Merge bitcoin/bitcoin#22112: Force port 0 in I2P

4101ec9d2e doc: mention that we enforce port=0 in I2P (Vasil Dimov)
e0a2b390c1 addrman: reset I2P ports to 0 when loading from disk (Vasil Dimov)
41cda9d075 test: ensure I2P ports are handled as expected (Vasil Dimov)
4f432bd738 net: do not connect to I2P hosts on port!=0 (Vasil Dimov)
1f096f091e net: distinguish default port per network (Vasil Dimov)
aeac3bce3e net: change I2P seeds' ports to 0 (Vasil Dimov)
38f900290c net: change assumed I2P port to 0 (Vasil Dimov)

Pull request description:

  _This is an alternative to https://github.com/bitcoin/bitcoin/pull/21514, inspired by https://github.com/bitcoin/bitcoin/pull/21514#issuecomment-815049933. They are mutually exclusive. Just one of them should be merged._

  Change assumed ports for I2P to 0 (instead of the default 8333) as this is closer to what actually happens underneath with SAM 3.1 (https://github.com/bitcoin/bitcoin/pull/21514#issuecomment-812632520, https://github.com/bitcoin/bitcoin/pull/21514#issuecomment-816564719).

  Don't connect to I2P peers with advertised port != 0 (we don't specify a port to our SAM 3.1 proxy and it always connects to port = 0).

  Note, this change:
  * Keeps I2P addresses with port != 0 in addrman and relays them to others via P2P gossip. There may be non-bitcoin-core-22.0 peers using SAM 3.2 and for them such addresses may be useful.
  * Silently refuses to connect to I2P hosts with port != 0. This is ok for automatically chosen peers from addrman. Not so ok for peers provided via `-addnode` or `-connect` - a user who specifies `foo.b32.i2p:1234` (non zero port) may wonder why "nothing is happening".

  Fixes #21389

ACKs for top commit:
  laanwj:
    Code review ACK 4101ec9d2e
  jonatack:
    re-ACK 4101ec9d2e per `git range-diff efff9c3 0b0ee03 4101ec9`, built with DDEBUG_ADDRMAN, did fairly extensive testing on mainnet both with and without a peers.dat / -dnsseeds=0 to test boostrapping.

Tree-SHA512: 0e3c019e1dc05e54f559275859d3450e0c735596d179e30b66811aad9d5b5fabe3dcc44571e8f7b99f9fe16453eee393d6e153454dd873b9ff14907d4e6354fe
This commit is contained in:
W. J. van der Laan
2021-07-13 14:19:19 +02:00
13 changed files with 329 additions and 22 deletions

View File

@@ -70,3 +70,18 @@ RPC.
Bitcoin Core uses the [SAM v3.1](https://geti2p.net/en/docs/api/samv3) protocol
to connect to the I2P network. Any I2P router that supports it can be used.
## Ports in I2P and Bitcoin Core
Bitcoin Core uses the [SAM v3.1](https://geti2p.net/en/docs/api/samv3)
protocol. One particularity of SAM v3.1 is that it does not support ports,
unlike newer versions of SAM (v3.2 and up) that do support them and default the
port numbers to 0. From the point of view of peers that use newer versions of
SAM or other protocols that support ports, a SAM v3.1 peer is connecting to them
on port 0, from source port 0.
To allow future upgrades to newer versions of SAM, Bitcoin Core sets its
listening port to 0 when listening for incoming I2P connections and advertises
its own I2P address with port 0. Furthermore, it will not attempt to connect to
I2P addresses with a non-zero port number because with SAM v3.1 the destination
port (`TO_PORT`) is always set to 0 and is not in the control of Bitcoin Core.