mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
97e03f5210
This patch adds the bulk of the verifier work for supporting dynamic pointers (dynptrs) in bpf. A bpf_dynptr is opaque to the bpf program. It is a 16-byte structure defined internally as: struct bpf_dynptr_kern { void *data; u32 size; u32 offset; } __aligned(8); The upper 8 bits of *size* is reserved (it contains extra metadata about read-only status and dynptr type). Consequently, a dynptr only supports memory less than 16 MB. There are different types of dynptrs (eg malloc, ringbuf, ...). In this patchset, the most basic one, dynptrs to a bpf program's local memory, is added. For now only local memory that is of reg type PTR_TO_MAP_VALUE is supported. In the verifier, dynptr state information will be tracked in stack slots. When the program passes in an uninitialized dynptr (ARG_PTR_TO_DYNPTR | MEM_UNINIT), the stack slots corresponding to the frame pointer where the dynptr resides at are marked STACK_DYNPTR. For helper functions that take in initialized dynptrs (eg bpf_dynptr_read + bpf_dynptr_write which are added later in this patchset), the verifier enforces that the dynptr has been initialized properly by checking that their corresponding stack slots have been marked as STACK_DYNPTR. The 6th patch in this patchset adds test cases that the verifier should successfully reject, such as for example attempting to use a dynptr after doing a direct write into it inside the bpf program. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20220523210712.3641569-2-joannelkoong@gmail.com
825 lines
29 KiB
Python
Executable File
825 lines
29 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
# SPDX-License-Identifier: GPL-2.0-only
|
|
#
|
|
# Copyright (C) 2018-2019 Netronome Systems, Inc.
|
|
# Copyright (C) 2021 Isovalent, Inc.
|
|
|
|
# In case user attempts to run with Python 2.
|
|
from __future__ import print_function
|
|
|
|
import argparse
|
|
import re
|
|
import sys, os
|
|
|
|
class NoHelperFound(BaseException):
|
|
pass
|
|
|
|
class NoSyscallCommandFound(BaseException):
|
|
pass
|
|
|
|
class ParsingError(BaseException):
|
|
def __init__(self, line='<line not provided>', reader=None):
|
|
if reader:
|
|
BaseException.__init__(self,
|
|
'Error at file offset %d, parsing line: %s' %
|
|
(reader.tell(), line))
|
|
else:
|
|
BaseException.__init__(self, 'Error parsing line: %s' % line)
|
|
|
|
|
|
class APIElement(object):
|
|
"""
|
|
An object representing the description of an aspect of the eBPF API.
|
|
@proto: prototype of the API symbol
|
|
@desc: textual description of the symbol
|
|
@ret: (optional) description of any associated return value
|
|
"""
|
|
def __init__(self, proto='', desc='', ret=''):
|
|
self.proto = proto
|
|
self.desc = desc
|
|
self.ret = ret
|
|
|
|
|
|
class Helper(APIElement):
|
|
"""
|
|
An object representing the description of an eBPF helper function.
|
|
@proto: function prototype of the helper function
|
|
@desc: textual description of the helper function
|
|
@ret: description of the return value of the helper function
|
|
"""
|
|
def proto_break_down(self):
|
|
"""
|
|
Break down helper function protocol into smaller chunks: return type,
|
|
name, distincts arguments.
|
|
"""
|
|
arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$')
|
|
res = {}
|
|
proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$')
|
|
|
|
capture = proto_re.match(self.proto)
|
|
res['ret_type'] = capture.group(1)
|
|
res['ret_star'] = capture.group(2)
|
|
res['name'] = capture.group(3)
|
|
res['args'] = []
|
|
|
|
args = capture.group(4).split(', ')
|
|
for a in args:
|
|
capture = arg_re.match(a)
|
|
res['args'].append({
|
|
'type' : capture.group(1),
|
|
'star' : capture.group(5),
|
|
'name' : capture.group(6)
|
|
})
|
|
|
|
return res
|
|
|
|
|
|
class HeaderParser(object):
|
|
"""
|
|
An object used to parse a file in order to extract the documentation of a
|
|
list of eBPF helper functions. All the helpers that can be retrieved are
|
|
stored as Helper object, in the self.helpers() array.
