Make dedicated methods for data operations in PacketBuffer

One of the preparation to decouple underlying buffer implementation.
There are still some methods that tie to VectorisedView, and they will be
changed gradually in later CLs.

This CL also introduce a new ICMPv6ChecksumParams to replace long list of
parameters when calling ICMPv6Checksum, aiming to be more descriptive.

PiperOrigin-RevId: 360778149

1 files changed, 53 insertions, 60 deletions

diff --git a/pkg/tcpip/header/checksum_test.go b/pkg/tcpip/header/checksum_test.go
index 5ab20ee86..d267dabd0 100644
--- a/pkg/tcpip/header/checksum_test.go
+++ b/pkg/tcpip/header/checksum_test.go
@@ -17,6 +17,7 @@
 package header_test
 
 import (
+	"bytes"
 	"fmt"
 	"math/rand"
 	"sync"
@@ -26,86 +27,72 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 )
 
-func TestChecksumVVWithOffset(t *testing.T) {
+func TestChecksumer(t *testing.T) {
 	testCases := []struct {
-		name      string
-		vv        buffer.VectorisedView
-		off, size int
-		initial   uint16
-		want      uint16
+		name string
+		data [][]byte
+		want uint16
 	}{
 		{
 			name: "empty",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{1, 9, 0, 5, 4}),
-			}),
-			off:  0,
-			size: 0,
 			want: 0,
 		},
 		{
-			name: "OneView",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{1, 9, 0, 5, 4}),
-			}),
-			off:  0,
-			size: 5,
+			name: "OneOddView",
+			data: [][]byte{
+				[]byte{1, 9, 0, 5, 4},
+			},
 			want: 1294,
 		},
 		{
-			name: "TwoViews",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{1, 9, 0, 5, 4}),
-				buffer.NewViewFromBytes([]byte{4, 3, 7, 1, 2, 123}),
-			}),
-			off:  0,
-			size: 11,
+			name: "TwoOddViews",
+			data: [][]byte{
+				[]byte{1, 9, 0, 5, 4},
+				[]byte{4, 3, 7, 1, 2, 123},
+			},
 			want: 33819,
 		},
 		{
-			name: "TwoViewsWithOffset",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{98, 1, 9, 0, 5, 4}),
-				buffer.NewViewFromBytes([]byte{4, 3, 7, 1, 2, 123}),
-			}),
-			off:  1,
-			size: 11,
-			want: 33819,
+			name: "OneEvenView",
+			data: [][]byte{
+				[]byte{1, 9, 0, 5},
+			},
+			want: 270,
 		},
 		{
-			name: "ThreeViewsWithOffset",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{98, 1, 9, 0, 5, 4}),
-				buffer.NewViewFromBytes([]byte{98, 1, 9, 0, 5, 4}),
-				buffer.NewViewFromBytes([]byte{4, 3, 7, 1, 2, 123}),
-			}),
-			off:  7,
-			size: 11,
-			want: 33819,
+			name: "TwoEvenViews",
+			data: [][]byte{
+				buffer.NewViewFromBytes([]byte{98, 1, 9, 0}),
+				buffer.NewViewFromBytes([]byte{9, 0, 5, 4}),
+			},
+			want: 30981,
 		},
 		{
-			name: "ThreeViewsWithInitial",
-			vv: buffer.NewVectorisedView(0, []buffer.View{
-				buffer.NewViewFromBytes([]byte{77, 11, 33, 0, 55, 44}),
-				buffer.NewViewFromBytes([]byte{98, 1, 9, 0, 5, 4}),
-				buffer.NewViewFromBytes([]byte{4, 3, 7, 1, 2, 123, 99}),
-			}),
-			initial: 77,
-			off:     7,
-			size:    11,
-			want:    33896,
+			name: "ThreeViews",
+			data: [][]byte{
+				[]byte{77, 11, 33, 0, 55, 44},
+				[]byte{98, 1, 9, 0, 5, 4},
+				[]byte{4, 3, 7, 1, 2, 123, 99},
+			},
+			want: 34236,
 		},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			if got, want := header.ChecksumVVWithOffset(tc.vv, tc.initial, tc.off, tc.size), tc.want; got != want {
-				t.Errorf("header.ChecksumVVWithOffset(%v) = %v, want: %v", tc, got, tc.want)
+			var all bytes.Buffer
+			var c header.Checksumer
+			for _, b := range tc.data {
+				c.Add(b)
+				// Append to the buffer. We will check the checksum as a whole later.
+				if _, err := all.Write(b); err != nil {
+					t.Fatalf("all.Write(b) = _, %s; want _, nil", err)
+				}
+			}
+			if got, want := c.Checksum(), tc.want; got != want {
+				t.Errorf("c.Checksum() = %d, want %d", got, want)
 			}
-			v := tc.vv.ToView()
-			v.TrimFront(tc.off)
-			v.CapLength(tc.size)
-			if got, want := header.Checksum(v, tc.initial), tc.want; got != want {
-				t.Errorf("header.Checksum(%v) = %v, want: %v", tc, got, tc.want)
+			if got, want := header.Checksum(all.Bytes(), 0 /* initial */), tc.want; got != want {
+				t.Errorf("Checksum(flatten tc.data) = %d, want %d", got, want)
 			}
 		})
 	}
@@ -228,7 +215,7 @@ func TestICMPv4Checksum(t *testing.T) {
 	h.SetChecksum(want)
 
 	testICMPChecksum(t, h.Checksum, func() uint16 {
-		return header.ICMPv4Checksum(h, vv)
+		return header.ICMPv4Checksum(h, header.ChecksumVV(vv, 0))
 	}, want, fmt.Sprintf("header: {% x} data {% x}", h, vv.ToView()))
 }
 
@@ -260,6 +247,12 @@ func TestICMPv6Checksum(t *testing.T) {
 	h.SetChecksum(want)
 
 	testICMPChecksum(t, h.Checksum, func() uint16 {
-		return header.ICMPv6Checksum(h, src, dst, vv)
+		return header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
+			Header:      h,
+			Src:         src,
+			Dst:         dst,
+			PayloadCsum: header.ChecksumVV(vv, 0),
+			PayloadLen:  vv.Size(),
+		})
 	}, want, fmt.Sprintf("header: {% x} data {% x}", h, vv.ToView()))
 }