894 lines
32 KiB
Python
Executable File
894 lines
32 KiB
Python
Executable File
#!/usr/bin/env python3
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# SPDX-License-Identifier: GPL-2.0-only
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#
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# Copyright (C) 2018-2019 Netronome Systems, Inc.
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# Copyright (C) 2021 Isovalent, Inc.
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# In case user attempts to run with Python 2.
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from __future__ import print_function
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import argparse
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import re
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import sys, os
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import subprocess
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helpersDocStart = 'Start of BPF helper function descriptions:'
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class NoHelperFound(BaseException):
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pass
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class NoSyscallCommandFound(BaseException):
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pass
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class ParsingError(BaseException):
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def __init__(self, line='<line not provided>', reader=None):
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if reader:
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BaseException.__init__(self,
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'Error at file offset %d, parsing line: %s' %
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(reader.tell(), line))
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else:
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BaseException.__init__(self, 'Error parsing line: %s' % line)
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class APIElement(object):
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"""
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An object representing the description of an aspect of the eBPF API.
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@proto: prototype of the API symbol
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@desc: textual description of the symbol
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@ret: (optional) description of any associated return value
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"""
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def __init__(self, proto='', desc='', ret=''):
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self.proto = proto
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self.desc = desc
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self.ret = ret
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class Helper(APIElement):
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"""
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An object representing the description of an eBPF helper function.
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@proto: function prototype of the helper function
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@desc: textual description of the helper function
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@ret: description of the return value of the helper function
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"""
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def __init__(self, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.enum_val = None
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def proto_break_down(self):
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"""
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Break down helper function protocol into smaller chunks: return type,
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name, distincts arguments.
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"""
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arg_re = re.compile(r'((\w+ )*?(\w+|...))( (\**)(\w+))?$')
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res = {}
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proto_re = re.compile(r'(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$')
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capture = proto_re.match(self.proto)
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res['ret_type'] = capture.group(1)
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res['ret_star'] = capture.group(2)
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res['name'] = capture.group(3)
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res['args'] = []
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args = capture.group(4).split(', ')
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for a in args:
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capture = arg_re.match(a)
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res['args'].append({
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'type' : capture.group(1),
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'star' : capture.group(5),
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'name' : capture.group(6)
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})
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return res
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class HeaderParser(object):
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"""
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An object used to parse a file in order to extract the documentation of a
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list of eBPF helper functions. All the helpers that can be retrieved are
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stored as Helper object, in the self.helpers() array.
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@filename: name of file to parse, usually include/uapi/linux/bpf.h in the
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kernel tree
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"""
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def __init__(self, filename):
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self.reader = open(filename, 'r')
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self.line = ''
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self.helpers = []
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self.commands = []
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self.desc_unique_helpers = set()
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self.define_unique_helpers = []
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self.helper_enum_vals = {}
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self.helper_enum_pos = {}
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self.desc_syscalls = []
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self.enum_syscalls = []
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def parse_element(self):
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proto = self.parse_symbol()
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desc = self.parse_desc(proto)
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ret = self.parse_ret(proto)
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return APIElement(proto=proto, desc=desc, ret=ret)
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def parse_helper(self):
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proto = self.parse_proto()
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desc = self.parse_desc(proto)
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ret = self.parse_ret(proto)
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return Helper(proto=proto, desc=desc, ret=ret)
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def parse_symbol(self):
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p = re.compile(r' \* ?(BPF\w+)$')
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capture = p.match(self.line)
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if not capture:
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raise NoSyscallCommandFound
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end_re = re.compile(r' \* ?NOTES$')
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end = end_re.match(self.line)
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if end:
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raise NoSyscallCommandFound
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self.line = self.reader.readline()
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return capture.group(1)
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def parse_proto(self):
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# Argument can be of shape:
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# - "void"
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# - "type name"
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# - "type *name"
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# - Same as above, with "const" and/or "struct" in front of type
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# - "..." (undefined number of arguments, for bpf_trace_printk())
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# There is at least one term ("void"), and at most five arguments.
