Merge pull request #1 from google/master

catch up

1 files changed, 78 insertions, 0 deletions

diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
new file mode 100644
index 000000000..7d36f8e84
--- /dev/null
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -0,0 +1,78 @@
+// 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 stack
+
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"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.
+type PacketBuffer struct {
+	// PacketBufferEntry is used to build an intrusive list of
+	// PacketBuffers.
+	PacketBufferEntry
+
+	// 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
+
+	// Header holds the headers of outbound packets. As a packet is passed
+	// down the stack, each layer adds to Header. Note that forwarded
+	// packets don't populate Headers on their way out -- their headers and
+	// payload are never parsed out and remain in Data.
+	//
+	// TODO(gvisor.dev/issue/170): Forwarded packets don't currently
+	// populate Header, but should. This will be doable once early parsing
+	// (https://github.com/google/gvisor/pull/1995) is supported.
+	Header buffer.Prependable
+
+	// These fields are used by both inbound and outbound packets. They
+	// typically overlap with the Data and Header fields.
+	//
+	// 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 slices (either Data or Header).
+	// SR dosen't support this, so deep copies are necessary in some cases.
+	LinkHeader      buffer.View
+	NetworkHeader   buffer.View
+	TransportHeader buffer.View
+
+	// Hash is the transport layer hash of this packet. A value of zero
+	// indicates no valid hash has been set.
+	Hash uint32
+
+	// Owner is implemented by task to get the uid and gid.
+	// Only set for locally generated packets.
+	Owner tcpip.PacketOwner
+}
+
+// Clone makes a copy of pk. It clones the Data field, which creates a new
+// VectorisedView but does not deep copy the underlying bytes.
+//
+// Clone also does not deep copy any of its other fields.
+func (pk PacketBuffer) Clone() PacketBuffer {
+	pk.Data = pk.Data.Clone(nil)
+	return pk
+}