测试cidr表示的网络是否与另一个网络重叠 [英] Testing if a network in cidr notation overlaps another network
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问题描述
我正在寻找一种有效地测试一个cidr标记的网络是否重叠的php算法。
I'm searching for a php algorithm that efficiently test if one cidr notated network overlaps another.
基本上，我遇到以下情况：
Basically I have the following situation:
cidr地址数组：
$cidrNetworks = array(
'192.168.10.0/24',
'10.10.0.30/20',
etc.
);
我有一个将网络添加到阵列中的方法，但是当网络出现时，该方法应该引发异常添加了与阵列中已经就绪的网络重叠的数据。
I have a method that adds networks to the array, but this method should throw an exception when a network is added that overlaps with a network allready in the array.
就是这样。如果添加了192.168.10.0/25，则应该引发异常。
So ie. if 192.168.10.0/25 is added an exception should be thrown.
是否有人/知道/想到了一种可以有效地进行测试的方法？
Does anyone have/know/"can think of" an method to test this efficiently?
推荐答案
此处是先前在聊天中讨论的类的更新版本。它可以满足您的要求以及其他许多有用的功能。
Here is an updated version of the class previously discussed in chat. It can do what you require, as well as many other useful things.
<?php
class IPv4Subnet implements ArrayAccess, Iterator {
/*
* Address format constants
*/
const ADDRESS_BINARY = 0x01;
const ADDRESS_INT = 0x02;
const ADDRESS_DOTDEC = 0x04;
const ADDRESS_SUBNET = 0x08;
/*
* Constants to control whether getHosts() returns the network/broadcast addresses
*/
const HOSTS_WITH_NETWORK = 0x10;
const HOSTS_WITH_BROADCAST = 0x20;
const HOSTS_ALL = 0x30;
/*
* Properties to store base address and subnet mask as binary strings
*/
protected $address;
protected $mask;
/*
* Counter to track the current iteration offset
*/
private $iteratorOffset = 0;
/*
* Array to hold values retrieved via ArrayAccess
*/
private $arrayAccessObjects = array();
/*
* Helper methods
*/
private function longToBinary ($long) {
return pack('N', $long);
}
private function longToDottedDecimal ($long) {
return ($long >> 24 & 0xFF).'.'.($long >> 16 & 0xFF).'.'.($long >> 8 & 0xFF).'.'.($long & 0xFF);
}
private function longToByteArray ($long) {
return array(
$long >> 24 & 0xFF,
$long >> 16 & 0xFF,
$long >> 8 & 0xFF,
$long & 0xFF
);
}
private function longToSubnet ($long) {
if (!isset($this->arrayAccessObjects[$long])) {
$this->arrayAccessObjects[$long] = new self($long);
}
return $this->arrayAccessObjects[$long];
}
private function binaryToLong ($binary) {
return current(unpack('N', $binary));
}
private function binaryToDottedDecimal ($binary) {
return implode('.', unpack('C*', $binary));
}
private function binaryToX ($binary, $mode) {
if ($mode & self::ADDRESS_BINARY) {
$result = $binary;
} else if ($mode & self::ADDRESS_INT) {
$result = $this->binaryToLong($binary);
} else if ($mode & self::ADDRESS_DOTDEC) {
$result = $this->binaryToDottedDecimal($binary);
} else {
$result = $this->longToSubnet($this->binaryToLong($binary));
}
return $result;
}
private function byteArrayToLong($bytes) {
return ($bytes[0] << 24) | ($bytes[1] << 16) | ($bytes[2] << 8) | $bytes[3];
}
private function byteArrayToBinary($bytes) {
return pack('C*', $bytes[0], $bytes[1], $bytes[2], $bytes[3]);
}
private function normaliseComparisonSubject (&$subject) {
if (!is_object($subject)) {
$subject = new self($subject);
}
if (!($subject instanceof self)) {
throw new InvalidArgumentException('Subject must be an instance of IPv4Subnet');
}
}
private function validateOctetArray (&$octets) {
foreach ($octets as &$octet) {
$octet = (int) $octet;
if ($octet < 0 || $octet > 255) {
return FALSE;
}
}
return TRUE;
}
/*
* Constructor
*/
public function __construct ($address = NULL, $mask = NULL) {
