[vlc-devel] [PATCHv4 1/3] access: Add satip access module
Rémi Denis-Courmont
remi at remlab.net
Sat May 28 18:15:25 CEST 2016
On Friday 27 May 2016 11:43:26 Julian Scheel wrote:
> Thanks for the review.
>
> On 27.05.2016 10:49, Rémi Denis-Courmont wrote:
> > Le 2016-05-26 16:51, Julian Scheel a écrit :
> >> +static int check_rtp_seq(access_t *access, block_t *block)
> >> +{
> >> + access_sys_t *sys = access->p_sys;
> >> + uint16_t seq_nr = block->p_buffer[2] << 8 | block->p_buffer[3];
> >> +
> >> + if (seq_nr == sys->last_seq_nr) {
> >> + msg_Warn(access, "Received duplicate packet (seq_nr=%u)",
> >> seq_nr);
> >> + return VLC_EGENERIC;
> >> + } else if (seq_nr < ++sys->last_seq_nr) {
> >
> > So what if last_seq_nr was 65535 before the increment?
>
> last_seq_nr will be wrapped to 0, just as seq_nr, so no warning will occur.
So no. 65533 after no. 65534 causes a warning, but no. 65534 after no. 65535
does not. That does not seem right.
> >> + msg_Warn(access, "Received out of order packet (seq_nr=%u <
> >> %u)",
> >> + seq_nr, sys->last_seq_nr);
> >
> > PRIu16, same below.
>
> Ack.
>
> >> + return VLC_EGENERIC;
> >> + } else if (sys->last_seq_nr > 1 && seq_nr > sys->last_seq_nr) {
> >> + msg_Warn(access, "Gap in seq_nr (%u > %u), probably lost a
> >> packet",
> >> + seq_nr, sys->last_seq_nr);
> >> + }
> >> +
> >> + sys->last_seq_nr = seq_nr;
> >> + return 0;
> >> +}
> >> +
> >> +static void satip_teardown(void *data) {
> >> + access_t *access = data;
> >> + access_sys_t *sys = access->p_sys;
> >> +
> >> + int canc = vlc_savecancel();
> >
> > You might be better off disabling cancellation
>
> documentation of vlc_savecancel
> vlc_thread.h:645: "Disables thread cancellation."
>
> >> + if (sys->tcp_sock > 0) {
> >> + if (sys->session_id[0] > 0) {
> >> + net_Printf(access, sys->tcp_sock,
> >> + "TEARDOWN %s RTSP/1.0\r\n"
> >> + "CSeq: %d\r\n"
> >> + "Session: %s\r\n\r\n",
> >> + sys->control, sys->cseq++, sys->session_id);
> >> + if (rtsp_handle(access) != RTSP_RESULT_OK)
> >> + msg_Warn(access, "Failed to teardown RTSP session");
> >> + }
> >> + }
> >> + vlc_restorecancel(canc);
> >
> > Won't this lock up if the connection remains congested for writing?
> > (ditto other use of net_Printf())
>
> Hm, I don't see why that would ever happen.
I don´t see how you could prevent a TCP connection from getting congested for
arbitrarily long. That would be under the control of the network and the
remote peer.
> Assuming it enters a state of write congestion would you mind suggesting
> some approach to properly deal with it?
