[client] Set up firewall rules for dns routes dynamically based on dns response (#3702)

client/firewall/manager/firewall.go

@@ -1,13 +1,10 @@
 package manager
 
 import (
-	"crypto/sha256"
-	"encoding/hex"
 	"fmt"
 	"net"
 	"net/netip"
 	"sort"
-	"strings"
 
 	log "github.com/sirupsen/logrus"
 
@@ -43,6 +40,18 @@ const (
 // Action is the action to be taken on a rule
 type Action int
 
+// String returns the string representation of the action
+func (a Action) String() string {
+	switch a {
+	case ActionAccept:
+		return "accept"
+	case ActionDrop:
+		return "drop"
+	default:
+		return "unknown"
+	}
+}
+
 const (
 	// ActionAccept is the action to accept a packet
 	ActionAccept Action = iota
@@ -50,6 +59,33 @@ const (
 	ActionDrop
 )
 
+// Network is a rule destination, either a set or a prefix
+type Network struct {
+	Set    Set
+	Prefix netip.Prefix
+}
+
+// String returns the string representation of the destination
+func (d Network) String() string {
+	if d.Prefix.IsValid() {
+		return d.Prefix.String()
+	}
+	if d.IsSet() {
+		return d.Set.HashedName()
+	}
+	return "<invalid network>"
+}
+
+// IsSet returns true if the destination is a set
+func (d Network) IsSet() bool {
+	return d.Set != Set{}
+}
+
+// IsPrefix returns true if the destination is a valid prefix
+func (d Network) IsPrefix() bool {
+	return d.Prefix.IsValid()
+}
+
 // Manager is the high level abstraction of a firewall manager
 //
 // It declares methods which handle actions required by the
@@ -83,10 +119,9 @@ type Manager interface {
 	AddRouteFiltering(
 		id []byte,
 		sources []netip.Prefix,
-		destination netip.Prefix,
+		destination Network,
 		proto Protocol,
-		sPort *Port,
-		dPort *Port,
+		sPort, dPort *Port,
 		action Action,
 	) (Rule, error)
 
@@ -119,6 +154,9 @@ type Manager interface {
 
 	// DeleteDNATRule deletes a DNAT rule
 	DeleteDNATRule(Rule) error
+
+	// UpdateSet updates the set with the given prefixes
+	UpdateSet(hash Set, prefixes []netip.Prefix) error
 }
 
 func GenKey(format string, pair RouterPair) string {
@@ -153,22 +191,6 @@ func SetLegacyManagement(router LegacyManager, isLegacy bool) error {
 	return nil
 }
 
-// GenerateSetName generates a unique name for an ipset based on the given sources.
-func GenerateSetName(sources []netip.Prefix) string {
-	// sort for consistent naming
-	SortPrefixes(sources)
-
-	var sourcesStr strings.Builder
-	for _, src := range sources {
-		sourcesStr.WriteString(src.String())
-	}
-
-	hash := sha256.Sum256([]byte(sourcesStr.String()))
-	shortHash := hex.EncodeToString(hash[:])[:8]
-
-	return fmt.Sprintf("nb-%s", shortHash)
-}
-
 // MergeIPRanges merges overlapping IP ranges and returns a slice of non-overlapping netip.Prefix
 func MergeIPRanges(prefixes []netip.Prefix) []netip.Prefix {
 	if len(prefixes) == 0 {

client/firewall/manager/firewall_test.go

@@ -20,8 +20,8 @@ func TestGenerateSetName(t *testing.T) {
 			netip.MustParsePrefix("192.168.1.0/24"),
 		}
 
-		result1 := manager.GenerateSetName(prefixes1)
-		result2 := manager.GenerateSetName(prefixes2)
+		result1 := manager.NewPrefixSet(prefixes1)
+		result2 := manager.NewPrefixSet(prefixes2)
 
 		if result1 != result2 {
 			t.Errorf("Different orders produced different hashes: %s != %s", result1, result2)
@@ -34,9 +34,9 @@ func TestGenerateSetName(t *testing.T) {
 			netip.MustParsePrefix("10.0.0.0/8"),
 		}
 
