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aya: tc: clean up netlink code a bit

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pull/32/head
Alessandro Decina 3 years ago
parent b4b019e447
commit 9185f32f6f
1 changed files with 42 additions and 79 deletions
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121
aya/src/sys/netlink.rs
Unescape Escape View File

@ -31,30 +31,22 @@ pub(crate) unsafe fn netlink_set_xdp_fd(
) -> Result<(), io::Error> {
let sock = NetlinkSocket::open()?;
let seq = 1;
// Safety: Request is POD so this is safe
let mut req = mem::zeroed::<Request>();
let nlmsg_len = mem::size_of::<nlmsghdr>() + mem::size_of::<ifinfomsg>();
req.header = nlmsghdr {
nlmsg_len: (mem::size_of::<nlmsghdr>() + mem::size_of::<ifinfomsg>()) as u32,
nlmsg_len: nlmsg_len as u32,
nlmsg_flags: (NLM_F_REQUEST | NLM_F_ACK) as u16,
nlmsg_type: RTM_SETLINK,
nlmsg_pid: 0,
nlmsg_seq: seq,
nlmsg_seq: 1,
};
req.if_info.ifi_family = AF_UNSPEC as u8;
req.if_info.ifi_index = if_index;
let attrs_buf = {
let attrs_addr = align_to(
&req as *const _ as usize + req.header.nlmsg_len as usize,
NLMSG_ALIGNTO as usize,
);
let attrs_end = &req as *const _ as usize + mem::size_of::<Request>();
slice::from_raw_parts_mut(attrs_addr as *mut u8, attrs_end - attrs_addr)
};
// write the attrs
let attrs_buf = request_attributes(&mut req, nlmsg_len);
let mut attrs = NestedAttrs::new(attrs_buf, IFLA_XDP);
attrs.write_attr(IFLA_XDP_FD as u16, fd)?;
@ -69,15 +61,7 @@ pub(crate) unsafe fn netlink_set_xdp_fd(
let nla_len = attrs.finish()?;
req.header.nlmsg_len += align_to(nla_len, NLA_ALIGNTO as usize) as u32;
if send(
sock.sock,
&req as *const _ as *const _,
req.header.nlmsg_len as usize,
0,
) < 0
{
return Err(io::Error::last_os_error());
}
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
sock.recv()?;
@ -87,16 +71,15 @@ pub(crate) unsafe fn netlink_set_xdp_fd(
pub(crate) unsafe fn netlink_qdisc_add_clsact(if_index: i32) -> Result<(), io::Error> {
let sock = NetlinkSocket::open()?;
let seq = 1;
let mut req = mem::zeroed::<QdiscRequest>();
let mut req = mem::zeroed::<TcRequest>();
// prepare the TC rquest
let nlmsg_len = mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>();
req.header = nlmsghdr {
nlmsg_len: (mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>()) as u32,
nlmsg_len: nlmsg_len as u32,
nlmsg_flags: (NLM_F_REQUEST | NLM_F_ACK | NLM_F_EXCL | NLM_F_CREATE) as u16,
nlmsg_type: RTM_NEWQDISC,
nlmsg_pid: 0,
nlmsg_seq: seq,
nlmsg_seq: 1,
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
req.tc_info.tcm_ifindex = if_index;
@ -105,26 +88,11 @@ pub(crate) unsafe fn netlink_qdisc_add_clsact(if_index: i32) -> Result<(), io::E
req.tc_info.tcm_info = 0;
// add the TCA_KIND attribute
let attrs_buf = {
let attrs_addr = align_to(
&req as *const _ as usize + req.header.nlmsg_len as usize,
NLMSG_ALIGNTO as usize,
);
let attrs_end = &req as *const _ as usize + mem::size_of::<QdiscRequest>();
slice::from_raw_parts_mut(attrs_addr as *mut u8, attrs_end - attrs_addr)
};
let attrs_buf = request_attributes(&mut req, nlmsg_len);
let attr_len = write_attr_bytes(attrs_buf, 0, TCA_KIND as u16, b"clsact\0")?;
req.header.nlmsg_len += align_to(attr_len as usize, NLA_ALIGNTO as usize) as u32;
if send(
sock.sock,
&req as *const _ as *const _,
req.header.nlmsg_len as usize,
0,
) < 0
{
return Err(io::Error::last_os_error());
}
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
sock.recv()?;
Ok(())
@ -137,32 +105,24 @@ pub(crate) unsafe fn netlink_qdisc_attach(
prog_name: &CStr,
) -> Result<u32, io::Error> {
let sock = NetlinkSocket::open()?;
let seq = 1;
let priority = 0;
let mut req = mem::zeroed::<QdiscRequest>();
