lib: set uplink flag for NAS

EFForg · Jan 30, 2025 · 5a084f1 · 5a084f1
1 parent 3619df3
commit 5a084f1
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Showing 3 changed files with 13 additions and 6 deletions.
diff --git a/lib/src/diag.rs b/lib/src/diag.rs
@@ -221,9 +221,9 @@ pub enum Nas4GMessageDirection {
     // * 0xb0ec: plain EMM NAS message (incoming)
     // * 0xb0ed: plain EMM NAS message (outgoing)
     #[deku(id_pat = "0xb0e2 | 0xb0ec")]
-    Inbound,
+    Downlink,
     #[deku(id_pat = "0xb0e3 | 0xb0ed")]
-    Outbound,
+    Uplink,
 }
 
 #[derive(Debug, Clone, PartialEq, DekuRead, DekuWrite)]

diff --git a/lib/src/gsmtap.rs b/lib/src/gsmtap.rs
@@ -17,7 +17,7 @@ pub enum GsmtapType {
     UmtsRlcMac,
     UmtsRrc(UmtsRrcSubtype),
     LteRrc(LteRrcSubtype), /* LTE interface */
-    LteMac, /* LTE MAC interface */ 
+    LteMac, /* LTE MAC interface */
     LteMacFramed, /* LTE MAC with context hdr */
     OsmocoreLog, /* libosmocore logging */
     QcDiag, /* Qualcomm DIAG frame */
@@ -200,6 +200,11 @@ pub struct GsmtapHeader {
     #[deku(update = "self.gsmtap_type.get_type()")]
     pub packet_type: u8,
     pub timeslot: u8,
+    #[deku(bits = 1)]
+    pub pcs_band_indicator: bool,
+    #[deku(bits = 1)]
+    pub uplink: bool,
+    #[deku(bits = 14)]
     pub arfcn: u16,
     pub signal_dbm: i8,
     pub signal_noise_ratio_db: u8,
@@ -222,6 +227,8 @@ impl GsmtapHeader {
             header_len: 4,
             packet_type: gsmtap_type.get_type(),
             timeslot: 0,
+            pcs_band_indicator: false,
+            uplink: false,
             arfcn: 0,
             signal_dbm: 0,
             signal_noise_ratio_db: 0,

diff --git a/lib/src/gsmtap_parser.rs b/lib/src/gsmtap_parser.rs
@@ -99,7 +99,6 @@ fn log_to_gsmtap(value: LogBody) -> Result<Option<GsmtapMessage>, GsmtapParserEr
                 _ => return Err(GsmtapParserError::InvalidLteRrcOtaExtHeaderVersion(ext_header_version)),
             };
             let mut header = GsmtapHeader::new(gsmtap_type);
-            // Wireshark GSMTAP only accepts 14 bits of ARFCN
             header.arfcn = packet.get_earfcn().try_into().unwrap_or(0);
             header.frame_number = packet.get_sfn();
             header.subslot = packet.get_subfn();
@@ -108,9 +107,10 @@ fn log_to_gsmtap(value: LogBody) -> Result<Option<GsmtapMessage>, GsmtapParserEr
                 payload: packet.take_payload(),
             }))
         },
-        LogBody::Nas4GMessage { msg, .. } => {
+        LogBody::Nas4GMessage { msg, direction, .. } => {
             // currently we only handle "plain" (i.e. non-secure) NAS messages
-            let header = GsmtapHeader::new(GsmtapType::LteNas(LteNasSubtype::Plain));
+            let mut header = GsmtapHeader::new(GsmtapType::LteNas(LteNasSubtype::Plain));
+            header.uplink = matches!(direction,  Nas4GMessageDirection::Uplink);
             Ok(Some(GsmtapMessage {
                 header,
                 payload: msg,