On ppc64le we get the following warning:
In file included from btf_dump.c:16:0:
btf_dump.c: In function ‘btf_dump_emit_struct_def’:
../include/linux/kernel.h:20:17: error: comparison of distinct pointer types lacks a cast [-Werror]
(void) (&_max1 == &_max2); \
^
btf_dump.c:882:11: note: in expansion of macro ‘max’
m_sz = max(0LL, btf__resolve_size(d->btf, m->type));
^~~
Fix by explicitly casting to __s64, which is a return type from
btf__resolve_size().
Fixes: 702eddc77a90 ("libbpf: Handle GCC built-in types for Arm NEON")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818164456.1181661-1-andriin@fb.com
With libbpf and BTF it is pretty common to have libbpf built for one
architecture, while BTF information was generated for a different architecture
(typically, but not always, BPF). In such case, the size of a pointer might
differ betweem architectures. libbpf previously was always making an
assumption that pointer size for BTF is the same as native architecture
pointer size, but that breaks for cases where libbpf is built as 32-bit
library, while BTF is for 64-bit architecture.
To solve this, add heuristic to determine pointer size by searching for `long`
or `unsigned long` integer type and using its size as a pointer size. Also,
allow to override the pointer size with a new API btf__set_pointer_size(), for
cases where application knows which pointer size should be used. User
application can check what libbpf "guessed" by looking at the result of
btf__pointer_size(). If it's not 0, then libbpf successfully determined a
pointer size, otherwise native arch pointer size will be used.
For cases where BTF is parsed from ELF file, use ELF's class (32-bit or
64-bit) to determine pointer size.
Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf")
Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-5-andriin@fb.com
Libbpf built in 32-bit mode should be careful about not conflating 64-bit BPF
pointers in BPF ELF file and host architecture pointers. This patch fixes
issue of incorrect initializating of map-in-map inner map slots due to such
difference.
Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200813204945.1020225-4-andriin@fb.com
When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
DWARF information using a base type "__Poly8_t", which is internal to
GCC and not recognized by Clang. This causes build failures when
building with Clang a vmlinux.h generated from an arm64 kernel that was
built with GCC.
vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
typedef __Poly8_t poly8x16_t[16];
^~~~~~~~~
The polyX_t types are defined as unsigned integers in the "Arm C
Language Extension" document (101028_Q220_00_en). Emit typedefs based on
standard integer types for the GCC internal types, similar to those
emitted by Clang.
Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
max(), causing a build bug due to different types, hence the seemingly
unrelated change.
Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200812143909.3293280-1-jean-philippe@linaro.org
Commit 5fbc220862fc ("tools/libpf: Add offsetof/container_of macro
in bpf_helpers.h") added a macro offsetof() to get the offset of a
structure member:
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
In certain use cases, size_t type may not be available so
Commit da7a35062bcc ("libbpf bpf_helpers: Use __builtin_offsetof
for offsetof") changed to use __builtin_offsetof which removed
the dependency on type size_t, which I suggested.
But using __builtin_offsetof will prevent CO-RE relocation
generation in case that, e.g., TYPE is annotated with "preserve_access_info"
where a relocation is desirable in case the member offset is changed
in a different kernel version. So this patch reverted back to
the original macro but using "unsigned long" instead of "site_t".
Fixes: da7a35062bcc ("libbpf bpf_helpers: Use __builtin_offsetof for offsetof")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/bpf/20200811030852.3396929-1-yhs@fb.com
Do both builds and selftest runs as part of a single build step. This would
allow to complete CI testing faster, as builds will happen in parallel with
"Kernel LATEST + selftests" run.
Also re-enable s390x build.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Attempt to first fetch bpf-next tree from a snapshot, falling back to shallow
clone, and if that is not enough, doing a full bpf-next clone. This should
both improve a speed and (because of full clone fallback) improve test
reliability if libbpf wasn't synced in a while.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Blacklist btf_map_in_map permanently for 5.5. bpf_verif_scale is broken due to
Clang issues on latest. Do not run ALU32 flavor for test_progs on 4.9.0, which
doesn't support ALU32 yet.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Recently, from commit 94a1fedd63ed ("libbpf: Add btf__parse_raw() and
generic btf__parse() APIs"), new API has been added to libbpf that
allows to parse BTF from raw data file (btf__parse_raw()).
The commit derives build failure of samples/bpf due to improper access
of uninitialized pointer at btf_parse_raw().
btf.c: In function btf__parse_raw:
btf.c:625:28: error: btf may be used uninitialized in this function
625 | return err ? ERR_PTR(err) : btf;
| ~~~~~~~~~~~~~~~~~~~^~~~~
This commit fixes the build failure of samples/bpf by adding code of
initializing btf pointer as NULL.
Fixes: 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200805223359.32109-1-danieltimlee@gmail.com
Most of libbpf "constructors" on failure return ERR_PTR(err) result encoded as
a pointer. It's a common mistake to eventually pass such malformed pointers
into xxx__destroy()/xxx__free() "destructors". So instead of fixing up
clean up code in selftests and user programs, handle such error pointers in
destructors themselves. This works beautifully for NULL pointers passed to
destructors, so might as well just work for error pointers.
Suggested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200729232148.896125-1-andriin@fb.com
Whatever happened, clang-11 and llvm-11, to which clang/llvm packages resolve,
respectively, are not there anymore. Seems like clang-12/llvm-12 are the
latest now, but for whatever reason clang/llvm don't resolve to them yet.
Hard-code version 12 for now.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Currently we hardcode "gcc", which means we get a bogus result any time
a non-default CC is passed to Make. In fact, it's bogus even when CC is
not explicitly set, since Make's default is "cc", which isn't
necessarily the same as "gcc".
Fix the issue by passing the compiler to use to check-reallocarray.sh.
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit: 5c3320d7fece4612d4a413aa3c8e82cdb5b49fcb
Checkpoint bpf-next commit: 9a97c9d2af5ca798377342debf7f0f44281d050e
Baseline bpf commit: b2f9f1535bb93ee5fa2ea30ac1c26fa0d676154c
Checkpoint bpf commit: 5b801dfb7feb2738975d80223efc2fc193e55573
Andrii Nakryiko (3):
libbpf: Support stripping modifiers for btf_dump
tools/bpftool: Strip away modifiers from global variables
libbpf: Add support for BPF XDP link
Ciara Loftus (1):
xsk: Add new statistics
Horatiu Vultur (1):
net: bridge: Add port attribute IFLA_BRPORT_MRP_IN_OPEN
Ian Rogers (1):
libbpf bpf_helpers: Use __builtin_offsetof for offsetof
Jakub Sitnicki (2):
bpf: Sync linux/bpf.h to tools/
libbpf: Add support for SK_LOOKUP program type
Lorenzo Bianconi (3):
cpumap: Formalize map value as a named struct
bpf: cpumap: Add the possibility to attach an eBPF program to cpumap
libbpf: Add SEC name for xdp programs attached to CPUMAP
Quentin Monnet (1):
bpf: Fix formatting in documentation for BPF helpers
Randy Dunlap (1):
bpf: Drop duplicated words in uapi helper comments
Song Liu (1):
libbpf: Print hint when PERF_EVENT_IOC_SET_BPF returns -EPROTO
Yonghong Song (2):
bpf: Implement bpf iterator for map elements
tools/libbpf: Add support for bpf map element iterator
include/uapi/linux/bpf.h | 155 +++++++++++++++++++++++++++++------
include/uapi/linux/if_link.h | 1 +
include/uapi/linux/if_xdp.h | 5 +-
src/bpf.c | 1 +
src/bpf.h | 3 +-
src/bpf_helpers.h | 2 +-
src/btf.h | 4 +-
src/btf_dump.c | 10 ++-
src/libbpf.c | 27 +++++-
src/libbpf.h | 7 +-
src/libbpf.map | 3 +
src/libbpf_probes.c | 3 +
12 files changed, 188 insertions(+), 33 deletions(-)
--
2.24.1
Sync UAPI header and add support for using bpf_link-based XDP attachment.
Make xdp/ prog type set expected attach type. Kernel didn't enforce
attach_type for XDP programs before, so there is no backwards compatiblity
issues there.
Also fix section_names selftest to recognize that xdp prog types now have
expected attach type.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-8-andriin@fb.com
The kernel prevents potential unwinder warnings and crashes by blocking
BPF program with bpf_get_[stack|stackid] on perf_event without
PERF_SAMPLE_CALLCHAIN, or with exclude_callchain_[kernel|user]. Print a
hint message in libbpf to help the user debug such issues.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723180648.1429892-4-songliubraving@fb.com
Add map_fd to bpf_iter_attach_opts and flags to
bpf_link_create_opts. Later on, bpftool or selftest
will be able to create a bpf map element iterator
by passing map_fd to the kernel during link
creation time.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184117.590673-1-yhs@fb.com
The bpf iterator for map elements are implemented.
The bpf program will receive four parameters:
bpf_iter_meta *meta: the meta data
bpf_map *map: the bpf_map whose elements are traversed
void *key: the key of one element
void *value: the value of the same element
Here, meta and map pointers are always valid, and
key has register type PTR_TO_RDONLY_BUF_OR_NULL and
value has register type PTR_TO_RDWR_BUF_OR_NULL.
The kernel will track the access range of key and value
during verification time. Later, these values will be compared
against the values in the actual map to ensure all accesses
are within range.
A new field iter_seq_info is added to bpf_map_ops which
is used to add map type specific information, i.e., seq_ops,
init/fini seq_file func and seq_file private data size.
Subsequent patches will have actual implementation
for bpf_map_ops->iter_seq_info.
In user space, BPF_ITER_LINK_MAP_FD needs to be
specified in prog attr->link_create.flags, which indicates
that attr->link_create.target_fd is a map_fd.
The reason for such an explicit flag is for possible
future cases where one bpf iterator may allow more than
one possible customization, e.g., pid and cgroup id for
task_file.
Current kernel internal implementation only allows
the target to register at most one required bpf_iter_link_info.
To support the above case, optional bpf_iter_link_info's
are needed, the target can be extended to register such link
infos, and user provided link_info needs to match one of
target supported ones.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184112.590360-1-yhs@fb.com
The non-builtin route for offsetof has a dependency on size_t from
stdlib.h/stdint.h that is undeclared and may break targets.
The offsetof macro in bpf_helpers may disable the same macro in other
headers that have a #ifdef offsetof guard. Rather than add additional
dependencies improve the offsetof macro declared here to use the
builtin that is available since llvm 3.7 (the first with a BPF backend).
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200720061741.1514673-1-irogers@google.com
Introduce the capability to attach an eBPF program to cpumap entries.
The idea behind this feature is to add the possibility to define on
which CPU run the eBPF program if the underlying hw does not support
RSS. Current supported verdicts are XDP_DROP and XDP_PASS.
This patch has been tested on Marvell ESPRESSObin using xdp_redirect_cpu
sample available in the kernel tree to identify possible performance
regressions. Results show there are no observable differences in
packet-per-second:
$./xdp_redirect_cpu --progname xdp_cpu_map0 --dev eth0 --cpu 1
rx: 354.8 Kpps
rx: 356.0 Kpps
rx: 356.8 Kpps
rx: 356.3 Kpps
rx: 356.6 Kpps
rx: 356.6 Kpps
rx: 356.7 Kpps
rx: 355.8 Kpps
rx: 356.8 Kpps
rx: 356.8 Kpps
Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/5c9febdf903d810b3415732e5cd98491d7d9067a.1594734381.git.lorenzo@kernel.org
This patch adds a new port attribute, IFLA_BRPORT_MRP_IN_OPEN, which
allows to notify the userspace when the node lost the contiuity of
MRP_InTest frames.
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reliably remove all the type modifiers from read-only (.rodata) global
variable definitions, including cases of inner field const modifiers and
arrays of const values.
Also modify one of selftests to ensure that const volatile struct doesn't
prevent user-space from modifying .rodata variable.
Fixes: 985ead416df3 ("bpftool: Add skeleton codegen command")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200713232409.3062144-3-andriin@fb.com
One important use case when emitting const/volatile/restrict is undesirable is
BPF skeleton generation of DATASEC layout. These are further memory-mapped and
can be written/read from user-space directly.
For important case of .rodata variables, bpftool strips away first-level
modifiers, to make their use on user-space side simple and not requiring extra
type casts to override compiler complaining about writing to const variables.
This logic works mostly fine, but breaks in some more complicated cases. E.g.:
const volatile int params[10];
Because in BTF it's a chain of ARRAY -> CONST -> VOLATILE -> INT, bpftool
stops at ARRAY and doesn't strip CONST and VOLATILE. In skeleton this variable
will be emitted as is. So when used from user-space, compiler will complain
about writing to const array. This is problematic, as also mentioned in [0].
To solve this for arrays and other non-trivial cases (e.g., inner
const/volatile fields inside the struct), teach btf_dump to strip away any
modifier, when requested. This is done as an extra option on
btf_dump__emit_type_decl() API.
Reported-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200713232409.3062144-2-andriin@fb.com
It can be useful for the user to know the reason behind a dropped packet.
Introduce new counters which track drops on the receive path caused by:
1. rx ring being full
2. fill ring being empty
Also, on the tx path introduce a counter which tracks the number of times
we attempt pull from the tx ring when it is empty.
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200708072835.4427-2-ciara.loftus@intel.com
Coverity's static analysis helpfully reported a memory leak introduced by
0f0e55d8247c ("libbpf: Improve BTF sanitization handling"). While fixing it,
I realized that btf__new() already creates a memory copy, so there is no need
to do this. So this patch also fixes misleading btf__new() signature to make
data into a `const void *` input parameter. And it avoids unnecessary memory
allocation and copy in BTF sanitization code altogether.
Fixes: 0f0e55d8247c ("libbpf: Improve BTF sanitization handling")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200710011023.1655008-1-andriin@fb.com
On ILP32, 64-bit result was shifted by value calculated for 32-bit long type
and returned value was much outside hashmap capacity.
As advised by Andrii Nakryiko, this patch uses different hashing variant for
architectures with size_t shorter than long long.
Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap")
Signed-off-by: Jakub Bogusz <qboosh@pld-linux.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200709225723.1069937-1-andriin@fb.com
Put selftests in first stage. Put long-running LATEST build & test case first,
so that it can be better parallelized with 4.9 and 5.5.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
perf_buffer__new() is relying on BPF_OBJ_GET_INFO_BY_FD availability for few
sanity checks. OBJ_GET_INFO for maps is actually much more recent feature than
perf_buffer support itself, so this causes unnecessary problems on old kernels
before BPF_OBJ_GET_INFO_BY_FD was added.
This patch makes those sanity checks optional and just assumes best if command
is not supported. If user specified something incorrectly (e.g., wrong map
type), kernel will reject it later anyway, except user won't get a nice
explanation as to why it failed. This seems like a good trade off for
supporting perf_buffer on old kernels.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200708015318.3827358-6-andriin@fb.com
Change sanitization process to preserve original BTF, which might be used by
libbpf itself for Kconfig externs, CO-RE relocs, etc, even if kernel is old
and doesn't support BTF. To achieve that, if libbpf detects the need for BTF
sanitization, it would clone original BTF, sanitize it in-place, attempt to
load it into kernel, and if successful, will preserve loaded BTF FD in
original `struct btf`, while freeing sanitized local copy.
If kernel doesn't support any BTF, original btf and btf_ext will still be
preserved to be used later for CO-RE relocation and other BTF-dependent libbpf
features, which don't dependon kernel BTF support.
