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OpenCloudOS-Kernel/net/core/gro.c

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// SPDX-License-Identifier: GPL-2.0-or-later
#include <net/gro.h>
#include <net/dst_metadata.h>
#include <net/busy_poll.h>
#include <trace/events/net.h>
#define MAX_GRO_SKBS 8
/* This should be increased if a protocol with a bigger head is added. */
#define GRO_MAX_HEAD (MAX_HEADER + 128)
static DEFINE_SPINLOCK(offload_lock);
static struct list_head offload_base __read_mostly = LIST_HEAD_INIT(offload_base);
/* Maximum number of GRO_NORMAL skbs to batch up for list-RX */
int gro_normal_batch __read_mostly = 8;
/**
* dev_add_offload - register offload handlers
* @po: protocol offload declaration
*
* Add protocol offload handlers to the networking stack. The passed
* &proto_offload is linked into kernel lists and may not be freed until
* it has been removed from the kernel lists.
*
* This call does not sleep therefore it can not
* guarantee all CPU's that are in middle of receiving packets
* will see the new offload handlers (until the next received packet).
*/
void dev_add_offload(struct packet_offload *po)
{
struct packet_offload *elem;
spin_lock(&offload_lock);
list_for_each_entry(elem, &offload_base, list) {
if (po->priority < elem->priority)
break;
}
list_add_rcu(&po->list, elem->list.prev);
spin_unlock(&offload_lock);
}
EXPORT_SYMBOL(dev_add_offload);
/**
* __dev_remove_offload - remove offload handler
* @po: packet offload declaration
*
* Remove a protocol offload handler that was previously added to the
* kernel offload handlers by dev_add_offload(). The passed &offload_type
* is removed from the kernel lists and can be freed or reused once this
* function returns.
*
* The packet type might still be in use by receivers
* and must not be freed until after all the CPU's have gone
* through a quiescent state.
*/
static void __dev_remove_offload(struct packet_offload *po)
{
struct list_head *head = &offload_base;
struct packet_offload *po1;
spin_lock(&offload_lock);
list_for_each_entry(po1, head, list) {
if (po == po1) {
list_del_rcu(&po->list);
goto out;
}
}
pr_warn("dev_remove_offload: %p not found\n", po);
out:
spin_unlock(&offload_lock);
}
/**
* dev_remove_offload - remove packet offload handler
* @po: packet offload declaration
*
* Remove a packet offload handler that was previously added to the kernel
* offload handlers by dev_add_offload(). The passed &offload_type is
* removed from the kernel lists and can be freed or reused once this
* function returns.
*
* This call sleeps to guarantee that no CPU is looking at the packet
* type after return.
*/
void dev_remove_offload(struct packet_offload *po)
{
__dev_remove_offload(po);
synchronize_net();
}
EXPORT_SYMBOL(dev_remove_offload);
/**
* skb_eth_gso_segment - segmentation handler for ethernet protocols.
* @skb: buffer to segment
* @features: features for the output path (see dev->features)
* @type: Ethernet Protocol ID
*/
struct sk_buff *skb_eth_gso_segment(struct sk_buff *skb,
netdev_features_t features, __be16 type)
{
struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
struct packet_offload *ptype;
rcu_read_lock();
list_for_each_entry_rcu(ptype, &offload_base, list) {
if (ptype->type == type && ptype->callbacks.gso_segment) {
segs = ptype->callbacks.gso_segment(skb, features);
break;
}
}
rcu_read_unlock();
return segs;
}
EXPORT_SYMBOL(skb_eth_gso_segment);
/**
* skb_mac_gso_segment - mac layer segmentation handler.
