Zack Williams | e940c7a | 2019-08-21 14:25:39 -0700 | [diff] [blame] | 1 | /* |
| 2 | Copyright 2015 The Kubernetes Authors. |
| 3 | |
| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | you may not use this file except in compliance with the License. |
| 6 | You may obtain a copy of the License at |
| 7 | |
| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | Unless required by applicable law or agreed to in writing, software |
| 11 | distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | See the License for the specific language governing permissions and |
| 14 | limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package net |
| 18 | |
| 19 | import ( |
| 20 | "fmt" |
| 21 | "strconv" |
| 22 | "strings" |
| 23 | ) |
| 24 | |
| 25 | // PortRange represents a range of TCP/UDP ports. To represent a single port, |
| 26 | // set Size to 1. |
| 27 | type PortRange struct { |
| 28 | Base int |
| 29 | Size int |
| 30 | } |
| 31 | |
| 32 | // Contains tests whether a given port falls within the PortRange. |
| 33 | func (pr *PortRange) Contains(p int) bool { |
| 34 | return (p >= pr.Base) && ((p - pr.Base) < pr.Size) |
| 35 | } |
| 36 | |
| 37 | // String converts the PortRange to a string representation, which can be |
| 38 | // parsed by PortRange.Set or ParsePortRange. |
| 39 | func (pr PortRange) String() string { |
| 40 | if pr.Size == 0 { |
| 41 | return "" |
| 42 | } |
| 43 | return fmt.Sprintf("%d-%d", pr.Base, pr.Base+pr.Size-1) |
| 44 | } |
| 45 | |
| 46 | // Set parses a string of the form "value", "min-max", or "min+offset", inclusive at both ends, and |
| 47 | // sets the PortRange from it. This is part of the flag.Value and pflag.Value |
| 48 | // interfaces. |
| 49 | func (pr *PortRange) Set(value string) error { |
| 50 | const ( |
| 51 | SinglePortNotation = 1 << iota |
| 52 | HyphenNotation |
| 53 | PlusNotation |
| 54 | ) |
| 55 | |
| 56 | value = strings.TrimSpace(value) |
| 57 | hyphenIndex := strings.Index(value, "-") |
| 58 | plusIndex := strings.Index(value, "+") |
| 59 | |
| 60 | if value == "" { |
| 61 | pr.Base = 0 |
| 62 | pr.Size = 0 |
| 63 | return nil |
| 64 | } |
| 65 | |
| 66 | var err error |
| 67 | var low, high int |
| 68 | var notation int |
| 69 | |
| 70 | if plusIndex == -1 && hyphenIndex == -1 { |
| 71 | notation |= SinglePortNotation |
| 72 | } |
| 73 | if hyphenIndex != -1 { |
| 74 | notation |= HyphenNotation |
| 75 | } |
| 76 | if plusIndex != -1 { |
| 77 | notation |= PlusNotation |
| 78 | } |
| 79 | |
| 80 | switch notation { |
| 81 | case SinglePortNotation: |
| 82 | var port int |
| 83 | port, err = strconv.Atoi(value) |
| 84 | if err != nil { |
| 85 | return err |
| 86 | } |
| 87 | low = port |
| 88 | high = port |
| 89 | case HyphenNotation: |
| 90 | low, err = strconv.Atoi(value[:hyphenIndex]) |
| 91 | if err != nil { |
| 92 | return err |
| 93 | } |
| 94 | high, err = strconv.Atoi(value[hyphenIndex+1:]) |
| 95 | if err != nil { |
| 96 | return err |
| 97 | } |
| 98 | case PlusNotation: |
| 99 | var offset int |
| 100 | low, err = strconv.Atoi(value[:plusIndex]) |
| 101 | if err != nil { |
| 102 | return err |
| 103 | } |
| 104 | offset, err = strconv.Atoi(value[plusIndex+1:]) |
| 105 | if err != nil { |
| 106 | return err |
| 107 | } |
| 108 | high = low + offset |
| 109 | default: |
| 110 | return fmt.Errorf("unable to parse port range: %s", value) |
| 111 | } |
| 112 | |
| 113 | if low > 65535 || high > 65535 { |
| 114 | return fmt.Errorf("the port range cannot be greater than 65535: %s", value) |
| 115 | } |
| 116 | |
| 117 | if high < low { |
| 118 | return fmt.Errorf("end port cannot be less than start port: %s", value) |
| 119 | } |
| 120 | |
| 121 | pr.Base = low |
| 122 | pr.Size = 1 + high - low |
| 123 | return nil |
| 124 | } |
| 125 | |
| 126 | // Type returns a descriptive string about this type. This is part of the |
| 127 | // pflag.Value interface. |
| 128 | func (*PortRange) Type() string { |
| 129 | return "portRange" |
| 130 | } |
| 131 | |
| 132 | // ParsePortRange parses a string of the form "min-max", inclusive at both |
| 133 | // ends, and initializs a new PortRange from it. |
| 134 | func ParsePortRange(value string) (*PortRange, error) { |
| 135 | pr := &PortRange{} |
| 136 | err := pr.Set(value) |
| 137 | if err != nil { |
| 138 | return nil, err |
| 139 | } |
| 140 | return pr, nil |
| 141 | } |
| 142 | |
| 143 | func ParsePortRangeOrDie(value string) *PortRange { |
| 144 | pr, err := ParsePortRange(value) |
| 145 | if err != nil { |
| 146 | panic(fmt.Sprintf("couldn't parse port range %q: %v", value, err)) |
| 147 | } |
| 148 | return pr |
| 149 | } |