feat(net): Add Allocate trait

We need to abstract the creation of buffers. Add trait Allocate
to PacketBufferMut.

Signed-off-by: Fredi Raspall <[email protected]>

Author: Fredi-raspall

dpdk/src/mem.rs

@@ -26,7 +26,7 @@ use dpdk_sys::{
     rte_pktmbuf_tailroom, rte_pktmbuf_trim,
 };
 // unfortunately, we need the standard library to swap allocators
-use net::buffer::{Append, Headroom, Prepend, Tailroom, TrimFromEnd, TrimFromStart};
+use net::buffer::{Append, Create, Headroom, Prepend, Tailroom, TrimFromEnd, TrimFromStart};
 use std::alloc::System;
 use std::ffi::CString;
 
@@ -422,7 +422,18 @@ impl AsMut<[u8]> for Mbuf {
         self.raw_data_mut()
     }
 }
-
+impl Create for Mbuf {
+    type PoolType = Pool;
+    fn create(pool: &mut Self::PoolType) -> Result<Self, ()> {
+        unsafe {
+            let raw = dpdk_sys::rte_pktmbuf_alloc(pool.inner().as_mut_ptr());
+            Ok(Self {
+                raw: NonNull::new(raw).ok_or_else(|| error!("Mbuf allocation failure"))?,
+                marker: PhantomData,
+            })
+        }
+    }
+}
 impl Headroom for Mbuf {
     fn headroom(&self) -> u16 {
         unsafe { rte_pktmbuf_headroom(self.raw.as_ptr()) }

net/src/buffer/mod.rs

@@ -19,7 +19,15 @@ impl<T> PacketBuffer for T where T: AsRef<[u8]> + Headroom + Debug + 'static {}
 
 /// Super trait representing the abstract operations which may be performed on mutable a packet buffer.
 pub trait PacketBufferMut:
-    PacketBuffer + AsMut<[u8]> + Prepend + Send + TrimFromStart + TrimFromEnd + Headroom + Tailroom
+    PacketBuffer
+    + AsMut<[u8]>
+    + Prepend
+    + Send
+    + TrimFromStart
+    + TrimFromEnd
+    + Headroom
+    + Tailroom
+    + Create
 {
 }
 impl<T> PacketBufferMut for T where
@@ -31,9 +39,20 @@ impl<T> PacketBufferMut for T where
         + TrimFromEnd
         + Headroom
         + Tailroom
+        + Create
 {
 }
 
+/// Trait representing the ability to create a packet buffer
+pub trait Create {
+    /// Type of auxiliary object to allocate buffers from
+    type PoolType;
+    /// Allocate a packet buffer
+    fn create(pool: &mut Self::PoolType) -> Result<Self, ()>
+    where
+        Self: Sized;
+}
+
 /// Trait representing the ability to get the unused headroom in a packet buffer.
 pub trait Headroom {
     /// Get the (unused) headroom in a packet buffer.

net/src/buffer/test_buffer.rs

@@ -7,8 +7,8 @@
 pub use contract::*;
 
 use crate::buffer::{
-    Append, Headroom, MemoryBufferNotLongEnough, NotEnoughHeadRoom, NotEnoughTailRoom, Prepend,
-    Tailroom, TrimFromEnd, TrimFromStart,
+    Append, Create, Headroom, MemoryBufferNotLongEnough, NotEnoughHeadRoom, NotEnoughTailRoom,
+    Prepend, Tailroom, TrimFromEnd, TrimFromStart,
 };
 use tracing::trace;
 
@@ -103,6 +103,13 @@ impl AsMut<[u8]> for TestBuffer {
     }
 }
 
+impl Create for TestBuffer {
+    type PoolType = ();
+    fn create(_: &mut Self::PoolType) -> Result<Self, ()> {
+        Ok(Self::new())
+    }
+}
+
 impl Headroom for TestBuffer {
     fn headroom(&self) -> u16 {
         self.headroom