ネットワークスキャンツールは、入力についてうるさくうるさいので、不適切な文字を含むIPv4アドレスまたは適切にフォーマットされていないIPv4アドレスを入力すると、すぐにクラッシュします。

IPv4アドレスは、ピリオドで区切られた4つの数字として記述された32ビットの数値アドレスです。各番号は0〜255にできます。

これらのクラッシュを回避するために、入力を事前検証するツールを作成する必要がありますが、特定のツールには注意が必要です。有効な形式はa.b.c.d、a、b、c、dのようになります。

• 先行ゼロなしの0自然数または自然数を指定できます。
• 0から255の間（両端を含む）でなければなりません。
• 必要がありませんのような特殊な記号含まれ+、-、,、などを。
• 10進数でなければなりません（基数10）

入力：文字列

出力：TruthyまたはFalseyの値（任意の値も受け入れられます）

テストケース：

Input            |  Output  |  Reason
                 |          |
- 1.160.10.240   |  true    |
- 192.001.32.47  |  false   |  (leading zeros present)
- 1.2.3.         |  false   |  (only three digits)
- 1.2.3          |  false   |  (only three digits)
- 0.00.10.255    |  false   |  (leading zeros present)
- 1.2.$.4        |  false   |  (only three digits and a special symbol present)
- 255.160.0.34   |  true    |
- .1.1.1         |  false   |  (only three digits)
- 1..1.1.1       |  false   |  (more than three periods)
- 1.1.1.-0       |  false   |  (special symbol present)
- .1.1.+1        |  false   |  (special symbol present)
- 1 1 1 1        |  false   |  (no periods)
- 1              |  false   |  (only one digit)
- 10.300.4.0     |  false   |  (value over 255)
- 10.4F.10.99    |  false   |  (invalid characters)
- fruit loops    |  false   |  (umm...)
- 1.2.3.4.5      |  false   |  (too many periods/numbers)
- 0.0.0.0        |  true    |
- 0.0 0.0.       |  false   |  (periods misplaced)
- 1.23..4        |  false   |  (a typo of 1.2.3.4)
- 1:1:1:1:1:1:1:1|  false   |  (an IPv6 address, not IPv4)

これはcode-golfなので、最少バイトが勝ちます！

ユーザーへの注意 -テストケースをさらに追加する場合は、（編集を提案することで）歓迎されます。しかし、テストケースが繰り返されないようにしてください！ありがとう

X86_64マシンコード： 18 16バイト

編集：この答えはまったく機能しません。

1. 私はinet_pton標準のCライブラリから使用しています。つまり、externが必要です。ただし、バイトカウントにはexternを含めませんでした。
2. 実際の住所の結果としてレッドゾーンを使用しましたが、レッドゾーンを使用することもできた関数を呼び出しました。幸いなことに私のマシンでは動作しませんが、奇妙な標準ライブラリビルドがそれを使用し、未定義の動作を引き起こす可能性があります。

そして、ええ、すべてはすでに書かれた関数によってほとんど行われています

とにかく、これは私が得たものです： 48 89 fe 6a 02 5f 48 8d 54 24 80 e9 00 00 00 00

アセンブリ：

section .text
    extern inet_pton
    global ipIsValid

ipIsValid:
    mov rsi, rdi
    ;mov rdi, 2 ; change to 10 for ipv6
    push 2
    pop rdi ; thank you peter
    lea rdx, [rsp - 128]
    jmp inet_pton

説明：

を見てくださいinet_pton(3)。文字列IPアドレスを取得し、それを使用できるバッファに入れますstruct sockaddr。3つの引数を取ります：アドレスファミリ（AF_INET（ipv4）、2、またはAF_INET6（ipv6）、10）、ipアドレスの文字列、および出力へのポインタ。成功した場合は1、無効なアドレスの場合は0、アドレスファミリがどちらAF_INETでもない場合は-1を返しますAF_INET6（定数を渡すため発生しません）。

したがって、結果を気にしないので、2番目の引数のレジスタに文字列を移動し、最初のレジスタを2に設定し、3番目のレジスタをレッドゾーン（スタックポインタの下128バイト）に設定します。その後、単純jmpにinet_pton呼び出し元にそれを返すことができます！

