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-rw-r--r--pkg/iovec/BUILD18
-rw-r--r--pkg/iovec/iovec.go75
-rw-r--r--pkg/iovec/iovec_test.go121
-rw-r--r--pkg/sentry/fs/host/BUILD1
-rw-r--r--pkg/sentry/fs/host/socket_iovec.go7
-rw-r--r--pkg/sentry/fsimpl/host/BUILD1
-rw-r--r--pkg/sentry/fsimpl/host/socket_iovec.go7
-rw-r--r--pkg/tcpip/link/fdbased/BUILD1
-rw-r--r--pkg/tcpip/link/fdbased/endpoint.go69
-rw-r--r--pkg/tcpip/link/rawfile/rawfile_unsafe.go32
10 files changed, 246 insertions, 86 deletions
diff --git a/pkg/iovec/BUILD b/pkg/iovec/BUILD
new file mode 100644
index 000000000..eda82cfc1
--- /dev/null
+++ b/pkg/iovec/BUILD
@@ -0,0 +1,18 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+ name = "iovec",
+ srcs = ["iovec.go"],
+ visibility = ["//:sandbox"],
+ deps = ["//pkg/abi/linux"],
+)
+
+go_test(
+ name = "iovec_test",
+ size = "small",
+ srcs = ["iovec_test.go"],
+ library = ":iovec",
+ deps = ["@org_golang_x_sys//unix:go_default_library"],
+)
diff --git a/pkg/iovec/iovec.go b/pkg/iovec/iovec.go
new file mode 100644
index 000000000..dd70fe80f
--- /dev/null
+++ b/pkg/iovec/iovec.go
@@ -0,0 +1,75 @@
+// Copyright 2020 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
+
+// Package iovec provides helpers to interact with vectorized I/O on host
+// system.
+package iovec
+
+import (
+ "syscall"
+
+ "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 syscall.Iovec.
+type Builder struct {
+ iovec []syscall.Iovec
+ storage [8]syscall.Iovec
+
+ // overflow tracks the last buffer when iovec length is at MaxIovs.
+ overflow []byte
+}
+
+// Add adds buf to b preparing to be written. Zero-length buf won't be added.
+func (b *Builder) Add(buf []byte) {
+ if len(buf) == 0 {
+ return
+ }
+ if b.iovec == nil {
+ b.iovec = b.storage[:0]
+ }
+ if len(b.iovec) >= MaxIovs {
+ b.addByAppend(buf)
+ return
+ }
+ b.iovec = append(b.iovec, syscall.Iovec{
+ Base: &buf[0],
+ Len: uint64(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 {
+ n := len(buf)
+ b.overflow = buf[:n:n]
+ }
+}
+
+func (b *Builder) addByAppend(buf []byte) {
+ b.overflow = append(b.overflow, buf...)
+ b.iovec[len(b.iovec)-1] = syscall.Iovec{
+ Base: &b.overflow[0],
+ Len: uint64(len(b.overflow)),
+ }
+}
+
+// Build returns the final Iovec slice. The length of returned iovec will not
+// excceed MaxIovs.
+func (b *Builder) Build() []syscall.Iovec {
+ return b.iovec
+}
diff --git a/pkg/iovec/iovec_test.go b/pkg/iovec/iovec_test.go
new file mode 100644
index 000000000..a3900c299
--- /dev/null
+++ b/pkg/iovec/iovec_test.go
@@ -0,0 +1,121 @@
+// Copyright 2020 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
+
+package iovec
+
+import (
+ "bytes"
+ "fmt"
+ "syscall"
+ "testing"
+ "unsafe"
+
+ "golang.org/x/sys/unix"
+)
+
+func TestBuilderEmpty(t *testing.T) {
+ var builder Builder
+ iovecs := builder.Build()
+ if got, want := len(iovecs), 0; got != want {
+ t.Errorf("len(iovecs) = %d, want %d", got, want)
+ }
+}
+
+func TestBuilderBuild(t *testing.T) {
+ a := []byte{1, 2}
+ b := []byte{3, 4, 5}
+
+ var builder Builder
+ builder.Add(a)
+ builder.Add(b)
+ builder.Add(nil) // Nil slice won't be added.
+ builder.Add([]byte{}) // Empty slice won't be added.
