1 files changed, 54 insertions, 0 deletions
diff --git a/pkg/tcpip/packet_buffer.go b/pkg/tcpip/packet_buffer.go
new file mode 100644
index 000000000..10b04239d
--- /dev/null
+++ b/pkg/tcpip/packet_buffer.go
@@ -0,0 +1,54 @@
+// Copyright 2019 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 tcpip
+
+import "gvisor.dev/gvisor/pkg/tcpip/buffer"
+
+// A PacketBuffer contains all the data of a network packet.
+//
+// As a PacketBuffer traverses up the stack, it may be necessary to pass it to
+// multiple endpoints. Clone() should be called in such cases so that
+// modifications to the Data field do not affect other copies.
+//
+// +stateify savable
+type PacketBuffer struct {
+	// Data holds the payload of the packet. For inbound packets, it also
+	// holds the headers, which are consumed as the packet moves up the
+	// stack. Headers are guaranteed not to be split across views.
+	//
+	// The bytes backing Data are immutable, but Data itself may be trimmed
+	// or otherwise modified.
+	Data buffer.VectorisedView
+
+	// The bytes backing these views are immutable. Each field may be nil
+	// if either it has not been set yet or no such header exists (e.g.
+	// packets sent via loopback may not have a link header).
+	//
+	// These fields may be Views into other Views. SR dosen't support this,
+	// so deep copies are necessary in some cases.
+	LinkHeader      buffer.View
+	NetworkHeader   buffer.View
+	TransportHeader buffer.View
+}
+
+// Clone makes a copy of pk. It clones the Data field, which creates a new
+// VectorisedView but does not deep copy the underlying bytes.
+func (pk PacketBuffer) Clone() PacketBuffer {
+	return PacketBuffer{
+		Data:            pk.Data.Clone(nil),
+		LinkHeader:      pk.LinkHeader,
+		NetworkHeader:   pk.NetworkHeader,
+		TransportHeader: pk.TransportHeader,
+	}
+}