Recognize the eof packet also in the udp receiver.
[paraslash.git] / vss.c
diff --git a/vss.c b/vss.c
index e0c0b584dbe4819f392d02c1d33076e4751af492..481c0b68e19fb342489736c3f2c36d6e92eb9b1c 100644 (file)
--- a/vss.c
+++ b/vss.c
 /*
- * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file vss.c the virtual streaming system
+/** \file vss.c The virtual streaming system.
  *
  * This contains the audio streaming code of para_server which is independent
  * of the current audio format, audio file selector and of the activated
  * senders.
  */
 
+#include <dirent.h>
+
 #include "para.h"
+#include "error.h"
+#include "portable_io.h"
+#include "fec.h"
+#include "string.h"
 #include "afh.h"
+#include "afs.h"
 #include "server.h"
-#include <sys/mman.h> /* mmap */
-#include <sys/time.h> /* gettimeofday */
+#include "net.h"
 #include "server.cmdline.h"
-#include "afs_common.h"
+#include "list.h"
 #include "vss.h"
 #include "send.h"
-#include "error.h"
-#include "string.h"
+#include "ipc.h"
 #include "fd.h"
-
-extern const char *status_item_list[];
-
-static struct timeval announce_tv;
-static struct timeval data_send_barrier;
-static struct timeval eof_barrier;
-static struct timeval autoplay_barrier;
+#include "sched.h"
 
 extern struct misc_meta_data *mmd;
-extern struct audio_file_selector selectors[];
-extern struct sender senders[];
-
-static int audio_file;
-static char *map;
 
-#if 1
-       void mp3_init(struct audio_format_handler *);
-#endif
+extern void dccp_send_init(struct sender *);
+extern void http_send_init(struct sender *);
+extern void udp_send_init(struct sender *);
 
-#ifdef HAVE_OGGVORBIS
-       void ogg_init(struct audio_format_handler *);
-#endif
-#ifdef HAVE_FAAD
-       void aac_afh_init(struct audio_format_handler *);
-#endif
-
-/**
- * the list of supported  audio formats
- */
-static struct audio_format_handler afl[] = {
-#if 1
+/** The list of supported senders. */
+struct sender senders[] = {
        {
-               .name = "mp3",
-               .init = mp3_init,
+               .name = "http",
+               .init = http_send_init,
        },
-#endif
-#ifdef HAVE_OGGVORBIS
        {
-               .name = "ogg",
-               .init = ogg_init,
+               .name = "dccp",
+               .init = dccp_send_init,
        },
-#endif
-#ifdef HAVE_FAAD
        {
-               .name = "aac",
-               .init = aac_afh_init,
+               .name = "udp",
+               .init = udp_send_init,
        },
-#endif
        {
                .name = NULL,
        }
 };
 
-/** iterate over each supported audio format */
-#define FOR_EACH_AUDIO_FORMAT(i) for (i = 0; afl[i].name; i++)
+/** The possible states of the afs socket. */
+enum afs_socket_status {
+       /** Socket is inactive. */
+       AFS_SOCKET_READY,
+       /** Socket fd was included in the write fd set for select(). */
+       AFS_SOCKET_CHECK_FOR_WRITE,
+       /** vss wrote a request to the socket and waits for reply from afs. */
+       AFS_SOCKET_AFD_PENDING
+};
 
+/** The task structure for the virtual streaming system. */
+struct vss_task {
+       /** Copied from the -announce_time command line option. */
+       struct timeval announce_tv;
+       /** End of the announcing interval. */
+       struct timeval data_send_barrier;
+       /** End of the EOF interval. */
+       struct timeval eof_barrier;
+       /** Only used if --autoplay_delay was given. */
+       struct timeval autoplay_barrier;
+       /** Used for afs-server communication. */
+       int afs_socket;
+       /** The current state of \a afs_socket. */
+       enum afs_socket_status afsss;
+       /** The memory mapped audio file. */
+       char *map;
+       /** Used by the scheduler. */
+       struct task task;
+       /** Pointer to the header of the mapped audio file. */
+       const char *header_buf;
+       /** Length of the audio file header. */
+       size_t header_len;
+};
 
+/**
+ * The list of currently connected fec clients.
+ *
+ * Senders may use \ref vss_add_fec_client() to add entries to the list.
+ */
+static struct list_head fec_client_list;
 
 /**
- * check if vss status flag \a P (playing) is set
+ * Describes one slice of a FEC group.
  *
- * \return greater than zero if playing, zero otherwise.
+ * FEC slices directly correspond to the data packages sent by the paraslash
+ * senders that use FEC. Each slice is identified by its group number and its
+ * number within the group. All slices have the same size, but the last slice
+ * of the group may not be filled entirely.
+ */
+struct fec_slice {
+       /** The slice number within the FEC group. */
+       uint8_t num;
+       /** The number of used bytes in this slice. */
+       uint16_t bytes;
+};
+
+/**
+ * Data associated with one FEC group.
  *
+ * A FEC group consists of a fixed number of slices and this number is given by
+ * the \a slices_per_group parameter of struct \ref fec_client_parms. Each FEC
+ * group contains a number of chunks of the current audio file.
  */
-unsigned int vss_playing(void)
+struct fec_group {
+       /** The number of the FEC group. */
+       uint32_t num;
+       /** Number of bytes in this group. */
+       uint32_t bytes;
+       /** The first chunk of the current audio file belonging to the group. */
+       uint32_t first_chunk;
+       /** The number of chunks contained in this group. */
+       uint32_t num_chunks;
+       /** The time needed to play all chunks of the group. */
+       struct timeval duration;
+       /** When the first chunk was sent. */
+       struct timeval start;
+       /** \a The group duration divided by \a slices_per_group. */
+       struct timeval slice_duration;
+};
+
+/**
+ * Describes one connected FEC client.
+ */
+struct fec_client {
+       /** Parameters requested by the client. */
+       struct fec_client_parms *fcp;
+       /** Used by the core FEC code. */
+       struct fec_parms *parms;
+       /** The position of this client in the fec client list. */
+       struct list_head node;
+       /** When the first slice for this client was sent. */
+       struct timeval stream_start;
+       /** The first chunk sent to this FEC client. */
+       int first_stream_chunk;
+       /** Describes the current group. */
+       struct fec_group group;
+       /** Describes the current slice. */
+       struct fec_slice slice;
+       /** The data to be FEC-encoded (point to a region within the mapped audio file). */
+       const unsigned char **src_data;
+       /** Used for the last source pointer of the last group. */
+       unsigned char *extra_src_buf;
+       /** The size of the buffer for the extra source pointer. */
+       size_t extra_src_buf_size;
+       /** Contains FEC-encoded data. */
+       unsigned char *enc_buf;
+       /** Size of \a enc_buf. */
+       size_t enc_buf_size;
+};
+
+/**
+ * Get the chunk time of the current audio file.
+ *
+ * \return A pointer to a struct containing the chunk time, or NULL,
+ * if currently no audio file is selected.
+ */
+struct timeval *vss_chunk_time(void)
 {
-       return mmd->new_vss_status_flags & VSS_PLAYING;
+       if (mmd->afd.afhi.chunk_tv.tv_sec == 0 &&
+                       mmd->afd.afhi.chunk_tv.tv_usec == 0)
+               return NULL;
+       return &mmd->afd.afhi.chunk_tv;
 }
 
