core-lightning/doc/lightning-fundchannel.7.md
Rusty Russell 3e57496af9 plugins: don't let multifundchannel open a new anchor channel without reserves.
If we're opening a channel with a peer which support anchors (and
we do), we tell fundpsbt/utxopsbt to enforce the emergency reserve;
this matters, as it doesn't know about the channel yet, and thus
won't (if it's our first anchor channel).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: JSON-RPC: `fundchannel` and `multifundchannel` will refuse to spend funds below `min-emergency-msat` if we have any anchor channels (or are opening one).
2023-06-29 11:28:47 -04:00

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lightning-fundchannel -- Command for establishing a lightning channel
=====================================================================
SYNOPSIS
--------
**fundchannel** *id* *amount* [*feerate*] [*announce*] [*minconf*]
[*utxos*] [*push\_msat*] [*close\_to*] [*request\_amt*] [*compact\_lease*]
[*reserve*]
DESCRIPTION
-----------
The **fundchannel** RPC command opens a payment channel with a peer by
committing a funding transaction to the blockchain as defined in BOLT
\#2.
If not already connected, **fundchannel** will automatically attempt
to connect if C-lightning knows a way to contact the node (either from
normal gossip, or from a previous **connect** call).
This auto-connection can fail if C-lightning does not know how to contact
the target node; see lightning-connect(7).
Once the
transaction is confirmed, normal channel operations may begin. Readiness
is indicated by **listpeers** reporting a *state* of `CHANNELD_NORMAL`
for the channel.
*id* is the peer id obtained from **connect**.
*amount* is the amount in satoshis taken from the internal wallet to
fund the channel (but if we have any anchor channels, this will always leave at least `min-emergency-msat` as change). The string *all* can be used to specify all available
funds (or 16777215 satoshi if more is available and large channels were not negotiated with the peer). Otherwise, it is in
satoshi precision; it can be a whole number, a whole number ending in
*sat*, a whole number ending in *000msat*, or a number with 1 to 8
decimal places ending in *btc*. The value cannot be less than the dust
limit, currently set to 546, nor more than 16777215 satoshi (unless large
channels were negotiated with the peer).
*feerate* is an optional feerate used for the opening transaction and
(unless *option\_anchors\_zero\_fee\_htlc\_tx* is negotiated), as initial feerate
for commitment and HTLC transactions (see NOTES in lightning-feerates(7)).
The default is *normal*.
*announce* is an optional flag that triggers whether to announce this
channel or not. Defaults to `true`. An unannounced channel is considered
private.
*minconf* specifies the minimum number of confirmations that used
outputs should have. Default is 1.
*utxos* specifies the utxos to be used to fund the channel, as an array
of "txid:vout".
*push\_msat* is the amount of millisatoshis to push to the channel peer at
open. Note that this is a gift to the peer -- these satoshis are
added to the initial balance of the peer at channel start and are largely
unrecoverable once pushed.
*close\_to* is a Bitcoin address to which the channel funds should be sent to
on close. Only valid if both peers have negotiated `option_upfront_shutdown_script`.
Returns `close_to` set to closing script iff is negotiated.
*request\_amt* is an amount of liquidity you'd like to lease from the peer.
If peer supports `option_will_fund`, indicates to them to include this
much liquidity into the channel. Must also pass in *compact\_lease*.
*compact\_lease* is a compact represenation of the peer's expected
channel lease terms. If the peer's terms don't match this set, we will
fail to open the channel.
*reserve* is the amount we want the peer to maintain on its side of the channel.
Default is 1% of the funding amount. It can be a whole number, a whole number
ending in *sat*, a whole number ending in *000msat*, or a number with 1 to 8
decimal places ending in *btc*.
This example shows how to use lightning-cli to open new channel with peer 03f...fc1 from one whole utxo bcc1...39c:0
(you can use **listfunds** command to get txid and vout):
lightning-cli -k fundchannel id=03f...fc1 amount=all feerate=normal utxos='["bcc1...39c:0"]'
RETURN VALUE
------------
[comment]: # (GENERATE-FROM-SCHEMA-START)
On success, an object is returned, containing:
- **tx** (hex): The raw transaction which funded the channel
- **txid** (txid): The txid of the transaction which funded the channel
- **outnum** (u32): The 0-based output index showing which output funded the channel
- **channel\_id** (hex): The channel\_id of the resulting channel (always 64 characters)
- **close\_to** (hex, optional): The raw scriptPubkey which mutual close will go to; only present if *close\_to* parameter was specified and peer supports `option_upfront_shutdown_script`
- **mindepth** (u32, optional): Number of confirmations before we consider the channel active.
[comment]: # (GENERATE-FROM-SCHEMA-END)
The following error codes may occur:
- -1: Catchall nonspecific error.
- 300: The maximum allowed funding amount is exceeded.
- 301: There are not enough funds in the internal wallet (including fees) to create the transaction.
- 302: The output amount is too small, and would be considered dust.
- 303: Broadcasting of the funding transaction failed, the internal call to bitcoin-cli returned with an error.
- 313: The `min-emergency-msat` reserve not be preserved (and we have or are opening anchor channels).
Failure may also occur if **lightningd** and the peer cannot agree on
channel parameters (funding limits, channel reserves, fees, etc.).
SEE ALSO
--------
lightning-connect(7), lightning-listfunds(), lightning-listpeers(7),
lightning-feerates(7), lightning-multifundchannel(7)
RESOURCES
---------
Main web site: <https://github.com/ElementsProject/lightning>
[comment]: # ( SHA256STAMP:a8329cdb3f13f5bd0047824bed82c2e10516af2735dc59aa2cd71e4cc4f0250a)