Fix IP Address Conversion Functions for Proper IPv4-Mapped IPv6 Format #641
Description
Desciption
The current implementation of ToIP6 and ToIP4 functions does not properly convert between IPv4 and IPv4-mapped IPv6 address formats. The IPv4-mapped IPv6 addresses should follow the format ::ffff:a.b.c.d where a.b.c.d is the IPv4 address in dotted-decimal notation.
Current Behavior
- ToIP6 converts IPv4 addresses to a format that is not properly recognized as IPv4-mapped IPv6 addresses
- ToIP4 does not correctly extract the IPv4 component from IPv4-mapped IPv6 addresses
- Bidirectional conversion (IPv4 → IPv6 → IPv4) does not preserve the original address
Expected Behavior
- ToIP6 should convert IPv4 addresses to the standard IPv4-mapped IPv6 format (::ffff:a.b.c.d)
- ToIP4 should extract and return the IPv4 component from IPv4-mapped IPv6 addresses
- Conversion should be bidirectionally consistent (IPv4 → IPv6 → IPv4 should return the original IPv4 address)
ip := "192.168.1.1"
ipv6, err := ToIP6(ip)
// Expected: ipv6 = "::ffff:192.168.1.1"
// Actual: Different format not conforming to standards
ipv6 := "::ffff:192.168.1.1"
ipv4, err := ToIP4(ipv6)
// Expected: ipv4 = "192.168.1.1"
// Actual: Error or incorrect extractionProposed Solution
Update the functions to handle the conversion properly:
1.ToIP6 should:
- Check if the input is already an IPv6 address
- For IPv4 addresses, convert to the format ::ffff:a.b.c.d
2.ToIP4 should:
- Check if the input is a native IPv4 address
- For IPv6 addresses, verify if it's an IPv4-mapped address (starts with ::ffff:)
- Extract the IPv4 component from valid IPv4-mapped addresses
- Return an error for non-IPv4-mapped IPv6 addresses