kernel/linux.git/tools/bpf/bpftool/feature.c, branch linux-6.12.y

bpftool: fix some typos in bpftool

2024-09-05T20:07:47+00:00

Hi, fix some spelling errors in bpftool, the details are as follows: -in file "bpftool-gen.rst" libppf->libbpf -in the code comments: ouptut->output Signed-off-by: Lin Yikai Link: https://lore.kernel.org/r/20240905110354.3274546-2-yikai.lin@vivo.com Signed-off-by: Alexei Starovoitov

bpf: improve error message for unsupported helper

2024-03-29T01:30:53+00:00

BPF verifier emits "unknown func" message when given BPF program type does not support BPF helper. This message may be confusing for users, as important context that helper is unknown only to current program type is not provided. This patch changes message to "program of this type cannot use helper " and aligns dependent code in libbpf and tests. Any suggestions on improving/changing this message are welcome. Signed-off-by: Mykyta Yatsenko Acked-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/r/20240325152210.377548-1-yatsenko@meta.com Signed-off-by: Alexei Starovoitov

bpfilter: remove bpfilter

2024-01-04T18:23:10+00:00

bpfilter was supposed to convert iptables filtering rules into BPF programs on the fly, from the kernel, through a usermode helper. The base code for the UMH was introduced in 2018, and couple of attempts (2, 3) tried to introduce the BPF program generate features but were abandoned. bpfilter now sits in a kernel tree unused and unusable, occasionally causing confusion amongst Linux users (4, 5). As bpfilter is now developed in a dedicated repository on GitHub (6), it was suggested a couple of times this year (LSFMM/BPF 2023, LPC 2023) to remove the deprecated kernel part of the project. This is the purpose of this patch. [1]: https://lore.kernel.org/lkml/20180522022230.2492505-1-ast@kernel.org/ [2]: https://lore.kernel.org/bpf/20210829183608.2297877-1-me@ubique.spb.ru/#t [3]: https://lore.kernel.org/lkml/20221224000402.476079-1-qde@naccy.de/ [4]: https://dxuuu.xyz/bpfilter.html [5]: https://github.com/linuxkit/linuxkit/pull/3904 [6]: https://github.com/facebook/bpfilter Signed-off-by: Quentin Deslandes Link: https://lore.kernel.org/r/20231226130745.465988-1-qde@naccy.de Signed-off-by: Alexei Starovoitov

bpftool: Use "fallthrough;" keyword instead of comments

2023-07-12T21:50:11+00:00

After using "__fallthrough;" in a switch/case block in bpftool's btf_dumper.c [0], and then turning it into a comment [1] to prevent a merge conflict in linux-next when the keyword was changed into just "fallthrough;" [2], we can now drop the comment and use the new keyword, no underscores. Also update the other occurrence of "/* fallthrough */" in bpftool. [0] commit 9fd496848b1c ("bpftool: Support inline annotations when dumping the CFG of a program") [1] commit 4b7ef71ac977 ("bpftool: Replace "__fallthrough" by a comment to address merge conflict") [2] commit f7a858bffcdd ("tools: Rename __fallthrough to fallthrough") Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20230712152322.81758-1-quentin@isovalent.com

bpftool: JIT limited misreported as negative value on aarch64

2023-05-15T19:14:48+00:00

On aarch64, "bpftool feature" reports an incorrect BPF JIT limit: $ sudo /sbin/bpftool feature Scanning system configuration... bpf() syscall restricted to privileged users JIT compiler is enabled JIT compiler hardening is disabled JIT compiler kallsyms exports are enabled for root skipping kernel config, can't open file: No such file or directory Global memory limit for JIT compiler for unprivileged users is -201326592 bytes This is because /proc/sys/net/core/bpf_jit_limit reports $ sudo cat /proc/sys/net/core/bpf_jit_limit 68169519595520 ...and an int is assumed in read_procfs(). Change read_procfs() to return a long to avoid negative value reporting. Fixes: 7a4522bbef0c ("tools: bpftool: add probes for /proc/ eBPF parameters") Reported-by: Nicky Veitch Signed-off-by: Alan Maguire Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20230512113134.58996-1-alan.maguire@oracle.com

bpftool: fix output for skipping kernel config check

2023-01-11T01:42:31+00:00

When bpftool feature does not find kernel config files under default path or wrong format, do not output CONFIG_XYZ is not set. Skip kernel config check and continue. Signed-off-by: Chethan Suresh Signed-off-by: Kenta Tada Acked-by: Quentin Monnet Link: https://lore.kernel.org/r/20230109023742.29657-1-chethan.suresh@sony.com Signed-off-by: Martin KaFai Lau

bpftool: Fix a typo in a comment

2022-08-15T15:29:42+00:00

This is the wrong library name: libcap, not libpcap. Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220812153727.224500-1-quentin@isovalent.com

bpftool: Rename "bpftool feature list" into "... feature list_builtins"

