+extern void dccp_send_init(struct sender *);
+extern void http_send_init(struct sender *);
+extern void udp_send_init(struct sender *);
+
+/** The list of supported senders. */
+struct sender senders[] = {
+ {
+ .name = "http",
+ .init = http_send_init,
+ },
+ {
+ .name = "dccp",
+ .init = dccp_send_init,
+ },
+ {
+ .name = "udp",
+ .init = udp_send_init,
+ },
+ {
+ .name = NULL,
+ }
+};
+
+/** 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;
+ /** Time between audio file headers are sent. */
+ struct timeval header_interval;
+};
+
+/**
+ * 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;
+
+/**
+ * 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.
+ *
+ * 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_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;
+ /** When the first chunk was sent. */
+ struct timeval start;
+ /** The group duration divided by the number of slices. */
+ struct timeval slice_duration;
+ /** Group contains the audio file header that occupies that many slices. */
+ unsigned num_header_slices;
+};
+
+/**
+ * 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;
+ /** The current slice. */
+ uint8_t current_slice_num;
+ /** The data to be FEC-encoded (point to a region within the mapped audio file). */
+ const unsigned char **src_data;
+ /** Last time an audio header was sent. */
+ struct timeval next_header_time;
+ /** Used for the last source pointer of an audio file. */
+ unsigned char *extra_src_buf;
+ /** Extra slices needed to store largest chunk + header. */
+ int num_extra_slices;
+ /** Contains the FEC-encoded data. */
+ unsigned char *enc_buf;
+};
+
+/**
+ * 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)
+{
+ 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;
+}
+
+/**
+ * Write a fec header to a buffer.
+ *
+ * \param buf The buffer to write to.
+ * \param h The fec header to write.
+ */
+static void write_fec_header(struct fec_client *fc, struct vss_task *vsst)
+{
+ char *buf = (char *)fc->enc_buf;
+ struct fec_group *g = &fc->group;
+ struct fec_client_parms *p = fc->fcp;
+
+ write_u32(buf, FEC_MAGIC);
+
+ write_u8(buf + 4, p->slices_per_group + fc->num_extra_slices);
+ write_u8(buf + 5, p->data_slices_per_group + fc->num_extra_slices);
+ write_u32(buf + 6, g->num_header_slices? vsst->header_len : 0);
+
+ write_u32(buf + 10, g->num);
+ write_u32(buf + 14, g->bytes);
+
+ write_u8(buf + 18, fc->current_slice_num);
+ write_u16(buf + 20, p->max_slice_bytes - FEC_HEADER_SIZE);
+ write_u8(buf + 22, g->first_chunk? 0 : 1);
+ write_u8(buf + 23, vsst->header_len? 1 : 0);
+ memset(buf + 24, 0, 7);
+}
+
+static int need_audio_header(struct fec_client *fc, struct vss_task *vsst)
+{
+ if (!mmd->current_chunk) {
+ tv_add(now, &vsst->header_interval, &fc->next_header_time);
+ return 0;
+ }
+ if (!vsst->header_buf)
+ return 0;
+ if (!vsst->header_len)
+ return 0;
+ if (fc->group.num && tv_diff(&fc->next_header_time, now, NULL) > 0)
+ return 0;
+ tv_add(now, &vsst->header_interval, &fc->next_header_time);
+ return 1;
+}
+
+static uint8_t num_slices(long unsigned bytes, struct fec_client *fc)
+{
+ uint16_t m = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+ return (bytes + m - 1) / m;
+}
+
+static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+ int i, k, data_slices;
+ size_t len;
+ const char *buf, *start_buf;
+ struct timeval tmp, *chunk_tv = vss_chunk_time();
+ struct fec_group *g = &fc->group;
+ unsigned slice_bytes = fc->fcp->max_slice_bytes - FEC_HEADER_SIZE;
+ uint32_t max_data_size;
+
+ assert(chunk_tv);
+ k = fc->fcp->data_slices_per_group + fc->num_extra_slices;
+ if (fc->first_stream_chunk < 0) {
+ uint32_t largest = afh_get_largest_chunk_size(&mmd->afd.afhi)
+ + vsst->header_len;
+ uint8_t needed = num_slices(largest, fc), want;
+ if (needed > fc->fcp->data_slices_per_group)
+ PARA_WARNING_LOG("fec parms insufficient for this audio file\n");
+ want = PARA_MAX(needed, fc->fcp->data_slices_per_group);
+ if (want != k) {
+ int ret;
+ fec_free(fc->parms);
+ fc->src_data = para_realloc(fc->src_data, want * sizeof(char *));
+ ret = fec_new(want, want + fc->fcp->slices_per_group
+ - fc->fcp->data_slices_per_group, &fc->parms);
+ if (ret < 0)
+ return ret;
+ k = want;
+ fc->num_extra_slices = 0;
+ if (k > fc->fcp->data_slices_per_group) {
+ fc->num_extra_slices = k - fc->fcp->data_slices_per_group;
+ PARA_NOTICE_LOG("using %d extra slices\n",
+ fc->num_extra_slices);
+ }
+ }
+ fc->stream_start = *now;
+ fc->first_stream_chunk = mmd->current_chunk;
+ g->first_chunk = mmd->current_chunk;
+ g->num = 0;
+ } else {
+ g->first_chunk += g->num_chunks;
+ g->num++;
+ }
+ if (g->first_chunk >= mmd->afd.afhi.chunks_total)
+ return 0;
+ if (need_audio_header(fc, vsst))
+ g->num_header_slices = num_slices(vsst->header_len, fc);
+ else
+ g->num_header_slices = 0;
+ afh_get_chunk(g->first_chunk, &mmd->afd.afhi, vsst->map, &start_buf,
+ &len);
+ data_slices = k - g->num_header_slices;
+ assert(data_slices);
+ max_data_size = slice_bytes * data_slices;
+ g->bytes = 0;
+ for (i = g->first_chunk; i < mmd->afd.afhi.chunks_total; i++) {
+ afh_get_chunk(i, &mmd->afd.afhi, vsst->map, &buf, &len);
+ if (g->bytes + len > max_data_size)
+ break;
+ g->bytes += len;
+ }
+ g->num_chunks = i - g->first_chunk;
+ assert(g->num_chunks);
+ fc->current_slice_num = 0;
+
+ /* setup header slices */
+ buf = vsst->header_buf;
+ for (i = 0; i < g->num_header_slices; i++) {
+ fc->src_data[i] = (const unsigned char *)buf;
+ buf += slice_bytes;
+ }
+
+ /* setup data slices */
+ buf = start_buf;
+ for (i = g->num_header_slices; i < k; i++) {
+ if (buf + slice_bytes > vsst->map + mmd->size)
+ /*
+ * Can not use the memory mapped audio file for this
+ * slice as it goes beyond the map. This slice will not
+ * be fully used.
