drivers/net/xen-netback/interface.c

   1 /*
   2  * Network-device interface management.
   3  *
   4  * Copyright (c) 2004-2005, Keir Fraser
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation; or, when distributed
   9  * separately from the Linux kernel or incorporated into other
  10  * software packages, subject to the following license:
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a copy
  13  * of this source file (the "Software"), to deal in the Software without
  14  * restriction, including without limitation the rights to use, copy, modify,
  15  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  16  * and to permit persons to whom the Software is furnished to do so, subject to
  17  * the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included in
  20  * all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28  * IN THE SOFTWARE.
  29  */
  30
  31 #include "common.h"
  32
  33 #include <linux/ethtool.h>
  34 #include <linux/rtnetlink.h>
  35 #include <linux/if_vlan.h>
  36
  37 #include <xen/events.h>
  38 #include <asm/xen/hypercall.h>
  39
  40 #define XENVIF_QUEUE_LENGTH 32
  41
  42 void xenvif_get(struct xenvif *vif)
  43 {
  44         atomic_inc(&vif->refcnt);
  45 }
  46
  47 void xenvif_put(struct xenvif *vif)
  48 {
  49         if (atomic_dec_and_test(&vif->refcnt))
  50                 wake_up(&vif->waiting_to_free);
  51 }
  52
  53 int xenvif_schedulable(struct xenvif *vif)
  54 {
  55         return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
  56 }
  57
  58 static int xenvif_rx_schedulable(struct xenvif *vif)
  59 {
  60         return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
  61 }
  62
  63 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
  64 {
  65         struct xenvif *vif = dev_id;
  66
  67         if (vif->netbk == NULL)
  68                 return IRQ_NONE;
  69
  70         xen_netbk_schedule_xenvif(vif);
  71
  72         if (xenvif_rx_schedulable(vif))
  73                 netif_wake_queue(vif->dev);
  74
  75         return IRQ_HANDLED;
  76 }
  77
  78 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
  79 {
  80         struct xenvif *vif = netdev_priv(dev);
  81
  82         BUG_ON(skb->dev != dev);
  83
  84         if (vif->netbk == NULL)
  85                 goto drop;
  86
  87         /* Drop the packet if the target domain has no receive buffers. */
  88         if (!xenvif_rx_schedulable(vif))
  89                 goto drop;
  90
  91         /* Reserve ring slots for the worst-case number of fragments. */
  92         vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
  93         xenvif_get(vif);
  94
  95         if (vif->can_queue && xen_netbk_must_stop_queue(vif))
  96                 netif_stop_queue(dev);
  97
  98         xen_netbk_queue_tx_skb(vif, skb);
  99
 100         return NETDEV_TX_OK;
 101
 102  drop:
 103         vif->dev->stats.tx_dropped++;
 104         dev_kfree_skb(skb);
 105         return NETDEV_TX_OK;
 106 }
 107
 108 void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
 109 {
 110         netif_rx_ni(skb);
 111 }
 112
 113 void xenvif_notify_tx_completion(struct xenvif *vif)
 114 {
 115         if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
 116                 netif_wake_queue(vif->dev);
 117 }
 118
 119 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 120 {
 121         struct xenvif *vif = netdev_priv(dev);
 122         return &vif->dev->stats;
 123 }
 124
 125 static void xenvif_up(struct xenvif *vif)
 126 {
 127         xen_netbk_add_xenvif(vif);
 128         enable_irq(vif->irq);
 129         xen_netbk_check_rx_xenvif(vif);
 130 }
 131
 132 static void xenvif_down(struct xenvif *vif)
 133 {
 134         disable_irq(vif->irq);
 135         xen_netbk_deschedule_xenvif(vif);
 136         xen_netbk_remove_xenvif(vif);
 137 }
 138
 139 static int xenvif_open(struct net_device *dev)
 140 {
 141         struct xenvif *vif = netdev_priv(dev);
 142         if (netif_carrier_ok(dev))
 143                 xenvif_up(vif);
 144         netif_start_queue(dev);
 145         return 0;
 146 }
 147
 148 static int xenvif_close(struct net_device *dev)
 149 {
 150         struct xenvif *vif = netdev_priv(dev);
 151         if (netif_carrier_ok(dev))
 152                 xenvif_down(vif);
 153         netif_stop_queue(dev);
 154         return 0;
 155 }
 156
 157 static int xenvif_change_mtu(struct net_device *dev, int mtu)
 158 {
 159         struct xenvif *vif = netdev_priv(dev);
 160         int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
 161
 162         if (mtu > max)
 163                 return -EINVAL;
 164         dev->mtu = mtu;
 165         return 0;
 166 }
 167
 168 static u32 xenvif_fix_features(struct net_device *dev, u32 features)
 169 {
 170         struct xenvif *vif = netdev_priv(dev);
 171
 172         if (!vif->can_sg)
 173                 features &= ~NETIF_F_SG;
 174         if (!vif->gso && !vif->gso_prefix)
 175                 features &= ~NETIF_F_TSO;
 176         if (!vif->csum)
 177                 features &= ~NETIF_F_IP_CSUM;
 178
 179         return features;
 180 }
 181
 182 static const struct xenvif_stat {
 183         char name[ETH_GSTRING_LEN];
 184         u16 offset;
 185 } xenvif_stats[] = {
 186         {
 187                 "rx_gso_checksum_fixup",
 188                 offsetof(struct xenvif, rx_gso_checksum_fixup)
 189         },
 190 };
 191
 192 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 193 {
 194         switch (string_set) {
 195         case ETH_SS_STATS:
 196                 return ARRAY_SIZE(xenvif_stats);
 197         default:
 198                 return -EINVAL;
 199         }
 200 }
 201
 202 static void xenvif_get_ethtool_stats(struct net_device *dev,
 203                                      struct ethtool_stats *stats, u64 * data)
 204 {
 205         void *vif = netdev_priv(dev);
 206         int i;
 207
 208         for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 209                 data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
 210 }
 211
 212 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 213 {
 214         int i;
 215
 216         switch (stringset) {
 217         case ETH_SS_STATS:
 218                 for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 219                         memcpy(data + i * ETH_GSTRING_LEN,
 220                                xenvif_stats[i].name, ETH_GSTRING_LEN);
 221                 break;
 222         }
 223 }
 224
 225 static struct ethtool_ops xenvif_ethtool_ops = {
 226         .get_link       = ethtool_op_get_link,
 227
 228         .get_sset_count = xenvif_get_sset_count,
 229         .get_ethtool_stats = xenvif_get_ethtool_stats,
 230         .get_strings = xenvif_get_strings,
 231 };
 232
 233 static struct net_device_ops xenvif_netdev_ops = {
 234         .ndo_start_xmit = xenvif_start_xmit,
 235         .ndo_get_stats  = xenvif_get_stats,
 236         .ndo_open       = xenvif_open,
 237         .ndo_stop       = xenvif_close,
 238         .ndo_change_mtu = xenvif_change_mtu,
 239         .ndo_fix_features = xenvif_fix_features,
 240 };
 241
 242 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 243                             unsigned int handle)
 244 {
 245         int err;
 246         struct net_device *dev;
 247         struct xenvif *vif;
 248         char name[IFNAMSIZ] = {};
 249
 250         snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 251         dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
 252         if (dev == NULL) {
 253                 pr_warn("Could not allocate netdev\n");
 254                 return ERR_PTR(-ENOMEM);
 255         }
 256
 257         SET_NETDEV_DEV(dev, parent);
 258
 259         vif = netdev_priv(dev);
 260         vif->domid  = domid;
 261         vif->handle = handle;
 262         vif->netbk  = NULL;
 263         vif->can_sg = 1;
 264         vif->csum = 1;
 265         atomic_set(&vif->refcnt, 1);
 266         init_waitqueue_head(&vif->waiting_to_free);
 267         vif->dev = dev;
 268         INIT_LIST_HEAD(&vif->schedule_list);
 269         INIT_LIST_HEAD(&vif->notify_list);
 270
 271         vif->credit_bytes = vif->remaining_credit = ~0UL;
 272         vif->credit_usec  = 0UL;
 273         init_timer(&vif->credit_timeout);
 274         /* Initialize 'expires' now: it's used to track the credit window. */
 275         vif->credit_timeout.expires = jiffies;
 276
 277         dev->netdev_ops = &xenvif_netdev_ops;
 278         dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
 279         dev->features = dev->hw_features;
 280         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 281
 282         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 283
 284         /*
 285          * Initialise a dummy MAC address. We choose the numerically
 286          * largest non-broadcast address to prevent the address getting
 287          * stolen by an Ethernet bridge for STP purposes.
 288          * (FE:FF:FF:FF:FF:FF)
 289          */
 290         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 291         dev->dev_addr[0] &= ~0x01;
 292
 293         netif_carrier_off(dev);
 294
 295         err = register_netdev(dev);
 296         if (err) {
 297                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 298                 free_netdev(dev);
 299                 return ERR_PTR(err);
 300         }
 301
 302         netdev_dbg(dev, "Successfully created xenvif\n");
 303         return vif;
 304 }
 305
 306 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 307                    unsigned long rx_ring_ref, unsigned int evtchn)
 308 {
 309         int err = -ENOMEM;
 310
 311         /* Already connected through? */
 312         if (vif->irq)
 313                 return 0;
 314
 315         err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 316         if (err < 0)
 317                 goto err;
 318
 319         err = bind_interdomain_evtchn_to_irqhandler(
 320                 vif->domid, evtchn, xenvif_interrupt, 0,
 321                 vif->dev->name, vif);
 322         if (err < 0)
 323                 goto err_unmap;
 324         vif->irq = err;
 325         disable_irq(vif->irq);
 326
 327         xenvif_get(vif);
 328
 329         rtnl_lock();
 330         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 331                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 332         netdev_update_features(vif->dev);
 333         netif_carrier_on(vif->dev);
 334         if (netif_running(vif->dev))
 335                 xenvif_up(vif);
 336         rtnl_unlock();
 337
 338         return 0;
 339 err_unmap:
 340         xen_netbk_unmap_frontend_rings(vif);
 341 err:
 342         return err;
 343 }
 344
 345 void xenvif_disconnect(struct xenvif *vif)
 346 {
 347         struct net_device *dev = vif->dev;
 348         if (netif_carrier_ok(dev)) {
 349                 rtnl_lock();
 350                 netif_carrier_off(dev); /* discard queued packets */
 351                 if (netif_running(dev))
 352                         xenvif_down(vif);
 353                 rtnl_unlock();
 354                 xenvif_put(vif);
 355         }
 356
 357         atomic_dec(&vif->refcnt);
 358         wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
 359
 360         del_timer_sync(&vif->credit_timeout);
 361
 362         if (vif->irq)
 363                 unbind_from_irqhandler(vif->irq, vif);
 364
 365         unregister_netdev(vif->dev);
 366
 367         xen_netbk_unmap_frontend_rings(vif);
 368
 369         free_netdev(vif->dev);
 370 }