a8a12cafc9
External ICMP does not necessarily work. It typically does, but not always. Last week, for a day or two, ICMP traffic was dropped by Google. So now we use ICMP only for network equipment targets (default gateway), and instead use TCP for external connectivity checks. fixes #77
122 lines
2.3 KiB
Go
122 lines
2.3 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package diag
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import (
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"net"
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)
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type tcp4 struct {
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children []Node
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addr string
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}
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func (d *tcp4) String() string {
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return "tcp4: " + d.addr
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}
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func (d *tcp4) Then(t Node) Node {
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d.children = append(d.children, t)
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return d
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}
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func (d *tcp4) Children() []Node {
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return d.children
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}
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func (d *tcp4) Evaluate() (string, error) {
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conn, err := net.Dial("tcp4", d.addr)
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if err != nil {
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return "", err
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}
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defer conn.Close()
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return "connection established", nil
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}
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// TCP4 returns a Node which succeeds when the specified address accepts a TCPv4
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// connection.
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func TCP4(addr string) Node {
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return &tcp4{addr: addr}
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}
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type tcp6 struct {
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children []Node
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ifname string
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addr string
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}
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func (d *tcp6) String() string {
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return "tcp6: " + d.addr
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}
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func (d *tcp6) Then(t Node) Node {
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d.children = append(d.children, t)
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return d
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}
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func (d *tcp6) Children() []Node {
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return d.children
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}
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func (d *tcp6) Evaluate() (string, error) {
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var dialer net.Dialer
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if d.ifname != "" {
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iface, err := net.InterfaceByName(d.ifname)
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if err != nil {
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return "", err
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}
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addrs, err := iface.Addrs()
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if err != nil {
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return "", err
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}
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for _, addr := range addrs {
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ipnet, ok := addr.(*net.IPNet)
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if !ok {
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continue
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}
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if ipnet.IP.To4() != nil {
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continue // skip IPv4 addresses
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}
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if !global.Contains(ipnet.IP) {
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continue // skip local IPv6 addresses
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}
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dialer.LocalAddr = &net.TCPAddr{
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IP: ipnet.IP,
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}
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break
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}
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}
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conn, err := dialer.Dial("tcp6", d.addr)
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if err != nil {
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return "", err
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}
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defer conn.Close()
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return "connection established", nil
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}
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// TCP6 returns a Node which succeeds when the specified address accepts a TCPv6
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// connection.
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func TCP6(ifname, addr string) Node {
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return &tcp6{
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ifname: ifname,
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addr: addr,
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}
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}
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