First Commit of Voltha-Go-Controller from Radisys
Change-Id: I8e2e908e7ab09a4fe3d86849da18b6d69dcf4ab0
diff --git a/vendor/github.com/google/gopacket/layers/tcpip.go b/vendor/github.com/google/gopacket/layers/tcpip.go
new file mode 100644
index 0000000..64ba51c
--- /dev/null
+++ b/vendor/github.com/google/gopacket/layers/tcpip.go
@@ -0,0 +1,104 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+// Copyright 2009-2011 Andreas Krennmair. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+package layers
+
+import (
+ "errors"
+ "fmt"
+
+ "github.com/google/gopacket"
+)
+
+// Checksum computation for TCP/UDP.
+type tcpipchecksum struct {
+ pseudoheader tcpipPseudoHeader
+}
+
+type tcpipPseudoHeader interface {
+ pseudoheaderChecksum() (uint32, error)
+}
+
+func (ip *IPv4) pseudoheaderChecksum() (csum uint32, err error) {
+ if err := ip.AddressTo4(); err != nil {
+ return 0, err
+ }
+ csum += (uint32(ip.SrcIP[0]) + uint32(ip.SrcIP[2])) << 8
+ csum += uint32(ip.SrcIP[1]) + uint32(ip.SrcIP[3])
+ csum += (uint32(ip.DstIP[0]) + uint32(ip.DstIP[2])) << 8
+ csum += uint32(ip.DstIP[1]) + uint32(ip.DstIP[3])
+ return csum, nil
+}
+
+func (ip *IPv6) pseudoheaderChecksum() (csum uint32, err error) {
+ if err := ip.AddressTo16(); err != nil {
+ return 0, err
+ }
+ for i := 0; i < 16; i += 2 {
+ csum += uint32(ip.SrcIP[i]) << 8
+ csum += uint32(ip.SrcIP[i+1])
+ csum += uint32(ip.DstIP[i]) << 8
+ csum += uint32(ip.DstIP[i+1])
+ }
+ return csum, nil
+}
+
+// Calculate the TCP/IP checksum defined in rfc1071. The passed-in csum is any
+// initial checksum data that's already been computed.
+func tcpipChecksum(data []byte, csum uint32) uint16 {
+ // to handle odd lengths, we loop to length - 1, incrementing by 2, then
+ // handle the last byte specifically by checking against the original
+ // length.
+ length := len(data) - 1
+ for i := 0; i < length; i += 2 {
+ // For our test packet, doing this manually is about 25% faster
+ // (740 ns vs. 1000ns) than doing it by calling binary.BigEndian.Uint16.
+ csum += uint32(data[i]) << 8
+ csum += uint32(data[i+1])
+ }
+ if len(data)%2 == 1 {
+ csum += uint32(data[length]) << 8
+ }
+ for csum > 0xffff {
+ csum = (csum >> 16) + (csum & 0xffff)
+ }
+ return ^uint16(csum)
+}
+
+// computeChecksum computes a TCP or UDP checksum. headerAndPayload is the
+// serialized TCP or UDP header plus its payload, with the checksum zero'd
+// out. headerProtocol is the IP protocol number of the upper-layer header.
+func (c *tcpipchecksum) computeChecksum(headerAndPayload []byte, headerProtocol IPProtocol) (uint16, error) {
+ if c.pseudoheader == nil {
+ return 0, errors.New("TCP/IP layer 4 checksum cannot be computed without network layer... call SetNetworkLayerForChecksum to set which layer to use")
+ }
+ length := uint32(len(headerAndPayload))
+ csum, err := c.pseudoheader.pseudoheaderChecksum()
+ if err != nil {
+ return 0, err
+ }
+ csum += uint32(headerProtocol)
+ csum += length & 0xffff
+ csum += length >> 16
+ return tcpipChecksum(headerAndPayload, csum), nil
+}
+
+// SetNetworkLayerForChecksum tells this layer which network layer is wrapping it.
+// This is needed for computing the checksum when serializing, since TCP/IP transport
+// layer checksums depends on fields in the IPv4 or IPv6 layer that contains it.
+// The passed in layer must be an *IPv4 or *IPv6.
+func (i *tcpipchecksum) SetNetworkLayerForChecksum(l gopacket.NetworkLayer) error {
+ switch v := l.(type) {
+ case *IPv4:
+ i.pseudoheader = v
+ case *IPv6:
+ i.pseudoheader = v
+ default:
+ return fmt.Errorf("cannot use layer type %v for tcp checksum network layer", l.LayerType())
+ }
+ return nil
+}