feat: ndots and search list support

TODO.md

@@ -5,26 +5,26 @@
 - [x]] Add methods to initialise the config, set defaults
 - [x] Add a resolve method
 - [x] Make it separate from Hub
-- [ ] Parse output into separate fields
-- [ ] Test UDP6
+- [x] Parse output into separate fields
+- [ ] Test IPv6
 - [x] Add DOH support
 - [x] Add DOT support
 - [x] Add DNS protocol on TCP mode support.
 
 ## CLI Features
 - [ ] `digfile`
-- [ ] `ndots` support
-- [ ] `search path` support
-- [ ] JSON output
-- [ ] Colorized output
-- [ ] Table output
+- [x] `ndots` support
+- [x] `search path` support
+- [x] JSON output
+- [x] Colorized output
+- [x] Table output
 
 ## CLI Grunt
 - [x] Query args
 - [x] Neatly package them to load args in different functions
 - [x] Upper case is not mandatory for query type/classes
-- [ ] Output
-- [ ] Add client transport options
+- [x] Output
+- [x] Add client transport options
 
 ## Tests
 

cmd/cli.go

@@ -8,14 +8,13 @@ import (
 
 var (
 	// Version and date of the build. This is injected at build-time.
-	buildVersion   = "unknown"
-	buildDate      = "unknown"
-	verboseEnabled = false
+	buildVersion = "unknown"
+	buildDate    = "unknown"
 )
 
 func main() {
 	var (
-		logger = initLogger(verboseEnabled)
+		logger = initLogger()
 		app    = cli.NewApp()
 	)
 	// Initialize hub.
@@ -88,6 +87,17 @@ func main() {
 			Usage:       "Display how long it took for the response to arrive",
 			Destination: &hub.QueryFlags.DisplayTimeTaken,
 		},
+		&cli.BoolFlag{
+			Name:        "search",
+			Usage:       "Use the search list provided in resolv.conf. It sets the `ndots` parameter as well unless overriden by `ndots` flag.",
+			Destination: &hub.QueryFlags.UseSearchList,
+		},
+		&cli.IntFlag{
+			Name:        "ndots",
+			Usage:       "Specify the ndots paramter",
+			DefaultText: "Default value is that set in `/etc/resolv.conf` or 1 if no `ndots` statement is present.",
+			Destination: &hub.QueryFlags.Ndots,
+		},
 		&cli.BoolFlag{
 			Name:        "json",
 			Aliases:     []string{"J"},
@@ -95,13 +105,12 @@ func main() {
 			Destination: &hub.QueryFlags.ShowJSON,
 		},
 		&cli.BoolFlag{
-			Name:        "verbose",
+			Name:        "debug",
 			Usage:       "Enable verbose logging",
-			Destination: &verboseEnabled,
+			Destination: &hub.QueryFlags.Verbose,
 			DefaultText: "false",
 		},
 	}
-
 	app.Before = hub.loadQueryArgs
 	app.Action = func(c *cli.Context) error {
 		if len(hub.QueryFlags.QNames.Value()) == 0 {
@@ -110,6 +119,7 @@ func main() {
 		hub.Lookup(c)
 		return nil
 	}
+
 	// Run the app.
 	hub.Logger.Debug("Starting doggo...")
 	err := app.Run(os.Args)

cmd/hub.go

@@ -14,6 +14,7 @@ type Hub struct {
 	QueryFlags QueryFlags
 	Questions  []dns.Question
 	Resolver   resolvers.Resolver
+	cliContext *cli.Context
 }
 
 // QueryFlags is used store the value of CLI flags.
@@ -30,6 +31,9 @@ type QueryFlags struct {
 	UseIPv6          bool
 	DisplayTimeTaken bool
 	ShowJSON         bool
+	Verbose          bool
+	UseSearchList    bool
+	Ndots            int
 }
 
