Replace test_runner.sh bash script with Go.

PiperOrigin-RevId: 311285868

2 files changed, 119 insertions, 0 deletions

diff --git a/test/packetimpact/netdevs/BUILD b/test/packetimpact/netdevs/BUILD
new file mode 100644
index 000000000..422bb9b0c
--- /dev/null
+++ b/test/packetimpact/netdevs/BUILD
@@ -0,0 +1,15 @@
+load("//tools:defs.bzl", "go_library")
+
+package(
+    licenses = ["notice"],
+)
+
+go_library(
+    name = "netdevs",
+    srcs = ["netdevs.go"],
+    visibility = ["//test/packetimpact:__subpackages__"],
+    deps = [
+        "//pkg/tcpip",
+        "//pkg/tcpip/header",
+    ],
+)
diff --git a/test/packetimpact/netdevs/netdevs.go b/test/packetimpact/netdevs/netdevs.go
new file mode 100644
index 000000000..d2c9cfeaf
--- /dev/null
+++ b/test/packetimpact/netdevs/netdevs.go
@@ -0,0 +1,104 @@
+// Copyright 2020 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 netdevs contains utilities for working with network devices.
+package netdevs
+
+import (
+	"fmt"
+	"net"
+	"regexp"
+	"strings"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+)
+
+// A DeviceInfo represents a network device.
+type DeviceInfo struct {
+	MAC      net.HardwareAddr
+	IPv4Addr net.IP
+	IPv4Net  *net.IPNet
+	IPv6Addr net.IP
+	IPv6Net  *net.IPNet
+}
+
+var (
+	deviceLine = regexp.MustCompile(`^\s*\d+: (\w+)`)
+	linkLine   = regexp.MustCompile(`^\s*link/\w+ ([0-9a-fA-F:]+)`)
+	inetLine   = regexp.MustCompile(`^\s*inet ([0-9./]+)`)
+	inet6Line  = regexp.MustCompile(`^\s*inet6 ([0-9a-fA-Z:/]+)`)
+)
+
+// ParseDevices parses the output from `ip addr show` into a map from device
+// name to information about the device.
+func ParseDevices(cmdOutput string) (map[string]DeviceInfo, error) {
+	var currentDevice string
+	var currentInfo DeviceInfo
+	deviceInfos := make(map[string]DeviceInfo)
+	for _, line := range strings.Split(cmdOutput, "\n") {
+		if m := deviceLine.FindStringSubmatch(line); m != nil {
+			if currentDevice != "" {
+				deviceInfos[currentDevice] = currentInfo
+			}
+			currentInfo = DeviceInfo{}
+			currentDevice = m[1]
+		} else if m := linkLine.FindStringSubmatch(line); m != nil {
+			mac, err := net.ParseMAC(m[1])
+			if err != nil {
+				return nil, err
+			}
+			currentInfo.MAC = mac
+		} else if m := inetLine.FindStringSubmatch(line); m != nil {
+			ipv4Addr, ipv4Net, err := net.ParseCIDR(m[1])
+			if err != nil {
+				return nil, err
+			}
+			currentInfo.IPv4Addr = ipv4Addr
+			currentInfo.IPv4Net = ipv4Net
+		} else if m := inet6Line.FindStringSubmatch(line); m != nil {
+			ipv6Addr, ipv6Net, err := net.ParseCIDR(m[1])
+			if err != nil {
+				return nil, err
+			}
+			currentInfo.IPv6Addr = ipv6Addr
+			currentInfo.IPv6Net = ipv6Net
+		}
+	}
+	if currentDevice != "" {
+		deviceInfos[currentDevice] = currentInfo
+	}
+	return deviceInfos, nil
+}
+
+// MACToIP converts the MAC address to an IPv6 link local address as described
+// in RFC 4291 page 20: https://tools.ietf.org/html/rfc4291#page-20
+func MACToIP(mac net.HardwareAddr) net.IP {
+	addr := make([]byte, header.IPv6AddressSize)
+	addr[0] = 0xfe
+	addr[1] = 0x80
+	header.EthernetAdddressToModifiedEUI64IntoBuf(tcpip.LinkAddress(mac), addr[8:])
+	return net.IP(addr)
+}
+
+// FindDeviceByIP finds a DeviceInfo and device name from an IP address in the
+// output of ParseDevices.
+func FindDeviceByIP(ip net.IP, devices map[string]DeviceInfo) (string, DeviceInfo, error) {
+	for dev, info := range devices {
+		if info.IPv4Addr.Equal(ip) {
+			return dev, info, nil
+		}
+	}
+	return "", DeviceInfo{}, fmt.Errorf("can't find %s on any interface", ip)
+}