| // 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. |
| 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 |
| } |