if ($address === NULL || (is_string($address) && trim($address) === '')) {
$address = array(0, 0, 0, 0);
} else if (is_int($address)) {
$address = $this->longToByteArray($address);
} else if (is_string($address)) {
$parts = preg_split('#\s*/\s*#', trim($address), -1, PREG_SPLIT_NO_EMPTY);
if (count($parts) > 2) {
throw new InvalidArgumentException('No usable IP address supplied: Syntax error');
} else if ($parts[0] === '') {
throw new InvalidArgumentException('No usable IP address supplied: IP address empty');
}
if (!empty($parts[1]) && !isset($mask)) {
$mask = $parts[1];
}
$address = preg_split('#\s*\.\s*#', $parts[0], -1, PREG_SPLIT_NO_EMPTY);
} else if (is_array($address)) {
$address = array_values($address);
} else {
throw new InvalidArgumentException('No usable IP address supplied: Value must be a string or an integer');
}
$suppliedAddressOctets = count($address);
$address += array(0, 0, 0, 0);
if ($suppliedAddressOctets > 4) {
throw new InvalidArgumentException('No usable IP address supplied: IP address has more than 4 octets');
} else if (!$this->validateOctetArray($address)) {
throw new InvalidArgumentException('No usable IP address supplied: At least one octet value outside acceptable range 0 - 255');
}
if ($mask === NULL) {
$mask = array_pad(array(), $suppliedAddressOctets, 255) + array(0, 0, 0, 0);
} else if (is_int($mask)) {
$mask = $this->longToByteArray($mask);
} else if (is_string($mask)) {
$mask = preg_split('#\s*\.\s*#', trim($mask), -1, PREG_SPLIT_NO_EMPTY);
switch (count($mask)) {
case 1: // CIDR
$cidr = (int) $mask[0];
if ($cidr === 0) {
// Shifting 32 bits on a 32 bit system doesn't work, so treat this as a special case
$mask = array(0, 0, 0, 0);
} else if ($cidr <= 32) {
// This looks odd, but it's the nicest way I have found to get the 32 least significant bits set in a
// way that works on both 32 and 64 bit platforms
$base = ~((~0 << 16) << 16);
$mask = $this->longToByteArray($base << (32 - $cidr));
} else {
throw new InvalidArgumentException('Supplied mask invalid: CIDR outside acceptable range 0 - 32');
}
break;
case 4: break; // Dotted decimal
default: throw new InvalidArgumentException('Supplied mask invalid: Must be either a full dotted-decimal or a CIDR');
}
} else if (is_array($mask)) {
$mask = array_values($mask);
} else {
throw new InvalidArgumentException('Supplied mask invalid: Type invalid');
}
if (!$this->validateOctetArray($mask)) {
throw new InvalidArgumentException('Supplied mask invalid: At least one octet value outside acceptable range 0 - 255');
}
// Check bits are contiguous from left
// TODO: Improve this mechanism
$asciiBits = sprintf('%032b', $this->byteArrayToLong($mask));
if (strpos(rtrim($asciiBits, '0'), '0') !== FALSE) {
throw new InvalidArgumentException('Supplied mask invalid: Set bits are not contiguous from the most significant bit');
}
$this->mask = $this->byteArrayToBinary($mask);
$this->address = $this->byteArrayToBinary($address) & $this->mask;
}
/*
* ArrayAccess interface methods (read only)
*/
public function offsetExists ($offset) {
if ($offset === 'network' || $offset === 'broadcast') {
return TRUE;
}
$offset = filter_var($offset, FILTER_VALIDATE_INT);
if ($offset === FALSE || $offset < 0) {
return FALSE;
}
return $offset < $this->getHostsCount();
}
public function offsetGet ($offset) {
if (!$this->offsetExists($offset)) {
return NULL;
}
if ($offset === 'network') {
$address = $this->getNetworkAddress(self::ADDRESS_INT);
} else if ($offset === 'broadcast') {
