set point-to-point mode on TAP

vendor/libtuntap-master/tuntap-windows.c

@@ -372,6 +372,7 @@ int
 tuntap_sys_set_ipv4(struct device *dev, t_tun_in_addr *s, uint32_t mask)
 {
   IPADDR sock[3];
+  IPADDR pp[2];
   DWORD len, ret;
   IPADDR ep[4];
 #pragma pack(push)
@@ -396,6 +397,18 @@ tuntap_sys_set_ipv4(struct device *dev, t_tun_in_addr *s, uint32_t mask)
     return -1;
   }
 
+  pp[0] = s->S_un.S_addr;
+  pp[1] = mask;
+
+  ret = DeviceIoControl(dev->tun_fd, TAP_IOCTL_CONFIG_POINT_TO_POINT, &pp, sizeof(pp),
+                        &pp, sizeof(pp), &len, NULL);
+  if(!ret)
+  {
+    int errcode = GetLastError();
+    tuntap_log(TUNTAP_LOG_ERR, (const char *)formated_error(L"%1%0", errcode));
+    return -1;
+  }
+
   ep[0] = s->S_un.S_addr;
   ep[1] = mask;
   ep[2] = (s->S_un.S_addr | ~mask)