 /**
- * check if \a N (next) status flag is set
- *
- * \return greater than zero if set, zero if not.
+ * Write a fec header to a buffer.
  *
+ * \param buf The buffer to write to.
+ * \param h The fec header to write.
  */
-unsigned int vss_next(void)
+static void write_fec_header(struct fec_client *fc)
 {
-       return mmd->new_vss_status_flags & VSS_NEXT;
+       char *buf = (char *)fc->enc_buf;
+
+       write_u32(buf, FEC_MAGIC);
+
+       write_u8(buf + 4, fc->fcp->slices_per_group);
+       write_u8(buf + 5, fc->fcp->data_slices_per_group);
+       write_u32(buf + 6, (uint32_t)0); /* audio header len */
+
+       write_u32(buf + 10, fc->group.num);
+       write_u32(buf + 14, fc->group.bytes);
+
+       write_u8(buf + 18, fc->slice.num);
+       write_u16(buf + 20, fc->slice.bytes);
+       memset(buf + 22, 0, 11);
+}
+
+static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+       uint32_t max_group_size, last_payload_size;
+       int i, k = fc->fcp->data_slices_per_group;
+       size_t len;
+       const char *start_buf;
+       struct timeval tmp, *chunk_tv = vss_chunk_time();
+
+       assert(chunk_tv);
+       if (fc->first_stream_chunk < 0) {
+               fc->stream_start = *now;
+               fc->first_stream_chunk = mmd->current_chunk;
+               fc->group.first_chunk = mmd->current_chunk;
+               fc->group.num = 0;
+       } else {
+               fc->group.first_chunk += fc->group.num_chunks;
+               fc->group.num++;
+       }
+       if (fc->group.first_chunk >= mmd->afd.afhi.chunks_total)
+               return 0;
+       max_group_size = (fc->fcp->max_slice_bytes - FEC_HEADER_SIZE) * k;
+       afh_get_chunk(fc->group.first_chunk, &mmd->afd.afhi, vsst->map,
+               &start_buf, &len);
+       for (i = fc->group.first_chunk, fc->group.bytes = 0;
+                       i < mmd->afd.afhi.chunks_total; i++) {
+               const char *buf;
+
+               afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len);
+               if (fc->group.bytes + len > max_group_size)
+                       break;
+               fc->group.bytes += len;
+       }
+       fc->group.num_chunks = i - fc->group.first_chunk;
+       fc->slice.num = 0;
+       fc->slice.bytes = ROUND_UP(fc->group.bytes, k) / k;
+
+       /* The last slice will not be fully used */
+       last_payload_size = fc->group.bytes % fc->slice.bytes;
+       if (!last_payload_size)
+               last_payload_size = fc->slice.bytes;
+
+       tv_scale(fc->group.first_chunk - fc->first_stream_chunk, chunk_tv,
+               &tmp);
+       tv_add(&fc->stream_start, &tmp, &fc->group.start);
+       if (fc->group.num) /* quick hack to avoid buffer underruns */
+               fc->group.start.tv_sec--;
+       tv_scale(fc->group.num_chunks, chunk_tv, &fc->group.duration);
+       tv_divide(fc->fcp->slices_per_group, &fc->group.duration,
+               &fc->group.slice_duration);
+
+       for (i = 0; i < k; i++)
+               fc->src_data[i] = (const unsigned char *)start_buf
+                       + i * fc->slice.bytes;
+
+       if (start_buf + k * fc->slice.bytes > vsst->map + mmd->size) {
+               /* can not use last slice as it goes beyond the map */
+               if (fc->extra_src_buf_size < fc->slice.bytes) {
+                       fc->extra_src_buf = para_realloc(fc->extra_src_buf, fc->slice.bytes);
+                       fc->extra_src_buf_size = fc->slice.bytes;
+               }
+               memcpy(fc->extra_src_buf, start_buf + (k - 1) * fc->slice.bytes,
+                       last_payload_size);
+               memset(fc->extra_src_buf + last_payload_size, 0,
+                       fc->slice.bytes - last_payload_size);
+               fc->src_data[k - 1] = fc->extra_src_buf;
+       }
+       if (fc->enc_buf_size < fc->slice.bytes + FEC_HEADER_SIZE) {
+               fc->enc_buf_size = fc->slice.bytes + FEC_HEADER_SIZE;
+               fc->enc_buf = para_realloc(fc->enc_buf, fc->enc_buf_size);
+       }
+       PARA_INFO_LOG("FEC group %d: %d chunks (%d - %d), duration: %lums\n",
+               fc->group.num, fc->group.num_chunks, fc->group.first_chunk,
+               fc->group.first_chunk + fc->group.num_chunks - 1,
+               tv2ms(&fc->group.duration));
+       return 1;
+}
+
+static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+       if (fc->first_stream_chunk < 0 || fc->slice.num
+                       == fc->fcp->slices_per_group) {
+               if (!setup_next_fec_group(fc, vsst))
+                       return 0;
+       }
+       write_fec_header(fc);
+       fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
+               fc->slice.num, fc->slice.bytes);
+       return 1;
 }
 
