Remove buffer.Prependable.UsedBytes

It is the same as buffer.Prependable.View.

PiperOrigin-RevId: 213064166
Change-Id: Ib33b8a2c4da864209d9a0be0a1c113be10b520d3

7 files changed, 22 insertions, 29 deletions

diff --git a/pkg/tcpip/buffer/prependable.go b/pkg/tcpip/buffer/prependable.go
index bca23ef68..c5dd2819f 100644
--- a/pkg/tcpip/buffer/prependable.go
+++ b/pkg/tcpip/buffer/prependable.go
@@ -41,28 +41,9 @@ func NewPrependableFromView(v View) Prependable {
 	return Prependable{buf: v, usedIdx: 0}
 }
 
-// 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 {
-	if size > p.usedIdx {
-		return nil
-	}
-
-	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:]
 }
 
@@ -70,3 +51,14 @@ func (p Prependable) UsedBytes() []byte {
 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 {
+	if size > p.usedIdx {
+		return nil
+	}
+
+	p.usedIdx -= size
+	return p.View()[:size:size]
+}
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index 0b0d6c1e2..40a10eb9b 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/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 {
diff --git a/pkg/tcpip/link/fdbased/endpoint_test.go b/pkg/tcpip/link/fdbased/endpoint_test.go
index f7890e031..411ad7832 100644
--- a/pkg/tcpip/link/fdbased/endpoint_test.go
+++ b/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)
 				}
 			})
diff --git a/pkg/tcpip/link/sharedmem/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go
index 887612957..5157f71e8 100644
--- a/pkg/tcpip/link/sharedmem/sharedmem.go
+++ b/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 {
diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go
index e6ce3ee13..bfb79fd57 100644
--- a/pkg/tcpip/link/sniffer/sniffer.go
+++ b/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)
diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go
index b381c7214..e3c7af1f9 100644
--- a/pkg/tcpip/network/ip_test.go
+++ b/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()
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index c48859be3..0a0563964 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/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.