|
|
@filename: name of file to parse, usually include/uapi/linux/bpf.h in the
|
|
kernel tree
|
|
"""
|
|
def __init__(self, filename):
|
|
self.reader = open(filename, 'r')
|
|
self.line = ''
|
|
self.helpers = []
|
|
self.commands = []
|
|
self.desc_unique_helpers = set()
|
|
self.define_unique_helpers = []
|
|
self.desc_syscalls = []
|
|
self.enum_syscalls = []
|
|
|
|
def parse_element(self):
|
|
proto = self.parse_symbol()
|
|
desc = self.parse_desc(proto)
|
|
ret = self.parse_ret(proto)
|
|
return APIElement(proto=proto, desc=desc, ret=ret)
|
|
|
|
def parse_helper(self):
|
|
proto = self.parse_proto()
|
|
desc = self.parse_desc(proto)
|
|
ret = self.parse_ret(proto)
|
|
return Helper(proto=proto, desc=desc, ret=ret)
|
|
|
|
def parse_symbol(self):
|
|
p = re.compile(' \* ?(BPF\w+)$')
|
|
capture = p.match(self.line)
|
|
if not capture:
|
|
raise NoSyscallCommandFound
|
|
end_re = re.compile(' \* ?NOTES$')
|
|
end = end_re.match(self.line)
|
|
if end:
|
|
raise NoSyscallCommandFound
|
|
self.line = self.reader.readline()
|
|
return capture.group(1)
|
|
|
|
def parse_proto(self):
|
|
# Argument can be of shape:
|
|
# - "void"
|
|
# - "type name"
|
|
# - "type *name"
|
|
# - Same as above, with "const" and/or "struct" in front of type
|
|
# - "..." (undefined number of arguments, for bpf_trace_printk())
|
|
# There is at least one term ("void"), and at most five arguments.
|
|
p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$')
|
|
capture = p.match(self.line)
|
|
if not capture:
|
|
raise NoHelperFound
|
|
self.line = self.reader.readline()
|
|
return capture.group(1)
|
|
|
|
def parse_desc(self, proto):
|
|
p = re.compile(' \* ?(?:\t| {5,8})Description$')
|
|
capture = p.match(self.line)
|
|
if not capture:
|
|
raise Exception("No description section found for " + proto)
|
|
# Description can be several lines, some of them possibly empty, and it
|
|
# stops when another subsection title is met.
|
|
desc = ''
|
|
desc_present = False
|
|
while True:
|
|
self.line = self.reader.readline()
|
|
if self.line == ' *\n':
|
|
desc += '\n'
|
|
else:
|
|
p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
|
|
capture = p.match(self.line)
|
|
if capture:
|
|
desc_present = True
|
|
desc += capture.group(1) + '\n'
|
|
else:
|
|
break
|
|
|
|
if not desc_present:
|
|
raise Exception("No description found for " + proto)
|
|
return desc
|
|
|
|
def parse_ret(self, proto):
|
|
p = re.compile(' \* ?(?:\t| {5,8})Return$')
|
|
capture = p.match(self.line)
|
|
if not capture:
|
|
raise Exception("No return section found for " + proto)
