# ol.clave.crypto.impl.parse-ip

Parse a string representation of an IPv4 or IPv6 address into an InetAddress instance.

Unlike `InetAddress/getByName`, the functions in this namespace never cause
DNS services to be accessed. This avoids potentially blocking/side-effecting
network calls that can occur when using the JDK’s built-in methods to parse IP
addresses.

This implementation is inspired by Google Guava’s InetAddresses class, which
provides similar functionality in Java. This code focuses on strict validation
of IP address formats according to relevant RFCs.

Features:
- Non-blocking IP address parsing with pure functions
- Strict RFC-compliant validation
- Support for all IPv4 formats
- Support for all IPv6 formats (including compressed notation and embedded IPv4)
- Support for IPv6 scope identifiers

The main entry point is `parse-ip`, which takes a string and returns an
InetAddress instance or nil if the input is an invalid ip address literal.

## ip-string->bytes

```clojure
(ip-string->bytes ip-string)
```

Convert an IP string to bytes. Returns [byte-array scope-id] or nil if invalid.

[source,window=_blank](https://github.com/outskirtslabs/clave/blob/main/src/ol/clave/crypto/impl/parse_ip.clj#L204-L225)

---

## bytes->inet-address

```clojure
(bytes->inet-address addr)
(bytes->inet-address addr scope)
```

Convert a byte array into an InetAddress.

Args:
  addr: the raw 4-byte or 16-byte IP address in big-endian order
  scope: optional scope identifier for IPv6 addresses

[source,window=_blank](https://github.com/outskirtslabs/clave/blob/main/src/ol/clave/crypto/impl/parse_ip.clj#L235-L260)

---

## from-string

```clojure
(from-string ip-string)
```

Returns the InetAddress having the given string representation or nil otherwise.

This function parses IP address strings without performing DNS lookups, making it
suitable for environments where DNS lookups would cause unwanted blocking or side effects.

It supports:
- IPv4 addresses in dotted decimal format (e.g., "192.168.1.1")
- IPv6 addresses in hex format with optional compression (e.g., "2001:db8::1")
- IPv6 addresses with scope IDs (e.g., "fe80::1%eth0" or "fe80::1%1")
- IPv6 addresses with embedded IPv4 (e.g., "::ffff:192.168.1.1")

If the input is already an InetAddress, it is returned unchanged.

Args:
  ip-string: A string representing an IP address or an InetAddress
             
Returns:
  An InetAddress object, or nil if the input couldn’t be parsed

[source,window=_blank](https://github.com/outskirtslabs/clave/blob/main/src/ol/clave/crypto/impl/parse_ip.clj#L262-L294)