diff options
Diffstat (limited to 'pkg/tcpip/link/fdbased/endpoint.go')
| -rw-r--r-- | pkg/tcpip/link/fdbased/endpoint.go | 100 |
1 files changed, 70 insertions, 30 deletions
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go index 87c8ab1fc..20f379ab0 100644 --- a/pkg/tcpip/link/fdbased/endpoint.go +++ b/pkg/tcpip/link/fdbased/endpoint.go @@ -47,6 +47,30 @@ var BufConfig = []int{128, 256, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768} // NetworkDispatcher. type linkDispatcher func() (bool, *tcpip.Error) +// PacketDispatchMode are the various supported methods of receiving and +// dispatching packets from the underlying FD. +type PacketDispatchMode int + +const ( + // Readv is the default dispatch mode and is the least performant of the + // dispatch options but the one that is supported by all underlying FD + // types. + Readv PacketDispatchMode = iota + // RecvMMsg enables use of recvmmsg() syscall instead of readv() to + // read inbound packets. This reduces # of syscalls needed to process + // packets. + // + // NOTE: recvmmsg() is only supported for sockets, so if the underlying + // FD is not a socket then the code will still fall back to the readv() + // path. + RecvMMsg + // PacketMMap enables use of PACKET_RX_RING to receive packets from the + // NIC. PacketMMap requires that the underlying FD be an AF_PACKET. The + // primary use-case for this is runsc which uses an AF_PACKET FD to + // receive packets from the veth device. + PacketMMap +) + type endpoint struct { // fd is the file descriptor used to send and receive packets. fd int @@ -68,9 +92,11 @@ type endpoint struct { // its end of the communication pipe. closed func(*tcpip.Error) - views [][]buffer.View - iovecs [][]syscall.Iovec - msgHdrs []rawfile.MMsgHdr + views [][]buffer.View + iovecs [][]syscall.Iovec + // msgHdrs is only used by the RecvMMsg dispatcher. + msgHdrs []rawfile.MMsgHdr + inboundDispatcher linkDispatcher dispatcher stack.NetworkDispatcher @@ -79,28 +105,31 @@ type endpoint struct { // endpoint (false). handleLocal bool - // useRecvMMsg enables use of recvmmsg() syscall instead of readv() to - // read inbound packets. This reduces # of syscalls needed to process - // packets. - // - // NOTE: recvmmsg() is only supported for sockets, so if the underlying - // FD is not a socket then the code will still fall back to the readv() - // path. - useRecvMMsg bool + // packetDispatchMode controls the packet dispatcher used by this + // endpoint. + packetDispatchMode PacketDispatchMode + + // ringBuffer is only used when PacketMMap dispatcher is used and points + // to the start of the mmapped PACKET_RX_RING buffer. + ringBuffer []byte + + // ringOffset is the current offset into the ring buffer where the next + // inbound packet will be placed by the kernel. + ringOffset int } // Options specify the details about the fd-based endpoint to be created. type Options struct { - FD int - MTU uint32 - EthernetHeader bool - ChecksumOffload bool - ClosedFunc func(*tcpip.Error) - Address tcpip.LinkAddress - SaveRestore bool - DisconnectOk bool - HandleLocal bool - UseRecvMMsg bool + FD int + MTU uint32 + EthernetHeader bool + ChecksumOffload bool + ClosedFunc func(*tcpip.Error) + Address tcpip.LinkAddress + SaveRestore bool + DisconnectOk bool + HandleLocal bool + PacketDispatchMode PacketDispatchMode } // New creates a new fd-based endpoint. @@ -133,21 +162,31 @@ func New(opts *Options) tcpip.LinkEndpointID { } e := &endpoint{ - fd: opts.FD, - mtu: opts.MTU, - caps: caps, - closed: opts.ClosedFunc, - addr: opts.Address, - hdrSize: hdrSize, - handleLocal: opts.HandleLocal, - useRecvMMsg: opts.UseRecvMMsg, + fd: opts.FD, + mtu: opts.MTU, + caps: caps, + closed: opts.ClosedFunc, + addr: opts.Address, + hdrSize: hdrSize, + handleLocal: opts.HandleLocal, + packetDispatchMode: opts.PacketDispatchMode, + } + + if isSocketFD(opts.FD) && e.packetDispatchMode == PacketMMap { + if err := e.setupPacketRXRing(); err != nil { + // TODO: replace panic with an error return. + panic(fmt.Sprintf("e.setupPacketRXRing failed: %v", err)) + } + e.inboundDispatcher = e.packetMMapDispatch + return stack.RegisterLinkEndpoint(e) } + // For non-socket FDs we read one packet a time (e.g. TAP devices) msgsPerRecv := 1 e.inboundDispatcher = e.dispatch // If the provided FD is a socket then we optimize packet reads by // using recvmmsg() instead of read() to read packets in a batch. - if isSocketFD(opts.FD) && e.useRecvMMsg { + if isSocketFD(opts.FD) && e.packetDispatchMode == RecvMMsg { e.inboundDispatcher = e.recvMMsgDispatch msgsPerRecv = MaxMsgsPerRecv } @@ -165,6 +204,7 @@ func New(opts *Options) tcpip.LinkEndpointID { e.msgHdrs[i].Msg.Iov = &e.iovecs[i][0] e.msgHdrs[i].Msg.Iovlen = uint64(len(BufConfig)) } + return stack.RegisterLinkEndpoint(e) } |