|
|
# Return value description can be several lines, some of them possibly
|
|
# empty, and it stops when another subsection title is met.
|
|
ret = ''
|
|
ret_present = False
|
|
while True:
|
|
self.line = self.reader.readline()
|
|
if self.line == ' *\n':
|
|
ret += '\n'
|
|
else:
|
|
p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
|
|
capture = p.match(self.line)
|
|
if capture:
|
|
ret_present = True
|
|
ret += capture.group(1) + '\n'
|
|
else:
|
|
break
|
|
|
|
if not ret_present:
|
|
raise Exception("No return found for " + proto)
|
|
return ret
|
|
|
|
def seek_to(self, target, help_message, discard_lines = 1):
|
|
self.reader.seek(0)
|
|
offset = self.reader.read().find(target)
|
|
if offset == -1:
|
|
raise Exception(help_message)
|
|
self.reader.seek(offset)
|
|
self.reader.readline()
|
|
for _ in range(discard_lines):
|
|
self.reader.readline()
|
|
self.line = self.reader.readline()
|
|
|
|
def parse_desc_syscall(self):
|
|
self.seek_to('* DOC: eBPF Syscall Commands',
|
|
'Could not find start of eBPF syscall descriptions list')
|
|
while True:
|
|
try:
|
|
command = self.parse_element()
|
|
self.commands.append(command)
|
|
self.desc_syscalls.append(command.proto)
|
|
|
|
except NoSyscallCommandFound:
|
|
break
|
|
|
|
def parse_enum_syscall(self):
|
|
self.seek_to('enum bpf_cmd {',
|
|
'Could not find start of bpf_cmd enum', 0)
|
|
# Searches for either one or more BPF\w+ enums
|
|
bpf_p = re.compile('\s*(BPF\w+)+')
|
|
# Searches for an enum entry assigned to another entry,
|
|
# for e.g. BPF_PROG_RUN = BPF_PROG_TEST_RUN, which is
|
|
# not documented hence should be skipped in check to
|
|
# determine if the right number of syscalls are documented
|
|
assign_p = re.compile('\s*(BPF\w+)\s*=\s*(BPF\w+)')
|
|
bpf_cmd_str = ''
|
|
while True:
|
|
capture = assign_p.match(self.line)
|
|
if capture:
|
|
# Skip line if an enum entry is assigned to another entry
|
|
self.line = self.reader.readline()
|
|
continue
|
|
capture = bpf_p.match(self.line)
|
|
if capture:
|
|
bpf_cmd_str += self.line
|
|
else:
|
|
break
|
|
self.line = self.reader.readline()
|
|
# Find the number of occurences of BPF\w+
|
|
self.enum_syscalls = re.findall('(BPF\w+)+', bpf_cmd_str)
|
|
|
|
def parse_desc_helpers(self):
|
|
self.seek_to('* Start of BPF helper function descriptions:',
|
|
'Could not find start of eBPF helper descriptions list')
|
|
while True:
|
|
try:
|
|
helper = self.parse_helper()
|
|
self.helpers.append(helper)
|
|
proto = helper.proto_break_down()
|
|
self.desc_unique_helpers.add(proto['name'])
|
|
except NoHelperFound:
|
|
break
|
|
|
|
def parse_define_helpers(self):
|
|
# Parse the number of FN(...) in #define __BPF_FUNC_MAPPER to compare
|
|
# later with the number of unique function names present in description.
|
|
# Note: seek_to(..) discards the first line below the target search text,
|
|
# resulting in FN(unspec) being skipped and not added to self.define_unique_helpers.
|
|
self.seek_to('#define __BPF_FUNC_MAPPER(FN)',
|
|
'Could not find start of eBPF helper definition list')
|
|
# Searches for either one or more FN(\w+) defines or a backslash for newline
|
|
p = re.compile('\s*(FN\(\w+\))+|\\\\')
|
|
fn_defines_str = ''
|
|
while True:
|
|
capture = p.match(self.line)
|
|
if capture:
|
|
fn_defines_str += self.line
|
|
else:
|
|
break
|
|
self.line = self.reader.readline()
|
|
# Find the number of occurences of FN(\w+)
|
|
self.define_unique_helpers = re.findall('FN\(\w+\)', fn_defines_str)
|
|
|
|
def run(self):
|
|
self.parse_desc_syscall()
|
|
self.parse_enum_syscall()
|
|
self.parse_desc_helpers()
|
|
self.parse_define_helpers()
|
|
self.reader.close()
|
|
|
|
###############################################################################
|
|
|
|
class Printer(object):
|
|
"""
|
|
A generic class for printers. Printers should be created with an array of
|
|
Helper objects, and implement a way to print them in the desired fashion.
|
|
@parser: A HeaderParser with objects to print to standard output
|
|
"""
|
|
def __init__(self, parser):
|
|
self.parser = parser
|
|
self.elements = []
|
|
|
|
def print_header(self):
|
|
pass
|
|
|
|
def print_footer(self):
|
|
pass
|
|
|
|
def print_one(self, helper):
|
|
pass
|
|
|
|
def print_all(self):
|
|
self.print_header()
|
|
for elem in self.elements:
|
|
self.print_one(elem)
|
|
self.print_footer()
|
|
|
|
def elem_number_check(self, desc_unique_elem, define_unique_elem, type, instance):
|
|
"""
|
|
Checks the number of helpers/syscalls documented within the header file
|
|
description with those defined as part of enum/macro and raise an
|
|
Exception if they don't match.
