- 30 Apr, 2018 3 commits
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Quentin Monnet authored
Some edits brought to the last iteration of BPF helper functions documentation introduced an error with RST formatting. As a result, most of one paragraph is rendered in bold text when only the name of a helper should be. Fix it, and fix formatting of another function name in the same paragraph. Fixes: c6b5fb86 ("bpf: add documentation for eBPF helpers (42-50)") Signed-off-by:
Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net>
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Alexei Starovoitov authored
tracepoints to bpf core were added as a way to provide introspection to bpf programs and maps, but after some time it became clear that this approach is inadequate, so prog_id, map_id and corresponding get_next_id, get_fd_by_id, get_info_by_fd, prog_query APIs were introduced and fully adopted by bpftool and other applications. The tracepoints in bpf core started to rot and causing syzbot warnings: WARNING: CPU: 0 PID: 3008 at kernel/trace/trace_event_perf.c:274 Kernel panic - not syncing: panic_on_warn set ... perf_trace_bpf_map_keyval+0x260/0xbd0 include/trace/events/bpf.h:228 trace_bpf_map_update_elem include/trace/events/bpf.h:274 [inline] map_update_elem kernel/bpf/syscall.c:597 [inline] SYSC_bpf kernel/bpf/syscall.c:1478 [inline] Hence this patch deletes tracepoints in bpf core. Reported-by:
Eric Biggers <ebiggers3@gmail.com> Reported-by:
syzbot <bot+a9dbb3c3e64b62536a4bc5ee7bbd4ca627566188@syzkaller.appspotmail.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Acked-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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Yonghong Song authored
Commit d5a00528 ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()") renamed a lot of syscall function sys_*() to __x64_sys_*(). This caused several kprobe based samples/bpf tests failing. This patch fixed the problem in bpf_load.c. For x86_64 architecture, function name __x64_sys_*() will be first used for kprobe event creation. If the creation is successful, it will be used. Otherwise, function name sys_*() will be used for kprobe event creation. Fixes: d5a00528 ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()") Signed-off-by:
Yonghong Song <yhs@fb.com> Signed-off-by:
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- 29 Apr, 2018 15 commits
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Teng Qin authored
Currently, the bpf_current_task_under_cgroup helper has a check where if the BPF program is running in_interrupt(), it will return -EINVAL. This prevents the helper to be used in many useful scenarios, particularly BPF programs attached to Perf Events. This commit removes the check. Tested a few NMI (Perf Event) and some softirq context, the helper returns the correct result. Signed-off-by:
Teng Qin <qinteng@fb.com> Signed-off-by:
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Alexei Starovoitov authored
Andrey Ignatov says: ==================== BPF helpers documentation in UAPI refers to kernel ctx structures when it has to refer to user visible ones. Fix it. ==================== Reviewed-by:
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Andrey Ignatov authored
The patch syncs bpf.h to tools/. Signed-off-by:
Andrey Ignatov <rdna@fb.com> Signed-off-by:
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Andrey Ignatov authored
Helpers may operate on two types of ctx structures: user visible ones (e.g. `struct bpf_sock_ops`) when used in user programs, and kernel ones (e.g. `struct bpf_sock_ops_kern`) in kernel implementation. UAPI documentation must refer to only user visible structures. The patch replaces references to `_kern` structures in BPF helpers description by corresponding user visible structures. Signed-off-by:
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Alexei Starovoitov authored
Yonghong Song says: ==================== Currently, stackmap and bpf_get_stackid helper are provided for bpf program to get the stack trace. This approach has a limitation though. If two stack traces have the same hash, only one will get stored in the stackmap table regardless of whether BPF_F_REUSE_STACKID is specified or not, so some stack traces may be missing from user perspective. This patch implements a new helper, bpf_get_stack, will send stack traces directly to bpf program. The bpf program is able to see all stack traces, and then can do in-kernel processing or send stack traces to user space through shared map or bpf_perf_event_output. Patches #1 and #2 implemented the core kernel support. Patch #3 removes two never-hit branches in verifier. Patches #4 and #5 are two verifier improves to make bpf programming easier. Patch #6 synced the new helper to tools headers. Patch #7 moved perf_event polling code and ksym lookup code from samples/bpf to tools/testing/selftests/bpf. Patch #8 added a verifier test in tools/bpf for new verifier change. Patches #9 and #10 added tests for raw tracepoint prog and tracepoint prog respectively. Changelogs: v8 -> v9: . make function perf_event_mmap (in trace_helpers.c) extern to decouple perf_event_mmap and perf_event_poller. . add jit enabled handling for kernel stack verification in Patch #9. Since we did not have a good way to verify jit enabled kernel stack, just return true if the kernel stack is not empty. . In path #9, using raw_syscalls/sys_enter instead of sched/sched_switch, removed calling cmd "task 1 dd if=/dev/zero of=/dev/null" which is left with dangling process after the program exited. v7 -> v8: . rebase on top of latest bpf-next . simplify BPF_ARSH dst_reg->smin_val/smax_value tracking . rewrite the description of bpf_get_stack() in uapi bpf.h based on new format. v6 -> v7: . do perf callchain buffer allocation inside the verifier. so if the prog->has_callchain_buf is set, it is guaranteed that the buffer has been allocated. . change condition "trace_nr <= skip" to "trace_nr < skip" so that for zero size buffer, return 0 instead of -EFAULT v5 -> v6: . after refining return register smax_value and umax_value for helpers bpf_get_stack and bpf_probe_read_str, bounds and var_off of the return register are further refined. . added missing commit message for tools header sync commit. . removed one unnecessary empty line. v4 -> v5: . relied on dst_reg->var_off to refine umin_val/umax_val in verifier handling BPF_ARSH value range tracking, suggested by Edward. v3 -> v4: . fixed a bug when meta ptr is set to NULL in check_func_arg. . introduced tnum_arshift and added detailed comments for the underlying implementation . avoided using VLA in tools/bpf test_progs. v2 -> v3: . used meta to track helper memory size argument . implemented range checking for ARSH in verifier . moved perf event polling and ksym related functions from samples/bpf to tools/bpf . added test to compare build id's between bpf_get_stackid and bpf_get_stack v1 -> v2: . fixed compilation error when CONFIG_PERF_EVENTS is not enabled ==================== Signed-off-by: -
Yonghong Song authored
The test_stacktrace_map and test_stacktrace_build_id are enhanced to call bpf_get_stack in the helper to get the stack trace as well. The stack traces from bpf_get_stack and bpf_get_stackid are compared to ensure that for the same stack as represented as the same hash, their ip addresses or build id's must be the same. Acked-by:
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Yonghong Song authored
The test attached a raw_tracepoint program to raw_syscalls/sys_enter. It tested to get stack for user space, kernel space and user space with build_id request. It also tested to get user and kernel stack into the same buffer with back-to-back bpf_get_stack helper calls. If jit is not enabled, the user space application will check to ensure that the kernel function for raw_tracepoint ___bpf_prog_run is part of the stack. If jit is enabled, we did not have a reliable way to verify the kernel stack, so just assume the kernel stack is good when the kernel stack size is greater than 0. Signed-off-by:
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Yonghong Song authored
The test_verifier already has a few ARSH test cases. This patch adds a new test case which takes advantage of newly improved verifier behavior for bpf_get_stack and ARSH. Signed-off-by:
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Yonghong Song authored
There is no functionality change in this patch. The common-purpose trace functions, including perf_event polling and ksym lookup, are moved from trace_output_user.c and bpf_load.c to selftests/bpf/trace_helpers.c so that these function can be reused later in selftests. Acked-by:
Alexei Starovoitov <ast@fb.com> Signed-off-by:
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Yonghong Song authored
The tools header file bpf.h is synced with kernel uapi bpf.h. The new helper is also added to bpf_helpers.h. Signed-off-by:
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Yonghong Song authored
When helpers like bpf_get_stack returns an int value and later on used for arithmetic computation, the LSH and ARSH operations are often required to get proper sign extension into 64-bit. For example, without this patch: 54: R0=inv(id=0,umax_value=800) 54: (bf) r8 = r0 55: R0=inv(id=0,umax_value=800) R8_w=inv(id=0,umax_value=800) 55: (67) r8 <<= 32 56: R8_w=inv(id=0,umax_value=3435973836800,var_off=(0x0; 0x3ff00000000)) 56: (c7) r8 s>>= 32 57: R8=inv(id=0) With this patch: 54: R0=inv(id=0,umax_value=800) 54: (bf) r8 = r0 55: R0=inv(id=0,umax_value=800) R8_w=inv(id=0,umax_value=800) 55: (67) r8 <<= 32 56: R8_w=inv(id=0,umax_value=3435973836800,var_off=(0x0; 0x3ff00000000)) 56: (c7) r8 s>>= 32 57: R8=inv(id=0, umax_value=800,var_off=(0x0; 0x3ff)) With better range of "R8", later on when "R8" is added to other register, e.g., a map pointer or scalar-value register, the better register range can be derived and verifier failure may be avoided. In our later example, ...... usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK); if (usize < 0) return 0; ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0); ...... Without improving ARSH value range tracking, the register representing "max_len - usize" will have smin_value equal to S64_MIN and will be rejected by verifier. Acked-by: -
