- 根目录:
- drivers
- net
- xen-netback
- xenbus.c
/*
* Xenbus code for netif backend
*
* Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
* Copyright (C) 2005 XenSource Ltd
*
* 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
* (at your option) 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "common.h"
struct backend_info {
struct xenbus_device *dev;
struct xenvif *vif;
enum xenbus_state frontend_state;
struct xenbus_watch hotplug_status_watch;
u8 have_hotplug_status_watch:1;
};
static int connect_rings(struct backend_info *);
static void connect(struct backend_info *);
static void backend_create_xenvif(struct backend_info *be);
static void unregister_hotplug_status_watch(struct backend_info *be);
static int netback_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
unregister_hotplug_status_watch(be);
if (be->vif) {
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
xenvif_disconnect(be->vif);
be->vif = NULL;
}
kfree(be);
dev_set_drvdata(&dev->dev, NULL);
return 0;
}
/**
* Entry point to this code when a new device is created. Allocate the basic
* structures and switch to InitWait.
*/
static int netback_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
const char *message;
struct xenbus_transaction xbt;
int err;
int sg;
struct backend_info *be = kzalloc(sizeof(struct backend_info),
GFP_KERNEL);
if (!be) {
xenbus_dev_fatal(dev, -ENOMEM,
"allocating backend structure");
return -ENOMEM;
}
be->dev = dev;
dev_set_drvdata(&dev->dev, be);
sg = 1;
do {
err = xenbus_transaction_start(&xbt);
if (err) {
xenbus_dev_fatal(dev, err, "starting transaction");
goto fail;
}
err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
if (err) {
message = "writing feature-sg";
goto abort_transaction;
}
err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
"%d", sg);
if (err) {
message = "writing feature-gso-tcpv4";
goto abort_transaction;
}
/* We support rx-copy path. */
err = xenbus_printf(xbt, dev->nodename,
"feature-rx-copy", "%d", 1);
if (err) {
message = "writing feature-rx-copy";
goto abort_transaction;
}
/*
* We don't support rx-flip path (except old guests who don't
* grok this feature flag).
*/
err = xenbus_printf(xbt, dev->nodename,
"feature-rx-flip", "%d", 0);
if (err) {
message = "writing feature-rx-flip";
goto abort_transaction;
}
err = xenbus_transaction_end(xbt, 0);
} while (err == -EAGAIN);
if (err) {
xenbus_dev_fatal(dev, err, "completing transaction");
goto fail;
}
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
/* This kicks hotplug scripts, so do it immediately. */
backend_create_xenvif(be);
return 0;
abort_transaction:
xenbus_transaction_end(xbt, 1);
xenbus_dev_fatal(dev, err, "%s", message);
fail:
pr_debug("failed");
netback_remove(dev);
return err;
}
/*
* Handle the creation of the hotplug script environment. We add the script
* and vif variables to the environment, for the benefit of the vif-* hotplug
* scripts.
*/
static int netback_uevent(struct xenbus_device *xdev,
struct kobj_uevent_env *env)
{
struct backend_info *be = dev_get_drvdata(&xdev->dev);
char *val;
val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL);
if (IS_ERR(val)) {
int err = PTR_ERR(val);
xenbus_dev_fatal(xdev, err, "reading script");
return err;
} else {
if (add_uevent_var(env, "script=%s", val)) {
kfree(val);
return -ENOMEM;
}
kfree(val);
}
if (!be || !be->vif)
return 0;
return add_uevent_var(env, "vif=%s", be->vif->dev->name);
}
static void backend_create_xenvif(struct backend_info *be)
{
int err;
long handle;
struct xenbus_device *dev = be->dev;
if (be->vif != NULL)
return;
err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
if (err != 1) {
xenbus_dev_fatal(dev, err, "reading handle");
return;
}
be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
if (IS_ERR(be->vif)) {
err = PTR_ERR(be->vif);
be->vif = NULL;
xenbus_dev_fatal(dev, err, "creating interface");
return;
}
kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
}
static void disconnect_backend(struct xenbus_device *dev)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
if (be->vif) {
xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
xenvif_disconnect(be->vif);
be->vif = NULL;
}
}
/**
* Callback received when the frontend's state changes.
