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         del_timer_sync(&vif->credit_timeout);
 136         xen_netbk_deschedule_xenvif(vif);
 137         xen_netbk_remove_xenvif(vif);
 138 }
 139
 140 static int xenvif_open(struct net_device *dev)
 141 {
 142         struct xenvif *vif = netdev_priv(dev);
 143         if (netif_carrier_ok(dev))
 144                 xenvif_up(vif);
 145         netif_start_queue(dev);
 146         return 0;
 147 }
 148
 149 static int xenvif_close(struct net_device *dev)
 150 {
 151         struct xenvif *vif = netdev_priv(dev);
 152         if (netif_carrier_ok(dev))
 153                 xenvif_down(vif);
 154         netif_stop_queue(dev);
 155         return 0;
 156 }
 157
 158 static int xenvif_change_mtu(struct net_device *dev, int mtu)
 159 {
 160         struct xenvif *vif = netdev_priv(dev);
 161         int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
 162
 163         if (mtu > max)
 164                 return -EINVAL;
 165         dev->mtu = mtu;
 166         return 0;
 167 }
 168
 169 static netdev_features_t xenvif_fix_features(struct net_device *dev,
 170         netdev_features_t features)
 171 {
 172         struct xenvif *vif = netdev_priv(dev);
 173
 174         if (!vif->can_sg)
 175                 features &= ~NETIF_F_SG;
 176         if (!vif->gso && !vif->gso_prefix)
 177                 features &= ~NETIF_F_TSO;
 178         if (!vif->csum)
 179                 features &= ~NETIF_F_IP_CSUM;
 180
 181         return features;
 182 }
 183
 184 static const struct xenvif_stat {
 185         char name[ETH_GSTRING_LEN];
 186         u16 offset;
 187 } xenvif_stats[] = {
 188         {
 189                 "rx_gso_checksum_fixup",
 190                 offsetof(struct xenvif, rx_gso_checksum_fixup)
 191         },
 192 };
 193
 194 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 195 {
 196         switch (string_set) {
 197         case ETH_SS_STATS:
 198                 return ARRAY_SIZE(xenvif_stats);
 199         default:
 200                 return -EINVAL;
 201         }
 202 }
 203
 204 static void xenvif_get_ethtool_stats(struct net_device *dev,
 205                                      struct ethtool_stats *stats, u64 * data)
 206 {
 207         void *vif = netdev_priv(dev);
 208         int i;
 209
 210         for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 211                 data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
 212 }
 213
 214 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 215 {
 216         int i;
 217
 218         switch (stringset) {
 219         case ETH_SS_STATS:
 220                 for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 221                         memcpy(data + i * ETH_GSTRING_LEN,
 222                                xenvif_stats[i].name, ETH_GSTRING_LEN);
 223                 break;
 224         }
 225 }
 226
 227 static const struct ethtool_ops xenvif_ethtool_ops = {
 228         .get_link       = ethtool_op_get_link,
 229
 230         .get_sset_count = xenvif_get_sset_count,
 231         .get_ethtool_stats = xenvif_get_ethtool_stats,
 232         .get_strings = xenvif_get_strings,
 233 };
 234
 235 static const struct net_device_ops xenvif_netdev_ops = {
 236         .ndo_start_xmit = xenvif_start_xmit,
 237         .ndo_get_stats  = xenvif_get_stats,
 238         .ndo_open       = xenvif_open,
 239         .ndo_stop       = xenvif_close,
 240         .ndo_change_mtu = xenvif_change_mtu,
 241         .ndo_fix_features = xenvif_fix_features,
 242 };
 243
 244 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 245                             unsigned int handle)
 246 {
 247         int err;
 248         struct net_device *dev;
 249         struct xenvif *vif;
 250         char name[IFNAMSIZ] = {};
 251
 252         snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 253         dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
 254         if (dev == NULL) {
