github.com/kaisenlinux/docker.io@v0.0.0-20230510090727-ea55db55fac7/libnetwork/portallocator/portallocator_freebsd.go (about)

     1  package portallocator
     2  
     3  import (
     4  	"bytes"
     5  	"fmt"
     6  	"os/exec"
     7  )
     8  
     9  func getDynamicPortRange() (start int, end int, err error) {
    10  	portRangeKernelSysctl := []string{"net.inet.ip.portrange.hifirst", "net.ip.portrange.hilast"}
    11  	portRangeFallback := fmt.Sprintf("using fallback port range %d-%d", defaultPortRangeStart, defaultPortRangeEnd)
    12  	portRangeLowCmd := exec.Command("/sbin/sysctl", portRangeKernelSysctl[0])
    13  	var portRangeLowOut bytes.Buffer
    14  	portRangeLowCmd.Stdout = &portRangeLowOut
    15  	cmdErr := portRangeLowCmd.Run()
    16  	if cmdErr != nil {
    17  		return 0, 0, fmt.Errorf("port allocator - sysctl net.inet.ip.portrange.hifirst failed - %s: %v", portRangeFallback, err)
    18  	}
    19  	n, err := fmt.Sscanf(portRangeLowOut.String(), "%d", &start)
    20  	if n != 1 || err != nil {
    21  		if err == nil {
    22  			err = fmt.Errorf("unexpected count of parsed numbers (%d)", n)
    23  		}
    24  		return 0, 0, fmt.Errorf("port allocator - failed to parse system ephemeral port range start from %s - %s: %v", portRangeLowOut.String(), portRangeFallback, err)
    25  	}
    26  
    27  	portRangeHighCmd := exec.Command("/sbin/sysctl", portRangeKernelSysctl[1])
    28  	var portRangeHighOut bytes.Buffer
    29  	portRangeHighCmd.Stdout = &portRangeHighOut
    30  	cmdErr = portRangeHighCmd.Run()
    31  	if cmdErr != nil {
    32  		return 0, 0, fmt.Errorf("port allocator - sysctl net.inet.ip.portrange.hilast failed - %s: %v", portRangeFallback, err)
    33  	}
    34  	n, err = fmt.Sscanf(portRangeHighOut.String(), "%d", &end)
    35  	if n != 1 || err != nil {
    36  		if err == nil {
    37  			err = fmt.Errorf("unexpected count of parsed numbers (%d)", n)
    38  		}
    39  		return 0, 0, fmt.Errorf("port allocator - failed to parse system ephemeral port range end from %s - %s: %v", portRangeHighOut.String(), portRangeFallback, err)
    40  	}
    41  	return start, end, nil
    42  }