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796f18e559
89372213048adf37a47427112a1ff836ee84c50e doc: add release notes for 29415 (Vasil Dimov)
582016fa5f013817db650bbba0a40d9195c18e2e test: add unit test for the private broadcast storage (Vasil Dimov)
e74d54e04896a86cad4e4b1bd9641afcc3a026c2 test: add functional test for private broadcast (Vasil Dimov)
818b780a05db126dcfe7efe12c46c84b5cfc3de6 rpc: use private broadcast from sendrawtransaction RPC if -privatebroadcast is ON (Vasil Dimov)
eab595f9cf13f7cb1d25a0db51409535cfe053b1 net_processing: retry private broadcast (Vasil Dimov)
37b79f9c39db5a4a61d360a6a29c8853bb5c7ac0 net_processing: stop private broadcast of a transaction after round-trip (Vasil Dimov)
2de53eee742da11b0e3f6fc44c39f2b5b5929da1 net_processing: handle ConnectionType::PRIVATE_BROADCAST connections (Vasil Dimov)
30a9853ad35365af8545e8e766d75cf398968480 net_processing: move a debug check in VERACK processing earlier (Vasil Dimov)
d1092e5d48ce67bd517068550c78bfcab062a554 net_processing: modernize PushNodeVersion() (Vasil Dimov)
9937a12a2fd5a0033f37f4dda5d75bfc5f15c3b6 net_processing: move the debug log about receiving VERSION earlier (Vasil Dimov)
a098f37b9e240291077a7f440e9f57e61f30e158 net_processing: reorder the code that handles the VERSION message (Vasil Dimov)
679ce3a0b8df6e8cab07965301382d2036ef2368 net_processing: store transactions for private broadcast in PeerManager (Vasil Dimov)
a3faa6f944a672faccac5dd201c8d33a638d9091 node: extend node::TxBroadcast with a 3rd option (Vasil Dimov)
95c051e21051bd469fda659fe7c495d5e264d221 net_processing: rename RelayTransaction() to better describe what it does (Vasil Dimov)
bb49d26032c57714c62a4b31ff1fdd969751683f net: implement opening PRIVATE_BROADCAST connections (Vasil Dimov)
01dad4efe2b38b7a71c96b6222147f395e0c11d9 net: introduce a new connection type for private broadcast (Vasil Dimov)
94aaa5d31b6ff1d0122319fc70e70a7e27e1a0ba init: introduce a new option to enable/disable private broadcast (Vasil Dimov)
d6ee490e0a9a81b69a4751087918303163ba8869 log: introduce a new category for private broadcast (Vasil Dimov)
Pull request description:
_Parts of this PR are isolated in independent smaller PRs to ease review:_
* [x] _https://github.com/bitcoin/bitcoin/pull/29420_
* [x] _https://github.com/bitcoin/bitcoin/pull/33454_
* [x] _https://github.com/bitcoin/bitcoin/pull/33567_
* [x] _https://github.com/bitcoin/bitcoin/pull/33793_
---
To improve privacy, broadcast locally submitted transactions (from the `sendrawtransaction` RPC) to the P2P network only via Tor or I2P short-lived connections, or to IPv4/IPv6 peers but through the Tor network.
* Introduce a new connection type for private broadcast of transactions with the following properties:
* started whenever there are local transactions to be sent
* opened to Tor or I2P peers or IPv4/IPv6 via the Tor proxy
* opened regardless of max connections limits
* after handshake is completed one local transaction is pushed to the peer, `PING` is sent and after receiving `PONG` the connection is closed
* ignore all incoming messages after handshake is completed (except `PONG`)
* Broadcast transactions submitted via `sendrawtransaction` using this new mechanism, to a few peers. Keep doing this until we receive back this transaction from one of our ordinary peers (this takes about 1 second on mainnet).
* The transaction is stored in peerman and does not enter the mempool.
* Once we get an `INV` from one of our ordinary peers, then the normal flow executes: we request the transaction with `GETDATA`, receive it with a `TX` message, put it in our mempool and broadcast it to all our existent connections (as if we see it for the first time).
