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, 13 insertions, 4 deletions

diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go
index eca9750ab..668da623a 100644
--- a/pkg/tcpip/header/icmpv6.go
+++ b/pkg/tcpip/header/icmpv6.go
@@ -18,7 +18,6 @@ import (
 	"encoding/binary"
 
 	"gvisor.dev/gvisor/pkg/tcpip"
-	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 )
 
 // ICMPv6 represents an ICMPv6 header stored in a byte array.
@@ -262,12 +261,22 @@ func (b ICMPv6) Payload() []byte {
 	return b[ICMPv6PayloadOffset:]
 }
 
+// ICMPv6ChecksumParams contains parameters to calculate ICMPv6 checksum.
+type ICMPv6ChecksumParams struct {
+	Header      ICMPv6
+	Src         tcpip.Address
+	Dst         tcpip.Address
+	PayloadCsum uint16
+	PayloadLen  int
+}
+
 // ICMPv6Checksum calculates the ICMP checksum over the provided ICMPv6 header,
 // IPv6 src/dst addresses and the payload.
-func ICMPv6Checksum(h ICMPv6, src, dst tcpip.Address, vv buffer.VectorisedView) uint16 {
-	xsum := PseudoHeaderChecksum(ICMPv6ProtocolNumber, src, dst, uint16(len(h)+vv.Size()))
+func ICMPv6Checksum(params ICMPv6ChecksumParams) uint16 {
+	h := params.Header
 
-	xsum = ChecksumVV(vv, xsum)
+	xsum := PseudoHeaderChecksum(ICMPv6ProtocolNumber, params.Src, params.Dst, uint16(len(h)+params.PayloadLen))
+	xsum = ChecksumCombine(xsum, params.PayloadCsum)
 
 	// h[2:4] is the checksum itself, skip it to avoid checksumming the checksum.
 	xsum = Checksum(h[:2], xsum)