Patch takes care to not specify BTF and BTF.ext features when loading BPF
programs and/or maps, if it was detected that kernel doesn't support BTF
features.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200708015318.3827358-4-andriin@fb.com
Add setter for BTF FD to allow application more fine-grained control in more
advanced scenarios. Storing BTF FD inside `struct btf` provides little benefit
and probably would be better done differently (e.g., btf__load() could just
return FD on success), but we are stuck with this due to backwards
compatibility. The main problem is that it's impossible to load BTF and than
free user-space memory, but keep FD intact, because `struct btf` assumes
ownership of that FD upon successful load and will attempt to close it during
btf__free(). To allow callers (e.g., libbpf itself for BTF sanitization) to
have more control over this, add btf__set_fd() to allow to reset FD
arbitrarily, if necessary.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200708015318.3827358-3-andriin@fb.com
With valid ELF and valid BTF, there is no reason (apart from bugs) why BTF
finalization should fail. So make it strict and return error if it fails. This
makes CO-RE relocation more reliable, as they are not going to be just
silently skipped, if BTF finalization failed.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200708015318.3827358-2-andriin@fb.com
Drop blacklist and instead use a small whitelist of tests that are still
supposed to work on old 4.9 kernel.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Make sure that libbpf sanitizes BTF properly for older kernels.
Add a stage for 4.9.0 kernel in TravisCI.
For now make test failures non-blocking by adding 4.9.0 to `allow_failures`
section.
Blacklist is copy-pasted 5.5.0 kernel blacklist.
Now that pre-generated vmlinux.h is used for compilation of non-latest tests,
we don't need custom adjustments for 5.5 kernel selftests. Adjust blacklist
now that those new self-tests are built into test_progs.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Introduce helper bpf_get_task_stack(), which dumps stack trace of given
task. This is different to bpf_get_stack(), which gets stack track of
current task. One potential use case of bpf_get_task_stack() is to call
it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file.
bpf_get_task_stack() uses stack_trace_save_tsk() instead of
get_perf_callchain() for kernel stack. The benefit of this choice is that
stack_trace_save_tsk() doesn't require changes in arch/. The downside of
using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the
stack trace to unsigned long array. For 32-bit systems, we need to
translate it to u64 array.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630062846.664389-3-songliubraving@fb.com
Make bpf_endian.h compatible with vmlinux.h. It is a frequent request from
users wanting to use bpf_endian.h in their BPF applications using CO-RE and
vmlinux.h.
To achieve that, re-implement byte swap macros and drop all the header
includes. This way it can be used both with linux header includes, as well as
with a vmlinux.h.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200630152125.3631920-2-andriin@fb.com
Manually generate vmlinux.h based on latest.config to be used for non-latest
selftest build. This will keep bpftool and newest selftests builds succeeding,
while at runtime blacklist will skip them.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
When producing the bpf-helpers.7 man page from the documentation from
the BPF user space header file, rst2man complains:
<stdin>:2636: (ERROR/3) Unexpected indentation.
<stdin>:2640: (WARNING/2) Block quote ends without a blank line; unexpected unindent.
Let's fix formatting for the relevant chunk (item list in
bpf_ringbuf_query()'s description), and for a couple other functions.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200623153935.6215-1-quentin@isovalent.com
bpf_object__find_program_by_title(), used by CO-RE relocation code, doesn't
return .text "BPF program", if it is a function storage for sub-programs.
Because of that, any CO-RE relocation in helper non-inlined functions will
fail. Fix this by searching for .text-corresponding BPF program manually.
Adjust one of bpf_iter selftest to exhibit this pattern.
Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200619230423.691274-1-andriin@fb.com
Currently, bpf_object__load() (and by induction skeleton's load), will always
attempt to prepare, relocate, and load into kernel every single BPF program
found inside the BPF object file. This is often convenient and the right thing
to do and what users expect.
But there are plenty of cases (especially with BPF development constantly
picking up the pace), where BPF application is intended to work with old
kernels, with potentially reduced set of features. But on kernels supporting
extra features, it would like to take a full advantage of them, by employing
extra BPF program. This could be a choice of using fentry/fexit over
kprobe/kretprobe, if kernel is recent enough and is built with BTF. Or BPF
program might be providing optimized bpf_iter-based solution that user-space
might want to use, whenever available. And so on.
With libbpf and BPF CO-RE in particular, it's advantageous to not have to
maintain two separate BPF object files to achieve this. So to enable such use
cases, this patch adds ability to request not auto-loading chosen BPF
programs. In such case, libbpf won't attempt to perform relocations (which
might fail due to old kernel), won't try to resolve BTF types for
BTF-aware (tp_btf/fentry/fexit/etc) program types, because BTF might not be
present, and so on. Skeleton will also automatically skip auto-attachment step
for such not loaded BPF programs.
Overall, this feature allows to simplify development and deployment of
real-world BPF applications with complicated compatibility requirements.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200625232629.3444003-2-andriin@fb.com
The helper is used in tracing programs to cast a socket
pointer to a tcp6_sock pointer.
The return value could be NULL if the casting is illegal.
A new helper return type RET_PTR_TO_BTF_ID_OR_NULL is added
so the verifier is able to deduce proper return types for the helper.
Different from the previous BTF_ID based helpers,
the bpf_skc_to_tcp6_sock() argument can be several possible
btf_ids. More specifically, all possible socket data structures
with sock_common appearing in the first in the memory layout.
This patch only added socket types related to tcp and udp.
All possible argument btf_id and return value btf_id
for helper bpf_skc_to_tcp6_sock() are pre-calculcated and
cached. In the future, it is even possible to precompute
these btf_id's at kernel build time.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230809.3988195-1-yhs@fb.com
This patch adds support of SO_KEEPALIVE flag and TCP related options
to bpf_setsockopt() routine. This is helpful if we want to enable or tune
TCP keepalive for applications which don't do it in the userspace code.
v3:
- update kernel-doc in uapi (Nikita Vetoshkin <nekto0n@yandex-team.ru>)
v4:
- update kernel-doc in tools too (Alexei Starovoitov)
- add test to selftests (Alexei Starovoitov)
Signed-off-by: Dmitry Yakunin <zeil@yandex-team.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200620153052.9439-3-zeil@yandex-team.ru
Switch most of BPF helper definitions from returning int to long. These
definitions are coming from comments in BPF UAPI header and are used to
generate bpf_helper_defs.h (under libbpf) to be later included and used from
BPF programs.
In actual in-kernel implementation, all the helpers are defined as returning
u64, but due to some historical reasons, most of them are actually defined as
returning int in UAPI (usually, to return 0 on success, and negative value on
error).
This actually causes Clang to quite often generate sub-optimal code, because
compiler believes that return value is 32-bit, and in a lot of cases has to be
up-converted (usually with a pair of 32-bit bit shifts) to 64-bit values,
before they can be used further in BPF code.
Besides just "polluting" the code, these 32-bit shifts quite often cause
problems for cases in which return value matters. This is especially the case
for the family of bpf_probe_read_str() functions. There are few other similar
helpers (e.g., bpf_read_branch_records()), in which return value is used by
BPF program logic to record variable-length data and process it. For such
cases, BPF program logic carefully manages offsets within some array or map to
read variable-length data. For such uses, it's crucial for BPF verifier to
track possible range of register values to prove that all the accesses happen
within given memory bounds. Those extraneous zero-extending bit shifts,
inserted by Clang (and quite often interleaved with other code, which makes
the issues even more challenging and sometimes requires employing extra
per-variable compiler barriers), throws off verifier logic and makes it mark
registers as having unknown variable offset. We'll study this pattern a bit
later below.
Another common pattern is to check return of BPF helper for non-zero state to
detect error conditions and attempt alternative actions in such case. Even in
this simple and straightforward case, this 32-bit vs BPF's native 64-bit mode
quite often leads to sub-optimal and unnecessary extra code. We'll look at
this pattern as well.
Clang's BPF target supports two modes of code generation: ALU32, in which it
is capable of using lower 32-bit parts of registers, and no-ALU32, in which
only full 64-bit registers are being used. ALU32 mode somewhat mitigates the
above described problems, but not in all cases.
This patch switches all the cases in which BPF helpers return 0 or negative
error from returning int to returning long. It is shown below that such change
in definition leads to equivalent or better code. No-ALU32 mode benefits more,
but ALU32 mode doesn't degrade or still gets improved code generation.
Another class of cases switched from int to long are bpf_probe_read_str()-like
helpers, which encode successful case as non-negative values, while still
returning negative value for errors.
In all of such cases, correctness is preserved due to two's complement
encoding of negative values and the fact that all helpers return values with
32-bit absolute value. Two's complement ensures that for negative values
higher 32 bits are all ones and when truncated, leave valid negative 32-bit
value with the same value. Non-negative values have upper 32 bits set to zero
and similarly preserve value when high 32 bits are truncated. This means that
just casting to int/u32 is correct and efficient (and in ALU32 mode doesn't
require any extra shifts).
To minimize the chances of regressions, two code patterns were investigated,
as mentioned above. For both patterns, BPF assembly was analyzed in
ALU32/NO-ALU32 compiler modes, both with current 32-bit int return type and
new 64-bit long return type.
Case 1. Variable-length data reading and concatenation. This is quite
ubiquitous pattern in tracing/monitoring applications, reading data like
process's environment variables, file path, etc. In such case, many pieces of
string-like variable-length data are read into a single big buffer, and at the
end of the process, only a part of array containing actual data is sent to
user-space for further processing. This case is tested in test_varlen.c
selftest (in the next patch). Code flow is roughly as follows:
void *payload = &sample->payload;
u64 len;
len = bpf_probe_read_kernel_str(payload, MAX_SZ1, &source_data1);
if (len <= MAX_SZ1) {
payload += len;
sample->len1 = len;
}
len = bpf_probe_read_kernel_str(payload, MAX_SZ2, &source_data2);
if (len <= MAX_SZ2) {
payload += len;
sample->len2 = len;
}
/* and so on */
sample->total_len = payload - &sample->payload;
/* send over, e.g., perf buffer */
There could be two variations with slightly different code generated: when len
is 64-bit integer and when it is 32-bit integer. Both variations were analysed.
BPF assembly instructions between two successive invocations of
bpf_probe_read_kernel_str() were used to check code regressions. Results are
below, followed by short analysis. Left side is using helpers with int return
type, the right one is after the switch to long.
ALU32 + INT ALU32 + LONG
=========== ============
64-BIT (13 insns): 64-BIT (10 insns):
------------------------------------ ------------------------------------
17: call 115 17: call 115
18: if w0 > 256 goto +9 <LBB0_4> 18: if r0 > 256 goto +6 <LBB0_4>
19: w1 = w0 19: r1 = 0 ll
20: r1 <<= 32 21: *(u64 *)(r1 + 0) = r0
21: r1 s>>= 32 22: r6 = 0 ll
22: r2 = 0 ll 24: r6 += r0
24: *(u64 *)(r2 + 0) = r1 00000000000000c8 <LBB0_4>:
25: r6 = 0 ll 25: r1 = r6
27: r6 += r1 26: w2 = 256
00000000000000e0 <LBB0_4>: 27: r3 = 0 ll
28: r1 = r6 29: call 115
29: w2 = 256
30: r3 = 0 ll
32: call 115
32-BIT (11 insns): 32-BIT (12 insns):
------------------------------------ ------------------------------------
17: call 115 17: call 115
18: if w0 > 256 goto +7 <LBB1_4> 18: if w0 > 256 goto +8 <LBB1_4>
19: r1 = 0 ll 19: r1 = 0 ll
21: *(u32 *)(r1 + 0) = r0 21: *(u32 *)(r1 + 0) = r0
22: w1 = w0 22: r0 <<= 32
23: r6 = 0 ll 23: r0 >>= 32
25: r6 += r1 24: r6 = 0 ll
00000000000000d0 <LBB1_4>: 26: r6 += r0
26: r1 = r6 00000000000000d8 <LBB1_4>:
27: w2 = 256 27: r1 = r6
28: r3 = 0 ll 28: w2 = 256
30: call 115 29: r3 = 0 ll
31: call 115
In ALU32 mode, the variant using 64-bit length variable clearly wins and
avoids unnecessary zero-extension bit shifts. In practice, this is even more
important and good, because BPF code won't need to do extra checks to "prove"
that payload/len are within good bounds.
32-bit len is one instruction longer. Clang decided to do 64-to-32 casting
with two bit shifts, instead of equivalent `w1 = w0` assignment. The former
uses extra register. The latter might potentially lose some range information,
but not for 32-bit value. So in this case, verifier infers that r0 is [0, 256]
after check at 18:, and shifting 32 bits left/right keeps that range intact.
We should probably look into Clang's logic and see why it chooses bitshifts
over sub-register assignments for this.
NO-ALU32 + INT NO-ALU32 + LONG
============== ===============
64-BIT (14 insns): 64-BIT (10 insns):
------------------------------------ ------------------------------------
17: call 115 17: call 115
18: r0 <<= 32 18: if r0 > 256 goto +6 <LBB0_4>
19: r1 = r0 19: r1 = 0 ll
20: r1 >>= 32 21: *(u64 *)(r1 + 0) = r0
21: if r1 > 256 goto +7 <LBB0_4> 22: r6 = 0 ll
22: r0 s>>= 32 24: r6 += r0
23: r1 = 0 ll 00000000000000c8 <LBB0_4>:
25: *(u64 *)(r1 + 0) = r0 25: r1 = r6
26: r6 = 0 ll 26: r2 = 256
28: r6 += r0 27: r3 = 0 ll
00000000000000e8 <LBB0_4>: 29: call 115
29: r1 = r6
30: r2 = 256
31: r3 = 0 ll
33: call 115
32-BIT (13 insns): 32-BIT (13 insns):
------------------------------------ ------------------------------------
17: call 115 17: call 115
18: r1 = r0 18: r1 = r0
19: r1 <<= 32 19: r1 <<= 32
20: r1 >>= 32 20: r1 >>= 32
21: if r1 > 256 goto +6 <LBB1_4> 21: if r1 > 256 goto +6 <LBB1_4>
22: r2 = 0 ll 22: r2 = 0 ll
24: *(u32 *)(r2 + 0) = r0 24: *(u32 *)(r2 + 0) = r0
25: r6 = 0 ll 25: r6 = 0 ll
27: r6 += r1 27: r6 += r1
00000000000000e0 <LBB1_4>: 00000000000000e0 <LBB1_4>:
28: r1 = r6 28: r1 = r6
29: r2 = 256 29: r2 = 256
30: r3 = 0 ll 30: r3 = 0 ll
32: call 115 32: call 115
In NO-ALU32 mode, for the case of 64-bit len variable, Clang generates much
superior code, as expected, eliminating unnecessary bit shifts. For 32-bit
len, code is identical.
So overall, only ALU-32 32-bit len case is more-or-less equivalent and the
difference stems from internal Clang decision, rather than compiler lacking
enough information about types.
Case 2. Let's look at the simpler case of checking return result of BPF helper
for errors. The code is very simple:
long bla;
if (bpf_probe_read_kenerl(&bla, sizeof(bla), 0))
return 1;
else
return 0;
ALU32 + CHECK (9 insns) ALU32 + CHECK (9 insns)
==================================== ====================================
0: r1 = r10 0: r1 = r10
1: r1 += -8 1: r1 += -8
2: w2 = 8 2: w2 = 8
3: r3 = 0 3: r3 = 0
4: call 113 4: call 113
5: w1 = w0 5: r1 = r0
6: w0 = 1 6: w0 = 1
7: if w1 != 0 goto +1 <LBB2_2> 7: if r1 != 0 goto +1 <LBB2_2>
8: w0 = 0 8: w0 = 0
0000000000000048 <LBB2_2>: 0000000000000048 <LBB2_2>:
9: exit 9: exit
Almost identical code, the only difference is the use of full register
assignment (r1 = r0) vs half-registers (w1 = w0) in instruction #5. On 32-bit
architectures, new BPF assembly might be slightly less optimal, in theory. But
one can argue that's not a big issue, given that use of full registers is
still prevalent (e.g., for parameter passing).
NO-ALU32 + CHECK (11 insns) NO-ALU32 + CHECK (9 insns)
==================================== ====================================
0: r1 = r10 0: r1 = r10
1: r1 += -8 1: r1 += -8
2: r2 = 8 2: r2 = 8
3: r3 = 0 3: r3 = 0
4: call 113 4: call 113
5: r1 = r0 5: r1 = r0
6: r1 <<= 32 6: r0 = 1
7: r1 >>= 32 7: if r1 != 0 goto +1 <LBB2_2>
8: r0 = 1 8: r0 = 0
9: if r1 != 0 goto +1 <LBB2_2> 0000000000000048 <LBB2_2>:
10: r0 = 0 9: exit
0000000000000058 <LBB2_2>:
11: exit
NO-ALU32 is a clear improvement, getting rid of unnecessary zero-extension bit
shifts.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200623032224.4020118-1-andriin@fb.com
We keep getting more and more questions about BPF/libbpf usage.
