Forgot to add Ok(())

src/main.rs

@@ -1,7 +1,7 @@
 use clap::Parser;
 use std::{
     fs::File,
-    io,
+    io::{self, IsTerminal},
     path::{Path, PathBuf},
     sync::mpsc::{channel, Sender},
     thread,
@@ -10,7 +10,7 @@ use std::{
 use anyhow::Result;
 use ax25::frame::Ax25Frame;
 use pcap_file::{
-    pcap::{PcapHeader, PcapPacket, PcapWriter},
+    pcap::{PcapHeader, PcapPacket, PcapReader, PcapWriter},
     DataLink,
 };
 use std::io::Read;
@@ -28,6 +28,18 @@ struct KissPkt {
     data: Vec<u8>,
 }
 
+fn pcap_loop<T: Read>(tx: Sender<KissPkt>, stream: T) -> Result<()> {
+    let mut reader = PcapReader::new(stream)?;
+
+    while let Some(Ok(pkt)) = reader.next_packet() {
+        tx.send(KissPkt {
+            timestamp: pkt.timestamp,
+            orig_len: pkt.orig_len,
+            data: pkt.data.into(),
+        })?;
+    }
+    Ok(())
+}
 fn tnc_loop<T: Read>(tx: Sender<KissPkt>, mut stream: T) -> Result<()> {
     let mut buffer = [0_u8; 4096];
     let mut frame = vec![];
@@ -110,8 +122,14 @@ fn main() -> Result<()> {
             thread::spawn(move || tnc_loop(tx, file).unwrap());
         }
         path if Path::new(path).exists() => {
-            let file = io::BufReader::new(File::open(path)?);
-            thread::spawn(move || tnc_loop(tx, file).unwrap());
+            let file = File::open(path)?;
+            let is_tty = file.is_terminal();
+            let mut filebuf = io::BufReader::new(file);
+            if !is_tty && has_pcap_magic(&mut filebuf) {
+                thread::spawn(move || pcap_loop(tx, filebuf).unwrap());
+            } else {
+                thread::spawn(move || tnc_loop(tx, filebuf).unwrap());
+            }
         }
         addr => {
             let stream = TcpStream::connect(addr)?;
@@ -155,3 +173,17 @@ fn main() -> Result<()> {
 
     Ok(())
 }
+fn has_pcap_magic(filebuf: &mut io::BufReader<File>) -> bool {
+    const PCAP_MAGIC_MS: u32 = 0xA1B2C3D4;
+    const PCAP_MAGIC_NS: u32 = 0xA1B23C4D;
+    match io::BufRead::fill_buf(filebuf) {
+        Ok(buf) if buf.len() >= 4 => {
+            let mut tmp = [0_u8; 4];
+            tmp.copy_from_slice(&buf[..4]);
+            let be = u32::from_be_bytes(tmp);
+            let le = u32::from_le_bytes(tmp);
+            be == PCAP_MAGIC_MS || be == PCAP_MAGIC_NS || le == PCAP_MAGIC_MS || le == PCAP_MAGIC_NS
+        }
+        _ => false,
+    }
+}