[ipxe-devel] [PATCH 3/4] [tcp] Cleanup tcp_close()
Guo-Fu Tseng
cooldavid at cooldavid.org
Fri Jul 30 12:40:37 UTC 2010
From: Guo-Fu Tseng <cooldavid at cooldavid.org>
The complexity of tcp_close() makes the TCP closing control
hard to maintain.
This patch try to solve it by separating tcp_terminate() and
tcp_dataxfer_close() from tcp_close().
Use tcp_terminate() to immediately free all tcp resources, and
close data transfer interface by calling tcp_dataxfer_close().
tcp_close() now simply bing TCP connection to closing state.
Which makes it safe to call in tcp_rx_fin().
tcp_dataxfer_close() is separated due to early close timing of
tcp_xfer_close() which is called by upper-layer to indicate no
more data to send or receive.
Signed-off-by: Guo-Fu Tseng <cooldavid at cooldavid.org>
---
src/net/tcp.c | 104 +++++++++++++++++++++++++++++---------------------------
1 files changed, 54 insertions(+), 50 deletions(-)
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 94277c9..4318004 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -298,52 +298,63 @@ static int tcp_open ( struct interface *xfer, struct sockaddr *peer,
}
/**
- * Close TCP connection
+ * Close data transfer interface
*
* @v tcp TCP connection
* @v rc Reason for close
*
- * Closes the data transfer interface. If the TCP state machine is in
- * a suitable state, the connection will be deleted.
+ * Closes the data transfer interface.
*/
-static void tcp_close ( struct tcp_connection *tcp, int rc ) {
- struct io_buffer *iobuf;
- struct io_buffer *tmp;
-
- /* Close data transfer interface */
+static void tcp_dataxfer_close ( struct tcp_connection *tcp, int rc ) {
intf_shutdown ( &tcp->xfer, rc );
tcp->flags |= TCP_XFER_CLOSED;
+}
- /* If we are in CLOSED, or have otherwise not yet received a
- * SYN (i.e. we are in LISTEN or SYN_SENT), just delete the
- * connection.
- */
- if ( ! ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) ) {
+/**
+ * Terminate TCP connection and free all resources
+ *
+ * @v tcp TCP connection
+ * @v rc Reason for close
+ *
+ * Closes the data transfer interface, and free all resources of current TCP
+ * connection.
+ */
+static void tcp_terminate ( struct tcp_connection *tcp, int rc ) {
+ struct io_buffer *iobuf;
+ struct io_buffer *tmp;
- /* Transition to CLOSED for the sake of debugging messages */
- tcp->tcp_state = TCP_CLOSED;
- tcp_dump_state ( tcp );
+ /* Close data transfer interface */
+ tcp_dataxfer_close(tcp, rc);
- /* Free any unprocessed I/O buffers */
- list_for_each_entry_safe ( iobuf, tmp, &tcp->rx_queue, list ) {
- list_del ( &iobuf->list );
- free_iob ( iobuf );
- }
+ /* Transition to CLOSED for the sake of debugging messages */
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
- /* Free any unsent I/O buffers */
- list_for_each_entry_safe ( iobuf, tmp, &tcp->tx_queue, list ) {
- list_del ( &iobuf->list );
- free_iob ( iobuf );
- }
+ /* Free any unprocessed I/O buffers */
+ list_for_each_entry_safe ( iobuf, tmp, &tcp->rx_queue, list ) {
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
+ }
- /* Remove from list and drop reference */
- stop_timer ( &tcp->timer );
- list_del ( &tcp->list );
- ref_put ( &tcp->refcnt );
- DBGC ( tcp, "TCP %p connection deleted\n", tcp );
- return;
+ /* Free any unsent I/O buffers */
+ list_for_each_entry_safe ( iobuf, tmp, &tcp->tx_queue, list ) {
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
}
+ /* Remove from list and drop reference */
+ stop_timer ( &tcp->timer );
+ list_del ( &tcp->list );
+ ref_put ( &tcp->refcnt );
+ DBGC ( tcp, "TCP %p connection deleted\n", tcp );
+}
+
+/**
+ * Bring TCP connection to closing state
+ *
+ * @v tcp TCP connection
+ */
+static void tcp_close ( struct tcp_connection *tcp ) {
/* If we have not had our SYN acknowledged (i.e. we are in
* SYN_RCVD), pretend that it has been acknowledged so that we
* can send a FIN without breaking things.
@@ -586,9 +597,7 @@ static void tcp_expired ( struct retry_timer *timer, int over ) {
/* If we have finally timed out and given up,
* terminate the connection
*/
- tcp->tcp_state = TCP_CLOSED;
- tcp_dump_state ( tcp );
- tcp_close ( tcp, -ETIMEDOUT );
+ tcp_terminate ( tcp, -ETIMEDOUT );
} else {
/* Otherwise, retransmit the packet */
tcp_xmit ( tcp );
@@ -611,9 +620,7 @@ static void tcp_wait_expired ( struct retry_timer *timer, int over __unused ) {
tcp_state ( tcp->tcp_state ), tcp->snd_seq,
( tcp->snd_seq + tcp->snd_sent ), tcp->rcv_ack );
- tcp->tcp_state = TCP_CLOSED;
- tcp_dump_state ( tcp );
- tcp_close ( tcp, 0 );
+ tcp_terminate ( tcp, 0 );
}
/**
@@ -910,6 +917,9 @@ static int tcp_rx_fin ( struct tcp_connection *tcp, uint32_t seq ) {
DBGC ( tcp, "TCP %p passive closing.\n", tcp );
}
+ /* Bring TCP connection to closing state */
+ tcp_close ( tcp );
+
return 0;
}
@@ -936,9 +946,7 @@ static int tcp_rx_rst ( struct tcp_connection *tcp, uint32_t seq ) {
}
/* Abort connection */
- tcp->tcp_state = TCP_CLOSED;
- tcp_dump_state ( tcp );
- tcp_close ( tcp, -ECONNRESET );
+ tcp_terminate ( tcp, -ECONNRESET );
DBGC ( tcp, "TCP %p connection reset by peer\n", tcp );
return -ECONNRESET;
@@ -1048,11 +1056,6 @@ static void tcp_process_rx_queue ( struct tcp_connection *tcp ) {
seq, strerror ( rc ) );
}
}
-
- if ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_FIN ) ) {
- /* Close connection */
- tcp_close ( tcp, 0 );
- }
}
/**
@@ -1187,9 +1190,7 @@ static int tcp_rx ( struct io_buffer *iobuf,
* Set up timer to expire and cause the connection to be freed.
*/
if ( tcp->tcp_state == TCP_PASV_CLOSED ) {
- tcp->tcp_state = TCP_CLOSED;
- tcp_dump_state ( tcp );
- tcp_close ( tcp, 0 );
+ tcp_terminate ( tcp, 0 );
} else if ( TCP_CLOSED_GRACEFULLY ( tcp->tcp_state ) ) {
stop_timer ( &tcp->wait );
start_timer_fixed ( &tcp->wait, ( 2 * TCP_MSL ) );
@@ -1254,7 +1255,10 @@ struct cache_discarder tcp_cache_discarder __cache_discarder = {
static void tcp_xfer_close ( struct tcp_connection *tcp, int rc ) {
/* Close data transfer interface */
- tcp_close ( tcp, rc );
+ tcp_dataxfer_close ( tcp, rc );
+
+ /* Bring TCP connection to closing state */
+ tcp_close ( tcp );
/* Transmit FIN, if possible */
tcp_xmit ( tcp );
--
1.7.1
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