feat: add tls config for dot lookups

Ref https://github.com/mr-karan/doggo/issues/29

README.md

@@ -216,6 +216,8 @@ URL scheme of the server is used to identify which resolver to use for lookups.
   --timeout                     Specify timeout (in seconds) for the resolver to return a response.
   -4 --ipv4                     Use IPv4 only.
   -6 --ipv6                     Use IPv6 only.
+  --tls-hostname=HOSTNAME       Provide a hostname for doing verification of the certificate if the provided DoT nameserver is an IP.
+  --skip-hostname-verification  Skip TLS Hostname Verification in case of DOT Lookups.
 ```
 
 

cmd/doggo/cli.go

@@ -46,6 +46,8 @@ func main() {
 	f.BoolP("ipv4", "4", false, "Use IPv4 only")
 	f.BoolP("ipv6", "6", false, "Use IPv6 only")
 	f.String("strategy", "all", "Strategy to query nameservers in resolv.conf file (`all`, `random`, `first`)")
+	f.String("tls-hostname", "", "Provide a hostname for doing verification of the certificate if the provided DoT nameserver is an IP")
+	f.Bool("skip-hostname-verification", false, "Skip TLS Hostname Verification")
 
 	// Output Options
 	f.BoolP("json", "J", false, "Set the output format as JSON")
@@ -129,6 +131,8 @@ func main() {
 		Timeout:            app.QueryFlags.Timeout * time.Second,
 		Logger:             app.Logger,
 		Strategy:           app.QueryFlags.Strategy,
+		InsecureSkipVerify: app.QueryFlags.InsecureSkipVerify,
+		TLSHostname:        app.QueryFlags.TLSHostname,
 	})
 	if err != nil {
 		app.Logger.WithError(err).Error("error loading resolver")

cmd/doggo/help.go

@@ -53,6 +53,9 @@ var appHelpTextTemplate = `{{ "NAME" | color "" "heading" }}:
   {{"--timeout" | color "yellow" ""}}                    Specify timeout (in seconds) for the resolver to return a response.
   {{"-4 --ipv4" | color "yellow" ""}}                    Use IPv4 only.
   {{"-6 --ipv6" | color "yellow" ""}}                    Use IPv6 only.
+  {{"--ndots=INT" | color "yellow" ""}}                  Specify ndots parameter. Takes value from /etc/resolv.conf if using the system namesever or 1 otherwise.
+  {{"--tls-hostname=HOSTNAME" | color "yellow" ""}}      Provide a hostname for doing verification of the certificate if the provided DoT nameserver is an IP.
+  {{"--skip-hostname-verification" | color "yellow" ""}} Skip TLS Hostname Verification in case of DOT Lookups.
 
 {{ "Output Options" | color "" "heading" }}:
   {{"-J, --json " | color "yellow" ""}}                 Format the output as JSON.

pkg/models/models.go

@@ -37,6 +37,8 @@ type QueryFlags struct {
 	UseSearchList      bool          `koanf:"search" json:"-"`
 	ReverseLookup      bool          `koanf:"reverse" reverse:"-"`
 	Strategy           string        `koanf:"strategy" strategy:"-"`
+	InsecureSkipVerify bool          `koanf:"skip-hostname-verification" skip-hostname-verification:"-"`
+	TLSHostname        string        `koanf:"tls-hostname" tls-hostname:"-"`
 }
 
 // Nameserver represents the type of Nameserver

pkg/resolvers/classic.go

@@ -1,6 +1,7 @@
 package resolvers
 
 import (
+	"crypto/tls"
 	"time"
 
 	"github.com/miekg/dns"
@@ -16,8 +17,6 @@ type ClassicResolver struct {
 
 // ClassicResolverOpts holds options for setting up a Classic resolver.
 type ClassicResolverOpts struct {
-	IPv4Only bool
-	IPv6Only bool
 	UseTLS bool
 	UseTCP bool
 }
@@ -34,15 +33,20 @@ func NewClassicResolver(server string, classicOpts ClassicResolverOpts, resolver
 		net = "tcp"
 	}
 
-	if classicOpts.IPv4Only {
+	if resolverOpts.UseIPv4 {
 		net = net + "4"
 	}
-	if classicOpts.IPv6Only {
+	if resolverOpts.UseIPv6 {
 		net = net + "6"
 	}
 
 	if classicOpts.UseTLS {
 		net = net + "-tls"
+		// Provide extra TLS config for doing/skipping hostname verification.
+		client.TLSConfig = &tls.Config{
