| package portallocator |
| |
| import ( |
| "bufio" |
| "fmt" |
| "os" |
| ) |
| |
| func getDynamicPortRange() (start int, end int, err error) { |
| const portRangeKernelParam = "/proc/sys/net/ipv4/ip_local_port_range" |
| portRangeFallback := fmt.Sprintf("using fallback port range %d-%d", DefaultPortRangeStart, DefaultPortRangeEnd) |
| file, err := os.Open(portRangeKernelParam) |
| if err != nil { |
| return 0, 0, fmt.Errorf("port allocator - %s due to error: %v", portRangeFallback, err) |
| } |
| |
| defer file.Close() |
| |
| n, err := fmt.Fscanf(bufio.NewReader(file), "%d\t%d", &start, &end) |
| if n != 2 || 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 from %s - %s: %v", portRangeKernelParam, portRangeFallback, err) |
| } |
| return start, end, nil |
| } |
