don't allow 0 pacing_bytes_per_ms & fix smaller bugs (holepunchto#261)

Author: jthomas43

src/udx.c

@@ -1064,6 +1064,7 @@ process_packet (udx_socket_t *socket, char *buf, ssize_t buf_len, struct sockadd
   uint32_t lost = stream->lost;
   uint32_t prior_remote_acked = stream->remote_acked;
   bool ack_advanced = seq_diff(ack, prior_remote_acked) > 0;
+  bool data_inflight = stream->remote_acked != stream->seq;
 
   buf += UDX_HEADER_SIZE;
   buf_len -= UDX_HEADER_SIZE;
@@ -1263,8 +1264,8 @@ process_packet (udx_socket_t *socket, char *buf, ssize_t buf_len, struct sockadd
     }
   }
 
-  if (stream->packets_tx) {
-    // don't generate rates / do congestion control if we've never sent a packet..
+  if (data_inflight) {
+    // don't generate rates / do congestion control if nothing was in flight, and thus nothing could be acked and no new samples are generated
     udx__rate_gen(stream, delivered, lost, &rs);
     bbr_main(stream, &rs);
   }
@@ -1493,8 +1494,6 @@ send_stream_packets (udx_socket_t *socket, udx_stream_t *stream) {
     if (rc == UV_EAGAIN) {
       return false;
     }
-    // todo: do we actually want to do this for state packets?
-    udx__rate_pkt_sent(stream, pkt);
 
     // if this ACK packet acks the remote's END packet, advance from ENDING_REMOTE -> ENDED_REMOTE
     if ((stream->status & UDX_STREAM_SHOULD_END_REMOTE) == UDX_STREAM_END_REMOTE && seq_compare(stream->remote_ended, stream->ack) <= 0) {
@@ -1538,9 +1537,6 @@ send_stream_packets (udx_socket_t *socket, udx_stream_t *stream) {
       return false;
     }
 
-    // todo: do we want to generate rate info on this packet
-    udx__rate_pkt_sent(stream, pkt);
-
     stream->packets_tx++;
     stream->bytes_tx += pkt->size;
 

src/udx_bbr.c

@@ -84,16 +84,11 @@ bbr_extra_acked (udx_stream_t *stream) {
   return max_uint32(stream->bbr.extra_acked[0], stream->bbr.extra_acked[1]);
 }
 
-static uint64_t
-bbr_rate_in_bytes (udx_stream_t *stream, double bw, double gain) {
-  uint32_t mss = udx__max_payload(stream);
-
-  return bw * mss * gain * bbr_pacing_margin_percent;
-}
-
 static uint64_t
 bbr_bw_to_pacing_rate (udx_stream_t *stream, double bw, double gain) {
-  return bbr_rate_in_bytes(stream, bw, gain);
+  uint32_t mss = udx__max_payload(stream);
+  uint64_t bpms = bw * mss * gain * bbr_pacing_margin_percent;
+  return max_uint64(bpms, 1);
 }
 
 static void
@@ -131,7 +126,7 @@ static void
 bbr_save_cwnd (udx_stream_t *stream) {
   // save last known cwnd when entering recovery, we use it to restore
   // after completing recovery successfully
-  if (stream->bbr.prev_ca_state < UDX_CA_RECOVERY && stream->bbr.state != UDX_BBR_MIN_PROBE_RTT_MODE_MS) {
+  if (stream->bbr.prev_ca_state < UDX_CA_RECOVERY && stream->bbr.state != UDX_BBR_STATE_PROBE_RTT) {
     stream->bbr.prior_cwnd = stream->cwnd;
   } else {
     stream->bbr.prior_cwnd = max_uint32(stream->bbr.prior_cwnd, stream->cwnd);