X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/db2c19dcee351f69e2ce40902a8e92ecca4bac8c..9f28e855aad11d25c0a69a7e59825c07bdefcafe:/server/speaker-network.c

diff --git a/server/speaker-network.c b/server/speaker-network.c
index c81b7db..40abca5 100644
--- a/server/speaker-network.c
+++ b/server/speaker-network.c
@@ -32,6 +32,7 @@
 #include <assert.h>
 #include <net/if.h>
 #include <ifaddrs.h>
+#include <errno.h>
 
 #include "configuration.h"
 #include "syscalls.h"
@@ -106,11 +107,6 @@ static void network_init(void) {
   socklen_t len;
   char *sockname, *ssockname;
 
-  /* Override sample format */
-  config->sample_format.rate = 44100;
-  config->sample_format.channels = 2;
-  config->sample_format.bits = 16;
-  config->sample_format.byte_format = AO_FMT_BIG;
   res = get_address(&config->broadcast, &pref, &sockname);
   if(!res) exit(-1);
   if(config->broadcast_from.n) {
@@ -122,14 +118,7 @@ static void network_init(void) {
                    res->ai_socktype,
                    res->ai_protocol)) < 0)
     fatal(errno, "error creating broadcast socket");
-  if((res->ai_family == PF_INET
-      && IN_MULTICAST(
-           ntohl(((struct sockaddr_in *)res->ai_addr)->sin_addr.s_addr)
-         ))
-     || (res->ai_family == PF_INET6
-         && IN6_IS_ADDR_MULTICAST(
-               &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr
-            ))) {
+  if(multicast(res->ai_addr)) {
     /* Multicasting */
     switch(res->ai_family) {
     case PF_INET: {
@@ -155,7 +144,11 @@ static void network_init(void) {
     if(getifaddrs(&ifs) < 0)
       fatal(errno, "error calling getifaddrs");
     while(ifs) {
+      /* (At least on Darwin) IFF_BROADCAST might be set but ifa_broadaddr
+       * still a null pointer.  It turns out that there's a subsequent entry
+       * for he same interface which _does_ have ifa_broadaddr though... */
       if((ifs->ifa_flags & IFF_BROADCAST)
+         && ifs->ifa_broadaddr
          && sockaddr_equal(ifs->ifa_broadaddr, res->ai_addr))
         break;
       ifs = ifs->ifa_next;
@@ -189,14 +182,13 @@ static void network_init(void) {
     fatal(errno, "error connecting broadcast socket to %s", sockname);
   /* Select an SSRC */
   gcry_randomize(&rtp_id, sizeof rtp_id, GCRY_STRONG_RANDOM);
-  info("selected network backend, sending to %s", sockname);
 }
 
 /** @brief Play over the network */
 static size_t network_play(size_t frames) {
   struct rtp_header header;
   struct iovec vec[2];
-  size_t bytes = frames * device_bpf, written_frames;
+  size_t bytes = frames * bpf, written_frames;
   int written_bytes;
   /* We transmit using RTP (RFC3550) and attempt to conform to the internet
    * AVT profile (RFC3551). */
@@ -212,8 +204,8 @@ static size_t network_play(size_t frames) {
     /* Find the number of microseconds elapsed since rtp_time=0 */
     delta = tvsub_us(now, rtp_time_0);
     assert(delta <= UINT64_MAX / 88200);
-    target_rtp_time = (delta * playing->format.rate
-                       * playing->format.channels) / 1000000;
+    target_rtp_time = (delta * config->sample_format.rate
+                       * config->sample_format.channels) / 1000000;
     /* Overflows at ~6 years uptime with 44100Hz stereo */
 
     /* rtp_time is the number of samples we've played.  NB that we play
@@ -272,7 +264,7 @@ static size_t network_play(size_t frames) {
   if(bytes > NETWORK_BYTES - sizeof header) {
     bytes = NETWORK_BYTES - sizeof header;
     /* Always send a whole number of frames */
-    bytes -= bytes % device_bpf;
+    bytes -= bytes % bpf;
   }
   /* "The RTP clock rate used for generating the RTP timestamp is independent
    * of the number of channels and the encoding; it equals the number of
@@ -298,23 +290,25 @@ static size_t network_play(size_t frames) {
   } else
     audio_errors /= 2;
   written_bytes -= sizeof (struct rtp_header);
-  written_frames = written_bytes / device_bpf;
+  written_frames = written_bytes / bpf;
   /* Advance RTP's notion of the time */
-  rtp_time += written_frames * playing->format.channels;
+  rtp_time += written_frames * config->sample_format.channels;
   return written_frames;
 }
 
 static int bfd_slot;
 
 /** @brief Set up poll array for network play */
-static void network_beforepoll(void) {
+static void network_beforepoll(int *timeoutp) {
   struct timeval now;
   uint64_t target_us;
   uint64_t target_rtp_time;
+  const int64_t samples_per_second = config->sample_format.rate
+                                   * config->sample_format.channels;
   const int64_t samples_ahead = ((uint64_t)RTP_AHEAD_MS
-                                 * config->sample_format.rate
-                                 * config->sample_format.channels
+                                 * samples_per_second
                                  / 1000);
+  int64_t lead, ahead_ms;
   
   /* If we're starting then initialize the base time */
   if(!rtp_time)
@@ -327,8 +321,17 @@ static void network_beforepoll(void) {
   target_rtp_time = (target_us * config->sample_format.rate
                                * config->sample_format.channels)
                      / 1000000;
-  if((int64_t)(rtp_time - target_rtp_time) < samples_ahead)
+  lead = rtp_time - target_rtp_time;
+  if(lead < samples_ahead)
+    /* We've not reached the desired lead, write as fast as we can */
     bfd_slot = addfd(bfd, POLLOUT);
+  else {
+    /* We've reached the desired lead, we can afford to wait a bit even if the
+     * IP stack thinks it can accept more. */
+    ahead_ms = 1000 * (lead - samples_ahead) / samples_per_second;
+    if(ahead_ms < *timeoutp)
+      *timeoutp = ahead_ms;
+  }
 }
 
 /** @brief Process poll() results for network play */
@@ -341,7 +344,7 @@ static int network_ready(void) {
 
 const struct speaker_backend network_backend = {
   BACKEND_NETWORK,
-  FIXED_FORMAT,
+  0,
   network_init,
   0,                                    /* activate */
   network_play,