Yonghong Song authored
In verifier function adjust_scalar_min_max_vals, when src_known is false and the opcode is BPF_LSH/BPF_RSH, early return will happen in the function. So remove the branch in handling BPF_LSH/BPF_RSH when src_known is false. Acked-by:
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Yonghong Song authored
The special property of return values for helpers bpf_get_stack and bpf_probe_read_str are captured in verifier. Both helpers return a negative error code or a length, which is equal to or smaller than the buffer size argument. This additional information in the verifier can avoid the condition such as "retval > bufsize" in the bpf program. For example, for the code blow, usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK); if (usize < 0 || usize > max_len) return 0; The verifier may have the following errors: 52: (85) call bpf_get_stack#65 R0=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R1_w=ctx(id=0,off=0,imm=0) R2_w=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R3_w=inv800 R4_w=inv256 R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R9_w=inv800 R10=fp0,call_-1 53: (bf) r8 = r0 54: (bf) r1 = r8 55: (67) r1 <<= 32 56: (bf) r2 = r1 57: (77) r2 >>= 32 58: (25) if r2 > 0x31f goto pc+33 R0=inv(id=0) R1=inv(id=0,smax_value=9223372032559808512, umax_value=18446744069414584320, var_off=(0x0; 0xffffffff00000000)) R2=inv(id=0,umax_value=799,var_off=(0x0; 0x3ff)) R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R8=inv(id=0) R9=inv800 R10=fp0,call_-1 59: (1f) r9 -= r8 60: (c7) r1 s>>= 32 61: (bf) r2 = r7 62: (0f) r2 += r1 math between map_value pointer and register with unbounded min value is not allowed The failure is due to llvm compiler optimization where register "r2", which is a copy of "r1", is tested for condition while later on "r1" is used for map_ptr operation. The verifier is not able to track such inst sequence effectively. Without the "usize > max_len" condition, there is no llvm optimization and the below generated code passed verifier: 52: (85) call bpf_get_stack#65 R0=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R1_w=ctx(id=0,off=0,imm=0) R2_w=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R3_w=inv800 R4_w=inv256 R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R9_w=inv800 R10=fp0,call_-1 53: (b7) r1 = 0 54: (bf) r8 = r0 55: (67) r8 <<= 32 56: (c7) r8 s>>= 32 57: (6d) if r1 s> r8 goto pc+24 R0=inv(id=0,umax_value=800,var_off=(0x0; 0x3ff)) R1=inv0 R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R8=inv(id=0,umax_value=800,var_off=(0x0; 0x3ff)) R9=inv800 R10=fp0,call_-1 58: (bf) r2 = r7 59: (0f) r2 += r8 60: (1f) r9 -= r8 61: (bf) r1 = r6 Acked-by: -
Yonghong Song authored
Currently, stackmap and bpf_get_stackid helper are provided for bpf program to get the stack trace. This approach has a limitation though. If two stack traces have the same hash, only one will get stored in the stackmap table, so some stack traces are missing from user perspective. This patch implements a new helper, bpf_get_stack, will send stack traces directly to bpf program. The bpf program is able to see all stack traces, and then can do in-kernel processing or send stack traces to user space through shared map or bpf_perf_event_output. Acked-by:
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Yonghong Song authored
This patch didn't incur functionality change. The function prototype got changed so that the same function can be reused later. Signed-off-by:
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- 27 Apr, 2018 2 commits
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Leo Yan authored
When CONFIG_BPF_JIT_ALWAYS_ON is enabled, kernel has limitation for bpf_jit_enable, so it has fixed value 1 and we cannot set it to 2 for JIT opcode dumping; this patch is to update the doc for it. Suggested-by:
Leo Yan <leo.yan@linaro.org> Signed-off-by:
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git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller authored
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-04-27 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Add extensive BPF helper description into include/uapi/linux/bpf.h and a new script bpf_helpers_doc.py which allows for generating a man page out of it. Thus, every helper in BPF now comes with proper function signature, detailed description and return code explanation, from Quentin. 2) Migrate the BPF collect metadata tunnel tests from BPF samples over to the BPF selftests and further extend them with v6 vxlan, geneve and ipip tests, simplify the ipip tests, improve documentation and convert to bpf_ntoh*() / bpf_hton*() api, from William. 