-		result := manager.GenerateSetName(prefixes)
+		result := manager.NewPrefixSet(prefixes)
 
-		matched, err := regexp.MatchString(`^nb-[0-9a-f]{8}$`, result)
+		matched, err := regexp.MatchString(`^nb-[0-9a-f]{8}$`, result.HashedName())
 		if err != nil {
 			t.Fatalf("Error matching regex: %v", err)
 		}
@@ -46,8 +46,8 @@ func TestGenerateSetName(t *testing.T) {
 	})
 
 	t.Run("Empty input produces consistent result", func(t *testing.T) {
-		result1 := manager.GenerateSetName([]netip.Prefix{})
-		result2 := manager.GenerateSetName([]netip.Prefix{})
+		result1 := manager.NewPrefixSet([]netip.Prefix{})
+		result2 := manager.NewPrefixSet([]netip.Prefix{})
 
 		if result1 != result2 {
 			t.Errorf("Empty input produced inconsistent results: %s != %s", result1, result2)
@@ -64,8 +64,8 @@ func TestGenerateSetName(t *testing.T) {
 			netip.MustParsePrefix("192.168.1.0/24"),
 		}
 
-		result1 := manager.GenerateSetName(prefixes1)
-		result2 := manager.GenerateSetName(prefixes2)
+		result1 := manager.NewPrefixSet(prefixes1)
+		result2 := manager.NewPrefixSet(prefixes2)
 
 		if result1 != result2 {
 			t.Errorf("Different orders of IPv4 and IPv6 produced different hashes: %s != %s", result1, result2)

client/firewall/manager/routerpair.go

@@ -1,15 +1,13 @@
 package manager
 
 import (
-	"net/netip"
-
 	"github.com/netbirdio/netbird/route"
 )
 
 type RouterPair struct {
 	ID          route.ID
-	Source      netip.Prefix
-	Destination netip.Prefix
+	Source      Network
+	Destination Network
 	Masquerade  bool
 	Inverse     bool
 }

client/firewall/manager/set.go

@@ -0,0 +1,74 @@
+package manager
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"net/netip"
+	"slices"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/management/domain"
+)
+
+type Set struct {
+	hash    [4]byte
+	comment string
+}
+
+// String returns the string representation of the set: hashed name and comment
+func (h Set) String() string {
+	if h.comment == "" {
+		return h.HashedName()
+	}
+	return h.HashedName() + ": " + h.comment
+}
+
+// HashedName returns the string representation of the hash
+func (h Set) HashedName() string {
+	return fmt.Sprintf(
+		"nb-%s",
+		hex.EncodeToString(h.hash[:]),
+	)
+}
+
+// Comment returns the comment of the set
+func (h Set) Comment() string {
+	return h.comment
+}
+
+// NewPrefixSet generates a unique name for an ipset based on the given prefixes.
+func NewPrefixSet(prefixes []netip.Prefix) Set {
+	// sort for consistent naming
+	SortPrefixes(prefixes)
+
+	hash := sha256.New()
+	for _, src := range prefixes {
+		bytes, err := src.MarshalBinary()
+		if err != nil {
+			log.Warnf("failed to marshal prefix %s: %v", src, err)
+		}
+		hash.Write(bytes)
+	}
+	var set Set
+	copy(set.hash[:], hash.Sum(nil)[:4])
+
+	return set
+}
+
+// NewDomainSet generates a unique name for an ipset based on the given domains.
+func NewDomainSet(domains domain.List) Set {
+	slices.Sort(domains)
+
+	hash := sha256.New()
+	for _, d := range domains {
+		hash.Write([]byte(d.PunycodeString()))
+	}
+	set := Set{
+		comment: domains.SafeString(),
+	}
+	copy(set.hash[:], hash.Sum(nil)[:4])
+
+	return set
+}