blob: 96c63dc2509e325c18ce0c63a243971a33d4d925 [file] [log] [blame]
/*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "common.h"
#include <linux/vmalloc.h>
#include <linux/rtnetlink.h>
struct backend_info {
struct xenbus_device *dev;
struct xenvif *vif;
/* This is the state that will be reflected in xenstore when any
* active hotplug script completes.
*/
enum xenbus_state state;
enum xenbus_state frontend_state;
struct xenbus_watch hotplug_status_watch;
u8 have_hotplug_status_watch:1;
};
static int connect_rings(struct backend_info *be, struct xenvif_queue *queue);
static void connect(struct backend_info *be);
static int read_xenbus_vif_flags(struct backend_info *be);
static void backend_create_xenvif(struct backend_info *be);
static void unregister_hotplug_status_watch(struct backend_info *be);
static void set_backend_state(struct backend_info *be,
enum xenbus_state state);
static int netback_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
set_backend_state(be, XenbusStateClosed);
unregister_hotplug_status_watch(be);
if (be->vif) {
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
xenvif_free(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;
}
err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6",
"%d", sg);
if (err) {
message = "writing feature-gso-tcpv6";
goto abort_transaction;
}
/* We support partial checksum setup for IPv6 packets */
err = xenbus_printf(xbt, dev->nodename,
"feature-ipv6-csum-offload",
"%d", 1);
if (err) {
message = "writing feature-ipv6-csum-offload";
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;
}
/*
* Split event channels support, this is optional so it is not
* put inside the above loop.
*/
err = xenbus_printf(XBT_NIL, dev->nodename,
"feature-split-event-channels",
"%u", separate_tx_rx_irq);
if (err)
pr_debug("Error writing feature-split-event-channels\n");
/* Multi-queue support: This is an optional feature. */
err = xenbus_printf(XBT_NIL, dev->nodename,
"multi-queue-max-queues", "%u", xenvif_max_queues);
if (err)
pr_debug("Error writing multi-queue-max-queues\n");
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
be->state = XenbusStateInitWait;
/* 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\n");
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 backend_disconnect(struct backend_info *be)
{
if (be->vif)
xenvif_disconnect(be->vif);
}
static void backend_connect(struct backend_info *be)
{
if (be->vif)
connect(be);
}
static inline void backend_switch_state(struct backend_info *be,
enum xenbus_state state)
{
struct xenbus_device *dev = be->dev;
pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state));
be->state = state;
/* If we are waiting for a hotplug script then defer the
* actual xenbus state change.
*/
if (!be->have_hotplug_status_watch)
xenbus_switch_state(dev, state);
}
/* Handle backend state transitions:
*
* The backend state starts in InitWait and the following transitions are
* allowed.
*
* InitWait -> Connected
*
* ^ \ |
* | \ |
* | \ |
* | \ |
* | \ |
* | \ |
* | V V
*
* Closed <-> Closing
*
* The state argument specifies the eventual state of the backend and the
* function transitions to that state via the shortest path.
*/
static void set_backend_state(struct backend_info *be,
enum xenbus_state state)
{
while (be->state != state) {
switch (be->state) {
case XenbusStateClosed:
switch (state) {
case XenbusStateInitWait:
case XenbusStateConnected:
pr_info("%s: prepare for reconnect\n",
be->dev->nodename);
backend_switch_state(be, XenbusStateInitWait);
break;
case XenbusStateClosing:
backend_switch_state(be, XenbusStateClosing);
break;
default:
BUG();
}
break;
case XenbusStateInitWait:
switch (state) {
case XenbusStateConnected:
backend_connect(be);
backend_switch_state(be, XenbusStateConnected);
break;
case XenbusStateClosing:
case XenbusStateClosed:
backend_switch_state(be, XenbusStateClosing);
break;
default:
BUG();
}
break;
case XenbusStateConnected:
switch (state) {
case XenbusStateInitWait:
case XenbusStateClosing:
case XenbusStateClosed:
backend_disconnect(be);
backend_switch_state(be, XenbusStateClosing);
break;
default:
BUG();
}
break;
case XenbusStateClosing:
switch (state) {
case XenbusStateInitWait:
case XenbusStateConnected:
case XenbusStateClosed:
backend_switch_state(be, XenbusStateClosed);
break;
default:
BUG();
}
break;
default:
BUG();
}
}
}
/**
* 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("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state));
be->frontend_state = frontend_state;
switch (frontend_state) {
case XenbusStateInitialising:
set_backend_state(be, XenbusStateInitWait);
break;
case XenbusStateInitialised:
break;
case XenbusStateConnected:
set_backend_state(be, XenbusStateConnected);
break;
case XenbusStateClosing:
set_backend_state(be, XenbusStateClosing);
break;
case XenbusStateClosed:
set_backend_state(be, XenbusStateClosed);
if (xenbus_dev_is_online(dev))
break;
/* fall through if not online */
case XenbusStateUnknown:
set_backend_state(be, XenbusStateClosed);
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)) {
/* Complete any pending state change */
xenbus_switch_state(be->dev, be->state);
/* 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;
unsigned long credit_bytes, credit_usec;
unsigned int queue_index;
unsigned int requested_num_queues;
struct xenvif_queue *queue;
/* Check whether the frontend requested multiple queues
* and read the number requested.