3) Currently, helpers that expect ARG_PTR_TO_MAP_{KEY,VALUE} can only access stack and packet memory. Extend this to allow such helpers to also use map values, which enabled use cases where value from a first lookup can be directly used as a key for a second lookup, from Paul. 4) Add a new helper bpf_skb_get_xfrm_state() for tc BPF programs in order to retrieve XFRM state information containing SPI, peer address and reqid values, from Eyal. 5) Various optimizations in nfp driver's BPF JIT in order to turn ADD and SUB instructions with negative immediate into the opposite operation with a positive immediate such that nfp can better fit small immediates into instructions. Savings in instruction count up to 4% have been observed, from Jakub. 6) Add the BPF prog's gpl_compatible flag to struct bpf_prog_info and add support for dumping this through bpftool, from Jiri. 7) Move the BPF sockmap samples over into BPF selftests instead since sockmap was rather a series of tests than sample anyway and this way this can be run from automated bots, from John. 8) Follow-up fix for bpf_adjust_tail() helper in order to make it work with generic XDP, from Nikita. 9) Some follow-up cleanups to BTF, namely, removing unused defines from BTF uapi header and renaming 'name' struct btf_* members into name_off to make it more clear they are offsets into string section, from Martin. 10) Remove test_sock_addr from TEST_GEN_PROGS in BPF selftests since not run directly but invoked from test_sock_addr.sh, from Yonghong. 11) Remove redundant ret assignment in sample BPF loader, from Wang. 12) Add couple of missing files to BPF selftest's gitignore, from Anders. There are two trivial merge conflicts while pulling: 1) Remove samples/sockmap/Makefile since all sockmap tests have been moved to selftests. 2) Add both hunks from tools/testing/selftests/bpf/.gitignore to the file since git should ignore all of them. ==================== Signed-off-by:
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- 26 Apr, 2018 20 commits
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Wang Sheng-Hui authored
2 redundant ret assignments removed: * 'ret = 1' before the logic 'if (data_maps)', and if any errors jump to label 'done'. No 'ret = 1' needed before the error jump. * After the '/* load programs */' part, if everything goes well, then the BPF code will be loaded and 'ret' set to 0 by load_and_attach(). If something goes wrong, 'ret' set to none-O, the redundant 'ret = 0' after the for clause will make the error skipped. For example, if some BPF code cannot provide supported program types in ELF SEC("unknown"), the for clause will not call load_and_attach() to load the BPF code. 1 should be returned to callees instead of 0. Signed-off-by:Wang Sheng-Hui <shhuiw@foxmail.com> Signed-off-by:
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Daniel Borkmann authored
Quentin Monnet says: ==================== eBPF helper functions can be called from within eBPF programs to perform a variety of tasks that would be otherwise hard or impossible to do with eBPF itself. There is a growing number of such helper functions in the kernel, but documentation is scarce. The main user space header file does contain a short commented description of most helpers, but it is somewhat outdated and not complete. It is more a "cheat sheet" than a real documentation accessible to new eBPF developers. This commit attempts to improve the situation by replacing the existing overview for the helpers with a more developed description. Furthermore, a Python script is added to generate a manual page for eBPF helpers. The workflow is the following, and requires the rst2man utility: $ ./scripts/bpf_helpers_doc.py \ --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 $ man /tmp/bpf-helpers.7 The objective is to keep all documentation related to the helpers in a single place, and to be able to generate from here a manual page that could be packaged in the man-pages repository and shipped with most distributions. Additionally, parsing the prototypes of the helper functions could hopefully be reused, with a different Printer object, to generate header files needed in some eBPF-related projects. Regarding the description of each helper, it comprises several items: - The function prototype. - A description of the function and of its arguments (except for a couple of cases, when there are no arguments and the return value makes the function usage really obvious). - A description of return values (if not void). Additional items such as the list of compatible eBPF program and map types for each helper, Linux kernel version that introduced the helper, GPL-only restriction, and commit hash could be added in the future, but it was decided on the mailing list to leave them aside for now. For several helpers, descriptions are inspired (at times, nearly copied) from the commit logs introducing them in the kernel--Many thanks to their respective authors! Some sentences were also adapted from comments from the reviews, thanks to the reviewers as well. Descriptions were completed as much as possible, the objective being to have something easily accessible even for people just starting with eBPF. There is probably a bit more work to do in this direction for some helpers. Some RST formatting is used in the descriptions (not in function prototypes, to