/*
  * Sony OpenMG (OMA) demuxer
  *

  * Copyright (c) 2008, 2013 Maxim Poliakovski

  *               2008 Benjamin Larsson

  *               2011 David Goldwich

  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * This is a demuxer for Sony OpenMG Music files
  *
  * Known file extensions: ".oma", "aa3"
  * The format of such files consists of three parts:

  * - "ea3" header carrying overall info and metadata. Except for starting with
  *   "ea" instead of "ID", it's an ID3v2 header.

  * - "EA3" header is a Sony-specific header containing information about
  *   the OpenMG file: codec type (usually ATRAC, can also be MP3 or WMA),
  *   codec specific info (packet size, sample rate, channels and so on)
  *   and DRM related info (file encryption, content id).
  * - Sound data organized in packets follow the EA3 header
  *   (can be encrypted using the Sony DRM!).
  *

  * Supported decoders: ATRAC3, ATRAC3+, MP3, LPCM

  */
 

 #include <inttypes.h>
 

 #include "libavutil/channel_layout.h"

 #include "avformat.h"

 #include "internal.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/des.h"

 #include "libavutil/mathematics.h"

 #include "oma.h"

 #include "pcm.h"

 #include "id3v2.h"

 static const uint64_t leaf_table[] = {
     0xd79e8283acea4620, 0x7a9762f445afd0d8,
     0x354d60a60b8c79f1, 0x584e1cde00b07aee,
     0x1573cd93da7df623, 0x47f98d79620dd535
 };
 
 typedef struct OMAContext {
     uint64_t content_start;
     int encrypted;
     uint16_t k_size;
     uint16_t e_size;
     uint16_t i_size;
     uint16_t s_size;
     uint32_t rid;
     uint8_t r_val[24];
     uint8_t n_val[24];
     uint8_t m_val[8];
     uint8_t s_val[8];
     uint8_t sm_val[8];
     uint8_t e_val[8];
     uint8_t iv[8];

     struct AVDES *av_des;

 
     int (*read_packet)(AVFormatContext *s, AVPacket *pkt);

 } OMAContext;
 

 static void hex_log(AVFormatContext *s, int level,
                     const char *name, const uint8_t *value, int len)

 {
     char buf[33];
     len = FFMIN(len, 16);
     if (av_log_get_level() < level)
         return;
     ff_data_to_hex(buf, value, len, 1);

     buf[len << 1] = '\0';

     av_log(s, level, "%s: %s\n", name, buf);
 }
 

 static int kset(AVFormatContext *s, const uint8_t *r_val, const uint8_t *n_val,
                 int len)

 {
     OMAContext *oc = s->priv_data;
 
     if (!r_val && !n_val)
         return -1;
 
     len = FFMIN(len, 16);
 
     /* use first 64 bits in the third round again */
     if (r_val) {
         if (r_val != oc->r_val) {
             memset(oc->r_val, 0, 24);
             memcpy(oc->r_val, r_val, len);
         }
         memcpy(&oc->r_val[16], r_val, 8);
     }
     if (n_val) {
         if (n_val != oc->n_val) {
             memset(oc->n_val, 0, 24);
             memcpy(oc->n_val, n_val, len);
         }
         memcpy(&oc->n_val[16], n_val, 8);
     }
 
     return 0;
 }
 

 #define OMA_RPROBE_M_VAL 48 + 1
 
 static int rprobe(AVFormatContext *s, uint8_t *enc_header, unsigned size,
                   const uint8_t *r_val)

 {
     OMAContext *oc = s->priv_data;
     unsigned int pos;

     struct AVDES *av_des;

     if (!enc_header || !r_val ||
         size < OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size ||
         size < OMA_RPROBE_M_VAL)

         return -1;
 

     av_des = av_des_alloc();
     if (!av_des)
         return AVERROR(ENOMEM);
 

     /* m_val */

     av_des_init(av_des, r_val, 192, 1);
     av_des_crypt(av_des, oc->m_val, &enc_header[48], 1, NULL, 1);

 
     /* s_val */

     av_des_init(av_des, oc->m_val, 64, 0);
     av_des_crypt(av_des, oc->s_val, NULL, 1, NULL, 0);

