-
Notifications
You must be signed in to change notification settings - Fork 247
/
mod.rs
970 lines (881 loc) · 28.8 KB
/
mod.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
//! Data structures used to setup and share data with eBPF programs.
//!
//! The eBPF platform provides data structures - maps in eBPF speak - that are
//! used to setup and share data with eBPF programs. When you call
//! [`Bpf::load_file`](crate::Bpf::load_file) or
//! [`Bpf::load`](crate::Bpf::load), all the maps defined in the eBPF code get
//! initialized and can then be accessed using [`Bpf::map`](crate::Bpf::map),
//! [`Bpf::map_mut`](crate::Bpf::map_mut), or
//! [`Bpf::take_map`](crate::Bpf::take_map).
//!
//! # Typed maps
//!
//! The eBPF API includes many map types each supporting different operations.
//! [`Bpf::map`](crate::Bpf::map), [`Bpf::map_mut`](crate::Bpf::map_mut), and
//! [`Bpf::take_map`](crate::Bpf::take_map) always return the opaque
//! [`&Map`](crate::maps::Map), [`&mut Map`](crate::maps::Map), and [`Map`]
//! types respectively. Those three types can be converted to *typed maps* using
//! the [`TryFrom`] or [`TryInto`] trait. For example:
//!
//! ```no_run
//! # #[derive(Debug, thiserror::Error)]
//! # enum Error {
//! # #[error(transparent)]
//! # IO(#[from] std::io::Error),
//! # #[error(transparent)]
//! # Map(#[from] aya::maps::MapError),
//! # #[error(transparent)]
//! # Program(#[from] aya::programs::ProgramError),
//! # #[error(transparent)]
//! # Bpf(#[from] aya::BpfError)
//! # }
//! # let mut bpf = aya::Bpf::load(&[])?;
//! use aya::maps::SockMap;
//! use aya::programs::SkMsg;
//!
//! let intercept_egress = SockMap::try_from(bpf.map_mut("INTERCEPT_EGRESS").unwrap())?;
//! let map_fd = intercept_egress.fd().try_clone()?;
//! let prog: &mut SkMsg = bpf.program_mut("intercept_egress_packet").unwrap().try_into()?;
//! prog.load()?;
//! prog.attach(&map_fd)?;
//!
//! # Ok::<(), Error>(())
//! ```
//!
//! # Maps and `Pod` values
//!
//! Many map operations copy data from kernel space to user space and vice
//! versa. Because of that, all map values must be plain old data and therefore
//! implement the [Pod] trait.
use std::{
borrow::BorrowMut,
ffi::{c_long, CString},
fmt, io,
marker::PhantomData,
mem,
ops::Deref,
os::fd::{AsFd, BorrowedFd, OwnedFd},
path::Path,
ptr,
};
use libc::{getrlimit, rlim_t, rlimit, RLIMIT_MEMLOCK, RLIM_INFINITY};
use log::warn;
use obj::maps::InvalidMapTypeError;
use thiserror::Error;
use crate::{
obj::{self, parse_map_info, BpfSectionKind},
pin::PinError,
sys::{
bpf_create_map, bpf_get_object, bpf_map_freeze, bpf_map_get_info_by_fd,
bpf_map_get_next_key, bpf_map_update_elem_ptr, bpf_pin_object, SyscallError,
},
util::{nr_cpus, KernelVersion},
PinningType, Pod,
};
pub mod array;
pub mod bloom_filter;
pub mod hash_map;
pub mod lpm_trie;
pub mod perf;
pub mod queue;
pub mod ring_buf;
pub mod sock;
pub mod stack;
pub mod stack_trace;
pub mod xdp;
pub use array::{Array, PerCpuArray, ProgramArray};
pub use bloom_filter::BloomFilter;
pub use hash_map::{HashMap, PerCpuHashMap};
pub use lpm_trie::LpmTrie;
#[cfg(any(feature = "async_tokio", feature = "async_std"))]
#[cfg_attr(docsrs, doc(cfg(any(feature = "async_tokio", feature = "async_std"))))]
pub use perf::AsyncPerfEventArray;
pub use perf::PerfEventArray;
pub use queue::Queue;
pub use ring_buf::RingBuf;
pub use sock::{SockHash, SockMap};
pub use stack::Stack;
pub use stack_trace::StackTraceMap;
pub use xdp::{CpuMap, DevMap, DevMapHash, XskMap};
#[derive(Error, Debug)]
/// Errors occuring from working with Maps
pub enum MapError {
