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Message-ID: <20200509175920.2477247-1-yhs@fb.com>
Date: Sat, 9 May 2020 10:59:20 -0700
From: Yonghong Song <yhs@...com>
To: Andrii Nakryiko <andriin@...com>, <bpf@...r.kernel.org>,
Martin KaFai Lau <kafai@...com>, <netdev@...r.kernel.org>
CC: Alexei Starovoitov <ast@...com>,
Daniel Borkmann <daniel@...earbox.net>, <kernel-team@...com>
Subject: [PATCH bpf-next v4 18/21] tools/bpftool: add bpf_iter support for bptool
Currently, only one command is supported
bpftool iter pin <bpf_prog.o> <path>
It will pin the trace/iter bpf program in
the object file <bpf_prog.o> to the <path>
where <path> should be on a bpffs mount.
For example,
$ bpftool iter pin ./bpf_iter_ipv6_route.o \
/sys/fs/bpf/my_route
User can then do a `cat` to print out the results:
$ cat /sys/fs/bpf/my_route
fe800000000000000000000000000000 40 00000000000000000000000000000000 ...
00000000000000000000000000000000 00 00000000000000000000000000000000 ...
00000000000000000000000000000001 80 00000000000000000000000000000000 ...
fe800000000000008c0162fffebdfd57 80 00000000000000000000000000000000 ...
ff000000000000000000000000000000 08 00000000000000000000000000000000 ...
00000000000000000000000000000000 00 00000000000000000000000000000000 ...
The implementation for ipv6_route iterator is in one of subsequent
patches.
This patch also added BPF_LINK_TYPE_ITER to link query.
In the future, we may add additional parameters to pin command
by parameterizing the bpf iterator. For example, a map_id or pid
may be added to let bpf program only traverses a single map or task,
similar to kernel seq_file single_open().
We may also add introspection command for targets/iterators by
leveraging the bpf_iter itself.
Signed-off-by: Yonghong Song <yhs@...com>
---
.../bpftool/Documentation/bpftool-iter.rst | 83 +++++++++++++++++
tools/bpf/bpftool/bash-completion/bpftool | 13 +++
tools/bpf/bpftool/iter.c | 88 +++++++++++++++++++
tools/bpf/bpftool/link.c | 1 +
tools/bpf/bpftool/main.c | 3 +-
tools/bpf/bpftool/main.h | 1 +
6 files changed, 188 insertions(+), 1 deletion(-)
create mode 100644 tools/bpf/bpftool/Documentation/bpftool-iter.rst
create mode 100644 tools/bpf/bpftool/iter.c
diff --git a/tools/bpf/bpftool/Documentation/bpftool-iter.rst b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
new file mode 100644
index 000000000000..13b173d93890
--- /dev/null
+++ b/tools/bpf/bpftool/Documentation/bpftool-iter.rst
@@ -0,0 +1,83 @@
+============
+bpftool-iter
+============
+-------------------------------------------------------------------------------
+tool to create BPF iterators
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+ **bpftool** [*OPTIONS*] **iter** *COMMAND*
+
+ *COMMANDS* := { **pin** | **help** }
+
+ITER COMMANDS
+===================
+
+| **bpftool** **iter pin** *OBJ* *PATH*
+| **bpftool** **iter help**
+|
+| *OBJ* := /a/file/of/bpf_iter_target.o
+
+
+DESCRIPTION
+===========
+ **bpftool iter pin** *OBJ* *PATH*
+ A bpf iterator combines a kernel iterating of
+ particular kernel data (e.g., tasks, bpf_maps, etc.)
+ and a bpf program called for each kernel data object
+ (e.g., one task, one bpf_map, etc.). User space can
+ *read* kernel iterator output through *read()* syscall.
+
+ The *pin* command creates a bpf iterator from *OBJ*,
+ and pin it to *PATH*. The *PATH* should be located
+ in *bpffs* mount. It must not contain a dot
+ character ('.'), which is reserved for future extensions
+ of *bpffs*.
+
+ User can then *cat PATH* to see the bpf iterator output.
+
+ **bpftool iter help**
+ Print short help message.
+
+OPTIONS
+=======
+ -h, --help
+ Print short generic help message (similar to **bpftool help**).
+
+ -V, --version
+ Print version number (similar to **bpftool version**).
+
+ -d, --debug
+ Print all logs available, even debug-level information. This
+ includes logs from libbpf as well as from the verifier, when
+ attempting to load programs.