* After we receive the full transaction as a `TX` message, in reply to our `GETDATA` request, only then consider the transaction has propagated through the network and remove it from the storage in peerman, ending the private broadcast attempts.
The messages exchange should look like this:
```
tx-sender >--- connect -------> tx-recipient
tx-sender >--- VERSION -------> tx-recipient (dummy VERSION with no revealing data)
tx-sender <--- VERSION -------< tx-recipient
tx-sender <--- WTXIDRELAY ----< tx-recipient (maybe)
tx-sender <--- SENDADDRV2 ----< tx-recipient (maybe)
tx-sender <--- SENDTXRCNCL ---< tx-recipient (maybe)
tx-sender <--- VERACK --------< tx-recipient
tx-sender >--- VERACK --------> tx-recipient
tx-sender >--- INV/TX --------> tx-recipient
tx-sender <--- GETDATA/TX ----< tx-recipient
tx-sender >--- TX ------------> tx-recipient
tx-sender >--- PING ----------> tx-recipient
tx-sender <--- PONG ----------< tx-recipient
tx-sender disconnects
```
Whenever a new transaction is received from `sendrawtransaction` RPC, the node will send it to a few (`NUM_PRIVATE_BROADCAST_PER_TX`) recipients right away. If after some time we still have not heard anything about the transaction from the network, then it will be sent to 1 more peer (see `PeerManagerImpl::ReattemptPrivateBroadcast()`).
A few considerations:
* The short-lived private broadcast connections are very cheap and fast wrt network traffic. It is expected that some of those peers could blackhole the transaction. Just one honest/proper peer is enough for successful propagation.
* The peers that receive the transaction could deduce that this is initial transaction broadcast from the transaction originator. This is ok, they can't identify the sender.
---
<details>
<summary>How to test this?</summary>
Thank you, @stratospher and @andrewtoth!
Start `bitcoind` with `-privatebroadcast=1 -debug=privatebroadcast`.
Create a wallet and get a new address, go to the Signet faucet and request some coins to that address:
```bash
build/bin/bitcoin-cli -chain="signet" createwallet test
build/bin/bitcoin-cli -chain="signet" getnewaddress
```
Get a new address for the test transaction recipient:
```bash
build/bin/bitcoin-cli -chain="signet" loadwallet test
new_address=$(build/bin/bitcoin-cli -chain="signet" getnewaddress)
```
Create the transaction:
```bash
# Option 1: `createrawtransaction` and `signrawtransactionwithwallet`:
txid=$(build/bin/bitcoin-cli -chain="signet" listunspent | jq -r '.[0] | .txid')
vout=$(build/bin/bitcoin-cli -chain="signet" listunspent | jq -r '.[0] | .vout')
echo "txid: $txid"
echo "vout: $vout"
tx=$(build/bin/bitcoin-cli -chain="signet" createrawtransaction "[{\"txid\": \"$txid\", \"vout\": $vout}]" "[{\"$new_address\": 0.00001000}]" 0 false)
echo "tx: $tx"
signed_tx=$(build/bin/bitcoin-cli -chain="signet" signrawtransactionwithwallet "$tx" | jq -r '.hex')
echo "signed_tx: $signed_tx"
