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xen-netfront.c
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/*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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 <net/tcp.h>
#include <linux/udp.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/page.h>
#include <xen/platform_pci.h>
#include <xen/grant_table.h>
#include <xen/interface/io/netif.h>
#include <xen/interface/memory.h>
#include <xen/interface/grant_table.h>
/* Module parameters */
static unsigned int xennet_max_queues;
module_param_named(max_queues, xennet_max_queues, uint, 0644);
MODULE_PARM_DESC(max_queues,
"Maximum number of queues per virtual interface");
static const struct ethtool_ops xennet_ethtool_ops;
struct netfront_cb {
int pull_to;
};
#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 __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
/* Minimum number of Rx slots (includes slot for GSO metadata). */
#define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
/* Queue name is interface name with "-qNNN" appended */
#define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
/* IRQ name is queue name with "-tx" or "-rx" appended */
#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
struct netfront_stats {
u64 packets;
u64 bytes;
struct u64_stats_sync syncp;
};
struct netfront_info;
struct netfront_queue {
unsigned int id; /* Queue ID, 0-based */
char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
struct netfront_info *info;
struct napi_struct napi;
/* Split event channels support, tx_* == rx_* when using
* single event channel.
*/
unsigned int tx_evtchn, rx_evtchn;
unsigned int tx_irq, rx_irq;
/* Only used when split event channels support is enabled */
char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
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 long link;
} tx_skbs[NET_TX_RING_SIZE];
grant_ref_t gref_tx_head;
grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
struct page *grant_tx_page[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;
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];
};
struct netfront_info {
struct list_head list;
struct net_device *netdev;
struct xenbus_device *xbdev;
/* Multi-queue support */
struct netfront_queue *queues;
/* Statistics */
struct netfront_stats __percpu *rx_stats;
struct netfront_stats __percpu *tx_stats;
atomic_t rx_gso_checksum_fixup;
};
struct netfront_rx_info {
struct xen_netif_rx_response rx;
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
};
static void skb_entry_set_link(union skb_entry *list, unsigned short id)
{
list->link = id;
}
static int skb_entry_is_link(const union skb_entry *list)
{
BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
return (unsigned long)list->skb < PAGE_OFFSET;
}
/*
* Access macros for acquiring freeing slots in tx_skbs[].
*/
static void add_id_to_freelist(unsigned *head, union skb_entry *list,
unsigned short id)
{
skb_entry_set_link(&list[id], *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_queue *queue,
RING_IDX ri)
{
int i = xennet_rxidx(ri);
struct sk_buff *skb = queue->rx_skbs[i];
queue->rx_skbs[i] = NULL;
return skb;
}
static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
RING_IDX ri)
{
int i = xennet_rxidx(ri);
grant_ref_t ref = queue->grant_rx_ref[i];
queue->grant_rx_ref[i] = GRANT_INVALID_REF;
return ref;
}
#ifdef CONFIG_SYSFS
static const struct attribute_group xennet_dev_group;
#endif
static bool xennet_can_sg(struct net_device *dev)
{
return dev->features & NETIF_F_SG;
}
static void rx_refill_timeout(unsigned long data)
{
struct netfront_queue *queue = (struct netfront_queue *)data;
napi_schedule(&queue->napi);
}
static int netfront_tx_slot_available(struct netfront_queue *queue)
