Commit | Line | Data |
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3cd046f1 | 1 | #!/usr/bin/env python3 |
56a092c8 QM |
2 | # SPDX-License-Identifier: GPL-2.0-only |
3 | # | |
748c7c82 | 4 | # Copyright (C) 2018-2019 Netronome Systems, Inc. |
923a932c | 5 | # Copyright (C) 2021 Isovalent, Inc. |
56a092c8 QM |
6 | |
7 | # In case user attempts to run with Python 2. | |
8 | from __future__ import print_function | |
9 | ||
10 | import argparse | |
11 | import re | |
12 | import sys, os | |
fd0a38f9 QM |
13 | import subprocess |
14 | ||
56a092c8 QM |
15 | |
16 | class NoHelperFound(BaseException): | |
17 | pass | |
18 | ||
a67882a2 JS |
19 | class NoSyscallCommandFound(BaseException): |
20 | pass | |
21 | ||
56a092c8 QM |
22 | class ParsingError(BaseException): |
23 | def __init__(self, line='<line not provided>', reader=None): | |
24 | if reader: | |
25 | BaseException.__init__(self, | |
26 | 'Error at file offset %d, parsing line: %s' % | |
27 | (reader.tell(), line)) | |
28 | else: | |
29 | BaseException.__init__(self, 'Error parsing line: %s' % line) | |
30 | ||
a67882a2 JS |
31 | |
32 | class APIElement(object): | |
56a092c8 | 33 | """ |
a67882a2 JS |
34 | An object representing the description of an aspect of the eBPF API. |
35 | @proto: prototype of the API symbol | |
36 | @desc: textual description of the symbol | |
37 | @ret: (optional) description of any associated return value | |
56a092c8 QM |
38 | """ |
39 | def __init__(self, proto='', desc='', ret=''): | |
40 | self.proto = proto | |
41 | self.desc = desc | |
42 | self.ret = ret | |
43 | ||
a67882a2 JS |
44 | |
45 | class Helper(APIElement): | |
46 | """ | |
47 | An object representing the description of an eBPF helper function. | |
48 | @proto: function prototype of the helper function | |
49 | @desc: textual description of the helper function | |
50 | @ret: description of the return value of the helper function | |
51 | """ | |
56a092c8 QM |
52 | def proto_break_down(self): |
53 | """ | |
54 | Break down helper function protocol into smaller chunks: return type, | |
55 | name, distincts arguments. | |
56 | """ | |
748c7c82 | 57 | arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$') |
56a092c8 | 58 | res = {} |
6f96674d | 59 | proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') |
56a092c8 QM |
60 | |
61 | capture = proto_re.match(self.proto) | |
62 | res['ret_type'] = capture.group(1) | |
63 | res['ret_star'] = capture.group(2) | |
64 | res['name'] = capture.group(3) | |
65 | res['args'] = [] | |
66 | ||
67 | args = capture.group(4).split(', ') | |
68 | for a in args: | |
69 | capture = arg_re.match(a) | |
70 | res['args'].append({ | |
71 | 'type' : capture.group(1), | |
748c7c82 QM |
72 | 'star' : capture.group(5), |
73 | 'name' : capture.group(6) | |
56a092c8 QM |
74 | }) |
75 | ||
76 | return res | |
77 | ||
a67882a2 | 78 | |
56a092c8 QM |
79 | class HeaderParser(object): |
80 | """ | |
81 | An object used to parse a file in order to extract the documentation of a | |
82 | list of eBPF helper functions. All the helpers that can be retrieved are | |
83 | stored as Helper object, in the self.helpers() array. | |
84 | @filename: name of file to parse, usually include/uapi/linux/bpf.h in the | |
85 | kernel tree | |
86 | """ | |
87 | def __init__(self, filename): | |
88 | self.reader = open(filename, 'r') | |
89 | self.line = '' | |
90 | self.helpers = [] | |
a67882a2 | 91 | self.commands = [] |
71a3cdf8 UA |
92 | self.desc_unique_helpers = set() |
93 | self.define_unique_helpers = [] | |
0ba3929e UA |
94 | self.desc_syscalls = [] |
95 | self.enum_syscalls = [] | |
a67882a2 JS |
96 | |
97 | def parse_element(self): | |
98 | proto = self.parse_symbol() | |
f1f3f67f UA |
99 | desc = self.parse_desc(proto) |
100 | ret = self.parse_ret(proto) | |
a67882a2 | 101 | return APIElement(proto=proto, desc=desc, ret=ret) |
56a092c8 QM |
102 | |
103 | def parse_helper(self): | |
104 | proto = self.parse_proto() | |
f1f3f67f UA |
105 | desc = self.parse_desc(proto) |
106 | ret = self.parse_ret(proto) | |
56a092c8 QM |
107 | return Helper(proto=proto, desc=desc, ret=ret) |
108 | ||
a67882a2 | 109 | def parse_symbol(self): |
0ba3929e | 110 | p = re.compile(' \* ?(BPF\w+)$') |
a67882a2 JS |
111 | capture = p.match(self.line) |
112 | if not capture: | |
