cgroups_rs/
net_prio.rs

1// Copyright (c) 2018 Levente Kurusa
2//
3// SPDX-License-Identifier: Apache-2.0 or MIT
4//
5
6//! This module contains the implementation of the `net_prio` cgroup subsystem.
7//!
8//! See the Kernel's documentation for more information about this subsystem, found at:
9//!  [Documentation/cgroup-v1/net_prio.txt](https://www.kernel.org/doc/Documentation/cgroup-v1/net_prio.txt)
10use std::collections::HashMap;
11use std::io::{BufRead, BufReader, Write};
12use std::path::PathBuf;
13
14use crate::error::ErrorKind::*;
15use crate::error::*;
16
17use crate::read_u64_from;
18use crate::{
19    ControllIdentifier, ControllerInternal, Controllers, NetworkResources, Resources, Subsystem,
20};
21
22/// A controller that allows controlling the `net_prio` subsystem of a Cgroup.
23///
24/// In essence, using `net_prio` one can set the priority of the packets emitted from the control
25/// group's tasks. This can then be used to have QoS restrictions on certain control groups and
26/// thus, prioritizing certain tasks.
27#[derive(Debug, Clone)]
28pub struct NetPrioController {
29    base: PathBuf,
30    path: PathBuf,
31}
32
33impl ControllerInternal for NetPrioController {
34    fn control_type(&self) -> Controllers {
35        Controllers::NetPrio
36    }
37    fn get_path(&self) -> &PathBuf {
38        &self.path
39    }
40    fn get_path_mut(&mut self) -> &mut PathBuf {
41        &mut self.path
42    }
43    fn get_base(&self) -> &PathBuf {
44        &self.base
45    }
46
47    fn apply(&self, res: &Resources) -> Result<()> {
48        // get the resources that apply to this controller
49        let res: &NetworkResources = &res.network;
50
51        for i in &res.priorities {
52            let _ = self.set_if_prio(&i.name, i.priority);
53        }
54
55        Ok(())
56    }
57}
58
59impl ControllIdentifier for NetPrioController {
60    fn controller_type() -> Controllers {
61        Controllers::NetPrio
62    }
63}
64
65impl<'a> From<&'a Subsystem> for &'a NetPrioController {
66    fn from(sub: &'a Subsystem) -> &'a NetPrioController {
67        unsafe {
68            match sub {
69                Subsystem::NetPrio(c) => c,
70                _ => {
71                    assert_eq!(1, 0);
72                    let v = std::mem::MaybeUninit::uninit();
73                    v.assume_init()
74                }
75            }
76        }
77    }
78}
79
80impl NetPrioController {
81    /// Constructs a new `NetPrioController` with `root` serving as the root of the control group.
82    pub fn new(root: PathBuf) -> Self {
83        Self {
84            base: root.clone(),
85            path: root,
86        }
87    }
88
89    /// Retrieves the current priority of the emitted packets.
90    pub fn prio_idx(&self) -> u64 {
91        self.open_path("net_prio.prioidx", false)
92            .and_then(read_u64_from)
93            .unwrap_or(0)
94    }
95
96    /// A map of priorities for each network interface.
97    #[allow(clippy::iter_nth_zero, clippy::unnecessary_unwrap)]
98    pub fn ifpriomap(&self) -> Result<HashMap<String, u64>> {
99        self.open_path("net_prio.ifpriomap", false)
100            .and_then(|file| {
101                let bf = BufReader::new(file);
102                bf.lines().fold(Ok(HashMap::new()), |acc, line| {
103                    if acc.is_err() {
104                        acc
105                    } else {
106                        let mut acc = acc.unwrap();
107                        let l = line.unwrap();
108                        let mut sp = l.split_whitespace();
109
110                        let ifname = sp.nth(0);
111                        let ifprio = sp.nth(1);
112                        if ifname.is_none() || ifprio.is_none() {
113                            Err(Error::new(ParseError))
114                        } else {
115                            let ifname = ifname.unwrap();
116                            let ifprio = ifprio.unwrap().trim().parse();
117                            match ifprio {
118                                Err(e) => Err(Error::with_cause(ParseError, e)),
119                                Ok(_) => {
120                                    acc.insert(ifname.to_string(), ifprio.unwrap());
121                                    Ok(acc)
122                                }
123                            }
124                        }
125                    }
126                })
127            })
128    }
129
130    /// Set the priority of the network traffic on `eif` to be `prio`.
131    pub fn set_if_prio(&self, eif: &str, prio: u64) -> Result<()> {
132        self.open_path("net_prio.ifpriomap", true)
133            .and_then(|mut file| {
134                file.write_all(format!("{} {}", eif, prio).as_ref())
135                    .map_err(|e| {
136                        Error::with_cause(
137                            WriteFailed(
138                                "net_prio.ifpriomap".to_string(),
139                                format!("{} {}", eif, prio),
140                            ),
141                            e,
142                        )
143                    })
144            })
145    }
146}
cgroups_rs/net_prio.rs

cgroups_rs/
net_prio.rs