{
return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
(NET_TX_RING_SIZE - MAX_SKB_FRAGS - 2);
}
static void xennet_maybe_wake_tx(struct netfront_queue *queue)
{
struct net_device *dev = queue->info->netdev;
struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
netfront_tx_slot_available(queue) &&
likely(netif_running(dev)))
netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
}
static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
{
struct sk_buff *skb;
struct page *page;
skb = __netdev_alloc_skb(queue->info->netdev,
RX_COPY_THRESHOLD + NET_IP_ALIGN,
GFP_ATOMIC | __GFP_NOWARN);
if (unlikely(!skb))
return NULL;
page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
if (!page) {
kfree_skb(skb);
return NULL;
}
skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
/* Align ip header to a 16 bytes boundary */
skb_reserve(skb, NET_IP_ALIGN);
skb->dev = queue->info->netdev;
return skb;
}
static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
{
RING_IDX req_prod = queue->rx.req_prod_pvt;
int notify;
if (unlikely(!netif_carrier_ok(queue->info->netdev)))
return;
for (req_prod = queue->rx.req_prod_pvt;
req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
req_prod++) {
struct sk_buff *skb;
unsigned short id;
grant_ref_t ref;
unsigned long pfn;
struct xen_netif_rx_request *req;
skb = xennet_alloc_one_rx_buffer(queue);
if (!skb)
break;
id = xennet_rxidx(req_prod);
BUG_ON(queue->rx_skbs[id]);
queue->rx_skbs[id] = skb;
ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
BUG_ON((signed short)ref < 0);
queue->grant_rx_ref[id] = ref;
pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
req = RING_GET_REQUEST(&queue->rx, req_prod);
gnttab_grant_foreign_access_ref(ref,
queue->info->xbdev->otherend_id,
pfn_to_mfn(pfn),
0);
req->id = id;
req->gref = ref;
}
queue->rx.req_prod_pvt = req_prod;
/* Not enough requests? Try again later. */
if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN) {
mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
return;
}
wmb(); /* barrier so backend seens requests */
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
if (notify)
notify_remote_via_irq(queue->rx_irq);
}
static int xennet_open(struct net_device *dev)
{
struct netfront_info *np = netdev_priv(dev);
unsigned int num_queues = dev->real_num_tx_queues;
unsigned int i = 0;
struct netfront_queue *queue = NULL;
for (i = 0; i < num_queues; ++i) {
queue = &np->queues[i];
napi_enable(&queue->napi);
spin_lock_bh(&queue->rx_lock);
if (netif_carrier_ok(dev)) {
xennet_alloc_rx_buffers(queue);
queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
napi_schedule(&queue->napi);
}
spin_unlock_bh(&queue->rx_lock);
}
netif_tx_start_all_queues(dev);
return 0;
}
static void xennet_tx_buf_gc(struct netfront_queue *queue)
{
RING_IDX cons, prod;
unsigned short id;
struct sk_buff *skb;
BUG_ON(!netif_carrier_ok(queue->info->netdev));
do {
prod = queue->tx.sring->rsp_prod;
rmb(); /* Ensure we see responses up to 'rp'. */
for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
struct xen_netif_tx_response *txrsp;
txrsp = RING_GET_RESPONSE(&queue->tx, cons);
if (txrsp->status == XEN_NETIF_RSP_NULL)
continue;
id = txrsp->id;
skb = queue->tx_skbs[id].skb;
if (unlikely(gnttab_query_foreign_access(
queue->grant_tx_ref[id]) != 0)) {
pr_alert("%s: warning -- grant still in use by backend domain\n",
__func__);
BUG();
}
gnttab_end_foreign_access_ref(
queue->grant_tx_ref[id], GNTMAP_readonly);
gnttab_release_grant_reference(
&queue->gref_tx_head, queue->grant_tx_ref[id]);
queue->grant_tx_ref[id] = GRANT_INVALID_REF;
queue->grant_tx_page[id] = NULL;
add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
dev_kfree_skb_irq(skb);
}
queue->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.
