Pierre-Olivier Mercier
749ba428a7
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.
54 lines
1.8 KiB
Go
54 lines
1.8 KiB
Go
// Package checker implements the generic SRV records checker for happyDomain.
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//
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// For each SRV record attached to the target service it performs:
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//
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// - DNS resolution of every SRV target (A/AAAA, CNAME detection)
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// - TCP connectivity test on target:port (_tcp SRVs)
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// - UDP probe on target:port (_udp SRVs)
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//
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// TLS/certificate testing is intentionally out of scope: it is handled by a
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// dedicated TLS checker.
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//
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// Checks are performed natively using the Go standard library (no external
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// testsuite).
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package checker
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import (
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sdk "git.happydns.org/checker-sdk-go/checker"
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)
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const ObservationKeySRV sdk.ObservationKey = "srv_records"
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type SRVRecord struct {
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Service string `json:"service"`
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Proto string `json:"proto"`
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Owner string `json:"owner"`
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Target string `json:"target"`
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Port uint16 `json:"port"`
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Priority uint16 `json:"priority"`
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Weight uint16 `json:"weight"`
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// DNS resolution results
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IsNullTarget bool `json:"isNullTarget,omitempty"` // target == "." means "no service"
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IsCNAME bool `json:"isCNAME,omitempty"` // RFC 2782: MUST NOT be CNAME
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CNAMEChain []string `json:"cnameChain,omitempty"`
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Addresses []string `json:"addresses,omitempty"`
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ResolveError string `json:"resolveError,omitempty"`
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// Reachability checks per address
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Probes []ProbeResult `json:"probes,omitempty"`
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}
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type ProbeResult struct {
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Address string `json:"address"`
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Proto string `json:"proto"` // "tcp" or "udp"
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Connected bool `json:"connected"`
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LatencyMs float64 `json:"latencyMs,omitempty"`
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Error string `json:"error,omitempty"`
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}
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type SRVData struct {
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ServiceDomain string `json:"serviceDomain"` // e.g. _sip._tcp.example.com
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Records []SRVRecord `json:"records"`
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CollectError string `json:"collectError,omitempty"`
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}
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