code.octet-stream.net Git - m17rt/blob - m17core/src/protocol.rs

   1 use crate::address::Address;
   2
   3 pub(crate) const LSF_SYNC: [i8; 8] = [1, 1, 1, 1, -1, -1, 1, -1];
   4 pub(crate) const BERT_SYNC: [i8; 8] = [-1, 1, -1, -1, 1, 1, 1, 1];
   5 pub(crate) const STREAM_SYNC: [i8; 8] = [-1, -1, -1, -1, 1, 1, -1, 1];
   6 pub(crate) const PACKET_SYNC: [i8; 8] = [1, -1, 1, 1, -1, -1, -1, -1];
   7
   8 #[derive(Debug, Clone, PartialEq, Eq)]
   9 pub enum Mode {
  10     Packet,
  11     Stream,
  12 }
  13 #[derive(Debug, Clone, PartialEq, Eq)]
  14 pub enum DataType {
  15     Reserved,
  16     Data,
  17     Voice,
  18     VoiceAndData,
  19 }
  20 #[derive(Debug, Clone, PartialEq, Eq)]
  21 pub enum EncryptionType {
  22     None,
  23     Scrambler,
  24     Aes,
  25     Other,
  26 }
  27
  28 #[derive(Debug, Clone, PartialEq, Eq)]
  29 pub enum Frame {
  30     Lsf(LsfFrame),
  31     Stream(StreamFrame),
  32     Packet(PacketFrame),
  33     // BERT
  34 }
  35
  36 #[derive(Debug, Clone, PartialEq, Eq)]
  37 pub enum PacketType {
  38     /// RAW
  39     Raw,
  40     /// AX.25
  41     Ax25,
  42     /// APRS
  43     Aprs,
  44     /// 6LoWPAN
  45     SixLowPan,
  46     /// IPv4
  47     Ipv4,
  48     /// SMS
  49     Sms,
  50     /// Winlink
  51     Winlink,
  52     /// Custom identifier
  53     Other(char),
  54 }
  55
  56 impl PacketType {
  57     pub fn from_proto(buf: &[u8]) -> Option<(Self, usize)> {
  58         buf.utf8_chunks()
  59             .next()
  60             .and_then(|chunk| chunk.valid().chars().next())
  61             .map(|c| match c as u32 {
  62                 0x00 => (PacketType::Raw, 1),
  63                 0x01 => (PacketType::Ax25, 1),
  64                 0x02 => (PacketType::Aprs, 1),
  65                 0x03 => (PacketType::SixLowPan, 1),
  66                 0x04 => (PacketType::Ipv4, 1),
  67                 0x05 => (PacketType::Sms, 1),
  68                 0x06 => (PacketType::Winlink, 1),
  69                 _ => (PacketType::Other(c), c.len_utf8()),
  70             })
  71     }
  72
  73     pub fn as_proto(&self) -> ([u8; 4], usize) {
  74         match self {
  75             PacketType::Raw => ([0, 0, 0, 0], 1),
  76             PacketType::Ax25 => ([1, 0, 0, 0], 1),
  77             PacketType::Aprs => ([2, 0, 0, 0], 1),
  78             PacketType::SixLowPan => ([3, 0, 0, 0], 1),
  79             PacketType::Ipv4 => ([4, 0, 0, 0], 1),
  80             PacketType::Sms => ([5, 0, 0, 0], 1),
  81             PacketType::Winlink => ([6, 0, 0, 0], 1),
  82             PacketType::Other(c) => {
  83                 let mut buf = [0u8; 4];
  84                 let s = c.encode_utf8(&mut buf);
  85                 let len = s.len();
  86                 (buf, len)
  87             }
  88         }
  89     }
  90 }
  91
  92 #[derive(Debug, Clone, PartialEq, Eq)]
  93 pub struct LsfFrame(pub [u8; 30]);
  94
  95 impl LsfFrame {
  96     pub fn crc(&self) -> u16 {
  97         crate::crc::m17_crc(&self.0)
  98     }
  99
 100     pub fn destination(&self) -> Address {
 101         crate::address::decode_address((&self.0[0..6]).try_into().unwrap())
 102     }
 103
 104     pub fn source(&self) -> Address {
 105         crate::address::decode_address((&self.0[6..12]).try_into().unwrap())
 106     }
 107
 108     pub fn mode(&self) -> Mode {
 109         if self.0[12] & 0x01 > 0 {
 110             Mode::Stream
 111         } else {
 112             Mode::Packet
 113         }
 114     }