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p = re.compile(r' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$')
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capture = p.match(self.line)
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if not capture:
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raise NoHelperFound
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self.line = self.reader.readline()
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return capture.group(1)
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def parse_desc(self, proto):
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p = re.compile(r' \* ?(?:\t| {5,8})Description$')
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capture = p.match(self.line)
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if not capture:
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raise Exception("No description section found for " + proto)
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# Description can be several lines, some of them possibly empty, and it
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# stops when another subsection title is met.
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desc = ''
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desc_present = False
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while True:
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self.line = self.reader.readline()
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if self.line == ' *\n':
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desc += '\n'
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else:
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p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
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capture = p.match(self.line)
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if capture:
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desc_present = True
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desc += capture.group(1) + '\n'
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else:
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break
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if not desc_present:
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raise Exception("No description found for " + proto)
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return desc
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def parse_ret(self, proto):
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p = re.compile(r' \* ?(?:\t| {5,8})Return$')
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capture = p.match(self.line)
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if not capture:
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raise Exception("No return section found for " + proto)
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# Return value description can be several lines, some of them possibly
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# empty, and it stops when another subsection title is met.
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ret = ''
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ret_present = False
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while True:
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self.line = self.reader.readline()
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if self.line == ' *\n':
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ret += '\n'
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else:
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p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)')
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capture = p.match(self.line)
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if capture:
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ret_present = True
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ret += capture.group(1) + '\n'
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else:
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break
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if not ret_present:
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raise Exception("No return found for " + proto)
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return ret
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def seek_to(self, target, help_message, discard_lines = 1):
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self.reader.seek(0)
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offset = self.reader.read().find(target)
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if offset == -1:
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raise Exception(help_message)
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self.reader.seek(offset)
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self.reader.readline()
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for _ in range(discard_lines):
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self.reader.readline()
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self.line = self.reader.readline()
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def parse_desc_syscall(self):
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self.seek_to('* DOC: eBPF Syscall Commands',
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'Could not find start of eBPF syscall descriptions list')
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while True:
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try:
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command = self.parse_element()
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self.commands.append(command)
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self.desc_syscalls.append(command.proto)
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except NoSyscallCommandFound:
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break
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def parse_enum_syscall(self):
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self.seek_to('enum bpf_cmd {',
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'Could not find start of bpf_cmd enum', 0)
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# Searches for either one or more BPF\w+ enums
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bpf_p = re.compile(r'\s*(BPF\w+)+')
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# Searches for an enum entry assigned to another entry,
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# for e.g. BPF_PROG_RUN = BPF_PROG_TEST_RUN, which is
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# not documented hence should be skipped in check to
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# determine if the right number of syscalls are documented
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assign_p = re.compile(r'\s*(BPF\w+)\s*=\s*(BPF\w+)')
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bpf_cmd_str = ''
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while True:
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capture = assign_p.match(self.line)
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if capture:
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# Skip line if an enum entry is assigned to another entry
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self.line = self.reader.readline()
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continue
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capture = bpf_p.match(self.line)
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if capture:
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bpf_cmd_str += self.line
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else:
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break
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self.line = self.reader.readline()
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# Find the number of occurences of BPF\w+
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self.enum_syscalls = re.findall(r'(BPF\w+)+', bpf_cmd_str)
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def parse_desc_helpers(self):
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self.seek_to(helpersDocStart,
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'Could not find start of eBPF helper descriptions list')
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while True:
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try:
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helper = self.parse_helper()
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self.helpers.append(helper)
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proto = helper.proto_break_down()
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self.desc_unique_helpers.add(proto['name'])
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except NoHelperFound:
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break
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def parse_define_helpers(self):
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# Parse FN(...) in #define ___BPF_FUNC_MAPPER to compare later with the
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# number of unique function names present in description and use the
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# correct enumeration value.
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# Note: seek_to(..) discards the first line below the target search text,
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# resulting in FN(unspec, 0, ##ctx) being skipped and not added to
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# self.define_unique_helpers.