keep them readable, but the Python script provided in order to generate the RST for the manual page does add formatting to prototypes, to produce something pretty) to get "bold" and "italics" in manual pages. Hopefully, the descriptions in bpf.h file remains perfectly readable. Note that the few trailing white spaces are intentional, removing them would break paragraphs for rst2man. The descriptions should ideally be updated each time someone adds a new helper, or updates the behaviour (new socket option supported, ...) or the interface (new flags available, ...) of existing ones. To ease the review process, the documentation has been split into several patches. v3 -> v4: - Add a patch (#9) for newly added BPF helpers. - Add a patch (#10) to update UAPI bpf.h version under tools/. - Use SPDX tag in Python script. - Several fixes on man page header and footer, and helpers documentation. Please refer to individual patches for details. RFC v2 -> PATCH v3: Several fixes on man page header and footer, and helpers documentation. Please refer to individual patches for details. RFC v1 -> RFC v2: - Remove "For" (compatible program and map types), "Since" (minimal Linux kernel version required), "GPL only" sections and commit hashes for the helpers. - Add comment on top of the description list to explain how this documentation is supposed to be processed. - Update Python script accordingly (remove the same sections, and remove paragraphs on program types and GPL restrictions from man page header). - Split series into several patches. ==================== Signed-off-by: -
Quentin Monnet authored
Update tools/include/uapi/linux/bpf.h file in order to reflect the changes for BPF helper functions documentation introduced in previous commits. Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions: Helper from Nikita: - bpf_xdp_adjust_tail() Helper from Eyal: - bpf_skb_get_xfrm_state() v4: - New patch (helpers did not exist yet for previous versions). Cc: Nikita V. Shirokov <tehnerd@tehnerd.com> Cc: Eyal Birger <eyal.birger@gmail.com> Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by John: - bpf_redirect_map() - bpf_sk_redirect_map() - bpf_sock_map_update() - bpf_msg_redirect_map() - bpf_msg_apply_bytes() - bpf_msg_cork_bytes() - bpf_msg_pull_data() v4: - bpf_redirect_map(): Fix typos: "XDP_ABORT" changed to "XDP_ABORTED", "his" to "this". Also add a paragraph on performance improvement over bpf_redirect() helper. v3: - bpf_sk_redirect_map(): Improve description of BPF_F_INGRESS flag. - bpf_msg_redirect_map(): Improve description of BPF_F_INGRESS flag. - bpf_redirect_map(): Fix note on CPU redirection, not fully implemented for generic XDP but supported on native XDP. - bpf_msg_pull_data(): Clarify comment about invalidated verifier checks. Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions: Helpers from Lawrence: - bpf_setsockopt() - bpf_getsockopt() - bpf_sock_ops_cb_flags_set() Helpers from Yonghong: - bpf_perf_event_read_value() - bpf_perf_prog_read_value() Helper from Josef: - bpf_override_return() Helper from Andrey: - bpf_bind() v4: - bpf_perf_event_read_value(): State that this helper should be preferred over bpf_perf_event_read(). v3: - bpf_perf_event_read_value(): Fix time of selection for perf event type in description. Remove occurences of "cores" to avoid confusion with "CPU". - bpf_bind(): Remove last paragraph of description, which was off topic. Cc: Lawrence Brakmo <brakmo@fb.com> Cc: Yonghong Song <yhs@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Andrey Ignatov <rdna@fb.com> Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions: Helper from Kaixu: - bpf_perf_event_read() Helpers from Martin: - bpf_skb_under_cgroup() - bpf_xdp_adjust_head() Helpers from Sargun: - bpf_probe_write_user() - bpf_current_task_under_cgroup() Helper from Thomas: - bpf_skb_change_head() Helper from Gianluca: - bpf_probe_read_str() Helpers from Chenbo: - bpf_get_socket_cookie() - bpf_get_socket_uid() v4: - bpf_perf_event_read(): State that bpf_perf_event_read_value() should be preferred over this helper. - bpf_skb_change_head(): Clarify comment about invalidated verifier checks. - bpf_xdp_adjust_head(): Clarify comment about invalidated verifier checks. - bpf_probe_write_user(): Add that dst must be a valid user space address. - bpf_get_socket_cookie(): Improve description by making clearer that the cockie belongs to the socket, and state that it remains stable for the life of the socket. v3: - bpf_perf_event_read(): Fix time of selection for perf event type in description. Remove occurences of "cores" to avoid confusion with "CPU". Cc: Martin KaFai Lau <kafai@fb.com> Cc: Sargun Dhillon <sargun@sargun.me> Cc: Thomas Graf <tgraf@suug.ch> Cc: Gianluca Borello <g.borello@gmail.com> Cc: Chenbo Feng <fengc@google.com> Signed-off-by:
