wireguard-linux/tools/bpf/bpftool/Documentation, branch jd/unified-crypt-queue

bpftool: Add struct_ops support

2020-03-20T14:51:35Z

This patch adds struct_ops support to the bpftool. To recap a bit on the recent bpf_struct_ops feature on the kernel side: It currently supports "struct tcp_congestion_ops" to be implemented in bpf. At a high level, bpf_struct_ops is struct_ops map populated with a number of bpf progs. bpf_struct_ops currently supports the "struct tcp_congestion_ops". However, the bpf_struct_ops design is generic enough that other kernel struct ops can be supported in the future. Although struct_ops is map+progs at a high lever, there are differences in details. For example, 1) After registering a struct_ops, the struct_ops is held by the kernel subsystem (e.g. tcp-cc). Thus, there is no need to pin a struct_ops map or its progs in order to keep them around. 2) To iterate all struct_ops in a system, it iterates all maps in type BPF_MAP_TYPE_STRUCT_OPS. BPF_MAP_TYPE_STRUCT_OPS is the current usual filter. In the future, it may need to filter by other struct_ops specific properties. e.g. filter by tcp_congestion_ops or other kernel subsystem ops in the future. 3) struct_ops requires the running kernel having BTF info. That allows more flexibility in handling other kernel structs. e.g. it can always dump the latest bpf_map_info. 4) Also, "struct_ops" command is not intended to repeat all features already provided by "map" or "prog". For example, if there really is a need to pin the struct_ops map, the user can use the "map" cmd to do that. While the first attempt was to reuse parts from map/prog.c, it ended up not a lot to share. The only obvious item is the map_parse_fds() but that still requires modifications to accommodate struct_ops map specific filtering (for the immediate and the future needs). Together with the earlier mentioned differences, it is better to part away from map/prog.c. The initial set of subcmds are, register, unregister, show, and dump. For register, it registers all struct_ops maps that can be found in an obj file. Option can be added in the future to specify a particular struct_ops map. Also, the common bpf_tcp_cc is stateless (e.g. bpf_cubic.c and bpf_dctcp.c). The "reuse map" feature is not implemented in this patch and it can be considered later also. For other subcmds, please see the man doc for details. A sample output of dump: [root@arch-fb-vm1 bpf]# bpftool struct_ops dump name cubic [{ "bpf_map_info": { "type": 26, "id": 64, "key_size": 4, "value_size": 256, "max_entries": 1, "map_flags": 0, "name": "cubic", "ifindex": 0, "btf_vmlinux_value_type_id": 18452, "netns_dev": 0, "netns_ino": 0, "btf_id": 52, "btf_key_type_id": 0, "btf_value_type_id": 0 } },{ "bpf_struct_ops_tcp_congestion_ops": { "refcnt": { "refs": { "counter": 1 } }, "state": "BPF_STRUCT_OPS_STATE_INUSE", "data": { "list": { "next": 0, "prev": 0 }, "key": 0, "flags": 0, "init": "void (struct sock *) bictcp_init/prog_id:138", "release": "void (struct sock *) 0", "ssthresh": "u32 (struct sock *) bictcp_recalc_ssthresh/prog_id:141", "cong_avoid": "void (struct sock *, u32, u32) bictcp_cong_avoid/prog_id:140", "set_state": "void (struct sock *, u8) bictcp_state/prog_id:142", "cwnd_event": "void (struct sock *, enum tcp_ca_event) bictcp_cwnd_event/prog_id:139", "in_ack_event": "void (struct sock *, u32) 0", "undo_cwnd": "u32 (struct sock *) tcp_reno_undo_cwnd/prog_id:144", "pkts_acked": "void (struct sock *, const struct ack_sample *) bictcp_acked/prog_id:143", "min_tso_segs": "u32 (struct sock *) 0", "sndbuf_expand": "u32 (struct sock *) 0", "cong_control": "void (struct sock *, const struct rate_sample *) 0", "get_info": "size_t (struct sock *, u32, int *, union tcp_cc_info *) 0", "name": "bpf_cubic", "owner": 0 } } } ] Signed-off-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200318171656.129650-1-kafai@fb.com

bpftool: Documentation for bpftool prog profile

2020-03-09T23:04:07Z

Add documentation for the new bpftool prog profile command. Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200309173218.2739965-3-songliubraving@fb.com

bpftool: Update documentation of "bpftool feature" command

2020-02-26T17:34:34Z

Update documentation of "bpftool feature" command with information about new arguments: "full". Signed-off-by: Michal Rostecki Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20200226165941.6379-4-mrostecki@opensuse.org