|
|
"""
|
|
nr_desc_unique_elem = len(desc_unique_elem)
|
|
nr_define_unique_elem = len(define_unique_elem)
|
|
if nr_desc_unique_elem != nr_define_unique_elem:
|
|
exception_msg = '''
|
|
The number of unique %s in description (%d) doesn\'t match the number of unique %s defined in %s (%d)
|
|
''' % (type, nr_desc_unique_elem, type, instance, nr_define_unique_elem)
|
|
if nr_desc_unique_elem < nr_define_unique_elem:
|
|
# Function description is parsed until no helper is found (which can be due to
|
|
# misformatting). Hence, only print the first missing/misformatted helper/enum.
|
|
exception_msg += '''
|
|
The description for %s is not present or formatted correctly.
|
|
''' % (define_unique_elem[nr_desc_unique_elem])
|
|
raise Exception(exception_msg)
|
|
|
|
class PrinterRST(Printer):
|
|
"""
|
|
A generic class for printers that print ReStructured Text. Printers should
|
|
be created with a HeaderParser object, and implement a way to print API
|
|
elements in the desired fashion.
|
|
@parser: A HeaderParser with objects to print to standard output
|
|
"""
|
|
def __init__(self, parser):
|
|
self.parser = parser
|
|
|
|
def print_license(self):
|
|
license = '''\
|
|
.. Copyright (C) All BPF authors and contributors from 2014 to present.
|
|
.. See git log include/uapi/linux/bpf.h in kernel tree for details.
|
|
..
|
|
.. %%%LICENSE_START(VERBATIM)
|
|
.. Permission is granted to make and distribute verbatim copies of this
|
|
.. manual provided the copyright notice and this permission notice are
|
|
.. preserved on all copies.
|
|
..
|
|
.. Permission is granted to copy and distribute modified versions of this
|
|
.. manual under the conditions for verbatim copying, provided that the
|
|
.. entire resulting derived work is distributed under the terms of a
|
|
.. permission notice identical to this one.
|
|
..
|
|
.. Since the Linux kernel and libraries are constantly changing, this
|
|
.. manual page may be incorrect or out-of-date. The author(s) assume no
|
|
.. responsibility for errors or omissions, or for damages resulting from
|
|
.. the use of the information contained herein. The author(s) may not
|
|
.. have taken the same level of care in the production of this manual,
|
|
.. which is licensed free of charge, as they might when working
|
|
.. professionally.
|
|
..
|
|
.. Formatted or processed versions of this manual, if unaccompanied by
|
|
.. the source, must acknowledge the copyright and authors of this work.
|
|
.. %%%LICENSE_END
|
|
..
|
|
.. Please do not edit this file. It was generated from the documentation
|
|
.. located in file include/uapi/linux/bpf.h of the Linux kernel sources
|
|
.. (helpers description), and from scripts/bpf_doc.py in the same
|
|
.. repository (header and footer).
|
|
'''
|
|
print(license)
|
|
|
|
def print_elem(self, elem):
|
|
if (elem.desc):
|
|
print('\tDescription')
|
|
# Do not strip all newline characters: formatted code at the end of
|
|
# a section must be followed by a blank line.
|
|
for line in re.sub('\n$', '', elem.desc, count=1).split('\n'):
|
|
print('{}{}'.format('\t\t' if line else '', line))
|
|
|
|
if (elem.ret):
|
|
print('\tReturn')
|
|
for line in elem.ret.rstrip().split('\n'):
|
|
print('{}{}'.format('\t\t' if line else '', line))
|
|
|
|
print('')
|
|
|
|
class PrinterHelpersRST(PrinterRST):
|
|
"""
|
|
A printer for dumping collected information about helpers as a ReStructured
|
|
Text page compatible with the rst2man program, which can be used to
|
|
generate a manual page for the helpers.
