Add external_addr to config (network section)

[fanatid]

Motivation

Allow zebrad advertise address specified by user.

Solution

Add external_addr to config (network section).

• In the diagram, I see that listen port (address) should be in AddressBook but I can not find code where listen_addr added to AddressBook. Can you help with this?

  zebra/zebra-network/src/peer_set/candidate_set.rs

  Line 46 in 2cecd52

  /// │ │ Listener Port │ │

The code in this pull request has:

• Documentation Comments
• Unit Tests and Property Tests

Related Issues

#1890

Follow Up Work

Allow set only IP address in listen_addr (default port from Network enum).

zebra/zebra-network/src/peer_set/initialize.rs

Lines 127 to 128 in 2cecd52

	// TODO: use the right port if the port is unspecified
	// split the address and port configs?

[teor2345]

• In the diagram, I see that listen port (address) should be in AddressBook but I can not find code where listen_addr added to AddressBook. Can you help with this?

I think that diagram is a bit confusing, maybe we should say "Inbound Peer Connections to the zebrad listener port".

[teor2345]

• In the diagram, I see that listen port (address) should be in AddressBook but I can not find code where listen_addr added to AddressBook. Can you help with this?

I think that diagram is a bit confusing, maybe we should say "Inbound Peer Connections to the zebrad listener port".

#2036 might help here, I updated the docs.

[dconnolly]

Looks like rustfmt doesn't like the space on one line, causing rustfmt job to fail

[teor2345]

Can you turn this into an external_addr() method on Config?
(And make Config.external_addr private or pub(crate).)

That way, we'll always get the external address the right way.

(We'll also want to use the external address in #1892 and similar tickets.)

[teor2345]

I think we'll want to have separate IPv4 and IPv6 external addresses, and choose the external address based on the connection's IP version. (See #1890.)

We'll also want to:

• add the external address for the connection's IP version to Zebra's Version messages
• add both external addresses to Zebra's Peers responses
• fallback to the internal address if there is no external address

but that depends on #2033 merging:
https://github.com/ZcashFoundation/zebra/pull/2033/files#diff-3f14971a74a109913a4809bd1a77f4e0145e1edfa72aaded8f1fdcb2cc45f4f1R243-R244

As part of that change, we'll want to make the AddressBook ignore any null addresses (0.0.0.0 or [::]).

[teor2345]

I'm going to mark this PR as draft until the Zebra team decides which changes we actually need here.

[teor2345]

We might merge this as part of ticket #3117 when we get to it.