From 45dfbd6d6674f0691d76bc1193a5750b76095d04 Mon Sep 17 00:00:00 2001
From: Alon Levy <alon@pobox.com>
Date: Fri, 29 Dec 2023 02:22:07 +0200
Subject: [PATCH] gets frames

---
 thermalcamdecoder/Cargo.lock  | 21 ++++++++++
 thermalcamdecoder/Cargo.toml  |  1 +
 thermalcamdecoder/src/main.rs | 72 ++++++++++++++++++++++++++++++++++-
 3 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/thermalcamdecoder/Cargo.lock b/thermalcamdecoder/Cargo.lock
index 76ab780..051e686 100644
--- a/thermalcamdecoder/Cargo.lock
+++ b/thermalcamdecoder/Cargo.lock
@@ -234,6 +234,26 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "serde"
+version = "1.0.193"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25dd9975e68d0cb5aa1120c288333fc98731bd1dd12f561e468ea4728c042b89"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.193"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43576ca501357b9b071ac53cdc7da8ef0cbd9493d8df094cd821777ea6e894d3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "smallvec"
 version = "1.11.2"
@@ -264,6 +284,7 @@ dependencies = [
  "anyhow",
  "pcap-parser",
  "pyo3",
+ "serde",
 ]
 
 [[package]]
diff --git a/thermalcamdecoder/Cargo.toml b/thermalcamdecoder/Cargo.toml
index a5ecd55..ca3dac9 100644
--- a/thermalcamdecoder/Cargo.toml
+++ b/thermalcamdecoder/Cargo.toml
@@ -9,3 +9,4 @@ edition = "2021"
 anyhow = "1.0.77"
 pcap-parser = { version = "0.14.1", features = ["data"] }
 pyo3 = "0.20.0"
+serde = { version = "1.0.193", features = ["derive", "serde_derive", "alloc"] }
diff --git a/thermalcamdecoder/src/main.rs b/thermalcamdecoder/src/main.rs
index add8422..66861eb 100644
--- a/thermalcamdecoder/src/main.rs
+++ b/thermalcamdecoder/src/main.rs
@@ -1,9 +1,10 @@
 use std::fs::File;
+use std::io::Write;
 
 use pcap_parser::traits::PcapReaderIterator;
 use pcap_parser::*;
 
-fn main() -> anyhow::Result<()> {
+fn get_packets_without_udp_header() -> anyhow::Result<(Vec<Vec<u8>>, usize, usize)> {
     let file = File::open("in.pcap")?;
     let mut cap = PcapNGReader::new(65535, file)?;
     let mut i = 0;
@@ -54,7 +55,74 @@ fn main() -> anyhow::Result<()> {
             }
         }
     }
+    Ok((data, i, size))
+}
+
+#[repr(C, packed)]
+#[derive(Clone, Debug)]
+struct Header {
+    c1: u32,
+    c2: u16,
+    part: u16,
+    a: u16,
+    ffaa: u16,
+    b: u16,
+    c: u16,
+    d: u16,
+}
+
+impl Header {
+    fn read(data: &[u8]) -> anyhow::Result<Self> {
+        Ok(Header {
+            c1: u32::from_be_bytes([data[0], data[1], data[2], data[3]]),
+            c2: u16::from_be_bytes([data[4], data[5]]),
+            part: u16::from_be_bytes([data[6], data[7]]),
+            a: u16::from_be_bytes([data[8], data[9]]),
+            ffaa: u16::from_be_bytes([data[10], data[11]]),
+            b: u16::from_be_bytes([data[12], data[13]]),
+            c: u16::from_be_bytes([data[14], data[15]]),
+            d: u16::from_be_bytes([data[16], data[17]]),
+        })
+    }
+
+    fn read_via_cast(data: &[u8]) -> anyhow::Result<&Self> {
+        let size = std::mem::size_of::<Self>();
+        if data.len() < size {
+            return Err(anyhow::anyhow!("not large enough"));
+        }
+        let mem = &data[..size].as_ptr();
+        Ok(unsafe { &*mem.cast() })
+    }
+}
+
+const HDR_SIZE: usize = std::mem::size_of::<Header>();
+
+fn main() -> anyhow::Result<()> {
+    let (data, i, size) = get_packets_without_udp_header()?;
+
     println!("found {} packets, saved {}, {} size", i, data.len(), size);
-    println!("{:+?}", data);
+    let mut dump = File::create_new("dump.bin");
+    let mut frames = vec![];
+    let mut parts = None;
+    for packet in data.iter() {
+        if let Ok(ref mut dump) = dump {
+            dump.write_all(&packet);
+        }
+        let hdr = Header::read(packet)?;
+        let data = packet[HDR_SIZE..].to_vec();
+        match parts {
+            None => {
+                parts = Some(vec![data]);
+            }
+            Some(ref mut v) => {
+                v.push(data);
+                if hdr.part == 0 {
+                    frames.push(parts.take());
+                }
+            }
+        }
+    }
+    println!("found {} frames", frames.len());
+
     Ok(())
 }