# OR Option 2: `walletcreatefundedpsbt` and `walletprocesspsbt`:
# This makes it not have to worry about inputs and also automatically sends back change to the wallet.
# Start `bitcoind` with `-fallbackfee=0.00003000` for instance for 3 sat/vbyte fee.
psbt=$(build/bin/bitcoin-cli -chain="signet" walletcreatefundedpsbt "[]" "[{\"$new_address\": 0.00001000}]" | jq -r '.psbt')
echo "psbt: $psbt"
signed_tx=$(build/bin/bitcoin-cli -chain="signet" walletprocesspsbt "$psbt" | jq -r '.hex')
echo "signed_tx: $signed_tx"
```
Finally, send the transaction:
```bash
raw_tx=$(build/bin/bitcoin-cli -chain="signet" sendrawtransaction "$signed_tx")
echo "raw_tx: $raw_tx"
```
</details>
---
<details>
<summary>High-level explanation of the commits</summary>
* New logging category and config option to enable private broadcast
* `log: introduce a new category for private broadcast`
* `init: introduce a new option to enable/disable private broadcast`
* Implement the private broadcast connection handling on the `CConnman` side:
* `net: introduce a new connection type for private broadcast`
* `net: implement opening PRIVATE_BROADCAST connections`
* Prepare `BroadcastTransaction()` for private broadcast requests:
* `net_processing: rename RelayTransaction to better describe what it does`
* `node: extend node::TxBroadcast with a 3rd option`
* `net_processing: store transactions for private broadcast in PeerManager`
* Implement the private broadcast connection handling on the `PeerManager` side:
* `net_processing: reorder the code that handles the VERSION message`
* `net_processing: move the debug log about receiving VERSION earlier`
* `net_processing: modernize PushNodeVersion()`
* `net_processing: move a debug check in VERACK processing earlier`
* `net_processing: handle ConnectionType::PRIVATE_BROADCAST connections`
* `net_processing: stop private broadcast of a transaction after round-trip`
* `net_processing: retry private broadcast`
* Engage the new functionality from `sendrawtransaction`:
* `rpc: use private broadcast from sendrawtransaction RPC if -privatebroadcast is ON`
* New tests:
* `test: add functional test for private broadcast`
* `test: add unit test for the private broadcast storage`
</details>
---
**This PR would resolve the following issues:**
https://github.com/bitcoin/bitcoin/issues/3828 Clients leak IPs if they are recipients of a transaction
https://github.com/bitcoin/bitcoin/issues/14692 Can't configure bitocoind to only send tx via Tor but receive clearnet transactions
https://github.com/bitcoin/bitcoin/issues/19042 Tor-only transaction broadcast onlynet=onion alternative
https://github.com/bitcoin/bitcoin/issues/24557 Option for receive events with all networks, but send transactions and/or blocks only with anonymous network[s]?
https://github.com/bitcoin/bitcoin/issues/25450 Ability to broadcast wallet transactions only via dedicated oneshot Tor connections
https://github.com/bitcoin/bitcoin/issues/32235 Tor: TX circuit isolation
**Issues that are related, but (maybe?) not to be resolved by this PR:**
https://github.com/bitcoin/bitcoin/issues/21876 Broadcast a transaction to specific nodes
https://github.com/bitcoin/bitcoin/issues/28636 new RPC: sendrawtransactiontopeer
---
Further extensions:
* Have the wallet do the private broadcast as well, https://github.com/bitcoin/bitcoin/issues/11887 would have to be resolved.
* Have the `submitpackage` RPC do the private broadcast as well, [draft diff in the comment below](https://github.com/bitcoin/bitcoin/pull/29415#pullrequestreview-2972293733), thanks ismaelsadeeq!
* Add some stats via RPC, so that the user can better monitor what is going on during and after the broadcast. Currently this can be done via the debug log, but that is not convenient.
* Make the private broadcast storage, currently in peerman, persistent over node restarts.
* Add (optional) random delay before starting to broadcast the transaction in order to avoid correlating unrelated transactions based on the time when they were broadcast. Suggested independently of this PR [here](https://github.com/bitcoin/bitcoin/issues/30471).
* Consider periodically sending transactions that did not originate from the node as decoy, discussed [here](https://github.com/bitcoin/bitcoin/pull/29415#discussion_r2035414972).
* Consider waiting for peer's FEEFILTER message and if the transaction that was sent to the peer is below that threshold, then assume the peer is going to drop it. Then use this knowledge to retry more aggressively with another peer, instead of the current 10 min. See [comment below](https://github.com/bitcoin/bitcoin/pull/29415#issuecomment-3258611648).
* It may make sense to be able to override the default policy -- eg so submitrawtransaction can go straight to the mempool and relay, even if txs are normally privately relayed. See [comment below](https://github.com/bitcoin/bitcoin/pull/29415#issuecomment-3427086681).
