netbase: refactor CreateSock() to accept sa_family_t

Also implement CService::GetSAFamily() to provide sa_family_t

src/compat/compat.h

@@ -32,6 +32,13 @@
 #include <unistd.h>      // IWYU pragma: export
 #endif
 
+// Windows does not have `sa_family_t` - it defines `sockaddr::sa_family` as `u_short`.
+// Thus define `sa_family_t` on Windows too so that the rest of the code can use `sa_family_t`.
+// See https://learn.microsoft.com/en-us/windows/win32/api/winsock/ns-winsock-sockaddr#syntax
+#ifdef WIN32
+typedef u_short sa_family_t;
+#endif
+
 // We map Linux / BSD error functions and codes, to the equivalent
 // Windows definitions, and use the WSA* names throughout our code.
 // Note that glibc defines EWOULDBLOCK as EAGAIN (see errno.h).

src/i2p.cpp

@@ -326,7 +326,7 @@ Session::Reply Session::SendRequestAndGetReply(const Sock& sock,
 
 std::unique_ptr<Sock> Session::Hello() const
 {
-    auto sock = CreateSock(m_control_host);
+    auto sock = CreateSock(m_control_host.GetSAFamily());
 
     if (!sock) {
         throw std::runtime_error("Cannot create socket");

src/net.cpp

@@ -483,15 +483,16 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
                 addr_bind = CAddress{conn.me, NODE_NONE};
             }
         } else if (use_proxy) {
-            sock = CreateSock(proxy.proxy);
+            sock = CreateSock(proxy.proxy.GetSAFamily());
             if (!sock) {
                 return nullptr;
             }
+            LogPrintLevel(BCLog::PROXY, BCLog::Level::Debug, "Using proxy: %s to connect to %s:%s\n", proxy.proxy.ToStringAddrPort(), addrConnect.ToStringAddr(), addrConnect.GetPort());
             connected = ConnectThroughProxy(proxy, addrConnect.ToStringAddr(), addrConnect.GetPort(),
                                             *sock, nConnectTimeout, proxyConnectionFailed);
         } else {
             // no proxy needed (none set for target network)
-            sock = CreateSock(addrConnect);
+            sock = CreateSock(addrConnect.GetSAFamily());
             if (!sock) {
                 return nullptr;
             }
@@ -504,7 +505,7 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
             addrman.Attempt(addrConnect, fCountFailure);
         }
     } else if (pszDest && GetNameProxy(proxy)) {
-        sock = CreateSock(proxy.proxy);
+        sock = CreateSock(proxy.proxy.GetSAFamily());
         if (!sock) {
             return nullptr;
         }
@@ -2993,7 +2994,7 @@ bool CConnman::BindListenPort(const CService& addrBind, bilingual_str& strError,
         return false;
     }
 
-    std::unique_ptr<Sock> sock = CreateSock(addrBind);
+    std::unique_ptr<Sock> sock = CreateSock(addrBind.GetSAFamily());
     if (!sock) {
         strError = strprintf(Untranslated("Couldn't open socket for incoming connections (socket returned error %s)"), NetworkErrorString(WSAGetLastError()));
         LogPrintLevel(BCLog::NET, BCLog::Level::Error, "%s\n", strError.original);

src/netaddress.cpp

@@ -818,6 +818,19 @@ bool CService::SetSockAddr(const struct sockaddr *paddr)
     }
 }
 
+sa_family_t CService::GetSAFamily() const
+{
+    switch (m_net) {
+    case NET_IPV4:
+        return AF_INET;
+    case NET_IPV6:
+    case NET_CJDNS:
+        return AF_INET6;
+    default:
+        return AF_UNSPEC;
+    }
+}
+
 uint16_t CService::GetPort() const
 {
     return port;

src/netaddress.h

@@ -540,6 +540,11 @@ public:
     uint16_t GetPort() const;
     bool GetSockAddr(struct sockaddr* paddr, socklen_t* addrlen) const;
     bool SetSockAddr(const struct sockaddr* paddr);
+    /**
+     * Get the address family
+     * @returns AF_UNSPEC if unspecified
+     */
+    [[nodiscard]] sa_family_t GetSAFamily() const;
     friend bool operator==(const CService& a, const CService& b);
     friend bool operator!=(const CService& a, const CService& b) { return !(a == b); }
     friend bool operator<(const CService& a, const CService& b);

src/netbase.cpp

@@ -444,18 +444,13 @@ bool Socks5(const std::string& strDest, uint16_t port, const ProxyCredentials* a
     }
 }
 
