Migrate PacketBuffer to use pkg/buffer

Benchmark iperf3:
                    Before      After
native->runsc       5.14        5.01    (Gbps)
runsc->native       4.15        4.07    (Gbps)

It did introduce overhead, mainly at the bridge between pkg/buffer and
VectorisedView, the ExtractVV method. Once endpoints start migrating away from
VV, this overhead will be gone.

Updates #2404

PiperOrigin-RevId: 373651666

1 files changed, 111 insertions, 0 deletions

diff --git a/pkg/buffer/buffer_test.go b/pkg/buffer/buffer_test.go
new file mode 100644
index 000000000..32db841e4
--- /dev/null
+++ b/pkg/buffer/buffer_test.go
@@ -0,0 +1,111 @@
+// 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 buffer
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestBufferRemove(t *testing.T) {
+	sample := []byte("01234567")
+
+	// Success cases
+	for _, tc := range []struct {
+		desc string
+		data []byte
+		rng  Range
+		want []byte
+	}{
+		{
+			desc: "empty slice",
+		},
+		{
+			desc: "empty range",
+			data: sample,
+			want: sample,
+		},
+		{
+			desc: "empty range with positive begin",
+			data: sample,
+			rng:  Range{begin: 1, end: 1},
+			want: sample,
+		},
+		{
+			desc: "range at beginning",
+			data: sample,
+			rng:  Range{begin: 0, end: 1},
+			want: sample[1:],
+		},
+		{
+			desc: "range in middle",
+			data: sample,
+			rng:  Range{begin: 2, end: 4},
+			want: []byte("014567"),
+		},
+		{
+			desc: "range at end",
+			data: sample,
+			rng:  Range{begin: 7, end: 8},
+			want: sample[:7],
+		},
+		{
+			desc: "range all",
+			data: sample,
+			rng:  Range{begin: 0, end: 8},
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			var buf buffer
+			buf.initWithData(tc.data)
+			if ok := buf.Remove(tc.rng); !ok {
+				t.Errorf("buf.Remove(%#v) = false, want true", tc.rng)
+			} else if got := buf.ReadSlice(); !bytes.Equal(got, tc.want) {
+				t.Errorf("buf.ReadSlice() = %q, want %q", got, tc.want)
+			}
+		})
+	}
+
+	// Failure cases
+	for _, tc := range []struct {
+		desc string
+		data []byte
+		rng  Range
+	}{
+		{
+			desc: "begin out-of-range",
+			data: sample,
+			rng:  Range{begin: -1, end: 4},
+		},
+		{
+			desc: "end out-of-range",
+			data: sample,
+			rng:  Range{begin: 4, end: 9},
+		},
+		{
+			desc: "both out-of-range",
+			data: sample,
+			rng:  Range{begin: -100, end: 100},
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			var buf buffer
+			buf.initWithData(tc.data)
+			if ok := buf.Remove(tc.rng); ok {
+				t.Errorf("buf.Remove(%#v) = true, want false", tc.rng)
+			}
+		})
+	}
+}