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23e7e3ae JVH |
1 | /** |
2 | * Copyright (C) 2011-2012 Juho Vähä-Herttua | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * This library is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | */ | |
14 | ||
2340bcd3 JVH |
15 | #include <stdlib.h> |
16 | #include <string.h> | |
17 | #include <assert.h> | |
18 | #include <math.h> | |
19 | ||
20 | #include "raop_buffer.h" | |
21 | #include "raop_rtp.h" | |
22 | #include "utils.h" | |
23 | ||
24 | #include <stdint.h> | |
25 | #include "crypto/crypto.h" | |
26 | #include "alac/alac.h" | |
27 | ||
28 | #define RAOP_BUFFER_LENGTH 16 | |
29 | ||
30 | typedef struct { | |
31 | /* Packet available */ | |
32 | int available; | |
33 | ||
34 | /* RTP header */ | |
35 | unsigned char flags; | |
36 | unsigned char type; | |
37 | unsigned short seqnum; | |
38 | unsigned int timestamp; | |
39 | unsigned int ssrc; | |
40 | ||
41 | /* Audio buffer of valid length */ | |
42 | int audio_buffer_size; | |
43 | int audio_buffer_len; | |
44 | void *audio_buffer; | |
45 | } raop_buffer_entry_t; | |
46 | ||
47 | struct raop_buffer_s { | |
48 | /* AES key and IV */ | |
49 | unsigned char aeskey[RAOP_AESKEY_LEN]; | |
50 | unsigned char aesiv[RAOP_AESIV_LEN]; | |
51 | ||
52 | /* ALAC decoder */ | |
53 | ALACSpecificConfig alacConfig; | |
54 | alac_file *alac; | |
55 | ||
56 | /* First and last seqnum */ | |
57 | int is_empty; | |
58 | unsigned short first_seqnum; | |
59 | unsigned short last_seqnum; | |
60 | ||
61 | /* RTP buffer entries */ | |
62 | raop_buffer_entry_t entries[RAOP_BUFFER_LENGTH]; | |
63 | ||
64 | /* Buffer of all audio buffers */ | |
65 | int buffer_size; | |
66 | void *buffer; | |
67 | }; | |
68 | ||
69 | ||
70 | ||
71 | static int | |
72 | get_fmtp_info(ALACSpecificConfig *config, const char *fmtp) | |
73 | { | |
74 | int intarr[12]; | |
75 | char *strptr; | |
76 | int i; | |
77 | ||
78 | /* Parse fmtp string to integers */ | |
79 | strptr = strdup(fmtp); | |
80 | for (i=0; i<12; i++) { | |
81 | if (strptr == NULL) { | |
82 | free(strptr); | |
83 | return -1; | |
84 | } | |
85 | intarr[i] = atoi(utils_strsep(&strptr, " ")); | |
86 | } | |
87 | free(strptr); | |
88 | strptr = NULL; | |
89 | ||
90 | /* Fill the config struct */ | |
91 | config->frameLength = intarr[1]; | |
92 | config->compatibleVersion = intarr[2]; | |
93 | config->bitDepth = intarr[3]; | |
94 | config->pb = intarr[4]; | |
95 | config->mb = intarr[5]; | |
96 | config->kb = intarr[6]; | |
97 | config->numChannels = intarr[7]; | |
98 | config->maxRun = intarr[8]; | |
99 | config->maxFrameBytes = intarr[9]; | |
100 | config->avgBitRate = intarr[10]; | |
101 | config->sampleRate = intarr[11]; | |
102 | ||
103 | /* Validate supported audio types */ | |
104 | if (config->bitDepth != 16) { | |
105 | return -2; | |
106 | } | |
107 | if (config->numChannels != 2) { | |
108 | return -3; | |
109 | } | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | static void | |
115 | set_decoder_info(alac_file *alac, ALACSpecificConfig *config) | |
116 | { | |
117 | unsigned char decoder_info[48]; | |
118 | memset(decoder_info, 0, sizeof(decoder_info)); | |
119 | ||
120 | #define SET_UINT16(buf, value)do{\ | |
