2019-01-17 15:27:50 +00:00
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===============
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bpftool-feature
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===============
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-------------------------------------------------------------------------------
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tool for inspection of eBPF-related parameters for Linux kernel or net device
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-------------------------------------------------------------------------------
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:Manual section: 8
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **feature** *COMMAND*
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*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
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*COMMANDS* := { **probe** | **help** }
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2019-02-06 01:47:23 +00:00
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FEATURE COMMANDS
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================
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2019-01-17 15:27:50 +00:00
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tools: bpftool: add probes for a network device
bpftool gained support for probing the current system in order to see
what program and map types, and what helpers are available on that
system. This patch adds the possibility to pass an interface index to
libbpf (and hence to the kernel) when trying to load the programs or to
create the maps, in order to see what items a given network device can
support.
A new keyword "dev <ifname>" can be used as an alternative to "kernel"
to indicate that the given device should be tested. If no target ("dev"
or "kernel") is specified bpftool defaults to probing the kernel.
Sample output:
# bpftool -p feature probe dev lo
{
"syscall_config": {
"have_bpf_syscall": true
},
"program_types": {
"have_sched_cls_prog_type": false,
"have_xdp_prog_type": false
},
...
}
As the target is a network device, /proc/ parameters and kernel
configuration are NOT dumped. Availability of the bpf() syscall is
still probed, so we can return early if that syscall is not usable
(since there is no point in attempting the remaining probes in this
case).
Among the program types, only the ones that can be offloaded are probed.
All map types are probed, as there is no specific rule telling which one
could or could not be supported by a device in the future. All helpers
are probed (but only for offload-able program types).
Caveat: as bpftool does not attempt to attach programs to the device at
the moment, probes do not entirely reflect what the device accepts:
typically, for Netronome's nfp, results will announce that TC cls
offload is available even if support has been deactivated (with e.g.
ethtool -K eth1 hw-tc-offload off).
v2:
- All helpers are probed, whereas previous version would only probe the
ones compatible with an offload-able program type. This is because we
do not keep a default compatible program type for each helper anymore.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:57 +00:00
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| **bpftool** **feature probe** [*COMPONENT*] [**macros** [**prefix** *PREFIX*]]
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2019-01-17 15:27:50 +00:00
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| **bpftool** **feature help**
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tools: bpftool: add probes for a network device
bpftool gained support for probing the current system in order to see
what program and map types, and what helpers are available on that
system. This patch adds the possibility to pass an interface index to
libbpf (and hence to the kernel) when trying to load the programs or to
create the maps, in order to see what items a given network device can
support.
A new keyword "dev <ifname>" can be used as an alternative to "kernel"
to indicate that the given device should be tested. If no target ("dev"
or "kernel") is specified bpftool defaults to probing the kernel.
Sample output:
# bpftool -p feature probe dev lo
{
"syscall_config": {
"have_bpf_syscall": true
},
"program_types": {
"have_sched_cls_prog_type": false,
"have_xdp_prog_type": false
},
...
}
As the target is a network device, /proc/ parameters and kernel
configuration are NOT dumped. Availability of the bpf() syscall is
still probed, so we can return early if that syscall is not usable
(since there is no point in attempting the remaining probes in this
case).
Among the program types, only the ones that can be offloaded are probed.
All map types are probed, as there is no specific rule telling which one
could or could not be supported by a device in the future. All helpers
are probed (but only for offload-able program types).
Caveat: as bpftool does not attempt to attach programs to the device at
the moment, probes do not entirely reflect what the device accepts:
typically, for Netronome's nfp, results will announce that TC cls
offload is available even if support has been deactivated (with e.g.
ethtool -K eth1 hw-tc-offload off).
v2:
- All helpers are probed, whereas previous version would only probe the
ones compatible with an offload-able program type. This is because we
do not keep a default compatible program type for each helper anymore.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:57 +00:00
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| *COMPONENT* := { **kernel** | **dev** *NAME* }
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2019-01-17 15:27:50 +00:00
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DESCRIPTION
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===========
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tools: bpftool: add C-style "#define" output for probes
Make bpftool able to dump a subset of the parameters collected by
probing the system as a listing of C-style #define macros, so that
external projects can reuse the result of this probing and build
BPF-based project in accordance with the features available on the
system.
