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1 /* | 1 /* |
2 * libjingle | 2 * libjingle |
3 * Copyright 2011 Google Inc. | 3 * Copyright 2011 Google Inc. |
4 * | 4 * |
5 * Redistribution and use in source and binary forms, with or without | 5 * Redistribution and use in source and binary forms, with or without |
6 * modification, are permitted provided that the following conditions are met: | 6 * modification, are permitted provided that the following conditions are met: |
7 * | 7 * |
8 * 1. Redistributions of source code must retain the above copyright notice, | 8 * 1. Redistributions of source code must retain the above copyright notice, |
9 * this list of conditions and the following disclaimer. | 9 * this list of conditions and the following disclaimer. |
10 * 2. Redistributions in binary form must reproduce the above copyright notice, | 10 * 2. Redistributions in binary form must reproduce the above copyright notice, |
11 * this list of conditions and the following disclaimer in the documentation | 11 * this list of conditions and the following disclaimer in the documentation |
12 * and/or other materials provided with the distribution. | 12 * and/or other materials provided with the distribution. |
13 * 3. The name of the author may not be used to endorse or promote products | 13 * 3. The name of the author may not be used to endorse or promote products |
14 * derived from this software without specific prior written permission. | 14 * derived from this software without specific prior written permission. |
15 * | 15 * |
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED | 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO | 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; | 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR | 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF | 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 */ | 26 */ |
27 | 27 |
28 #include "talk/media/base/rtputils.h" | 28 #include "talk/media/base/rtputils.h" |
29 | 29 |
30 #include "talk/media/base/turnutils.h" | |
31 #include "webrtc/base/asyncpacketsocket.h" | |
pthatcher1
2016/01/14 19:34:02
Dependency on a socket is weird for an rtputils cl
Sergey Ulanov
2016/01/14 20:13:10
Done.
| |
32 #include "webrtc/base/checks.h" | |
33 #include "webrtc/base/messagedigest.h" | |
34 | |
30 namespace cricket { | 35 namespace cricket { |
31 | 36 |
32 static const uint8_t kRtpVersion = 2; | 37 static const uint8_t kRtpVersion = 2; |
33 static const size_t kRtpFlagsOffset = 0; | 38 static const size_t kRtpFlagsOffset = 0; |
34 static const size_t kRtpPayloadTypeOffset = 1; | 39 static const size_t kRtpPayloadTypeOffset = 1; |
35 static const size_t kRtpSeqNumOffset = 2; | 40 static const size_t kRtpSeqNumOffset = 2; |
36 static const size_t kRtpTimestampOffset = 4; | 41 static const size_t kRtpTimestampOffset = 4; |
37 static const size_t kRtpSsrcOffset = 8; | 42 static const size_t kRtpSsrcOffset = 8; |
38 static const size_t kRtcpPayloadTypeOffset = 1; | 43 static const size_t kRtcpPayloadTypeOffset = 1; |
44 static const size_t kRtpExtensionHeaderLen = 4; | |
45 static const size_t kAbsSendTimeExtensionLen = 3; | |
46 static const size_t kOneByteExtensionHeaderLen = 1; | |
47 | |
48 namespace { | |
49 | |
50 // Fake auth tag written by the sender when external authentication is enabled. | |
51 // HMAC in packet will be compared against this value before updating packet | |
52 // with actual HMAC value. | |
53 static const uint8_t kFakeAuthTag[10] = { | |
54 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd | |
55 }; | |
56 | |