 // NewHub initializes an instance of Hub which holds app wide configuration.
@@ -49,18 +53,11 @@ func NewHub(logger *logrus.Logger, buildVersion string) *Hub {
 }
 
 // initLogger initializes logger
-func initLogger(verbose bool) *logrus.Logger {
+func initLogger() *logrus.Logger {
 	logger := logrus.New()
 	logger.SetFormatter(&logrus.TextFormatter{
 		DisableTimestamp:       true,
 		DisableLevelTruncation: true,
 	})
-	// Set logger level
-	if verbose {
-		logger.SetLevel(logrus.DebugLevel)
-		logger.Debug("verbose logging enabled")
-	} else {
-		logger.SetLevel(logrus.InfoLevel)
-	}
 	return logger
 }

cmd/lookup.go

@@ -4,12 +4,17 @@ import (
 	"strings"
 
 	"github.com/miekg/dns"
+	"github.com/mr-karan/doggo/pkg/resolvers"
+	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
 
 // Lookup sends the DNS queries to the server.
 func (hub *Hub) Lookup(c *cli.Context) error {
-	hub.prepareQuestions()
+	err := hub.prepareQuestions()
+	if err != nil {
+		return err
+	}
 	responses, err := hub.Resolver.Lookup(hub.Questions)
 	if err != nil {
 		return err
@@ -21,19 +26,57 @@ func (hub *Hub) Lookup(c *cli.Context) error {
 // prepareQuestions iterates on list of domain names
 // and prepare a list of questions
 // sent to the server with all possible combinations.
-func (hub *Hub) prepareQuestions() {
-	var question dns.Question
+func (hub *Hub) prepareQuestions() error {
+	var (
+		question dns.Question
+	)
 	for _, name := range hub.QueryFlags.QNames.Value() {
-		question.Name = dns.Fqdn(name)
-		// iterate on a list of query types.
-		for _, q := range hub.QueryFlags.QTypes.Value() {
-			question.Qtype = dns.StringToType[strings.ToUpper(q)]
-			// iterate on a list of query classes.
-			for _, c := range hub.QueryFlags.QClasses.Value() {
-				question.Qclass = dns.StringToClass[strings.ToUpper(c)]
-				// append a new question for each possible pair.
-				hub.Questions = append(hub.Questions, question)
+		var (
+			domains []string
+			ndots   int
+		)
+
+		// If `search` flag is specified then fetch the search list
+		// from `resolv.conf` and set the
+		if hub.QueryFlags.UseSearchList {
+			list, n, err := fetchDomainList(name, hub.cliContext.IsSet("ndots"), hub.QueryFlags.Ndots)
+			if err != nil {
+				return err
+			}
+			domains = list
+			ndots = n
+		} else {
+			domains = []string{dns.Fqdn(name)}
+		}
+		for _, d := range domains {
+			hub.Logger.WithFields(logrus.Fields{
+				"domain": d,
+				"ndots":  ndots,
+			}).Debug("Attmepting to resolve")
+			question.Name = d
+			// iterate on a list of query types.
+			for _, q := range hub.QueryFlags.QTypes.Value() {
+				question.Qtype = dns.StringToType[strings.ToUpper(q)]
+				// iterate on a list of query classes.
+				for _, c := range hub.QueryFlags.QClasses.Value() {
+					question.Qclass = dns.StringToClass[strings.ToUpper(c)]
+					// append a new question for each possible pair.
+					hub.Questions = append(hub.Questions, question)
+				}
 			}
 		}
 	}
+	return nil
+}
+
+func fetchDomainList(d string, isNdotsSet bool, ndots int) ([]string, int, error) {
+	cfg, err := dns.ClientConfigFromFile(resolvers.DefaultResolvConfPath)
+	if err != nil {
+		return nil, 0, err
+	}
+	// if user specified a custom ndots parameter, override it
+	if isNdotsSet {
+		cfg.Ndots = ndots
+	}
+	return cfg.NameList(d), cfg.Ndots, nil
 }

