package dns import ( "fmt" "github.com/google/gopacket/layers" "golang.org/x/net/publicsuffix" "log" ) var ( numAnswers int answerDomains []string answerBaseDomains []string answerPrivateDomains []string answerType = make(map[layers.DNSType]int) answerPublicIPv4 []string answerPrivateIPv4 []string ) // Called on every DNS packet to process response(s) func processDNSAnswer(answers []layers.DNSResourceRecord) { for _, answer := range answers { // Raise stats numAnswers++ // Add answer to answers array name := string(answer.Name) basename, basenameErr := publicsuffix.EffectiveTLDPlusOne(name) if basenameErr != nil { // Encountered error while checking for the basename log.Printf("Encountered error while checking '%s' domain for its basename: %s", name, basenameErr.Error()) continue } // Process type answers processType(answerType, answer.Type) // Append full domain and base domain answerDomains = appendIfUnique(name, answerDomains) // Check if we need to add the base name to the private list _, icannManaged := publicsuffix.PublicSuffix(name) if icannManaged { // TLD is managed by ICANN, add to the base list answerBaseDomains = appendIfUnique(basename, answerBaseDomains) } else { // it's not managed by ICANN, so it's private - add it to the private list answerPrivateDomains = appendIfUnique(name, answerPrivateDomains) } // Check if we got an A record answer if answer.Type == layers.DNSTypeA { // A record, check IP for being private if ipIsPrivate(answer.IP) { answerPrivateIPv4 = append(answerPrivateIPv4, answer.IP.String()) } else { answerPublicIPv4 = append(answerPublicIPv4, answer.IP.String()) } } } } // Prints a summary of all DNS answers func printDNSAnswerSummary() { // Overall question stats fmt.Printf("%d DNS answers in total\n", numAnswers) fmt.Printf("%s records\n", generateDNSTypeSummary(answerType)) fmt.Printf("%d unique domains of %d base domains, of which are %d private (non-ICANN) TLDs.\n", len(answerDomains), len(answerBaseDomains), len(answerPrivateDomains)) // Output base domains answered with if len(answerBaseDomains) > 0 { fmt.Println("Answered with these base domains:") printTree(answerBaseDomains) } // Output private domains if len(answerPrivateDomains) > 0 { fmt.Println("Answered with these private (non-ICANN managed) domains:") printTree(answerPrivateDomains) } // Check for public and private IPs fmt.Printf("Answered with %d public IP addresses and %d private IP addresses\n", len(answerPublicIPv4), len(answerPrivateIPv4)) if len(answerPrivateIPv4) > 0 { fmt.Println("Private IP addresses in answer:") printTree(answerPrivateIPv4) } }