Martin KaFai Lau <kafai@fb.com> [for bpf_skb_under_cgroup(), bpf_xdp_adjust_head()] Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by Daniel: - bpf_get_hash_recalc() - bpf_skb_change_tail() - bpf_skb_pull_data() - bpf_csum_update() - bpf_set_hash_invalid() - bpf_get_numa_node_id() - bpf_set_hash() - bpf_skb_adjust_room() - bpf_xdp_adjust_meta() v4: - bpf_skb_change_tail(): Clarify comment about invalidated verifier checks. - bpf_skb_pull_data(): Clarify the motivation for using this helper or bpf_skb_load_bytes(), on non-linear buffers. Fix RST formatting for *skb*. Clarify comment about invalidated verifier checks. - bpf_csum_update(): Fix description of checksum (entire packet, not IP checksum). Fix a typo: "header" instead of "helper". - bpf_set_hash_invalid(): Mention bpf_get_hash_recalc(). - bpf_get_numa_node_id(): State that the helper is not restricted to programs attached to sockets. - bpf_skb_adjust_room(): Clarify comment about invalidated verifier checks. - bpf_xdp_adjust_meta(): Clarify comment about invalidated verifier checks. Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by Daniel: - bpf_get_prandom_u32() - bpf_get_smp_processor_id() - bpf_get_cgroup_classid() - bpf_get_route_realm() - bpf_skb_load_bytes() - bpf_csum_diff() - bpf_skb_get_tunnel_opt() - bpf_skb_set_tunnel_opt() - bpf_skb_change_proto() - bpf_skb_change_type() v4: - bpf_get_prandom_u32(): Warn that the prng is not cryptographically secure. - bpf_get_smp_processor_id(): Fix a typo (case). - bpf_get_cgroup_classid(): Clarify description. Add notes on the helper being limited to cgroup v1, and to egress path. - bpf_get_route_realm(): Add comparison with bpf_get_cgroup_classid(). Add a note about usage with TC and advantage of clsact. Fix a typo in return value ("sdb" instead of "skb"). - bpf_skb_load_bytes(): Make explicit loading large data loads it to the eBPF stack. - bpf_csum_diff(): Add a note on seed that can be cascaded. Link to bpf_l3|l4_csum_replace(). - bpf_skb_get_tunnel_opt(): Add a note about usage with "collect metadata" mode, and example of this with Geneve. - bpf_skb_set_tunnel_opt(): Add a link to bpf_skb_get_tunnel_opt() description. - bpf_skb_change_proto(): Mention that the main use case is NAT64. Clarify comment about invalidated verifier checks. v3: - bpf_get_prandom_u32(): Fix helper name :(. Add description, including a note on the internal random state. - bpf_get_smp_processor_id(): Add description, including a note on the processor id remaining stable during program run. - bpf_get_cgroup_classid(): State that CONFIG_CGROUP_NET_CLASSID is required to use the helper. Add a reference to related documentation. State that placing a task in net_cls controller disables cgroup-bpf. - bpf_get_route_realm(): State that CONFIG_CGROUP_NET_CLASSID is required to use this helper. - bpf_skb_load_bytes(): Fix comment on current use cases for the helper. Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: -
Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by Alexei: - bpf_get_current_pid_tgid() - bpf_get_current_uid_gid() - bpf_get_current_comm() - bpf_skb_vlan_push() - bpf_skb_vlan_pop() - bpf_skb_get_tunnel_key() - bpf_skb_set_tunnel_key() - bpf_redirect() - bpf_perf_event_output() - bpf_get_stackid() - bpf_get_current_task() v4: - bpf_redirect(): Fix typo: "XDP_ABORT" changed to "XDP_ABORTED". Add note on bpf_redirect_map() providing better performance. Replace "Save for" with "Except for". - bpf_skb_vlan_push(): Clarify comment about invalidated verifier checks. - bpf_skb_vlan_pop(): Clarify comment about invalidated verifier checks. - bpf_skb_get_tunnel_key(): Add notes on tunnel_id, "collect metadata" mode, and example tunneling protocols with which it can be used. - bpf_skb_set_tunnel_key(): Add a reference to the description of bpf_skb_get_tunnel_key(). - bpf_perf_event_output(): Specify that, and for what purpose, the helper can be used with programs attached to TC and XDP. v3: - bpf_skb_get_tunnel_key(): Change and improve description and example. - bpf_redirect(): Improve description of BPF_F_INGRESS flag. - bpf_perf_event_output(): Fix first sentence of description. Delete wrong statement on context being evaluated as a struct pt_reg. Remove the long yet incomplete example. - bpf_get_stackid(): Add a note about PERF_MAX_STACK_DEPTH being configurable. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by:
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Quentin Monnet authored
Add documentation for eBPF helper functions to bpf.h user header file. This documentation can be parsed with the Python script provided in another commit of the patch series, in order to provide a RST document that can later be converted into a man page. The objective is to make the documentation easily understandable and accessible to all eBPF developers, including beginners. This patch contains descriptions for the following helper functions, all written by Alexei: - bpf_map_lookup_elem() - bpf_map_update_elem() - bpf_map_delete_elem() - bpf_probe_read() - bpf_ktime_get_ns() - bpf_trace_printk() - bpf_skb_store_bytes() - bpf_l3_csum_replace() - bpf_l4_csum_replace() - bpf_tail_call() - bpf_clone_redirect() v4: - bpf_map_lookup_elem(): Add "const" qualifier for key. - bpf_map_update_elem(): Add "const" qualifier for key and value. - bpf_map_lookup_elem(): Add "const" qualifier for