func updateNamespaceNetworkLinks(pid int, ports io.Reader) error {
name := "netlink-" + strconv.Itoa(pid)
nsPath := fmt.Sprintf("/proc/%d/ns/net", pid)
path := fmt.Sprintf("/var/run/netns/%s", name)
if err := os.MkdirAll("/var/run/netns", 0755); err != nil {
return err
}
if err := os.Symlink(nsPath, path); err != nil && !os.IsExist(err) {
return err
}
defer os.Remove(path)
sourceAddr, errs := getHostIPFromNamespace(name)
if errs != nil {
return errs
}
// Enable routing in the namespace
output, err := exec.Command("ip", "netns", "exec", name, "sysctl", "-w", "net.ipv4.conf.all.route_localnet=1").Output()
if err != nil {
log.Printf("gear: Failed to enable localnet routing: %v", err)
log.Printf("gear: error output: %v", output)
return err
}
// Enable ip forwarding
output, err = exec.Command("ip", "netns", "exec", name, "sysctl", "-w", "net.ipv4.ip_forward=1").Output()
if err != nil {
log.Printf("gear: Failed to enable ipv4 forwarding: %v", err)
log.Printf("gear: error output: %v", output)
return err
}
// Restore a set of rules to the table
cmd := exec.Command("ip", "netns", "exec", name, "iptables-restore")
stdin, errp := cmd.StdinPipe()
if errp != nil {
log.Printf("gear: Could not open pipe to iptables-restore: %v", errp)
return errp
}
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
defer stdin.Close()
if err := cmd.Start(); err != nil {
log.Printf("gear: Could not start iptables-restore: %v", errp)
return err
}
fmt.Fprintf(stdin, "*nat\n")
for {
link := containers.NetworkLink{}
if _, err := fmt.Fscanf(ports, "%s\t%v\t%v\t%s\n", &link.FromHost, &link.FromPort, &link.ToPort, &link.ToHost); err != nil {
if err == io.EOF {
break
}
log.Printf("gear: Could not read from network links file: %v", err)
continue
}
if err := link.Check(); err != nil {
log.Printf("gear: Link in file is not valid: %v", err)
continue
}
if link.Complete() {
srcIP, err := net.ResolveIPAddr("ip", link.FromHost)
if err != nil {
log.Printf("gear: Link source host does not resolve %v", err)
continue
}
destIP, err := resolver.ResolveIP(link.ToHost)
if err != nil {
log.Printf("gear: Link destination host does not resolve %v", err)
continue
}
data := containers.OutboundNetworkIptables{sourceAddr.String(), srcIP.IP.String(), link.FromPort, destIP.String(), link.ToPort}
if err := containers.OutboundNetworkIptablesTemplate.Execute(stdin, &data); err != nil {
log.Printf("gear: Unable to write network link rules: %v", err)
return err
}
}
}
fmt.Fprintf(stdin, "COMMIT\n")
stdin.Close()
if err := cmd.Wait(); err != nil {
log.Printf("gear: iptables-restore did not successfully complete: %v", err)
return err
}
return nil
}
func updateNamespaceNetworkLinks(name string, sourceAddr *net.IPAddr, ports io.Reader) error {
// Enable routing in the namespace
output, err := exec.Command("ip", "netns", "exec", name, "sysctl", "-w", "net.ipv4.conf.all.route_localnet=1").Output()
if err != nil {
log.Printf("gear: Failed to enable localnet routing: %v", err)
log.Printf("gear: error output: %v", output)
return err
}
// Enable ip forwarding
output, err = exec.Command("ip", "netns", "exec", name, "sysctl", "-w", "net.ipv4.ip_forward=1").Output()
if err != nil {
log.Printf("gear: Failed to enable ipv4 forwarding: %v", err)
log.Printf("gear: error output: %v", output)
return err
}
// Restore a set of rules to the table
cmd := exec.Command("ip", "netns", "exec", name, "iptables-restore")
stdin, errp := cmd.StdinPipe()
if errp != nil {
log.Printf("gear: Could not open pipe to iptables-restore: %v", errp)
return errp
}
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
defer stdin.Close()
if err := cmd.Start(); err != nil {
log.Printf("gear: Could not start iptables-restore: %v", errp)
return err
}
fmt.Fprintf(stdin, "*nat\n")
for {
link := containers.NetworkLink{}
if _, err := fmt.Fscanf(ports, "%s\t%v\t%v\t%s\n", &link.FromHost, &link.FromPort, &link.ToPort, &link.ToHost); err != nil {
if err == io.EOF {
break
}
log.Printf("gear: Could not read from network links file: %v", err)
continue
}
if err := link.Check(); err != nil {
log.Printf("gear: Link in file is not valid: %v", err)
continue
}
if link.Complete() {
srcIP, err := net.ResolveIPAddr("ip", link.FromHost)
if err != nil {
log.Printf("gear: Link source host does not resolve %v", err)
continue
}
destIP, err := resolver.ResolveIP(link.ToHost)
if err != nil {
log.Printf("gear: Link destination host does not resolve %v", err)
continue
}
log.Printf("Mapping %s(%s):%d -> %s:%d", sourceAddr.String(), srcIP.String(), link.FromPort, destIP.String(), link.ToPort)
data := OutboundNetworkIptables{sourceAddr.String(), srcIP.IP.String(), link.FromPort, destIP.String(), link.ToPort}
if err := OutboundNetworkIptablesTemplate.Execute(stdin, &data); err != nil {
log.Printf("gear: Unable to write network link rules: %v", err)
return err
}
}
}
fmt.Fprintf(stdin, "COMMIT\n")
stdin.Close()
if err := cmd.Wait(); err != nil {
log.Printf("gear: iptables-restore did not successfully complete: %v", err)
return err
}
return nil
}