/// Invalid map type encontered
#[error("invalid map type {map_type}")]
InvalidMapType {
/// The map type
map_type: u32,
},
/// Invalid map name encountered
#[error("invalid map name `{name}`")]
InvalidName {
/// The map name
name: String,
},
/// Failed to create map
#[error("failed to create map `{name}` with code {code}")]
CreateError {
/// Map name
name: String,
/// Error code
code: c_long,
#[source]
/// Original io::Error
io_error: io::Error,
},
/// Invalid key size
#[error("invalid key size {size}, expected {expected}")]
InvalidKeySize {
/// Size encountered
size: usize,
/// Size expected
expected: usize,
},
/// Invalid value size
#[error("invalid value size {size}, expected {expected}")]
InvalidValueSize {
/// Size encountered
size: usize,
/// Size expected
expected: usize,
},
/// Index is out of bounds
#[error("the index is {index} but `max_entries` is {max_entries}")]
OutOfBounds {
/// Index accessed
index: u32,
/// Map size
max_entries: u32,
},
/// Key not found
#[error("key not found")]
KeyNotFound,
/// Element not found
#[error("element not found")]
ElementNotFound,
/// Progam Not Loaded
#[error("the program is not loaded")]
ProgramNotLoaded,
/// Syscall failed
#[error(transparent)]
SyscallError(#[from] SyscallError),
/// Could not pin map
#[error("map `{name:?}` requested pinning. pinning failed")]
PinError {
/// The map name
name: Option<String>,
/// The reason for the failure
#[source]
error: PinError,
},
/// Program IDs are not supported
#[error("program ids are not supported by the current kernel")]
ProgIdNotSupported,
/// Unsupported Map type
#[error("Unsupported map type found {map_type}")]
Unsupported {
/// The map type
map_type: u32,
},
}
// Note that this is not just derived using #[from] because InvalidMapTypeError cannot implement
// Error due the the fact that aya-obj is no_std and error_in_core is not stabilized
// (https://github.com/rust-lang/rust/issues/103765).
impl From<InvalidMapTypeError> for MapError {
fn from(e: InvalidMapTypeError) -> Self {
let InvalidMapTypeError { map_type } = e;
Self::InvalidMapType { map_type }
}
}
/// A map file descriptor.
#[derive(Debug)]
pub struct MapFd(OwnedFd);
impl AsFd for MapFd {
fn as_fd(&self) -> BorrowedFd<'_> {
let Self(fd) = self;
fd.as_fd()
}
}
/// Raises a warning about rlimit. Should be used only if creating a map was not
/// successful.
fn maybe_warn_rlimit() {
let mut limit = std::mem::MaybeUninit::<rlimit>::uninit();
let ret = unsafe { getrlimit(RLIMIT_MEMLOCK, limit.as_mut_ptr()) };
if ret == 0 {
let limit = unsafe { limit.assume_init() };
if limit.rlim_cur == RLIM_INFINITY {
return;
}
struct HumanSize(rlim_t);
impl fmt::Display for HumanSize {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let &Self(size) = self;
if size < 1024 {
write!(f, "{} bytes", size)
} else if size < 1024 * 1024 {
write!(f, "{} KiB", size / 1024)
} else {
write!(f, "{} MiB", size / 1024 / 1024)
}
}
}
warn!(
"RLIMIT_MEMLOCK value is {}, not RLIM_INFINITY; if experiencing problems with creating \
maps, try raising RLIMIT_MEMLOCK either to RLIM_INFINITY or to a higher value sufficient \
for the size of your maps",
HumanSize(limit.rlim_cur)
);
}
}
/// eBPF map types.
#[derive(Debug)]
pub enum Map {
/// An [`Array`] map.
Array(MapData),
/// A [`BloomFilter`] map.
BloomFilter(MapData),
/// A [`CpuMap`] map.
CpuMap(MapData),
/// A [`DevMap`] map.
DevMap(MapData),
/// A [`DevMapHash`] map.
DevMapHash(MapData),
/// A [`HashMap`] map.
HashMap(MapData),
/// A [`LpmTrie`] map.
LpmTrie(MapData),
/// A [`HashMap`] map that uses a LRU eviction policy.
