tcp: Request retransmission with updated sequence also on partial write to socket

If we couldn't write the whole batch of received packets to the socket,
and we have missing segments, we still need to request their
retransmission right away, otherwise it will take ages for the guest to
figure out we're missing them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 8 insertions, 11 deletions

diff --git a/tcp.c b/tcp.c
index e58658e..4d2d485 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2088,13 +2088,8 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
 		return;
 	}
 
-	if (keep != -1) {
-		tcp_send_to_tap(c, conn, ACK, NULL, 0);
-		tcp_send_to_tap(c, conn, ACK, NULL, 0);
-	}
-
 	if (!iov_i)
-		goto fin_check;
+		goto out;
 
 	mh.msg_iovlen = iov_i;
 eintr:
@@ -2114,14 +2109,16 @@ eintr:
 	if (len < (seq_from_tap - conn->seq_from_tap)) {
 		conn->seq_from_tap += len;
 		tcp_send_to_tap(c, conn, ZERO_WINDOW, NULL, 0);
-		return;
+	} else {
+		conn->seq_from_tap += len;
 	}
 
-	conn->seq_from_tap += len;
-
-fin_check:
-	if (keep != -1)
+out:
+	if (keep != -1) {
+		tcp_send_to_tap(c, conn, ACK, NULL, 0);
+		tcp_send_to_tap(c, conn, ACK, NULL, 0);
 		return;
+	}
 
 	if (ack) {
 		if (conn->state == ESTABLISHED_SOCK_FIN_SENT &&