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netstack: Don't exclude length when a pseudo-header checksum is calculated

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This is a preparation for GSO changes (cl/234508902).

RELNOTES[gofers]: Refactor checksum code to include length, which
it already did, but in a convoluted way. Should be a no-op.

PiperOrigin-RevId: 240460794
Change-Id: I537381bc670b5a9f5d70a87aa3eb7252e8f5ace2
This commit is contained in:
Andrei Vagin
2019-03-26 17:15:13 -07:00
committed by Shentubot
parent 06ec97a3f8
commit 654e878abb
8 changed files with 30 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/tcpip/header/checksum.go
+12 -5
View File
@@ -17,6 +17,8 @@
package header
import (
"encoding/binary"
"gvisor.googlesource.com/gvisor/pkg/tcpip"
"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
)
@@ -76,12 +78,17 @@ func ChecksumCombine(a, b uint16) uint16 {
return uint16(v + v>>16)
}
// PseudoHeaderChecksum calculates the pseudo-header checksum for the
// given destination protocol and network address, ignoring the length
// field. Pseudo-headers are needed by transport layers when calculating
// their own checksum.
func PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, srcAddr tcpip.Address, dstAddr tcpip.Address) uint16 {
// PseudoHeaderChecksum calculates the pseudo-header checksum for the given
// destination protocol and network address. Pseudo-headers are needed by
// transport layers when calculating their own checksum.
func PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, srcAddr tcpip.Address, dstAddr tcpip.Address, totalLen uint16) uint16 {
xsum := Checksum([]byte(srcAddr), 0)
xsum = Checksum([]byte(dstAddr), xsum)
// Add the length portion of the checksum to the pseudo-checksum.
tmp := make([]byte, 2)
binary.BigEndian.PutUint16(tmp, totalLen)
xsum = Checksum(tmp, xsum)
return Checksum([]byte{0, uint8(protocol)}, xsum)
}
pkg/tcpip/header/tcp.go
+4 -11
View File
@@ -231,19 +231,12 @@ func (b TCP) SetChecksum(checksum uint16) {
binary.BigEndian.PutUint16(b[tcpChecksum:], checksum)
}
// CalculateChecksum calculates the checksum of the tcp segment given
// the totalLen and partialChecksum(descriptions below)
// totalLen is the total length of the segment
// CalculateChecksum calculates the checksum of the tcp segment.
// partialChecksum is the checksum of the network-layer pseudo-header
// (excluding the total length) and the checksum of the segment data.
func (b TCP) CalculateChecksum(partialChecksum uint16, totalLen uint16) uint16 {
// Add the length portion of the checksum to the pseudo-checksum.
tmp := make([]byte, 2)
binary.BigEndian.PutUint16(tmp, totalLen)
checksum := Checksum(tmp, partialChecksum)
// and the checksum of the segment data.
func (b TCP) CalculateChecksum(partialChecksum uint16) uint16 {
// Calculate the rest of the checksum.
return Checksum(b[:b.DataOffset()], checksum)
return Checksum(b[:b.DataOffset()], partialChecksum)
}
// Options returns a slice that holds the unparsed TCP options in the segment.
pkg/tcpip/header/udp.go
+4 -10
View File
@@ -94,17 +94,11 @@ func (b UDP) SetChecksum(checksum uint16) {
binary.BigEndian.PutUint16(b[udpChecksum:], checksum)
}
// CalculateChecksum calculates the checksum of the udp packet, given the total
// length of the packet and the checksum of the network-layer pseudo-header
// (excluding the total length) and the checksum of the payload.
func (b UDP) CalculateChecksum(partialChecksum uint16, totalLen uint16) uint16 {
// Add the length portion of the checksum to the pseudo-checksum.
tmp := make([]byte, 2)
binary.BigEndian.PutUint16(tmp, totalLen)
checksum := Checksum(tmp, partialChecksum)
// CalculateChecksum calculates the checksum of the udp packet, given the
// checksum of the network-layer pseudo-header and the checksum of the payload.
func (b UDP) CalculateChecksum(partialChecksum uint16) uint16 {
