(9) feat: fixed-size + lookup foundation trait crates#1573
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daniel-noland wants to merge 2 commits into
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(9) feat: fixed-size + lookup foundation trait crates#1573daniel-noland wants to merge 2 commits into
daniel-noland wants to merge 2 commits into
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Introduces a no_std FixedSize trait carrying a known byte width plus a big-endian write. Lives in its own crate so value-providing crates (`net`) and downstream key-packing frameworks (a future `match-action` PR) can both depend on it without depending on each other -- `net` implements FixedSize on its own newtypes without an orphan-rule violation, and the framework doesn't need to know about any particular value supplier. fixed-size/src/lib.rs: - pub trait FixedSize: Copy, with const SIZE: usize and fn write_be(&self, out: &mut [u8]). - Blanket impls for the network-order primitives the framework cares about: u8 / u16 / u32 / u64 / u128 / Ipv4Addr / Ipv6Addr. net/src/fixed_size.rs is the consumer bridge: FixedSize impls for TcpPort, UdpPort, UnicastIpv4Addr, and Vni. Each delegates write_be to the underlying primitive's impl, so wire bytes match what writing the raw integer would produce. Vni is a 24-bit value written into a 4-byte field (high byte zero) because backends model fields in 1/2/4 widths, not 3. net/Cargo.toml grows the fixed-size workspace dep; net/src/lib.rs adds the module behind no cfg gates (it has no further dependencies of its own). just fmt; cargo check --workspace --all-targets passes.
Adds the read-only key/action lookup vocabulary downstream match-action backends will implement. Tiny crate by design (one trait pair, two collection impls, inline tests) so consumer crates depend on this without depending on each other. lookup/src/lib.rs: - pub trait Projection<T>: extracts a key of type T from self. Implemented on `&'a Source` so the lifetime threads into T when T borrows; for owned T the lifetime is unused. The same source can implement Projection<T> for many T -- the call site picks one by inference from a Lookup backend's key type. - impl<K> Projection<Option<K>> for Option<K>: identity, so classify_opt accepts a pre-computed Option<K> directly. Scoped to Option<K> (not a general impl<T> Projection<T> for T) so a backend that implements Lookup<K, A> for every K can't make classify ambiguous. - pub trait Lookup<K, A>: lookup(&K) -> Option<&A>, plus default methods classify (S: Projection<K>) and classify_opt (S: Projection<Option<K>>) that project and look up in one call. Two trait type parameters, so one backend can serve many (K, A) pairs. - Blanket Lookup impls for BTreeMap<K, V> and HashMap<K, V, S> so tests / simple consumers get a working backend out of the box. Inline tests exercise: projection-by-table-type inference at v4 2-tuple and 4-tuple widths, lifetime threading through borrowed projections, miss returning None, classify_opt short-circuit on None projection, the identity Projection<Option<K>> for Option<K>, and HashMap parity with BTreeMap. just fmt; cargo check --workspace --all-targets passes.
This was referenced May 31, 2026
daniel-noland
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Pull request overview
Introduces two new foundational trait crates (fixed-size and lookup) intended to underpin upcoming match-action / ACL layers, and wires FixedSize implementations for selected net wire newtypes.
Changes:
- Added
dataplane-fixed-size(no_std) defining aFixedSizetrait plus base impls for integer and IP address types. - Added
dataplane-lookupdefiningLookup<K, A>andProjection<T>traits withBTreeMap/HashMapbackends and unit tests. - Integrated
fixed-sizeintonetand providedFixedSizeimpls forTcpPort,UdpPort,UnicastIpv4Addr, andVni.
Reviewed changes
Copilot reviewed 8 out of 9 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| net/src/lib.rs | Registers a private fixed_size module to host FixedSize impls for net types. |
| net/src/fixed_size.rs | Implements FixedSize for key net newtypes and adds unit tests for byte encoding. |
| net/Cargo.toml | Adds dependency on the new fixed-size crate. |
| fixed-size/src/lib.rs | Adds the new FixedSize trait crate and core impls for primitives/IP types. |
| fixed-size/Cargo.toml | Declares the new dataplane-fixed-size crate. |
| lookup/src/lib.rs | Adds the new Lookup/Projection trait crate plus unit tests and map backends. |
| lookup/Cargo.toml | Declares the new dataplane-lookup crate. |
| Cargo.toml | Adds both crates to the workspace, workspace dependencies, and wasm/miri metadata. |
| Cargo.lock | Records the two new workspace packages and updates dataplane-net deps. |
Comment on lines
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| pub trait FixedSize: Copy { | ||
| const SIZE: usize; | ||
| fn write_be(&self, out: &mut [u8]); | ||
| } |
mvachhar
approved these changes
Jun 1, 2026
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Stack (9). Base:
pr/daniel-noland/dpdk-test-eal.The two foundational leaf trait crates the match-action / ACL layers build on.
No DPDK, no
unsafe:feat(fixed-size):FixedSizetrait crate +impls fornetwire newtypes.feat(lookup):Lookup<K, A>+Projection<T>trait crate.Review stack (merge bottom -> top):