Logo Search packages:      
Sourcecode: linux version File versions  Download package

xen-netfront.c

/*
 * Virtual network driver for conversing with remote driver backends.
 *
 * Copyright (c) 2002-2005, K A Fraser
 * 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 version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/ethtool.h>
#include <linux/if_ether.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
#include <net/ip.h>

#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/page.h>
#include <xen/grant_table.h>

#include <xen/interface/io/netif.h>
#include <xen/interface/memory.h>
#include <xen/interface/grant_table.h>

static struct ethtool_ops xennet_ethtool_ops;

struct netfront_cb {
      struct page *page;
      unsigned offset;
};

#define NETFRONT_SKB_CB(skb)  ((struct netfront_cb *)((skb)->cb))

#define RX_COPY_THRESHOLD 256

#define GRANT_INVALID_REF     0

#define NET_TX_RING_SIZE __RING_SIZE((struct xen_netif_tx_sring *)0, PAGE_SIZE)
#define NET_RX_RING_SIZE __RING_SIZE((struct xen_netif_rx_sring *)0, PAGE_SIZE)
#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)

struct netfront_info {
      struct list_head list;
      struct net_device *netdev;

      struct napi_struct napi;

      unsigned int evtchn;
      struct xenbus_device *xbdev;

      spinlock_t   tx_lock;
      struct xen_netif_tx_front_ring tx;
      int tx_ring_ref;

      /*
       * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
       * are linked from tx_skb_freelist through skb_entry.link.
       *
       *  NB. Freelist index entries are always going to be less than
       *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
       *  greater than PAGE_OFFSET: we use this property to distinguish
       *  them.
       */
      union skb_entry {
            struct sk_buff *skb;
            unsigned link;
      } tx_skbs[NET_TX_RING_SIZE];
      grant_ref_t gref_tx_head;
      grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
      unsigned tx_skb_freelist;

      spinlock_t   rx_lock ____cacheline_aligned_in_smp;
      struct xen_netif_rx_front_ring rx;
      int rx_ring_ref;

      /* Receive-ring batched refills. */
#define RX_MIN_TARGET 8
#define RX_DFL_MIN_TARGET 64
#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
      unsigned rx_min_target, rx_max_target, rx_target;
      struct sk_buff_head rx_batch;

      struct timer_list rx_refill_timer;

      struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
      grant_ref_t gref_rx_head;
      grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];

      unsigned long rx_pfn_array[NET_RX_RING_SIZE];
      struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
      struct mmu_update rx_mmu[NET_RX_RING_SIZE];
};

struct netfront_rx_info {
      struct xen_netif_rx_response rx;
      struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
};

/*
 * Access macros for acquiring freeing slots in tx_skbs[].
 */

static void add_id_to_freelist(unsigned *head, union skb_entry *list,
                         unsigned short id)
{
      list[id].link = *head;
      *head = id;
}

static unsigned short get_id_from_freelist(unsigned *head,
                                 union skb_entry *list)
{
      unsigned int id = *head;
      *head = list[id].link;
      return id;
}

static int xennet_rxidx(RING_IDX idx)
{
      return idx & (NET_RX_RING_SIZE - 1);
}

static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
                               RING_IDX ri)
{
      int i = xennet_rxidx(ri);
      struct sk_buff *skb = np->rx_skbs[i];
      np->rx_skbs[i] = NULL;
      return skb;
}

static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
                                  RING_IDX ri)
{
      int i = xennet_rxidx(ri);
      grant_ref_t ref = np->grant_rx_ref[i];
      np->grant_rx_ref[i] = GRANT_INVALID_REF;
      return ref;
}

#ifdef CONFIG_SYSFS
static int xennet_sysfs_addif(struct net_device *netdev);
static void xennet_sysfs_delif(struct net_device *netdev);
#else /* !CONFIG_SYSFS */
#define xennet_sysfs_addif(dev) (0)
#define xennet_sysfs_delif(dev) do { } while (0)
#endif

static int xennet_can_sg(struct net_device *dev)
{
      return dev->features & NETIF_F_SG;
}


static void rx_refill_timeout(unsigned long data)
{
      struct net_device *dev = (struct net_device *)data;
      struct netfront_info *np = netdev_priv(dev);
      netif_rx_schedule(dev, &np->napi);
}

static int netfront_tx_slot_available(struct netfront_info *np)
{
      return ((np->tx.req_prod_pvt - np->tx.rsp_cons) <
            (TX_MAX_TARGET - MAX_SKB_FRAGS - 2));
}

static void xennet_maybe_wake_tx(struct net_device *dev)
{
      struct netfront_info *np = netdev_priv(dev);

      if (unlikely(netif_queue_stopped(dev)) &&
          netfront_tx_slot_available(np) &&
          likely(netif_running(dev)))
            netif_wake_queue(dev);
}

static void xennet_alloc_rx_buffers(struct net_device *dev)
{
      unsigned short id;
      struct netfront_info *np = netdev_priv(dev);
      struct sk_buff *skb;
      struct page *page;
      int i, batch_target, notify;
      RING_IDX req_prod = np->rx.req_prod_pvt;
      grant_ref_t ref;
      unsigned long pfn;
      void *vaddr;
      struct xen_netif_rx_request *req;

      if (unlikely(!netif_carrier_ok(dev)))
            return;

      /*
       * Allocate skbuffs greedily, even though we batch updates to the
       * receive ring. This creates a less bursty demand on the memory
       * allocator, so should reduce the chance of failed allocation requests
       * both for ourself and for other kernel subsystems.
       */
      batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
      for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
            skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD,
                               GFP_ATOMIC | __GFP_NOWARN);
            if (unlikely(!skb))
                  goto no_skb;

            page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
            if (!page) {
                  kfree_skb(skb);
no_skb:
                  /* Any skbuffs queued for refill? Force them out. */
                  if (i != 0)
                        goto refill;
                  /* Could not allocate any skbuffs. Try again later. */
                  mod_timer(&np->rx_refill_timer,
                          jiffies + (HZ/10));
                  break;
            }

            skb_shinfo(skb)->frags[0].page = page;
            skb_shinfo(skb)->nr_frags = 1;
            __skb_queue_tail(&np->rx_batch, skb);
      }