+ */
+ break;
+ fc->src_data[i] = (const unsigned char *)buf;
+ buf += slice_bytes;
+ }
+ if (i < k) {
+ uint32_t payload_size = vsst->map + mmd->size - buf;
+ memcpy(fc->extra_src_buf, buf, payload_size);
+ fc->src_data[i] = fc->extra_src_buf;
+ i++;
+ /* use arbitrary data for all remaining slices */
+ buf = vsst->map;
+ for (; i < k; i++)
+ fc->src_data[i] = (const unsigned char *)buf;
+ }
+
+ /* setup group timing */
+ tv_scale(g->first_chunk - fc->first_stream_chunk, chunk_tv, &tmp);
+ tv_add(&fc->stream_start, &tmp, &g->start);
+ if (g->num) /* quick hack to avoid buffer underruns */
+ g->start.tv_sec--;
+ tv_scale(g->num_chunks, chunk_tv, &tmp); /* group duration */
+ tv_divide(fc->fcp->slices_per_group + fc->num_extra_slices,
+ &tmp, &g->slice_duration);
+
+ PARA_DEBUG_LOG("FEC group %d: %d chunks (%d - %d), %d header slices, %d data slices\n",
+ g->num, g->num_chunks, g->first_chunk,
+ g->first_chunk + g->num_chunks - 1,
+ g->num_header_slices, data_slices
+ );
+ PARA_DEBUG_LOG("durations (group/chunk/slice): %lu/%lu/%lu\n",
+ tv2ms(&tmp), tv2ms(chunk_tv), tv2ms(&g->slice_duration));
+ return 1;
+}
+
+static int compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+ if (fc->first_stream_chunk < 0 || fc->current_slice_num
+ == fc->fcp->slices_per_group + fc->num_extra_slices) {
+ int ret = setup_next_fec_group(fc, vsst);
+ if (ret <= 0)
+ return ret;
+ }
+ write_fec_header(fc, vsst);
+ fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
+ fc->current_slice_num,
+ fc->fcp->max_slice_bytes - FEC_HEADER_SIZE);
+ return 1;
+}
+
+/**
+ * Return a buffer that marks the end of the stream.
+ *
+ * \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.
+ */
+size_t vss_get_fec_eof_packet(const char **buf)
+{
+ static const char fec_eof_packet[FEC_HEADER_SIZE] = FEC_EOF_PACKET;
+ *buf = fec_eof_packet;
+ return FEC_HEADER_SIZE;
+}
+
+/**
+ * Add one entry to the list of active fec clients.
+ *
+ * \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.
+ */
+int vss_add_fec_client(struct fec_client_parms *fcp, struct fec_client **result)
+{
+ 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 *));
+ fc->enc_buf = para_calloc(fc->fcp->max_slice_bytes);
+ fc->num_extra_slices = 0;
+ fc->extra_src_buf = para_calloc(fc->fcp->max_slice_bytes);
+ fc->next_header_time.tv_sec = 0;
+ para_list_add(&fc->node, &fec_client_list);
+ *result = fc;
+ return 1;
+err:
+ fec_free(fc->parms);
+ free(fc);
+ *result = NULL;
+ return ret;
+}
+
+/**
+ * Remove one entry from the list of active fec clients.
+ *
+ * \param fc The client to be removed.
+ */
+void vss_del_fec_client(struct fec_client *fc)
+{
+ list_del(&fc->node);
+ free(fc->src_data);
+ free(fc->enc_buf);
+ free(fc->extra_src_buf);
+ fec_free(fc->parms);
+ free(fc);
+}
+
+/*
+ * 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
+ *
+ * next = stream_start + (first_group_chunk - first_stream_chunk)
+ * * chunk_time + slice_num * slice_time
+ */
+static int next_slice_is_due(struct fec_client *fc, struct timeval *diff)
+{
+ struct timeval tmp, next;
+ int ret;
+
+ if (fc->first_stream_chunk < 0)
+ return 1;
+ tv_scale(fc->current_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 void compute_slice_timeout(struct timeval *timeout)
+{
+ 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;
+ }
+}