First off, don't close connections half-closed by the guest before
our own FIN is acknowledged by the guest itself.
That is, after we receive a FIN from the guest (TAP_FIN_RCVD), if we
don't have any data left to send from the socket (SOCK_FIN_RCVD, or
EPOLLHUP), we send a FIN segment to the guest (TAP_FIN_SENT), but we
need to actually have it acknowledged (and have no pending
retransmissions) before we can close the connection: check for
TAP_FIN_ACKED, first.
Then, if we set TAP_FIN_SENT, and we receive an ACK segment from the
guest, set TAP_FIN_ACKED. This was entirely missing for the
TAP_FIN_RCVD case, and as we fix the problem described above, this
becomes relevant as well.
Signed-off-by: Stefano Brivio
Reviewed-by: David Gibson
---
tcp.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/tcp.c b/tcp.c
index 11c9c84..fccea35 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2090,9 +2090,14 @@ int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
tcp_tap_window_update(c, conn, ntohs(th->window));
tcp_data_from_sock(c, conn);
- if (conn->events & SOCK_FIN_RCVD &&
- conn->seq_ack_from_tap == conn->seq_to_tap)
- conn_event(c, conn, CLOSED);
+ if (conn->seq_ack_from_tap == conn->seq_to_tap) {
+ if (th->ack && conn->events & TAP_FIN_SENT)
+ conn_event(c, conn, TAP_FIN_ACKED);
+
+ if (conn->events & SOCK_FIN_RCVD &&
+ conn->events & TAP_FIN_ACKED)
+ conn_event(c, conn, CLOSED);
+ }
return 1;
}
@@ -2372,7 +2377,7 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
return;
}
- if ((conn->events & TAP_FIN_SENT) && (events & EPOLLHUP)) {
+ if ((conn->events & TAP_FIN_ACKED) && (events & EPOLLHUP)) {
conn_event(c, conn, CLOSED);
return;
}
--
2.43.0