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Make netstack (//pkg/tcpip) buildable for 32 bit

Browse Source 
Doing so involved breaking dependencies between //pkg/tcpip and the rest
of gVisor, which are discouraged anyways.

Tested on the Go branch via:
  gvisor.dev/gvisor/pkg/tcpip/...

Addresses #1446.

PiperOrigin-RevId: 363081778
This commit is contained in:
Kevin Krakauer
2021-03-15 18:49:59 -07:00
committed by gVisor bot
parent ec45d96923
commit b1d5787726
11 changed files with 124 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/iovec/BUILD
+5 -5
View File
@@ -4,12 +4,12 @@ package(licenses = ["notice"])
go_library(
name = "iovec",
srcs = ["iovec.go"],
visibility = ["//:sandbox"],
deps = [
"//pkg/abi/linux",
"@org_golang_x_sys//unix:go_default_library",
srcs = [
"iovec.go",
"iovec_max.go",
],
visibility = ["//:sandbox"],
deps = ["@org_golang_x_sys//unix:go_default_library"],
)
go_test(
pkg/iovec/iovec.go
+6 -12
View File
@@ -20,12 +20,8 @@ package iovec
import (
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/abi/linux"
)
// MaxIovs is the maximum number of iovecs host platform can accept.
var MaxIovs = linux.UIO_MAXIOV
// Builder is a builder for slice of unix.Iovec.
type Builder struct {
iovec []unix.Iovec
@@ -47,10 +43,10 @@ func (b *Builder) Add(buf []byte) {
b.addByAppend(buf)
return
}
b.iovec = append(b.iovec, unix.Iovec{
Base: &buf[0],
Len: uint64(len(buf)),
})
b.iovec = append(b.iovec, unix.Iovec{Base: &buf[0]})
b.iovec[len(b.iovec)-1].SetLen(len(buf))
// Keep the last buf if iovec is at max capacity. We will need to append to it
// for later bufs.
if len(b.iovec) == MaxIovs {
@@ -61,10 +57,8 @@ func (b *Builder) Add(buf []byte) {
func (b *Builder) addByAppend(buf []byte) {
b.overflow = append(b.overflow, buf...)
b.iovec[len(b.iovec)-1] = unix.Iovec{
Base: &b.overflow[0],
Len: uint64(len(b.overflow)),
}
b.iovec[len(b.iovec)-1] = unix.Iovec{Base: &b.overflow[0]}
b.iovec[len(b.iovec)-1].SetLen(len(b.overflow))
}
// Build returns the final Iovec slice. The length of returned iovec will not
pkg/iovec/iovec_max.go
+19
View File
@@ -0,0 +1,19 @@
// Copyright 2021 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.
package iovec
// MaxIovs is the maximum number of iovecs host platform can accept. It
// corresponds to Linux's UIO_MAXIOV, which is not in the unix package.
const MaxIovs = 1024
pkg/sentry/devices/tundev/tundev.go
+7 -8
View File
@@ -87,19 +87,18 @@ func (fd *tunFD) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArg
if _, err := req.CopyIn(t, data); err != nil {
return 0, err
}
flags := usermem.ByteOrder.Uint16(req.Data[:])
// Validate flags.
flags, err := netstack.LinuxToTUNFlags(usermem.ByteOrder.Uint16(req.Data[:]))
if err != nil {
return 0, err
}
return 0, fd.device.SetIff(stack.Stack, req.Name(), flags)
case linux.TUNGETIFF:
var req linux.IFReq
copy(req.IFName[:], fd.device.Name())
// Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately) when
// there is no sk_filter. See __tun_chr_ioctl() in net/drivers/tun.c.
flags := fd.device.Flags() | linux.IFF_NOFILTER
usermem.ByteOrder.PutUint16(req.Data[:], flags)
usermem.ByteOrder.PutUint16(req.Data[:], netstack.TUNFlagsToLinux(fd.device.Flags()))
_, err := req.CopyOut(t, data)
return 0, err
pkg/sentry/fs/dev/net_tun.go
+7 -8
View File
@@ -108,19 +108,18 @@ func (n *netTunFileOperations) Ioctl(ctx context.Context, file *fs.File, io user
if _, err := req.CopyIn(t, data); err != nil {
return 0, err
}
flags := usermem.ByteOrder.Uint16(req.Data[:])
// Validate flags.
flags, err := netstack.LinuxToTUNFlags(usermem.ByteOrder.Uint16(req.Data[:]))
if err != nil {
return 0, err
}
return 0, n.device.SetIff(stack.Stack, req.Name(), flags)
case linux.TUNGETIFF:
var req linux.IFReq
copy(req.IFName[:], n.device.Name())
// Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately) when
// there is no sk_filter. See __tun_chr_ioctl() in net/drivers/tun.c.
