578== by 0x115821: rpc_conn_read_response (libplugin.c:705)
==1578== by 0x148E40: next_plan (io.c:59)
==1578== by 0x1499BD: do_plan (io.c:407)
==1578== by 0x1499FB: io_ready (io.c:417)
==1578== by 0x14BBC1: io_loop (poll.c:445)
==1578== by 0x117A82: plugin_main (libplugin.c:1322)
==1578== by 0x113ABC: main (pay.c:2096)
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: #3926
(probably)
Changelog-Fixed: pay: Also limit the number of splits if the payee seems to have a low number of channels that can enter it, given the max-concurrent-htlcs limit.
The routehints paymod shares the storage of the array d->routehints and
p->invoice->routes, but once it operates, it possibly leaves it as a stale
pointer to memory it used to have.
Since other paymods may be interested in the invoice details, including
the routehints in the invoice, we should ensure the p->invoice->routes
remains valid whenever we try mutating that array.
As revealed by the failure of tests in #3936, where we ended up trying
to send a partial payment using legacy style, we are not handling
style properly.
1. BOLT9 has features, so we can *know* that the destination supports
MPP. We may not have seen a node_announcement.
2. We can't assume that nodes inside routehints support TLV.
3. We can't assume direct peers support TLV.
The keysend code tried to fix this up, so I'm not sure that this caused
the issue in #3968, though.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: `pay` will now make reliable multi-part payments to nodes it doesn't have a node_announcement for.
This will update the fee output if it exists, rather than unilaterally
adding a new one.
Also, if the fee output already exists, we should make sure that it
doesn't interfere with the outnums of the other outputs
Fixes: #2679
Changelog-Added: JSON-RPC: New `multiwithdraw` command to batch multiple onchain sends in a single transaction. Note it shuffles inputs and outputs, does not use BIP69.
Changelog-Added: We now have `multifundchannel` as a builtin plugin command to fund multiple channels to different peers all in a single onchain transaction.
Header from folded patch 'fixup-use-json_add_psbt.patch':
fixup!
Header from folded patch 'use-goto-no-ok-chain.patch':
fixup!
Header from folded patch 'destinations-at-parse-time.patch':
fixup!
Header from folded patch 'multifundchannel__use_jsmntoks_to_pass_through_json_string,_not_strings.patch':
multifundchannel: use jsmntoks to pass through json string, not strings
Passing in "" for utxos would crash lightningd on the command-line
otherwise. Now returns an error.
Header from folded patch 'update_plugins-multifundchannel.c.patch':
Update plugins/multifundchannel.c
Co-authored-by: Darosior <darosior@protonmail.com>
Changelog-Deprecated: plugin: `bcli` replacements should note that `sendrawtransaction` now has a second required Boolean argument, `allowhighfees`, which if `true`, means ignore any fee limits and just broadcast the transaction. Use `--deprecated-apis` to use older `bcli` replacement plugins that only support a single argument.
This removes the reservation cleanup at startup, too, now they're all
using 'reserved_til'.
This changes test_withdraw, since it asserted that outputs were marked
spent as soon as we broadcast a transaction: now they're reserved until
it's mined. Similarly, test_addfunds_from_block assumed we'd see funds
as soon as we broadcast the tx.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: JSON-RPC: `withdraw` now randomizes input and output order, not BIP69.
This is a little lazy, but simpler than extracting the common parts
or making withdraw a plugin which calls txprepare (which should be
deprecated soon in favor of fundpsbt etc).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Some minor phrasing differences cause test changes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: txprepare reservations stay across restarts: use fundpsbt/reservepsbt/unreservepsbt
Changelog-Removed: txprepare `destination` `satoshi` argument form removed (deprecated v0.7.3)
This uses `fundpsbt` and similar to simulate the txprepare command.
It has one difference (when complete), in that it those reservations
are now timed and don't get reset on restart.
It also doesn't have the restriction that `all` can only be used with
no other output, as I didn't realize that when I implemented it!
Note that change is now inserted in a random position, not sorted
into BIP69 order.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This avoids overwriting the ones in git, and generally makes things neater.
We have convenience headers wire/peer_wire.h and wire/onion_wire.h to
avoid most #ifdefs: simply include those.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We were using `tal_fmt` to truncate off the last byte of the
response (newline), which required an allocation, a call to `vsnprintf` and a
copy of the block contents. This being >2MB in size on mainnet was rather
expensive.
We now just signal the end of the string by overwriting the trailing newline,
and stealing directly onto the result.
We create ALL_PROGRAMS, ALL_TEST_PROGRAMS, ALL_C_SOURCES and
ALL_C_HEADERS. Then the toplevel Makefile knows which are
autogenerated (by wildcard), so it can have all the rules to clean
them or check the source as necessary.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Using `waitblockheight 0` is a very slightly faster query than `getinfo`.
Also, avoid querying blockheight for child payments (allow `waitblockheight`
paymod to provide the blockheight returned from the `waitblockheight`, and
just resample the starting blockheight from the parent).
Changelog-None: pointless micro-optimization
This was checked with `gcc -S -O2` to see how an optimized build
would compile the function.
The original code completed calls into each child (and the `.s`
file showed that GCC 9.x was not smart enough to do early-out).
This modification explicitly does early-out, and avoids call-return
stack overhead for the common case where a payment is an ancestor
of a long line of single-child payments due to retrying.
Changelog-None: pointless micro-optimization
This is the simplest possible fix: increase the target amount until we get
the desired number of parts, while still bucketizing payments together that
are in approximately the same size.
The current logic puts all payments that are in the range x < amount <= 16*x
in the same bucket, making them harder to distinguish.
Changelog-Fixed: pay: The `presplit` modifier now supports large payments without exhausting the available HTLCs.
