code.octet-stream.net Git - netwatcher/blob - src/watch_win.rs

   1 use std::ffi::c_void;
   2 use std::pin::Pin;
   3 use std::sync::Mutex;
   4
   5 use windows::Win32::Foundation::ERROR_INVALID_HANDLE;
   6 use windows::Win32::Foundation::ERROR_INVALID_PARAMETER;
   7 use windows::Win32::Foundation::ERROR_NOT_ENOUGH_MEMORY;
   8 use windows::Win32::Foundation::NO_ERROR;
   9 use windows::Win32::NetworkManagement::IpHelper::CancelMibChangeNotify2;
  10 use windows::Win32::NetworkManagement::IpHelper::MIB_NOTIFICATION_TYPE;
  11 use windows::Win32::NetworkManagement::IpHelper::MIB_UNICASTIPADDRESS_ROW;
  12 use windows::Win32::{
  13     Foundation::{BOOLEAN, HANDLE},
  14     NetworkManagement::IpHelper::NotifyUnicastIpAddressChange,
  15     Networking::WinSock::AF_UNSPEC,
  16 };
  17
  18 use crate::Error;
  19 use crate::List;
  20 use crate::Update;
  21
  22 struct WatchState {
  23     /// The last result that we captured, for diffing
  24     prev_list: List,
  25     /// User's callback
  26     cb: Box<dyn FnMut(Update) + Send + 'static>,
  27 }
  28
  29 pub(crate) struct WatchHandle {
  30     hnd: HANDLE,
  31     _state: Pin<Box<Mutex<WatchState>>>,
  32 }
  33
  34 impl Drop for WatchHandle {
  35     fn drop(&mut self) {
  36         unsafe {
  37             let _ = CancelMibChangeNotify2(self.hnd);
  38         }
  39     }
  40 }
  41
  42 pub(crate) fn watch_interfaces<F: FnMut(Update) + Send + 'static>(
  43     callback: F,
  44 ) -> Result<WatchHandle, Error> {
  45     let state = Box::pin(Mutex::new(WatchState {
  46         prev_list: List::default(),
  47         cb: Box::new(callback),
  48     }));
  49     let state_ctx = &*state.as_ref() as *const _ as *const c_void;
  50
  51     let mut hnd = HANDLE::default();
  52     let res = unsafe {
  53         NotifyUnicastIpAddressChange(
  54             AF_UNSPEC,
  55             Some(notif),
  56             Some(state_ctx),
  57             BOOLEAN(0),
  58             &mut hnd,
  59         )
  60     };
  61     match res {
  62         NO_ERROR => {
  63             // Trigger an initial update
  64             handle_notif(&mut state.lock().unwrap(), crate::list::list_interfaces()?);
  65             // Then return the handle
  66             Ok(WatchHandle { hnd, _state: state })
  67         }
  68         ERROR_INVALID_HANDLE => Err(Error::InvalidHandle),
  69         ERROR_INVALID_PARAMETER => Err(Error::InvalidParameter),
  70         ERROR_NOT_ENOUGH_MEMORY => Err(Error::NotEnoughMemory),
  71         _ => Err(Error::UnexpectedWindowsResult(res.0)),
  72     }
  73 }
  74
  75 unsafe extern "system" fn notif(
  76     ctx: *const c_void,
  77     _row: *const MIB_UNICASTIPADDRESS_ROW,
  78     _notification_type: MIB_NOTIFICATION_TYPE,
  79 ) {
  80     let state_ptr = ctx as *const Mutex<WatchState>;
  81     unsafe {
  82         let state_guard = &mut *state_ptr
  83             .as_ref()
  84             .expect("callback ctx should never be null")
  85             .lock()
  86             .unwrap();
  87         let Ok(new_list) = crate::list::list_interfaces() else {
  88             return;
  89         };
  90         handle_notif(state_guard, new_list);
  91     }
  92 }
  93
  94 fn handle_notif(state: &mut WatchState, new_list: List) {
  95     if new_list == state.prev_list {
  96         return;
  97     }
  98     let update = Update {
  99         interfaces: new_list.0.clone(),
 100         diff: new_list.diff_from(&state.prev_list),
 101     };
 102     (state.cb)(update);
 103     state.prev_list = new_list;
 104 }