recv buf: issue a warning if unable to set

Issue a warning if unable to set the buffers andreceiving uncompressed
stream, but not not on initial setting, only if increase requested.

The logic is not entirely straightforward - as we are increasing only,
do not assume that the buffer is set to the initial size but rather read
the actual value, which will be less if wasn't possible to set. So the
second attemp issues the warning.

src/rtp/net_udp.c

@@ -1433,6 +1433,19 @@ static int resolve_address(socket_udp *s, const char *addr, uint16_t tx_port)
         return ret;
 }
 
+int
+udp_get_recv_buf(socket_udp *s)
+{
+        int       opt      = 0;
+        socklen_t opt_size = sizeof opt;
+        if (GETSOCKOPT(s->local->tx_fd, SOL_SOCKET, SO_RCVBUF, (sockopt_t) &opt,
+                       &opt_size) != 0) {
+                socket_error("Unable to get socket buffer size");
+                return -1;
+        }
+        return opt;
+}
+
 static bool
 udp_set_buf(socket_udp *s, int sockopt, int size)
 {

src/rtp/net_udp.h

@@ -92,6 +92,7 @@ void	    udp_fd_zero(void);
 void        udp_fd_set(socket_udp *s);
 int         udp_fd_isset(socket_udp *s);
 
+int         udp_get_recv_buf(socket_udp *s);
 bool        udp_set_recv_buf(socket_udp *s, int size);
 bool        udp_set_send_buf(socket_udp *s, int size);
 void        udp_flush_recv_buf(socket_udp *s);

src/rtp/rtp.c

@@ -3945,6 +3945,12 @@ bool rtp_set_recv_buf(struct rtp *session, int bufsize)
         return udp_set_recv_buf(session->rtp_socket, bufsize);
 }
 
+int
+rtp_get_recv_buf(struct rtp *session)
+{
+        return udp_get_recv_buf(session->rtp_socket);
+}
+
 /**
  * Sets sender buffer size
  * @param session the RTP Session

src/rtp/rtp.h

@@ -304,6 +304,7 @@ bool             rtp_set_my_ssrc(struct rtp *session, uint32_t ssrc);
 uint8_t		*rtp_get_userdata(struct rtp *session);
 void 		 rtp_set_recv_iov(struct rtp *session, struct msghdr *m);
 
+int              rtp_get_recv_buf(struct rtp *session);
 bool             rtp_set_recv_buf(struct rtp *session, int bufsize);
 bool             rtp_set_send_buf(struct rtp *session, int bufsize);
 

src/video_rxtx/rtp.cpp

@@ -250,13 +250,13 @@ rtp_video_rxtx::~rtp_video_rxtx()
 
 void rtp_video_rxtx::display_buf_increase_warning(int size)
 {
-        log_msg(LOG_LEVEL_VERBOSE, "\n***\n"
+        log_msg(LOG_LEVEL_INFO, "\n***\n"
                         "Unable to set buffer size to %d B.\n"
 #if defined WIN32
                         "See https://github.com/CESNET/UltraGrid/wiki/Extending-Network-Buffers-%%28Windows%%29 for details.\n",
 #else
-                        "Please set net.core.rmem_max value to %d or greater. (see also\n"
-                        "https://github.com/CESNET/UltraGrid/wiki/OS-Setup-UltraGrid)\n"
+                        "Please set net.core.rmem_max value to %d or greater (see also\n"
+                        "https://github.com/CESNET/UltraGrid/wiki/OS-Setup-UltraGrid):\n"
 #ifdef HAVE_MACOSX
                         "\tsysctl -w kern.ipc.maxsockbuf=%d\n"
                         "\tsysctl -w net.inet.udp.recvspace=%d\n"
@@ -301,10 +301,7 @@ struct rtp *rtp_video_rxtx::initialize_network(const char *addr, int recv_port,
                 rtp_set_option(device, RTP_OPT_SEND_BACK, TRUE);
         }
 
-        if (!rtp_set_recv_buf(device, INITIAL_VIDEO_RECV_BUFFER_SIZE)) {
-                display_buf_increase_warning(INITIAL_VIDEO_RECV_BUFFER_SIZE);
-        }
-
+        rtp_set_recv_buf(device, INITIAL_VIDEO_RECV_BUFFER_SIZE);
         rtp_set_send_buf(device, INITIAL_VIDEO_SEND_BUFFER_SIZE);
 
         pdb_add(participants, rtp_my_ssrc(device));

src/video_rxtx/ultragrid_rtp.cpp

@@ -278,7 +278,7 @@ void *ultragrid_rtp_video_rxtx::receiver_loop()
         set_thread_name(__func__);
         struct pdb_e *cp;
         int fr;
-        int last_buf_size = INITIAL_VIDEO_RECV_BUFFER_SIZE;
+        int last_buf_size = rtp_get_recv_buf(m_network_device);
 
 #ifdef SHARED_DECODER
         struct vcodec_state *shared_decoder = new_video_decoder(m_display_device);