      /* Is the batch large enough to be worthwhile? */
      if (i < (np->rx_target/2)) {
            if (req_prod > np->rx.sring->req_prod)
                  goto push;
            return;
      }

      /* Adjust our fill target if we risked running out of buffers. */
      if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
          ((np->rx_target *= 2) > np->rx_max_target))
            np->rx_target = np->rx_max_target;

 refill:
      for (i = 0; ; i++) {
            skb = __skb_dequeue(&np->rx_batch);
            if (skb == NULL)
                  break;

            skb->dev = dev;

            id = xennet_rxidx(req_prod + i);

            BUG_ON(np->rx_skbs[id]);
            np->rx_skbs[id] = skb;

            ref = gnttab_claim_grant_reference(&np->gref_rx_head);
            BUG_ON((signed short)ref < 0);
            np->grant_rx_ref[id] = ref;

            pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page);
            vaddr = page_address(skb_shinfo(skb)->frags[0].page);

            req = RING_GET_REQUEST(&np->rx, req_prod + i);
            gnttab_grant_foreign_access_ref(ref,
                                    np->xbdev->otherend_id,
                                    pfn_to_mfn(pfn),
                                    0);

            req->id = id;
            req->gref = ref;
      }

      wmb();            /* barrier so backend seens requests */

      /* Above is a suitable barrier to ensure backend will see requests. */
      np->rx.req_prod_pvt = req_prod + i;
 push:
      RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
      if (notify)
            notify_remote_via_irq(np->netdev->irq);
}

static int xennet_open(struct net_device *dev)
{
      struct netfront_info *np = netdev_priv(dev);

      napi_enable(&np->napi);

      spin_lock_bh(&np->rx_lock);
      if (netif_carrier_ok(dev)) {
            xennet_alloc_rx_buffers(dev);
            np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
            if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
                  netif_rx_schedule(dev, &np->napi);
      }
      spin_unlock_bh(&np->rx_lock);

      xennet_maybe_wake_tx(dev);

      return 0;
}

static void xennet_tx_buf_gc(struct net_device *dev)
{
      RING_IDX cons, prod;
      unsigned short id;
      struct netfront_info *np = netdev_priv(dev);
      struct sk_buff *skb;

      BUG_ON(!netif_carrier_ok(dev));

      do {
            prod = np->tx.sring->rsp_prod;
            rmb(); /* Ensure we see responses up to 'rp'. */

            for (cons = np->tx.rsp_cons; cons != prod; cons++) {
                  struct xen_netif_tx_response *txrsp;

                  txrsp = RING_GET_RESPONSE(&np->tx, cons);
                  if (txrsp->status == NETIF_RSP_NULL)
                        continue;

                  id  = txrsp->id;
                  skb = np->tx_skbs[id].skb;
                  if (unlikely(gnttab_query_foreign_access(
                        np->grant_tx_ref[id]) != 0)) {
                        printk(KERN_ALERT "xennet_tx_buf_gc: warning "
                               "-- grant still in use by backend "
                               "domain.\n");
                        BUG();
                  }
                  gnttab_end_foreign_access_ref(
                        np->grant_tx_ref[id], GNTMAP_readonly);
                  gnttab_release_grant_reference(
                        &np->gref_tx_head, np->grant_tx_ref[id]);
                  np->grant_tx_ref[id] = GRANT_INVALID_REF;
                  add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
                  dev_kfree_skb_irq(skb);
            }

            np->tx.rsp_cons = prod;

            /*
             * Set a new event, then check for race with update of tx_cons.
             * Note that it is essential to schedule a callback, no matter
             * how few buffers are pending. Even if there is space in the
             * transmit ring, higher layers may be blocked because too much
             * data is outstanding: in such cases notification from Xen is
             * likely to be the only kick that we'll get.
             */
            np->tx.sring->rsp_event =
                  prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
            mb();       /* update shared area */
      } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));

      xennet_maybe_wake_tx(dev);
}

static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
                        struct xen_netif_tx_request *tx)
{
      struct netfront_info *np = netdev_priv(dev);
      char *data = skb->data;
      unsigned long mfn;
      RING_IDX prod = np->tx.req_prod_pvt;
      int frags = skb_shinfo(skb)->nr_frags;
      unsigned int offset = offset_in_page(data);
      unsigned int len = skb_headlen(skb);
      unsigned int id;
      grant_ref_t ref;
      int i;

      /* While the header overlaps a page boundary (including being
         larger than a page), split it it into page-sized chunks. */
      while (len > PAGE_SIZE - offset) {
            tx->size = PAGE_SIZE - offset;
            tx->flags |= NETTXF_more_data;
            len -= tx->size;
            data += tx->size;
            offset = 0;

            id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
            np->tx_skbs[id].skb = skb_get(skb);
            tx = RING_GET_REQUEST(&np->tx, prod++);
            tx->id = id;
            ref = gnttab_claim_grant_reference(&np->gref_tx_head);
            BUG_ON((signed short)ref < 0);

            mfn = virt_to_mfn(data);
            gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
                                    mfn, GNTMAP_readonly);

            tx->gref = np->grant_tx_ref[id] = ref;
            tx->offset = offset;
            tx->size = len;
            tx->flags = 0;
      }

      /* Grant backend access to each skb fragment page. */
      for (i = 0; i < frags; i++) {
            skb_frag_t *frag = skb_shinfo(skb)->frags + i;

            tx->flags |= NETTXF_more_data;

            id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
            np->tx_skbs[id].skb = skb_get(skb);
            tx = RING_GET_REQUEST(&np->tx, prod++);
            tx->id = id;
            ref = gnttab_claim_grant_reference(&np->gref_tx_head);
            BUG_ON((signed short)ref < 0);

            mfn = pfn_to_mfn(page_to_pfn(frag->page));
            gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
                                    mfn, GNTMAP_readonly);

            tx->gref = np->grant_tx_ref[id] = ref;
            tx->offset = frag->page_offset;
            tx->size = frag->size;
            tx->flags = 0;
      }

