1 files changed, 74 insertions, 0 deletions
diff --git a/pkg/tcpip/header/eth.go b/pkg/tcpip/header/eth.go
new file mode 100644
index 000000000..76143f454
--- /dev/null
+++ b/pkg/tcpip/header/eth.go
@@ -0,0 +1,74 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package header
+
+import (
+	"encoding/binary"
+
+	"gvisor.googlesource.com/gvisor/pkg/tcpip"
+)
+
+const (
+	dstMAC  = 0
+	srcMAC  = 6
+	ethType = 12
+)
+
+// EthernetFields contains the fields of an ethernet frame header. It is used to
+// describe the fields of a frame that needs to be encoded.
+type EthernetFields struct {
+	// SrcAddr is the "MAC source" field of an ethernet frame header.
+	SrcAddr tcpip.LinkAddress
+
+	// DstAddr is the "MAC destination" field of an ethernet frame header.
+	DstAddr tcpip.LinkAddress
+
+	// Type is the "ethertype" field of an ethernet frame header.
+	Type tcpip.NetworkProtocolNumber
+}
+
+// Ethernet represents an ethernet frame header stored in a byte array.
+type Ethernet []byte
+
+const (
+	// EthernetMinimumSize is the minimum size of a valid ethernet frame.
+	EthernetMinimumSize = 14
+
+	// EthernetAddressSize is the size, in bytes, of an ethernet address.
+	EthernetAddressSize = 6
+)
+
+// SourceAddress returns the "MAC source" field of the ethernet frame header.
+func (b Ethernet) SourceAddress() tcpip.LinkAddress {
+	return tcpip.LinkAddress(b[srcMAC:][:EthernetAddressSize])
+}
+
+// DestinationAddress returns the "MAC destination" field of the ethernet frame
+// header.
+func (b Ethernet) DestinationAddress() tcpip.LinkAddress {
+	return tcpip.LinkAddress(b[dstMAC:][:EthernetAddressSize])
+}
+
+// Type returns the "ethertype" field of the ethernet frame header.
+func (b Ethernet) Type() tcpip.NetworkProtocolNumber {
+	return tcpip.NetworkProtocolNumber(binary.BigEndian.Uint16(b[ethType:]))
+}
+
+// Encode encodes all the fields of the ethernet frame header.
+func (b Ethernet) Encode(e *EthernetFields) {
+	binary.BigEndian.PutUint16(b[ethType:], uint16(e.Type))
+	copy(b[srcMAC:][:EthernetAddressSize], e.SrcAddr)
+	copy(b[dstMAC:][:EthernetAddressSize], e.DstAddr)
+}