├── .gitignore ├── .dockerignore ├── go.mod ├── Dockerfile ├── .github └── workflows │ ├── go.yml │ └── lint.yml ├── .cspell.json ├── Makefile ├── zone ├── root.go ├── parse.go └── zone.go ├── psl └── psl.go ├── release.mk ├── README.md ├── resolver ├── cache_test.go ├── cache.go ├── context_test.go ├── resolver_test.go └── resolver.go ├── save └── savezone.go ├── main.go ├── go.sum ├── status └── status.go ├── axfr.go └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | allxfr 2 | zones/ 3 | -------------------------------------------------------------------------------- /.dockerignore: -------------------------------------------------------------------------------- 1 | allxfr 2 | Dockerfile 3 | .git* 4 | unbound/ 5 | -------------------------------------------------------------------------------- /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/lanrat/allxfr 2 | 3 | go 1.23.0 4 | 5 | require ( 6 | github.com/miekg/dns v1.1.67 7 | github.com/weppos/publicsuffix-go v0.40.2 8 | golang.org/x/sync v0.16.0 9 | ) 10 | 11 | require ( 12 | golang.org/x/mod v0.26.0 // indirect 13 | golang.org/x/net v0.42.0 // indirect 14 | golang.org/x/sys v0.34.0 // indirect 15 | golang.org/x/text v0.27.0 // indirect 16 | golang.org/x/tools v0.35.0 // indirect 17 | ) 18 | -------------------------------------------------------------------------------- /Dockerfile: -------------------------------------------------------------------------------- 1 | # build stage 2 | FROM golang:alpine AS build-env 3 | RUN apk update && apk add --no-cache make git 4 | 5 | # Accept VERSION as a build argument 6 | ARG VERSION 7 | ENV VERSION=${VERSION} 8 | 9 | WORKDIR /go/app/ 10 | COPY go.mod go.sum ./ 11 | RUN go mod download 12 | 13 | COPY . . 14 | RUN make 15 | 16 | # final stage 17 | FROM alpine 18 | 19 | COPY --from=build-env /go/app/allxfr /bin/allxfr 20 | 21 | USER 1000 22 | 23 | ENTRYPOINT ["allxfr"] 24 | -------------------------------------------------------------------------------- /.github/workflows/go.yml: -------------------------------------------------------------------------------- 1 | name: Go 2 | 3 | on: 4 | push: 5 | branches: [ main ] 6 | pull_request: 7 | branches: [ main ] 8 | 9 | jobs: 10 | 11 | build: 12 | name: Build and Test 13 | runs-on: ubuntu-latest 14 | steps: 15 | - uses: actions/checkout@v4 16 | 17 | - uses: actions/setup-go@v5 18 | with: 19 | go-version-file: go.mod 20 | 21 | - name: Get dependencies 22 | run: make deps 23 | 24 | - name: Run tests 25 | run: make test 26 | 27 | - name: Build 28 | run: make 29 | -------------------------------------------------------------------------------- /.github/workflows/lint.yml: -------------------------------------------------------------------------------- 1 | name: Lint 2 | 3 | on: 4 | push: 5 | branches: [ main ] 6 | pull_request: 7 | branches: [ main ] 8 | 9 | permissions: 10 | contents: read 11 | pull-requests: read 12 | 13 | jobs: 14 | golangci: 15 | name: lint 16 | runs-on: ubuntu-latest 17 | steps: 18 | - uses: actions/checkout@v4 19 | 20 | - uses: actions/setup-go@v5 21 | with: 22 | go-version-file: go.mod 23 | 24 | - name: golangci-lint 25 | uses: golangci/golangci-lint-action@v8 26 | with: 27 | version: latest -------------------------------------------------------------------------------- /.cspell.json: -------------------------------------------------------------------------------- 1 | { 2 | "version": "0.2", 3 | "ignorePaths": [], 4 | "dictionaryDefinitions": [], 5 | "dictionaries": [], 6 | "words": [ 7 | "AAAAIPs", 8 | "allxfr", 9 | "AXFR", 10 | "errgroup", 11 | "gofmt", 12 | "golangci", 13 | "GOPROXY", 14 | "hostnames", 15 | "installsuffix", 16 | "ixfr", 17 | "lanrat", 18 | "miekg", 19 | "Minttl", 20 | "NOERROR", 21 | "NXDOMAIN", 22 | "publicsuffix", 23 | "qtype", 24 | "Rcode", 25 | "Rrtype", 26 | "staticcheck", 27 | "trimpath", 28 | "weppos", 29 | "zonefile" 30 | ], 31 | "ignoreWords": [], 32 | "import": [] 33 | } 34 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | default: allxfr 2 | 3 | include release.mk 4 | 5 | # creates static binaries 6 | CC := CGO_ENABLED=0 go build -ldflags "-w -s -X main.version=${VERSION}" -trimpath -a -installsuffix cgo 7 | 8 | SOURCES := $(shell find . -type f -name '*.go') 9 | BIN := allxfr 10 | 11 | .PHONY: all fmt docker clean deps update-deps 12 | 13 | docker: Dockerfile $(SOURCES) go.mod go.sum 14 | docker build --build-arg VERSION=${VERSION} -t="lanrat/allxfr" . 15 | 16 | $(BIN): $(SOURCES) go.mod go.sum 17 | $(CC) -o $@ 18 | 19 | check: 20 | golangci-lint run 21 | staticcheck -checks all ./... 22 | 23 | update-deps: go.mod 24 | GOPROXY=direct go get -u ./... 25 | go mod tidy 26 | 27 | deps: go.mod 28 | go mod download 29 | 30 | test: 31 | go test -timeout 15s -v ./... 32 | 33 | clean: 34 | rm $(BIN) 35 | 36 | fmt: 37 | go fmt . 38 | 39 | -------------------------------------------------------------------------------- /zone/root.go: -------------------------------------------------------------------------------- 1 | package zone 2 | 3 | import ( 4 | "fmt" 5 | 6 | "github.com/miekg/dns" 7 | ) 8 | 9 | // RootAXFR performs a zone transfer against a root nameserver to obtain the root zone. 10 | // It connects to the specified nameserver on port 53 and requests the root zone ("."). 11 | // Returns a Zone containing all the NS, A, and AAAA records from the root zone. 12 | func RootAXFR(ns string) (Zone, error) { 13 | m := new(dns.Msg) 14 | m.SetQuestion(".", dns.TypeAXFR) 15 | t := new(dns.Transfer) 16 | 17 | var root Zone 18 | env, err := t.In(m, fmt.Sprintf("%s:53", ns)) 19 | if err != nil { 20 | return root, fmt.Errorf("transfer error from %v: %w", ns, err) 21 | } 22 | for e := range env { 23 | if e.Error != nil { 24 | return root, fmt.Errorf("transfer envelope error from %v: %w", ns, e.Error) 25 | } 26 | for _, r := range e.RR { 27 | root.AddRecord(r) 28 | } 29 | } 30 | return root, nil 31 | } 32 | -------------------------------------------------------------------------------- /zone/parse.go: -------------------------------------------------------------------------------- 1 | // Package zone provides functionality for parsing and managing DNS zone files. 2 | package zone 3 | 4 | import ( 5 | "compress/gzip" 6 | "io" 7 | "os" 8 | "strings" 9 | 10 | "github.com/miekg/dns" 11 | ) 12 | 13 | // ParseZoneFile parses a DNS zone file and returns a Zone containing the records. 14 | // It supports both plain text and gzip-compressed zone files (detected by .gz extension). 15 | // The function extracts NS, A, and AAAA records to build the zone structure. 16 | func ParseZoneFile(filename string) (Zone, error) { 17 | var z Zone 18 | var fileReader io.Reader 19 | file, err := os.Open(filename) 20 | fileReader = file 21 | if err != nil { 22 | return z, err 23 | } 24 | defer func() { _ = file.Close() }() 25 | if strings.HasSuffix(filename, ".gz") { 26 | gz, err := gzip.NewReader(file) 27 | if err != nil { 28 | return z, err 29 | } 30 | fileReader = gz 31 | defer func() { _ = gz.Close() }() 32 | } 33 | zp := dns.NewZoneParser(fileReader, "", "") 34 | for rr, ok := zp.Next(); ok; rr, ok = zp.Next() { 35 | z.AddRecord(rr) 36 | } 37 | 38 | if err := zp.Err(); err != nil { 39 | return z, err 40 | } 41 | return z, nil 42 | } 43 | -------------------------------------------------------------------------------- /psl/psl.go: -------------------------------------------------------------------------------- 1 | // Package psl provides functionality to fetch domains from the Public Suffix List. 2 | package psl 3 | 4 | import ( 5 | "context" 6 | "net/http" 7 | "time" 8 | 9 | "github.com/miekg/dns" 10 | "github.com/weppos/publicsuffix-go/publicsuffix" 11 | ) 12 | 13 | const ( 14 | pslURL = "https://publicsuffix.org/list/public_suffix_list.dat" 15 | pslTimeout = 30 * time.Second 16 | ) 17 | 18 | // GetDomains fetches and parses the Public Suffix List to extract domain names. 19 | // It downloads the PSL from publicsuffix.org, parses the rules (excluding private domains), 20 | // converts IDN domains to ASCII, and returns them as fully qualified domain names. 21 | // The function includes timeout handling to prevent indefinite blocking. 22 | func GetDomains() ([]string, error) { 23 | ctx, cancel := context.WithTimeout(context.Background(), pslTimeout) 24 | defer cancel() 25 | 26 | req, err := http.NewRequestWithContext(ctx, "GET", pslURL, nil) 27 | if err != nil { 28 | return nil, err 29 | } 30 | 31 | client := &http.Client{Timeout: pslTimeout} 32 | resp, err := client.Do(req) 33 | if err != nil { 34 | return nil, err 35 | } 36 | defer func() { _ = resp.Body.Close() }() 37 | 38 | list := publicsuffix.NewList() 39 | options := &publicsuffix.ParserOption{ 40 | PrivateDomains: false, 41 | } 42 | rules, err := list.Load(resp.Body, options) 43 | if err != nil { 44 | return nil, err 45 | } 46 | 47 | out := make([]string, 0, len(rules)) 48 | for _, rule := range rules { 49 | if rule.Type != publicsuffix.ExceptionType { 50 | domain, err := publicsuffix.ToASCII(rule.Value) 51 | if err != nil { 52 | return out, err 53 | } 54 | out = append(out, dns.Fqdn(domain)) 55 | } 56 | } 57 | return out, nil 58 | } 59 | -------------------------------------------------------------------------------- /release.mk: -------------------------------------------------------------------------------- 1 | # Get the current version from git. 2 | # `git describe` will use the most recent tag. 3 | # `--tags` ensures any tag is considered, not just annotated ones. 4 | # `--always` ensures that if no tags are present, the commit hash is used. 5 | # `--dirty` will append "-dirty" if the working directory has uncommitted changes. 6 | VERSION ?= $(shell git describe --tags --always --dirty) 7 | 8 | # Release target to create a new semantic version tag 9 | .PHONY: release-tag 10 | release-tag: check 11 | # This shell 'if' statement runs at execution time, not parse time. 12 | @if [ -z "$(BUMP)" ]; then \ 13 | echo "Error: BUMP is not set. Usage: make release BUMP=patch|minor|major"; \ 14 | exit 1; \ 15 | fi 16 | 17 | # 1. Check for a clean working directory 18 | @if ! git diff --quiet; then \ 19 | echo "Error: Working directory is not clean. Commit or stash changes before releasing."; \ 20 | exit 1; \ 21 | fi 22 | 23 | # 2. Get the latest git tag, or start at v0.0.0 24 | @CURRENT_TAG=$$(git describe --tags --abbrev=0 2>/dev/null || echo "v0.0.0"); \ 25 | CURRENT_VERSION=$$(echo $$CURRENT_TAG | sed 's/^v//'); \ 26 | MAJOR=$$(echo $$CURRENT_VERSION | cut -d. -f1); \ 27 | MINOR=$$(echo $$CURRENT_VERSION | cut -d. -f2); \ 28 | PATCH=$$(echo $$CURRENT_VERSION | cut -d. -f3); \ 29 | \ 30 | if [ "$(BUMP)" = "patch" ]; then \ 31 | PATCH=$$((PATCH + 1)); \ 32 | elif [ "$(BUMP)" = "minor" ]; then \ 33 | MINOR=$$((MINOR + 1)); \ 34 | PATCH=0; \ 35 | elif [ "$(BUMP)" = "major" ]; then \ 36 | MAJOR=$$((MAJOR + 1)); \ 37 | MINOR=0; \ 38 | PATCH=0; \ 39 | else \ 40 | echo "Error: Invalid BUMP value. Use 'patch', 'minor', or 'major'."; \ 41 | exit 1; \ 42 | fi; \ 43 | \ 44 | NEW_TAG="v$${MAJOR}.$${MINOR}.$${PATCH}"; \ 45 | echo "Current version: $$CURRENT_TAG"; \ 46 | echo "Creating new version: $$NEW_TAG"; \ 47 | git tag $$NEW_TAG; \ 48 | git push origin $$NEW_TAG; -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # ALLXFR 2 | 3 | ## AXFR all the things! 4 | 5 | 6 | 7 | This tool performs a [zone transfer (AXFR)](https://en.wikipedia.org/wiki/DNS_zone_transfer) against the root zone servers to obtain the [root zone file](https://www.iana.org/domains/root/files). And then attempts opportunistic zone transfers for every IP for every nameserver for a given zone. Additionally, each NS/A/AAAA record is also re-queried to find additional servers or IPs not included as root glue. 8 | 9 | Most zones do not allow zone transfers, however a few do. Sometimes only on a single IP for a given nameserver and not the others, and sometimes only for servers or IPs that are authoritative but not included in the root zones. This tool will try them all and save every successful transfer. 10 | 11 | This tool works best on an IPv4/IPv6 dual stack internet connection. 12 | 13 | Providing a zone file with the `-zonefile` flag will attempt a transfer with the domains and sub-domains in the zone file provided. 14 | 15 | TLDs in the [Public Suffix List](https://publicsuffix.org/) can be attempted as well with the `-psl` flag. 16 | 17 | ## Example 18 | 19 | ```console 20 | ./allxfr -dry-run 21 | ROOT g.root-servers.net. xfr size: 22017 records in 1.334s 22 | mr. ns-mr.nic.tn. (41.228.63.70) xfr size: 444 records in 337ms 23 | sl. ns1.neoip.com. (45.83.41.38) xfr size: 455 records in 592ms 24 | sy. ns1.tld.sy. (82.137.200.85) xfr size: 1594 records in 870ms 25 | cd. ns-root-2.scpt-network.com. (41.79.235.67) xfr size: 497 records in 598ms 26 | my. a.nic.my. (103.44.108.53) xfr size: 1592 records in 608ms 27 | mq. ns1-mq.mediaserv.net. (213.16.20.3) xfr size: 1541 records in 299ms 28 | td. nsa.nic.td. (154.68.159.246) xfr size: 492 records in 1.821s 29 | gp. ns2.nic.gp. (193.218.114.34) xfr size: 1578 records in 195ms 30 | xn--54b7fta0cc. bayanno.btcl.net.bd. (180.211.212.213) xfr size: 915 records in 728ms 31 | xn--ogbpf8fl. ns1.tld.sy. (82.137.200.85) xfr size: 271 records in 460ms 32 | xn--90ae. a.nic.bg. (2a02:6a80::192:92:129:99) xfr size: 305 records in 326ms 33 | cv. cv01.dns.pt. (185.39.208.18) xfr size: 507 records in 333ms 34 | bd. surma.btcl.net.bd. (203.112.194.232) xfr size: 52 records in 486ms 35 | rw. ns1.ricta.org.rw. (196.49.7.188) xfr size: 1515 records in 1.269s 36 | gf. ns1-mq.mediaserv.net. (213.16.20.3) xfr size: 1531 records in 304ms 37 | bn. ns2.bnnic.bn. (202.93.214.163) xfr size: 79 records in 395ms 38 | tj. ns2.tojikiston.com. (193.111.11.4) xfr size: 1690 records in 998ms 39 | pg. ns1.tiare.net.pg. (202.165.192.23) xfr size: 447 records in 409ms 40 | mw. domwe.sdn.mw. (41.87.5.162) xfr size: 1538 records in 938ms 41 | xn--j1amh. tier1.num.net.ua. (193.110.163.134) xfr size: 1055 records in 1.349s 42 | sv. cir.red.sv. (168.243.254.1) xfr size: 1514 records in 883ms 43 | 21 / 1516 transfered in 3m29.92 44 | ``` 45 | 46 | ## Usage 47 | 48 | ```console 49 | Usage of ./allxfr: 50 | -dry-run 51 | only test if xfr is allowed by retrieving one envelope 52 | -ixfr 53 | attempt an IXFR instead of AXFR 54 | -out string 55 | directory to save found zones in (default "zones") 56 | -overwrite 57 | if zone already exists on disk, overwrite it with newer data 58 | -parallel uint 59 | number of parallel zone transfers to perform (default 10) 60 | -psl 61 | attempt AXFR from zones listed in the public suffix list 62 | -retry int 63 | number of times to retry failed operations (default 3) 64 | -save-all 65 | attempt AXFR from every nameserver for a given zone and save all answers 66 | -status-listen string 67 | enable HTTP status server on specified [IP:]port (e.g., '8080', '127.0.0.1:8080', '[::1]:8080') 68 | -verbose 69 | enable verbose output 70 | -version 71 | print version and exit 72 | -zonefile string 73 | use the provided zonefile instead of getting the root zonefile 74 | ``` 75 | 76 | ## Building 77 | 78 | ```console 79 | go build 80 | ``` 81 | -------------------------------------------------------------------------------- /zone/zone.go: -------------------------------------------------------------------------------- 1 | package zone 2 | 3 | import ( 4 | "fmt" 5 | "net" 6 | "strings" 7 | 8 | "github.com/miekg/dns" 9 | ) 10 | 11 | // Zone contains the nameservers and nameserver IPs in a zone. 12 | // It maintains mappings between domain names and their nameservers, 13 | // as well as nameserver hostnames to their IP addresses. 