121 | (buf)[0] = (unsigned char)((value) >> 8);\ | |
122 | (buf)[1] = (unsigned char)(value);\ | |
123 | }while(0) | |
124 | ||
125 | #define SET_UINT32(buf, value)do{\ | |
126 | (buf)[0] = (unsigned char)((value) >> 24);\ | |
127 | (buf)[1] = (unsigned char)((value) >> 16);\ | |
128 | (buf)[2] = (unsigned char)((value) >> 8);\ | |
129 | (buf)[3] = (unsigned char)(value);\ | |
130 | }while(0) | |
131 | ||
132 | /* Construct decoder info buffer */ | |
133 | SET_UINT32(&decoder_info[24], config->frameLength); | |
134 | decoder_info[28] = config->compatibleVersion; | |
135 | decoder_info[29] = config->bitDepth; | |
136 | decoder_info[30] = config->pb; | |
137 | decoder_info[31] = config->mb; | |
138 | decoder_info[32] = config->kb; | |
139 | decoder_info[33] = config->numChannels; | |
140 | SET_UINT16(&decoder_info[34], config->maxRun); | |
141 | SET_UINT32(&decoder_info[36], config->maxFrameBytes); | |
142 | SET_UINT32(&decoder_info[40], config->avgBitRate); | |
143 | SET_UINT32(&decoder_info[44], config->sampleRate); | |
144 | alac_set_info(alac, (char *) decoder_info); | |
145 | } | |
146 | ||
147 | raop_buffer_t * | |
148 | raop_buffer_init(const char *fmtp, | |
149 | const unsigned char *aeskey, | |
150 | const unsigned char *aesiv) | |
151 | { | |
152 | raop_buffer_t *raop_buffer; | |
153 | int audio_buffer_size; | |
154 | ALACSpecificConfig *alacConfig; | |
155 | int i; | |
156 | ||
157 | assert(fmtp); | |
158 | assert(aeskey); | |
159 | assert(aesiv); | |
160 | ||
161 | raop_buffer = calloc(1, sizeof(raop_buffer_t)); | |
162 | if (!raop_buffer) { | |
163 | return NULL; | |
164 | } | |
165 | ||
166 | /* Parse fmtp information */ | |
167 | alacConfig = &raop_buffer->alacConfig; | |
168 | if (get_fmtp_info(alacConfig, fmtp) < 0) { | |
169 | free(raop_buffer); | |
170 | return NULL; | |
171 | } | |
172 | ||
173 | /* Allocate the output audio buffers */ | |
174 | audio_buffer_size = alacConfig->frameLength * | |
175 | alacConfig->numChannels * | |
176 | alacConfig->bitDepth/8; | |
177 | raop_buffer->buffer_size = audio_buffer_size * | |
178 | RAOP_BUFFER_LENGTH; | |
179 | raop_buffer->buffer = malloc(raop_buffer->buffer_size); | |
180 | if (!raop_buffer->buffer) { | |
181 | free(raop_buffer); | |
182 | return NULL; | |
183 | } | |
184 | for (i=0; i<RAOP_BUFFER_LENGTH; i++) { | |
185 | raop_buffer_entry_t *entry = &raop_buffer->entries[i]; | |
186 | entry->audio_buffer_size = audio_buffer_size; | |
187 | entry->audio_buffer_len = 0; | |
188 | entry->audio_buffer = raop_buffer->buffer+i*audio_buffer_size; | |
189 | } | |
190 | ||
191 | /* Initialize ALAC decoder */ | |
192 | raop_buffer->alac = create_alac(alacConfig->bitDepth, | |
193 | alacConfig->numChannels); | |
194 | if (!raop_buffer->alac) { | |
195 | free(raop_buffer->buffer); | |
196 | free(raop_buffer); | |
197 | return NULL; | |
198 | } | |
199 | set_decoder_info(raop_buffer->alac, alacConfig); | |
200 | ||
201 | /* Initialize AES keys */ | |
202 | memcpy(raop_buffer->aeskey, aeskey, RAOP_AESKEY_LEN); | |
203 | memcpy(raop_buffer->aesiv, aesiv, RAOP_AESIV_LEN); | |
204 | ||
205 | /* Mark buffer as empty */ | |
206 | raop_buffer->is_empty = 1; | |
207 | return raop_buffer; | |
208 | } | |
209 | ||
210 | void | |
211 | raop_buffer_destroy(raop_buffer_t *raop_buffer) | |