 255                 pr_warn("Could not allocate netdev\n");
 256                 return ERR_PTR(-ENOMEM);
 257         }
 258
 259         SET_NETDEV_DEV(dev, parent);
 260
 261         vif = netdev_priv(dev);
 262         vif->domid  = domid;
 263         vif->handle = handle;
 264         vif->netbk  = NULL;
 265         vif->can_sg = 1;
 266         vif->csum = 1;
 267         atomic_set(&vif->refcnt, 1);
 268         init_waitqueue_head(&vif->waiting_to_free);
 269         vif->dev = dev;
 270         INIT_LIST_HEAD(&vif->schedule_list);
 271         INIT_LIST_HEAD(&vif->notify_list);
 272
 273         vif->credit_bytes = vif->remaining_credit = ~0UL;
 274         vif->credit_usec  = 0UL;
 275         init_timer(&vif->credit_timeout);
 276         vif->credit_window_start = get_jiffies_64();
 277
 278         dev->netdev_ops = &xenvif_netdev_ops;
 279         dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
 280         dev->features = dev->hw_features;
 281         SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
 282
 283         dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 284
 285         /*
 286          * Initialise a dummy MAC address. We choose the numerically
 287          * largest non-broadcast address to prevent the address getting
 288          * stolen by an Ethernet bridge for STP purposes.
 289          * (FE:FF:FF:FF:FF:FF)
 290          */
 291         memset(dev->dev_addr, 0xFF, ETH_ALEN);
 292         dev->dev_addr[0] &= ~0x01;
 293
 294         netif_carrier_off(dev);
 295
 296         err = register_netdev(dev);
 297         if (err) {
 298                 netdev_warn(dev, "Could not register device: err=%d\n", err);
 299                 free_netdev(dev);
 300                 return ERR_PTR(err);
 301         }
 302
 303         netdev_dbg(dev, "Successfully created xenvif\n");
 304         return vif;
 305 }
 306
 307 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
 308                    unsigned long rx_ring_ref, unsigned int evtchn)
 309 {
 310         int err = -ENOMEM;
 311
 312         /* Already connected through? */
 313         if (vif->irq)
 314                 return 0;
 315
 316         err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
 317         if (err < 0)
 318                 goto err;
 319
 320         err = bind_interdomain_evtchn_to_irqhandler(
 321                 vif->domid, evtchn, xenvif_interrupt, 0,
 322                 vif->dev->name, vif);
 323         if (err < 0)
 324                 goto err_unmap;
 325         vif->irq = err;
 326         disable_irq(vif->irq);
 327
 328         xenvif_get(vif);
 329
 330         rtnl_lock();
 331         if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 332                 dev_set_mtu(vif->dev, ETH_DATA_LEN);
 333         netdev_update_features(vif->dev);
 334         netif_carrier_on(vif->dev);
 335         if (netif_running(vif->dev))
 336                 xenvif_up(vif);
 337         rtnl_unlock();
 338
 339         return 0;
 340 err_unmap:
 341         xen_netbk_unmap_frontend_rings(vif);
 342 err:
 343         return err;
 344 }
 345
 346 void xenvif_carrier_off(struct xenvif *vif)
 347 {
 348         struct net_device *dev = vif->dev;
 349
 350         rtnl_lock();
 351         netif_carrier_off(dev); /* discard queued packets */
 352         if (netif_running(dev))
 353                 xenvif_down(vif);
 354         rtnl_unlock();
 355         xenvif_put(vif);
 356 }
 357
 358 void xenvif_disconnect(struct xenvif *vif)
 359 {
 360         if (netif_carrier_ok(vif->dev))
 361                 xenvif_carrier_off(vif);
 362
 363         atomic_dec(&vif->refcnt);
 364         wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
 365
 366         if (vif->irq)
 367                 unbind_from_irqhandler(vif->irq, vif);
 368
 369         unregister_netdev(vif->dev);
 370
 371         xen_netbk_unmap_frontend_rings(vif);
 372
 373         free_netdev(vif->dev);
 374 }