| package portallocator |
| |
| import ( |
| "bytes" |
| "fmt" |
| "os/exec" |
| ) |
| |
| func getDynamicPortRange() (start int, end int, err error) { |
| portRangeKernelSysctl := []string{"net.inet.ip.portrange.hifirst", "net.ip.portrange.hilast"} |
| portRangeLowCmd := exec.Command("/sbin/sysctl", portRangeKernelSysctl[0]) |
| var portRangeLowOut bytes.Buffer |
| portRangeLowCmd.Stdout = &portRangeLowOut |
| cmdErr := portRangeLowCmd.Run() |
| if cmdErr != nil { |
| return 0, 0, fmt.Errorf("port allocator - sysctl net.inet.ip.portrange.hifirst failed: %v", err) |
| } |
| n, err := fmt.Sscanf(portRangeLowOut.String(), "%d", &start) |
| if n != 1 || err != nil { |
| if err == nil { |
| err = fmt.Errorf("unexpected count of parsed numbers (%d)", n) |
| } |
| return 0, 0, fmt.Errorf("port allocator - failed to parse system ephemeral port range start from %s: %v", portRangeLowOut.String(), err) |
| } |
| |
| portRangeHighCmd := exec.Command("/sbin/sysctl", portRangeKernelSysctl[1]) |
| var portRangeHighOut bytes.Buffer |
| portRangeHighCmd.Stdout = &portRangeHighOut |
| cmdErr = portRangeHighCmd.Run() |
| if cmdErr != nil { |
| return 0, 0, fmt.Errorf("port allocator - sysctl net.inet.ip.portrange.hilast failed: %v", err) |
| } |
| n, err = fmt.Sscanf(portRangeHighOut.String(), "%d", &end) |
| if n != 1 || err != nil { |
| if err == nil { |
| err = fmt.Errorf("unexpected count of parsed numbers (%d)", n) |
| } |
| return 0, 0, fmt.Errorf("port allocator - failed to parse system ephemeral port range end from %s: %v", portRangeHighOut.String(), err) |
| } |
| return start, end, nil |
| } |