/*
  * Session Announcement Protocol (RFC 2974) muxer
  * Copyright (c) 2010 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 "avformat.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/random_seed.h"
 #include "libavutil/avstring.h"
 #include "libavutil/intreadwrite.h"
 #include "internal.h"
 #include "network.h"

 #include "os_support.h"

 #include "rtpenc_chain.h"

 #include "url.h"

 
 struct SAPState {
     uint8_t    *ann;
     int         ann_size;
     URLContext *ann_fd;
     int64_t     last_time;
 };
 
 static int sap_write_close(AVFormatContext *s)
 {
     struct SAPState *sap = s->priv_data;
     int i;
 
     for (i = 0; i < s->nb_streams; i++) {
         AVFormatContext *rtpctx = s->streams[i]->priv_data;
         if (!rtpctx)
             continue;
         av_write_trailer(rtpctx);

         avio_close(rtpctx->pb);

         avformat_free_context(rtpctx);

         s->streams[i]->priv_data = NULL;
     }
 
     if (sap->last_time && sap->ann && sap->ann_fd) {
         sap->ann[0] |= 4; /* Session deletion*/

         ffurl_write(sap->ann_fd, sap->ann, sap->ann_size);

     }
 
     av_freep(&sap->ann);
     if (sap->ann_fd)

         ffurl_close(sap->ann_fd);

     ff_network_close();
     return 0;
 }
 
 static int sap_write_header(AVFormatContext *s)
 {
     struct SAPState *sap = s->priv_data;
     char host[1024], path[1024], url[1024], announce_addr[50] = "";
     char *option_list;

     int port = 9875, base_port = 5004, i, pos = 0, same_port = 0, ttl = 255;

     AVFormatContext **contexts = NULL;
     int ret = 0;
     struct sockaddr_storage localaddr;
     socklen_t addrlen = sizeof(localaddr);
     int udp_fd;
 
     if (!ff_network_init())
         return AVERROR(EIO);
 
     /* extract hostname and port */

     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &base_port,

                  path, sizeof(path), s->filename);

     if (base_port < 0)
         base_port = 5004;

 
     /* search for options */
     option_list = strrchr(path, '?');
     if (option_list) {
         char buf[50];

         if (av_find_info_tag(buf, sizeof(buf), "announce_port", option_list)) {

             port = strtol(buf, NULL, 10);

         }

         if (av_find_info_tag(buf, sizeof(buf), "same_port", option_list)) {

             same_port = strtol(buf, NULL, 10);
         }

         if (av_find_info_tag(buf, sizeof(buf), "ttl", option_list)) {

             ttl = strtol(buf, NULL, 10);
         }

         if (av_find_info_tag(buf, sizeof(buf), "announce_addr", option_list)) {

             av_strlcpy(announce_addr, buf, sizeof(announce_addr));
         }
     }
 
     if (!announce_addr[0]) {
         struct addrinfo hints, *ai = NULL;
         memset(&hints, 0, sizeof(hints));

         hints.ai_family = AF_UNSPEC;

         if (getaddrinfo(host, NULL, &hints, &ai)) {
             av_log(s, AV_LOG_ERROR, "Unable to resolve %s\n", host);
             ret = AVERROR(EIO);
             goto fail;
         }
         if (ai->ai_family == AF_INET) {
             /* Also known as sap.mcast.net */
             av_strlcpy(announce_addr, "224.2.127.254", sizeof(announce_addr));

 #if HAVE_STRUCT_SOCKADDR_IN6

         } else if (ai->ai_family == AF_INET6) {
             /* With IPv6, you can use the same destination in many different
              * multicast subnets, to choose how far you want it routed.
              * This one is intended to be routed globally. */
             av_strlcpy(announce_addr, "ff0e::2:7ffe", sizeof(announce_addr));