ケースをテストするために、このクイックテストプログラムを作成しました。

#include <stdio.h>
#include <arpa/inet.h>
#include <netinet/ip.h>

extern int ipIsValid(char *);

int main(){
    char *addresses[] = {
        "1.160.10.240",
        "192.001.32.47",
        "1.2.3.",
        "1.2.3",
        "0.00.10.255",
        "1.2.$.4",
        "255.160.0.34",
        ".1.1.1",
        "1..1.1.1",
        "1.1.1.-0",
        ".1.1.+1",
        "1 1 1 1",
        "1",
        "10.300.4.0",
        "10.4F.10.99",
        "fruit loops",
        "1.2.3.4.5",
        NULL
    };

    for(size_t i = 0; addresses[i] != NULL; ++i){
        printf("Address %s:\t%s\n", addresses[i],
            ipIsValid(addresses[i]) ? "true" : "false");
    }
    return 0;
}

でアセンブルしnasm -felf64 assembly.asm、でコンパイルするとgcc -no-pie test.c assembly.o、次のものが得られます。

Address 1.160.10.240:   true
Address 192.001.32.47:  false
Address 1.2.3.: false
Address 1.2.3:  false
Address 0.00.10.255:    false
Address 1.2.$.4:    false
Address 255.160.0.34:   true
Address .1.1.1: false
Address 1..1.1.1:   false
Address 1.1.1.-0:   false
Address .1.1.+1:    false
Address 1 1 1 1:    false
Address 1:  false
Address 10.300.4.0: false
Address 10.4F.10.99:    false
Address fruit loops:    false
Address 1.2.3.4.5:  false

呼び出し元が関数を渡すAF_INETかAF_INET6、関数に渡されることになっている場合、これをもっと小さくすることができます

Java（JDK）、63バイト

s->("."+s).matches("(\\.(25[0-5]|(2[0-4]|1\\d|[1-9])?\\d)){4}")

オンラインでお試しください！

クレジット

• -1バイトのおかげで Kevin Cruijssenに
• l4m2以前に失敗した場合を示します.1.1.1.1。

JavaScript（Node.js）、43バイト

x=>x.split`.`.map(t=>[t&255]==t&&[])==`,,,`

オンラインでお試しください！

JavaScript（Node.js）、46バイト

x=>x.split`.`.every(t=>k--&&[t&255]==t,k=4)*!k

オンラインでお試しください！

Arnauldのパーツを使用

JavaScript（Node.js）、54 53 51バイト

x=>x.split`.`.every(t=>k--*0+t<256&[~~t]==t,k=4)*!k

オンラインでお試しください！

-2B 0+t<256、パトリックステファンセンから-1B、入力を避けるための+ 1B1.1.1.1e-80

RegExpソリューション58 54バイト

s=>/^((2(?!5?[6-9])|1|(?!0\d))\d\d?\.?\b){4}$/.test(s)

Deadcodeに3バイトありがとう

PHP、39 36バイト

<?=+!!filter_var($argv[1],275,5**9);

オンラインでお試しください！

275は定数に似ています FILTER_VALIDATE_IP

定数の代わりに5 ** 9が使用されています FILTER_FLAG_IPV4ます。5**9 & FILTER_FLAG_IPV4Benoit Esnardが指摘したように、これはPHPがバックグラウンドで行うこととまったく同じであるため、これは十分です。

ここで、filter_var有効なIPv4アドレスである場合は最初の引数を返し、そうでない場合はfalseを返します。では+!!、チャレンジに必要な出力を生成します。

PHP、36バイト

echo(ip2long($argv[1])===false?0:1);

ip2longはよく知られた組み込み関数です。

Perl 6の、22 21 20バイト

Phil Hのおかげで-1バイト

{?/^@(^256)**4%\.$/}

オンラインでお試しください！

説明

{                  }  # Anonymous Block
  /               /   # Regex match
   ^             $    # Anchor to start/end
    @(    )           # Interpolate
      ^256            #   range 0..255,
                      #   effectively like (0|1|2|...|255)
           **4        # Repeated four times
              %\.     # Separated by dot
 ?                    # Convert match result to Bool