This repo is not the right place to ask them, as not that many people
monitor it. Re-route folks to bpf@vger.kernel.org
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Add support for another (in addition to existing Kconfig) special kind of
externs in BPF code, kernel symbol externs. Such externs allow BPF code to
"know" kernel symbol address and either use it for comparisons with kernel
data structures (e.g., struct file's f_op pointer, to distinguish different
kinds of file), or, with the help of bpf_probe_user_kernel(), to follow
pointers and read data from global variables. Kernel symbol addresses are
found through /proc/kallsyms, which should be present in the system.
Currently, such kernel symbol variables are typeless: they have to be defined
as `extern const void <symbol>` and the only operation you can do (in C code)
with them is to take its address. Such extern should reside in a special
section '.ksyms'. bpf_helpers.h header provides __ksym macro for this. Strong
vs weak semantics stays the same as with Kconfig externs. If symbol is not
found in /proc/kallsyms, this will be a failure for strong (non-weak) extern,
but will be defaulted to 0 for weak externs.
If the same symbol is defined multiple times in /proc/kallsyms, then it will
be error if any of the associated addresses differs. In that case, address is
ambiguous, so libbpf falls on the side of caution, rather than confusing user
with randomly chosen address.
In the future, once kernel is extended with variables BTF information, such
ksym externs will be supported in a typed version, which will allow BPF
program to read variable's contents directly, similarly to how it's done for
fentry/fexit input arguments.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20200619231703.738941-3-andriin@fb.com
Add a bunch of getter for various aspects of BPF map. Some of these attribute
(e.g., key_size, value_size, type, etc) are available right now in struct
bpf_map_def, but this patch adds getter allowing to fetch them individually.
bpf_map_def approach isn't very scalable, when ABI stability requirements are
taken into account. It's much easier to extend libbpf and add support for new
features, when each aspect of BPF map has separate getter/setter.
Getters follow the common naming convention of not explicitly having "get" in
its name: bpf_map__type() returns map type, bpf_map__key_size() returns
key_size. Setters, though, explicitly have set in their name:
bpf_map__set_type(), bpf_map__set_key_size().
This patch ensures we now have a getter and a setter for the following
map attributes:
- type;
- max_entries;
- map_flags;
- numa_node;
- key_size;
- value_size;
- ifindex.
bpf_map__resize() enforces unnecessary restriction of max_entries > 0. It is
unnecessary, because libbpf actually supports zero max_entries for some cases
(e.g., for PERF_EVENT_ARRAY map) and treats it specially during map creation
time. To allow setting max_entries=0, new bpf_map__set_max_entries() setter is
added. bpf_map__resize()'s behavior is preserved for backwards compatibility
reasons.
Map ifindex getter is added as well. There is a setter already, but no
corresponding getter. Fix this assymetry as well. bpf_map__set_ifindex()
itself is converted from void function into error-returning one, similar to
other setters. The only error returned right now is -EBUSY, if BPF map is
already loaded and has corresponding FD.
One lacking attribute with no ability to get/set or even specify it
declaratively is numa_node. This patch fixes this gap and both adds
programmatic getter/setter, as well as adds support for numa_node field in
BTF-defined map.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200621062112.3006313-1-andriin@fb.com
Permanently blacklist load_bytes_relative test on 5.5 due to missing
functionality.
Also temporarily blacklist core_reloc test due to failure on latest kernel.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Fix definition of bpf_ringbuf_output() in UAPI header comments, which is used
to generate libbpf's bpf_helper_defs.h header. Return value is a number (error
code), not a pointer.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200615214926.3638836-1-andriin@fb.com
Remove invalid assumption in libbpf that .bss map doesn't have to be updated
in kernel. With addition of skeleton and memory-mapped initialization image,
.bss doesn't have to be all zeroes when BPF map is created, because user-code
might have initialized those variables from user-space.
Fixes: eba9c5f498a1 ("libbpf: Refactor global data map initialization")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200612194504.557844-1-andriin@fb.com
Initial versions of sync script couldn't handle non-empty merges. But since
then, script became smarter, more interactive and thus more powerful and can
handle some complicated situations easily on its own, while falling back to
human intervention for even more complicated situations. This non-empty merge
check has outlived its purpose and is just an annoying bump in sync process.
Drop it.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Handle a GCC quirk of emitting extra volatile modifier in DWARF (and
subsequently preserved in BTF by pahole) for function pointers marked as
__attribute__((noreturn)). This was the way to mark such functions before GCC
2.5 added noreturn attribute. Drop such func_proto modifiers, similarly to how
it's done for array (also to handle GCC quirk/bug).
Such volatile attribute is emitted by GCC only, so existing selftests can't
express such test. Simple repro is like this (compiled with GCC + BTF
generated by pahole):
struct my_struct {
void __attribute__((noreturn)) (*fn)(int);
};
struct my_struct a;
Without this fix, output will be:
struct my_struct {
voidvolatile (*fn)(int);
};
With the fix:
struct my_struct {
void (*fn)(int);
};
Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/bpf/20200610052335.2862559-1-andriin@fb.com
Add a bpf_csum_level() helper which BPF programs can use in combination
with bpf_skb_adjust_room() when they pass in BPF_F_ADJ_ROOM_NO_CSUM_RESET
flag to the latter to avoid falling back to CHECKSUM_NONE.
The bpf_csum_level() allows to adjust CHECKSUM_UNNECESSARY skb->csum_levels
via BPF_CSUM_LEVEL_{INC,DEC} which calls __skb_{incr,decr}_checksum_unnecessary()
on the skb. The helper also allows a BPF_CSUM_LEVEL_RESET which sets the skb's
csum to CHECKSUM_NONE as well as a BPF_CSUM_LEVEL_QUERY to just return the
current level. Without this helper, there is no way to otherwise adjust the
skb->csum_level. I did not add an extra dummy flags as there is plenty of free
bitspace in level argument itself iff ever needed in future.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/279ae3717cb3d03c0ffeb511493c93c450a01e1a.1591108731.git.daniel@iogearbox.net
Lorenz recently reported:
In our TC classifier cls_redirect [0], we use the following sequence of
helper calls to decapsulate a GUE (basically IP + UDP + custom header)
encapsulated packet:
bpf_skb_adjust_room(skb, -encap_len, BPF_ADJ_ROOM_MAC, BPF_F_ADJ_ROOM_FIXED_GSO)
bpf_redirect(skb->ifindex, BPF_F_INGRESS)
It seems like some checksums of the inner headers are not validated in
this case. For example, a TCP SYN packet with invalid TCP checksum is
still accepted by the network stack and elicits a SYN ACK. [...]
That is, we receive the following packet from the driver:
| ETH | IP | UDP | GUE | IP | TCP |
skb->ip_summed == CHECKSUM_UNNECESSARY
ip_summed is CHECKSUM_UNNECESSARY because our NICs do rx checksum offloading.
On this packet we run skb_adjust_room_mac(-encap_len), and get the following:
| ETH | IP | TCP |
skb->ip_summed == CHECKSUM_UNNECESSARY
Note that ip_summed is still CHECKSUM_UNNECESSARY. After bpf_redirect()'ing
into the ingress, we end up in tcp_v4_rcv(). There, skb_checksum_init() is
turned into a no-op due to CHECKSUM_UNNECESSARY.
The bpf_skb_adjust_room() helper is not aware of protocol specifics. Internally,
it handles the CHECKSUM_COMPLETE case via skb_postpull_rcsum(), but that does
not cover CHECKSUM_UNNECESSARY. In this case skb->csum_level of the original
skb prior to bpf_skb_adjust_room() call was 0, that is, covering UDP. Right now
there is no way to adjust the skb->csum_level. NICs that have checksum offload
disabled (CHECKSUM_NONE) or that support CHECKSUM_COMPLETE are not affected.
Use a safe default for CHECKSUM_UNNECESSARY by resetting to CHECKSUM_NONE and
add a flag to the helper called BPF_F_ADJ_ROOM_NO_CSUM_RESET that allows users
from opting out. Opting out is useful for the case where we don't remove/add
full protocol headers, or for the case where a user wants to adjust the csum
level manually e.g. through bpf_csum_level() helper that is added in subsequent
patch.
The bpf_skb_proto_{4_to_6,6_to_4}() for NAT64/46 translation from the BPF
bpf_skb_change_proto() helper uses bpf_skb_net_hdr_{push,pop}() pair internally
as well but doesn't change layers, only transitions between v4 to v6 and vice
versa, therefore no adoption is required there.
[0] https://lore.kernel.org/bpf/20200424185556.7358-1-lmb@cloudflare.com/
Fixes: 2be7e212d541 ("bpf: add bpf_skb_adjust_room helper")
Reported-by: Lorenz Bauer <lmb@cloudflare.com>
Reported-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/CACAyw9-uU_52esMd1JjuA80fRPHJv5vsSg8GnfW3t_qDU4aVKQ@mail.gmail.com/
Link: https://lore.kernel.org/bpf/11a90472e7cce83e76ddbfce81fdfce7bfc68808.1591108731.git.daniel@iogearbox.net
Extend bpf() syscall subcommands that operate on bpf_link, that is
LINK_CREATE, LINK_UPDATE, OBJ_GET_INFO, to accept attach types tied to
network namespaces (only flow dissector at the moment).
Link-based and prog-based attachment can be used interchangeably, but only
one can exist at a time. Attempts to attach a link when a prog is already
attached directly, and the other way around, will be met with -EEXIST.
Attempts to detach a program when link exists result in -EINVAL.
Attachment of multiple links of same attach type to one netns is not
supported with the intention to lift the restriction when a use-case
presents itself. Because of that link create returns -E2BIG when trying to
create another netns link, when one already exists.
Link-based attachments to netns don't keep a netns alive by holding a ref
to it. Instead links get auto-detached from netns when the latter is being
destroyed, using a pernet pre_exit callback.
When auto-detached, link lives in defunct state as long there are open FDs
for it. -ENOLINK is returned if a user tries to update a defunct link.
Because bpf_link to netns doesn't hold a ref to struct net, special care is
taken when releasing, updating, or filling link info. The netns might be
getting torn down when any of these link operations are in progress. That
is why auto-detach and update/release/fill_info are synchronized by the
same mutex. Also, link ops have to always check if auto-detach has not
happened yet and if netns is still alive (refcnt > 0).
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-5-jakub@cloudflare.com
Add xdp_txq_info as the Tx counterpart to xdp_rxq_info. At the
moment only the device is added. Other fields (queue_index)
can be added as use cases arise.
>From a UAPI perspective, add egress_ifindex to xdp context for
bpf programs to see the Tx device.
Update the verifier to only allow accesses to egress_ifindex by
XDP programs with BPF_XDP_DEVMAP expected attach type.
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-4-dsahern@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add BPF_XDP_DEVMAP attach type for use with programs associated with a
DEVMAP entry.
Allow DEVMAPs to associate a program with a device entry by adding
a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program
id, so the fd and id are a union. bpf programs can get access to the
struct via vmlinux.h.
The program associated with the fd must have type XDP with expected
attach type BPF_XDP_DEVMAP. When a program is associated with a device
index, the program is run on an XDP_REDIRECT and before the buffer is
added to the per-cpu queue. At this point rxq data is still valid; the
next patch adds tx device information allowing the prorgam to see both
ingress and egress device indices.
XDP generic is skb based and XDP programs do not work with skb's. Block
the use case by walking maps used by a program that is to be attached
via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with
Block attach of BPF_XDP_DEVMAP programs to devices.
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-3-dsahern@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Declaring and instantiating BPF ring buffer doesn't require any changes to
libbpf, as it's just another type of maps. So using existing BTF-defined maps
syntax with __uint(type, BPF_MAP_TYPE_RINGBUF) and __uint(max_elements,
<size-of-ring-buf>) is all that's necessary to create and use BPF ring buffer.
This patch adds BPF ring buffer consumer to libbpf. It is very similar to
perf_buffer implementation in terms of API, but also attempts to fix some
minor problems and inconveniences with existing perf_buffer API.
ring_buffer support both single ring buffer use case (with just using
ring_buffer__new()), as well as allows to add more ring buffers, each with its
own callback and context. This allows to efficiently poll and consume
multiple, potentially completely independent, ring buffers, using single
epoll instance.
The latter is actually a problem in practice for applications
that are using multiple sets of perf buffers. They have to create multiple
instances for struct perf_buffer and poll them independently or in a loop,
each approach having its own problems (e.g., inability to use a common poll
timeout). struct ring_buffer eliminates this problem by aggregating many
independent ring buffer instances under the single "ring buffer manager".
Second, perf_buffer's callback can't return error, so applications that need
to stop polling due to error in data or data signalling the end, have to use
extra mechanisms to signal that polling has to stop. ring_buffer's callback
can return error, which will be passed through back to user code and can be
acted upon appropariately.
Two APIs allow to consume ring buffer data:
- ring_buffer__poll(), which will wait for data availability notification
and will consume data only from reported ring buffer(s); this API allows
to efficiently use resources by reading data only when it becomes
available;
- ring_buffer__consume(), will attempt to read new records regardless of
data availablity notification sub-system. This API is useful for cases
when lowest latency is required, in expense of burning CPU resources.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200529075424.3139988-3-andriin@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit adds a new MPSC ring buffer implementation into BPF ecosystem,
which allows multiple CPUs to submit data to a single shared ring buffer. On
the consumption side, only single consumer is assumed.
Motivation
----------
There are two distinctive motivators for this work, which are not satisfied by
existing perf buffer, which prompted creation of a new ring buffer
implementation.
- more efficient memory utilization by sharing ring buffer across CPUs;
- preserving ordering of events that happen sequentially in time, even
across multiple CPUs (e.g., fork/exec/exit events for a task).
These two problems are independent, but perf buffer fails to satisfy both.
Both are a result of a choice to have per-CPU perf ring buffer. Both can be
also solved by having an MPSC implementation of ring buffer. The ordering
problem could technically be solved for perf buffer with some in-kernel
counting, but given the first one requires an MPSC buffer, the same solution
would solve the second problem automatically.
Semantics and APIs
------------------
Single ring buffer is presented to BPF programs as an instance of BPF map of
type BPF_MAP_TYPE_RINGBUF. Two other alternatives considered, but ultimately
rejected.
One way would be to, similar to BPF_MAP_TYPE_PERF_EVENT_ARRAY, make
BPF_MAP_TYPE_RINGBUF could represent an array of ring buffers, but not enforce
"same CPU only" rule. This would be more familiar interface compatible with
existing perf buffer use in BPF, but would fail if application needed more
advanced logic to lookup ring buffer by arbitrary key. HASH_OF_MAPS addresses
this with current approach. Additionally, given the performance of BPF
ringbuf, many use cases would just opt into a simple single ring buffer shared
among all CPUs, for which current approach would be an overkill.
Another approach could introduce a new concept, alongside BPF map, to
represent generic "container" object, which doesn't necessarily have key/value
interface with lookup/update/delete operations. This approach would add a lot
of extra infrastructure that has to be built for observability and verifier
support. It would also add another concept that BPF developers would have to
familiarize themselves with, new syntax in libbpf, etc. But then would really
provide no additional benefits over the approach of using a map.
BPF_MAP_TYPE_RINGBUF doesn't support lookup/update/delete operations, but so
doesn't few other map types (e.g., queue and stack; array doesn't support
delete, etc).
The approach chosen has an advantage of re-using existing BPF map
infrastructure (introspection APIs in kernel, libbpf support, etc), being
familiar concept (no need to teach users a new type of object in BPF program),
and utilizing existing tooling (bpftool). For common scenario of using
a single ring buffer for all CPUs, it's as simple and straightforward, as
would be with a dedicated "container" object. On the other hand, by being
a map, it can be combined with ARRAY_OF_MAPS and HASH_OF_MAPS map-in-maps to
implement a wide variety of topologies, from one ring buffer for each CPU
(e.g., as a replacement for perf buffer use cases), to a complicated
application hashing/sharding of ring buffers (e.g., having a small pool of
ring buffers with hashed task's tgid being a look up key to preserve order,
but reduce contention).