 115
 116     pub fn data_type(&self) -> DataType {
 117         match (self.0[12] >> 1) & 0x03 {
 118             0b00 => DataType::Reserved,
 119             0b01 => DataType::Data,
 120             0b10 => DataType::Voice,
 121             0b11 => DataType::VoiceAndData,
 122             _ => unreachable!(),
 123         }
 124     }
 125
 126     pub fn encryption_type(&self) -> EncryptionType {
 127         match (self.0[12] >> 3) & 0x03 {
 128             0b00 => EncryptionType::None,
 129             0b01 => EncryptionType::Scrambler,
 130             0b10 => EncryptionType::Aes,
 131             0b11 => EncryptionType::Other,
 132             _ => unreachable!(),
 133         }
 134     }
 135
 136     // TODO: encryption sub-type
 137
 138     pub fn channel_access_number(&self) -> u8 {
 139         (self.0[12] >> 7) & 0x0f
 140     }
 141
 142     pub fn meta(&self) -> [u8; 14] {
 143         self.0[14..28].try_into().unwrap()
 144     }
 145 }
 146
 147 #[derive(Debug, Clone, PartialEq, Eq)]
 148 pub struct StreamFrame {
 149     /// Which LICH segment is given in this frame, from 0 to 5 inclusive
 150     pub lich_idx: u8,
 151     /// Decoded LICH segment
 152     pub lich_part: [u8; 5],
 153     /// Which frame in the transmission this is, starting from 0
 154     pub frame_number: u16,
 155     /// Is this the last frame in the transmission?
 156     pub end_of_stream: bool,
 157     /// Raw application data in this frame
 158     pub stream_data: [u8; 16],
 159 }
 160
 161 #[derive(Debug, Clone, PartialEq, Eq)]
 162 pub struct PacketFrame {
 163     /// Application packet payload (chunk)
 164     pub payload: [u8; 25],
 165
 166     /// Frame counter, which provides different information depending on whether this is the last frame or not.
 167     pub counter: PacketFrameCounter,
 168 }
 169
 170 #[derive(Debug, Clone, PartialEq, Eq)]
 171 pub enum PacketFrameCounter {
 172     /// Any packet frame that comes after the LSF and is not the final frame.
 173     Frame {
 174         /// Which frame this is in the superframe, from 0 to 31 inclusive.
 175         ///
 176         /// If a 33rd frame exists (index 32), it will be a `FinalFrame` instead.
 177         ///
 178         /// All 25 bytes of of `payload` are filled and valid.
 179         index: usize,
 180     },
 181     /// The final frame in the packet superframe.
 182     FinalFrame {
 183         /// The number of bytes in `payload` that are filled.
 184         payload_len: usize,
 185     },
 186 }
 187
 188 pub struct LichCollection([Option<[u8; 5]>; 6]);
 189
 190 impl LichCollection {
 191     pub fn new() -> Self {
 192         Self([None; 6])
 193     }
 194
 195     pub fn valid_segments(&self) -> usize {
 196         self.0.iter().filter(|s| s.is_some()).count()
 197     }
 198
 199     pub fn set_segment(&mut self, counter: u8, part: [u8; 5]) {
 200         self.0[counter as usize] = Some(part);
 201     }
 202
 203     pub fn try_assemble(&self) -> Option<[u8; 30]> {
 204         let mut out = [0u8; 30];
 205         for (i, segment) in self.0.iter().enumerate() {
 206             let Some(segment) = segment else {
 207                 return None;
 208             };
 209             for (j, seg_val) in segment.iter().enumerate() {
 210                 out[i * 5 + j] = *seg_val;
 211             }
 212         }
 213         Some(out)
 214     }
 215 }
 216
 217 impl Default for LichCollection {
 218     fn default() -> Self {
 219         Self::new()
 220     }
 221 }