212 | { | |
213 | if (raop_buffer) { | |
214 | free(raop_buffer->buffer); | |
215 | free(raop_buffer->alac); | |
216 | free(raop_buffer); | |
217 | } | |
218 | } | |
219 | ||
220 | const ALACSpecificConfig * | |
221 | raop_buffer_get_config(raop_buffer_t *raop_buffer) | |
222 | { | |
223 | assert(raop_buffer); | |
224 | ||
225 | return &raop_buffer->alacConfig; | |
226 | } | |
227 | ||
228 | static short | |
229 | seqnum_cmp(unsigned short s1, unsigned short s2) | |
230 | { | |
231 | return (s1 - s2); | |
232 | } | |
233 | ||
234 | int | |
235 | raop_buffer_queue(raop_buffer_t *raop_buffer, unsigned char *data, unsigned short datalen, int use_seqnum) | |
236 | { | |
237 | unsigned char packetbuf[RAOP_PACKET_LEN]; | |
238 | unsigned short seqnum; | |
239 | raop_buffer_entry_t *entry; | |
240 | int encryptedlen; | |
241 | AES_CTX aes_ctx; | |
242 | int outputlen; | |
243 | ||
244 | assert(raop_buffer); | |
245 | ||
246 | /* Check packet data length is valid */ | |
247 | if (datalen < 12 || datalen > RAOP_PACKET_LEN) { | |
248 | return -1; | |
249 | } | |
250 | ||
251 | /* Get correct seqnum for the packet */ | |
252 | if (use_seqnum) { | |
253 | seqnum = (data[2] << 8) | data[3]; | |
254 | } else { | |
255 | seqnum = raop_buffer->first_seqnum; | |
256 | } | |
257 | ||
258 | /* If this packet is too late, just skip it */ | |
259 | if (!raop_buffer->is_empty && seqnum_cmp(seqnum, raop_buffer->first_seqnum) < 0) { | |
260 | return 0; | |
261 | } | |
262 | ||
263 | /* Check that there is always space in the buffer, otherwise flush */ | |
264 | if (seqnum_cmp(seqnum, raop_buffer->first_seqnum+RAOP_BUFFER_LENGTH) >= 0) { | |
265 | raop_buffer_flush(raop_buffer, seqnum); | |
266 | } | |
267 | ||
268 | /* Get entry corresponding our seqnum */ | |
269 | entry = &raop_buffer->entries[seqnum % RAOP_BUFFER_LENGTH]; | |
270 | if (entry->available && seqnum_cmp(entry->seqnum, seqnum) == 0) { | |
271 | /* Packet resend, we can safely ignore */ | |
272 | return 0; | |
273 | } | |
274 | ||
275 | /* Update the raop_buffer entry header */ | |
276 | entry->flags = data[0]; | |
277 | entry->type = data[1]; | |
278 | entry->seqnum = seqnum; | |
279 | entry->timestamp = (data[4] << 24) | (data[5] << 16) | | |
280 | (data[6] << 8) | data[7]; | |
281 | entry->ssrc = (data[8] << 24) | (data[9] << 16) | | |
282 | (data[10] << 8) | data[11]; | |
283 | entry->available = 1; | |
284 | ||
285 | /* Decrypt audio data */ | |
286 | encryptedlen = (datalen-12)/16*16; | |
287 | AES_set_key(&aes_ctx, raop_buffer->aeskey, raop_buffer->aesiv, AES_MODE_128); | |
288 | AES_convert_key(&aes_ctx); | |
289 | AES_cbc_decrypt(&aes_ctx, &data[12], packetbuf, encryptedlen); | |
290 | memcpy(packetbuf+encryptedlen, &data[12+encryptedlen], datalen-12-encryptedlen); | |
291 | ||
292 | /* Decode ALAC audio data */ | |
293 | outputlen = entry->audio_buffer_size; | |
294 | decode_frame(raop_buffer->alac, packetbuf, entry->audio_buffer, &outputlen); | |
295 | entry->audio_buffer_len = outputlen; | |
296 | ||
297 | /* Update the raop_buffer seqnums */ | |
298 | if (raop_buffer->is_empty) { | |
299 | raop_buffer->first_seqnum = seqnum; | |
300 | raop_buffer->last_seqnum = seqnum; | |
301 | raop_buffer->is_empty = 0; | |