      np->tx.req_prod_pvt = prod;
}

static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
      unsigned short id;
      struct netfront_info *np = netdev_priv(dev);
      struct xen_netif_tx_request *tx;
      struct xen_netif_extra_info *extra;
      char *data = skb->data;
      RING_IDX i;
      grant_ref_t ref;
      unsigned long mfn;
      int notify;
      int frags = skb_shinfo(skb)->nr_frags;
      unsigned int offset = offset_in_page(data);
      unsigned int len = skb_headlen(skb);

      frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE;
      if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
            printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
                   frags);
            dump_stack();
            goto drop;
      }

      spin_lock_irq(&np->tx_lock);

      if (unlikely(!netif_carrier_ok(dev) ||
                 (frags > 1 && !xennet_can_sg(dev)) ||
                 netif_needs_gso(dev, skb))) {
            spin_unlock_irq(&np->tx_lock);
            goto drop;
      }

      i = np->tx.req_prod_pvt;

      id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
      np->tx_skbs[id].skb = skb;

      tx = RING_GET_REQUEST(&np->tx, i);

      tx->id   = id;
      ref = gnttab_claim_grant_reference(&np->gref_tx_head);
      BUG_ON((signed short)ref < 0);
      mfn = virt_to_mfn(data);
      gnttab_grant_foreign_access_ref(
            ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
      tx->gref = np->grant_tx_ref[id] = ref;
      tx->offset = offset;
      tx->size = len;
      extra = NULL;

      tx->flags = 0;
      if (skb->ip_summed == CHECKSUM_PARTIAL)
            /* local packet? */
            tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
      else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
            /* remote but checksummed. */
            tx->flags |= NETTXF_data_validated;

      if (skb_shinfo(skb)->gso_size) {
            struct xen_netif_extra_info *gso;

            gso = (struct xen_netif_extra_info *)
                  RING_GET_REQUEST(&np->tx, ++i);

            if (extra)
                  extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
            else
                  tx->flags |= NETTXF_extra_info;

            gso->u.gso.size = skb_shinfo(skb)->gso_size;
            gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
            gso->u.gso.pad = 0;
            gso->u.gso.features = 0;

            gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
            gso->flags = 0;
            extra = gso;
      }

      np->tx.req_prod_pvt = i + 1;

      xennet_make_frags(skb, dev, tx);
      tx->size = skb->len;

      RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
      if (notify)
            notify_remote_via_irq(np->netdev->irq);

      dev->stats.tx_bytes += skb->len;
      dev->stats.tx_packets++;

      /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
      xennet_tx_buf_gc(dev);

      if (!netfront_tx_slot_available(np))
            netif_stop_queue(dev);

      spin_unlock_irq(&np->tx_lock);

      return 0;

 drop:
      dev->stats.tx_dropped++;
      dev_kfree_skb(skb);
      return 0;
}

static int xennet_close(struct net_device *dev)
{
      struct netfront_info *np = netdev_priv(dev);
      netif_stop_queue(np->netdev);
      napi_disable(&np->napi);
      return 0;
}

static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
                        grant_ref_t ref)
{
      int new = xennet_rxidx(np->rx.req_prod_pvt);

      BUG_ON(np->rx_skbs[new]);
      np->rx_skbs[new] = skb;
      np->grant_rx_ref[new] = ref;
      RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
      RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
      np->rx.req_prod_pvt++;
}

static int xennet_get_extras(struct netfront_info *np,
                       struct xen_netif_extra_info *extras,
                       RING_IDX rp)

{
      struct xen_netif_extra_info *extra;
      struct device *dev = &np->netdev->dev;
      RING_IDX cons = np->rx.rsp_cons;
      int err = 0;

      do {
            struct sk_buff *skb;
            grant_ref_t ref;

            if (unlikely(cons + 1 == rp)) {
                  if (net_ratelimit())
                        dev_warn(dev, "Missing extra info\n");
                  err = -EBADR;
                  break;
            }

            extra = (struct xen_netif_extra_info *)
                  RING_GET_RESPONSE(&np->rx, ++cons);

            if (unlikely(!extra->type ||
                       extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
                  if (net_ratelimit())
                        dev_warn(dev, "Invalid extra type: %d\n",
                              extra->type);
                  err = -EINVAL;
            } else {
                  memcpy(&extras[extra->type - 1], extra,
                         sizeof(*extra));
            }

            skb = xennet_get_rx_skb(np, cons);
            ref = xennet_get_rx_ref(np, cons);
            xennet_move_rx_slot(np, skb, ref);
      } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);

      np->rx.rsp_cons = cons;
      return err;
}

static int xennet_get_responses(struct netfront_info *np,
                        struct netfront_rx_info *rinfo, RING_IDX rp,
                        struct sk_buff_head *list)
{
      struct xen_netif_rx_response *rx = &rinfo->rx;
      struct xen_netif_extra_info *extras = rinfo->extras;
      struct device *dev = &np->netdev->dev;
      RING_IDX cons = np->rx.rsp_cons;
      struct sk_buff *skb = xennet_get_rx_skb(np, cons);
      grant_ref_t ref = xennet_get_rx_ref(np, cons);
      int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
      int frags = 1;
      int err = 0;
      unsigned long ret;

      if (rx->flags & NETRXF_extra_info) {
            err = xennet_get_extras(np, extras, rp);
            cons = np->rx.rsp_cons;
      }

      for (;;) {
            if (unlikely(rx->status < 0 ||
                       rx->offset + rx->status > PAGE_SIZE)) {
                  if (net_ratelimit())
                        dev_warn(dev, "rx->offset: %x, size: %u\n",
                               rx->offset, rx->status);
                  xennet_move_rx_slot(np, skb, ref);
                  err = -EINVAL;
                  goto next;
            }

            /*
             * This definitely indicates a bug, either in this driver or in
             * the backend driver. In future this should flag the bad
             * situation to the system controller to reboot the backed.
             */
            if (ref == GRANT_INVALID_REF) {
                  if (net_ratelimit())
                        dev_warn(dev, "Bad rx response id %d.\n",
                               rx->id);
                  err = -EINVAL;
                  goto next;
            }

            ret = gnttab_end_foreign_access_ref(ref, 0);
            BUG_ON(!ret);

            gnttab_release_grant_reference(&np->gref_rx_head, ref);

