+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;
+};
+
+static struct list_head fec_client_list;
+
+struct fec_slice {
+ uint8_t num;
+ uint16_t bytes;
+};
+
+struct fec_group {
+ uint32_t num;
+ uint32_t bytes;
+ uint32_t first_chunk;
+ uint32_t num_chunks;
+ struct timeval duration;
+ struct timeval start;
+ struct timeval slice_duration;
+};
+
+struct fec_client {
+ struct fec_client_parms *fcp;
+ struct fec_parms *parms;
+ struct list_head node;
+ struct timeval stream_start;
+ int first_stream_chunk;
+ struct fec_group group;
+ struct fec_slice slice;
+ const unsigned char **src_data;
+ unsigned char *extra_src_buf;
+ size_t extra_src_buf_size;
+ unsigned char *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)
+{
+ 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;
+}
+
+static void setup_fec_group(struct fec_client *fc, struct vss_task *vsst)
+{
+ uint32_t num_bytes = 0, chunk_num, max_group_size, last_payload_size;
+ int i, k = fc->fcp->data_slices_per_group;
+ const unsigned char *start_buf = NULL;
+ struct timeval tmp, *chunk_tv = vss_chunk_time();
+
+ assert(chunk_tv);
+ max_group_size = (fc->fcp->max_slice_bytes - FEC_HEADER_SIZE) * k;
+ chunk_num = fc->group.first_chunk;
+ for (;;) {
+ const unsigned char *buf;
+ size_t len;
+
+ if (chunk_num >= mmd->afd.afhi.chunks_total)
+ break;
+ afh_get_chunk(chunk_num, &mmd->afd.afhi, vsst->map, (const char **)&buf, &len);
+ if (!start_buf)
+ start_buf = buf;
+ if (num_bytes + len > max_group_size)
+ break;
+ chunk_num++;
+ num_bytes += len;
+ }
+ assert(start_buf);
+ fc->group.num_chunks = chunk_num - fc->group.first_chunk;
+ fc->group.num++;
+ fc->group.bytes = num_bytes;
+ fc->slice.num = 0;
+ fc->slice.bytes = ROUND_UP(num_bytes, k) / k;
+
+ /* The last slice will not be fully used */
+ last_payload_size = num_bytes % fc->slice.bytes;
+ if (!last_payload_size)
+ last_payload_size = fc->slice.bytes;
+
+ tv_scale(fc->group.num_chunks, chunk_tv, &fc->group.duration);
+ tv_scale(fc->group.first_chunk - fc->first_stream_chunk, chunk_tv,
+ &tmp);
+ tv_add(&fc->stream_start, &tmp, &fc->group.start);
+ tv_divide(fc->fcp->slices_per_group, &fc->group.duration,
+ &fc->group.slice_duration);
+
+ for (i = 0; i < k; i++)
+ fc->src_data[i] = start_buf + i * fc->slice.bytes;
+
+ if ((char *)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);
+ 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;
+ }
+
+}
+
+/**
+ * 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)
+{
+ 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);
+}
+
+/**
+ * Return a buffer that marks the end of the stream.
+ *
+ * \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] =
+ "\xec\x0d\xcc\xfe\0\0\0\0"
+ "\0\0\0\0\0\0\0\0"
+ "\0\0\0\0\0\0\0\0"
+ "\0\0\0\0\0\0\0\0";
+ *buf = fec_eof_packet;
+ return FEC_HEADER_SIZE;
+}
+
+static void compute_next_fec_slice(struct fec_client *fc, struct vss_task *vsst)
+{
+ 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;
+ setup_fec_group(fc, vsst);
+ } else if (fc->slice.num == fc->fcp->slices_per_group) {
+ fc->group.first_chunk += fc->group.num_chunks;
+ setup_fec_group(fc, vsst);
+
+ }
+ 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);
+ }
+ write_fec_header(fc);
+ fec_encode(fc->parms, fc->src_data, fc->enc_buf + FEC_HEADER_SIZE,
+ fc->slice.num, fc->slice.bytes);
+}
+
+/**
+ * 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 *));
+ 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 result 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->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;
+ int ret = next_slice_is_due(fc, &diff);
+
+ // PARA_NOTICE_LOG("diff: %lu, ret: %d\n", tv2ms(&diff), ret);
+ if (ret) {
+ timeout->tv_sec = 0;
+ timeout->tv_usec = 0;
+ goto out;
+ }
+ /* timeout = min(timeout, diff) */
+ if (tv_diff(&diff, timeout, NULL) < 0)
+ *timeout = diff;
+ }
+out:
+ return;
+ PARA_NOTICE_LOG("slice timeout: %lu:%lu\n", (long unsigned)timeout->tv_sec, (long unsigned)timeout->tv_usec);
+}