bpftool: Support struct_ops, tracing, ext prog types

2020-02-26T15:40:53Z

Add support for prog types that were added to kernel but not present in bpftool yet: struct_ops, tracing, ext prog types and corresponding section names. Before: # bpftool p l ... 184: type 26 name test_subprog3 tag dda135a7dc0daf54 gpl loaded_at 2020-02-25T13:28:33-0800 uid 0 xlated 112B jited 103B memlock 4096B map_ids 136 btf_id 85 185: type 28 name new_get_skb_len tag d2de5b87d8e5dc49 gpl loaded_at 2020-02-25T13:28:33-0800 uid 0 xlated 72B jited 69B memlock 4096B map_ids 136 btf_id 85 After: # bpftool p l ... 184: tracing name test_subprog3 tag dda135a7dc0daf54 gpl loaded_at 2020-02-25T13:28:33-0800 uid 0 xlated 112B jited 103B memlock 4096B map_ids 136 btf_id 85 185: ext name new_get_skb_len tag d2de5b87d8e5dc49 gpl loaded_at 2020-02-25T13:28:33-0800 uid 0 xlated 72B jited 69B memlock 4096B map_ids 136 btf_id 85 Signed-off-by: Andrey Ignatov Signed-off-by: Daniel Borkmann Reviewed-by: Quentin Monnet Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20200225223441.689109-1-rdna@fb.com

bpftool: Use consistent include paths for libbpf

2020-01-21T00:37:45Z

Fix bpftool to include libbpf header files with the bpf/ prefix, to be consistent with external users of the library. Also ensure that all includes of exported libbpf header files (those that are exported on 'make install' of the library) use bracketed includes instead of quoted. To make sure no new files are introduced that doesn't include the bpf/ prefix in its include, remove tools/lib/bpf from the include path entirely, and use tools/lib instead. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157952560684.1683545.4765181397974997027.stgit@toke.dk

bpftool: Work-around rst2man conversion bug

2019-12-19T01:03:52Z

Work-around what appears to be a bug in rst2man convertion tool, used to create man pages out of reStructureText-formatted documents. If text line starts with dot, rst2man will put it in resulting man file verbatim. This seems to cause man tool to interpret it as a directive/command (e.g., `.bs`), and subsequently not render entire line because it's unrecognized one. Enclose '.xxx' words in extra formatting to work around. Fixes: cb21ac588546 ("bpftool: Add gen subcommand manpage") Reported-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song

bpftool: Add gen subcommand manpage

2019-12-18T06:16:36Z

Add bpftool-gen.rst describing skeleton on the high level. Also include a small, but complete, example BPF app (BPF side, userspace side, generated skeleton) in example section to demonstrate skeleton API and its usage. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20191218052552.2915188-4-andriin@fb.com

bpftool: Match maps by name

2019-12-15T17:03:18Z

This patch implements lookup by name for maps and changes the behavior of lookups by tag to be consistent with prog subcommands. Similarly to program subcommands, the show and dump commands will return all maps with the given name (or tag), whereas other commands will error out if several maps have the same name (resp. tag). When a map has BTF info, it is dumped in JSON with available BTF info. This patch requires that all matched maps have BTF info before switching the output format to JSON. Signed-off-by: Paul Chaignon Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/8de1c9f273860b3ea1680502928f4da2336b853e.1576263640.git.paul.chaignon@gmail.com

bpftool: Match programs by name

2019-12-15T17:03:18Z

When working with frequently modified BPF programs, both the ID and the tag may change. bpftool currently doesn't provide a "stable" way to match such programs. This patch implements lookup by name for programs. The show and dump commands will return all programs with the given name, whereas other commands will error out if several programs have the same name. Signed-off-by: Paul Chaignon Signed-off-by: Alexei Starovoitov Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/b5fc1a5dcfaeb5f16fc80295cdaa606dd2d91534.1576263640.git.paul.chaignon@gmail.com

bpftool: Match several programs with same tag

2019-12-15T17:03:18Z

When several BPF programs have the same tag, bpftool matches only the first (in ID order). This patch changes that behavior such that dump and show commands return all matched programs. Commands that require a single program (e.g., pin and attach) will error out if given a tag that matches several. bpftool prog dump will also error out if file or visual are given and several programs have the given tag. In the case of the dump command, a program header is added before each dump only if the tag matches several programs; this patch doesn't change the output if a single program matches. The output when several programs match thus looks as follows. $ ./bpftool prog dump xlated tag 6deef7357e7b4530 3: cgroup_skb tag 6deef7357e7b4530 gpl 0: (bf) r6 = r1 [...] 7: (95) exit 4: cgroup_skb tag 6deef7357e7b4530 gpl 0: (bf) r6 = r1 [...] 7: (95) exit Signed-off-by: Paul Chaignon Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/fb1fe943202659a69cd21dd5b907c205af1e1e22.1576263640.git.paul.chaignon@gmail.com