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.
85 lines
2.7 KiB
Go
85 lines
2.7 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/>.
|
|
|
|
//go:build standalone
|
|
|
|
package checker
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"net"
|
|
"strings"
|
|
|
|
sdk "git.happydns.org/checker-sdk-go/checker"
|
|
)
|
|
|
|
// collectFallback queries DNS for SRV records directly when no upstream
|
|
// service payload is available (standalone CLI/HTTP mode).
|
|
func (p *srvProvider) collectFallback(ctx context.Context, opts sdk.CheckerOptions) (any, error) {
|
|
subdomain, _ := sdk.GetOption[string](opts, "subdomain")
|
|
domain, _ := sdk.GetOption[string](opts, "domain")
|
|
|
|
serviceDomain := strings.TrimSuffix(subdomain, ".")
|
|
if domain != "" {
|
|
if serviceDomain != "" {
|
|
serviceDomain += "." + strings.TrimSuffix(domain, ".")
|
|
} else {
|
|
serviceDomain = strings.TrimSuffix(domain, ".")
|
|
}
|
|
}
|
|
if serviceDomain == "" {
|
|
return nil, fmt.Errorf("missing 'domain' option")
|
|
}
|
|
|
|
// Empty service/proto tells the resolver to query the literal name as-is,
|
|
// preserving _svc._proto labels already encoded in serviceDomain.
|
|
_, srvs, err := net.DefaultResolver.LookupSRV(ctx, "", "", serviceDomain)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("SRV lookup for %s: %w", serviceDomain, err)
|
|
}
|
|
if len(srvs) == 0 {
|
|
return nil, fmt.Errorf("no SRV records at %s", serviceDomain)
|
|
}
|
|
|
|
tcpTimeout := durationOpt(opts, "tcpTimeout", 3000)
|
|
udpTimeout := durationOpt(opts, "udpTimeout", 2000)
|
|
|
|
svc, proto := parseOwner(serviceDomain, serviceDomain)
|
|
data := &SRVData{
|
|
ServiceDomain: serviceDomain,
|
|
Records: make([]SRVRecord, 0, len(srvs)),
|
|
}
|
|
for _, s := range srvs {
|
|
rec := SRVRecord{
|
|
Service: svc,
|
|
Proto: proto,
|
|
Owner: serviceDomain,
|
|
Target: strings.TrimSuffix(s.Target, "."),
|
|
Port: s.Port,
|
|
Priority: s.Priority,
|
|
Weight: s.Weight,
|
|
}
|
|
resolveAndProbe(ctx, &rec, tcpTimeout, udpTimeout)
|
|
data.Records = append(data.Records, rec)
|
|
}
|
|
return data, nil
|
|
}
|