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1#!/usr/bin/env python2.7
2
3# Copyright 2017 gRPC authors.
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#     http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17import collections
18import perfection
19import sys
20
21_MAX_HEADER_LIST_SIZE = 16 * 1024 * 1024
22
23Setting = collections.namedtuple('Setting', 'id default min max on_error')
24OnError = collections.namedtuple('OnError', 'behavior code')
25clamp_invalid_value = OnError('CLAMP_INVALID_VALUE', 'PROTOCOL_ERROR')
26disconnect_on_invalid_value = lambda e: OnError('DISCONNECT_ON_INVALID_VALUE', e
27                                               )
28DecoratedSetting = collections.namedtuple('DecoratedSetting',
29                                          'enum name setting')
30
31_SETTINGS = {
32    'HEADER_TABLE_SIZE':
33        Setting(1, 4096, 0, 0xffffffff, clamp_invalid_value),
34    'ENABLE_PUSH':
35        Setting(2, 1, 0, 1, disconnect_on_invalid_value('PROTOCOL_ERROR')),
36    'MAX_CONCURRENT_STREAMS':
37        Setting(3, 0xffffffff, 0, 0xffffffff,
38                disconnect_on_invalid_value('PROTOCOL_ERROR')),
39    'INITIAL_WINDOW_SIZE':
40        Setting(4, 65535, 0, 0x7fffffff,
41                disconnect_on_invalid_value('FLOW_CONTROL_ERROR')),
42    'MAX_FRAME_SIZE':
43        Setting(5, 16384, 16384, 16777215,
44                disconnect_on_invalid_value('PROTOCOL_ERROR')),
45    'MAX_HEADER_LIST_SIZE':
46        Setting(6, _MAX_HEADER_LIST_SIZE, 0, _MAX_HEADER_LIST_SIZE,
47                clamp_invalid_value),
48    'GRPC_ALLOW_TRUE_BINARY_METADATA':
49        Setting(0xfe03, 0, 0, 1, clamp_invalid_value),
50}
51
52H = open('src/core/ext/transport/chttp2/transport/http2_settings.h', 'w')
53C = open('src/core/ext/transport/chttp2/transport/http2_settings.c', 'w')
54
55
56# utility: print a big comment block into a set of files
57def put_banner(files, banner):
58    for f in files:
59        print >> f, '/*'
60        for line in banner:
61            print >> f, ' * %s' % line
62        print >> f, ' */'
63        print >> f
64
65
66# copy-paste copyright notice from this file
67with open(sys.argv[0]) as my_source:
68    copyright = []
69    for line in my_source:
70        if line[0] != '#': break
71    for line in my_source:
72        if line[0] == '#':
73            copyright.append(line)
74            break
75    for line in my_source:
76        if line[0] != '#':
77            break
78        copyright.append(line)
79    put_banner([H, C], [line[2:].rstrip() for line in copyright])
80
81put_banner(
82    [H, C],
83    ["Automatically generated by tools/codegen/core/gen_settings_ids.py"])
84
85print >> H, "#ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H"
86print >> H, "#define GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H"
87print >> H
88print >> H, "#include <stdint.h>"
89print >> H, "#include <stdbool.h>"
90print >> H
91
92print >> C, "#include \"src/core/ext/transport/chttp2/transport/http2_settings.h\""
93print >> C
94print >> C, "#include <grpc/support/useful.h>"
95print >> C, "#include \"src/core/lib/transport/http2_errors.h\""
96print >> C
97
98p = perfection.hash_parameters(sorted(x.id for x in _SETTINGS.values()))
99print p
100
101
102def hash(i):
103    i += p.offset
104    x = i % p.t
105    y = i / p.t
106    return x + p.r[y]
107
108
109decorated_settings = [
110    DecoratedSetting(hash(setting.id), name, setting)
111    for name, setting in _SETTINGS.iteritems()
112]
113
114print >> H, 'typedef enum {'
115for decorated_setting in sorted(decorated_settings):
116    print >> H, '  GRPC_CHTTP2_SETTINGS_%s = %d, /* wire id %d */' % (
117        decorated_setting.name, decorated_setting.enum,
118        decorated_setting.setting.id)
119print >> H, '} grpc_chttp2_setting_id;'
120print >> H
121print >> H, '#define GRPC_CHTTP2_NUM_SETTINGS %d' % (
122    max(x.enum for x in decorated_settings) + 1)
123
124print >> H, 'extern const uint16_t grpc_setting_id_to_wire_id[];'
125print >> C, 'const uint16_t grpc_setting_id_to_wire_id[] = {%s};' % ','.join(
126    '%d' % s for s in p.slots)
127print >> H
128print >> H, "bool grpc_wire_id_to_setting_id(uint32_t wire_id, grpc_chttp2_setting_id *out);"
129cgargs = {
130    'r': ','.join('%d' % (r if r is not None else 0) for r in p.r),
131    't': p.t,
132    'offset': abs(p.offset),
133    'offset_sign': '+' if p.offset > 0 else '-'
134}
135print >> C, """
136bool grpc_wire_id_to_setting_id(uint32_t wire_id, grpc_chttp2_setting_id *out) {
137  uint32_t i = wire_id %(offset_sign)s %(offset)d;
138  uint32_t x = i %% %(t)d;
139  uint32_t y = i / %(t)d;
140  uint32_t h = x;
141  switch (y) {
142""" % cgargs
143for i, r in enumerate(p.r):
144    if not r: continue
145    if r < 0: print >> C, 'case %d: h -= %d; break;' % (i, -r)
146    else: print >> C, 'case %d: h += %d; break;' % (i, r)
147print >> C, """
148  }
149  *out = (grpc_chttp2_setting_id)h;
150  return h < GPR_ARRAY_SIZE(grpc_setting_id_to_wire_id) && grpc_setting_id_to_wire_id[h] == wire_id;
151}
152""" % cgargs
153
154print >> H, """
155typedef enum {
156  GRPC_CHTTP2_CLAMP_INVALID_VALUE,
157  GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE
158} grpc_chttp2_invalid_value_behavior;
159
160typedef struct {
161  const char *name;
162  uint32_t default_value;
163  uint32_t min_value;
164  uint32_t max_value;
165  grpc_chttp2_invalid_value_behavior invalid_value_behavior;
166  uint32_t error_value;
167} grpc_chttp2_setting_parameters;
168
169extern const grpc_chttp2_setting_parameters grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS];
170"""
171print >> C, "const grpc_chttp2_setting_parameters grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS] = {"
172i = 0
173for decorated_setting in sorted(decorated_settings):
174    while i < decorated_setting.enum:
175        print >> C, "{NULL, 0, 0, 0, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},"
176        i += 1
177    print >> C, "{\"%s\", %du, %du, %du, GRPC_CHTTP2_%s, GRPC_HTTP2_%s}," % (
178        decorated_setting.name,
179        decorated_setting.setting.default,
180        decorated_setting.setting.min,
181        decorated_setting.setting.max,
182        decorated_setting.setting.on_error.behavior,
183        decorated_setting.setting.on_error.code,
184    )
185    i += 1
186print >> C, "};"
187
188print >> H
189print >> H, "#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HTTP2_SETTINGS_H */"
190
191H.close()
192C.close()
193