scan: Add support of query scan results

Work was based on #9 by
Rayzeq.

Introduce `Nl80211ScanHandle::dump()` equal to
`iw dev DEVICE scan dump`.

Example code included as `examples/dump_nl80211_scan.rs`

Signed-off-by: Gris Ge <[email protected]>

examples/dump_nl80211_scan.rs

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+
+use std::env::args;
+
+use anyhow::{bail, Context, Error};
+use futures::stream::TryStreamExt;
+
+fn main() -> Result<(), Error> {
+    let argv: Vec<_> = args().collect();
+
+    if argv.len() < 2 {
+        eprintln!("Usage: dump_nl80211_scan <interface index>");
+        bail!("Required arguments not given");
+    }
+
+    let err_msg = format!("Invalid interface index value: {}", argv[1]);
+    let index = argv[1].parse::<u32>().context(err_msg)?;
+
+    let rt = tokio::runtime::Builder::new_current_thread()
+        .enable_io()
+        .build()
+        .unwrap();
+    rt.block_on(dump_scan(index));
+
+    Ok(())
+}
+
+async fn dump_scan(if_index: u32) {
+    let (connection, handle, _) = wl_nl80211::new_connection().unwrap();
+    tokio::spawn(connection);
+
+    let mut scan_handle = handle.scan().dump(if_index).execute().await;
+
+    let mut msgs = Vec::new();
+    while let Some(msg) = scan_handle.try_next().await.unwrap() {
+        msgs.push(msg);
+    }
+    assert!(!msgs.is_empty());
+    for msg in msgs {
+        println!("{:?}", msg);
+    }
+}

src/attr.rs

@@ -39,8 +39,8 @@ use netlink_packet_utils::{
 use crate::{
     bytes::{write_u16, write_u32, write_u64},
     wiphy::Nl80211Commands,
-    Nl80211Band, Nl80211BandTypes, Nl80211ChannelWidth, Nl80211CipherSuit,
-    Nl80211Command, Nl80211ExtFeature, Nl80211ExtFeatures,
+    Nl80211Band, Nl80211BandTypes, Nl80211BssInfo, Nl80211ChannelWidth,
+    Nl80211CipherSuit, Nl80211Command, Nl80211ExtFeature, Nl80211ExtFeatures,
     Nl80211ExtendedCapability, Nl80211Features, Nl80211HtCapabilityMask,
     Nl80211HtWiphyChannelType, Nl80211IfMode, Nl80211IfTypeExtCapa,
     Nl80211IfTypeExtCapas, Nl80211IfaceComb, Nl80211IfaceFrameType,
@@ -163,7 +163,7 @@ const NL80211_ATTR_MAX_NUM_SCAN_SSIDS: u16 = 43;
 // const NL80211_ATTR_SCAN_FREQUENCIES:u16 = 44;
 // const NL80211_ATTR_SCAN_SSIDS:u16 = 45;
 const NL80211_ATTR_GENERATION: u16 = 46;
-// const NL80211_ATTR_BSS:u16 = 47;
+const NL80211_ATTR_BSS: u16 = 47;
 // const NL80211_ATTR_REG_INITIATOR:u16 = 48;
 // const NL80211_ATTR_REG_TYPE:u16 = 49;
 const NL80211_ATTR_SUPPORTED_COMMANDS: u16 = 50;
@@ -544,6 +544,8 @@ pub enum Nl80211Attr {
     /// not specifying an address with set hardware timestamp) is
     /// supported.
     MaxHwTimestampPeers(u16),
+    /// Basic Service Set (BSS)
+    Bss(Vec<Nl80211BssInfo>),
     Other(DefaultNla),
 }
 
@@ -633,6 +635,7 @@ impl Nla for Nl80211Attr {
             | Self::MaxNumAkmSuites(_)
             | Self::MaxHwTimestampPeers(_) => 2,
             Self::Bands(_) => Nl80211BandTypes::LENGTH,
+            Self::Bss(v) => v.as_slice().buffer_len(),
             Self::Other(attr) => attr.value_len(),
         }
     }
@@ -729,6 +732,7 @@ impl Nla for Nl80211Attr {
             Self::Bands(_) => NL80211_ATTR_BANDS,
             Self::MaxNumAkmSuites(_) => NL80211_ATTR_MAX_NUM_AKM_SUITES,
             Self::MaxHwTimestampPeers(_) => NL80211_ATTR_MAX_HW_TIMESTAMP_PEERS,
+            Self::Bss(_) => NL80211_ATTR_BSS,
             Self::Other(attr) => attr.kind(),
         }
     }
@@ -832,6 +836,7 @@ impl Nla for Nl80211Attr {
             | Self::MaxNumAkmSuites(d)
             | Self::MaxHwTimestampPeers(d) => write_u16(buffer, *d),
             Self::Bands(v) => v.emit(buffer),
+            Self::Bss(v) => v.as_slice().emit(buffer),
             Self::Other(attr) => attr.emit(buffer),
         }
     }
@@ -892,6 +897,16 @@ impl<'a, T: AsRef<[u8]> + ?Sized> Parseable<NlaBuffer<&'a T>> for Nl80211Attr {
                 );
                 Self::Generation(parse_u32(payload).context(err_msg)?)
             }
+            NL80211_ATTR_BSS => {
+                let err_msg =
+                    format!("Invalid NL80211_ATTR_BSS value {:?}", payload);
+                let mut nlas = Vec::new();
+                for nla in NlasIterator::new(payload) {
+                    let nla = &nla.context(err_msg.clone())?;
+                    nlas.push(Nl80211BssInfo::parse(nla)?);
+                }
+                Self::Bss(nlas)
+            }
             NL80211_ATTR_4ADDR => {
                 let err_msg =
                     format!("Invalid NL80211_ATTR_4ADDR value {:?}", payload);

src/bytes.rs

@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+use netlink_packet_utils::DecodeError;
+
 pub(crate) fn write_u16(buffer: &mut [u8], value: u16) {
     buffer[..2].copy_from_slice(&value.to_ne_bytes())
 }
@@ -12,10 +14,18 @@ pub(crate) fn write_u32(buffer: &mut [u8], value: u32) {
     buffer[..4].copy_from_slice(&value.to_ne_bytes())
 }
 
+pub(crate) fn write_u32_le(buffer: &mut [u8], value: u32) {
+    buffer[..4].copy_from_slice(&value.to_le_bytes())
+}
+
 pub(crate) fn write_u64(buffer: &mut [u8], value: u64) {
     buffer[..8].copy_from_slice(&value.to_ne_bytes())
 }
 
+pub(crate) fn write_i32(buffer: &mut [u8], value: i32) {
+    buffer[..4].copy_from_slice(&value.to_ne_bytes())
+}
+
 pub(crate) fn get_bit(data: &[u8], pos: usize) -> bool {
     let index: usize = pos / 8;
     let bit_pos: usize = pos % 8;
@@ -44,3 +54,10 @@ pub(crate) fn get_bits_as_u8(data: &[u8], start: usize, end: usize) -> u8 {
     }
     ret
 }
+
+pub(crate) fn parse_u16_le(payload: &[u8]) -> Result<u16, DecodeError> {
+    if payload.len() < 2 {
+        return Err(format!("Invalid payload for u16: {:?}", payload).into());
+    }
+    Ok(u16::from_le_bytes([payload[0], payload[1]]))
+}