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moby--moby/libnetwork/drivers/bridge/setup_ip_forwarding.go
Tomas Kral 5a259d55f0 modify /proc/sys only if needed
fixes #405

Signed-off-by: Tomas Kral <tomas.kral@gmail.com>
2015-08-05 13:46:28 +02:00

29 lines
656 B
Go

package bridge
import (
"fmt"
"io/ioutil"
)
const (
ipv4ForwardConf = "/proc/sys/net/ipv4/ip_forward"
ipv4ForwardConfPerm = 0644
)
func setupIPForwarding() error {
// Get current IPv4 forward setup
ipv4ForwardData, err := ioutil.ReadFile(ipv4ForwardConf)
if err != nil {
return fmt.Errorf("Cannot read IP forwarding setup: %v", err)
}
// Enable IPv4 forwarding only if it is not already enabled
if ipv4ForwardData[0] != '1' {
// Enable IPv4 forwarding
if err := ioutil.WriteFile(ipv4ForwardConf, []byte{'1', '\n'}, ipv4ForwardConfPerm); err != nil {
return fmt.Errorf("Setup IP forwarding failed: %v", err)
}
}
return nil
}