113 | raise NoSyscallCommandFound | |
114 | end_re = re.compile(' \* ?NOTES$') | |
115 | end = end_re.match(self.line) | |
116 | if end: | |
117 | raise NoSyscallCommandFound | |
118 | self.line = self.reader.readline() | |
119 | return capture.group(1) | |
120 | ||
56a092c8 QM |
121 | def parse_proto(self): |
122 | # Argument can be of shape: | |
123 | # - "void" | |
124 | # - "type name" | |
125 | # - "type *name" | |
126 | # - Same as above, with "const" and/or "struct" in front of type | |
127 | # - "..." (undefined number of arguments, for bpf_trace_printk()) | |
128 | # There is at least one term ("void"), and at most five arguments. | |
6f96674d | 129 | p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') |
56a092c8 QM |
130 | capture = p.match(self.line) |
131 | if not capture: | |
132 | raise NoHelperFound | |
133 | self.line = self.reader.readline() | |
134 | return capture.group(1) | |
135 | ||
f1f3f67f | 136 | def parse_desc(self, proto): |
eeacb716 | 137 | p = re.compile(' \* ?(?:\t| {5,8})Description$') |
56a092c8 QM |
138 | capture = p.match(self.line) |
139 | if not capture: | |
f1f3f67f | 140 | raise Exception("No description section found for " + proto) |
56a092c8 QM |
141 | # Description can be several lines, some of them possibly empty, and it |
142 | # stops when another subsection title is met. | |
143 | desc = '' | |
f1f3f67f | 144 | desc_present = False |
56a092c8 QM |
145 | while True: |
146 | self.line = self.reader.readline() | |
147 | if self.line == ' *\n': | |
148 | desc += '\n' | |
149 | else: | |
eeacb716 | 150 | p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') |
56a092c8 QM |
151 | capture = p.match(self.line) |
152 | if capture: | |
f1f3f67f | 153 | desc_present = True |
56a092c8 QM |
154 | desc += capture.group(1) + '\n' |
155 | else: | |
156 | break | |
f1f3f67f UA |
157 | |
158 | if not desc_present: | |
159 | raise Exception("No description found for " + proto) | |
56a092c8 QM |
160 | return desc |
161 | ||
f1f3f67f | 162 | def parse_ret(self, proto): |
eeacb716 | 163 | p = re.compile(' \* ?(?:\t| {5,8})Return$') |
56a092c8 QM |
164 | capture = p.match(self.line) |
165 | if not capture: | |
f1f3f67f | 166 | raise Exception("No return section found for " + proto) |
56a092c8 QM |
167 | # Return value description can be several lines, some of them possibly |
168 | # empty, and it stops when another subsection title is met. | |
169 | ret = '' | |
f1f3f67f | 170 | ret_present = False |
56a092c8 QM |
171 | while True: |
172 | self.line = self.reader.readline() | |
173 | if self.line == ' *\n': | |
174 | ret += '\n' | |
175 | else: | |
eeacb716 | 176 | p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') |
56a092c8 QM |
177 | capture = p.match(self.line) |
178 | if capture: | |
f1f3f67f | 179 | ret_present = True |
56a092c8 QM |
180 | ret += capture.group(1) + '\n' |
181 | else: | |
182 | break | |
f1f3f67f UA |
183 | |
184 | if not ret_present: | |
185 | raise Exception("No return found for " + proto) | |
56a092c8 QM |
186 | return ret |
187 | ||
0ba3929e | 188 | def seek_to(self, target, help_message, discard_lines = 1): |
a67882a2 JS |
189 | self.reader.seek(0) |
190 | offset = self.reader.read().find(target) | |
56a092c8 | 191 | if offset == -1: |
a67882a2 | 192 | raise Exception(help_message) |
56a092c8 QM |
193 | self.reader.seek(offset) |
194 | self.reader.readline() | |
0ba3929e UA |
195 | for _ in range(discard_lines): |
196 | self.reader.readline() | |
56a092c8 QM |
197 | self.line = self.reader.readline() |
198 | ||
0ba3929e | 199 | def parse_desc_syscall(self): |
a67882a2 JS |
200 | self.seek_to('* DOC: eBPF Syscall Commands', |
201 | 'Could not find start of eBPF syscall descriptions list') | |
202 | while True: | |
203 | try: | |
204 | command = self.parse_element() | |
205 | self.commands.append(command) | |
0ba3929e UA |
206 | self.desc_syscalls.append(command.proto) |
207 | ||
a67882a2 JS |
208 | except NoSyscallCommandFound: |
209 | break | |
210 | ||
0ba3929e UA |
211 | def parse_enum_syscall(self): |
212 | self.seek_to('enum bpf_cmd {', | |
213 | 'Could not find start of bpf_cmd enum', 0) | |
214 | # Searches for either one or more BPF\w+ enums | |
215 | bpf_p = re.compile('\s*(BPF\w+)+') | |
216 | # Searches for an enum entry assigned to another entry, | |
