From 621e49bb465f500cc46d47e39e828cf76d6381d7 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Tue, 24 Jul 2018 14:35:44 +0200 Subject: update vendor --- vendor/golang.org/x/net/bpf/vm_bpf_test.go | 192 +++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 vendor/golang.org/x/net/bpf/vm_bpf_test.go (limited to 'vendor/golang.org/x/net/bpf/vm_bpf_test.go') diff --git a/vendor/golang.org/x/net/bpf/vm_bpf_test.go b/vendor/golang.org/x/net/bpf/vm_bpf_test.go new file mode 100644 index 0000000..77fa8fe --- /dev/null +++ b/vendor/golang.org/x/net/bpf/vm_bpf_test.go @@ -0,0 +1,192 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package bpf_test + +import ( + "net" + "runtime" + "testing" + "time" + + "golang.org/x/net/bpf" + "golang.org/x/net/ipv4" +) + +// A virtualMachine is a BPF virtual machine which can process an +// input packet against a BPF program and render a verdict. +type virtualMachine interface { + Run(in []byte) (int, error) +} + +// canUseOSVM indicates if the OS BPF VM is available on this platform. +func canUseOSVM() bool { + // OS BPF VM can only be used on platforms where x/net/ipv4 supports + // attaching a BPF program to a socket. + switch runtime.GOOS { + case "linux": + return true + } + + return false +} + +// All BPF tests against both the Go VM and OS VM are assumed to +// be used with a UDP socket. As a result, the entire contents +// of a UDP datagram is sent through the BPF program, but only +// the body after the UDP header will ever be returned in output. + +// testVM sets up a Go BPF VM, and if available, a native OS BPF VM +// for integration testing. +func testVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func(), error) { + goVM, err := bpf.NewVM(filter) + if err != nil { + // Some tests expect an error, so this error must be returned + // instead of fatally exiting the test + return nil, nil, err + } + + mvm := &multiVirtualMachine{ + goVM: goVM, + + t: t, + } + + // If available, add the OS VM for tests which verify that both the Go + // VM and OS VM have exactly the same output for the same input program + // and packet. + done := func() {} + if canUseOSVM() { + osVM, osVMDone := testOSVM(t, filter) + done = func() { osVMDone() } + mvm.osVM = osVM + } + + return mvm, done, nil +} + +// udpHeaderLen is the length of a UDP header. +const udpHeaderLen = 8 + +// A multiVirtualMachine is a virtualMachine which can call out to both the Go VM +// and the native OS VM, if the OS VM is available. +type multiVirtualMachine struct { + goVM virtualMachine + osVM virtualMachine + + t *testing.T +} + +func (mvm *multiVirtualMachine) Run(in []byte) (int, error) { + if len(in) < udpHeaderLen { + mvm.t.Fatalf("input must be at least length of UDP header (%d), got: %d", + udpHeaderLen, len(in)) + } + + // All tests have a UDP header as part of input, because the OS VM + // packets always will. For the Go VM, this output is trimmed before + // being sent back to tests. + goOut, goErr := mvm.goVM.Run(in) + if goOut >= udpHeaderLen { + goOut -= udpHeaderLen + } + + // If Go output is larger than the size of the packet, packet filtering + // interop tests must trim the output bytes to the length of the packet. + // The BPF VM should not do this on its own, as other uses of it do + // not trim the output byte count. + trim := len(in) - udpHeaderLen + if goOut > trim { + goOut = trim + } + + // When the OS VM is not available, process using the Go VM alone + if mvm.osVM == nil { + return goOut, goErr + } + + // The OS VM will apply its own UDP header, so remove the pseudo header + // that the Go VM needs. + osOut, err := mvm.osVM.Run(in[udpHeaderLen:]) + if err != nil { + mvm.t.Fatalf("error while running OS VM: %v", err) + } + + // Verify both VMs return same number of bytes + var mismatch bool + if goOut != osOut { + mismatch = true + mvm.t.Logf("output byte count does not match:\n- go: %v\n- os: %v", goOut, osOut) + } + + if mismatch { + mvm.t.Fatal("Go BPF and OS BPF packet outputs do not match") + } + + return goOut, goErr +} + +// An osVirtualMachine is a virtualMachine which uses the OS's BPF VM for +// processing BPF programs. +type osVirtualMachine struct { + l net.PacketConn + s net.Conn +} + +// testOSVM creates a virtualMachine which uses the OS's BPF VM by injecting +// packets into a UDP listener with a BPF program attached to it. +func testOSVM(t *testing.T, filter []bpf.Instruction) (virtualMachine, func()) { + l, err := net.ListenPacket("udp4", "127.0.0.1:0") + if err != nil { + t.Fatalf("failed to open OS VM UDP listener: %v", err) + } + + prog, err := bpf.Assemble(filter) + if err != nil { + t.Fatalf("failed to compile BPF program: %v", err) + } + + p := ipv4.NewPacketConn(l) + if err = p.SetBPF(prog); err != nil { + t.Fatalf("failed to attach BPF program to listener: %v", err) + } + + s, err := net.Dial("udp4", l.LocalAddr().String()) + if err != nil { + t.Fatalf("failed to dial connection to listener: %v", err) + } + + done := func() { + _ = s.Close() + _ = l.Close() + } + + return &osVirtualMachine{ + l: l, + s: s, + }, done +} + +// Run sends the input bytes into the OS's BPF VM and returns its verdict. +func (vm *osVirtualMachine) Run(in []byte) (int, error) { + go func() { + _, _ = vm.s.Write(in) + }() + + vm.l.SetDeadline(time.Now().Add(50 * time.Millisecond)) + + var b [512]byte + n, _, err := vm.l.ReadFrom(b[:]) + if err != nil { + // A timeout indicates that BPF filtered out the packet, and thus, + // no input should be returned. + if nerr, ok := err.(net.Error); ok && nerr.Timeout() { + return n, nil + } + + return n, err + } + + return n, nil +} -- cgit v1.2.3