+ iovecs := builder.Build()
+
+ if got, want := len(iovecs), 2; got != want {
+ t.Fatalf("len(iovecs) = %d, want %d", got, want)
+ }
+ for i, data := range [][]byte{a, b} {
+ if got, want := *iovecs[i].Base, data[0]; got != want {
+ t.Fatalf("*iovecs[%d].Base = %d, want %d", i, got, want)
+ }
+ if got, want := iovecs[i].Len, uint64(len(data)); got != want {
+ t.Fatalf("iovecs[%d].Len = %d, want %d", i, got, want)
+ }
+ }
+}
+
+func TestBuilderBuildMaxIov(t *testing.T) {
+ for _, test := range []struct {
+ numIov int
+ }{
+ {
+ numIov: MaxIovs - 1,
+ },
+ {
+ numIov: MaxIovs,
+ },
+ {
+ numIov: MaxIovs + 1,
+ },
+ {
+ numIov: MaxIovs + 10,
+ },
+ } {
+ name := fmt.Sprintf("numIov=%v", test.numIov)
+ t.Run(name, func(t *testing.T) {
+ var data []byte
+ var builder Builder
+ for i := 0; i < test.numIov; i++ {
+ buf := []byte{byte(i)}
+ builder.Add(buf)
+ data = append(data, buf...)
+ }
+ iovec := builder.Build()
+
+ // Check the expected length of iovec.
+ wantNum := test.numIov
+ if wantNum > MaxIovs {
+ wantNum = MaxIovs
+ }
+ if got, want := len(iovec), wantNum; got != want {
+ t.Errorf("len(iovec) = %d, want %d", got, want)
+ }
+
+ // Test a real read-write.
+ var fds [2]int
+ if err := unix.Pipe(fds[:]); err != nil {
+ t.Fatalf("Pipe: %v", err)
+ }
+ defer syscall.Close(fds[0])
+ defer syscall.Close(fds[1])
+
+ wrote, _, e := syscall.RawSyscall(syscall.SYS_WRITEV, uintptr(fds[1]), uintptr(unsafe.Pointer(&iovec[0])), uintptr(len(iovec)))
+ if int(wrote) != len(data) || e != 0 {
+ t.Fatalf("writev: %v, %v; want %v, 0", wrote, e, len(data))
+ }
+
+ got := make([]byte, len(data))
+ if n, err := syscall.Read(fds[0], got); n != len(got) || err != nil {
+ t.Fatalf("read: %v, %v; want %v, nil", n, err, len(got))
+ }
+
+ if !bytes.Equal(got, data) {
+ t.Errorf("read: got data %v, want %v", got, data)
+ }
+ })
+ }
+}
diff --git a/pkg/sentry/fs/host/BUILD b/pkg/sentry/fs/host/BUILD
index aabce6cc9..d41d23a43 100644
--- a/pkg/sentry/fs/host/BUILD
+++ b/pkg/sentry/fs/host/BUILD
@@ -30,6 +30,7 @@ go_library(
"//pkg/context",
"//pkg/fd",
"//pkg/fdnotifier",
+ "//pkg/iovec",
"//pkg/log",
"//pkg/refs",
"//pkg/safemem",
diff --git a/pkg/sentry/fs/host/socket_iovec.go b/pkg/sentry/fs/host/socket_iovec.go
index 5c18dbd5e..905afb50d 100644
--- a/pkg/sentry/fs/host/socket_iovec.go
+++ b/pkg/sentry/fs/host/socket_iovec.go
@@ -17,15 +17,12 @@ package host
import (
"syscall"
- "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/iovec"
"gvisor.dev/gvisor/pkg/syserror"
)
// LINT.IfChange
-// maxIovs is the maximum number of iovecs to pass to the host.
-var maxIovs = linux.UIO_MAXIOV
-
// copyToMulti copies as many bytes from src to dst as possible.
func copyToMulti(dst [][]byte, src []byte) {
for _, d := range dst {
@@ -76,7 +73,7 @@ func buildIovec(bufs [][]byte, maxlen int64, truncate bool) (length int64, iovec
}
}
- if iovsRequired > maxIovs {
+ if iovsRequired > iovec.MaxIovs {
// The kernel will reject our call if we pass this many iovs.
