1 /******************************************************************************
2 *
3 * Copyright 2015 Google Inc.
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 #include <mutex>
20
21 #include <base/logging.h>
22 #include <resolv.h>
23 #include <zlib.h>
24
25 #include "btif/include/btif_debug.h"
26 #include "btif/include/btif_debug_btsnoop.h"
27 #include "hci/include/btsnoop_mem.h"
28 #include "internal_include/bt_target.h"
29 #include "osi/include/ringbuffer.h"
30
31 #define REDUCE_HCI_TYPE_TO_SIGNIFICANT_BITS(type) ((type) >> 8)
32
33 // Total btsnoop memory log buffer size
34 #ifndef BTSNOOP_MEM_BUFFER_SIZE
35 static const size_t BTSNOOP_MEM_BUFFER_SIZE = (256 * 1024);
36 #endif
37
38 // Block size for copying buffers (for compression/encoding etc.)
39 static const size_t BLOCK_SIZE = 16384;
40
41 // Maximum line length in bugreport (should be multiple of 4 for base64 output)
42 static const uint8_t MAX_LINE_LENGTH = 128;
43
44 static std::mutex buffer_mutex;
45 static ringbuffer_t* buffer = NULL;
46 static uint64_t last_timestamp_ms = 0;
47
48 static size_t btsnoop_calculate_packet_length(uint16_t type,
49 const uint8_t* data,
50 size_t length);
51
btsnoop_cb(const uint16_t type,const uint8_t * data,const size_t length,const uint64_t timestamp_us)52 static void btsnoop_cb(const uint16_t type, const uint8_t* data,
53 const size_t length, const uint64_t timestamp_us) {
54 btsnooz_header_t header;
55
56 size_t included_length = btsnoop_calculate_packet_length(type, data, length);
57 if (included_length == 0) return;
58
59 std::lock_guard<std::mutex> lock(buffer_mutex);
60
61 // Make room in the ring buffer
62
63 while (ringbuffer_available(buffer) <
64 (included_length + sizeof(btsnooz_header_t))) {
65 ringbuffer_pop(buffer, (uint8_t*)&header, sizeof(btsnooz_header_t));
66 ringbuffer_delete(buffer, header.length - 1);
67 }
68
69 // Insert data
70 header.type = REDUCE_HCI_TYPE_TO_SIGNIFICANT_BITS(type);
71 header.length = included_length + 1; // +1 for type byte
72 header.packet_length = length + 1; // +1 for type byte.
73 header.delta_time_ms =
74 last_timestamp_ms ? timestamp_us - last_timestamp_ms : 0;
75 last_timestamp_ms = timestamp_us;
76
77 ringbuffer_insert(buffer, (uint8_t*)&header, sizeof(btsnooz_header_t));
78 ringbuffer_insert(buffer, data, included_length);
79 }
80
btsnoop_calculate_packet_length(uint16_t type,const uint8_t * data,size_t length)81 static size_t btsnoop_calculate_packet_length(uint16_t type,
82 const uint8_t* data,
83 size_t length) {
84 static const size_t HCI_ACL_HEADER_SIZE = 4;
85 static const size_t L2CAP_HEADER_SIZE = 4;
86 static const size_t L2CAP_CID_OFFSET = (HCI_ACL_HEADER_SIZE + 2);
87 static const uint16_t L2CAP_SIGNALING_CID = 0x0001;
88
89 // Maximum amount of ACL data to log.
90 // Enough for an RFCOMM frame up to the frame check;
91 // not enough for a HID report or audio data.
92 static const size_t MAX_HCI_ACL_LEN = 14;
93
94 // Calculate packet length to be included
95
96 switch (type) {
97 case BT_EVT_TO_LM_HCI_CMD:
98 return length;
99
100 case BT_EVT_TO_BTU_HCI_EVT:
101 return length;
102
103 case BT_EVT_TO_LM_HCI_ACL:
104 case BT_EVT_TO_BTU_HCI_ACL: {
105 size_t len_hci_acl = HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE;
106 // Check if we have enough data for an L2CAP header
107 if (length > len_hci_acl) {
108 uint16_t l2cap_cid =
109 data[L2CAP_CID_OFFSET] | (data[L2CAP_CID_OFFSET + 1] << 8);
110 if (l2cap_cid == L2CAP_SIGNALING_CID) {
111 // For the signaling CID, take the full packet.
112 // That way, the PSM setup is captured, allowing decoding of PSMs down
113 // the road.
