net: add connect() and getsockopt() wrappers to Sock

Extend the `Sock` class with wrappers to `connect()` and `getsockopt()`.

This will make it possible to mock code which uses those.

Author: vasild

src/test/fuzz/util.h

@@ -685,6 +685,47 @@ class FuzzedSock : public Sock
         return random_bytes.size();
     }
 
+    int Connect(const sockaddr*, socklen_t) const override
+    {
+        // Have a permanent error at connect_errnos[0] because when the fuzzed data is exhausted
+        // SetFuzzedErrNo() will always return the first element and we want to avoid Connect()
+        // returning -1 and setting errno to EAGAIN repeatedly.
+        constexpr std::array connect_errnos{
+            ECONNREFUSED,
+            EAGAIN,
+            ECONNRESET,
+            EHOSTUNREACH,
+            EINPROGRESS,
+            EINTR,
+            ENETUNREACH,
+            ETIMEDOUT,
+        };
+        if (m_fuzzed_data_provider.ConsumeBool()) {
+            SetFuzzedErrNo(m_fuzzed_data_provider, connect_errnos);
+            return -1;
+        }
+        return 0;
+    }
+
+    int GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const override
+    {
+        constexpr std::array getsockopt_errnos{
+            ENOMEM,
+            ENOBUFS,
+        };
+        if (m_fuzzed_data_provider.ConsumeBool()) {
+            SetFuzzedErrNo(m_fuzzed_data_provider, getsockopt_errnos);
+            return -1;
+        }
+        if (opt_val == nullptr) {
+            return 0;
+        }
+        std::memcpy(opt_val,
+                    ConsumeFixedLengthByteVector(m_fuzzed_data_provider, *opt_len).data(),
+                    *opt_len);
+        return 0;
+    }
+
     bool Wait(std::chrono::milliseconds timeout, Event requested, Event* occurred = nullptr) const override
     {
         return m_fuzzed_data_provider.ConsumeBool();

src/util/sock.cpp

@@ -66,6 +66,16 @@ ssize_t Sock::Recv(void* buf, size_t len, int flags) const
     return recv(m_socket, static_cast<char*>(buf), len, flags);
 }
 
+int Sock::Connect(const sockaddr* addr, socklen_t addr_len) const
+{
+    return connect(m_socket, addr, addr_len);
+}
+
+int Sock::GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const
+{
+    return getsockopt(m_socket, level, opt_name, static_cast<char*>(opt_val), opt_len);
+}
+
 bool Sock::Wait(std::chrono::milliseconds timeout, Event requested, Event* occurred) const
 {
 #ifdef USE_POLL

src/util/sock.h

@@ -80,16 +80,29 @@ class Sock
 
     /**
      * send(2) wrapper. Equivalent to `send(this->Get(), data, len, flags);`. Code that uses this
-     * wrapper can be unit-tested if this method is overridden by a mock Sock implementation.
+     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     virtual ssize_t Send(const void* data, size_t len, int flags) const;
 
     /**
      * recv(2) wrapper. Equivalent to `recv(this->Get(), buf, len, flags);`. Code that uses this
-     * wrapper can be unit-tested if this method is overridden by a mock Sock implementation.
+     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
      */
     virtual ssize_t Recv(void* buf, size_t len, int flags) const;
 
+    /**
+     * connect(2) wrapper. Equivalent to `connect(this->Get(), addr, addrlen)`. Code that uses this
+     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
+     */
+    virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
+
+    /**
+     * getsockopt(2) wrapper. Equivalent to
+     * `getsockopt(this->Get(), level, opt_name, opt_val, opt_len)`. Code that uses this
+     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
+     */
+    virtual int GetSockOpt(int level, int opt_name, void* opt_val, socklen_t* opt_len) const;
+
     using Event = uint8_t;
 
     /**