doca-sha

# DOCA SHA ## Examples - **"Offload SHA-256 to the BlueField."** — this is in scope. Use the shipped SHA sample and `doca_sha_cap_*` before picking SHA-1 / SHA-256 / SHA-512. - **"Partial hash returns BAD_STATE."** — stay on the incremental `doca_sha_task_partial_hash` lifecycle; do not switch to a CPU hash library mid-stream. ## Instructions Follow Loading order below. Open the tasks companion for configure / build / run. Open the capabilities companion for one-shot vs partial hash and algorithm support. Do not open every companion file. **Where to start:** This skill assumes DOCA is already installed and the user is doing **hands-on SHA-acceleration work** on a BlueField-2 DPU (Arm side or its host) with DOCA. BlueField-3 has no SHA engine. Open the tasks companion if the user wants to *do* something (configure / build / modify / run / test / debug); open the capabilities companion when the question is *what can DOCA SHA express* on this version. If the user has not installed DOCA yet, route to `doca-setup/SKILL.md` first. If the user is asking *"should I even use the accelerator for this hash?"*, the path-selection rule in ## Capabilities and modes is the first stop. **How to use this skill.** Read this file, then search the companion file for the `## <name>` heading the question needs and read that whole section. Answer completely from it, quoting only its symbols and commands. Do not browse docs; use the entry points in `doca-public-knowledge-map`. Give environment checks as commands for the user's DOCA host. For out-of-scope requests, name the skill that owns them and stop. ## Example questions this skill answers well The CLASSES of DOCA SHA questions this skill is built to answer, each with one worked example. The agent should treat the *class* as the load-bearing piece — the worked example is a single instance. - **"Should I offload this hash to DOCA SHA, or just compute it on the CPU?"** — worked example: *"I am verifying file integrity on a 4 GiB image; is doca-sha worth the setup vs OpenSSL on the CPU?"*. Answered by the path-selection table in ## Capabilities and modes + the *"when NOT to use doca-sha"* bullets in ## Safety policy. - **"Does my device support the SHA algorithm I want?"** — worked example: *"is SHA-256 in the accelerator on this BlueField, and what is the minimum destination buffer size for it?"*. Answered by the algorithm + buffer-sizing capability-query rule (`doca_sha_cap_task_hash_get_supported(devinfo, algorithm)` for the one-shot path; `_task_partial_hash_get_supported(devinfo, algorithm)` for the partial-hash path; `doca_sha_cap_get_min_dst_buf_size`, `doca_sha_cap_get_max_src_buf_size`) in ## Capabilities and modes + the discovery step in ## configure. - **"How do I pick between the one-shot and the partial / incremental hash task?"** — worked example: *"my input is 1 GiB and the device cap says max source buffer is 64 MiB"*. Answered by the one-shot-vs-partial table in ## Capabilities and modes + the task-config workflow in ## modify. - **"What permissions does the source / destination mmap need?"** — worked example: *"my `doca_sha_task_hash` returns `DOCA_ERROR_NOT_PERMITTED`"*. Answered by the permission matrix in ## Safety policy + the mmap-set-permissions checklist in ## test. - **"Is this DOCA SHA API available on my installed DOCA version?"** — worked example: *"is `doca_sha_task_partial_hash` in the DOCA I have installed?"*. Answered by the version-compatibility overlay in ## Version compatibility, which cross-links the canonical detection chain in `doca-version/SKILL.md` and adds the SHA-specific *"discover, do not assume"* bullets. - **"What does this `DOCA_ERROR_*` from a SHA call mean and which layer caused it?"** — worked example: *"`DOCA_ERROR_INVALID_VALUE` on `doca_sha_task_hash_alloc_init`"*. Answered by the SHA overlay on the cross-library taxonomy in ## Error taxonomy + the layered ladder in ## debug that escalates to `doca-debug/SKILL.md`. ## Audience This skill serves **external developers building applications that consume the DOCA SHA library** — i.e., users whose code calls `doca_sha_*` (directly in C/C++, or through FFI/bindings from another language) to offload SHA hashing onto the BlueField-2 SHA engine (BlueField-3 has none). It is *not* for NVIDIA developers contributing to DOCA SHA itself. **Language scope.** DOCA SHA ships as a C library with `pkg-config` module name `doca-sha`. The shipped samples are written in C. C and C++ consumers are the canonical case and the worked examples in the tasks companion assume that path. Other-language consumers (Rust, Go, Python, …) consume the same `*.so` through FFI or language-specific bindings; the skill's contribution in that case is to keep the lifecycle, capability-discovery, permission, error-taxonomy, and one-shot-vs-partial guidance language-neutral, and to route the agent to the public C ABI as the authoritative surface that any wrapper will eventually call. ## When to load this skill Load this skill when the user is doing hands-on DOCA SHA work, in any language. Concretely: - Initializing a `doca_sha` context on a `doca_dev` and configuring at least one task type (`doca_sha_task_hash` and/or `doca_sha_task_partial_hash`) before `doca_ctx_start()`. - Choosing between the **one-shot** task (`doca_sha_task_hash` — input fits in a single source buffer, output digest lands in a single destination buffer) and the **partial / incremental** task (`doca_sha_task_partial_hash` — input streamed in chunks, finalized separately) for the user's data shape. - Setting permissions on `doca_mmap` correctly for the source buffer (`DOCA_ACCESS_FLAG_LOCAL_READ_ONLY` at minimum) and the destination buffer (`DOCA_ACCESS_FLAG_LOCAL_READ_WRITE`). - Sizing the destination buffer against `doca_sha_cap_get_min_dst_buf_size(devinfo, algorithm)` and the source buffer against `doca_sha_cap_get_max_src_buf_size(devinfo)`. - Checking which SHA algorithm enums (`DOCA_SHA_ALGORITHM_SHA1`, `DOCA_SHA_ALGORITHM_SHA256`, `DOCA_SHA_ALGORITHM_SHA512`) the active device's accelerator advertises, via `doca_sha_cap_task_hash_get_supported(devinfo, algorithm)` and `doca_sha_cap_task_partial_hash_get_supported(devinfo, algorithm)` — both fold task-support and algorithm-support into one call. - Validating a digest against a published test vector before pushing bulk input through the accelerator. - Debugging a `DOCA_ERROR_*` returned from a SHA call (lifecycle vs. buffer-sizing vs. permission vs. unsupported-algorithm) and the task-completion event on the progress engine. - Designing or extending non-C bindings (Rust, Go, Python, …) that wrap the SHA C ABI — for the lifecycle, permission, capability, and one-shot-vs-partial rules the wrapper must honor. Do **not** load this skill for general DOCA orientation, install of DOCA itself, non-SHA hashing libraries on CPU (use OpenSSL or similar), or other DOCA libraries. For those, use `doca-public-knowledge-map/SKILL.md`. ## What this skill provides This is a **thin loader**. The body keeps only the orientation needed to pick the right next file. The substantive SHA-specific material lives in two companion files: - the capabilities companion — what DOCA SHA can express on this version: the two task types (one-shot hash and partial / incremental hash), the three algorithm enums, the capability-query surface (`doca_sha_cap_*` for algorithm support and buffer sizing), the SHA error taxonomy (mapped onto the cross-library `DOCA_ERROR_*` set), the observability surface (per-task completion events on the progress engine), the safety policy that gates source / destination mmap permission decisions, and the path-selection rule (when to use doca-sha versus a CPU hash or a different DOCA crypto library). - the tasks companion — step-by-step workflows for the six in-scope SHA verbs: `configure`, `build`, `modify`, `run`, `test`, `debug`. Plus a `Deferred task verbs` block that points out-of-scope questions at the right next skill. The skill assumes a host or BlueField where DOCA is already installed at the standard location and the user has the privileges their public install profile expects. It does not cover installing DOCA — that path goes through `doca-setup/SKILL.md`. ## What this skill deliberately does not ship This skill is **agent guidance**, not a samples or templates bundle. To keep the boundary clean, it deliberately does not contain — and pull requests should not add: - **Pre-written DOCA SHA application source code, in any language.** The verified SHA source code is the shipped C samples at `/opt/mellanox/doca/samples/doca_sha/`, plus the File Integrity reference application linked from the public DOCA SHA guide. The agent's job is to route the user to those files and prescribe a minimum-diff modification on them via the universal modify-a-sample workflow in `doca-programming-guide/SKILL.md`, layered with the SHA-specific overrides in ## modify. - **Pre-computed digest tables for arbitrary inputs.** The skill tells the agent to use a *published* test vector (e.g. the NIST SHA test vectors for the empty string, "abc", and the million-`a` input) as the known-vector smoke; it does not ship a vector bank of its own. - **Standalone build manifests** (`meson.build`, `CMakeLists.txt`, `Cargo.toml`, …) parked inside the skill. The agent constructs the build manifest *in the user's project directory* against the user's installed DOCA, where `pkg-config --modversion doca-sha` is the source of truth. - **A `samples/`, `bindings/`, or `reference/` subtree** of any kind. A mock or incomplete artifact in this skill's tree, even one labeled "reference", is misleading: users will read it as buildable. ## Loading order 1. Read this skill first to confirm the user's question is in scope. 2. **For the SHA capability matrix, algorithm enums, one-shot vs partial task split, capability-query rules, permission matrix, error taxonomy, observability, and safety / path-selection policy, see the capabilities companion.** 3. **For step-by-step workflows — configure, build, modify, run, test, debug — see the tasks companion.** Both companion files cross-link to each other, `doca-version/SKILL.md` for the canonical version-handling rules, and `doca-public-knowledge-map/SKILL.md` whenever the right answer is "look it up in the public docs or the installed package layout" rather than "SHA-specific guidance". ## Related skills - `doca-public-knowledge-map/SKILL.md` — the routing table for every public DOCA documentation source and the on-disk layout of an installed DOCA package. The DOCA SHA page lives at `docs.nvidia.com/doca/sdk/DOCA-SHA/`; the File Integrity reference application is the canonical worked example. - `doca-setup/SKILL.md` — env preparation, install verification, and the *I have no install yet* path with the public NGC DOCA container. This skill assumes its preconditions are satisfied. - `doca-version/SKILL.md` — canonical DOCA version-handling rules. This skill's `## Version compatibility` cross-links the four-way match rule and adds only the SHA-specific *"discover algorithms + buffer sizes via cap query"* overlay. - `doca-structured-tools-contract/SKILL.md` — the bundle's structured-tools precedence rule (detect / prefer / fall back / report). The Command appendix in the tasks companion honors this contract. - `doca-programming-guide/SKILL.md` — general DOCA programming patterns shared by every library: the canonical `pkg-config` + meson build pattern, the universal modify-a-shipped-sample first-app workflow, the universal lifecycle, the cross-library `DOCA_ERROR_*` taxonomy, and the program-side debug order. This skill layers SHA specifics on top. - `doca-debug/SKILL.md` — the cross-cutting debug ladder (install / version / build / link / runtime / program / driver). SHA-specific debug (algorithm-not-supported, destination-buffer-too-small, partial-hash-out-of-order) overlays on top of that ladder.