 /**
- * check if a reposition request is pending
+ * Return a buffer that marks the end of the stream.
  *
- * \return greater than zero if true, zero otherwise.
+ * \param buf Result pointer.
+ * \return The length of the eof buffer.
  *
+ * This is used for (multicast) udp streaming where closing the socket on the
+ * sender might not give rise to an eof condition at the peer.
  */
-unsigned int vss_repos(void)
+size_t vss_get_fec_eof_packet(const char **buf)
 {
-       return mmd->new_vss_status_flags & VSS_REPOS;
+       static const char fec_eof_packet[FEC_HEADER_SIZE] = FEC_EOF_PACKET;
+       *buf = fec_eof_packet;
+       return FEC_HEADER_SIZE;
 }
 
 /**
- * check if the vss is currently paused
+ * Add one entry to the list of active fec clients.
  *
- * \return greater than zero if paused, zero otherwise.
+ * \param fcp Describes the fec parameters to be used for this client.
+ * \param result An opaque pointer that must be used by remove the client later.
  *
+ * \return Standard.
  */
-unsigned int vss_paused(void)
+int vss_add_fec_client(struct fec_client_parms *fcp, struct fec_client **result)
 {
-       return !(mmd->new_vss_status_flags & VSS_NEXT)
-               && !(mmd->new_vss_status_flags & VSS_PLAYING);
+       int ret;
+       struct fec_client *fc;
+
+       if (fcp->max_slice_bytes < FEC_HEADER_SIZE + fcp->data_slices_per_group)
+               return -ERRNO_TO_PARA_ERROR(EINVAL);
+       fc = para_calloc(sizeof(*fc));
+       fc->fcp = fcp;
+       ret = fec_new(fcp->data_slices_per_group, fcp->slices_per_group,
+               &fc->parms);
+       if (ret < 0)
+               goto err;
+       fc->first_stream_chunk = -1; /* stream not yet started */
+       fc->src_data = para_malloc(fc->fcp->slices_per_group * sizeof(char *));
+       para_list_add(&fc->node, &fec_client_list);
+       *result = fc;
+       return 1;
+err:
+       fec_free(fc->parms);
+       free(fc);
+       *result = NULL;
+       return ret;
 }
 
 /**
- * get the name of the given audio format
- * \param i the audio format number
+ * Remove one entry from the list of active fec clients.
  *
- * This returns a pointer to statically allocated memory so it
- * must not be freed by the caller.
+ * \param fc The client to be removed.
  */
-const char *audio_format_name(int i)
+void vss_del_fec_client(struct fec_client *fc)
 {
-       return i >= 0?  afl[i].name : "(none)";
+       list_del(&fc->node);
+       free(fc->src_data);
+       free(fc->enc_buf);
+       free(fc->extra_src_buf);
+       fec_free(fc->parms);
+       free(fc);
 }
 
-/**
- * initialize the virtual streaming system
+/*
+ * Compute if/when next slice is due. If it isn't due yet and \a diff is
+ * not \p Null, compute the time difference next - now, where
  *
- * Call the init functions of all supported audio format handlers and
- * initialize all supported senders.
+ *     next = stream_start + (first_group_chunk - first_stream_chunk)
+ *             * chunk_time + slice_num * slice_time
  */
-void vss_init(void)
+static int next_slice_is_due(struct fec_client *fc, struct timeval *diff)
 {
-       int i;
-       char *hn = para_hostname(), *home = para_homedir();
-       long unsigned announce_time = conf.announce_time_arg > 0?
-                       conf.announce_time_arg : 300,
-               autoplay_delay = conf.autoplay_delay_arg > 0?
-                       conf.autoplay_delay_arg : 0;
+       struct timeval tmp, next;
+       int ret;
 
-       PARA_DEBUG_LOG("supported audio formats: %s\n",
-               SUPPORTED_AUDIO_FORMATS);
-       for (i = 0; afl[i].name; i++) {
-               PARA_NOTICE_LOG("initializing %s handler\n",
-                       afl[i].name);
-               afl[i].init(&afl[i]);
-       }
-       ms2tv(announce_time, &announce_tv);
-       PARA_INFO_LOG("announce timeval: %lums\n", tv2ms(&announce_tv));
-       for (i = 0; senders[i].name; i++) {
-               PARA_NOTICE_LOG("initializing %s sender\n", senders[i].name);
-               senders[i].init(&senders[i]);
-       }
-       free(hn);
-       free(home);
-       if (conf.autoplay_given) {
-               struct timeval now, tmp;
-               mmd->vss_status_flags |= VSS_PLAYING;
-               mmd->new_vss_status_flags |= VSS_PLAYING;
-               gettimeofday(&now, NULL);
-               ms2tv(autoplay_delay, &tmp);
-               tv_add(&now, &tmp, &autoplay_barrier);
-       }
+       if (fc->first_stream_chunk < 0)
+               return 1;
+       tv_scale(fc->slice.num, &fc->group.slice_duration, &tmp);
+       tv_add(&tmp, &fc->group.start, &next);
+       ret = tv_diff(&next, now, diff);
+       return ret < 0? 1 : 0;
 }
 
