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use crate::constants::ATCA_CMD_SIZE_MAX;
use crate::transport::TransportProtocol;
use crate::{
command::{EccCommand, EccResponse},
Address, DataBuffer, Error, KeyConfig, Result, SlotConfig, Zone,
};
use bytes::{BufMut, Bytes, BytesMut};
use sha2::{Digest, Sha256};
pub use crate::command::KeyType;
pub struct Ecc {
transport: TransportProtocol,
}
pub const MAX_SLOT: u8 = 15;
pub(crate) const CMD_RETRIES: u8 = 10;
impl Ecc {
pub fn from_path(path: &str, address: u16) -> Result<Self> {
let transport = TransportProtocol::from_path(path, address)?;
Ok(Self { transport })
}
pub fn get_info(&mut self) -> Result<Bytes> {
self.send_command(&EccCommand::info())
}
pub fn get_serial(&mut self) -> Result<Bytes> {
let bytes = self.read(true, &Address::config(0, 0)?)?;
let mut result = BytesMut::with_capacity(9);
result.extend_from_slice(&bytes.slice(0..=3));
result.extend_from_slice(&bytes.slice(8..=12));
Ok(result.freeze())
}
pub fn genkey(&mut self, key_type: KeyType, slot: u8) -> Result<Bytes> {
self.send_command(&EccCommand::genkey(key_type, slot))
}
pub fn get_slot_config(&mut self, slot: u8) -> Result<SlotConfig> {
let bytes = self.read(false, &Address::slot_config(slot)?)?;
let (s0, s1) = bytes.split_at(2);
match slot & 1 == 0 {
true => Ok(SlotConfig::from(s0)),
false => Ok(SlotConfig::from(s1)),
}
}
pub fn set_slot_config(&mut self, slot: u8, config: &SlotConfig) -> Result {
let slot_address = Address::slot_config(slot)?;
let bytes = self.read(false, &slot_address)?;
let (s0, s1) = bytes.split_at(2);
let mut new_bytes = BytesMut::with_capacity(4);
match slot & 1 == 0 {
true => {
new_bytes.put_u16(config.into());
new_bytes.extend_from_slice(s1);
}
false => {
new_bytes.extend_from_slice(s0);
new_bytes.put_u16(config.into());
}
}
self.write(&slot_address, &new_bytes.freeze())
}
pub fn get_key_config(&mut self, slot: u8) -> Result<KeyConfig> {
let bytes = self.read(false, &Address::key_config(slot)?)?;
let (s0, s1) = bytes.split_at(2);
match slot & 1 == 0 {
true => Ok(KeyConfig::from(s0)),
false => Ok(KeyConfig::from(s1)),
}
}
pub fn set_key_config(&mut self, slot: u8, config: &KeyConfig) -> Result {
let slot_address = Address::key_config(slot)?;
let bytes = self.read(false, &slot_address)?;
let (s0, s1) = bytes.split_at(2);
let mut new_bytes = BytesMut::with_capacity(4);
match slot & 1 == 0 {
true => {
new_bytes.put_u16(config.into());
new_bytes.extend_from_slice(s1);
}
false => {
new_bytes.extend_from_slice(s0);
new_bytes.put_u16(config.into());
}
}
self.write(&slot_address, &new_bytes.freeze())
}
pub fn get_locked(&mut self, zone: &Zone) -> Result<bool> {
let bytes = self.read(false, &Address::config(2, 5)?)?;
let (_, s1) = bytes.split_at(2);
match zone {
Zone::Config => Ok(s1[1] == 0),
Zone::Data => Ok(s1[0] == 0),
}
}
pub fn set_locked(&mut self, zone: Zone) -> Result {
self.send_command(&EccCommand::lock(zone)).map(|_| ())
}
pub fn sign(&mut self, key_slot: u8, data: &[u8]) -> Result<Bytes> {
let digest = Sha256::digest(data);
let _ = self.send_command_retries(
&EccCommand::nonce(DataBuffer::MessageDigest, Bytes::copy_from_slice(&digest)),
false,
1,
)?;
self.send_command_retries(
&EccCommand::sign(DataBuffer::MessageDigest, key_slot),
true,
1,
)
}
pub fn ecdh(&mut self, key_slot: u8, x: &[u8], y: &[u8]) -> Result<Bytes> {
self.send_command(&EccCommand::ecdh(
Bytes::copy_from_slice(x),
Bytes::copy_from_slice(y),
key_slot,
))
}
pub fn random(&mut self) -> Result<Bytes> {
self.send_command(&EccCommand::random())
}
pub fn nonce(&mut self, target: DataBuffer, data: &[u8]) -> Result {
self.send_command(&EccCommand::nonce(target, Bytes::copy_from_slice(data)))
.map(|_| ())
}
pub fn read(&mut self, read_32: bool, address: &Address) -> Result<Bytes> {
self.send_command(&EccCommand::read(read_32, address.clone()))
}
pub fn write(&mut self, address: &Address, bytes: &[u8]) -> Result {
self.send_command(&EccCommand::write(address.clone(), bytes))
.map(|_| ())
}
pub(crate) fn send_command(&mut self, command: &EccCommand) -> Result<Bytes> {
self.send_command_retries(command, true, CMD_RETRIES)
}
pub(crate) fn send_command_retries(
&mut self,
command: &EccCommand,
sleep: bool,
retries: u8,
) -> Result<Bytes> {
let mut buf = BytesMut::with_capacity(ATCA_CMD_SIZE_MAX as usize);
for retry in 0..retries {
buf.clear();
buf.put_u8(self.transport.put_command_flag());
command.bytes_into(&mut buf);
self.transport.send_wake()?;
let delay = self.transport.command_duration(command);
if let Err(_err) = self.transport.send_recv_buf(delay, &mut buf) {
if retry == retries {
break;
} else {
continue;
}
}
let response = EccResponse::from_bytes(&buf[..])?;
if sleep {
self.transport.send_sleep();
}
match response {
EccResponse::Data(bytes) => return Ok(bytes),
EccResponse::Error(err) if err.is_recoverable() && retry < retries => {
continue;
}
EccResponse::Error(err) => return Err(Error::ecc(err)),
}
}
Err(Error::timeout())
}
}