The new "macros" keyword is used to select this output. An additional
"prefix" keyword is added so that users can select a custom prefix for
macro names, in order to avoid any namespace conflict.
Sample output:
# bpftool feature probe kernel macros prefix FOO_
/*** System call availability ***/
#define FOO_HAVE_BPF_SYSCALL
/*** eBPF program types ***/
#define FOO_HAVE_SOCKET_FILTER_PROG_TYPE
#define FOO_HAVE_KPROBE_PROG_TYPE
#define FOO_HAVE_SCHED_CLS_PROG_TYPE
...
/*** eBPF map types ***/
#define FOO_HAVE_HASH_MAP_TYPE
#define FOO_HAVE_ARRAY_MAP_TYPE
#define FOO_HAVE_PROG_ARRAY_MAP_TYPE
...
/*** eBPF helper functions ***/
/*
* Use FOO_HAVE_PROG_TYPE_HELPER(prog_type_name, helper_name)
* to determine if <helper_name> is available for <prog_type_name>,
* e.g.
* #if FOO_HAVE_PROG_TYPE_HELPER(xdp, bpf_redirect)
* // do stuff with this helper
* #elif
* // use a workaround
* #endif
*/
#define FOO_HAVE_PROG_TYPE_HELPER(prog_type, helper) \
FOO_BPF__PROG_TYPE_ ## prog_type ## __HELPER_ ## helper
...
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_probe_read 0
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_ktime_get_ns 1
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_trace_printk 1
...
v3:
- Change output for helpers again: add a
HAVE_PROG_TYPE_HELPER(type, helper) macro that can be used to tell
if <helper> is available for program <type>.
v2:
- #define-based output added as a distinct patch.
- "HAVE_" prefix appended to macro names.
- Output limited to bpf() syscall availability, BPF prog and map types,
helper functions. In this version kernel config options, procfs
parameter or kernel version are intentionally left aside.
- Following the change on helper probes, format for helper probes in
this output style has changed (now a list of compatible program
types).
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:56 +00:00
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**bpftool feature probe** [**kernel**] [**macros** [**prefix** *PREFIX*]]
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2019-01-17 15:27:50 +00:00
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Probe the running kernel and dump a number of eBPF-related
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tools: bpftool: add probes for a network device
bpftool gained support for probing the current system in order to see
what program and map types, and what helpers are available on that
system. This patch adds the possibility to pass an interface index to
libbpf (and hence to the kernel) when trying to load the programs or to
create the maps, in order to see what items a given network device can
support.
A new keyword "dev <ifname>" can be used as an alternative to "kernel"
to indicate that the given device should be tested. If no target ("dev"
or "kernel") is specified bpftool defaults to probing the kernel.
Sample output:
# bpftool -p feature probe dev lo
{
"syscall_config": {
"have_bpf_syscall": true
},
"program_types": {
"have_sched_cls_prog_type": false,
"have_xdp_prog_type": false
},
...
}
As the target is a network device, /proc/ parameters and kernel
configuration are NOT dumped. Availability of the bpf() syscall is
still probed, so we can return early if that syscall is not usable
(since there is no point in attempting the remaining probes in this
case).
Among the program types, only the ones that can be offloaded are probed.
All map types are probed, as there is no specific rule telling which one
could or could not be supported by a device in the future. All helpers
are probed (but only for offload-able program types).
Caveat: as bpftool does not attempt to attach programs to the device at
the moment, probes do not entirely reflect what the device accepts:
typically, for Netronome's nfp, results will announce that TC cls
offload is available even if support has been deactivated (with e.g.
ethtool -K eth1 hw-tc-offload off).
v2:
- All helpers are probed, whereas previous version would only probe the
ones compatible with an offload-able program type. This is because we
do not keep a default compatible program type for each helper anymore.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:57 +00:00
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parameters, such as availability of the **bpf()** system call,
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JIT status, eBPF program types availability, eBPF helper
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functions availability, and more.
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2019-01-17 15:27:50 +00:00
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tools: bpftool: add C-style "#define" output for probes
Make bpftool able to dump a subset of the parameters collected by
probing the system as a listing of C-style #define macros, so that
external projects can reuse the result of this probing and build
BPF-based project in accordance with the features available on the
system.
The new "macros" keyword is used to select this output. An additional
"prefix" keyword is added so that users can select a custom prefix for
macro names, in order to avoid any namespace conflict.