* @skb: buffer to segment
* @features: features for the output path (see dev->features)
*/
struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
struct packet_offload *ptype;
int vlan_depth = skb->mac_len;
__be16 type = skb_network_protocol(skb, &vlan_depth);
if (unlikely(!type))
return ERR_PTR(-EINVAL);
__skb_pull(skb, vlan_depth);
rcu_read_lock();
list_for_each_entry_rcu(ptype, &offload_base, list) {
if (ptype->type == type && ptype->callbacks.gso_segment) {
segs = ptype->callbacks.gso_segment(skb, features);
break;
}
}
rcu_read_unlock();
__skb_push(skb, skb->data - skb_mac_header(skb));
return segs;
}
EXPORT_SYMBOL(skb_mac_gso_segment);
int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
{
struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
unsigned int offset = skb_gro_offset(skb);
unsigned int headlen = skb_headlen(skb);
unsigned int len = skb_gro_len(skb);
unsigned int delta_truesize;
unsigned int gro_max_size;
unsigned int new_truesize;
struct sk_buff *lp;
int segs;
/* pairs with WRITE_ONCE() in netif_set_gro_max_size() */
gro_max_size = READ_ONCE(p->dev->gro_max_size);
if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush))
return -E2BIG;
if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) {
if (p->protocol != htons(ETH_P_IPV6) ||
skb_headroom(p) < sizeof(struct hop_jumbo_hdr) ||
ipv6_hdr(p)->nexthdr != IPPROTO_TCP ||
p->encapsulation)
return -E2BIG;
}
segs = NAPI_GRO_CB(skb)->count;
lp = NAPI_GRO_CB(p)->last;
pinfo = skb_shinfo(lp);
if (headlen <= offset) {
skb_frag_t *frag;
skb_frag_t *frag2;
int i = skbinfo->nr_frags;
int nr_frags = pinfo->nr_frags + i;
if (nr_frags > MAX_SKB_FRAGS)
goto merge;
offset -= headlen;
pinfo->nr_frags = nr_frags;
skbinfo->nr_frags = 0;
frag = pinfo->frags + nr_frags;
frag2 = skbinfo->frags + i;
do {
*--frag = *--frag2;
} while (--i);
skb_frag_off_add(frag, offset);
skb_frag_size_sub(frag, offset);
/* all fragments truesize : remove (head size + sk_buff) */
new_truesize = SKB_TRUESIZE(skb_end_offset(skb));
delta_truesize = skb->truesize - new_truesize;
skb->truesize = new_truesize;
skb->len -= skb->data_len;
skb->data_len = 0;
NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
goto done;
} else if (skb->head_frag) {
int nr_frags = pinfo->nr_frags;
skb_frag_t *frag = pinfo->frags + nr_frags;
struct page *page = virt_to_head_page(skb->head);
unsigned int first_size = headlen - offset;
unsigned int first_offset;
if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
goto merge;
first_offset = skb->data -
(unsigned char *)page_address(page) +
offset;
pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
__skb_frag_set_page(frag, page);
skb_frag_off_set(frag, first_offset);
skb_frag_size_set(frag, first_size);
memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
/* We dont need to clear skbinfo->nr_frags here */
new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
delta_truesize = skb->truesize - new_truesize;
skb->truesize = new_truesize;
NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
goto done;
}
merge:
/* sk owenrship - if any - completely transferred to the aggregated packet */
skb->destructor = NULL;
delta_truesize = skb->truesize;
if (offset > headlen) {
unsigned int eat = offset - headlen;
skb_frag_off_add(&skbinfo->frags[0], eat);
skb_frag_size_sub(&skbinfo->frags[0], eat);
skb->data_len -= eat;
skb->len -= eat;
offset = headlen;
}
__skb_pull(skb, offset);
if (NAPI_GRO_CB(p)->last == p)
skb_shinfo(p)->frag_list = skb;
else
NAPI_GRO_CB(p)->last->next = skb;
NAPI_GRO_CB(p)->last = skb;
__skb_header_release(skb);
lp = p;
done:
NAPI_GRO_CB(p)->count += segs;
p->data_len += len;
p->truesize += delta_truesize;
p->len += len;
if (lp != p) {
lp->data_len += len;
lp->truesize += delta_truesize;
lp->len += len;
}
NAPI_GRO_CB(skb)->same_flow = 1;
return 0;
}
static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb)
{
struct packet_offload *ptype;
__be16 type = skb->protocol;
struct list_head *head = &offload_base;
int err = -ENOENT;
BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
if (NAPI_GRO_CB(skb)->count == 1) {
skb_shinfo(skb)->gso_size = 0;
goto out;
}
rcu_read_lock();
list_for_each_entry_rcu(ptype, head, list) {
if (ptype->type != type || !ptype->callbacks.gro_complete)
continue;
err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
ipv6_gro_complete, inet_gro_complete,
skb, 0);
break;
}
rcu_read_unlock();
if (err) {
WARN_ON(&ptype->list == head);
kfree_skb(skb);
return;
}
out:
gro_normal_one(napi, skb, NAPI_GRO_CB(skb)->count);
}
static void __napi_gro_flush_chain(struct napi_struct *napi, u32 index,
bool flush_old)
{
struct list_head *head = &napi->gro_hash[index].list;
struct sk_buff *skb, *p;
list_for_each_entry_safe_reverse(skb, p, head, list) {
if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
return;
skb_list_del_init(skb);
napi_gro_complete(napi, skb);
napi->gro_hash[index].count--;
}
if (!napi->gro_hash[index].count)
__clear_bit(index, &napi->gro_bitmask);
}
/* napi->gro_hash[].list contains packets ordered by age.
