X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Ftcp%2Ftcp_output.c;h=089f85a0ea0f6ce1e78f4d89fc9998b203fad831;hb=7ac053b27fee8f9e437cf7b61357943356381061;hp=c135a311fb5d01ac4130b74fd6f9cecab4b078b6;hpb=c44a558164a466a74a4c10d4e7d7dd1b9a4b01dd;p=vpp.git

diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index c135a311fb5..089f85a0ea0 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -559,7 +559,6 @@ tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b)
   tcp_reuse_buffer (vm, b);
   tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK);
   TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc);
-  vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
   tc->rcv_las = tc->rcv_nxt;
 }
 
@@ -631,7 +630,6 @@ tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b)
   tcp_options_write ((u8 *) (th + 1), snd_opts);
 
   vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
-  vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK;
 
   /* Init retransmit timer. Use update instead of set because of
    * retransmissions */
@@ -862,7 +860,7 @@ tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
     {
       flags = TCP_FLAG_RST;
       seq = pkt_th->ack_number;
-      ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
+      ack = (tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0;
     }
   else
     {
@@ -1011,6 +1009,23 @@ tcp_send_syn (tcp_connection_t * tc)
   TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc);
 }
 
+void
+tcp_send_synack (tcp_connection_t * tc)
+{
+  tcp_worker_ctx_t *wrk = tcp_get_worker (tc->c_thread_index);
+  vlib_main_t *vm = wrk->vm;
+  vlib_buffer_t *b;
+  u32 bi;
+
+  /* Get buffer */
+  if (PREDICT_FALSE (tcp_get_free_buffer_index (wrk, &bi)))
+    return;
+
+  b = vlib_get_buffer (vm, bi);
+  tcp_make_synack (tc, b);
+  tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
+}
+
 /**
  * Flush tx frame populated by retransmits and timer pops
  */
@@ -1223,6 +1238,56 @@ tcp_send_ack (tcp_connection_t * tc)
   tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
 }
 
+void
+tcp_program_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
+{
+  if (!(tc->flags & TCP_CONN_SNDACK))
+    {
+      vec_add1 (wrk->pending_acks, tc->c_c_index);
+      tc->flags |= TCP_CONN_SNDACK;
+    }
+}
+
+void
+tcp_program_dupack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
+{
+  if (!(tc->flags & TCP_CONN_SNDACK))
+    {
+      vec_add1 (wrk->pending_acks, tc->c_c_index);
+      tc->flags |= TCP_CONN_SNDACK;
+    }
+  if (tc->pending_dupacks < 255)
+    tc->pending_dupacks += 1;
+}
+
+void
+tcp_send_acks (tcp_worker_ctx_t * wrk)
+{
+  u32 thread_index, *pending_acks;
+  tcp_connection_t *tc;
+  int i, j, n_acks;
+
+  if (!vec_len (wrk->pending_acks))
+    return;
+
+  thread_index = wrk->vm->thread_index;
+  pending_acks = wrk->pending_acks;
+  for (i = 0; i < vec_len (pending_acks); i++)
+    {
+      tc = tcp_connection_get (pending_acks[i], thread_index);
+      tc->flags &= ~TCP_CONN_SNDACK;
+      n_acks = clib_max (1, tc->pending_dupacks);
+      /* If we're supposed to send dupacks but have no ooo data
+       * send only one ack */
+      if (tc->pending_dupacks && !vec_len (tc->snd_sacks))
+	n_acks = 1;
+      for (j = 0; j < n_acks; j++)
+	tcp_send_ack (tc);
+      tc->pending_dupacks = 0;
+    }
+  _vec_len (wrk->pending_acks) = 0;
+}
+
 /**
  * Delayed ack timer handler
  *
@@ -1240,49 +1305,27 @@ tcp_timer_delack_handler (u32 index)
 }
 
 /**
- * Build a retransmit segment
+ * Allocate a new buffer and build a new tcp segment
  *
- * @return the number of bytes in the segment or 0 if there's nothing to
- *         retransmit
+ * @param wrk		tcp worker
+ * @param tc		connection for which the segment will be allocated
+ * @param offset	offset of the first byte in the tx fifo
+ * @param max_deq_byte	segment size
+ * @param[out] b	pointer to buffer allocated
+ *
+ * @return 	the number of bytes in the segment or 0 if buffer cannot be
+ * 		allocated or no data available
  */
-static u32
-tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
-				tcp_connection_t * tc, u32 offset,
-				u32 max_deq_bytes, vlib_buffer_t ** b)
+static int
+tcp_prepare_segment (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+		     u32 offset, u32 max_deq_bytes, vlib_buffer_t ** b)
 {
   u32 bytes_per_buffer = vnet_get_tcp_main ()->bytes_per_buffer;
+  u32 bi, seg_size;
   vlib_main_t *vm = wrk->vm;
   int n_bytes = 0;
-  u32 start, bi, available_bytes, seg_size;
   u8 *data;
 
