# Dependencies

Every external crate has a row here. `scripts/check-dep-docs.sh` enforces it.

| Crate | Version | Used by | Why |
|---|---|---|---|
| `serde` | 1.0.229 | `proto`, `brokerd`, `toolkit`, `gatewayd` | Derives serialization for every shared type. MIT OR Apache-2.0. |
| `serde_json` | 1.0.151 | `proto`, `brokerd`, `toolkit`, `gatewayd` | JSON for frames and log files. MIT OR Apache-2.0. |
| `humantime` | 2.4.0 | `proto` | RFC 3339 timestamps. No dependencies of its own. MIT OR Apache-2.0. |
| `toml` | 1.1.6 | `proto` tests; `brokerd` and `bxctl` from M3, `gatewayd` from M4a | Parses grant files. MIT OR Apache-2.0. |
| `emsha` | 1.0.4 | `proto` | SHA-256. Written by the owner; no dependencies, no `unsafe`. Checked against `sha256sum` on 3,204 inputs. |
| `rustls` | 0.23.45 | `gatewayd` | TLS to Mattermost over the tailnet (M4a, owner's decision). `default-features = false` with `ring`, `std`, `tls12`. With its dependencies on Linux: `ring` (Apache-2.0 AND ISC; builds C and assembly), `rustls-webpki` and `untrusted` (ISC), `rustls-pki-types`, `subtle` (BSD-3-Clause), `zeroize`, `once_cell`, `getrandom`, `libc`, `cfg-if`. Apache-2.0 OR ISC OR MIT. |
| `rustls-native-certs` | 0.8.4 | `gatewayd` | The host's trusted certificates, so a CA installed on the host is trusted too; adds `openssl-probe`. Apache-2.0 OR ISC OR MIT. |
| `zeroize` | 1.9.0 | `gatewayd` | Wipes a secret's memory when it is dropped (`Secret`). Already a dependency of `rustls`. Apache-2.0 OR MIT. |

## Build inputs

`flake.nix` has one input, `nixpkgs`, pinned to `nixos-26.05` in `flake.lock`: the release the
owner's NixOS hosts run, so a host's config can use the flake with
`inputs.boxmaker.inputs.nixpkgs.follows = "nixpkgs"`. It has Rust 1.95.0, the workspace's
`rust-version`. Nix fetches it when building, never the harness when running, so it is not in
`docs/egress.md`.

- `nix build` builds every binary (`result/bin/`); the tests are not run there, only in `make gate`.
- `nix build .#tools-image` builds the tool containers' image (`deploy/tools-image.nix`).
- `nix develop` gives a shell with `cargo`, `rustc`, `clippy`, `rustfmt`, `cargo-deny` and `make`.