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-rw-r--r--src/core/downloader.c1
-rw-r--r--src/core/hw.c3
-rw-r--r--src/core/posix_io.c1
-rw-r--r--src/core/resolv.c17
-rw-r--r--src/core/xfer.c43
-rw-r--r--src/include/gpxe/xfer.h33
-rw-r--r--src/interface/pxe/pxe_udp.c1
-rw-r--r--src/net/tcp.c28
-rw-r--r--src/net/tcp/ftp.c3
-rw-r--r--src/net/tcp/http.c4
-rw-r--r--src/net/udp.c1
-rw-r--r--src/net/udp/dhcp.c1
-rw-r--r--src/net/udp/dns.c1
-rw-r--r--src/net/udp/tftp.c2
14 files changed, 94 insertions, 45 deletions
diff --git a/src/core/downloader.c b/src/core/downloader.c
index 4a74589f..3726c6e1 100644
--- a/src/core/downloader.c
+++ b/src/core/downloader.c
@@ -228,6 +228,7 @@ static struct xfer_interface_operations downloader_xfer_operations = {
.close = downloader_xfer_close,
.vredirect = xfer_vopen,
.seek = downloader_xfer_seek,
+ .window = unlimited_xfer_window,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = downloader_xfer_deliver_raw,
};
diff --git a/src/core/hw.c b/src/core/hw.c
index 2cb912b1..3502dbfb 100644
--- a/src/core/hw.c
+++ b/src/core/hw.c
@@ -37,6 +37,7 @@ static struct xfer_interface_operations hw_xfer_operations = {
.close = hw_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
};
@@ -45,7 +46,7 @@ static void hw_step ( struct process *process ) {
struct hw *hw = container_of ( process, struct hw, process );
int rc;
- if ( xfer_ready ( &hw->xfer ) == 0 ) {
+ if ( xfer_window ( &hw->xfer ) ) {
rc = xfer_deliver_raw ( &hw->xfer, hw_msg, sizeof ( hw_msg ) );
hw_finished ( hw, rc );
}
diff --git a/src/core/posix_io.c b/src/core/posix_io.c
index 03d440a6..21f818bf 100644
--- a/src/core/posix_io.c
+++ b/src/core/posix_io.c
@@ -160,6 +160,7 @@ static struct xfer_interface_operations posix_file_xfer_operations = {
.close = posix_file_xfer_close,
.vredirect = xfer_vopen,
.seek = posix_file_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = posix_file_xfer_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
diff --git a/src/core/resolv.c b/src/core/resolv.c
index 7ca62cd8..5c25ddb1 100644
--- a/src/core/resolv.c
+++ b/src/core/resolv.c
@@ -308,25 +308,12 @@ struct named_socket {
int have_local;
};
-/**
- * Handle seek() event
- *
- * @v xfer Data transfer interface
- * @v offset Offset to new position
- * @v whence Basis for new position
- * @ret rc Return status code
- */
-static int resolv_xfer_seek ( struct xfer_interface *xfer __unused,
- off_t offset __unused, int whence __unused ) {
- /* Never ready to accept data */
- return -EAGAIN;
-}
-
/** Named socket opener data transfer interface operations */
static struct xfer_interface_operations named_xfer_ops = {
.close = ignore_xfer_close,
.vredirect = ignore_xfer_vredirect,
- .seek = resolv_xfer_seek,
+ .seek = ignore_xfer_seek,
+ .window = no_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
diff --git a/src/core/xfer.c b/src/core/xfer.c
index 3e55ebaf..3e6b7eb6 100644
--- a/src/core/xfer.c
+++ b/src/core/xfer.c
@@ -111,6 +111,22 @@ int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
}
/**
+ * Check flow control window
+ *
+ * @v xfer Data transfer interface
+ * @ret len Length of window
+ */
+size_t xfer_window ( struct xfer_interface *xfer ) {
+ struct xfer_interface *dest = xfer_get_dest ( xfer );
+ size_t len;
+
+ len = dest->op->window ( dest );
+
+ xfer_put ( dest );
+ return len;
+}
+
+/**
* Test to see if interface is ready to accept data
*
* @v xfer Data transfer interface
@@ -298,6 +314,32 @@ int ignore_xfer_seek ( struct xfer_interface *xfer __unused,
}
/**
+ * Unlimited flow control window
+ *
+ * @v xfer Data transfer interface
+ * @ret len Length of window
+ *
+ * This handler indicates that the interface is always ready to accept
+ * data.
+ */
+size_t unlimited_xfer_window ( struct xfer_interface *xfer __unused ) {
+ return ~( ( size_t ) 0 );
+}
+
+/**
+ * No flow control window
+ *
+ * @v xfer Data transfer interface
+ * @ret len Length of window
+ *
+ * This handler indicates that the interface is never ready to accept
+ * data.