|
|
@parser: A HeaderParser with Helper objects to print to standard output
|
|
"""
|
|
def __init__(self, parser):
|
|
self.elements = parser.helpers
|
|
self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER')
|
|
|
|
def print_header(self):
|
|
header = '''\
|
|
===========
|
|
BPF-HELPERS
|
|
===========
|
|
-------------------------------------------------------------------------------
|
|
list of eBPF helper functions
|
|
-------------------------------------------------------------------------------
|
|
|
|
:Manual section: 7
|
|
|
|
DESCRIPTION
|
|
===========
|
|
|
|
The extended Berkeley Packet Filter (eBPF) subsystem consists in programs
|
|
written in a pseudo-assembly language, then attached to one of the several
|
|
kernel hooks and run in reaction of specific events. This framework differs
|
|
from the older, "classic" BPF (or "cBPF") in several aspects, one of them being
|
|
the ability to call special functions (or "helpers") from within a program.
|
|
These functions are restricted to a white-list of helpers defined in the
|
|
kernel.
|
|
|
|
These helpers are used by eBPF programs to interact with the system, or with
|
|
the context in which they work. For instance, they can be used to print
|
|
debugging messages, to get the time since the system was booted, to interact
|
|
with eBPF maps, or to manipulate network packets. Since there are several eBPF
|
|
program types, and that they do not run in the same context, each program type
|
|
can only call a subset of those helpers.
|
|
|
|
Due to eBPF conventions, a helper can not have more than five arguments.
|
|
|
|
Internally, eBPF programs call directly into the compiled helper functions
|
|
without requiring any foreign-function interface. As a result, calling helpers
|
|
introduces no overhead, thus offering excellent performance.
|
|
|
|
This document is an attempt to list and document the helpers available to eBPF
|
|
developers. They are sorted by chronological order (the oldest helpers in the
|
|
kernel at the top).
|
|
|
|
HELPERS
|
|
=======
|
|
'''
|
|
PrinterRST.print_license(self)
|
|
print(header)
|
|
|
|
def print_footer(self):
|
|
footer = '''
|
|
EXAMPLES
|
|
========
|
|
|
|
Example usage for most of the eBPF helpers listed in this manual page are
|
|
available within the Linux kernel sources, at the following locations:
|
|
|
|
* *samples/bpf/*
|
|
* *tools/testing/selftests/bpf/*
|
|
|
|
LICENSE
|
|
=======
|
|
|
|
eBPF programs can have an associated license, passed along with the bytecode
|
|
instructions to the kernel when the programs are loaded. The format for that
|
|
string is identical to the one in use for kernel modules (Dual licenses, such
|
|
as "Dual BSD/GPL", may be used). Some helper functions are only accessible to
|
|
programs that are compatible with the GNU Privacy License (GPL).
|
|
|
|
In order to use such helpers, the eBPF program must be loaded with the correct
|
|
license string passed (via **attr**) to the **bpf**\ () system call, and this
|
|
generally translates into the C source code of the program containing a line
|
|
similar to the following:
|
|
|
|
::
|
|
|
|
char ____license[] __attribute__((section("license"), used)) = "GPL";
|
|
|
|
IMPLEMENTATION
|
|
==============
|
|
|
|
This manual page is an effort to document the existing eBPF helper functions.
|
|
But as of this writing, the BPF sub-system is under heavy development. New eBPF
|
|
program or map types are added, along with new helper functions. Some helpers
|
|
are occasionally made available for additional program types. So in spite of
|
|
the efforts of the community, this page might not be up-to-date. If you want to
|
|
check by yourself what helper functions exist in your kernel, or what types of
|
|
programs they can support, here are some files among the kernel tree that you
|
|
may be interested in:
|
|
|
|
* *include/uapi/linux/bpf.h* is the main BPF header. It contains the full list
|
|
of all helper functions, as well as many other BPF definitions including most
|
|
of the flags, structs or constants used by the helpers.
|
|
* *net/core/filter.c* contains the definition of most network-related helper
|
|
functions, and the list of program types from which they can be used.
|
|
* *kernel/trace/bpf_trace.c* is the equivalent for most tracing program-related
|
|
helpers.
|
|
* *kernel/bpf/verifier.c* contains the functions used to check that valid types
|
|
of eBPF maps are used with a given helper function.
|
|
* *kernel/bpf/* directory contains other files in which additional helpers are
|
|
defined (for cgroups, sockmaps, etc.).