217 | # for e.g. BPF_PROG_RUN = BPF_PROG_TEST_RUN, which is | |
218 | # not documented hence should be skipped in check to | |
219 | # determine if the right number of syscalls are documented | |
220 | assign_p = re.compile('\s*(BPF\w+)\s*=\s*(BPF\w+)') | |
221 | bpf_cmd_str = '' | |
222 | while True: | |
223 | capture = assign_p.match(self.line) | |
224 | if capture: | |
225 | # Skip line if an enum entry is assigned to another entry | |
226 | self.line = self.reader.readline() | |
227 | continue | |
228 | capture = bpf_p.match(self.line) | |
229 | if capture: | |
230 | bpf_cmd_str += self.line | |
231 | else: | |
232 | break | |
233 | self.line = self.reader.readline() | |
234 | # Find the number of occurences of BPF\w+ | |
235 | self.enum_syscalls = re.findall('(BPF\w+)+', bpf_cmd_str) | |
236 | ||
71a3cdf8 | 237 | def parse_desc_helpers(self): |
a67882a2 JS |
238 | self.seek_to('* Start of BPF helper function descriptions:', |
239 | 'Could not find start of eBPF helper descriptions list') | |
56a092c8 QM |
240 | while True: |
241 | try: | |
242 | helper = self.parse_helper() | |
243 | self.helpers.append(helper) | |
71a3cdf8 UA |
244 | proto = helper.proto_break_down() |
245 | self.desc_unique_helpers.add(proto['name']) | |
56a092c8 QM |
246 | except NoHelperFound: |
247 | break | |
248 | ||
71a3cdf8 UA |
249 | def parse_define_helpers(self): |
250 | # Parse the number of FN(...) in #define __BPF_FUNC_MAPPER to compare | |
251 | # later with the number of unique function names present in description. | |
252 | # Note: seek_to(..) discards the first line below the target search text, | |
253 | # resulting in FN(unspec) being skipped and not added to self.define_unique_helpers. | |
254 | self.seek_to('#define __BPF_FUNC_MAPPER(FN)', | |
255 | 'Could not find start of eBPF helper definition list') | |
256 | # Searches for either one or more FN(\w+) defines or a backslash for newline | |
257 | p = re.compile('\s*(FN\(\w+\))+|\\\\') | |
258 | fn_defines_str = '' | |
259 | while True: | |
260 | capture = p.match(self.line) | |
261 | if capture: | |
262 | fn_defines_str += self.line | |
263 | else: | |
264 | break | |
265 | self.line = self.reader.readline() | |
266 | # Find the number of occurences of FN(\w+) | |
267 | self.define_unique_helpers = re.findall('FN\(\w+\)', fn_defines_str) | |
268 | ||
a67882a2 | 269 | def run(self): |
0ba3929e UA |
270 | self.parse_desc_syscall() |
271 | self.parse_enum_syscall() | |
71a3cdf8 UA |
272 | self.parse_desc_helpers() |
273 | self.parse_define_helpers() | |
56a092c8 | 274 | self.reader.close() |
56a092c8 QM |
275 | |
276 | ############################################################################### | |
277 | ||
278 | class Printer(object): | |
279 | """ | |
280 | A generic class for printers. Printers should be created with an array of | |
281 | Helper objects, and implement a way to print them in the desired fashion. | |
923a932c | 282 | @parser: A HeaderParser with objects to print to standard output |
56a092c8 | 283 | """ |
923a932c JS |
284 | def __init__(self, parser): |
285 | self.parser = parser | |
286 | self.elements = [] | |
56a092c8 QM |
287 | |
288 | def print_header(self): | |
289 | pass | |
290 | ||
291 | def print_footer(self): | |
292 | pass | |
293 | ||
294 | def print_one(self, helper): | |
295 | pass | |
296 | ||
297 | def print_all(self): | |
298 | self.print_header() | |
923a932c JS |
299 | for elem in self.elements: |
300 | self.print_one(elem) | |
56a092c8 QM |
301 | self.print_footer() |
302 | ||
0ba3929e UA |
303 | def elem_number_check(self, desc_unique_elem, define_unique_elem, type, instance): |
304 | """ | |
305 | Checks the number of helpers/syscalls documented within the header file | |
306 | description with those defined as part of enum/macro and raise an | |
307 | Exception if they don't match. | |
308 | """ | |
309 | nr_desc_unique_elem = len(desc_unique_elem) | |
310 | nr_define_unique_elem = len(define_unique_elem) | |
311 | if nr_desc_unique_elem != nr_define_unique_elem: | |
312 | exception_msg = ''' | |
313 | The number of unique %s in description (%d) doesn\'t match the number of unique %s defined in %s (%d) | |
314 | ''' % (type, nr_desc_unique_elem, type, instance, nr_define_unique_elem) | |