Key and value sizes are enforced to be zero. max_entries is used to specify
the size of ring buffer and has to be a power of 2 value.
There are a bunch of similarities between perf buffer
(BPF_MAP_TYPE_PERF_EVENT_ARRAY) and new BPF ring buffer semantics:
- variable-length records;
- if there is no more space left in ring buffer, reservation fails, no
blocking;
- memory-mappable data area for user-space applications for ease of
consumption and high performance;
- epoll notifications for new incoming data;
- but still the ability to do busy polling for new data to achieve the
lowest latency, if necessary.
BPF ringbuf provides two sets of APIs to BPF programs:
- bpf_ringbuf_output() allows to *copy* data from one place to a ring
buffer, similarly to bpf_perf_event_output();
- bpf_ringbuf_reserve()/bpf_ringbuf_commit()/bpf_ringbuf_discard() APIs
split the whole process into two steps. First, a fixed amount of space is
reserved. If successful, a pointer to a data inside ring buffer data area
is returned, which BPF programs can use similarly to a data inside
array/hash maps. Once ready, this piece of memory is either committed or
discarded. Discard is similar to commit, but makes consumer ignore the
record.
bpf_ringbuf_output() has disadvantage of incurring extra memory copy, because
record has to be prepared in some other place first. But it allows to submit
records of the length that's not known to verifier beforehand. It also closely
matches bpf_perf_event_output(), so will simplify migration significantly.
bpf_ringbuf_reserve() avoids the extra copy of memory by providing a memory
pointer directly to ring buffer memory. In a lot of cases records are larger
than BPF stack space allows, so many programs have use extra per-CPU array as
a temporary heap for preparing sample. bpf_ringbuf_reserve() avoid this needs
completely. But in exchange, it only allows a known constant size of memory to
be reserved, such that verifier can verify that BPF program can't access
memory outside its reserved record space. bpf_ringbuf_output(), while slightly
slower due to extra memory copy, covers some use cases that are not suitable
for bpf_ringbuf_reserve().
The difference between commit and discard is very small. Discard just marks
a record as discarded, and such records are supposed to be ignored by consumer
code. Discard is useful for some advanced use-cases, such as ensuring
all-or-nothing multi-record submission, or emulating temporary malloc()/free()
within single BPF program invocation.
Each reserved record is tracked by verifier through existing
reference-tracking logic, similar to socket ref-tracking. It is thus
impossible to reserve a record, but forget to submit (or discard) it.
bpf_ringbuf_query() helper allows to query various properties of ring buffer.
Currently 4 are supported:
- BPF_RB_AVAIL_DATA returns amount of unconsumed data in ring buffer;
- BPF_RB_RING_SIZE returns the size of ring buffer;
- BPF_RB_CONS_POS/BPF_RB_PROD_POS returns current logical possition of
consumer/producer, respectively.
Returned values are momentarily snapshots of ring buffer state and could be
off by the time helper returns, so this should be used only for
debugging/reporting reasons or for implementing various heuristics, that take
into account highly-changeable nature of some of those characteristics.
One such heuristic might involve more fine-grained control over poll/epoll
notifications about new data availability in ring buffer. Together with
BPF_RB_NO_WAKEUP/BPF_RB_FORCE_WAKEUP flags for output/commit/discard helpers,
it allows BPF program a high degree of control and, e.g., more efficient
batched notifications. Default self-balancing strategy, though, should be
adequate for most applications and will work reliable and efficiently already.
Design and implementation
-------------------------
This reserve/commit schema allows a natural way for multiple producers, either
on different CPUs or even on the same CPU/in the same BPF program, to reserve
independent records and work with them without blocking other producers. This
means that if BPF program was interruped by another BPF program sharing the
same ring buffer, they will both get a record reserved (provided there is
enough space left) and can work with it and submit it independently. This
applies to NMI context as well, except that due to using a spinlock during
reservation, in NMI context, bpf_ringbuf_reserve() might fail to get a lock,
in which case reservation will fail even if ring buffer is not full.
The ring buffer itself internally is implemented as a power-of-2 sized
circular buffer, with two logical and ever-increasing counters (which might
wrap around on 32-bit architectures, that's not a problem):
- consumer counter shows up to which logical position consumer consumed the
data;
- producer counter denotes amount of data reserved by all producers.
Each time a record is reserved, producer that "owns" the record will
successfully advance producer counter. At that point, data is still not yet
ready to be consumed, though. Each record has 8 byte header, which contains
the length of reserved record, as well as two extra bits: busy bit to denote
that record is still being worked on, and discard bit, which might be set at
commit time if record is discarded. In the latter case, consumer is supposed
to skip the record and move on to the next one. Record header also encodes
record's relative offset from the beginning of ring buffer data area (in
pages). This allows bpf_ringbuf_commit()/bpf_ringbuf_discard() to accept only
the pointer to the record itself, without requiring also the pointer to ring
buffer itself. Ring buffer memory location will be restored from record
metadata header. This significantly simplifies verifier, as well as improving
API usability.
Producer counter increments are serialized under spinlock, so there is
a strict ordering between reservations. Commits, on the other hand, are
completely lockless and independent. All records become available to consumer
in the order of reservations, but only after all previous records where
already committed. It is thus possible for slow producers to temporarily hold
off submitted records, that were reserved later.
Reservation/commit/consumer protocol is verified by litmus tests in
Documentation/litmus-test/bpf-rb.
One interesting implementation bit, that significantly simplifies (and thus
speeds up as well) implementation of both producers and consumers is how data
area is mapped twice contiguously back-to-back in the virtual memory. This
allows to not take any special measures for samples that have to wrap around
at the end of the circular buffer data area, because the next page after the
last data page would be first data page again, and thus the sample will still
appear completely contiguous in virtual memory. See comment and a simple ASCII
diagram showing this visually in bpf_ringbuf_area_alloc().
Another feature that distinguishes BPF ringbuf from perf ring buffer is
a self-pacing notifications of new data being availability.
bpf_ringbuf_commit() implementation will send a notification of new record
being available after commit only if consumer has already caught up right up
to the record being committed. If not, consumer still has to catch up and thus
will see new data anyways without needing an extra poll notification.
Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c) show that
this allows to achieve a very high throughput without having to resort to
tricks like "notify only every Nth sample", which are necessary with perf
buffer. For extreme cases, when BPF program wants more manual control of
notifications, commit/discard/output helpers accept BPF_RB_NO_WAKEUP and
BPF_RB_FORCE_WAKEUP flags, which give full control over notifications of data
availability, but require extra caution and diligence in using this API.
Comparison to alternatives
--------------------------
Before considering implementing BPF ring buffer from scratch existing
alternatives in kernel were evaluated, but didn't seem to meet the needs. They
largely fell into few categores:
- per-CPU buffers (perf, ftrace, etc), which don't satisfy two motivations
outlined above (ordering and memory consumption);
- linked list-based implementations; while some were multi-producer designs,
consuming these from user-space would be very complicated and most
probably not performant; memory-mapping contiguous piece of memory is
simpler and more performant for user-space consumers;
- io_uring is SPSC, but also requires fixed-sized elements. Naively turning
SPSC queue into MPSC w/ lock would have subpar performance compared to
locked reserve + lockless commit, as with BPF ring buffer. Fixed sized
elements would be too limiting for BPF programs, given existing BPF
programs heavily rely on variable-sized perf buffer already;
- specialized implementations (like a new printk ring buffer, [0]) with lots
of printk-specific limitations and implications, that didn't seem to fit
well for intended use with BPF programs.
[0] https://lwn.net/Articles/779550/
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200529075424.3139988-2-andriin@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This new API, perf_buffer__consume, can be used as follows:
- When you have a perf ring where wakeup_events is higher than 1,
and you have remaining data in the rings you would like to pull
out on exit (or maybe based on a timeout).
- For low latency cases where you burn a CPU that constantly polls
the queues.
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159048487929.89441.7465713173442594608.stgit@ebuild
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Disable a bunch of new kernel selftests that can't succeed on 5.5 kernel.
Flatten Travis tests into a single stage to parallelize and speed them up.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
As stated in 983695fa6765 ("bpf: fix unconnected udp hooks"), the objective
for the existing cgroup connect/sendmsg/recvmsg/bind BPF hooks is to be
transparent to applications. In Cilium we make use of these hooks [0] in
order to enable E-W load balancing for existing Kubernetes service types
for all Cilium managed nodes in the cluster. Those backends can be local
or remote. The main advantage of this approach is that it operates as close
as possible to the socket, and therefore allows to avoid packet-based NAT
given in connect/sendmsg/recvmsg hooks we only need to xlate sock addresses.
This also allows to expose NodePort services on loopback addresses in the
host namespace, for example. As another advantage, this also efficiently
blocks bind requests for applications in the host namespace for exposed
ports. However, one missing item is that we also need to perform reverse
xlation for inet{,6}_getname() hooks such that we can return the service
IP/port tuple back to the application instead of the remote peer address.
The vast majority of applications does not bother about getpeername(), but
in a few occasions we've seen breakage when validating the peer's address
since it returns unexpectedly the backend tuple instead of the service one.
Therefore, this trivial patch allows to customise and adds a getpeername()
as well as getsockname() BPF cgroup hook for both IPv4 and IPv6 in order
to address this situation.
Simple example:
# ./cilium/cilium service list
ID Frontend Service Type Backend
1 1.2.3.4:80 ClusterIP 1 => 10.0.0.10:80
Before; curl's verbose output example, no getpeername() reverse xlation:
# curl --verbose 1.2.3.4
* Rebuilt URL to: 1.2.3.4/
* Trying 1.2.3.4...
* TCP_NODELAY set
* Connected to 1.2.3.4 (10.0.0.10) port 80 (#0)
> GET / HTTP/1.1
> Host: 1.2.3.4
> User-Agent: curl/7.58.0
> Accept: */*
[...]
After; with getpeername() reverse xlation:
# curl --verbose 1.2.3.4
* Rebuilt URL to: 1.2.3.4/
* Trying 1.2.3.4...
* TCP_NODELAY set
* Connected to 1.2.3.4 (1.2.3.4) port 80 (#0)
> GET / HTTP/1.1
> Host: 1.2.3.4
> User-Agent: curl/7.58.0
> Accept: */*
[...]
Originally, I had both under a BPF_CGROUP_INET{4,6}_GETNAME type and exposed
peer to the context similar as in inet{,6}_getname() fashion, but API-wise
this is suboptimal as it always enforces programs having to test for ctx->peer
which can easily be missed, hence BPF_CGROUP_INET{4,6}_GET{PEER,SOCK}NAME split.
Similarly, the checked return code is on tnum_range(1, 1), but if a use case
comes up in future, it can easily be changed to return an error code instead.
Helper and ctx member access is the same as with connect/sendmsg/etc hooks.
[0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.c
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/61a479d759b2482ae3efb45546490bacd796a220.1589841594.git.daniel@iogearbox.net
Fixes the following warnings:
hashmap.c: In function ‘hashmap__clear’:
hashmap.h:150:20: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
150 | for (bkt = 0; bkt < map->cap; bkt++) \
hashmap.c: In function ‘hashmap_grow’:
hashmap.h:150:20: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
150 | for (bkt = 0; bkt < map->cap; bkt++) \
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200515165007.217120-4-irogers@google.com
With having ability to lookup sockets in cgroup skb programs it becomes
useful to access cgroup id of retrieved sockets so that policies can be
implemented based on origin cgroup of such socket.
For example, a container running in a cgroup can have cgroup skb ingress
program that can lookup peer socket that is sending packets to a process
inside the container and decide whether those packets should be allowed
or denied based on cgroup id of the peer.
More specifically such ingress program can implement intra-host policy
"allow incoming packets only from this same container and not from any
other container on same host" w/o relying on source IP addresses since
quite often it can be the case that containers share same IP address on
the host.
Introduce two new helpers for this use-case: bpf_sk_cgroup_id() and
bpf_sk_ancestor_cgroup_id().
These helpers are similar to existing bpf_skb_{,ancestor_}cgroup_id
helpers with the only difference that sk is used to get cgroup id
instead of skb, and share code with them.
See documentation in UAPI for more details.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/f5884981249ce911f63e9b57ecd5d7d19154ff39.1589486450.git.rdna@fb.com
bpf_sock_addr.user_port supports only 4-byte load and it leads to ugly
code in BPF programs, like:
volatile __u32 user_port = ctx->user_port;
__u16 port = bpf_ntohs(user_port);
Since otherwise clang may optimize the load to be 2-byte and it's
rejected by verifier.
Add support for 1- and 2-byte loads same way as it's supported for other
fields in bpf_sock_addr like user_ip4, msg_src_ip4, etc.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/c1e983f4c17573032601d0b2b1f9d1274f24bc16.1589420814.git.rdna@fb.com
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200507185057.GA13981@embeddedor
Two new libbpf APIs are added to support bpf_iter:
- bpf_program__attach_iter
Given a bpf program and additional parameters, which is
none now, returns a bpf_link.
- bpf_iter_create
syscall level API to create a bpf iterator.
The macro BPF_SEQ_PRINTF are also introduced. The format
looks like:
BPF_SEQ_PRINTF(seq, "task id %d\n", pid);
This macro can help bpf program writers with
nicer bpf_seq_printf syntax similar to the kernel one.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175917.2476936-1-yhs@fb.com
Two helpers bpf_seq_printf and bpf_seq_write, are added for
writing data to the seq_file buffer.
bpf_seq_printf supports common format string flag/width/type
fields so at least I can get identical results for
netlink and ipv6_route targets.
For bpf_seq_printf and bpf_seq_write, return value -EOVERFLOW
specifically indicates a write failure due to overflow, which
means the object will be repeated in the next bpf invocation
if object collection stays the same. Note that if the object
collection is changed, depending how collection traversal is
done, even if the object still in the collection, it may not
be visited.
For bpf_seq_printf, format %s, %p{i,I}{4,6} needs to
read kernel memory. Reading kernel memory may fail in
the following two cases:
- invalid kernel address, or
- valid kernel address but requiring a major fault
If reading kernel memory failed, the %s string will be
an empty string and %p{i,I}{4,6} will be all 0.
Not returning error to bpf program is consistent with
what bpf_trace_printk() does for now.
bpf_seq_printf may return -EBUSY meaning that internal percpu
buffer for memory copy of strings or other pointees is
not available. Bpf program can return 1 to indicate it
wants the same object to be repeated. Right now, this should not
happen on no-RT kernels since migrate_disable(), which guards
bpf prog call, calls preempt_disable().
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175914.2476661-1-yhs@fb.com
A new bpf command BPF_ITER_CREATE is added.
The anonymous bpf iterator is seq_file based.
The seq_file private data are referenced by targets.
The bpf_iter infrastructure allocated additional space
at seq_file->private before the space used by targets
to store some meta data, e.g.,
prog: prog to run
session_id: an unique id for each opened seq_file
seq_num: how many times bpf programs are queried in this session
done_stop: an internal state to decide whether bpf program
should be called in seq_ops->stop() or not
The seq_num will start from 0 for valid objects.
The bpf program may see the same seq_num more than once if
- seq_file buffer overflow happens and the same object
is retried by bpf_seq_read(), or
- the bpf program explicitly requests a retry of the
same object
Since module is not supported for bpf_iter, all target
registeration happens at __init time, so there is no
need to change bpf_iter_unreg_target() as it is used
mostly in error path of the init function at which time
no bpf iterators have been created yet.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175905.2475770-1-yhs@fb.com
Given a bpf program, the step to create an anonymous bpf iterator is:
- create a bpf_iter_link, which combines bpf program and the target.
In the future, there could be more information recorded in the link.
A link_fd will be returned to the user space.
- create an anonymous bpf iterator with the given link_fd.
The bpf_iter_link can be pinned to bpffs mount file system to
create a file based bpf iterator as well.
The benefit to use of bpf_iter_link:
- using bpf link simplifies design and implementation as bpf link
is used for other tracing bpf programs.
- for file based bpf iterator, bpf_iter_link provides a standard
way to replace underlying bpf programs.
- for both anonymous and free based iterators, bpf link query
capability can be leveraged.
The patch added support of tracing/iter programs for BPF_LINK_CREATE.
A new link type BPF_LINK_TYPE_ITER is added to facilitate link
querying. Currently, only prog_id is needed, so there is no
additional in-kernel show_fdinfo() and fill_link_info() hook
is needed for BPF_LINK_TYPE_ITER link.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175901.2475084-1-yhs@fb.com
A bpf_iter program is a tracing program with attach type
BPF_TRACE_ITER. The load attribute
attach_btf_id
is used by the verifier against a particular kernel function,
which represents a target, e.g., __bpf_iter__bpf_map
for target bpf_map which is implemented later.
The program return value must be 0 or 1 for now.
0 : successful, except potential seq_file buffer overflow
which is handled by seq_file reader.
1 : request to restart the same object
In the future, other return values may be used for filtering or
teminating the iterator.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175900.2474947-1-yhs@fb.com
We want to have a tighter control on what ports we bind to in
the BPF_CGROUP_INET{4,6}_CONNECT hooks even if it means
connect() becomes slightly more expensive. The expensive part
comes from the fact that we now need to call inet_csk_get_port()
that verifies that the port is not used and allocates an entry
in the hash table for it.
Since we can't rely on "snum || !bind_address_no_port" to prevent
us from calling POST_BIND hook anymore, let's add another bind flag
to indicate that the call site is BPF program.
v5:
* fix wrong AF_INET (should be AF_INET6) in the bpf program for v6
v3:
* More bpf_bind documentation refinements (Martin KaFai Lau)
* Add UDP tests as well (Martin KaFai Lau)
* Don't start the thread, just do socket+bind+listen (Martin KaFai Lau)
v2:
* Update documentation (Andrey Ignatov)
* Pass BIND_FORCE_ADDRESS_NO_PORT conditionally (Andrey Ignatov)
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-5-sdf@google.com
Currently, bpf_getsockopt and bpf_setsockopt helpers operate on the
'struct bpf_sock_ops' context in BPF_PROG_TYPE_SOCK_OPS program.
Let's generalize them and make them available for 'struct bpf_sock_addr'.
That way, in the future, we can allow those helpers in more places.
As an example, let's expose those 'struct bpf_sock_addr' based helpers to
BPF_CGROUP_INET{4,6}_CONNECT hooks. That way we can override CC before the
connection is made.
v3:
* Expose custom helpers for bpf_sock_addr context instead of doing
generic bpf_sock argument (as suggested by Daniel). Even with
try_socket_lock that doesn't sleep we have a problem where context sk
is already locked and socket lock is non-nestable.
v2:
* s/BPF_PROG_TYPE_CGROUP_SOCKOPT/BPF_PROG_TYPE_SOCK_OPS/
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200430233152.199403-1-sdf@google.com
Currently, sysctl kernel.bpf_stats_enabled controls BPF runtime stats.
Typical userspace tools use kernel.bpf_stats_enabled as follows:
1. Enable kernel.bpf_stats_enabled;
2. Check program run_time_ns;
3. Sleep for the monitoring period;
4. Check program run_time_ns again, calculate the difference;
5. Disable kernel.bpf_stats_enabled.
The problem with this approach is that only one userspace tool can toggle
this sysctl. If multiple tools toggle the sysctl at the same time, the
measurement may be inaccurate.
To fix this problem while keep backward compatibility, introduce a new
bpf command BPF_ENABLE_STATS. On success, this command enables stats and
returns a valid fd. BPF_ENABLE_STATS takes argument "type". Currently,
only one type, BPF_STATS_RUN_TIME, is supported. We can extend the
command to support other types of stats in the future.
With BPF_ENABLE_STATS, user space tool would have the following flow:
1. Get a fd with BPF_ENABLE_STATS, and make sure it is valid;
2. Check program run_time_ns;
3. Sleep for the monitoring period;
4. Check program run_time_ns again, calculate the difference;
5. Close the fd.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200430071506.1408910-2-songliubraving@fb.com
This patch adds a new port attribute, IFLA_BRPORT_MRP_RING_OPEN, which allows
to notify the userspace when the port lost the continuite of MRP frames.
This attribute is set by kernel whenever the SW or HW detects that the ring is
being open or closed.
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
bpf_obj_id selftest added testing of bpf_link related operations, which are
not implemented in 5.5.0. Blacklist it.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Fix memory leak in hashmap_clear() not freeing hashmap_entry structs for each
of the remaining entries. Also NULL-out bucket list to prevent possible
double-free between hashmap__clear() and hashmap__free().
Running test_progs-asan flavor clearly showed this problem.
Reported-by: Alston Tang <alston64@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429012111.277390-5-andriin@fb.com
As discussed at LPC 2019 ([0]), this patch brings (a quite belated) support
for declarative BTF-defined map-in-map support in libbpf. It allows to define
ARRAY_OF_MAPS and HASH_OF_MAPS BPF maps without any user-space initialization
code involved.
Additionally, it allows to initialize outer map's slots with references to
respective inner maps at load time, also completely declaratively.
Despite a weak type system of C, the way BTF-defined map-in-map definition
works, it's actually quite hard to accidentally initialize outer map with
incompatible inner maps. This being C, of course, it's still possible, but
even that would be caught at load time and error returned with helpful debug
log pointing exactly to the slot that failed to be initialized.
As an example, here's a rather advanced HASH_OF_MAPS declaration and
initialization example, filling slots #0 and #4 with two inner maps:
#include <bpf/bpf_helpers.h>
struct inner_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
} inner_map1 SEC(".maps"),
inner_map2 SEC(".maps");
struct outer_hash {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 5);
__uint(key_size, sizeof(int));
__array(values, struct inner_map);
} outer_hash SEC(".maps") = {
.values = {
[0] = &inner_map2,
[4] = &inner_map1,
},
};
Here's the relevant part of libbpf debug log showing pretty clearly of what's
going on with map-in-map initialization:
libbpf: .maps relo #0: for 6 value 0 rel.r_offset 96 name 260 ('inner_map1')
libbpf: .maps relo #0: map 'outer_arr' slot [0] points to map 'inner_map1'
libbpf: .maps relo #1: for 7 value 32 rel.r_offset 112 name 249 ('inner_map2')
libbpf: .maps relo #1: map 'outer_arr' slot [2] points to map 'inner_map2'
libbpf: .maps relo #2: for 7 value 32 rel.r_offset 144 name 249 ('inner_map2')
libbpf: .maps relo #2: map 'outer_hash' slot [0] points to map 'inner_map2'
libbpf: .maps relo #3: for 6 value 0 rel.r_offset 176 name 260 ('inner_map1')
libbpf: .maps relo #3: map 'outer_hash' slot [4] points to map 'inner_map1'
libbpf: map 'inner_map1': created successfully, fd=4
libbpf: map 'inner_map2': created successfully, fd=5
libbpf: map 'outer_hash': created successfully, fd=7
libbpf: map 'outer_hash': slot [0] set to map 'inner_map2' fd=5
libbpf: map 'outer_hash': slot [4] set to map 'inner_map1' fd=4
Notice from the log above that fd=6 (not logged explicitly) is used for inner
"prototype" map, necessary for creation of outer map. It is destroyed
immediately after outer map is created.
See also included selftest with some extra comments explaining extra details
of usage. Additionally, similar initialization syntax and libbpf functionality
can be used to do initialization of BPF_PROG_ARRAY with references to BPF
sub-programs. This can be done in follow up patches, if there will be a demand
for this.
[0] https://linuxplumbersconf.org/event/4/contributions/448/
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200429002739.48006-4-andriin@fb.com
Factor out map creation and destruction logic to simplify code and especially
error handling. Also fix map FD leak in case of partially successful map
creation during bpf_object load operation.
Fixes: 57a00f41644f ("libbpf: Add auto-pinning of maps when loading BPF objects")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200429002739.48006-3-andriin@fb.com
Add ability to fetch bpf_link details through BPF_OBJ_GET_INFO_BY_FD command.
Also enhance show_fdinfo to potentially include bpf_link type-specific
information (similarly to obj_info).
Also introduce enum bpf_link_type stored in bpf_link itself and expose it in
UAPI. bpf_link_tracing also now will store and return bpf_attach_type.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-5-andriin@fb.com
On a device like a cellphone which is constantly suspending
and resuming CLOCK_MONOTONIC is not particularly useful for
keeping track of or reacting to external network events.
Instead you want to use CLOCK_BOOTTIME.
Hence add bpf_ktime_get_boot_ns() as a mirror of bpf_ktime_get_ns()
based around CLOCK_BOOTTIME instead of CLOCK_MONOTONIC.
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The following error was shown when a bpf program was compiled without
vmlinux.h auto-generated from BTF:
# clang -I./linux/tools/lib/ -I/lib/modules/$(uname -r)/build/include/ \
-O2 -Wall -target bpf -emit-llvm -c bpf_prog.c -o bpf_prog.bc
...
In file included from linux/tools/lib/bpf/bpf_helpers.h:5:
linux/tools/lib/bpf/bpf_helper_defs.h:56:82: error: unknown type name '__u64'
...
It seems that bpf programs are intended for being built together with
the vmlinux.h (which will have all the __u64 and other typedefs). But
users may mistakenly think "include <linux/types.h>" is missing
because the vmlinux.h is not common for non-bpf developers. IMO, an
explicit comment therefore should be added to bpf_helpers.h as this
patch shows.
Signed-off-by: Yoshiki Komachi <komachi.yoshiki@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/1587427527-29399-1-git-send-email-komachi.yoshiki@gmail.com
The commit in the Fixes tag changed get_xdp_id to only return prog_id
if flags is 0, but there are other XDP flags than the modes - e.g.,
XDP_FLAGS_UPDATE_IF_NOEXIST. Since the intention was only to look at
MODE flags, clear other ones before checking if flags is 0.
Fixes: f07cbad29741 ("libbpf: Fix bpf_get_link_xdp_id flags handling")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrey Ignatov <rdna@fb.com>
Newer git started emitting warning about dangerousness of filter-branch.
Squelch it with FILTER_BRANCH_SQUELCH_WARNING=1 envvar.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
5.5 kernel has a bug in kernel allowing to violate read-only access to
mmap()-ed map. Disable selftest that now is failing.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
The 'old_fd' parameter used for atomic replacement of XDP programs is
supposed to be an FD, but was left as a u32 from an earlier iteration of
the patch that added it. It was converted to an int when read, so things
worked correctly even with negative values, but better change the
definition to correctly reflect the intention.
Fixes: bd5ca3ef93cd ("libbpf: Add function to set link XDP fd while specifying old program")
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200414145025.182163-1-toke@redhat.com
For some types of BPF programs that utilize expected_attach_type, libbpf won't
set load_attr.expected_attach_type, even if expected_attach_type is known from
section definition. This was done to preserve backwards compatibility with old
kernels that didn't recognize expected_attach_type attribute yet (which was
added in 5e43f899b03a ("bpf: Check attach type at prog load time"). But this
is problematic for some BPF programs that utilize newer features that require
kernel to know specific expected_attach_type (e.g., extended set of return
codes for cgroup_skb/egress programs).
This patch makes libbpf specify expected_attach_type by default, but also
detect support for this field in kernel and not set it during program load.
This allows to have a good metadata for bpf_program
(e.g., bpf_program__get_extected_attach_type()), but still work with old
kernels (for cases where it can work at all).
Additionally, due to expected_attach_type being always set for recognized
program types, bpf_program__attach_cgroup doesn't have to do extra checks to
determine correct attach type, so remove that additional logic.
Also adjust section_names selftest to account for this change.
More detailed discussion can be found in [0].
[0] https://lore.kernel.org/bpf/20200412003604.GA15986@rdna-mbp.dhcp.thefacebook.com/
Fixes: 5cf1e9145630 ("bpf: cgroup inet skb programs can return 0 to 3")
Fixes: 5e43f899b03a ("bpf: Check attach type at prog load time")
Reported-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20200414182645.1368174-1-andriin@fb.com
Currently if one of XDP_FLAGS_{DRV,HW,SKB}_MODE flags is passed to
bpf_get_link_xdp_id() and there is a single XDP program attached to
ifindex, that program's id will be returned by bpf_get_link_xdp_id() in
prog_id argument no matter what mode the program is attached in, i.e.
flags argument is not taken into account.
For example, if there is a single program attached with
XDP_FLAGS_SKB_MODE but user calls bpf_get_link_xdp_id() with flags =
XDP_FLAGS_DRV_MODE, that skb program will be returned.
Fix it by returning info->prog_id only if user didn't specify flags. If
flags is specified then return corresponding mode-specific-field from
struct xdp_link_info.
The initial error was introduced in commit 50db9f073188 ("libbpf: Add a
support for getting xdp prog id on ifindex") and then refactored in
473f4e133a12 so 473f4e133a12 is used in the Fixes tag.
Fixes: 473f4e133a12 ("libbpf: Add bpf_get_link_xdp_info() function to get more XDP information")
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/0e9e30490b44b447bb2bebc69c7135e7fe7e4e40.1586236080.git.rdna@fb.com
Builds of Fedora's kernel-tools package started to fail with "may be
used uninitialized" warnings for nl_pid in bpf_set_link_xdp_fd() and
bpf_get_link_xdp_info() on the s390 architecture.
Although libbpf_netlink_open() always returns a negative number when it
does not set *nl_pid, the compiler does not determine this and thus
believes the variable might be used uninitialized. Assuage gcc's fears
by explicitly initializing nl_pid.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1807781
Signed-off-by: Jeremy Cline <jcline@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200404051430.698058-1-jcline@redhat.com
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit: 483d7a30f538e2f8addd32aa9a3d2e94ae55fa65
Checkpoint bpf-next commit: 1a323ea5356edbb3073dc59d51b9e6b86908857d
Baseline bpf commit: 94b18a87efdd1626a1e6aef87271af4a7c616d36
Checkpoint bpf commit: 94b18a87efdd1626a1e6aef87271af4a7c616d36
Andrii Nakryiko (2):
bpf: Implement bpf_link-based cgroup BPF program attachment
libbpf: Add support for bpf_link-based cgroup attachment
Antoine Tenart (1):
net: macsec: add support for offloading to the MAC
Daniel Borkmann (2):
bpf: Add netns cookie and enable it for bpf cgroup hooks
bpf: Enable bpf cgroup hooks to retrieve cgroup v2 and ancestor id
Fletcher Dunn (1):
libbpf, xsk: Init all ring members in xsk_umem__create and
xsk_socket__create
Joe Stringer (1):
bpf: Add socket assign support
KP Singh (2):
bpf: Introduce BPF_PROG_TYPE_LSM
tools/libbpf: Add support for BPF_PROG_TYPE_LSM
Mark Starovoytov (1):
net: macsec: add support for specifying offload upon link creation
Stanislav Fomichev (1):
libbpf: Don't allocate 16M for log buffer by default
Tobias Klauser (1):
libbpf: Remove unused parameter `def` to get_map_field_int
Toke Høiland-Jørgensen (3):
tools: Add EXPECTED_FD-related definitions in if_link.h
libbpf: Add function to set link XDP fd while specifying old program
libbpf: Add setter for initial value for internal maps
include/uapi/linux/bpf.h | 82 ++++++++++++++++++++-
include/uapi/linux/if_link.h | 6 +-
src/bpf.c | 37 +++++++++-
src/bpf.h | 19 +++++
src/btf.c | 20 ++++--
src/libbpf.c | 134 +++++++++++++++++++++++++++++------
src/libbpf.h | 22 +++++-
src/libbpf.map | 9 +++
src/libbpf_probes.c | 1 +
src/netlink.c | 34 ++++++++-
src/xsk.c | 16 ++++-
11 files changed, 345 insertions(+), 35 deletions(-)
--
2.24.1
Add bpf_program__attach_cgroup(), which uses BPF_LINK_CREATE subcommand to
create an FD-based kernel bpf_link. Also add low-level bpf_link_create() API.
