IBC#022: Bitcoin Core Initialization, Step 7— Peer Manager

Peer manager initialization

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Last episode was focused on cache memory allocation. Today we are going to continue our trip inside the initialization of Bitcoin Core finishing Step 7. [Code Link]

Let’s start!

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User Shutdown Request

After launching loading of the chain state, the code check whether or not the user closes the process manually. A user could request to shutdown the node due to the fact that the LoadBlockIndex() function could take several minute to complete. In case of shutdown, the initialization function returns false.

    if (ShutdownRequested(node)) {
        LogInfo(”Shutdown requested. Exiting.”);
        return false;
    }

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Peer Manager Initialization

Once the previous step has been completed, the program continues with the initialization of the PeerManager object.

It first checks that ChainstateManager and KernelNotifications objects in the node are defined.

    ChainstateManager& chainman = *Assert(node.chainman);
    auto& kernel_notifications{*Assert(node.notifications)};

Then, it checks that the PeerManager object has not been initialized, yet.

    assert(!node.peerman);

If everything goes smoothly, the software initialized the PeerManager with the following inputs:

• Connection manager object CConnman: Manages connections to other nodes.

• Address manager object AddrMan: Stores addresses of other nodes and info about their reputations.

• Ban manager object BanMan: Manages banned peers.

• Chainstate manager object ChainstateManager: Validates blocks and transactions from other peers.

• Mempool object CTxMemPool: Manages mempool operations

• Warnings object node::Warnings: Handles the overall warning system.

• Peer manager options object PeerManager::Options: Configuration parameters.

    node.peerman = PeerManager::make(*node.connman, *node.addrman,
                                     node.banman.get(), chainman,
                                     *node.mempool, *node.warnings,
                                     peerman_opts);

Finally, the PeerManager object is registered to receive events generated in validation and mempool.

    validation_signals.RegisterValidationInterface(node.peerman.get());

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