302 | } | |
303 | if (seqnum_cmp(seqnum, raop_buffer->last_seqnum) > 0) { | |
304 | raop_buffer->last_seqnum = seqnum; | |
305 | } | |
306 | return 1; | |
307 | } | |
308 | ||
309 | const void * | |
310 | raop_buffer_dequeue(raop_buffer_t *raop_buffer, int *length, int no_resend) | |
311 | { | |
312 | short buflen; | |
313 | raop_buffer_entry_t *entry; | |
314 | ||
315 | /* Calculate number of entries in the current buffer */ | |
316 | buflen = seqnum_cmp(raop_buffer->last_seqnum, raop_buffer->first_seqnum)+1; | |
317 | ||
318 | /* Cannot dequeue from empty buffer */ | |
319 | if (raop_buffer->is_empty || buflen <= 0) { | |
320 | return NULL; | |
321 | } | |
322 | ||
323 | /* Get the first buffer entry for inspection */ | |
324 | entry = &raop_buffer->entries[raop_buffer->first_seqnum % RAOP_BUFFER_LENGTH]; | |
325 | if (no_resend) { | |
326 | /* If we do no resends, always return the first entry */ | |
327 | } else if (!entry->available) { | |
328 | /* Check how much we have space left in the buffer */ | |
329 | if (buflen < RAOP_BUFFER_LENGTH) { | |
330 | /* Return nothing and hope resend gets on time */ | |
331 | return NULL; | |
332 | } | |
333 | /* Risk of buffer overrun, return empty buffer */ | |
334 | } | |
335 | ||
336 | /* Update buffer and validate entry */ | |
337 | raop_buffer->first_seqnum += 1; | |
338 | if (!entry->available) { | |
339 | /* Return an empty audio buffer to skip audio */ | |
340 | *length = entry->audio_buffer_size; | |
341 | memset(entry->audio_buffer, 0, *length); | |
342 | return entry->audio_buffer; | |
343 | } | |
344 | entry->available = 0; | |
345 | ||
346 | /* Return entry audio buffer */ | |
347 | *length = entry->audio_buffer_len; | |
348 | entry->audio_buffer_len = 0; | |
349 | return entry->audio_buffer; | |
350 | } | |
351 | ||
352 | void | |
353 | raop_buffer_handle_resends(raop_buffer_t *raop_buffer, raop_resend_cb_t resend_cb, void *opaque) | |
354 | { | |
355 | raop_buffer_entry_t *entry; | |
356 | ||
357 | assert(raop_buffer); | |
358 | assert(resend_cb); | |
359 | ||
360 | if (seqnum_cmp(raop_buffer->first_seqnum, raop_buffer->last_seqnum) < 0) { | |
361 | int seqnum, count; | |
362 | ||
363 | for (seqnum=raop_buffer->first_seqnum; seqnum_cmp(seqnum, raop_buffer->last_seqnum)<0; seqnum++) { | |
364 | entry = &raop_buffer->entries[seqnum % RAOP_BUFFER_LENGTH]; | |
365 | if (entry->available) { | |
366 | break; | |
367 | } | |
368 | } | |
369 | if (seqnum_cmp(seqnum, raop_buffer->first_seqnum) == 0) { | |
370 | return; | |
371 | } | |
372 | count = seqnum_cmp(seqnum, raop_buffer->first_seqnum); | |
373 | resend_cb(opaque, raop_buffer->first_seqnum, count); | |
374 | } | |
375 | } | |
376 | ||
377 | void | |
378 | raop_buffer_flush(raop_buffer_t *raop_buffer, int next_seq) | |
379 | { | |
380 | int i; | |
381 | ||
382 | assert(raop_buffer); | |
383 | ||
384 | for (i=0; i<RAOP_BUFFER_LENGTH; i++) { | |
385 | raop_buffer->entries[i].available = 0; | |
386 | raop_buffer->entries[i].audio_buffer_len = 0; | |
387 | } | |
388 | if (next_seq < 0 || next_seq > 0xffff) { | |
389 | raop_buffer->is_empty = 1; | |
390 | } else { | |
391 | raop_buffer->first_seqnum = next_seq; | |
392 | raop_buffer->last_seqnum = next_seq-1; | |
393 | } | |
394 | } |