Work on #61: Add support for ICMP

+ Update dependencies

vendor/golang.org/x/net/icmp/timeexceeded.go

@@ -0,0 +1,57 @@
+// Copyright 2014 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 icmp
+
+import (
+	"golang.org/x/net/internal/iana"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+// A TimeExceeded represents an ICMP time exceeded message body.
+type TimeExceeded struct {
+	Data       []byte      // data, known as original datagram field
+	Extensions []Extension // extensions
+}
+
+// Len implements the Len method of MessageBody interface.
+func (p *TimeExceeded) Len(proto int) int {
+	if p == nil {
+		return 0
+	}
+	l, _ := multipartMessageBodyDataLen(proto, true, p.Data, p.Extensions)
+	return l
+}
+
+// Marshal implements the Marshal method of MessageBody interface.
+func (p *TimeExceeded) Marshal(proto int) ([]byte, error) {
+	var typ Type
+	switch proto {
+	case iana.ProtocolICMP:
+		typ = ipv4.ICMPTypeTimeExceeded
+	case iana.ProtocolIPv6ICMP:
+		typ = ipv6.ICMPTypeTimeExceeded
+	default:
+		return nil, errInvalidProtocol
+	}
+	if !validExtensions(typ, p.Extensions) {
+		return nil, errInvalidExtension
+	}
+	return marshalMultipartMessageBody(proto, true, p.Data, p.Extensions)
+}
+
+// parseTimeExceeded parses b as an ICMP time exceeded message body.
+func parseTimeExceeded(proto int, typ Type, b []byte) (MessageBody, error) {
+	if len(b) < 4 {
+		return nil, errMessageTooShort
+	}
+	p := &TimeExceeded{}
+	var err error
+	p.Data, p.Extensions, err = parseMultipartMessageBody(proto, typ, b)
+	if err != nil {
+		return nil, err
+	}
+	return p, nil
+}