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