315 | if nr_desc_unique_elem < nr_define_unique_elem: | |
316 | # Function description is parsed until no helper is found (which can be due to | |
317 | # misformatting). Hence, only print the first missing/misformatted helper/enum. | |
318 | exception_msg += ''' | |
319 | The description for %s is not present or formatted correctly. | |
320 | ''' % (define_unique_elem[nr_desc_unique_elem]) | |
321 | raise Exception(exception_msg) | |
923a932c | 322 | |
56a092c8 QM |
323 | class PrinterRST(Printer): |
324 | """ | |
923a932c JS |
325 | A generic class for printers that print ReStructured Text. Printers should |
326 | be created with a HeaderParser object, and implement a way to print API | |
327 | elements in the desired fashion. | |
328 | @parser: A HeaderParser with objects to print to standard output | |
56a092c8 | 329 | """ |
923a932c JS |
330 | def __init__(self, parser): |
331 | self.parser = parser | |
332 | ||
333 | def print_license(self): | |
334 | license = '''\ | |
56a092c8 QM |
335 | .. Copyright (C) All BPF authors and contributors from 2014 to present. |
336 | .. See git log include/uapi/linux/bpf.h in kernel tree for details. | |
337 | .. | |
5cb62b75 | 338 | .. SPDX-License-Identifier: Linux-man-pages-copyleft |
56a092c8 QM |
339 | .. |
340 | .. Please do not edit this file. It was generated from the documentation | |
341 | .. located in file include/uapi/linux/bpf.h of the Linux kernel sources | |
923a932c | 342 | .. (helpers description), and from scripts/bpf_doc.py in the same |
56a092c8 | 343 | .. repository (header and footer). |
923a932c JS |
344 | ''' |
345 | print(license) | |
346 | ||
347 | def print_elem(self, elem): | |
348 | if (elem.desc): | |
349 | print('\tDescription') | |
350 | # Do not strip all newline characters: formatted code at the end of | |
351 | # a section must be followed by a blank line. | |
352 | for line in re.sub('\n$', '', elem.desc, count=1).split('\n'): | |
353 | print('{}{}'.format('\t\t' if line else '', line)) | |
354 | ||
355 | if (elem.ret): | |
356 | print('\tReturn') | |
357 | for line in elem.ret.rstrip().split('\n'): | |
358 | print('{}{}'.format('\t\t' if line else '', line)) | |
359 | ||
360 | print('') | |
56a092c8 | 361 | |
fd0a38f9 QM |
362 | def get_kernel_version(self): |
363 | try: | |
364 | version = subprocess.run(['git', 'describe'], cwd=linuxRoot, | |
365 | capture_output=True, check=True) | |
366 | version = version.stdout.decode().rstrip() | |
367 | except: | |
368 | try: | |
369 | version = subprocess.run(['make', 'kernelversion'], cwd=linuxRoot, | |
370 | capture_output=True, check=True) | |
371 | version = version.stdout.decode().rstrip() | |
372 | except: | |
373 | return 'Linux' | |
374 | return 'Linux {version}'.format(version=version) | |
375 | ||
923a932c JS |
376 | class PrinterHelpersRST(PrinterRST): |
377 | """ | |
378 | A printer for dumping collected information about helpers as a ReStructured | |
379 | Text page compatible with the rst2man program, which can be used to | |
380 | generate a manual page for the helpers. | |
381 | @parser: A HeaderParser with Helper objects to print to standard output | |
382 | """ | |
383 | def __init__(self, parser): | |
384 | self.elements = parser.helpers | |
0ba3929e | 385 | self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER') |
923a932c JS |
386 | |
387 | def print_header(self): | |
388 | header = '''\ | |
56a092c8 QM |
389 | =========== |
390 | BPF-HELPERS | |
391 | =========== | |
392 | ------------------------------------------------------------------------------- | |
393 | list of eBPF helper functions | |
394 | ------------------------------------------------------------------------------- | |
395 | ||
396 | :Manual section: 7 | |
fd0a38f9 | 397 | :Version: {version} |
56a092c8 QM |
398 | |
399 | DESCRIPTION | |
400 | =========== | |
401 | ||
402 | The extended Berkeley Packet Filter (eBPF) subsystem consists in programs | |
403 | written in a pseudo-assembly language, then attached to one of the several | |
404 | kernel hooks and run in reaction of specific events. This framework differs | |
405 | from the older, "classic" BPF (or "cBPF") in several aspects, one of them being | |
406 | the ability to call special functions (or "helpers") from within a program. | |
