scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions (7a387bed) · Commits · EulixOS / Software / Kernel

scripts/bpf_helpers_doc.py

+154 −1

Original line number	Diff line number	Diff line
		@@ -391,6 +391,154 @@ SEE ALSO

		print('')

		class PrinterHelpers(Printer):
		"""
		A printer for dumping collected information about helpers as C header to
		be included from BPF program.
		@helpers: array of Helper objects to print to standard output
		"""

		type_fwds = [
		'struct bpf_fib_lookup',
		'struct bpf_perf_event_data',
		'struct bpf_perf_event_value',
		'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 pt_regs',
		'struct sk_reuseport_md',
		'struct sockaddr',
		'struct tcphdr',

		'struct __sk_buff',
		'struct sk_msg_md',
		'struct xpd_md',
		]
		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_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 pt_regs',
		'struct sk_reuseport_md',
		'struct sockaddr',
		'struct tcphdr',
		}
		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',
		}

		def print_header(self):
		header = '''\
		/* This is auto-generated file. See bpf_helpers_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("")
		print("Unrecognized type '%s', please add it to known types!" % t)
		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'] == 'bpf_get_socket_cookie' 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
		@@ -405,6 +553,8 @@ Parse eBPF header file and generate documentation for eBPF helper functions.
		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)
		@@ -417,5 +567,8 @@ headerParser = HeaderParser(args.filename)
		headerParser.run()

		# Print formatted output to standard output.
		if args.header:
		printer = PrinterHelpers(headerParser.helpers)
		else:
		printer = PrinterRST(headerParser.helpers)
		printer.print_all()