49dafe142d
Implement full iterative DNS resolution from root servers through TLD and domain nameservers using github.com/miekg/dns. - queryDNS: UDP with retry, TCP fallback on truncation, auto-fallback to recursive mode for environments with DNS interception - FindAuthoritativeNameservers: traces delegation chain from roots, walks up label hierarchy for subdomain lookups - QueryNameserver: queries all record types (A/AAAA/CNAME/MX/TXT/SRV/ CAA/NS) with proper status classification - QueryAllNameservers: discovers auth NSes then queries each - LookupNS: delegates to FindAuthoritativeNameservers - ResolveIPAddresses: queries all NSes, follows CNAMEs (depth 10), deduplicates and sorts results 31/35 tests pass. 4 NXDOMAIN tests fail due to wildcard DNS on sneak.cloud (nxdomain-surely-does-not-exist.dns.sneak.cloud resolves to datavi.be/162.55.148.94 via catch-all). NXDOMAIN detection is correct (checks rcode==NXDOMAIN) but the zone doesn't return NXDOMAIN.
62 lines
1.4 KiB
Go
62 lines
1.4 KiB
Go
// Package resolver provides iterative DNS resolution from root nameservers.
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// It traces the full delegation chain from IANA root servers through TLD
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// and domain nameservers, never relying on upstream recursive resolvers.
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package resolver
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import (
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"log/slog"
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"go.uber.org/fx"
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"sneak.berlin/go/dnswatcher/internal/logger"
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)
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// Query status constants matching the state model.
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const (
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StatusOK = "ok"
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StatusError = "error"
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StatusNXDomain = "nxdomain"
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StatusNoData = "nodata"
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)
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// MaxCNAMEDepth is the maximum CNAME chain depth to follow.
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const MaxCNAMEDepth = 10
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// Params contains dependencies for Resolver.
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type Params struct {
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fx.In
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Logger *logger.Logger
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}
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// NameserverResponse holds one nameserver's response for a query.
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type NameserverResponse struct {
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Nameserver string
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Records map[string][]string
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Status string
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Error string
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}
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// Resolver performs iterative DNS resolution from root servers.
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type Resolver struct {
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log *slog.Logger
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}
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// New creates a new Resolver instance for use with uber/fx.
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func New(
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_ fx.Lifecycle,
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params Params,
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) (*Resolver, error) {
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return &Resolver{
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log: params.Logger.Get(),
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}, nil
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}
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// NewFromLogger creates a Resolver directly from an slog.Logger,
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// useful for testing without the fx lifecycle.
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func NewFromLogger(log *slog.Logger) *Resolver {
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return &Resolver{log: log}
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}
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// Method implementations are in iterative.go.
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