key. - bpf_skb_store_bytes(): Clarify comment about invalidated verifier checks. - bpf_l3_csum_replace(): Mention L3 instead of just IP, and add a note about bpf_csum_diff(). - bpf_l4_csum_replace(): Mention L4 instead of just TCP/UDP, and add a note about bpf_csum_diff(). - bpf_tail_call(): Bring minor edits to description. - bpf_clone_redirect(): Add a note about the relation with bpf_redirect(). Also clarify comment about invalidated verifier checks. v3: - bpf_map_lookup_elem(): Fix description of restrictions for flags related to the existence of the entry. - bpf_trace_printk(): State that trace_pipe can be configured. Fix return value in case an unknown format specifier is met. Add a note on kernel log notice when the helper is used. Edit example. - bpf_tail_call(): Improve comment on stack inheritance. - bpf_clone_redirect(): Improve description of BPF_F_INGRESS flag. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by:
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Quentin Monnet authored
Remove previous "overview" of eBPF helpers from user bpf.h header. Replace it by a comment explaining how to process the new documentation (to come in following patches) with a Python script to produce RST, then man page documentation. Also add the aforementioned Python script under scripts/. It is used to process include/uapi/linux/bpf.h and to extract helper descriptions, to turn it into a RST document that can further be processed with rst2man to produce a man page. The script takes one "--filename <path/to/file>" option. If the script is launched from scripts/ in the kernel root directory, it should be able to find the location of the header to parse, and "--filename <path/to/file>" is then optional. If it cannot find the file, then the option becomes mandatory. RST-formatted documentation is printed to standard output. Typical workflow for producing the final man page would be: $ ./scripts/bpf_helpers_doc.py \ --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 $ man /tmp/bpf-helpers.7 Note that the tool kernel-doc cannot be used to document eBPF helpers, whose signatures are not available directly in the header files (pre-processor directives are used to produce them at the beginning of the compilation process). v4: - Also remove overviews for newly added bpf_xdp_adjust_tail() and bpf_skb_get_xfrm_state(). - Remove vague statement about what helpers are restricted to GPL programs in "LICENSE" section for man page footer. - Replace license boilerplate with SPDX tag for Python script. v3: - Change license for man page. - Remove "for safety reasons" from man page header text. - Change "packets metadata" to "packets" in man page header text. - Move and fix comment on helpers introducing no overhead. - Remove "NOTES" section from man page footer. - Add "LICENSE" section to man page footer. - Edit description of file include/uapi/linux/bpf.h in man page footer. Signed-off-by: -
Daniel Borkmann authored
William Tu says: ==================== The patch series provide end-to-end eBPF tunnel testsute. A common topology is created below for all types of tunnels: Topology: --------- root namespace | at_ns0 namespace | ----------- | ----------- | tnl dev | | | tnl dev | (overlay network) ----------- | ----------- metadata-mode | native-mode with bpf | | ---------- | ---------- | veth1 | --------- | veth0 | (underlay network) ---------- peer ---------- Device Configuration -------------------- Root namespace with metadata-mode tunnel + BPF Device names and addresses: veth1 IP: 172.16.1.200, IPv6: 00::22 (underlay) tunnel dev <type>11, ex: gre11, IPv4: 10.1.1.200 (overlay) Namespace at_ns0 with native tunnel Device names and addresses: veth0 IPv4: 172.16.1.100, IPv6: 00::11 (underlay) tunnel dev <type>00, ex: gre00, IPv4: 10.1.1.100 (overlay) End-to-end ping packet flow --------------------------- Most of the tests start by namespace creation, device configuration, then ping the underlay and overlay network. When doing 'ping 10.1.1.100' from root namespace, the following operations happen: 1) Route lookup shows 10.1.1.100/24 belongs to tnl dev, fwd to tnl dev. 2) Tnl device's egress BPF program is triggered and set the tunnel metadata, with remote_ip=172.16.1.200 and others. 3) Outer tunnel header is prepended and route the packet to veth1's egress 4) veth0's ingress queue receive the tunneled packet at namespace at_ns0 5) Tunnel protocol handler, ex: vxlan_rcv, decap the packet 6) Forward the packet to the overlay tnl dev Test Cases ----------------------------- Tunnel Type | BPF Programs ----------------------------- GRE: gre_set_tunnel, gre_get_tunnel IP6GRE: ip6gretap_set_tunnel, ip6gretap_get_tunnel ERSPAN: erspan_set_tunnel, erspan_get_tunnel IP6ERSPAN: ip4ip6erspan_set_tunnel, ip4ip6erspan_get_tunnel VXLAN: vxlan_set_tunnel, vxlan_get_tunnel IP6VXLAN: ip6vxlan_set_tunnel, ip6vxlan_get_tunnel GENEVE: geneve_set_tunnel, geneve_get_tunnel IP6GENEVE: ip6geneve_set_tunnel, ip6geneve_get_tunnel IPIP: ipip_set_tunnel, ipip_get_tunnel IP6IP: ipip6_set_tunnel, ipip6_get_tunnel, ip6ip6_set_tunnel, ip6ip6_get_tunnel XFRM: xfrm_get_state ==================== Signed-off-by: -
