526 строки
12 KiB
C
526 строки
12 KiB
C
/*
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* Xenbus code for netif backend
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*
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* Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
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* Copyright (C) 2005 XenSource Ltd
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "common.h"
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struct backend_info {
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struct xenbus_device *dev;
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struct xenvif *vif;
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enum xenbus_state frontend_state;
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struct xenbus_watch hotplug_status_watch;
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u8 have_hotplug_status_watch:1;
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};
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static int connect_rings(struct backend_info *);
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static void connect(struct backend_info *);
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static void backend_create_xenvif(struct backend_info *be);
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static void unregister_hotplug_status_watch(struct backend_info *be);
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static int netback_remove(struct xenbus_device *dev)
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{
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struct backend_info *be = dev_get_drvdata(&dev->dev);
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unregister_hotplug_status_watch(be);
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if (be->vif) {
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kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
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xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
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xenvif_free(be->vif);
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be->vif = NULL;
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}
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kfree(be);
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dev_set_drvdata(&dev->dev, NULL);
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return 0;
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}
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/**
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* Entry point to this code when a new device is created. Allocate the basic
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* structures and switch to InitWait.
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*/
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static int netback_probe(struct xenbus_device *dev,
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const struct xenbus_device_id *id)
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{
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const char *message;
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struct xenbus_transaction xbt;
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int err;
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int sg;
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struct backend_info *be = kzalloc(sizeof(struct backend_info),
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GFP_KERNEL);
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if (!be) {
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xenbus_dev_fatal(dev, -ENOMEM,
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"allocating backend structure");
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return -ENOMEM;
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}
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be->dev = dev;
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dev_set_drvdata(&dev->dev, be);
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sg = 1;
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do {
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err = xenbus_transaction_start(&xbt);
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if (err) {
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xenbus_dev_fatal(dev, err, "starting transaction");
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goto fail;
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}
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err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
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if (err) {
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message = "writing feature-sg";
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goto abort_transaction;
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}
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err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
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"%d", sg);
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if (err) {
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message = "writing feature-gso-tcpv4";
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goto abort_transaction;
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}
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/* We support rx-copy path. */
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err = xenbus_printf(xbt, dev->nodename,
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"feature-rx-copy", "%d", 1);
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if (err) {
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message = "writing feature-rx-copy";
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goto abort_transaction;
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}
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/*
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* We don't support rx-flip path (except old guests who don't
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* grok this feature flag).
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*/
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err = xenbus_printf(xbt, dev->nodename,
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"feature-rx-flip", "%d", 0);
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if (err) {
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message = "writing feature-rx-flip";
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goto abort_transaction;
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}
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err = xenbus_transaction_end(xbt, 0);
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} while (err == -EAGAIN);
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if (err) {
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xenbus_dev_fatal(dev, err, "completing transaction");
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goto fail;
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}
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/*
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* Split event channels support, this is optional so it is not
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* put inside the above loop.
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*/
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err = xenbus_printf(XBT_NIL, dev->nodename,
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"feature-split-event-channels",
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"%u", separate_tx_rx_irq);
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if (err)
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pr_debug("Error writing feature-split-event-channels\n");
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err = xenbus_switch_state(dev, XenbusStateInitWait);
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if (err)
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goto fail;
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/* This kicks hotplug scripts, so do it immediately. */
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backend_create_xenvif(be);
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return 0;
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abort_transaction:
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xenbus_transaction_end(xbt, 1);
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xenbus_dev_fatal(dev, err, "%s", message);
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fail:
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pr_debug("failed\n");
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netback_remove(dev);
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return err;
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}
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/*
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* Handle the creation of the hotplug script environment. We add the script
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* and vif variables to the environment, for the benefit of the vif-* hotplug
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* scripts.