-static int get_file_info(int i)
+static void compute_slice_timeout(struct timeval *timeout)
 {
-       return  afl[i].get_file_info(map, mmd->size, &mmd->afi);
+       struct fec_client *fc;
+
+       assert(vss_playing());
+       list_for_each_entry(fc, &fec_client_list, node) {
+               struct timeval diff;
+
+               if (next_slice_is_due(fc, &diff)) {
+                       timeout->tv_sec = 0;
+                       timeout->tv_usec = 0;
+                       return;
+               }
+               /* timeout = min(timeout, diff) */
+               if (tv_diff(&diff, timeout, NULL) < 0)
+                       *timeout = diff;
+       }
 }
 
 /**
- * guess the audio format judging from filename
+ * Check if vss status flag \a P (playing) is set.
  *
- * \param name the filename
+ * \return Greater than zero if playing, zero otherwise.
  *
- * \return This function returns -1 if it has no idea what kind of audio
- * file this might be. Otherwise the (non-negative) number of the audio format
- * is returned.
  */
-int guess_audio_format(const char *name)
+unsigned int vss_playing(void)
 {
-       int i,j, len = strlen(name);
-
-       FOR_EACH_AUDIO_FORMAT(i) {
-               for (j = 0; afl[i].suffixes[j]; j++) {
-                       const char *p = afl[i].suffixes[j];
-                       int plen = strlen(p);
-                       if (len < plen + 1)
-                               continue;
-                       if (name[len - plen - 1] != '.')
-                               continue;
-                       if (strcasecmp(name + len - plen, p))
-                               continue;
-//                     PARA_DEBUG_LOG("might be %s\n", audio_format_name(i));
-                       return i;
-               }
-       }
-       return -1;
+       return mmd->new_vss_status_flags & VSS_PLAYING;
 }
 
-static int get_audio_format(int omit)
+/**
+ * Check if the \a N (next) status flag is set.
+ *
+ * \return Greater than zero if set, zero if not.
+ *
+ */
+unsigned int vss_next(void)
 {
-       int i;
-
-       FOR_EACH_AUDIO_FORMAT(i) {
-               if (i == omit)
-                       continue;
-               if (get_file_info(i) > 0)
-                       return i;
-       }
-       return -E_AUDIO_FORMAT;
+       return mmd->new_vss_status_flags & VSS_NEXT;
 }
 
-int get_audio_file_info(const char *path, char *data, size_t size,
-               struct audio_format_info *afhi)
+/**
+ * Check if a reposition request is pending.
+ *
+ * \return Greater than zero if true, zero otherwise.
+ *
+ */
+unsigned int vss_repos(void)
 {
-       int ret, i, format = guess_audio_format(path);
-       if (format >= 0) {
-               ret = afl[format].get_file_info(data, size, afhi);
-               if (ret >= 0)
-                       return ret;
-       }
-       FOR_EACH_AUDIO_FORMAT(i) {
-               if (i == format) /* we already tried this one to no avail */
-                       continue;
-               ret = afl[i].get_file_info(data, size, afhi);
-               if (ret >= 0)
-                       return ret;
-       }
-       return -E_AUDIO_FORMAT;
-
+       return mmd->new_vss_status_flags & VSS_REPOS;
 }
 
-/*
- * upddate shared mem
+/**
+ * Check if the vss is currently paused.
+ *
+ * \return Greater than zero if paused, zero otherwise.
+ *
  */
-static int update_mmd(void)
+unsigned int vss_paused(void)
 {
-       int i;
-
-       i = guess_audio_format(mmd->filename);
-       if (i < 0 || get_file_info(i) < 0)
-               i = get_audio_format(i);
-       if (i < 0)
-               return i;
-       mmd->audio_format = i;
-       mmd->chunks_sent = 0;
-       mmd->current_chunk = 0;
-       mmd->offset = 0;
-       mmd->events++;
-       return 1;
+       return !(mmd->new_vss_status_flags & VSS_NEXT)
+               && !(mmd->new_vss_status_flags & VSS_PLAYING);
 }
 
-static void vss_get_audio_file(void)
+/**
+ * Check if the vss is currently stopped.
+ *
+ * \return Greater than zero if paused, zero otherwise.
+ *
+ */
+unsigned int vss_stopped(void)
 {
-       char **sl = selectors[mmd->selector_num].get_audio_file_list(10);
-       int i;
-       struct stat file_status;
-
-       if (!sl)
-               goto err_out;
-       for (i = 0; sl[i]; i++) {
-               struct timeval now;
-               PARA_INFO_LOG("trying %s\n", sl[i]);
-               if (strlen(sl[i]) >= _POSIX_PATH_MAX)
-                       continue;
-               audio_file = open(sl[i], O_RDONLY);
-               if (audio_file < 0)
-                       continue;
-               if (fstat(audio_file, &file_status) == -1 ||
-                               !file_status.st_size) {
-                       close(audio_file);
-                       continue;
-               }
-               mmd->size = file_status.st_size;
-               mmd->mtime = file_status.st_mtime;
-               map = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE,
-                       audio_file, 0);
-               strcpy(mmd->filename, sl[i]);
-               mmd->afi.header_len = 0; /* default: no header */
-               if (update_mmd() < 0) { /* invalid file */
-                       close(audio_file);
-                       munmap(map, mmd->size);
-                       map = NULL;
-                       continue;
-               }
-               mmd->num_played++;
-               if (selectors[mmd->selector_num].update_audio_file)
-                       selectors[mmd->selector_num].update_audio_file(sl[i]);
-               PARA_NOTICE_LOG("next audio file: %s\n", mmd->filename);
-               mmd->new_vss_status_flags &= (~VSS_NEXT);
-               gettimeofday(&now, NULL);
-               tv_add(&now, &announce_tv, &data_send_barrier);
-               goto free;
-       }
-err_out:
-       PARA_ERROR_LOG("%s", "no valid files found\n");
-       mmd->new_vss_status_flags = VSS_NEXT;
-free:
-       if (sl) {
-               for (i = 0; sl[i]; i++)
-                       free(sl[i]);
-               free(sl);
-       }
+       return (mmd->new_vss_status_flags & VSS_NEXT)
+               && !(mmd->new_vss_status_flags & VSS_PLAYING);
 }
 