cmd/output.go

@@ -14,12 +14,13 @@ import (
 
 // Output has a list of fields which are produced for the output
 type Output struct {
-	Name      string `json:"name"`
-	Type      string `json:"type"`
-	Class     string `json:"class"`
-	TTL       string `json:"ttl"`
-	Address   string `json:"address"`
-	TimeTaken string `json:"rtt"`
+	Name       string `json:"name"`
+	Type       string `json:"type"`
+	Class      string `json:"class"`
+	TTL        string `json:"ttl"`
+	Address    string `json:"address"`
+	TimeTaken  string `json:"rtt"`
+	Nameserver string `json:"nameserver"`
 }
 
 type Query struct {
@@ -113,12 +114,13 @@ func collectOutput(responses []resolvers.Response) []Output {
 			qtype := dns.Type(h.Rrtype).String()
 			rtt := fmt.Sprintf("%dms", r.RTT.Milliseconds())
 			o := Output{
-				Name:      name,
-				Type:      qtype,
-				TTL:       ttl,
-				Class:     qclass,
-				Address:   addr,
-				TimeTaken: rtt,
+				Name:       name,
+				Type:       qtype,
+				TTL:        ttl,
+				Class:      qclass,
+				Address:    addr,
+				TimeTaken:  rtt,
+				Nameserver: r.Nameserver,
 			}
 			out = append(out, o)
 		}

cmd/parse.go

@@ -4,10 +4,20 @@ import (
 	"strings"
 
 	"github.com/miekg/dns"
+	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
 
 func (hub *Hub) loadQueryArgs(c *cli.Context) error {
+	// set log level
+	if c.Bool("debug") {
+		// Set logger level
+		hub.Logger.SetLevel(logrus.DebugLevel)
+	} else {
+		hub.Logger.SetLevel(logrus.InfoLevel)
+	}
+	hub.cliContext = c
+
 	err := hub.loadFreeArgs(c)
 	if err != nil {
 		cli.Exit("Error parsing arguments", -1)

cmd/resolver.go

@@ -23,7 +23,7 @@ func (hub *Hub) initResolver(c *cli.Context) error {
 		if runtime.GOOS == "windows" {
 			// TODO: Add a method for reading system default nameserver in windows.
 		} else {
-			rslvr, err := resolvers.NewResolverFromResolvFile(resolvers.DefaultResolvConfPath)
+			rslvr, err := resolvers.NewSystemResolver(resolvers.DefaultResolvConfPath)
 			if err != nil {
 				return err
 			}

pkg/resolvers/classic.go

@@ -1,7 +1,6 @@
 package resolvers
 
 import (
-	"fmt"
 	"net"
 
 	"github.com/miekg/dns"
@@ -47,6 +46,7 @@ func NewClassicResolver(servers []string, opts ClassicResolverOpts) (Resolver, e
 			nameservers = append(nameservers, srv)
 		}
 	}
+
 	client.Net = "udp"
 	if opts.UseIPv4 {
 		client.Net = "udp4"
@@ -66,35 +66,6 @@ func NewClassicResolver(servers []string, opts ClassicResolverOpts) (Resolver, e
 	}, nil
 }
 
-// NewResolverFromResolvFile loads the configuration from resolv config file
-// and initialises a DNS resolver.
-func NewResolverFromResolvFile(resolvFilePath string) (Resolver, error) {
-	if resolvFilePath == "" {
-		resolvFilePath = DefaultResolvConfPath
-	}
-	cfg, err := dns.ClientConfigFromFile(resolvFilePath)
-	if err != nil {
-		return nil, err
-	}
-
-	servers := make([]string, 0, len(cfg.Servers))
-	for _, s := range cfg.Servers {
-		ip := net.ParseIP(s)
-		// handle IPv6
-		if ip != nil && ip.To4() != nil {
-			servers = append(servers, fmt.Sprintf("%s:%s", s, cfg.Port))
-		} else {
-			servers = append(servers, fmt.Sprintf("[%s]:%s", s, cfg.Port))
-		}
-	}
-
-	client := &dns.Client{}
-	return &ClassicResolver{
-		client:  client,
-		servers: servers,
-	}, nil
-}
-
 // Lookup prepare a list of DNS messages to be sent to the server.
 // It's possible to send multiple question in one message
 // but some nameservers are not able to

