fix packet reading and leftover bytes checks

src/diag.rs

@@ -1,7 +1,7 @@
 //! Diag protocol serialization/deserialization
 
 use chrono::{DateTime, FixedOffset};
-use deku::{prelude::*, bitvec::{BitSlice, Msb0}};
+use deku::prelude::*;
 
 #[derive(Debug, Clone, DekuWrite)]
 pub struct RequestContainer {
@@ -148,28 +148,6 @@ pub enum LogBody {
     }
 }
 
-/*
-        item_struct = namedtuple('QcDiagLteRrcOtaPacket', 'rrc_rel_maj rrc_rel_min rbid pci earfcn sfn_subfn pdu_num len')
-        item_struct_v5 = namedtuple('QcDiagLteRrcOtaPacketV5', 'rrc_rel_maj rrc_rel_min rbid pci earfcn sfn_subfn pdu_num sib_mask len')
-        item_struct_v25 = namedtuple('QcDiagLteRrcOtaPacketV25', 'rrc_rel_maj rrc_rel_min nr_rrc_rel_maj nr_rrc_rel_min rbid pci earfcn sfn_subfn pdu_num sib_mask len')
-        if pkt_version >= 25:
-            # Version 25, 26, 27
-            item = item_struct_v25._make(struct.unpack('<BBBB BHLH BLH', pkt_body[1:21]))
-            msg_content = pkt_body[21:]
-        elif pkt_version >= 8:
-            # Version 8, 9, 12, 13, 15, 16, 19, 20, 22, 24
-            item = item_struct_v5._make(struct.unpack('<BB BHLH BLH', pkt_body[1:19]))
-            msg_content = pkt_body[19:]
-        elif pkt_version >= 5:
-            # Version 6, 7
-            item = item_struct_v5._make(struct.unpack('<BB BHHH BLH', pkt_body[1:17]))
-            msg_content = pkt_body[17:]
-        else:
-            # Version 2, 3, 4
-            item = item_struct._make(struct.unpack('<BB BHHH BH', pkt_body[1:13]))
-            msg_content = pkt_body[13:]
-*/
-
 #[derive(Debug, Clone, PartialEq, DekuRead)]
 #[deku(ctx = "ext_header_version: u8", id = "ext_header_version")]
 pub enum LteRrcOtaPacket {

src/diag_device.rs

@@ -63,7 +63,7 @@ pub const LOG_CODES_FOR_RAW_PACKET_LOGGING: [u32; 11] = [
     log_codes::LOG_DATA_PROTOCOL_LOGGING_C // 0x11eb
 ];
 
-const BUFFER_LEN: usize = 1024 * 1024 * 10;
+const BUFFER_LEN: usize = 1024 * 10;
 const MEMORY_DEVICE_MODE: i32 = 2;
 const DIAG_IOCTL_REMOTE_DEV: u32 = 32;
 const DIAG_IOCTL_SWITCH_LOGGING: u32 = 7;
@@ -97,9 +97,9 @@ impl DiagDevice {
         for msg in container.messages {
             match hdlc_decapsulate(&msg.data, &self.crc) {
                 Ok(data) => match Message::from_bytes((&data, 0)) {
-                    Ok(((_, leftover_bytes), res)) => {
+                    Ok(((leftover_bytes, _), res)) => {
-                        if leftover_bytes > 0 {
+                        if leftover_bytes.len() > 0 {
-                            println!("warning: {} leftover bytes when parsing Message", leftover_bytes);
+                            println!("warning: {} leftover bytes when parsing Message", leftover_bytes.len());
                         }
                         result.push(res);
                     },
@@ -118,13 +118,20 @@ impl DiagDevice {
     }
 
     pub fn read_response(&mut self) -> DiagResult<Vec<Message>> {
-        let mut buf = vec![0; BUFFER_LEN];
+        let mut packet_buf = vec![0; BUFFER_LEN];
 
         loop {
-            let _ = self.file.read(&mut buf)?;
+            let mut packet = vec![];
-            let ((_, leftover_bytes), res_container) = MessagesContainer::from_bytes((&buf, 0))?;
+            while !packet.ends_with(&[0x7e]) {
-            if leftover_bytes > 0 {
+                let bytes_read = self.file.read(&mut packet_buf)?;
-                println!("warning: {} leftover bytes when parsing ResponseContainer", leftover_bytes);
+                packet.extend(&packet_buf[0..bytes_read]);
+                // clear out the buffer so we don't accidentally read stale data
+                packet_buf.clear();
+                packet_buf.resize(BUFFER_LEN, 0);
+            }
+            let ((leftover_bytes, _), res_container) = MessagesContainer::from_bytes((&packet, 0))?;
+            if leftover_bytes.len() > 0 {
+                println!("warning: {} leftover bytes when parsing ResponseContainer", leftover_bytes.len());
             }
             if res_container.data_type == DataType::UserSpace {
                 return self.parse_response_container(res_container);

src/hdlc.rs

@@ -4,7 +4,7 @@
 //! https://github.com/P1sec/QCSuper/blob/master/docs/The%20Diag%20protocol.md#the-diag-protocol-over-usb
 
 use crc::Crc;
-use bytes::{Buf, BufMut};
+use bytes::Buf;
 use thiserror::Error;
 
 #[derive(Debug, Error, PartialEq)]
@@ -45,7 +45,6 @@ pub fn hdlc_encapsulate(data: &[u8], crc: &Crc<u16>) -> Vec<u8> {
 }
 
 pub fn hdlc_decapsulate(data: &[u8], crc: &Crc<u16>) -> Result<Vec<u8>, HdlcError> {
-    // TODO: return errors instead of panicking
     if data.len() < 3 {
         return Err(HdlcError::TooShort);
     }