-static int chk_barrier(const char *bname, const struct timeval *now,
-               const struct timeval *barrier, struct timeval *diff,
-               int print_log)
+static int chk_barrier(const char *bname, const struct timeval *barrier,
+               struct timeval *diff, int print_log)
 {
        long ms;
 
@@ -333,107 +466,75 @@ static int chk_barrier(const char *bname, const struct timeval *now,
        return -1;
 }
 
-static void vss_next_chunk_time(struct timeval *due)
-{
-       struct timeval tmp;
-
-       tv_scale(mmd->chunks_sent, &mmd->afi.chunk_tv, &tmp);
-       tv_add(&tmp, &mmd->stream_start, due);
-}
-
 /*
  * != NULL: timeout for next chunk
  * NULL: nothing to do
  */
-static struct timeval *vss_compute_timeout(void)
+static struct timeval *vss_compute_timeout(struct vss_task *vsst)
 {
        static struct timeval the_timeout;
-       struct timeval now, next_chunk;
+       struct timeval next_chunk;
 
-       if (vss_next() && mmd->audio_format >= 0) {
+       if (vss_next() && vsst->map) {
                /* only sleep a bit, nec*/
                the_timeout.tv_sec = 0;
                the_timeout.tv_usec = 100;
                return &the_timeout;
        }
-       gettimeofday(&now, NULL);
-       if (chk_barrier("autoplay_delay", &now, &autoplay_barrier,
+       if (chk_barrier("autoplay_delay", &vsst->autoplay_barrier,
                        &the_timeout, 1) < 0)
                return &the_timeout;
-       if (chk_barrier("eof", &now, &eof_barrier, &the_timeout, 1) < 0)
+       if (chk_barrier("eof", &vsst->eof_barrier, &the_timeout, 1) < 0)
                return &the_timeout;
-       if (chk_barrier("data send", &now, &data_send_barrier,
+       if (chk_barrier("data send", &vsst->data_send_barrier,
                        &the_timeout, 1) < 0)
                return &the_timeout;
-       if (mmd->audio_format < 0 || !vss_playing() || !map)
+       if (!vss_playing() || !vsst->map)
                return NULL;
-       vss_next_chunk_time(&next_chunk);
-       if (chk_barrier(afl[mmd->audio_format].name, &now, &next_chunk,
-                       &the_timeout, 0) < 0)
+       compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
+               &mmd->stream_start, &next_chunk);
+       if (chk_barrier("chunk", &next_chunk, &the_timeout, 0) >= 0) {
+               /* chunk is due or bof */
+               the_timeout.tv_sec = 0;
+               the_timeout.tv_usec = 0;
                return &the_timeout;
-       /* chunk is due or bof */
-       the_timeout.tv_sec = 0;
-       the_timeout.tv_usec = 0;
+       }
+       /* compute min of current timeout and next slice time */
+       compute_slice_timeout(&the_timeout);
        return &the_timeout;
 }
 
-static void vss_eof(void)
+static void vss_eof(struct vss_task *vsst)
 {
-       struct timeval now;
-       int i;
-       char *tmp;
 
-       if (!map) {
-               for (i = 0; senders[i].name; i++)
-                       senders[i].shutdown_clients();
+       mmd->stream_start = *now;
+       if (!vsst->map)
                return;
-       }
-       gettimeofday(&now, NULL);
-       tv_add(&mmd->afi.eof_tv, &now, &eof_barrier);
-       munmap(map, mmd->size);
-       map = NULL;
-       close(audio_file);
-       mmd->audio_format = -1;
+       if (mmd->new_vss_status_flags & VSS_NOMORE)
+               mmd->new_vss_status_flags = VSS_NEXT;
+       tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+       para_munmap(vsst->map, mmd->size);
+       vsst->map = NULL;
        mmd->chunks_sent = 0;
        mmd->offset = 0;
-       mmd->afi.seconds_total = 0;
-       free(mmd->afi.chunk_table);
-       mmd->afi.chunk_table = NULL;
-       tmp  = make_message("%s:\n%s:\n%s:\n", status_item_list[SI_AUDIO_INFO1],
-               status_item_list[SI_AUDIO_INFO2], status_item_list[SI_AUDIO_INFO3]);
-       strcpy(mmd->afi.info_string, tmp);
-       free(tmp);
-       tmp  = make_message("%s:\n%s:\n%s:\n", status_item_list[SI_DBINFO1],
-               status_item_list[SI_DBINFO2], status_item_list[SI_DBINFO3]);
-       strcpy(mmd->selector_info, tmp);
-       free(tmp);
-       mmd->filename[0] = '\0';
+       mmd->afd.afhi.seconds_total = 0;
+       mmd->afd.afhi.chunk_tv.tv_sec = 0;
+       mmd->afd.afhi.chunk_tv.tv_usec = 0;
+       free(mmd->afd.afhi.chunk_table);
+       mmd->afd.afhi.chunk_table = NULL;
+       free(mmd->afd.afhi.info_string);
+       mmd->afd.afhi.info_string = make_message("%s:\n%s:\n%s:\n", status_item_list[SI_AUDIO_FILE_INFO],
+               status_item_list[SI_TAGINFO1], status_item_list[SI_TAGINFO2]);
+       make_empty_status_items(mmd->afd.verbose_ls_output);
+       mmd->mtime = 0;
        mmd->size = 0;
        mmd->events++;
 }
 
