kipuka_coap/
lib.rs

1//! EST over CoAP (RFC 9483) transport for constrained devices.
2//!
3//! This crate implements the CoAP transport binding for Enrollment over Secure
4//! Transport, enabling EST operations on constrained IoT devices that cannot
5//! use HTTP/TLS.
6//!
7//! # Protocol Mapping
8//!
9//! RFC 9483 maps EST operations to CoAP as follows:
10//! - HTTPS transport is replaced by CoAP over DTLS ("coaps")
11//! - EST URI paths use abbreviated names (e.g., `/sen` for `/simpleenroll`)
12//! - HTTP Content-Type headers map to CoAP Content-Format option IDs
13//! - Large payloads (PQC certificates can exceed 7KB) use RFC 7959 block-wise transfer
14//!
15//! # Modules
16//!
17//! - [`server`]: CoAP message parsing, encoding, and EST-coaps URI routing
18//! - [`dtls`]: DTLS session management abstraction for CoAP security
19//! - [`block`]: RFC 7959 block-wise transfer for large EST payloads
20//! - [`content_format`]: CoAP content-format IDs for EST media types (RFC 9483 §5.4)
21
22pub mod block;
23pub mod content_format;
24pub mod dtls;
25pub mod server;
26
27use thiserror::Error;
28
29/// Errors arising from CoAP/EST-coaps protocol handling.
30#[derive(Debug, Error, Clone)]
31pub enum CoapError {
32    /// Malformed CoAP message (header, token, or option encoding).
33    #[error("Invalid CoAP message: {0}")]
34    InvalidMessage(String),
35
36    /// Unrecognized or unsupported CoAP method code.
37    #[error("Unsupported CoAP method: {0}")]
38    UnsupportedMethod(String),
39
40    /// Unrecognized CoAP Content-Format option value.
41    ///
42    /// RFC 9483 §5.4 defines the content-format IDs that EST-coaps supports.
43    #[error("Unsupported Content-Format: {0}")]
44    UnsupportedContentFormat(u16),
45
46    /// Block-wise transfer failure per RFC 7959.
47    #[error("Block transfer error: {0}")]
48    BlockTransferError(String),
49
50    /// DTLS session establishment or resumption failure.
51    ///
52    /// RFC 9483 §5 requires DTLS to secure all EST-coaps exchanges.
53    #[error("DTLS error: {0}")]
54    DtlsError(String),
55
56    /// Payload exceeds the configured maximum size.
57    ///
58    /// Even with block-wise transfer, reassembled payloads are bounded to
59    /// prevent resource exhaustion on constrained devices.
60    #[error("Payload too large: {size} bytes exceeds maximum {max} bytes")]
61    PayloadTooLarge {
62        /// Actual payload size in bytes.
63        size: usize,
64        /// Configured maximum payload size in bytes.
65        max: usize,
66    },
67
68    /// No CoAP resource matches the requested URI path.
69    #[error("Resource not found: {0}")]
70    ResourceNotFound(String),
71
72    /// Internal server error (catch-all).
73    #[error("Internal error: {0}")]
74    Internal(String),
75}
76
77/// Result type for CoAP operations.
78pub type CoapResult<T> = Result<T, CoapError>;
kipuka_coap/lib.rs

kipuka_coap/
lib.rs