+
+EXAMPLES
+========
+**# bpftool iter pin bpf_iter_netlink.o /sys/fs/bpf/my_netlink**
+
+::
+
+ Create a file-based bpf iterator from bpf_iter_netlink.o and pin it
+ to /sys/fs/bpf/my_netlink
+
+
+SEE ALSO
+========
+ **bpf**\ (2),
+ **bpf-helpers**\ (7),
+ **bpftool**\ (8),
+ **bpftool-prog**\ (8),
+ **bpftool-map**\ (8),
+ **bpftool-link**\ (8),
+ **bpftool-cgroup**\ (8),
+ **bpftool-feature**\ (8),
+ **bpftool-net**\ (8),
+ **bpftool-perf**\ (8),
+ **bpftool-btf**\ (8)
+ **bpftool-gen**\ (8)
+ **bpftool-struct_ops**\ (8)
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index fc989ead7313..9f0f20e73b87 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -610,6 +610,19 @@ _bpftool()
;;
esac
;;
+ iter)
+ case $command in
+ pin)
+ _filedir
+ return 0
+ ;;
+ *)
+ [[ $prev == $object ]] && \
+ COMPREPLY=( $( compgen -W 'pin help' \
+ -- "$cur" ) )
+ ;;
+ esac
+ ;;
map)
local MAP_TYPE='id pinned name'
case $command in
diff --git a/tools/bpf/bpftool/iter.c b/tools/bpf/bpftool/iter.c
new file mode 100644
index 000000000000..eb5987a0c3b6
--- /dev/null
+++ b/tools/bpf/bpftool/iter.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright (C) 2020 Facebook
+
+#define _GNU_SOURCE
+#include <linux/err.h>
+#include <bpf/libbpf.h>
+
+#include "main.h"
+
+static int do_pin(int argc, char **argv)
+{
+ const char *objfile, *path;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ struct bpf_link *link;
+ int err;
+
+ if (!REQ_ARGS(2))
+ usage();
+
+ objfile = GET_ARG();
+ path = GET_ARG();
+
+ obj = bpf_object__open(objfile);
+ if (IS_ERR(obj)) {
+ p_err("can't open objfile %s", objfile);
+ return -1;
+ }
+
+ err = bpf_object__load(obj);
+ if (err) {
+ p_err("can't load objfile %s", objfile);
+ goto close_obj;
+ }
+
+ prog = bpf_program__next(NULL, obj);
+ if (!prog) {
+ p_err("can't find bpf program in objfile %s", objfile);
+ goto close_obj;
+ }
+
+ link = bpf_program__attach_iter(prog, NULL);
+ if (IS_ERR(link)) {
+ err = PTR_ERR(link);
+ p_err("attach_iter failed for program %s",
+ bpf_program__name(prog));
+ goto close_obj;
+ }
+
+ err = mount_bpffs_for_pin(path);
+ if (err)
+ goto close_link;
+
+ err = bpf_link__pin(link, path);
+ if (err) {
+ p_err("pin_iter failed for program %s to path %s",
+ bpf_program__name(prog), path);
+ goto close_link;
+ }
+
+close_link:
+ bpf_link__destroy(link);
+close_obj:
+ bpf_object__close(obj);
+ return err;
+}
+
+static int do_help(int argc, char **argv)
+{
+ fprintf(stderr,
+ "Usage: %s %s pin OBJ PATH\n"
+ " %s %s help\n"
+ "\n",
+ bin_name, argv[-2], bin_name, argv[-2]);
+
+ return 0;
+}
+
+static const struct cmd cmds[] = {
+ { "help", do_help },
+ { "pin", do_pin },
+ { 0 }
+};
+
+int do_iter(int argc, char **argv)
+{
+ return cmd_select(cmds, argc, argv, do_help);
+}
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index adc7dc431ed8..b6a0b35c78ae 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -16,6 +16,7 @@ static const char * const link_type_name[] = {
[BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
[BPF_LINK_TYPE_TRACING] = "tracing",
[BPF_LINK_TYPE_CGROUP] = "cgroup",
+ [BPF_LINK_TYPE_ITER] = "iter",
};
static int link_parse_fd(int *argc, char ***argv)
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 1413a154806e..46bd716a9d86 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -59,7 +59,7 @@ static int do_help(int argc, char **argv)
" %s batch file FILE\n"
" %s version\n"
"\n"
- " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops }\n"
+ " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
" " HELP_SPEC_OPTIONS "\n"
"",
bin_name, bin_name, bin_name);
@@ -224,6 +224,7 @@ static const struct cmd cmds[] = {
{ "btf", do_btf },
{ "gen", do_gen },
{ "struct_ops", do_struct_ops },
+ { "iter", do_iter },
{ "version", do_version },
{ 0 }
};
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 9b1fb81a8331..a41cefabccaf 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -199,6 +199,7 @@ int do_feature(int argc, char **argv);
int do_btf(int argc, char **argv);
int do_gen(int argc, char **argv);
int do_struct_ops(int argc, char **argv);
+int do_iter(int argc, char **argv);
int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
int prog_parse_fd(int *argc, char ***argv);
--
2.24.1
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