 
     /* sm_val */
     pos = OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size;

     av_des_init(av_des, oc->s_val, 64, 0);
     av_des_mac(av_des, oc->sm_val, &enc_header[pos], (oc->i_size >> 3));

 
     pos += oc->i_size;
 

     av_free(av_des);
 

     return memcmp(&enc_header[pos], oc->sm_val, 8) ? -1 : 0;
 }
 

 static int nprobe(AVFormatContext *s, uint8_t *enc_header, unsigned size,

                   const uint8_t *n_val)

 {
     OMAContext *oc = s->priv_data;

     uint64_t pos;
     uint32_t taglen, datalen;

     struct AVDES *av_des;

     if (!enc_header || !n_val ||
         size < OMA_ENC_HEADER_SIZE + oc->k_size + 4)

         return -1;
 
     pos = OMA_ENC_HEADER_SIZE + oc->k_size;
     if (!memcmp(&enc_header[pos], "EKB ", 4))
         pos += 32;
 

     if (size < pos + 44)
         return -1;
 

     if (AV_RB32(&enc_header[pos]) != oc->rid)
         av_log(s, AV_LOG_DEBUG, "Mismatching RID\n");
 

     taglen  = AV_RB32(&enc_header[pos + 32]);
     datalen = AV_RB32(&enc_header[pos + 36]) >> 4;

     pos += 44LL + taglen;

     if (pos + (((uint64_t)datalen) << 4) > size)

         return -1;
 

     av_des = av_des_alloc();
     if (!av_des)
         return AVERROR(ENOMEM);
 
     av_des_init(av_des, n_val, 192, 1);

     while (datalen-- > 0) {

         av_des_crypt(av_des, oc->r_val, &enc_header[pos], 2, NULL, 1);

         kset(s, oc->r_val, NULL, 16);
         if (!rprobe(s, enc_header, size, oc->r_val)) {

             av_free(av_des);

             return 0;

         }

         pos += 16;
     }
 

     av_free(av_des);

     return -1;
 }
 
 static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header)
 {
     OMAContext *oc = s->priv_data;
     ID3v2ExtraMetaGEOB *geob = NULL;
     uint8_t *gdata;
 
     oc->encrypted = 1;
     av_log(s, AV_LOG_INFO, "File is encrypted\n");
 
     /* find GEOB metadata */
     while (em) {
         if (!strcmp(em->tag, "GEOB") &&
             (geob = em->data) &&

             (!strcmp(geob->description, "OMG_LSI") ||
              !strcmp(geob->description, "OMG_BKLSI"))) {

             break;
         }
         em = em->next;
     }
     if (!em) {
         av_log(s, AV_LOG_ERROR, "No encryption header found\n");

         return AVERROR_INVALIDDATA;

     }
 
     if (geob->datasize < 64) {

         av_log(s, AV_LOG_ERROR,

                "Invalid GEOB data size: %"PRIu32"\n", geob->datasize);

         return AVERROR_INVALIDDATA;

     }
 
     gdata = geob->data;
 
     if (AV_RB16(gdata) != 1)
         av_log(s, AV_LOG_WARNING, "Unknown version in encryption header\n");
 
     oc->k_size = AV_RB16(&gdata[2]);
     oc->e_size = AV_RB16(&gdata[4]);
     oc->i_size = AV_RB16(&gdata[6]);
     oc->s_size = AV_RB16(&gdata[8]);
 
     if (memcmp(&gdata[OMA_ENC_HEADER_SIZE], "KEYRING     ", 12)) {
         av_log(s, AV_LOG_ERROR, "Invalid encryption header\n");

         return AVERROR_INVALIDDATA;

     }

     if (OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size + 8 > geob->datasize ||
         OMA_ENC_HEADER_SIZE + 48 > geob->datasize) {

         av_log(s, AV_LOG_ERROR, "Too little GEOB data\n");
         return AVERROR_INVALIDDATA;
     }

     oc->rid = AV_RB32(&gdata[OMA_ENC_HEADER_SIZE + 28]);

     av_log(s, AV_LOG_DEBUG, "RID: %.8"PRIx32"\n", oc->rid);

 
     memcpy(oc->iv, &header[0x58], 8);
     hex_log(s, AV_LOG_DEBUG, "IV", oc->iv, 8);
 

     hex_log(s, AV_LOG_DEBUG, "CBC-MAC",
             &gdata[OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size],
             8);

 
     if (s->keylen > 0) {
         kset(s, s->key, s->key, s->keylen);
     }
     if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) ||

         rprobe(s, gdata, geob->datasize, oc->r_val) < 0 &&

         nprobe(s, gdata, geob->datasize, oc->n_val) < 0) {

         int i;

         for (i = 0; i < FF_ARRAY_ELEMS(leaf_table); i += 2) {

             uint8_t buf[16];