pkg/resolvers/doh.go

@@ -26,7 +26,7 @@ func NewDOHResolver(servers []string) (Resolver, error) {
 	}, nil
 }
 
-func (r *DOHResolver) Lookup(questions []dns.Question) ([]Response, error) {
+func (d *DOHResolver) Lookup(questions []dns.Question) ([]Response, error) {
 	var (
 		messages  = prepareMessages(questions)
 		responses []Response
@@ -38,10 +38,10 @@ func (r *DOHResolver) Lookup(questions []dns.Question) ([]Response, error) {
 		if err != nil {
 			return nil, err
 		}
-		for _, srv := range r.servers {
+		for _, srv := range d.servers {
 			now := time.Now()
 			// Make an HTTP POST request to the DNS server with the DNS message as wire format bytes in the body.
-			resp, err := r.client.Post(srv, "application/dns-message", bytes.NewBuffer(b))
+			resp, err := d.client.Post(srv, "application/dns-message", bytes.NewBuffer(b))
 			if err != nil {
 				return nil, err
 			}

pkg/resolvers/system.go

@@ -0,0 +1,84 @@
+package resolvers
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/miekg/dns"
+)
+
+// SystemResolver represents the config options based on the
+// resolvconf file.
+type SystemResolver struct {
+	client  *dns.Client
+	config  *dns.ClientConfig
+	servers []string
+}
+
+// NewSystemResolver loads the configuration from resolv config file
+// and initialises a DNS resolver.
+func NewSystemResolver(resolvFilePath string) (Resolver, error) {
+	if resolvFilePath == "" {
+		resolvFilePath = DefaultResolvConfPath
+	}
+	cfg, err := dns.ClientConfigFromFile(resolvFilePath)
+	if err != nil {
+		return nil, err
+	}
+
+	servers := make([]string, 0, len(cfg.Servers))
+	for _, s := range cfg.Servers {
+		ip := net.ParseIP(s)
+		// handle IPv6
+		if ip != nil && ip.To4() != nil {
+			servers = append(servers, fmt.Sprintf("%s:%s", s, cfg.Port))
+		} else {
+			servers = append(servers, fmt.Sprintf("[%s]:%s", s, cfg.Port))
+		}
+	}
+
+	client := &dns.Client{}
+	return &SystemResolver{
+		client:  client,
+		servers: servers,
+		config:  cfg,
+	}, nil
+}
+
+// Lookup prepare a list of DNS messages to be sent to the server.
+// It's possible to send multiple question in one message
+// but some nameservers are not able to
+func (s *SystemResolver) Lookup(questions []dns.Question) ([]Response, error) {
+	for _, q := range questions {
+		domains := s.config.NameList(q.Name)
+		for _, d := range domains {
+			ques := dns.Question{
+				Name:   d,
+				Qtype:  q.Qtype,
+				Qclass: q.Qclass,
+			}
+			questions = append(questions, ques)
+		}
+	}
+	var (
+		messages  = prepareMessages(questions)
+		responses []Response
+	)
+
+	for _, msg := range messages {
+		for _, srv := range s.servers {
+			in, rtt, err := s.client.Exchange(&msg, srv)
+			if err != nil {
+				return nil, err
+			}
+			msg.Answer = in.Answer
+			rsp := Response{
+				Message:    msg,
+				RTT:        rtt,
+				Nameserver: srv,
+			}
+			responses = append(responses, rsp)
+		}
+	}
+	return responses, nil
+}