-  ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
-  ASSERT (max_deq_bytes != 0);
-
-  /*
-   * Make sure we can retransmit something
-   */
-  available_bytes = session_tx_fifo_max_dequeue (&tc->connection);
-  ASSERT (available_bytes >= offset);
-  available_bytes -= offset;
-  if (!available_bytes)
-    return 0;
-  max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
-  max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
-
-  /* Start is beyond snd_congestion */
-  start = tc->snd_una + offset;
-  if (seq_geq (start, tc->snd_congestion))
-    goto done;
-
-  /* Don't overshoot snd_congestion */
-  if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
-    {
-      max_deq_bytes = tc->snd_congestion - start;
-      if (max_deq_bytes == 0)
-	goto done;
-    }
-
   seg_size = max_deq_bytes + MAX_HDRS_LEN;
 
   /*
@@ -1330,7 +1373,7 @@ tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
 	    }
 	}
 
-      tcp_get_free_buffer_index (wrk, &bi);
+      (void) tcp_get_free_buffer_index (wrk, &bi);
       ASSERT (bi != (u32) ~ 0);
       *b = vlib_get_buffer (vm, bi);
       data = tcp_init_buffer (vm, *b);
@@ -1374,6 +1417,55 @@ tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
   ASSERT (n_bytes > 0);
   ASSERT (((*b)->current_data + (*b)->current_length) <= bytes_per_buffer);
 
+  return n_bytes;
+}
+
+/**
+ * Build a retransmit segment
+ *
+ * @return the number of bytes in the segment or 0 if there's nothing to
+ *         retransmit
+ */
+static u32
+tcp_prepare_retransmit_segment (tcp_worker_ctx_t * wrk,
+				tcp_connection_t * tc, u32 offset,
+				u32 max_deq_bytes, vlib_buffer_t ** b)
+{
+  u32 start, available_bytes;
+  int n_bytes = 0;
+
+  ASSERT (tc->state >= TCP_STATE_ESTABLISHED);
+  ASSERT (max_deq_bytes != 0);
+
+  /*
+   * Make sure we can retransmit something
+   */
+  available_bytes = session_tx_fifo_max_dequeue (&tc->connection);
+  ASSERT (available_bytes >= offset);
+  available_bytes -= offset;
+  if (!available_bytes)
+    return 0;
+
+  max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes);
+  max_deq_bytes = clib_min (available_bytes, max_deq_bytes);
+
+  /* Start is beyond snd_congestion */
+  start = tc->snd_una + offset;
+  if (seq_geq (start, tc->snd_congestion))
+    goto done;
+
+  /* Don't overshoot snd_congestion */
+  if (seq_gt (start + max_deq_bytes, tc->snd_congestion))
+    {
+      max_deq_bytes = tc->snd_congestion - start;
+      if (max_deq_bytes == 0)
+	goto done;
+    }
+
+  n_bytes = tcp_prepare_segment (wrk, tc, offset, max_deq_bytes, b);
+  if (!n_bytes)
+    return 0;
+
   if (tcp_in_fastrecovery (tc))
     tc->snd_rxt_bytes += n_bytes;
 
@@ -1696,6 +1788,36 @@ tcp_retransmit_first_unacked (tcp_worker_ctx_t * wrk, tcp_connection_t * tc)
   return 0;
 }
 
