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use crate::unix::{aligned_buffer::U32AlignedBuffer, Fd};
use crate::IfEvent;
use async_io::Async;
use ipnet::{IpNet, Ipv4Net, Ipv6Net};
use netlink::NetlinkIterator;
use std::{
collections::VecDeque,
io::{Error, Result},
mem::MaybeUninit,
net::IpAddr,
os::unix::prelude::*,
};
mod netlink;
mod rtnetlink;
#[allow(non_camel_case_types)]
#[derive(Debug)]
#[repr(C)]
struct sockaddr_nl {
nl_family: libc::sa_family_t,
nl_pad: libc::c_ushort,
nl_pid: u32,
nl_groups: u32,
}
#[derive(Debug)]
pub struct NetlinkSocket {
fd: Async<Fd>,
address: sockaddr_nl,
seqnum: u32,
pid: u32,
}
const RTMGRP_IPV4_IFADDR: u32 = 0x10;
const RTMGRP_IPV6_IFADDR: u32 = 0x100;
const RTM_NEWADDR: i32 = libc::RTM_NEWADDR as _;
const RTM_DELADDR: i32 = libc::RTM_DELADDR as _;
impl NetlinkSocket {
pub fn new() -> Result<Self> {
unsafe {
let flags = libc::SOCK_RAW | libc::SOCK_CLOEXEC;
let fd = Fd::new(errno!(libc::socket(
libc::AF_NETLINK,
flags,
libc::NETLINK_ROUTE
))?)?;
let mut address: sockaddr_nl = std::mem::zeroed();
address.nl_family = libc::AF_NETLINK as _;
address.nl_groups = RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
let ptr = &mut address as *mut _;
let mut size = size_of!(sockaddr_nl) as u32;
errno!(libc::bind(fd.as_raw_fd(), ptr as *mut _, size))?;
errno!(libc::getsockname(fd.as_raw_fd(), ptr as *mut _, &mut size))?;
let pid = address.nl_pid;
address.nl_pid = 0;
address.nl_groups = 0;
Ok(Self {
fd,
address,
seqnum: 0,
pid,
})
}
}
pub async fn send_getaddr(&mut self) -> Result<()> {
#[repr(C)]
struct Nlmsg {
hdr: libc::nlmsghdr,
msg: rtnetlink::ifaddrmsg,
};
if self.seqnum == u32::max_value() {
self.seqnum = 1;
} else {
self.seqnum += 1;
}
let msg = Nlmsg {
hdr: libc::nlmsghdr {
nlmsg_len: size_of!(Nlmsg) as _,
nlmsg_type: libc::RTM_GETADDR,
nlmsg_flags: (libc::NLM_F_REQUEST | libc::NLM_F_MULTI | libc::NLM_F_DUMP) as _,
nlmsg_seq: self.seqnum,
nlmsg_pid: self.address.nl_pid,
},
msg: rtnetlink::ifaddrmsg {
ifa_family: libc::AF_UNSPEC as _,
ifa_prefixlen: 0,
ifa_flags: 0,
ifa_scope: 0,
ifa_index: 0,
},
};
self.fd
.write_with(|fd| unsafe {
let msg: *const _ = &msg;
let address: *const _ = &self.address;
errno!(libc::sendto(
fd.as_raw_fd(),
msg as *const _,
size_of!(Nlmsg),
libc::MSG_NOSIGNAL,
address as _,
std::mem::size_of_val(&self.address) as _,
))?;
Ok(())
})
.await
}
pub async fn recv_event(&mut self, queue: &mut VecDeque<IfEvent>) -> Result<()> {
let mut buf = [0u64; 512];
let iter = loop {
let res = self
.fd
.read_with(|fd| unsafe {
let mut address = MaybeUninit::<libc::sockaddr_nl>::uninit();
let mut iovec = libc::iovec {
iov_base: buf.as_mut_ptr() as *mut _,
iov_len: buf.len() * size_of!(u64),
};
let mut msghdr: libc::msghdr = std::mem::zeroed();
msghdr.msg_name = address.as_mut_ptr() as _;
msghdr.msg_namelen = size_of!(libc::sockaddr_nl) as _;
msghdr.msg_iov = &mut iovec;
msghdr.msg_iovlen = 1;
msghdr.msg_control = std::ptr::null_mut();
msghdr.msg_controllen = 0;
msghdr.msg_flags = 0;
let flags = libc::MSG_TRUNC | libc::MSG_CMSG_CLOEXEC;
let status = errno!(libc::recvmsg(fd.as_raw_fd(), &mut msghdr, flags))?;
if msghdr.msg_namelen as usize != size_of!(libc::sockaddr_nl)
|| msghdr.msg_flags & (libc::MSG_TRUNC | libc::MSG_CTRUNC) != 0
{
log::error!("rtnetlink message was truncated");
return Ok(None);
}
let address = address.assume_init();
if address.nl_family != libc::AF_NETLINK as u16 {
log::trace!("wrong address family");
return Ok(None);
}
if address.nl_pid != 0 {
log::trace!("message not from kernel");
return Ok(None);
}
let msg =
std::slice::from_raw_parts(iovec.iov_base as *const u8, status as usize);
Ok(Some(msg))
})
.await?;
if let Some(msg) = res {
break NetlinkIterator::new(msg);
}
};
for (hdr, mut body) in iter {
match hdr.nlmsg_type as i32 {
libc::NLMSG_NOOP => {}
libc::NLMSG_DONE => return Ok(()),
RTM_NEWADDR | RTM_DELADDR => {
read_ifaddrmsg(queue, hdr.nlmsg_type as i32, &mut body);
}
other => {
println!("{}", other);
}
}
}
Ok(())
}
}
fn read_ifaddrmsg<'a>(queue: &mut VecDeque<IfEvent>, ty: i32, msg: &mut U32AlignedBuffer<'a>) {
let (hdr, iter) = rtnetlink::read_msg::<rtnetlink::ifaddrmsg>(msg)
.expect("kernel only sends valid messages; qed");
let family = hdr.ifa_family as i32;
if family != libc::AF_INET && family != libc::AF_INET6 {
log::trace!("Skipping unknown address family");
return;
}
let ip = iter
.filter_map(|e| match e {
rtnetlink::RtaMessage::IPAddr(e) => Some(e),
rtnetlink::RtaMessage::Other => None,
})
.next()
.expect(
"RTM_NEWROUTE and RTM_DELROUTE messages always contain a destination \
address, so if you hit this panic, your kernel is broken; qed",
);
let prefix = hdr.ifa_prefixlen;
let ipnet = match ip {
IpAddr::V4(ip) => IpNet::V4(Ipv4Net::new(ip, prefix).expect("kernel sent valid prefix")),
IpAddr::V6(ip) => IpNet::V6(Ipv6Net::new(ip, prefix).expect("kernel sent valid prefix")),
};
match ty {
RTM_NEWADDR => queue.push_back(IfEvent::Up(ipnet)),
RTM_DELADDR => queue.push_back(IfEvent::Down(ipnet)),
_ => {}
}
}
impl AsRawFd for NetlinkSocket {
fn as_raw_fd(&self) -> RawFd {
self.fd.as_raw_fd()
}
}