|
|
* The bpftool utility can be used to probe the availability of helper functions
|
|
on the system (as well as supported program and map types, and a number of
|
|
other parameters). To do so, run **bpftool feature probe** (see
|
|
**bpftool-feature**\ (8) for details). Add the **unprivileged** keyword to
|
|
list features available to unprivileged users.
|
|
|
|
Compatibility between helper functions and program types can generally be found
|
|
in the files where helper functions are defined. Look for the **struct
|
|
bpf_func_proto** objects and for functions returning them: these functions
|
|
contain a list of helpers that a given program type can call. Note that the
|
|
**default:** label of the **switch ... case** used to filter helpers can call
|
|
other functions, themselves allowing access to additional helpers. The
|
|
requirement for GPL license is also in those **struct bpf_func_proto**.
|
|
|
|
Compatibility between helper functions and map types can be found in the
|
|
**check_map_func_compatibility**\ () function in file *kernel/bpf/verifier.c*.
|
|
|
|
Helper functions that invalidate the checks on **data** and **data_end**
|
|
pointers for network processing are listed in function
|
|
**bpf_helper_changes_pkt_data**\ () in file *net/core/filter.c*.
|
|
|
|
SEE ALSO
|
|
========
|
|
|
|
**bpf**\ (2),
|
|
**bpftool**\ (8),
|
|
**cgroups**\ (7),
|
|
**ip**\ (8),
|
|
**perf_event_open**\ (2),
|
|
**sendmsg**\ (2),
|
|
**socket**\ (7),
|
|
**tc-bpf**\ (8)'''
|
|
print(footer)
|
|
|
|
def print_proto(self, helper):
|
|
"""
|
|
Format function protocol with bold and italics markers. This makes RST
|
|
file less readable, but gives nice results in the manual page.
|
|
"""
|
|
proto = helper.proto_break_down()
|
|
|
|
print('**%s %s%s(' % (proto['ret_type'],
|
|
proto['ret_star'].replace('*', '\\*'),
|
|
proto['name']),
|
|
end='')
|
|
|
|
comma = ''
|
|
for a in proto['args']:
|
|
one_arg = '{}{}'.format(comma, a['type'])
|
|
if a['name']:
|
|
if a['star']:
|
|
one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*'))
|
|
else:
|
|
one_arg += '** '
|
|
one_arg += '*{}*\\ **'.format(a['name'])
|
|
comma = ', '
|
|
print(one_arg, end='')
|
|
|
|
print(')**')
|
|
|
|
def print_one(self, helper):
|
|
self.print_proto(helper)
|
|
self.print_elem(helper)
|
|
|
|
|
|
class PrinterSyscallRST(PrinterRST):
|
|
"""
|
|
A printer for dumping collected information about the syscall API as a
|
|
ReStructured Text page compatible with the rst2man program, which can be
|
|
used to generate a manual page for the syscall.
|
|
@parser: A HeaderParser with APIElement objects to print to standard
|
|
output
|
|
"""
|
|
def __init__(self, parser):
|
|
self.elements = parser.commands
|
|
self.elem_number_check(parser.desc_syscalls, parser.enum_syscalls, 'syscall', 'bpf_cmd')
|
|
|
|
def print_header(self):
|
|
header = '''\
|
|
===
|
|
bpf
|
|
===
|
|
-------------------------------------------------------------------------------
|
|
Perform a command on an extended BPF object
|
|
-------------------------------------------------------------------------------
|
|
|
|
:Manual section: 2
|
|
|
|
COMMANDS
|
|
========
|
|
'''
|
|
PrinterRST.print_license(self)
|
|
print(header)
|
|
|
|
def print_one(self, command):
|
|
print('**%s**' % (command.proto))
|
|
self.print_elem(command)
|
|
|
|
|
|
class PrinterHelpers(Printer):
|
|
"""
|
|
A printer for dumping collected information about helpers as C header to
|
|
be included from BPF program.