*/
queue->tx.sring->rsp_event =
prod + ((queue->tx.sring->req_prod - prod) >> 1) + 1;
mb(); /* update shared area */
} while ((cons == prod) && (prod != queue->tx.sring->rsp_prod));
xennet_maybe_wake_tx(queue);
}
static struct xen_netif_tx_request *xennet_make_one_txreq(
struct netfront_queue *queue, struct sk_buff *skb,
struct page *page, unsigned int offset, unsigned int len)
{
unsigned int id;
struct xen_netif_tx_request *tx;
grant_ref_t ref;
len = min_t(unsigned int, PAGE_SIZE - offset, len);
id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
BUG_ON((signed short)ref < 0);
gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
page_to_mfn(page), GNTMAP_readonly);
queue->tx_skbs[id].skb = skb;
queue->grant_tx_page[id] = page;
queue->grant_tx_ref[id] = ref;
tx->id = id;
tx->gref = ref;
tx->offset = offset;
tx->size = len;
tx->flags = 0;
return tx;
}
static struct xen_netif_tx_request *xennet_make_txreqs(
struct netfront_queue *queue, struct xen_netif_tx_request *tx,
struct sk_buff *skb, struct page *page,
unsigned int offset, unsigned int len)
{
/* Skip unused frames from start of page */
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
while (len) {
tx->flags |= XEN_NETTXF_more_data;
tx = xennet_make_one_txreq(queue, skb_get(skb),
page, offset, len);
page++;
offset = 0;
len -= tx->size;
}
return tx;
}
/*
* Count how many ring slots are required to send this skb. Each frag
* might be a compound page.
*/
static int xennet_count_skb_slots(struct sk_buff *skb)
{
int i, frags = skb_shinfo(skb)->nr_frags;
int pages;
pages = PFN_UP(offset_in_page(skb->data) + skb_headlen(skb));
for (i = 0; i < frags; i++) {
skb_frag_t *frag = skb_shinfo(skb)->frags + i;
unsigned long size = skb_frag_size(frag);
unsigned long offset = frag->page_offset;
/* Skip unused frames from start of page */
offset &= ~PAGE_MASK;
pages += PFN_UP(offset + size);
}
return pages;
}
static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
void *accel_priv, select_queue_fallback_t fallback)
{
unsigned int num_queues = dev->real_num_tx_queues;
u32 hash;
u16 queue_idx;
/* First, check if there is only one queue */
if (num_queues == 1) {
queue_idx = 0;
} else {
hash = skb_get_hash(skb);
queue_idx = hash % num_queues;
}
return queue_idx;
}
static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct netfront_info *np = netdev_priv(dev);
struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
struct xen_netif_tx_request *tx, *first_tx;
unsigned int i;
int notify;
int slots;
struct page *page;
unsigned int offset;
unsigned int len;
unsigned long flags;
struct netfront_queue *queue = NULL;
unsigned int num_queues = dev->real_num_tx_queues;
u16 queue_index;
/* Drop the packet if no queues are set up */
if (num_queues < 1)
goto drop;
/* Determine which queue to transmit this SKB on */
queue_index = skb_get_queue_mapping(skb);
queue = &np->queues[queue_index];
/* If skb->len is too big for wire format, drop skb and alert
* user about misconfiguration.
*/
if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
net_alert_ratelimited(
"xennet: skb->len = %u, too big for wire format\n",
skb->len);
goto drop;
}
slots = xennet_count_skb_slots(skb);
if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
slots, skb->len);
if (skb_linearize(skb))
goto drop;
}
page = virt_to_page(skb->data);
offset = offset_in_page(skb->data);
len = skb_headlen(skb);
spin_lock_irqsave(&queue->tx_lock, flags);
if (unlikely(!netif_carrier_ok(dev) ||
(slots > 1 && !xennet_can_sg(dev)) ||
netif_needs_gso(skb, netif_skb_features(skb)))) {
spin_unlock_irqrestore(&queue->tx_lock, flags);
goto drop;
}
/* First request for the linear area. */
first_tx = tx = xennet_make_one_txreq(queue, skb,
page, offset, len);
page++;
offset = 0;
len -= tx->size;
if (skb->ip_summed == CHECKSUM_PARTIAL)
/* local packet? */
tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
/* remote but checksummed. */
tx->flags |= XEN_NETTXF_data_validated;
/* Optional extra info after the first request. */
if (skb_shinfo(skb)->gso_size) {
struct xen_netif_extra_info *gso;
gso = (struct xen_netif_extra_info *)
RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
tx->flags |= XEN_NETTXF_extra_info;
gso->u.gso.size = skb_shinfo(skb)->gso_size;
gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
XEN_NETIF_GSO_TYPE_TCPV6 :
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;
}
/* Requests for the rest of the linear area. */
tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
/* Requests for all the frags. */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
tx = xennet_make_txreqs(queue, tx, skb,
