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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
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+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+============
+bpftool-iter
+============
+-------------------------------------------------------------------------------
+tool to create BPF iterators
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+.. include:: substitutions.rst
+
+SYNOPSIS
+========
+
+ **bpftool** [*OPTIONS*] **iter** *COMMAND*
+
+ *OPTIONS* := { |COMMON_OPTIONS| }
+
+ *COMMANDS* := { **pin** | **help** }
+
+ITER COMMANDS
+===================
+
+| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP*]
+| **bpftool** **iter help**
+|
+| *OBJ* := /a/file/of/bpf_iter_target.o
+| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
+
+DESCRIPTION
+===========
+ **bpftool iter pin** *OBJ* *PATH* [**map** *MAP*]
+ 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*.
+
+ Map element bpf iterator requires an additional parameter
+ *MAP* so bpf program can iterate over map elements for
+ that map. User can have a bpf program in kernel to run
+ with each map element, do checking, filtering, aggregation,
+ etc. without copying data to user space.
+
+ User can then *cat PATH* to see the bpf iterator output.
+
+ **bpftool iter help**
+ Print short help message.
+
+OPTIONS
+=======
+ .. include:: common_options.rst
+
+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
+
+**# bpftool iter pin bpf_iter_hashmap.o /sys/fs/bpf/my_hashmap map id 20**
+
+::
+
+ Create a file-based bpf iterator from bpf_iter_hashmap.o and map with
+ id 20, and pin it to /sys/fs/bpf/my_hashmap