+ */
+size_t no_xfer_window ( struct xfer_interface *xfer __unused ) {
+ return 0;
+}
+
+/**
* Allocate I/O buffer
*
* @v xfer Data transfer interface
@@ -374,6 +416,7 @@ struct xfer_interface_operations null_xfer_ops = {
.close = ignore_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
diff --git a/src/include/gpxe/xfer.h b/src/include/gpxe/xfer.h
index edf553f7..68c1169e 100644
--- a/src/include/gpxe/xfer.h
+++ b/src/include/gpxe/xfer.h
@@ -39,13 +39,26 @@ struct xfer_interface_operations {
* @v whence Basis for new position
* @ret rc Return status code
*
- * @c whence must be one of @c SEEK_SET or @c SEEK_CUR. A
- * successful return indicates that the interface is ready to
- * immediately accept datagrams; return -EAGAIN if this is not
- * the case.
+ * @c whence must be one of @c SEEK_SET or @c SEEK_CUR.
*/
int ( * seek ) ( struct xfer_interface *xfer, off_t offset,
int whence );
+ /** Check flow control window
+ *
+ * @v xfer Data transfer interface
+ * @ret len Length of window
+ *
+ * Flow control is regarded as advisory but not mandatory.
+ * Users who have control over their own rate of data
+ * generation should perform a flow control check before
+ * generating new data. Users who have no control (such as
+ * NIC drivers or filter layers) are not obliged to check.
+ *
+ * Data transfer interfaces must be prepared to accept
+ * datagrams even if they are advertising a window of zero
+ * bytes.
+ */
+ size_t ( * window ) ( struct xfer_interface *xfer );
/** Allocate I/O buffer
*
* @v xfer Data transfer interface
@@ -64,10 +77,6 @@ struct xfer_interface_operations {
* A data transfer interface that wishes to support only raw
* data delivery should set this method to
* xfer_deliver_as_raw().
- *
- * Interfaces may not temporarily refuse to accept data by
- * returning -EAGAIN; such a response may be treated as a
- * fatal error.
*/
int ( * deliver_iob ) ( struct xfer_interface *xfer,
struct io_buffer *iobuf,
@@ -82,10 +91,6 @@ struct xfer_interface_operations {
* A data transfer interface that wishes to support only I/O
* buffer delivery should set this method to
* xfer_deliver_as_iob().
- *
- * Interfaces may not temporarily refuse to accept data by
- * returning -EAGAIN; such a response may be treated as a
- * fatal error.
*/
int ( * deliver_raw ) ( struct xfer_interface *xfer,
const void *data, size_t len );
@@ -137,7 +142,7 @@ extern int xfer_vredirect ( struct xfer_interface *xfer, int type,
va_list args );
extern int xfer_redirect ( struct xfer_interface *xfer, int type, ... );
extern int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence );
-extern int xfer_ready ( struct xfer_interface *xfer );
+extern size_t xfer_window ( struct xfer_interface *xfer );
extern struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer,
size_t len );
extern int xfer_deliver_iob ( struct xfer_interface *xfer,
@@ -157,6 +162,8 @@ extern int ignore_xfer_vredirect ( struct xfer_interface *xfer,
int type, va_list args );
extern int ignore_xfer_seek ( struct xfer_interface *xfer, off_t offset,
int whence );
+extern size_t unlimited_xfer_window ( struct xfer_interface *xfer );
+extern size_t no_xfer_window ( struct xfer_interface *xfer );
extern struct io_buffer * default_xfer_alloc_iob ( struct xfer_interface *xfer,
size_t len );
extern int xfer_deliver_as_raw ( struct xfer_interface *xfer,
diff --git a/src/interface/pxe/pxe_udp.c b/src/interface/pxe/pxe_udp.c
index 153d758c..745366f2 100644
--- a/src/interface/pxe/pxe_udp.c
+++ b/src/interface/pxe/pxe_udp.c
@@ -104,6 +104,7 @@ static struct xfer_interface_operations pxe_udp_xfer_operations = {
.close = ignore_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = pxe_udp_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
diff --git a/src/net/tcp.c b/src/net/tcp.c
index 12ca65a6..410be737 100644
--- a/src/net/tcp.c
+++ b/src/net/tcp.c
@@ -897,31 +897,28 @@ static void tcp_xfer_close ( struct xfer_interface *xfer, int rc ) {
}
/**
- * Seek to position
+ * Check flow control window
*
* @v xfer Data transfer interface
- * @v offset Offset to new position
- * @v whence Basis for new position
- * @ret rc Return status code
+ * @ret len Length of window
*/
-static int tcp_xfer_seek ( struct xfer_interface *xfer, off_t offset,
- int whence ) {
+static size_t tcp_xfer_window ( struct xfer_interface *xfer ) {
struct tcp_connection *tcp =
container_of ( xfer, struct tcp_connection, xfer );
- /* TCP doesn't support seeking to arbitrary positions */
- if ( ( whence != SEEK_CUR ) || ( offset != 0 ) )
- return -EINVAL;
-
/* Not ready if we're not in a suitable connection state */
if ( ! TCP_CAN_SEND_DATA ( tcp->tcp_state ) )
- return -EAGAIN;
+ return 0;
- /* Not ready if data queue is non-empty */
+ /* Not ready if data queue is non-empty. This imposes a limit
+ * of only one unACKed packet in the TX queue at any time; we
+ * do this to conserve memory usage.