// Use a single intermediate buffer instead.
b := make([]byte, stopLen)
diff --git a/pkg/sentry/fsimpl/host/BUILD b/pkg/sentry/fsimpl/host/BUILD
index 44a09d87a..e86fbe2d5 100644
--- a/pkg/sentry/fsimpl/host/BUILD
+++ b/pkg/sentry/fsimpl/host/BUILD
@@ -22,6 +22,7 @@ go_library(
"//pkg/context",
"//pkg/fdnotifier",
"//pkg/fspath",
+ "//pkg/iovec",
"//pkg/log",
"//pkg/refs",
"//pkg/safemem",
diff --git a/pkg/sentry/fsimpl/host/socket_iovec.go b/pkg/sentry/fsimpl/host/socket_iovec.go
index 584c247d2..fc0d5fd38 100644
--- a/pkg/sentry/fsimpl/host/socket_iovec.go
+++ b/pkg/sentry/fsimpl/host/socket_iovec.go
@@ -17,13 +17,10 @@ package host
import (
"syscall"
- "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/iovec"
"gvisor.dev/gvisor/pkg/syserror"
)
-// maxIovs is the maximum number of iovecs to pass to the host.
-var maxIovs = linux.UIO_MAXIOV
-
// copyToMulti copies as many bytes from src to dst as possible.
func copyToMulti(dst [][]byte, src []byte) {
for _, d := range dst {
@@ -74,7 +71,7 @@ func buildIovec(bufs [][]byte, maxlen int64, truncate bool) (length int64, iovec
}
}
- if iovsRequired > maxIovs {
+ if iovsRequired > iovec.MaxIovs {
// The kernel will reject our call if we pass this many iovs.
// Use a single intermediate buffer instead.
b := make([]byte, stopLen)
diff --git a/pkg/tcpip/link/fdbased/BUILD b/pkg/tcpip/link/fdbased/BUILD
index aa6db9aea..507b44abc 100644
--- a/pkg/tcpip/link/fdbased/BUILD
+++ b/pkg/tcpip/link/fdbased/BUILD
@@ -15,6 +15,7 @@ go_library(
visibility = ["//visibility:public"],
deps = [
"//pkg/binary",
+ "//pkg/iovec",
"//pkg/sync",
"//pkg/tcpip",
"//pkg/tcpip/buffer",
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index 32abe2a13..6aa1badc7 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -45,6 +45,7 @@ import (
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/iovec"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -406,6 +407,8 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
eth.Encode(ethHdr)
}
+ var builder iovec.Builder
+
fd := e.fds[pkt.Hash%uint32(len(e.fds))]
if e.Capabilities()&stack.CapabilityHardwareGSO != 0 {
vnetHdr := virtioNetHdr{}
@@ -430,29 +433,25 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
}
vnetHdrBuf := binary.Marshal(make([]byte, 0, virtioNetHdrSize), binary.LittleEndian, vnetHdr)
- return rawfile.NonBlockingWrite3(fd, vnetHdrBuf, pkt.Header.View(), pkt.Data.ToView())
+ builder.Add(vnetHdrBuf)
}
- if pkt.Data.Size() == 0 {
- return rawfile.NonBlockingWrite(fd, pkt.Header.View())
- }
- if pkt.Header.UsedLength() == 0 {
- return rawfile.NonBlockingWrite(fd, pkt.Data.ToView())
+ builder.Add(pkt.Header.View())
+ for _, v := range pkt.Data.Views() {
+ builder.Add(v)
}
- return rawfile.NonBlockingWrite3(fd, pkt.Header.View(), pkt.Data.ToView(), nil)
+ return rawfile.NonBlockingWriteIovec(fd, builder.Build())
}
func (e *endpoint) sendBatch(batchFD int, batch []*stack.PacketBuffer) (int, *tcpip.Error) {
// Send a batch of packets through batchFD.
mmsgHdrs := make([]rawfile.MMsgHdr, 0, len(batch))
for _, pkt := range batch {
- var ethHdrBuf []byte
- iovLen := 0
+ var eth header.Ethernet
if e.hdrSize > 0 {
// Add ethernet header if needed.