* youngest packets at the head of it.
* Complete skbs in reverse order to reduce latencies.
*/
void napi_gro_flush(struct napi_struct *napi, bool flush_old)
{
unsigned long bitmask = napi->gro_bitmask;
unsigned int i, base = ~0U;
while ((i = ffs(bitmask)) != 0) {
bitmask >>= i;
base += i;
__napi_gro_flush_chain(napi, base, flush_old);
}
}
EXPORT_SYMBOL(napi_gro_flush);
static void gro_list_prepare(const struct list_head *head,
const struct sk_buff *skb)
{
unsigned int maclen = skb->dev->hard_header_len;
u32 hash = skb_get_hash_raw(skb);
struct sk_buff *p;
list_for_each_entry(p, head, list) {
unsigned long diffs;
NAPI_GRO_CB(p)->flush = 0;
if (hash != skb_get_hash_raw(p)) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
diffs |= p->vlan_all ^ skb->vlan_all;
diffs |= skb_metadata_differs(p, skb);
if (maclen == ETH_HLEN)
diffs |= compare_ether_header(skb_mac_header(p),
skb_mac_header(skb));
else if (!diffs)
diffs = memcmp(skb_mac_header(p),
skb_mac_header(skb),
maclen);
/* in most common scenarions 'slow_gro' is 0
* otherwise we are already on some slower paths
* either skip all the infrequent tests altogether or
* avoid trying too hard to skip each of them individually
*/
if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) {
#if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
struct tc_skb_ext *skb_ext;
struct tc_skb_ext *p_ext;
#endif
diffs |= p->sk != skb->sk;
diffs |= skb_metadata_dst_cmp(p, skb);
diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb);
#if IS_ENABLED(CONFIG_SKB_EXTENSIONS) && IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
skb_ext = skb_ext_find(skb, TC_SKB_EXT);
p_ext = skb_ext_find(p, TC_SKB_EXT);
diffs |= (!!p_ext) ^ (!!skb_ext);
if (!diffs && unlikely(skb_ext))
diffs |= p_ext->chain ^ skb_ext->chain;
#endif
}
NAPI_GRO_CB(p)->same_flow = !diffs;
}
}
static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff)
{
const struct skb_shared_info *pinfo = skb_shinfo(skb);
const skb_frag_t *frag0 = &pinfo->frags[0];
NAPI_GRO_CB(skb)->data_offset = 0;
NAPI_GRO_CB(skb)->frag0 = NULL;
NAPI_GRO_CB(skb)->frag0_len = 0;
if (!skb_headlen(skb) && pinfo->nr_frags &&
!PageHighMem(skb_frag_page(frag0)) &&
(!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) {
NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0);
NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int,
skb_frag_size(frag0),
skb->end - skb->tail);
}
}
static void gro_pull_from_frag0(struct sk_buff *skb, int grow)
{
struct skb_shared_info *pinfo = skb_shinfo(skb);
BUG_ON(skb->end - skb->tail < grow);
memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow);
skb->data_len -= grow;
skb->tail += grow;
skb_frag_off_add(&pinfo->frags[0], grow);
skb_frag_size_sub(&pinfo->frags[0], grow);
if (unlikely(!skb_frag_size(&pinfo->frags[0]))) {
skb_frag_unref(skb, 0);
memmove(pinfo->frags, pinfo->frags + 1,
--pinfo->nr_frags * sizeof(pinfo->frags[0]));
}
}
static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head)
{
struct sk_buff *oldest;
oldest = list_last_entry(head, struct sk_buff, list);
/* We are called with head length >= MAX_GRO_SKBS, so this is
* impossible.