skb_frag_page(frag), frag->page_offset,
skb_frag_size(frag));
}
/* First request has the packet length. */
first_tx->size = skb->len;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
if (notify)
notify_remote_via_irq(queue->tx_irq);
u64_stats_update_begin(&tx_stats->syncp);
tx_stats->bytes += skb->len;
tx_stats->packets++;
u64_stats_update_end(&tx_stats->syncp);
/* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
xennet_tx_buf_gc(queue);
if (!netfront_tx_slot_available(queue))
netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
spin_unlock_irqrestore(&queue->tx_lock, flags);
return NETDEV_TX_OK;
drop:
dev->stats.tx_dropped++;
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
static int xennet_close(struct net_device *dev)
{
struct netfront_info *np = netdev_priv(dev);
unsigned int num_queues = dev->real_num_tx_queues;
unsigned int i;
struct netfront_queue *queue;
netif_tx_stop_all_queues(np->netdev);
for (i = 0; i < num_queues; ++i) {
queue = &np->queues[i];
napi_disable(&queue->napi);
}
return 0;
}
static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
grant_ref_t ref)
{
int new = xennet_rxidx(queue->rx.req_prod_pvt);
BUG_ON(queue->rx_skbs[new]);
queue->rx_skbs[new] = skb;
queue->grant_rx_ref[new] = ref;
RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
queue->rx.req_prod_pvt++;
}
static int xennet_get_extras(struct netfront_queue *queue,
struct xen_netif_extra_info *extras,
RING_IDX rp)
{
struct xen_netif_extra_info *extra;
struct device *dev = &queue->info->netdev->dev;
RING_IDX cons = queue->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(&queue->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(queue, cons);
ref = xennet_get_rx_ref(queue, cons);
xennet_move_rx_slot(queue, skb, ref);
} while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
queue->rx.rsp_cons = cons;
return err;
}
static int xennet_get_responses(struct netfront_queue *queue,
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 = &queue->info->netdev->dev;
RING_IDX cons = queue->rx.rsp_cons;
struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
grant_ref_t ref = xennet_get_rx_ref(queue, cons);
int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
int slots = 1;
int err = 0;
unsigned long ret;
if (rx->flags & XEN_NETRXF_extra_info) {
err = xennet_get_extras(queue, extras, rp);
cons = queue->rx.rsp_cons;
}
for (;;) {
if (unlikely(rx->status < 0 ||
rx->offset + rx->status > PAGE_SIZE)) {
if (net_ratelimit())
dev_warn(dev, "rx->offset: %u, size: %d\n",
rx->offset, rx->status);
xennet_move_rx_slot(queue, 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 backend.
*/
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(&queue->gref_rx_head, ref);
__skb_queue_tail(list, skb);
next:
if (!(rx->flags & XEN_NETRXF_more_data))
break;
if (cons + slots == rp) {
if (net_ratelimit())
dev_warn(dev, "Need more slots\n");
err = -ENOENT;
break;
}
rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
skb = xennet_get_rx_skb(queue, cons + slots);
ref = xennet_get_rx_ref(queue, cons + slots);
slots++;
}
if (unlikely(slots > max)) {
if (net_ratelimit())
dev_warn(dev, "Too many slots\n");
err = -E2BIG;
}
if (unlikely(err))
queue->rx.rsp_cons = cons + slots;
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())
pr_warn("GSO size must not be zero\n");
return -EINVAL;
}
if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
if (net_ratelimit())
pr_warn("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 =
(gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
SKB_GSO_TCPV4 :
SKB_GSO_TCPV6;
/* 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_queue *queue,
struct sk_buff *skb,
struct sk_buff_head *list)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
RING_IDX cons = queue->rx.rsp_cons;
struct sk_buff *nskb;
while ((nskb = __skb_dequeue(list))) {
struct xen_netif_rx_response *rx =
RING_GET_RESPONSE(&queue->rx, ++cons);
skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
if (shinfo->nr_frags == MAX_SKB_FRAGS) {
unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
BUG_ON(pull_to <= skb_headlen(skb));
__pskb_pull_tail(skb, pull_to - skb_headlen(skb));
}
BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
rx->offset, rx->status, PAGE_SIZE);
skb_shinfo(nskb)->nr_frags = 0;
kfree_skb(nskb);
}
return cons;
}
static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
{
bool recalculate_partial_csum = false;
/*
* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
* peers can fail to set NETRXF_csum_blank when sending a GSO
* frame. In this case force the SKB to CHECKSUM_PARTIAL and
* recalculate the partial checksum.
