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netback.c
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netback.c
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/*
* Back-end of the driver for virtual network devices. This portion of the
* driver exports a 'unified' network-device interface that can be accessed
* by any operating system that implements a compatible front end. A
* reference front-end implementation can be found in:
* drivers/net/xen-netfront.c
*
* Copyright (c) 2002-2005, K A Fraser
*
* 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 "common.h"
#include <linux/kthread.h>
#include <linux/if_vlan.h>
#include <linux/udp.h>
#include <linux/highmem.h>
#include <net/tcp.h>
#include <xen/xen.h>
#include <xen/events.h>
#include <xen/interface/memory.h>
#include <xen/page.h>
#include <asm/xen/hypercall.h>
/* Provide an option to disable split event channels at load time as
* event channels are limited resource. Split event channels are
* enabled by default.
*/
bool separate_tx_rx_irq = true;
module_param(separate_tx_rx_irq, bool, 0644);
/* The time that packets can stay on the guest Rx internal queue
* before they are dropped.
*/
unsigned int rx_drain_timeout_msecs = 10000;
module_param(rx_drain_timeout_msecs, uint, 0444);
/* The length of time before the frontend is considered unresponsive
* because it isn't providing Rx slots.
*/
unsigned int rx_stall_timeout_msecs = 60000;
module_param(rx_stall_timeout_msecs, uint, 0444);
#define MAX_QUEUES_DEFAULT 8
unsigned int xenvif_max_queues;
module_param_named(max_queues, xenvif_max_queues, uint, 0644);
MODULE_PARM_DESC(max_queues,
"Maximum number of queues per virtual interface");
/*
* This is the maximum slots a skb can have. If a guest sends a skb
* which exceeds this limit it is considered malicious.
*/
#define FATAL_SKB_SLOTS_DEFAULT 20
static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
module_param(fatal_skb_slots, uint, 0444);
/* The amount to copy out of the first guest Tx slot into the skb's
* linear area. If the first slot has more data, it will be mapped
* and put into the first frag.
*
* This is sized to avoid pulling headers from the frags for most
* TCP/IP packets.
*/
#define XEN_NETBACK_TX_COPY_LEN 128
/* This is the maximum number of flows in the hash cache. */
#define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
/* The module parameter tells that we have to put data
* for xen-netfront with the XDP_PACKET_HEADROOM offset
* needed for XDP processing
*/
bool provides_xdp_headroom = true;
module_param(provides_xdp_headroom, bool, 0644);
static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
u8 status);
static void make_tx_response(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp,
unsigned int extra_count,
s8 st);
static void push_tx_responses(struct xenvif_queue *queue);
static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
static inline int tx_work_todo(struct xenvif_queue *queue);
static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
u16 idx)
{
return page_to_pfn(queue->mmap_pages[idx]);
}
static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
u16 idx)
{
return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
}
#define callback_param(vif, pending_idx) \
(vif->pending_tx_info[pending_idx].callback_struct)
/* Find the containing VIF's structure from a pointer in pending_tx_info array
*/
static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info_msgzc *ubuf)
{
u16 pending_idx = ubuf->desc;
struct pending_tx_info *temp =
container_of(ubuf, struct pending_tx_info, callback_struct);
return container_of(temp - pending_idx,
struct xenvif_queue,
pending_tx_info[0]);
}
static u16 frag_get_pending_idx(skb_frag_t *frag)
{
return (u16)skb_frag_off(frag);
}
static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
{
skb_frag_off_set(frag, pending_idx);
}
static inline pending_ring_idx_t pending_index(unsigned i)
{
return i & (MAX_PENDING_REQS-1);
}
void xenvif_kick_thread(struct xenvif_queue *queue)
{
wake_up(&queue->wq);
}
void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
{
int more_to_do;
RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
if (more_to_do)
napi_schedule(&queue->napi);
else if (atomic_fetch_andnot(NETBK_TX_EOI | NETBK_COMMON_EOI,
&queue->eoi_pending) &
(NETBK_TX_EOI | NETBK_COMMON_EOI))
xen_irq_lateeoi(queue->tx_irq, 0);
}
static void tx_add_credit(struct xenvif_queue *queue)
{
unsigned long max_burst, max_credit;
/*
* Allow a burst big enough to transmit a jumbo packet of up to 128kB.
