Files
route-switcher/src/routing.rs
2026-03-01 08:22:18 +01:00

341 lines
11 KiB
Rust

use anyhow::Result;
use libc::if_nametoindex;
use log::{debug, info};
use netlink_packet_route::route::RouteAddress;
use std::ffi::CString;
use std::net::Ipv4Addr;
const MAIN_TABLE_ID: u8 = 254;
// Route metrics - higher priority = lower number
const FAILOVER_METRIC: u32 = 5;
const PRIMARY_METRIC: u32 = 10;
const SECONDARY_METRIC: u32 = 20;
#[derive(Debug, Clone)]
pub struct RouteInfo {
pub gateway: Ipv4Addr,
pub interface: String,
pub metric: u32,
}
pub struct RouteManager {
routes: Vec<RouteInfo>,
}
impl RouteManager {
pub fn new() -> Self {
RouteManager { routes: Vec::new() }
}
pub fn add_route(&mut self, gateway: Ipv4Addr, interface: String, metric: u32) -> Result<()> {
let route_info = RouteInfo {
gateway,
interface: interface.clone(),
metric,
};
self.add_default_route_internal(&route_info)?;
self.routes.push(route_info);
info!(
"Added route: {} via {} dev {} metric {}",
Ipv4Addr::new(0, 0, 0, 0),
gateway,
interface,
metric
);
Ok(())
}
pub fn remove_route(&mut self, gateway: Ipv4Addr, interface: &str, metric: u32) -> Result<()> {
self.delete_default_route_internal(gateway, interface, metric)?;
self.routes
.retain(|r| !(r.gateway == gateway && r.interface == interface && r.metric == metric));
info!(
"Removed route: {} via {} dev {} metric {}",
Ipv4Addr::new(0, 0, 0, 0),
gateway,
interface,
metric
);
Ok(())
}
pub fn set_primary_route(&mut self, gateway: Ipv4Addr, interface: String) -> Result<()> {
// Remove existing routes for this interface if any
if let Some(pos) = self.routes.iter().position(|r| r.interface == interface) {
let existing_route = self.routes[pos].clone();
self.remove_route(
existing_route.gateway,
&existing_route.interface,
existing_route.metric,
)?;
}
// Add as primary route
self.add_route(gateway, interface, PRIMARY_METRIC)?;
Ok(())
}
pub fn setup_initial_routes(
&mut self,
primary_gateway: Ipv4Addr,
primary_interface: String,
secondary_gateway: Ipv4Addr,
secondary_interface: String,
) -> Result<()> {
// Set primary route with metric 10 (default)
self.set_primary_route(primary_gateway, primary_interface)?;
// Set secondary route with metric 20 (lower priority)
self.add_route(secondary_gateway, secondary_interface, SECONDARY_METRIC)?;
Ok(())
}
pub fn add_failover_route(&mut self, gateway: Ipv4Addr, interface: String) -> Result<()> {
self.add_route(gateway, interface, FAILOVER_METRIC)?;
Ok(())
}
pub fn remove_failover_route(&mut self, gateway: Ipv4Addr, interface: String) -> Result<()> {
self.remove_route(gateway, &interface, FAILOVER_METRIC)?;
Ok(())
}
#[allow(dead_code)]
pub fn get_routes(&self) -> &[RouteInfo] {
&self.routes
}
fn add_default_route_internal(&self, route_info: &RouteInfo) -> Result<()> {
let index = get_interface_index(&route_info.interface)?;
if index == 0 {
return Err(anyhow::anyhow!(
"Interface '{}' not found",
route_info.interface
));
}
use netlink_packet_core::{
NLM_F_ACK, NLM_F_CREATE, NLM_F_REQUEST, NetlinkHeader, NetlinkMessage, NetlinkPayload,
};
use netlink_packet_route::{
AddressFamily, RouteNetlinkMessage,
route::RouteProtocol,
route::RouteScope,
route::{RouteAttribute, RouteHeader, RouteMessage, RouteType},
};
use netlink_sys::{Socket, SocketAddr, protocols::NETLINK_ROUTE};
let mut socket = Socket::new(NETLINK_ROUTE)?;
let _port_number = socket.bind_auto()?.port_number();
socket.connect(&SocketAddr::new(0, 0))?;
let route_msg_hdr = RouteHeader {
address_family: AddressFamily::Inet,
table: MAIN_TABLE_ID,
destination_prefix_length: 0, // Default route
protocol: RouteProtocol::Boot,
scope: RouteScope::Universe,
kind: RouteType::Unicast,
..Default::default()
};
let mut route_msg = RouteMessage::default();
route_msg.header = route_msg_hdr;
route_msg.attributes = vec![
RouteAttribute::Gateway(RouteAddress::Inet(route_info.gateway)),
RouteAttribute::Oif(index),
RouteAttribute::Priority(route_info.metric),
];
let mut nl_hdr = NetlinkHeader::default();
nl_hdr.flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK; // Remove NLM_F_EXCL to allow updates
let mut msg = NetlinkMessage::new(
nl_hdr,
NetlinkPayload::from(RouteNetlinkMessage::NewRoute(route_msg)),
);
msg.finalize();