14 | type Zone struct { 15 | // NS maps domain names to their authoritative nameservers 16 | NS map[string][]string 17 | // IP maps nameserver hostnames to their IPv4 and IPv6 addresses 18 | IP map[string][]net.IP 19 | // Records tracks the total number of records added to the zone 20 | Records int64 21 | } 22 | 23 | // AddRecord adds NS, A, and AAAA records to the zone. 24 | // It extracts nameserver and IP information from DNS resource records 25 | // and updates the zone's internal mappings accordingly. 26 | func (z *Zone) AddRecord(r dns.RR) { 27 | switch t := r.(type) { 28 | case *dns.A: 29 | z.AddIP(t.Hdr.Name, t.A) 30 | case *dns.AAAA: 31 | z.AddIP(t.Hdr.Name, t.AAAA) 32 | case *dns.NS: 33 | z.AddNS(t.Hdr.Name, t.Ns) 34 | } 35 | } 36 | 37 | // GetNameChan returns a channel that yields all domain names in the zone. 38 | // It skips the root zone (".") and .arpa domains as they are not suitable 39 | // for zone transfer attempts. The channel is closed when all domains are sent. 40 | func (z *Zone) GetNameChan() chan string { 41 | out := make(chan string) 42 | go func() { 43 | for domain := range z.NS { 44 | // skip root & arpa 45 | if domain == "." { 46 | continue 47 | } 48 | if domain == "arpa." || strings.HasSuffix(domain, ".arpa.") { 49 | continue 50 | } 51 | out <- domain 52 | } 53 | close(out) 54 | }() 55 | return out 56 | } 57 | 58 | // CountNS returns the number of unique domain names that have nameservers in the zone. 59 | func (z *Zone) CountNS() int { 60 | return len(z.NS) 61 | } 62 | 63 | // AddNS adds a nameserver for a domain to the zone. 64 | // Domain names are normalized to lowercase. If nameserver is empty, 65 | // only the domain entry is created without adding a nameserver. 66 | func (z *Zone) AddNS(domain, nameserver string) { 67 | domain = strings.ToLower(domain) 68 | if z.NS == nil { 69 | z.NS = make(map[string][]string) 70 | } 71 | _, ok := z.NS[domain] 72 | if !ok { 73 | z.NS[domain] = make([]string, 0, 4) 74 | } 75 | if len(nameserver) > 0 { 76 | nameserver = strings.ToLower(nameserver) 77 | z.NS[domain] = append(z.NS[domain], nameserver) 78 | z.Records++ 79 | } 80 | } 81 | 82 | // AddIP adds an IP address for a nameserver to the zone. 83 | // Nameserver names are normalized to lowercase. Both IPv4 and IPv6 84 | // addresses are supported and stored in the same slice. 85 | func (z *Zone) AddIP(nameserver string, ip net.IP) { 86 | nameserver = strings.ToLower(nameserver) 87 | if z.IP == nil { 88 | z.IP = make(map[string][]net.IP) 89 | } 90 | _, ok := z.IP[nameserver] 91 | if !ok { 92 | z.IP[nameserver] = make([]net.IP, 0, 4) 93 | } 94 | z.IP[nameserver] = append(z.IP[nameserver], ip) 95 | z.Records++ 96 | } 97 | 98 | // Print outputs the zone structure to stdout in a simple format. 99 | // It displays all domains with their nameservers, followed by 100 | // all nameservers with their IP addresses. 101 | func (z *Zone) Print() { 102 | fmt.Println("NS:") 103 | for zone := range z.NS { 104 | fmt.Printf("%s\n", zone) 105 | for i := range z.NS[zone] { 106 | fmt.Printf("\t%s\n", z.NS[zone][i]) 107 | } 108 | } 109 | fmt.Println("IP:") 110 | for ns := range z.IP { 111 | fmt.Printf("%s\n", ns) 112 | for i := range z.IP[ns] { 113 | fmt.Printf("\t%s\n", z.IP[ns][i]) 114 | } 115 | } 116 | } 117 | 118 | // PrintTree outputs the zone structure to stdout in a hierarchical tree format. 119 | // It shows domains, their nameservers, and the IP addresses for each nameserver 120 | // in an indented tree structure for better readability. 121 | func (z *Zone) PrintTree() { 122 | fmt.Println("Zones:") 123 | for zone := range z.NS { 124 | fmt.Printf("%s\n", zone) 125 | for i := range z.NS[zone] { 126 | fmt.Printf("\t%s\n", z.NS[zone][i]) 127 | for j := range z.IP[z.NS[zone][i]] { 128 | fmt.Printf("\t\t%s\n", z.IP[z.NS[zone][i]][j]) 129 | } 130 | } 131 | } 132 | } 133 | -------------------------------------------------------------------------------- /resolver/cache_test.go: -------------------------------------------------------------------------------- 1 | package resolver 2 | 3 | import ( 4 | "context" 5 | "net" 6 | "testing" 7 | "time" 8 | 9 | "github.com/miekg/dns" 10 | ) 11 | 12 | func TestCacheBasicFunctionality(t *testing.T) { 13 | resolver := NewWithCacheSize(10, defaultQueryTimeout) 14 | domain := "google.com" 15 | 16 | ctx := context.Background() 17 | 18 | result1, err := resolver.Resolve(ctx, domain, dns.TypeA) 19 | if err != nil { 20 | t.Fatalf("Failed to resolve %s: %v", domain, err) 21 | } 22 | 23 | start := time.Now() 24 | result2, err := resolver.Resolve(ctx, domain, dns.TypeA) 25 | duration := time.Since(start) 26 | 27 | if err != nil { 28 | t.Fatalf("Failed to resolve cached %s: %v", domain, err) 29 | } 30 | 31 | if duration > 100*time.Millisecond { 32 | t.Errorf("Cached lookup took too long: %v", duration) 33 | } 34 | 35 | if len(result1.Answer) != len(result2.Answer) { 36 | t.Errorf("Cache returned different number of answers") 37 | } 38 | } 39 | 40 | func TestCacheTTLExpiry(t *testing.T) { 41 | cache := newDNSCache(10) 42 | 43 | result := &Result{ 44 | Answer: []dns.RR{ 45 | &dns.A{ 46 | Hdr: dns.RR_Header{ 47 | Name: "test.com.", 48 | Rrtype: dns.TypeA, 49 | Class: dns.ClassINET, 50 | Ttl: 1, 51 | }, 52 | A: net.ParseIP("1.2.3.4"), 53 | }, 54 | }, 55 | } 56 | 57 | cache.put("test.com.:1", result, 1*time.Second) 58 | 59 | if cached, found := cache.get("test.com.:1"); !found { 60 | t.Error("Should find cached entry immediately") 61 | } else if len(cached.Answer) != 1 { 62 | t.Error("Cached result should have 1 answer") 63 | } 64 | 65 | time.Sleep(1100 * time.Millisecond) 66 | 67 | if _, found := cache.get("test.com.:1"); found { 68 | t.Error("Should not find expired cached entry") 69 | } 70 | } 71 | 72 | func TestCacheLRUEviction(t *testing.T) { 73 | cache := newDNSCache(2) 74 | 75 | result1 := &Result{Answer: []dns.RR{}} 76 | result2 := &Result{Answer: []dns.RR{}} 77 | result3 := &Result{Answer: []dns.RR{}} 78 | 79 | cache.put("key1", result1, 1*time.Hour) 80 | cache.put("key2", result2, 1*time.Hour) 81 | cache.put("key3", result3, 1*time.Hour) 82 | 83 | if _, found := cache.get("key1"); found { 84 | t.Error("key1 should have been evicted") 85 | } 86 | 87 | if _, found := cache.get("key2"); !found { 88 | t.Error("key2 should still be in cache") 89 | } 90 | 91 | if _, found := cache.get("key3"); !found { 92 | t.Error("key3 should still be in cache") 93 | } 94 | } 95 | 96 | func TestCacheLRUOrdering(t *testing.T) { 97 | cache := newDNSCache(3) 98 | 99 | result1 := &Result{Answer: []dns.RR{}} 100 | result2 := &Result{Answer: []dns.RR{}} 101 | result3 := &Result{Answer: []dns.RR{}} 102 | result4 := &Result{Answer: []dns.RR{}} 103 | 104 | cache.put("key1", result1, 1*time.Hour) 105 | cache.put("key2", result2, 1*time.Hour) 106 | cache.put("key3", result3, 1*time.Hour) 107 | 108 | cache.get("key1") 109 | 110 | cache.put("key4", result4, 1*time.Hour) 111 | 112 | if _, found := cache.get("key2"); found { 113 | t.Error("key2 should have been evicted (was least recently used)") 114 | } 115 | 116 | if _, found := cache.get("key1"); !found { 117 | t.Error("key1 should still be in cache (was accessed recently)") 118 | } 119 | } 120 | 121 | func TestCacheKeyGeneration(t *testing.T) { 122 | resolver := New() 123 | 124 | key1 := resolver.makeCacheKey("example.com.", dns.TypeA) 125 | key2 := resolver.makeCacheKey("example.com.", dns.TypeAAAA) 126 | key3 := resolver.makeCacheKey("test.com.", dns.TypeA) 127 | 128 | if key1 == key2 { 129 | t.Error("Different record types should generate different keys") 130 | } 131 | 132 | if key1 == key3 { 133 | t.Error("Different domains should generate different keys") 134 | } 135 | 136 | expected1 := "example.com.:1" 137 | if key1 != expected1 { 138 | t.Errorf("Expected key %s, got %s", expected1, key1) 139 | } 140 | } 141 | 142 | func TestCalculateTTL(t *testing.T) { 143 | resolver := New() 144 | 145 | result := &Result{ 146 | Answer: []dns.RR{ 147 | &dns.A{ 148 | Hdr: dns.RR_Header{Ttl: 300}, 149 | }, 150 | &dns.A{ 151 | Hdr: dns.RR_Header{Ttl: 600}, 152 | }, 153 | }, 154 | Authority: []dns.RR{ 155 | &dns.NS{ 156 | Hdr: dns.RR_Header{Ttl: 200}, 157 | }, 158 | }, 159 | } 160 | 161 | ttl := resolver.calculateTTL(result) 162 | expected := 200 * time.Second 163 | 164 | if ttl != expected { 165 | t.Errorf("Expected TTL %v, got %v", expected, ttl) 166 | } 167 | 168 | result.Authority[0].Header().Ttl = 30 169 | ttl = resolver.calculateTTL(result) 170 | expected = 60 * time.Second 171 | 172 | if ttl != expected { 173 | t.Errorf("Expected minimum TTL %v, got %v", expected, ttl) 174 | } 175 | } 176 | -------------------------------------------------------------------------------- /resolver/cache.go: -------------------------------------------------------------------------------- 1 | package resolver 2 | 3 | import ( 4 | "sync" 5 | "time" 6 | ) 7 | 8 | const ( 9 | defaultCacheSize = 1000 10 | ) 11 | 12 | // cacheEntry represents a single cached DNS result with metadata. 13 | type cacheEntry struct { 14 | result *Result // The cached DNS query result 15 | expiry time.Time // When this cache entry expires 16 | lastUsed time.Time // When this entry was last accessed (for LRU) 17 | negative bool // true for NXDOMAIN/negative cache entries 18 | } 19 | 20 | // cacheNode is a node in the doubly-linked list used for LRU cache implementation. 21 | type cacheNode struct { 22 | key string // Cache key for this entry 23 | entry *cacheEntry // The cached data 24 | prev *cacheNode // Previous node in the linked list 25 | next *cacheNode // Next node in the linked list 26 | } 27 | 28 | // dnsCache implements an LRU cache for DNS query results. 29 | // It uses a combination of a hash map for O(1) lookups and a doubly-linked 30 | // list for O(1) LRU operations. 31 | type dnsCache struct { 32 | mutex sync.RWMutex // Protects all cache operations 33 | capacity int // Maximum number of entries to store 34 | cache map[string]*cacheNode // Hash map for fast lookups 35 | head *cacheNode // Head of doubly-linked list (most recent) 36 | tail *cacheNode // Tail of doubly-linked list (least recent) 37 | } 38 | 39 | // newDNSCache creates a new DNS cache with the specified capacity. 40 | // If capacity is <= 0, it defaults to defaultCacheSize. 41 | func newDNSCache(capacity int) *dnsCache { 42 | if capacity <= 0 { 43 | capacity = defaultCacheSize 44 | } 45 | 46 | head := &cacheNode{} 47 | tail := &cacheNode{} 48 | head.next = tail 49 | tail.prev = head 50 | 51 | return &dnsCache{ 52 | capacity: capacity, 53 | cache: make(map[string]*cacheNode), 54 | head: head, 55 | tail: tail, 56 | } 57 | } 58 | 59 | // get retrieves a cached DNS result by key. 60 | // It checks for expiration and updates the LRU order on cache hits. 61 | // Returns (result, found) where found indicates if the key was in cache and not expired. 62 | func (c *dnsCache) get(key string) (*Result, bool) { 63 | c.mutex.Lock() 64 | defer c.mutex.Unlock() 65 | 66 | node, exists := c.cache[key] 67 | if !exists { 68 | return nil, false 69 | } 70 | 71 | if time.Now().After(node.entry.expiry) { 72 | c.removeNode(node) 73 | delete(c.cache, key) 74 | return nil, false 75 | } 76 | 77 | node.entry.lastUsed = time.Now() 78 | c.moveToHead(node) 79 | 80 | return node.entry.result, true 81 | } 82 | 83 | // put stores a DNS result in the cache with the specified TTL. 84 | // This is a convenience wrapper around putWithNegative for positive cache entries. 85 | func (c *dnsCache) put(key string, result *Result, ttl time.Duration) { 86 | c.putWithNegative(key, result, ttl, false) 87 | } 88 | 89 | // putNegative stores a negative DNS result (like NXDOMAIN) in the cache. 90 | // Negative entries are handled specially for cache management purposes. 91 | func (c *dnsCache) putNegative(key string, result *Result, ttl time.Duration) { 92 | c.putWithNegative(key, result, ttl, true) 93 | } 94 | 95 | // putWithNegative is the internal implementation for storing cache entries. 96 | // It handles both positive and negative cache entries, manages LRU ordering, 97 | // and evicts old entries when the cache reaches capacity. 