William Tu authored
Move the testsuite to selftests/bpf/{test_tunnel_kern.c, test_tunnel.sh} Signed-off-by:William Tu <u9012063@gmail.com> Signed-off-by:
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William Tu authored
The patch migrates the original tests at samples/bpf/tcbpf2_kern.c and samples/bpf/test_tunnel_bpf.sh to selftests. There are a couple changes from the original: 1) add ipv6 vxlan, ipv6 geneve, ipv6 ipip tests 2) simplify the original ipip tests (remove iperf tests) 3) improve documentation 4) use bpf_ntoh* and bpf_hton* api In summary, 'test_tunnel_kern.o' contains the following bpf program: GRE: gre_set_tunnel, gre_get_tunnel IP6GRE: ip6gretap_set_tunnel, ip6gretap_get_tunnel ERSPAN: erspan_set_tunnel, erspan_get_tunnel IP6ERSPAN: ip4ip6erspan_set_tunnel, ip4ip6erspan_get_tunnel VXLAN: vxlan_set_tunnel, vxlan_get_tunnel IP6VXLAN: ip6vxlan_set_tunnel, ip6vxlan_get_tunnel GENEVE: geneve_set_tunnel, geneve_get_tunnel IP6GENEVE: ip6geneve_set_tunnel, ip6geneve_get_tunnel IPIP: ipip_set_tunnel, ipip_get_tunnel IP6IP: ipip6_set_tunnel, ipip6_get_tunnel, ip6ip6_set_tunnel, ip6ip6_get_tunnel XFRM: xfrm_get_state Signed-off-by: -
Nikita V. Shirokov authored
When bpf_adjust_tail was introduced for generic xdp, it changed skb's tail pointer, so it was pointing to the new "end of the packet". However skb's len field wasn't properly modified, so on the wire ethernet frame had original (or even bigger, if adjust_head was used) size. This diff is fixing this. Fixes: 198d83bb (" bpf: make generic xdp compatible w/ bpf_xdp_adjust_tail") Signed-off-by:
Nikita V. Shirokov <tehnerd@tehnerd.com> Signed-off-by:
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Jiri Olsa authored
Display the license "gpl" string in bpftool prog command, like: # bpftool prog list 5: tracepoint name func tag 57cd311f2e27366b gpl loaded_at Apr 26/09:37 uid 0 xlated 16B not jited memlock 4096B # bpftool --json --pretty prog show [{ "id": 5, "type": "tracepoint", "name": "func", "tag": "57cd311f2e27366b", "gpl_compatible": true, "loaded_at": "Apr 26/09:37", "uid": 0, "bytes_xlated": 16, "jited": false, "bytes_memlock": 4096 } ] Signed-off-by:Jiri Olsa <jolsa@kernel.org> Signed-off-by:
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Jiri Olsa authored
Syncing the bpf.h uapi header with tools. Signed-off-by:
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Jiri Olsa authored
Adding gpl_compatible flag to struct bpf_prog_info so it can be dumped via bpf_prog_get_info_by_fd and displayed via bpftool progs dump. Alexei noticed 4-byte hole in struct bpf_prog_info, so we put the u32 flags field in there, and we can keep adding bit fields in there without breaking user space. Signed-off-by:
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David S. Miller authored
Willem de Bruijn says: ==================== udp gso Segmentation offload reduces cycles/byte for large packets by amortizing the cost of protocol stack traversal. This patchset implements GSO for UDP. A process can concatenate and submit multiple datagrams to the same destination in one send call by setting socket option SOL_UDP/UDP_SEGMENT with the segment size, or passing an analogous cmsg at send time. The stack will send the entire large (up to network layer max size) datagram through the protocol layer. At the GSO layer, it is broken up in individual segments. All receive the same network layer header and UDP src and dst port. All but the last segment have the same UDP header, but the last may differ in length and checksum. Initial results show a significant reduction in UDP cycles/byte. See the main patch for more details and benchmark results. udp 876 MB/s 14873 msg/s 624666 calls/s 11,205,777,429 cycles udp gso 2139 MB/s 36282 msg/s 36282 calls/s 11,204,374,561 cycles The patch set is broken down as follows: - patch 1 is a prerequisite: code rearrangement, noop otherwise - patch 2 implements the gso logic - patch 3 adds protocol stack support for UDP_SEGMENT - patch 4,5,7 are refinements - patch 6 adds the cmsg interface - patch 8..11 are tests This idea was presented previously at netconf 2017-2 http://vger.kernel.org/netconf2017_files/rx_hardening_and_udp_gso.pdf Changes v1 -> v2 - Convert __udp_gso_segment to modify headers after skb_segment - Split main patch into two, one for gso logic, one for UDP_SEGMENT Changes RFC -> v1 - MSG_MORE: fixed, by allowing checksum offload with corking if gso - SKB_GSO_UDP_L4: made independent from SKB_GSO_UDP and removed skb_is_ufo() wrapper - NETIF_F_GSO_UDP_L4: add to netdev_features_string and to netdev-features.txt add BUILD_BUG_ON to match SKB_GSO_UDP_L4 value - UDP_MAX_SEGMENTS: introduce limit on number of segments per gso skb to avoid extreme cases like IP_MAX_MTU/IPV4_MIN_MTU - CHECKSUM_PARTIAL: test against missing feature after ndo_features_check if not supported return error, analogous to udp_send_check - MSG_ZEROCOPY: removed, deferred for now ==================== Signed-off-by:
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