 /**
- * get the header and of the current audio file
+ * Get the list of all supported audio formats.
  *
- * \param header_len the length of the header is stored here
- *
- * \return a pointer to a buffer containing the header, or NULL, if no audio
- * file is selected or if the current audio format does not need special header
- * treamtment.
- *
- */
-char *vss_get_header(size_t *header_len)
-{
-       if (mmd->audio_format < 0 || !map || !mmd->afi.header_len)
-               return NULL;
-       *header_len = mmd->afi.header_len;
-       return map + mmd->afi.header_offset;
-}
-
-/**
- * get the list of all supported audio formats
- *
- * \return a space separated list of all supported audio formats
+ * \return Aa space separated list of all supported audio formats
  * It is not allocated at runtime, i.e. there is no need to free
  * the returned string in the caller.
  */
@@ -442,157 +543,314 @@ const char *supported_audio_formats(void)
        return SUPPORTED_AUDIO_FORMATS;
 }
 
-/**
- * get the chunk time of the current audio file
- *
- * \return a pointer to a struct containing the chunk time, or NULL,
- * if currently no audio file is selected.
- */
-struct timeval *vss_chunk_time(void)
+static int need_to_request_new_audio_file(struct vss_task *vsst)
 {
-       if (mmd->audio_format < 0)
-               return NULL;
-       return &mmd->afi.chunk_tv;
+       struct timeval diff;
+
+       if (vsst->map) /* have audio file */
+               return 0;
+       if (!vss_playing()) /* don't need one */
+               return 0;
+       if (mmd->new_vss_status_flags & VSS_NOMORE)
+               return 0;
+       if (vsst->afsss == AFS_SOCKET_AFD_PENDING) /* already requested one */
+               return 0;
+       if (chk_barrier("autoplay_delay", &vsst->autoplay_barrier,
+                       &diff, 1) < 0)
+               return 0;
+       return 1;
 }
 
+
+
 /**
- * compute the timeout for para_server's main select-loop
+ * Compute the timeout for para_server's main select-loop.
  *
  * This function gets called from para_server to determine the timeout value
  * for its main select loop.
  *
+ * \param s Pointer to the server scheduler.
+ * \param t Pointer to the vss task structure.
+ *
  * Before the timeout is computed, the current vss status flags are evaluated
  * and acted upon by calling appropriate functions from the lower layers.
  * Possible actions include
  *
- *     - request a new file list from the current audio file selector
- *     - shutdown of all senders (stop/pause command)
- *     - reposition the stream (ff/jmp command)
- *
- * \return A pointer to a struct timeval containing the timeout for the next
- * chunk of data to be sent, or NULL if we're not sending right now.
+ *     - request a new audio file from afs,
+ *     - shutdown of all senders (stop/pause command),
+ *     - reposition the stream (ff/jmp command).
  */
-struct timeval *vss_preselect(void)
+static void vss_pre_select(struct sched *s, struct task *t)
 {
-       struct audio_format_handler *af = NULL;
-       int i, format;
-       struct timeval *ret;
-again:
-       format = mmd->audio_format;
-       if (format >= 0)
-               af = afl + format;
-       else
+       int i;
+       struct timeval *tv, diff;
+       struct vss_task *vsst = container_of(t, struct vss_task, task);
+
+       if (!vsst->map || vss_next() || vss_paused() || vss_repos()) {
+               struct fec_client *fc, *tmp;
                for (i = 0; senders[i].name; i++)
-                       senders[i].shutdown_clients();
-       if (vss_next() && af) {
-               vss_eof();
-               return vss_compute_timeout();
+                       if (senders[i].shutdown_clients)
+                               senders[i].shutdown_clients();
+               list_for_each_entry_safe(fc, tmp, &fec_client_list, node)
+                       fc->first_stream_chunk = -1;
        }
-       if (vss_paused() || vss_repos()) {
-               for (i = 0; senders[i].name; i++)
-                       senders[i].shutdown_clients();
-               if (af) {
-                       struct timeval now;
-                       gettimeofday(&now, NULL);
-                       if (!vss_paused() || mmd->chunks_sent)
-                               tv_add(&mmd->afi.eof_tv, &now, &eof_barrier);
-                       if (vss_repos())
-                               tv_add(&now, &announce_tv, &data_send_barrier);
-                       if (mmd->new_vss_status_flags & VSS_NOMORE)
-                               mmd->new_vss_status_flags = VSS_NEXT;
-               }
+       if (vss_next())
+               vss_eof(vsst);
+       else if (vss_paused()) {
+               if (mmd->chunks_sent)
+                       tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
+               mmd->chunks_sent = 0;
+       } else if (vss_repos()) {
+               tv_add(now, &vsst->announce_tv, &vsst->data_send_barrier);
+               tv_add(&mmd->afd.afhi.eof_tv, now, &vsst->eof_barrier);
                mmd->chunks_sent = 0;
-       }
-       if (vss_repos()) {
-               mmd->new_vss_status_flags &= ~(VSS_REPOS);
                mmd->current_chunk = mmd->repos_request;
+               mmd->new_vss_status_flags &= ~VSS_REPOS;
        }
-       ret = vss_compute_timeout();
-       if (!ret && !map && vss_playing() &&
-                       !(mmd->new_vss_status_flags & VSS_NOMORE)) {
-               PARA_DEBUG_LOG("%s", "ready and playing, but no audio file\n");
-               vss_get_audio_file();
-               goto again;
+       if (need_to_request_new_audio_file(vsst)) {
+               PARA_DEBUG_LOG("ready and playing, but no audio file\n");
+               para_fd_set(vsst->afs_socket, &s->wfds, &s->max_fileno);
+               vsst->afsss = AFS_SOCKET_CHECK_FOR_WRITE;
+       } else
+               para_fd_set(vsst->afs_socket, &s->rfds, &s->max_fileno);
+       for (i = 0; senders[i].name; i++) {
+               if (!senders[i].pre_select)
+                       continue;
+               senders[i].pre_select(&s->max_fileno, &s->rfds, &s->wfds);
        }
-       return ret;
+       tv = vss_compute_timeout(vsst);
+       if (tv && tv_diff(tv, &s->timeout, &diff) < 0)
+               s->timeout = *tv;
 }
 