*/
static void frontend_changed(struct xenbus_device *dev,
enum xenbus_state frontend_state)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
pr_debug("frontend state %s", xenbus_strstate(frontend_state));
be->frontend_state = frontend_state;
switch (frontend_state) {
case XenbusStateInitialising:
if (dev->state == XenbusStateClosed) {
printk(KERN_INFO "%s: %s: prepare for reconnect\n",
__func__, dev->nodename);
xenbus_switch_state(dev, XenbusStateInitWait);
}
break;
case XenbusStateInitialised:
break;
case XenbusStateConnected:
if (dev->state == XenbusStateConnected)
break;
backend_create_xenvif(be);
if (be->vif)
connect(be);
break;
case XenbusStateClosing:
if (be->vif)
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
disconnect_backend(dev);
xenbus_switch_state(dev, XenbusStateClosing);
break;
case XenbusStateClosed:
xenbus_switch_state(dev, XenbusStateClosed);
if (xenbus_dev_is_online(dev))
break;
/* fall through if not online */
case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
default:
xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
frontend_state);
break;
}
}
static void xen_net_read_rate(struct xenbus_device *dev,
unsigned long *bytes, unsigned long *usec)
{
char *s, *e;
unsigned long b, u;
char *ratestr;
/* Default to unlimited bandwidth. */
*bytes = ~0UL;
*usec = 0;
ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
if (IS_ERR(ratestr))
return;
s = ratestr;
b = simple_strtoul(s, &e, 10);
if ((s == e) || (*e != ','))
goto fail;
s = e + 1;
u = simple_strtoul(s, &e, 10);
if ((s == e) || (*e != '\0'))
goto fail;
*bytes = b;
*usec = u;
kfree(ratestr);
return;
fail:
pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
kfree(ratestr);
}
static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
{
char *s, *e, *macstr;
int i;
macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
if (IS_ERR(macstr))
return PTR_ERR(macstr);
for (i = 0; i < ETH_ALEN; i++) {
mac[i] = simple_strtoul(s, &e, 16);
if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
kfree(macstr);
return -ENOENT;
}
s = e+1;
}
kfree(macstr);
return 0;
}
static void unregister_hotplug_status_watch(struct backend_info *be)
{
if (be->have_hotplug_status_watch) {
unregister_xenbus_watch(&be->hotplug_status_watch);
kfree(be->hotplug_status_watch.node);
}
be->have_hotplug_status_watch = 0;
}
static void hotplug_status_changed(struct xenbus_watch *watch,
const char **vec,
unsigned int vec_size)
{
struct backend_info *be = container_of(watch,
struct backend_info,
hotplug_status_watch);
char *str;
unsigned int len;
str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
if (IS_ERR(str))
return;
if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
xenbus_switch_state(be->dev, XenbusStateConnected);
/* Not interested in this watch anymore. */
unregister_hotplug_status_watch(be);
}
kfree(str);
}
static void connect(struct backend_info *be)
{
int err;
struct xenbus_device *dev = be->dev;
err = connect_rings(be);
if (err)
return;
err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
if (err) {
xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
return;
}
xen_net_read_rate(dev, &be->vif->credit_bytes,
&be->vif->credit_usec);
be->vif->remaining_credit = be->vif->credit_bytes;
unregister_hotplug_status_watch(be);
err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
hotplug_status_changed,
"%s/%s", dev->nodename, "hotplug-status");
if (err) {
/* Switch now, since we can't do a watch. */
xenbus_switch_state(dev, XenbusStateConnected);
} else {
be->have_hotplug_status_watch = 1;
}
netif_wake_queue(be->vif->dev);
}
static int connect_rings(struct backend_info *be)
{
struct xenvif *vif = be->vif;
struct xenbus_device *dev = be->dev;
unsigned long tx_ring_ref, rx_ring_ref;
unsigned int evtchn, rx_copy;
int err;
int val;
err = xenbus_gather(XBT_NIL, dev->otherend,
"tx-ring-ref", "%lu", &tx_ring_ref,
"rx-ring-ref", "%lu", &rx_ring_ref,
"event-channel", "%u", &evtchn, NULL);
if (err) {
xenbus_dev_fatal(dev, err,
"reading %s/ring-ref and event-channel",
dev->otherend);
return err;
}
err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
&rx_copy);
if (err == -ENOENT) {
err = 0;
rx_copy = 0;
}
if (err < 0) {
xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
dev->otherend);
return err;
}
if (!rx_copy)
return -EOPNOTSUPP;
if (vif->dev->tx_queue_len != 0) {
if (xenbus_scanf(XBT_NIL, dev->otherend,
"feature-rx-notify", "%d", &val) < 0)
val = 0;
if (val)
vif->can_queue = 1;
else
/* Must be non-zero for pfifo_fast to work. */
vif->dev->tx_queue_len = 1;
}
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
"%d", &val) < 0)
val = 0;
vif->can_sg = !!val;
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
"%d", &val) < 0)
val = 0;
vif->gso = !!val;
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
"%d", &val) < 0)
val = 0;
vif->gso_prefix = !!val;
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
"%d", &val) < 0)
val = 0;
vif->csum = !val;
/* Map the shared frame, irq etc. */
err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, evtchn);
if (err) {
xenbus_dev_fatal(dev, err,
"mapping shared-frames %lu/%lu port %u",
tx_ring_ref, rx_ring_ref, evtchn);
return err;
}
return 0;
}
/* ** Driver Registration ** */
static const struct xenbus_device_id netback_ids[] = {
{ "vif" },
{ "" }
};
static DEFINE_XENBUS_DRIVER(netback, ,
.probe = netback_probe,
.remove = netback_remove,
.uevent = netback_uevent,
.otherend_changed = frontend_changed,
);
int xenvif_xenbus_init(void)
{
return xenbus_register_backend(&netback_driver);
}