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

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
+}