diff options
Diffstat (limited to 'pkg/tcpip/link/fdbased/mmap_amd64.go')
| -rw-r--r-- | pkg/tcpip/link/fdbased/mmap_amd64.go | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/pkg/tcpip/link/fdbased/mmap_amd64.go b/pkg/tcpip/link/fdbased/mmap_amd64.go deleted file mode 100644 index 029f86a18..000000000 --- a/pkg/tcpip/link/fdbased/mmap_amd64.go +++ /dev/null @@ -1,194 +0,0 @@ -// Copyright 2019 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// +build linux,amd64 - -package fdbased - -import ( - "encoding/binary" - "syscall" - - "golang.org/x/sys/unix" - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/buffer" - "gvisor.dev/gvisor/pkg/tcpip/header" - "gvisor.dev/gvisor/pkg/tcpip/link/rawfile" -) - -const ( - tPacketAlignment = uintptr(16) - tpStatusKernel = 0 - tpStatusUser = 1 - tpStatusCopy = 2 - tpStatusLosing = 4 -) - -// We overallocate the frame size to accommodate space for the -// TPacketHdr+RawSockAddrLinkLayer+MAC header and any padding. -// -// Memory allocated for the ring buffer: tpBlockSize * tpBlockNR = 2 MiB -// -// NOTE: -// Frames need to be aligned at 16 byte boundaries. -// BlockSize needs to be page aligned. -// -// For details see PACKET_MMAP setting constraints in -// https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt -const ( - tpFrameSize = 65536 + 128 - tpBlockSize = tpFrameSize * 32 - tpBlockNR = 1 - tpFrameNR = (tpBlockSize * tpBlockNR) / tpFrameSize -) - -// tPacketAlign aligns the pointer v at a tPacketAlignment boundary. Direct -// translation of the TPACKET_ALIGN macro in <linux/if_packet.h>. -func tPacketAlign(v uintptr) uintptr { - return (v + tPacketAlignment - 1) & uintptr(^(tPacketAlignment - 1)) -} - -// tPacketReq is the tpacket_req structure as described in -// https://www.kernel.org/doc/Documentation/networking/packet_mmap.txt -type tPacketReq struct { - tpBlockSize uint32 - tpBlockNR uint32 - tpFrameSize uint32 - tpFrameNR uint32 -} - -// tPacketHdr is tpacket_hdr structure as described in <linux/if_packet.h> -type tPacketHdr []byte - -const ( - tpStatusOffset = 0 - tpLenOffset = 8 - tpSnapLenOffset = 12 - tpMacOffset = 16 - tpNetOffset = 18 - tpSecOffset = 20 - tpUSecOffset = 24 -) - -func (t tPacketHdr) tpLen() uint32 { - return binary.LittleEndian.Uint32(t[tpLenOffset:]) -} - -func (t tPacketHdr) tpSnapLen() uint32 { - return binary.LittleEndian.Uint32(t[tpSnapLenOffset:]) -} - -func (t tPacketHdr) tpMac() uint16 { - return binary.LittleEndian.Uint16(t[tpMacOffset:]) -} - -func (t tPacketHdr) tpNet() uint16 { - return binary.LittleEndian.Uint16(t[tpNetOffset:]) -} - -func (t tPacketHdr) tpSec() uint32 { - return binary.LittleEndian.Uint32(t[tpSecOffset:]) -} - -func (t tPacketHdr) tpUSec() uint32 { - return binary.LittleEndian.Uint32(t[tpUSecOffset:]) -} - -func (t tPacketHdr) Payload() []byte { - return t[uint32(t.tpMac()) : uint32(t.tpMac())+t.tpSnapLen()] -} - -// packetMMapDispatcher uses PACKET_RX_RING's to read/dispatch inbound packets. -// See: mmap_amd64_unsafe.go for implementation details. -type packetMMapDispatcher struct { - // fd is the file descriptor used to send and receive packets. - fd int - - // e is the endpoint this dispatcher is attached to. - e *endpoint - - // ringBuffer is only used when PacketMMap dispatcher is used and points - // to the start of the mmapped PACKET_RX_RING buffer. - ringBuffer []byte - - // ringOffset is the current offset into the ring buffer where the next - // inbound packet will be placed by the kernel. - ringOffset int -} - -func (d *packetMMapDispatcher) readMMappedPacket() ([]byte, *tcpip.Error) { - hdr := tPacketHdr(d.ringBuffer[d.ringOffset*tpFrameSize:]) - for hdr.tpStatus()&tpStatusUser == 0 { - event := rawfile.PollEvent{ - FD: int32(d.fd), - Events: unix.POLLIN | unix.POLLERR, - } - if _, errno := rawfile.BlockingPoll(&event, 1, nil); errno != 0 { - if errno == syscall.EINTR { - continue - } - return nil, rawfile.TranslateErrno(errno) - } - if hdr.tpStatus()&tpStatusCopy != 0 { - // This frame is truncated so skip it after flipping the - // buffer to the kernel. - hdr.setTPStatus(tpStatusKernel) - d.ringOffset = (d.ringOffset + 1) % tpFrameNR - hdr = (tPacketHdr)(d.ringBuffer[d.ringOffset*tpFrameSize:]) - continue - } - } - - // Copy out the packet from the mmapped frame to a locally owned buffer. - pkt := make([]byte, hdr.tpSnapLen()) - copy(pkt, hdr.Payload()) - // Release packet to kernel. - hdr.setTPStatus(tpStatusKernel) - d.ringOffset = (d.ringOffset + 1) % tpFrameNR - return pkt, nil -} - -// dispatch reads packets from an mmaped ring buffer and dispatches them to the -// network stack. -func (d *packetMMapDispatcher) dispatch() (bool, *tcpip.Error) { - pkt, err := d.readMMappedPacket() - if err != nil { - return false, err - } - var ( - p tcpip.NetworkProtocolNumber - remote, local tcpip.LinkAddress - ) - if d.e.hdrSize > 0 { - eth := header.Ethernet(pkt) - p = eth.Type() - remote = eth.SourceAddress() - local = eth.DestinationAddress() - } else { - // We don't get any indication of what the packet is, so try to guess - // if it's an IPv4 or IPv6 packet. - switch header.IPVersion(pkt) { - case header.IPv4Version: - p = header.IPv4ProtocolNumber - case header.IPv6Version: - p = header.IPv6ProtocolNumber - default: - return true, nil - } - } - - pkt = pkt[d.e.hdrSize:] - d.e.dispatcher.DeliverNetworkPacket(d.e, remote, local, p, buffer.NewVectorisedView(len(pkt), []buffer.View{buffer.View(pkt)})) - return true, nil -} |