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 #ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H 20 #define GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H 21 22 #include <grpc/support/port_platform.h> 23 24 #include <grpc/slice.h> 25 #include <grpc/slice_buffer.h> 26 #include "src/core/ext/transport/chttp2/transport/frame.h" 27 #include "src/core/lib/transport/metadata.h" 28 #include "src/core/lib/transport/metadata_batch.h" 29 #include "src/core/lib/transport/transport.h" 30 31 // This should be <= 8. We use 6 to save space. 32 #define GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS 6 33 #define GRPC_CHTTP2_HPACKC_NUM_VALUES (1 << GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS) 34 /* initial table size, per spec */ 35 #define GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE 4096 36 /* maximum table size we'll actually use */ 37 #define GRPC_CHTTP2_HPACKC_MAX_TABLE_SIZE (1024 * 1024) 38 39 extern grpc_core::TraceFlag grpc_http_trace; 40 41 typedef struct { 42 uint32_t filter_elems_sum; 43 uint32_t max_table_size; 44 uint32_t max_table_elems; 45 uint32_t cap_table_elems; 46 /** if non-zero, advertise to the decoder that we'll start using a table 47 of this size */ 48 uint8_t advertise_table_size_change; 49 /** maximum number of bytes we'll use for the decode table (to guard against 50 peers ooming us by setting decode table size high) */ 51 uint32_t max_usable_size; 52 /* one before the lowest usable table index */ 53 uint32_t tail_remote_index; 54 uint32_t table_size; 55 uint32_t table_elems; 56 57 /* filter tables for elems: this tables provides an approximate 58 popularity count for particular hashes, and are used to determine whether 59 a new literal should be added to the compression table or not. 60 They track a single integer that counts how often a particular value has 61 been seen. When that count reaches max (255), all values are halved. */ 62 uint8_t filter_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES]; 63 64 /* entry tables for keys & elems: these tables track values that have been 65 seen and *may* be in the decompressor table */ 66 grpc_slice entries_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES]; 67 grpc_mdelem entries_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES]; 68 uint32_t indices_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES]; 69 uint32_t indices_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES]; 70 71 uint16_t* table_elem_size; 72 } grpc_chttp2_hpack_compressor; 73 74 void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor* c); 75 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor* c); 76 void grpc_chttp2_hpack_compressor_set_max_table_size( 77 grpc_chttp2_hpack_compressor* c, uint32_t max_table_size); 78 void grpc_chttp2_hpack_compressor_set_max_usable_size( 79 grpc_chttp2_hpack_compressor* c, uint32_t max_table_size); 80 81 typedef struct { 82 uint32_t stream_id; 83 bool is_eof; 84 bool use_true_binary_metadata; 85 size_t max_frame_size; 86 grpc_transport_one_way_stats* stats; 87 } grpc_encode_header_options; 88 89 void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor* c, 90 grpc_mdelem** extra_headers, 91 size_t extra_headers_size, 92 grpc_metadata_batch* metadata, 93 const grpc_encode_header_options* options, 94 grpc_slice_buffer* outbuf); 95 96 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H */ 97