            __skb_queue_tail(list, skb);

next:
            if (!(rx->flags & NETRXF_more_data))
                  break;

            if (cons + frags == rp) {
                  if (net_ratelimit())
                        dev_warn(dev, "Need more frags\n");
                  err = -ENOENT;
                  break;
            }

            rx = RING_GET_RESPONSE(&np->rx, cons + frags);
            skb = xennet_get_rx_skb(np, cons + frags);
            ref = xennet_get_rx_ref(np, cons + frags);
            frags++;
      }

      if (unlikely(frags > max)) {
            if (net_ratelimit())
                  dev_warn(dev, "Too many frags\n");
            err = -E2BIG;
      }

      if (unlikely(err))
            np->rx.rsp_cons = cons + frags;

      return err;
}

static int xennet_set_skb_gso(struct sk_buff *skb,
                        struct xen_netif_extra_info *gso)
{
      if (!gso->u.gso.size) {
            if (net_ratelimit())
                  printk(KERN_WARNING "GSO size must not be zero.\n");
            return -EINVAL;
      }

      /* Currently only TCPv4 S.O. is supported. */
      if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
            if (net_ratelimit())
                  printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
            return -EINVAL;
      }

      skb_shinfo(skb)->gso_size = gso->u.gso.size;
      skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;

      /* Header must be checked, and gso_segs computed. */
      skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
      skb_shinfo(skb)->gso_segs = 0;

      return 0;
}

static RING_IDX xennet_fill_frags(struct netfront_info *np,
                          struct sk_buff *skb,
                          struct sk_buff_head *list)
{
      struct skb_shared_info *shinfo = skb_shinfo(skb);
      int nr_frags = shinfo->nr_frags;
      RING_IDX cons = np->rx.rsp_cons;
      skb_frag_t *frag = shinfo->frags + nr_frags;
      struct sk_buff *nskb;

      while ((nskb = __skb_dequeue(list))) {
            struct xen_netif_rx_response *rx =
                  RING_GET_RESPONSE(&np->rx, ++cons);

            frag->page = skb_shinfo(nskb)->frags[0].page;
            frag->page_offset = rx->offset;
            frag->size = rx->status;

            skb->data_len += rx->status;

            skb_shinfo(nskb)->nr_frags = 0;
            kfree_skb(nskb);

            frag++;
            nr_frags++;
      }

      shinfo->nr_frags = nr_frags;
      return cons;
}

static int skb_checksum_setup(struct sk_buff *skb)
{
      struct iphdr *iph;
      unsigned char *th;
      int err = -EPROTO;

      if (skb->protocol != htons(ETH_P_IP))
            goto out;

      iph = (void *)skb->data;
      th = skb->data + 4 * iph->ihl;
      if (th >= skb_tail_pointer(skb))
            goto out;

      skb->csum_start = th - skb->head;
      switch (iph->protocol) {
      case IPPROTO_TCP:
            skb->csum_offset = offsetof(struct tcphdr, check);
            break;
      case IPPROTO_UDP:
            skb->csum_offset = offsetof(struct udphdr, check);
            break;
      default:
            if (net_ratelimit())
                  printk(KERN_ERR "Attempting to checksum a non-"
                         "TCP/UDP packet, dropping a protocol"
                         " %d packet", iph->protocol);
            goto out;
      }

      if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
            goto out;

      err = 0;

out:
      return err;
}

static int handle_incoming_queue(struct net_device *dev,
                         struct sk_buff_head *rxq)
{
      int packets_dropped = 0;
      struct sk_buff *skb;

      while ((skb = __skb_dequeue(rxq)) != NULL) {
            struct page *page = NETFRONT_SKB_CB(skb)->page;
            void *vaddr = page_address(page);
            unsigned offset = NETFRONT_SKB_CB(skb)->offset;

            memcpy(skb->data, vaddr + offset,
                   skb_headlen(skb));

            if (page != skb_shinfo(skb)->frags[0].page)
                  __free_page(page);

            /* Ethernet work: Delayed to here as it peeks the header. */
            skb->protocol = eth_type_trans(skb, dev);

            if (skb->ip_summed == CHECKSUM_PARTIAL) {
                  if (skb_checksum_setup(skb)) {
                        kfree_skb(skb);
                        packets_dropped++;
                        dev->stats.rx_errors++;
                        continue;
                  }
            }

            dev->stats.rx_packets++;
            dev->stats.rx_bytes += skb->len;

            /* Pass it up. */
            netif_receive_skb(skb);
            dev->last_rx = jiffies;
      }

      return packets_dropped;
}

static int xennet_poll(struct napi_struct *napi, int budget)
{
      struct netfront_info *np = container_of(napi, struct netfront_info, napi);
      struct net_device *dev = np->netdev;
      struct sk_buff *skb;
      struct netfront_rx_info rinfo;
      struct xen_netif_rx_response *rx = &rinfo.rx;
      struct xen_netif_extra_info *extras = rinfo.extras;
      RING_IDX i, rp;
      int work_done;
      struct sk_buff_head rxq;
      struct sk_buff_head errq;
      struct sk_buff_head tmpq;
      unsigned long flags;
      unsigned int len;
      int err;

      spin_lock(&np->rx_lock);

      skb_queue_head_init(&rxq);
      skb_queue_head_init(&errq);
      skb_queue_head_init(&tmpq);

      rp = np->rx.sring->rsp_prod;
      rmb(); /* Ensure we see queued responses up to 'rp'. */

      i = np->rx.rsp_cons;
      work_done = 0;
      while ((i != rp) && (work_done < budget)) {
            memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
            memset(extras, 0, sizeof(rinfo.extras));

            err = xennet_get_responses(np, &rinfo, rp, &tmpq);

            if (unlikely(err)) {
err:
                  while ((skb = __skb_dequeue(&tmpq)))
                        __skb_queue_tail(&errq, skb);
                  dev->stats.rx_errors++;
                  i = np->rx.rsp_cons;
                  continue;
            }

            skb = __skb_dequeue(&tmpq);

            if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
                  struct xen_netif_extra_info *gso;
                  gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];

                  if (unlikely(xennet_set_skb_gso(skb, gso))) {
                        __skb_queue_head(&tmpq, skb);
                        np->rx.rsp_cons += skb_queue_len(&tmpq);
                        goto err;
                  }
            }

            NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page;
            NETFRONT_SKB_CB(skb)->offset = rx->offset;

            len = rx->status;
            if (len > RX_COPY_THRESHOLD)
                  len = RX_COPY_THRESHOLD;
            skb_put(skb, len);

            if (rx->status > len) {
                  skb_shinfo(skb)->frags[0].page_offset =
                        rx->offset + len;
                  skb_shinfo(skb)->frags[0].size = rx->status - len;
                  skb->data_len = rx->status - len;
            } else {
                  skb_shinfo(skb)->frags[0].page = NULL;
                  skb_shinfo(skb)->nr_frags = 0;
            }

            i = xennet_fill_frags(np, skb, &tmpq);

            /*
             * Truesize approximates the size of true data plus
             * any supervisor overheads. Adding hypervisor
             * overheads has been shown to significantly reduce
             * achievable bandwidth with the default receive
             * buffer size. It is therefore not wise to account
             * for it here.
             *
             * After alloc_skb(RX_COPY_THRESHOLD), truesize is set
             * to RX_COPY_THRESHOLD + the supervisor
             * overheads. Here, we add the size of the data pulled
             * in xennet_fill_frags().
             *
             * We also adjust for any unused space in the main
             * data area by subtracting (RX_COPY_THRESHOLD -
             * len). This is especially important with drivers
             * which split incoming packets into header and data,
             * using only 66 bytes of the main data area (see the
             * e1000 driver for example.)  On such systems,
             * without this last adjustement, our achievable
             * receive throughout using the standard receive
             * buffer size was cut by 25%(!!!).
             */
            skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
            skb->len += skb->data_len;

            if (rx->flags & NETRXF_csum_blank)
                  skb->ip_summed = CHECKSUM_PARTIAL;
            else if (rx->flags & NETRXF_data_validated)
                  skb->ip_summed = CHECKSUM_UNNECESSARY;

            __skb_queue_tail(&rxq, skb);

            np->rx.rsp_cons = ++i;
            work_done++;
      }

      while ((skb = __skb_dequeue(&errq)))
            kfree_skb(skb);

      work_done -= handle_incoming_queue(dev, &rxq);

      /* If we get a callback with very few responses, reduce fill target. */
      /* NB. Note exponential increase, linear decrease. */
      if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
           ((3*np->rx_target) / 4)) &&
          (--np->rx_target < np->rx_min_target))
            np->rx_target = np->rx_min_target;

      xennet_alloc_rx_buffers(dev);

      if (work_done < budget) {
            int more_to_do = 0;

            local_irq_save(flags);

            RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
            if (!more_to_do)
                  __netif_rx_complete(dev, napi);

            local_irq_restore(flags);
      }

      spin_unlock(&np->rx_lock);

      return work_done;
}

static int xennet_change_mtu(struct net_device *dev, int mtu)
{
      int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;

      if (mtu > max)
            return -EINVAL;
      dev->mtu = mtu;
      return 0;
}

static void xennet_release_tx_bufs(struct netfront_info *np)
{
      struct sk_buff *skb;
      int i;

      for (i = 0; i < NET_TX_RING_SIZE; i++) {
            /* Skip over entries which are actually freelist references */
            if ((unsigned long)np->tx_skbs[i].skb < PAGE_OFFSET)
                  continue;

            skb = np->tx_skbs[i].skb;
            gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
                                    GNTMAP_readonly);
            gnttab_release_grant_reference(&np->gref_tx_head,
                                     np->grant_tx_ref[i]);
            np->grant_tx_ref[i] = GRANT_INVALID_REF;
            add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
            dev_kfree_skb_irq(skb);
      }
}

static void xennet_release_rx_bufs(struct netfront_info *np)
{
      struct mmu_update      *mmu = np->rx_mmu;
      struct multicall_entry *mcl = np->rx_mcl;
      struct sk_buff_head free_list;
      struct sk_buff *skb;
      unsigned long mfn;
      int xfer = 0, noxfer = 0, unused = 0;
      int id, ref;

      dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
                   __func__);
      return;

      skb_queue_head_init(&free_list);

      spin_lock_bh(&np->rx_lock);

      for (id = 0; id < NET_RX_RING_SIZE; id++) {
            ref = np->grant_rx_ref[id];
            if (ref == GRANT_INVALID_REF) {
                  unused++;
                  continue;
            }

            skb = np->rx_skbs[id];
            mfn = gnttab_end_foreign_transfer_ref(ref);
            gnttab_release_grant_reference(&np->gref_rx_head, ref);
            np->grant_rx_ref[id] = GRANT_INVALID_REF;

            if (0 == mfn) {
                  skb_shinfo(skb)->nr_frags = 0;
                  dev_kfree_skb(skb);
                  noxfer++;
                  continue;
            }

            if (!xen_feature(XENFEAT_auto_translated_physmap)) {
                  /* Remap the page. */
                  struct page *page = skb_shinfo(skb)->frags[0].page;
                  unsigned long pfn = page_to_pfn(page);
                  void *vaddr = page_address(page);

                  MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
                                    mfn_pte(mfn, PAGE_KERNEL),
                                    0);
                  mcl++;
                  mmu->ptr = ((u64)mfn << PAGE_SHIFT)
                        | MMU_MACHPHYS_UPDATE;
                  mmu->val = pfn;
                  mmu++;

                  set_phys_to_machine(pfn, mfn);
            }
            __skb_queue_tail(&free_list, skb);
            xfer++;
      }

      dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
             __func__, xfer, noxfer, unused);

      if (xfer) {
            if (!xen_feature(XENFEAT_auto_translated_physmap)) {
                  /* Do all the remapping work and M2P updates. */
                  MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
                               0, DOMID_SELF);
                  mcl++;
                  HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
            }
      }

      while ((skb = __skb_dequeue(&free_list)) != NULL)
            dev_kfree_skb(skb);

      spin_unlock_bh(&np->rx_lock);
}

static void xennet_uninit(struct net_device *dev)
{
      struct netfront_info *np = netdev_priv(dev);
      xennet_release_tx_bufs(np);
      xennet_release_rx_bufs(np);
      gnttab_free_grant_references(np->gref_tx_head);
      gnttab_free_grant_references(np->gref_rx_head);
}