LruHashMap(MapData),
/// A [`PerCpuArray`] map.
PerCpuArray(MapData),
/// A [`PerCpuHashMap`] map.
PerCpuHashMap(MapData),
/// A [`PerCpuHashMap`] map that uses a LRU eviction policy.
PerCpuLruHashMap(MapData),
/// A [`PerfEventArray`] map.
PerfEventArray(MapData),
/// A [`ProgramArray`] map.
ProgramArray(MapData),
/// A [`Queue`] map.
Queue(MapData),
/// A [`RingBuf`] map.
RingBuf(MapData),
/// A [`SockHash`] map
SockHash(MapData),
/// A [`SockMap`] map.
SockMap(MapData),
/// A [`Stack`] map.
Stack(MapData),
/// A [`StackTraceMap`] map.
StackTraceMap(MapData),
/// An unsupported map type.
Unsupported(MapData),
/// A [`XskMap`] map.
XskMap(MapData),
}
impl Map {
/// Returns the low level map type.
fn map_type(&self) -> u32 {
match self {
Self::Array(map) => map.obj.map_type(),
Self::BloomFilter(map) => map.obj.map_type(),
Self::CpuMap(map) => map.obj.map_type(),
Self::DevMap(map) => map.obj.map_type(),
Self::DevMapHash(map) => map.obj.map_type(),
Self::HashMap(map) => map.obj.map_type(),
Self::LpmTrie(map) => map.obj.map_type(),
Self::LruHashMap(map) => map.obj.map_type(),
Self::PerCpuArray(map) => map.obj.map_type(),
Self::PerCpuHashMap(map) => map.obj.map_type(),
Self::PerCpuLruHashMap(map) => map.obj.map_type(),
Self::PerfEventArray(map) => map.obj.map_type(),
Self::ProgramArray(map) => map.obj.map_type(),
Self::Queue(map) => map.obj.map_type(),
Self::RingBuf(map) => map.obj.map_type(),
Self::SockHash(map) => map.obj.map_type(),
Self::SockMap(map) => map.obj.map_type(),
Self::Stack(map) => map.obj.map_type(),
Self::StackTraceMap(map) => map.obj.map_type(),
Self::Unsupported(map) => map.obj.map_type(),
Self::XskMap(map) => map.obj.map_type(),
}
}
/// Pins the map to a BPF filesystem.
///
/// When a map is pinned it will remain loaded until the corresponding file
/// is deleted. All parent directories in the given `path` must already exist.
pub fn pin<P: AsRef<Path>>(&mut self, path: P) -> Result<(), PinError> {
match self {
Self::Array(map) => map.pin(path),
Self::BloomFilter(map) => map.pin(path),
Self::CpuMap(map) => map.pin(path),
Self::DevMap(map) => map.pin(path),
Self::DevMapHash(map) => map.pin(path),
Self::HashMap(map) => map.pin(path),
Self::LpmTrie(map) => map.pin(path),
Self::LruHashMap(map) => map.pin(path),
Self::PerCpuArray(map) => map.pin(path),
Self::PerCpuHashMap(map) => map.pin(path),
Self::PerCpuLruHashMap(map) => map.pin(path),
Self::PerfEventArray(map) => map.pin(path),
Self::ProgramArray(map) => map.pin(path),
Self::Queue(map) => map.pin(path),
Self::RingBuf(map) => map.pin(path),
Self::SockHash(map) => map.pin(path),
Self::SockMap(map) => map.pin(path),
Self::Stack(map) => map.pin(path),
Self::StackTraceMap(map) => map.pin(path),
Self::Unsupported(map) => map.pin(path),
Self::XskMap(map) => map.pin(path),
}
}
}
// Implements map pinning for different map implementations
// TODO add support for PerfEventArrays and AsyncPerfEventArrays
macro_rules! impl_map_pin {
($ty_param:tt {
$($ty:ident),+ $(,)?
}) => {
$(impl_map_pin!(<$ty_param> $ty);)+
};
(
<($($ty_param:ident),*)>
$ty:ident
) => {
impl<T: BorrowMut<MapData>, $($ty_param: Pod),*> $ty<T, $($ty_param),*>
{
/// Pins the map to a BPF filesystem.