*/
if (WARN_ON_ONCE(!oldest))
return;
/* Do not adjust napi->gro_hash[].count, caller is adding a new
* SKB to the chain.
*/
skb_list_del_init(oldest);
napi_gro_complete(napi, oldest);
}
static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
struct gro_list *gro_list = &napi->gro_hash[bucket];
struct list_head *head = &offload_base;
struct packet_offload *ptype;
__be16 type = skb->protocol;
struct sk_buff *pp = NULL;
enum gro_result ret;
int same_flow;
int grow;
if (netif_elide_gro(skb->dev))
goto normal;
gro_list_prepare(&gro_list->list, skb);
rcu_read_lock();
list_for_each_entry_rcu(ptype, head, list) {
if (ptype->type == type && ptype->callbacks.gro_receive)
goto found_ptype;
}
rcu_read_unlock();
goto normal;
found_ptype:
skb_set_network_header(skb, skb_gro_offset(skb));
skb_reset_mac_len(skb);
BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
sizeof(u32))); /* Avoid slow unaligned acc */
*(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
NAPI_GRO_CB(skb)->is_atomic = 1;
NAPI_GRO_CB(skb)->count = 1;
if (unlikely(skb_is_gso(skb))) {
NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
/* Only support TCP and non DODGY users. */
if (!skb_is_gso_tcp(skb) ||
(skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
NAPI_GRO_CB(skb)->flush = 1;
}
/* Setup for GRO checksum validation */
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
NAPI_GRO_CB(skb)->csum = skb->csum;
NAPI_GRO_CB(skb)->csum_valid = 1;
break;
case CHECKSUM_UNNECESSARY:
NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
break;
}
pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
ipv6_gro_receive, inet_gro_receive,
&gro_list->list, skb);
rcu_read_unlock();
if (PTR_ERR(pp) == -EINPROGRESS) {
ret = GRO_CONSUMED;
goto ok;
}
same_flow = NAPI_GRO_CB(skb)->same_flow;
ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;
if (pp) {
skb_list_del_init(pp);
napi_gro_complete(napi, pp);
gro_list->count--;
}
if (same_flow)
goto ok;
if (NAPI_GRO_CB(skb)->flush)
goto normal;
if (unlikely(gro_list->count >= MAX_GRO_SKBS))
gro_flush_oldest(napi, &gro_list->list);
else
gro_list->count++;
NAPI_GRO_CB(skb)->age = jiffies;
NAPI_GRO_CB(skb)->last = skb;
if (!skb_is_gso(skb))
skb_shinfo(skb)->gso_size = skb_gro_len(skb);
list_add(&skb->list, &gro_list->list);
ret = GRO_HELD;
pull:
grow = skb_gro_offset(skb) - skb_headlen(skb);
if (grow > 0)
gro_pull_from_frag0(skb, grow);
ok:
if (gro_list->count) {
if (!test_bit(bucket, &napi->gro_bitmask))
__set_bit(bucket, &napi->gro_bitmask);
} else if (test_bit(bucket, &napi->gro_bitmask)) {
__clear_bit(bucket, &napi->gro_bitmask);
}
return ret;
normal:
ret = GRO_NORMAL;
goto pull;
}
struct packet_offload *gro_find_receive_by_type(__be16 type)
{
struct list_head *offload_head = &offload_base;
struct packet_offload *ptype;
list_for_each_entry_rcu(ptype, offload_head, list) {
if (ptype->type != type || !ptype->callbacks.gro_receive)
continue;
return ptype;
}
return NULL;
}
EXPORT_SYMBOL(gro_find_receive_by_type);
struct packet_offload *gro_find_complete_by_type(__be16 type)
{
struct list_head *offload_head = &offload_base;
struct packet_offload *ptype;
list_for_each_entry_rcu(ptype, offload_head, list) {
if (ptype->type != type || !ptype->callbacks.gro_complete)
continue;
return ptype;
}
return NULL;
}
EXPORT_SYMBOL(gro_find_complete_by_type);
static gro_result_t napi_skb_finish(struct napi_struct *napi,