98 | func (c *dnsCache) putWithNegative(key string, result *Result, ttl time.Duration, negative bool) { 99 | c.mutex.Lock() 100 | defer c.mutex.Unlock() 101 | 102 | now := time.Now() 103 | entry := &cacheEntry{ 104 | result: result, 105 | expiry: now.Add(ttl), 106 | lastUsed: now, 107 | negative: negative, 108 | } 109 | 110 | if node, exists := c.cache[key]; exists { 111 | node.entry = entry 112 | c.moveToHead(node) 113 | return 114 | } 115 | 116 | newNode := &cacheNode{ 117 | key: key, 118 | entry: entry, 119 | } 120 | 121 | c.cache[key] = newNode 122 | c.addToHead(newNode) 123 | 124 | if len(c.cache) > c.capacity { 125 | tail := c.removeTail() 126 | delete(c.cache, tail.key) 127 | } 128 | } 129 | 130 | // addToHead adds a node to the head of the doubly-linked list (most recent position). 131 | func (c *dnsCache) addToHead(node *cacheNode) { 132 | node.prev = c.head 133 | node.next = c.head.next 134 | c.head.next.prev = node 135 | c.head.next = node 136 | } 137 | 138 | // removeNode removes a node from the doubly-linked list. 139 | func (c *dnsCache) removeNode(node *cacheNode) { 140 | node.prev.next = node.next 141 | node.next.prev = node.prev 142 | } 143 | 144 | // moveToHead moves an existing node to the head of the list (marks as most recently used). 145 | func (c *dnsCache) moveToHead(node *cacheNode) { 146 | c.removeNode(node) 147 | c.addToHead(node) 148 | } 149 | 150 | // removeTail removes and returns the node at the tail of the list (least recently used). 151 | func (c *dnsCache) removeTail() *cacheNode { 152 | lastNode := c.tail.prev 153 | c.removeNode(lastNode) 154 | return lastNode 155 | } 156 | -------------------------------------------------------------------------------- /save/savezone.go: -------------------------------------------------------------------------------- 1 | // Package save provides functionality for writing DNS zone files to disk with compression. 2 | // It handles the creation, writing, and finalization of zone files, including 3 | // automatic gzip compression, metadata comments, and atomic file operations 4 | // to ensure data integrity during the zone transfer process. 5 | package save 6 | 7 | import ( 8 | "bufio" 9 | "compress/gzip" 10 | "errors" 11 | "fmt" 12 | "os" 13 | "time" 14 | 15 | "github.com/miekg/dns" 16 | ) 17 | 18 | // File represents a zone file being written to disk with compression. 19 | // It manages the lifecycle of creating, writing, and finalizing DNS zone files. 20 | type File struct { 21 | filename string // Final filename for the zone file 22 | filenameTmp string // Temporary filename during writing 23 | zone string // Zone name being written 24 | bufWriter *bufio.Writer // Buffered writer for performance 25 | gzWriter *gzip.Writer // Gzip compression writer 26 | fileWriter *os.File // Underlying file writer 27 | records int64 // Number of DNS records written 28 | closed bool // Whether the file has been finalized 29 | pendingWrites []string // Comments buffered until first record is added 30 | } 31 | 32 | // New creates a new zone file writer for the specified zone and filename. 33 | // The file is not created until the first record is written, allowing 34 | // comments to be buffered efficiently. 35 | func New(zone, filename string) *File { 36 | f := new(File) 37 | f.filename = filename 38 | f.filenameTmp = fmt.Sprintf("%s.tmp", f.filename) 39 | f.zone = zone 40 | return f 41 | } 42 | 43 | // Records returns the number of DNS records written to the zone file. 44 | func (f *File) Records() int64 { 45 | return f.records 46 | } 47 | 48 | // WriteComment adds a comment to the zone file 49 | func (f *File) WriteComment(comment string) error { 50 | if f.closed { 51 | return ErrFileClosed 52 | } 53 | // If file isn't created yet, buffer the comment 54 | if f.bufWriter == nil { 55 | f.pendingWrites = append(f.pendingWrites, fmt.Sprintf("; %s", comment)) 56 | return nil 57 | } 58 | // File is already created, write directly 59 | _, err := fmt.Fprintf(f.bufWriter, "; %s", comment) 60 | return err 61 | } 62 | 63 | // WriteCommentKey writes a key-value comment pair to the zone file. 64 | // The comment is formatted as "; key: value\n". 65 | func (f *File) WriteCommentKey(key, value string) error { 66 | return f.WriteComment(fmt.Sprintf("%s: %s\n", key, value)) 67 | } 68 | 69 | // ErrFileClosed is returned when attempting to write to a file that has been closed. 70 | var ErrFileClosed = errors.New("file is already closed") 71 | 72 | // fileReady ensures the file is created and ready for writing. 73 | // It creates the temporary file, sets up compression, and writes initial metadata. 74 | // This function is safe to call multiple times. 75 | func (f *File) fileReady() error { 76 | var err error 77 | if f.closed { 78 | return ErrFileClosed 79 | } 80 | if f.bufWriter == nil { 81 | f.fileWriter, err = os.Create(f.filenameTmp) 82 | if err != nil { 83 | return err 84 | } 85 | f.gzWriter = gzip.NewWriter(f.fileWriter) 86 | f.gzWriter.ModTime = time.Now() 87 | f.gzWriter.Name = fmt.Sprintf("%s.zone", f.zone[:len(f.zone)-1]) 88 | f.bufWriter = bufio.NewWriter(f.gzWriter) 89 | 90 | // Write timestamp and zone metadata 91 | _, err = fmt.Fprintf(f.bufWriter, "; timestamp: %s\n", time.Now().Format(time.RFC3339)) 92 | if err != nil { 93 | return err 94 | } 95 | _, err = fmt.Fprintf(f.bufWriter, "; zone: %s\n", f.zone) 96 | if err != nil { 97 | return err 98 | } 99 | 100 | // Write all buffered comments 101 | for _, comment := range f.pendingWrites { 102 | _, err = fmt.Fprintf(f.bufWriter, "%s", comment) 103 | if err != nil { 104 | return err 105 | } 106 | } 107 | // Clear the buffer 108 | f.pendingWrites = nil 109 | } 110 | return nil 111 | } 112 | 113 | // AddRR adds a record to a zone file 114 | func (f *File) AddRR(rr dns.RR) error { 115 | // create file here on first rr 116 | err := f.fileReady() 117 | if err != nil { 118 | return err 119 | } 120 | 121 | _, err = fmt.Fprintf(f.bufWriter, "%s\n", rr.String()) 122 | if err != nil { 123 | return err 124 | } 125 | f.records++ 126 | return nil 127 | } 128 | 129 | // Abort cancels the zone file creation and removes any temporary files. 130 | // It sets the record count to 0 to ensure the file is deleted rather than saved. 131 | func (f *File) Abort() error { 132 | f.records = 0 // forces finish to remove the file 133 | return f.Finish() 134 | } 135 | 136 | // Finish adds closing comments and flushes and closes all buffers/files 137 | func (f *File) Finish() error { 138 | if f.closed { 139 | return nil 140 | } 141 | 142 | // If no file was created (no records were added), just mark as closed 143 | if f.bufWriter == nil { 144 | f.closed = true 145 | return nil 146 | } 147 | 148 | // function to finish/close/safe the files when done 149 | if f.records > 1 { 150 | // save record count comment at end of zone file 151 | err := f.WriteCommentKey("records", fmt.Sprintf("%d", f.records)) 152 | if err != nil { 153 | return err 154 | } 155 | } 156 | var err error 157 | if f.bufWriter != nil { 158 | err = f.bufWriter.Flush() 159 | if err != nil { 160 | return err 161 | } 162 | err = f.gzWriter.Flush() 163 | if err != nil { 164 | return err 165 | } 166 | err = f.gzWriter.Close() 167 | if err != nil { 168 | return err 169 | } 170 | err = f.fileWriter.Close() 171 | if err != nil { 172 | return err 173 | } 174 | } 175 | if f.records > 0 { 176 | err = os.Rename(f.filenameTmp, f.filename) 177 | } else { 178 | err = os.Remove(f.filenameTmp) 179 | } 180 | if err != nil { 181 | return err 182 | } 183 | f.closed = true 184 | return nil 185 | } 186 | -------------------------------------------------------------------------------- /resolver/context_test.go: -------------------------------------------------------------------------------- 1 | package resolver 2 | 3 | import ( 4 | "context" 5 | "testing" 6 | "time" 7 | 8 | "github.com/miekg/dns" 9 | ) 10 | 11 | func TestResolverContextCancellation(t *testing.T) { 12 | resolver := New() 13 | 14 | t.Run("Resolve_CancelledContext", func(t *testing.T) { 15 | ctx, cancel := context.WithCancel(context.Background()) 16 | cancel() 17 | 18 | _, err := resolver.Resolve(ctx, "google.com", dns.TypeA) 19 | if err == nil { 20 | t.Error("Expected error due to cancelled context, but got nil") 21 | } 22 | t.Logf("Got error (as expected): %v", err) 23 | }) 24 | 25 | t.Run("ResolveAll_CancelledContext", func(t *testing.T) { 26 | ctx, cancel := context.WithCancel(context.Background()) 27 | cancel() 28 | 29 | _, err := resolver.ResolveAll(ctx, "google.com", dns.TypeA) 30 | if err == nil { 31 | t.Error("Expected error due to cancelled context, but got nil") 32 | } 33 | t.Logf("Got error (as expected): %v", err) 34 | }) 35 | 36 | t.Run("LookupIP_CancelledContext", func(t *testing.T) { 37 | ctx, cancel := context.WithCancel(context.Background()) 38 | cancel() 39 | 40 | _, err := resolver.LookupIP(ctx, "google.com") 41 | if err == nil { 42 | t.Error("Expected error due to cancelled context, but got nil") 43 | } 44 | t.Logf("Got error (as expected): %v", err) 45 | }) 46 | 47 | t.Run("LookupIPAll_CancelledContext", func(t *testing.T) { 48 | ctx, cancel := context.WithCancel(context.Background()) 49 | cancel() 50 | 51 | _, err := resolver.LookupIPAll(ctx, "google.com") 52 | if err == nil { 53 | t.Error("Expected error due to cancelled context, but got nil") 54 | } 55 | t.Logf("Got error (as expected): %v", err) 56 | }) 57 | } 58 | 59 | func TestResolverContextTimeout(t *testing.T) { 60 | resolver := New() 61 | 62 | t.Run("Resolve_ShortTimeout", func(t *testing.T) { 63 | ctx, cancel := context.WithTimeout(context.Background(), 1*time.Millisecond) 64 | defer cancel() 65 | 66 | _, err := resolver.Resolve(ctx, "google.com", dns.TypeA) 67 | if err == nil { 68 | t.Error("Expected error due to context timeout, but got nil") 69 | } 70 | t.Logf("Got error (as expected): %v", err) 71 | }) 72 | 73 | t.Run("ResolveAll_ShortTimeout", func(t *testing.T) { 74 | ctx, cancel := context.WithTimeout(context.Background(), 1*time.Millisecond) 75 | defer cancel() 76 | 77 | _, err := resolver.ResolveAll(ctx, "google.com", dns.TypeA) 78 | if err == nil { 79 | t.Error("Expected error due to context timeout, but got nil") 80 | } 81 | t.Logf("Got error (as expected): %v", err) 82 | }) 83 | 84 | t.Run("LookupIP_ShortTimeout", func(t *testing.T) { 85 | ctx, cancel := context.WithTimeout(context.Background(), 1*time.Millisecond) 86 | defer cancel() 87 | 88 | _, err := resolver.LookupIP(ctx, "google.com") 89 | if err == nil { 90 | t.Error("Expected error due to context timeout, but got nil") 91 | } 92 | t.Logf("Got error (as expected): %v", err) 93 | }) 94 | 95 | t.Run("LookupIPAll_ShortTimeout", func(t *testing.T) { 96 | ctx, cancel := context.WithTimeout(context.Background(), 1*time.Millisecond) 97 | defer cancel() 98 | 99 | _, err := resolver.LookupIPAll(ctx, "google.com") 100 | if err == nil { 101 | t.Error("Expected error due to context timeout, but got nil") 102 | } 103 | t.Logf("Got error (as expected): %v", err) 104 | }) 105 | } 106 | 107 | func TestResolverContextCancellationDuringQuery(t *testing.T) { 108 | resolver := NewWithTimeout(10 * time.Second) 109 | 110 | t.Run("CancelDuringResolve", func(t *testing.T) { 111 | ctx, cancel := context.WithCancel(context.Background()) 112 | 113 | done := make(chan struct{}) 114 | started := make(chan struct{}) 115 | var err error 116 | 117 | go func() { 118 | defer close(done) 119 | close(started) // Signal that the goroutine has started 120 | // Use a domain that doesn't exist to force multiple recursive queries 121 | // This increases the chance of cancellation during resolution 122 | _, err = resolver.Resolve(ctx, "nonexistent.test.invalid", dns.TypeA) 123 | }() 124 | 125 | // Wait for the goroutine to actually start the query 126 | <-started 127 | // Add a small delay to let the query start, then cancel 128 | time.Sleep(10 * time.Millisecond) 129 | cancel() 130 | 131 | select { 132 | case <-done: 133 | // Test passes if either: 134 | // 1. Context was cancelled (err contains "context canceled") 135 | // 2. Query completed with NXDOMAIN or other DNS error 136 | // Both outcomes demonstrate the resolver handles context correctly 137 | t.Logf("Context cancellation handled: %v", err) 138 | case <-time.After(5 * time.Second): 139 | t.Error("Query did not complete within timeout after context cancellation") 140 | } 141 | }) 142 | 143 | t.Run("CancelDuringResolveAll", func(t *testing.T) { 144 | ctx, cancel := context.WithCancel(context.Background()) 145 | 146 | done := make(chan struct{}) 147 | started := make(chan struct{}) 148 | var err error 149 | 150 | go func() { 151 | defer close(done) 152 | close(started) // Signal that the goroutine has started 153 | // Use a domain that doesn't exist to force multiple recursive queries 154 | // This increases the chance of cancellation during resolution 155 | _, err = resolver.ResolveAll(ctx, "nonexistent.test.invalid", dns.TypeA) 156 | }() 157 | 158 | // Wait for the goroutine to actually start the query 159 | <-started 160 | // Add a small delay to let the query start, then cancel 161 | time.Sleep(10 * time.Millisecond) 162 | cancel() 163 | 164 | select { 165 | case <-done: 166 | // Test passes if either: 167 | // 1. Context was cancelled (err contains "context canceled") 168 | // 2. Query completed with NXDOMAIN or other DNS error 169 | // Both outcomes demonstrate the resolver handles context correctly 170 | t.Logf("Context cancellation handled: %v", err) 171 | case <-time.After(5 * time.Second): 172 | t.Error("Query did not complete within timeout after context cancellation") 173 | } 174 | }) 175 | } 176 | -------------------------------------------------------------------------------- /main.go: -------------------------------------------------------------------------------- 1 | // Package main implements ALLXFR, a tool that performs DNS zone transfers (AXFR) 2 | // against root zone servers and attempts opportunistic zone transfers for every 3 | // nameserver IP to discover publicly available zone data. 4 | package main 5 | 6 | import ( 7 | "context" 8 | "flag" 9 | "fmt" 10 | "log" 11 | "os" 12 | "strings" 13 | "time" 14 | 15 | "github.com/lanrat/allxfr/resolver" 16 | "github.com/lanrat/allxfr/status" 17 | "github.com/lanrat/allxfr/zone" 18 | 19 | "github.com/lanrat/allxfr/psl" 20 | 21 | "golang.org/x/sync/errgroup" 22 | ) 23 | 24 | var ( 25 | parallel = flag.Uint("parallel", 10, "number of parallel zone transfers to perform") 26 | saveDir = flag.String("out", "zones", "directory to save found zones in") 27 | verbose = flag.Bool("verbose", false, "enable verbose output") 28 | zonefile = flag.String("zonefile", "", "use the provided zonefile instead of getting the root zonefile") 29 | saveAll = flag.Bool("save-all", false, "attempt AXFR from every nameserver for a given zone and save all answers") 30 | usePSL = flag.Bool("psl", false, "attempt AXFR from zones listed in the public suffix list") 31 | ixfr = flag.Bool("ixfr", false, "attempt an IXFR instead of AXFR") 32 | dryRun = flag.Bool("dry-run", false, "only test if xfr is allowed by retrieving one envelope") 33 | retry = flag.Int("retry", 3, "number of times to retry failed operations") 34 | overwrite = flag.Bool("overwrite", false, "if zone already exists on disk, overwrite it with newer data") 35 | statusAddr = flag.String("status-listen", "", "enable HTTP status server on specified [IP:]port (e.g., '8080', '127.0.0.1:8080', '[::1]:8080')") 36 | showVersion = flag.Bool("version", false, "print version and exit") // Show version 37 | 38 | ) 39 | 40 | var ( 41 | version = "dev" // Version string, set at build time 42 | totalXFR uint32 43 | resolve *resolver.Resolver 44 | statusServer *status.StatusServer 45 | ) 46 | 47 | const ( 48 | globalTimeout = 15 * time.Second 49 | ) 50 | 51 | // main is the entry point for the ALLXFR application. 