///
/// When a map is pinned it will remain loaded until the corresponding file
/// is deleted. All parent directories in the given `path` must already exist.
pub fn pin<P: AsRef<Path>>(&mut self, path: P) -> Result<(), PinError> {
let data = self.inner.borrow_mut();
data.pin(path)
}
}
};
}
impl_map_pin!(() {
ProgramArray,
SockMap,
StackTraceMap,
CpuMap,
DevMap,
DevMapHash,
XskMap,
});
impl_map_pin!((V) {
Array,
PerCpuArray,
SockHash,
BloomFilter,
Queue,
Stack,
});
impl_map_pin!((K, V) {
HashMap,
PerCpuHashMap,
LpmTrie,
});
// Implements TryFrom<Map> for different map implementations. Different map implementations can be
// constructed from different variants of the map enum. Also, the implementation may have type
// parameters (which we assume all have the bound `Pod` and nothing else).
macro_rules! impl_try_from_map {
// At the root the type parameters are marked as a single token tree which will be pasted into
// the invocation for each type. Note that the later patterns require that the token tree be
// zero or more comma separated idents wrapped in parens. Note that the tt metavar is used here
// rather than the repeated idents used later because the macro language does not allow one
// repetition to be pasted inside another.
($ty_param:tt {
$($ty:ident $(from $($variant:ident)|+)?),+ $(,)?
}) => {
$(impl_try_from_map!(<$ty_param> $ty $(from $($variant)|+)?);)+
};
// Add the "from $variant" using $ty as the default if it is missing.
(<$ty_param:tt> $ty:ident) => {
impl_try_from_map!(<$ty_param> $ty from $ty);
};
// Dispatch for each of the lifetimes.
(
<($($ty_param:ident),*)> $ty:ident from $($variant:ident)|+
) => {
impl_try_from_map!(<'a> ($($ty_param),*) $ty from $($variant)|+);
impl_try_from_map!(<'a mut> ($($ty_param),*) $ty from $($variant)|+);
impl_try_from_map!(<> ($($ty_param),*) $ty from $($variant)|+);
};
// An individual impl.
(
<$($l:lifetime $($m:ident)?)?>
($($ty_param:ident),*)
$ty:ident from $($variant:ident)|+
) => {
impl<$($l,)? $($ty_param: Pod),*> TryFrom<$(&$l $($m)?)? Map>
for $ty<$(&$l $($m)?)? MapData, $($ty_param),*>
{
type Error = MapError;
fn try_from(map: $(&$l $($m)?)? Map) -> Result<Self, Self::Error> {
match map {
$(Map::$variant(map_data) => Self::new(map_data),)+
map => Err(MapError::InvalidMapType {
map_type: map.map_type()
}),
}
}
}
};
}
impl_try_from_map!(() {
CpuMap,
DevMap,
DevMapHash,
PerfEventArray,
ProgramArray,
RingBuf,
SockMap,
StackTraceMap,
XskMap,
});
#[cfg(any(feature = "async_tokio", feature = "async_std"))]
#[cfg_attr(docsrs, doc(cfg(any(feature = "async_tokio", feature = "async_std"))))]
impl_try_from_map!(() {
AsyncPerfEventArray from PerfEventArray,
});
impl_try_from_map!((V) {
Array,
BloomFilter,
PerCpuArray,
Queue,
SockHash,
Stack,
});
impl_try_from_map!((K, V) {
HashMap from HashMap|LruHashMap,
LpmTrie,
PerCpuHashMap from PerCpuHashMap|PerCpuLruHashMap,
});
pub(crate) fn check_bounds(map: &MapData, index: u32) -> Result<(), MapError> {
let max_entries = map.obj.max_entries();
if index >= max_entries {
Err(MapError::OutOfBounds { index, max_entries })
} else {
Ok(())
}
}
pub(crate) fn check_kv_size<K, V>(map: &MapData) -> Result<(), MapError> {
let size = mem::size_of::<K>();
let expected = map.obj.key_size() as usize;
if size != expected {
return Err(MapError::InvalidKeySize { size, expected });
}
let size = mem::size_of::<V>();
let expected = map.obj.value_size() as usize;
if size != expected {
return Err(MapError::InvalidValueSize { size, expected });
};
Ok(())
}
pub(crate) fn check_v_size<V>(map: &MapData) -> Result<(), MapError> {
let size = mem::size_of::<V>();
let expected = map.obj.value_size() as usize;
if size != expected {
return Err(MapError::InvalidValueSize { size, expected });
};
Ok(())
}
/// A generic handle to a BPF map.
