tun: windows: silently drop packet when ring is full

diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 21bc38288e41904bb974111b4dc5697dd8fc5570..86995a77cc9546b3d22fcfe53aaf52d54a6b5e58 100644 (file)
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -22,7 +22,7 @@ import (
 const (
        packetAlignment    uint32 = 4        // Number of bytes packets are aligned to in rings
        packetSizeMax      uint32 = 0xffff   // Maximum packet size
-       packetCapacity     uint32 = 0x100000 // Ring capacity (defaults to 1MiB, must be a power of 2)
+       packetCapacity     uint32 = 0x800000 // Ring capacity, 8MiB
        packetTrailingSize uint32 = uint32(unsafe.Sizeof(packetHeader{})) + ((packetSizeMax + (packetAlignment - 1)) &^ (packetAlignment - 1)) - packetAlignment
 
        ioctlRegisterRings uint32 = (0x22 /*FILE_DEVICE_UNKNOWN*/ << 16) | (0x800 << 2) | 0 /*METHOD_BUFFERED*/ | (0x3 /*FILE_READ_DATA | FILE_WRITE_DATA*/ << 14)
@@ -381,7 +381,7 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 
                buffSpace := tun.rings.receive.ring.wrap(buffHead - buffTail - packetAlignment)
                if alignedPacketSize > buffSpace {
-                       return 0, errors.New("receive ring full")
+                       return 0, nil // Dropping when ring is full.
                }
 
                packet := (*packet)(unsafe.Pointer(&tun.rings.receive.ring.data[buffTail]))