* Otherwise the interface can seize up due to insufficient credit.
*/
max_burst = max(131072UL, queue->credit_bytes);
/* Take care that adding a new chunk of credit doesn't wrap to zero. */
max_credit = queue->remaining_credit + queue->credit_bytes;
if (max_credit < queue->remaining_credit)
max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
queue->remaining_credit = min(max_credit, max_burst);
queue->rate_limited = false;
}
void xenvif_tx_credit_callback(struct timer_list *t)
{
struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
tx_add_credit(queue);
xenvif_napi_schedule_or_enable_events(queue);
}
static void xenvif_tx_err(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp,
unsigned int extra_count, RING_IDX end)
{
RING_IDX cons = queue->tx.req_cons;
unsigned long flags;
do {
spin_lock_irqsave(&queue->response_lock, flags);
make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
push_tx_responses(queue);
spin_unlock_irqrestore(&queue->response_lock, flags);
if (cons == end)
break;
RING_COPY_REQUEST(&queue->tx, cons++, txp);
extra_count = 0; /* only the first frag can have extras */
} while (1);
queue->tx.req_cons = cons;
}
static void xenvif_fatal_tx_err(struct xenvif *vif)
{
netdev_err(vif->dev, "fatal error; disabling device\n");
vif->disabled = true;
/* Disable the vif from queue 0's kthread */
if (vif->num_queues)
xenvif_kick_thread(&vif->queues[0]);
}
static int xenvif_count_requests(struct xenvif_queue *queue,
struct xen_netif_tx_request *first,
unsigned int extra_count,
struct xen_netif_tx_request *txp,
int work_to_do)
{
RING_IDX cons = queue->tx.req_cons;
int slots = 0;
int drop_err = 0;
int more_data;
if (!(first->flags & XEN_NETTXF_more_data))
return 0;
do {
struct xen_netif_tx_request dropped_tx = { 0 };
if (slots >= work_to_do) {
netdev_err(queue->vif->dev,
"Asked for %d slots but exceeds this limit\n",
work_to_do);
xenvif_fatal_tx_err(queue->vif);
return -ENODATA;
}
/* This guest is really using too many slots and
* considered malicious.
*/
if (unlikely(slots >= fatal_skb_slots)) {
netdev_err(queue->vif->dev,
"Malicious frontend using %d slots, threshold %u\n",
slots, fatal_skb_slots);
xenvif_fatal_tx_err(queue->vif);
return -E2BIG;
}
/* Xen network protocol had implicit dependency on
* MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
* the historical MAX_SKB_FRAGS value 18 to honor the
* same behavior as before. Any packet using more than
* 18 slots but less than fatal_skb_slots slots is
* dropped
*/
if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
if (net_ratelimit())
netdev_dbg(queue->vif->dev,
"Too many slots (%d) exceeding limit (%d), dropping packet\n",
slots, XEN_NETBK_LEGACY_SLOTS_MAX);
drop_err = -E2BIG;
}
if (drop_err)
txp = &dropped_tx;
RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
/* If the guest submitted a frame >= 64 KiB then
* first->size overflowed and following slots will
* appear to be larger than the frame.
*
* This cannot be fatal error as there are buggy
* frontends that do this.
*
* Consume all slots and drop the packet.