             AV_WL64(buf,     leaf_table[i]);
             AV_WL64(&buf[8], leaf_table[i + 1]);

             kset(s, buf, buf, 16);

             if (!rprobe(s, gdata, geob->datasize, oc->r_val) ||

                 !nprobe(s, gdata, geob->datasize, oc->n_val))

                 break;
         }

         if (i >= FF_ARRAY_ELEMS(leaf_table)) {

             av_log(s, AV_LOG_ERROR, "Invalid key\n");

             return AVERROR_INVALIDDATA;

         }
     }
 

     oc->av_des = av_des_alloc();
     if (!oc->av_des)
         return AVERROR(ENOMEM);
 

     /* e_val */

     av_des_init(oc->av_des, oc->m_val, 64, 0);
     av_des_crypt(oc->av_des, oc->e_val,

                  &gdata[OMA_ENC_HEADER_SIZE + 40], 1, NULL, 0);

     hex_log(s, AV_LOG_DEBUG, "EK", oc->e_val, 8);
 
     /* init e_val */

     av_des_init(oc->av_des, oc->e_val, 64, 1);

 
     return 0;
 }

 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     OMAContext *oc  = s->priv_data;
     AVStream *st    = s->streams[0];
     int packet_size = st->codecpar->block_align;
     int byte_rate   = st->codecpar->bit_rate >> 3;
     int64_t pos     = avio_tell(s->pb);
     int ret         = av_get_packet(s->pb, pkt, packet_size);
 
     if (ret < packet_size)
         pkt->flags |= AV_PKT_FLAG_CORRUPT;
 
     if (ret < 0)
         return ret;
     if (!ret)
         return AVERROR_EOF;
 
     pkt->stream_index = 0;
 
     if (pos >= oc->content_start && byte_rate > 0) {
         pkt->pts =
         pkt->dts = av_rescale(pos - oc->content_start, st->time_base.den,
                               byte_rate * (int64_t)st->time_base.num);
     }
 
     if (oc->encrypted) {
         /* previous unencrypted block saved in IV for
          * the next packet (CBC mode) */
         if (ret == packet_size)
             av_des_crypt(oc->av_des, pkt->data, pkt->data,
                          (packet_size >> 3), oc->iv, 1);
         else
             memset(oc->iv, 0, 8);
     }
 
     return ret;
 }
 
 static int aal_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int64_t pos = avio_tell(s->pb);

     int ret, pts;

     int packet_size;
     unsigned tag;
 
     if (avio_feof(s->pb))
         return AVERROR_EOF;
 
     tag = avio_rb24(s->pb);
     if (tag == 0)
         return AVERROR_EOF;
     else if (tag != MKBETAG(0,'B','L','K'))
         return AVERROR_INVALIDDATA;
 

     avio_skip(s->pb, 1);

     packet_size = avio_rb16(s->pb);
     avio_skip(s->pb, 2);
     pts = avio_rb32(s->pb);
     avio_skip(s->pb, 12);
     ret = av_get_packet(s->pb, pkt, packet_size);
     if (ret < packet_size)
         pkt->flags |= AV_PKT_FLAG_CORRUPT;
 
     if (ret < 0)
         return ret;
     if (!ret)
         return AVERROR_EOF;
 
     pkt->stream_index = 0;
     pkt->pos = pos;

     if (s->streams[0]->codecpar->codec_id == AV_CODEC_ID_ATRAC3AL) {
         pkt->duration = 1024;
         pkt->pts = pts * 1024LL;
     } else {
         pkt->duration = 2048;
         pkt->pts = pts * 2048LL;
     }

 
     return ret;
 }
 

 static int oma_read_header(AVFormatContext *s)

 {

     int     ret, framesize, jsflag, samplerate;

     uint32_t codec_params, channel_id;

     int16_t eid;
     uint8_t buf[EA3_HEADER_SIZE];
     uint8_t *edata;
     AVStream *st;

