New hashing algorithm for fingerprint processor (elastic#15418)

* XXHash configuration and test

* Removed unused option

* Inlining function

* Changelog documentation

* xxhash library vendored

* Updated changelog

* Update NOTICE.txt

* * Update version github.com/OneOfOne/xxhash@1.2.7
* Using a new constructor function xxhash.NewHash64

* Add xxhash as option for hashing algorithm in fingerprint's docs

* Update NOTICE.txt

CHANGELOG.next.asciidoc

@@ -114,6 +114,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add `add_id` processor. {pull}14524[14524]
 - Enable TLS 1.3 in all beats. {pull}12973[12973]
 - Spooling to disk creates a lockfile on each platform. {pull}15338[15338]
+- Fingerprint processor adds a new xxhash hashing algorithm {pull}15418[15418]
 
 *Auditbeat*
 

NOTICE.txt

@@ -4521,6 +4521,16 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 
+--------------------------------------------------------------------
+Dependency: github.com/OneOfOne/xxhash
+Version: v1.2.7
+Revision: 85d5025fe15b385888b1886ea99f722f549a6934
+License type (autodetected): Apache-2.0
+./vendor/github.com/OneOfOne/xxhash/LICENSE:
+--------------------------------------------------------------------
+Apache License 2.0
+
+
 --------------------------------------------------------------------
 Dependency: github.com/opencontainers/go-digest
 Revision: ac19fd6e7483ff933754af248d80be865e543d22

libbeat/processors/fingerprint/docs/fingerprint.asciidoc

@@ -16,5 +16,5 @@ The following settings are supported:
 `fields`:: List of fields to use as the source for the fingerprint.
 `ignore_missing`:: (Optional) Whether to ignore missing fields. Default is `false`.
 `target_field`:: (Optional) Field in which the generated fingerprint should be stored. Default is `fingerprint`.
-`method`:: (Optional) Algorithm to use for computing the fingerprint. Must be one of: `md5`, `sha1`, `sha256`, `sha384`, `sha512`. Default is `sha256`.
+`method`:: (Optional) Algorithm to use for computing the fingerprint. Must be one of: `md5`, `sha1`, `sha256`, `sha384`, `sha512`, `xxhash`. Default is `sha256`.
 `encoding`:: (Optional) Encoding to use on the fingerprint value. Must be one of `hex`, `base32`, or `base64`. Default is `hex`.

libbeat/processors/fingerprint/fingerprint_test.go

@@ -43,6 +43,7 @@ func TestHashMethods(t *testing.T) {
 		"sha256": {"1208288932231e313b369bae587ff574cd3016a408e52e7128d7bee752674003"},
 		"sha384": {"295adfe0bc03908948e4b0b6a54f441767867e426dda590430459c8a147fbba242a38cba282adee78335b9e08877b86c"},
 		"sha512": {"f50ad51b63c92a0ed0c910527119b81806f3110f0afaa1dcb93506a78371ea761e50c0fc09b08c441d832dd2da1b45e5d8361adfb240e1fffc2695122a23e183"},
+		"xxhash": {"37bc50682fba6686"},
 	}
 
 	for method, test := range tests {

libbeat/processors/fingerprint/hash.go

@@ -24,6 +24,8 @@ import (
 	"crypto/sha512"
 	"hash"
 	"strings"
+
+	"github.com/OneOfOne/xxhash"
 )
 
 type hashMethod func() hash.Hash
@@ -34,6 +36,7 @@ var hashes = map[string]hashMethod{
 	"sha256": sha256.New,
 	"sha384": sha512.New384,
 	"sha512": sha512.New,
+	"xxhash": xxhash.NewHash64,
 }
 
 // Unpack creates the hashMethod from the given string