+ */
if ( ! list_empty ( &tcp->queue ) )
- return -EAGAIN;
+ return 0;
- return 0;
+ /* Return TCP window length */
+ return tcp->snd_win;
}
/**
@@ -951,7 +948,8 @@ static int tcp_xfer_deliver_iob ( struct xfer_interface *xfer,
static struct xfer_interface_operations tcp_xfer_operations = {
.close = tcp_xfer_close,
.vredirect = ignore_xfer_vredirect,
- .seek = tcp_xfer_seek,
+ .seek = ignore_xfer_seek,
+ .window = tcp_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = tcp_xfer_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
diff --git a/src/net/tcp/ftp.c b/src/net/tcp/ftp.c
index 6c09edff..646638ab 100644
--- a/src/net/tcp/ftp.c
+++ b/src/net/tcp/ftp.c
@@ -297,6 +297,7 @@ static struct xfer_interface_operations ftp_control_operations = {
.close = ftp_control_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ftp_control_deliver_raw,
@@ -361,6 +362,7 @@ static struct xfer_interface_operations ftp_data_operations = {
.close = ftp_data_closed,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = ftp_data_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
@@ -393,6 +395,7 @@ static struct xfer_interface_operations ftp_xfer_operations = {
.close = ftp_xfer_closed,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
diff --git a/src/net/tcp/http.c b/src/net/tcp/http.c
index 287a56a0..0c016413 100644
--- a/src/net/tcp/http.c
+++ b/src/net/tcp/http.c
@@ -388,7 +388,7 @@ static void http_step ( struct process *process ) {
const char *query = http->uri->query;
int rc;
- if ( xfer_ready ( &http->socket ) == 0 ) {
+ if ( xfer_window ( &http->socket ) ) {
process_del ( &http->process );
if ( ( rc = xfer_printf ( &http->socket,
"GET %s%s%s HTTP/1.1\r\n"
@@ -425,6 +425,7 @@ static struct xfer_interface_operations http_socket_operations = {
.close = http_socket_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = http_socket_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
@@ -451,6 +452,7 @@ static struct xfer_interface_operations http_xfer_operations = {
.close = http_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
diff --git a/src/net/udp.c b/src/net/udp.c
index 3e33ff17..b4cd8e6b 100644
--- a/src/net/udp.c
+++ b/src/net/udp.c
@@ -415,6 +415,7 @@ static struct xfer_interface_operations udp_xfer_operations = {
.close = udp_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = udp_alloc_iob,
.deliver_iob = udp_xfer_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c
index 5a8203a1..26059341 100644
--- a/src/net/udp/dhcp.c
+++ b/src/net/udp/dhcp.c
@@ -722,6 +722,7 @@ static struct xfer_interface_operations dhcp_xfer_operations = {
.close = ignore_xfer_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = dhcp_deliver_raw,
};
diff --git a/src/net/udp/dns.c b/src/net/udp/dns.c
index 76d5dd7a..aab9cfc2 100644
--- a/src/net/udp/dns.c
+++ b/src/net/udp/dns.c
@@ -433,6 +433,7 @@ static struct xfer_interface_operations dns_socket_operations = {
.close = dns_xfer_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = dns_xfer_deliver_raw,
diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c
index 03a51f9a..106c7047 100644
--- a/src/net/udp/tftp.c
+++ b/src/net/udp/tftp.c
@@ -583,6 +583,7 @@ static struct xfer_interface_operations tftp_socket_operations = {
.close = tftp_socket_close,
.vredirect = xfer_vopen,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = tftp_socket_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
@@ -609,6 +610,7 @@ static struct xfer_interface_operations tftp_xfer_operations = {
.close = tftp_xfer_close,
.vredirect = ignore_xfer_vredirect,
.seek = ignore_xfer_seek,
+ .window = unlimited_xfer_window,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = xfer_deliver_as_raw,
.deliver_raw = ignore_xfer_deliver_raw,
generated by cgit (git 2.34.1) at 2025-02-24 16:49:35 +0000