///
/// You should never need to use this unless you're implementing a new map type.
#[derive(Debug)]
pub struct MapData {
obj: obj::Map,
fd: MapFd,
}
impl MapData {
/// Creates a new map with the provided `name`
pub fn create(
obj: obj::Map,
name: &str,
btf_fd: Option<BorrowedFd<'_>>,
) -> Result<Self, MapError> {
let c_name = CString::new(name).map_err(|_| MapError::InvalidName { name: name.into() })?;
#[cfg(not(test))]
let kernel_version = KernelVersion::current().unwrap();
#[cfg(test)]
let kernel_version = KernelVersion::new(0xff, 0xff, 0xff);
let fd =
bpf_create_map(&c_name, &obj, btf_fd, kernel_version).map_err(|(code, io_error)| {
if kernel_version < KernelVersion::new(5, 11, 0) {
maybe_warn_rlimit();
}
MapError::CreateError {
name: name.into(),
code,
io_error,
}
})?;
let fd = MapFd(fd);
Ok(Self { obj, fd })
}
pub(crate) fn create_pinned_by_name<P: AsRef<Path>>(
path: P,
obj: obj::Map,
name: &str,
btf_fd: Option<BorrowedFd<'_>>,
) -> Result<Self, MapError> {
use std::os::unix::ffi::OsStrExt as _;
// try to open map in case it's already pinned
let path = path.as_ref().join(name);
let path_string = match CString::new(path.as_os_str().as_bytes()) {
Ok(path) => path,
Err(error) => {
return Err(MapError::PinError {
name: Some(name.into()),
error: PinError::InvalidPinPath { path, error },
});
}
};
match bpf_get_object(&path_string).map_err(|(_, io_error)| SyscallError {
call: "BPF_OBJ_GET",
io_error,
}) {
Ok(fd) => {
let fd = MapFd(fd);
Ok(Self { obj, fd })
}
Err(_) => {
let mut map = Self::create(obj, name, btf_fd)?;
map.pin(&path).map_err(|error| MapError::PinError {
name: Some(name.into()),
error,
})?;
Ok(map)
}
}
}
pub(crate) fn finalize(&mut self) -> Result<(), MapError> {
let Self { obj, fd } = self;
if !obj.data().is_empty() && obj.section_kind() != BpfSectionKind::Bss {
bpf_map_update_elem_ptr(fd.as_fd(), &0 as *const _, obj.data_mut().as_mut_ptr(), 0)
.map_err(|(_, io_error)| SyscallError {
call: "bpf_map_update_elem",
io_error,
})
.map_err(MapError::from)?;
}
if obj.section_kind() == BpfSectionKind::Rodata {
bpf_map_freeze(fd.as_fd())
.map_err(|(_, io_error)| SyscallError {
call: "bpf_map_freeze",
io_error,
})
.map_err(MapError::from)?;
}
Ok(())
}
/// Loads a map from a pinned path in bpffs.
pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, MapError> {
use std::os::unix::ffi::OsStrExt as _;
let path = path.as_ref();
let path_string =
CString::new(path.as_os_str().as_bytes()).map_err(|error| MapError::PinError {
name: None,
error: PinError::InvalidPinPath {
path: path.into(),
error,
},
})?;
let fd = bpf_get_object(&path_string).map_err(|(_, io_error)| SyscallError {
call: "BPF_OBJ_GET",
io_error,
})?;
let fd = MapFd(fd);
let info = bpf_map_get_info_by_fd(fd.as_fd())?;
Ok(Self {
obj: parse_map_info(info, PinningType::ByName),
fd,
})
}
/// Loads a map from a file descriptor.
///
/// If loading from a BPF Filesystem (bpffs) you should use [`Map::from_pin`](crate::maps::MapData::from_pin).
/// This API is intended for cases where you have received a valid BPF FD from some other means.
/// For example, you received an FD over Unix Domain Socket.
pub fn from_fd(fd: OwnedFd) -> Result<Self, MapError> {
let info = bpf_map_get_info_by_fd(fd.as_fd())?;
let fd = MapFd(fd);
Ok(Self {
obj: parse_map_info(info, PinningType::None),
fd,
})
}
/// Allows the map to be pinned to the provided path.
///
/// Any directories in the the path provided should have been created by the caller.
/// The path must be on a BPF filesystem.