If expected_attach_type is not specified explicitly with
bpf_program__set_expected_attach_type(), libbpf will try to determine proper
attach type from BPF program's section definition.
Also add support for bpf_link's underlying BPF program replacement:
- unconditional through high-level bpf_link__update_program() API;
- cmpxchg-like with specifying expected current BPF program through
low-level bpf_link_update() API.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200330030001.2312810-4-andriin@fb.com
Implement new sub-command to attach cgroup BPF programs and return FD-based
bpf_link back on success. bpf_link, once attached to cgroup, cannot be
replaced, except by owner having its FD. Cgroup bpf_link supports only
BPF_F_ALLOW_MULTI semantics. Both link-based and prog-based BPF_F_ALLOW_MULTI
attachments can be freely intermixed.
To prevent bpf_cgroup_link from keeping cgroup alive past the point when no
BPF program can be executed, implement auto-detachment of link. When
cgroup_bpf_release() is called, all attached bpf_links are forced to release
cgroup refcounts, but they leave bpf_link otherwise active and allocated, as
well as still owning underlying bpf_prog. This is because user-space might
still have FDs open and active, so bpf_link as a user-referenced object can't
be freed yet. Once last active FD is closed, bpf_link will be freed and
underlying bpf_prog refcount will be dropped. But cgroup refcount won't be
touched, because cgroup is released already.
The inherent race between bpf_cgroup_link release (from closing last FD) and
cgroup_bpf_release() is resolved by both operations taking cgroup_mutex. So
the only additional check required is when bpf_cgroup_link attempts to detach
itself from cgroup. At that time we need to check whether there is still
cgroup associated with that link. And if not, exit with success, because
bpf_cgroup_link was already successfully detached.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Link: https://lore.kernel.org/bpf/20200330030001.2312810-2-andriin@fb.com
Add support for TPROXY via a new bpf helper, bpf_sk_assign().
This helper requires the BPF program to discover the socket via a call
to bpf_sk*_lookup_*(), then pass this socket to the new helper. The
helper takes its own reference to the socket in addition to any existing
reference that may or may not currently be obtained for the duration of
BPF processing. For the destination socket to receive the traffic, the
traffic must be routed towards that socket via local route. The
simplest example route is below, but in practice you may want to route
traffic more narrowly (eg by CIDR):
$ ip route add local default dev lo
This patch avoids trying to introduce an extra bit into the skb->sk, as
that would require more invasive changes to all code interacting with
the socket to ensure that the bit is handled correctly, such as all
error-handling cases along the path from the helper in BPF through to
the orphan path in the input. Instead, we opt to use the destructor
variable to switch on the prefetch of the socket.
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200329225342.16317-2-joe@wand.net.nz
For internal maps (most notably the maps backing global variables), libbpf
uses an internal mmaped area to store the data after opening the object.
This data is subsequently copied into the kernel map when the object is
loaded.
This adds a function to set a new value for that data, which can be used to
before it is loaded into the kernel. This is especially relevant for RODATA
maps, since those are frozen on load.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200329132253.232541-1-toke@redhat.com
Fix a sharp edge in xsk_umem__create and xsk_socket__create. Almost all of
the members of the ring buffer structs are initialized, but the "cached_xxx"
variables are not all initialized. The caller is required to zero them.
This is needlessly dangerous. The results if you don't do it can be very bad.
For example, they can cause xsk_prod_nb_free and xsk_cons_nb_avail to return
values greater than the size of the queue. xsk_ring_cons__peek can return an
index that does not refer to an item that has been queued.
I have confirmed that without this change, my program misbehaves unless I
memset the ring buffers to zero before calling the function. Afterwards,
my program works without (or with) the memset.
Signed-off-by: Fletcher Dunn <fletcherd@valvesoftware.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/85f12913cde94b19bfcb598344701c38@valvesoftware.com
Enable the bpf_get_current_cgroup_id() helper for connect(), sendmsg(),
recvmsg() and bind-related hooks in order to retrieve the cgroup v2
context which can then be used as part of the key for BPF map lookups,
for example. Given these hooks operate in process context 'current' is
always valid and pointing to the app that is performing mentioned
syscalls if it's subject to a v2 cgroup. Also with same motivation of
commit 7723628101aa ("bpf: Introduce bpf_skb_ancestor_cgroup_id helper")
enable retrieval of ancestor from current so the cgroup id can be used
for policy lookups which can then forbid connect() / bind(), for example.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/d2a7ef42530ad299e3cbb245e6c12374b72145ef.1585323121.git.daniel@iogearbox.net
In Cilium we're mainly using BPF cgroup hooks today in order to implement
kube-proxy free Kubernetes service translation for ClusterIP, NodePort (*),
ExternalIP, and LoadBalancer as well as HostPort mapping [0] for all traffic
between Cilium managed nodes. While this works in its current shape and avoids
packet-level NAT for inter Cilium managed node traffic, there is one major
limitation we're facing today, that is, lack of netns awareness.
In Kubernetes, the concept of Pods (which hold one or multiple containers)
has been built around network namespaces, so while we can use the global scope
of attaching to root BPF cgroup hooks also to our advantage (e.g. for exposing
NodePort ports on loopback addresses), we also have the need to differentiate
between initial network namespaces and non-initial one. For example, ExternalIP
services mandate that non-local service IPs are not to be translated from the
host (initial) network namespace as one example. Right now, we have an ugly
work-around in place where non-local service IPs for ExternalIP services are
not xlated from connect() and friends BPF hooks but instead via less efficient
packet-level NAT on the veth tc ingress hook for Pod traffic.
On top of determining whether we're in initial or non-initial network namespace
we also have a need for a socket-cookie like mechanism for network namespaces
scope. Socket cookies have the nice property that they can be combined as part
of the key structure e.g. for BPF LRU maps without having to worry that the
cookie could be recycled. We are planning to use this for our sessionAffinity
implementation for services. Therefore, add a new bpf_get_netns_cookie() helper
which would resolve both use cases at once: bpf_get_netns_cookie(NULL) would
provide the cookie for the initial network namespace while passing the context
instead of NULL would provide the cookie from the application's network namespace.
We're using a hole, so no size increase; the assignment happens only once.
Therefore this allows for a comparison on initial namespace as well as regular
cookie usage as we have today with socket cookies. We could later on enable
this helper for other program types as well as we would see need.
(*) Both externalTrafficPolicy={Local|Cluster} types
[0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.c
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/c47d2346982693a9cf9da0e12690453aded4c788.1585323121.git.daniel@iogearbox.net
For each prog/btf load we allocate and free 16 megs of verifier buffer.
On production systems it doesn't really make sense because the
programs/btf have gone through extensive testing and (mostly) guaranteed
to successfully load.
Let's assume successful case by default and skip buffer allocation
on the first try. If there is an error, start with BPF_LOG_BUF_SIZE
and double it on each ENOSPC iteration.
v3:
* Return -ENOMEM when can't allocate log buffer (Andrii Nakryiko)
v2:
* Don't allocate the buffer at all on the first try (Andrii Nakryiko)
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200325195521.112210-1-sdf@google.com
This patch adds new netlink attribute to allow a user to (optionally)
specify the desired offload mode immediately upon MACSec link creation.
Separate iproute patch will be required to support this from user space.
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a new MACsec offloading option, MACSEC_OFFLOAD_MAC,
allowing a user to select a MAC as a provider for MACsec offloading
operations.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Enable now-fixed sockmap_listen tests. Disabled vmlinux test on 5.5, on which
hrtimer_nanosleep() signature is incompatible. Filled out remaining
permanently disabled tests resons.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Syscall raw tracepoints have struct pt_regs pointer as tracepoint's first
argument. After that, reading any of pt_regs fields requires bpf_probe_read(),
even for tp_btf programs. Due to that, PT_REGS_PARMx macros are not usable as
is. This patch adds CO-RE variants of those macros that use BPF_CORE_READ() to
read necessary fields. This provides relocatable architecture-agnostic pt_regs
field accesses.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200313172336.1879637-4-andriin@fb.com
With fixes in selftests, these tests should now pass.
Also add ability to add comments to blacklist/whitelist to explain why certain
test is disabled.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Needs for application BTF being present differs between user-space libbpf needs and kernel
needs. Currently, BTF is mandatory only in kernel only when BPF application is
using STRUCT_OPS. While libbpf itself relies more heavily on presense of BTF:
- for BTF-defined maps;
- for Kconfig externs;
- for STRUCT_OPS as well.
Thus, checks for presence and validness of bpf_object's BPF needs to be
performed separately, which is patch does.
Fixes: 5327644614a1 ("libbpf: Relax check whether BTF is mandatory")
Reported-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Cc: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200312185033.736911-1-andriin@fb.com
When multiple programs are attached, each program receives the return
value from the previous program on the stack and the last program
provides the return value to the attached function.
The fmod_ret bpf programs are run after the fentry programs and before
the fexit programs. The original function is only called if all the
fmod_ret programs return 0 to avoid any unintended side-effects. The
success value, i.e. 0 is not currently configurable but can be made so
where user-space can specify it at load time.
For example:
int func_to_be_attached(int a, int b)
{ <--- do_fentry
do_fmod_ret:
<update ret by calling fmod_ret>
if (ret != 0)
goto do_fexit;
original_function:
<side_effects_happen_here>
} <--- do_fexit
The fmod_ret program attached to this function can be defined as:
SEC("fmod_ret/func_to_be_attached")
int BPF_PROG(func_name, int a, int b, int ret)
{
// This will skip the original function logic.
return 1;
}
The first fmod_ret program is passed 0 in its return argument.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200304191853.1529-4-kpsingh@chromium.org
Currently, BTF_KIND_ENUM type doesn't record whether enum values should be
interpreted as signed or unsigned. In Linux, most enums are unsigned, though,
so interpreting them as unsigned matches real world better.
Change btf_dump test case to test maximum 32-bit value, instead of negative
value.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200303003233.3496043-3-andriin@fb.com
Switch BPF UAPI constants, previously defined as #define macro, to anonymous
enum values. This preserves constants values and behavior in expressions, but
has added advantaged of being captured as part of DWARF and, subsequently, BTF
type info. Which, in turn, greatly improves usefulness of generated vmlinux.h
for BPF applications, as it will not require BPF users to copy/paste various
flags and constants, which are frequently used with BPF helpers. Only those
constants that are used/useful from BPF program side are converted.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200303003233.3496043-2-andriin@fb.com
Internal functions, used by btf_dump__emit_type_decl(), assume field_name is
never going to be NULL. Ensure it's always the case.
Fixes: 9f81654eebe8 ("libbpf: Expose BTF-to-C type declaration emitting API")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200303180800.3303471-1-andriin@fb.com
Generate a disk image for libbpf testing in compressed *.zst format
The mkrootfs.sh has the following stages:
- run pacstrap to install libbpf and selftests dependencies.
- create /etc/fstab w/ bpffs and debugfs filesystems
- create /etc/init.d/rcS to mount in bootime
- create /etc/inittab to invoke /etc/init.d/rcS
- compress an image
In addition ./travis-ci/vmtest/run.sh set up ext4 fs and mounts
it as a loop device:
mkfs.ext4 -q "$tmp"
mount -o loop "$tmp" "$mnt"
Signed-off-by: Julia Kartseva (hex@fb.com)
The disk image is updated to 2020-03-11.
blacklist for LATEST kernel:
attach_probe (needs root cause)
perf_buffer (needs root cause)
send_signal (flaky)
sockmap_listen (flaky)
Run test_maps and test_verifier.
test_maps is not expected to pass for kernels other then LATEST.
Signed-off-by: Julia Kartseva (hex@fb.com)
With bpf_link abstraction supported by kernel explicitly, add
pinning/unpinning API for links. Also allow to create (open) bpf_link from BPF
FS file.
This API allows to have an "ephemeral" FD-based BPF links (like raw tracepoint
or fexit/freplace attachments) surviving user process exit, by pinning them in
a BPF FS, which is an important use case for long-running BPF programs.
As part of this, expose underlying FD for bpf_link. While legacy bpf_link's
might not have a FD associated with them (which will be expressed as
a bpf_link with fd=-1), kernel's abstraction is based around FD-based usage,
so match it closely. This, subsequently, allows to have a generic
pinning/unpinning API for generalized bpf_link. For some types of bpf_links
kernel might not support pinning, in which case bpf_link__pin() will return
error.
With FD being part of generic bpf_link, also get rid of bpf_link_fd in favor
of using vanialla bpf_link.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200303043159.323675-3-andriin@fb.com
Add detection of vmlinux.h to bpf_tracing.h header for PT_REGS macro.
Currently, BPF applications have to define __KERNEL__ symbol to use correct
definition of struct pt_regs on x86 arch. This is due to different field names
under internal kernel vs UAPI conditions. To make this more transparent for
users, detect vmlinux.h by checking __VMLINUX_H__ symbol.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200229231112.1240137-3-andriin@fb.com
Set up loopback to enable more tests:
- bpf_tcp_ca
- cgroup_attach_autodetach
- cgroup_attach_multi
- cgroup_attach_override
- select_reuseport
- sockmap_ktls
Signed-off-by: Julia Kartseva hex@fb.com
Manually bump sync commit from kernel repo. There are no libbpf changes, but
we need latest selftest patches to try to debug more of crashing selftests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Currently when you want to attach a trace program to a bpf program
the section name needs to match the tracepoint/function semantics.
However the addition of the bpf_program__set_attach_target() API
allows you to specify the tracepoint/function dynamically.
The call flow would look something like this:
xdp_fd = bpf_prog_get_fd_by_id(id);
trace_obj = bpf_object__open_file("func.o", NULL);
prog = bpf_object__find_program_by_title(trace_obj,
"fentry/myfunc");
bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY);
bpf_program__set_attach_target(prog, xdp_fd,
"xdpfilt_blk_all");
bpf_object__load(trace_obj)
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158220519486.127661.7964708960649051384.stgit@xdp-tutorial
Build latest pahole from sources and not rely on hacky Ubuntu repository
approach.
Also enable tests for latest kernel that rely on pahole 1.16.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Clean up Travis CI config, extract multi-step initializations into scripts.
Also, move kernel-building tests to happen last to not block lightweight
Debian and Ubuntu tests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
The kernel only accepts map names with alphanumeric characters, underscores
and periods in their name. However, the auto-generated internal map names
used by libbpf takes their prefix from the user-supplied BPF object name,
which has no such restriction. This can lead to "Invalid argument" errors
when trying to load a BPF program using global variables.
Fix this by sanitising the map names, replacing any non-allowed characters
with underscores.
Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200217171701.215215-1-toke@redhat.com
The performance of bpf_redirect() is now roughly the same as that of
bpf_redirect_map(). However, David Ahern pointed out that the header file
has not been updated to reflect this, and still says that a significant
performance increase is possible when using bpf_redirect_map(). Remove this
text from the bpf_redirect_map() description, and reword the description in
bpf_redirect() slightly. Also fix the 'Return' section of the
bpf_redirect_map() documentation.
Fixes: 1d233886dd90 ("xdp: Use bulking for non-map XDP_REDIRECT and consolidate code paths")
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200218130334.29889-1-toke@redhat.com
If BPF program is using BTF-defined maps, BTF is required only for
libbpf itself to process map definitions. If after that BTF fails to
be loaded into kernel (e.g., if it doesn't support BTF at all), this
shouldn't prevent valid BPF program from loading. Existing
retry-without-BTF logic for creating maps will succeed to create such
maps without any problems. So, presence of .maps section shouldn't make
BTF required for kernel. Update the check accordingly.
Validated by ensuring simple BPF program with BTF-defined maps is still
loaded on old kernel without BTF support and map is correctly parsed and
created.