57 void UpdateAbsSendTimeExtensionValue(uint8_t* extension_data, | |
58 size_t length, | |
59 uint64_t time_us) { | |
60 // Absolute send time in RTP streams. | |
61 // | |
62 // The absolute send time is signaled to the receiver in-band using the | |
63 // general mechanism for RTP header extensions [RFC5285]. The payload | |
64 // of this extension (the transmitted value) is a 24-bit unsigned integer | |
65 // containing the sender's current time in seconds as a fixed point number | |
66 // with 18 bits fractional part. | |
67 // | |
68 // The form of the absolute send time extension block: | |
69 // | |
70 // 0 1 2 3 | |
71 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
72 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
73 // | ID | len=2 | absolute send time | | |
74 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
75 if (length != kAbsSendTimeExtensionLen) { | |
76 RTC_NOTREACHED(); | |
77 return; | |
78 } | |
79 | |
80 // Convert microseconds to a 6.18 fixed point value in seconds. | |
81 uint32_t send_time = ((time_us << 18) / 1000000) & 0x00FFFFFF; | |
82 extension_data[0] = static_cast<uint8_t>(send_time >> 16); | |
83 extension_data[1] = static_cast<uint8_t>(send_time >> 8); | |
84 extension_data[2] = static_cast<uint8_t>(send_time); | |
85 } | |
86 | |
87 // Assumes |length| is actual packet length + tag length. Updates HMAC at end of | |
88 // the RTP packet. | |
89 void UpdateRtpAuthTag(uint8_t* rtp, | |
90 size_t length, | |
91 const rtc::PacketTimeUpdateParams& packet_time_params) { | |
92 // If there is no key, return. | |
93 if (packet_time_params.srtp_auth_key.empty()) { | |
94 return; | |
95 } | |
96 | |
97 size_t tag_length = packet_time_params.srtp_auth_tag_len; | |
98 | |
99 // ROC (rollover counter) is at the beginning of the auth tag. | |
100 const size_t kRocLength = 4; | |
101 if (tag_length < kRocLength || tag_length > length) { | |
102 RTC_NOTREACHED(); | |
103 return; | |
104 } | |
105 | |
106 uint8_t* auth_tag = rtp + (length - tag_length); | |
107 | |
108 // We should have a fake HMAC value @ auth_tag. | |
109 RTC_DCHECK_EQ(0, memcmp(auth_tag, kFakeAuthTag, tag_length)); | |
110 | |
111 // Copy ROC after end of rtp packet. | |
112 memcpy(auth_tag, &packet_time_params.srtp_packet_index, kRocLength); | |
113 // Authentication of a RTP packet will have RTP packet + ROC size. | |
114 int auth_required_length = length - tag_length + kRocLength; | |
115 | |
116 uint8_t output[64]; | |
117 size_t result = rtc::ComputeHmac( | |
118 rtc::DIGEST_SHA_1, &packet_time_params.srtp_auth_key[0], | |
119 packet_time_params.srtp_auth_key.size(), rtp, | |
120 auth_required_length, output, sizeof(output)); | |
121 | |
122 if (result < tag_length) { | |
123 RTC_NOTREACHED(); | |
124 return; | |
125 } | |
126 | |
127 // Copy HMAC from output to packet. This is required as auth tag length | |
128 // may not be equal to the actual HMAC length. | |
129 memcpy(auth_tag, output, tag_length); | |
130 } | |
131 | |
132 } | |
39 | 133 |
40 bool GetUint8(const void* data, size_t offset, int* value) { | 134 bool GetUint8(const void* data, size_t offset, int* value) { |
41 if (!data || !value) { | 135 if (!data || !value) { |
42 return false; | 136 return false; |
43 } | 137 } |
44 *value = *(static_cast<const uint8_t*>(data) + offset); | 138 *value = *(static_cast<const uint8_t*>(data) + offset); |
45 return true; | 139 return true; |
46 } | 140 } |
47 | 141 |
48 bool GetUint16(const void* data, size_t offset, int* value) { | 142 bool GetUint16(const void* data, size_t offset, int* value) { |
(...skipping 144 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... | |