407 | These functions are restricted to a white-list of helpers defined in the | |
408 | kernel. | |
409 | ||
410 | These helpers are used by eBPF programs to interact with the system, or with | |
411 | the context in which they work. For instance, they can be used to print | |
412 | debugging messages, to get the time since the system was booted, to interact | |
413 | with eBPF maps, or to manipulate network packets. Since there are several eBPF | |
414 | program types, and that they do not run in the same context, each program type | |
415 | can only call a subset of those helpers. | |
416 | ||
417 | Due to eBPF conventions, a helper can not have more than five arguments. | |
418 | ||
419 | Internally, eBPF programs call directly into the compiled helper functions | |
420 | without requiring any foreign-function interface. As a result, calling helpers | |
421 | introduces no overhead, thus offering excellent performance. | |
422 | ||
423 | This document is an attempt to list and document the helpers available to eBPF | |
424 | developers. They are sorted by chronological order (the oldest helpers in the | |
425 | kernel at the top). | |
426 | ||
427 | HELPERS | |
428 | ======= | |
429 | ''' | |
fd0a38f9 QM |
430 | kernelVersion = self.get_kernel_version() |
431 | ||
923a932c | 432 | PrinterRST.print_license(self) |
fd0a38f9 | 433 | print(header.format(version=kernelVersion)) |
56a092c8 QM |
434 | |
435 | def print_footer(self): | |
436 | footer = ''' | |
437 | EXAMPLES | |
438 | ======== | |
439 | ||
440 | Example usage for most of the eBPF helpers listed in this manual page are | |
441 | available within the Linux kernel sources, at the following locations: | |
442 | ||
443 | * *samples/bpf/* | |
444 | * *tools/testing/selftests/bpf/* | |
445 | ||
446 | LICENSE | |
447 | ======= | |
448 | ||
449 | eBPF programs can have an associated license, passed along with the bytecode | |
450 | instructions to the kernel when the programs are loaded. The format for that | |
451 | string is identical to the one in use for kernel modules (Dual licenses, such | |
452 | as "Dual BSD/GPL", may be used). Some helper functions are only accessible to | |
453 | programs that are compatible with the GNU Privacy License (GPL). | |
454 | ||
455 | In order to use such helpers, the eBPF program must be loaded with the correct | |
456 | license string passed (via **attr**) to the **bpf**\ () system call, and this | |
457 | generally translates into the C source code of the program containing a line | |
458 | similar to the following: | |
459 | ||
460 | :: | |
461 | ||
462 | char ____license[] __attribute__((section("license"), used)) = "GPL"; | |
463 | ||
464 | IMPLEMENTATION | |
465 | ============== | |
466 | ||
467 | This manual page is an effort to document the existing eBPF helper functions. | |
468 | But as of this writing, the BPF sub-system is under heavy development. New eBPF | |
469 | program or map types are added, along with new helper functions. Some helpers | |
470 | are occasionally made available for additional program types. So in spite of | |
471 | the efforts of the community, this page might not be up-to-date. If you want to | |
472 | check by yourself what helper functions exist in your kernel, or what types of | |
473 | programs they can support, here are some files among the kernel tree that you | |
474 | may be interested in: | |
475 | ||
476 | * *include/uapi/linux/bpf.h* is the main BPF header. It contains the full list | |
477 | of all helper functions, as well as many other BPF definitions including most | |
478 | of the flags, structs or constants used by the helpers. | |
479 | * *net/core/filter.c* contains the definition of most network-related helper | |
480 | functions, and the list of program types from which they can be used. | |
481 | * *kernel/trace/bpf_trace.c* is the equivalent for most tracing program-related | |
482 | helpers. | |
483 | * *kernel/bpf/verifier.c* contains the functions used to check that valid types | |
484 | of eBPF maps are used with a given helper function. | |
485 | * *kernel/bpf/* directory contains other files in which additional helpers are | |
486 | defined (for cgroups, sockmaps, etc.). | |
ab8d7809 QM |
487 | * The bpftool utility can be used to probe the availability of helper functions |
