[tcp] Mark any unacknowledged transmission as a pending operation

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/net/tcp.c b/src/net/tcp.c
index b15339153122de488301f3ab047e9dd9e68e0a20..c6bb4a6625a257811c5dcbe74826b802818056b5 100644 (file)
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -10,6 +10,7 @@
 #include <ipxe/init.h>
 #include <ipxe/retry.h>
 #include <ipxe/refcnt.h>
+#include <ipxe/pending.h>
 #include <ipxe/xfer.h>
 #include <ipxe/open.h>
 #include <ipxe/uri.h>
@@ -95,6 +96,11 @@ struct tcp_connection {
        struct retry_timer timer;
        /** Shutdown (TIME_WAIT) timer */
        struct retry_timer wait;
+
+       /** Pending operations for SYN and FIN */
+       struct pending_operation pending_flags;
+       /** Pending operations for transmit queue */
+       struct pending_operation pending_data;
 };
 
 /** TCP flags */
@@ -291,6 +297,9 @@ static int tcp_open ( struct interface *xfer, struct sockaddr *peer,
        /* Start timer to initiate SYN */
        start_timer_nodelay ( &tcp->timer );
 
+       /* Add a pending operation for the SYN */
+       pending_get ( &tcp->pending_flags );
+
        /* Attach parent interface, transfer reference to connection
         * list and return
         */
@@ -340,7 +349,13 @@ static void tcp_close ( struct tcp_connection *tcp, int rc ) {
                list_for_each_entry_safe ( iobuf, tmp, &tcp->tx_queue, list ) {
                        list_del ( &iobuf->list );
                        free_iob ( iobuf );
+                       pending_put ( &tcp->pending_data );
                }
+               assert ( ! is_pending ( &tcp->pending_data ) );
+
+               /* Remove pending operations for SYN and FIN, if applicable */
+               pending_put ( &tcp->pending_flags );
+               pending_put ( &tcp->pending_flags );
 
                /* Remove from list and drop reference */
                stop_timer ( &tcp->timer );
@@ -359,9 +374,14 @@ static void tcp_close ( struct tcp_connection *tcp, int rc ) {
                tcp_rx_ack ( tcp, ( tcp->snd_seq + 1 ), 0 );
 
        /* If we have no data remaining to send, start sending FIN */
-       if ( list_empty ( &tcp->tx_queue ) ) {
+       if ( list_empty ( &tcp->tx_queue ) &&
+            ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) {
+
                tcp->tcp_state |= TCP_STATE_SENT ( TCP_FIN );
                tcp_dump_state ( tcp );
+
+               /* Add a pending operation for the FIN */
+               pending_get ( &tcp->pending_flags );
        }
 }
 
@@ -446,6 +466,7 @@ static size_t tcp_process_tx_queue ( struct tcp_connection *tcp, size_t max_len,
                        if ( ! iob_len ( iobuf ) ) {
                                list_del ( &iobuf->list );
                                free_iob ( iobuf );
+                               pending_put ( &tcp->pending_data );
                        }
                }
                len += frag_len;
@@ -869,8 +890,10 @@ static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack,
        len = ack_len;
        acked_flags = ( TCP_FLAGS_SENDING ( tcp->tcp_state ) &
                        ( TCP_SYN | TCP_FIN ) );
-       if ( acked_flags )
+       if ( acked_flags ) {
                len--;
+               pending_put ( &tcp->pending_flags );
+       }
 
        /* Update SEQ and sent counters, and window size */
        tcp->snd_seq = ack;
@@ -885,8 +908,12 @@ static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack,
                tcp->tcp_state |= TCP_STATE_ACKED ( acked_flags );
 
        /* Start sending FIN if we've had all possible data ACKed */
-       if ( list_empty ( &tcp->tx_queue ) && ( tcp->flags & TCP_XFER_CLOSED ) )
+       if ( list_empty ( &tcp->tx_queue ) &&
+            ( tcp->flags & TCP_XFER_CLOSED ) &&
+            ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) {
                tcp->tcp_state |= TCP_STATE_SENT ( TCP_FIN );
+               pending_get ( &tcp->pending_flags );
+       }
 
        return 0;
 }
@@ -1320,6 +1347,9 @@ static int tcp_xfer_deliver ( struct tcp_connection *tcp,
        /* Enqueue packet */
        list_add_tail ( &iobuf->list, &tcp->tx_queue );
 
+       /* Each enqueued packet is a pending operation */
+       pending_get ( &tcp->pending_data );
+
        /* Transmit data, if possible */
        tcp_xmit ( tcp );