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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]; | |
a5670bb8 | 75 | char *original; |
2340bcd3 JVH |
76 | char *strptr; |
77 | int i; | |
78 | ||
79 | /* Parse fmtp string to integers */ | |
a5670bb8 | 80 | original = strptr = strdup(fmtp); |
2340bcd3 JVH |
81 | for (i=0; i<12; i++) { |
82 | if (strptr == NULL) { | |
a5670bb8 | 83 | free(original); |
2340bcd3 JVH |
84 | return -1; |
85 | } | |
86 | intarr[i] = atoi(utils_strsep(&strptr, " ")); | |
87 | } | |
a5670bb8 JVH |
88 | free(original); |
89 | original = strptr = NULL; | |
2340bcd3 JVH |
90 | |
91 | /* Fill the config struct */ | |
92 | config->frameLength = intarr[1]; | |
93 | config->compatibleVersion = intarr[2]; | |
94 | config->bitDepth = intarr[3]; | |
95 | config->pb = intarr[4]; | |
96 | config->mb = intarr[5]; | |
97 | config->kb = intarr[6]; | |
98 | config->numChannels = intarr[7]; | |
99 | config->maxRun = intarr[8]; | |
100 | config->maxFrameBytes = intarr[9]; | |
101 | config->avgBitRate = intarr[10]; | |
102 | config->sampleRate = intarr[11]; | |
103 | ||
104 | /* Validate supported audio types */ | |
105 | if (config->bitDepth != 16) { | |
106 | return -2; | |
107 | } | |
108 | if (config->numChannels != 2) { | |
109 | return -3; | |
110 | } | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | static void | |
116 | set_decoder_info(alac_file *alac, ALACSpecificConfig *config) | |
117 | { | |
118 | unsigned char decoder_info[48]; | |
119 | memset(decoder_info, 0, sizeof(decoder_info)); | |
120 | ||
121 | #define SET_UINT16(buf, value)do{\ | |
122 | (buf)[0] = (unsigned char)((value) >> 8);\ | |
123 | (buf)[1] = (unsigned char)(value);\ | |
124 | }while(0) | |
125 | ||
126 | #define SET_UINT32(buf, value)do{\ | |
127 | (buf)[0] = (unsigned char)((value) >> 24);\ | |
128 | (buf)[1] = (unsigned char)((value) >> 16);\ | |
129 | (buf)[2] = (unsigned char)((value) >> 8);\ | |
130 | (buf)[3] = (unsigned char)(value);\ | |
131 | }while(0) | |
132 | ||
133 | /* Construct decoder info buffer */ | |
134 | SET_UINT32(&decoder_info[24], config->frameLength); | |
135 | decoder_info[28] = config->compatibleVersion; | |
136 | decoder_info[29] = config->bitDepth; | |
137 | decoder_info[30] = config->pb; | |
138 | decoder_info[31] = config->mb; | |
139 | decoder_info[32] = config->kb; | |
140 | decoder_info[33] = config->numChannels; | |
141 | SET_UINT16(&decoder_info[34], config->maxRun); | |
142 | SET_UINT32(&decoder_info[36], config->maxFrameBytes); | |
143 | SET_UINT32(&decoder_info[40], config->avgBitRate); | |
144 | SET_UINT32(&decoder_info[44], config->sampleRate); | |
145 | alac_set_info(alac, (char *) decoder_info); | |
146 | } | |
147 | ||
148 | raop_buffer_t * | |
149 | raop_buffer_init(const char *fmtp, | |
150 | const unsigned char *aeskey, | |
151 | const unsigned char *aesiv) | |
152 | { | |
153 | raop_buffer_t *raop_buffer; | |
154 | int audio_buffer_size; | |
155 | ALACSpecificConfig *alacConfig; | |
156 | int i; | |
157 | ||
158 | assert(fmtp); | |
159 | assert(aeskey); | |
160 | assert(aesiv); | |
161 | ||
162 | raop_buffer = calloc(1, sizeof(raop_buffer_t)); | |
163 | if (!raop_buffer) { | |
164 | return NULL; | |
165 | } | |
166 | ||
167 | /* Parse fmtp information */ | |
168 | alacConfig = &raop_buffer->alacConfig; | |
169 | if (get_fmtp_info(alacConfig, fmtp) < 0) { | |
170 | free(raop_buffer); | |
171 | return NULL; | |
172 | } | |
173 | ||
174 | /* Allocate the output audio buffers */ | |
175 | audio_buffer_size = alacConfig->frameLength * | |
176 | alacConfig->numChannels * | |
177 | alacConfig->bitDepth/8; | |
178 | raop_buffer->buffer_size = audio_buffer_size * | |
179 | RAOP_BUFFER_LENGTH; | |
180 | raop_buffer->buffer = malloc(raop_buffer->buffer_size); | |
181 | if (!raop_buffer->buffer) { | |
