Use nicer formatting for IP addresses in tests

This was semi-automated -- there are many addresses that were not replaced.
Future commits should clean those up.

Parse4 and Parse6 were given their own package because //pkg/test can introduce
dependency cycles, as it depends transitively on //pkg/tcpip and some other
netstack packages.

PiperOrigin-RevId: 368726528

1 files changed, 43 insertions, 0 deletions

diff --git a/pkg/tcpip/testutil/testutil.go b/pkg/tcpip/testutil/testutil.go
new file mode 100644
index 000000000..1aaed590f
--- /dev/null
+++ b/pkg/tcpip/testutil/testutil.go
@@ -0,0 +1,43 @@
+// Copyright 2021 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package testutil provides helper functions for netstack unit tests.
+package testutil
+
+import (
+	"fmt"
+	"net"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+)
+
+// MustParse4 parses an IPv4 string (e.g. "192.168.1.1") into a tcpip.Address.
+// Passing an IPv4-mapped IPv6 address will yield only the 4 IPv4 bytes.
+func MustParse4(addr string) tcpip.Address {
+	ip := net.ParseIP(addr).To4()
+	if ip == nil {
+		panic(fmt.Sprintf("Parse4 expects IPv4 addresses, but was passed %q", addr))
+	}
+	return tcpip.Address(ip)
+}
+
+// MustParse6 parses an IPv6 string (e.g. "fe80::1") into a tcpip.Address. Passing
+// an IPv4 address will yield an IPv4-mapped IPv6 address.
+func MustParse6(addr string) tcpip.Address {
+	ip := net.ParseIP(addr).To16()
+	if ip == nil {
+		panic(fmt.Sprintf("Parse6 was passed malformed address %q", addr))
+	}
+	return tcpip.Address(ip)
+}