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