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560: IEEE802154: getters for security fields r=Dirbaio a=thibautvdv

This adds getters for the security fields of the IEEE802154 frame. Also added a test for it.

`src/wire/ieee802154.rs` also contained a function for calculating the CRC. However, this is not needed and thus I also remove it in this PR.

Co-authored-by: Thibaut Vandervelden <[email protected]>
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@bors @thvdveld
bors[bot] and thvdveld authored Oct 26, 2021
2 parents c8141bb + 2a8ef37 commit 2dfc159
Showing 1 changed file with 159 additions and 66 deletions.
225 changes: 159 additions & 66 deletions src/wire/ieee802154.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,45 +6,6 @@ use crate::wire::ipv6::Address as Ipv6Address;
use crate::Error;
use crate::Result;

const CRC_TABLE: [u16; 256] = [
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, 0x9dc1, 0xaf5a, 0xbed3,
0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 0x2102, 0x308b, 0x0210, 0x1399,
0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb, 0xac42, 0x9ed9, 0x8f50,
0xfbef, 0xea66, 0xd8fd, 0xc974, 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285, 0x430c, 0x7197, 0x601e,
0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5,
0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 0x8408, 0x9581, 0xa71a, 0xb693,
0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, 0x0948, 0x3bd3, 0x2a5a,
0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 0xb58b, 0xa402, 0x9699, 0x8710,
0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44, 0x5bcd, 0x6956, 0x78df,
0x0c60, 0x1de9, 0x2f72, 0x3efb, 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e, 0xf687, 0xc41c, 0xd595,
0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c,
0x3de3, 0x2c6a, 0x1ef1, 0x0f78,
];

pub fn calculate_crc(buffer: &[u8]) -> u16 {
fn crc_byte(crc: u16, c: u8) -> u16 {
(crc >> 8) ^ CRC_TABLE[((crc ^ (c as u16)) & 0xff) as usize]
}

let mut crc = 0;

for b in buffer {
crc = crc_byte(crc, *b);
}

crc
}

enum_with_unknown! {
/// IEEE 802.15.4 frame type.
pub enum FrameType(u8) {
Expand Down Expand Up @@ -288,7 +249,8 @@ impl<T: AsRef<[u8]>> Frame<T> {
/// Ensure that no accessor method will panic if called.
/// Returns `Err(Error::Truncated)` if the buffer is too short.
pub fn check_len(&self) -> Result<()> {
if self.buffer.as_ref().is_empty() {
// We need at least 3 bytes
if self.buffer.as_ref().len() < 3 {
Err(Error::Truncated)
} else {
Ok(())
Expand Down Expand Up @@ -476,27 +438,118 @@ impl<T: AsRef<[u8]>> Frame<T> {
}
}

/// Return the Auxilliary Security Header Field
#[inline]
pub fn aux_security_header(&self) -> Option<&[u8]> {
match self.frame_type() {
FrameType::Beacon
| FrameType::Data
| FrameType::MacCommand
| FrameType::Multipurpose => (),
FrameType::Acknowledgement if self.frame_version() == FrameVersion::Ieee802154 => (),
FrameType::Acknowledgement
| FrameType::Extended
| FrameType::FragmentOrFrak
| FrameType::Unknown(_) => return None,
/// Return the index where the auxiliary security header starts.
fn aux_security_header_start(&self) -> usize {
// We start with 3, because 2 bytes for frame control and the sequence number.
let mut index = 3;
index += self.addressing_fields().unwrap().len();
index
}

/// Return the index where the payload starts.
fn payload_start(&self) -> usize {
let mut index = self.aux_security_header_start();

if self.security_enabled() {
// We add 5 because 1 byte for control bits and 4 bytes for frame counter.
index += 5;
index += if let Some(len) = self.key_identifier_length() {
len as usize
} else {
0
};
}

if !self.security_enabled() {
return None;
index
}

/// Return the lenght of the key identifier field.
fn key_identifier_length(&self) -> Option<u8> {
Some(match self.key_identifier_mode() {
0 => 0,
1 => 1,
2 => 5,
3 => 9,
_ => return None,
})
}

/// Return the security level of the auxiliary security header.
pub fn security_level(&self) -> u8 {
let index = self.aux_security_header_start();
let b = self.buffer.as_ref()[index..][0];
b & 0b111
}

/// Return the key identifier mode used by the auxiliary security header.
pub fn key_identifier_mode(&self) -> u8 {
let index = self.aux_security_header_start();
let b = self.buffer.as_ref()[index..][0];
(b >> 3) & 0b11
}

/// Return the frame counter field.
pub fn frame_counter(&self) -> u32 {
let index = self.aux_security_header_start();
let b = &self.buffer.as_ref()[index..];
LittleEndian::read_u32(&b[1..1 + 4])
}

/// Return the Key Identifier field.
fn key_identifier(&self) -> &[u8] {
let index = self.aux_security_header_start();
let b = &self.buffer.as_ref()[index..];
let length = if let Some(len) = self.key_identifier_length() {
len as usize
} else {
0
};
&b[5..][..length]
}