>
> >> +}
> >> +
> >> +static void *satip_thread(void *data) {
> >> + access_t *access = data;
> >> + access_sys_t *sys = access->p_sys;
> >> + int sock = sys->udp_sock;
> >> + volatile int sleeps = 0;
> >> + block_t *block = NULL;
> >> + ssize_t len;
> >> + mtime_t next_keepalive = mdate() + sys->keepalive_interval *
> >> 1000 * 1000;
> >> +
> >> +#ifdef HAVE_RECVMMSG
> >> + struct mmsghdr msgs[VLEN];
> >> + struct iovec iovecs[VLEN];
> >> + int retval, i;
> >> + memset(msgs, 0, sizeof(msgs));
> >> +#endif
> >> +
> >> + vlc_cleanup_push(satip_teardown, access);
> >> + while (sleeps < 100) {
> >> +#ifdef HAVE_RECVMMSG
> >> + if (alloc_input_blocks(access) != 0) {
> >> + msg_Err(access, "Failed to allocate memory for input
> >> buffers");
> >> + break;
> >> + }
> >> +
> >> + for(i = 0; i < VLEN; ++i) {
> >> + iovecs[i].iov_base = sys->input_blocks[i]->p_buffer;
> >> + iovecs[i].iov_len = RTSP_RECEIVE_BUFFER;
> >> + msgs[i].msg_hdr.msg_iov = &iovecs[i];
> >> + msgs[i].msg_hdr.msg_iovlen = 1;
> >> + }
> >> + retval = recvmmsg(sock, msgs, VLEN, MSG_WAITFORONE, NULL);
> >> + if (retval == -1) {
> >> + usleep(20000);
> >
> > No obsolete/removed function thanks.
>
> Ack, changed to msleep.
>
> >> + ++sleeps;
> >> + continue;
> >> + }
> >> +
> >> + sleeps = 0;
> >> + for(i = 0; i < retval; ++i) {
> >> + len = msgs[i].msg_len;
> >> + block = sys->input_blocks[i];
> >> + if (check_rtp_seq(access, block))
> >> + continue;
> >> +
> >> + block->p_buffer += RTP_HEADER_SIZE;
> >> + block->i_buffer = len - RTP_HEADER_SIZE;
> >> + block_FifoPut(sys->fifo, block);
> >> + sys->input_blocks[i] = NULL;
> >> + }
> >> +#else
> >> + struct pollfd ufd;
> >> +
> >> + ufd.fd = sock;
> >> + ufd.events = POLLIN;
> >> + if (poll(&ufd, 1, 20) == -1) {
> >
> > No. Compute your deadline correctly.
>
> Ack, dropped sleeps and am using mdate() - RECV_TIMEOUT now,
>
> >> + ++sleeps;
> >> + continue;
> >> + }
> >> +
> >> + block = block_Alloc(RTSP_RECEIVE_BUFFER);
> >> + if (block == NULL) {
> >> + msg_Err(access, "Failed to allocate memory for input
> >> buffer");
> >> + break;
> >> + }
> >> +
> >> + len = recv(sock, block->p_buffer, RTSP_RECEIVE_BUFFER, 0);
> >> + if (len < RTP_HEADER_SIZE) {
> >> + block_Release(block);
> >> + continue;
> >> + }
> >> +
> >> + if (check_rtp_seq(access, block)) {
> >> + block_Release(block);
> >> + continue;
> >> + }
> >> + sleeps = 0;
> >> + block->p_buffer += RTP_HEADER_SIZE;
> >> + block->i_buffer = len - RTP_HEADER_SIZE;
> >> + block_FifoPut(sys->fifo, block);
> >> +#endif
> >> +
> >> + if (sys->keepalive_interval > 0 && mdate() > next_keepalive) {
> >> + net_Printf(access, sys->tcp_sock,
> >> + "OPTIONS %s RTSP/1.0\r\n"
> >> + "CSeq: %d\r\n"
> >> + "Session: %s\r\n\r\n",
> >> + sys->control, sys->cseq++, sys->session_id);
> >> + if (rtsp_handle(access) != RTSP_RESULT_OK)
> >> + msg_Warn(access, "Failed to keepalive RTSP session");
> >> +
> >> + next_keepalive = mdate() + sys->keepalive_interval *
> >> 1000 * 1000;
> >> + }
> >> + }
> >> + vlc_cleanup_pop();
> >> + satip_teardown(access);
> >> +
> >> + msg_Dbg(access, "timed out waiting for data...");
> >> + vlc_fifo_Lock(sys->fifo);
> >> + sys->woken = true;
> >> + vlc_fifo_Signal(sys->fifo);
> >> + vlc_fifo_Unlock(sys->fifo);
> >> +
> >> + return NULL;
> >> +}
> >> +
> >> +static block_t* satip_block(access_t *access) {
> >> + access_sys_t *sys = access->p_sys;
> >> + block_t *block;
> >> +
> >> + vlc_fifo_Lock(sys->fifo);
> >> +
> >> + while (vlc_fifo_IsEmpty(sys->fifo)) {
> >> + if (sys->woken)
> >> + break;
> >> + vlc_fifo_Wait(sys->fifo);
> >> + /* Make sure there is no cancellation point other than this
> >> one^^.
