From f8581559e7d24a314692538bb2864fc3f5cc21ee Mon Sep 17 00:00:00 2001
From: Will Greenberg <willg@eff.org>
Date: Wed, 30 Jul 2025 15:43:02 -0700
Subject: [PATCH] lib: add diag parsing for LTE MAC DL packets

---
 lib/src/diag.rs          | 17 +++++++++++++++++
 lib/src/diag_device.rs   | 27 +++++++++++++++------------
 lib/src/gsmtap_parser.rs | 17 +++++++----------
 lib/src/log_codes.rs     |  3 +++
 4 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/lib/src/diag.rs b/lib/src/diag.rs
index fcdb33b..2a0eeb0 100644
--- a/lib/src/diag.rs
+++ b/lib/src/diag.rs
@@ -210,6 +210,14 @@ pub enum LogBody {
         #[deku(count = "hdr_len.saturating_sub(8)")]
         msg: Vec<u8>,
     },
+    #[deku(id = "0xb063")]
+    LteMacDl {
+        version: u8,
+        #[deku(pad_bytes_after = "2")]
+        num_subpacket: u8,
+        #[deku(count = "num_subpacket")]
+        subpackets: Vec<LteMacDlSubpacket>,
+    },
     #[deku(id = "0x713a")]
     UmtsNasOtaMessage {
         is_uplink: u8,
@@ -224,6 +232,15 @@ pub enum LogBody {
     },
 }
 
+#[derive(Debug, Clone, PartialEq, DekuRead, DekuWrite)]
+pub struct LteMacDlSubpacket {
+    pub id: u8,
+    pub version: u8,
+    pub size: u16,
+    #[deku(count = "size - 4")]
+    pub data: Vec<u8>,
+}
+
 #[derive(Debug, Clone, PartialEq, DekuRead, DekuWrite)]
 #[deku(ctx = "log_type: u16", id = "log_type")]
 pub enum Nas4GMessageDirection {
diff --git a/lib/src/diag_device.rs b/lib/src/diag_device.rs
index 47aa496..bbca03a 100644
--- a/lib/src/diag_device.rs
+++ b/lib/src/diag_device.rs
@@ -40,22 +40,25 @@ pub enum DiagDeviceError {
     ParseMessagesContainerError(deku::DekuError),
 }
 
-pub const LOG_CODES_FOR_RAW_PACKET_LOGGING: [u32; 11] = [
+pub const LOG_CODES_FOR_RAW_PACKET_LOGGING: [u32; 13] = [
     // Layer 2:
-    log_codes::LOG_GPRS_MAC_SIGNALLING_MESSAGE_C, // 0x5226
+    log_codes::LOG_GPRS_MAC_SIGNALLING_MESSAGE_C,
     // Layer 3:
-    log_codes::LOG_GSM_RR_SIGNALING_MESSAGE_C, // 0x512f
-    log_codes::WCDMA_SIGNALLING_MESSAGE,       // 0x412f
-    log_codes::LOG_LTE_RRC_OTA_MSG_LOG_C,      // 0xb0c0
-    log_codes::LOG_NR_RRC_OTA_MSG_LOG_C,       // 0xb821
+    log_codes::LOG_GSM_RR_SIGNALING_MESSAGE_C,
+    log_codes::WCDMA_SIGNALLING_MESSAGE,
+    log_codes::LOG_LTE_RRC_OTA_MSG_LOG_C,
+    log_codes::LOG_NR_RRC_OTA_MSG_LOG_C,
     // NAS:
-    log_codes::LOG_UMTS_NAS_OTA_MESSAGE_LOG_PACKET_C, // 0x713a
-    log_codes::LOG_LTE_NAS_ESM_OTA_IN_MSG_LOG_C,      // 0xb0e2
-    log_codes::LOG_LTE_NAS_ESM_OTA_OUT_MSG_LOG_C,     // 0xb0e3
-    log_codes::LOG_LTE_NAS_EMM_OTA_IN_MSG_LOG_C,      // 0xb0ec
-    log_codes::LOG_LTE_NAS_EMM_OTA_OUT_MSG_LOG_C,     // 0xb0ed
+    log_codes::LOG_UMTS_NAS_OTA_MESSAGE_LOG_PACKET_C,
+    log_codes::LOG_LTE_NAS_ESM_OTA_IN_MSG_LOG_C,
+    log_codes::LOG_LTE_NAS_ESM_OTA_OUT_MSG_LOG_C,
+    log_codes::LOG_LTE_NAS_EMM_OTA_IN_MSG_LOG_C,
+    log_codes::LOG_LTE_NAS_EMM_OTA_OUT_MSG_LOG_C,
+    // MAC
+    log_codes::LOG_LTE_MAC_DL,
+    log_codes::LOG_LTE_MAC_UL,
     // User IP traffic:
-    log_codes::LOG_DATA_PROTOCOL_LOGGING_C, // 0x11eb
+    log_codes::LOG_DATA_PROTOCOL_LOGGING_C,
 ];
 
 const BUFFER_LEN: usize = 1024 * 1024 * 10;
diff --git a/lib/src/gsmtap_parser.rs b/lib/src/gsmtap_parser.rs
index b258626..4a7ea58 100644
--- a/lib/src/gsmtap_parser.rs
+++ b/lib/src/gsmtap_parser.rs
@@ -13,16 +13,13 @@ pub enum GsmtapParserError {
 }
 
 pub fn parse(msg: Message) -> Result<Option<(Timestamp, GsmtapMessage)>, GsmtapParserError> {
-    if let Message::Log {
-        timestamp, body, ..
-    } = msg
-    {
-        match log_to_gsmtap(body)? {
-            Some(msg) => Ok(Some((timestamp, msg))),
-            None => Ok(None),
-        }
-    } else {
-        Ok(None)
+    let Message::Log { timestamp, body, .. } = msg else {
+        return Ok(None);
+    };
+
+    match log_to_gsmtap(body)? {
+        Some(msg) => Ok(Some((timestamp, msg))),
+        None => Ok(None),
     }
 }
 
diff --git a/lib/src/log_codes.rs b/lib/src/log_codes.rs
index b337e99..f9a47f3 100644
--- a/lib/src/log_codes.rs
+++ b/lib/src/log_codes.rs
@@ -36,6 +36,9 @@ pub const LOG_LTE_NAS_ESM_OTA_OUT_MSG_LOG_C: u32 = 0xb0e3;
 pub const LOG_LTE_NAS_EMM_OTA_IN_MSG_LOG_C: u32 = 0xb0ec;
 pub const LOG_LTE_NAS_EMM_OTA_OUT_MSG_LOG_C: u32 = 0xb0ed;
 
+pub const LOG_LTE_MAC_DL: u32 = 0xb063;
+pub const LOG_LTE_MAC_UL: u32 = 0xb064;
+
 pub const LTE_BCCH_BCH_V0: u32 = 1;
 pub const LTE_BCCH_DL_SCH_V0: u32 = 2;
 pub const LTE_MCCH_V0: u32 = 3;