Embedding Strategies

When using version 4 and version 6 addresses interchangeably (via the Multi class), version 4 addresses are embedded into version 6 addresses so that both versions are stored as 16-byte binary sequences.

Unfortunately there are several different strategies for embedding a version 4 address into version 6, so this library offers various strategy implementations for the main three:

Each embedding strategy implements the Darsyn\IP\Strategy\EmbeddingStrategyInterface which defines methods to:

• Detect whether a version 4 address is embedded into a version 6 address,
• Extracting a version 4 address from a version 6 address, and
• Packing a version 4 address into a version 6 address according to the given strategy.

Specifying a Strategy

This library will automatically use the IPv4-mapped embedding strategy unless otherwise instructed.

An embedding strategy can be specified globally or on a per-instance basis.

<?php
use Darsyn\IP\Strategy;
use Darsyn\IP\Version\Multi as IP;

// Set the IPv4-compatible embedding strategy to be used globally.
IP::setDefaultEmbeddingStrategy(new Strategy\Compatible);

// But for this specific instance use the 6to4-derived embedding strategy.
$ip = IP::factory('127.0.0.1', new Strategy\Derived);