 #endif

         } else {
             freeaddrinfo(ai);
             av_log(s, AV_LOG_ERROR, "Host %s resolved to unsupported "
                                     "address family\n", host);
             ret = AVERROR(EIO);
             goto fail;
         }
         freeaddrinfo(ai);
     }
 
     contexts = av_mallocz(sizeof(AVFormatContext*) * s->nb_streams);
     if (!contexts) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     s->start_time_realtime = av_gettime();
     for (i = 0; i < s->nb_streams; i++) {
         URLContext *fd;
 
         ff_url_join(url, sizeof(url), "rtp", NULL, host, base_port,
                     "?ttl=%d", ttl);
         if (!same_port)
             base_port += 2;

         ret = ffurl_open(&fd, url, AVIO_FLAG_WRITE);

         if (ret) {
             ret = AVERROR(EIO);
             goto fail;
         }
         s->streams[i]->priv_data = contexts[i] =
             ff_rtp_chain_mux_open(s, s->streams[i], fd, 0);
         av_strlcpy(contexts[i]->filename, url, sizeof(contexts[i]->filename));
     }
 
     ff_url_join(url, sizeof(url), "udp", NULL, announce_addr, port,
                 "?ttl=%d&connect=1", ttl);

     ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_WRITE);

     if (ret) {
         ret = AVERROR(EIO);
         goto fail;
     }
 

     udp_fd = ffurl_get_file_handle(sap->ann_fd);

     if (getsockname(udp_fd, (struct sockaddr*) &localaddr, &addrlen)) {
         ret = AVERROR(EIO);
         goto fail;
     }

     if (localaddr.ss_family != AF_INET
 #if HAVE_STRUCT_SOCKADDR_IN6
         && localaddr.ss_family != AF_INET6
 #endif
         ) {

         av_log(s, AV_LOG_ERROR, "Unsupported protocol family\n");
         ret = AVERROR(EIO);
         goto fail;
     }
     sap->ann_size = 8192;
     sap->ann = av_mallocz(sap->ann_size);
     if (!sap->ann) {
         ret = AVERROR(EIO);
         goto fail;
     }

     sap->ann[pos] = (1 << 5);
 #if HAVE_STRUCT_SOCKADDR_IN6
     if (localaddr.ss_family == AF_INET6)
         sap->ann[pos] |= 0x10;
 #endif
     pos++;

     sap->ann[pos++] = 0; /* Authentication length */
     AV_WB16(&sap->ann[pos], av_get_random_seed());
     pos += 2;
     if (localaddr.ss_family == AF_INET) {
         memcpy(&sap->ann[pos], &((struct sockaddr_in*)&localaddr)->sin_addr,
                sizeof(struct in_addr));
         pos += sizeof(struct in_addr);

 #if HAVE_STRUCT_SOCKADDR_IN6

     } else {
         memcpy(&sap->ann[pos], &((struct sockaddr_in6*)&localaddr)->sin6_addr,
                sizeof(struct in6_addr));
         pos += sizeof(struct in6_addr);

 #endif

     }
 
     av_strlcpy(&sap->ann[pos], "application/sdp", sap->ann_size - pos);
     pos += strlen(&sap->ann[pos]) + 1;
 

     if (av_sdp_create(contexts, s->nb_streams, &sap->ann[pos],

                        sap->ann_size - pos)) {
         ret = AVERROR_INVALIDDATA;
         goto fail;
     }
     av_freep(&contexts);
     av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", &sap->ann[pos]);
     pos += strlen(&sap->ann[pos]);
     sap->ann_size = pos;
 

     if (sap->ann_size > sap->ann_fd->max_packet_size) {

         av_log(s, AV_LOG_ERROR, "Announcement too large to send in one "
                                 "packet\n");
         goto fail;
     }
 
     return 0;
 
 fail:
     av_free(contexts);
     sap_write_close(s);
     return ret;
 }
 
 static int sap_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     AVFormatContext *rtpctx;
     struct SAPState *sap = s->priv_data;
     int64_t now = av_gettime();
 
     if (!sap->last_time || now - sap->last_time > 5000000) {

         int ret = ffurl_write(sap->ann_fd, sap->ann, sap->ann_size);

         /* Don't abort even if we get "Destination unreachable" */

         if (ret < 0 && ret != AVERROR(ECONNREFUSED))

             return ret;
         sap->last_time = now;
     }
     rtpctx = s->streams[pkt->stream_index]->priv_data;
     return ff_write_chained(rtpctx, 0, pkt, s);
 }
 

 AVOutputFormat ff_sap_muxer = {

     "sap",
     NULL_IF_CONFIG_SMALL("SAP output format"),
     NULL,
     NULL,
     sizeof(struct SAPState),
     CODEC_ID_AAC,
     CODEC_ID_MPEG4,
     sap_write_header,
     sap_write_packet,
     sap_write_close,
     .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER,
 };