| #!/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 |
| import subprocess |
| |
| helpersDocStart = 'Start of BPF helper function descriptions:' |
| |
| 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 __init__(self, *args, **kwargs): |
| super().__init__(*args, **kwargs) |
| self.enum_val = None |
| |
| def proto_break_down(self): |
| """ |
| Break down helper function protocol into smaller chunks: return type, |
| name, distincts arguments. |
| """ |
| arg_re = re.compile(r'((\w+ )*?(\w+|...))( (\**)(\w+))?$') |
| res = {} |
| proto_re = re.compile(r'(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') |
| |
| capture = proto_re.match(self.proto) |
| res['ret_type'] = capture.group(1) |
| res['ret_star'] = capture.group(2) |
| res['name'] = capture.group(3) |
| res['args'] = [] |
| |
| args = capture.group(4).split(', ') |
| for a in args: |
| capture = arg_re.match(a) |
| res['args'].append({ |
| 'type' : capture.group(1), |
| 'star' : capture.group(5), |
| 'name' : capture.group(6) |
| }) |
| |
| return res |
| |
| |
| class HeaderParser(object): |
| """ |
| An object used to parse a file in order to extract the documentation of a |
| list of eBPF helper functions. All the helpers that can be retrieved are |
| stored as Helper object, in the self.helpers() array. |
| @filename: name of file to parse, usually include/uapi/linux/bpf.h in the |
| kernel tree |
| """ |
| def __init__(self, filename): |
| self.reader = open(filename, 'r') |
| self.line = '' |
| self.helpers = [] |
| self.commands = [] |
| self.desc_unique_helpers = set() |
| self.define_unique_helpers = [] |
| self.helper_enum_vals = {} |
| self.helper_enum_pos = {} |
| self.desc_syscalls = [] |
| self.enum_syscalls = [] |
| |
| def parse_element(self): |
| proto = self.parse_symbol() |
| desc = self.parse_desc(proto) |
| ret = self.parse_ret(proto) |
| return APIElement(proto=proto, desc=desc, ret=ret) |
| |
| def parse_helper(self): |
| proto = self.parse_proto() |
| desc = self.parse_desc(proto) |
| ret = self.parse_ret(proto) |
| return Helper(proto=proto, desc=desc, ret=ret) |
| |
| def parse_symbol(self): |
| p = re.compile(r' \* ?(BPF\w+)$') |
| capture = p.match(self.line) |
| if not capture: |
| raise NoSyscallCommandFound |
| end_re = re.compile(r' \* ?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(r' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') |
| capture = p.match(self.line) |
| if not capture: |
| raise NoHelperFound |
| self.line = self.reader.readline() |
| return capture.group(1) |
| |
| def parse_desc(self, proto): |
| p = re.compile(r' \* ?(?:\t| {5,8})Description$') |
| 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(r' \* ?(?:\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(r' \* ?(?:\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(r' \* ?(?:\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(r'\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(r'\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(r'(BPF\w+)+', bpf_cmd_str) |
| |
| def parse_desc_helpers(self): |
| self.seek_to(helpersDocStart, |
| '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 FN(...) in #define ___BPF_FUNC_MAPPER to compare later with the |
| # number of unique function names present in description and use the |
| # correct enumeration value. |
| # Note: seek_to(..) discards the first line below the target search text, |
| # resulting in FN(unspec, 0, ##ctx) being skipped and not added to |
| # self.define_unique_helpers. |
| self.seek_to('#define ___BPF_FUNC_MAPPER(FN, ctx...)', |
| 'Could not find start of eBPF helper definition list') |
| # Searches for one FN(\w+) define or a backslash for newline |
| p = re.compile(r'\s*FN\((\w+), (\d+), ##ctx\)|\\\\') |
| fn_defines_str = '' |
| i = 0 |
| while True: |
| capture = p.match(self.line) |
| if capture: |
| fn_defines_str += self.line |
| helper_name = capture.expand(r'bpf_\1') |
| self.helper_enum_vals[helper_name] = int(capture.group(2)) |
| self.helper_enum_pos[helper_name] = i |
| i += 1 |
| else: |
| break |
| self.line = self.reader.readline() |
| # Find the number of occurences of FN(\w+) |
| self.define_unique_helpers = re.findall(r'FN\(\w+, \d+, ##ctx\)', fn_defines_str) |
| |
| def validate_helpers(self): |
| last_helper = '' |
| seen_helpers = set() |
| seen_enum_vals = set() |
| i = 0 |
| for helper in self.helpers: |
| proto = helper.proto_break_down() |
| name = proto['name'] |
| try: |
| enum_val = self.helper_enum_vals[name] |
| enum_pos = self.helper_enum_pos[name] |
| except KeyError: |
| raise Exception("Helper %s is missing from enum bpf_func_id" % name) |
| |
| if name in seen_helpers: |
| if last_helper != name: |
| raise Exception("Helper %s has multiple descriptions which are not grouped together" % name) |
| continue |
| |
| # Enforce current practice of having the descriptions ordered |
| # by enum value. |
| if enum_pos != i: |
| 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)) |
| if enum_val in seen_enum_vals: |
| raise Exception("Helper %s has duplicated value %d" % (name, enum_val)) |
| |
| seen_helpers.add(name) |
| last_helper = name |
| seen_enum_vals.add(enum_val) |
| |
| helper.enum_val = enum_val |
| i += 1 |
| |
| def run(self): |
| self.parse_desc_syscall() |
| self.parse_enum_syscall() |
| self.parse_desc_helpers() |
| self.parse_define_helpers() |
| self.validate_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. |
| .. |
| .. SPDX-License-Identifier: Linux-man-pages-copyleft |
| .. |
| .. 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('') |
| |
| def get_kernel_version(self): |
| try: |
| version = subprocess.run(['git', 'describe'], cwd=linuxRoot, |
| capture_output=True, check=True) |
| version = version.stdout.decode().rstrip() |
| except: |
| try: |
| version = subprocess.run(['make', '-s', '--no-print-directory', 'kernelversion'], |
| cwd=linuxRoot, capture_output=True, check=True) |
| version = version.stdout.decode().rstrip() |
| except: |
| return 'Linux' |
| return 'Linux {version}'.format(version=version) |
| |
| def get_last_doc_update(self, delimiter): |
| try: |
| cmd = ['git', 'log', '-1', '--pretty=format:%cs', '--no-patch', |
| '-L', |
| '/{}/,/\\*\\//:include/uapi/linux/bpf.h'.format(delimiter)] |
| date = subprocess.run(cmd, cwd=linuxRoot, |
| capture_output=True, check=True) |
| return date.stdout.decode().rstrip() |
| except: |
| return '' |
| |
| 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 |
| :Version: {version} |
| {date_field}{date} |
| |
| 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 |
| ======= |
| ''' |
| kernelVersion = self.get_kernel_version() |
| lastUpdate = self.get_last_doc_update(helpersDocStart) |
| |
| PrinterRST.print_license(self) |
| print(header.format(version=kernelVersion, |
| date_field = ':Date: ' if lastUpdate else '', |
| date=lastUpdate)) |
| |
| 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 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(* const %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() |