*/
if (!drop_err && txp->size > first->size) {
if (net_ratelimit())
netdev_dbg(queue->vif->dev,
"Invalid tx request, slot size %u > remaining size %u\n",
txp->size, first->size);
drop_err = -EIO;
}
first->size -= txp->size;
slots++;
if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
txp->offset, txp->size);
xenvif_fatal_tx_err(queue->vif);
return -EINVAL;
}
more_data = txp->flags & XEN_NETTXF_more_data;
if (!drop_err)
txp++;
} while (more_data);
if (drop_err) {
xenvif_tx_err(queue, first, extra_count, cons + slots);
return drop_err;
}
return slots;
}
struct xenvif_tx_cb {
u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
u8 copy_count;
u32 split_mask;
};
#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
#define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
#define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
u16 pending_idx,
struct xen_netif_tx_request *txp,
unsigned int extra_count,
struct gnttab_map_grant_ref *mop)
{
queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
GNTMAP_host_map | GNTMAP_readonly,
txp->gref, queue->vif->domid);
memcpy(&queue->pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
queue->pending_tx_info[pending_idx].extra_count = extra_count;
}
static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
{
struct sk_buff *skb =
alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
GFP_ATOMIC | __GFP_NOWARN);
BUILD_BUG_ON(sizeof(*XENVIF_TX_CB(skb)) > sizeof(skb->cb));
if (unlikely(skb == NULL))
return NULL;
/* Packets passed to netif_rx() must have some headroom. */
skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
/* Initialize it here to avoid later surprises */
skb_shinfo(skb)->destructor_arg = NULL;
return skb;
}
static void xenvif_get_requests(struct xenvif_queue *queue,
struct sk_buff *skb,
struct xen_netif_tx_request *first,
struct xen_netif_tx_request *txfrags,
unsigned *copy_ops,
unsigned *map_ops,
unsigned int frag_overflow,
struct sk_buff *nskb,
unsigned int extra_count,
unsigned int data_len)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
skb_frag_t *frags = shinfo->frags;
u16 pending_idx;
pending_ring_idx_t index;
unsigned int nr_slots;
struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
struct xen_netif_tx_request *txp = first;
nr_slots = shinfo->nr_frags + 1;
copy_count(skb) = 0;
XENVIF_TX_CB(skb)->split_mask = 0;
/* Create copy ops for exactly data_len bytes into the skb head. */
__skb_put(skb, data_len);
while (data_len > 0) {
int amount = data_len > txp->size ? txp->size : data_len;
bool split = false;
cop->source.u.ref = txp->gref;
cop->source.domid = queue->vif->domid;
cop->source.offset = txp->offset;
cop->dest.domid = DOMID_SELF;
cop->dest.offset = (offset_in_page(skb->data +
skb_headlen(skb) -
data_len)) & ~XEN_PAGE_MASK;
cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
- data_len);
/* Don't cross local page boundary! */
if (cop->dest.offset + amount > XEN_PAGE_SIZE) {
amount = XEN_PAGE_SIZE - cop->dest.offset;
XENVIF_TX_CB(skb)->split_mask |= 1U << copy_count(skb);
split = true;
}
cop->len = amount;
cop->flags = GNTCOPY_source_gref;
index = pending_index(queue->pending_cons);
pending_idx = queue->pending_ring[index];
callback_param(queue, pending_idx).ctx = NULL;
copy_pending_idx(skb, copy_count(skb)) = pending_idx;
if (!split)
copy_count(skb)++;
cop++;
data_len -= amount;
if (amount == txp->size) {
/* The copy op covered the full tx_request */
memcpy(&queue->pending_tx_info[pending_idx].req,
txp, sizeof(*txp));
queue->pending_tx_info[pending_idx].extra_count =
(txp == first) ? extra_count : 0;
if (txp == first)
txp = txfrags;
else
txp++;
queue->pending_cons++;
nr_slots--;
} else {
/* The copy op partially covered the tx_request.
* The remainder will be mapped or copied in the next
* iteration.
