From c4249025606c3370c1b0a025df0077c78692db64 Mon Sep 17 00:00:00 2001
From: Carlos Guerra <cguerrave@gmail.com>
Date: Sun, 31 May 2026 15:54:22 +0200
Subject: [PATCH] linting and polishing for PR

---
 lib/src/diag/diaglog/measurement.rs | 28 +++++++++------
 lib/src/gsmtap/parser.rs            | 54 +++++++++++++++++++++++++++--
 2 files changed, 70 insertions(+), 12 deletions(-)

diff --git a/lib/src/diag/diaglog/measurement.rs b/lib/src/diag/diaglog/measurement.rs
index 9b0c494..9a70502 100644
--- a/lib/src/diag/diaglog/measurement.rs
+++ b/lib/src/diag/diaglog/measurement.rs
@@ -77,23 +77,31 @@ mod test {
         // Constructed as: opcode(1) + pending(1) + outer_len(2) + inner_len(2) +
         //                 log_type(2=0xb17f LE) + timestamp(8) + body(40) = 56 bytes total
         let mut msg_bytes: Vec<u8> = vec![
-            0x10, 0x00,             // opcode=Log, pending=0
-            56, 0, 56, 0,           // outer_length=56, inner_length=56
-            0x7f, 0xb1,             // log_type = 0xb17f (LE)
+            0x10, 0x00, // opcode=Log, pending=0
+            56, 0, 56, 0, // outer_length=56, inner_length=56
+            0x7f, 0xb1, // log_type = 0xb17f (LE)
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // timestamp
         ];
         msg_bytes.extend_from_slice(&[
             0x05, // version=5
-            0x01, 0x00, 0x00, 0x39, 0x07, 0x00, 0x00, 0x89, 0x00, 0x00, 0x00,
-            0xab, 0xb5, 0x5a, 0x00, 0xab, 0xb5, 0x5a, 0x00,
-            0x1a, 0x69, 0xa4, 0x11, 0x1a, 0x45, 0x0d, 0x00, 0x86, 0xa7, 0xae, 0x02,
-            0x00, 0x00, 0x00, 0x00, 0x80, 0x1c, 0x00, 0x00,
+            0x01, 0x00, 0x00, 0x39, 0x07, 0x00, 0x00, 0x89, 0x00, 0x00, 0x00, 0xab, 0xb5, 0x5a,
+            0x00, 0xab, 0xb5, 0x5a, 0x00, 0x1a, 0x69, 0xa4, 0x11, 0x1a, 0x45, 0x0d, 0x00, 0x86,
+            0xa7, 0xae, 0x02, 0x00, 0x00, 0x00, 0x00, 0x80, 0x1c, 0x00, 0x00,
         ]);
-        let msg = Message::from_bytes((&msg_bytes, 0)).expect("Message parse failed").1;
-        if let Message::Log { body: LogBody::LteMl1ServingCellMeas { packet, .. }, .. } = msg {
+        let msg = Message::from_bytes((&msg_bytes, 0))
+            .expect("Message parse failed")
+            .1;
+        if let Message::Log {
+            body: LogBody::LteMl1ServingCellMeas { packet, .. },
+            ..
+        } = msg
+        {
             assert_eq!(packet.get_earfcn(), 1849);
             let rsrp = packet.get_rsrp_dbm();
-            assert!(rsrp <= -44 && rsrp >= -120, "RSRP {rsrp} dBm outside valid LTE range");
+            assert!(
+                rsrp <= -44 && rsrp >= -120,
+                "RSRP {rsrp} dBm outside valid LTE range"
+            );
         } else {
             panic!("unexpected message variant");
         }
diff --git a/lib/src/gsmtap/parser.rs b/lib/src/gsmtap/parser.rs
index b45a12d..bc1e3ba 100644
--- a/lib/src/gsmtap/parser.rs
+++ b/lib/src/gsmtap/parser.rs
@@ -201,7 +201,8 @@ fn parse_rach_response(payload: &[u8]) -> Option<GsmtapMessage> {
 
