diff options
Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
| -rw-r--r-- | drivers/net/xen-netback/xenbus.c | 490 |
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 00000000000..22b8c350599 --- /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); +} |