1 // Copyright 2022 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <cstddef> 17 #include <cstdint> 18 #include <limits> 19 20 #include "pw_bytes/span.h" 21 #include "pw_transfer/handler.h" 22 #include "pw_transfer/internal/config.h" 23 #include "pw_transfer/internal/server_context.h" 24 #include "pw_transfer/transfer.raw_rpc.pb.h" 25 #include "pw_transfer/transfer_thread.h" 26 27 namespace pw::transfer { 28 namespace internal { 29 30 class Chunk; 31 32 } // namespace internal 33 34 class TransferService : public pw_rpc::raw::Transfer::Service<TransferService> { 35 public: 36 // Initializes a TransferService that can be registered with an RPC server. 37 // 38 // The transfer service requires a work queue to perform deferred tasks, such 39 // as handling transfer timeouts and retries. This work queue does not need to 40 // be unique to the transfer service; it may be shared with other parts of the 41 // system. 42 // 43 // The provided buffer is used to stage data from transfer chunks before it is 44 // written out to the writer. The size of this buffer is the largest amount of 45 // data that can be sent in a single transfer chunk, excluding any transport 46 // layer overhead. 47 // 48 // max_pending_bytes is the maximum amount of data to ask for at a 49 // time during a write transfer, unless told a more restrictive amount by a 50 // transfer handler. This size can span multiple chunks. A larger value 51 // generally increases the efficiency of write transfers when sent over a 52 // reliable transport. However, if the underlying transport is unreliable, 53 // larger values could slow down a transfer in the event of repeated packet 54 // loss. 55 TransferService( 56 TransferThread& transfer_thread, 57 uint32_t max_pending_bytes, 58 chrono::SystemClock::duration chunk_timeout = cfg::kDefaultChunkTimeout, 59 uint8_t max_retries = cfg::kDefaultMaxRetries, 60 uint32_t extend_window_divisor = cfg::kDefaultExtendWindowDivisor, 61 uint32_t max_lifetime_retries = cfg::kDefaultMaxLifetimeRetries) 62 : max_parameters_(max_pending_bytes, 63 transfer_thread.max_chunk_size(), 64 extend_window_divisor), 65 thread_(transfer_thread), 66 chunk_timeout_(chunk_timeout), 67 max_retries_(max_retries), 68 max_lifetime_retries_(max_lifetime_retries), 69 next_session_id_(1) {} 70 71 TransferService(const TransferService&) = delete; 72 TransferService(TransferService&&) = delete; 73 74 TransferService& operator=(const TransferService&) = delete; 75 TransferService& operator=(TransferService&&) = delete; 76 Read(RawServerReaderWriter & reader_writer)77 void Read(RawServerReaderWriter& reader_writer) { 78 reader_writer.set_on_next([this](ConstByteSpan message) { 79 HandleChunk(message, internal::TransferType::kTransmit); 80 }); 81 thread_.SetServerReadStream(reader_writer); 82 } 83 Write(RawServerReaderWriter & reader_writer)84 void Write(RawServerReaderWriter& reader_writer) { 85 reader_writer.set_on_next([this](ConstByteSpan message) { 86 HandleChunk(message, internal::TransferType::kReceive); 87 }); 88 thread_.SetServerWriteStream(reader_writer); 89 } 90 RegisterHandler(Handler & handler)91 void RegisterHandler(Handler& handler) { 92 thread_.AddTransferHandler(handler); 93 } 94 UnregisterHandler(Handler & handler)95 void UnregisterHandler(Handler& handler) { 96 thread_.RemoveTransferHandler(handler); 97 } 98 set_max_pending_bytes(uint32_t max_pending_bytes)99 void set_max_pending_bytes(uint32_t max_pending_bytes) { 100 max_parameters_.set_pending_bytes(max_pending_bytes); 101 } 102 103 // Sets the maximum size for the data in a pw_transfer chunk. Note that the 104 // max chunk size must always fit within the transfer thread's chunk buffer. set_max_chunk_size_bytes(uint32_t max_chunk_size_bytes)105 void set_max_chunk_size_bytes(uint32_t max_chunk_size_bytes) { 106 max_parameters_.set_max_chunk_size_bytes(max_chunk_size_bytes); 107 } 108 set_chunk_timeout(chrono::SystemClock::duration chunk_timeout)109 void set_chunk_timeout(chrono::SystemClock::duration chunk_timeout) { 110 chunk_timeout_ = chunk_timeout; 111 } 112 set_max_retries(uint8_t max_retries)113 void set_max_retries(uint8_t max_retries) { max_retries_ = max_retries; } 114 set_extend_window_divisor(uint32_t extend_window_divisor)115 Status set_extend_window_divisor(uint32_t extend_window_divisor) { 116 if (extend_window_divisor <= 1) { 117 return Status::InvalidArgument(); 118 } 119 120 max_parameters_.set_extend_window_divisor(extend_window_divisor); 121 return OkStatus(); 122 } 123 124 private: 125 void HandleChunk(ConstByteSpan message, internal::TransferType type); 126 127 // TODO(frolv): This could be more sophisticated and less predictable. GenerateNewSessionId()128 uint32_t GenerateNewSessionId() { return next_session_id_++; } 129 130 internal::TransferParameters max_parameters_; 131 TransferThread& thread_; 132 133 chrono::SystemClock::duration chunk_timeout_; 134 uint8_t max_retries_; 135 uint32_t max_lifetime_retries_; 136 137 uint32_t next_session_id_; 138 }; 139 140 } // namespace pw::transfer 141