-std::unique_ptr<Sock> CreateSockTCP(const CService& address_family)
+std::unique_ptr<Sock> CreateSockOS(sa_family_t address_family)
 {
-    // Create a sockaddr from the specified service.
-    struct sockaddr_storage sockaddr;
-    socklen_t len = sizeof(sockaddr);
-    if (!address_family.GetSockAddr((struct sockaddr*)&sockaddr, &len)) {
-        LogPrintf("Cannot create socket for %s: unsupported network\n", address_family.ToStringAddrPort());
-        return nullptr;
-    }
+    // Not IPv4 or IPv6
+    if (address_family == AF_UNSPEC) return nullptr;
 
     // Create a TCP socket in the address family of the specified service.
-    SOCKET hSocket = socket(((struct sockaddr*)&sockaddr)->sa_family, SOCK_STREAM, IPPROTO_TCP);
+    SOCKET hSocket = socket(address_family, SOCK_STREAM, IPPROTO_TCP);
     if (hSocket == INVALID_SOCKET) {
         return nullptr;
     }
@@ -493,7 +488,7 @@ std::unique_ptr<Sock> CreateSockTCP(const CService& address_family)
     return sock;
 }
 
-std::function<std::unique_ptr<Sock>(const CService&)> CreateSock = CreateSockTCP;
+std::function<std::unique_ptr<Sock>(const sa_family_t&)> CreateSock = CreateSockOS;
 
 template<typename... Args>
 static void LogConnectFailure(bool manual_connection, const char* fmt, const Args&... args) {

src/netbase.h

@@ -229,16 +229,16 @@ CService LookupNumeric(const std::string& name, uint16_t portDefault = 0, DNSLoo
 CSubNet LookupSubNet(const std::string& subnet_str);
 
 /**
- * Create a TCP socket in the given address family.
- * @param[in] address_family The socket is created in the same address family as this address.
+ * Create a socket in the given address family.
+ * @param[in] address_family to use for the socket.
  * @return pointer to the created Sock object or unique_ptr that owns nothing in case of failure
  */
-std::unique_ptr<Sock> CreateSockTCP(const CService& address_family);
+std::unique_ptr<Sock> CreateSockOS(sa_family_t address_family);
 
 /**
- * Socket factory. Defaults to `CreateSockTCP()`, but can be overridden by unit tests.
+ * Socket factory. Defaults to `CreateSockOS()`, but can be overridden by unit tests.
  */
-extern std::function<std::unique_ptr<Sock>(const CService&)> CreateSock;
+extern std::function<std::unique_ptr<Sock>(const sa_family_t&)> CreateSock;
 
 /**
  * Try to connect to the specified service on the specified socket.

src/test/fuzz/fuzz.cpp

@@ -81,7 +81,7 @@ static const TypeTestOneInput* g_test_one_input{nullptr};
 void initialize()
 {
     // Terminate immediately if a fuzzing harness ever tries to create a TCP socket.
-    CreateSock = [](const CService&) -> std::unique_ptr<Sock> { std::terminate(); };
+    CreateSock = [](const sa_family_t&) -> std::unique_ptr<Sock> { std::terminate(); };
 
     // Terminate immediately if a fuzzing harness ever tries to perform a DNS lookup.
     g_dns_lookup = [](const std::string& name, bool allow_lookup) {

src/test/i2p_tests.cpp

@@ -38,7 +38,7 @@ public:
 
 private:
     const BCLog::Level m_prev_log_level;
-    const std::function<std::unique_ptr<Sock>(const CService&)> m_create_sock_orig;
+    const std::function<std::unique_ptr<Sock>(const sa_family_t&)> m_create_sock_orig;
 };
 
 BOOST_FIXTURE_TEST_SUITE(i2p_tests, EnvTestingSetup)
@@ -46,7 +46,7 @@ BOOST_FIXTURE_TEST_SUITE(i2p_tests, EnvTestingSetup)
 BOOST_AUTO_TEST_CASE(unlimited_recv)
 {
     // Mock CreateSock() to create MockSock.
-    CreateSock = [](const CService&) {
+    CreateSock = [](const sa_family_t&) {
         return std::make_unique<StaticContentsSock>(std::string(i2p::sam::MAX_MSG_SIZE + 1, 'a'));
     };
 
@@ -66,7 +66,7 @@ BOOST_AUTO_TEST_CASE(unlimited_recv)
 BOOST_AUTO_TEST_CASE(listen_ok_accept_fail)
 {
     size_t num_sockets{0};
-    CreateSock = [&num_sockets](const CService&) {
+    CreateSock = [&num_sockets](const sa_family_t&) {
         // clang-format off
         ++num_sockets;
         // First socket is the control socket for creating the session.
@@ -130,7 +130,7 @@ BOOST_AUTO_TEST_CASE(damaged_private_key)
 {
     const auto CreateSockOrig = CreateSock;
 
-    CreateSock = [](const CService&) {
+    CreateSock = [](const sa_family_t&) {
         return std::make_unique<StaticContentsSock>("HELLO REPLY RESULT=OK VERSION=3.1\n"
                                                     "SESSION STATUS RESULT=OK DESTINATION=\n");
     };