2022-07-05T09:53:54+00:00

To make it more explicit that the features listed with "bpftool feature list" are known to bpftool, but not necessary available on the system (as opposed to the probed features), rename the "feature list" command into "feature list_builtins". Note that "bpftool feature list" still works as before given that we recognise arguments from their prefixes; but the real name of the subcommand, in particular as displayed in the man page or the interactive help, will now include "_builtins". Since we update the bash completion accordingly, let's also take this chance to redirect error output to /dev/null in the completion script, to avoid displaying unexpected error messages when users attempt to tab-complete. Suggested-by: Daniel Borkmann Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220701093805.16920-1-quentin@isovalent.com

bpftool: Add feature list (prog/map/link/attach types, helpers)

2022-06-30T14:17:03+00:00

Add a "bpftool feature list" subcommand to list BPF "features". Contrarily to "bpftool feature probe", this is not about the features available on the system. Instead, it lists all features known to bpftool from compilation time; in other words, all program, map, attach, link types known to the libbpf version in use, and all helpers found in the UAPI BPF header. The first use case for this feature is bash completion: running the command provides a list of types that can be used to produce the list of candidate map types, for example. Now that bpftool uses "standard" names provided by libbpf for the program, map, link, and attach types, having the ability to list these types and helpers could also be useful in scripts to loop over existing items. Sample output: # bpftool feature list prog_types | grep -vw unspec | head -n 6 socket_filter kprobe sched_cls sched_act tracepoint xdp # bpftool -p feature list map_types | jq '.[1]' "hash" # bpftool feature list attach_types | grep '^cgroup_' cgroup_inet_ingress cgroup_inet_egress [...] cgroup_inet_sock_release # bpftool feature list helpers | grep -vw bpf_unspec | wc -l 207 The "unspec" types and helpers are not filtered out by bpftool, so as to remain closer to the enums, and to preserve the indices in the JSON arrays (e.g. "hash" at index 1 == BPF_MAP_TYPE_HASH in map types list). Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Acked-by: Daniel Müller Link: https://lore.kernel.org/bpf/20220629203637.138944-2-quentin@isovalent.com

Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"

2022-06-14T20:18:06+00:00

This reverts commit a777e18f1bcd32528ff5dfd10a6629b655b05eb8. In commit a777e18f1bcd ("bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"), we removed the rlimit bump in bpftool, because the kernel has switched to memcg-based memory accounting. Thanks to the LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK, we attempted to keep compatibility with other systems and ask libbpf to raise the limit for us if necessary. How do we know if memcg-based accounting is supported? There is a probe in libbpf to check this. But this probe currently relies on the availability of a given BPF helper, bpf_ktime_get_coarse_ns(), which landed in the same kernel version as the memory accounting change. This works in the generic case, but it may fail, for example, if the helper function has been backported to an older kernel. This has been observed for Google Cloud's Container-Optimized OS (COS), where the helper is available but rlimit is still in use. The probe succeeds, the rlimit is not raised, and probing features with bpftool, for example, fails. A patch was submitted [0] to update this probe in libbpf, based on what the cilium/ebpf Go library does [1]. It would lower the soft rlimit to 0, attempt to load a BPF object, and reset the rlimit. But it may induce some hard-to-debug flakiness if another process starts, or the current application is killed, while the rlimit is reduced, and the approach was discarded. As a workaround to ensure that the rlimit bump does not depend on the availability of a given helper, we restore the unconditional rlimit bump in bpftool for now. [0] https://lore.kernel.org/bpf/20220609143614.97837-1-quentin@isovalent.com/ [1] https://github.com/cilium/ebpf/blob/v0.9.0/rlimit/rlimit.go#L39 Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Cc: Yafang Shao Cc: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20220610112648.29695-2-quentin@isovalent.com