Merge pull request #1161 from cagatay-y/smoltcp

virtio_net: use smoltcp methods instead of hardcoding field offsets
hermit-os · Apr 30, 2024 · e064a6a · e064a6a
2 parents 643d612 + 9fca0a1
commit e064a6a
Showing 1 changed file with 27 additions and 29 deletions.
diff --git a/src/drivers/net/virtio_net.rs b/src/drivers/net/virtio_net.rs
@@ -12,7 +12,7 @@ use core::mem;
 use align_address::Align;
 use pci_types::InterruptLine;
 use smoltcp::phy::{Checksum, ChecksumCapabilities};
-use smoltcp::wire::{ETHERNET_HEADER_LEN, IPV4_HEADER_LEN, IPV6_HEADER_LEN};
+use smoltcp::wire::{EthernetFrame, Ipv4Packet, Ipv6Packet, ETHERNET_HEADER_LEN};
 use zerocopy::AsBytes;
 
 use self::constants::{FeatureSet, Features, NetHdrFlag, NetHdrGSO, Status, MAX_NUM_VQ};
@@ -523,35 +523,33 @@ impl NetworkDriver for VirtioNetDriver {
 			// If a checksum isn't necessary, we have inform the host within the header
 			// see Virtio specification 5.1.6.2
 			if !self.checksums.tcp.tx() || !self.checksums.udp.tx() {
-				let type_ = unsafe { u16::from_be(*(buff_ptr.offset(12) as *const u16)) };
-
-				match type_ {
-					0x0800 /* IPv4 */ => {
-						let protocol = unsafe { *(buff_ptr.offset((ETHERNET_HEADER_LEN+9).try_into().unwrap()) as *const u8) };
-						if protocol == 6 /* TCP */ {
-							header.flags = NetHdrFlag::VIRTIO_NET_HDR_F_NEEDS_CSUM;
-							header.csum_start = (ETHERNET_HEADER_LEN+IPV4_HEADER_LEN).try_into().unwrap();
-							header.csum_offset = 16;
-						} else if protocol == 17 /* UDP */ {
-							header.flags = NetHdrFlag::VIRTIO_NET_HDR_F_NEEDS_CSUM;
-							header.csum_start = (ETHERNET_HEADER_LEN+IPV4_HEADER_LEN).try_into().unwrap();
-							header.csum_offset = 6;
-						}
-					},
-					0x86DD /* IPv6 */ => {
-						let protocol = unsafe { *(buff_ptr.offset((ETHERNET_HEADER_LEN+9).try_into().unwrap()) as *const u8) };
-						if protocol == 6 /* TCP */ {
-							header.flags = NetHdrFlag::VIRTIO_NET_HDR_F_NEEDS_CSUM;
-							header.csum_start = (ETHERNET_HEADER_LEN+IPV6_HEADER_LEN).try_into().unwrap();
-							header.csum_offset = 16;
-						} else if protocol == 17 /* UDP */ {
-							header.flags = NetHdrFlag::VIRTIO_NET_HDR_F_NEEDS_CSUM;
-							header.csum_start = (ETHERNET_HEADER_LEN+IPV6_HEADER_LEN).try_into().unwrap();
-							header.csum_offset = 6;
-						}
-					},
-					_ => {},
+				header.flags = NetHdrFlag::VIRTIO_NET_HDR_F_NEEDS_CSUM;
+				let ethernet_frame: smoltcp::wire::EthernetFrame<&[u8]> =
+					EthernetFrame::new_unchecked(buf_slice);
+				let packet_header_len: u16;
+				let protocol;
+				match ethernet_frame.ethertype() {
+					smoltcp::wire::EthernetProtocol::Ipv4 => {
+						let packet = Ipv4Packet::new_unchecked(ethernet_frame.payload());
+						packet_header_len = packet.header_len().into();
+						protocol = Some(packet.next_header());
+					}
+					smoltcp::wire::EthernetProtocol::Ipv6 => {
+						let packet = Ipv6Packet::new_unchecked(ethernet_frame.payload());
+						packet_header_len = packet.header_len().try_into().unwrap();
+						protocol = Some(packet.next_header());
+					}
+					_ => {
+						packet_header_len = 0;
+						protocol = None;
+					}
 				}
+				header.csum_start = u16::try_from(ETHERNET_HEADER_LEN).unwrap() + packet_header_len;
+				header.csum_offset = match protocol {
+					Some(smoltcp::wire::IpProtocol::Tcp) => 16,
+					Some(smoltcp::wire::IpProtocol::Udp) => 6,
+					_ => 0,
+				};
 			}
 
 			buff_tkn