488 | on the system (as well as supported program and map types, and a number of | |
489 | other parameters). To do so, run **bpftool feature probe** (see | |
490 | **bpftool-feature**\ (8) for details). Add the **unprivileged** keyword to | |
491 | list features available to unprivileged users. | |
56a092c8 QM |
492 | |
493 | Compatibility between helper functions and program types can generally be found | |
494 | in the files where helper functions are defined. Look for the **struct | |
495 | bpf_func_proto** objects and for functions returning them: these functions | |
496 | contain a list of helpers that a given program type can call. Note that the | |
497 | **default:** label of the **switch ... case** used to filter helpers can call | |
498 | other functions, themselves allowing access to additional helpers. The | |
499 | requirement for GPL license is also in those **struct bpf_func_proto**. | |
500 | ||
501 | Compatibility between helper functions and map types can be found in the | |
502 | **check_map_func_compatibility**\ () function in file *kernel/bpf/verifier.c*. | |
503 | ||
504 | Helper functions that invalidate the checks on **data** and **data_end** | |
505 | pointers for network processing are listed in function | |
506 | **bpf_helper_changes_pkt_data**\ () in file *net/core/filter.c*. | |
507 | ||
508 | SEE ALSO | |
509 | ======== | |
510 | ||
511 | **bpf**\ (2), | |
ab8d7809 | 512 | **bpftool**\ (8), |
56a092c8 QM |
513 | **cgroups**\ (7), |
514 | **ip**\ (8), | |
515 | **perf_event_open**\ (2), | |
516 | **sendmsg**\ (2), | |
517 | **socket**\ (7), | |
518 | **tc-bpf**\ (8)''' | |
519 | print(footer) | |
520 | ||
521 | def print_proto(self, helper): | |
522 | """ | |
523 | Format function protocol with bold and italics markers. This makes RST | |
524 | file less readable, but gives nice results in the manual page. | |
525 | """ | |
526 | proto = helper.proto_break_down() | |
527 | ||
528 | print('**%s %s%s(' % (proto['ret_type'], | |
529 | proto['ret_star'].replace('*', '\\*'), | |
530 | proto['name']), | |
531 | end='') | |
532 | ||
533 | comma = '' | |
534 | for a in proto['args']: | |
535 | one_arg = '{}{}'.format(comma, a['type']) | |
536 | if a['name']: | |
537 | if a['star']: | |
538 | one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*')) | |
539 | else: | |
540 | one_arg += '** ' | |
541 | one_arg += '*{}*\\ **'.format(a['name']) | |
542 | comma = ', ' | |
543 | print(one_arg, end='') | |
544 | ||
545 | print(')**') | |
546 | ||
547 | def print_one(self, helper): | |
548 | self.print_proto(helper) | |
923a932c | 549 | self.print_elem(helper) |
56a092c8 | 550 | |
56a092c8 | 551 | |
a67882a2 JS |
552 | class PrinterSyscallRST(PrinterRST): |
553 | """ | |
554 | A printer for dumping collected information about the syscall API as a | |
555 | ReStructured Text page compatible with the rst2man program, which can be | |
556 | used to generate a manual page for the syscall. | |
557 | @parser: A HeaderParser with APIElement objects to print to standard | |
558 | output | |
559 | """ | |
560 | def __init__(self, parser): | |
561 | self.elements = parser.commands | |
0ba3929e | 562 | self.elem_number_check(parser.desc_syscalls, parser.enum_syscalls, 'syscall', 'bpf_cmd') |
a67882a2 JS |
563 | |
564 | def print_header(self): | |
565 | header = '''\ | |
566 | === | |
567 | bpf | |
568 | === | |
569 | ------------------------------------------------------------------------------- | |
570 | Perform a command on an extended BPF object | |
571 | ------------------------------------------------------------------------------- | |
572 | ||
573 | :Manual section: 2 | |
574 | ||
575 | COMMANDS | |
576 | ======== | |
577 | ''' | |
578 | PrinterRST.print_license(self) | |
579 | print(header) | |
580 | ||
581 | def print_one(self, command): | |
582 | print('**%s**' % (command.proto)) | |
583 | self.print_elem(command) | |
56a092c8 | 584 | |
56a092c8 | 585 | |
7a387bed AN |
586 | class PrinterHelpers(Printer): |
587 | """ | |
588 | A printer for dumping collected information about helpers as C header to | |
589 | be included from BPF program. | |
923a932c | 590 | @parser: A HeaderParser with Helper objects to print to standard output |
7a387bed | 591 | """ |
923a932c JS |
592 | def __init__(self, parser): |