flags := n.device.Flags() | linux.IFF_NOFILTER
usermem.ByteOrder.PutUint16(req.Data[:], flags)
usermem.ByteOrder.PutUint16(req.Data[:], netstack.TUNFlagsToLinux(n.device.Flags()))
_, err := req.CopyOut(t, data)
return 0, err
pkg/sentry/socket/netstack/BUILD
+2
View File
@@ -12,6 +12,7 @@ go_library(
"provider_vfs2.go",
"save_restore.go",
"stack.go",
"tun.go",
],
visibility = [
"//pkg/sentry:internal",
@@ -42,6 +43,7 @@ go_library(
"//pkg/syserror",
"//pkg/tcpip",
"//pkg/tcpip/header",
"//pkg/tcpip/link/tun",
"//pkg/tcpip/network/ipv4",
"//pkg/tcpip/network/ipv6",
"//pkg/tcpip/stack",
pkg/sentry/socket/netstack/tun.go
+51
View File
@@ -0,0 +1,51 @@
// Copyright 2021 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.
package netstack
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/tcpip/link/tun"
)
// TUNFlagsToLinux converts a tun.Flags to Linux TUN flags.
func TUNFlagsToLinux(flags tun.Flags) uint16 {
ret := uint16(linux.IFF_NOFILTER)
if flags.TAP {
ret |= linux.IFF_TAP
}
if flags.TUN {
ret |= linux.IFF_TUN
}
if flags.NoPacketInfo {
ret |= linux.IFF_NO_PI
}
return ret
}
// LinuxToTUNFlags converts Linux TUN flags to a tun.Flags.
func LinuxToTUNFlags(flags uint16) (tun.Flags, error) {
// Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately)
// when there is no sk_filter. See __tun_chr_ioctl() in
// net/drivers/tun.c.
if flags&^uint16(linux.IFF_TUN|linux.IFF_TAP|linux.IFF_NO_PI) != 0 {
return tun.Flags{}, syserror.EINVAL
}
return tun.Flags{
TUN: flags&linux.IFF_TUN != 0,
TAP: flags&linux.IFF_TAP != 0,
NoPacketInfo: flags&linux.IFF_NO_PI != 0,
}, nil
}
pkg/tcpip/link/fdbased/endpoint.go
+1 -1
View File
@@ -492,7 +492,7 @@ func (e *endpoint) sendBatch(batchFD int, batch []*stack.PacketBuffer) (int, tcp
var mmsgHdr rawfile.MMsgHdr
mmsgHdr.Msg.Iov = &iovecs[0]
mmsgHdr.Msg.Iovlen = uint64(len(iovecs))
mmsgHdr.Msg.SetIovlen((len(iovecs)))
mmsgHdrs = append(mmsgHdrs, mmsgHdr)
}
pkg/tcpip/link/fdbased/packet_dispatchers.go
+5 -9
View File
@@ -68,10 +68,8 @@ func (b *iovecBuffer) nextIovecs() []unix.Iovec {
// The kernel adds virtioNetHdr before each packet, but
// we don't use it, so so we allocate a buffer for it,
// add it in iovecs but don't add it in a view.
b.iovecs[0] = unix.Iovec{
Base: &vnetHdr[0],
Len: uint64(virtioNetHdrSize),
}
b.iovecs[0] = unix.Iovec{Base: &vnetHdr[0]}
b.iovecs[0].SetLen(virtioNetHdrSize)
vnetHdrOff++
}
for i := range b.views {
@@ -80,10 +78,8 @@ func (b *iovecBuffer) nextIovecs() []unix.Iovec {
}
v := buffer.NewView(b.sizes[i])
b.views[i] = v
b.iovecs[i+vnetHdrOff] = unix.Iovec{
Base: &v[0],
Len: uint64(len(v)),
}
b.iovecs[i+vnetHdrOff] = unix.Iovec{Base: &v[0]}
b.iovecs[i+vnetHdrOff].SetLen(len(v))
}
return b.iovecs
}
@@ -235,7 +231,7 @@ func (d *recvMMsgDispatcher) dispatch() (bool, tcpip.Error) {
iovLen := len(iovecs)
d.msgHdrs[k].Len = 0
d.msgHdrs[k].Msg.Iov = &iovecs[0]
d.msgHdrs[k].Msg.Iovlen = uint64(iovLen)
d.msgHdrs[k].Msg.SetIovlen(iovLen)
}
nMsgs, err := rawfile.BlockingRecvMMsg(d.fd, d.msgHdrs)
pkg/tcpip/link/tun/device.go
+18 -19
View File
@@ -17,7 +17,6 @@ package tun
import (
"fmt"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
@@ -49,7 +48,14 @@ type Device struct {
mu sync.RWMutex `state:"nosave"`
endpoint *tunEndpoint
notifyHandle *channel.NotificationHandle
flags uint16
flags Flags
}
// Flags set properties of a Device
type Flags struct {
TUN bool
TAP bool
NoPacketInfo bool
}
// beforeSave is invoked by stateify.
