From fa1b8aa148c55c065c99071fc8a9fc5e36bd373e Mon Sep 17 00:00:00 2001
From: Daniel <dhaavi@users.noreply.github.com>
Date: Mon, 25 Jan 2021 17:11:48 +0100
Subject: [PATCH] Improve resolver API

---
 resolver/api.go      | 49 ++++++++++++++++++++++++++++++++++++++++++++
 resolver/main.go     | 15 ++++----------
 resolver/resolver.go |  8 ++++----
 resolver/scopes.go   |  4 ----
 4 files changed, 57 insertions(+), 19 deletions(-)
 create mode 100644 resolver/api.go

diff --git a/resolver/api.go b/resolver/api.go
new file mode 100644
index 00000000..69700c48
--- /dev/null
+++ b/resolver/api.go
@@ -0,0 +1,49 @@
+package resolver
+
+import (
+	"github.com/safing/portbase/api"
+)
+
+func registerAPI() error {
+	if err := api.RegisterEndpoint(api.Endpoint{
+		Path:        "dns/clear",
+		Read:        api.PermitUser,
+		ActionFunc:  clearNameCache,
+		Name:        "Clear cached DNS records",
+		Description: "Deletes all saved DNS records from the database.",
+	}); err != nil {
+		return err
+	}
+
+	if err := api.RegisterEndpoint(api.Endpoint{
+		Path:        "dns/resolvers",
+		Read:        api.PermitAnyone,
+		StructFunc:  exportDNSResolvers,
+		Name:        "List DNS Resolvers",
+		Description: "List currently configured DNS resolvers and their status.",
+	}); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type resolverExport struct {
+	*Resolver
+	Failing bool
+}
+
+func exportDNSResolvers(*api.Request) (interface{}, error) {
+	resolversLock.RLock()
+	defer resolversLock.RUnlock()
+
+	export := make([]*resolverExport, 0, len(globalResolvers))
+	for _, r := range globalResolvers {
+		export = append(export, &resolverExport{
+			Resolver: r,
+			Failing:  r.Conn.IsFailing(),
+		})
+	}
+
+	return export, nil
+}
diff --git a/resolver/main.go b/resolver/main.go
index 343d5a50..bb1825c6 100644
--- a/resolver/main.go
+++ b/resolver/main.go
@@ -6,8 +6,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/safing/portbase/api"
-
 	"github.com/safing/portbase/log"
 	"github.com/safing/portbase/modules"
 	"github.com/safing/portmaster/intel"
@@ -31,6 +29,10 @@ func init() {
 func prep() error {
 	intel.SetReverseResolver(ResolveIPAndValidate)
 
+	if err := registerAPI(); err != nil {
+		return err
+	}
+
 	if err := prepEnvResolver(); err != nil {
 		return err
 	}
@@ -78,15 +80,6 @@ func start() error {
 		return err
 	}
 
-	// Register api endpoint to clear DNS cache.
-	if err := api.RegisterEndpoint(api.Endpoint{
-		Path:       "dns/clear/namecache",
-		Read:       api.PermitUser,
-		ActionFunc: clearNameCache,
-	}); err != nil {
-		return err
-	}
-
 	// DEPRECATED: remove in v0.7
 	// cache clearing
 	err = module.RegisterEventHook(
diff --git a/resolver/resolver.go b/resolver/resolver.go
index d7f21555..ad7f5741 100644
--- a/resolver/resolver.go
+++ b/resolver/resolver.go
@@ -41,6 +41,9 @@ type Resolver struct {
 	//	- `zeroip`: Answer only contains zeroip
 	Server string
 
+	// Source describes from where the resolver configuration originated.
+	Source string
+
 	// Name is the name of the resolver as passed via
 	// ?name=.
 	Name string
@@ -65,12 +68,9 @@ type Resolver struct {
 	// Special Options
 	VerifyDomain string
 	Search       []string
-	SkipFQDN     string
-
-	Source string
 
 	// logic interface
-	Conn ResolverConn
+	Conn ResolverConn `json:"-"`
 }
 
 // IsBlockedUpstream returns true if the request has been blocked
diff --git a/resolver/scopes.go b/resolver/scopes.go
index 0943cf2b..f0102b17 100644
--- a/resolver/scopes.go
+++ b/resolver/scopes.go
@@ -208,10 +208,6 @@ func (q *Query) checkCompliance() error {
 }
 
 func (resolver *Resolver) checkCompliance(_ context.Context, q *Query) error {
-	if q.FQDN == resolver.SkipFQDN {
-		return errSkip
-	}
-
 	if noInsecureProtocols(q.SecurityLevel) {
 		switch resolver.ServerType {
 		case ServerTypeDNS: