The CHECK message contains a spelling mistake, fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
At LPC 2018 in Vancouver, Vlad Dumitrescu mentioned that longest_prefix_match()
has a high cost [1].
One reason for that cost is a loop handling one byte at a time.
We can handle more bytes at a time, if enough attention is paid
to endianness.
I was able to remove ~55 % of longest_prefix_match() cpu costs.
[1] https://linuxplumbersconf.org/event/2/contributions/88/attachments/76/87/lpc-bpf-2018-shaping.pdf
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Dumitrescu <vladum@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Nikita V. Shirokov says:
====================
In this patch series I'm adding a helper for libbpf which would allow
it to load map-in-map(BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS).
First patch contains new helper + explains proposed workflow second patch
contains tests which also could be used as example usage.
v4->v5:
- naming: renamed everything to map_in_map instead of mapinmap
- start to return nonzero val if set_inner_map_fd failed
v3->v4:
- renamed helper to set_inner_map_fd
- now we set this value only if it haven't
been set before and only for (array|hash) of maps
v2->v3:
- fixing typo in patch description
- initializing inner_map_fd to -1 by default
v1->v2:
- addressing nits
- removing const identifier from fd in new helper
- starting to check return val for bpf_map_update_elem
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
adding test/example of bpf_map__set_inner_map_fd usage
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
idea is pretty simple. for specified map (pointed by struct bpf_map)
we would provide descriptor of already loaded map, which is going to be
used as a prototype for inner map. proposed workflow:
1) open bpf's object (bpf_object__open)
2) create bpf's map which is going to be used as a prototype
3) find (by name) map-in-map which you want to load and update w/
descriptor of inner map w/ a new helper from this patch
4) load bpf program w/ bpf_object__load
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Use recently added capability check.
See commit 23499442c3 ("bpf: libbpf: retry map creation without
the name") for rationale.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Instead, check for a newly created caps.name bpf_object capability.
If kernel doesn't support names, don't specify the attribute.
See commit 23499442c3 ("bpf: libbpf: retry map creation without
the name") for rationale.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
It currently only checks whether kernel supports map/prog names.
This capability check will be used in the next two commits to
skip setting prog/map names.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Wrap headers in extern "C", to turn off C++ mangling.
This simplifies including libbpf in c++ and linking against it.
v2 changes:
* do the same for btf.h
v3 changes:
* test_libbpf.cpp to test for possible future c++ breakages
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Commit 2993e0515b ("tools/bpf: add support to read .BTF.ext sections")
added support to read .BTF.ext sections from an object file, create
and pass prog_btf_fd and func_info to the kernel.
The program btf_fd (prog->btf_fd) is initialized to be -1 to please
zclose so we do not need special handling dur prog close.
Passing -1 to the kernel, however, will cause loading error.
Passing btf_fd 0 to the kernel if prog->btf_fd is invalid
fixed the problem.
Fixes: 2993e0515b ("tools/bpf: add support to read .BTF.ext sections")
Reported-by: Andrey Ignatov <rdna@fb.com>
Reported-by: Emre Cantimur <haydum@fb.com>
Tested-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Kernel test robot (lkp@intel.com) reports a compilation error at
https://www.spinics.net/lists/netdev/msg534913.html
introduced by commit 838e96904f ("bpf: Introduce bpf_func_info").
If CONFIG_BPF is defined and CONFIG_BPF_SYSCALL is not defined,
the following error will appear:
kernel/bpf/core.c:414: undefined reference to `btf_type_by_id'
kernel/bpf/core.c:415: undefined reference to `btf_name_by_offset'
When CONFIG_BPF_SYSCALL is not defined,
let us define stub inline functions for btf_type_by_id()
and btf_name_by_offset() in include/linux/btf.h.
This way, the compilation failure can be avoided.
Fixes: 838e96904f ("bpf: Introduce bpf_func_info")
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martin KaFai Lau says:
====================
The BTF support was added to kernel by Commit 69b693f0ae
("bpf: btf: Introduce BPF Type Format (BTF)"), which introduced
.BTF section into ELF file and is primarily
used for map pretty print.
pahole is used to convert dwarf to BTF for ELF files.
This patch added func info support to the kernel so we can
get better ksym's for bpf function calls. Basically,
function call types are passed to kernel and the kernel
extract function names from these types in order to contruct ksym
for these functions.
The llvm patch at https://reviews.llvm.org/D53736
will generate .BTF section and one more section .BTF.ext.
The .BTF.ext section encodes function type
information. The following is a sample output for selftests
test_btf with file test_btf_haskv.o for translated insns
and jited insns respectively.
$ bpftool prog dump xlated id 1
int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
0: (85) call pc+2#bpf_prog_2dcecc18072623fc_test_long_fname_1
1: (b7) r0 = 0
2: (95) exit
int test_long_fname_1(struct dummy_tracepoint_args * arg):
3: (85) call pc+1#bpf_prog_89d64e4abf0f0126_test_long_fname_2
4: (95) exit
int test_long_fname_2(struct dummy_tracepoint_args * arg):
5: (b7) r2 = 0
6: (63) *(u32 *)(r10 -4) = r2
7: (79) r1 = *(u64 *)(r1 +8)
...
22: (07) r1 += 1
23: (63) *(u32 *)(r0 +4) = r1
24: (95) exit
$ bpftool prog dump jited id 1
int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
bpf_prog_b07ccb89267cf242__dummy_tracepoint:
0: push %rbp
1: mov %rsp,%rbp
......
3c: add $0x28,%rbp
40: leaveq
41: retq
int test_long_fname_1(struct dummy_tracepoint_args * arg):
bpf_prog_2dcecc18072623fc_test_long_fname_1:
0: push %rbp
1: mov %rsp,%rbp
......
3a: add $0x28,%rbp
3e: leaveq
3f: retq
int test_long_fname_2(struct dummy_tracepoint_args * arg):
bpf_prog_89d64e4abf0f0126_test_long_fname_2:
0: push %rbp
1: mov %rsp,%rbp
......
80: add $0x28,%rbp
84: leaveq
85: retq
Changelogs:
v4 -> v5:
. Add back BTF_KIND_FUNC_PROTO as v1 did. The difference
is BTF_KIND_FUNC_PROTO cannot have t->name_off now.
All param metadata is defined in BTF_KIND_FUNC_PROTO.
BTF_KIND_FUNC must have t->name_off != 0 and t->type
refers to a BTF_KIND_FUNC_PROTO.
The above is the conclusion after the discussion between
Edward Cree, Alexei, Daniel, Yonghong and Martin.
v3 -> v4:
. Remove BTF_KIND_FUNC_PROTO. BTF_KIND_FUNC is used for
both function pointer and subprogram. The name_off field
is used to distinguish both.
. The record size is added to the func_info subsection
in .BTF.ext to enable future extension.
. The bpf_prog_info interface change to make it similar
bpf_prog_load.
. Related kernel and libbpf changes to accommodate the
new .BTF.ext and kernel interface changes.
v2 -> v3:
. Removed kernel btf extern functions btf_type_id_func()
and btf_get_name_by_id(). Instead, exposing existing
functions btf_type_by_id() and btf_name_by_offset().
. Added comments about ELF section .BTF.ext layout.
. Better codes in btftool as suggested by Edward Cree.
v1 -> v2:
. Added missing sign-off.
. Limited the func_name/struct_member_name length for validity test.
. Removed/changed several verifier messages.
. Modified several commit messages to remove line_off reference.
====================
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Change the bpf programs test_btf_haskv.c and test_btf_nokv.c to
have two sections, and enhance test_btf.c test_file feature
to test btf func_info returned by the kernel.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The function get_btf() is implemented in tools/bpf/bpftool/map.c
to get a btf structure given a map_info. This patch
refactored this function to be function btf_get_from_id()
in tools/lib/bpf so that it can be used later.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add additional checks in tools/testing/selftests/bpf and
samples/bpf such that if clang/llvm compiler can generate
BTF sections, do not use pahole.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The .BTF section is already available to encode types.
These types can be used for map
pretty print. The whole .BTF will be passed to the
kernel as well for which kernel can verify and return
to the user space for pretty print etc.
The llvm patch at https://reviews.llvm.org/D53736
will generate .BTF section and one more section .BTF.ext.
The .BTF.ext section encodes function type
information and line information. Note that
this patch set only supports function type info.
The functionality is implemented in libbpf.
The .BTF section can be directly loaded into the
kernel, and the .BTF.ext section cannot. The loader
may need to do some relocation and merging,
similar to merging multiple code sections, before
loading into the kernel.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A two function bpf program is loaded with btf and func_info.
After successful prog load, the bpf_get_info syscall is called
to retrieve prog info to ensure the types returned from the
kernel matches the types passed to the kernel from the
user space.
Several negative tests are also added to test loading/retriving
of func_type info.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The new fields are added for program load in lib/bpf so
application uses api bpf_load_program_xattr() is able
to load program with btf and func_info data.
This functionality will be used in next patch
by bpf selftest test_btf.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The kernel uapi bpf.h is synced to tools directory.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch added interface to load a program with the following
additional information:
. prog_btf_fd
. func_info, func_info_rec_size and func_info_cnt
where func_info will provide function range and type_id
corresponding to each function.
The func_info_rec_size is introduced in the UAPI to specify
struct bpf_func_info size passed from user space. This
intends to make bpf_func_info structure growable in the future.
If the kernel gets a different bpf_func_info size from userspace,
it will try to handle user request with part of bpf_func_info
it can understand. In this patch, kernel can understand
struct bpf_func_info {
__u32 insn_offset;
__u32 type_id;
};
If user passed a bpf func_info record size of 16 bytes, the
kernel can still handle part of records with the above definition.
If verifier agrees with function range provided by the user,
the bpf_prog ksym for each function will use the func name
provided in the type_id, which is supposed to provide better
encoding as it is not limited by 16 bytes program name
limitation and this is better for bpf program which contains
multiple subprograms.
The bpf_prog_info interface is also extended to
return btf_id, func_info, func_info_rec_size and func_info_cnt
to userspace, so userspace can print out the function prototype
for each xlated function. The insn_offset in the returned
func_info corresponds to the insn offset for xlated functions.
With other jit related fields in bpf_prog_info, userspace can also
print out function prototypes for each jited function.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds unit tests for BTF_KIND_FUNC_PROTO and
BTF_KIND_FUNC to test_btf.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The kernel uapi btf.h is synced to the tools directory.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO
to support the function debug info.
BTF_KIND_FUNC_PROTO must not have a name (i.e. !t->name_off)
and it is followed by >= 0 'struct bpf_param' objects to
describe the function arguments.
The BTF_KIND_FUNC must have a valid name and it must
refer back to a BTF_KIND_FUNC_PROTO.
The above is the conclusion after the discussion between
Edward Cree, Alexei, Daniel, Yonghong and Martin.
By combining BTF_KIND_FUNC and BTF_LIND_FUNC_PROTO,
a complete function signature can be obtained. It will be
used in the later patches to learn the function signature of
a running bpf program.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch breaks up btf_type_is_void() into
btf_type_is_void() and btf_type_is_fwd().
It also adds btf_type_nosize() to better describe it is
testing a type has nosize info.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Lorenz Bauer says:
====================
Allow forcing the seed of a hash table to zero, for deterministic
execution during benchmarking and testing.