05AB1E、26 24 23 22 23 バイト

'.¡©g4Q₅Ý®å`®1šDïþJsJQP

@Emignaのおかげで-1バイト。
テストケースをバグ修正するための+1バイトは1.1.1.1E1、誤った結果を誤って返します。

オンラインそれを試してみたり、すべてのテストケースを確認してください。

説明：

'.¡              '# Split the (implicit) input by "."
   ©              # Save it in the register (without popping)
    g4Q           # Check that there are exactly 4 numbers
    ₅Ý®å          # Check for each of the numbers that they are in the range [0,255],
        `         # and push the result for each number separated onto the stack
    ®1šDïþJsJQ    # Check that each number does NOT start with a "0" (excluding 0s itself),
                  # and that they consist of digits only
              P   # Check if all values on the stack are truthy (and output implicitly)

PowerShell、59 51 49バイト

-8バイト、@ AdmBorkBorkに感謝

-2バイト、trueまたは作成者がfalse許可

try{"$args"-eq[IPAddress]::Parse($args)}catch{!1}

テストスクリプト：

$f = {

try{"$args"-eq[IPAddress]::Parse($args)}catch{!1}

}

@(
    ,("1.160.10.240" , $true)
    ,("192.001.32.47" , $false)
    ,("1.2.3." , $false)
    ,("1.2.3" , $false)
    ,("0.00.10.255" , $false)
    ,("192.168.1.1" , $true)
    ,("1.2.$.4" , $false)
    ,("255.160.0.34" , $true)
    ,(".1.1.1" , $false)
    ,("1..1.1.1" , $false)
    ,("1.1.1.-0" , $false)
    ,("1.1.1.+1" , $false)
    ,("1 1 1 1" , $false)
    ,("1"            ,$false)
    ,("10.300.4.0"   ,$false)
    ,("10.4F.10.99"  ,$false)
    ,("fruit loops"  ,$false)
    ,("1.2.3.4.5"    ,$false)

) | % {
    $s,$expected = $_
    $result = &$f $s
    "$($result-eq$expected): $result : $s"
}

出力：

True: True : 1.160.10.240
True: False : 192.001.32.47
True: False : 1.2.3.
True: False : 1.2.3
True: False : 0.00.10.255
True: True : 192.168.1.1
True: False : 1.2.$.4
True: True : 255.160.0.34
True: False : .1.1.1
True: False : 1..1.1.1
True: False : 1.1.1.-0
True: False : 1.1.1.+1
True: False : 1 1 1 1
True: False : 1
True: False : 10.300.4.0
True: False : 10.4F.10.99
True: False : fruit loops
True: False : 1.2.3.4.5

説明：

スクリプトは、引数文字列を解析して、.NETオブジェクトIPAddressを構築しようとします。

• 作成され、引数文字列が（による正規化されたアドレス）の文字列表現と等しい$true場合に返しますobjectobjectobject.toString()
• $falseそうでなければ戻る

PowerShell、59 56 54バイト、「。NET libを使用しない」代替

-3バイト、trueまたは作成者がfalse許可

-2バイト。クールな正規表現の@ Deadcodeに感謝します。

".$args"-match'^(\.(2(?!5?[6-9])|1|(?!0\B))\d\d?){4}$'

オンラインでお試しください！

元の正規表現をありがとう@ OlivierGrégoire

C（gcc） / POSIX、26バイト

f(s){s=inet_pton(2,s,&s);}

オンラインでお試しください！

TIOでは64ビットコードとして機能しますがsizeof(int) == sizeof(char*)、他のプラットフォームではおそらくそれが必要です。

PHP 7+, 37 35 32 bytes

This uses the builtin function filter_var, to validate that it is an IPv4 address.

For it to work, you need to pass the key i over a GET request.

<?=filter_var($_GET[i],275,5**9);

Will output nothing (for a falsy result) or the IP (for a truthy result), depending on the result.

You can try this on: http://sandbox.onlinephpfunctions.com/code/639c22281ea3ba753cf7431281486d8e6e66f68e http://sandbox.onlinephpfunctions.com/code/ff6aaeb2b2d0e0ac43f48125de0549320bc071b4

This uses the following values directly:

• 275 = FILTER_VALIDATE_IP
• 1<<20 = 1048576 = FILTER_FLAG_IPV4
• 5**9 = 1953125 (which has the required bit as "1", for 1048576)

Thank you to Benoit Esnard for this tip that saved me 1 byte!