Sample output:
# bpftool feature probe kernel macros prefix FOO_
/*** System call availability ***/
#define FOO_HAVE_BPF_SYSCALL
/*** eBPF program types ***/
#define FOO_HAVE_SOCKET_FILTER_PROG_TYPE
#define FOO_HAVE_KPROBE_PROG_TYPE
#define FOO_HAVE_SCHED_CLS_PROG_TYPE
...
/*** eBPF map types ***/
#define FOO_HAVE_HASH_MAP_TYPE
#define FOO_HAVE_ARRAY_MAP_TYPE
#define FOO_HAVE_PROG_ARRAY_MAP_TYPE
...
/*** eBPF helper functions ***/
/*
* Use FOO_HAVE_PROG_TYPE_HELPER(prog_type_name, helper_name)
* to determine if <helper_name> is available for <prog_type_name>,
* e.g.
* #if FOO_HAVE_PROG_TYPE_HELPER(xdp, bpf_redirect)
* // do stuff with this helper
* #elif
* // use a workaround
* #endif
*/
#define FOO_HAVE_PROG_TYPE_HELPER(prog_type, helper) \
FOO_BPF__PROG_TYPE_ ## prog_type ## __HELPER_ ## helper
...
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_probe_read 0
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_ktime_get_ns 1
#define FOO_BPF__PROG_TYPE_socket_filter__HELPER_bpf_trace_printk 1
...
v3:
- Change output for helpers again: add a
HAVE_PROG_TYPE_HELPER(type, helper) macro that can be used to tell
if <helper> is available for program <type>.
v2:
- #define-based output added as a distinct patch.
- "HAVE_" prefix appended to macro names.
- Output limited to bpf() syscall availability, BPF prog and map types,
helper functions. In this version kernel config options, procfs
parameter or kernel version are intentionally left aside.
- Following the change on helper probes, format for helper probes in
this output style has changed (now a list of compatible program
types).
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:56 +00:00
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If the **macros** keyword (but not the **-j** option) is
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passed, a subset of the output is dumped as a list of
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**#define** macros that are ready to be included in a C
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header file, for example. If, additionally, **prefix** is
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used to define a *PREFIX*, the provided string will be used
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as a prefix to the names of the macros: this can be used to
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avoid conflicts on macro names when including the output of
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this command as a header file.
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tools: bpftool: add probes for a network device
bpftool gained support for probing the current system in order to see
what program and map types, and what helpers are available on that
system. This patch adds the possibility to pass an interface index to
libbpf (and hence to the kernel) when trying to load the programs or to
create the maps, in order to see what items a given network device can
support.
A new keyword "dev <ifname>" can be used as an alternative to "kernel"
to indicate that the given device should be tested. If no target ("dev"
or "kernel") is specified bpftool defaults to probing the kernel.
Sample output:
# bpftool -p feature probe dev lo
{
"syscall_config": {
"have_bpf_syscall": true
},
"program_types": {
"have_sched_cls_prog_type": false,
"have_xdp_prog_type": false
},
...
}
As the target is a network device, /proc/ parameters and kernel
configuration are NOT dumped. Availability of the bpf() syscall is
still probed, so we can return early if that syscall is not usable
(since there is no point in attempting the remaining probes in this
case).
Among the program types, only the ones that can be offloaded are probed.
All map types are probed, as there is no specific rule telling which one
could or could not be supported by a device in the future. All helpers
are probed (but only for offload-able program types).
Caveat: as bpftool does not attempt to attach programs to the device at
the moment, probes do not entirely reflect what the device accepts:
typically, for Netronome's nfp, results will announce that TC cls
offload is available even if support has been deactivated (with e.g.
ethtool -K eth1 hw-tc-offload off).
v2:
- All helpers are probed, whereas previous version would only probe the
ones compatible with an offload-able program type. This is because we
do not keep a default compatible program type for each helper anymore.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:57 +00:00
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Keyword **kernel** can be omitted. If no probe target is
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specified, probing the kernel is the default behaviour.
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2019-01-17 15:27:50 +00:00
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tools: bpftool: add probes for eBPF helper functions
Similarly to what was done for program types and map types, add a set of
probes to test the availability of the different eBPF helper functions
on the current system.
For each known program type, all known helpers are tested, in order to
establish a compatibility matrix. Output is provided as a set of lists
of available helpers, one per program type.