     ID3v2ExtraMeta *extra_meta = NULL;
     OMAContext *oc = s->priv_data;

     ff_id3v2_read(s, ID3v2_EA3_MAGIC, &extra_meta, 0);

     if ((ret = ff_id3v2_parse_chapters(s, &extra_meta)) < 0) {
         ff_id3v2_free_extra_meta(&extra_meta);
         return ret;
     }
 

     ret = avio_read(s->pb, buf, EA3_HEADER_SIZE);

     if (ret < EA3_HEADER_SIZE)
         return -1;

     if (memcmp(buf, ((const uint8_t[]){'E', 'A', '3'}), 3) ||
         buf[4] != 0 || buf[5] != EA3_HEADER_SIZE) {

         av_log(s, AV_LOG_ERROR, "Couldn't find the EA3 header !\n");

         return AVERROR_INVALIDDATA;

     }
 

     oc->content_start = avio_tell(s->pb);
 
     /* encrypted file */

     eid = AV_RB16(&buf[6]);

     if (eid != -1 && eid != -128 && decrypt_init(s, extra_meta, buf) < 0) {
         ff_id3v2_free_extra_meta(&extra_meta);

         return -1;
     }
 

     ff_id3v2_free_extra_meta(&extra_meta);
 

     codec_params = AV_RB24(&buf[33]);
 

     st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);
 

     st->start_time = 0;

     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     st->codecpar->codec_tag  = buf[32];
     st->codecpar->codec_id   = ff_codec_get_id(ff_oma_codec_tags,
                                                st->codecpar->codec_tag);

     oc->read_packet = read_packet;
 

     switch (buf[32]) {

     case OMA_CODECID_ATRAC3:
         samplerate = ff_oma_srate_tab[(codec_params >> 13) & 7] * 100;
         if (!samplerate) {
             av_log(s, AV_LOG_ERROR, "Unsupported sample rate\n");
             return AVERROR_INVALIDDATA;
         }
         if (samplerate != 44100)
             avpriv_request_sample(s, "Sample rate %d", samplerate);
 
         framesize = (codec_params & 0x3FF) * 8;
 
         /* get stereo coding mode, 1 for joint-stereo */
         jsflag = (codec_params >> 17) & 1;
 

         st->codecpar->channels    = 2;
         st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
         st->codecpar->sample_rate = samplerate;

         st->codecpar->bit_rate    = st->codecpar->sample_rate * framesize / (1024 / 8);

         /* fake the ATRAC3 extradata

          * (wav format, makes stream copy to wav work) */

         if (ff_alloc_extradata(st->codecpar, 14))

             return AVERROR(ENOMEM);
 

         edata = st->codecpar->extradata;

         AV_WL16(&edata[0],  1);             // always 1
         AV_WL32(&edata[2],  samplerate);    // samples rate
         AV_WL16(&edata[6],  jsflag);        // coding mode
         AV_WL16(&edata[8],  jsflag);        // coding mode
         AV_WL16(&edata[10], 1);             // always 1
         // AV_WL16(&edata[12], 0);          // always 0
 

         avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);

         break;
     case OMA_CODECID_ATRAC3P:

         channel_id = (codec_params >> 10) & 7;
         if (!channel_id) {
             av_log(s, AV_LOG_ERROR,

                    "Invalid ATRAC-X channel id: %"PRIu32"\n", channel_id);

             return AVERROR_INVALIDDATA;
         }

         st->codecpar->channel_layout = ff_oma_chid_to_native_layout[channel_id - 1];
         st->codecpar->channels       = ff_oma_chid_to_num_channels[channel_id - 1];

         framesize = ((codec_params & 0x3FF) * 8) + 8;
         samplerate = ff_oma_srate_tab[(codec_params >> 13) & 7] * 100;
         if (!samplerate) {
             av_log(s, AV_LOG_ERROR, "Unsupported sample rate\n");
             return AVERROR_INVALIDDATA;
         }

         st->codecpar->sample_rate = samplerate;

         st->codecpar->bit_rate    = samplerate * framesize / (2048 / 8);

         avpriv_set_pts_info(st, 64, 1, samplerate);
         break;
     case OMA_CODECID_MP3:

         st->need_parsing = AVSTREAM_PARSE_FULL_RAW;

