X-Git-Url: https://code.octet-stream.net/m17rt/blobdiff_plain/c3a031d9fa12f5fc9888838a4793e47512ad7326..3903e719137aba15d30dd58b8d917965ec602400:/m17core/src/tnc.rs diff --git a/m17core/src/tnc.rs b/m17core/src/tnc.rs index a7cbc53..b46958c 100644 --- a/m17core/src/tnc.rs +++ b/m17core/src/tnc.rs @@ -1,5 +1,7 @@ use crate::address::{Address, Callsign}; -use crate::kiss::{KissBuffer, KissFrame, PORT_PACKET_BASIC, PORT_PACKET_FULL, PORT_STREAM}; +use crate::kiss::{ + KissBuffer, KissCommand, KissFrame, PORT_PACKET_BASIC, PORT_PACKET_FULL, PORT_STREAM, +}; use crate::modem::ModulatorFrame; use crate::protocol::{ Frame, LichCollection, LsfFrame, Mode, PacketFrame, PacketFrameCounter, StreamFrame, @@ -66,6 +68,12 @@ pub struct SoftTnc { /// Should PTT be on right now? Polled by external ptt: bool, + + /// TxDelay raw value, number of 10ms units. We will optimistically start with default 0. + tx_delay: u8, + + /// This is a full duplex channel so we do not need to monitor DCD or use CSMA. Default false. + full_duplex: bool, } impl SoftTnc { @@ -87,11 +95,17 @@ impl SoftTnc { stream_curr: 0, stream_full: false, ptt: false, + tx_delay: 0, + full_duplex: false, } } /// Process an individual `Frame` that has been decoded by the modem. pub fn handle_frame(&mut self, frame: Frame) { + if self.ptt { + // Ignore self-decodes + return; + } match frame { Frame::Lsf(lsf) => { // A new LSF implies a clean slate. @@ -107,7 +121,10 @@ impl SoftTnc { Mode::Stream => { let kiss = KissFrame::new_stream_setup(&lsf.0).unwrap(); self.kiss_to_host(kiss); - self.state = State::RxStream(RxStreamState { lsf, index: 0 }); + self.state = State::RxStream(RxStreamState { + _lsf: lsf, + index: 0, + }); } } } @@ -129,7 +146,7 @@ impl SoftTnc { let start = 25 * rx.count; let end = start + payload_len; rx.packet[start..(start + payload_len)] - .copy_from_slice(&packet.payload); + .copy_from_slice(&packet.payload[0..payload_len]); // TODO: compatible packets should be sent on port 0 too let kiss = KissFrame::new_full_packet(&rx.lsf.0, &rx.packet[0..end]) @@ -176,7 +193,7 @@ impl SoftTnc { // TODO: avoid discarding the first data payload here // need a queue depth of 2 for outgoing kiss self.state = State::RxStream(RxStreamState { - lsf, + _lsf: lsf, index: stream.frame_number + 1, }); } @@ -200,14 +217,13 @@ impl SoftTnc { pub fn set_now(&mut self, now_samples: u64) { self.now = now_samples; - match self.state { - State::TxEndingAtTime(time) => { - if now_samples >= time { - self.ptt = false; - self.state = State::Idle; - } + // TODO: expose this to higher layer so we can schedule a precise delay + // rather than waiting for some soundcard I/O event + if let State::TxEndingAtTime(time) = self.state { + if now_samples >= time { + self.ptt = false; + self.state = State::Idle; } - _ => (), } } @@ -217,11 +233,8 @@ impl SoftTnc { pub fn set_tx_end_time(&mut self, in_samples: usize) { log::debug!("tnc has been told that tx will complete in {in_samples} samples"); - match self.state { - State::TxEnding => { - self.state = State::TxEndingAtTime(self.now + in_samples as u64); - } - _ => (), + if let State::TxEnding = self.state { + self.state = State::TxEndingAtTime(self.now + in_samples as u64); } } @@ -235,30 +248,36 @@ impl SoftTnc { } // We have something we might send if the channel is free - match self.next_csma_check { - None => { - if self.dcd { - self.next_csma_check = Some(self.now + 1920); - return None; - } else { - // channel is idle at the moment we get a frame to send - // go right ahead - } - } - Some(at_time) => { - if self.now < at_time { - return None; + + // TODO: Proper full duplex support + // A true full duplex TNC should be able to rx and tx concurrently, implying + // separate states. + if !self.full_duplex { + match self.next_csma_check { + None => { + if self.dcd { + self.next_csma_check = Some(self.now + 1920); + return