Changes from v2:
* Change ordering of BPF_F_ZERO_SEED in linux/bpf.h
Comments adressed from v1:
* Add comment to discourage production use to linux/bpf.h
* Require CAP_SYS_ADMIN
====================
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Check that iterating two separate hash maps produces the same
order of keys if BPF_F_ZERO_SEED is used.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
BPF_F_QUERY_EFFECTIVE is in the middle of the flags valid
for BPF_MAP_CREATE. Move it to its own section to reduce confusion.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Add a new flag BPF_F_ZERO_SEED, which forces a hash map
to initialize the seed to zero. This is useful when doing
performance analysis both on individual BPF programs, as
well as the kernel's hash table implementation.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Since commit 88cda1c9da ("bpf: libbpf: Provide basic API support
to specify BPF obj name"), libbpf unconditionally sets bpf_attr->name
for maps. Pre v4.14 kernels don't know about map names and return an
error about unexpected non-zero data. Retry sys_bpf without a map
name to cover older kernels.
v2 changes:
* check for errno == EINVAL as suggested by Daniel Borkmann
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Pointer offload is being null checked however the following statement
dereferences the potentially null pointer offload when assigning
offload->dev_state. Fix this by only assigning it if offload is not
null.
Detected by CoverityScan, CID#1475437 ("Dereference after null check")
Fixes: 00db12c3d1 ("bpf: call verifier_prep from its callback in struct bpf_offload_dev")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make it possible to build bpftool without libbfd. libbfd and libopcodes are
typically provided in dev/dbg packages (binutils-dev in debian) which we
usually don't have installed on the fleet machines and we'd like a way to have
bpftool version that works without installing any additional packages.
This excludes support for disassembling jit-ted code and prints an error if
the user tries to use these features.
Tested by:
cat > FEATURES_DUMP.bpftool <<EOF
feature-libbfd=0
feature-disassembler-four-args=1
feature-reallocarray=0
feature-libelf=1
feature-libelf-mmap=1
feature-bpf=1
EOF
FEATURES_DUMP=$PWD/FEATURES_DUMP.bpftool make
ldd bpftool | grep libbfd
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrey Ignatov says:
====================
This patch set makes bpf_sk_lookup_tcp, bpf_sk_lookup_udp and
bpf_sk_release helpers available in programs of type
BPF_PROG_TYPE_CGROUP_SOCK_ADDR.
Patch 1 is a fix for bpf_sk_lookup_udp that was already merged to bpf
(stable) tree. Here it's prerequisite for patch 3.
Patch 2 is the main patch in the set, it makes the helpers available for
BPF_PROG_TYPE_CGROUP_SOCK_ADDR and provides more details about use-case.
Patch 3 adds selftest for new functionality.
v1->v2:
- remove "Split bpf_sk_lookup" patch since it was already split by:
commit c8123ead13 ("bpf: Extend the sk_lookup() helper to XDP
hookpoint.");
- avoid unnecessary bpf_sock_addr_sk_lookup function.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Use bpf_sk_lookup_tcp, bpf_sk_lookup_udp and bpf_sk_release helpers from
test_sock_addr programs to make sure they're available and can lookup
and release socket properly for IPv4/IPv4, TCP/UDP.
Reading from a few fields of returned struct bpf_sock is also tested.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make bpf_sk_lookup_tcp, bpf_sk_lookup_udp and bpf_sk_release helpers
available in programs of type BPF_PROG_TYPE_CGROUP_SOCK_ADDR.
Such programs operate on sockets and have access to socket and struct
sockaddr passed by user to system calls such as sys_bind, sys_connect,
sys_sendmsg.
It's useful to be able to lookup other sockets from these programs.
E.g. sys_connect may lookup IP:port endpoint and if there is a server
socket bound to that endpoint ("server" can be defined by saddr & sport
being zero), redirect client connection to it by rewriting IP:port in
sockaddr passed to sys_connect.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Lookup functions in sk_lookup have different expectations about byte
order of provided arguments.
Specifically __inet_lookup, __udp4_lib_lookup and __udp6_lib_lookup
expect dport to be in network byte order and do ntohs(dport) internally.
At the same time __inet6_lookup expects dport to be in host byte order
and correspondingly name the argument hnum.
sk_lookup works correctly with __inet_lookup, __udp4_lib_lookup and
__inet6_lookup with regard to dport. But in __udp6_lib_lookup case it
uses host instead of expected network byte order. It makes result
returned by bpf_sk_lookup_udp for IPv6 incorrect.
