btif_debug_btsnoop.c revision ae3ba35cfd03f21225bbf58dd3d5f0034b13fe09 
1/******************************************************************************
2 *
3 *  Copyright (C) 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 <assert.h>
20#include <resolv.h>
21#include <zlib.h>
22
23#include "btif/include/btif_debug.h"
24#include "btif/include/btif_debug_btsnoop.h"
25#include "hci/include/btsnoop_mem.h"
26#include "include/bt_target.h"
27#include "osi/include/ringbuffer.h"
28
29#define REDUCE_HCI_TYPE_TO_SIGNIFICANT_BITS(type) (type >> 8)
30
31// Total btsnoop memory log buffer size
32#ifndef BTSNOOP_MEM_BUFFER_SIZE
33static const size_t BTSNOOP_MEM_BUFFER_SIZE = (256 * 1024);
34#endif
35
36// Block size for copying buffers (for compression/encoding etc.)
37static const size_t BLOCK_SIZE = 16384;
38
39// Maximum line length in bugreport (should be multiple of 4 for base64 output)
40static const uint8_t MAX_LINE_LENGTH = 128;
41
42static ringbuffer_t *buffer = NULL;
43static uint64_t last_timestamp_ms = 0;
44
45static size_t btsnoop_calculate_packet_length(uint16_t type, const uint8_t *data, size_t length);
46
47static void btsnoop_cb(const uint16_t type, const uint8_t *data, const size_t length) {
48  btsnooz_header_t header;
49
50  size_t included_length = btsnoop_calculate_packet_length(type, data, length);
51  if (included_length == 0)
52    return;
53
54  // Make room in the ring buffer
55
56  while (ringbuffer_available(buffer) < (included_length + sizeof(btsnooz_header_t))) {
57    ringbuffer_pop(buffer, (uint8_t *)&header, sizeof(btsnooz_header_t));
58    ringbuffer_delete(buffer, header.length - 1);
59  }
60
61  // Insert data
62
63  const uint64_t now = btif_debug_ts();
64
65  header.type = REDUCE_HCI_TYPE_TO_SIGNIFICANT_BITS(type);
66  header.length = included_length + 1;  // +1 for type byte
67  header.packet_length = length + 1;  // +1 for type byte.
68  header.delta_time_ms = last_timestamp_ms ? now - last_timestamp_ms : 0;
69  last_timestamp_ms = now;
70
71  ringbuffer_insert(buffer, (uint8_t *)&header, sizeof(btsnooz_header_t));
72  ringbuffer_insert(buffer, data, included_length);
73}
74
75static size_t btsnoop_calculate_packet_length(uint16_t type, const uint8_t *data, size_t length) {
76  static const size_t HCI_ACL_HEADER_SIZE = 4;
77  static const size_t L2CAP_HEADER_SIZE = 4;
78  static const size_t L2CAP_CID_OFFSET = (HCI_ACL_HEADER_SIZE + 2);
79  static const uint16_t L2CAP_SIGNALING_CID = 0x0001;
80
81  // Maximum amount of ACL data to log.
82  // Enough for an RFCOMM frame up to the frame check;
83  // not enough for a HID report or audio data.
84  static const size_t MAX_HCI_ACL_LEN = 14;
85
86  // Calculate packet length to be included
87
88  switch (type) {
89    case BT_EVT_TO_LM_HCI_CMD:
90      return length;
91
92    case BT_EVT_TO_BTU_HCI_EVT:
93      return length;
94
95    case BT_EVT_TO_LM_HCI_ACL:
96    case BT_EVT_TO_BTU_HCI_ACL:
97    {
98      size_t len_hci_acl = HCI_ACL_HEADER_SIZE + L2CAP_HEADER_SIZE;
99      // Check if we have enough data for an L2CAP header
100      if (length > len_hci_acl) {
101        uint16_t l2cap_cid = data[L2CAP_CID_OFFSET] | (data[L2CAP_CID_OFFSET + 1] << 8);
102        if (l2cap_cid == L2CAP_SIGNALING_CID) {
103          // For the signaling CID, take the full packet.
104          // That way, the PSM setup is captured, allowing decoding of PSMs down the road.