52 | // It parses command-line flags, initializes the resolver and status server, 53 | // obtains zone data (from root AXFR, zonefile, or PSL), and orchestrates 54 | // parallel zone transfer attempts across all discovered nameservers. 55 | func main() { 56 | flag.Parse() 57 | if *showVersion { 58 | fmt.Println(version) 59 | return 60 | } 61 | if *retry < 1 { 62 | log.Fatal("retry must be positive") 63 | } 64 | 65 | // Start HTTP status server if address is specified 66 | if *statusAddr != "" { 67 | statusServer = status.StartStatusServer(*statusAddr) 68 | } 69 | 70 | resolve = resolver.New() 71 | start := time.Now() 72 | var z zone.Zone 73 | var err error 74 | 75 | if len(*zonefile) > 1 { 76 | // zone file is provided 77 | v("parsing zonefile: %q\n", *zonefile) 78 | z, err = zone.ParseZoneFile(*zonefile) 79 | check(err) 80 | } else if len(*zonefile) == 0 && flag.NArg() == 0 { 81 | // get zone file from root AXFR 82 | // not all the root nameservers allow AXFR, try them until we find one that does 83 | for _, ns := range resolver.RootServerNames { 84 | v("trying root nameserver %s", ns) 85 | startTime := time.Now() 86 | z, err = zone.RootAXFR(ns) 87 | if err == nil { 88 | took := time.Since(startTime).Round(time.Millisecond) 89 | log.Printf("ROOT %s xfr size: %d records in %s \n", ns, z.Records, took.String()) 90 | break 91 | } 92 | } 93 | } 94 | 95 | if flag.NArg() > 0 { 96 | for _, domain := range flag.Args() { 97 | z.AddNS(domain, "") 98 | } 99 | } 100 | 101 | if z.CountNS() == 0 { 102 | log.Fatal("Got empty zone") 103 | } 104 | 105 | if *usePSL { 106 | pslDomains, err := psl.GetDomains() 107 | check(err) 108 | for _, domain := range pslDomains { 109 | z.AddNS(domain, "") 110 | } 111 | v("added %d domains from PSL\n", len(pslDomains)) 112 | } 113 | 114 | if statusServer != nil { 115 | statusServer.IncrementTotalZones(uint32(z.CountNS())) 116 | } 117 | 118 | // create output dir if does not exist 119 | if !*dryRun { 120 | if _, err := os.Stat(*saveDir); os.IsNotExist(err) { 121 | err = os.MkdirAll(*saveDir, os.ModePerm) 122 | check(err) 123 | } 124 | } 125 | 126 | if *verbose { 127 | z.PrintTree() 128 | } 129 | 130 | ctx := context.Background() 131 | 132 | zoneChan := z.GetNameChan() 133 | var g errgroup.Group 134 | 135 | // start workers 136 | for i := uint(0); i < *parallel; i++ { 137 | g.Go(func() error { return worker(ctx, z, zoneChan) }) 138 | } 139 | 140 | err = g.Wait() 141 | check(err) 142 | took := time.Since(start).Round(time.Millisecond) 143 | log.Printf("%d / %d transferred in %s\n", totalXFR, len(z.NS), took.String()) 144 | v("exiting normally\n") 145 | } 146 | 147 | // worker processes domains from the channel and attempts zone transfers. 148 | // It receives domain names from the channel and calls axfrWorker to attempt 149 | // zone transfers for each domain. Updates the status server with transfer progress. 150 | func worker(ctx context.Context, z zone.Zone, c chan string) error { 151 | for { 152 | domain, more := <-c 153 | if !more { 154 | return nil 155 | } 156 | 157 | // Update status server with new domain discovered 158 | if statusServer != nil { 159 | statusServer.StartTransfer(domain) 160 | } 161 | 162 | err := axfrWorker(ctx, z, domain) 163 | if err != nil { 164 | if statusServer != nil { 165 | statusServer.FailTransfer(domain, err.Error()) 166 | } 167 | continue 168 | } 169 | 170 | // If no error occurred, the domain processing is complete 171 | // Success/failure status is handled within axfr function based on actual transfers 172 | } 173 | } 174 | 175 | // check is a utility function that terminates the program with log.Fatal 176 | // if the provided error is not nil. Used for handling critical errors. 177 | func check(err error) { 178 | if err != nil { 179 | log.Fatal(err) 180 | } 181 | } 182 | 183 | // v prints verbose output if the verbose flag is enabled. 184 | // It formats the message and prefixes each line with a tab for indentation. 185 | func v(format string, v ...interface{}) { 186 | if *verbose { 187 | line := fmt.Sprintf(format, v...) 188 | lines := strings.ReplaceAll(line, "\n", "\n\t") 189 | log.Print(lines) 190 | } 191 | } 192 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | cloud.google.com/go/compute/metadata v0.2.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k= 2 | github.com/ProtonMail/go-crypto v0.0.0-20230217124315-7d5c6f04bbb8/go.mod h1:I0gYDMZ6Z5GRU7l58bNFSkPTFN6Yl12dsUlAZ8xy98g= 3 | github.com/bwesterb/go-ristretto v1.2.0/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7NFEuV9ekS419A0= 4 | github.com/cloudflare/circl v1.1.0/go.mod h1:prBCrKB9DV4poKZY1l9zBXg2QJY7mvgRvtMxxK7fi4I= 5 | github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U= 6 | github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk= 7 | github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY= 8 | github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE= 9 | github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE= 10 | github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY= 11 | github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY= 12 | github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI= 13 | github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY= 14 | github.com/google/go-github/v50 v50.2.0/go.mod h1:VBY8FB6yPIjrtKhozXv4FQupxKLS6H4m6xFZlT43q8Q= 15 | github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU= 16 | github.com/miekg/dns v1.1.67 h1:kg0EHj0G4bfT5/oOys6HhZw4vmMlnoZ+gDu8tJ/AlI0= 17 | github.com/miekg/dns v1.1.67/go.mod h1:fujopn7TB3Pu3JM69XaawiU0wqjpL9/8xGop5UrTPps= 18 | github.com/weppos/publicsuffix-go v0.40.2 h1:LlnoSH0Eqbsi3ReXZWBKCK5lHyzf3sc1JEHH1cnlfho= 19 | github.com/weppos/publicsuffix-go v0.40.2/go.mod h1:XsLZnULC3EJ1Gvk9GVjuCTZ8QUu9ufE4TZpOizDShko= 20 | github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY= 21 | golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= 22 | golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc= 23 | golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU= 24 | golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc= 25 | golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU= 26 | golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8= 27 | golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M= 28 | golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4= 29 | golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs= 30 | golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs= 31 | golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c= 32 | golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c= 33 | golang.org/x/mod v0.26.0 h1:EGMPT//Ezu+ylkCijjPc+f4Aih7sZvaAr+O3EHBxvZg= 34 | golang.org/x/mod v0.26.0/go.mod h1:/j6NAhSk8iQ723BGAUyoAcn7SlD7s15Dp9Nd/SfeaFQ= 35 | golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks= 36 | golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= 37 | golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg= 38 | golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c= 39 | golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs= 40 | golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc= 41 | golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg= 42 | golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk= 43 | golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44= 44 | golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM= 45 | golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE= 46 | golang.org/x/net 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golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= 68 | golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= 69 | golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= 70 | golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA= 71 | golang.org/x/sys v0.34.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k= 72 | golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE= 73 | golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo= 74 | golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8= 75 | golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k= 76 | golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U= 77 | golang.org/x/term v0.8.0/go.mod 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golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE= 90 | golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU= 91 | golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU= 92 | golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI= 93 | golang.org/x/text v0.27.0 h1:4fGWRpyh641NLlecmyl4LOe6yDdfaYNrGb2zdfo4JV4= 94 | golang.org/x/text v0.27.0/go.mod h1:1D28KMCvyooCX9hBiosv5Tz/+YLxj0j7XhWjpSUF7CU= 95 | golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ= 96 | golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo= 97 | golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc= 98 | golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU= 99 | golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58= 100 | golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk= 101 | golang.org/x/tools v0.35.0 h1:mBffYraMEf7aa0sB+NuKnuCy8qI/9Bughn8dC2Gu5r0= 102 | golang.org/x/tools v0.35.0/go.mod h1:NKdj5HkL/73byiZSJjqJgKn3ep7KjFkBOkR/Hps3VPw= 103 | golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= 104 | golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= 105 | google.golang.org/appengine v1.6.7/go.mod h1:8WjMMxjGQR8xUklV/ARdw2HLXBOI7O7uCIDZVag1xfc= 106 | google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw= 107 | google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc= 108 | google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I= 109 | google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos= 110 | -------------------------------------------------------------------------------- /status/status.go: -------------------------------------------------------------------------------- 1 | // Package status provides HTTP endpoints and tracking for DNS zone transfer operations. 2 | // It maintains real-time statistics about transfer progress, success/failure rates, 3 | // and active transfers, while also providing a cleanup mechanism to prevent memory 4 | // leaks from stale transfer entries. The package exposes JSON APIs for monitoring 5 | // the ALLXFR application's performance and progress. 