@@ -77,7 +83,7 @@ func (d *Device) Release(ctx context.Context) {
}
// SetIff services TUNSETIFF ioctl(2) request.
func (d *Device) SetIff(s *stack.Stack, name string, flags uint16) error {
func (d *Device) SetIff(s *stack.Stack, name string, flags Flags) error {
d.mu.Lock()
defer d.mu.Unlock()
@@ -85,21 +91,18 @@ func (d *Device) SetIff(s *stack.Stack, name string, flags uint16) error {
return syserror.EINVAL
}
// Input validations.
isTun := flags&linux.IFF_TUN != 0
isTap := flags&linux.IFF_TAP != 0
supportedFlags := uint16(linux.IFF_TUN | linux.IFF_TAP | linux.IFF_NO_PI)
if isTap && isTun || !isTap && !isTun || flags&^supportedFlags != 0 {
// Input validation.
if flags.TAP && flags.TUN || !flags.TAP && !flags.TUN {
return syserror.EINVAL
}
prefix := "tun"
if isTap {
if flags.TAP {
prefix = "tap"
}
linkCaps := stack.CapabilityNone
if isTap {
if flags.TAP {
linkCaps |= stack.CapabilityResolutionRequired
}
@@ -177,7 +180,7 @@ func (d *Device) Write(data []byte) (int64, error) {
// Packet information.
var pktInfoHdr PacketInfoHeader
if !d.hasFlags(linux.IFF_NO_PI) {
if !d.flags.NoPacketInfo {
if len(data) < PacketInfoHeaderSize {
// Ignore bad packet.
return dataLen, nil
@@ -188,7 +191,7 @@ func (d *Device) Write(data []byte) (int64, error) {
// Ethernet header (TAP only).
var ethHdr header.Ethernet
if d.hasFlags(linux.IFF_TAP) {
if d.flags.TAP {
if len(data) < header.EthernetMinimumSize {
// Ignore bad packet.
return dataLen, nil
@@ -253,7 +256,7 @@ func (d *Device) encodePkt(info *channel.PacketInfo) (buffer.View, bool) {
var vv buffer.VectorisedView
// Packet information.
if !d.hasFlags(linux.IFF_NO_PI) {
if !d.flags.NoPacketInfo {
hdr := make(PacketInfoHeader, PacketInfoHeaderSize)
hdr.Encode(&PacketInfoFields{
Protocol: info.Proto,
@@ -269,7 +272,7 @@ func (d *Device) encodePkt(info *channel.PacketInfo) (buffer.View, bool) {
}
// Ethernet header (TAP only).
if d.hasFlags(linux.IFF_TAP) {
if d.flags.TAP {
// Add ethernet header if not provided.
if info.Pkt.LinkHeader().View().IsEmpty() {
d.endpoint.AddHeader(info.Route.LocalLinkAddress, info.Route.RemoteLinkAddress, info.Proto, info.Pkt)
@@ -298,16 +301,12 @@ func (d *Device) Name() string {
}
// Flags returns the flags set for d. Zero value if unset.
func (d *Device) Flags() uint16 {
func (d *Device) Flags() Flags {
d.mu.RLock()
defer d.mu.RUnlock()
return d.flags
}
func (d *Device) hasFlags(flags uint16) bool {
return d.flags&flags == flags
}
// Readiness implements watier.Waitable.Readiness.
func (d *Device) Readiness(mask waiter.EventMask) waiter.EventMask {
if mask&waiter.EventIn != 0 {
pkg/tcpip/transport/tcp/snd.go
+3 -1
View File
@@ -323,7 +323,9 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
// their initial values.
func (s *sender) initCongestionControl(congestionControlName tcpip.CongestionControlOption) congestionControl {
s.sndCwnd = InitialCwnd
s.sndSsthresh = math.MaxInt64
// Set sndSsthresh to the maximum int value, which depends on the
// platform.
s.sndSsthresh = int(^uint(0) >> 1)
switch congestionControlName {
case ccCubic: