--- /dev/null
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+#include <ipxe/interface.h>
+
+/** @file
+ *
+ * Object interfaces
+ *
+ */
+
+/*****************************************************************************
+ *
+ * The null interface
+ *
+ */
+
+/**
+ * Close null interface
+ *
+ * @v intf Null interface
+ * @v rc Reason for close
+ */
+static void null_intf_close ( struct interface *intf __unused,
+ int rc __unused ) {
+
+ /* Do nothing. In particular, do not call intf_restart(),
+ * since that would result in an infinite loop.
+ */
+}
+
+/** Null interface operations */
+static struct interface_operation null_intf_op[] = {
+ INTF_OP ( intf_close, struct interface *, null_intf_close ),
+};
+
+/** Null interface descriptor */
+struct interface_descriptor null_intf_desc =
+ INTF_DESC_PURE ( null_intf_op );
+
+/** The null interface */
+struct interface null_intf = INTF_INIT ( null_intf_desc );
+
+/*****************************************************************************
+ *
+ * Object interface plumbing
+ *
+ */
+
+/**
+ * Plug an object interface into a new destination object interface
+ *
+ * @v intf Object interface
+ * @v dest New destination object interface
+ *
+ * The reference to the existing destination interface is dropped, a
+ * reference to the new destination interface is obtained, and the
+ * interface is updated to point to the new destination interface.
+ *
+ * Note that there is no "unplug" call; instead you must plug the
+ * interface into a null interface.
+ */
+void intf_plug ( struct interface *intf, struct interface *dest ) {
+ DBGC ( INTF_COL ( intf ),
+ "INTF " INTF_INTF_FMT " replug to " INTF_FMT "\n",
+ INTF_INTF_DBG ( intf, intf->dest ), INTF_DBG ( dest ) );
+ intf_get ( dest );
+ intf_put ( intf->dest );
+ intf->dest = dest;
+}
+
+/**
+ * Plug two object interfaces together
+ *
+ * @v a Object interface A
+ * @v b Object interface B
+ *
+ * Plugs interface A into interface B, and interface B into interface
+ * A. (The basic plug() function is unidirectional; this function is
+ * merely a shorthand for two calls to plug(), hence the name.)
+ */
+void intf_plug_plug ( struct interface *a, struct interface *b ) {
+ intf_plug ( a, b );
+ intf_plug ( b, a );
+}
+
+/**
+ * Unplug an object interface
+ *
+ * @v intf Object interface
+ */
+void intf_unplug ( struct interface *intf ) {
+ intf_plug ( intf, &null_intf );
+}
+
+/**
+ * Ignore all further operations on an object interface
+ *
+ * @v intf Object interface
+ */
+void intf_nullify ( struct interface *intf ) {
+ intf->desc = &null_intf_desc;
+}
+
+/**
+ * Increment reference count on an object interface
+ *
+ * @v intf Object interface
+ * @ret intf Object interface
+ */
+struct interface * intf_get ( struct interface *intf ) {
+ ref_get ( intf->refcnt );
+ return intf;
+}
+
+/**
+ * Decrement reference count on an object interface
+ *
+ * @v intf Object interface
+ */
+void intf_put ( struct interface *intf ) {
+ ref_put ( intf->refcnt );
+}
+
+/**
+ * Get pointer to object containing object interface
+ *
+ * @v intf Object interface
+ * @ret object Containing object
+ */
+void * intf_object ( struct interface *intf ) {
+ return ( ( ( void * ) intf ) - intf->desc->offset );
+}
+
+/**
+ * Get pass-through interface
+ *
+ * @v intf Object interface
+ * @ret passthru Pass-through interface, or NULL
+ */
+static struct interface * intf_get_passthru ( struct interface *intf ) {
+ struct interface_descriptor *desc = intf->desc;
+
+ if ( desc->passthru_offset ) {
+ return ( ( ( void * ) intf ) + desc->passthru_offset );
+ } else {
+ return NULL;
+ }
+}
+
+/**
+ * Get object interface destination and operation method (without pass-through)
+ *
+ * @v intf Object interface
+ * @v type Operation type
+ * @ret dest Destination interface
+ * @ret func Implementing method, or NULL
+ */
+void * intf_get_dest_op_no_passthru_untyped ( struct interface *intf,
+ void *type,
+ struct interface **dest ) {
+ struct interface_descriptor *desc;
+ struct interface_operation *op;
+ unsigned int i;
+
+ *dest = intf_get ( intf->dest );
+ desc = (*dest)->desc;
+ for ( i = desc->num_op, op = desc->op ; i ; i--, op++ ) {
+ if ( op->type == type )
+ return op->func;
+ }
+
+ return NULL;
+}
+
+/**
+ * Get object interface destination and operation method
+ *
+ * @v intf Object interface
+ * @v type Operation type
+ * @ret dest Destination interface
+ * @ret func Implementing method, or NULL
+ */
+void * intf_get_dest_op_untyped ( struct interface *intf, void *type,
+ struct interface **dest ) {
+ void *func;
+
+ while ( 1 ) {
+
+ /* Search for an implementing method provided by the
+ * current destination interface.
+ */
+ func = intf_get_dest_op_no_passthru_untyped( intf, type, dest );
+ if ( func )
+ return func;
+
+ /* Pass through to the underlying interface, if applicable */
+ if ( ! ( intf = intf_get_passthru ( *dest ) ) )
+ return NULL;
+ intf_put ( *dest );
+ }
+}
+
+/*****************************************************************************
+ *
+ * Generic interface operations
+ *
+ */
+
+/**
+ * Close an object interface
+ *
+ * @v intf Object interface
+ * @v rc Reason for close
+ *
+ * Note that this function merely informs the destination object that
+ * the interface is about to be closed; it doesn't actually disconnect
+ * the interface. In most cases, you probably want to use
+ * intf_shutdown() or intf_restart() instead.
+ */
+void intf_close ( struct interface *intf, int rc ) {
+ struct interface *dest;
+ intf_close_TYPE ( void * ) *op =
+ intf_get_dest_op ( intf, intf_close, &dest );
+ void *object = intf_object ( dest );
+
+ DBGC ( INTF_COL ( intf ), "INTF " INTF_INTF_FMT " close (%s)\n",
+ INTF_INTF_DBG ( intf, dest ), strerror ( rc ) );
+
+ if ( op ) {
+ op ( object, rc );
+ } else {
+ /* Default is to restart the interface */
+ intf_restart ( dest, rc );
+ }
+
+ intf_put ( dest );
+}
+
+/**
+ * Shut down an object interface
+ *
+ * @v intf Object interface
+ * @v rc Reason for close
+ *
+ * Blocks further operations from being received via the interface,
+ * executes a close operation on the destination interface, and
+ * unplugs the interface.
+ */
+void intf_shutdown ( struct interface *intf, int rc ) {
+
+ DBGC ( INTF_COL ( intf ), "INTF " INTF_FMT " shutting down (%s)\n",
+ INTF_DBG ( intf ), strerror ( rc ) );
+
+ /* Block further operations */
+ intf_nullify ( intf );
+
+ /* Notify destination of close */
+ intf_close ( intf, rc );
+
+ /* Unplug interface */
+ intf_unplug ( intf );
+}
+
+/**
+ * Shut down and restart an object interface
+ *
+ * @v intf Object interface
+ * @v rc Reason for close
+ *
+ * Shuts down the interface, then unblocks operations that were
+ * blocked during shutdown.
+ */
+void intf_restart ( struct interface *intf, int rc ) {
+ struct interface_descriptor *desc = intf->desc;
+
+ /* Shut down the interface */
+ intf_shutdown ( intf, rc );
+
+ DBGC ( INTF_COL ( intf ), "INTF " INTF_FMT " restarting\n",
+ INTF_DBG ( intf ) );
+
+ /* Restore the interface descriptor. Must be done after
+ * shutdown (rather than inhibiting intf_shutdown() from
+ * nullifying the descriptor) in order to avoid a potential
+ * infinite loop as the intf_close() operations on each side
+ * of the link call each other recursively.
+ */
+ intf->desc = desc;
+}
Code Review / kvmfornfv.git / blobdiff