> >> + * If you need one, be sure to push cleanup of p_block. */
> >> + }
> >> +
> >> + int canc = vlc_savecancel();
> >> + block = vlc_fifo_DequeueUnlocked(sys->fifo);
> >> + sys->woken = false;
> >> + vlc_fifo_Unlock(sys->fifo);
> >> +
> >> + vlc_restorecancel(canc);
> >> + return block;
> >> +}
> >> +
> >> +static int satip_control(access_t *access, int i_query, va_list args) {
> >> + bool *pb_bool;
> >> + int64_t *pi_64;
> >> +
> >> + switch(i_query)
> >> + {
> >> + case ACCESS_CAN_CONTROL_PACE:
> >> + case ACCESS_CAN_SEEK:
> >> + pb_bool = (bool*)va_arg(args, bool*);
> >> + *pb_bool = false;
> >> + break;
> >> +
> >> + case ACCESS_CAN_PAUSE:
> >> + pb_bool = (bool*)va_arg(args, bool*);
> >> + *pb_bool = false;
> >> + break;
> >> +
> >> + case ACCESS_GET_PTS_DELAY:
> >> + pi_64 = (int64_t*)va_arg(args, int64_t *);
> >> + *pi_64 = INT64_C(1000) * var_InheritInteger(access,
> >> "live-caching");
> >> + break;
> >> +
> >> + default:
> >> + return VLC_EGENERIC;
> >> +
> >> + }
> >> + return VLC_SUCCESS;
> >> +}
> >> +
> >> +/* Bind two adjacent free ports, of which the first one is even (for
> >> RTP data)
> >> + * and the second is odd (RTCP). This is a requirement of the satip
> >> + * specification */
> >> +static int satip_bind_ports(access_t *access)
> >> +{
> >> + access_sys_t *sys = access->p_sys;
> >> + uint8_t rnd;
> >> +
> >> + vlc_rand_bytes(&rnd, 1);
> >> + sys->udp_port = 9000 + (rnd * 2); /* randomly chosen, even start
> >> point */
> >> + while (sys->udp_sock < 0 && sys->udp_port < 65535) {
> >> + sys->udp_sock = net_OpenDgram(access, "0.0.0.0",
> >> sys->udp_port, NULL,
> >> + 0, IPPROTO_UDP);
> >> + if (sys->udp_sock < 0) {
> >> + sys->udp_port += 2;
> >> + continue;
> >> + }
> >> +
> >> + sys->rtcp_sock = net_OpenDgram(access, "0.0.0.0",
> >> sys->udp_port + 1, NULL,
> >> + 0, IPPROTO_UDP);
> >> + if (sys->rtcp_sock < 0) {
> >> + close(sys->udp_sock);
> >> + sys->udp_port += 2;
> >> + continue;
> >> + }
> >> + }
> >> +
> >> + if (sys->udp_sock < 0) {
> >> + msg_Err(access, "Could not open two adjacent ports for RTP
> >> and RTCP data");
> >> + return VLC_EGENERIC;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int satip_open(access_t *access) {
> >> + access_sys_t *sys;
> >> + vlc_url_t url;
> >> +
> >> + bool multicast = var_InheritBool(access, "satip-multicast");
> >> +
> >> + access->p_sys = sys = calloc(1, sizeof(*sys));
> >> + if (sys == NULL)
> >> + return VLC_ENOMEM;
> >> +
> >> + msg_Dbg(access, "try to open '%s'", access->psz_location);
> >> +
> >> + sys->udp_sock = -1;
> >> + sys->rtcp_sock = -1;
> >> +
> >> + /* convert url to lowercase, some famous m3u playlists for satip
> >> contain