Thank you to Titus for reminding me of the changes to the challenge.

I've looked into using the function ip2long, but it works with non-complete IP addresses.

Non-complete IPv4 addresses are considered invalid in this challenge.

If they were allowed, this would be the final code (only for PHP 5.2.10):

<?=ip2long($_GET[i]);

Currently, it isn't explicit in the documentation that this will stop working (when passed an incomplete ip) with newer PHP versions.

After testing, confirmed that that was the case.

Thanks to nwellnhof for the tip!

Python 3: 81 78 70 69 66 bytes

['%d.%d.%d.%d'%(*x.to_bytes(4,'big'),)for x in range(16**8)].count

Loop over all possible IPv4 addresses, get the string representation and compare it to the input. It uh... takes a while to run.

EDIT: Removed 3 bytes by switching from full program to anonymous function.

EDIT2: Removed 8 bytes with help from xnor

EDIT3: Removed 1 byte by using an unpacked map instead of list comprehension

EDIT4: Removed 3 bytes by using list comprehension instead of the ipaddress module

C# (Visual C# Interactive Compiler), 84 79 65 bytes

s=>s.Split('.').Sum(t=>byte.TryParse(t,out var b)&t==b+""?1:5)==4

Try it online!

-5 and -14 bytes saved thanks to @dana!

# C# (Visual C# Interactive Compiler), 61 bytes

s=>s.Count(c=>c==46)==3&IPAddress.TryParse(s,out IPAddress i)

Try it online!

This is a work in progress. The code use System.Net (+17 bytes if you count it). if you wonder why I count and parse:

The limitation with IPAddress.TryParse method is that it verifies if a string could be converted to IP address, thus if it is supplied with a string value like "5", it consider it as "0.0.0.5".

source

As @milk said in comment, it will indeed fail on leading zeroes. So, the 61 bytes one is not working.

Python 2, 85 82 81 bytes

-1 byte thanks to Kevin Cruijssen

from ipaddress import*
I=input()
try:r=I==str(IPv4Address(I))
except:r=0
print~~r

Try it online!

113 byte answer is deleted as it fails for 1.1.1.1e-80

Japt, 17 15 bytes

q.
ʶ4«Uk#ÿòs)Ê

Try it or run all test cases or verify additional test cases from challenge comments

Explanation

We split to an array on ., check that the length of that array is equal to 4 AND that the length when all elements in the range ["0","255"] are removed from it is falsey (0).

                 :Implicit input of string U
q.               :Split on "."
\n               :Reassign resulting array to U
Ê                :Length of U
 ¶4              :Equals 4?
   «             :&&!
    Uk           :Remove from U
      #ÿ         :  255
        ò        :  Range [0,255]
         s       :  Convert each to a string
          )      :End removal
           Ê     :Length of resulting array

Mathematica, 39 31 bytes

Original version:

¬FailureQ[Interpreter["IPAddress"][#]]&

Modified version (thanks to Misha Lavrov)

 AtomQ@*Interpreter["IPAddress"]

which returns True if the input is a valid IP address (try it).

In case you insist on getting 1 and 0 instead, then an additional 7 bytes would be necessary:

Boole/@AtomQ@*Interpreter["IPAddress"]

JavaScript (ES6), 49 bytes

Returns a Boolean value.

s=>[0,1,2,3].map(i=>s.split`.`[i]&255).join`.`==s

Try it online!

Python 2, 93 89 67 53 bytes

[i==`int(i)&255`for i in input().split('.')]!=[1]*4>_

Try it online!

Thanks to Dennis for shaving another 14 bytes on the internal comparisons and exit code.

Special thanks to Jonathan Allan for shaving 22 bytes & a logic fix! Pesky try/except begone!

Taking properly formatted strings instead of raw bytes shaves off 4 bytes, thanks Jo King.

sfk, 176 bytes

* was originally Bash + SFK but TIO has since added a proper SFK wrapper

xex -i "_[lstart][1.3 digits].[1.3 digits].[1.3 digits].[1.3 digits][lend]_[part2]\n[part4]\n[part6]\n[part8]_" +xed _[lstart]0[digit]_999_ +hex +linelen +filt -+1 -+2 +linelen

Try it online!

