1 // Copyright 2020 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
15 #include <cstddef>
16 #include <cstdint>
17 #include <cstdio>
18
19 #include "pw_assert/check.h"
20 #include "pw_hdlc/encoded_size.h"
21 #include "pw_hdlc/rpc_channel.h"
22 #include "pw_hdlc/rpc_packets.h"
23 #include "pw_log/log.h"
24 #include "pw_rpc_system_server/rpc_server.h"
25 #include "pw_stream/socket_stream.h"
26
27 namespace pw::rpc::system_server {
28 namespace {
29
30 // Hard-coded to 1055 bytes, which is enough to fit 512-byte payloads when using
31 // HDLC framing.
32 constexpr size_t kMaxTransmissionUnit = 1055;
33 uint16_t socket_port = 33000;
34
35 static_assert(kMaxTransmissionUnit ==
36 hdlc::MaxEncodedFrameSize(rpc::cfg::kEncodingBufferSizeBytes));
37
38 stream::ServerSocket server_socket;
39 stream::SocketStream socket_stream;
40
41 hdlc::FixedMtuChannelOutput<kMaxTransmissionUnit> hdlc_channel_output(
42 socket_stream, hdlc::kDefaultRpcAddress, "HDLC channel");
43 Channel channels[] = {rpc::Channel::Create<1>(&hdlc_channel_output)};
44 rpc::Server server(channels);
45
46 } // namespace
47
set_socket_port(uint16_t new_socket_port)48 void set_socket_port(uint16_t new_socket_port) {
49 socket_port = new_socket_port;
50 }
51
GetServerSocketFd()52 int GetServerSocketFd() { return socket_stream.connection_fd(); }
53
Init()54 void Init() {
55 log_basic::SetOutput([](std::string_view log) {
56 std::fprintf(stderr, "%.*s\n", static_cast<int>(log.size()), log.data());
57 hdlc::WriteUIFrame(1, as_bytes(span<const char>(log)), socket_stream)
58 .IgnoreError(); // TODO(b/242598609): Handle Status properly
59 });
60
61 PW_LOG_INFO("Starting pw_rpc server on port %d", socket_port);
62 PW_CHECK_OK(server_socket.Listen(socket_port));
63 auto accept_result = server_socket.Accept();
64 PW_CHECK_OK(accept_result.status());
65 socket_stream = *std::move(accept_result);
66 }
67
Server()68 rpc::Server& Server() { return server; }
69
Start()70 Status Start() {
71 constexpr size_t kDecoderBufferSize =
72 hdlc::Decoder::RequiredBufferSizeForFrameSize(kMaxTransmissionUnit);
73 // Declare a buffer for decoding incoming HDLC frames.
74 std::array<std::byte, kDecoderBufferSize> input_buffer;
75 hdlc::Decoder decoder(input_buffer);
76
77 while (true) {
78 std::array<std::byte, kMaxTransmissionUnit> data;
79 auto ret_val = socket_stream.Read(data);
80 if (!ret_val.ok()) {
81 if (ret_val.status() == Status::OutOfRange()) {
82 // An out of range status indicates the remote end has disconnected.
83 return OkStatus();
84 }
85 continue;
86 }
87
88 for (std::byte byte : ret_val.value()) {
89 auto result = decoder.Process(byte);
90 if (!result.ok()) {
91 // Non-OK means there isn't a complete packet yet, or there was some
92 // other issue. Wait for more bytes that form a complete packet.
93 continue;
94 }
95 hdlc::Frame& frame = result.value();
96 if (frame.address() != hdlc::kDefaultRpcAddress) {
97 // Wrong address; ignore the packet for now. In the future, this branch
98 // could expand to add packet routing or metrics.
99 continue;
100 }
101
102 server.ProcessPacket(frame.data()).IgnoreError();
103 }
104 }
105 }
106
107 } // namespace pw::rpc::system_server
108