> >> + * uppercase parameters while most (all?) satip servers do only
> >> understand
> >> + * parameters matching lowercase spelling as defined in the
> >> specification
> >> + * */
> >> + char *psz_lower_location = strdup(access->psz_location);
> >> + if (psz_lower_location == NULL)
> >> + goto error;
> >> +
> >> + for (unsigned i = 0; i < strlen(psz_lower_location); i++)
> >> + psz_lower_location[i] = tolower(psz_lower_location[i]);
> >> +
> >> + vlc_UrlParse(&url, psz_lower_location);
> >> + if (url.i_port <= 0)
> >> + url.i_port = RTSP_DEFAULT_PORT;
> >> +
> >> + msg_Dbg(access, "connect to host '%s'", url.psz_host);
> >> + sys->tcp_sock = net_ConnectTCP(access, url.psz_host, url.i_port);
> >> + if (sys->tcp_sock < 0) {
> >> + msg_Err(access, "Failed to connect to RTSP server %s:%d",
> >> + url.psz_host, url.i_port);
> >> + goto error;
> >> + }
> >> + setsockopt (sys->tcp_sock, SOL_SOCKET, SO_KEEPALIVE, &(int){ 1
> >> }, sizeof (int));
> >
> > This is useless if you do application layer keep-alives.
>
> Ack, dropped.
>
> >> +
> >> + if (asprintf(&sys->content_base, "rtsp://%s:%d/", url.psz_host,
> >> + url.i_port) < 0) {
> >> + sys->content_base = NULL;
> >> + goto error;
> >> + }
> >> +
> >> + sys->last_seq_nr = 0;
> >> + sys->keepalive_interval = (KEEPALIVE_INTERVAL - KEEPALIVE_MARGIN);
> >> +
> >> + if (multicast) {
> >> + net_Printf(access, sys->tcp_sock,
> >> + "SETUP rtsp://%s RTSP/1.0\r\n"
> >> + "CSeq: %d\r\n"
> >> + "Transport: RTP/AVP;multicast\r\n\r\n",
> >> + psz_lower_location, sys->cseq++);
> >> + } else {
> >> + /* open UDP socket to acquire a free port to use */
> >> + if (satip_bind_ports(access))
> >> + goto error;
> >> +
> >> + net_Printf(access, sys->tcp_sock,
> >> + "SETUP rtsp://%s RTSP/1.0\r\n"
> >> + "CSeq: %d\r\n"
> >> + "Transport: RTP/AVP;unicast;client_port=%d-%d\r\n\r\n",
> >> + psz_lower_location, sys->cseq++, sys->udp_port,
> >> sys->udp_port + 1);
> >> + }
> >> +
> >> + if (rtsp_handle(access) != RTSP_RESULT_OK) {
> >> + msg_Err(access, "Failed to setup RTSP session");
> >> + goto error;
> >> + }
> >> +
> >> + if (asprintf(&sys->control, "%sstream=%d", sys->content_base,
> >> sys->stream_id) < 0) {
> >> + sys->control = NULL;
> >> + goto error;
> >> + }
> >> +
> >> + /* Open UDP socket for reading if not done */
> >> + if (multicast) {
> >> + sys->udp_sock = net_OpenDgram(access, sys->udp_address,
> >> sys->udp_port, "", sys->udp_port, IPPROTO_UDP);
> >> + if (sys->udp_sock < 0) {
> >> + msg_Err(access, "Failed to open UDP socket for listening.");
> >> + goto error;
> >> + }
> >> +
> >> + sys->rtcp_sock = net_OpenDgram(access, sys->udp_address,
> >> sys->udp_port + 1, "", sys->udp_port + 1, IPPROTO_UDP);