*/
txp->offset += amount;
txp->size -= amount;
}
}
for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
shinfo->nr_frags++, gop++) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
xenvif_tx_create_map_op(queue, pending_idx, txp,
txp == first ? extra_count : 0, gop);
frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
if (txp == first)
txp = txfrags;
else
txp++;
}
if (frag_overflow) {
shinfo = skb_shinfo(nskb);
frags = shinfo->frags;
for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
shinfo->nr_frags++, txp++, gop++) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
gop);
frag_set_pending_idx(&frags[shinfo->nr_frags],
pending_idx);
}
skb_shinfo(skb)->frag_list = nskb;
}
(*copy_ops) = cop - queue->tx_copy_ops;
(*map_ops) = gop - queue->tx_map_ops;
}
static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
u16 pending_idx,
grant_handle_t handle)
{
if (unlikely(queue->grant_tx_handle[pending_idx] !=
NETBACK_INVALID_HANDLE)) {
netdev_err(queue->vif->dev,
"Trying to overwrite active handle! pending_idx: 0x%x\n",
pending_idx);
BUG();
}
queue->grant_tx_handle[pending_idx] = handle;
}
static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
u16 pending_idx)
{
if (unlikely(queue->grant_tx_handle[pending_idx] ==
NETBACK_INVALID_HANDLE)) {
netdev_err(queue->vif->dev,
"Trying to unmap invalid handle! pending_idx: 0x%x\n",
pending_idx);
BUG();
}
queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
}
static int xenvif_tx_check_gop(struct xenvif_queue *queue,
struct sk_buff *skb,
struct gnttab_map_grant_ref **gopp_map,
struct gnttab_copy **gopp_copy)
{
struct gnttab_map_grant_ref *gop_map = *gopp_map;
u16 pending_idx;
/* This always points to the shinfo of the skb being checked, which
* could be either the first or the one on the frag_list
*/
struct skb_shared_info *shinfo = skb_shinfo(skb);
/* If this is non-NULL, we are currently checking the frag_list skb, and
* this points to the shinfo of the first one
*/
struct skb_shared_info *first_shinfo = NULL;
int nr_frags = shinfo->nr_frags;
const bool sharedslot = nr_frags &&
frag_get_pending_idx(&shinfo->frags[0]) ==
copy_pending_idx(skb, copy_count(skb) - 1);
int i, err = 0;
for (i = 0; i < copy_count(skb); i++) {
int newerr;
/* Check status of header. */
pending_idx = copy_pending_idx(skb, i);
newerr = (*gopp_copy)->status;
/* Split copies need to be handled together. */
if (XENVIF_TX_CB(skb)->split_mask & (1U << i)) {
(*gopp_copy)++;
if (!newerr)
newerr = (*gopp_copy)->status;
}
if (likely(!newerr)) {
/* The first frag might still have this slot mapped */
if (i < copy_count(skb) - 1 || !sharedslot)
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_OKAY);
} else {
err = newerr;
if (net_ratelimit())
netdev_dbg(queue->vif->dev,
"Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
(*gopp_copy)->status,
pending_idx,
(*gopp_copy)->source.u.ref);
/* The first frag might still have this slot mapped */
if (i < copy_count(skb) - 1 || !sharedslot)
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_ERROR);
}
(*gopp_copy)++;
}
check_frags:
for (i = 0; i < nr_frags; i++, gop_map++) {
int j, newerr;
pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
/* Check error status: if okay then remember grant handle. */
newerr = gop_map->status;
if (likely(!newerr)) {
xenvif_grant_handle_set(queue,
pending_idx,
gop_map->handle);
/* Had a previous error? Invalidate this fragment. */
if (unlikely(err)) {
xenvif_idx_unmap(queue, pending_idx);
/* If the mapping of the first frag was OK, but
* the header's copy failed, and they are
* sharing a slot, send an error
*/
if (i == 0 && !first_shinfo && sharedslot)
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_ERROR);
else
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_OKAY);
}
continue;
}
/* Error on this fragment: respond to client with an error. */
if (net_ratelimit())
netdev_dbg(queue->vif->dev,
"Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
i,
gop_map->status,
pending_idx,
gop_map->ref);
xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
/* Not the first error? Preceding frags already invalidated. */
if (err)
continue;
/* Invalidate preceding fragments of this skb. */
for (j = 0; j < i; j++) {
pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
xenvif_idx_unmap(queue, pending_idx);
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_OKAY);
}
/* And if we found the error while checking the frag_list, unmap
* the first skb's frags
*/
if (first_shinfo) {
for (j = 0; j < first_shinfo->nr_frags; j++) {
pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
xenvif_idx_unmap(queue, pending_idx);
xenvif_idx_release(queue, pending_idx,
XEN_NETIF_RSP_OKAY);
}
}
/* Remember the error: invalidate all subsequent fragments. */
err = newerr;
}
if (skb_has_frag_list(skb) && !first_shinfo) {
first_shinfo = shinfo;
shinfo = skb_shinfo(shinfo->frag_list);
nr_frags = shinfo->nr_frags;
goto check_frags;
}
*gopp_map = gop_map;
return err;
}
static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
int nr_frags = shinfo->nr_frags;
int i;
u16 prev_pending_idx = INVALID_PENDING_IDX;
for (i = 0; i < nr_frags; i++) {
skb_frag_t *frag = shinfo->frags + i;
struct xen_netif_tx_request *txp;
struct page *page;
u16 pending_idx;
pending_idx = frag_get_pending_idx(frag);
/* If this is not the first frag, chain it to the previous*/
if (prev_pending_idx == INVALID_PENDING_IDX)
skb_shinfo(skb)->destructor_arg =
&callback_param(queue, pending_idx);
else
callback_param(queue, prev_pending_idx).ctx =
&callback_param(queue, pending_idx);
callback_param(queue, pending_idx).ctx = NULL;
prev_pending_idx = pending_idx;
txp = &queue->pending_tx_info[pending_idx].req;
page = virt_to_page((void *)idx_to_kaddr(queue, pending_idx));
__skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
skb->len += txp->size;
skb->data_len += txp->size;
skb->truesize += txp->size;
/* Take an extra reference to offset network stack's put_page */
get_page(queue->mmap_pages[pending_idx]);
}
}
static int xenvif_get_extras(struct xenvif_queue *queue,
struct xen_netif_extra_info *extras,
unsigned int *extra_count,
int work_to_do)
{
struct xen_netif_extra_info extra;
RING_IDX cons = queue->tx.req_cons;
do {
if (unlikely(work_to_do-- <= 0)) {
netdev_err(queue->vif->dev, "Missing extra info\n");
xenvif_fatal_tx_err(queue->vif);
return -EBADR;
}
RING_COPY_REQUEST(&queue->tx, cons, &extra);
queue->tx.req_cons = ++cons;
(*extra_count)++;
if (unlikely(!extra.type ||
extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
netdev_err(queue->vif->dev,
"Invalid extra type: %d\n", extra.type);
xenvif_fatal_tx_err(queue->vif);
return -EINVAL;
}
memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
return work_to_do;
}
static int xenvif_set_skb_gso(struct xenvif *vif,
struct sk_buff *skb,
struct xen_netif_extra_info *gso)
{
if (!gso->u.gso.size) {
netdev_err(vif->dev, "GSO size must not be zero.\n");
xenvif_fatal_tx_err(vif);
return -EINVAL;
}
switch (gso->u.gso.type) {
case XEN_NETIF_GSO_TYPE_TCPV4:
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
break;
case XEN_NETIF_GSO_TYPE_TCPV6:
skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
break;
default:
netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
xenvif_fatal_tx_err(vif);
return -EINVAL;
}
skb_shinfo(skb)->gso_size = gso->u.gso.size;
/* gso_segs will be calculated later */
return 0;
}
static int checksum_setup(struct xenvif_queue *queue, 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)) {
queue->stats.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 bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
{
u64 now = get_jiffies_64();
u64 next_credit = queue->credit_window_start +
msecs_to_jiffies(queue->credit_usec / 1000);
/* Timer could already be pending in rare cases. */
if (timer_pending(&queue->credit_timeout)) {
queue->rate_limited = true;
return true;
}
/* Passed the point where we can replenish credit? */
if (time_after_eq64(now, next_credit)) {
queue->credit_window_start = now;
tx_add_credit(queue);
}
/* Still too big to send right now? Set a callback. */
if (size > queue->remaining_credit) {
mod_timer(&queue->credit_timeout,
next_credit);
queue->credit_window_start = next_credit;
queue->rate_limited = true;
return true;
}
return false;
}
/* No locking is required in xenvif_mcast_add/del() as they are
* only ever invoked from NAPI poll. An RCU list is used because
* xenvif_mcast_match() is called asynchronously, during start_xmit.
