Enable user to send to iface directly via packet socket

kernel/src/drivers/mod.rs

@@ -66,6 +66,11 @@ pub trait Driver: Send + Sync {
         unimplemented!("not a net driver")
     }
 
+    // send an ethernet frame, only use it when necessary
+    fn send(&self, data: &[u8]) -> Option<usize> {
+        unimplemented!("not a net driver")
+    }
+
     // block related drivers should implement these
     fn read_block(&self, block_id: usize, buf: &mut [u8]) -> bool {
         unimplemented!("not a block driver")

kernel/src/drivers/net/e1000.rs

@@ -149,6 +149,23 @@ impl Driver for E1000Interface {
             }
         }
     }
+
+    // send an ethernet frame, only use it when necessary
+    fn send(&self, data: &[u8]) -> Option<usize> {
+        use smoltcp::phy::TxToken;
+        let token = E1000TxToken(self.driver.clone());
+        if token
+            .consume(Instant::from_millis(0), data.len(), |buffer| {
+                buffer.copy_from_slice(&data);
+                Ok(())
+            })
+            .is_ok()
+        {
+            Some(data.len())
+        } else {
+            None
+        }
+    }
 }
 
 #[repr(C)]

kernel/src/net/structs.rs

@@ -8,7 +8,17 @@ use smoltcp::socket::*;
 use smoltcp::wire::*;
 
 #[derive(Clone, Debug)]
-pub struct LinkLevelEndpoint {}
+pub struct LinkLevelEndpoint {
+    interface_index: usize,
+}
+
+impl LinkLevelEndpoint {
+    pub fn new(ifindex: usize) -> Self {
+        LinkLevelEndpoint {
+            interface_index: ifindex,
+        }
+    }
+}
 
 #[derive(Clone, Debug)]
 pub enum Endpoint {
@@ -633,8 +643,12 @@ impl Socket for PacketSocketState {
     }
 
     fn write(&self, data: &[u8], sendto_endpoint: Option<Endpoint>) -> SysResult {
-        if let Some(endpoint) = sendto_endpoint {
+        if let Some(Endpoint::LinkLevel(endpoint)) = sendto_endpoint {
-            unimplemented!()
+            let ifaces = NET_DRIVERS.read();
+            match ifaces[endpoint.interface_index].send(data) {
+                Some(len) => Ok(len),
+                None => Err(SysError::ENOBUFS),
+            }
         } else {
             Err(SysError::ENOTCONN)
         }

kernel/src/syscall/net.rs

@@ -4,7 +4,8 @@ use super::*;
 use crate::drivers::SOCKET_ACTIVITY;
 use crate::fs::FileLike;
 use crate::net::{
-    Endpoint, PacketSocketState, RawSocketState, Socket, TcpSocketState, UdpSocketState, SOCKETS,
+    Endpoint, LinkLevelEndpoint, PacketSocketState, RawSocketState, Socket, TcpSocketState,
+    UdpSocketState, SOCKETS,
 };
 use crate::sync::{MutexGuard, SpinNoIrq, SpinNoIrqLock as Mutex};
 use alloc::boxed::Box;
@@ -288,14 +289,15 @@ pub struct SockAddrUn {
     sun_path: [u8; 108],
 }
 
-#[repr(C)]
+// beware of alignment issue
+#[repr(C, packed)]
 pub struct SockAddrLl {
     sll_protocol: u16,
     sll_ifindex: u32,
     sll_hatype: u16,
     sll_pkttype: u8,
     sll_halen: u8,
-    sll_addr: u8,
+    sll_addr: [u8; 8],
 }
 
 #[repr(C)]
@@ -361,7 +363,9 @@ fn sockaddr_to_endpoint(
                 if len < size_of::<u16>() + size_of::<SockAddrLl>() {
                     return Err(SysError::EINVAL);
                 }
-                unimplemented!()
+                Ok(Endpoint::LinkLevel(LinkLevelEndpoint::new(
+                    (*addr).payload.addr_ll.sll_ifindex as usize,
+                )))
             }
             _ => Err(SysError::EINVAL),
         }