182 | free(raop_buffer); | |
183 | return NULL; | |
184 | } | |
185 | for (i=0; i<RAOP_BUFFER_LENGTH; i++) { | |
186 | raop_buffer_entry_t *entry = &raop_buffer->entries[i]; | |
187 | entry->audio_buffer_size = audio_buffer_size; | |
188 | entry->audio_buffer_len = 0; | |
566c9bf8 | 189 | entry->audio_buffer = (char *)raop_buffer->buffer+i*audio_buffer_size; |
2340bcd3 JVH |
190 | } |
191 | ||
192 | /* Initialize ALAC decoder */ | |
193 | raop_buffer->alac = create_alac(alacConfig->bitDepth, | |
194 | alacConfig->numChannels); | |
195 | if (!raop_buffer->alac) { | |
196 | free(raop_buffer->buffer); | |
197 | free(raop_buffer); | |
198 | return NULL; | |
199 | } | |
200 | set_decoder_info(raop_buffer->alac, alacConfig); | |
201 | ||
202 | /* Initialize AES keys */ | |
203 | memcpy(raop_buffer->aeskey, aeskey, RAOP_AESKEY_LEN); | |
204 | memcpy(raop_buffer->aesiv, aesiv, RAOP_AESIV_LEN); | |
205 | ||
206 | /* Mark buffer as empty */ | |
207 | raop_buffer->is_empty = 1; | |
208 | return raop_buffer; | |
209 | } | |
210 | ||
211 | void | |
212 | raop_buffer_destroy(raop_buffer_t *raop_buffer) | |
213 | { | |
214 | if (raop_buffer) { | |
982a0c26 | 215 | destroy_alac(raop_buffer->alac); |
2340bcd3 | 216 | free(raop_buffer->buffer); |
2340bcd3 JVH |
217 | free(raop_buffer); |
218 | } | |
219 | } | |
220 | ||
221 | const ALACSpecificConfig * | |
222 | raop_buffer_get_config(raop_buffer_t *raop_buffer) | |
223 | { | |
224 | assert(raop_buffer); | |
225 | ||
226 | return &raop_buffer->alacConfig; | |
227 | } | |
228 | ||
229 | static short | |
230 | seqnum_cmp(unsigned short s1, unsigned short s2) | |
231 | { | |
232 | return (s1 - s2); | |
233 | } | |
234 | ||
235 | int | |
236 | raop_buffer_queue(raop_buffer_t *raop_buffer, unsigned char *data, unsigned short datalen, int use_seqnum) | |
237 | { | |
238 | unsigned char packetbuf[RAOP_PACKET_LEN]; | |
239 | unsigned short seqnum; | |
240 | raop_buffer_entry_t *entry; | |
241 | int encryptedlen; | |
242 | AES_CTX aes_ctx; | |
243 | int outputlen; | |
244 | ||
245 | assert(raop_buffer); | |
246 | ||
247 | /* Check packet data length is valid */ | |
248 | if (datalen < 12 || datalen > RAOP_PACKET_LEN) { | |
249 | return -1; | |
250 | } | |
251 | ||
252 | /* Get correct seqnum for the packet */ | |
253 | if (use_seqnum) { | |
254 | seqnum = (data[2] << 8) | data[3]; | |
255 | } else { | |
256 | seqnum = raop_buffer->first_seqnum; | |
257 | } | |
258 | ||
259 | /* If this packet is too late, just skip it */ | |
260 | if (!raop_buffer->is_empty && seqnum_cmp(seqnum, raop_buffer->first_seqnum) < 0) { | |
261 | return 0; | |
262 | } | |
263 | ||
264 | /* Check that there is always space in the buffer, otherwise flush */ | |
265 | if (seqnum_cmp(seqnum, raop_buffer->first_seqnum+RAOP_BUFFER_LENGTH) >= 0) { | |
266 | raop_buffer_flush(raop_buffer, seqnum); | |
267 | } | |
268 | ||
269 | /* Get entry corresponding our seqnum */ | |
270 | entry = &raop_buffer->entries[seqnum % RAOP_BUFFER_LENGTH]; | |
271 | if (entry->available && seqnum_cmp(entry->seqnum, seqnum) == 0) { | |
272 | /* Packet resend, we can safely ignore */ | |
273 | return 0; | |
274 | } | |
275 | ||
276 | /* Update the raop_buffer entry header */ | |
277 | entry->flags = data[0]; | |
278 | entry->type = data[1]; | |
279 | entry->seqnum = seqnum; | |
280 | entry->timestamp = (data[4] << 24) | (data[5] << 16) | | |
281 | (data[6] << 8) | data[7]; | |
282 | entry->ssrc = (data[8] << 24) | (data[9] << 16) | | |
283 | (data[10] << 8) | data[11]; | |
284 | entry->available = 1; | |
285 | ||
286 | /* Decrypt audio data */ | |
287 | encryptedlen = (datalen-12)/16*16; | |
288 | AES_set_key(&aes_ctx, raop_buffer->aeskey, raop_buffer->aesiv, AES_MODE_128); | |
289 | AES_convert_key(&aes_ctx); | |
290 | AES_cbc_decrypt(&aes_ctx, &data[12], packetbuf, encryptedlen); | |
