[libp2p-dns] Implement /dnsaddr resolution.
#1931
Conversation
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It looks like looking up TXT records from |
This seems odd to me. Any suspicion why that might be the case? As a data point, though I doubt a very helpful one, the |
I don't know yet. I may have to do some noisy debugging on this branch for CI, for which I apologise in advance. |
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I changed the tests to be explicit about the name server(s) to use (quad9 in this case). Besides solving the problem with the request timeouts for TXT lookups with the system configuration, I think it is better to avoid the indirection via the opaque system configuration for the tests. |
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Still waiting on #1927. |
To that end, since resolving `/dnsaddr` addresses needs "fully qualified" multiaddresses when dialing, i.e. those that end with the `/p2p/...` protocol, we make sure that dialing always uses such fully qualified addresses by appending the `/p2p` protocol as necessary. As a side-effect, this adds support for dialing peers via "fully qualified" addresses, as an alternative to using a `PeerId` together with a `Multiaddr` with or without the `/p2p` protocol.
| })) => { | ||
| return Poll::Ready(Some(Ok(ListenerEvent::Upgrade { | ||
| upgrade: RelayedListenerUpgrade::Relayed(Some(stream)), | ||
| local_addr: relay_addr | ||
| .with(Protocol::P2p(relay_peer_id.into())) |
Closes #1920, as well as, by necessity, #1462.
This PR is based on #1927 - a proper diff until that PR is merged can be seen here.
In order to correctly resolve
/dnsaddraddresses, the DNS transport needs to be given "fully qualified" multiaddresses when dialing, i.e. those that end with the/p2p/...protocol, since it chooses from the TXT records such addresses with a matching suffix of the address being dialed. So to pick the addresses for the correct peer, the/p2pprotocol needs to be at the end of the address being dialed. This essentially goes back to #1462. So to address #1462 as well as implement/dnsaddrresolution, we now make sure that dialing always uses such fully qualified addresses by appending the/p2pprotocol as necessary in theNetworkoflibp2p-corebefore giving the address for dialing to the transport. This is mostly transparent for thePeerId-based APIs, i.e. it is of course still possible to use aPeerIdtogether with an "unqualified" address for dialing. It is just that at the end of the day,Transport::dial()always gets a fully-qualified address (when called from theNetworkanyway) and hence transports now permit a trailing/p2psuffix (and in the case of the DNS transport, even make essential use of it).As a side-effect,
Network::dial(addr)andSwarm::dial_addr(addr)now also handle "fully-qualified"/p2paddresses, since theNetworkwill then take the peer ID from the end of the address.A related change as part of implementing
/dnsaddrresolution is thatlibp2p-dnsnow actually tries to use all resolved addresses (well, up to a fixed maximum of dialing attempts).The net result of these changes can be seen in the now cleaned up
ipfs-kadexample, which can finally make use of/dnsaddr/bootstrap.libp2p.io.