Merge bitcoin/bitcoin#31092: doc: fuzz: remove Honggfuzz NetDriver instructions

d823ba6e20 doc: fuzz: remove Honggfuzz NetDriver instructions (brunoerg)

Pull request description:

  Remove Honggfuzz NetDriver instructions from the documentation since it has not been useful for us. See https://github.com/bitcoin/bitcoin/issues/30957 and https://github.com/bitcoin/bitcoin/pull/31012.

ACKs for top commit:
  maflcko:
    lgtm ACK d823ba6e20
  marcofleon:
    ACK d823ba6e20

Tree-SHA512: f63fde1076d523dc5e511ef868ca3c1ea2e38fe7df56ae275f33209581f96452d86effedb54d9b0ee8b7a1d492b610799807a727d8bd81e2286d31db4aa68731

doc/fuzzing.md

@@ -206,82 +206,6 @@ $ FUZZ=process_message ./honggfuzz/honggfuzz -i inputs/ -- build_fuzz/src/test/f
 
 Read the [Honggfuzz documentation](https://github.com/google/honggfuzz/blob/master/docs/USAGE.md) for more information.
 
-## Fuzzing the Bitcoin Core P2P layer using Honggfuzz NetDriver
-
-Honggfuzz NetDriver allows for very easy fuzzing of TCP servers such as Bitcoin
-Core without having to write any custom fuzzing harness. The `bitcoind` server
-process is largely fuzzed without modification.
-
-This makes the fuzzing highly realistic: a bug reachable by the fuzzer is likely
-also remotely triggerable by an untrusted peer.
-
-To quickly get started fuzzing the P2P layer using Honggfuzz NetDriver:
-
-```sh
-$ mkdir bitcoin-honggfuzz-p2p/
-$ cd bitcoin-honggfuzz-p2p/
-$ git clone https://github.com/bitcoin/bitcoin
-$ cd bitcoin/
-$ git clone https://github.com/google/honggfuzz
-$ cd honggfuzz/
-$ make
-$ cd ..
-$ git apply << "EOF"
-diff --git a/src/compat/compat.h b/src/compat/compat.h
-index 8195bceaec..cce2b31ff0 100644
---- a/src/compat/compat.h
-+++ b/src/compat/compat.h
-@@ -90,8 +90,12 @@ typedef char* sockopt_arg_type;
- // building with a binutils < 2.36 is subject to this ld bug.
- #define MAIN_FUNCTION __declspec(dllexport) int main(int argc, char* argv[])
- #else
-+#ifdef HFND_FUZZING_ENTRY_FUNCTION_CXX
-+#define MAIN_FUNCTION HFND_FUZZING_ENTRY_FUNCTION_CXX(int argc, char* argv[])
-+#else
- #define MAIN_FUNCTION int main(int argc, char* argv[])
- #endif
-+#endif
-
- // Note these both should work with the current usage of poll, but best to be safe
- // WIN32 poll is broken https://daniel.haxx.se/blog/2012/10/10/wsapoll-is-broken/
-diff --git a/src/net.cpp b/src/net.cpp
-index 7601a6ea84..702d0f56ce 100644
---- a/src/net.cpp
-+++ b/src/net.cpp
-@@ -727,7 +727,7 @@ int V1TransportDeserializer::readHeader(Span<const uint8_t> msg_bytes)
-     }
-
-     // Check start string, network magic
--    if (memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) {
-+    if (false && memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) { // skip network magic checking
-         LogDebug(BCLog::NET, "Header error: Wrong MessageStart %s received, peer=%d\n", HexStr(hdr.pchMessageStart), m_node_id);
-         return -1;
-     }
-@@ -788,7 +788,7 @@ CNetMessage V1TransportDeserializer::GetMessage(const std::chrono::microseconds
-     RandAddEvent(ReadLE32(hash.begin()));
-
-     // Check checksum and header message type string
--    if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
-+    if (false && memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) { // skip checksum checking
-         LogDebug(BCLog::NET, "Header error: Wrong checksum (%s, %u bytes), expected %s was %s, peer=%d\n",
-                  SanitizeString(msg.m_type), msg.m_message_size,
-                  HexStr(Span{hash}.first(CMessageHeader::CHECKSUM_SIZE)),
-EOF
-$ cmake -B build_fuzz \
-   -DCMAKE_C_COMPILER="$(pwd)/honggfuzz/hfuzz_cc/hfuzz-clang" \
-   -DCMAKE_CXX_COMPILER="$(pwd)/honggfuzz/hfuzz_cc/hfuzz-clang++" \
-   -DENABLE_WALLET=OFF \
-   -DBUILD_GUI=OFF \
-   -DSANITIZERS=address,undefined
-$ cmake --build build_fuzz --target bitcoind
-$ mkdir -p inputs/
-$ ./honggfuzz/honggfuzz --exit_upon_crash --quiet --timeout 4 -n 1 -Q \
-      -E HFND_TCP_PORT=18444 -f inputs/ -- \
-          build_fuzz/src/bitcoind -regtest -discover=0 -dns=0 -dnsseed=0 -listenonion=0 \
-                       -nodebuglogfile -bind=127.0.0.1:18444 -logthreadnames \
-                       -debug
-```
-
 # OSS-Fuzz
 
 Bitcoin Core participates in Google's [OSS-Fuzz](https://github.com/google/oss-fuzz/tree/master/projects/bitcoin-core)