Pierre-Olivier Mercier
90f1b4943f
Generic SRV records checker for happyDomain.
For each SRV record attached to an svcs.UnknownSRV service, the checker
resolves every target and probes reachability:
- DNS resolution (A/AAAA), CNAME detection (RFC 2782 violation),
null-target detection (RFC 2782 "service explicitly unavailable")
- TCP connect to target:port for _tcp SRVs
- UDP probe for _udp SRVs, using ICMP port-unreachable detection
The checker also publishes TLS endpoints (host, port, SNI) for every
SRV target hitting a well-known direct-TLS port (443, 465, 636, 853,
993, 995, 5061, 5223, …) via the EndpointDiscoverer SDK interface, so
a downstream TLS checker can pick them up.
The HTML report groups records as cards and surfaces the most common
failure scenarios (DNS failure, CNAME target, TCP unreachable,
null-target) at the top with remediation guidance.
73 lines
2.6 KiB
Go
73 lines
2.6 KiB
Go
// This file is part of the happyDomain (R) project.
|
|
// Copyright (c) 2020-2026 happyDomain
|
|
// Authors: Pierre-Olivier Mercier, et al.
|
|
//
|
|
// This program is offered under a commercial and under the AGPL license.
|
|
// For commercial licensing, contact us at <contact@happydomain.org>.
|
|
//
|
|
// For AGPL licensing:
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Affero General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Affero General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Affero General Public License
|
|
// along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
// Package checker implements the generic SRV records checker for happyDomain.
|
|
//
|
|
// TLS/certificate testing is intentionally out of scope: it is handled by a
|
|
// dedicated TLS checker.
|
|
package checker
|
|
|
|
import (
|
|
sdk "git.happydns.org/checker-sdk-go/checker"
|
|
)
|
|
|
|
const ObservationKeySRV sdk.ObservationKey = "srv_records"
|
|
|
|
const (
|
|
protoTCP = "tcp"
|
|
protoUDP = "udp"
|
|
)
|
|
|
|
type SRVRecord struct {
|
|
Service string `json:"service"`
|
|
Proto string `json:"proto"`
|
|
Owner string `json:"owner"`
|
|
Target string `json:"target"`
|
|
Port uint16 `json:"port"`
|
|
Priority uint16 `json:"priority"`
|
|
Weight uint16 `json:"weight"`
|
|
|
|
IsNullTarget bool `json:"isNullTarget,omitempty"` // target == "." means "no service"
|
|
IsCNAME bool `json:"isCNAME,omitempty"` // RFC 2782: MUST NOT be CNAME
|
|
CNAMEChain []string `json:"cnameChain,omitempty"`
|
|
Addresses []string `json:"addresses,omitempty"`
|
|
ResolveError string `json:"resolveError,omitempty"`
|
|
|
|
Probes []ProbeResult `json:"probes,omitempty"`
|
|
}
|
|
|
|
type ProbeResult struct {
|
|
Address string `json:"address"`
|
|
Proto string `json:"proto"`
|
|
// Connected reports whether the probe should be treated as reachable.
|
|
// For TCP this is a true handshake. For UDP, where silent drops are
|
|
// indistinguishable from a working service, a timeout also sets
|
|
// Connected=true and populates Error with an explanatory note: the
|
|
// rule treats "no ICMP unreachable" as best-effort reachable.
|
|
Connected bool `json:"connected"`
|
|
LatencyMs float64 `json:"latencyMs,omitempty"`
|
|
Error string `json:"error,omitempty"`
|
|
}
|
|
|
|
type SRVData struct {
|
|
ServiceDomain string `json:"serviceDomain"`
|
|
Records []SRVRecord `json:"records"`
|
|
}
|