From 8091c6474a545fec806fd1a3611d7cb50a099746 Mon Sep 17 00:00:00 2001 From: Simon Rozman Date: Wed, 20 Feb 2019 19:56:10 +0100 Subject: [PATCH] wintun: Adopt new packet data alignment Signed-off-by: Simon Rozman --- tun/tun_windows.go | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/tun/tun_windows.go b/tun/tun_windows.go index 5f9c0f4..838fdd1 100644 --- a/tun/tun_windows.go +++ b/tun/tun_windows.go @@ -16,11 +16,11 @@ import ( ) const ( - packetSizeMax uint32 = 0xeffc // Maximum packet size: 4 + packetSizeMax == 0xf000 - packetExchangeMax uint32 = 256 // Number of packets that may be written at a time - packetExchangeAlignment uint32 = 16 // Number of bytes packets are aligned to in exchange buffers - packetExchangeSizeRead uint32 = 0x100000 // Read exchange buffer size (defaults to 1MiB) - packetExchangeSizeWrite uint32 = 0x10000 // Write exchange buffer size (defaults to 64kiB) + packetExchangeMax uint32 = 256 // Number of packets that may be written at a time + packetExchangeAlignment uint32 = 16 // Number of bytes packets are aligned to in exchange buffers + packetSizeMax uint32 = 0xf000 - packetExchangeAlignment // Maximum packet size + packetExchangeSizeRead uint32 = 0x100000 // Read exchange buffer size (defaults to 1MiB) + packetExchangeSizeWrite uint32 = 0x10000 // Write exchange buffer size (defaults to 64kiB) ) type exchgBufRead struct { @@ -228,10 +228,10 @@ func (tun *nativeTun) Read(buff []byte, offset int) (int, error) { } for { - if tun.rdBuff.offset+4 <= tun.rdBuff.avail { + if tun.rdBuff.offset+packetExchangeAlignment <= tun.rdBuff.avail { // Get packet from the exchange buffer. size := *(*uint32)(unsafe.Pointer(&tun.rdBuff.data[tun.rdBuff.offset])) - pSize := packetAlign(4 + size) + pSize := packetAlign(packetExchangeAlignment + size) if packetSizeMax < size || tun.rdBuff.avail < tun.rdBuff.offset+pSize { // Invalid packet size. tun.rdBuff.avail = 0 @@ -239,7 +239,7 @@ func (tun *nativeTun) Read(buff []byte, offset int) (int, error) { } // Copy data. - copy(buff[offset:], tun.rdBuff.data[tun.rdBuff.offset+4:][:size]) + copy(buff[offset:], tun.rdBuff.data[tun.rdBuff.offset+packetExchangeAlignment:][:size]) tun.rdBuff.offset += pSize return int(size), nil } @@ -319,7 +319,7 @@ func (tun *nativeTun) putTunPacket(buff []byte) error { if size > packetSizeMax { return errors.New("Packet too big") } - pSize := packetAlign(4 + size) + pSize := packetAlign(packetExchangeAlignment + size) if tun.wrBuff.packetNum >= packetExchangeMax || tun.wrBuff.offset+pSize >= packetExchangeSizeWrite { // Exchange buffer is full -> flush first. @@ -331,7 +331,7 @@ func (tun *nativeTun) putTunPacket(buff []byte) error { // Write packet to the exchange buffer. *(*uint32)(unsafe.Pointer(&tun.wrBuff.data[tun.wrBuff.offset])) = size - copy(tun.wrBuff.data[tun.wrBuff.offset+4:][:size], buff) + copy(tun.wrBuff.data[tun.wrBuff.offset+packetExchangeAlignment:][:size], buff) tun.wrBuff.packetNum++ tun.wrBuff.offset += pSize