         framesize = 1024;
         break;
     case OMA_CODECID_LPCM:
         /* PCM 44.1 kHz 16 bit stereo big-endian */

         st->codecpar->channels = 2;
         st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
         st->codecpar->sample_rate = 44100;

         framesize = 1024;
         /* bit rate = sample rate x PCM block align (= 4) x 8 */

         st->codecpar->bit_rate = st->codecpar->sample_rate * 32;
         st->codecpar->bits_per_coded_sample =
             av_get_bits_per_sample(st->codecpar->codec_id);
         avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);

         break;

     case OMA_CODECID_ATRAC3AL:
         st->codecpar->channels    = 2;
         st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
         st->codecpar->sample_rate = 44100;
         avpriv_set_pts_info(st, 64, 1, 44100);
         oc->read_packet = aal_read_packet;
         framesize = 4096;
         break;
     case OMA_CODECID_ATRAC3PAL:
         st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
         st->codecpar->channels       = 2;
         st->codecpar->sample_rate = 44100;
         avpriv_set_pts_info(st, 64, 1, 44100);
         oc->read_packet = aal_read_packet;
         framesize = 4096;
         break;

     default:
         av_log(s, AV_LOG_ERROR, "Unsupported codec %d!\n", buf[32]);

         return AVERROR(ENOSYS);

     }
 

     st->codecpar->block_align = framesize;

 
     return 0;
 }
 
 static int oma_read_packet(AVFormatContext *s, AVPacket *pkt)
 {

     OMAContext *oc  = s->priv_data;

     return oc->read_packet(s, pkt);

 }
 
 static int oma_read_probe(AVProbeData *p)
 {

     const uint8_t *buf = p->buf;

     unsigned tag_len = 0;
 

     if (p->buf_size >= ID3v2_HEADER_SIZE && ff_id3v2_match(buf, ID3v2_EA3_MAGIC))
         tag_len = ff_id3v2_tag_len(buf);

 
     /* This check cannot overflow as tag_len has at most 28 bits */
     if (p->buf_size < tag_len + 5)
         /* EA3 header comes late, might be outside of the probe buffer */

         return tag_len ? AVPROBE_SCORE_EXTENSION/2 : 0;

     buf += tag_len;
 
     if (!memcmp(buf, "EA3", 3) && !buf[4] && buf[5] == EA3_HEADER_SIZE)

         return AVPROBE_SCORE_MAX;
     else
         return 0;
 }
 

 static int oma_read_seek(struct AVFormatContext *s,
                          int stream_index, int64_t timestamp, int flags)

 {
     OMAContext *oc = s->priv_data;

     AVStream *st = s->streams[0];
     int64_t err;
 
     if (st->codecpar->codec_id == AV_CODEC_ID_ATRAC3PAL ||
         st->codecpar->codec_id == AV_CODEC_ID_ATRAC3AL)
         return -1;

     err = ff_pcm_read_seek(s, stream_index, timestamp, flags);

     if (!oc->encrypted)
         return err;
 
     /* readjust IV for CBC */
     if (err || avio_tell(s->pb) < oc->content_start)
         goto wipe;
     if ((err = avio_seek(s->pb, -8, SEEK_CUR)) < 0)
         goto wipe;
     if ((err = avio_read(s->pb, oc->iv, 8)) < 8) {
         if (err >= 0)
             err = AVERROR_EOF;
         goto wipe;

     }
 
     return 0;

 wipe:
     memset(oc->iv, 0, 8);
     return err;

 }

 static int oma_read_close(AVFormatContext *s)
 {
     OMAContext *oc = s->priv_data;
     av_free(oc->av_des);
     return 0;
 }
 

 AVInputFormat ff_oma_demuxer = {

     .name           = "oma",
     .long_name      = NULL_IF_CONFIG_SMALL("Sony OpenMG audio"),

     .priv_data_size = sizeof(OMAContext),

     .read_probe     = oma_read_probe,
     .read_header    = oma_read_header,
     .read_packet    = oma_read_packet,

     .read_seek      = oma_read_seek,

     .read_close     = oma_read_close,

     .flags          = AVFMT_GENERIC_INDEX,
     .extensions     = "oma,omg,aa3",

     .codec_tag      = (const AVCodecTag* const []){ff_oma_codec_tags, 0},

 };