From 47515f475167ffa23267ca0b9d1b39e7907587d6 Mon Sep 17 00:00:00 2001 From: Ting-Yu Wang Date: Thu, 13 Aug 2020 13:07:03 -0700 Subject: Migrate to PacketHeader API for PacketBuffer. Formerly, when a packet is constructed or parsed, all headers are set by the client code. This almost always involved prepending to pk.Header buffer or trimming pk.Data portion. This is known to prone to bugs, due to the complexity and number of the invariants assumed across netstack to maintain. In the new PacketHeader API, client will call Push()/Consume() method to construct/parse an outgoing/incoming packet. All invariants, such as slicing and trimming, are maintained by the API itself. NewPacketBuffer() is introduced to create new PacketBuffer. Zero value is no longer valid. PacketBuffer now assumes the packet is a concatenation of following portions: * LinkHeader * NetworkHeader * TransportHeader * Data Any of them could be empty, or zero-length. PiperOrigin-RevId: 326507688 --- pkg/tcpip/transport/packet/endpoint.go | 35 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 18 deletions(-) (limited to 'pkg/tcpip/transport/packet') diff --git a/pkg/tcpip/transport/packet/endpoint.go b/pkg/tcpip/transport/packet/endpoint.go index df478115d..1b03ad6bb 100644 --- a/pkg/tcpip/transport/packet/endpoint.go +++ b/pkg/tcpip/transport/packet/endpoint.go @@ -433,9 +433,9 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress, // Push new packet into receive list and increment the buffer size. var packet packet // TODO(gvisor.dev/issue/173): Return network protocol. - if len(pkt.LinkHeader) > 0 { + if !pkt.LinkHeader().View().IsEmpty() { // Get info directly from the ethernet header. - hdr := header.Ethernet(pkt.LinkHeader) + hdr := header.Ethernet(pkt.LinkHeader().View()) packet.senderAddr = tcpip.FullAddress{ NIC: nicID, Addr: tcpip.Address(hdr.SourceAddress()), @@ -458,9 +458,14 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress, case tcpip.PacketHost: packet.data = pkt.Data case tcpip.PacketOutgoing: - // Strip Link Header from the Header. - pkt.Header = buffer.NewPrependableFromView(pkt.Header.View()[len(pkt.LinkHeader):]) - combinedVV := pkt.Header.View().ToVectorisedView() + // Strip Link Header. + var combinedVV buffer.VectorisedView + if v := pkt.NetworkHeader().View(); !v.IsEmpty() { + combinedVV.AppendView(v) + } + if v := pkt.TransportHeader().View(); !v.IsEmpty() { + combinedVV.AppendView(v) + } combinedVV.Append(pkt.Data) packet.data = combinedVV default: @@ -471,9 +476,8 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress, // Raw packets need their ethernet headers prepended before // queueing. var linkHeader buffer.View - var combinedVV buffer.VectorisedView if pkt.PktType != tcpip.PacketOutgoing { - if len(pkt.LinkHeader) == 0 { + if pkt.LinkHeader().View().IsEmpty() { // We weren't provided with an actual ethernet header, // so fake one. ethFields := header.EthernetFields{ @@ -485,19 +489,14 @@ func (ep *endpoint) HandlePacket(nicID tcpip.NICID, localAddr tcpip.LinkAddress, fakeHeader.Encode(ðFields) linkHeader = buffer.View(fakeHeader) } else { - linkHeader = append(buffer.View(nil), pkt.LinkHeader...) + linkHeader = append(buffer.View(nil), pkt.LinkHeader().View()...) } - combinedVV = linkHeader.ToVectorisedView() - } - if pkt.PktType == tcpip.PacketOutgoing { - // For outgoing packets the Link, Network and Transport - // headers are in the pkt.Header fields normally unless - // a Raw socket is in use in which case pkt.Header could - // be nil. - combinedVV.AppendView(pkt.Header.View()) + combinedVV := linkHeader.ToVectorisedView() + combinedVV.Append(pkt.Data) + packet.data = combinedVV + } else { + packet.data = buffer.NewVectorisedView(pkt.Size(), pkt.Views()) } - combinedVV.Append(pkt.Data) - packet.data = combinedVV } packet.timestampNS = ep.stack.Clock().NowNanoseconds() -- cgit v1.2.3