Fixes: abd29c931459 ("libbpf: allow specifying map definitions using BTF")
Reported-by: Julia Kartseva <hex@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200220062635.1497872-1-andriin@fb.com
Add a selftest to test:
* default bpf_read_branch_records() behavior
* BPF_F_GET_BRANCH_RECORDS_SIZE flag behavior
* error path on non branch record perf events
* using helper to write to stack
* using helper to write to global
On host with hardware counter support:
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
On host without hardware counter support (VM):
# ./test_progs -t perf_branches
#27/1 perf_branches_hw:OK
#27/2 perf_branches_no_hw:OK
#27 perf_branches:OK
Summary: 1/2 PASSED, 1 SKIPPED, 0 FAILED
Also sync tools/include/uapi/linux/bpf.h.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-3-dxu@dxuuu.xyz
Update blacklists to omit some of the newest selftests. Also ensure that
blacklist is sorted alphabetically.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Commit signature, used to determine already synced commits, includes a short
stats per each file relevant. Fix this script to include only files that are
actually synced (i.e., exclude Makefile, Build file, etc).
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
- The previously introduced git fetch depth of bpf-next tree is not sufficient
when bpf-next tree is far ahead from libbpf checkpoint commit, so increase the
depth up to 128 max. Since 128 may be an overkill for a general case, increase
exponentially in a loop until max is reached.
- Do not fetch bpf-next twice
- Remove setup_example.sh
Run kernel selftests in vmtest with the goal to test libbpf backward
compatibility with older kernels.
The list of kernels should be specified in .travis.yml config in
`jobs` section, e.g. KERNEL=5.5.0.
Enlisted kernel releases
- 5.5.0 # built from main
- 5.5.0-rc6 # built from bpf-next
- LATEST
The kernel specified as 'LATEST' in .travis.yml is built from bpf-next kernel
tree, the rest of the kernels are downloaded from the specified in INDEX file.
The kernel sources from bpf-next are manually patched with [1] from bpf tree to
fix ranqslower build. This workaround should be removed after the patch is merged
from bpf to bpf-next tree.
Due to kernel sources being checked out the duration of the LATEST kernel test is
~30m.
bpf selftests are built from tools/testing/selftests/bpf/ of bpf-next tree with
HEAD revision set to CHECKPOINT-COMMIT specified in libbpf so selftests and
libbpf are in sync.
Currently only programs are tested with test_progs program, test_maps and
test_verifier should follow.
test_progs are run with blacklist required due to:
- some features, e.g. fentry/fexit are not supported in older kernels
- environment limitations, e.g an absence of the recent pahole in Debian
- incomplete disk image
The blacklist is passed to test_progs with -b option as specified in [2]
patch set.
Most of the preceeding tests are disabled due to incomplete disk image currenly
lacking proper networking settings.
For the LATEST kernel fome fentry/fexit tests are disabled due to pahole v1.16
is not abailible in Debian yet.
Next steps are resolving issues with blacklisted tests, enabling maps and
verifier testing, expanding the list of tested kernels.
[1] https://lore.kernel.org/bpf/908498f794661c44dca54da9e09dc0c382df6fcb.1580425879.git.hex@fb.com/t.mbox.gz
[2] https://www.spinics.net/lists/netdev/msg625192.html
vmtest is run as a TravisCI job in order to test libbpf backward compatibility
with the older kernels
Add config files required to build and run bpf kernel selftests in vmtest:
- latest.config: latest kernel config
- INDEX: links to binaries (kernels, disk image) to download
- blacklist/BLACKLIST-${kernel}: blacklisted bpf program tests for ${kernel}
Fix bug requesting invalid size of reallocated array when constructing CO-RE
relocation candidate list. This can cause problems if there are many potential
candidates and a very fine-grained memory allocator bucket sizes are used.
Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: William Smith <williampsmith@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200124201847.212528-1-andriin@fb.com
Previously, if libbpf failed to resolve CO-RE relocation for some
instructions, it would either return error immediately, or, if
.relaxed_core_relocs option was set, would replace relocatable offset/imm part
of an instruction with a bogus value (-1). Neither approach is good, because
there are many possible scenarios where relocation is expected to fail (e.g.,
when some field knowingly can be missing on specific kernel versions). On the
other hand, replacing offset with invalid one can hide programmer errors, if
this relocation failue wasn't anticipated.
This patch deprecates .relaxed_core_relocs option and changes the approach to
always replacing instruction, for which relocation failed, with invalid BPF
helper call instruction. For cases where this is expected, BPF program should
already ensure that that instruction is unreachable, in which case this
invalid instruction is going to be silently ignored. But if instruction wasn't
guarded, BPF program will be rejected at verification step with verifier log
pointing precisely to the place in assembly where the problem is.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200124053837.2434679-1-andriin@fb.com
Add minimal support for program extensions. bpf_object_open_opts() needs to be
called with attach_prog_fd = target_prog_fd and BPF program extension needs to
have in .c file section definition like SEC("freplace/func_to_be_replaced").
libbpf will search for "func_to_be_replaced" in the target_prog_fd's BTF and
will pass it in attach_btf_id to the kernel. This approach works for tests, but
more compex use case may need to request function name (and attach_btf_id that
kernel sees) to be more dynamic. Such API will be added in future patches.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200121005348.2769920-3-ast@kernel.org
This patch introduces the macsec_context structure. It will be used
in the kernel to exchange information between the common MACsec
implementation (macsec.c) and the MACsec hardware offloading
implementations. This structure contains pointers to MACsec specific
structures which contain the actual MACsec configuration, and to the
underlying device (phydev for now).
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current implementation of bpf_object's BTF initialization is very convoluted
and thus prone to errors. It doesn't have to be like that. This patch
simplifies it significantly.
This code also triggered static analysis issues over logically dead code due
to redundant error checks. This simplification should fix that as well.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200117060801.1311525-3-andriin@fb.com
Revert bpf_helpers.h's change to include auto-generated bpf_helper_defs.h
through <> instead of "", which causes it to be searched in include path. This
can break existing applications that don't have their include path pointing
directly to where libbpf installs its headers.
There is ongoing work to make all (not just bpf_helper_defs.h) includes more
consistent across libbpf and its consumers, but this unbreaks user code as is
right now without any regressions. Selftests still behave sub-optimally
(taking bpf_helper_defs.h from libbpf's source directory, if it's present
there), which will be fixed in subsequent patches.
Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Reported-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200117004103.148068-1-andriin@fb.com
This patch exposes bpf_find_kernel_btf() as a LIBBPF_API.
It will be used in 'bpftool map dump' in a following patch
to dump a map with btf_vmlinux_value_type_id set.
bpf_find_kernel_btf() is renamed to libbpf_find_kernel_btf()
and moved to btf.c. As <linux/kernel.h> is included,
some of the max/min type casting needs to be fixed.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200115230031.1102305-1-kafai@fb.com
Added four libbpf API functions to support map batch operations:
. int bpf_map_delete_batch( ... )
. int bpf_map_lookup_batch( ... )
. int bpf_map_lookup_and_delete_batch( ... )
. int bpf_map_update_batch( ... )
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200115184308.162644-8-brianvv@google.com
The LLVM patch https://reviews.llvm.org/D72197 makes LLVM emit function call
relocations within the same section. This includes a default .text section,
which contains any BPF sub-programs. This wasn't the case before and so libbpf
was able to get a way with slightly simpler handling of subprogram call
relocations.
This patch adds support for .text section relocations. It needs to ensure
correct order of relocations, so does two passes:
- first, relocate .text instructions, if there are any relocations in it;
- then process all the other programs and copy over patched .text instructions
for all sub-program calls.
v1->v2:
- break early once .text program is processed.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200115190856.2391325-1-andriin@fb.com
Commit 8b401f9ed244 ("bpf: implement bpf_send_signal() helper")
added helper bpf_send_signal() which permits bpf program to
send a signal to the current process. The signal may be
delivered to any threads in the process.
We found a use case where sending the signal to the current
thread is more preferable.
- A bpf program will collect the stack trace and then
send signal to the user application.
- The user application will add some thread specific
information to the just collected stack trace for
later analysis.
If bpf_send_signal() is used, user application will need
to check whether the thread receiving the signal matches
the thread collecting the stack by checking thread id.
If not, it will need to send signal to another thread
through pthread_kill().
This patch proposed a new helper bpf_send_signal_thread(),
which sends the signal to the thread corresponding to
the current kernel task. This way, user space is guaranteed that
bpf_program execution context and user space signal handling
context are the same thread.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200115035002.602336-1-yhs@fb.com
It's been a recurring issue with types like u32 slipping into libbpf source
code accidentally. This is not detected during builds inside kernel source
tree, but becomes a compilation error in libbpf's Github repo. Libbpf is
supposed to use only __{s,u}{8,16,32,64} typedefs, so poison {s,u}{8,16,32,64}
explicitly in every .c file. Doing that in a bit more centralized way, e.g.,
inside libbpf_internal.h breaks selftests, which are both using kernel u32 and
libbpf_internal.h.
This patch also fixes a new u32 occurence in libbpf.c, added recently.
Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200110181916.271446-1-andriin@fb.com
Reorder includes search path to ensure $(OUTPUT) and $(CURDIR) go before
libbpf's directory. Also fix bpf_helpers.h to include bpf_helper_defs.h in
such a way as to leverage includes search path. This allows selftests to not
use libbpf's local and potentially stale bpf_helper_defs.h. It's important
because selftests/bpf's Makefile only re-generates bpf_helper_defs.h in
seltests' output directory, not the one in libbpf's directory.
Also force regeneration of bpf_helper_defs.h when libbpf.a is updated to
reduce staleness.
Fixes: fa633a0f8919 ("libbpf: Fix build on read-only filesystems")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200110051716.1591485-3-andriin@fb.com
Currently, libbpf re-sorts bpf_map structs after all the maps are added and
initialized, which might change their relative order and invalidate any
bpf_map pointer or index taken before that. This is inconvenient and
error-prone. For instance, it can cause .kconfig map index to point to a wrong
map.
Furthermore, libbpf itself doesn't rely on any specific ordering of bpf_maps,
so it's just an unnecessary complication right now. This patch drops sorting
of maps and makes their relative positions fixed. If efficient index is ever
needed, it's better to have a separate array of pointers as a search index,
instead of reordering bpf_map struct in-place. This will be less error-prone
and will allow multiple independent orderings, if necessary (e.g., either by
section index or by name).
Fixes: 166750bc1dd2 ("libbpf: Support libbpf-provided extern variables")
Reported-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200110034247.1220142-1-andriin@fb.com
Document BPF_F_QUERY_EFFECTIVE flag, mostly to clarify how it affects
attach_flags what may not be obvious and what may lead to confision.
Specifically attach_flags is returned only for target_fd but if programs
are inherited from an ancestor cgroup then returned attach_flags for
current cgroup may be confusing. For example, two effective programs of
same attach_type can be returned but w/o BPF_F_ALLOW_MULTI in
attach_flags.
Simple repro:
# bpftool c s /sys/fs/cgroup/path/to/task
ID AttachType AttachFlags Name
# bpftool c s /sys/fs/cgroup/path/to/task effective
ID AttachType AttachFlags Name
95043 ingress tw_ipt_ingress
95048 ingress tw_ingress
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200108014006.938363-1-rdna@fb.com
This patch adds BPF STRUCT_OPS support to libbpf.
The only sec_name convention is SEC(".struct_ops") to identify the
struct_ops implemented in BPF,
e.g. To implement a tcp_congestion_ops:
SEC(".struct_ops")
struct tcp_congestion_ops dctcp = {
.init = (void *)dctcp_init, /* <-- a bpf_prog */
/* ... some more func prts ... */
.name = "bpf_dctcp",
};
Each struct_ops is defined as a global variable under SEC(".struct_ops")
as above. libbpf creates a map for each variable and the variable name
is the map's name. Multiple struct_ops is supported under
SEC(".struct_ops").
In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops")
section and find out what is the btf-type the struct_ops is
implementing. Note that the btf-type here is referring to
a type in the bpf_prog.o's btf. A "struct bpf_map" is added
by bpf_object__add_map() as other maps do. It will then
collect (through SHT_REL) where are the bpf progs that the
func ptrs are referring to. No btf_vmlinux is needed in
the open phase.
In the bpf_object__load phase, the map-fields, which depend
on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()).
It will also set the prog->type, prog->attach_btf_id, and
prog->expected_attach_type. Thus, the prog's properties do
not rely on its section name.
[ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching
process is as simple as: member-name match + btf-kind match + size match.
If these matching conditions fail, libbpf will reject.
The current targeting support is "struct tcp_congestion_ops" which
most of its members are function pointers.
The member ordering of the bpf_prog's btf-type can be different from
the btf_vmlinux's btf-type. ]
Then, all obj->maps are created as usual (in bpf_object__create_maps()).
Once the maps are created and prog's properties are all set,
the libbpf will proceed to load all the progs.
bpf_map__attach_struct_ops() is added to register a struct_ops
map to a kernel subsystem.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200109003514.3856730-1-kafai@fb.com
Clang patch [0] enables emitting relocatable generic ALU/ALU64 instructions
(i.e, shifts and arithmetic operations), as well as generic load/store
instructions. The former ones are already supported by libbpf as is. This
patch adds further support for load/store instructions. Relocatable field
offset is encoded in BPF instruction's 16-bit offset section and are adjusted
by libbpf based on target kernel BTF.
These Clang changes and corresponding libbpf changes allow for more succinct
generated BPF code by encoding relocatable field reads as a single
ST/LDX/STX instruction. It also enables relocatable access to BPF context.
Previously, if context struct (e.g., __sk_buff) was accessed with CO-RE
relocations (e.g., due to preserve_access_index attribute), it would be
rejected by BPF verifier due to modified context pointer dereference. With
Clang patch, such context accesses are both relocatable and have a fixed
offset from the point of view of BPF verifier.
[0] https://reviews.llvm.org/D71790
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191223180305.86417-1-andriin@fb.com
Introduce a new bpf_prog_attach_xattr function that, in addition to
program fd, target fd and attach type, accepts an extendable struct
bpf_prog_attach_opts.
bpf_prog_attach_opts relies on DECLARE_LIBBPF_OPTS macro to maintain
backward and forward compatibility and has the following "optional"
attach attributes:
* existing attach_flags, since it's not required when attaching in NONE
mode. Even though it's quite often used in MULTI and OVERRIDE mode it
seems to be a good idea to reduce number of arguments to
bpf_prog_attach_xattr;
* newly introduced attribute of BPF_PROG_ATTACH command: replace_prog_fd
that is fd of previously attached cgroup-bpf program to replace if
BPF_F_REPLACE flag is used.
The new function is named to be consistent with other xattr-functions
(bpf_prog_test_run_xattr, bpf_create_map_xattr, bpf_load_program_xattr).
The struct bpf_prog_attach_opts is supposed to be used with
DECLARE_LIBBPF_OPTS macro.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/bd6e0732303eb14e4b79cb128268d9e9ad6db208.1576741281.git.rdna@fb.com
The common use-case in production is to have multiple cgroup-bpf
programs per attach type that cover multiple use-cases. Such programs
are attached with BPF_F_ALLOW_MULTI and can be maintained by different
people.
Order of programs usually matters, for example imagine two egress
programs: the first one drops packets and the second one counts packets.
If they're swapped the result of counting program will be different.
It brings operational challenges with updating cgroup-bpf program(s)
attached with BPF_F_ALLOW_MULTI since there is no way to replace a
program:
* One way to update is to detach all programs first and then attach the
new version(s) again in the right order. This introduces an
interruption in the work a program is doing and may not be acceptable
(e.g. if it's egress firewall);
* Another way is attach the new version of a program first and only then
detach the old version. This introduces the time interval when two
versions of same program are working, what may not be acceptable if a
program is not idempotent. It also imposes additional burden on
program developers to make sure that two versions of their program can
co-exist.
Solve the problem by introducing a "replace" mode in BPF_PROG_ATTACH
command for cgroup-bpf programs being attached with BPF_F_ALLOW_MULTI
flag. This mode is enabled by newly introduced BPF_F_REPLACE attach flag
and bpf_attr.replace_bpf_fd attribute to pass fd of the old program to
replace
That way user can replace any program among those attached with
BPF_F_ALLOW_MULTI flag without the problems described above.
Details of the new API:
* If BPF_F_REPLACE is set but replace_bpf_fd doesn't have valid
descriptor of BPF program, BPF_PROG_ATTACH will return corresponding
error (EINVAL or EBADF).
