network: recalculate TCP checksums on IPv4 in vbridge

This commit is contained in:
Alex Zenla 2024-02-12 20:57:17 +00:00
parent d595f1639a
commit 494e7f6851
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GPG Key ID: 067B238899B51269

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@ -1,6 +1,6 @@
use anyhow::{anyhow, Result};
use bytes::BytesMut;
use etherparse::Ethernet2Header;
use etherparse::{EtherType, Ethernet2Header, IpNumber, Ipv4Header, TcpHeader};
use log::{debug, trace, warn};
use smoltcp::wire::EthernetAddress;
use std::{
@ -121,26 +121,45 @@ impl VirtualBridge {
match selection {
VirtualBridgeSelect::PacketReceived(Some(packet)) => {
let header = match Ethernet2Header::from_slice(&packet) {
Ok((header, _)) => header,
let mut packet: Vec<u8> = packet.into();
let (header, payload) = match Ethernet2Header::from_slice(&packet) {
Ok(data) => data,
Err(error) => {
debug!("virtual bridge failed to parse ethernet header: {}", error);
continue;
}
};
if header.ether_type == EtherType::IPV4 {
let (ipv4, payload) = Ipv4Header::from_slice(payload)?;
// recalculate TCP checksums when routing packets.
// the xen network backend / frontend drivers for linux
// are very stupid and do not calculate these properly
// despite all best attempts as making it do so.
if ipv4.protocol == IpNumber::TCP {
let (mut tcp, payload) = TcpHeader::from_slice(payload)?;
tcp.checksum = tcp.calc_checksum_ipv4(&ipv4, payload)?;
let tcp_header_offset = Ethernet2Header::LEN + ipv4.header_len();
let tcp_header_bytes = tcp.to_bytes();
for (i, b) in tcp_header_bytes.iter().enumerate() {
packet[tcp_header_offset + i] = *b;
}
}
}
let destination = &header.destination;
if destination == BROADCAST_MAC_ADDR {
trace!(
"broadcasting bridged packet from {}",
EthernetAddress(header.source)
);
broadcast_rx_sender.send(packet)?;
broadcast_rx_sender.send(packet.as_slice().into())?;
continue;
}
match members.lock().await.get(destination) {
Some(member) => {
member.bridge_rx_sender.try_send(packet)?;
member.bridge_rx_sender.try_send(packet.as_slice().into())?;
trace!(
"sending bridged packet from {} to {}",
EthernetAddress(header.source),