static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
{
      int i, err;
      struct net_device *netdev;
      struct netfront_info *np;

      netdev = alloc_etherdev(sizeof(struct netfront_info));
      if (!netdev) {
            printk(KERN_WARNING "%s> alloc_etherdev failed.\n",
                   __func__);
            return ERR_PTR(-ENOMEM);
      }

      np                   = netdev_priv(netdev);
      np->xbdev            = dev;

      spin_lock_init(&np->tx_lock);
      spin_lock_init(&np->rx_lock);

      skb_queue_head_init(&np->rx_batch);
      np->rx_target     = RX_DFL_MIN_TARGET;
      np->rx_min_target = RX_DFL_MIN_TARGET;
      np->rx_max_target = RX_MAX_TARGET;

      init_timer(&np->rx_refill_timer);
      np->rx_refill_timer.data = (unsigned long)netdev;
      np->rx_refill_timer.function = rx_refill_timeout;

      /* Initialise tx_skbs as a free chain containing every entry. */
      np->tx_skb_freelist = 0;
      for (i = 0; i < NET_TX_RING_SIZE; i++) {
            np->tx_skbs[i].link = i+1;
            np->grant_tx_ref[i] = GRANT_INVALID_REF;
      }

      /* Clear out rx_skbs */
      for (i = 0; i < NET_RX_RING_SIZE; i++) {
            np->rx_skbs[i] = NULL;
            np->grant_rx_ref[i] = GRANT_INVALID_REF;
      }

      /* A grant for every tx ring slot */
      if (gnttab_alloc_grant_references(TX_MAX_TARGET,
                                &np->gref_tx_head) < 0) {
            printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
            err = -ENOMEM;
            goto exit;
      }
      /* A grant for every rx ring slot */
      if (gnttab_alloc_grant_references(RX_MAX_TARGET,
                                &np->gref_rx_head) < 0) {
            printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
            err = -ENOMEM;
            goto exit_free_tx;
      }

      netdev->open            = xennet_open;
      netdev->hard_start_xmit = xennet_start_xmit;
      netdev->stop            = xennet_close;
      netif_napi_add(netdev, &np->napi, xennet_poll, 64);
      netdev->uninit          = xennet_uninit;
      netdev->change_mtu      = xennet_change_mtu;
      netdev->features        = NETIF_F_IP_CSUM;

      SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
      SET_NETDEV_DEV(netdev, &dev->dev);

      np->netdev = netdev;

      netif_carrier_off(netdev);

      return netdev;

 exit_free_tx:
      gnttab_free_grant_references(np->gref_tx_head);
 exit:
      free_netdev(netdev);
      return ERR_PTR(err);
}

/**
 * Entry point to this code when a new device is created.  Allocate the basic
 * structures and the ring buffers for communication with the backend, and
 * inform the backend of the appropriate details for those.
 */
static int __devinit netfront_probe(struct xenbus_device *dev,
                            const struct xenbus_device_id *id)
{
      int err;
      struct net_device *netdev;
      struct netfront_info *info;

      netdev = xennet_create_dev(dev);
      if (IS_ERR(netdev)) {
            err = PTR_ERR(netdev);
            xenbus_dev_fatal(dev, err, "creating netdev");
            return err;
      }

      info = netdev_priv(netdev);
      dev->dev.driver_data = info;

      err = register_netdev(info->netdev);
      if (err) {
            printk(KERN_WARNING "%s: register_netdev err=%d\n",
                   __func__, err);
            goto fail;
      }

      err = xennet_sysfs_addif(info->netdev);
      if (err) {
            unregister_netdev(info->netdev);
            printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
                   __func__, err);
            goto fail;
      }

      return 0;

 fail:
      free_netdev(netdev);
      dev->dev.driver_data = NULL;
      return err;
}

static void xennet_end_access(int ref, void *page)
{
      /* This frees the page as a side-effect */
      if (ref != GRANT_INVALID_REF)
            gnttab_end_foreign_access(ref, 0, (unsigned long)page);
}

static void xennet_disconnect_backend(struct netfront_info *info)
{
      /* Stop old i/f to prevent errors whilst we rebuild the state. */
      spin_lock_bh(&info->rx_lock);
      spin_lock_irq(&info->tx_lock);
      netif_carrier_off(info->netdev);
      spin_unlock_irq(&info->tx_lock);
      spin_unlock_bh(&info->rx_lock);

      if (info->netdev->irq)
            unbind_from_irqhandler(info->netdev->irq, info->netdev);
      info->evtchn = info->netdev->irq = 0;

      /* End access and free the pages */
      xennet_end_access(info->tx_ring_ref, info->tx.sring);
      xennet_end_access(info->rx_ring_ref, info->rx.sring);

      info->tx_ring_ref = GRANT_INVALID_REF;
      info->rx_ring_ref = GRANT_INVALID_REF;
      info->tx.sring = NULL;
      info->rx.sring = NULL;
}

/**
 * We are reconnecting to the backend, due to a suspend/resume, or a backend
 * driver restart.  We tear down our netif structure and recreate it, but
 * leave the device-layer structures intact so that this is transparent to the
 * rest of the kernel.
 */
static int netfront_resume(struct xenbus_device *dev)
{
      struct netfront_info *info = dev->dev.driver_data;

      dev_dbg(&dev->dev, "%s\n", dev->nodename);

      xennet_disconnect_backend(info);
      return 0;
}

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 irqreturn_t xennet_interrupt(int irq, void *dev_id)
{
      struct net_device *dev = dev_id;
      struct netfront_info *np = netdev_priv(dev);
      unsigned long flags;

      spin_lock_irqsave(&np->tx_lock, flags);

      if (likely(netif_carrier_ok(dev))) {
            xennet_tx_buf_gc(dev);
            /* Under tx_lock: protects access to rx shared-ring indexes. */
            if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
                  netif_rx_schedule(dev, &np->napi);
      }

      spin_unlock_irqrestore(&np->tx_lock, flags);

