node_exporter/vendor/golang.org/x/net/ipv4/icmp.go
Leonid Evdokimov c169b4b1c5 Add metrics from SNTPv4 packet to ntp collector & add ntpd sanity check (#655)
* Add metrics from SNTPv4 packet to ntp collector & add ntpd sanity check

1. Checking local clock against remote NTP daemon is bad idea, local
ntpd acting as a  client should do it better and avoid excessive load on
remote NTP server so the collector is refactored to query local NTP
server.

2. Checking local clock against remote one does not check local ntpd
itself. Local ntpd may be down or out of sync due to network issues, but
clock will be OK.

3. Checking NTP server using sanity of it's response is tricky and
depends on ntpd implementation, that's why common `node_ntp_sanity`
variable is exported.

* `govendor add golang.org/x/net/ipv4`, it is dependency of github.com/beevik/ntp

* Update github.com/beevik/ntp to include boring SNTP fix

* Use variable name from RFC5905

* ntp: move code to make export of raw metrics more explicit

* Move NTP math to `github.com/beevik/ntp`

* Make `golint` happy

* Add some brief docs explaining `ntp` #655 and `timex` #664 modules

* ntp: drop XXX comment that got its decision

* ntp: add `_seconds` suffix to relevant metrics

* Better `node_ntp_leap` comment

* s/node_ntp_reftime/node_ntp_reference_timestamp_seconds/ as requested by @discordianfish

* Extract subsystem name to const as suggested by @SuperQ
2017-09-19 10:36:14 +02:00

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Go

// Copyright 2013 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
import "golang.org/x/net/internal/iana"
// An ICMPType represents a type of ICMP message.
type ICMPType int
func (typ ICMPType) String() string {
s, ok := icmpTypes[typ]
if !ok {
return "<nil>"
}
return s
}
// Protocol returns the ICMPv4 protocol number.
func (typ ICMPType) Protocol() int {
return iana.ProtocolICMP
}
// An ICMPFilter represents an ICMP message filter for incoming
// packets. The filter belongs to a packet delivery path on a host and
// it cannot interact with forwarding packets or tunnel-outer packets.
//
// Note: RFC 8200 defines a reasonable role model and it works not
// only for IPv6 but IPv4. A node means a device that implements IP.
// A router means a node that forwards IP packets not explicitly
// addressed to itself, and a host means a node that is not a router.
type ICMPFilter struct {
icmpFilter
}
// Accept accepts incoming ICMP packets including the type field value
// typ.
func (f *ICMPFilter) Accept(typ ICMPType) {
f.accept(typ)
}
// Block blocks incoming ICMP packets including the type field value
// typ.
func (f *ICMPFilter) Block(typ ICMPType) {
f.block(typ)
}
// SetAll sets the filter action to the filter.
func (f *ICMPFilter) SetAll(block bool) {
f.setAll(block)
}
// WillBlock reports whether the ICMP type will be blocked.
func (f *ICMPFilter) WillBlock(typ ICMPType) bool {
return f.willBlock(typ)
}