152 lines
3.8 KiB
Go
152 lines
3.8 KiB
Go
// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package iptables
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import (
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"fmt"
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"net"
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"os/exec"
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"time"
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"gvisor.dev/gvisor/runsc/testutil"
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)
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const iptablesBinary = "iptables"
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// filterTable calls `iptables -t filter` with the given args.
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func filterTable(args ...string) error {
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return tableCmd("filter", args)
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}
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// natTable calls `iptables -t nat` with the given args.
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func natTable(args ...string) error {
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return tableCmd("nat", args)
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}
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func tableCmd(table string, args []string) error {
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args = append([]string{"-t", table}, args...)
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cmd := exec.Command(iptablesBinary, args...)
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if out, err := cmd.CombinedOutput(); err != nil {
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return fmt.Errorf("error running iptables with args %v\nerror: %v\noutput: %s", args, err, string(out))
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}
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return nil
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}
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// filterTableRules is like filterTable, but runs multiple iptables commands.
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func filterTableRules(argsList [][]string) error {
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for _, args := range argsList {
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if err := filterTable(args...); err != nil {
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return err
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}
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}
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return nil
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}
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// listenUDP listens on a UDP port and returns the value of net.Conn.Read() for
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// the first read on that port.
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func listenUDP(port int, timeout time.Duration) error {
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localAddr := net.UDPAddr{
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Port: port,
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}
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conn, err := net.ListenUDP(network, &localAddr)
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if err != nil {
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return err
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}
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defer conn.Close()
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conn.SetDeadline(time.Now().Add(timeout))
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_, err = conn.Read([]byte{0})
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return err
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}
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// sendUDPLoop sends 1 byte UDP packets repeatedly to the IP and port specified
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// over a duration.
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func sendUDPLoop(ip net.IP, port int, duration time.Duration) error {
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// Send packets for a few seconds.
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remote := net.UDPAddr{
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IP: ip,
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Port: port,
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}
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conn, err := net.DialUDP(network, nil, &remote)
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if err != nil {
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return err
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}
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defer conn.Close()
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to := time.After(duration)
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for timedOut := false; !timedOut; {
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// This may return an error (connection refused) if the remote
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// hasn't started listening yet or they're dropping our
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// packets. So we ignore Write errors and depend on the remote
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// to report a failure if it doesn't get a packet it needs.
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conn.Write([]byte{0})
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select {
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case <-to:
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timedOut = true
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default:
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time.Sleep(200 * time.Millisecond)
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}
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}
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return nil
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}
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// listenTCP listens for connections on a TCP port.
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func listenTCP(port int, timeout time.Duration) error {
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localAddr := net.TCPAddr{
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Port: port,
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}
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// Starts listening on port.
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lConn, err := net.ListenTCP("tcp4", &localAddr)
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if err != nil {
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return err
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}
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defer lConn.Close()
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// Accept connections on port.
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lConn.SetDeadline(time.Now().Add(timeout))
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conn, err := lConn.AcceptTCP()
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if err != nil {
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return err
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}
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conn.Close()
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return nil
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}
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// connectTCP connects the TCP server over specified local port, server IP and remote/server port.
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func connectTCP(ip net.IP, remotePort, localPort int, timeout time.Duration) error {
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contAddr := net.TCPAddr{
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IP: ip,
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Port: remotePort,
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}
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// The container may not be listening when we first connect, so retry
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// upon error.
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callback := func() error {
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localAddr := net.TCPAddr{
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Port: localPort,
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}
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conn, err := net.DialTCP("tcp4", &localAddr, &contAddr)
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if conn != nil {
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conn.Close()
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}
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return err
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}
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if err := testutil.Poll(callback, timeout); err != nil {
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return fmt.Errorf("timed out waiting to send IP, most recent error: %v", err)
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}
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return nil
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}
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