util/deephash: move internal/deephash to util/deephash

No code changes. Just a minor package doc addition about lack of API stability.
2021-07-02 21:30:29 -07:00
parent 7f095617f2
commit 700badd8f8
8 changed files with 6 additions and 3 deletions
--- a/util/deephash/deephash_test.go
+++ b/util/deephash/deephash_test.go
@ -0,0 +1,147 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package deephash
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"inet.af/netaddr"
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/dnsname"
+	"tailscale.com/wgengine/router"
+	"tailscale.com/wgengine/wgcfg"
+)
+
+func TestDeepHash(t *testing.T) {
+	// v contains the types of values we care about for our current callers.
+	// Mostly we're just testing that we don't panic on handled types.
+	v := getVal()
+
+	hash1 := calcHash(v)
+	t.Logf("hash: %v", hash1)
+	for i := 0; i < 20; i++ {
+		hash2 := calcHash(getVal())
+		if hash1 != hash2 {
+			t.Error("second hash didn't match")
+		}
+	}
+}
+
+func getVal() []interface{} {
+	return []interface{}{
+		&wgcfg.Config{
+			Name:      "foo",
+			Addresses: []netaddr.IPPrefix{netaddr.IPPrefixFrom(netaddr.IPFrom16([16]byte{3: 3}), 5)},
+			Peers: []wgcfg.Peer{
+				{
+					Endpoints: wgcfg.Endpoints{
+						IPPorts: wgcfg.NewIPPortSet(netaddr.MustParseIPPort("42.42.42.42:5")),
+					},
+				},
+			},
+		},
+		&router.Config{
+			Routes: []netaddr.IPPrefix{
+				netaddr.MustParseIPPrefix("1.2.3.0/24"),
+				netaddr.MustParseIPPrefix("1234::/64"),
+			},
+		},
+		map[dnsname.FQDN][]netaddr.IP{
+			dnsname.FQDN("a."): {netaddr.MustParseIP("1.2.3.4"), netaddr.MustParseIP("4.3.2.1")},
+			dnsname.FQDN("b."): {netaddr.MustParseIP("8.8.8.8"), netaddr.MustParseIP("9.9.9.9")},
+			dnsname.FQDN("c."): {netaddr.MustParseIP("6.6.6.6"), netaddr.MustParseIP("7.7.7.7")},
+			dnsname.FQDN("d."): {netaddr.MustParseIP("6.7.6.6"), netaddr.MustParseIP("7.7.7.8")},
+			dnsname.FQDN("e."): {netaddr.MustParseIP("6.8.6.6"), netaddr.MustParseIP("7.7.7.9")},
+			dnsname.FQDN("f."): {netaddr.MustParseIP("6.9.6.6"), netaddr.MustParseIP("7.7.7.0")},
+		},
+		map[dnsname.FQDN][]netaddr.IPPort{
+			dnsname.FQDN("a."): {netaddr.MustParseIPPort("1.2.3.4:11"), netaddr.MustParseIPPort("4.3.2.1:22")},
+			dnsname.FQDN("b."): {netaddr.MustParseIPPort("8.8.8.8:11"), netaddr.MustParseIPPort("9.9.9.9:22")},
+			dnsname.FQDN("c."): {netaddr.MustParseIPPort("8.8.8.8:12"), netaddr.MustParseIPPort("9.9.9.9:23")},
+			dnsname.FQDN("d."): {netaddr.MustParseIPPort("8.8.8.8:13"), netaddr.MustParseIPPort("9.9.9.9:24")},
+			dnsname.FQDN("e."): {netaddr.MustParseIPPort("8.8.8.8:14"), netaddr.MustParseIPPort("9.9.9.9:25")},
+		},
+		map[tailcfg.DiscoKey]bool{
+			{1: 1}: true,
+			{1: 2}: false,
+			{2: 3}: true,
+			{3: 4}: false,
+		},
+	}
+}
+
+func BenchmarkHash(b *testing.B) {
+	b.ReportAllocs()
+	v := getVal()
+	for i := 0; i < b.N; i++ {
+		calcHash(v)
+	}
+}
+
+func TestHashMapAcyclic(t *testing.T) {
+	m := map[int]string{}
+	for i := 0; i < 100; i++ {
+		m[i] = fmt.Sprint(i)
+	}
+	got := map[string]bool{}
+
+	var buf bytes.Buffer
+	bw := bufio.NewWriter(&buf)
+
+	for i := 0; i < 20; i++ {
+		visited := map[uintptr]bool{}
+		scratch := make([]byte, 0, 64)
+		v := reflect.ValueOf(m)
+		buf.Reset()
+		bw.Reset(&buf)
+		if !hashMapAcyclic(bw, v, visited, scratch) {
+			t.Fatal("returned false")
+		}
+		if got[string(buf.Bytes())] {
+			continue
+		}
+		got[string(buf.Bytes())] = true
+	}
+	if len(got) != 1 {
+		t.Errorf("got %d results; want 1", len(got))
+	}
+}
+
+func BenchmarkHashMapAcyclic(b *testing.B) {
+	b.ReportAllocs()
+	m := map[int]string{}
+	for i := 0; i < 100; i++ {
+		m[i] = fmt.Sprint(i)
+	}
+
+	var buf bytes.Buffer
+	bw := bufio.NewWriter(&buf)
+	visited := map[uintptr]bool{}
+	scratch := make([]byte, 0, 64)
+	v := reflect.ValueOf(m)
+
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		bw.Reset(&buf)
+		if !hashMapAcyclic(bw, v, visited, scratch) {
+			b.Fatal("returned false")
+		}
+	}
+}
+
+func TestExhaustive(t *testing.T) {
+	seen := make(map[string]bool)
+	for i := 0; i < 100000; i++ {
+		s := calcHash(i)
+		if seen[s] {
+			t.Fatalf("hash collision %v", i)
+		}
+		seen[s] = true
+	}
+}