291 | memcpy(packetbuf+encryptedlen, &data[12+encryptedlen], datalen-12-encryptedlen); | |
292 | ||
293 | /* Decode ALAC audio data */ | |
294 | outputlen = entry->audio_buffer_size; | |
295 | decode_frame(raop_buffer->alac, packetbuf, entry->audio_buffer, &outputlen); | |
296 | entry->audio_buffer_len = outputlen; | |
297 | ||
298 | /* Update the raop_buffer seqnums */ | |
299 | if (raop_buffer->is_empty) { | |
300 | raop_buffer->first_seqnum = seqnum; | |
301 | raop_buffer->last_seqnum = seqnum; | |
302 | raop_buffer->is_empty = 0; | |
303 | } | |
304 | if (seqnum_cmp(seqnum, raop_buffer->last_seqnum) > 0) { | |
305 | raop_buffer->last_seqnum = seqnum; | |
306 | } | |
307 | return 1; | |
308 | } | |
309 | ||
310 | const void * | |
311 | raop_buffer_dequeue(raop_buffer_t *raop_buffer, int *length, int no_resend) | |
312 | { | |
313 | short buflen; | |
314 | raop_buffer_entry_t *entry; | |
315 | ||
316 | /* Calculate number of entries in the current buffer */ | |
317 | buflen = seqnum_cmp(raop_buffer->last_seqnum, raop_buffer->first_seqnum)+1; | |
318 | ||
319 | /* Cannot dequeue from empty buffer */ | |
320 | if (raop_buffer->is_empty || buflen <= 0) { | |
321 | return NULL; | |
322 | } | |
323 | ||
324 | /* Get the first buffer entry for inspection */ | |
325 | entry = &raop_buffer->entries[raop_buffer->first_seqnum % RAOP_BUFFER_LENGTH]; | |
326 | if (no_resend) { | |
327 | /* If we do no resends, always return the first entry */ | |
328 | } else if (!entry->available) { | |
329 | /* Check how much we have space left in the buffer */ | |
330 | if (buflen < RAOP_BUFFER_LENGTH) { | |
331 | /* Return nothing and hope resend gets on time */ | |
332 | return NULL; | |
333 | } | |
334 | /* Risk of buffer overrun, return empty buffer */ | |
335 | } | |
336 | ||
337 | /* Update buffer and validate entry */ | |
338 | raop_buffer->first_seqnum += 1; | |
339 | if (!entry->available) { | |
340 | /* Return an empty audio buffer to skip audio */ | |
341 | *length = entry->audio_buffer_size; | |
342 | memset(entry->audio_buffer, 0, *length); | |
343 | return entry->audio_buffer; | |
344 | } | |
345 | entry->available = 0; | |
346 | ||
347 | /* Return entry audio buffer */ | |
348 | *length = entry->audio_buffer_len; | |
349 | entry->audio_buffer_len = 0; | |
350 | return entry->audio_buffer; | |
351 | } | |
352 | ||
353 | void | |
354 | raop_buffer_handle_resends(raop_buffer_t *raop_buffer, raop_resend_cb_t resend_cb, void *opaque) | |
355 | { | |
356 | raop_buffer_entry_t *entry; | |
357 | ||
358 | assert(raop_buffer); | |
359 | assert(resend_cb); | |
360 | ||
361 | if (seqnum_cmp(raop_buffer->first_seqnum, raop_buffer->last_seqnum) < 0) { | |
362 | int seqnum, count; | |
363 | ||
364 | for (seqnum=raop_buffer->first_seqnum; seqnum_cmp(seqnum, raop_buffer->last_seqnum)<0; seqnum++) { | |
365 | entry = &raop_buffer->entries[seqnum % RAOP_BUFFER_LENGTH]; | |
366 | if (entry->available) { | |
367 | break; | |
368 | } | |
369 | } | |
370 | if (seqnum_cmp(seqnum, raop_buffer->first_seqnum) == 0) { | |
371 | return; | |
372 | } | |
373 | count = seqnum_cmp(seqnum, raop_buffer->first_seqnum); | |
374 | resend_cb(opaque, raop_buffer->first_seqnum, count); | |
375 | } | |
376 | } | |
377 | ||
378 | void | |
379 | raop_buffer_flush(raop_buffer_t *raop_buffer, int next_seq) | |
380 | { | |
381 | int i; | |
382 | ||
383 | assert(raop_buffer); | |
384 | ||
385 | for (i=0; i<RAOP_BUFFER_LENGTH; i++) { | |
386 | raop_buffer->entries[i].available = 0; | |
387 | raop_buffer->entries[i].audio_buffer_len = 0; | |
388 | } | |
389 | if (next_seq < 0 || next_seq > 0xffff) { | |
390 | raop_buffer->is_empty = 1; | |
391 | } else { | |
392 | raop_buffer->first_seqnum = next_seq; | |
393 | raop_buffer->last_seqnum = next_seq-1; | |
394 | } | |
395 | } |