///
/// # Errors
///
/// Returns a [`PinError::SyscallError`] if the underlying syscall fails.
/// This may also happen if the path already exists, in which case the wrapped
/// [`std::io::Error`] kind will be [`std::io::ErrorKind::AlreadyExists`].
/// Returns a [`PinError::InvalidPinPath`] if the path provided cannot be
/// converted to a [`CString`].
///
/// # Example
///
/// ```no_run
/// # let mut bpf = aya::Bpf::load(&[])?;
/// # use aya::maps::MapData;
///
/// let mut map = MapData::from_pin("/sys/fs/bpf/my_map")?;
/// map.pin("/sys/fs/bpf/my_map2")?;
///
/// # Ok::<(), Box<dyn std::error::Error>>(())
/// ```
pub fn pin<P: AsRef<Path>>(&mut self, path: P) -> Result<(), PinError> {
use std::os::unix::ffi::OsStrExt as _;
let Self { fd, obj: _ } = self;
let path = path.as_ref();
let path_string = CString::new(path.as_os_str().as_bytes()).map_err(|error| {
PinError::InvalidPinPath {
path: path.to_path_buf(),
error,
}
})?;
bpf_pin_object(fd.as_fd(), &path_string).map_err(|(_, io_error)| SyscallError {
call: "BPF_OBJ_PIN",
io_error,
})?;
Ok(())
}
/// Returns the file descriptor of the map.
pub fn fd(&self) -> &MapFd {
let Self { obj: _, fd } = self;
fd
}
pub(crate) fn obj(&self) -> &obj::Map {
let Self { obj, fd: _ } = self;
obj
}
}
/// An iterable map
pub trait IterableMap<K: Pod, V> {
/// Get a generic map handle
fn map(&self) -> &MapData;
/// Get the value for the provided `key`
fn get(&self, key: &K) -> Result<V, MapError>;
}
/// Iterator returned by `map.keys()`.
pub struct MapKeys<'coll, K: Pod> {
map: &'coll MapData,
err: bool,
key: Option<K>,
}
impl<'coll, K: Pod> MapKeys<'coll, K> {
fn new(map: &'coll MapData) -> Self {
Self {
map,
err: false,
key: None,
}
}
}
impl<K: Pod> Iterator for MapKeys<'_, K> {
type Item = Result<K, MapError>;
fn next(&mut self) -> Option<Result<K, MapError>> {
if self.err {
return None;
}
let fd = self.map.fd().as_fd();
let key =
bpf_map_get_next_key(fd, self.key.as_ref()).map_err(|(_, io_error)| SyscallError {
call: "bpf_map_get_next_key",
io_error,
});
match key {
Err(err) => {
self.err = true;
Some(Err(err.into()))
}
Ok(key) => {
self.key = key;
key.map(Ok)
}
}
}
}
/// Iterator returned by `map.iter()`.
pub struct MapIter<'coll, K: Pod, V, I: IterableMap<K, V>> {
keys: MapKeys<'coll, K>,
map: &'coll I,
_v: PhantomData<V>,
}
impl<'coll, K: Pod, V, I: IterableMap<K, V>> MapIter<'coll, K, V, I> {
fn new(map: &'coll I) -> Self {
Self {
keys: MapKeys::new(map.map()),
map,
_v: PhantomData,
}
}
}
impl<K: Pod, V, I: IterableMap<K, V>> Iterator for MapIter<'_, K, V, I> {
type Item = Result<(K, V), MapError>;
fn next(&mut self) -> Option<Self::Item> {
loop {
match self.keys.next() {
Some(Ok(key)) => match self.map.get(&key) {
Ok(value) => return Some(Ok((key, value))),
Err(MapError::KeyNotFound) => continue,
Err(e) => return Some(Err(e)),
},
Some(Err(e)) => return Some(Err(e)),
None => return None,
}
}
}
}
pub(crate) struct PerCpuKernelMem {
bytes: Vec<u8>,
}
impl PerCpuKernelMem {
pub(crate) fn as_mut_ptr(&mut self) -> *mut u8 {
self.bytes.as_mut_ptr()
}
}
/// A slice of per-CPU values.
///
/// Used by maps that implement per-CPU storage like [`PerCpuHashMap`].