let mut req = mem::zeroed::<TcRequest>();
let nlmsg_len = mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>();
req.header = nlmsghdr {
nlmsg_len: (mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>()) as u32,
nlmsg_len: nlmsg_len as u32,
nlmsg_flags: (NLM_F_REQUEST | NLM_F_ACK | NLM_F_EXCL | NLM_F_CREATE | NLM_F_ECHO) as u16,
nlmsg_type: RTM_NEWTFILTER,
nlmsg_pid: 0,
nlmsg_seq: seq,
nlmsg_seq: 1,
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
req.tc_info.tcm_handle = 0; // auto-assigned, if not provided
req.tc_info.tcm_ifindex = if_index;
req.tc_info.tcm_parent = attach_type.parent();
req.tc_info.tcm_info = tc_handler_make(priority << 16, htons(ETH_P_ALL as u16) as u32);
let attrs_buf = {
let attrs_addr = align_to(
&req as *const _ as usize + req.header.nlmsg_len as usize,
NLMSG_ALIGNTO as usize,
);
let attrs_end = &req as *const _ as usize + mem::size_of::<QdiscRequest>();
slice::from_raw_parts_mut(attrs_addr as *mut u8, attrs_end - attrs_addr)
};
let attrs_buf = request_attributes(&mut req, nlmsg_len);
// add TCA_KIND
let kind_len = write_attr_bytes(attrs_buf, 0, TCA_KIND as u16, b"bpf\0")?;
@ -176,16 +136,7 @@ pub(crate) unsafe fn netlink_qdisc_attach(
let options_len = options.finish()?;
req.header.nlmsg_len += align_to(kind_len + options_len as usize, NLA_ALIGNTO as usize) as u32;
if send(
sock.sock,
&req as *const _ as *const _,
req.header.nlmsg_len as usize,
0,
) < 0
{
return Err(io::Error::last_os_error());
}
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
// find the RTM_NEWTFILTER reply and read the tcm_info field which we'll
// need to detach
@ -218,15 +169,14 @@ pub(crate) unsafe fn netlink_qdisc_detach(
priority: u32,
) -> Result<(), io::Error> {
let sock = NetlinkSocket::open()?;
let seq = 1;
let mut req = mem::zeroed::<QdiscRequest>();
let mut req = mem::zeroed::<TcRequest>();
req.header = nlmsghdr {
nlmsg_len: (mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>()) as u32,
nlmsg_flags: (NLM_F_REQUEST | NLM_F_ACK) as u16,
nlmsg_type: RTM_DELTFILTER,
nlmsg_pid: 0,
nlmsg_seq: seq,
nlmsg_seq: 1,
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
@ -235,15 +185,7 @@ pub(crate) unsafe fn netlink_qdisc_detach(
req.tc_info.tcm_parent = attach_type.parent();
req.tc_info.tcm_ifindex = if_index;
if send(
sock.sock,
&req as *const _ as *const _,
req.header.nlmsg_len as usize,
0,
) < 0
{
return Err(io::Error::last_os_error());
}
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
sock.recv()?;
@ -258,7 +200,7 @@ struct Request {
}
#[repr(C)]
struct QdiscRequest {
struct TcRequest {
header: nlmsghdr,
tc_info: tcmsg,
attrs: [u8; 64],
@ -305,6 +247,13 @@ impl NetlinkSocket {
})
}
fn send(&self, msg: &[u8]) -> Result<(), io::Error> {
if unsafe { send(self.sock, msg.as_ptr() as *const _, msg.len(), 0) } < 0 {
return Err(io::Error::last_os_error());
}
Ok(())
}
fn recv(&self) -> Result<Vec<NetlinkMessage>, io::Error> {
let mut buf = [0u8; 4096];
let mut messages = Vec::new();
@ -487,6 +436,20 @@ fn write_bytes(buf: &mut [u8], offset: usize, value: &[u8]) -> Result<usize, io:
Ok(value.len())
}
unsafe fn request_attributes<T>(req: &mut T, msg_len: usize) -> &mut [u8] {
let attrs_addr = align_to(
req as *const _ as usize + msg_len as usize,
NLMSG_ALIGNTO as usize,
);
let attrs_end = req as *const _ as usize + mem::size_of::<T>();
slice::from_raw_parts_mut(attrs_addr as *mut u8, attrs_end - attrs_addr)
}
fn bytes_of<T>(val: &T) -> &[u8] {
let size = mem::size_of::<T>();
unsafe { slice::from_raw_parts(slice::from_ref(val).as_ptr().cast(), size) }
}
#[cfg(test)]
mod tests {
use super::*;

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