- ethHdrBuf = make([]byte, header.EthernetMinimumSize)
- eth := header.Ethernet(ethHdrBuf)
+ eth = make(header.Ethernet, header.EthernetMinimumSize)
ethHdr := &header.EthernetFields{
DstAddr: pkt.EgressRoute.RemoteLinkAddress,
Type: pkt.NetworkProtocolNumber,
@@ -465,12 +464,11 @@ func (e *endpoint) sendBatch(batchFD int, batch []*stack.PacketBuffer) (int, *tc
ethHdr.SrcAddr = e.addr
}
eth.Encode(ethHdr)
- iovLen++
}
- vnetHdr := virtioNetHdr{}
var vnetHdrBuf []byte
if e.Capabilities()&stack.CapabilityHardwareGSO != 0 {
+ vnetHdr := virtioNetHdr{}
if pkt.GSOOptions != nil {
vnetHdr.hdrLen = uint16(pkt.Header.UsedLength())
if pkt.GSOOptions.NeedsCsum {
@@ -491,45 +489,20 @@ func (e *endpoint) sendBatch(batchFD int, batch []*stack.PacketBuffer) (int, *tc
}
}
vnetHdrBuf = binary.Marshal(make([]byte, 0, virtioNetHdrSize), binary.LittleEndian, vnetHdr)
- iovLen++
}
- iovecs := make([]syscall.Iovec, iovLen+1+len(pkt.Data.Views()))
+ var builder iovec.Builder
+ builder.Add(vnetHdrBuf)
+ builder.Add(eth)
+ builder.Add(pkt.Header.View())
+ for _, v := range pkt.Data.Views() {
+ builder.Add(v)
+ }
+ iovecs := builder.Build()
+
var mmsgHdr rawfile.MMsgHdr
mmsgHdr.Msg.Iov = &iovecs[0]
- iovecIdx := 0
- if vnetHdrBuf != nil {
- v := &iovecs[iovecIdx]
- v.Base = &vnetHdrBuf[0]
- v.Len = uint64(len(vnetHdrBuf))
- iovecIdx++
- }
- if ethHdrBuf != nil {
- v := &iovecs[iovecIdx]
- v.Base = &ethHdrBuf[0]
- v.Len = uint64(len(ethHdrBuf))
- iovecIdx++
- }
- pktSize := uint64(0)
- // Encode L3 Header
- v := &iovecs[iovecIdx]
- hdr := &pkt.Header
- hdrView := hdr.View()
- v.Base = &hdrView[0]
- v.Len = uint64(len(hdrView))
- pktSize += v.Len
- iovecIdx++
-
- // Now encode the Transport Payload.
- pktViews := pkt.Data.Views()
- for i := range pktViews {
- vec := &iovecs[iovecIdx]
- iovecIdx++
- vec.Base = &pktViews[i][0]
- vec.Len = uint64(len(pktViews[i]))
- pktSize += vec.Len
- }
- mmsgHdr.Msg.Iovlen = uint64(iovecIdx)
+ mmsgHdr.Msg.Iovlen = uint64(len(iovecs))
mmsgHdrs = append(mmsgHdrs, mmsgHdr)
}
diff --git a/pkg/tcpip/link/rawfile/rawfile_unsafe.go b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
index 69de6eb3e..f4c32c2da 100644
--- a/pkg/tcpip/link/rawfile/rawfile_unsafe.go
+++ b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
@@ -66,38 +66,14 @@ func NonBlockingWrite(fd int, buf []byte) *tcpip.Error {
return nil
}
-// NonBlockingWrite3 writes up to three byte slices to a file descriptor in a
-// single syscall. It fails if partial data is written.
-func NonBlockingWrite3(fd int, b1, b2, b3 []byte) *tcpip.Error {
- // If there is no second and third buffer, issue a regular write.
- if len(b2) == 0 && len(b3) == 0 {
- return NonBlockingWrite(fd, b1)
- }
-
- // Build the iovec that represents them and issue a writev syscall.
- iovec := [3]syscall.Iovec{
- {
- Base: &b1[0],
- Len: uint64(len(b1)),
- },
- {
- Base: &b2[0],
- Len: uint64(len(b2)),
- },
- }
- iovecLen := uintptr(2)
-
- if len(b3) > 0 {
- iovecLen++
- iovec[2].Base = &b3[0]
- iovec[2].Len = uint64(len(b3))
- }
-
+// NonBlockingWriteIovec writes iovec to a file descriptor in a single syscall.
+// It fails if partial data is written.
+func NonBlockingWriteIovec(fd int, iovec []syscall.Iovec) *tcpip.Error {
+ iovecLen := uintptr(len(iovec))
_, _, e := syscall.RawSyscall(syscall.SYS_WRITEV, uintptr(fd), uintptr(unsafe.Pointer(&iovec[0])), iovecLen)
if e != 0 {
return TranslateErrno(e)
}
-
return nil
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 21:52:14 +0000