starnix_core/bpf/
mod.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5//! Implementation of (e)BPF.
6//!
7//! BPF stands for Berkeley Packet Filter and is an API introduced in BSD that allows filtering
8//! network packets by running little programs in the kernel. eBPF stands for extended BFP and
9//! is a Linux extension of BPF that allows hooking BPF programs into many different
10//! non-networking-related contexts.
11
12pub mod attachments;
13pub mod context;
14pub mod fs;
15pub mod map;
16pub mod program;
17pub mod syscalls;
18
19use crate::bpf::attachments::EbpfAttachments;
20use crate::bpf::map::{BpfMapHandle, BpfMapId, WeakBpfMapHandle};
21use crate::bpf::program::{ProgramHandle, ProgramId, WeakProgramHandle};
22use starnix_sync::{EbpfStateLock, LockDepMutex};
23use starnix_uapi::{bpf_map_type, bpf_map_type_BPF_MAP_TYPE_SK_STORAGE};
24use std::collections::BTreeMap;
25use std::ops::Bound;
26use std::sync::Arc;
27use zerocopy::IntoBytes as _;
28
29struct WeakMapWithType {
30    map_type: bpf_map_type,
31    weak_map: WeakBpfMapHandle,
32}
33
34impl WeakMapWithType {
35    fn new(map: &BpfMapHandle) -> Self {
36        Self { map_type: map.schema.map_type, weak_map: Arc::downgrade(map) }
37    }
38}
39
40/// Stores global eBPF state.
41#[derive(Default)]
42pub struct EbpfState {
43    pub attachments: EbpfAttachments,
44
45    programs: LockDepMutex<BTreeMap<ProgramId, WeakProgramHandle>, EbpfStateLock>,
46    maps: LockDepMutex<BTreeMap<BpfMapId, WeakMapWithType>, EbpfStateLock>,
47}
48
49impl EbpfState {
50    fn register_program(&self, program: &ProgramHandle) {
51        self.programs.lock().insert(program.id(), Arc::downgrade(program));
52    }
53
54    fn unregister_program(&self, id: ProgramId) {
55        self.programs.lock().remove(&id).expect("Missing eBPF program");
56    }
57
58    fn get_next_program_id(&self, start_id: ProgramId) -> Option<ProgramId> {
59        self.programs
60            .lock()
61            .range((Bound::Excluded(start_id), Bound::Unbounded))
62            .next()
63            .map(|(k, _)| *k)
64    }
65
66    fn get_program_by_id(&self, id: ProgramId) -> Option<ProgramHandle> {
67        self.programs.lock().get(&id).map(|p| p.upgrade()).flatten()
68    }
69
70    fn register_map(&self, map: &BpfMapHandle) {
71        self.maps.lock().insert(map.id(), WeakMapWithType::new(map));
72    }
73
74    fn unregister_map(&self, id: BpfMapId) {
75        self.maps.lock().remove(&id).expect("Missing eBPF map");
76    }
77
78    fn get_next_map_id(&self, start_id: BpfMapId) -> Option<BpfMapId> {
79        self.maps
80            .lock()
81            .range((Bound::Excluded(start_id), Bound::Unbounded))
82            .next()
83            .map(|(k, _)| *k)
84    }
85
86    fn get_map_by_id(&self, id: BpfMapId) -> Option<BpfMapHandle> {
87        self.maps.lock().get(&id).map(|entry| entry.weak_map.upgrade()).flatten()
88    }
89
90    /// Removed socket with the specified `cookie` from all `sk_storage` maps.
91    // TODO(https://fxbug.dev/496639039): Move sk_storage cleanup to Netstack.
92    pub fn remove_sk_storage_entries(&self, cookie: u64) {
93        self.maps.lock().iter().for_each(|(_, entry)| {
94            if entry.map_type == bpf_map_type_BPF_MAP_TYPE_SK_STORAGE
95                && let Some(map) = entry.weak_map.upgrade()
96            {
97                let _ = map.delete(cookie.as_bytes());
98            }
99        });
100    }
101}
starnix_core/bpf/mod.rs

starnix_core/bpf/
mod.rs
