scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions

        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

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)

headerParser.run()

# Print formatted output to standard output.

if args.header:

    printer = PrinterHelpers(headerParser.helpers)

else:

    printer = PrinterRST(headerParser.helpers)

printer.print_all()