NAT64/Teredo Embedding Strategies + Public/Private Blocks#105
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zanbaldwin wants to merge 6 commits into
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NAT64/Teredo Embedding Strategies + Public/Private Blocks#105zanbaldwin wants to merge 6 commits into
zanbaldwin wants to merge 6 commits into
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Add embedding strategy for NAT64 "Well-Known Prefix" `64:ff9b::/96` defined by RFC 6052 § 2.1 (with test coverage and data providers). Include docblocks for the other strategies that explain their defining RFC.
Add composite embedding that delegates checks/extraction to multiple underlying strategies (always uses first-defined strategy for packing). Named constructor `all()` covers all unambiguous, non-deprecated embedding, with Mapped as the canonical packer. Includes test coverage and data provider.
isUnicastGlobal() only inspected 16-byte IPv6 form, meaning a non-global IPv4-embedded address (loopback, private, etc) was reported as global. Error also cascaded down to isPublicUse(). Bug could potentially allow a non-global address to slip past an SSRF/ACL guard/deny-list. Embedded addresses are now canonicalised before classifying. Note: IPv6 now checks ALL valid IPv4-embeddings (previously only Multi checked, and only checked its singularly-assigned embedding).
Add extraction-only embedding strategy for the Teredo tunnelling prefix `2001::/32` defined by RFC 4380 § 4 (with test coverage and data providers).
The IANA special-purpose registry lists the NAT64 local-use block `64:ff9b:1::/48` (defined by RFC 8215; different to the NAT64 well-known prefix) as not globally reachable, but `isUnicastGlobal()` and `isPublicUse()` report addresses within it as global. Fix: explicitly exlcude them. Operator-defined, cannot be decoded by an embedding strategy, must be excluded as a whole instead of being canonicalised.
Roman3349
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Jun 4, 2026
| * Globally reachable, but not reserved by protocol. RFC 6052 § 3.1 states that | ||
| * non-global IPv4 addresses must NOT be embedded as NAT64. | ||
| */ | ||
| class Nat64 implements EmbeddingStrategyInterface |
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Since NAT64 supports prefixes other than 64:ff9b::/96, would it be possible to add the option to specify a different checksum-neutral prefix for NAT64?
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I have been reading RFC specifications for nearly 2 days, so my brain needs a rest right now, but I have seen this and I will reply some time in the next couple of days 👍
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Thinking about adding named constructors to NAT64:
Nat64::wellKnown()(default, part ofComposite::all()), andNat64::networkSpecific(IPv6 $prefix, int $cidr)where$cidrmust be one of 32, 40, 48, 56, 64, or 96.- Also something about NAT64 local-use, because that entire block is defined as not globally reachable, but not sure where that logic is going to go (just made a private helper method in the other pull requests).
Will probably cancel this pull request, and do just the NAT64 stuff on its own in a new pull request on Monday. Will tag you in it for review (unless you leave any comments here before then).
Thanks for the suggestion!
zanbaldwin
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