77 lines
2 KiB
Go
77 lines
2 KiB
Go
// +build !windows
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package libnetwork
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import (
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"fmt"
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"net"
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"os"
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"os/exec"
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"runtime"
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log "github.com/Sirupsen/logrus"
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"github.com/docker/docker/pkg/reexec"
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"github.com/docker/libnetwork/iptables"
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"github.com/vishvananda/netns"
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)
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func init() {
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reexec.Register("setup-resolver", reexecSetupResolver)
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}
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func reexecSetupResolver() {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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if len(os.Args) < 4 {
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log.Error("invalid number of arguments..")
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os.Exit(1)
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}
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_, ipPort, _ := net.SplitHostPort(os.Args[2])
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_, tcpPort, _ := net.SplitHostPort(os.Args[3])
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rules := [][]string{
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{"-t", "nat", "-A", "OUTPUT", "-d", resolverIP, "-p", "udp", "--dport", dnsPort, "-j", "DNAT", "--to-destination", os.Args[2]},
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{"-t", "nat", "-A", "POSTROUTING", "-s", resolverIP, "-p", "udp", "--sport", ipPort, "-j", "SNAT", "--to-source", ":" + dnsPort},
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{"-t", "nat", "-A", "OUTPUT", "-d", resolverIP, "-p", "tcp", "--dport", dnsPort, "-j", "DNAT", "--to-destination", os.Args[3]},
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{"-t", "nat", "-A", "POSTROUTING", "-s", resolverIP, "-p", "tcp", "--sport", tcpPort, "-j", "SNAT", "--to-source", ":" + dnsPort},
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}
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f, err := os.OpenFile(os.Args[1], os.O_RDONLY, 0)
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if err != nil {
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log.Errorf("failed get network namespace %q: %v", os.Args[1], err)
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os.Exit(2)
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}
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defer f.Close()
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nsFD := f.Fd()
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if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
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log.Errorf("setting into container net ns %v failed, %v", os.Args[1], err)
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os.Exit(3)
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}
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for _, rule := range rules {
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if iptables.RawCombinedOutputNative(rule...) != nil {
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log.Errorf("setting up rule failed, %v", rule)
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}
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}
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}
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func (r *resolver) setupIPTable() error {
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if r.err != nil {
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return r.err
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}
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laddr := r.conn.LocalAddr().String()
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ltcpaddr := r.tcpListen.Addr().String()
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cmd := &exec.Cmd{
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Path: reexec.Self(),
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Args: append([]string{"setup-resolver"}, r.sb.Key(), laddr, ltcpaddr),
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Stdout: os.Stdout,
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Stderr: os.Stderr,
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}
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if err := cmd.Run(); err != nil {
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return fmt.Errorf("reexec failed: %v", err)
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}
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return nil
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}
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