feat(p2p): Seed connectivity tuning options: max-incoming-connection-time, incoming-connection-window

[lklimek]

Issue being fixed or feature implemented

Clients connecting to seed nodes never disconnect, causing seed to reject new clients due to lack of "free slots".

What was done?

1. Added configuration option max-incoming-connection-time that will drop incoming connections from non-persistent peers after configured time.
2. Exposed incoming-connection-window setting in config, to allow blocking immediate reconnect attempts

These settings, together with max-outgoing-connections, max-connections and persistent-peers, makes it possible to create seed node configuration that will disconnect clients from seed once it retrieves initial peer list.

Configuration of seed nodes

Suggested configuration of a seed node is as follows:

1. Set some trusted peers as persistent-peers (for example, 5 persistent peers) (optional)
2. Set max-outgoing-connections to a number slightly bigger than num of persistent peers (for example, 10)
3. Set max-connections to some value much larger than max-outgoing-connections (example: 50)
4. Set max-incoming-connection-time to a few seconds (example: "20s")
5. Set incoming-connection-window to a few minutes (example: "1m")

Note: numbers above require tuning on the actual network, they are just some kind of guess

How Has This Been Tested?

E2E

Using e2e framework, created a network of 20 nodes, and configured seed with the following settings:

• persistent_peers = ["validator01"]
• p2p_max_connections = 4
• p2p_max_outgoing_connections = 2
• p2p_max_incoming_connection_time = "5s"
• p2p_incoming_connection_window = "10s"

The network started successfully.

DevNet

Devnet test scenario

Configuration of seed node

In section [p2p], set the following settings:

max-outgoing-connections = 2
max-connections = 4
max-incoming-connection-time = "10s"
incoming-connection-window = "30s"

Expected behavior

Once the network is provisioned, nodes should very slowly join the network, with performance of ~4 nodes per minute.
This should be monitored; it is expected that all nodes will join the network in approx. 15-20 minutes.

Once all nodes join the network, the seed should maintain 2 outgoing connections, and 0-2 incoming connections (this can be monitored with netstat inside the container). Incoming connections should be disconnected after 30 seconds.

Breaking Changes

None

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone

[shotonoff]

LGMT. please have a look at the comments

[shotonoff]

PR looks good to me

[shotonoff]

🚀