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self.seek_to('#define ___BPF_FUNC_MAPPER(FN, ctx...)',
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'Could not find start of eBPF helper definition list')
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# Searches for one FN(\w+) define or a backslash for newline
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p = re.compile(r'\s*FN\((\w+), (\d+), ##ctx\)|\\\\')
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fn_defines_str = ''
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i = 0
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while True:
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capture = p.match(self.line)
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if capture:
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fn_defines_str += self.line
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helper_name = capture.expand(r'bpf_\1')
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self.helper_enum_vals[helper_name] = int(capture.group(2))
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self.helper_enum_pos[helper_name] = i
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i += 1
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else:
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break
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self.line = self.reader.readline()
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# Find the number of occurences of FN(\w+)
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self.define_unique_helpers = re.findall(r'FN\(\w+, \d+, ##ctx\)', fn_defines_str)
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def validate_helpers(self):
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last_helper = ''
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seen_helpers = set()
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seen_enum_vals = set()
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i = 0
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for helper in self.helpers:
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proto = helper.proto_break_down()
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name = proto['name']
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try:
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enum_val = self.helper_enum_vals[name]
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enum_pos = self.helper_enum_pos[name]
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except KeyError:
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raise Exception("Helper %s is missing from enum bpf_func_id" % name)
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if name in seen_helpers:
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if last_helper != name:
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raise Exception("Helper %s has multiple descriptions which are not grouped together" % name)
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continue
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# Enforce current practice of having the descriptions ordered
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# by enum value.
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if enum_pos != i:
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raise Exception("Helper %s (ID %d) comment order (#%d) must be aligned with its position (#%d) in enum bpf_func_id" % (name, enum_val, i + 1, enum_pos + 1))
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if enum_val in seen_enum_vals:
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raise Exception("Helper %s has duplicated value %d" % (name, enum_val))
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seen_helpers.add(name)
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last_helper = name
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seen_enum_vals.add(enum_val)
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helper.enum_val = enum_val
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i += 1
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def run(self):
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self.parse_desc_syscall()
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self.parse_enum_syscall()
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self.parse_desc_helpers()
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self.parse_define_helpers()
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self.validate_helpers()
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self.reader.close()
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###############################################################################
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class Printer(object):
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"""
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A generic class for printers. Printers should be created with an array of
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Helper objects, and implement a way to print them in the desired fashion.
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@parser: A HeaderParser with objects to print to standard output
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"""
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def __init__(self, parser):
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self.parser = parser
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self.elements = []
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def print_header(self):
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pass
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def print_footer(self):
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pass
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def print_one(self, helper):
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pass
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def print_all(self):
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self.print_header()
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for elem in self.elements:
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self.print_one(elem)
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self.print_footer()
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def elem_number_check(self, desc_unique_elem, define_unique_elem, type, instance):
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"""
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Checks the number of helpers/syscalls documented within the header file
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description with those defined as part of enum/macro and raise an
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Exception if they don't match.
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"""
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nr_desc_unique_elem = len(desc_unique_elem)
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nr_define_unique_elem = len(define_unique_elem)
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if nr_desc_unique_elem != nr_define_unique_elem:
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exception_msg = '''
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The number of unique %s in description (%d) doesn\'t match the number of unique %s defined in %s (%d)
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''' % (type, nr_desc_unique_elem, type, instance, nr_define_unique_elem)
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if nr_desc_unique_elem < nr_define_unique_elem:
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# Function description is parsed until no helper is found (which can be due to
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# misformatting). Hence, only print the first missing/misformatted helper/enum.
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exception_msg += '''
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The description for %s is not present or formatted correctly.
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''' % (define_unique_elem[nr_desc_unique_elem])
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raise Exception(exception_msg)
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class PrinterRST(Printer):
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"""
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A generic class for printers that print ReStructured Text. Printers should
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be created with a HeaderParser object, and implement a way to print API
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elements in the desired fashion.
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@parser: A HeaderParser with objects to print to standard output
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"""
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def __init__(self, parser):
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self.parser = parser
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def print_license(self):
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license = '''\
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.. Copyright (C) All BPF authors and contributors from 2014 to present.
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.. See git log include/uapi/linux/bpf.h in kernel tree for details.
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..
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.. SPDX-License-Identifier: Linux-man-pages-copyleft
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..
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.. Please do not edit this file. It was generated from the documentation
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.. located in file include/uapi/linux/bpf.h of the Linux kernel sources
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.. (helpers description), and from scripts/bpf_doc.py in the same
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.. repository (header and footer).
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'''
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print(license)
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def print_elem(self, elem):
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if (elem.desc):
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print('\tDescription')
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# Do not strip all newline characters: formatted code at the end of
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# a section must be followed by a blank line.
