Initial commit after restructure

intel/dns.go

@@ -0,0 +1,218 @@
+// Copyright Safing ICS Technologies GmbH. Use of this source code is governed by the AGPL license that can be found in the LICENSE file.
+
+package intel
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/Safing/safing-core/database"
+
+	datastore "github.com/ipfs/go-datastore"
+	"github.com/miekg/dns"
+)
+
+// RRCache is used to cache DNS data
+type RRCache struct {
+	Answer          []dns.RR
+	Ns              []dns.RR
+	Extra           []dns.RR
+	Expires         int64
+	Modified        int64
+	servedFromCache bool
+	requestingNew   bool
+}
+
+func (m *RRCache) Clean(minExpires uint32) {
+
+	var lowestTTL uint32 = 0xFFFFFFFF
+	var header *dns.RR_Header
+
+	// set TTLs to 17
+	// TODO: double append? is there something more elegant?
+	for _, rr := range append(m.Answer, append(m.Ns, m.Extra...)...) {
+		header = rr.Header()
+		if lowestTTL > header.Ttl {
+			lowestTTL = header.Ttl
+		}
+		header.Ttl = 17
+	}
+
+	// TTL must be at least minExpires
+	if lowestTTL < minExpires {
+		lowestTTL = minExpires
+	}
+
+	m.Expires = time.Now().Unix() + int64(lowestTTL)
+	m.Modified = time.Now().Unix()
+
+}
+
+func (m *RRCache) ExportAllARecords() (ips []net.IP) {
+	for _, rr := range m.Answer {
+		if rr.Header().Class == dns.ClassINET && rr.Header().Rrtype == dns.TypeA {
+			aRecord, ok := rr.(*dns.A)
+			if ok {
+				ips = append(ips, aRecord.A)
+			}
+		} else if rr.Header().Class == dns.ClassINET && rr.Header().Rrtype == dns.TypeAAAA {
+			aRecord, ok := rr.(*dns.AAAA)
+			if ok {
+				ips = append(ips, aRecord.AAAA)
+			}
+		}
+	}
+	return
+}
+
+func (m *RRCache) ToRRSave() *RRSave {
+	var s RRSave
+	s.Expires = m.Expires
+	s.Modified = m.Modified
+	for _, entry := range m.Answer {
+		s.Answer = append(s.Answer, entry.String())
+	}
+	for _, entry := range m.Ns {
+		s.Ns = append(s.Ns, entry.String())
+	}
+	for _, entry := range m.Extra {
+		s.Extra = append(s.Extra, entry.String())
+	}
+	return &s
+}
+
+func (m *RRCache) Create(name string) error {
+	s := m.ToRRSave()
+	return s.CreateObject(&database.DNSCache, name, s)
+}
+
+func (m *RRCache) CreateWithType(name string, qtype dns.Type) error {
+	s := m.ToRRSave()
+	return s.Create(fmt.Sprintf("%s%s", name, qtype.String()))
+}
+
+func (m *RRCache) Save() error {
+	s := m.ToRRSave()
+	return s.SaveObject(s)
+}
+
+func GetRRCache(domain string, qtype dns.Type) (*RRCache, error) {
+	return GetRRCacheFromNamespace(&database.DNSCache, domain, qtype)
+}
+
+func GetRRCacheFromNamespace(namespace *datastore.Key, domain string, qtype dns.Type) (*RRCache, error) {
+	var m RRCache
+
+	rrSave, err := GetRRSaveFromNamespace(namespace, domain, qtype)
+	if err != nil {
+		return nil, err
+	}
+
+	m.Expires = rrSave.Expires
+	m.Modified = rrSave.Modified
+	for _, entry := range rrSave.Answer {
+		rr, err := dns.NewRR(entry)
+		if err == nil {
+			m.Answer = append(m.Answer, rr)
+		}
+	}
+	for _, entry := range rrSave.Ns {
+		rr, err := dns.NewRR(entry)
+		if err == nil {
+			m.Ns = append(m.Ns, rr)
+		}
+	}
+	for _, entry := range rrSave.Extra {
+		rr, err := dns.NewRR(entry)
+		if err == nil {
+			m.Extra = append(m.Extra, rr)
+		}
+	}
+
+	m.servedFromCache = true
+	return &m, nil
+}
+
+// ServedFromCache marks the RRCache as served from cache.
+func (m *RRCache) ServedFromCache() bool {
+	return m.servedFromCache
+}
+
+// RequestingNew informs that it has expired and new RRs are being fetched.
+func (m *RRCache) RequestingNew() bool {
+	return m.requestingNew
+}
+
+// Flags formats ServedFromCache and RequestingNew to a condensed, flag-like format.
+func (m *RRCache) Flags() string {
+	switch {
+	case m.servedFromCache && m.requestingNew:
+		return " [CR]"
+	case m.servedFromCache:
+		return " [C]"
+	case m.requestingNew:
+		return " [R]" // theoretically impossible, but let's leave it here, just in case
+	default:
+		return ""
+	}
+}
+
+// IsNXDomain returnes whether the result is nxdomain.
+func (m *RRCache) IsNXDomain() bool {
+	return len(m.Answer) == 0
+}
+
+// RRSave is helper struct to RRCache to better save data to the database.
+type RRSave struct {
+	database.Base
+	Answer   []string
+	Ns       []string
+	Extra    []string
+	Expires  int64
+	Modified int64
+}
+
+var rrSaveModel *RRSave // only use this as parameter for database.EnsureModel-like functions
+
+func init() {
+	database.RegisterModel(rrSaveModel, func() database.Model { return new(RRSave) })
+}
+
+// Create saves RRSave with the provided name in the default namespace.
+func (m *RRSave) Create(name string) error {
+	return m.CreateObject(&database.DNSCache, name, m)
+}
+
+// CreateWithType saves RRSave with the provided name and type in the default namespace.
+func (m *RRSave) CreateWithType(name string, qtype dns.Type) error {
+	return m.Create(fmt.Sprintf("%s%s", name, qtype.String()))
+}
+
+// CreateInNamespace saves RRSave with the provided name in the provided namespace.
+func (m *RRSave) CreateInNamespace(namespace *datastore.Key, name string) error {
+	return m.CreateObject(namespace, name, m)
+}
+
+// Save saves RRSave.
+func (m *RRSave) Save() error {
+	return m.SaveObject(m)
+}
+
+// GetRRSave fetches RRSave with the provided name in the default namespace.
+func GetRRSave(name string, qtype dns.Type) (*RRSave, error) {
+	return GetRRSaveFromNamespace(&database.DNSCache, name, qtype)
+}
+
+// GetRRSaveFromNamespace fetches RRSave with the provided name in the provided namespace.
+func GetRRSaveFromNamespace(namespace *datastore.Key, name string, qtype dns.Type) (*RRSave, error) {
+	object, err := database.GetAndEnsureModel(namespace, fmt.Sprintf("%s%s", name, qtype.String()), rrSaveModel)
+	if err != nil {
+		return nil, err
+	}
+	model, ok := object.(*RRSave)
+	if !ok {
+		return nil, database.NewMismatchError(object, rrSaveModel)
+	}
+	return model, nil
+}