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util_linux.go
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util_linux.go
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// +build linux
package ocicni
import (
"fmt"
"net"
"os/exec"
"strings"
)
var defaultNamespaceEnterCommandName = "nsenter"
type nsManager struct {
nsenterPath string
}
func (nsm *nsManager) init() error {
var err error
nsm.nsenterPath, err = exec.LookPath(defaultNamespaceEnterCommandName)
return err
}
func getContainerDetails(nsm *nsManager, netnsPath, interfaceName, addrType string) (*net.IPNet, *net.HardwareAddr, error) {
// Try to retrieve ip inside container network namespace
output, err := exec.Command(nsm.nsenterPath, fmt.Sprintf("--net=%s", netnsPath), "-F", "--",
"ip", "-o", addrType, "addr", "show", "dev", interfaceName, "scope", "global").CombinedOutput()
if err != nil {
return nil, nil, fmt.Errorf("Unexpected command output %s with error: %v", output, err)
}
lines := strings.Split(string(output), "\n")
if len(lines) < 1 {
return nil, nil, fmt.Errorf("Unexpected command output %s", output)
}
fields := strings.Fields(lines[0])
if len(fields) < 4 {
return nil, nil, fmt.Errorf("Unexpected address output %s ", lines[0])
}
ip, ipNet, err := net.ParseCIDR(fields[3])
if err != nil {
return nil, nil, fmt.Errorf("CNI failed to parse ip from output %s due to %v", output, err)
}
if ip.To4() == nil {
ipNet.IP = ip
} else {
ipNet.IP = ip.To4()
}
// Try to retrieve MAC inside container network namespace
output, err = exec.Command(nsm.nsenterPath, fmt.Sprintf("--net=%s", netnsPath), "-F", "--",
"ip", "link", "show", "dev", interfaceName).CombinedOutput()
if err != nil {
return nil, nil, fmt.Errorf("unexpected 'ip link' command output %s with error: %v", output, err)
}
lines = strings.Split(string(output), "\n")
if len(lines) < 2 {
return nil, nil, fmt.Errorf("unexpected 'ip link' command output %s", output)
}
fields = strings.Fields(lines[1])
if len(fields) < 4 {
return nil, nil, fmt.Errorf("unexpected link output %s ", lines[0])
}
mac, err := net.ParseMAC(fields[1])
if err != nil {
return nil, nil, fmt.Errorf("failed to parse MAC from output %s due to %v", output, err)
}
return ipNet, &mac, nil
}