> >> + if (sys->rtcp_sock < 0) {
> >> + msg_Err(access, "Failed to open RTCP socket for
> >> listening.");
> >> + goto error;
> >> + }
> >> + }
> >> + net_SetCSCov(sys->udp_sock, -1, RTP_HEADER_SIZE);
> >> +
> >> + net_Printf(access, sys->tcp_sock,
> >> + "PLAY %s RTSP/1.0\r\n"
> >> + "CSeq: %d\r\n"
> >> + "Session: %s\r\n\r\n",
> >> + sys->control, sys->cseq++, sys->session_id);
> >> +
> >> + if (rtsp_handle(access) != RTSP_RESULT_OK) {
> >> + msg_Err(access, "Failed to play RTSP session");
> >> + goto error;
> >> + }
> >> +
> >> + sys->fifo = block_FifoNew();
> >> + if (!sys->fifo) {
> >> + msg_Err(access, "Failed to allocate block fifo.");
> >> + goto error;
> >> + }
> >> + sys->fifo_size = var_InheritInteger(access, "satip-buffer");
> >> +
> >> + if (vlc_clone(&sys->thread, satip_thread, access,
> >> VLC_THREAD_PRIORITY_INPUT)) {
> >> + msg_Err(access, "Failed to create worker thread.");
> >> + goto error;
> >> + }
> >> +
> >> + access->pf_control = satip_control;
> >> + access->pf_block = satip_block;
> >> +
> >> + free(psz_lower_location);
> >> + vlc_UrlClean(&url);
> >> + return VLC_SUCCESS;
> >> +
> >> +error:
> >> + if (psz_lower_location)
> >> + free(psz_lower_location);
> >> +
> >> + vlc_UrlClean(&url);
> >> + satip_close(access);
> >> + return VLC_EGENERIC;
> >> +}
> >> +
> >> +static void satip_close(access_t *access) {
> >> + access_sys_t *sys = access->p_sys;
> >> +
> >> + if (sys->thread) {
> >> + vlc_cancel(sys->thread);
> >> + vlc_join(sys->thread, NULL);
> >> + }
> >> +
> >> + if (sys->fifo)
> >> + block_FifoRelease(sys->fifo);
> >> +
> >> +#ifdef HAVE_RECVMMSG
> >> + for (int i = 0; i < VLEN; i++) {
> >> + if (sys->input_blocks[i])
> >> + block_Release(sys->input_blocks[i]);
> >> + }
> >> +#endif
> >> +
> >> + if (sys->udp_sock > 0)
> >> + net_Close(sys->udp_sock);
> >> + if (sys->rtcp_sock > 0)
> >> + net_Close(sys->rtcp_sock);
> >> + if (sys->tcp_sock > 0)
> >> + net_Close(sys->tcp_sock);
> >> +
> >> + free(sys->content_base);
> >> + free(sys->control);
> >> + free(sys);
> >> +}
> >> diff --git a/po/POTFILES.in b/po/POTFILES.in
> >> index 6451cc2..758fc9b 100644
> >> --- a/po/POTFILES.in
> >> +++ b/po/POTFILES.in
> >> @@ -248,6 +248,7 @@ modules/access/rtsp/real_sdpplin.c
> >>
> >> modules/access/rtsp/real_sdpplin.h
> >> modules/access/rtsp/rtsp.c
> >> modules/access/rtsp/rtsp.h
> >>
> >> +modules/access/satip.c
> >>
> >> modules/access/screen/mac.c
> >> modules/access/screen/screen.c
> >> modules/access/screen/screen.h
>
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--
Rémi Denis-Courmont
http://www.remlab.net/
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