Hulk did something

[bytom/vapor.git] / vendor / golang.org / x / net / ipv4 / bpf_test.go

diff --git a/vendor/golang.org/x/net/ipv4/bpf_test.go b/vendor/golang.org/x/net/ipv4/bpf_test.go
new file mode 100644 (file)
index 0000000..b44da90
--- /dev/null
+++ b/vendor/golang.org/x/net/ipv4/bpf_test.go
@@ -0,0 +1,93 @@
+// 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 ipv4_test
+
+import (
+       "net"
+       "runtime"
+       "testing"
+       "time"
+
+       "golang.org/x/net/bpf"
+       "golang.org/x/net/ipv4"
+)
+
+func TestBPF(t *testing.T) {
+       if runtime.GOOS != "linux" {
+               t.Skipf("not supported on %s", runtime.GOOS)
+       }
+
+       l, err := net.ListenPacket("udp4", "127.0.0.1:0")
+       if err != nil {
+               t.Fatal(err)
+       }
+       defer l.Close()
+
+       p := ipv4.NewPacketConn(l)
+
+       // This filter accepts UDP packets whose first payload byte is
+       // even.
+       prog, err := bpf.Assemble([]bpf.Instruction{
+               // Load the first byte of the payload (skipping UDP header).
+               bpf.LoadAbsolute{Off: 8, Size: 1},
+               // Select LSB of the byte.
+               bpf.ALUOpConstant{Op: bpf.ALUOpAnd, Val: 1},
+               // Byte is even?
+               bpf.JumpIf{Cond: bpf.JumpEqual, Val: 0, SkipFalse: 1},
+               // Accept.
+               bpf.RetConstant{Val: 4096},
+               // Ignore.
+               bpf.RetConstant{Val: 0},
+       })
+       if err != nil {
+               t.Fatalf("compiling BPF: %s", err)
+       }
+
+       if err = p.SetBPF(prog); err != nil {
+               t.Fatalf("attaching filter to Conn: %s", err)
+       }
+
+       s, err := net.Dial("udp4", l.LocalAddr().String())
+       if err != nil {
+               t.Fatal(err)
+       }
+       defer s.Close()
+       go func() {
+               for i := byte(0); i < 10; i++ {
+                       s.Write([]byte{i})
+               }
+       }()
+
+       l.SetDeadline(time.Now().Add(2 * time.Second))
+       seen := make([]bool, 5)
+       for {
+               var b [512]byte
+               n, _, err := l.ReadFrom(b[:])
+               if err != nil {
+                       t.Fatalf("reading from listener: %s", err)
+               }
+               if n != 1 {
+                       t.Fatalf("unexpected packet length, want 1, got %d", n)
+               }
+               if b[0] >= 10 {
+                       t.Fatalf("unexpected byte, want 0-9, got %d", b[0])
+               }
+               if b[0]%2 != 0 {
+                       t.Fatalf("got odd byte %d, wanted only even bytes", b[0])
+               }
+               seen[b[0]/2] = true
+
+               seenAll := true
+               for _, v := range seen {
+                       if !v {
+                               seenAll = false
+                               break
+                       }
+               }
+               if seenAll {
+                       break
+               }
+       }
+}