|
|
@parser: A HeaderParser with Helper objects to print to standard output
|
|
"""
|
|
def __init__(self, parser):
|
|
self.elements = parser.helpers
|
|
self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER')
|
|
|
|
type_fwds = [
|
|
'struct bpf_fib_lookup',
|
|
'struct bpf_sk_lookup',
|
|
'struct bpf_perf_event_data',
|
|
'struct bpf_perf_event_value',
|
|
'struct bpf_pidns_info',
|
|
'struct bpf_redir_neigh',
|
|
'struct bpf_sock',
|
|
'struct bpf_sock_addr',
|
|
'struct bpf_sock_ops',
|
|
'struct bpf_sock_tuple',
|
|
'struct bpf_spin_lock',
|
|
'struct bpf_sysctl',
|
|
'struct bpf_tcp_sock',
|
|
'struct bpf_tunnel_key',
|
|
'struct bpf_xfrm_state',
|
|
'struct linux_binprm',
|
|
'struct pt_regs',
|
|
'struct sk_reuseport_md',
|
|
'struct sockaddr',
|
|
'struct tcphdr',
|
|
'struct seq_file',
|
|
'struct tcp6_sock',
|
|
'struct tcp_sock',
|
|
'struct tcp_timewait_sock',
|
|
'struct tcp_request_sock',
|
|
'struct udp6_sock',
|
|
'struct unix_sock',
|
|
'struct task_struct',
|
|
|
|
'struct __sk_buff',
|
|
'struct sk_msg_md',
|
|
'struct xdp_md',
|
|
'struct path',
|
|
'struct btf_ptr',
|
|
'struct inode',
|
|
'struct socket',
|
|
'struct file',
|
|
'struct bpf_timer',
|
|
'struct mptcp_sock',
|
|
'struct bpf_dynptr',
|
|
]
