tcp: fix retransmit with no sacks

Type: fix

Change-Id: I6f7df0d358f57f7feadb9b7a3fcffb99558b2af8
Signed-off-by: Florin Coras <fcoras@cisco.com>
(cherry picked from commit bf1f8b7f288c29bfcc128b1d09eae1c1eac2b7cc)

3 files changed, 18 insertions, 10 deletions

diff --git a/src/vnet/tcp/tcp.h b/src/vnet/tcp/tcp.h
index be8d38770d5..8530ba499fc 100644
--- a/src/vnet/tcp/tcp.h
+++ b/src/vnet/tcp/tcp.h
@@ -885,7 +885,8 @@ tcp_bytes_out (const tcp_connection_t * tc)
   if (tcp_opts_sack_permitted (&tc->rcv_opts))
     return tc->sack_sb.sacked_bytes + tc->sack_sb.lost_bytes;
   else
-    return tc->rcv_dupacks * tc->snd_mss;
+    return clib_min (tc->rcv_dupacks * tc->snd_mss,
+		     tc->snd_nxt - tc->snd_una);
 }
 
 /**
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 83769465525..f838d59e30a 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1485,9 +1485,12 @@ tcp_cc_handle_event (tcp_connection_t * tc, tcp_rate_sample_t * rs,
       tc->rxt_delivered = clib_max (tc->rxt_delivered + tc->bytes_acked,
 				    tc->snd_rxt_bytes);
       if (is_dack)
-	tc->prr_delivered += 1;
+	tc->prr_delivered += clib_min (tc->snd_mss,
+				       tc->snd_nxt - tc->snd_una);
       else
-	tc->prr_delivered += tc->bytes_acked - tc->snd_mss * tc->rcv_dupacks;
+	tc->prr_delivered += tc->bytes_acked - clib_min (tc->bytes_acked,
+							 tc->snd_mss *
+							 tc->rcv_dupacks);
 
       /* If partial ack, assume that the first un-acked segment was lost */
       if (tc->bytes_acked || tc->rcv_dupacks == TCP_DUPACK_THRESHOLD)
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 2437b7bf28f..620d19b21c3 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1960,8 +1960,8 @@ tcp_retransmit_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
       && tc->rxt_head != tc->snd_una
       && tcp_retransmit_should_retry_head (tc, sb))
     {
-      n_written = tcp_prepare_retransmit_segment (wrk, tc, 0, tc->snd_mss,
-						  &b);
+      max_bytes = clib_min (tc->snd_mss, tc->snd_congestion - tc->snd_una);
+      n_written = tcp_prepare_retransmit_segment (wrk, tc, 0, max_bytes, &b);
       if (!n_written)
 	{
 	  tcp_program_retransmit (tc);
@@ -2087,7 +2087,7 @@ static int
 tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
 			u32 burst_size)
 {
-  u32 n_written = 0, offset = 0, bi, max_deq, n_segs_now;
+  u32 n_written = 0, offset = 0, bi, max_deq, n_segs_now, max_bytes;
   u32 burst_bytes, sent_bytes;
   vlib_main_t *vm = wrk->vm;
   int snd_space, n_segs = 0;
@@ -2095,7 +2095,7 @@ tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
   vlib_buffer_t *b;
   u64 time_now;
 
-  ASSERT (tcp_in_fastrecovery (tc));
+  ASSERT (tcp_in_cong_recovery (tc));
   TCP_EVT (TCP_EVT_CC_EVT, tc, 0);
 
   time_now = wrk->vm->clib_time.last_cpu_time;
@@ -2118,8 +2118,12 @@ tcp_retransmit_no_sack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc,
    * segment. */
   while (snd_space > 0 && n_segs < burst_size)
     {
-      n_written = tcp_prepare_retransmit_segment (wrk, tc, offset,
-						  tc->snd_mss, &b);
+      max_bytes = clib_min (tc->snd_mss,
+			    tc->snd_congestion - tc->snd_una - offset);
+      if (!max_bytes)
+	break;
+      n_written = tcp_prepare_retransmit_segment (wrk, tc, offset, max_bytes,
+						  &b);
 
       /* Nothing left to retransmit */
       if (n_written == 0)
@@ -2148,7 +2152,7 @@ send_unsent:
       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_transmit_unsent (wrk, tc, burst_size);
-      if (max_deq > n_segs_now * tc->snd_mss)
+      if (n_segs_now && max_deq > n_segs_now * tc->snd_mss)
 	tcp_program_retransmit (tc);
       n_segs += n_segs_now;
     }