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-rw-r--r--src/net/tcp.c33
1 files changed, 25 insertions, 8 deletions
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 1c48769..987cb63 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -16,6 +16,7 @@
#include <ipxe/uri.h>
#include <ipxe/netdevice.h>
#include <ipxe/profile.h>
+#include <ipxe/process.h>
#include <ipxe/tcpip.h>
#include <ipxe/tcp.h>
@@ -107,6 +108,8 @@ struct tcp_connection {
struct list_head tx_queue;
/** Receive queue */
struct list_head rx_queue;
+ /** Transmission process */
+ struct process process;
/** Retransmission timer */
struct retry_timer timer;
/** Shutdown (TIME_WAIT) timer */
@@ -166,6 +169,7 @@ static struct profiler tcp_rx_profiler __profiler = { .name = "tcp.rx" };
static struct profiler tcp_xfer_profiler __profiler = { .name = "tcp.xfer" };
/* Forward declarations */
+static struct process_descriptor tcp_process_desc;
static struct interface_descriptor tcp_xfer_desc;
static void tcp_expired ( struct retry_timer *timer, int over );
static void tcp_wait_expired ( struct retry_timer *timer, int over );
@@ -273,6 +277,7 @@ static int tcp_open ( struct interface *xfer, struct sockaddr *peer,
DBGC ( tcp, "TCP %p allocated\n", tcp );
ref_init ( &tcp->refcnt, NULL );
intf_init ( &tcp->xfer, &tcp_xfer_desc, &tcp->refcnt );
+ process_init_stopped ( &tcp->process, &tcp_process_desc, &tcp->refcnt );
timer_init ( &tcp->timer, tcp_expired, &tcp->refcnt );
timer_init ( &tcp->wait, tcp_wait_expired, &tcp->refcnt );
tcp->prev_tcp_state = TCP_CLOSED;
@@ -369,6 +374,7 @@ static void tcp_close ( struct tcp_connection *tcp, int rc ) {
pending_put ( &tcp->pending_flags );
/* Remove from list and drop reference */
+ process_del ( &tcp->process );
stop_timer ( &tcp->timer );
stop_timer ( &tcp->wait );
list_del ( &tcp->list );
@@ -497,7 +503,7 @@ static size_t tcp_process_tx_queue ( struct tcp_connection *tcp, size_t max_len,
* will have been started if necessary, and so the stack will
* eventually attempt to retransmit the failed packet.
*/
-static int tcp_xmit ( struct tcp_connection *tcp ) {
+static void tcp_xmit ( struct tcp_connection *tcp ) {
struct io_buffer *iobuf;
struct tcp_header *tcphdr;
struct tcp_mss_option *mssopt;
@@ -517,7 +523,7 @@ static int tcp_xmit ( struct tcp_connection *tcp ) {
/* If retransmission timer is already running, do nothing */
if ( timer_running ( &tcp->timer ) )
- return 0;
+ return;
/* Calculate both the actual (payload) and sequence space
* lengths that we wish to transmit.
@@ -537,7 +543,7 @@ static int tcp_xmit ( struct tcp_connection *tcp ) {
/* If we have nothing to transmit, stop now */
if ( ( seq_len == 0 ) && ! ( tcp->flags & TCP_ACK_PENDING ) )
- return 0;
+ return;
/* If we are transmitting anything that requires
* acknowledgement (i.e. consumes sequence space), start the
@@ -553,7 +559,7 @@ static int tcp_xmit ( struct tcp_connection *tcp ) {
DBGC ( tcp, "TCP %p could not allocate iobuf for %08x..%08x "
"%08x\n", tcp, tcp->snd_seq, ( tcp->snd_seq + seq_len ),
tcp->rcv_ack );
- return -ENOMEM;
+ return;
}
iob_reserve ( iobuf, TCP_MAX_HEADER_LEN );
@@ -620,16 +626,19 @@ static int tcp_xmit ( struct tcp_connection *tcp ) {
DBGC ( tcp, "TCP %p could not transmit %08x..%08x %08x: %s\n",
tcp, tcp->snd_seq, ( tcp->snd_seq + tcp->snd_sent ),
tcp->rcv_ack, strerror ( rc ) );
- return rc;
+ return;
}
/* Clear ACK-pending flag */
tcp->flags &= ~TCP_ACK_PENDING;
profile_stop ( &tcp_tx_profiler );
- return 0;
}
+/** TCP process descriptor */
+static struct process_descriptor tcp_process_desc =
+ PROC_DESC_ONCE ( struct tcp_connection, process, tcp_xmit );
+
/**
* Retransmission timer expired
*
@@ -1272,8 +1281,16 @@ static int tcp_rx ( struct io_buffer *iobuf,
/* Dump out any state change as a result of the received packet */
tcp_dump_state ( tcp );
- /* Send out any pending data */
- tcp_xmit ( tcp );
+ /* Schedule transmission of ACK (and any pending data). If we
+ * have received any out-of-order packets (i.e. if the receive
+ * queue remains non-empty after processing) then send the ACK
+ * immediately in order to trigger Fast Retransmission.
+ */
+ if ( list_empty ( &tcp->rx_queue ) ) {
+ process_add ( &tcp->process );
+ } else {
+ tcp_xmit ( tcp );
+ }
/* If this packet was the last we expect to receive, set up
* timer to expire and cause the connection to be freed.