Pierre-Olivier Mercier
7e50f404a1
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.
46 lines
1.4 KiB
Go
46 lines
1.4 KiB
Go
package checker
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"strings"
|
|
|
|
sdk "git.happydns.org/checker-sdk-go/checker"
|
|
)
|
|
|
|
// Port 0 is valid on the wire but no client can connect to it; null targets are exempt since their port is irrelevant.
|
|
|
|
type rulePortValid struct{}
|
|
|
|
func RulePortValid() sdk.CheckRule { return &rulePortValid{} }
|
|
func (rulePortValid) Name() string { return "srv_port_valid" }
|
|
func (rulePortValid) Description() string {
|
|
return "SRV records advertise a non-zero port that clients can actually connect to."
|
|
}
|
|
func (rulePortValid) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
|
|
d, cs := getData(ctx, obs)
|
|
if cs != nil {
|
|
return []sdk.CheckState{*cs}
|
|
}
|
|
var bad []string
|
|
var checked int
|
|
for _, r := range d.Records {
|
|
if r.IsNullTarget {
|
|
continue
|
|
}
|
|
checked++
|
|
if r.Port == 0 {
|
|
bad = append(bad, fmt.Sprintf("%s (port %d)", r.Owner, r.Port))
|
|
}
|
|
}
|
|
if checked == 0 {
|
|
return []sdk.CheckState{{Status: sdk.StatusInfo, Code: "srv_port_na",
|
|
Message: "No active SRV targets to check ports on."}}
|
|
}
|
|
if len(bad) == 0 {
|
|
return []sdk.CheckState{{Status: sdk.StatusOK, Code: "srv_port_ok",
|
|
Message: fmt.Sprintf("All %d SRV record(s) advertise a non-zero port.", checked)}}
|
|
}
|
|
return []sdk.CheckState{{Status: sdk.StatusCrit, Code: "srv_port_zero",
|
|
Message: fmt.Sprintf("SRV record(s) advertise port 0: %s", strings.Join(bad, ", "))}}
|
|
}
|