*/
static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
{
struct xenvif_mcast_addr *mcast;
if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
if (net_ratelimit())
netdev_err(vif->dev,
"Too many multicast addresses\n");
return -ENOSPC;
}
mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
if (!mcast)
return -ENOMEM;
ether_addr_copy(mcast->addr, addr);
list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
vif->fe_mcast_count++;
return 0;
}
static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
{
struct xenvif_mcast_addr *mcast;
list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
if (ether_addr_equal(addr, mcast->addr)) {
--vif->fe_mcast_count;
list_del_rcu(&mcast->entry);
kfree_rcu(mcast, rcu);
break;
}
}
}
bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
{
struct xenvif_mcast_addr *mcast;
rcu_read_lock();
list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
if (ether_addr_equal(addr, mcast->addr)) {
rcu_read_unlock();
return true;
}
}
rcu_read_unlock();
return false;
}
void xenvif_mcast_addr_list_free(struct xenvif *vif)
{
/* No need for locking or RCU here. NAPI poll and TX queue
* are stopped.
*/
while (!list_empty(&vif->fe_mcast_addr)) {
struct xenvif_mcast_addr *mcast;
mcast = list_first_entry(&vif->fe_mcast_addr,
struct xenvif_mcast_addr,
entry);
--vif->fe_mcast_count;
list_del(&mcast->entry);
kfree(mcast);
}
}
static void xenvif_tx_build_gops(struct xenvif_queue *queue,
int budget,
unsigned *copy_ops,
unsigned *map_ops)
{
struct sk_buff *skb, *nskb;
int ret;
unsigned int frag_overflow;
while (skb_queue_len(&queue->tx_queue) < budget) {
struct xen_netif_tx_request txreq;
struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
unsigned int extra_count;
RING_IDX idx;
int work_to_do;
unsigned int data_len;
if (queue->tx.sring->req_prod - queue->tx.req_cons >
XEN_NETIF_TX_RING_SIZE) {
netdev_err(queue->vif->dev,
"Impossible number of requests. "
"req_prod %d, req_cons %d, size %ld\n",
queue->tx.sring->req_prod, queue->tx.req_cons,
XEN_NETIF_TX_RING_SIZE);
xenvif_fatal_tx_err(queue->vif);
break;
}
work_to_do = XEN_RING_NR_UNCONSUMED_REQUESTS(&queue->tx);
if (!work_to_do)
break;
idx = queue->tx.req_cons;
rmb(); /* Ensure that we see the request before we copy it. */
RING_COPY_REQUEST(&queue->tx, idx, &txreq);
/* Credit-based scheduling. */
if (txreq.size > queue->remaining_credit &&
tx_credit_exceeded(queue, txreq.size))
break;
queue->remaining_credit -= txreq.size;
work_to_do--;
queue->tx.req_cons = ++idx;
memset(extras, 0, sizeof(extras));
extra_count = 0;
if (txreq.flags & XEN_NETTXF_extra_info) {
work_to_do = xenvif_get_extras(queue, extras,
&extra_count,
work_to_do);
idx = queue->tx.req_cons;
if (unlikely(work_to_do < 0))
break;
}
if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
struct xen_netif_extra_info *extra;
extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
make_tx_response(queue, &txreq, extra_count,
(ret == 0) ?
XEN_NETIF_RSP_OKAY :
XEN_NETIF_RSP_ERROR);
push_tx_responses(queue);
continue;
}
if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
struct xen_netif_extra_info *extra;
extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
make_tx_response(queue, &txreq, extra_count,
XEN_NETIF_RSP_OKAY);
push_tx_responses(queue);
continue;
}
data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
XEN_NETBACK_TX_COPY_LEN : txreq.size;
ret = xenvif_count_requests(queue, &txreq, extra_count,
txfrags, work_to_do);
if (unlikely(ret < 0))
break;
idx += ret;
if (unlikely(txreq.size < ETH_HLEN)) {
netdev_dbg(queue->vif->dev,
"Bad packet size: %d\n", txreq.size);
xenvif_tx_err(queue, &txreq, extra_count, idx);
break;
}
/* No crossing a page as the payload mustn't fragment. */
if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
netdev_err(queue->vif->dev, "Cross page boundary, txreq.offset: %u, size: %u\n",
txreq.offset, txreq.size);
xenvif_fatal_tx_err(queue->vif);
break;