593 | self.elements = parser.helpers | |
0ba3929e | 594 | self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER') |
7a387bed AN |
595 | |
596 | type_fwds = [ | |
597 | 'struct bpf_fib_lookup', | |
e9ddbb77 | 598 | 'struct bpf_sk_lookup', |
7a387bed AN |
599 | 'struct bpf_perf_event_data', |
600 | 'struct bpf_perf_event_value', | |
5996a587 | 601 | 'struct bpf_pidns_info', |
821f5c90 | 602 | 'struct bpf_redir_neigh', |
7a387bed AN |
603 | 'struct bpf_sock', |
604 | 'struct bpf_sock_addr', | |
605 | 'struct bpf_sock_ops', | |
606 | 'struct bpf_sock_tuple', | |
607 | 'struct bpf_spin_lock', | |
608 | 'struct bpf_sysctl', | |
609 | 'struct bpf_tcp_sock', | |
610 | 'struct bpf_tunnel_key', | |
611 | 'struct bpf_xfrm_state', | |
3f6719c7 | 612 | 'struct linux_binprm', |
7a387bed AN |
613 | 'struct pt_regs', |
614 | 'struct sk_reuseport_md', | |
615 | 'struct sockaddr', | |
616 | 'struct tcphdr', | |
492e639f | 617 | 'struct seq_file', |
af7ec138 | 618 | 'struct tcp6_sock', |
478cfbdf YS |
619 | 'struct tcp_sock', |
620 | 'struct tcp_timewait_sock', | |
621 | 'struct tcp_request_sock', | |
0d4fad3e | 622 | 'struct udp6_sock', |
9eeb3aa3 | 623 | 'struct unix_sock', |
fa28dcb8 | 624 | 'struct task_struct', |
7a387bed AN |
625 | |
626 | 'struct __sk_buff', | |
627 | 'struct sk_msg_md', | |
e0b68fb1 | 628 | 'struct xdp_md', |
6e22ab9d | 629 | 'struct path', |
c4d0bfb4 | 630 | 'struct btf_ptr', |
27672f0d | 631 | 'struct inode', |
4f19cab7 FR |
632 | 'struct socket', |
633 | 'struct file', | |
b00628b1 | 634 | 'struct bpf_timer', |
3bc253c2 | 635 | 'struct mptcp_sock', |
97e03f52 | 636 | 'struct bpf_dynptr', |
33bf9885 MM |
637 | 'struct iphdr', |
638 | 'struct ipv6hdr', | |
7a387bed AN |
639 | ] |
640 | known_types = { | |
641 | '...', | |
642 | 'void', | |
643 | 'const void', | |
644 | 'char', | |
645 | 'const char', | |
646 | 'int', | |
647 | 'long', | |
648 | 'unsigned long', | |
649 | ||
650 | '__be16', | |
651 | '__be32', | |
652 | '__wsum', | |
653 | ||
654 | 'struct bpf_fib_lookup', | |
655 | 'struct bpf_perf_event_data', | |
656 | 'struct bpf_perf_event_value', | |
b4490c5c | 657 | 'struct bpf_pidns_info', |
ba452c9e | 658 | 'struct bpf_redir_neigh', |
e9ddbb77 | 659 | 'struct bpf_sk_lookup', |
7a387bed AN |
660 | 'struct bpf_sock', |
661 | 'struct bpf_sock_addr', | |
662 | 'struct bpf_sock_ops', | |
663 | 'struct bpf_sock_tuple', | |
664 | 'struct bpf_spin_lock', | |
665 | 'struct bpf_sysctl', | |
666 | 'struct bpf_tcp_sock', | |
667 | 'struct bpf_tunnel_key', | |
668 | 'struct bpf_xfrm_state', | |
3f6719c7 | 669 | 'struct linux_binprm', |
7a387bed AN |
670 | 'struct pt_regs', |
671 | 'struct sk_reuseport_md', | |
672 | 'struct sockaddr', | |
673 | 'struct tcphdr', | |
492e639f | 674 | 'struct seq_file', |
af7ec138 | 675 | 'struct tcp6_sock', |
478cfbdf YS |
676 | 'struct tcp_sock', |
677 | 'struct tcp_timewait_sock', | |
678 | 'struct tcp_request_sock', | |
0d4fad3e | 679 | 'struct udp6_sock', |
9eeb3aa3 | 680 | 'struct unix_sock', |
fa28dcb8 | 681 | 'struct task_struct', |
6e22ab9d | 682 | 'struct path', |
c4d0bfb4 | 683 | 'struct btf_ptr', |
27672f0d | 684 | 'struct inode', |
4f19cab7 FR |
685 | 'struct socket', |
686 | 'struct file', | |
b00628b1 | 687 | 'struct bpf_timer', |
3bc253c2 | 688 | 'struct mptcp_sock', |
97e03f52 | 689 | 'struct bpf_dynptr', |
33bf9885 MM |
690 | 'struct iphdr', |
691 | 'struct ipv6hdr', | |
7a387bed AN |
692 | } |
693 | mapped_types = { | |
694 | 'u8': '__u8', | |
695 | 'u16': '__u16', | |
696 | 'u32': '__u32', | |
697 | 'u64': '__u64', | |
698 | 's8': '__s8', | |
699 | 's16': '__s16', | |
700 | 's32': '__s32', | |
701 | 's64': '__s64', | |
702 | 'size_t': 'unsigned long', | |
703 | 'struct bpf_map': 'void', | |
704 | 'struct sk_buff': 'struct __sk_buff', | |
705 | 'const struct sk_buff': 'const struct __sk_buff', | |
706 | 'struct sk_msg_buff': 'struct sk_msg_md', | |
707 | 'struct xdp_buff': 'struct xdp_md', | |
708 | } | |
e9ddbb77 JS |
709 | # Helpers overloaded for different context types. |
710 | overloaded_helpers = [ | |
711 | 'bpf_get_socket_cookie', | |
712 | 'bpf_sk_assign', | |
713 | ] | |
7a387bed AN |
714 | |
715 | def print_header(self): | |
716 | header = '''\ | |
923a932c | 717 | /* This is auto-generated file. See bpf_doc.py for details. */ |
7a387bed AN |
718 | |
