checker-http/checker/service.go

80 lines
2.5 KiB
Go

// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
package checker
import (
"context"
"encoding/json"
"fmt"
"net"
sdk "git.happydns.org/checker-sdk-go/checker"
happydns "git.happydns.org/happyDomain/model"
"git.happydns.org/happyDomain/services/abstract"
)
// resolver is the *net.Resolver used to discover additional A/AAAA records
// beyond what abstract.Server pins. Overridable in tests.
var resolver = net.DefaultResolver
// resolveServer extracts the *abstract.Server payload from the options.
func resolveServer(opts sdk.CheckerOptions) (*abstract.Server, error) {
svc, ok := sdk.GetOption[happydns.ServiceMessage](opts, OptionService)
if !ok {
return nil, fmt.Errorf("no service in options: did the host wire AutoFillService?")
}
if svc.Type != "abstract.Server" {
return nil, fmt.Errorf("service is %q, expected abstract.Server", svc.Type)
}
var server abstract.Server
if err := json.Unmarshal(svc.Service, &server); err != nil {
return nil, fmt.Errorf("unmarshal abstract.Server: %w", err)
}
return &server, nil
}
// addressesFromServer returns the (host, ips) tuple to probe. origin is
// the service's parent zone; the A/AAAA Hdr.Name is relative to it as
// happyDomain encodes service owners, so we must join before using as FQDN.
func addressesFromServer(server *abstract.Server, origin string) (host string, ips []string) {
if server.A != nil && len(server.A.A) > 0 {
host = sdk.JoinRelative(server.A.Hdr.Name, origin)
ips = append(ips, server.A.A.String())
}
if server.AAAA != nil && len(server.AAAA.AAAA) > 0 {
if host == "" {
host = sdk.JoinRelative(server.AAAA.Hdr.Name, origin)
}
ips = append(ips, server.AAAA.AAAA.String())
}
return
}
// discoverIPs resolves host through the system resolver and returns every
// A/AAAA address it knows about. abstract.Server only carries one pinned A
// and one pinned AAAA, so a domain backed by multiple records would only
// be partially probed without this.
//
// Failures are non-fatal: callers fall back to the pinned IPs from
// addressesFromServer. Returned IPs are deduped against `seen`.
func discoverIPs(ctx context.Context, host string, seen map[string]struct{}) []string {
if host == "" {
return nil
}
addrs, err := resolver.LookupIP(ctx, "ip", host)
if err != nil {
return nil
}
var out []string
for _, ip := range addrs {
s := ip.String()
if _, dup := seen[s]; dup {
continue
}
seen[s] = struct{}{}
out = append(out, s)
}
return out
}