* If replace_bpf_fd has valid descriptor of BPF program but such a
program is not attached to specified cgroup, BPF_PROG_ATTACH will
return ENOENT.
BPF_F_REPLACE is introduced to make the user intent clear, since
replace_bpf_fd alone can't be used for this (its default value, 0, is a
valid fd). BPF_F_REPLACE also makes it possible to extend the API in the
future (e.g. add BPF_F_BEFORE and BPF_F_AFTER if needed).
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Narkyiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/30cd850044a0057bdfcaaf154b7d2f39850ba813.1576741281.git.rdna@fb.com
zlib is now a direct dependency of libbpf (previously zlib was only dependency
of libelf, on which libbpf depends as well). For non-pkg-config case, specify
`-lz` compiler flag explicitly.
Recent sync also added another public header to libbpf. Include it in a list
of headers that are installed on target system.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Naresh pointed out that libbpf builds fail on 32-bit architectures because
rlimit.rlim_cur is defined as 'unsigned long long' on those architectures.
Fix this by using %zu in printf and casting to size_t.
Fixes: dc3a2d254782 ("libbpf: Print hint about ulimit when getting permission denied error")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191219090236.905059-1-toke@redhat.com
Instead of all or nothing approach of overriding Kconfig file location, allow
to extend it with extra values and override chosen subset of values though
optional user-provided extra config, passed as a string through open options'
.kconfig option. If same config key is present in both user-supplied config
and Kconfig, user-supplied one wins. This allows applications to more easily
test various conditions despite host kernel's real configuration. If all of
BPF object's __kconfig externs are satisfied from user-supplied config, system
Kconfig won't be read at all.
Simplify selftests by not needing to create temporary Kconfig files.
Suggested-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191219002837.3074619-3-andriin@fb.com
There are cases in which BPF resource (program, map, etc) has to outlive
userspace program that "installed" it in the system in the first place.
When BPF program is attached, libbpf returns bpf_link object, which
is supposed to be destroyed after no longer necessary through
bpf_link__destroy() API. Currently, bpf_link destruction causes both automatic
detachment and frees up any resources allocated to for bpf_link in-memory
representation. This is inconvenient for the case described above because of
coupling of detachment and resource freeing.
This patch introduces bpf_link__disconnect() API call, which marks bpf_link as
disconnected from its underlying BPF resouces. This means that when bpf_link
is destroyed later, all its memory resources will be freed, but BPF resource
itself won't be detached.
This design allows to follow strict and resource-leak-free design by default,
while giving easy and straightforward way for user code to opt for keeping BPF
resource attached beyond lifetime of a bpf_link. For some BPF programs (i.e.,
FS-based tracepoints, kprobes, raw tracepoint, etc), user has to make sure to
pin BPF program to prevent kernel to automatically detach it on process exit.
This should typically be achived by pinning BPF program (or map in some cases)
in BPF FS.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191218225039.2668205-1-andriin@fb.com
Drop BPF_EMBED_OBJ and struct bpf_embed_data now that skeleton automatically
embeds contents of its source object file. While BPF_EMBED_OBJ is useful
independently of skeleton, we are currently don't have any use cases utilizing
it, so let's remove them until/if we need it.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218052552.2915188-3-andriin@fb.com
Libbpf is trying to recognize BPF program type based on its section name
during bpf_object__open() phase. This is not strictly enforced and user code
has ability to specify/override correct BPF program type after open. But if
BPF program is using custom section name, libbpf will still emit warnings,
which can be quite annoying to users. This patch reduces log level of
information messages emitted by libbpf if section name is not canonical. User
can still get a list of all supported section names as debug-level message.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191217234228.1739308-1-andriin@fb.com
This fixes two issues with the newly introduced libbpf_common.h file:
- The header failed to include <string.h> for the definition of memset()
- The new file was not included in the install_headers rule in the Makefile
Both of these issues cause breakage when installing libbpf with 'make
install' and trying to use it in applications.
Fixes: 544402d4b493 ("libbpf: Extract common user-facing helpers")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191217112810.768078-1-toke@redhat.com
Probably the single most common error newcomers to XDP are stumped by is
the 'permission denied' error they get when trying to load their program
and 'ulimit -l' is set too low. For examples, see [0], [1].
Since the error code is UAPI, we can't change that. Instead, this patch
adds a few heuristics in libbpf and outputs an additional hint if they are
met: If an EPERM is returned on map create or program load, and geteuid()
shows we are root, and the current RLIMIT_MEMLOCK is not infinity, we
output a hint about raising 'ulimit -l' as an additional log line.
[0] https://marc.info/?l=xdp-newbies&m=157043612505624&w=2
[1] https://github.com/xdp-project/xdp-tutorial/issues/86
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191216181204.724953-1-toke@redhat.com
In btf__align_of() variable name 't' is shadowed by inner block
declaration of another variable with same name. Patch renames
variables in order to fix it.
CC sharedobjs/btf.o
btf.c: In function ‘btf__align_of’:
btf.c:303:21: error: declaration of ‘t’ shadows a previous local [-Werror=shadow]
303 | int i, align = 1, t;
| ^
btf.c:283:25: note: shadowed declaration is here
283 | const struct btf_type *t = btf__type_by_id(btf, id);
|
Fixes: 3d208f4ca111 ("libbpf: Expose btf__align_of() API")
Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20191216082738.28421-1-prashantbhole.linux@gmail.com
Some data stuctures in kernel are defined with either zero-sized array or
flexible (dimensionless) array at the end of a struct. Actual data of such
array follows in memory immediately after the end of that struct, forming its
variable-sized "body" of elements. Support such access pattern in CO-RE
relocation handling.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191215070844.1014385-2-andriin@fb.com
Add support for generation of mmap()-ed read-only view of libbpf-provided
extern variables. As externs are not supposed to be provided by user code
(that's what .data, .bss, and .rodata is for), don't mmap() it initially. Only
after skeleton load is performed, map .extern contents as read-only memory.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014710.3449601-4-andriin@fb.com
Add support for extern variables, provided to BPF program by libbpf. Currently
the following extern variables are supported:
- LINUX_KERNEL_VERSION; version of a kernel in which BPF program is
executing, follows KERNEL_VERSION() macro convention, can be 4- and 8-byte
long;
- CONFIG_xxx values; a set of values of actual kernel config. Tristate,
boolean, strings, and integer values are supported.
Set of possible values is determined by declared type of extern variable.
Supported types of variables are:
- Tristate values. Are represented as `enum libbpf_tristate`. Accepted values
are **strictly** 'y', 'n', or 'm', which are represented as TRI_YES, TRI_NO,
or TRI_MODULE, respectively.
- Boolean values. Are represented as bool (_Bool) types. Accepted values are
'y' and 'n' only, turning into true/false values, respectively.
- Single-character values. Can be used both as a substritute for
bool/tristate, or as a small-range integer:
- 'y'/'n'/'m' are represented as is, as characters 'y', 'n', or 'm';
- integers in a range [-128, 127] or [0, 255] (depending on signedness of
char in target architecture) are recognized and represented with
respective values of char type.
- Strings. String values are declared as fixed-length char arrays. String of
up to that length will be accepted and put in first N bytes of char array,
with the rest of bytes zeroed out. If config string value is longer than
space alloted, it will be truncated and warning message emitted. Char array
is always zero terminated. String literals in config have to be enclosed in
double quotes, just like C-style string literals.
- Integers. 8-, 16-, 32-, and 64-bit integers are supported, both signed and
unsigned variants. Libbpf enforces parsed config value to be in the
supported range of corresponding integer type. Integers values in config can
be:
- decimal integers, with optional + and - signs;
- hexadecimal integers, prefixed with 0x or 0X;
- octal integers, starting with 0.
Config file itself is searched in /boot/config-$(uname -r) location with
fallback to /proc/config.gz, unless config path is specified explicitly
through bpf_object_open_opts' kernel_config_path option. Both gzipped and
plain text formats are supported. Libbpf adds explicit dependency on zlib
because of this, but this shouldn't be a problem, given libelf already depends
on zlib.
All detected extern variables, are put into a separate .extern internal map.
It, similarly to .rodata map, is marked as read-only from BPF program side, as
well as is frozen on load. This allows BPF verifier to track extern values as
constants and perform enhanced branch prediction and dead code elimination.
This can be relied upon for doing kernel version/feature detection and using
potentially unsupported field relocations or BPF helpers in a CO-RE-based BPF
program, while still having a single version of BPF program running on old and
new kernels. Selftests are validating this explicitly for unexisting BPF
helper.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014710.3449601-3-andriin@fb.com
Add new set of APIs, allowing to open/load/attach BPF object through BPF
object skeleton, generated by bpftool for a specific BPF object file. All the
xxx_skeleton() APIs wrap up corresponding bpf_object_xxx() APIs, but
additionally also automate map/program lookups by name, global data
initialization and mmap()-ing, etc. All this greatly improves and simplifies
userspace usability of working with BPF programs. See follow up patches for
examples.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-13-andriin@fb.com
Move BTF ID determination for BPF_PROG_TYPE_TRACING programs to a load phase.
Performing it at open step is inconvenient, because it prevents BPF skeleton
generation on older host kernel, which doesn't contain BTF_KIND_FUNCs
information in vmlinux BTF. This is a common set up, though, when, e.g.,
selftests are compiled on older host kernel, but the test program itself is
executed in qemu VM with bleeding edge kernel. Having this BTF searching
performed at load time allows to successfully use bpf_object__open() for
codegen and inspection of BPF object file.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-11-andriin@fb.com
Refactor global data map initialization to use anonymous mmap()-ed memory
instead of malloc()-ed one. This allows to do a transparent re-mmap()-ing of
already existing memory address to point to BPF map's memory after
bpf_object__load() step (done in follow up patch). This choreographed setup
allows to have a nice and unsurprising way to pre-initialize read-only (and
r/w as well) maps by user and after BPF map creation keep working with
mmap()-ed contents of this map. All in a way that doesn't require user code to
update any pointers: the illusion of working with memory contents is preserved
before and after actual BPF map instantiation.
Selftests and runqslower example demonstrate this feature in follow up patches.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-10-andriin@fb.com
Add APIs to get BPF program function name, as opposed to bpf_program__title(),
which returns BPF program function's section name. Function name has a benefit
of being a valid C identifier and uniquely identifies a specific BPF program,
while section name can be duplicated across multiple independent BPF programs.
Add also bpf_object__find_program_by_name(), similar to
bpf_object__find_program_by_title(), to facilitate looking up BPF programs by
their C function names.
Convert one of selftests to new API for look up.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-9-andriin@fb.com
Expose API that allows to emit type declaration and field/variable definition
(if optional field name is specified) in valid C syntax for any provided BTF
type. This is going to be used by bpftool when emitting data section layout as
a struct. As part of making this API useful in a stand-alone fashion, move
initialization of some of the internal btf_dump state to earlier phase.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-8-andriin@fb.com
LIBBPF_API and DECLARE_LIBBPF_OPTS are needed in many public libbpf API
headers. Extract them into libbpf_common.h to avoid unnecessary
interdependency between btf.h, libbpf.h, and bpf.h or code duplication.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-6-andriin@fb.com
Add a convenience macro BPF_EMBED_OBJ, which allows to embed other files
(typically used to embed BPF .o files) into a hosting userspace programs. To
C program it is exposed as struct bpf_embed_data, containing a pointer to
raw data and its size in bytes.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-5-andriin@fb.com
Generalize BPF program attaching and allow libbpf to auto-detect type (and
extra parameters, where applicable) and attach supported BPF program types
based on program sections. Currently this is supported for:
- kprobe/kretprobe;
- tracepoint;
- raw tracepoint;
- tracing programs (typed raw TP/fentry/fexit).
More types support can be trivially added within this framework.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-3-andriin@fb.com
Reorganize bpf_object__open and bpf_object__load steps such that
bpf_object__open doesn't need root access. This was previously done for
feature probing and BTF sanitization. This doesn't have to happen on open,
though, so move all those steps into the load phase.
This is important, because it makes it possible for tools like bpftool, to
just open BPF object file and inspect their contents: programs, maps, BTF,
etc. For such operations it is prohibitive to require root access. On the
other hand, there is a lot of custom libbpf logic in those steps, so its best
avoided for tools to reimplement all that on their own.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-2-andriin@fb.com
It's quite common on some systems to have more CPUs enlisted as "possible",
than there are (and could ever be) present/online CPUs. In such cases,
perf_buffer creationg will fail due to inability to create perf event on
missing CPU with error like this:
libbpf: failed to open perf buffer event on cpu #16: No such device
This patch fixes the logic of perf_buffer__new() to ignore CPUs that are
missing or currently offline. In rare cases where user explicitly listed
specific CPUs to connect to, behavior is unchanged: libbpf will try to open
perf event buffer on specified CPU(s) anyways.
Fixes: fb84b8224655 ("libbpf: add perf buffer API")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212013609.1691168-1-andriin@fb.com
This logic is re-used for parsing a set of online CPUs. Having it as an
isolated piece of code working with input string makes it conveninent to test
this logic as well. While refactoring, also improve the robustness of original
implementation.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212013548.1690564-1-andriin@fb.com
Allow loading BPF object files that contain SK_REUSEPORT programs without
having to manually set the program type before load if the the section name
is set to "sk_reuseport".
Makes user-space code needed to load SK_REUSEPORT BPF program more concise.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212102259.418536-2-jakub@cloudflare.com
A follow up of [1]
Travis CI stages use default phases when no override provided.
This leads to Coverity scan stage fail due to execuing the default
before_script: phase of VMTEST.
Fix this with an explicit override with empty value.
[1] https://github.com/libbpf/libbpf/pull/108
Extend continuous integration tests by adding testing against various kernel
versions.
The code is based on vmtest CI scripts implemented by osandov@
for drgn [1] with the following modifications:
- The downloadables are stored in Amazon S3 cloud indexed in [2]
- `--setup-cmd` command line option is added to vmtest/run.sh so
setup commands run on VM boot can be set in e.g. `.travis.yml`
- Travis build matrix [2] is introduced for VM tests so VM tests are
followed by the existing CI tests. The matrix has `KERNEL` and
`VMTEST_SETUPCMD` dimensions.
- Minor style fixes.
The vmtest extention code is located in travis-ci/vmtest and contains
`run.sh` and `setup_example.sh`
- `run.sh` is responsible for the vmtest workflow: downloading vmlinux
and rootfs image from the cloud, fs mounting, syncing libbpf sources
to the image, setting up scripts run on VM boot, starting VM using
QEMU.
`run.sh` covers more use cases than a script for a job run in TravisCI,
e.g. int can build a kernel w/ `--build` option.
- `setup_example.sh` is an example of a script run in VM which can be
modified to e.g. run actual libbpf tests. A setup script should have
executable permission.
To set up a new kernel version for a test:
1) upload vmlinuz.* and vmlinux.*\.zst to Amazon S3 store
located at [4];
2) modify INDEX [2] file.
[1] https://github.com/osandov/drgn
[2] https://libbpf-vmtest.s3-us-west-1.amazonaws.com/x86_64/INDEX
[3] https://docs.travis-ci.com/user/build-matrix
[4] https://libbpf-vmtest.s3-us-west-1.amazonaws.com/
On ppc64le __u64 and __s64 are defined as long int and unsigned long int,
respectively. This causes compiler to emit warning when %lld/%llu are used to
printf 64-bit numbers. Fix this by casting to size_t/ssize_t with %zu and %zd
format specifiers, respectively.
v1->v2:
- use size_t/ssize_t instead of custom typedefs (Martin).
Fixes: 1f8e2bcb2cd5 ("libbpf: Refactor relocation handling")
Fixes: abd29c931459 ("libbpf: allow specifying map definitions using BTF")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191212171918.638010-1-andriin@fb.com
These were added to the kernel repo, but not in Github. However, they are
useful for browsing the source in Github while prototyping new features and
compiling them into userspace utilities.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
2019-12-11 10:38:48 -08:00
53 changed files with 93133 additions and 1525 deletions
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