+static int
+tcp_fast_retransmit_unsent (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
+			    u32 burst_size)
+{
+  u32 offset, n_segs = 0, n_written, bi;
+  vlib_main_t *vm = wrk->vm;
+  vlib_buffer_t *b = 0;
+
+  tc->snd_nxt = tc->snd_una_max;
+  offset = tc->snd_una_max - tc->snd_una;
+  while (n_segs < burst_size)
+    {
+      n_written = tcp_prepare_segment (wrk, tc, offset, tc->snd_mss, &b);
+      if (!n_written)
+	goto done;
+
+      bi = vlib_get_buffer_index (vm, b);
+      tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
+      offset += n_written;
+      n_segs += 1;
+    }
+
+done:
+  return n_segs;
+}
+
+#define scoreboard_rescue_rxt_valid(_sb, _tc)			\
+    (seq_geq (_sb->rescue_rxt, _tc->snd_una) 			\
+	&& seq_leq (_sb->rescue_rxt, _tc->snd_congestion))
+
 /**
  * Do fast retransmit with SACKs
  */
@@ -1703,55 +1825,54 @@ int
 tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
 			  u32 burst_size)
 {
+  u32 n_written = 0, offset, max_bytes, n_segs = 0, n_segs_now;
+  sack_scoreboard_hole_t *hole;
   vlib_main_t *vm = wrk->vm;
-  u32 n_written = 0, offset, max_bytes, n_segs = 0;
   vlib_buffer_t *b = 0;
-  sack_scoreboard_hole_t *hole;
   sack_scoreboard_t *sb;
   u32 bi, old_snd_nxt;
   int snd_space;
+  u32 max_deq;
   u8 snd_limited = 0, can_rescue = 0;
 
   ASSERT (tcp_in_fastrecovery (tc));
 
-  old_snd_nxt = tc->snd_nxt;
-  sb = &tc->sack_sb;
   snd_space = tcp_available_cc_snd_space (tc);
-  hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
-
   if (snd_space < tc->snd_mss)
     {
       tcp_program_fastretransmit (wrk, tc);
-      goto done;
+      return 0;
     }
 
   TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
+  old_snd_nxt = tc->snd_nxt;
+  sb = &tc->sack_sb;
+  hole = scoreboard_get_hole (sb, sb->cur_rxt_hole);
+
+  max_deq = session_tx_fifo_max_dequeue (&tc->connection);
+  max_deq -= tc->snd_una_max - tc->snd_una;
+
   while (snd_space > 0 && n_segs < burst_size)
     {
-      hole = scoreboard_next_rxt_hole (sb, hole,
-				       tcp_fastrecovery_sent_1_smss (tc),
-				       &can_rescue, &snd_limited);
+      hole = scoreboard_next_rxt_hole (sb, hole, max_deq, &can_rescue,
+				       &snd_limited);
       if (!hole)
 	{
-	  if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una)
-			       || seq_gt (sb->rescue_rxt,
-					  tc->snd_congestion)))
+	  if (max_deq)
 	    {
-	      if (tcp_fastrecovery_first (tc))
-		break;
-
-	      /* We tend to lose the first segment. Try re-resending
-	       * it but only once and after we've tried everything */
-	      hole = scoreboard_first_hole (sb);
-	      if (hole && hole->start == tc->snd_una)
-		{
-		  tcp_retransmit_first_unacked (wrk, tc);
-		  tcp_fastrecovery_first_on (tc);
-		  n_segs += 1;
-		}
-	      break;
+	      snd_space = clib_min (max_deq, snd_space);
+	      burst_size = clib_min (burst_size - n_segs,
+				     snd_space / tc->snd_mss);
+	      n_segs_now = tcp_fast_retransmit_unsent (wrk, tc, burst_size);
+	      if (max_deq > n_segs_now * tc->snd_mss)
+		tcp_program_fastretransmit (wrk, tc);
+	      n_segs += n_segs_now;
+	      goto done;
 	    }
 
+	  if (!can_rescue || scoreboard_rescue_rxt_valid (sb, tc))
+	    break;
+
 	  /* If rescue rxt undefined or less than snd_una then one segment of
 	   * up to SMSS octets that MUST include the highest outstanding
 	   * unSACKed sequence number SHOULD be returned, and RescueRxt set to
@@ -1778,19 +1899,21 @@ tcp_fast_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
       max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes;
       if (max_bytes == 0)
 	break;
+
       offset = sb->high_rxt - tc->snd_una;
       tc->snd_nxt = sb->high_rxt;
       n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, max_bytes,
 						  &b);
+      ASSERT (n_written <= snd_space);
 
       /* Nothing left to retransmit */
       if (n_written == 0)
 	break;
 
       bi = vlib_get_buffer_index (vm, b);
-      sb->high_rxt += n_written;
       tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
-      ASSERT (n_written <= snd_space);
+
+      sb->high_rxt += n_written;
       snd_space -= n_written;
       n_segs += 1;
     }
@@ -1811,24 +1934,26 @@ int
 tcp_fast_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
 			     u32 burst_size)
 {
-  u32 n_written = 0, offset = 0, bi, old_snd_nxt;
+  u32 n_written = 0, offset = 0, bi, old_snd_nxt, max_deq, n_segs_now;
   vlib_main_t *vm = wrk->vm;
   int snd_space, n_segs = 0;
   vlib_buffer_t *b;
 