The patch fixes byte order of dport passed to __udp6_lib_lookup.
Originally sk_lookup properly handled UDPv6, but not TCPv6. 5ef0ae84f0
fixes TCPv6 but breaks UDPv6.
Fixes: 5ef0ae84f0 ("bpf: Fix IPv6 dport byte-order in bpf_sk_lookup")
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch restores the behavior in
commit eac7d84519 ("tools: libbpf: don't return '.text' as a program for multi-function programs")
such that bpf_program__next() does not return pseudo programs in ".text".
Fixes: 0c19a9fbc9 ("libbpf: cleanup after partial failure in bpf_object__pin")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann reports:
test_progs.c: In function ‘main’:
test_progs.c:81:3: warning: ‘duration’ may be used uninitialized in this function [-Wmaybe-uninitialized]
printf("%s:PASS:%s %d nsec\n", __func__, tag, duration);\
^~~~~~
test_progs.c:1706:8: note: ‘duration’ was declared here
__u32 duration;
^~~~~~~~
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrey Ignatov says:
====================
This patch set adds support for narrow loads with offset > 0 to BPF
verifier.
Patch 1 provides more details and is the main patch in the set.
Patches 2 and 3 add new test cases to test_verifier and test_sock_addr
selftests.
v1->v2:
- fix -Wdeclaration-after-statement warning.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add more test cases for context bpf_sock_addr to test narrow loads with
offset > 0 for ctx->user_ip4 field (__u32):
* off=1, size=1;
* off=2, size=1;
* off=3, size=1;
* off=2, size=2.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently BPF verifier allows narrow loads for a context field only with
offset zero. E.g. if there is a __u32 field then only the following
loads are permitted:
* off=0, size=1 (narrow);
* off=0, size=2 (narrow);
* off=0, size=4 (full).
On the other hand LLVM can generate a load with offset different than
zero that make sense from program logic point of view, but verifier
doesn't accept it.
E.g. tools/testing/selftests/bpf/sendmsg4_prog.c has code:
#define DST_IP4 0xC0A801FEU /* 192.168.1.254 */
...
if ((ctx->user_ip4 >> 24) == (bpf_htonl(DST_IP4) >> 24) &&
where ctx is struct bpf_sock_addr.
Some versions of LLVM can produce the following byte code for it:
8: 71 12 07 00 00 00 00 00 r2 = *(u8 *)(r1 + 7)
9: 67 02 00 00 18 00 00 00 r2 <<= 24
10: 18 03 00 00 00 00 00 fe 00 00 00 00 00 00 00 00 r3 = 4261412864 ll
12: 5d 32 07 00 00 00 00 00 if r2 != r3 goto +7 <LBB0_6>
where `*(u8 *)(r1 + 7)` means narrow load for ctx->user_ip4 with size=1
and offset=3 (7 - sizeof(ctx->user_family) = 3). This load is currently
rejected by verifier.
Verifier code that rejects such loads is in bpf_ctx_narrow_access_ok()
what means any is_valid_access implementation, that uses the function,
works this way, e.g. bpf_skb_is_valid_access() for __sk_buff or
sock_addr_is_valid_access() for bpf_sock_addr.
The patch makes such loads supported. Offset can be in [0; size_default)
but has to be multiple of load size. E.g. for __u32 field the following
loads are supported now:
* off=0, size=1 (narrow);
* off=1, size=1 (narrow);
* off=2, size=1 (narrow);
* off=3, size=1 (narrow);
* off=0, size=2 (narrow);
* off=2, size=2 (narrow);
* off=0, size=4 (full).