|
|
known_types = {
|
|
'...',
|
|
'void',
|
|
'const void',
|
|
'char',
|
|
'const char',
|
|
'int',
|
|
'long',
|
|
'unsigned long',
|
|
|
|
'__be16',
|
|
'__be32',
|
|
'__wsum',
|
|
|
|
'struct bpf_fib_lookup',
|
|
'struct bpf_perf_event_data',
|
|
'struct bpf_perf_event_value',
|
|
'struct bpf_pidns_info',
|
|
'struct bpf_redir_neigh',
|
|
'struct bpf_sk_lookup',
|
|
'struct bpf_sock',
|
|
'struct bpf_sock_addr',
|
|
'struct bpf_sock_ops',
|
|
'struct bpf_sock_tuple',
|
|
'struct bpf_spin_lock',
|
|
'struct bpf_sysctl',
|
|
'struct bpf_tcp_sock',
|
|
'struct bpf_tunnel_key',
|
|
'struct bpf_xfrm_state',
|
|
'struct linux_binprm',
|
|
'struct pt_regs',
|
|
'struct sk_reuseport_md',
|
|
'struct sockaddr',
|
|
'struct tcphdr',
|
|
'struct seq_file',
|
|
'struct tcp6_sock',
|
|
'struct tcp_sock',
|
|
'struct tcp_timewait_sock',
|
|
'struct tcp_request_sock',
|
|
'struct udp6_sock',
|
|
'struct unix_sock',
|
|
'struct task_struct',
|
|
'struct path',
|
|
'struct btf_ptr',
|
|
'struct inode',
|
|
'struct socket',
|
|
'struct file',
|
|
'struct bpf_timer',
|
|
'struct mptcp_sock',
|
|
'struct bpf_dynptr',
|
|
}
|
|
mapped_types = {
|
|
'u8': '__u8',
|
|
'u16': '__u16',
|
|
'u32': '__u32',
|
|
'u64': '__u64',
|
|
's8': '__s8',
|
|
's16': '__s16',
|
|
's32': '__s32',
|
|
's64': '__s64',
|
|
'size_t': 'unsigned long',
|
|
'struct bpf_map': 'void',
|
|
'struct sk_buff': 'struct __sk_buff',
|
|
'const struct sk_buff': 'const struct __sk_buff',
|
|
'struct sk_msg_buff': 'struct sk_msg_md',
|
|
'struct xdp_buff': 'struct xdp_md',
|
|
}
|
|
# Helpers overloaded for different context types.
|
|
overloaded_helpers = [
|
|
'bpf_get_socket_cookie',
|
|
'bpf_sk_assign',
|
|
]
|
|
|
|
def print_header(self):
|
|
header = '''\
|
|
/* This is auto-generated file. See bpf_doc.py for details. */
|
|
|
|
/* Forward declarations of BPF structs */'''
|
|
|
|
print(header)
|
|
for fwd in self.type_fwds:
|
|
print('%s;' % fwd)
|
|
print('')
|
|
|
|
def print_footer(self):
|
|
footer = ''
|
|
print(footer)
|
|
|
|
def map_type(self, t):
|
|
if t in self.known_types:
|
|
return t
|
|
if t in self.mapped_types:
|
|
return self.mapped_types[t]
|
|
print("Unrecognized type '%s', please add it to known types!" % t,
|
|
file=sys.stderr)
|
|
sys.exit(1)
|
|
|
|
seen_helpers = set()
|
|
|
|
def print_one(self, helper):
|
|
proto = helper.proto_break_down()
|
|
|
|
if proto['name'] in self.seen_helpers:
|
|
return
|
|
self.seen_helpers.add(proto['name'])
|
|
|
|
print('/*')
|
|
print(" * %s" % proto['name'])
|
|
print(" *")
|
|
if (helper.desc):
|
|
# Do not strip all newline characters: formatted code at the end of
|
|
# a section must be followed by a blank line.
|
|
for line in re.sub('\n$', '', helper.desc, count=1).split('\n'):
|
|
print(' *{}{}'.format(' \t' if line else '', line))
|
|
|
|
if (helper.ret):
|
|
print(' *')
|
|
print(' * Returns')
|
|
for line in helper.ret.rstrip().split('\n'):
|
|
print(' *{}{}'.format(' \t' if line else '', line))
|
|
|
|
print(' */')
|
|
print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']),
|
|
proto['ret_star'], proto['name']), end='')
|
|
comma = ''
|
|
for i, a in enumerate(proto['args']):
|
|
t = a['type']
|
|
n = a['name']
|
|
if proto['name'] in self.overloaded_helpers and i == 0:
|
|
t = 'void'
|
|
n = 'ctx'
|
|
one_arg = '{}{}'.format(comma, self.map_type(t))
|
|
if n:
|
|
if a['star']:
|
|
one_arg += ' {}'.format(a['star'])
|
|
else:
|
|
one_arg += ' '
|
|
one_arg += '{}'.format(n)
|
|
comma = ', '
|
|
print(one_arg, end='')
|
|
|
|
print(') = (void *) %d;' % len(self.seen_helpers))
|
|
print('')
|
|
|
|
###############################################################################
|
|
|
|
# If script is launched from scripts/ from kernel tree and can access
|
|
# ../include/uapi/linux/bpf.h, use it as a default name for the file to parse,
|
|
# otherwise the --filename argument will be required from the command line.
|
|
script = os.path.abspath(sys.argv[0])
|
|
linuxRoot = os.path.dirname(os.path.dirname(script))
|
|
bpfh = os.path.join(linuxRoot, 'include/uapi/linux/bpf.h')
|
|
|
|
printers = {
|
|
'helpers': PrinterHelpersRST,
|
|
'syscall': PrinterSyscallRST,
|
|
}
|
|
|
|
argParser = argparse.ArgumentParser(description="""
|
|
Parse eBPF header file and generate documentation for the eBPF API.
|
|
The RST-formatted output produced can be turned into a manual page with the
|
|
rst2man utility.
|
|
""")
|
|
argParser.add_argument('--header', action='store_true',
|
|
help='generate C header file')
|
|
if (os.path.isfile(bpfh)):
|
|
argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h',
|
|
default=bpfh)
|
|
else:
|
|
argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h')
|
|
argParser.add_argument('target', nargs='?', default='helpers',
|
|
choices=printers.keys(), help='eBPF API target')
|
|
args = argParser.parse_args()
|
|
|
|
# Parse file.
|
|
headerParser = HeaderParser(args.filename)
|
|
headerParser.run()
|
|
|
|
# Print formatted output to standard output.
|
|
if args.header:
|
|
if args.target != 'helpers':
|
|
raise NotImplementedError('Only helpers header generation is supported')
|
|
printer = PrinterHelpers(headerParser)
|
|
else:
|
|
printer = printers[args.target](headerParser)
|
|
printer.print_all()
|