   ASSERT (tcp_in_fastrecovery (tc));
   TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0);
-
-  /* Start resending from first un-acked segment */
   old_snd_nxt = tc->snd_nxt;
-  tc->snd_nxt = tc->snd_una;
-  snd_space = tcp_available_cc_snd_space (tc);
 
+  if (!tcp_fastrecovery_first (tc))
+    goto send_unsent;
+
+  /* RFC 6582: [If a partial ack], retransmit the first unacknowledged
+   * segment. */
+  snd_space = tc->sack_sb.last_bytes_delivered;
+  tc->snd_nxt = tc->snd_una;
   while (snd_space > 0 && n_segs < burst_size)
     {
-      offset += n_written;
-      n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, snd_space,
-						  &b);
+      n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
+						  tc->snd_mss, &b);
 
       /* Nothing left to retransmit */
       if (n_written == 0)
@@ -1837,16 +1962,37 @@ tcp_fast_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
       bi = vlib_get_buffer_index (vm, b);
       tcp_enqueue_to_output (wrk, b, bi, tc->c_is_ip4);
       snd_space -= n_written;
+      offset += n_written;
       n_segs += 1;
     }
 
-  /* More data to resend */
-  if (seq_lt (tc->snd_nxt, tc->snd_congestion))
-    tcp_program_fastretransmit (wrk, tc);
+  if (n_segs == burst_size)
+    goto done;
+
+send_unsent:
+
+  /* RFC 6582: Send a new segment if permitted by the new value of cwnd. */
+  snd_space = tcp_available_cc_snd_space (tc);
+  if (snd_space < tc->snd_mss || tc->snd_mss == 0)
+    goto done;
+
+  max_deq = session_tx_fifo_max_dequeue (&tc->connection);
+  max_deq -= tc->snd_una_max - tc->snd_una;
+  if (max_deq)
+    {
+      snd_space = clib_min (max_deq, snd_space);
+      burst_size = clib_min (burst_size - n_segs, snd_space / tc->snd_mss);
+      n_segs_now = tcp_fast_retransmit_unsent (wrk, tc, burst_size);
+      if (max_deq > n_segs_now * tc->snd_mss)
+	tcp_program_fastretransmit (wrk, tc);
+      n_segs += n_segs_now;
+    }
 
-  /* Restore snd_nxt. If window allows, send 1 SMSS of new data */
+  /* Restore snd_nxt */
   tc->snd_nxt = old_snd_nxt;
 
+done:
+  tcp_fastrecovery_first_off (tc);
   return n_segs;
 }
 
@@ -1863,13 +2009,6 @@ tcp_fast_retransmit (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
     return tcp_fast_retransmit_no_sack (wrk, tc, burst_size);
 }
 
-static u32
-tcp_session_has_ooo_data (tcp_connection_t * tc)
-{
-  stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index);
-  return svm_fifo_has_ooo_data (s->server_rx_fifo);
-}
-
 static void
 tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
 			      u16 * next0, u32 * error0)
@@ -1974,25 +2113,6 @@ tcp_output_handle_packet (tcp_connection_t * tc0, vlib_buffer_t * b0,
 	tcp_output_handle_link_local (tc0, b0, next0, error0);
     }
 
-  /* Filter out DUPACKs if there are no OOO segments left */
-  if (PREDICT_FALSE (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK))
-    {
-      /* N.B. Should not filter burst of dupacks. Two issues:
-       * 1) dupacks open cwnd on remote peer when congested
-       * 2) acks leaving should have the latest rcv_wnd since the
-       *    burst may have eaten up all of it, so only the old ones
-       *     could be filtered.
-       */
-      if (!tcp_session_has_ooo_data (tc0))
-	{
-	  *error0 = TCP_ERROR_FILTERED_DUPACKS;
-	  *next0 = TCP_OUTPUT_NEXT_DROP;
-	  return;
-	}
-    }
-
-  /* Stop DELACK timer and fix flags */
-  tc0->flags &= ~(TCP_CONN_SNDACK);
   if (!TCP_ALWAYS_ACK)
     tcp_timer_reset (tc0, TCP_TIMER_DELACK);
 }