///
/// # Examples
///
/// ```no_run
/// # #[derive(thiserror::Error, Debug)]
/// # enum Error {
/// # #[error(transparent)]
/// # IO(#[from] std::io::Error),
/// # #[error(transparent)]
/// # Map(#[from] aya::maps::MapError),
/// # #[error(transparent)]
/// # Bpf(#[from] aya::BpfError)
/// # }
/// # let bpf = aya::Bpf::load(&[])?;
/// use aya::maps::PerCpuValues;
/// use aya::util::nr_cpus;
///
/// let values = PerCpuValues::try_from(vec![42u32; nr_cpus()?])?;
/// # Ok::<(), Error>(())
/// ```
#[derive(Debug)]
pub struct PerCpuValues<T: Pod> {
values: Box<[T]>,
}
impl<T: Pod> TryFrom<Vec<T>> for PerCpuValues<T> {
type Error = io::Error;
fn try_from(values: Vec<T>) -> Result<Self, Self::Error> {
let nr_cpus = nr_cpus()?;
if values.len() != nr_cpus {
return Err(io::Error::new(
io::ErrorKind::InvalidInput,
format!("not enough values ({}), nr_cpus: {}", values.len(), nr_cpus),
));
}
Ok(Self {
values: values.into_boxed_slice(),
})
}
}
impl<T: Pod> PerCpuValues<T> {
pub(crate) fn alloc_kernel_mem() -> Result<PerCpuKernelMem, io::Error> {
let value_size = (mem::size_of::<T>() + 7) & !7;
Ok(PerCpuKernelMem {
bytes: vec![0u8; nr_cpus()? * value_size],
})
}
pub(crate) unsafe fn from_kernel_mem(mem: PerCpuKernelMem) -> Self {
let mem_ptr = mem.bytes.as_ptr() as usize;
let value_size = (mem::size_of::<T>() + 7) & !7;
let mut values = Vec::new();
let mut offset = 0;
while offset < mem.bytes.len() {
values.push(ptr::read_unaligned((mem_ptr + offset) as *const _));
offset += value_size;
}
Self {
values: values.into_boxed_slice(),
}
}
pub(crate) fn build_kernel_mem(&self) -> Result<PerCpuKernelMem, io::Error> {
let mut mem = Self::alloc_kernel_mem()?;
let mem_ptr = mem.as_mut_ptr() as usize;
let value_size = (mem::size_of::<T>() + 7) & !7;
for i in 0..self.values.len() {
unsafe { ptr::write_unaligned((mem_ptr + i * value_size) as *mut _, self.values[i]) };
}
Ok(mem)
}
}
impl<T: Pod> Deref for PerCpuValues<T> {
type Target = Box<[T]>;
fn deref(&self) -> &Self::Target {
&self.values
}
}
#[cfg(test)]
mod tests {
use std::os::fd::AsRawFd as _;
use assert_matches::assert_matches;
use libc::EFAULT;
use super::*;
use crate::{
bpf_map_def,
generated::{bpf_cmd, bpf_map_type::BPF_MAP_TYPE_HASH},
maps::MapData,
obj::{maps::LegacyMap, BpfSectionKind},
sys::{override_syscall, Syscall},
};
fn new_obj_map() -> obj::Map {
obj::Map::Legacy(LegacyMap {
def: bpf_map_def {
map_type: BPF_MAP_TYPE_HASH as u32,
key_size: 4,
value_size: 4,
max_entries: 1024,
..Default::default()
},
section_index: 0,
section_kind: BpfSectionKind::Maps,
symbol_index: Some(0),
data: Vec::new(),
})
}
#[test]
fn test_create() {
override_syscall(|call| match call {
Syscall::Bpf {
cmd: bpf_cmd::BPF_MAP_CREATE,
..
} => Ok(42),
_ => Err((-1, io::Error::from_raw_os_error(EFAULT))),
});
assert_matches!(
MapData::create(new_obj_map(), "foo", None),
Ok(MapData {
obj: _,
fd,
}) => assert_eq!(fd.as_fd().as_raw_fd(), 42)
);
}
#[test]
fn test_create_failed() {
override_syscall(|_| Err((-42, io::Error::from_raw_os_error(EFAULT))));
assert_matches!(
MapData::create(new_obj_map(), "foo", None),
Err(MapError::CreateError { name, code, io_error }) => {
assert_eq!(name, "foo");
assert_eq!(code, -42);
assert_eq!(io_error.raw_os_error(), Some(EFAULT));
}
);
}
}