105          return length;
106        } else {
107          // Otherwise, return as much as we reasonably can
108          len_hci_acl = MAX_HCI_ACL_LEN;
109        }
110      }
111      return len_hci_acl < length ? len_hci_acl : length;
112    }
113
114    case BT_EVT_TO_LM_HCI_SCO:
115    case BT_EVT_TO_BTU_HCI_SCO:
116      // We're not logging SCO packets at this time since they are not currently used.
117      // FALLTHROUGH
118    default:
119      return 0;
120  }
121}
122
123static bool btsnoop_compress(ringbuffer_t *rb_dst, ringbuffer_t *rb_src) {
124  assert(rb_dst != NULL);
125  assert(rb_src != NULL);
126
127  z_stream zs = {.zalloc = Z_NULL, .zfree = Z_NULL, .opaque = Z_NULL};
128  if (deflateInit(&zs, Z_DEFAULT_COMPRESSION) != Z_OK)
129    return false;
130
131  bool rc = true;
132  uint8_t block_src[BLOCK_SIZE];
133  uint8_t block_dst[BLOCK_SIZE];
134
135  const size_t num_blocks = (ringbuffer_size(rb_src) + BLOCK_SIZE - 1) / BLOCK_SIZE;
136  for (size_t i = 0; i < num_blocks; ++i) {
137    zs.avail_in = ringbuffer_peek(rb_src, i * BLOCK_SIZE, block_src, BLOCK_SIZE);
138    zs.next_in = block_src;
139
140    do {
141      zs.avail_out = BLOCK_SIZE;
142      zs.next_out = block_dst;
143
144      int err = deflate(&zs, (i == num_blocks - 1) ? Z_FINISH : Z_NO_FLUSH);
145      if (err == Z_STREAM_ERROR) {
146        rc = false;
147        break;
148      }
149
150      const size_t length = BLOCK_SIZE - zs.avail_out;
151      ringbuffer_insert(rb_dst, block_dst, length);
152    } while (zs.avail_out == 0);
153  }
154
155  deflateEnd(&zs);
156  return rc;
157}
158
159void btif_debug_btsnoop_init(void) {
160  if (buffer == NULL)
161    buffer = ringbuffer_init(BTSNOOP_MEM_BUFFER_SIZE);
162  btsnoop_mem_set_callback(btsnoop_cb);
163}
164
165void btif_debug_btsnoop_dump(int fd) {
166  dprintf(fd, "--- BEGIN:BTSNOOP_LOG_SUMMARY (%zu bytes in) ---\n", ringbuffer_size(buffer));
167
168  ringbuffer_t *ringbuffer = ringbuffer_init(BTSNOOP_MEM_BUFFER_SIZE);
169  if (ringbuffer == NULL) {
170    dprintf(fd, "%s Unable to allocate memory for compression", __func__);
171    return;
172  }
173
174  // Prepend preamble
175
176  btsnooz_preamble_t preamble;
177  preamble.version = BTSNOOZ_CURRENT_VERSION;
178  preamble.last_timestamp_ms = last_timestamp_ms;
179  ringbuffer_insert(ringbuffer, (uint8_t *)&preamble, sizeof(btsnooz_preamble_t));
180
181  // Compress data
182
183  bool rc = btsnoop_compress(ringbuffer, buffer);
184  if (rc == false) {
185    dprintf(fd, "%s Log compression failed", __func__);
186    goto error;
187  }
188
189  // Base64 encode & output
190
191  uint8_t b64_in[3] = {0};
192  char b64_out[5] = {0};
193
194  size_t line_length = 0;
195  while (ringbuffer_size(ringbuffer) > 0) {
196    size_t read = ringbuffer_pop(ringbuffer, b64_in, 3);
197    if (line_length >= MAX_LINE_LENGTH) {
198      dprintf(fd, "\n");
199      line_length = 0;
200    }
201    line_length += b64_ntop(b64_in, read, b64_out, 5);
202    dprintf(fd, "%s", b64_out);
203  }
204
205  dprintf(fd, "\n--- END:BTSNOOP_LOG_SUMMARY ---\n");
206
207error:
208  ringbuffer_free(ringbuffer);
209}
210