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

2 files changed, 6 insertions, 6 deletions

diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 807df2bb5..b519afed1 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -1227,7 +1227,7 @@ func verifyChecksum(hdr header.UDP, pkt *stack.PacketBuffer) bool {
 		(hdr.Checksum() != 0 || pkt.NetworkProtocolNumber == header.IPv6ProtocolNumber) {
 		netHdr := pkt.Network()
 		xsum := header.PseudoHeaderChecksum(ProtocolNumber, netHdr.DestinationAddress(), netHdr.SourceAddress(), hdr.Length())
-		for _, v := range pkt.Data.Views() {
+		for _, v := range pkt.Data().Views() {
 			xsum = header.Checksum(v, xsum)
 		}
 		return hdr.CalculateChecksum(xsum) == 0xffff
@@ -1240,7 +1240,7 @@ func verifyChecksum(hdr header.UDP, pkt *stack.PacketBuffer) bool {
 func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketBuffer) {
 	// Get the header then trim it from the view.
 	hdr := header.UDP(pkt.TransportHeader().View())
-	if int(hdr.Length()) > pkt.Data.Size()+header.UDPMinimumSize {
+	if int(hdr.Length()) > pkt.Data().Size()+header.UDPMinimumSize {
 		// Malformed packet.
 		e.stack.Stats().UDP.MalformedPacketsReceived.Increment()
 		e.stats.ReceiveErrors.MalformedPacketsReceived.Increment()
@@ -1287,10 +1287,10 @@ func (e *endpoint) HandlePacket(id stack.TransportEndpointID, pkt *stack.PacketB
 			Addr: id.LocalAddress,
 			Port: header.UDP(hdr).DestinationPort(),
 		},
+		data: pkt.Data().ExtractVV(),
 	}
-	packet.data = pkt.Data
 	e.rcvList.PushBack(packet)
-	e.rcvBufSize += pkt.Data.Size()
+	e.rcvBufSize += packet.data.Size()
 
 	// Save any useful information from the network header to the packet.
 	switch pkt.NetworkProtocolNumber {
@@ -1327,7 +1327,7 @@ func (e *endpoint) onICMPError(err tcpip.Error, transErr stack.TransportError, p
 	if e.SocketOptions().GetRecvError() {
 		// Linux passes the payload without the UDP header.
 		var payload []byte
-		udp := header.UDP(pkt.Data.ToView())
+		udp := header.UDP(pkt.Data().AsRange().ToOwnedView())
 		if len(udp) >= header.UDPMinimumSize {
 			payload = udp.Payload()
 		}
diff --git a/pkg/tcpip/transport/udp/protocol.go b/pkg/tcpip/transport/udp/protocol.go
index 427fdd0c9..1171aeb79 100644
--- a/pkg/tcpip/transport/udp/protocol.go
+++ b/pkg/tcpip/transport/udp/protocol.go
@@ -80,7 +80,7 @@ func (*protocol) ParsePorts(v buffer.View) (src, dst uint16, err tcpip.Error) {
 // protocol but don't match any existing endpoint.
 func (p *protocol) HandleUnknownDestinationPacket(id stack.TransportEndpointID, pkt *stack.PacketBuffer) stack.UnknownDestinationPacketDisposition {
 	hdr := header.UDP(pkt.TransportHeader().View())
-	if int(hdr.Length()) > pkt.Data.Size()+header.UDPMinimumSize {
+	if int(hdr.Length()) > pkt.Data().Size()+header.UDPMinimumSize {
 		p.stack.Stats().UDP.MalformedPacketsReceived.Increment()
 		return stack.UnknownDestinationPacketMalformed
 	}