+			ServerName:         resolverOpts.TLSHostname,
+			InsecureSkipVerify: resolverOpts.InsecureSkipVerify,
+		}
 	}
 
 	client.Net = net

pkg/resolvers/dnscrypt.go

@@ -18,9 +18,6 @@ type DNSCryptResolver struct {
 
 // DNSCryptResolverOpts holds options for setting up a DNSCrypt resolver.
 type DNSCryptResolverOpts struct {
-	IPv4Only bool
-	IPv6Only bool
-	UseTLS   bool
 	UseTCP bool
 }
 
@@ -30,6 +27,7 @@ func NewDNSCryptResolver(server string, dnscryptOpts DNSCryptResolverOpts, resol
 	if dnscryptOpts.UseTCP {
 		net = "tcp"
 	}
+
 	client := &dnscrypt.Client{Net: net, Timeout: resolverOpts.Timeout, UDPSize: 4096}
 	resolverInfo, err := client.Dial(server)
 	if err != nil {

pkg/resolvers/resolver.go

@@ -11,14 +11,17 @@ import (
 // Options represent a set of common options
 // to configure a Resolver.
 type Options struct {
+	Logger *logrus.Logger
+
 	Nameservers        []models.Nameserver
 	UseIPv4            bool
 	UseIPv6            bool
 	SearchList         []string
 	Ndots              int
 	Timeout            time.Duration
-	Logger      *logrus.Logger
 	Strategy           string
+	InsecureSkipVerify bool
+	TLSHostname        string
 }
 
 // Resolver implements the configuration for a DNS
@@ -68,18 +71,13 @@ type Authority struct {
 // LoadResolvers loads differently configured
 // resolvers based on a list of nameserver.
 func LoadResolvers(opts Options) ([]Resolver, error) {
-	var resolverOpts = Options{
+	// For each nameserver, initialise the correct resolver.
-		Timeout:    opts.Timeout,
-		Ndots:      opts.Ndots,
-		SearchList: opts.SearchList,
-		Logger:     opts.Logger,
-	}
-	// for each nameserver, initialise the correct resolver
 	rslvrs := make([]Resolver, 0, len(opts.Nameservers))
+
 	for _, ns := range opts.Nameservers {
 		if ns.Type == models.DOHResolver {
 			opts.Logger.Debug("initiating DOH resolver")
-			rslvr, err := NewDOHResolver(ns.Address, resolverOpts)
+			rslvr, err := NewDOHResolver(ns.Address, opts)
 			if err != nil {
 				return rslvrs, err
 			}
@@ -89,11 +87,9 @@ func LoadResolvers(opts Options) ([]Resolver, error) {
 			opts.Logger.Debug("initiating DOT resolver")
 			rslvr, err := NewClassicResolver(ns.Address,
 				ClassicResolverOpts{
-					IPv4Only: opts.UseIPv4,
-					IPv6Only: opts.UseIPv6,
 					UseTLS: true,
 					UseTCP: true,
-				}, resolverOpts)
+				}, opts)
 
 			if err != nil {
 				return rslvrs, err
@@ -104,11 +100,9 @@ func LoadResolvers(opts Options) ([]Resolver, error) {
 			opts.Logger.Debug("initiating TCP resolver")
 			rslvr, err := NewClassicResolver(ns.Address,
 				ClassicResolverOpts{
-					IPv4Only: opts.UseIPv4,
-					IPv6Only: opts.UseIPv6,
 					UseTLS: false,
 					UseTCP: true,
-				}, resolverOpts)
+				}, opts)
 			if err != nil {
 				return rslvrs, err
 			}
@@ -118,11 +112,9 @@ func LoadResolvers(opts Options) ([]Resolver, error) {
 			opts.Logger.Debug("initiating UDP resolver")
 			rslvr, err := NewClassicResolver(ns.Address,
 				ClassicResolverOpts{
-					IPv4Only: opts.UseIPv4,
-					IPv6Only: opts.UseIPv6,
 					UseTLS: false,
 					UseTCP: false,
-				}, resolverOpts)
+				}, opts)
 			if err != nil {
 				return rslvrs, err
 			}
@@ -133,7 +125,7 @@ func LoadResolvers(opts Options) ([]Resolver, error) {
 			rslvr, err := NewDNSCryptResolver(ns.Address,
 				DNSCryptResolverOpts{
 					UseTCP: false,
-				}, resolverOpts)
+				}, opts)
 			if err != nil {
 				return rslvrs, err
 			}
@@ -141,7 +133,7 @@ func LoadResolvers(opts Options) ([]Resolver, error) {
 		}
 		if ns.Type == models.DOQResolver {
 			opts.Logger.Debug("initiating DOQ resolver")
-			rslvr, err := NewDOQResolver(ns.Address, resolverOpts)
+			rslvr, err := NewDOQResolver(ns.Address, opts)
 			if err != nil {
 				return rslvrs, err
 			}