6 | package status 7 | 8 | import ( 9 | "encoding/json" 10 | "log" 11 | "math" 12 | "net" 13 | "net/http" 14 | "strings" 15 | "sync" 16 | "sync/atomic" 17 | "time" 18 | ) 19 | 20 | // StatusServer tracks the status of zone transfers and provides HTTP endpoints 21 | type StatusServer struct { 22 | startTime time.Time 23 | totalZones uint32 24 | completed uint32 25 | failed uint32 26 | active sync.Map // map[string]time.Time - active zone transfers 27 | activeCount uint32 28 | mu sync.RWMutex 29 | recentFailed []string // recent failures for debugging 30 | } 31 | 32 | // StatusResponse represents the JSON response for status endpoint 33 | type StatusResponse struct { 34 | StartTime time.Time `json:"start_time"` 35 | Runtime string `json:"runtime"` 36 | TotalZones uint32 `json:"total_zones"` 37 | Completed uint32 `json:"completed"` 38 | Failed uint32 `json:"failed"` 39 | Active uint32 `json:"active"` 40 | Remaining uint32 `json:"remaining"` 41 | SuccessRate float64 `json:"success_rate"` 42 | TransferRate float64 `json:"transfer_rate_per_minute"` 43 | RecentFailed []string `json:"recent_failed,omitempty"` 44 | ActiveZones []string `json:"active_zones,omitempty"` 45 | } 46 | 47 | // HealthResponse represents the JSON response for health endpoint 48 | type HealthResponse struct { 49 | Status string `json:"status"` 50 | Message string `json:"message"` 51 | } 52 | 53 | // NewStatusServer creates a new status server instance 54 | func NewStatusServer() *StatusServer { 55 | s := &StatusServer{ 56 | startTime: time.Now(), 57 | totalZones: 0, // Will be updated as domains are discovered 58 | recentFailed: make([]string, 0), 59 | } 60 | 61 | // Start cleanup goroutine to prevent memory leaks from stale active entries 62 | go s.cleanupStaleEntries() 63 | 64 | return s 65 | } 66 | 67 | // IncrementTotalZones increments the total zone count as domains are discovered 68 | func (s *StatusServer) IncrementTotalZones(change uint32) { 69 | atomic.AddUint32(&s.totalZones, change) 70 | } 71 | 72 | // StartTransfer marks a zone as actively being transferred 73 | func (s *StatusServer) StartTransfer(zone string) { 74 | s.active.Store(zone, time.Now()) 75 | atomic.AddUint32(&s.activeCount, 1) 76 | } 77 | 78 | // CompleteTransfer marks a zone transfer as completed 79 | func (s *StatusServer) CompleteTransfer(zone string) { 80 | // Only process if the zone is still active (avoid double-counting) 81 | if _, exists := s.active.LoadAndDelete(zone); exists { 82 | atomic.AddUint32(&s.activeCount, ^uint32(0)) // decrement 83 | atomic.AddUint32(&s.completed, 1) 84 | } 85 | } 86 | 87 | // FailTransfer marks a zone transfer as failed 88 | func (s *StatusServer) FailTransfer(zone string, reason string) { 89 | // Only process if the zone is still active (avoid double-counting) 90 | if _, exists := s.active.LoadAndDelete(zone); exists { 91 | atomic.AddUint32(&s.activeCount, ^uint32(0)) // decrement 92 | atomic.AddUint32(&s.failed, 1) 93 | 94 | // Add to recent failures (keep last 10) 95 | s.mu.Lock() 96 | failureEntry := zone 97 | if reason != "" { 98 | failureEntry += ": " + reason 99 | } 100 | s.recentFailed = append(s.recentFailed, failureEntry) 101 | if len(s.recentFailed) > 10 { 102 | s.recentFailed = s.recentFailed[1:] 103 | } 104 | s.mu.Unlock() 105 | } 106 | } 107 | 108 | // GetStatus returns current status information 109 | func (s *StatusServer) GetStatus() StatusResponse { 110 | s.mu.RLock() 111 | recentFailed := make([]string, len(s.recentFailed)) 112 | copy(recentFailed, s.recentFailed) 113 | s.mu.RUnlock() 114 | 115 | completed := atomic.LoadUint32(&s.completed) 116 | failed := atomic.LoadUint32(&s.failed) 117 | active := atomic.LoadUint32(&s.activeCount) 118 | totalZones := atomic.LoadUint32(&s.totalZones) 119 | 120 | // Collect active zone names 121 | var activeZones []string 122 | s.active.Range(func(key, value interface{}) bool { 123 | if zone, ok := key.(string); ok { 124 | activeZones = append(activeZones, zone) 125 | } 126 | return true // continue iteration 127 | }) 128 | 129 | runtime := time.Since(s.startTime) 130 | remaining := uint32(0) 131 | if totalZones > completed+failed { 132 | remaining = totalZones - completed - failed 133 | } 134 | 135 | var successRate float64 136 | if completed+failed > 0 { 137 | successRate = math.Round(float64(completed)/float64(completed+failed)*100*100) / 100 138 | } 139 | 140 | var transferRate float64 141 | if runtime.Minutes() > 0 { 142 | transferRate = math.Round(float64(completed)/runtime.Minutes()*100) / 100 143 | } 144 | 145 | return StatusResponse{ 146 | StartTime: s.startTime, 147 | Runtime: runtime.Round(time.Second).String(), 148 | TotalZones: totalZones, 149 | Completed: completed, 150 | Failed: failed, 151 | Active: active, 152 | Remaining: remaining, 153 | SuccessRate: successRate, 154 | TransferRate: transferRate, 155 | RecentFailed: recentFailed, 156 | ActiveZones: activeZones, 157 | } 158 | } 159 | 160 | // cleanupStaleEntries periodically removes entries from the active map that have been 161 | // active for too long (likely due to missed FailTransfer/CompleteTransfer calls) 162 | func (s *StatusServer) cleanupStaleEntries() { 163 | ticker := time.NewTicker(5 * time.Minute) 164 | defer ticker.Stop() 165 | 166 | for range ticker.C { 167 | now := time.Now() 168 | staleThreshold := 10 * time.Minute // Consider entries stale after 10 minutes 169 | 170 | s.active.Range(func(key, value interface{}) bool { 171 | if startTime, ok := value.(time.Time); ok { 172 | if now.Sub(startTime) > staleThreshold { 173 | // Remove stale entry and count it as failed 174 | if _, exists := s.active.LoadAndDelete(key); exists { 175 | atomic.AddUint32(&s.activeCount, ^uint32(0)) // decrement 176 | atomic.AddUint32(&s.failed, 1) 177 | 178 | s.mu.Lock() 179 | zone := key.(string) 180 | failureEntry := zone + ": stale transfer (cleanup)" 181 | s.recentFailed = append(s.recentFailed, failureEntry) 182 | if len(s.recentFailed) > 10 { 183 | s.recentFailed = s.recentFailed[1:] 184 | } 185 | s.mu.Unlock() 186 | } 187 | } 188 | } 189 | return true // continue iteration 190 | }) 191 | } 192 | } 193 | 194 | // HTTP Handlers 195 | 196 | func (s *StatusServer) statusHandler(w http.ResponseWriter, r *http.Request) { 197 | if s == nil { 198 | http.Error(w, "Status server not initialized", http.StatusInternalServerError) 199 | return 200 | } 201 | 202 | status := s.GetStatus() 203 | w.Header().Set("Content-Type", "application/json") 204 | if err := json.NewEncoder(w).Encode(status); err != nil { 205 | http.Error(w, "Failed to encode status", http.StatusInternalServerError) 206 | return 207 | } 208 | } 209 | 210 | func (s *StatusServer) healthHandler(w http.ResponseWriter, r *http.Request) { 211 | health := HealthResponse{ 212 | Status: "ok", 213 | Message: "ALLXFR is running", 214 | } 215 | 216 | w.Header().Set("Content-Type", "application/json") 217 | if err := json.NewEncoder(w).Encode(health); err != nil { 218 | http.Error(w, "Failed to encode health response", http.StatusInternalServerError) 219 | return 220 | } 221 | } 222 | 223 | func (s *StatusServer) progressHandler(w http.ResponseWriter, r *http.Request) { 224 | if s == nil { 225 | http.Error(w, "Status server not initialized", http.StatusInternalServerError) 226 | return 227 | } 228 | 229 | status := s.GetStatus() 230 | 231 | // Simplified progress response 232 | attempted := status.Completed + status.Failed 233 | var percentage float64 234 | if status.TotalZones > 0 { 235 | percentage = math.Round(float64(attempted)/float64(status.TotalZones)*100*100) / 100 236 | } 237 | 238 | progress := map[string]interface{}{ 239 | "completed": status.Completed, 240 | "failed": status.Failed, 241 | "attempted": attempted, 242 | "total": status.TotalZones, 243 | "remaining": status.Remaining, 244 | "active": status.Active, 245 | "percentage": percentage, 246 | } 247 | 248 | w.Header().Set("Content-Type", "application/json") 249 | if err := json.NewEncoder(w).Encode(progress); err != nil { 250 | http.Error(w, "Failed to encode progress response", http.StatusInternalServerError) 251 | return 252 | } 253 | } 254 | 255 | // StartStatusServer starts the HTTP status server in a separate goroutine 256 | func StartStatusServer(addr string) *StatusServer { 257 | statusServer := NewStatusServer() 258 | 259 | mux := http.NewServeMux() 260 | mux.HandleFunc("/status", statusServer.statusHandler) 261 | mux.HandleFunc("/health", statusServer.healthHandler) 262 | mux.HandleFunc("/progress", statusServer.progressHandler) 263 | 264 | // Parse address to handle both "port" and "ip:port" formats 265 | var serverAddr string 266 | if strings.Contains(addr, ":") { 267 | // Already in host:port format 268 | serverAddr = addr 269 | } else { 270 | // Just port, bind to all interfaces 271 | serverAddr = ":" + addr 272 | } 273 | 274 | server := &http.Server{ 275 | Addr: serverAddr, 276 | Handler: mux, 277 | } 278 | 279 | go func() { 280 | host, port, err := net.SplitHostPort(serverAddr) 281 | if err != nil { 282 | log.Printf("Status server starting on %s", serverAddr) 283 | } else { 284 | if host == "" { 285 | host = "localhost" 286 | } 287 | log.Printf("Status server starting on %s", serverAddr) 288 | log.Printf("Available endpoints:") 289 | log.Printf(" http://%s:%s/status - Full status information", host, port) 290 | log.Printf(" http://%s:%s/progress - Progress summary", host, port) 291 | log.Printf(" http://%s:%s/health - Health check", host, port) 292 | } 293 | 294 | if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed { 295 | log.Printf("Status server error: %v", err) 296 | } 297 | }() 298 | return statusServer 299 | } 300 | -------------------------------------------------------------------------------- /axfr.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "context" 5 | "errors" 6 | "fmt" 7 | "log" 8 | "net" 9 | "os" 10 | "path" 11 | "sync/atomic" 12 | "time" 13 | 14 | "github.com/lanrat/allxfr/save" 15 | "github.com/lanrat/allxfr/zone" 16 | 17 | "github.com/miekg/dns" 18 | ) 19 | 20 | // ErrAxfrUnsupported indicates that the nameserver does not support AXFR requests. 21 | // This is a common response when zone transfers are disabled on the server. 22 | var ErrAxfrUnsupported = errors.New("AXFR Unsupported") 23 | 24 | // ErrorAxfrUnsupportedWrap wraps DNS errors with ErrAxfrUnsupported when 25 | // the error indicates that AXFR is refused or not authorized. 26 | // It specifically handles DNS response codes 5 (Refused) and 9 (Not Authorized). 27 | func ErrorAxfrUnsupportedWrap(err error) error { 28 | if err == nil { 29 | return nil 30 | } 31 | errStr := err.Error() 32 | // "bad xfr rcode: 5" - Refused 33 | if errStr == "dns: bad xfr rcode: 5" { 34 | err = fmt.Errorf("%w 'Refused': %w", ErrAxfrUnsupported, err) 35 | } 36 | //"bad xfr rcode: 9" - Not Authorized / Not Authenticated 37 | if errStr == "dns: bad xfr rcode: 9" { 38 | err = fmt.Errorf("%w 'Not Authorized': %w", ErrAxfrUnsupported, err) 39 | } 40 | return err 41 | } 42 | 43 | // axfrWorker attempts zone transfers for a domain using all available nameservers and IPs. 44 | // It tries both glue records from the zone data and performs additional NS queries 45 | // to discover non-glue nameserver IPs. Returns nil if any transfer succeeds. 46 | func axfrWorker(ctx context.Context, z zone.Zone, domain string) error { 47 | attemptedIPs := make(map[string]bool) 48 | domain = dns.Fqdn(domain) 49 | var err error 50 | //var records int64 51 | var anySuccess bool 52 | for _, nameserver := range z.NS[domain] { 53 | // Check for context cancellation 54 | select { 55 | case <-ctx.Done(): 56 | return ctx.Err() 57 | default: 58 | } 59 | for _, ip := range z.IP[nameserver] { 60 | ipString := ip.To16().String() 61 | if !attemptedIPs[ipString] { 62 | attemptedIPs[ipString] = true 63 | anySuccess, err = axfrRetry(ctx, ip, domain, nameserver) 64 | if err != nil { 65 | continue 66 | } 67 | if anySuccess { 68 | // got the zone 69 | return nil 70 | } 71 | } 72 | } 73 | } 74 | 75 | // query NS and run axfr on missing IPs 76 | var qNameservers []string 77 | for try := 0; try < *retry; try++ { 78 | result, err := resolve.Resolve(ctx, domain, dns.TypeNS) 79 | if err != nil { 80 | v("[%s] %s", domain, err) 81 | } else { 82 | for _, rr := range result.Answer { 83 | if ns, ok := rr.(*dns.NS); ok { 84 | qNameservers = append(qNameservers, ns.Ns) 85 | } 86 | } 87 | break 88 | } 89 | select { 90 | case <-ctx.Done(): 91 | return ctx.Err() 92 | case <-time.After(1 * time.Second): 93 | } 94 | } 95 | 96 | for _, nameserver := range qNameservers { 97 | // Check for context cancellation 98 | select { 99 | case <-ctx.Done(): 100 | return ctx.Err() 101 | default: 102 | } 103 | var qIPs []net.IP 104 | for try := 0; try < *retry; try++ { 105 | qIPs, err = resolve.LookupIPAll(ctx, nameserver) 106 | if err != nil { 107 | v("[%s] %s", domain, err) 108 | } else { 109 | break 110 | } 111 | select { 112 | case <-ctx.Done(): 113 | return ctx.Err() 114 | case <-time.After(1 * time.Second): 115 | } 116 | } 117 | 118 | for _, ip := range qIPs { 119 | // Check for context cancellation 120 | select { 121 | case <-ctx.Done(): 122 | return ctx.Err() 123 | default: 124 | } 125 | ipString := ip.To16().String() 126 | if !attemptedIPs[ipString] { 127 | attemptedIPs[ipString] = true 128 | v("[%s] trying non-glue AXFR: %s %s", domain, nameserver, ip.String()) 129 | anySuccess, err = axfrRetry(ctx, ip, domain, nameserver) 130 | if err != nil { 131 | continue 132 | } 133 | if anySuccess { 134 | // got the zone 135 | return nil 136 | } 137 | } 138 | } 139 | } 140 | 141 | // If no successful transfers occurred, mark domain as failed 142 | if !anySuccess && statusServer != nil { 143 | statusServer.FailTransfer(domain, "no successful zone transfers") 144 | } 145 | 146 | return nil 147 | } 148 | 149 | // axfrRetry attempts a zone transfer with retry logic. 150 | // It retries failed transfers up to the configured retry count, but skips 151 | // retries if the nameserver explicitly doesn't support AXFR. 152 | // Returns (success, error) where success indicates if any records were transferred. 153 | func axfrRetry(ctx context.Context, ip net.IP, domain, nameserver string) (bool, error) { 154 | var err error 155 | var records int64 156 | var anySuccess bool 157 | 158 | for try := 0; try < *retry; try++ { 159 | records, err = axfr(ctx, domain, nameserver, ip) 160 | if err != nil { 161 | v("[%s] %s", domain, err) 162 | // if axfr is unsupported by NS, then move on, otherwise retry 163 | if errors.Is(err, ErrAxfrUnsupported) { 164 | err = nil 165 | // skip remaining tries with this IP 166 | break 167 | } 168 | } else { 169 | if records != 0 { 170 | anySuccess = true 171 | break 172 | } 173 | } 174 | select { 175 | case <-ctx.Done(): 176 | return anySuccess, ctx.Err() 177 | case <-time.After(1 * time.Second): 178 | } 179 | } 180 | if !*saveAll && records != 0 { 181 | return anySuccess, nil 182 | } 183 | if err != nil { 184 | return anySuccess, err 185 | } 186 | 187 | return anySuccess, err 188 | } 189 | 190 | // axfr performs a single zone transfer attempt and logs the result. 191 | // It calls axfrToFile to perform the actual transfer and updates global 192 | // transfer statistics and status server on success. 193 | // Returns the number of records transferred. 194 | func axfr(ctx context.Context, domain, nameserver string, ip net.IP) (int64, error) { 195 | startTime := time.Now() 196 | records, err := axfrToFile(ctx, domain, ip, nameserver) 197 | if err == nil && records > 0 { 198 | took := time.Since(startTime).Round(time.Millisecond) 199 | log.Printf("[%s] %s (%s) xfr size: %d records in %s\n", domain, nameserver, ip.String(), records, took.String()) 200 | atomic.AddUint32(&totalXFR, 1) 201 | 202 | // Update status server on successful transfer 203 | if statusServer != nil { 204 | statusServer.CompleteTransfer(domain) 205 | } 206 | } 207 | return records, err 208 | } 209 | 210 | // InContext performs a DNS zone transfer using the provided context and connection address. 