         if sp_id == 0x06 {
             // RACH Attempt subpacket
-            if let Some(msg) = extract_rach_attempt_gsmtap(&payload[offset + 4..sp_end], sp_version) {
+            if let Some(msg) = extract_rach_attempt_gsmtap(&payload[offset + 4..sp_end], sp_version)
+            {
                 return Some(msg);
             }
         }
@@ -258,7 +259,10 @@ fn extract_rach_attempt_gsmtap(body: &[u8], version: u8) -> Option<GsmtapMessage
     // RA-RNTI (type=2) and applies the RAR PDU format. The 4-byte framing prefix is:
     //   [RadioType=1(FDD)][Direction=1(DL)][RNTIType=2(RA-RNTI)][0x01=payload-marker]
     let payload = vec![
-        0x01u8, 0x01, 0x02, 0x01, // framing: FDD, DL, RA-RNTI, payload-marker
+        0x01u8,
+        0x01,
+        0x02,
+        0x01, // framing: FDD, DL, RA-RNTI, payload-marker
         rapid & 0x3F,
         ((ta >> 3) & 0xFF) as u8,
         ((ta & 0x07) as u8) << 5,
@@ -278,6 +282,7 @@ fn extract_rach_attempt_gsmtap(body: &[u8], version: u8) -> Option<GsmtapMessage
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::gsmtap::GsmtapType;
     use deku::DekuContainerWrite;
 
     #[test]
@@ -293,4 +298,49 @@ mod tests {
         // This would panic before the fix with "bit size of input is larger than bit requested size"
         assert!(msg.to_bytes().is_ok());
     }
+
+    // Builds a minimal 0xb062 payload: outer header + one RACH Attempt subpacket (version 0x03).
+    // v0x03 body layout: hdr=6B [_, _, rapid, _, _, bitmask], then MSG2=7B [backoff(2), result(1), tc_rnti(2), ta(2)]
+    fn make_rach_v03_payload(ta_raw: u16, bitmask: u8) -> Vec<u8> {
+        let rapid: u8 = 43;
+        let tc_rnti: u16 = 0x1234;
+        let [ta_lo, ta_hi] = ta_raw.to_le_bytes();
+        let [rnti_lo, rnti_hi] = tc_rnti.to_le_bytes();
+        // sp_size covers the 4-byte subpacket header + 6-byte body header + 7-byte MSG2 = 17
+        vec![
+            0x01, 0x01, 0x00, 0x00, // outer: version=1, num_subpackets=1, reserved
+            0x06, 0x03, 17, 0x00, // subpacket: id=0x06, version=0x03, size=17 LE
+            0x00, 0x00, rapid, 0x00, 0x00, bitmask, // body header (6 bytes)
+            0x00, 0x00, 0x01, rnti_lo, rnti_hi, ta_lo, ta_hi, // MSG2 (7 bytes)
+        ]
+    }
+
+    #[test]
+    fn test_rach_response_valid_ta() {
+        let payload = make_rach_v03_payload(42, 0x02); // 0x02 = msg2 present, msg1 absent
+        let msg = parse_rach_response(&payload).expect("expected a GsmtapMessage for valid TA");
+        assert_eq!(msg.header.gsmtap_type, GsmtapType::LteMacFramed);
+        // TA stored in frame_number for Wireshark compatibility (gsmtap.frame_nr)
+        assert_eq!(msg.header.frame_number, 42);
+        // MAC RAR PDU: 4-byte framing prefix + 7-byte RAR PDU = 11 bytes
+        assert_eq!(msg.payload.len(), 11);
+        // Verify TA encoding in RAR PDU bytes 5–6 (TA[10:3] and TA[2:0])
+        // ta=42: ta>>3=5 in byte[5], (ta&7)<<5 = 2<<5 = 0x40 in byte[6]
+        assert_eq!(msg.payload[5], 5);
+        assert_eq!(msg.payload[6], 0x40);
+    }
+
+    #[test]
+    fn test_rach_response_ffff_sentinel_returns_none() {
+        // 0xFFFF means RAR was received but TA was not valid; must be dropped
+        let payload = make_rach_v03_payload(0xFFFF, 0x02);
+        assert!(parse_rach_response(&payload).is_none());
+    }
+
+    #[test]
+    fn test_rach_response_no_msg2_returns_none() {
+        // bitmask=0x01 means only MSG1 present; no TA available
+        let payload = make_rach_v03_payload(42, 0x01);
+        assert!(parse_rach_response(&payload).is_none());
+    }
 }