-static void get_chunk(long unsigned chunk_num, char **buf, size_t *len)
+static int recv_afs_msg(int afs_socket, int *fd, uint32_t *code, uint32_t *data)
 {
-       size_t pos = mmd->afi.chunk_table[chunk_num];
-       *buf = map + pos;
-       *len = mmd->afi.chunk_table[chunk_num + 1] - pos;
+       char control[255], buf[8];
+       struct msghdr msg = {.msg_iov = NULL};
+       struct cmsghdr *cmsg;
+       struct iovec iov;
+       int ret = 0;
+
+       *fd = -1;
+       iov.iov_base = buf;
+       iov.iov_len = sizeof(buf);
+       msg.msg_iov = &iov;
+       msg.msg_iovlen = 1;
+       msg.msg_control = control;
+       msg.msg_controllen = sizeof(control);
+       memset(buf, 0, sizeof(buf));
+       ret = recvmsg(afs_socket, &msg, 0);
+       if (ret < 0)
+               return -ERRNO_TO_PARA_ERROR(errno);
+       if (iov.iov_len != sizeof(buf))
+               return -E_AFS_SHORT_READ;
+       *code = *(uint32_t*)buf;
+       *data =  *(uint32_t*)(buf + 4);
+       for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+               if (cmsg->cmsg_level != SOL_SOCKET
+                       || cmsg->cmsg_type != SCM_RIGHTS)
+               continue;
+               if ((cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int) != 1)
+               continue;
+               *fd = *(int *)CMSG_DATA(cmsg);
+       }
+       return 1;
 }
 
-/**
- * Get the data of the given chunk.
- *
- * \param chunk_num The number of the desired chunk.
- * \param buf Chunk data.
- * \param len Chunk length in bytes.
- *
- * \return Positive on success, negative on errors.
- */
-int vss_get_chunk(long unsigned chunk_num, char **buf, size_t *len)
+static void recv_afs_result(struct vss_task *vsst)
 {
-       if (mmd->audio_format < 0 || !map || !vss_playing())
-               return -E_CHUNK;
-       if (chunk_num >= mmd->afi.chunks_total)
-               return -E_CHUNK;
-       get_chunk(chunk_num, buf, len);
-       return 1;
+       int ret, passed_fd, shmid;
+       uint32_t afs_code = 0, afs_data = 0;
+       struct stat statbuf;
+
+       vsst->afsss = AFS_SOCKET_READY;
+       mmd->afd.afhi.chunk_table = NULL;
+       ret = recv_afs_msg(vsst->afs_socket, &passed_fd, &afs_code, &afs_data);
+       if (ret < 0)
+               goto err;
+       PARA_DEBUG_LOG("fd: %d, code: %u, shmid: %u\n", passed_fd, afs_code,
+               afs_data);
+       ret = -E_NOFD;
+       if (afs_code != NEXT_AUDIO_FILE)
+               goto err;
+       if (passed_fd < 0)
+               goto err;
+       shmid = afs_data;
+       ret = load_afd(shmid, &mmd->afd);
+       if (ret < 0)
+               goto err;
+       shm_destroy(shmid);
+       ret = fstat(passed_fd, &statbuf);
+       if (ret < 0) {
+               PARA_ERROR_LOG("fstat error:\n");
+               ret = -ERRNO_TO_PARA_ERROR(errno);
+               goto err;
+       }
+       mmd->size = statbuf.st_size;
+       mmd->mtime = statbuf.st_mtime;
+       ret = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE, passed_fd,
+               0, &vsst->map);
+       if (ret < 0)
+               goto err;
+       close(passed_fd);
+       mmd->chunks_sent = 0;
+       mmd->current_chunk = 0;
+       mmd->offset = 0;
+       mmd->events++;
+       mmd->num_played++;
+       mmd->new_vss_status_flags &= (~VSS_NEXT);
+       afh_get_header(&mmd->afd.afhi, vsst->map, &vsst->header_buf,
+               &vsst->header_len);
+       return;
+err:
+       free(mmd->afd.afhi.chunk_table);
+       if (passed_fd >= 0)
+               close(passed_fd);
+       PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+       mmd->new_vss_status_flags = VSS_NEXT;
 }
 
 /**
- * main sending function
+ * Main sending function.
  *
- * This function gets called from para_server as soon as the next chunk of
- * data should be pushed out. It first calls the read_chunk() function of
- * the current audio format handler to obtain a pointer to the data to be
- * sent out as well as its length. This information is then passed to each
- * supported sender's send() function which does the actual sending.
+ * This function gets called from vss_post_select(). It checks whether the next
+ * chunk of data should be pushed out. It obtains a pointer to the data to be
+ * sent out as well as its length from mmd->afd.afhi. This information is then
+ * passed to each supported sender's send() function as well as to the send()
+ * functions of each registered fec client.
  */
-void vss_send_chunk(void)
+static void vss_send(struct vss_task *vsst)
 {
        int i;
-       struct audio_format_handler *af;
-       struct timeval now, due;
+       struct timeval due;
+       struct fec_client *fc, *tmp_fc;
 