Sample output:
# bpftool feature probe kernel
...
Scanning eBPF helper functions...
eBPF helpers supported for program type socket_filter:
- bpf_map_lookup_elem
- bpf_map_update_elem
- bpf_map_delete_elem
...
eBPF helpers supported for program type kprobe:
- bpf_map_lookup_elem
- bpf_map_update_elem
- bpf_map_delete_elem
...
# bpftool --json --pretty feature probe kernel
{
...
"helpers": {
"socket_filter_available_helpers": ["bpf_map_lookup_elem", \
"bpf_map_update_elem","bpf_map_delete_elem", ...
],
"kprobe_available_helpers": ["bpf_map_lookup_elem", \
"bpf_map_update_elem","bpf_map_delete_elem", ...
],
...
}
}
v5:
- In libbpf.map, move global symbol to the new LIBBPF_0.0.2 section.
v4:
- Use "enum bpf_func_id" instead of "__u32" in bpf_probe_helper()
declaration for the type of the argument used to pass the id of
the helper to probe.
- Undef BPF_HELPER_MAKE_ENTRY after using it.
v3:
- Do not pass kernel version from bpftool to libbpf probes (kernel
version for testing program with kprobes is retrieved directly from
libbpf).
- Dump one list of available helpers per program type (instead of one
list of compatible program types per helper).
v2:
- Move probes from bpftool to libbpf.
- Test all program types for each helper, print a list of working prog
types for each helper.
- Fall back on include/uapi/linux/bpf.h for names and ids of helpers.
- Remove C-style macros output from this patch.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:55 +00:00
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Note that when probed, some eBPF helpers (e.g.
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**bpf_trace_printk**\ () or **bpf_probe_write_user**\ ()) may
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print warnings to kernel logs.
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tools: bpftool: add probes for a network device
bpftool gained support for probing the current system in order to see
what program and map types, and what helpers are available on that
system. This patch adds the possibility to pass an interface index to
libbpf (and hence to the kernel) when trying to load the programs or to
create the maps, in order to see what items a given network device can
support.
A new keyword "dev <ifname>" can be used as an alternative to "kernel"
to indicate that the given device should be tested. If no target ("dev"
or "kernel") is specified bpftool defaults to probing the kernel.
Sample output:
# bpftool -p feature probe dev lo
{
"syscall_config": {
"have_bpf_syscall": true
},
"program_types": {
"have_sched_cls_prog_type": false,
"have_xdp_prog_type": false
},
...
}
As the target is a network device, /proc/ parameters and kernel
configuration are NOT dumped. Availability of the bpf() syscall is
still probed, so we can return early if that syscall is not usable
(since there is no point in attempting the remaining probes in this
case).
Among the program types, only the ones that can be offloaded are probed.
All map types are probed, as there is no specific rule telling which one
could or could not be supported by a device in the future. All helpers
are probed (but only for offload-able program types).
Caveat: as bpftool does not attempt to attach programs to the device at
the moment, probes do not entirely reflect what the device accepts:
typically, for Netronome's nfp, results will announce that TC cls
offload is available even if support has been deactivated (with e.g.
ethtool -K eth1 hw-tc-offload off).
v2:
- All helpers are probed, whereas previous version would only probe the
ones compatible with an offload-able program type. This is because we
do not keep a default compatible program type for each helper anymore.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-17 15:27:57 +00:00
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**bpftool feature probe dev** *NAME* [**macros** [**prefix** *PREFIX*]]
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Probe network device for supported eBPF features and dump
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results to the console.
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The two keywords **macros** and **prefix** have the same
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role as when probing the kernel.
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2019-01-17 15:27:50 +00:00
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**bpftool feature help**
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Print short help message.
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OPTIONS
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=======
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-h, --help
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Print short generic help message (similar to **bpftool help**).
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-v, --version
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Print version number (similar to **bpftool version**).
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-j, --json
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Generate JSON output. For commands that cannot produce JSON, this
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option has no effect.
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-p, --pretty
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Generate human-readable JSON output. Implies **-j**.
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SEE ALSO
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========
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**bpf**\ (2),
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**bpf-helpers**\ (7),
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**bpftool**\ (8),
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**bpftool-prog**\ (8),
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**bpftool-map**\ (8),
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**bpftool-cgroup**\ (8),
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**bpftool-net**\ (8),
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**bpftool-perf**\ (8)
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