Problem: on a failure to setsockopt SO_BINDTODEVICE, libzmq asserts

Solution: return an error to the user instead

src/ip.cpp

@@ -227,20 +227,31 @@ int zmq::set_nosigpipe (fd_t s_)
     return 0;
 }
 
-void zmq::bind_to_device (fd_t s_, const std::string &bound_device_)
+int zmq::bind_to_device (fd_t s_, const std::string &bound_device_)
 {
 #ifdef ZMQ_HAVE_SO_BINDTODEVICE
     int rc = setsockopt (s_, SOL_SOCKET, SO_BINDTODEVICE,
                          bound_device_.c_str (), bound_device_.length ());
 
 #ifdef ZMQ_HAVE_WINDOWS
-    wsa_assert (rc != SOCKET_ERROR);
+    if (rc != SOCKET_ERROR)
+        return 0;
+    const int lastError = WSAGetLastError ();
+    errno = wsa_error_to_errno (lastError);
+    wsa_assert (lastError != WSAENOTSOCK);
+    return -1;
 #else
-    errno_assert (rc == 0);
+    if (rc == 0)
+        return 0;
+    errno_assert (errno != ENOTSOCK);
+    return -1;
 #endif
 #else
     LIBZMQ_UNUSED (s_);
     LIBZMQ_UNUSED (bound_device_);
+
+    errno = ENOTSUP;
+    return -1;
 #endif
 }
 

src/ip.hpp

@@ -56,7 +56,7 @@ void set_ip_type_of_service (fd_t s_, int iptos_);
 int set_nosigpipe (fd_t s_);
 
 // Binds the underlying socket to the given device, eg. VRF or interface
-void bind_to_device (fd_t s_, const std::string &bound_device_);
+int bind_to_device (fd_t s_, const std::string &bound_device_);
 
 // Initialize network subsystem. May be called multiple times. Each call must be matched by a call to shutdown_network.
 bool initialize_network ();

src/tcp.cpp

@@ -40,6 +40,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <unistd.h>
 #ifdef ZMQ_HAVE_VXWORKS
 #include <sockLib.h>
 #endif
@@ -427,7 +428,8 @@ zmq::fd_t zmq::tcp_open_socket (const char *address_,
 
     // Bind the socket to a device if applicable
     if (!options_.bound_device.empty ())
-        bind_to_device (s, options_.bound_device);
+        if (bind_to_device (s, options_.bound_device) == -1)
+            goto setsockopt_error;
 
     //  Set the socket buffer limits for the underlying socket.
     if (options_.sndbuf >= 0)
@@ -436,4 +438,14 @@ zmq::fd_t zmq::tcp_open_socket (const char *address_,
         set_tcp_receive_buffer (s, options_.rcvbuf);
 
     return s;
+
+setsockopt_error:
+#ifdef ZMQ_HAVE_WINDOWS
+    rc = closesocket (s);
+    wsa_assert (rc != SOCKET_ERROR);
+#else
+    rc = ::close (s);
+    errno_assert (rc == 0);
+#endif
+    return retired_fd;
 }