211 | // It creates a TCP connection with context support and returns a channel of DNS envelopes 212 | // containing the transferred zone records. The transfer respects the context's cancellation 213 | // and uses global timeout settings for the connection operations. 214 | // It wraps miekg/dns.Transfer.In() with a Context 215 | func InContext(ctx context.Context, q *dns.Msg, a string) (env chan *dns.Envelope, err error) { 216 | // Create a dialer with context 217 | dialer := &net.Dialer{ 218 | Timeout: globalTimeout, 219 | } 220 | 221 | // Dial with context 222 | conn, err := dialer.DialContext(ctx, "tcp", a) 223 | if err != nil { 224 | return nil, err 225 | } 226 | 227 | // Create DNS connection wrapper 228 | dnsConn := &dns.Conn{Conn: conn} 229 | 230 | // Create transfer with pre-configured connection 231 | transfer := &dns.Transfer{ 232 | Conn: dnsConn, 233 | DialTimeout: globalTimeout, 234 | ReadTimeout: globalTimeout, 235 | WriteTimeout: globalTimeout, 236 | } 237 | return transfer.In(q, a) 238 | } 239 | 240 | // axfrToFile performs an AXFR or IXFR request and saves the results to a compressed file. 241 | // It handles file creation, DNS transfer setup with timeouts, and processes each 242 | // envelope of records. Returns the number of records transferred or -1 if the file 243 | // already exists and overwrite is disabled. 244 | func axfrToFile(ctx context.Context, zone string, ip net.IP, nameserver string) (int64, error) { 245 | zone = dns.Fqdn(zone) 246 | 247 | m := new(dns.Msg) 248 | if *ixfr { 249 | m.SetIxfr(zone, 0, "", "") 250 | } else { 251 | m.SetQuestion(zone, dns.TypeAXFR) 252 | } 253 | 254 | env, err := InContext(ctx, m, net.JoinHostPort(ip.String(), "53")) 255 | if err != nil { 256 | // skip on this error 257 | err = fmt.Errorf("transfer error from zone: %s ip: %s: %w", zone, ip.String(), err) 258 | v("[%s] %s", zone, err) 259 | return 0, nil 260 | } 261 | 262 | // get ready to save file 263 | var filename string 264 | if *saveAll { 265 | filename = path.Join(*saveDir, fmt.Sprintf("%s_%s_%s_zone.gz", zone, nameserver, ip.String())) 266 | } else { 267 | filename = path.Join(*saveDir, fmt.Sprintf("%s.zone.gz", zone[:len(zone)-1])) 268 | } 269 | if !*overwrite { 270 | if _, err := os.Stat(filename); err == nil || !os.IsNotExist(err) { 271 | v("[%s] file %q exists, skipping", zone, filename) 272 | return -1, nil 273 | } 274 | } 275 | 276 | var envelope int64 277 | zonefile := save.New(zone, filename) 278 | defer func() { 279 | err = zonefile.WriteCommentKey("envelopes", fmt.Sprintf("%d", envelope)) 280 | if err != nil { 281 | panic(err) 282 | } 283 | err := zonefile.Finish() 284 | if err != nil { 285 | panic(err) 286 | } 287 | }() 288 | err = zonefile.WriteComment("Generated by ALLXFR (https://github.com/lanrat/allxfr)\n") 289 | if err != nil { 290 | return zonefile.Records(), err 291 | } 292 | err = zonefile.WriteCommentKey("nameserver", nameserver) 293 | if err != nil { 294 | return zonefile.Records(), err 295 | } 296 | err = zonefile.WriteCommentKey("nameserverIP", ip.String()) 297 | if err != nil { 298 | return zonefile.Records(), err 299 | } 300 | axfrType := "AXFR" 301 | if *ixfr { 302 | axfrType = "IXFR" 303 | } 304 | err = zonefile.WriteCommentKey("xfr", axfrType) 305 | if err != nil { 306 | return zonefile.Records(), err 307 | } 308 | 309 | for e := range env { 310 | // Check for context cancellation 311 | select { 312 | case <-ctx.Done(): 313 | return zonefile.Records(), ctx.Err() 314 | default: 315 | } 316 | if e.Error != nil { 317 | err = ErrorAxfrUnsupportedWrap(e.Error) 318 | // skip on this error 319 | err = fmt.Errorf("transfer envelope error from zone: %s ip: %s (rec: %d, envelope: %d): %w", zone, ip.String(), zonefile.Records(), envelope, err) 320 | return zonefile.Records(), err 321 | } 322 | // zonefile will not write anything to disk unless it has been provided records to write. 323 | if *dryRun && len(e.RR) > 0 { 324 | return int64(len(e.RR)), nil 325 | } 326 | for _, rr := range e.RR { 327 | // create file here on first iteration of loop 328 | err := zonefile.AddRR(rr) 329 | if err != nil { 330 | return zonefile.Records(), err 331 | } 332 | } 333 | envelope++ 334 | } 335 | 336 | return zonefile.Records(), err 337 | } 338 | -------------------------------------------------------------------------------- /resolver/resolver_test.go: -------------------------------------------------------------------------------- 1 | package resolver 2 | 3 | import ( 4 | "context" 5 | "net" 6 | "sort" 7 | "testing" 8 | 9 | "github.com/miekg/dns" 10 | ) 11 | 12 | func TestResolverA(t *testing.T) { 13 | resolver := New() 14 | testDomains := []string{ 15 | "google.com", 16 | "github.com", 17 | "cloudflare.com", 18 | } 19 | 20 | ctx := context.Background() 21 | 22 | for _, domain := range testDomains { 23 | t.Run(domain, func(t *testing.T) { 24 | result, err := resolver.Resolve(ctx, domain, dns.TypeA) 25 | if err != nil { 26 | t.Fatalf("Failed to resolve %s: %v", domain, err) 27 | } 28 | 29 | if len(result.Answer) == 0 { 30 | t.Fatalf("No A records found for %s", domain) 31 | } 32 | 33 | var resolverIPs []net.IP 34 | for _, rr := range result.Answer { 35 | if a, ok := rr.(*dns.A); ok { 36 | resolverIPs = append(resolverIPs, a.A) 37 | } 38 | } 39 | 40 | if len(resolverIPs) == 0 { 41 | t.Fatalf("No A records in answer section for %s", domain) 42 | } 43 | 44 | systemIPs, err := net.LookupIP(domain) 45 | if err != nil { 46 | t.Fatalf("System lookup failed for %s: %v", domain, err) 47 | } 48 | 49 | var systemIPv4 []net.IP 50 | for _, ip := range systemIPs { 51 | if ip.To4() != nil { 52 | systemIPv4 = append(systemIPv4, ip) 53 | } 54 | } 55 | 56 | if len(systemIPv4) == 0 { 57 | t.Skipf("No IPv4 addresses from system resolver for %s", domain) 58 | } 59 | 60 | if !compareIPSets(resolverIPs, systemIPv4) { 61 | t.Logf("Resolver IPs: %v", resolverIPs) 62 | t.Logf("System IPs: %v", systemIPv4) 63 | t.Logf("Note: IP sets differ - this may be due to different DNS servers or timing") 64 | } 65 | }) 66 | } 67 | } 68 | 69 | func TestResolverAAAA(t *testing.T) { 70 | resolver := New() 71 | testDomains := []string{ 72 | "google.com", 73 | "github.com", 74 | "cloudflare.com", 75 | } 76 | 77 | ctx := context.Background() 78 | 79 | for _, domain := range testDomains { 80 | t.Run(domain, func(t *testing.T) { 81 | result, err := resolver.Resolve(ctx, domain, dns.TypeAAAA) 82 | if err != nil { 83 | t.Logf("No AAAA records for %s: %v", domain, err) 84 | return 85 | } 86 | 87 | var resolverIPs []net.IP 88 | for _, rr := range result.Answer { 89 | if aaaa, ok := rr.(*dns.AAAA); ok { 90 | resolverIPs = append(resolverIPs, aaaa.AAAA) 91 | } 92 | } 93 | 94 | systemIPs, err := net.LookupIP(domain) 95 | if err != nil { 96 | t.Fatalf("System lookup failed for %s: %v", domain, err) 97 | } 98 | 99 | var systemIPv6 []net.IP 100 | for _, ip := range systemIPs { 101 | if ip.To4() == nil && ip.To16() != nil { 102 | systemIPv6 = append(systemIPv6, ip) 103 | } 104 | } 105 | 106 | if len(resolverIPs) == 0 && len(systemIPv6) == 0 { 107 | t.Logf("No AAAA records for %s (expected)", domain) 108 | return 109 | } 110 | 111 | if len(resolverIPs) > 0 && len(systemIPv6) > 0 { 112 | if !compareIPSets(resolverIPs, systemIPv6) { 113 | t.Logf("Resolver IPv6: %v", resolverIPs) 114 | t.Logf("System IPv6: %v", systemIPv6) 115 | t.Logf("Note: IPv6 sets differ - this may be due to different DNS servers or timing") 116 | } 117 | } 118 | }) 119 | } 120 | } 121 | 122 | func TestResolverNS(t *testing.T) { 123 | resolver := New() 124 | testDomains := []string{ 125 | "google.com", 126 | "github.com", 127 | } 128 | 129 | ctx := context.Background() 130 | 131 | for _, domain := range testDomains { 132 | t.Run(domain, func(t *testing.T) { 133 | result, err := resolver.Resolve(ctx, domain, dns.TypeNS) 134 | if err != nil { 135 | t.Fatalf("Failed to resolve %s NS: %v", domain, err) 136 | } 137 | 138 | if len(result.Answer) == 0 { 139 | t.Fatalf("No NS records found for %s", domain) 140 | } 141 | 142 | var nsRecords []string 143 | for _, rr := range result.Answer { 144 | if ns, ok := rr.(*dns.NS); ok { 145 | nsRecords = append(nsRecords, ns.Ns) 146 | } 147 | } 148 | 149 | if len(nsRecords) == 0 { 150 | t.Fatalf("No NS records in answer section for %s", domain) 151 | } 152 | 153 | systemNS, err := net.LookupNS(domain) 154 | if err != nil { 155 | t.Fatalf("System NS lookup failed for %s: %v", domain, err) 156 | } 157 | 158 | var systemNSNames []string 159 | for _, ns := range systemNS { 160 | systemNSNames = append(systemNSNames, ns.Host) 161 | } 162 | 163 | if !compareStringSets(nsRecords, systemNSNames) { 164 | t.Logf("Resolver NS: %v", nsRecords) 165 | t.Logf("System NS: %v", systemNSNames) 166 | t.Logf("Note: NS sets differ - this may be due to different DNS servers or timing") 167 | } 168 | }) 169 | } 170 | } 171 | 172 | func TestResolverCNAME(t *testing.T) { 173 | resolver := New() 174 | testDomains := []string{ 175 | "www.github.com", 176 | } 177 | 178 | ctx := context.Background() 179 | 180 | for _, domain := range testDomains { 181 | t.Run(domain, func(t *testing.T) { 182 | result, err := resolver.Resolve(ctx, domain, dns.TypeCNAME) 183 | if err != nil { 184 | t.Fatalf("Failed to resolve %s CNAME: %v", domain, err) 185 | } 186 | 187 | var cnameTarget string 188 | for _, rr := range result.Answer { 189 | if cname, ok := rr.(*dns.CNAME); ok { 190 | cnameTarget = cname.Target 191 | break 192 | } 193 | } 194 | 195 | systemCNAME, err := net.LookupCNAME(domain) 196 | if err != nil { 197 | if len(result.Answer) == 0 { 198 | t.Skipf("No CNAME record for %s (expected)", domain) 199 | return 200 | } 201 | t.Fatalf("System CNAME lookup failed for %s: %v", domain, err) 202 | } 203 | 204 | if cnameTarget != "" && systemCNAME != "" { 205 | if cnameTarget != systemCNAME { 206 | t.Logf("Resolver CNAME: %s", cnameTarget) 207 | t.Logf("System CNAME: %s", systemCNAME) 208 | t.Logf("Note: CNAME targets differ - this may be due to different DNS servers or timing") 209 | } 210 | } 211 | }) 212 | } 213 | } 214 | 215 | func TestResolverNXDOMAIN(t *testing.T) { 216 | resolver := New() 217 | nonexistentDomain := "this-does-not-exist-12345.com" 218 | 219 | ctx := context.Background() 220 | 221 | result, err := resolver.Resolve(ctx, nonexistentDomain, dns.TypeA) 222 | 223 | if err != nil { 224 | t.Fatalf("Unexpected error for NXDOMAIN: %v", err) 225 | } 226 | 227 | if result.Rcode != dns.RcodeNameError { 228 | t.Fatalf("Expected NXDOMAIN (RcodeNameError), got %d", result.Rcode) 229 | } 230 | } 231 | 232 | func TestRootServerResolution(t *testing.T) { 233 | t.Logf("Testing TestRootServerResolution") 234 | 235 | rootServers := getRootServers(context.Background()) 236 | if len(rootServers) == 0 { 237 | t.Fatal("No root servers resolved") 238 | } 239 | 240 | t.Logf("Resolved %d root servers", len(rootServers)) 241 | for i, server := range rootServers { 242 | if i < 5 { 243 | t.Logf("Root server %d: %s", i+1, server) 244 | } 245 | } 246 | } 247 | 248 | func compareIPSets(a, b []net.IP) bool { 249 | if len(a) != len(b) { 250 | return false 251 | } 252 | 253 | aStr := make([]string, len(a)) 254 | bStr := make([]string, len(b)) 255 | 256 | for i, ip := range a { 257 | aStr[i] = ip.String() 258 | } 259 | for i, ip := range b { 260 | bStr[i] = ip.String() 261 | } 262 | 263 | sort.Strings(aStr) 264 | sort.Strings(bStr) 265 | 266 | for i := range aStr { 267 | if aStr[i] != bStr[i] { 268 | return false 269 | } 270 | } 271 | 272 | return true 273 | } 274 | 275 | func compareStringSets(a, b []string) bool { 276 | if len(a) != len(b) { 277 | return false 278 | } 279 | 280 | aCopy := make([]string, len(a)) 281 | bCopy := make([]string, len(b)) 282 | copy(aCopy, a) 283 | copy(bCopy, b) 284 | 285 | sort.Strings(aCopy) 286 | sort.Strings(bCopy) 287 | 288 | for i := range aCopy { 289 | if aCopy[i] != bCopy[i] { 290 | return false 291 | } 292 | } 293 | 294 | return true 295 | } 296 | 297 | func TestResolverResolveAll(t *testing.T) { 298 | resolver := New() 299 | testDomains := []string{ 300 | "google.com", 301 | "github.com", 302 | } 303 | 304 | ctx := context.Background() 305 | 306 | for _, domain := range testDomains { 307 | t.Run(domain, func(t *testing.T) { 308 | resultAll, err := resolver.ResolveAll(ctx, domain, dns.TypeA) 309 | if err != nil { 310 | t.Fatalf("Failed to resolve %s with ResolveAll: %v", domain, err) 311 | } 312 | 313 | resultNormal, err := resolver.Resolve(ctx, domain, dns.TypeA) 314 | if err != nil { 315 | t.Fatalf("Failed to resolve %s with Resolve: %v", domain, err) 316 | } 317 | 318 | if len(resultAll.Answer) == 0 { 319 | t.Fatalf("No A records found for %s with ResolveAll", domain) 320 | } 321 | 322 | if len(resultNormal.Answer) == 0 { 323 | t.Fatalf("No A records found for %s with Resolve", domain) 324 | } 325 | 326 | var allIPs []net.IP 327 | for _, rr := range resultAll.Answer { 328 | if a, ok := rr.(*dns.A); ok { 329 | allIPs = append(allIPs, a.A) 330 | } 331 | } 332 | 333 | var normalIPs []net.IP 334 | for _, rr := range resultNormal.Answer { 335 | if a, ok := rr.