/// Return the Key Source field.
pub fn key_source(&self) -> Option<&[u8]> {
let ki = self.key_identifier();
let len = ki.len();
if len > 1 {
Some(&ki[..len - 1])
} else {
None
}
}

/// Return the Key Index field.
pub fn key_index(&self) -> Option<u8> {
let ki = self.key_identifier();
let len = ki.len();

if len > 0 {
Some(ki[len - 1])
} else {
None
}
}

/// Return the Message Integrity Code (MIC).
pub fn message_integrity_code(&self) -> Option<&[u8]> {
let mic_len = match self.security_level() {
0 | 4 => return None,
1 | 5 => 4,
2 | 6 => 8,
3 | 7 => 16,
_ => panic!(),
};

let data = &self.buffer.as_ref();
let len = data.len();

net_debug!("Auxilliary security header is currently not supported.");
None
Some(&data[len - mic_len..])
}

/// Return the MAC header.
pub fn mac_header(&self) -> &[u8] {
let data = &self.buffer.as_ref();
&data[..self.payload_start()]
}
}

Expand All @@ -506,10 +559,10 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Frame<&'a T> {
pub fn payload(&self) -> Option<&'a [u8]> {
match self.frame_type() {
FrameType::Data => {
let data = &self.buffer.as_ref()[field::ADDRESSING];
let offset = self.addressing_fields().unwrap().len();
let index = self.payload_start();
let data = &self.buffer.as_ref();

Some(&data[offset..])
Some(&data[index..])
}
_ => None,
}
Expand Down Expand Up @@ -652,12 +705,9 @@ impl<T: AsRef<[u8]> + AsMut<[u8]>> Frame<T> {
pub fn payload_mut(&mut self) -> Option<&mut [u8]> {
match self.frame_type() {
FrameType::Data => {
let mut start_offset = 3;
start_offset += self.addressing_fields().unwrap().len();

let index = self.payload_start();
let data = self.buffer.as_mut();
let end_offset = start_offset + data.len() - 2;
Some(&mut data[start_offset..end_offset])
Some(&mut data[index..])
}
_ => None,
}
Expand Down Expand Up @@ -892,6 +942,49 @@ mod test {
dst_addressing_mode -> AddressingMode::Short,
frame_version -> FrameVersion::Ieee802154_2006,
src_addressing_mode -> AddressingMode::Extended,
//payload -> Some(&[0x2b, 0x00, 0x00, 0x00]),
payload -> Some(&[0x2b, 0x00, 0x00, 0x00][..]),
}

vector_test! {
security
[
0x69,0xdc, // frame control
0x32, // sequence number
0xcd,0xab, // destination PAN id
0xbf,0x9b,0x15,0x06,0x00,0x4b,0x12,0x00, // extended destination address
0xc7,0xd9,0xb5,0x14,0x00,0x4b,0x12,0x00, // extended source address
0x05, // security control field
0x31,0x01,0x00,0x00, // frame counter
0x3e,0xe8,0xfb,0x85,0xe4,0xcc,0xf4,0x48,0x90,0xfe,0x56,0x66,0xf7,0x1c,0x65,0x9e,0xf9, // data
0x93,0xc8,0x34,0x2e,// MIC
];
frame_type -> FrameType::Data,
security_enabled -> true,
frame_pending -> false,
ack_request -> true,
pan_id_compression -> true,
dst_addressing_mode -> AddressingMode::Extended,
frame_version -> FrameVersion::Ieee802154_2006,
src_addressing_mode -> AddressingMode::Extended,
dst_pan_id -> Some(Pan(0xabcd)),
dst_addr -> Some(Address::Extended([0x00,0x12,0x4b,0x00,0x06,0x15,0x9b,0xbf])),
src_pan_id -> None,
src_addr -> Some(Address::Extended([0x00,0x12,0x4b,0x00,0x14,0xb5,0xd9,0xc7])),
security_level -> 5,
key_identifier_mode -> 0,
frame_counter -> 305,
key_source -> None,
key_index -> None,
payload -> Some(&[0x3e,0xe8,0xfb,0x85,0xe4,0xcc,0xf4,0x48,0x90,0xfe,0x56,0x66,0xf7,0x1c,0x65,0x9e,0xf9,0x93,0xc8,0x34,0x2e][..]),
message_integrity_code -> Some(&[0x93, 0xC8, 0x34, 0x2E][..]),
mac_header -> &[
0x69,0xdc, // frame control
0x32, // sequence number
0xcd,0xab, // destination PAN id
0xbf,0x9b,0x15,0x06,0x00,0x4b,0x12,0x00, // extended destination address
0xc7,0xd9,0xb5,0x14,0x00,0x4b,0x12,0x00, // extended source address
0x05, // security control field
0x31,0x01,0x00,0x00, // frame counter
][..],
}
}

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