*/
err = xenbus_scanf(XBT_NIL, dev->otherend,
"multi-queue-num-queues",
"%u", &requested_num_queues);
if (err < 0) {
requested_num_queues = 1; /* Fall back to single queue */
} else if (requested_num_queues > xenvif_max_queues) {
/* buggy or malicious guest */
xenbus_dev_fatal(dev, err,
"guest requested %u queues, exceeding the maximum of %u.",
requested_num_queues, xenvif_max_queues);
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, &credit_bytes, &credit_usec);
read_xenbus_vif_flags(be);
/* Use the number of queues requested by the frontend */
be->vif->queues = vzalloc(requested_num_queues *
sizeof(struct xenvif_queue));
rtnl_lock();
netif_set_real_num_tx_queues(be->vif->dev, requested_num_queues);
rtnl_unlock();
for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
queue = &be->vif->queues[queue_index];
queue->vif = be->vif;
queue->id = queue_index;
snprintf(queue->name, sizeof(queue->name), "%s-q%u",
be->vif->dev->name, queue->id);
err = xenvif_init_queue(queue);
if (err) {
/* xenvif_init_queue() cleans up after itself on
* failure, but we need to clean up any previously
* initialised queues. Set num_queues to i so that
* earlier queues can be destroyed using the regular
* disconnect logic.
*/
rtnl_lock();
netif_set_real_num_tx_queues(be->vif->dev, queue_index);
rtnl_unlock();
goto err;
}
queue->remaining_credit = credit_bytes;
err = connect_rings(be, queue);
if (err) {
/* connect_rings() cleans up after itself on failure,
* but we need to clean up after xenvif_init_queue() here,
* and also clean up any previously initialised queues.
*/
xenvif_deinit_queue(queue);
rtnl_lock();
netif_set_real_num_tx_queues(be->vif->dev, queue_index);
rtnl_unlock();
goto err;
}
}
xenvif_carrier_on(be->vif);
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)
be->have_hotplug_status_watch = 1;
netif_tx_wake_all_queues(be->vif->dev);
return;
err:
if (be->vif->dev->real_num_tx_queues > 0)
xenvif_disconnect(be->vif); /* Clean up existing queues */
vfree(be->vif->queues);
be->vif->queues = NULL;
rtnl_lock();
netif_set_real_num_tx_queues(be->vif->dev, 0);
rtnl_unlock();
return;
}
static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
{
struct xenbus_device *dev = be->dev;
unsigned int num_queues = queue->vif->dev->real_num_tx_queues;
unsigned long tx_ring_ref, rx_ring_ref;
unsigned int tx_evtchn, rx_evtchn;
int err;
char *xspath;
size_t xspathsize;
const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
/* If the frontend requested 1 queue, or we have fallen back
* to single queue due to lack of frontend support for multi-
* queue, expect the remaining XenStore keys in the toplevel
* directory. Otherwise, expect them in a subdirectory called
* queue-N.
*/
if (num_queues == 1) {
xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
if (!xspath) {
xenbus_dev_fatal(dev, -ENOMEM,
"reading ring references");
return -ENOMEM;
}
strcpy(xspath, dev->otherend);
} else {
xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
xspath = kzalloc(xspathsize, GFP_KERNEL);
if (!xspath) {
xenbus_dev_fatal(dev, -ENOMEM,
"reading ring references");
return -ENOMEM;
}
snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
queue->id);
}
err = xenbus_gather(XBT_NIL, xspath,
"tx-ring-ref", "%lu", &tx_ring_ref,
"rx-ring-ref", "%lu", &rx_ring_ref, NULL);
if (err) {
xenbus_dev_fatal(dev, err,
"reading %s/ring-ref",
xspath);
goto err;
}
/* Try split event channels first, then single event channel. */
err = xenbus_gather(XBT_NIL, xspath,
"event-channel-tx", "%u", &tx_evtchn,
"event-channel-rx", "%u", &rx_evtchn, NULL);
if (err < 0) {
err = xenbus_scanf(XBT_NIL, xspath,
"event-channel", "%u", &tx_evtchn);
if (err < 0) {
xenbus_dev_fatal(dev, err,
"reading %s/event-channel(-tx/rx)",
xspath);
goto err;
}
rx_evtchn = tx_evtchn;
}
/* Map the shared frame, irq etc. */
err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
tx_evtchn, rx_evtchn);
if (err) {
xenbus_dev_fatal(dev, err,
"mapping shared-frames %lu/%lu port tx %u rx %u",
tx_ring_ref, rx_ring_ref,
tx_evtchn, rx_evtchn);
goto err;
}
err = 0;
err: /* Regular return falls through with err == 0 */
kfree(xspath);
return err;
}
static int read_xenbus_vif_flags(struct backend_info *be)
{
struct xenvif *vif = be->vif;
struct xenbus_device *dev = be->dev;
unsigned int rx_copy;
int err, val;
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;
vif->gso_mask = 0;
vif->gso_prefix_mask = 0;
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
"%d", &val) < 0)
val = 0;
if (val)
vif->gso_mask |= GSO_BIT(TCPV4);
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
"%d", &val) < 0)
val = 0;
if (val)
vif->gso_prefix_mask |= GSO_BIT(TCPV4);
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
"%d", &val) < 0)
val = 0;
if (val)
vif->gso_mask |= GSO_BIT(TCPV6);
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6-prefix",
"%d", &val) < 0)
val = 0;
if (val)
vif->gso_prefix_mask |= GSO_BIT(TCPV6);
if (vif->gso_mask & vif->gso_prefix_mask) {
xenbus_dev_fatal(dev, err,
"%s: gso and gso prefix flags are not "
"mutually exclusive",
dev->otherend);
return -EOPNOTSUPP;
}
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
"%d", &val) < 0)
val = 0;
vif->ip_csum = !val;
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
"%d", &val) < 0)
val = 0;
vif->ipv6_csum = !!val;
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);
}
void xenvif_xenbus_fini(void)
{
return xenbus_unregister_driver(&netback_driver);
}