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path: root/drivers/net/xen-netback/xenbus.c
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Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
-rw-r--r--drivers/net/xen-netback/xenbus.c490
1 files changed, 490 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
new file mode 100644
index 000000000000..22b8c3505991
--- /dev/null
+++ b/drivers/net/xen-netback/xenbus.c
@@ -0,0 +1,490 @@
+/*
+ * 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;
+ int 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 struct xenbus_driver netback = {
+ .name = "vif",
+ .owner = THIS_MODULE,
+ .ids = netback_ids,
+ .probe = netback_probe,
+ .remove = netback_remove,
+ .uevent = netback_uevent,
+ .otherend_changed = frontend_changed,
+};
+
+int xenvif_xenbus_init(void)
+{
+ return xenbus_register_backend(&netback);
+}