      return IRQ_HANDLED;
}

static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
{
      struct xen_netif_tx_sring *txs;
      struct xen_netif_rx_sring *rxs;
      int err;
      struct net_device *netdev = info->netdev;

      info->tx_ring_ref = GRANT_INVALID_REF;
      info->rx_ring_ref = GRANT_INVALID_REF;
      info->rx.sring = NULL;
      info->tx.sring = NULL;
      netdev->irq = 0;

      err = xen_net_read_mac(dev, netdev->dev_addr);
      if (err) {
            xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
            goto fail;
      }

      txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_KERNEL);
      if (!txs) {
            err = -ENOMEM;
            xenbus_dev_fatal(dev, err, "allocating tx ring page");
            goto fail;
      }
      SHARED_RING_INIT(txs);
      FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);

      err = xenbus_grant_ring(dev, virt_to_mfn(txs));
      if (err < 0) {
            free_page((unsigned long)txs);
            goto fail;
      }

      info->tx_ring_ref = err;
      rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_KERNEL);
      if (!rxs) {
            err = -ENOMEM;
            xenbus_dev_fatal(dev, err, "allocating rx ring page");
            goto fail;
      }
      SHARED_RING_INIT(rxs);
      FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);

      err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
      if (err < 0) {
            free_page((unsigned long)rxs);
            goto fail;
      }
      info->rx_ring_ref = err;

      err = xenbus_alloc_evtchn(dev, &info->evtchn);
      if (err)
            goto fail;

      err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
                              IRQF_SAMPLE_RANDOM, netdev->name,
                              netdev);
      if (err < 0)
            goto fail;
      netdev->irq = err;
      return 0;

 fail:
      return err;
}

/* Common code used when first setting up, and when resuming. */
static int talk_to_backend(struct xenbus_device *dev,
                     struct netfront_info *info)
{
      const char *message;
      struct xenbus_transaction xbt;
      int err;

      /* Create shared ring, alloc event channel. */
      err = setup_netfront(dev, info);
      if (err)
            goto out;

again:
      err = xenbus_transaction_start(&xbt);
      if (err) {
            xenbus_dev_fatal(dev, err, "starting transaction");
            goto destroy_ring;
      }

      err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
                      info->tx_ring_ref);
      if (err) {
            message = "writing tx ring-ref";
            goto abort_transaction;
      }
      err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
                      info->rx_ring_ref);
      if (err) {
            message = "writing rx ring-ref";
            goto abort_transaction;
      }
      err = xenbus_printf(xbt, dev->nodename,
                      "event-channel", "%u", info->evtchn);
      if (err) {
            message = "writing event-channel";
            goto abort_transaction;
      }

      err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
                      1);
      if (err) {
            message = "writing request-rx-copy";
            goto abort_transaction;
      }

      err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
      if (err) {
            message = "writing feature-rx-notify";
            goto abort_transaction;
      }

      err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
      if (err) {
            message = "writing feature-sg";
            goto abort_transaction;
      }

      err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
      if (err) {
            message = "writing feature-gso-tcpv4";
            goto abort_transaction;
      }

      err = xenbus_transaction_end(xbt, 0);
      if (err) {
            if (err == -EAGAIN)
                  goto again;
            xenbus_dev_fatal(dev, err, "completing transaction");
            goto destroy_ring;
      }

      return 0;

 abort_transaction:
      xenbus_transaction_end(xbt, 1);
      xenbus_dev_fatal(dev, err, "%s", message);
 destroy_ring:
      xennet_disconnect_backend(info);
 out:
      return err;
}

static int xennet_set_sg(struct net_device *dev, u32 data)
{
      if (data) {
            struct netfront_info *np = netdev_priv(dev);
            int val;

            if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
                         "%d", &val) < 0)
                  val = 0;
            if (!val)
                  return -ENOSYS;
      } else if (dev->mtu > ETH_DATA_LEN)
            dev->mtu = ETH_DATA_LEN;

      return ethtool_op_set_sg(dev, data);
}

static int xennet_set_tso(struct net_device *dev, u32 data)
{
      if (data) {
            struct netfront_info *np = netdev_priv(dev);
            int val;

            if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
                         "feature-gso-tcpv4", "%d", &val) < 0)
                  val = 0;
            if (!val)
                  return -ENOSYS;
      }

      return ethtool_op_set_tso(dev, data);
}

static void xennet_set_features(struct net_device *dev)
{
      /* Turn off all GSO bits except ROBUST. */
      dev->features &= (1 << NETIF_F_GSO_SHIFT) - 1;
      dev->features |= NETIF_F_GSO_ROBUST;
      xennet_set_sg(dev, 0);

      /* We need checksum offload to enable scatter/gather and TSO. */
      if (!(dev->features & NETIF_F_IP_CSUM))
            return;

      if (!xennet_set_sg(dev, 1))
            xennet_set_tso(dev, 1);
}

static int xennet_connect(struct net_device *dev)
{
      struct netfront_info *np = netdev_priv(dev);
      int i, requeue_idx, err;
      struct sk_buff *skb;
      grant_ref_t ref;
      struct xen_netif_rx_request *req;
      unsigned int feature_rx_copy;

      err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
                     "feature-rx-copy", "%u", &feature_rx_copy);
      if (err != 1)
            feature_rx_copy = 0;

      if (!feature_rx_copy) {
            dev_info(&dev->dev,
                   "backend does not support copying receive path\n");
            return -ENODEV;
      }

      err = talk_to_backend(np->xbdev, np);
      if (err)
            return err;

      xennet_set_features(dev);

      spin_lock_bh(&np->rx_lock);
      spin_lock_irq(&np->tx_lock);

      /* Step 1: Discard all pending TX packet fragments. */
      xennet_release_tx_bufs(np);

      /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
      for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
            if (!np->rx_skbs[i])
                  continue;

            skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
            ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
            req = RING_GET_REQUEST(&np->rx, requeue_idx);

            gnttab_grant_foreign_access_ref(
                  ref, np->xbdev->otherend_id,
                  pfn_to_mfn(page_to_pfn(skb_shinfo(skb)->
                                     frags->page)),
                  0);
            req->gref = ref;
            req->id   = requeue_idx;

            requeue_idx++;
      }

      np->rx.req_prod_pvt = requeue_idx;

