1 /*
2 *
3 * Copyright 2015 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 *
17 */
18
19 #include <grpc/support/port_platform.h>
20
21 #include "src/core/ext/transport/chttp2/transport/frame_window_update.h"
22 #include "src/core/ext/transport/chttp2/transport/internal.h"
23
24 #include <grpc/support/alloc.h>
25 #include <grpc/support/log.h>
26 #include <grpc/support/string_util.h>
27
grpc_chttp2_window_update_create(uint32_t id,uint32_t window_update,grpc_transport_one_way_stats * stats)28 grpc_slice grpc_chttp2_window_update_create(
29 uint32_t id, uint32_t window_update, grpc_transport_one_way_stats* stats) {
30 static const size_t frame_size = 13;
31 grpc_slice slice = GRPC_SLICE_MALLOC(frame_size);
32 stats->header_bytes += frame_size;
33 uint8_t* p = GRPC_SLICE_START_PTR(slice);
34
35 GPR_ASSERT(window_update);
36
37 *p++ = 0;
38 *p++ = 0;
39 *p++ = 4;
40 *p++ = GRPC_CHTTP2_FRAME_WINDOW_UPDATE;
41 *p++ = 0;
42 *p++ = static_cast<uint8_t>(id >> 24);
43 *p++ = static_cast<uint8_t>(id >> 16);
44 *p++ = static_cast<uint8_t>(id >> 8);
45 *p++ = static_cast<uint8_t>(id);
46 *p++ = static_cast<uint8_t>(window_update >> 24);
47 *p++ = static_cast<uint8_t>(window_update >> 16);
48 *p++ = static_cast<uint8_t>(window_update >> 8);
49 *p++ = static_cast<uint8_t>(window_update);
50
51 return slice;
52 }
53
grpc_chttp2_window_update_parser_begin_frame(grpc_chttp2_window_update_parser * parser,uint32_t length,uint8_t flags)54 grpc_error* grpc_chttp2_window_update_parser_begin_frame(
55 grpc_chttp2_window_update_parser* parser, uint32_t length, uint8_t flags) {
56 if (flags || length != 4) {
57 char* msg;
58 gpr_asprintf(&msg, "invalid window update: length=%d, flags=%02x", length,
59 flags);
60 grpc_error* err = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
61 gpr_free(msg);
62 return err;
63 }
64 parser->byte = 0;
65 parser->amount = 0;
66 return GRPC_ERROR_NONE;
67 }
68
grpc_chttp2_window_update_parser_parse(void * parser,grpc_chttp2_transport * t,grpc_chttp2_stream * s,grpc_slice slice,int is_last)69 grpc_error* grpc_chttp2_window_update_parser_parse(void* parser,
70 grpc_chttp2_transport* t,
71 grpc_chttp2_stream* s,
72 grpc_slice slice,
73 int is_last) {
74 uint8_t* const beg = GRPC_SLICE_START_PTR(slice);
75 uint8_t* const end = GRPC_SLICE_END_PTR(slice);
76 uint8_t* cur = beg;
77 grpc_chttp2_window_update_parser* p =
78 static_cast<grpc_chttp2_window_update_parser*>(parser);
79
80 while (p->byte != 4 && cur != end) {
81 p->amount |= (static_cast<uint32_t>(*cur)) << (8 * (3 - p->byte));
82 cur++;
83 p->byte++;
84 }
85
86 if (s != nullptr) {
87 s->stats.incoming.framing_bytes += static_cast<uint32_t>(end - cur);
88 }
89
90 if (p->byte == 4) {
91 uint32_t received_update = p->amount;
92 if (received_update == 0 || (received_update & 0x80000000u)) {
93 char* msg;
94 gpr_asprintf(&msg, "invalid window update bytes: %d", p->amount);
95 grpc_error* err = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
96 gpr_free(msg);
97 return err;
98 }
99 GPR_ASSERT(is_last);
100
101 if (t->incoming_stream_id != 0) {
102 if (s != nullptr) {
103 s->flow_control->RecvUpdate(received_update);
104 if (grpc_chttp2_list_remove_stalled_by_stream(t, s)) {
105 grpc_chttp2_mark_stream_writable(t, s);
106 grpc_chttp2_initiate_write(
107 t, GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE);
108 }
109 }
110 } else {
111 bool was_zero = t->flow_control->remote_window() <= 0;
112 t->flow_control->RecvUpdate(received_update);
113 bool is_zero = t->flow_control->remote_window() <= 0;
114 if (was_zero && !is_zero) {
115 grpc_chttp2_initiate_write(
116 t, GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED);
117 }
118 }
119 }
120
121 return GRPC_ERROR_NONE;
122 }
123