(*dns.A); ok { 336 | normalIPs = append(normalIPs, a.A) 337 | } 338 | } 339 | 340 | if len(allIPs) < len(normalIPs) { 341 | t.Fatalf("ResolveAll returned fewer IPs (%d) than Resolve (%d) for %s", 342 | len(allIPs), len(normalIPs), domain) 343 | } 344 | 345 | t.Logf("ResolveAll found %d A records for %s", len(allIPs), domain) 346 | t.Logf("Resolve found %d A records for %s", len(normalIPs), domain) 347 | }) 348 | } 349 | } 350 | 351 | func TestResolverLookupIP(t *testing.T) { 352 | resolver := New() 353 | testDomains := []string{ 354 | "google.com", 355 | "github.com", 356 | "cloudflare.com", 357 | } 358 | 359 | ctx := context.Background() 360 | 361 | for _, domain := range testDomains { 362 | t.Run(domain, func(t *testing.T) { 363 | resolverIPs, err := resolver.LookupIP(ctx, domain) 364 | if err != nil { 365 | t.Fatalf("Failed to lookup IP for %s: %v", domain, err) 366 | } 367 | 368 | if len(resolverIPs) == 0 { 369 | t.Fatalf("No IP addresses found for %s", domain) 370 | } 371 | 372 | systemIPs, err := net.LookupIP(domain) 373 | if err != nil { 374 | t.Fatalf("System lookup failed for %s: %v", domain, err) 375 | } 376 | 377 | if len(systemIPs) == 0 { 378 | t.Fatalf("No IP addresses from system resolver for %s", domain) 379 | } 380 | 381 | var resolverIPv4, resolverIPv6 []net.IP 382 | for _, ip := range resolverIPs { 383 | if ip.To4() != nil { 384 | resolverIPv4 = append(resolverIPv4, ip) 385 | } else if ip.To16() != nil { 386 | resolverIPv6 = append(resolverIPv6, ip) 387 | } 388 | } 389 | 390 | var systemIPv4, systemIPv6 []net.IP 391 | for _, ip := range systemIPs { 392 | if ip.To4() != nil { 393 | systemIPv4 = append(systemIPv4, ip) 394 | } else if ip.To16() != nil { 395 | systemIPv6 = append(systemIPv6, ip) 396 | } 397 | } 398 | 399 | t.Logf("Resolver found %d IPv4 and %d IPv6 addresses for %s", 400 | len(resolverIPv4), len(resolverIPv6), domain) 401 | t.Logf("System found %d IPv4 and %d IPv6 addresses for %s", 402 | len(systemIPv4), len(systemIPv6), domain) 403 | 404 | if len(resolverIPv4) == 0 && len(systemIPv4) > 0 { 405 | t.Errorf("Resolver found no IPv4 addresses but system found %d for %s", 406 | len(systemIPv4), domain) 407 | } 408 | }) 409 | } 410 | } 411 | 412 | func TestResolverLookupIPAll(t *testing.T) { 413 | resolver := New() 414 | testDomains := []string{ 415 | "google.com", 416 | "github.com", 417 | "cloudflare.com", 418 | } 419 | ctx := context.Background() 420 | 421 | for _, domain := range testDomains { 422 | t.Run(domain, func(t *testing.T) { 423 | allIPs, err := resolver.LookupIPAll(ctx, domain) 424 | if err != nil { 425 | t.Fatalf("Failed to lookup IP with LookupIPAll for %s: %v", domain, err) 426 | } 427 | 428 | normalIPs, err := resolver.LookupIP(ctx, domain) 429 | if err != nil { 430 | t.Fatalf("Failed to lookup IP with LookupIP for %s: %v", domain, err) 431 | } 432 | 433 | if len(allIPs) == 0 { 434 | t.Fatalf("No IP addresses found with LookupIPAll for %s", domain) 435 | } 436 | 437 | if len(normalIPs) == 0 { 438 | t.Fatalf("No IP addresses found with LookupIP for %s", domain) 439 | } 440 | 441 | var allIPv4, allIPv6 []net.IP 442 | for _, ip := range allIPs { 443 | if ip.To4() != nil { 444 | allIPv4 = append(allIPv4, ip) 445 | } else if ip.To16() != nil { 446 | allIPv6 = append(allIPv6, ip) 447 | } 448 | } 449 | 450 | var normalIPv4, normalIPv6 []net.IP 451 | for _, ip := range normalIPs { 452 | if ip.To4() != nil { 453 | normalIPv4 = append(normalIPv4, ip) 454 | } else if ip.To16() != nil { 455 | normalIPv6 = append(normalIPv6, ip) 456 | } 457 | } 458 | 459 | if len(allIPv4) < len(normalIPv4) { 460 | t.Fatalf("LookupIPAll returned fewer IPv4 addresses (%d) than LookupIP (%d) for %s", 461 | len(allIPv4), len(normalIPv4), domain) 462 | } 463 | 464 | if len(allIPv6) < len(normalIPv6) { 465 | t.Fatalf("LookupIPAll returned fewer IPv6 addresses (%d) than LookupIP (%d) for %s", 466 | len(allIPv6), len(normalIPv6), domain) 467 | } 468 | 469 | t.Logf("LookupIPAll found %d IPv4 and %d IPv6 addresses for %s", 470 | len(allIPv4), len(allIPv6), domain) 471 | t.Logf("LookupIP found %d IPv4 and %d IPv6 addresses for %s", 472 | len(normalIPv4), len(normalIPv6), domain) 473 | }) 474 | } 475 | } 476 | -------------------------------------------------------------------------------- /resolver/resolver.go: -------------------------------------------------------------------------------- 1 | // Package resolver provides a recursive DNS resolver that handles missing glue records 2 | // and implements caching for improved performance. 3 | package resolver 4 | 5 | import ( 6 | "context" 7 | "fmt" 8 | "net" 9 | "strconv" 10 | "strings" 11 | "sync" 12 | "time" 13 | 14 | "github.com/miekg/dns" 15 | ) 16 | 17 | const ( 18 | maxRecursionDepth = 30 19 | defaultQueryTimeout = 5 * time.Second 20 | maxFailures = 5 // Circuit breaker threshold 21 | circuitBreakerTTL = 60 * time.Second // How long to avoid failed nameservers 22 | ) 23 | 24 | // RootServerNames contains the hostnames of the DNS root servers. 25 | // These are the authoritative nameservers for the root zone of the DNS hierarchy. 26 | var RootServerNames = []string{ 27 | "a.root-servers.net", 28 | "b.root-servers.net", 29 | "c.root-servers.net", 30 | "d.root-servers.net", 31 | "e.root-servers.net", 32 | "f.root-servers.net", 33 | "g.root-servers.net", 34 | "h.root-servers.net", 35 | "i.root-servers.net", 36 | "j.root-servers.net", 37 | "k.root-servers.net", 38 | "l.root-servers.net", 39 | "m.root-servers.net", 40 | } 41 | 42 | var ( 43 | rootServers []string 44 | rootServersOnce sync.Once 45 | ) 46 | 47 | // Resolver implements a recursive DNS resolver with caching and missing glue record handling. 48 | // It follows the DNS resolution process by starting from root servers and following 49 | // referrals until it reaches an authoritative answer. 50 | type Resolver struct { 51 | client dns.Client 52 | cache *dnsCache 53 | rttStats map[string]*rttStats // RTT statistics per nameserver 54 | rttMutex sync.RWMutex // Protects rttStats map 55 | } 56 | 57 | type rttStats struct { 58 | avgRTT time.Duration 59 | samples int 60 | lastSeen time.Time 61 | failures int 62 | lastFailed time.Time // When the last failure occurred 63 | mu sync.Mutex 64 | } 65 | 66 | // Result represents the outcome of a DNS query operation. 67 | // It contains the response sections and metadata from the DNS resolution process. 68 | type Result struct { 69 | Answer []dns.RR // Resource records that directly answer the query 70 | Authority []dns.RR // Authority section containing NS records for delegation 71 | Additional []dns.RR // Additional section containing glue records 72 | Rcode int // DNS response code (e.g., NOERROR, NXDOMAIN) 73 | Authoritative bool // Whether the response came from an authoritative server 74 | } 75 | 76 | // New creates a new DNS resolver with default cache size. 77 | // The resolver is configured with appropriate timeouts and will handle 78 | // missing glue records automatically. 79 | func New() *Resolver { 80 | return NewWithCacheSize(defaultCacheSize, defaultQueryTimeout) 81 | } 82 | 83 | // NewWithTimeout creates a new DNS resolver with the specified timeout. 84 | // The timeout parameter determines how long to wait for DNS responses. 85 | func NewWithTimeout(timeout time.Duration) *Resolver { 86 | return NewWithCacheSize(defaultCacheSize, timeout) 87 | } 88 | 89 | // NewWithCacheSize creates a new DNS resolver with the specified cache size. 90 | // The cacheSize parameter determines how many DNS responses can be cached 91 | // using an LRU eviction policy. 92 | func NewWithCacheSize(cacheSize int, timeout time.Duration) *Resolver { 93 | return &Resolver{ 94 | client: dns.Client{ 95 | Timeout: timeout, 96 | Dialer: &net.Dialer{ 97 | Timeout: timeout, 98 | }, 99 | }, 100 | cache: newDNSCache(cacheSize), 101 | rttStats: make(map[string]*rttStats), 102 | } 103 | } 104 | 105 | // getRootServers returns the cached list of root server IP addresses. 106 | // It uses sync.Once to ensure root servers are resolved only once per program execution. 107 | func getRootServers(ctx context.Context) []string { 108 | rootServersOnce.Do(func() { 109 | rootServers = resolveRootServers(ctx) 110 | }) 111 | return rootServers 112 | } 113 | 114 | // resolveRootServers resolves all root server hostnames to IP addresses in parallel. 115 | // It looks up both IPv4 and IPv6 addresses for each root server and returns 116 | // them as "ip:port" strings ready for DNS queries. 117 | func resolveRootServers(ctx context.Context) []string { 118 | var servers []string 119 | var mu sync.Mutex 120 | var wg sync.WaitGroup 121 | 122 | // Create a context with timeout for root server resolution 123 | resolveCtx, cancel := context.WithTimeout(ctx, 10*time.Second) 124 | defer cancel() 125 | 126 | // Resolve all root servers in parallel 127 | for _, name := range RootServerNames { 128 | wg.Add(1) 129 | go func(hostname string) { 130 | defer wg.Done() 131 | 132 | netResolver := &net.Resolver{} 133 | ips, err := netResolver.LookupIPAddr(resolveCtx, hostname) 134 | if err != nil { 135 | return 136 | } 137 | 138 | mu.Lock() 139 | for _, ip := range ips { 140 | servers = append(servers, net.JoinHostPort(ip.IP.String(), "53")) 141 | } 142 | mu.Unlock() 143 | }(name) 144 | } 145 | wg.Wait() 146 | 147 | return servers 148 | } 149 | 150 | // Resolve performs a recursive DNS lookup for the given domain and query type. 151 | // It starts from the root servers and follows the DNS delegation chain until 152 | // it finds an authoritative answer. Results are cached based on their TTL values. 153 | // 154 | // The domain parameter should be a valid domain name (will be converted to FQDN). 155 | // The qtype parameter specifies the DNS record type (e.g., dns.TypeA, dns.TypeAAAA). 156 | // 157 | // Returns a Result containing the DNS response sections and metadata, or an error 158 | // if the resolution fails. 159 | func (r *Resolver) Resolve(ctx context.Context, domain string, qtype uint16) (*Result, error) { 160 | domain = dns.Fqdn(domain) 161 | 162 | cacheKey := r.makeCacheKey(domain, qtype) 163 | if cached, found := r.cache.get(cacheKey); found { 164 | return cached, nil 165 | } 166 | 167 | result, err := r.resolveRecursive(ctx, domain, qtype, getRootServers(ctx), 0) 168 | if err != nil { 169 | return nil, err 170 | } 171 | 172 | if result != nil { 173 | ttl := r.calculateTTL(result) 174 | if ttl > 0 { 175 | switch result.Rcode { 176 | case dns.RcodeSuccess: 177 | r.cache.put(cacheKey, result, ttl) 178 | case dns.RcodeNameError: 179 | // Cache NXDOMAIN responses with shorter TTL 180 | negativeTTL := ttl 181 | if negativeTTL > 5*time.Minute { 182 | negativeTTL = 5 * time.Minute 183 | } 184 | r.cache.putNegative(cacheKey, result, negativeTTL) 185 | } 186 | } 187 | } 188 | 189 | return result, nil 190 | } 191 | 192 | // ResolveAll performs a recursive DNS lookup for the given domain and query type, 193 | // querying ALL authoritative nameservers and returning the union of all answers. 194 | // Unlike Resolve which returns after the first successful response, ResolveAll 195 | // queries every authoritative nameserver at each level and merges all results. 196 | // 197 | // The domain parameter should be a valid domain name (will be converted to FQDN). 198 | // The qtype parameter specifies the DNS record type (e.g., dns.TypeA, dns.TypeAAAA). 199 | // 200 | // Returns a Result containing the merged DNS response sections from all nameservers, 201 | // or an error if the resolution fails. 202 | func (r *Resolver) ResolveAll(ctx context.Context, domain string, qtype uint16) (*Result, error) { 203 | domain = dns.Fqdn(domain) 204 | 205 | cacheKey := r.makeCacheKey(domain+"_ALL", qtype) 206 | if cached, found := r.cache.get(cacheKey); found { 207 | return cached, nil 208 | } 209 | 210 | result, err := r.resolveRecursiveAll(ctx, domain, qtype, getRootServers(ctx), 0) 211 | if err != nil { 212 | return nil, err 213 | } 214 | 215 | if result != nil { 216 | ttl := r.calculateTTL(result) 217 | if ttl > 0 { 218 | switch result.Rcode { 219 | case dns.RcodeSuccess: 220 | r.cache.put(cacheKey, result, ttl) 221 | case dns.RcodeNameError: 222 | // Cache NXDOMAIN responses with shorter TTL 223 | negativeTTL := ttl 224 | if negativeTTL > 5*time.Minute { 225 | negativeTTL = 5 * time.Minute 226 | } 227 | r.cache.putNegative(cacheKey, result, negativeTTL) 228 | } 229 | } 230 | } 231 | 232 | return result, nil 233 | } 234 | 235 | // LookupIP looks up host using the resolver and returns a slice of that host's IP addresses. 236 | // It works like net.LookupIP but uses the recursive resolver instead of the system resolver. 237 | // The function queries both A and AAAA records and returns all found IP addresses. 238 | func (r *Resolver) LookupIP(ctx context.Context, host string) ([]net.IP, error) { 239 | var ips []net.IP 240 | 241 | // Query A records (IPv4) 242 | resultA, err := r.Resolve(ctx, host, dns.TypeA) 243 | if err == nil && resultA.Rcode == dns.RcodeSuccess { 244 | for _, rr := range resultA.Answer { 245 | if a, ok := rr.(*dns.A); ok { 246 | ips = append(ips, a.A) 247 | } 248 | } 249 | } 250 | 251 | // Query AAAA records (IPv6) 252 | resultAAAA, err := r.Resolve(ctx, host, dns.TypeAAAA) 253 | if err == nil && resultAAAA.Rcode == dns.RcodeSuccess { 254 | for _, rr := range resultAAAA.Answer { 255 | if aaaa, ok := rr.(*dns.AAAA); ok { 256 | ips = append(ips, aaaa.AAAA) 257 | } 258 | } 259 | } 260 | 261 | if len(ips) == 0 { 262 | return nil, fmt.Errorf("no IP addresses found for %s", host) 263 | } 264 | 265 | return ips, nil 266 | } 267 | 268 | // LookupIPAll looks up host using the resolver and returns a slice of that host's IP addresses 269 | // from ALL authoritative nameservers. It works like LookupIP but uses ResolveAll instead of Resolve, 270 | // ensuring that IP addresses from all nameservers are collected and returned. 271 | // The function queries both A and AAAA records in parallel and returns all found IP addresses. 272 | func (r *Resolver) LookupIPAll(ctx context.Context, host string) ([]net.IP, error) { 273 | // Query A and AAAA records in parallel 274 | type resolveResult struct { 275 | result *Result 276 | err error 277 | } 278 | 279 | aChan := make(chan resolveResult, 1) 280 | aaaaChan := make(chan resolveResult, 1) 281 | 282 | // Query A records (IPv4) from all nameservers 283 | go func() { 284 | result, err := r.ResolveAll(ctx, host, dns.TypeA) 285 | aChan <- resolveResult{result: result, err: err} 286 | }() 287 | 288 | // Query AAAA records (IPv6) from all nameservers 289 | go func() { 290 | result, err := r.ResolveAll(ctx, host, dns.TypeAAAA) 291 | aaaaChan <- resolveResult{result: result, err: err} 292 | }() 293 | 294 | var ips []net.IP 295 | 296 | // Collect A and AAAA record results with context cancellation support 297 | for i := 0; i < 2; i++ { 298 | select { 299 | case aResult := <-aChan: 300 | if aResult.err == nil && aResult.result.Rcode == dns.RcodeSuccess { 301 | for _, rr := range aResult.result.Answer { 302 | if a, ok := rr.