Python3 Bash* 60

*Also other shells. Any one for which the truthy/falsy test passes on a program exit code

read I
python3 -c "from ipaddress import*;IPv4Address('$I')"

Explanation

The trouble with a pure Python solutions is that a program crashing is considered indeterminate. We could use a "lot" of code to convert an exception into a proper truthy/fasly value. However, at some point the Python interpreter handles this uncaught exception and returns a non-zero exit code. For the low-low cost of changing languages to your favourite Unix shell, we can save quite a bit of code!

Of course, this is vulnerable to injection attacks... Inputs such as 1.1.1.1'); print('Doing Something Evil are an unmitigated threat!

ECMAScript pure regex, 41 bytes

^((2(?!5?[6-9])|1|(?!0\B))\d\d?\.?\b){4}$

Try it online!
Try it on regex101

I think the logic in this regex speaks for itself, so I will merely pretty-print but not comment it:

^
(
    (
        2(?!5?[6-9])
    |
        1
    |
        (?!0\B)
    )
    \d\d?
    \.?\b
){4}
$

This can be used to shave 2 bytes off the following other answers:

• Olivier Grégoire (Java (JDK))
• l4m2 (JavaScript (Node.js))
• mazzy (PowerShell)
• Kevin Cruijssen (Retina)

Here is an alternative version that allows leading zeros, but does so consistently (octets may be represented by a maximum of 3 decimal digits):

^((2(?!5?[6-9])|1|0?)\d\d?\.?\b){4}$

Or allow any number of leading zeros:

^(0*(2(?!5?[6-9])|1?)\d\d?\.?\b){4}$

Red, 106 bytes

func[s][if error? try[t: load s][return off]if 4 <> length? t[return off]s =
form as-ipv4 t/1 t/2 t/3 t/4]

Try it online!

Returnd true or false

Explanation:

f: func [ s ] [
    if error? try [                  ; checks if the execution of the next block result in an error
        t: load s                    ; loading a string separated by '.' gives a tuple   
    ] [                              ; each part of which must be in the range 0..255
        return off                   ; if there's an error, return 'false' 
    ]
    if 4 <> length? t [              ; if the tuple doesn't have exactly 4 parts
        return off                   ; return 'false'  
    ]
    s = form as-ipv4 t/1 t/2 t/3 t/4 ; is the input equal to its parts converted to an IP adress
]

Stax, 14 bytes

∞n·Θ3ª&JH‼∙*~Γ

Run and debug it

Unpacked, ungolfed, and commented, it looks like this.

VB      constant 256
r       [0 .. 255]
'|*     coerce and string-join with "|"; i.e. "0|1|2|3 ... 254|255"
:{      parenthesize to "(0|1|2|3 ... 254|255)"
]4*     make 4-length array of number pattern
.\.*    string join with "\\."; this forms the complete regex
|Q      is the input a complete match for the regex?

Run this one

Python 3, 109 93 bytes

import re
lambda x:bool(re.match(r'^((25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)(\.(?!$)|$)){4}$',x))

Explanation

Each octet can be 0 - 255 :

• starts with 25 and having 0-5 as last digit
• start with 2, has 0-4 as second digit and any digit at the end
• starts with 1, and 00 - 99 as rest digits
• has only 2 digits - 1-9 being the first one and any digit thereafter
• or just a single digit

An octet can end with a (.) or just end, with the condition that it cannot do both , the negative lookahead (?!$) takes care of this case

Thanks @Zachary for making me realize I can discard spaces (since it is code golf)
Thanks @DLosc for the improvements and making me realize my mistake, its been corrected now.

Bash, 30 bytes

ipcalc -c `cat`;echo $(($?^1))

Try it online!