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stanislav Fomichev says:
====================
v5 changes:
* FILE -> PATH for load/loadall (can be either file or directory now)
* simpler implementation for __bpf_program__pin_name
* removed p_err for REQ_ARGS checks
* parse_atach_detach_args -> parse_attach_detach_args
* for -> while in bpf_object__pin_{programs,maps} recovery
v4 changes:
* addressed another round of comments/style issues from Jakub Kicinski &
Quentin Monnet (thanks!)
* implemented bpf_object__pin_maps and bpf_object__pin_programs helpers and
used them in bpf_program__pin
* added new pin_name to bpf_program so bpf_program__pin
works with sections that contain '/'
* moved *loadall* command implementation into a separate patch
* added patch that implements *pinmaps* to pin maps when doing
load/loadall
v3 changes:
* (maybe) better cleanup for partial failure in bpf_object__pin
* added special case in bpf_program__pin for programs with single
instances
v2 changes:
* addressed comments/style issues from Jakub Kicinski & Quentin Monnet
* removed logic that populates jump table
* added cleanup for partial failure in bpf_object__pin
This patch series adds support for loading and attaching flow dissector
programs from the bpftool:
* first patch fixes flow dissector section name in the selftests (so
libbpf auto-detection works)
* second patch adds proper cleanup to bpf_object__pin, parts of which are now
being used to attach all flow dissector progs/maps
* third patch adds special case in bpf_program__pin for programs with
single instances (we don't create <prog>/0 pin anymore, just <prog>)
* forth patch adds pin_name to the bpf_program struct
which is now used as a pin name in bpf_program__pin et al
* fifth patch adds *loadall* command that pins all programs, not just
the first one
* sixth patch adds *pinmaps* argument to load/loadall to let users pin
all maps of the obj file
* seventh patch adds actual flow_dissector support to the bpftool and
an example
====================
Acked-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit adds support for loading/attaching/detaching flow
dissector program.
When `bpftool loadall` is called with a flow_dissector prog (i.e. when the
'type flow_dissector' argument is passed), we load and pin all programs.
User is responsible to construct the jump table for the tail calls.
The last argument of `bpftool attach` is made optional for this use
case.
Example:
bpftool prog load tools/testing/selftests/bpf/bpf_flow.o \
/sys/fs/bpf/flow type flow_dissector \
pinmaps /sys/fs/bpf/flow
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 0 0 0 0 \
value pinned /sys/fs/bpf/flow/IP
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 1 0 0 0 \
value pinned /sys/fs/bpf/flow/IPV6
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 2 0 0 0 \
value pinned /sys/fs/bpf/flow/IPV6OP
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 3 0 0 0 \
value pinned /sys/fs/bpf/flow/IPV6FR
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 4 0 0 0 \
value pinned /sys/fs/bpf/flow/MPLS
bpftool map update pinned /sys/fs/bpf/flow/jmp_table \
key 5 0 0 0 \
value pinned /sys/fs/bpf/flow/VLAN
bpftool prog attach pinned /sys/fs/bpf/flow/flow_dissector flow_dissector
Tested by using the above lines to load the prog in
the test_flow_dissector.sh selftest.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This new additional argument lets users pin all maps from the object at
specified path.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds new *loadall* command which slightly differs from the
existing *load*. *load* command loads all programs from the obj file,
but pins only the first programs. *loadall* pins all programs from the
obj file under specified directory.
The intended usecase is flow_dissector, where we want to load a bunch
of progs, pin them all and after that construct a jump table.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
pin_name is the same as section_name where '/' is replaced
by '_'. bpf_object__pin_programs is converted to use pin_name
to avoid the situation where section_name would require creating another
subdirectory for a pin (as, for example, when calling bpf_object__pin_programs
for programs in sections like "cgroup/connect6").
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When bpf_program has only one instance, don't create a subdirectory with
per-instance pin files (<prog>/0). Instead, just create a single pin file
for that single instance. This simplifies object pinning by not creating
unnecessary subdirectories.
This can potentially break existing users that depend on the case
where '/0' is always created. However, I couldn't find any serious
usage of bpf_program__pin inside the kernel tree and I suppose there
should be none outside.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Colin Ian King