None; + } else { + // channel is idle at the moment we get a frame to send + // go right ahead + } } - // 25% chance that we'll transmit this slot. - // Using self.now as random is probably fine so long as it's not being set in - // a lumpy manner. m17app's soundmodem should be fine. - // TODO: bring in prng to help in cases where `now` never ends in 0b11 - let p1_4 = (self.now & 3) == 3; - if !self.dcd || !p1_4 { - self.next_csma_check = Some(self.now + 1920); - return None; - } else { - self.next_csma_check = None; + Some(at_time) => { + if self.now < at_time { + return None; + } + // 25% chance that we'll transmit this slot. + // Using self.now as random is probably fine so long as it's not being set in + // a lumpy manner. m17app's soundmodem should be fine. + // TODO: bring in prng to help in cases where `now` never ends in 0b11 + let p1_4 = (self.now & 3) == 3; + if !self.dcd || !p1_4 { + self.next_csma_check = Some(self.now + 1920); + return None; + } else { + self.next_csma_check = None; + } } } } @@ -269,8 +288,9 @@ impl SoftTnc { self.state = State::TxPacket; } self.ptt = true; - // TODO: true txdelay - Some(ModulatorFrame::Preamble { tx_delay: 0 }) + Some(ModulatorFrame::Preamble { + tx_delay: self.tx_delay, + }) } State::TxStream => { if !self.stream_full && self.stream_next == self.stream_curr { @@ -348,6 +368,31 @@ impl SoftTnc { let Ok(port) = kiss_frame.port() else { continue; }; + let Ok(command) = kiss_frame.command() else { + continue; + }; + if port != PORT_PACKET_BASIC && port != PORT_PACKET_FULL && port != PORT_STREAM { + continue; + } + if command == KissCommand::TxDelay { + let mut new_delay = [0u8; 1]; + if kiss_frame.decode_payload(&mut new_delay) == Ok(1) { + self.tx_delay = new_delay[0]; + } + continue; + } + if command == KissCommand::FullDuplex { + let mut new_duplex = [0u8; 1]; + if kiss_frame.decode_payload(&mut new_duplex) == Ok(1) { + self.full_duplex = new_duplex[0] != 0; + } + continue; + } + if command != KissCommand::DataFrame { + // Not supporting any other settings yet + // TODO: allow adjusting P persistence parameter for CSMA + continue; + } if port == PORT_PACKET_BASIC { if self.packet_full { continue; @@ -362,7 +407,7 @@ impl SoftTnc { pending.app_data[len..len + 2].copy_from_slice(&packet_crc.to_be_bytes()); pending.app_data_len = len + 2; pending.lsf = Some(LsfFrame::new_packet( - &Address::Callsign(Callsign(b"M17RT-PKT".clone())), + &Address::Callsign(Callsign(*b"M17RT-PKT")), &Address::Broadcast, )); self.packet_queue[self.packet_next] = pending; @@ -389,7 +434,7 @@ impl SoftTnc { } pending.lsf = Some(lsf); let app_data_len = len - 30; - pending.app_data[0..app_data_len].copy_from_slice(&payload[30..]); + pending.app_data[0..app_data_len].copy_from_slice(&payload[30..len]); pending.app_data_len = app_data_len; self.packet_queue[self.packet_next] = pending; self.packet_next = (self.packet_next + 1) % 4; @@ -442,6 +487,12 @@ impl SoftTnc { } } +impl Default for SoftTnc { + fn default() -> Self { + Self::new() + } +} + #[derive(Debug, PartialEq, Eq, Clone)] pub enum SoftTncError { General(&'static str), @@ -453,6 +504,7 @@ struct OutgoingKiss { sent: usize, } +#[allow(clippy::large_enum_variant)] enum State { /// Nothing happening. We may have TX data queued but we won't act on it until CSMA opens up. Idle, @@ -489,7 +541,7 @@ struct RxAcquiringStreamState { struct RxStreamState { /// Track identifying information for this transmission so we can tell if it changes. - lsf: LsfFrame, + _lsf: LsfFrame, /// Expected next frame number. Allowed to skip values on RX, but not go backwards. index: u16, @@ -552,7 +604,7 @@ impl PendingPacket { ) }; let mut payload = [0u8; 25]; - payload.copy_from_slice( + payload[0..data_len].copy_from_slice( &self.app_data[self.app_data_transmitted..(self.app_data_transmitted + data_len)], ); self.app_data_transmitted += data_len;