      /*
       * Step 3: All public and private state should now be sane.  Get
       * ready to start sending and receiving packets and give the driver
       * domain a kick because we've probably just requeued some
       * packets.
       */
      netif_carrier_on(np->netdev);
      notify_remote_via_irq(np->netdev->irq);
      xennet_tx_buf_gc(dev);
      xennet_alloc_rx_buffers(dev);

      spin_unlock_irq(&np->tx_lock);
      spin_unlock_bh(&np->rx_lock);

      return 0;
}

/**
 * Callback received when the backend's state changes.
 */
static void backend_changed(struct xenbus_device *dev,
                      enum xenbus_state backend_state)
{
      struct netfront_info *np = dev->dev.driver_data;
      struct net_device *netdev = np->netdev;

      dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));

      switch (backend_state) {
      case XenbusStateInitialising:
      case XenbusStateInitialised:
      case XenbusStateConnected:
      case XenbusStateUnknown:
      case XenbusStateClosed:
            break;

      case XenbusStateInitWait:
            if (dev->state != XenbusStateInitialising)
                  break;
            if (xennet_connect(netdev) != 0)
                  break;
            xenbus_switch_state(dev, XenbusStateConnected);
            break;

      case XenbusStateClosing:
            xenbus_frontend_closed(dev);
            break;
      }
}

static struct ethtool_ops xennet_ethtool_ops =
{
      .set_tx_csum = ethtool_op_set_tx_csum,
      .set_sg = xennet_set_sg,
      .set_tso = xennet_set_tso,
      .get_link = ethtool_op_get_link,
};

#ifdef CONFIG_SYSFS
static ssize_t show_rxbuf_min(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
      struct net_device *netdev = to_net_dev(dev);
      struct netfront_info *info = netdev_priv(netdev);

      return sprintf(buf, "%u\n", info->rx_min_target);
}

static ssize_t store_rxbuf_min(struct device *dev,
                         struct device_attribute *attr,
                         const char *buf, size_t len)
{
      struct net_device *netdev = to_net_dev(dev);
      struct netfront_info *np = netdev_priv(netdev);
      char *endp;
      unsigned long target;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      target = simple_strtoul(buf, &endp, 0);
      if (endp == buf)
            return -EBADMSG;

      if (target < RX_MIN_TARGET)
            target = RX_MIN_TARGET;
      if (target > RX_MAX_TARGET)
            target = RX_MAX_TARGET;

      spin_lock_bh(&np->rx_lock);
      if (target > np->rx_max_target)
            np->rx_max_target = target;
      np->rx_min_target = target;
      if (target > np->rx_target)
            np->rx_target = target;

      xennet_alloc_rx_buffers(netdev);

      spin_unlock_bh(&np->rx_lock);
      return len;
}

static ssize_t show_rxbuf_max(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
      struct net_device *netdev = to_net_dev(dev);
      struct netfront_info *info = netdev_priv(netdev);

      return sprintf(buf, "%u\n", info->rx_max_target);
}

static ssize_t store_rxbuf_max(struct device *dev,
                         struct device_attribute *attr,
                         const char *buf, size_t len)
{
      struct net_device *netdev = to_net_dev(dev);
      struct netfront_info *np = netdev_priv(netdev);
      char *endp;
      unsigned long target;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      target = simple_strtoul(buf, &endp, 0);
      if (endp == buf)
            return -EBADMSG;

      if (target < RX_MIN_TARGET)
            target = RX_MIN_TARGET;
      if (target > RX_MAX_TARGET)
            target = RX_MAX_TARGET;

      spin_lock_bh(&np->rx_lock);
      if (target < np->rx_min_target)
            np->rx_min_target = target;
      np->rx_max_target = target;
      if (target < np->rx_target)
            np->rx_target = target;

      xennet_alloc_rx_buffers(netdev);

      spin_unlock_bh(&np->rx_lock);
      return len;
}

static ssize_t show_rxbuf_cur(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
      struct net_device *netdev = to_net_dev(dev);
      struct netfront_info *info = netdev_priv(netdev);

      return sprintf(buf, "%u\n", info->rx_target);
}

static struct device_attribute xennet_attrs[] = {
      __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
      __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
      __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
};

static int xennet_sysfs_addif(struct net_device *netdev)
{
      int i;
      int err;

      for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
            err = device_create_file(&netdev->dev,
                                 &xennet_attrs[i]);
            if (err)
                  goto fail;
      }
      return 0;

 fail:
      while (--i >= 0)
            device_remove_file(&netdev->dev, &xennet_attrs[i]);
      return err;
}

static void xennet_sysfs_delif(struct net_device *netdev)
{
      int i;

      for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
            device_remove_file(&netdev->dev, &xennet_attrs[i]);
}

#endif /* CONFIG_SYSFS */

static struct xenbus_device_id netfront_ids[] = {
      { "vif" },
      { "" }
};


static int __devexit xennet_remove(struct xenbus_device *dev)
{
      struct netfront_info *info = dev->dev.driver_data;

      dev_dbg(&dev->dev, "%s\n", dev->nodename);

      unregister_netdev(info->netdev);

      xennet_disconnect_backend(info);

      del_timer_sync(&info->rx_refill_timer);

      xennet_sysfs_delif(info->netdev);

      free_netdev(info->netdev);

      return 0;
}

static struct xenbus_driver netfront = {
      .name = "vif",
      .owner = THIS_MODULE,
      .ids = netfront_ids,
      .probe = netfront_probe,
      .remove = __devexit_p(xennet_remove),
      .resume = netfront_resume,
      .otherend_changed = backend_changed,
};

static int __init netif_init(void)
{
      if (!is_running_on_xen())
            return -ENODEV;

      if (is_initial_xendomain())
            return 0;

      printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");

      return xenbus_register_frontend(&netfront);
}
module_init(netif_init);


static void __exit netif_exit(void)
{
      if (is_initial_xendomain())
            return;

      return xenbus_unregister_driver(&netfront);
}
module_exit(netif_exit);

MODULE_DESCRIPTION("Xen virtual network device frontend");
MODULE_LICENSE("GPL");

Generated by  Doxygen 1.6.0   Back to index