Replace AsSliceU8 trait with zerocopy::AsBytes.

Changed VirtioNetHdr to derive from AsBytes instead of AsSliceU8 and
changed related functions as necessary.

Fixes hermit-os#692.

Author: Joanne Chen

Cargo.lock

@@ -56,16 +56,8 @@ acpi = []
 smp = ["include-transformed"]
 fsgsbase = []
 trace = []
-tcp = [
-    "async-task",
-    "futures-lite",
-    "smoltcp",
-]
-dhcpv4 = [
-    "tcp",
-    "smoltcp/proto-dhcpv4",
-    "smoltcp/socket-dhcpv4",
-]
+tcp = ["async-task", "futures-lite", "smoltcp"]
+dhcpv4 = ["tcp", "smoltcp/proto-dhcpv4", "smoltcp/socket-dhcpv4"]
 
 [dependencies]
 ahash = { version = "0.8", default-features = false }
@@ -90,6 +82,7 @@ lock_api = "0.4"
 num = { version = "0.4", default-features = false }
 num-traits = { version = "0.2", default-features = false }
 num-derive = "0.3"
+zerocopy = "0.6.1"
 
 [dependencies.smoltcp]
 version = "0.9"

Cargo.toml

@@ -10,6 +10,7 @@ use core::cell::RefCell;
 use core::cmp::Ordering;
 use core::mem;
 use core::result::Result;
+use zerocopy::AsBytes;
 
 use self::constants::{FeatureSet, Features, NetHdrGSO, Status, MAX_NUM_VQ};
 use self::error::VirtioNetError;
@@ -25,7 +26,7 @@ use crate::drivers::virtio::transport::mmio::{ComCfg, IsrStatus, NotifCfg};
 #[cfg(feature = "pci")]
 use crate::drivers::virtio::transport::pci::{ComCfg, IsrStatus, NotifCfg};
 use crate::drivers::virtio::virtqueue::{
-	AsSliceU8, BuffSpec, BufferToken, Bytes, Transfer, Virtq, VqIndex, VqSize, VqType,
+	BuffSpec, BufferToken, Bytes, Transfer, Virtq, VqIndex, VqSize, VqType,
 };
 
 pub const ETH_HDR: usize = 14usize;
@@ -41,6 +42,7 @@ pub struct NetDevCfg {
 	pub features: FeatureSet,
 }
 
+#[derive(AsBytes)]
 #[derive(Debug)]
 #[repr(C)]
 pub struct VirtioNetHdr {
@@ -58,9 +60,6 @@ pub struct VirtioNetHdr {
 	num_buffers: u16,
 }
 
-// Using the default implementation of the trait for VirtioNetHdr
-impl AsSliceU8 for VirtioNetHdr {}
-
 impl VirtioNetHdr {
 	pub fn get_tx_hdr() -> VirtioNetHdr {
 		VirtioNetHdr {

src/drivers/net/virtio_net.rs

@@ -19,6 +19,7 @@ use alloc::rc::Rc;
 use alloc::vec::Vec;
 use core::cell::RefCell;
 use core::ops::{BitAnd, Deref, DerefMut};
+use zerocopy::AsBytes;
 
 use align_address::Align;
 
@@ -1683,15 +1684,15 @@ impl BufferToken {
 	///   * Will result in 4 bytes written to the second buffer descriptor of the recv buffer. Nothing is written into the second buffer descriptor.
 	/// * Third Write: `write_seq(Some(10 bytes, Some(4 bytes))`:
 	///   * Will result in 10 bytes written to the second buffer descriptor of the send buffer and 4 bytes written to the third buffer descriptor of the recv buffer.
-	pub fn write_seq<K: AsSliceU8, H: AsSliceU8 + ?Sized>(
+	pub fn write_seq<K: AsBytes, H: AsBytes + ?Sized>(
 		mut self,
 		send_seq: Option<&K>,
 		recv_seq: Option<&H>,
 	) -> Result<Self, VirtqError> {
 		if let Some(data) = send_seq {
 			match self.send_buff.as_mut() {
 				Some(buff) => {
-					match buff.next_write(data.as_slice_u8()) {
+					match buff.next_write(data.as_bytes()) {
 						Ok(_) => (), // Do nothing, write fitted inside descriptor and not to many writes to buffer happened
 						Err(_) => {
 							// Need no match here, as result is the same, but for the future one could
@@ -1707,7 +1708,7 @@ impl BufferToken {
 		if let Some(data) = recv_seq {
 			match self.recv_buff.as_mut() {
 				Some(buff) => {
-					match buff.next_write(data.as_slice_u8()) {
+					match buff.next_write(data.as_bytes()) {
 						Ok(_) => (), // Do nothing, write fitted inside descriptor and not to many writes to buffer happened
 						Err(_) => {
 							// Need no match here, as result is the same, but for the future one could

src/drivers/virtio/virtqueue/mod.rs

@@ -36,6 +36,8 @@ extern crate log;
 extern crate std;
 #[macro_use]
 extern crate num_derive;
+#[macro_use]
+extern crate zerocopy;
 
 use alloc::alloc::Layout;
 use core::alloc::GlobalAlloc;