Charcoal, 45 21 bytes

Ｉ∧⁼№θ.³¬Φ⪪θ.¬№Ｅ²⁵⁶Ｉλι

Try it online! Link is to verbose version of code. Edit: Saved 24 bytes by porting @Shaggy's Japt answer. Explanation:

    θ                   Input string
   №                    Count occurrences of
     .                  Literal `.`
  ⁼                     Equal to
      ³                 Literal 3
 ∧                      Logical And
       ¬                Logical Not
          θ             Input string
         ⪪              Split on
           .            Literal `.`
        Φ               Filter by
            ¬           Logical Not
               ²⁵⁶      Literal 256
              Ｅ         Map over implicit range
                   λ    Map value
                  Ｉ     Cast to string
             №          Count occurrences of
                    ι   Filter value
Ｉ                       Cast to string
                        Implicitly print

Retina, 46 44 bytes

^
.
^(\.(25[0-5]|(2[0-4]|1\d|[1-9])?\d)){4}$

Port of @OlivierGrégoire's Java answer, so make sure to upvote him!
-2 bytes thanks to @Neil.

Try it online.

Explanation:

^
.                           # Prepend a dot "." before the (implicit) input
^...$                       # Check if the entire string matches the following regex
                            # exactly, resulting in 1/0 as truthy/falsey:
 (                          #  Open a capture group
  \.                        #   A dot "."
    (25[0-5]                #   Followed by a number in the range [250,255]
    |(2[0-4]|         ) \d) #   or by a number in the range [200,249]
    |(      |1\d|     ) \d) #   or by a number in the range [100,199]
    |(          |[1-9]) \d) #   or by a number in the range [10,99]
    |(                )?\d) #   or by a number in the range [0,9]
 )                          #  Close capture group
  {4}                       #  This capture group should match 4 times after each other

Jelly, 11 bytes

⁹ḶṾ€ṗ4j€”.ċ

A monadic link accepting a list of characters which yields $1$ if it's a valid address and $0$ otherwise. Builds a list of all $256^4=4294967296$ addresses and then counts the number of occurrences of the input therein.

Here's similar @ Try it online! that uses $16$ (⁴) rather than $256$ (⁹), since the method is so inefficient!

How?

⁹ḶṾ€ṗ4j€”.ċ - Link: list of characters, S
⁹           - literal 256
 Ḷ          - lowered range = [0,1,2,...,254,255]
  Ṿ€        - unevaluate €ach = ['0','1',...,['2','5','4'],['2','5','5']]
    ṗ4      - 4th Cartesian power = ALL 256^4 lists of 4 of them
            -               (e.g.: ['0',['2','5','5'],'9',['1','0']])
        ”.  - literal '.' character
      j€    - join for €ach (e.g. ['0','.','2','5','5','.','9','.','1','0'] = "0.255.9.10")
          ċ - count occurrences of right (S) in left (that big list)

Retina, 42 41 bytes

~(K`

255*
["^(("|'|]")\.?\b){4}$"L$`
$.`

Try it online! Based on a previous version of @nwellnhof's Perl 6 answer, but 1 byte saved by stealing the \.?\b trick from @Deadcode's answer. Explanation:

K`

Clear the work area.

255*

Insert 255 characters.

["^(("|'|]")\.?\b){4}$"L$`
$.`

Generate the range 0..255 separated with |s, prefixed with ^((, and suffixed with )\.?\b){4}$, thus building the regular expression ^((0|1|...255)\.?\b){4}$.

~(

Evaluate that on the original input.

Pip, 25 16 bytes

a~=X,256RL4J"\."

Takes the candidate IP address as a command-line argument. Try it online! or Verify all test cases

Explanation

Regex solution, essentially a port of recursive's Stax answer.

                  a is 1st cmdline arg (implicit)
    ,256          Range(256), i.e. [0 1 2 ... 255]
   X              To regex: creates a regex that matches any item from that list
                  i.e. essentially `(0|1|2|...|255)`
        RL4       Create a list with 4 copies of that regex
           J"\."  Join on this string
 ~=               Regex full-match
a                 against the input

JavaScript, 89 bytes

(_,r=`(${[...Array(256).keys()].join`|`})`)=>RegExp(`^${(r+'\\.').repeat(3)+r}$`).test(_)

Try it online!

Create RegExp capture groups from indexes of an array having length 256 for range 0-255 joined with | and followed by escaped . character (^(0|1...|255)\.(0|1...|255)\.(0|1...|255)\.(0|1...|255)$) repeated 3 times closing with joined array followed by $ to match end of string, return true or false result of input passed to RegExp.prototype.test().