Merge bitcoin/bitcoin#24378: refactor: make bind() and listen() mockable/testable

b2733ab6a85b234a88b83bdc77a0d043e18385b3 net: add new method Sock::Listen() that wraps listen() (Vasil Dimov)
3ad7de225efce3e76530f56bee8a8f7a75ea0f3c net: add new method Sock::Bind() that wraps bind() (Vasil Dimov)

Pull request description:

  _This is a piece of #21878, chopped off to ease review._

  Add new methods `Sock::Bind()` and `Sock::Listen()` that wrap `bind()` and `listen()`.
  This will help to increase `Sock` usage and make more code mockable.

ACKs for top commit:
  pk-b2:
    ACK b2733ab6a85b234a88b83bdc77a0d043e18385b3
  laanwj:
    Code review ACK b2733ab6a85b234a88b83bdc77a0d043e18385b3

Tree-SHA512: c6e737606703e2106fe60cc000cfbbae3a7f43deadb25f70531e2cac0457e0b0581440279d14c76c492eb85c12af4adde52c30baf74542c41597e419817488e8

1 files changed, 39 insertions, 0 deletions

diff --git a/src/test/fuzz/util.cpp b/src/test/fuzz/util.cpp
index c6bfcab327..4b893c648e 100644
--- a/src/test/fuzz/util.cpp
+++ b/src/test/fuzz/util.cpp
@@ -155,6 +155,45 @@ int FuzzedSock::Connect(const sockaddr*, socklen_t) const
     return 0;
 }
 
+int FuzzedSock::Bind(const sockaddr*, socklen_t) const
+{
+    // Have a permanent error at bind_errnos[0] because when the fuzzed data is exhausted
+    // SetFuzzedErrNo() will always set the global errno to bind_errnos[0]. We want to
+    // avoid this method returning -1 and setting errno to a temporary error (like EAGAIN)
+    // repeatedly because proper code should retry on temporary errors, leading to an
+    // infinite loop.
+    constexpr std::array bind_errnos{
+        EACCES,
+        EADDRINUSE,
+        EADDRNOTAVAIL,
+        EAGAIN,
+    };
+    if (m_fuzzed_data_provider.ConsumeBool()) {
+        SetFuzzedErrNo(m_fuzzed_data_provider, bind_errnos);
+        return -1;
+    }
+    return 0;
+}
+
+int FuzzedSock::Listen(int) const
+{
+    // Have a permanent error at listen_errnos[0] because when the fuzzed data is exhausted
+    // SetFuzzedErrNo() will always set the global errno to listen_errnos[0]. We want to
+    // avoid this method returning -1 and setting errno to a temporary error (like EAGAIN)
+    // repeatedly because proper code should retry on temporary errors, leading to an
+    // infinite loop.
+    constexpr std::array listen_errnos{
+        EADDRINUSE,
+        EINVAL,
+        EOPNOTSUPP,
+    };
+    if (m_fuzzed_data_provider.ConsumeBool()) {
+        SetFuzzedErrNo(m_fuzzed_data_provider, listen_errnos);
+        return -1;
+    }
+    return 0;
+}
+
 std::unique_ptr<Sock> FuzzedSock::Accept(sockaddr* addr, socklen_t* addr_len) const
 {
     constexpr std::array accept_errnos{