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*/
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static int netback_uevent(struct xenbus_device *xdev,
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struct kobj_uevent_env *env)
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{
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struct backend_info *be = dev_get_drvdata(&xdev->dev);
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char *val;
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val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL);
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if (IS_ERR(val)) {
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int err = PTR_ERR(val);
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xenbus_dev_fatal(xdev, err, "reading script");
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return err;
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} else {
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if (add_uevent_var(env, "script=%s", val)) {
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kfree(val);
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return -ENOMEM;
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}
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kfree(val);
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}
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if (!be || !be->vif)
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return 0;
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return add_uevent_var(env, "vif=%s", be->vif->dev->name);
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}
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static void backend_create_xenvif(struct backend_info *be)
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{
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int err;
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long handle;
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struct xenbus_device *dev = be->dev;
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if (be->vif != NULL)
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return;
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err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
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if (err != 1) {
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xenbus_dev_fatal(dev, err, "reading handle");
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return;
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}
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be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
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if (IS_ERR(be->vif)) {
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err = PTR_ERR(be->vif);
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be->vif = NULL;
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xenbus_dev_fatal(dev, err, "creating interface");
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return;
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}
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kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
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}
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static void disconnect_backend(struct xenbus_device *dev)
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{
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struct backend_info *be = dev_get_drvdata(&dev->dev);
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if (be->vif)
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xenvif_disconnect(be->vif);
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}
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static void destroy_backend(struct xenbus_device *dev)
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{
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struct backend_info *be = dev_get_drvdata(&dev->dev);
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if (be->vif) {
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kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
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xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
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xenvif_free(be->vif);
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be->vif = NULL;
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}
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}
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/**
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* Callback received when the frontend's state changes.
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*/
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static void frontend_changed(struct xenbus_device *dev,
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enum xenbus_state frontend_state)
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{
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struct backend_info *be = dev_get_drvdata(&dev->dev);
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pr_debug("frontend state %s\n", xenbus_strstate(frontend_state));
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be->frontend_state = frontend_state;
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switch (frontend_state) {
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case XenbusStateInitialising:
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if (dev->state == XenbusStateClosed) {
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pr_info("%s: prepare for reconnect\n", dev->nodename);
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xenbus_switch_state(dev, XenbusStateInitWait);
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}
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break;
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case XenbusStateInitialised:
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break;
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case XenbusStateConnected:
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if (dev->state == XenbusStateConnected)
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break;
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if (be->vif)
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connect(be);
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break;
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case XenbusStateClosing:
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disconnect_backend(dev);
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xenbus_switch_state(dev, XenbusStateClosing);
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break;
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case XenbusStateClosed:
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xenbus_switch_state(dev, XenbusStateClosed);
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if (xenbus_dev_is_online(dev))
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break;
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destroy_backend(dev);
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/* fall through if not online */
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case XenbusStateUnknown:
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device_unregister(&dev->dev);
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break;
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default:
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xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
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frontend_state);
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break;
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}
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}
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static void xen_net_read_rate(struct xenbus_device *dev,
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unsigned long *bytes, unsigned long *usec)
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{
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char *s, *e;
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unsigned long b, u;
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char *ratestr;
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/* Default to unlimited bandwidth. */
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*bytes = ~0UL;
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*usec = 0;
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ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
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if (IS_ERR(ratestr))
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return;
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s = ratestr;
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b = simple_strtoul(s, &e, 10);
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if ((s == e) || (*e != ','))
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goto fail;
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s = e + 1;
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u = simple_strtoul(s, &e, 10);
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if ((s == e) || (*e != '\0'))
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goto fail;
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*bytes = b;
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*usec = u;
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kfree(ratestr);
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return;
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fail:
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pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
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kfree(ratestr);
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}
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static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
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{
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char *s, *e, *macstr;
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int i;
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macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
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if (IS_ERR(macstr))
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return PTR_ERR(macstr);
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for (i = 0; i < ETH_ALEN; i++) {
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mac[i] = simple_strtoul(s, &e, 16);
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if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
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kfree(macstr);
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return -ENOENT;
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}
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s = e+1;
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}
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kfree(macstr);
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return 0;
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}
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static void unregister_hotplug_status_watch(struct backend_info *be)
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{
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if (be->have_hotplug_status_watch) {
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unregister_xenbus_watch(&be->hotplug_status_watch);
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kfree(be->hotplug_status_watch.node);
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}
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be->have_hotplug_status_watch = 0;
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}
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static void hotplug_status_changed(struct xenbus_watch *watch,
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const char **vec,
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unsigned int vec_size)
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{
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struct backend_info *be = container_of(watch,
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struct backend_info,
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hotplug_status_watch);
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char *str;
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unsigned int len;
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str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
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if (IS_ERR(str))
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return;
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if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
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xenbus_switch_state(be->dev, XenbusStateConnected);
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/* Not interested in this watch anymore. */
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unregister_hotplug_status_watch(be);
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}
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kfree(str);
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}
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static void connect(struct backend_info *be)
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{
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int err;
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struct xenbus_device *dev = be->dev;
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err = connect_rings(be);
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if (err)
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return;
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err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
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if (err) {
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xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
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return;
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}
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xen_net_read_rate(dev, &be->vif->credit_bytes,
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&be->vif->credit_usec);
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be->vif->remaining_credit = be->vif->credit_bytes;
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unregister_hotplug_status_watch(be);
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err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
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hotplug_status_changed,
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"%s/%s", dev->nodename, "hotplug-status");
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if (err) {
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/* Switch now, since we can't do a watch. */
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xenbus_switch_state(dev, XenbusStateConnected);
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} else {
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be->have_hotplug_status_watch = 1;
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}
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netif_wake_queue(be->vif->dev);
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}
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static int connect_rings(struct backend_info *be)
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{
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struct xenvif *vif = be->vif;
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struct xenbus_device *dev = be->dev;
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unsigned long tx_ring_ref, rx_ring_ref;
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unsigned int tx_evtchn, rx_evtchn, rx_copy;
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int err;
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int val;
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err = xenbus_gather(XBT_NIL, dev->otherend,
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"tx-ring-ref", "%lu", &tx_ring_ref,
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"rx-ring-ref", "%lu", &rx_ring_ref, NULL);
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if (err) {
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xenbus_dev_fatal(dev, err,
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"reading %s/ring-ref",
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dev->otherend);
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return err;
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}
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/* Try split event channels first, then single event channel. */
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err = xenbus_gather(XBT_NIL, dev->otherend,
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"event-channel-tx", "%u", &tx_evtchn,
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"event-channel-rx", "%u", &rx_evtchn, NULL);
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if (err < 0) {
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err = xenbus_scanf(XBT_NIL, dev->otherend,
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"event-channel", "%u", &tx_evtchn);
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if (err < 0) {
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xenbus_dev_fatal(dev, err,
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"reading %s/event-channel(-tx/rx)",
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dev->otherend);
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return err;
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}
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rx_evtchn = tx_evtchn;
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}
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err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
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&rx_copy);
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if (err == -ENOENT) {
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err = 0;
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rx_copy = 0;
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}
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if (err < 0) {
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xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
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dev->otherend);
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return err;
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}
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if (!rx_copy)
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return -EOPNOTSUPP;
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if (vif->dev->tx_queue_len != 0) {
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if (xenbus_scanf(XBT_NIL, dev->otherend,
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"feature-rx-notify", "%d", &val) < 0)
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val = 0;
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if (val)
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vif->can_queue = 1;
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else
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/* Must be non-zero for pfifo_fast to work. */
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vif->dev->tx_queue_len = 1;
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}
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if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
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"%d", &val) < 0)
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val = 0;
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vif->can_sg = !!val;
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if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
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"%d", &val) < 0)
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val = 0;
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vif->gso = !!val;
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if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
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"%d", &val) < 0)
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val = 0;
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vif->gso_prefix = !!val;
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if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
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"%d", &val) < 0)
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val = 0;
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vif->csum = !val;
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/* Map the shared frame, irq etc. */
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err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref,
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tx_evtchn, rx_evtchn);
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if (err) {
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xenbus_dev_fatal(dev, err,
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"mapping shared-frames %lu/%lu port tx %u rx %u",
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tx_ring_ref, rx_ring_ref,
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tx_evtchn, rx_evtchn);
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return err;
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}
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return 0;
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}
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/* ** Driver Registration ** */
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static const struct xenbus_device_id netback_ids[] = {
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{ "vif" },
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{ "" }
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};
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static DEFINE_XENBUS_DRIVER(netback, ,
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.probe = netback_probe,
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.remove = netback_remove,
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.uevent = netback_uevent,
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.otherend_changed = frontend_changed,
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);
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int xenvif_xenbus_init(void)
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{
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return xenbus_register_backend(&netback_driver);
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}
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void xenvif_xenbus_fini(void)
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{
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return xenbus_unregister_driver(&netback_driver);
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}
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