-       if (mmd->audio_format < 0 || !map || !vss_playing())
-               return;
-       af = &afl[mmd->audio_format];
-       gettimeofday(&now, NULL);
-       vss_next_chunk_time(&due);
-       if (tv_diff(&due, &now, NULL) > 0)
+       if (!vsst->map || !vss_playing())
                return;
-       if (chk_barrier("eof", &now, &eof_barrier, &due, 1) < 0)
+       if (chk_barrier("eof", &vsst->eof_barrier, &due, 1) < 0)
                return;
-       if (chk_barrier("data send", &now, &data_send_barrier,
+       if (chk_barrier("data send", &vsst->data_send_barrier,
                        &due, 1) < 0)
                return;
-       mmd->new_vss_status_flags &= ~VSS_REPOS;
-       if (mmd->current_chunk >= mmd->afi.chunks_total) { /* eof */
+       if (mmd->current_chunk >= mmd->afd.afhi.chunks_total) { /* eof */
                mmd->new_vss_status_flags |= VSS_NEXT;
-               return vss_eof();
+               return;
        }
-       /*
-        * We call the send function also in case of empty chunks as they
-        * might have still some data queued which can be sent in this case.
-        */
        if (!mmd->chunks_sent) {
                struct timeval tmp;
-               gettimeofday(&mmd->stream_start, NULL);
-               tv_scale(mmd->current_chunk, &mmd->afi.chunk_tv, &tmp);
+               mmd->stream_start = *now;
+               tv_scale(mmd->current_chunk, &mmd->afd.afhi.chunk_tv, &tmp);
                mmd->offset = tv2ms(&tmp);
                mmd->events++;
        }
-       for (i = 0; senders[i].name; i++) {
-               char *buf;
+       compute_chunk_time(mmd->chunks_sent, &mmd->afd.afhi.chunk_tv,
+               &mmd->stream_start, &due);
+       if (tv_diff(&due, now, NULL) <= 0) {
+               const char *buf;
                size_t len;
-               get_chunk(mmd->current_chunk, &buf, &len);
-               senders[i].send(mmd->current_chunk, mmd->chunks_sent, buf, len);
+               /*
+                * We call the send function also in case of empty chunks as
+                * they might have still some data queued which can be sent in
+                * this case.
+                */
+               afh_get_chunk(mmd->current_chunk, &mmd->afd.afhi, vsst->map,
+                       &buf, &len);
+               for (i = 0; senders[i].name; i++) {
+                       if (!senders[i].send)
+                               continue;
+                       senders[i].send(mmd->current_chunk, mmd->chunks_sent,
+                               buf, len, vsst->header_buf, vsst->header_len);
+               }
+       }
+       list_for_each_entry_safe(fc, tmp_fc, &fec_client_list, node) {
+               if (!next_slice_is_due(fc, NULL))
+                       continue;
+               if (!compute_next_fec_slice(fc, vsst))
+                       continue;
+               PARA_DEBUG_LOG("sending %d:%d (%u bytes)\n", fc->group.num,
+                       fc->slice.num, fc->slice.bytes);
+               fc->fcp->send((char *)fc->enc_buf,
+                       fc->slice.bytes + FEC_HEADER_SIZE,
+                       fc->fcp->private_data);
+               fc->slice.num++;
        }
        mmd->new_vss_status_flags |= VSS_PLAYING;
        mmd->chunks_sent++;
        mmd->current_chunk++;
 }
+
+static void vss_post_select(struct sched *s, struct task *t)
+{
+       int ret, i;
+       struct vss_task *vsst = container_of(t, struct vss_task, task);
+
+       if (mmd->sender_cmd_data.cmd_num >= 0) {
+               int num = mmd->sender_cmd_data.cmd_num,
+                       sender_num = mmd->sender_cmd_data.sender_num;
+
+               if (senders[sender_num].client_cmds[num])
+                       senders[sender_num].client_cmds[num](&mmd->sender_cmd_data);
+               mmd->sender_cmd_data.cmd_num = -1;
+       }
+       if (vsst->afsss != AFS_SOCKET_CHECK_FOR_WRITE) {
+               if (FD_ISSET(vsst->afs_socket, &s->rfds))
+                       recv_afs_result(vsst);
+       } else if (FD_ISSET(vsst->afs_socket, &s->wfds)) {
+               PARA_NOTICE_LOG("requesting new fd from afs\n");
+               ret = send_buffer(vsst->afs_socket, "new");
+               vsst->afsss = AFS_SOCKET_AFD_PENDING;
+       }
+       for (i = 0; senders[i].name; i++) {
+               if (!senders[i].post_select)
+                       continue;
+               senders[i].post_select(&s->rfds, &s->wfds);
+       }
+       if ((vss_playing() && !(mmd->vss_status_flags & VSS_PLAYING)) ||
+                       (vss_next() && vss_playing()))
+               tv_add(now, &vsst->announce_tv, &vsst->data_send_barrier);
+       vss_send(vsst);
+}
+
+/**
+ * Initialize the virtual streaming system task.
+ *
+ * \param afs_socket The fd for communication with afs.
+ *
+ * This also initializes all supported senders and starts streaming
+ * if the --autoplay command line flag was given.
+ */
+void init_vss_task(int afs_socket)
+{
+       static struct vss_task vss_task_struct, *vsst = &vss_task_struct;
+       int i;
+       char *hn = para_hostname(), *home = para_homedir();
+       long unsigned announce_time = conf.announce_time_arg > 0?
+                       conf.announce_time_arg : 300,
+               autoplay_delay = conf.autoplay_delay_arg > 0?
+                       conf.autoplay_delay_arg : 0;
+
+       vsst->afs_socket = afs_socket;
+       vsst->task.pre_select = vss_pre_select;
+       vsst->task.post_select = vss_post_select;
+       ms2tv(announce_time, &vsst->announce_tv);
+       PARA_INFO_LOG("announce timeval: %lums\n", tv2ms(&vsst->announce_tv));
+       for (i = 0; senders[i].name; i++) {
+               PARA_NOTICE_LOG("initializing %s sender\n", senders[i].name);
+               senders[i].init(&senders[i]);
+       }
+       free(hn);
+       free(home);
+       mmd->sender_cmd_data.cmd_num = -1;
+       make_empty_status_items(mmd->afd.verbose_ls_output);
+       if (conf.autoplay_given) {
+               struct timeval tmp;
+               mmd->vss_status_flags |= VSS_PLAYING;
+               mmd->new_vss_status_flags |= VSS_PLAYING;
+               ms2tv(autoplay_delay, &tmp);
+               tv_add(now, &tmp, &vsst->autoplay_barrier);
+               tv_add(&vsst->autoplay_barrier, &vsst->announce_tv,
+                       &vsst->data_send_barrier);
+       }
+       INIT_LIST_HEAD(&fec_client_list);
+       register_task(&vsst->task);
+}