*/
if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
struct netfront_info *np = netdev_priv(dev);
atomic_inc(&np->rx_gso_checksum_fixup);
skb->ip_summed = CHECKSUM_PARTIAL;
recalculate_partial_csum = true;
}
/* A non-CHECKSUM_PARTIAL SKB does not require setup. */
if (skb->ip_summed != CHECKSUM_PARTIAL)
return 0;
return skb_checksum_setup(skb, recalculate_partial_csum);
}
static int handle_incoming_queue(struct netfront_queue *queue,
struct sk_buff_head *rxq)
{
struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
int packets_dropped = 0;
struct sk_buff *skb;
while ((skb = __skb_dequeue(rxq)) != NULL) {
int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
if (pull_to > skb_headlen(skb))
__pskb_pull_tail(skb, pull_to - skb_headlen(skb));
/* Ethernet work: Delayed to here as it peeks the header. */
skb->protocol = eth_type_trans(skb, queue->info->netdev);
skb_reset_network_header(skb);
if (checksum_setup(queue->info->netdev, skb)) {
kfree_skb(skb);
packets_dropped++;
queue->info->netdev->stats.rx_errors++;
continue;
}
u64_stats_update_begin(&rx_stats->syncp);
rx_stats->packets++;
rx_stats->bytes += skb->len;
u64_stats_update_end(&rx_stats->syncp);
/* Pass it up. */
napi_gro_receive(&queue->napi, skb);
}
return packets_dropped;
}
static int xennet_poll(struct napi_struct *napi, int budget)
{
struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
struct net_device *dev = queue->info->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;
int err;
spin_lock(&queue->rx_lock);
skb_queue_head_init(&rxq);
skb_queue_head_init(&errq);
skb_queue_head_init(&tmpq);
rp = queue->rx.sring->rsp_prod;
rmb(); /* Ensure we see queued responses up to 'rp'. */
i = queue->rx.rsp_cons;
work_done = 0;
while ((i != rp) && (work_done < budget)) {
memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
memset(extras, 0, sizeof(rinfo.extras));
err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
if (unlikely(err)) {
err:
while ((skb = __skb_dequeue(&tmpq)))
__skb_queue_tail(&errq, skb);
dev->stats.rx_errors++;
i = queue->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);
queue->rx.rsp_cons += skb_queue_len(&tmpq);
goto err;
}
}
NETFRONT_SKB_CB(skb)->pull_to = rx->status;
if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
skb_shinfo(skb)->frags[0].page_offset = rx->offset;
skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
skb->data_len = rx->status;
skb->len += rx->status;
i = xennet_fill_frags(queue, skb, &tmpq);
if (rx->flags & XEN_NETRXF_csum_blank)
skb->ip_summed = CHECKSUM_PARTIAL;
else if (rx->flags & XEN_NETRXF_data_validated)
skb->ip_summed = CHECKSUM_UNNECESSARY;
__skb_queue_tail(&rxq, skb);
queue->rx.rsp_cons = ++i;
work_done++;
}
__skb_queue_purge(&errq);
work_done -= handle_incoming_queue(queue, &rxq);
xennet_alloc_rx_buffers(queue);
if (work_done < budget) {
int more_to_do = 0;
napi_complete(napi);
RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
if (more_to_do)
napi_schedule(napi);