How peer discovery works after connecting to hardcoded nodes?

Question

I am tinkering with the bitcoin source code and trying to understand the exact working of peer discovery mechanism in the testnet mode for which I have made the following changes:

1. Disabled the DNS seed discovery in order to force bitcoind to fallback to connect to hardcoded nodes.

2. Changed the default hardcoded nodes to my known 4 addresses, lets say A,B,C and D, which I ensure are always online.

Now, when I run the bitcoind client (call it E), it connects to one of A,B,C or D, running the same modified version of bitcoind. It gets the peer addresses from the hardcoded node that it first connects to by exchanging getaddr and addr messages but I am not sure how it proceeds after that. I have following queries:

a. If a node falls back to connect to hardcoded nodes, is it supposed to connect to only one of the hardcoded nodes like it happends in my case or can it connect to multiple hardcoded nodes ?

b. After getting peer address via the addr message, when will the node E start connecting to those peers ?

Please point me to the relevant code files/sections if possible. Thanks

Answer 1

Did you add the hardcoded nodes with addnode or with connect?

addnode=<ip> Add a node to connect to and attempt to keep the connection open
connect=<ip> Connect only to the specified node(s)

So, if you used connect, it will not connect to any but the hardcoded nodes.