1 // Copyright 2023 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_sapphire/internal/host/l2cap/bredr_signaling_channel.h"
16
17 #include "pw_bluetooth_sapphire/internal/host/common/log.h"
18
19 namespace bt::l2cap::internal {
20
BrEdrSignalingChannel(Channel::WeakPtr chan,pw::bluetooth::emboss::ConnectionRole role,pw::async::Dispatcher & dispatcher)21 BrEdrSignalingChannel::BrEdrSignalingChannel(
22 Channel::WeakPtr chan,
23 pw::bluetooth::emboss::ConnectionRole role,
24 pw::async::Dispatcher& dispatcher)
25 : SignalingChannel(std::move(chan), role, dispatcher) {
26 set_mtu(kDefaultMTU);
27
28 // Add default handler for incoming Echo Request commands.
29 ServeRequest(kEchoRequest,
30 [](const ByteBuffer& req_payload, Responder* responder) {
31 responder->Send(req_payload);
32 });
33 }
34
TestLink(const ByteBuffer & data,DataCallback cb)35 bool BrEdrSignalingChannel::TestLink(const ByteBuffer& data, DataCallback cb) {
36 return SendRequest(
37 kEchoRequest,
38 data,
39 [cb = std::move(cb)](Status status, const ByteBuffer& rsp_payload) {
40 if (status == Status::kSuccess) {
41 cb(rsp_payload);
42 } else {
43 cb(BufferView());
44 }
45 return ResponseHandlerAction::kCompleteOutboundTransaction;
46 });
47 }
48
DecodeRxUnit(ByteBufferPtr sdu,const SignalingPacketHandler & cb)49 void BrEdrSignalingChannel::DecodeRxUnit(ByteBufferPtr sdu,
50 const SignalingPacketHandler& cb) {
51 // "Multiple commands may be sent in a single C-frame over Fixed Channel CID
52 // 0x0001 (ACL-U) (v5.0, Vol 3, Part A, Section 4)"
53 BT_DEBUG_ASSERT(sdu);
54 if (sdu->size() < sizeof(CommandHeader)) {
55 bt_log(DEBUG, "l2cap-bredr", "sig: dropped malformed ACL signaling packet");
56 return;
57 }
58
59 size_t sdu_offset = 0;
60 while (sdu_offset + sizeof(CommandHeader) <= sdu->size()) {
61 const auto header_data = sdu->view(sdu_offset, sizeof(CommandHeader));
62 SignalingPacket packet(&header_data);
63
64 uint16_t expected_payload_length = le16toh(packet.header().length);
65 size_t remaining_sdu_length =
66 sdu->size() - sdu_offset - sizeof(CommandHeader);
67 if (remaining_sdu_length < expected_payload_length) {
68 bt_log(DEBUG,
69 "l2cap-bredr",
70 "sig: expected more bytes (%zu < %u); drop",
71 remaining_sdu_length,
72 expected_payload_length);
73 SendCommandReject(
74 packet.header().id, RejectReason::kNotUnderstood, BufferView());
75 return;
76 }
77
78 const auto packet_data =
79 sdu->view(sdu_offset, sizeof(CommandHeader) + expected_payload_length);
80 cb(SignalingPacket(&packet_data, expected_payload_length));
81
82 sdu_offset += packet_data.size();
83 }
84
85 if (sdu_offset != sdu->size()) {
86 bt_log(DEBUG,
87 "l2cap-bredr",
88 "sig: incomplete packet header "
89 "(expected: %zu, left: %zu)",
90 sizeof(CommandHeader),
91 sdu->size() - sdu_offset);
92 }
93 }
94
IsSupportedResponse(CommandCode code) const95 bool BrEdrSignalingChannel::IsSupportedResponse(CommandCode code) const {
96 switch (code) {
97 case kCommandRejectCode:
98 case kConnectionResponse:
99 case kConfigurationResponse:
100 case kDisconnectionResponse:
101 case kEchoResponse:
102 case kInformationResponse:
103 return true;
104 }
105
106 // Other response-type commands are for AMP/LE and are not supported.
107 return false;
108 }
109
110 } // namespace bt::l2cap::internal
111