$address = $this->getBroadcastAddress(self::ADDRESS_INT);
} else {
// How much the address needs to be adjusted by to account for network address
$adjustment = (int) ($this->getHostsCount() > 2);
$address = $this->binaryToLong($this->address) + $offset + $adjustment;
}
return $this->longToSubnet($address);
}
public function offsetSet ($offset, $value) {}
public function offsetUnset ($offset) {}
/*
* Iterator interface methods
*/
public function current () {
return $this->offsetGet($this->iteratorOffset);
}
public function key () {
return $this->iteratorOffset;
}
public function next () {
$this->iteratorOffset++;
}
public function rewind () {
$this->iteratorOffset = 0;
}
public function valid () {
return $this->iteratorOffset < $this->getHostsCount();
}
/*
* Data access methods
*/
public function getHosts ($mode = self::ADDRESS_SUBNET) {
// Parse flags and initialise vars
$bin = (bool) ($mode & self::ADDRESS_BINARY);
$int = (bool) ($mode & self::ADDRESS_INT);
$dd = (bool) ($mode & self::ADDRESS_DOTDEC);
$base = $this->binaryToLong($this->address);
$mask = $this->binaryToLong($this->mask);
$hasNwBc = !($mask & 0x03);
$result = array();
// Get network address if requested
if (($mode & self::HOSTS_WITH_NETWORK) && $hasNwBc) {
$result[] = $base;
}
// Get hosts
for ($current = $hasNwBc ? $base + 1 : $base; ($current & $mask) === $base; $current++) {
$result[] = $current;
}
// Remove broadcast address if present and not requested
if ($hasNwBc && !($mode & self::HOSTS_WITH_BROADCAST)) {
array_pop($result);
}
// Convert to the correct type
if ($bin) {
$result = array_map(array($this, 'longToBinary'), $result);
} else if ($dd) {
$result = array_map(array($this, 'longToDottedDecimal'), $result);
} else if (!$int) {
$result = array_map(array($this, 'longToSubnet'), $result);
}
return $result;
}
public function getHostsCount () {
$count = $this->getBroadcastAddress(self::ADDRESS_INT) - $this->getNetworkAddress(self::ADDRESS_INT);
return $count > 2 ? $count - 1 : $count + 1; // Adjust return value to exclude network/broadcast addresses
}
public function getNetworkAddress ($mode = self::ADDRESS_SUBNET) {
return $this->binaryToX($this->address, $mode);
}
public function getBroadcastAddress ($mode = self::ADDRESS_SUBNET) {
return $this->binaryToX($this->address | ~$this->mask, $mode);
}
public function getMask ($mode = self::ADDRESS_DOTDEC) {
return $this->binaryToX($this->mask, $mode);
}
/*
* Stringify methods
*/
public function __toString () {
if ($this->getHostsCount() === 1) {
$result = $this->toDottedDecimal();
} else {
$result = $this->toCIDR();
}
return $result;
}
public function toDottedDecimal () {
$result = $this->getNetworkAddress(self::ADDRESS_DOTDEC);
if ($this->mask !== "\xFF\xFF\xFF\xFF") {
$result .= '/'.$this->getMask(self::ADDRESS_DOTDEC);
}
return $result;
}
public function toCIDR () {
$address = $this->getNetworkAddress(self::ADDRESS_DOTDEC);
$cidr = strlen(trim(sprintf('%b', $this->getMask(self::ADDRESS_INT)), '0')); // TODO: Improve this mechanism
return $address.'/'.$cidr;
}
/*
* Comparison methods
*/
public function contains ($subject) {
$this->normaliseComparisonSubject($subject);
$subjectAddress = $subject->getNetworkAddress(self::ADDRESS_BINARY);
$subjectMask = $subject->getMask(self::ADDRESS_BINARY);
return $this->mask !== $subjectMask && ($this->mask | ($this->mask ^ $subjectMask)) !== $this->mask && ($subjectAddress & $this->mask) === $this->address;
}
public function within ($subject) {
$this->normaliseComparisonSubject($subject);