// Calculate the rest of the checksum.
return Checksum(b[:UDPMinimumSize], checksum)
return Checksum(b[:UDPMinimumSize], partialChecksum)
}
// Encode encodes all the fields of the udp header.
pkg/tcpip/stack/route.go
+2 -2
View File
@@ -88,8 +88,8 @@ func (r *Route) Stats() tcpip.Stats {
// PseudoHeaderChecksum forwards the call to the network endpoint's
// implementation.
func (r *Route) PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber) uint16 {
return header.PseudoHeaderChecksum(protocol, r.LocalAddress, r.RemoteAddress)
func (r *Route) PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, totalLen uint16) uint16 {
return header.PseudoHeaderChecksum(protocol, r.LocalAddress, r.RemoteAddress, totalLen)
}
// Capabilities returns the link-layer capabilities of the route.
pkg/tcpip/transport/tcp/connect.go
+2 -2
View File
@@ -589,10 +589,10 @@ func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.Vectorise
// Only calculate the checksum if offloading isn't supported.
if r.Capabilities()&stack.CapabilityChecksumOffload == 0 {
length := uint16(hdr.UsedLength() + data.Size())
xsum := r.PseudoHeaderChecksum(ProtocolNumber)
xsum := r.PseudoHeaderChecksum(ProtocolNumber, length)
xsum = header.ChecksumVV(data, xsum)
tcp.SetChecksum(^tcp.CalculateChecksum(xsum, length))
tcp.SetChecksum(^tcp.CalculateChecksum(xsum))
}
r.Stats().TCP.SegmentsSent.Increment()
pkg/tcpip/transport/tcp/testing/context/context.go
+2 -4
View File
@@ -332,9 +332,8 @@ func (c *Context) BuildSegment(payload []byte, h *Headers) buffer.VectorisedView
xsum = header.Checksum([]byte{0, uint8(tcp.ProtocolNumber)}, xsum)
// Calculate the TCP checksum and set it.
length := uint16(header.TCPMinimumSize + len(h.TCPOpts) + len(payload))
xsum = header.Checksum(payload, xsum)
t.SetChecksum(^t.CalculateChecksum(xsum, length))
t.SetChecksum(^t.CalculateChecksum(xsum))
// Inject packet.
return buf.ToVectorisedView()
@@ -487,9 +486,8 @@ func (c *Context) SendV6Packet(payload []byte, h *Headers) {
xsum = header.Checksum([]byte{0, uint8(tcp.ProtocolNumber)}, xsum)
// Calculate the TCP checksum and set it.
length := uint16(header.TCPMinimumSize + len(payload))
xsum = header.Checksum(payload, xsum)
t.SetChecksum(^t.CalculateChecksum(xsum, length))
t.SetChecksum(^t.CalculateChecksum(xsum))
// Inject packet.
c.linkEP.Inject(ipv6.ProtocolNumber, buf.ToVectorisedView())
pkg/tcpip/transport/udp/endpoint.go
+2 -2
View File
@@ -641,11 +641,11 @@ func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort u
// Only calculate the checksum if offloading isn't supported.
if r.Capabilities()&stack.CapabilityChecksumOffload == 0 {
xsum := r.PseudoHeaderChecksum(ProtocolNumber)
xsum := r.PseudoHeaderChecksum(ProtocolNumber, length)
for _, v := range data.Views() {
xsum = header.Checksum(v, xsum)
}
udp.SetChecksum(^udp.CalculateChecksum(xsum, length))
udp.SetChecksum(^udp.CalculateChecksum(xsum))
}
// Track count of packets sent.
pkg/tcpip/transport/udp/udp_test.go
+2 -4
View File
@@ -200,9 +200,8 @@ func (c *testContext) sendV6Packet(payload []byte, h *headers) {
xsum = header.Checksum([]byte{0, uint8(udp.ProtocolNumber)}, xsum)
// Calculate the UDP checksum and set it.
length := uint16(header.UDPMinimumSize + len(payload))
xsum = header.Checksum(payload, xsum)
u.SetChecksum(^u.CalculateChecksum(xsum, length))
u.SetChecksum(^u.CalculateChecksum(xsum))
// Inject packet.
c.linkEP.Inject(ipv6.ProtocolNumber, buf.ToVectorisedView())
@@ -239,9 +238,8 @@ func (c *testContext) sendPacket(payload []byte, h *headers) {
xsum = header.Checksum([]byte{0, uint8(udp.ProtocolNumber)}, xsum)
// Calculate the UDP checksum and set it.
length := uint16(header.UDPMinimumSize + len(payload))
xsum = header.Checksum(payload, xsum)
u.SetChecksum(^u.CalculateChecksum(xsum, length))
u.SetChecksum(^u.CalculateChecksum(xsum))
// Inject packet.
c.linkEP.Inject(ipv4.ProtocolNumber, buf.ToVectorisedView())