git.scottworley.com Git - tattlekey/blob - server/src/main.rs

   1 // tattlekey: A one-key UDP keyboard
   2 // Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16
  17 use serde::Serialize;
  18 use std::collections::HashMap;
  19 use std::net::UdpSocket;
  20 use std::time::{Duration, SystemTime};
  21
  22 const MESSAGE_SIZE: usize = 12;
  23
  24 #[derive(Eq, Debug, Hash, PartialEq, Serialize)]
  25 struct MessageKey {
  26     epoch: u32,
  27     device: u16,
  28     seq: u16,
  29 }
  30
  31 #[derive(Debug)]
  32 struct Message {
  33     key: MessageKey,
  34     t: SystemTime,
  35 }
  36
  37 impl From<&[u8; MESSAGE_SIZE]> for Message {
  38     fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
  39         let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
  40         Self {
  41             key: MessageKey {
  42                 epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
  43                 device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
  44                 seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
  45             },
  46             t: SystemTime::now() - Duration::new(ago.into(), 0),
  47         }
  48     }
  49 }
  50 impl TryFrom<&[u8]> for Message {
  51     type Error = std::array::TryFromSliceError;
  52     fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
  53         match <[u8; MESSAGE_SIZE]>::try_from(value) {
  54             Ok(correct_size) => Ok(Message::from(&correct_size)),
  55             Err(e) => Err(e),
  56         }
  57     }
  58 }
  59
  60 #[derive(Debug)]
  61 struct Range {
  62     start: SystemTime,
  63     end: SystemTime,
  64 }
  65 impl Range {
  66     fn new(t: &SystemTime) -> Self {
  67         Self { start: *t, end: *t }
  68     }
  69     fn contains(&self, t: &SystemTime) -> bool {
  70         t > &self.start && t < &self.end
  71     }
  72     fn extend(&mut self, t: &SystemTime) {
  73         if t < &self.start {
  74             self.start = *t;
  75         }
  76         if t > &self.end {
  77             self.end = *t;
  78         }
  79     }
  80 }
  81
  82 fn main() {
  83     let mut log = csv::Writer::from_writer(std::io::stdout());
  84     let mut presses = HashMap::<MessageKey, Range>::new();
  85     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
  86     loop {
  87         let mut buf = [0; MESSAGE_SIZE];
  88         match socket.recv_from(&mut buf) {
  89             Err(e) => eprintln!("Didn't receive data: {e}"),
  90             Ok((number_of_bytes, src_addr)) => {
  91                 let filled_buf = &buf[..number_of_bytes];
  92                 if number_of_bytes != MESSAGE_SIZE {
  93                     eprintln!("Ignoring short message ({number_of_bytes}) from {src_addr}");
  94                     continue;
  95                 }
  96                 let message = Message::try_from(filled_buf).expect("I can't count");
  97                 log.serialize((&message.key, message.t))
  98                     .expect("Couldn't write log");
  99                 log.flush().expect("Couldn't flush log");
 100                 if let Some(r) = presses.get_mut(&message.key) {
 101                     if !r.contains(&message.t) {
 102                         r.extend(&message.t);
 103                     }
 104                 } else {
 105                     presses.insert(message.key, Range::new(&message.t));
 106                 }
 107             }
 108         }
 109     }
 110 }