Merge bitcoin/bitcoin#28423: kernel: Remove protocol.h/netaddress.h/compat.h from kernel headers

d506765199 [refactor] Remove compat.h from kernel headers (TheCharlatan)
36193af47c [refactor] Remove netaddress.h from kernel headers (TheCharlatan)
2b08c55f01 [refactor] Add CChainParams member to CConnman (TheCharlatan)
f0d1d8b35c [refactor] Add missing includes for next commit (TheCharlatan)
534b314a74 kernel: Move MessageStartChars to its own file (TheCharlatan)
9be330b654 [refactor] Define MessageStartChars as std::array (TheCharlatan)
37e2b01113 [refactor] Allow std::array<std::byte, N> in serialize.h (MarcoFalke)

Pull request description:

  This removes the non-consensus critical `protocol.h` and `netaddress.h` headers from the kernel headers. With this patch, they are no longer required to include in order to use the libbitcoinkernel library. This also allows for the removal of the `compat.h` header from the kernel headers.

  As an added future benefit it also reduces the number of of kernel headers that include the platform specific `bitcoin-config.h`.

  For those interested, the currently required kernel headers can be inspected visually with the [sourcetrail](https://github.com/CoatiSoftware/Sourcetrail) tool by looking at the required includes of `bitcoin-chainstate.cpp`.

  ---

  This is part of the [libbitcoinkernel project](https://github.com/bitcoin/bitcoin/issues/27587), namely its stage 1 step 3: Decouple most non-consensus headers from libbitcoinkernel.

ACKs for top commit:
  stickies-v:
    re-ACK d506765
  hebasto:
    ACK d506765199.
  ajtowns:
    utACK d506765199
  MarcoFalke:
    lgtm ACK d506765199 🍛

Tree-SHA512: 6f90ea510a302c2927e84d16900e89997c39b8ff3ce9d4effeb8a134bd29cc52bd9e81e51aaa11f7496bad00025b78a58b88c5a9e0bb3f4ebbe9a76309215fb7

src/kernel/chainparams.cpp

@@ -10,6 +10,7 @@
 #include <consensus/merkle.h>
 #include <consensus/params.h>
 #include <hash.h>
+#include <kernel/messagestartchars.h>
 #include <logging.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
@@ -359,7 +360,7 @@ public:
         HashWriter h{};
         h << consensus.signet_challenge;
         uint256 hash = h.GetHash();
-        memcpy(pchMessageStart, hash.begin(), 4);
+        std::copy_n(hash.begin(), 4, pchMessageStart.begin());
 
         nDefaultPort = 38333;
         nPruneAfterHeight = 1000;

src/kernel/chainparams.h

@@ -7,9 +7,8 @@
 #define BITCOIN_KERNEL_CHAINPARAMS_H
 
 #include <consensus/params.h>
-#include <netaddress.h>
+#include <kernel/messagestartchars.h>
 #include <primitives/block.h>
-#include <protocol.h>
 #include <uint256.h>
 #include <util/chaintype.h>
 #include <util/hash_type.h>
@@ -87,17 +86,8 @@ public:
     };
 
     const Consensus::Params& GetConsensus() const { return consensus; }
-    const CMessageHeader::MessageStartChars& MessageStart() const { return pchMessageStart; }
+    const MessageStartChars& MessageStart() const { return pchMessageStart; }
     uint16_t GetDefaultPort() const { return nDefaultPort; }
-    uint16_t GetDefaultPort(Network net) const
-    {
-        return net == NET_I2P ? I2P_SAM31_PORT : GetDefaultPort();
-    }
-    uint16_t GetDefaultPort(const std::string& addr) const
-    {
-        CNetAddr a;
-        return a.SetSpecial(addr) ? GetDefaultPort(a.GetNetwork()) : GetDefaultPort();
-    }
 
     const CBlock& GenesisBlock() const { return genesis; }
     /** Default value for -checkmempool and -checkblockindex argument */
@@ -165,7 +155,7 @@ protected:
     CChainParams() {}
 
     Consensus::Params consensus;
-    CMessageHeader::MessageStartChars pchMessageStart;
+    MessageStartChars pchMessageStart;
     uint16_t nDefaultPort;
     uint64_t nPruneAfterHeight;
     uint64_t m_assumed_blockchain_size;

src/kernel/messagestartchars.h

@@ -0,0 +1,13 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KERNEL_MESSAGESTARTCHARS_H
+#define BITCOIN_KERNEL_MESSAGESTARTCHARS_H
+
+#include <array>
+#include <cstdint>
+
+using MessageStartChars = std::array<uint8_t, 4>;
+
+#endif // BITCOIN_KERNEL_MESSAGESTARTCHARS_H