(*dns.A); ok { 303 | ips = append(ips, a.A) 304 | } 305 | } 306 | } 307 | case aaaaResult := <-aaaaChan: 308 | if aaaaResult.err == nil && aaaaResult.result.Rcode == dns.RcodeSuccess { 309 | for _, rr := range aaaaResult.result.Answer { 310 | if aaaa, ok := rr.(*dns.AAAA); ok { 311 | ips = append(ips, aaaa.AAAA) 312 | } 313 | } 314 | } 315 | case <-ctx.Done(): 316 | return nil, ctx.Err() 317 | } 318 | } 319 | 320 | if len(ips) == 0 { 321 | return nil, fmt.Errorf("no IP addresses found for %s", host) 322 | } 323 | 324 | return ips, nil 325 | } 326 | 327 | func (r *Resolver) makeCacheKey(domain string, qtype uint16) string { 328 | return domain + ":" + strconv.FormatUint(uint64(qtype), 10) 329 | } 330 | 331 | func (r *Resolver) updateRTT(nameserver string, rtt time.Duration, success bool) { 332 | r.rttMutex.Lock() 333 | stats, exists := r.rttStats[nameserver] 334 | if !exists { 335 | stats = &rttStats{} 336 | r.rttStats[nameserver] = stats 337 | } 338 | r.rttMutex.Unlock() 339 | 340 | stats.mu.Lock() 341 | defer stats.mu.Unlock() 342 | 343 | if success { 344 | stats.lastSeen = time.Now() 345 | stats.failures = 0 346 | 347 | if stats.samples == 0 { 348 | stats.avgRTT = rtt 349 | stats.samples = 1 350 | } else { 351 | // Exponential weighted moving average with alpha = 0.125 352 | stats.avgRTT = stats.avgRTT*7/8 + rtt/8 353 | stats.samples++ 354 | } 355 | } else { 356 | stats.failures++ 357 | stats.lastFailed = time.Now() 358 | } 359 | } 360 | 361 | func (r *Resolver) sortNameserversByRTT(nameservers []string) []string { 362 | if len(nameservers) <= 1 { 363 | return nameservers 364 | } 365 | 366 | type nsWithRTT struct { 367 | ns string 368 | rtt time.Duration 369 | failures int 370 | hasStat bool 371 | circuitOpen bool 372 | } 373 | 374 | var nsStats []nsWithRTT 375 | now := time.Now() 376 | r.rttMutex.RLock() 377 | for _, ns := range nameservers { 378 | stat := nsWithRTT{ns: ns} 379 | if stats, exists := r.rttStats[ns]; exists { 380 | stats.mu.Lock() 381 | stat.rtt = stats.avgRTT 382 | stat.failures = stats.failures 383 | stat.hasStat = true 384 | 385 | // Circuit breaker logic: avoid nameservers that have failed too many times recently 386 | if stats.failures >= maxFailures && 387 | now.Sub(stats.lastFailed) < circuitBreakerTTL { 388 | stat.circuitOpen = true 389 | } 390 | stats.mu.Unlock() 391 | } 392 | nsStats = append(nsStats, stat) 393 | } 394 | r.rttMutex.RUnlock() 395 | 396 | // Sort by: circuit breaker status, then failures, then RTT, then stats availability 397 | for i := 0; i < len(nsStats)-1; i++ { 398 | for j := i + 1; j < len(nsStats); j++ { 399 | // Always prefer nameservers with open circuits last 400 | if nsStats[i].circuitOpen && !nsStats[j].circuitOpen { 401 | nsStats[i], nsStats[j] = nsStats[j], nsStats[i] 402 | continue 403 | } 404 | if !nsStats[i].circuitOpen && nsStats[j].circuitOpen { 405 | continue 406 | } 407 | 408 | // Prefer nameservers with fewer failures 409 | if nsStats[i].failures > nsStats[j].failures { 410 | nsStats[i], nsStats[j] = nsStats[j], nsStats[i] 411 | continue 412 | } 413 | if nsStats[i].failures < nsStats[j].failures { 414 | continue 415 | } 416 | 417 | // If same failure count, prefer ones with stats 418 | if !nsStats[i].hasStat && nsStats[j].hasStat { 419 | nsStats[i], nsStats[j] = nsStats[j], nsStats[i] 420 | continue 421 | } 422 | if nsStats[i].hasStat && !nsStats[j].hasStat { 423 | continue 424 | } 425 | 426 | // If both have stats, prefer lower RTT 427 | if nsStats[i].hasStat && nsStats[j].hasStat && nsStats[i].rtt > nsStats[j].rtt { 428 | nsStats[i], nsStats[j] = nsStats[j], nsStats[i] 429 | } 430 | } 431 | } 432 | 433 | result := make([]string, len(nsStats)) 434 | for i, stat := range nsStats { 435 | result[i] = stat.ns 436 | } 437 | return result 438 | } 439 | 440 | func (r *Resolver) calculateTTL(result *Result) time.Duration { 441 | if result == nil { 442 | return 0 443 | } 444 | 445 | minTTL := uint32(3600) 446 | 447 | for _, rr := range result.Answer { 448 | if rr.Header().Ttl < minTTL { 449 | minTTL = rr.Header().Ttl 450 | } 451 | } 452 | 453 | for _, rr := range result.Authority { 454 | if rr.Header().Ttl < minTTL { 455 | minTTL = rr.Header().Ttl 456 | } 457 | // For NXDOMAIN, use SOA record's minimum TTL if available 458 | if result.Rcode == dns.RcodeNameError { 459 | if soa, ok := rr.(*dns.SOA); ok { 460 | if soa.Minttl < minTTL { 461 | minTTL = soa.Minttl 462 | } 463 | } 464 | } 465 | } 466 | 467 | if minTTL == 3600 && len(result.Answer) == 0 && len(result.Authority) == 0 { 468 | return 5 * time.Minute 469 | } 470 | 471 | if minTTL < 60 { 472 | minTTL = 60 473 | } 474 | 475 | return time.Duration(minTTL) * time.Second 476 | } 477 | 478 | func (r *Resolver) resolveRecursive(ctx context.Context, domain string, qtype uint16, nameservers []string, depth int) (*Result, error) { 479 | if depth > maxRecursionDepth { 480 | return nil, fmt.Errorf("maximum recursion depth exceeded") 481 | } 482 | 483 | if len(nameservers) == 0 { 484 | return nil, fmt.Errorf("no nameservers available") 485 | } 486 | 487 | // Sort nameservers by RTT for better performance 488 | sortedNS := r.sortNameserversByRTT(nameservers) 489 | 490 | for _, ns := range sortedNS { 491 | select { 492 | case <-ctx.Done(): 493 | return nil, ctx.Err() 494 | default: 495 | } 496 | 497 | result, err := r.queryNameserver(ctx, ns, domain, qtype) 498 | if err != nil { 499 | continue 500 | } 501 | 502 | if result.Rcode != dns.RcodeSuccess { 503 | if result.Rcode == dns.RcodeNameError { 504 | return result, nil 505 | } 506 | continue 507 | } 508 | 509 | if len(result.Answer) > 0 { 510 | result.Answer = r.followCNAME(ctx, result.Answer, qtype, depth) 511 | return result, nil 512 | } 513 | 514 | if len(result.Authority) > 0 { 515 | nsRecords := r.extractNSRecords(result.Authority) 516 | if len(nsRecords) == 0 { 517 | continue 518 | } 519 | 520 | nextNS := r.resolveNameservers(ctx, nsRecords, result.Additional) 521 | if len(nextNS) == 0 { 522 | continue 523 | } 524 | 525 | return r.resolveRecursive(ctx, domain, qtype, nextNS, depth+1) 526 | } 527 | } 528 | 529 | return nil, fmt.Errorf("no answer found for %s", domain) 530 | } 531 | 532 | func (r *Resolver) queryNameserver(ctx context.Context, nameserver, domain string, qtype uint16) (*Result, error) { 533 | if !strings.Contains(nameserver, ":") { 534 | nameserver = nameserver + ":53" 535 | } 536 | 537 | m := new(dns.Msg) 538 | m.SetQuestion(domain, qtype) 539 | m.RecursionDesired = false 540 | 541 | start := time.Now() 542 | resp, _, err := r.client.ExchangeContext(ctx, m, nameserver) 543 | rtt := time.Since(start) 544 | 545 | if err != nil { 546 | r.updateRTT(nameserver, 0, false) 547 | return nil, err 548 | } 549 | 550 | r.updateRTT(nameserver, rtt, true) 551 | 552 | return &Result{ 553 | Answer: resp.Answer, 554 | Authority: resp.Ns, 555 | Additional: resp.Extra, 556 | Rcode: resp.Rcode, 557 | Authoritative: resp.Authoritative, 558 | }, nil 559 | } 560 | 561 | func (r *Resolver) followCNAME(ctx context.Context, answers []dns.RR, originalType uint16, depth int) []dns.RR { 562 | result := make([]dns.RR, 0, len(answers)) 563 | 564 | for _, rr := range answers { 565 | select { 566 | case <-ctx.Done(): 567 | return result // Return what we have so far 568 | default: 569 | } 570 | 571 | result = append(result, rr) 572 | 573 | if cname, ok := rr.(*dns.CNAME); ok && originalType != dns.TypeCNAME { 574 | cnameResult, err := r.resolveRecursive(ctx, cname.Target, originalType, getRootServers(ctx), depth+1) 575 | if err == nil && len(cnameResult.Answer) > 0 { 576 | result = append(result, cnameResult.Answer...) 577 | } 578 | } 579 | } 580 | 581 | return result 582 | } 583 | 584 | func (r *Resolver) extractNSRecords(authority []dns.RR) []string { 585 | var nsRecords []string 586 | for _, rr := range authority { 587 | if ns, ok := rr.(*dns.NS); ok { 588 | nsRecords = append(nsRecords, dns.Fqdn(ns.Ns)) 589 | } 590 | } 591 | return nsRecords 592 | } 593 | 594 | func (r *Resolver) resolveNameservers(ctx context.Context, nsRecords []string, additional []dns.RR) []string { 595 | var nameservers []string 596 | var mu sync.Mutex 597 | 598 | // Build map of glue records 599 | additionalMap := make(map[string][]net.IP) 600 | for _, rr := range additional { 601 | switch rec := rr.(type) { 602 | case *dns.A: 603 | additionalMap[rec.Hdr.Name] = append(additionalMap[rec.Hdr.Name], rec.A) 604 | case *dns.AAAA: 605 | additionalMap[rec.Hdr.Name] = append(additionalMap[rec.Hdr.Name], rec.AAAA) 606 | } 607 | } 608 | 609 | // Collect nameservers with glue records first 610 | var missingGlue []string 611 | for _, nsName := range nsRecords { 612 | if ips, found := additionalMap[nsName]; found { 613 | mu.Lock() 614 | for _, ip := range ips { 615 | nameservers = append(nameservers, net.JoinHostPort(ip.String(), "53")) 616 | } 617 | mu.Unlock() 618 | } else { 619 | missingGlue = append(missingGlue, nsName) 620 | } 621 | } 622 | 623 | // Resolve missing glue records in parallel 624 | if len(missingGlue) > 0 { 625 | var wg sync.WaitGroup 626 | for _, nsName := range missingGlue { 627 | wg.Add(1) 628 | go func(hostname string) { 629 | defer wg.Done() 630 | timeoutCtx, cancel := context.WithTimeout(ctx, defaultQueryTimeout) 631 | defer cancel() 632 | 633 | resolver := &net.Resolver{} 634 | ips, err := resolver.LookupIPAddr(timeoutCtx, hostname) 635 | if err == nil { 636 | mu.Lock() 637 | for _, ip := range ips { 638 | nameservers = append(nameservers, net.JoinHostPort(ip.IP.String(), "53")) 639 | } 640 | mu.Unlock() 641 | } 642 | }(nsName) 643 | } 644 | wg.Wait() 645 | } 646 | 647 | return nameservers 648 | } 649 | 650 | // mergeResults combines multiple DNS query results into a single Result. 651 | // It deduplicates resource records and selects the best Rcode and Authoritative status. 652 | // Used by ResolveAll to combine responses from multiple nameservers. 653 | func mergeResults(results []*Result) *Result { 654 | if len(results) == 0 { 655 | return nil 656 | } 657 | 658 | merged := &Result{ 659 | Answer: []dns.RR{}, 660 | Authority: []dns.RR{}, 661 | Additional: []dns.RR{}, 662 | Rcode: dns.RcodeServerFailure, 663 | Authoritative: false, 664 | } 665 | 666 | rrSeen := make(map[string]bool) 667 | 668 | for _, result := range results { 669 | if result == nil { 670 | continue 671 | } 672 | 673 | if result.Rcode == dns.RcodeSuccess { 674 | merged.Rcode = dns.RcodeSuccess 675 | } else if merged.Rcode == dns.RcodeServerFailure && result.Rcode == dns.RcodeNameError { 676 | merged.Rcode = dns.RcodeNameError 677 | } 678 | 679 | if result.Authoritative { 680 | merged.Authoritative = true 681 | } 682 | 683 | for _, rr := range result.Answer { 684 | key := rr.String() 685 | if !rrSeen[key] { 686 | rrSeen[key] = true 687 | merged.Answer = append(merged.Answer, rr) 688 | } 689 | } 690 | 691 | for _, rr := range result.Authority { 692 | key := rr.String() 693 | if !rrSeen[key] { 694 | rrSeen[key] = true 695 | merged.Authority = append(merged.Authority, rr) 696 | } 697 | } 698 | 699 | for _, rr := range result.Additional { 700 | key := rr.String() 701 | if !rrSeen[key] { 702 | rrSeen[key] = true 703 | merged.Additional = append(merged.Additional, rr) 704 | } 705 | } 706 | } 707 | 708 | return merged 709 | } 710 | 711 | // resolveRecursiveAll performs recursive resolution by querying ALL nameservers 712 | // at each level and merging their responses, unlike resolveRecursive which stops 713 | // at the first successful response. 714 | func (r *Resolver) resolveRecursiveAll(ctx context.Context, domain string, qtype uint16, nameservers []string, depth int) (*Result, error) { 715 | if depth > maxRecursionDepth { 716 | return nil, fmt.Errorf("maximum recursion depth exceeded") 717 | } 718 | 719 | if len(nameservers) == 0 { 720 | return nil, fmt.Errorf("no nameservers available") 721 | } 722 | 723 | // Query all nameservers in parallel 724 | type queryResult struct { 725 | result *Result 726 | err error 727 | } 728 | 729 | resultChan := make(chan queryResult, len(nameservers)) 730 | 731 | // Start goroutines for each nameserver 732 | for _, ns := range nameservers { 733 | go func(nameserver string) { 734 | result, err := r.queryNameserver(ctx, nameserver, domain, qtype) 735 | resultChan <- queryResult{result: result, err: err} 736 | }(ns) 737 | } 738 | 739 | // Collect results from all goroutines 740 | var allResults []*Result 741 | var hasSuccessfulQuery bool 742 | 743 | for i := 0; i < len(nameservers); i++ { 744 | select { 745 | case qr := <-resultChan: 746 | if qr.err != nil { 747 | continue 748 | } 749 | hasSuccessfulQuery = true 750 | allResults = append(allResults, qr.result) 751 | case <-ctx.Done(): 752 | return nil, ctx.Err() 753 | } 754 | } 755 | 756 | if !hasSuccessfulQuery { 757 | return nil, fmt.Errorf("no nameservers responded for %s", domain) 758 | } 759 | 760 | merged := mergeResults(allResults) 761 | if merged == nil { 762 | return nil, fmt.Errorf("no valid responses for %s", domain) 763 | } 764 | 765 | if merged.Rcode != dns.RcodeSuccess { 766 | return merged, nil 767 | } 768 | 769 | if len(merged.Answer) > 0 { 770 | merged.Answer = r.followCNAME(ctx, merged.Answer, qtype, depth) 771 | return merged, nil 772 | } 773 | 774 | if len(merged.Authority) > 0 { 775 | nsRecords := r.extractNSRecords(merged.Authority) 776 | if len(nsRecords) == 0 { 777 | return merged, nil 778 | } 779 | 780 | nextNS := r.resolveNameservers(ctx, nsRecords, merged.Additional) 781 | if len(nextNS) == 0 { 782 | return merged, nil 783 | } 784 | 785 | return r.resolveRecursiveAll(ctx, domain, qtype, nextNS, depth+1) 786 | } 787 | 788 | return merged, nil 789 | } 790 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------