$subjectAddress = $subject->getNetworkAddress(self::ADDRESS_BINARY);
$subjectMask = $subject->getMask(self::ADDRESS_BINARY);
return $this->mask !== $subjectMask && ($this->mask | ($this->mask ^ $subjectMask)) === $this->mask && ($this->address & $subjectMask) === $subjectAddress;
}
public function equalTo ($subject) {
$this->normaliseComparisonSubject($subject);
return $this->address === $subject->getNetworkAddress(self::ADDRESS_BINARY) && $this->mask === $subject->getMask(self::ADDRESS_BINARY);
}
public function intersect ($subject) {
$this->normaliseComparisonSubject($subject);
return $this->equalTo($subject) || $this->contains($subject) || $this->within($subject);
}
}
为了做自己想做的事，该类提供了4种方法：
In order to do what you desire, the class provides 4 methods:
contains()
within()
equalTo()
intersect()
这些示例的用法：
// Also accepts dotted decimal mask. The mask may also be passed to the second
// argument. Any valid combination of dotted decimal, CIDR and integers will be
// accepted
$subnet = new IPv4Subnet('192.168.0.0/24');
// These methods will accept a string or another instance
var_dump($subnet->contains('192.168.0.1')); //TRUE
var_dump($subnet->contains('192.168.1.1')); //FALSE
var_dump($subnet->contains('192.168.0.0/16')); //FALSE
var_dump($subnet->within('192.168.0.0/16')); //TRUE
// ...hopefully you get the picture. intersect() returns TRUE if any of the
// other three match.
该类还实现了 Iterator 接口，允许您迭代子网中的所有地址。迭代器不包括可以分别检索的网络和广播地址。
The class also implements the Iterator interface, allowing you to iterate over all the addresses in a subnet. The iterator excludes the network and broadcast addresses, which can be retrieved separately.
示例：
$subnet = new IPv4Subnet('192.168.0.0/28');
echo "Network: ", $subnet->getNetworkAddress(),
"; Broadcast: ", $subnet->getBroadcastAddress(),
"\nHosts:\n";
foreach ($subnet as $host) {
echo $host, "\n";
}
该类还实现了 ArrayAccess ，允许您将其视为数组：
The class also implements ArrayAccess, allowing you to treat it as an array:
$subnet = new IPv4Subnet('192.168.0.0/28');
echo $subnet['network'], "\n"; // 192.168.0.0
echo $subnet[0], "\n"; // 192.168.0.1
// ...
echo $subnet[13], "\n"; // 192.168.0.14
echo $subnet['broadcast'], "\n"; // 192.168.0.15
NB：访问子网主机地址的迭代器/数组方法将返回另一个 IPv4Subnet 对象。该类实现 __ toString（），如果它表示一个地址，则将IP地址返回为点分十进制；如果它表示多个地址，则将返回CIDR。通过调用相关的 get *（）方法并传递所需的标志，可以直接以字符串或整数形式访问数据（请参见
NB: The iterator/array methods of accessing the subnet's host addresses will return another IPv4Subnet object. The class implements __toString(), which will return the IP address as a dotted decimal if it represents a single address, or the CIDR if it represents more than one. The data can be accessed directly as a string or an integer by calling the relevant get*() method and passing the desired flag(s) (see constants defined at the top of the class).
所有操作都是32位和64位安全的。兼容性应该（尽管未经彻底测试）5.2 +
All operations are 32- and 64-bit safe. Compatibility should be (although not thoroughly tested) 5.2+
为了完整起见，我想您的用例将按照以下方式实现：
For completeness, I imagine your use case would be implemented something along these lines:
public function addSubnet ($newSubnet) {
$newSubnet = new IPv4Subnet($newSubnet);
foreach ($this->subnets as &$existingSubnet) {
if ($existingSubnet->contains($newSubnet)) {
throw new Exception('Subnet already added');
} else if ($existingSubnet->within($newSubnet)) {
$existingSubnet = $newSubnet;
return;
}
}
$this->subnets[] = $newSubnet;
}
这篇关于测试cidr表示的网络是否与另一个网络重叠的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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