let mut buf = vec![0; 1024 * 8];
msg.serialize(&mut buf[..msg.buffer_len()]);
// Debug: Log the netlink message being sent
debug!("Netlink message being sent: {:?}", &buf[..msg.buffer_len()]);
debug!(
"Route addition attempt: gateway={}, interface={}, metric={}, interface_index={}",
route_info.gateway, route_info.interface, route_info.metric, index
);
socket.send(&buf, 0)?;
let mut receive_buffer = Vec::with_capacity(256);
let size = socket.recv(&mut receive_buffer, 0)?;
if size == 0 {
return Err(anyhow::anyhow!("No response from netlink"));
}
let bytes = &receive_buffer[..size];
let rx_packet = <NetlinkMessage<RouteNetlinkMessage>>::deserialize(bytes);
match rx_packet {
Ok(rx_packet) => {
if let NetlinkPayload::Error(error_msg) = rx_packet.payload {
if let Some(code) = error_msg.code {
let error_code = code.get();
if error_code == -17 {
// EEXIST - Route already exists, treat as success
info!(
"Route already exists: {} via {} dev {} metric {}",
Ipv4Addr::new(0, 0, 0, 0),
route_info.gateway,
route_info.interface,
route_info.metric
);
} else {
let error_str = match error_code {
-1 => "EPERM - Operation not permitted (need root privileges)",
-2 => "ENOENT - No such file or directory",
-13 => "EACCES - Permission denied",
-22 => "EINVAL - Invalid argument",
_ => "Unknown error",
};
return Err(anyhow::anyhow!(
"Failed to add route: {} (code: {}): {:?}",
error_str,
error_code,
error_msg
));
}
}
debug!("Route added successfully");
}
}
Err(e) => {
return Err(anyhow::anyhow!(
"Failed to deserialize netlink message: {}",
e
));
}
}
Ok(())
}
fn delete_default_route_internal(
&self,
gateway: Ipv4Addr,
interface: &str,
metric: u32,
) -> Result<()> {
let index = get_interface_index(interface)?;
if index == 0 {
return Err(anyhow::anyhow!("Interface '{}' not found", interface));
}
use netlink_packet_core::{
NLM_F_ACK, NLM_F_REQUEST, NetlinkHeader, NetlinkMessage, NetlinkPayload,
};
use netlink_packet_route::{
AddressFamily, RouteNetlinkMessage,
route::RouteProtocol,
route::RouteScope,
route::{RouteAttribute, RouteHeader, RouteMessage, RouteType},
};
use netlink_sys::{Socket, SocketAddr, protocols::NETLINK_ROUTE};
let mut socket = Socket::new(NETLINK_ROUTE)?;
let _port_number = socket.bind_auto()?.port_number();
socket.connect(&SocketAddr::new(0, 0))?;
let route_msg_hdr = RouteHeader {
address_family: AddressFamily::Inet,
table: MAIN_TABLE_ID,
destination_prefix_length: 0, // Default route
protocol: RouteProtocol::Boot,
scope: RouteScope::Universe,
kind: RouteType::Unicast,
..Default::default()
};
let mut route_msg = RouteMessage::default();
route_msg.header = route_msg_hdr;
route_msg.attributes = vec![
RouteAttribute::Gateway(RouteAddress::Inet(gateway)),
RouteAttribute::Oif(index),
RouteAttribute::Priority(metric),
];
let mut nl_hdr = NetlinkHeader::default();
nl_hdr.flags = NLM_F_REQUEST | NLM_F_ACK;
let mut msg = NetlinkMessage::new(
nl_hdr,
NetlinkPayload::from(RouteNetlinkMessage::DelRoute(route_msg)),
);
msg.finalize();
let mut buf = vec![0; 1024 * 8];
msg.serialize(&mut buf[..msg.buffer_len()]);
// Debug: Log the netlink message being sent
debug!(
"Netlink delete message being sent: {:?}",
&buf[..msg.buffer_len()]
);
debug!(
"Route deletion attempt: gateway={}, interface={}, metric={}, interface_index={}",
gateway, interface, metric, index
);
socket.send(&buf, 0)?;
let mut receive_buffer = Vec::with_capacity(256);
let size = socket.recv(&mut receive_buffer, 0)?;
if size == 0 {
return Err(anyhow::anyhow!("No response from netlink"));
}
let bytes = &receive_buffer[..size];
let rx_packet = <NetlinkMessage<RouteNetlinkMessage>>::deserialize(bytes);
match rx_packet {
Ok(rx_packet) => {
if let NetlinkPayload::Error(error_msg) = rx_packet.payload {
if error_msg.code.is_some() {
return Err(anyhow::anyhow!("Failed to delete route: {:?}", error_msg));
}
debug!("Route deleted successfully");
}
}
Err(e) => {
return Err(anyhow::anyhow!(
"Failed to deserialize netlink message: {}",
e
));
}
}
Ok(())
}
}
fn get_interface_index(iface_name: &str) -> Result<u32> {
let c_name = CString::new(iface_name)?;
let index = unsafe { if_nametoindex(c_name.as_ptr()) };
if index == 0 {
Err(anyhow::anyhow!("Interface '{}' not found", iface_name))
} else {
Ok(index)
}
}