193 if (len < kMinRtpPacketLen) | 287 if (len < kMinRtpPacketLen) |
194 return false; | 288 return false; |
195 | 289 |
196 return (static_cast<const uint8_t*>(data)[0] >> 6) == kRtpVersion; | 290 return (static_cast<const uint8_t*>(data)[0] >> 6) == kRtpVersion; |
197 } | 291 } |
198 | 292 |
199 bool IsValidRtpPayloadType(int payload_type) { | 293 bool IsValidRtpPayloadType(int payload_type) { |
200 return payload_type >= 0 && payload_type <= 127; | 294 return payload_type >= 0 && payload_type <= 127; |
201 } | 295 } |
202 | 296 |
297 bool ValidateRtpHeader(const uint8_t* rtp, | |
298 size_t length, | |
299 size_t* header_length) { | |
300 if (header_length) { | |
301 *header_length = 0; | |
302 } | |
303 | |
304 if (length < kMinRtpPacketLen) { | |
305 return false; | |
306 } | |
307 | |
308 size_t cc_count = rtp[0] & 0x0F; | |
309 size_t header_length_without_extension = kMinRtpPacketLen + 4 * cc_count; | |
310 if (header_length_without_extension > length) { | |
311 return false; | |
312 } | |
313 | |
314 // If extension bit is not set, we are done with header processing, as input | |
315 // length is verified above. | |
316 if (!(rtp[0] & 0x10)) { | |
317 if (header_length) | |
318 *header_length = header_length_without_extension; | |
319 | |
320 return true; | |
321 } | |
322 | |
323 rtp += header_length_without_extension; | |
324 | |
325 if (header_length_without_extension + kRtpExtensionHeaderLen > length) { | |
326 return false; | |
327 } | |
328 | |
329 // Getting extension profile length. | |
330 // Length is in 32 bit words. | |
331 uint16_t extension_length_in_32bits = rtc::GetBE16(rtp + 2); | |
332 size_t extension_length = extension_length_in_32bits * 4; | |
333 | |
334 size_t rtp_header_length = extension_length + | |
335 header_length_without_extension + | |
336 kRtpExtensionHeaderLen; | |
337 | |
338 // Verify input length against total header size. | |
339 if (rtp_header_length > length) { | |
340 return false; | |
341 } | |
342 | |
343 if (header_length) { | |
344 *header_length = rtp_header_length; | |
345 } | |
346 return true; | |
347 } | |
348 | |
349 // ValidateRtpHeader() must be called before this method to make sure, we have | |
350 // a sane rtp packet. | |
351 bool UpdateRtpAbsSendTimeExtension(uint8_t* rtp, | |
352 size_t length, | |
353 int extension_id, | |
354 uint64_t time_us) { | |
355 // 0 1 2 3 | |
356 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
357 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
358 // |V=2|P|X| CC |M| PT | sequence number | | |
359 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
360 // | timestamp | | |
361 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
362 // | synchronization source (SSRC) identifier | | |
363 // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
364 // | contributing source (CSRC) identifiers | | |
365 // | .... | | |
366 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
367 | |
368 // Return if extension bit is not set. | |
369 if (!(rtp[0] & 0x10)) { | |
370 return true; | |
371 } | |
372 | |
373 size_t cc_count = rtp[0] & 0x0F; | |
374 size_t header_length_without_extension = kMinRtpPacketLen + 4 * cc_count; | |
375 | |
376 rtp += header_length_without_extension; | |
377 | |
378 // Getting extension profile ID and length. | |
379 uint16_t profile_id = rtc::GetBE16(rtp); | |
380 // Length is in 32 bit words. | |
381 uint16_t extension_length_in_32bits = rtc::GetBE16(rtp + 2); | |
382 size_t extension_length = extension_length_in_32bits * 4; | |
383 | |
384 rtp += kRtpExtensionHeaderLen; // Moving past extension header. | |
385 | |
386 bool found = false; | |
