[chore] Validate/set account domain (#619)

* add miekg/dns dependency

* set/validate accountDomain

vendor/golang.org/x/net/bpf/asm.go

@@ -0,0 +1,41 @@
+// 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
+
+import "fmt"
+
+// Assemble converts insts into raw instructions suitable for loading
+// into a BPF virtual machine.
+//
+// Currently, no optimization is attempted, the assembled program flow
+// is exactly as provided.
+func Assemble(insts []Instruction) ([]RawInstruction, error) {
+	ret := make([]RawInstruction, len(insts))
+	var err error
+	for i, inst := range insts {
+		ret[i], err = inst.Assemble()
+		if err != nil {
+			return nil, fmt.Errorf("assembling instruction %d: %s", i+1, err)
+		}
+	}
+	return ret, nil
+}
+
+// Disassemble attempts to parse raw back into
+// Instructions. Unrecognized RawInstructions are assumed to be an
+// extension not implemented by this package, and are passed through
+// unchanged to the output. The allDecoded value reports whether insts
+// contains no RawInstructions.
+func Disassemble(raw []RawInstruction) (insts []Instruction, allDecoded bool) {
+	insts = make([]Instruction, len(raw))
+	allDecoded = true
+	for i, r := range raw {
+		insts[i] = r.Disassemble()
+		if _, ok := insts[i].(RawInstruction); ok {
+			allDecoded = false
+		}
+	}
+	return insts, allDecoded
+}