24-linktype

Add support for setting and getting linktype. Closes #24

Author: dbcfd

src/config.rs

@@ -5,6 +5,7 @@ pub struct Config {
     max_packets_read: usize,
     snaplen: u32,
     buffer_size: u32,
+    datalink: Option<i32>,
     bpf: Option<String>,
     buffer_for: std::time::Duration,
     blocking: bool,
@@ -29,6 +30,15 @@ impl Config {
         self
     }
 
+    pub fn datalink(&self) -> &Option<i32> {
+        &self.datalink
+    }
+
+    pub fn with_datalink_type(&mut self, datalink: i32) -> &mut Self {
+        self.datalink = Some(datalink);
+        self
+    }
+
     pub fn buffer_size(&self) -> u32 {
         self.buffer_size
     }
@@ -69,6 +79,7 @@ impl Config {
         max_packets_read: usize,
         snaplen: u32,
         buffer_size: u32,
+        datalink: Option<i32>,
         bpf: Option<String>,
         buffer_for: std::time::Duration,
         blocking: bool,
@@ -77,6 +88,7 @@ impl Config {
             max_packets_read,
             snaplen,
             buffer_size,
+            datalink,
             bpf,
             buffer_for,
             blocking,
@@ -90,6 +102,7 @@ impl Default for Config {
             max_packets_read: 1000,
             snaplen: 65535,
             buffer_size: 16777216,
+            datalink: None,
             bpf: None,
             buffer_for: std::time::Duration::from_millis(100),
             blocking: false,

src/handle.rs

@@ -157,6 +157,23 @@ impl Handle {
         }
     }
 
+    pub fn set_datalink(&self, datalink: i32) -> Result<&Self, Error> {
+        if 0 != unsafe { pcap_sys::pcap_set_datalink(self.handle, datalink as _) } {
+            Err(pcap_util::convert_libpcap_error(self.handle))
+        } else {
+            Ok(self)
+        }
+    }
+
+    pub fn get_datalink(&self) -> Result<i32, Error> {
+        let r = unsafe { pcap_sys::pcap_datalink(self.handle) };
+        if r < 0 {
+            Err(pcap_util::convert_libpcap_error(self.handle))
+        } else {
+            Ok(r)
+        }
+    }
+
     pub fn compile_bpf(&self, bpf: &str) -> Result<Bpf, Error> {
         let mut bpf_program = pcap_sys::bpf_program {
             bf_len: 0,
@@ -297,6 +314,7 @@ mod tests {
 
         assert!(handle.is_ok());
     }
+
     #[test]
     fn open_dead() {
         let _ = env_logger::try_init();
@@ -305,6 +323,22 @@ mod tests {
 
         assert!(handle.is_ok());
     }
+
+    #[test]
+    fn set_datalink() {
+        let _ = env_logger::try_init();
+
+        let handle = Handle::dead(0, 0).unwrap();
+
+        assert_eq!(handle.get_datalink().unwrap(), 0);
+
+        let r = handle.set_datalink(108);
+
+        assert!(r.is_err());
+
+        assert!(format!("{:?}", r.err().unwrap()).contains("not one of the DLTs supported"));
+    }
+
     #[test]
     fn bpf_compile() {
         let _ = env_logger::try_init();

src/stream.rs

@@ -28,13 +28,16 @@ impl PacketStream {
         let live_capture = handle.is_live_capture();
 
         if live_capture {
-            let h = handle
+            handle
                 .set_snaplen(config.snaplen())?
                 .set_promiscuous()?
-                .set_buffer_size(config.buffer_size())?
-                .activate()?;
+                .set_buffer_size(config.buffer_size())?;
+            if let Some(datalink) = config.datalink() {
+                handle.set_datalink(*datalink)?;
+            }
+            handle.activate()?;
             if !config.blocking() {
-                h.set_non_block()?;
+                handle.set_non_block()?;
             }
 
             if let Some(bpf) = config.bpf() {