719 | /* Forward declarations of BPF structs */''' | |
720 | ||
721 | print(header) | |
722 | for fwd in self.type_fwds: | |
723 | print('%s;' % fwd) | |
724 | print('') | |
725 | ||
726 | def print_footer(self): | |
727 | footer = '' | |
728 | print(footer) | |
729 | ||
730 | def map_type(self, t): | |
731 | if t in self.known_types: | |
732 | return t | |
733 | if t in self.mapped_types: | |
734 | return self.mapped_types[t] | |
ab81e203 JS |
735 | print("Unrecognized type '%s', please add it to known types!" % t, |
736 | file=sys.stderr) | |
7a387bed AN |
737 | sys.exit(1) |
738 | ||
739 | seen_helpers = set() | |
740 | ||
741 | def print_one(self, helper): | |
742 | proto = helper.proto_break_down() | |
743 | ||
744 | if proto['name'] in self.seen_helpers: | |
745 | return | |
746 | self.seen_helpers.add(proto['name']) | |
747 | ||
748 | print('/*') | |
749 | print(" * %s" % proto['name']) | |
750 | print(" *") | |
751 | if (helper.desc): | |
752 | # Do not strip all newline characters: formatted code at the end of | |
753 | # a section must be followed by a blank line. | |
754 | for line in re.sub('\n$', '', helper.desc, count=1).split('\n'): | |
755 | print(' *{}{}'.format(' \t' if line else '', line)) | |
756 | ||
757 | if (helper.ret): | |
758 | print(' *') | |
759 | print(' * Returns') | |
760 | for line in helper.ret.rstrip().split('\n'): | |
761 | print(' *{}{}'.format(' \t' if line else '', line)) | |
762 | ||
763 | print(' */') | |
764 | print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']), | |
765 | proto['ret_star'], proto['name']), end='') | |
766 | comma = '' | |
767 | for i, a in enumerate(proto['args']): | |
768 | t = a['type'] | |
769 | n = a['name'] | |
e9ddbb77 | 770 | if proto['name'] in self.overloaded_helpers and i == 0: |
7a387bed AN |
771 | t = 'void' |
772 | n = 'ctx' | |
773 | one_arg = '{}{}'.format(comma, self.map_type(t)) | |
774 | if n: | |
775 | if a['star']: | |
776 | one_arg += ' {}'.format(a['star']) | |
777 | else: | |
778 | one_arg += ' ' | |
779 | one_arg += '{}'.format(n) | |
780 | comma = ', ' | |
781 | print(one_arg, end='') | |
782 | ||
783 | print(') = (void *) %d;' % len(self.seen_helpers)) | |
784 | print('') | |
785 | ||
56a092c8 QM |
786 | ############################################################################### |
787 | ||
788 | # If script is launched from scripts/ from kernel tree and can access | |
789 | # ../include/uapi/linux/bpf.h, use it as a default name for the file to parse, | |
790 | # otherwise the --filename argument will be required from the command line. | |
791 | script = os.path.abspath(sys.argv[0]) | |
792 | linuxRoot = os.path.dirname(os.path.dirname(script)) | |
793 | bpfh = os.path.join(linuxRoot, 'include/uapi/linux/bpf.h') | |
794 | ||
923a932c JS |
795 | printers = { |
796 | 'helpers': PrinterHelpersRST, | |
a67882a2 | 797 | 'syscall': PrinterSyscallRST, |
923a932c JS |
798 | } |
799 | ||
56a092c8 | 800 | argParser = argparse.ArgumentParser(description=""" |
923a932c | 801 | Parse eBPF header file and generate documentation for the eBPF API. |
56a092c8 QM |
802 | The RST-formatted output produced can be turned into a manual page with the |
803 | rst2man utility. | |
804 | """) | |
7a387bed AN |
805 | argParser.add_argument('--header', action='store_true', |
806 | help='generate C header file') | |
56a092c8 QM |
807 | if (os.path.isfile(bpfh)): |
808 | argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h', | |
809 | default=bpfh) | |
810 | else: | |
811 | argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h') | |
923a932c JS |
812 | argParser.add_argument('target', nargs='?', default='helpers', |
813 | choices=printers.keys(), help='eBPF API target') | |
56a092c8 QM |
814 | args = argParser.parse_args() |
815 | ||
816 | # Parse file. | |
817 | headerParser = HeaderParser(args.filename) | |
818 | headerParser.run() | |
819 | ||
820 | # Print formatted output to standard output. | |
7a387bed | 821 | if args.header: |
a67882a2 JS |
822 | if args.target != 'helpers': |
823 | raise NotImplementedError('Only helpers header generation is supported') | |
923a932c | 824 | printer = PrinterHelpers(headerParser) |
7a387bed | 825 | else: |
923a932c | 826 | printer = printers[args.target](headerParser) |
56a092c8 | 827 | printer.print_all() |