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for line in re.sub('\n$', '', elem.desc, count=1).split('\n'):
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print('{}{}'.format('\t\t' if line else '', line))
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if (elem.ret):
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print('\tReturn')
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for line in elem.ret.rstrip().split('\n'):
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print('{}{}'.format('\t\t' if line else '', line))
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print('')
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def get_kernel_version(self):
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try:
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version = subprocess.run(['git', 'describe'], cwd=linuxRoot,
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capture_output=True, check=True)
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version = version.stdout.decode().rstrip()
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except:
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try:
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version = subprocess.run(['make', '-s', '--no-print-directory', 'kernelversion'],
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cwd=linuxRoot, capture_output=True, check=True)
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version = version.stdout.decode().rstrip()
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except:
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return 'Linux'
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return 'Linux {version}'.format(version=version)
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def get_last_doc_update(self, delimiter):
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try:
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cmd = ['git', 'log', '-1', '--pretty=format:%cs', '--no-patch',
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'-L',
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'/{}/,/\\*\\//:include/uapi/linux/bpf.h'.format(delimiter)]
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date = subprocess.run(cmd, cwd=linuxRoot,
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capture_output=True, check=True)
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return date.stdout.decode().rstrip()
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except:
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return ''
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class PrinterHelpersRST(PrinterRST):
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"""
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A printer for dumping collected information about helpers as a ReStructured
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Text page compatible with the rst2man program, which can be used to
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generate a manual page for the helpers.
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@parser: A HeaderParser with Helper objects to print to standard output
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"""
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def __init__(self, parser):
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self.elements = parser.helpers
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self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '___BPF_FUNC_MAPPER')
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def print_header(self):
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header = '''\
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===========
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BPF-HELPERS
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===========
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-------------------------------------------------------------------------------
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list of eBPF helper functions
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-------------------------------------------------------------------------------
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:Manual section: 7
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:Version: {version}
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{date_field}{date}
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DESCRIPTION
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===========
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The extended Berkeley Packet Filter (eBPF) subsystem consists in programs
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written in a pseudo-assembly language, then attached to one of the several
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kernel hooks and run in reaction of specific events. This framework differs
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from the older, "classic" BPF (or "cBPF") in several aspects, one of them being
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the ability to call special functions (or "helpers") from within a program.
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These functions are restricted to a white-list of helpers defined in the
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kernel.
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These helpers are used by eBPF programs to interact with the system, or with
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the context in which they work. For instance, they can be used to print
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debugging messages, to get the time since the system was booted, to interact
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with eBPF maps, or to manipulate network packets. Since there are several eBPF
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program types, and that they do not run in the same context, each program type
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can only call a subset of those helpers.
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Due to eBPF conventions, a helper can not have more than five arguments.
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Internally, eBPF programs call directly into the compiled helper functions
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without requiring any foreign-function interface. As a result, calling helpers
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introduces no overhead, thus offering excellent performance.
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This document is an attempt to list and document the helpers available to eBPF
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developers. They are sorted by chronological order (the oldest helpers in the
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kernel at the top).
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HELPERS
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=======
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'''
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kernelVersion = self.get_kernel_version()
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lastUpdate = self.get_last_doc_update(helpersDocStart)
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PrinterRST.print_license(self)
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print(header.format(version=kernelVersion,
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date_field = ':Date: ' if lastUpdate else '',
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date=lastUpdate))
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def print_footer(self):
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footer = '''
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EXAMPLES
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========
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Example usage for most of the eBPF helpers listed in this manual page are
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|
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 General Public License (GNU 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 cgroup',
|
|
|
|
'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',
|
|
'struct iphdr',
|
|
'struct ipv6hdr',
|
|
]
|
|
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 cgroup',
|
|
'struct path',
|
|
'struct btf_ptr',
|
|
'struct inode',
|
|
'struct socket',
|
|
'struct file',
|
|
'struct bpf_timer',
|
|
'struct mptcp_sock',
|
|
'struct bpf_dynptr',
|
|
'const struct bpf_dynptr',
|
|
'struct iphdr',
|
|
'struct ipv6hdr',
|
|
}
|
|
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;' % helper.enum_val)
|
|
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()
|