/*
  * SRTP network protocol
  * Copyright (c) 2012 Martin Storsjo
  *

  * 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
  */
 
 #include "libavutil/opt.h"
 #include "avformat.h"
 #include "avio_internal.h"
 #include "url.h"
 
 #include "internal.h"

 #include "rtpdec.h"

 #include "srtp.h"
 
 typedef struct SRTPProtoContext {
     const AVClass *class;
     URLContext *rtp_hd;
     const char *out_suite, *out_params;
     const char *in_suite, *in_params;
     struct SRTPContext srtp_out, srtp_in;

     uint8_t encryptbuf[RTP_MAX_PACKET_LENGTH];

 } SRTPProtoContext;
 
 #define D AV_OPT_FLAG_DECODING_PARAM
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "srtp_out_suite", "", offsetof(SRTPProtoContext, out_suite), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { "srtp_out_params", "", offsetof(SRTPProtoContext, out_params), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { "srtp_in_suite", "", offsetof(SRTPProtoContext, in_suite), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { "srtp_in_params", "", offsetof(SRTPProtoContext, in_params), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { NULL }
 };
 
 static const AVClass srtp_context_class = {
     .class_name     = "srtp",
     .item_name      = av_default_item_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,
 };
 
 static int srtp_close(URLContext *h)
 {
     SRTPProtoContext *s = h->priv_data;
     ff_srtp_free(&s->srtp_out);
     ff_srtp_free(&s->srtp_in);
     ffurl_close(s->rtp_hd);
     s->rtp_hd = NULL;
     return 0;
 }
 
 static int srtp_open(URLContext *h, const char *uri, int flags)
 {
     SRTPProtoContext *s = h->priv_data;
     char hostname[256], buf[1024], path[1024];
     int rtp_port, ret;
 
     if (s->out_suite && s->out_params)
         if ((ret = ff_srtp_set_crypto(&s->srtp_out, s->out_suite, s->out_params)) < 0)
             goto fail;
     if (s->in_suite && s->in_params)
         if ((ret = ff_srtp_set_crypto(&s->srtp_in, s->in_suite, s->in_params)) < 0)
             goto fail;
 
     av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,
                  path, sizeof(path), uri);
     ff_url_join(buf, sizeof(buf), "rtp", NULL, hostname, rtp_port, "%s", path);
     if ((ret = ffurl_open(&s->rtp_hd, buf, flags, &h->interrupt_callback, NULL)) < 0)
         goto fail;
 
     h->max_packet_size = FFMIN(s->rtp_hd->max_packet_size,
                                sizeof(s->encryptbuf)) - 14;
     h->is_streamed = 1;
     return 0;
 
 fail:
     srtp_close(h);
     return ret;
 }
 
 static int srtp_read(URLContext *h, uint8_t *buf, int size)
 {
     SRTPProtoContext *s = h->priv_data;
     int ret;
 start:
     ret = ffurl_read(s->rtp_hd, buf, size);
     if (ret > 0 && s->srtp_in.aes) {
         if (ff_srtp_decrypt(&s->srtp_in, buf, &ret) < 0)
             goto start;
     }
     return ret;
 }
 
 static int srtp_write(URLContext *h, const uint8_t *buf, int size)
 {
     SRTPProtoContext *s = h->priv_data;
     if (!s->srtp_out.aes)
         return ffurl_write(s->rtp_hd, buf, size);
     size = ff_srtp_encrypt(&s->srtp_out, buf, size, s->encryptbuf,
                            sizeof(s->encryptbuf));
     if (size < 0)
         return size;
     return ffurl_write(s->rtp_hd, s->encryptbuf, size);
 }
 
 static int srtp_get_file_handle(URLContext *h)
 {
     SRTPProtoContext *s = h->priv_data;
     return ffurl_get_file_handle(s->rtp_hd);
 }
 
 static int srtp_get_multi_file_handle(URLContext *h, int **handles,
                                       int *numhandles)
 {
     SRTPProtoContext *s = h->priv_data;
     return ffurl_get_multi_file_handle(s->rtp_hd, handles, numhandles);
 }
 
 URLProtocol ff_srtp_protocol = {
     .name                      = "srtp",
     .url_open                  = srtp_open,
     .url_read                  = srtp_read,
     .url_write                 = srtp_write,
     .url_close                 = srtp_close,
     .url_get_file_handle       = srtp_get_file_handle,
     .url_get_multi_file_handle = srtp_get_multi_file_handle,
     .priv_data_size            = sizeof(SRTPProtoContext),
     .priv_data_class           = &srtp_context_class,
     .flags                     = URL_PROTOCOL_FLAG_NETWORK,
 };