docs(examples/coap): Split out minimal server example

examples/coap-server/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "coap-server"
+version = "0.1.0"
+authors = ["Christian Amsüss <[email protected]>"]
+license.workspace = true
+edition.workspace = true
+publish = false
+
+[lints]
+workspace = true
+
+[dependencies]
+embassy-net = { workspace = true, features = ["udp"] }
+embassy-sync = { workspace = true }
+heapless = { workspace = true }
+ariel-os = { path = "../../src/ariel-os", features = [
+  "override-network-config",
+  "coap",
+] }
+ariel-os-boards = { path = "../../src/ariel-os-boards" }
+coap-message = "0.3.2"
+coap-message-demos = { version = "0.4.0", default-features = false }
+coap-handler = "0.2.0"
+coap-handler-implementations = "0.5.0"
+
+static-alloc = { version = "0.2.5", features = ["polyfill"] }
+
+ariel-os-coap = { workspace = true }

examples/coap-server/README.md

@@ -0,0 +1,45 @@
+# coap server demo
+
+## About
+
+This application starts a minimal CoAP server.
+
+The server offers a single resource, `/hello`, which returns a friendly message.
+
+The default policy allows access to the resource,
+but clients can cryptographically verify that they are talking to the right server using its public key.
+Both the policy and the key are currently hard-coded;
+making the former configurable and the latter dynamic is work in progress.
+
+## Running
+
+* Run on any board with networking, eg. `laze build -b particle-xenon run`.
+* [Set up networking](../README.md).
+* Run `aiocoap-client`
+  to list the resources of the device:
+
+  ```sh
+  $ pipx install 'aiocoap[all]'
+  $ aiocoap-client coap://10.42.0.61/.well-known/core --credentials client.diag
+  # application/link-format content was re-formatted
+  </hello>
+  ```
+
+  If you prefer not to install the CoAP client, you can
+  replace any call to `aiocoap-client` with `pipx run --spec 'aiocoap[all]' aiocoap-client` instead.
+
+  The output tells you there is a `/hello` resource, so read that next:
+
+  ```sh
+  $ aiocoap-client coap://10.42.0.61/hello --credentials client.diag
+  Hello from Ariel OS
+  ```
+
+  The argument `--credentials client.diag` tells the client to establish a secure connection.
+  Without the argument, the requests come through just as well,
+  but the client has no assurance on the server's identity.
+
+## Further references
+
+There is a [chapter in the book](https://ariel-os.github.io/ariel-os/dev/docs/book/tooling/coap.html)
+that describes more concepts and background.

examples/coap-server/client.cosekey

@@ -0,0 +1 @@
+{1: 2, -1: 1, -4: h'fb13adeb6518cee5f88417660841142e830a81fe334380a953406a1305e8706b'}

examples/coap-server/client.diag

@@ -0,0 +1,13 @@
+{
+  "coap://10.42.0.61/*": {
+    "edhoc-oscore": {
+      "suite": 2,
+      "method": 3,
+      "own_cred_style": "by-value",
+      / From the server's point of view, this is unauthenticated; we could use any key pair, as long as we send it by value. /
+      "own_cred": {14: {2: "", 8: {1: {1: 2, 2: h'2b', -1: 1, -2: h'ac75e9ece3e50bfc8ed60399889522405c47bf16df96660a41298cb4307f7eb6', -3: h'6e5de611388a4b8a8211334ac7d37ecb52a387d257e6db3c2a93df21ff3affc8'}}}},
+      "private_key_file": "client.cosekey",
+      "peer_cred": {14: {2: "", 8: {1: {1: 2, 2: h'0a', -1: 1, -2: h'bbc34960526ea4d32e940cad2a234148ddc21791a12afbcbac93622046dd44f0', -3: h'4519e257236b2a0ce2023f0931f1f386ca7afda64fcde0108c224c51eabf6072'}}}},
+    }
+  },
+}

examples/coap-server/laze.yml

@@ -0,0 +1,16 @@
+apps:
+  - name: coap-server
+    env:
+      global:
+        CARGO_ENV:
+          - CONFIG_ISR_STACKSIZE=16384
+    selects:
+      - ?release
+      - network
+      - random
+    conflicts:
+      # see https://github.com/ariel-os/ariel-os/issues/418
+      - thumbv6m-none-eabi
+      # no xtensa / riscv gcc on CI
+      - xtensa
+      - riscv

examples/coap-server/src/main.rs

@@ -0,0 +1,37 @@
+#![no_main]
+#![no_std]
+#![feature(impl_trait_in_assoc_type)]
+#![feature(used_with_arg)]
+
+// Due to mismatches between CoAP components, coapcore currently needs an allocator. This example
+// provides the one that can be made most easily.
+extern crate alloc;
+use static_alloc::Bump;
+#[global_allocator]
+static A: Bump<[u8; 1 << 16]> = Bump::uninit();
+
+#[ariel_os::task(autostart)]
+async fn coap_run() {
+    use coap_handler_implementations::{
+        new_dispatcher, HandlerBuilder, ReportingHandlerBuilder, SimpleRendered,
+    };
+
+    let handler = new_dispatcher()
+        // We offer a single resource: /hello, which response just with a text string.
+        .at(&["hello"], SimpleRendered("Hello from Ariel OS"))
+        .with_wkc();
+
+    ariel_os::coap::coap_run(handler).await;
+}
+
+// So far, this is necessary boiler plate; see ../../README.md#networking for details
+#[ariel_os::config(network)]
+fn network_config() -> embassy_net::Config {
+    use embassy_net::Ipv4Address;
+
+    embassy_net::Config::ipv4_static(embassy_net::StaticConfigV4 {
+        address: embassy_net::Ipv4Cidr::new(Ipv4Address::new(10, 42, 0, 61), 24),
+        dns_servers: heapless::Vec::new(),
+        gateway: Some(Ipv4Address::new(10, 42, 0, 1)),
+    })
+}

examples/laze.yml

@@ -8,6 +8,7 @@ subdirs:
   - blinky
   - core-sizes
   - coap
+  - coap-server
   - device-metadata
   - embassy-http-server
   - embassy-usb-keyboard