* As a side effect we have a new metric available - the time it takes for a transaction to reach a random node in the network (from the point of view of the private broadcast recipient the tx originator is a random node somewhere in the network). This can be useful for monitoring, unrelated to privacy characteristics of this feature.
---
_A previous incarnation of this can be found at https://github.com/bitcoin/bitcoin/pull/27509. It puts the transaction in the mempool and (tries to) hide it from the outside observers. This turned out to be too error prone or maybe even impossible._
ACKs for top commit:
l0rinc:
code review diff ACK 89372213048adf37a47427112a1ff836ee84c50e
andrewtoth:
ACK 89372213048adf37a47427112a1ff836ee84c50e
pinheadmz:
ACK 89372213048adf37a47427112a1ff836ee84c50e
w0xlt:
ACK 8937221304 with nit https://github.com/bitcoin/bitcoin/pull/29415#discussion_r2654849875
mzumsande:
re-ACK 89372213048adf37a47427112a1ff836ee84c50e
Tree-SHA512: d51dadc865c2eb080c903cbe2f669e69a967e5f9fc64e9a20a68f39a67bf0db6ac2ad682af7fa24ef9f0942a41c89959341a16ba7b616475e1c5ab8e563b9b96
Bitcoin Core
Setup
Bitcoin Core is the original Bitcoin client and it builds the backbone of the network. It downloads and, by default, stores the entire history of Bitcoin transactions, which requires several hundred gigabytes or more of disk space. Depending on the speed of your computer and network connection, the synchronization process can take anywhere from a few hours to several days or more.
To download Bitcoin Core, visit bitcoincore.org.
Running
The following are some helpful notes on how to run Bitcoin Core on your native platform.
Unix
Unpack the files into a directory and run:
bin/bitcoin-qt(GUI) orbin/bitcoind(headless)bin/bitcoin(wrapper command)
The bitcoin command supports subcommands like bitcoin gui, bitcoin node, and bitcoin rpc exposing different functionality. Subcommands can be listed with bitcoin help.
Windows
Unpack the files into a directory, and then run bitcoin-qt.exe.
macOS
Drag Bitcoin Core to your applications folder, and then run Bitcoin Core.
Need Help?
- See the documentation at the Bitcoin Wiki for help and more information.
- Ask for help on Bitcoin StackExchange.
- Ask for help on #bitcoin on Libera Chat. If you don't have an IRC client, you can use web.libera.chat.
- Ask for help on the BitcoinTalk forums, in the Technical Support board.
Building
The following are developer notes on how to build Bitcoin Core on your native platform. They are not complete guides, but include notes on the necessary libraries, compile flags, etc.
- Dependencies
- macOS Build Notes
- Unix Build Notes
- Windows Build Notes
- FreeBSD Build Notes
- OpenBSD Build Notes
- NetBSD Build Notes
Development
The Bitcoin repo's root README contains relevant information on the development process and automated testing.
- Developer Notes
- Productivity Notes
- Release Process
- Source Code Documentation (External Link)
- Translation Process
- Translation Strings Policy
- JSON-RPC Interface
- Unauthenticated REST Interface
- BIPS
- Dnsseed Policy
- Benchmarking
- Internal Design Docs
Resources
- Discuss on the BitcoinTalk forums, in the Development & Technical Discussion board.
- Discuss project-specific development on #bitcoin-core-dev on Libera Chat. If you don't have an IRC client, you can use web.libera.chat.
Miscellaneous
- Assets Attribution
- bitcoin.conf Configuration File
- CJDNS Support
- Files
- Fuzz-testing
- I2P Support
- Init Scripts (systemd/upstart/openrc)
- Managing Wallets
- Multisig Tutorial
- Offline Signing Tutorial
- P2P bad ports definition and list
- PSBT support
- Reduce Memory
- Reduce Traffic
- Tor Support
- Transaction Relay Policy
- ZMQ
License
Distributed under the MIT software license.