1 // Copyright 2024 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 "pw_bluetooth_proxy/basic_l2cap_channel.h"
16
17 #include "pw_bluetooth/emboss_util.h"
18 #include "pw_bluetooth/hci_data.emb.h"
19 #include "pw_bluetooth/l2cap_frames.emb.h"
20 #include "pw_log/log.h"
21 #include "pw_status/try.h"
22
23 namespace pw::bluetooth::proxy {
24
Create(L2capChannelManager & l2cap_channel_manager,uint16_t connection_handle,uint16_t local_cid,uint16_t remote_cid,pw::Function<void (pw::span<uint8_t> payload)> && payload_from_controller_fn)25 pw::Result<BasicL2capChannel> BasicL2capChannel::Create(
26 L2capChannelManager& l2cap_channel_manager,
27 uint16_t connection_handle,
28 uint16_t local_cid,
29 uint16_t remote_cid,
30 pw::Function<void(pw::span<uint8_t> payload)>&&
31 payload_from_controller_fn) {
32 if (!L2capReadChannel::AreValidParameters(connection_handle, local_cid) ||
33 !L2capWriteChannel::AreValidParameters(connection_handle, remote_cid)) {
34 return pw::Status::InvalidArgument();
35 }
36
37 return BasicL2capChannel(
38 /*l2cap_channel_manager=*/l2cap_channel_manager,
39 /*connection_handle=*/connection_handle,
40 /*local_cid=*/local_cid,
41 /*remote_cid=*/remote_cid,
42 /*payload_from_controller_fn=*/std::move(payload_from_controller_fn));
43 }
44
Write(pw::span<const uint8_t> payload)45 pw::Status BasicL2capChannel::Write(pw::span<const uint8_t> payload) {
46 // TODO: https://pwbug.dev/360929142 - Reject payloads exceeding MTU.
47
48 pw::Result<H4PacketWithH4> h4_result = PopulateTxL2capPacket(payload.size());
49 if (!h4_result.ok()) {
50 // This can fail as a result of the L2CAP PDU not fitting in an H4 buffer
51 // or if all buffers are occupied.
52 // TODO: https://pwbug.dev/365179076 - Once we support ACL fragmentation,
53 // this function will not fail due to the L2CAP PDU size not fitting.
54 return h4_result.status();
55 }
56 H4PacketWithH4 h4_packet = std::move(*h4_result);
57
58 PW_TRY_ASSIGN(
59 auto acl,
60 MakeEmbossWriter<emboss::AclDataFrameWriter>(h4_packet.GetHciSpan()));
61 PW_TRY_ASSIGN(auto bframe,
62 MakeEmbossWriter<emboss::BFrameWriter>(
63 acl.payload().BackingStorage().data(),
64 acl.payload().BackingStorage().SizeInBytes()));
65 std::memcpy(
66 bframe.payload().BackingStorage().data(), payload.data(), payload.size());
67
68 return QueuePacket(std::move(h4_packet));
69 }
70
BasicL2capChannel(L2capChannelManager & l2cap_channel_manager,uint16_t connection_handle,uint16_t local_cid,uint16_t remote_cid,pw::Function<void (pw::span<uint8_t> payload)> && payload_from_controller_fn)71 BasicL2capChannel::BasicL2capChannel(
72 L2capChannelManager& l2cap_channel_manager,
73 uint16_t connection_handle,
74 uint16_t local_cid,
75 uint16_t remote_cid,
76 pw::Function<void(pw::span<uint8_t> payload)>&& payload_from_controller_fn)
77 : L2capReadChannel(l2cap_channel_manager,
78 std::move(payload_from_controller_fn),
79 connection_handle,
80 local_cid),
81 L2capWriteChannel(l2cap_channel_manager,
82 connection_handle,
83 AclTransportType::kLe,
84 remote_cid) {}
85
HandlePduFromController(pw::span<uint8_t> bframe)86 bool BasicL2capChannel::HandlePduFromController(pw::span<uint8_t> bframe) {
87 Result<emboss::BFrameWriter> bframe_view =
88 MakeEmbossWriter<emboss::BFrameWriter>(bframe);
89
90 if (!bframe_view.ok()) {
91 // TODO: https://pwbug.dev/360929142 - Stop channel on error.
92 PW_LOG_ERROR("(CID: 0x%X) Received invalid B-frame. So will drop.",
93 local_cid());
94 } else {
95 SendPayloadFromControllerToClient(
96 span(bframe_view->payload().BackingStorage().data(),
97 bframe_view->payload().SizeInBytes()));
98 }
99 return true;
100 }
101
HandlePduFromHost(pw::span<uint8_t>)102 bool BasicL2capChannel::HandlePduFromHost(pw::span<uint8_t>) {
103 // Always forward to controller.
104 return false;
105 }
106
107 } // namespace pw::bluetooth::proxy
108