Remove buffer.Prependable.UsedBytes

It is the same as buffer.Prependable.View.

PiperOrigin-RevId: 213064166
Change-Id: Ib33b8a2c4da864209d9a0be0a1c113be10b520d3

pkg/tcpip/buffer/prependable.go

@@ -41,6 +41,17 @@ func NewPrependableFromView(v View) Prependable {
 	return Prependable{buf: v, usedIdx: 0}
 }
 
+// View returns a View of the backing buffer that contains all prepended
+// data so far.
+func (p Prependable) View() View {
+	return p.buf[p.usedIdx:]
+}
+
+// UsedLength returns the number of bytes used so far.
+func (p Prependable) UsedLength() int {
+	return len(p.buf) - p.usedIdx
+}
+
 // Prepend reserves the requested space in front of the buffer, returning a
 // slice that represents the reserved space.
 func (p *Prependable) Prepend(size int) []byte {
@@ -49,24 +60,5 @@ func (p *Prependable) Prepend(size int) []byte {
 	}
 
 	p.usedIdx -= size
-	return p.buf[p.usedIdx:][:size:size]
-}
-
-// View returns a View of the backing buffer that contains all prepended
-// data so far.
-func (p Prependable) View() View {
-	v := p.buf
-	v.TrimFront(p.usedIdx)
-	return v
-}
-
-// UsedBytes returns a slice of the backing buffer that contains all prepended
-// data so far.
-func (p Prependable) UsedBytes() []byte {
-	return p.buf[p.usedIdx:]
-}
-
-// UsedLength returns the number of bytes used so far.
-func (p Prependable) UsedLength() int {
-	return len(p.buf) - p.usedIdx
+	return p.View()[:size:size]
 }

pkg/tcpip/link/fdbased/endpoint.go

@@ -178,10 +178,10 @@ func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload b
 	}
 
 	if payload.Size() == 0 {
-		return rawfile.NonBlockingWrite(e.fd, hdr.UsedBytes())
+		return rawfile.NonBlockingWrite(e.fd, hdr.View())
 	}
 
-	return rawfile.NonBlockingWrite2(e.fd, hdr.UsedBytes(), payload.ToView())
+	return rawfile.NonBlockingWrite2(e.fd, hdr.View(), payload.ToView())
 }
 
 func (e *endpoint) capViews(n int, buffers []int) int {

pkg/tcpip/link/fdbased/endpoint_test.go

@@ -17,6 +17,7 @@
 package fdbased
 
 import (
+	"bytes"
 	"fmt"
 	"math/rand"
 	"reflect"
@@ -157,7 +158,7 @@ func TestWritePacket(t *testing.T) {
 				for i := range payload {
 					payload[i] = uint8(rand.Intn(256))
 				}
-				want := append(hdr.UsedBytes(), payload...)
+				want := append(hdr.View(), payload...)
 				if err := c.ep.WritePacket(r, hdr, payload.ToVectorisedView(), proto); err != nil {
 					t.Fatalf("WritePacket failed: %v", err)
 				}
@@ -188,7 +189,7 @@ func TestWritePacket(t *testing.T) {
 				if len(b) != len(want) {
 					t.Fatalf("Read returned %v bytes, want %v", len(b), len(want))
 				}
-				if !reflect.DeepEqual(b, want) {
+				if !bytes.Equal(b, want) {
 					t.Fatalf("Read returned %x, want %x", b, want)
 				}
 			})

pkg/tcpip/link/sharedmem/sharedmem.go

@@ -196,7 +196,7 @@ func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload b
 	v := payload.ToView()
 	// Transmit the packet.
 	e.mu.Lock()
-	ok := e.tx.transmit(hdr.UsedBytes(), v)
+	ok := e.tx.transmit(hdr.View(), v)
 	e.mu.Unlock()
 
 	if !ok {

pkg/tcpip/link/sniffer/sniffer.go

@@ -190,10 +190,10 @@ func (e *endpoint) LinkAddress() tcpip.LinkAddress {
 // the request to the lower endpoint.
 func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
 	if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil {
-		logPacket("send", protocol, hdr.UsedBytes())
+		logPacket("send", protocol, hdr.View())
 	}
 	if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 {
-		hdrBuf := hdr.UsedBytes()
+		hdrBuf := hdr.View()
 		length := len(hdrBuf) + payload.Size()
 		if length > int(e.maxPCAPLen) {
 			length = int(e.maxPCAPLen)

pkg/tcpip/network/ip_test.go

@@ -151,13 +151,13 @@ func (t *testObject) WritePacket(_ *stack.Route, hdr buffer.Prependable, payload
 	var dstAddr tcpip.Address
 
 	if t.v4 {
-		h := header.IPv4(hdr.UsedBytes())
+		h := header.IPv4(hdr.View())
 		prot = tcpip.TransportProtocolNumber(h.Protocol())
 		srcAddr = h.SourceAddress()
 		dstAddr = h.DestinationAddress()
 
 	} else {
-		h := header.IPv6(hdr.UsedBytes())
+		h := header.IPv6(hdr.View())
 		prot = tcpip.TransportProtocolNumber(h.NextHeader())
 		srcAddr = h.SourceAddress()
 		dstAddr = h.DestinationAddress()

pkg/tcpip/network/ipv6/icmp_test.go

@@ -187,7 +187,7 @@ func TestLinkResolution(t *testing.T) {
 	pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6EchoMinimumSize))
 	pkt.SetType(header.ICMPv6EchoRequest)
 	pkt.SetChecksum(icmpChecksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{}))
-	payload := tcpip.SlicePayload(hdr.UsedBytes())
+	payload := tcpip.SlicePayload(hdr.View())
 
 	// We can't send our payload directly over the route because that
 	// doesn't provoke NDP discovery.