114 return length;
115 } else {
116 // Otherwise, return as much as we reasonably can
117 len_hci_acl = MAX_HCI_ACL_LEN;
118 }
119 }
120 return len_hci_acl < length ? len_hci_acl : length;
121 }
122
123 case BT_EVT_TO_LM_HCI_SCO:
124 case BT_EVT_TO_BTU_HCI_SCO:
125 // We're not logging SCO packets at this time since they are not currently
126 // used.
127 FALLTHROUGH_INTENDED; /* FALLTHROUGH */
128 default:
129 return 0;
130 }
131 }
132
btsnoop_compress(ringbuffer_t * rb_dst,ringbuffer_t * rb_src)133 static bool btsnoop_compress(ringbuffer_t* rb_dst, ringbuffer_t* rb_src) {
134 CHECK(rb_dst != NULL);
135 CHECK(rb_src != NULL);
136
137 z_stream zs;
138 zs.zalloc = Z_NULL;
139 zs.zfree = Z_NULL;
140 zs.opaque = Z_NULL;
141
142 if (deflateInit(&zs, Z_DEFAULT_COMPRESSION) != Z_OK) return false;
143
144 bool rc = true;
145 uint8_t block_src[BLOCK_SIZE];
146 uint8_t block_dst[BLOCK_SIZE];
147
148 const size_t num_blocks =
149 (ringbuffer_size(rb_src) + BLOCK_SIZE - 1) / BLOCK_SIZE;
150 for (size_t i = 0; i < num_blocks; ++i) {
151 zs.avail_in =
152 ringbuffer_peek(rb_src, i * BLOCK_SIZE, block_src, BLOCK_SIZE);
153 zs.next_in = block_src;
154
155 do {
156 zs.avail_out = BLOCK_SIZE;
157 zs.next_out = block_dst;
158
159 int err = deflate(&zs, (i == num_blocks - 1) ? Z_FINISH : Z_NO_FLUSH);
160 if (err == Z_STREAM_ERROR) {
161 rc = false;
162 break;
163 }
164
165 const size_t length = BLOCK_SIZE - zs.avail_out;
166 ringbuffer_insert(rb_dst, block_dst, length);
167 } while (zs.avail_out == 0);
168 }
169
170 deflateEnd(&zs);
171 return rc;
172 }
173
btif_debug_btsnoop_init(void)174 void btif_debug_btsnoop_init(void) {
175 if (buffer == NULL) buffer = ringbuffer_init(BTSNOOP_MEM_BUFFER_SIZE);
176 btsnoop_mem_set_callback(btsnoop_cb);
177 }
178
btif_debug_btsnoop_dump(int fd)179 void btif_debug_btsnoop_dump(int fd) {
180 ringbuffer_t* ringbuffer = ringbuffer_init(BTSNOOP_MEM_BUFFER_SIZE);
181 if (ringbuffer == NULL) {
182 dprintf(fd, "%s Unable to allocate memory for compression", __func__);
183 return;
184 }
185
186 // Prepend preamble
187
188 btsnooz_preamble_t preamble;
189 preamble.version = BTSNOOZ_CURRENT_VERSION;
190 preamble.last_timestamp_ms = last_timestamp_ms;
191 ringbuffer_insert(ringbuffer, (uint8_t*)&preamble,
192 sizeof(btsnooz_preamble_t));
193
194 // Compress data
195
196 uint8_t b64_in[3] = {0};
197 char b64_out[5] = {0};
198
199 size_t line_length = 0;
200
201 bool rc;
202 {
203 std::lock_guard<std::mutex> lock(buffer_mutex);
204 dprintf(fd, "--- BEGIN:BTSNOOP_LOG_SUMMARY (%zu bytes in) ---\n",
205 ringbuffer_size(buffer));
206 rc = btsnoop_compress(ringbuffer, buffer);
207 }
208
209 if (!rc) {
210 dprintf(fd, "%s Log compression failed", __func__);
211 goto error;
212 }
213
214 // Base64 encode & output
215
216 while (ringbuffer_size(ringbuffer) > 0) {
217 size_t read = ringbuffer_pop(ringbuffer, b64_in, 3);
218 if (line_length >= MAX_LINE_LENGTH) {
219 dprintf(fd, "\n");
220 line_length = 0;
221 }
222 line_length += b64_ntop(b64_in, read, b64_out, 5);
223 dprintf(fd, "%s", b64_out);
224 }
225
226 dprintf(fd, "\n--- END:BTSNOOP_LOG_SUMMARY ---\n");
227
228 error:
229 ringbuffer_free(ringbuffer);
230 }
231