wip: migrate to mono-repo. SPN has already been moved to spn/

service/intel/block_reason.go

@@ -0,0 +1,103 @@
+package intel
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/miekg/dns"
+
+	"github.com/safing/portbase/log"
+	"github.com/safing/portmaster/service/nameserver/nsutil"
+)
+
+// ListMatch represents an entity that has been
+// matched against filterlists.
+type ListMatch struct {
+	Entity        string
+	ActiveLists   []string
+	InactiveLists []string
+}
+
+func (lm *ListMatch) String() string {
+	inactive := ""
+	if len(lm.InactiveLists) > 0 {
+		inactive = " and in deactivated lists " + strings.Join(lm.InactiveLists, ", ")
+	}
+	return fmt.Sprintf(
+		"%s in activated lists %s%s",
+		lm.Entity,
+		strings.Join(lm.ActiveLists, ","),
+		inactive,
+	)
+}
+
+// ListBlockReason is a list of list matches.
+type ListBlockReason []ListMatch
+
+func (br ListBlockReason) String() string {
+	if len(br) == 0 {
+		return ""
+	}
+
+	matches := make([]string, len(br))
+	for idx, lm := range br {
+		matches[idx] = lm.String()
+	}
+
+	return strings.Join(matches, " and ")
+}
+
+// Context returns br wrapped into a map. It implements
+// the endpoints.Reason interface.
+func (br ListBlockReason) Context() interface{} {
+	return br
+}
+
+// MarshalJSON marshals the list block reason into a map
+// prefixed with filterlists.
+func (br ListBlockReason) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]interface{}{
+		// we convert to []ListMatch to avoid recursing
+		// here.
+		"filterlists": []ListMatch(br),
+	})
+}
+
+// GetExtraRRs implements the nsutil.RRProvider interface
+// and adds additional TXT records justifying the reason
+// the request was blocked.
+func (br ListBlockReason) GetExtraRRs(ctx context.Context, _ *dns.Msg) []dns.RR {
+	rrs := make([]dns.RR, 0, len(br))
+
+	for _, lm := range br {
+		blockedBy, err := nsutil.MakeMessageRecord(log.InfoLevel, fmt.Sprintf(
+			"%s is blocked by filter lists %s",
+			lm.Entity,
+			strings.Join(lm.ActiveLists, ", "),
+		))
+		if err == nil {
+			rrs = append(rrs, blockedBy)
+		} else {
+			log.Tracer(ctx).Errorf("intel: failed to create TXT RR for block reason: %s", err)
+		}
+
+		if len(lm.InactiveLists) > 0 {
+			wouldBeBlockedBy, err := nsutil.MakeMessageRecord(log.InfoLevel, fmt.Sprintf(
+				"%s would be blocked by filter lists %s",
+				lm.Entity,
+				strings.Join(lm.InactiveLists, ", "),
+			))
+			if err == nil {
+				rrs = append(rrs, wouldBeBlockedBy)
+			} else {
+				log.Tracer(ctx).Errorf("intel: failed to create TXT RR for block reason: %s", err)
+			}
+		}
+	}
+
+	return rrs
+}
+
+var _ nsutil.RRProvider = ListBlockReason(nil)