387 // WebRTC is using one byte header extension. | |
388 // TODO(mallinath) - Handle two byte header extension. | |
389 if (profile_id == 0xBEDE) { // OneByte extension header | |
390 // 0 | |
391 // 0 1 2 3 4 5 6 7 | |
392 // +-+-+-+-+-+-+-+-+ | |
393 // | ID |length | | |
394 // +-+-+-+-+-+-+-+-+ | |
395 | |
396 // 0 1 2 3 | |
397 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 | |
398 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
399 // | 0xBE | 0xDE | length=3 | | |
400 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
401 // | ID | L=0 | data | ID | L=1 | data... | |
402 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
403 // ...data | 0 (pad) | 0 (pad) | ID | L=3 | | |
404 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
405 // | data | | |
406 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
407 const uint8_t* extension_start = rtp; | |
408 const uint8_t* extension_end = extension_start + extension_length; | |
409 | |
410 while (rtp < extension_end) { | |
411 const int id = (*rtp & 0xF0) >> 4; | |
412 const size_t length = (*rtp & 0x0F) + 1; | |
413 if (rtp + kOneByteExtensionHeaderLen + length > extension_end) { | |
414 return false; | |
415 } | |
416 // The 4-bit length is the number minus one of data bytes of this header | |
417 // extension element following the one-byte header. | |
418 if (id == extension_id) { | |
419 UpdateAbsSendTimeExtensionValue(rtp + kOneByteExtensionHeaderLen, | |
420 length, time_us); | |
421 found = true; | |
422 break; | |
423 } | |
424 rtp += kOneByteExtensionHeaderLen + length; | |
425 // Counting padding bytes. | |
426 while ((rtp < extension_end) && (*rtp == 0)) { | |
427 ++rtp; | |
428 } | |
429 } | |
430 } | |
431 return found; | |
432 } | |
433 | |
434 bool ApplyPacketOptions(uint8_t* data, | |
435 size_t length, | |
436 const rtc::PacketTimeUpdateParams& packet_time_params, | |
437 uint64_t time_us) { | |
438 RTC_DCHECK(data); | |
439 RTC_DCHECK(length); | |
440 | |
441 // if there is no valid |rtp_sendtime_extension_id| and |srtp_auth_key| in | |
442 // PacketOptions, nothing to be updated in this packet. | |
443 if (packet_time_params.rtp_sendtime_extension_id == -1 && | |
444 packet_time_params.srtp_auth_key.empty()) { | |
445 return true; | |
446 } | |
447 | |
448 // If there is a srtp auth key present then the packet must be an RTP packet. | |
449 // RTP packet may have been wrapped in a TURN Channel Data or TURN send | |
450 // indication. | |
451 size_t rtp_start_pos; | |
452 size_t rtp_length; | |
453 if (!UnwrapTurnPacket(data, length, &rtp_start_pos, &rtp_length)) { | |
454 RTC_NOTREACHED(); | |
455 return false; | |
456 } | |
457 | |
458 // Making sure we have a valid RTP packet at the end. | |
459 if (!IsRtpPacket(data + rtp_start_pos, rtp_length) || | |
460 !ValidateRtpHeader(data + rtp_start_pos, rtp_length, nullptr)) { | |
461 RTC_NOTREACHED(); | |
462 return false; | |
463 } | |
464 | |
465 uint8_t* start = data + rtp_start_pos; | |
466 // If packet option has non default value (-1) for sendtime extension id, | |
467 // then we should parse the rtp packet to update the timestamp. Otherwise | |
468 // just calculate HMAC and update packet with it. | |
469 if (packet_time_params.rtp_sendtime_extension_id != -1) { | |
470 UpdateRtpAbsSendTimeExtension(start, rtp_length, | |
471 packet_time_params.rtp_sendtime_extension_id, | |
472 time_us); | |
473 } | |
474 | |
475 UpdateRtpAuthTag(start, rtp_length, packet_time_params); | |
476 return true; | |
477 } | |
478 | |
203 } // namespace cricket | 479 } // namespace cricket |
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