#24545 bip324-enable

[dhruv]

This PR brings together all other BIP324 PRs and enables v2 encrypted P2P transport.

Builds on top of open PRs: #25354, #25361, #23233, #23561, #23432. It looks like there's a lot of commits, but only the last 10 commits belong in this PR. The rest will be merged with upstream PRs.

Running a v2 node

Get the code

git remote add bip324 [email protected]:dhruv/bitcoin.git
git fetch bip324
git checkout bip324/bip324-enable

Build for your OS

Follow the appropriate instructions here

Run the node

src/bitcoind -conf=CONFIG_FILE -v2transport=1

Connect with a friend's v2 node

src/bitcoin-cli -conf=CONFIG_FILE addnode "FRIEND_IP:FRIEND_PORT" "add" true

The last parameter(p2p_v2:true) signals to your node that the peer is running a v2 supportive client and we should attempt to make an encrypted P2P connection (you're simulating the NODE_P2P_V2 service flag advertisement manually). Should that fail however (say because the peer told you mistakenly, lied, etc.), this code will downgrade the connection to unencrypted v1 transport.

Things you are helpful to test

• If your friend's node is a v2 node, you can see with wireshark that the bytes are pseudorandom (the easiest way to confirm this is that with a v1 connection, wireshark will tell you it has detected a Bitcoin connection and it'll even parse out the metadata like message type, etc; with v2, wireshark has no idea -- of course that could be because wireshark does simply not know v2, but it is because the bytestream is pseudorandom)
• Add another peer that is actually v1, but try addnode still indicating v2 support. You should see with wireshark that after a failed attempt at a v2 handshake, the connection is downgraded to unencrypted v1 and wireshark can parse it.

I've been told there are v2 nodes running at (happy to update the list as more people run persistent v2 nodes; message me and I'll add it here):

jdcoysubtxazi7dketpyb5rnjorvxad4onftveohash2pdwkgw4bvnqd.onion
rp7k2go3s5lyj3fnj6zn62ktarlrsft2ohlsxkyd7v3e3idqyptvread.onion:8333

I have unit tested whatever made sense to me. The regression tests are WIP and @ stratospher will be opening that PR soon.

PS: I know it's a little frustrating that the BIP text itself is not released yet. We're working on it and we're close. I appreciate the patience.