struct sk_buff *skb,
gro_result_t ret)
{
switch (ret) {
case GRO_NORMAL:
gro_normal_one(napi, skb, 1);
break;
case GRO_MERGED_FREE:
if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
napi_skb_free_stolen_head(skb);
else if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
__kfree_skb(skb);
else
__kfree_skb_defer(skb);
break;
case GRO_HELD:
case GRO_MERGED:
case GRO_CONSUMED:
break;
}
return ret;
}
gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
gro_result_t ret;
skb_mark_napi_id(skb, napi);
trace_napi_gro_receive_entry(skb);
skb_gro_reset_offset(skb, 0);
ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb));
trace_napi_gro_receive_exit(ret);
return ret;
}
EXPORT_SYMBOL(napi_gro_receive);
static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
{
if (unlikely(skb->pfmemalloc)) {
consume_skb(skb);
return;
}
__skb_pull(skb, skb_headlen(skb));
/* restore the reserve we had after netdev_alloc_skb_ip_align() */
skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb));
__vlan_hwaccel_clear_tag(skb);
skb->dev = napi->dev;
skb->skb_iif = 0;
/* eth_type_trans() assumes pkt_type is PACKET_HOST */
skb->pkt_type = PACKET_HOST;
skb->encapsulation = 0;
skb_shinfo(skb)->gso_type = 0;
skb_shinfo(skb)->gso_size = 0;
if (unlikely(skb->slow_gro)) {
skb_orphan(skb);
skb_ext_reset(skb);
nf_reset_ct(skb);
skb->slow_gro = 0;
}
napi->skb = skb;
}
struct sk_buff *napi_get_frags(struct napi_struct *napi)
{
struct sk_buff *skb = napi->skb;
if (!skb) {
skb = napi_alloc_skb(napi, GRO_MAX_HEAD);
if (skb) {
napi->skb = skb;
skb_mark_napi_id(skb, napi);
}
}
return skb;
}
EXPORT_SYMBOL(napi_get_frags);
static gro_result_t napi_frags_finish(struct napi_struct *napi,
struct sk_buff *skb,
gro_result_t ret)
{
switch (ret) {
case GRO_NORMAL:
case GRO_HELD:
__skb_push(skb, ETH_HLEN);
skb->protocol = eth_type_trans(skb, skb->dev);
if (ret == GRO_NORMAL)
gro_normal_one(napi, skb, 1);
break;
case GRO_MERGED_FREE:
if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
napi_skb_free_stolen_head(skb);
else
napi_reuse_skb(napi, skb);
break;
case GRO_MERGED:
case GRO_CONSUMED:
break;
}
return ret;
}
/* Upper GRO stack assumes network header starts at gro_offset=0
* Drivers could call both napi_gro_frags() and napi_gro_receive()
* We copy ethernet header into skb->data to have a common layout.
*/
static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
{
struct sk_buff *skb = napi->skb;
const struct ethhdr *eth;
unsigned int hlen = sizeof(*eth);
napi->skb = NULL;
skb_reset_mac_header(skb);
skb_gro_reset_offset(skb, hlen);
if (unlikely(skb_gro_header_hard(skb, hlen))) {
eth = skb_gro_header_slow(skb, hlen, 0);
if (unlikely(!eth)) {
net_warn_ratelimited("%s: dropping impossible skb from %s\n",
__func__, napi->dev->name);
napi_reuse_skb(napi, skb);
return NULL;
}
} else {
eth = (const struct ethhdr *)skb->data;
gro_pull_from_frag0(skb, hlen);
NAPI_GRO_CB(skb)->frag0 += hlen;
NAPI_GRO_CB(skb)->frag0_len -= hlen;
}
__skb_pull(skb, hlen);
/*
* This works because the only protocols we care about don't require
* special handling.
* We'll fix it up properly in napi_frags_finish()
*/
skb->protocol = eth->h_proto;
return skb;
}
gro_result_t napi_gro_frags(struct napi_struct *napi)
{
gro_result_t ret;
struct sk_buff *skb = napi_frags_skb(napi);
trace_napi_gro_frags_entry(skb);
ret = napi_frags_finish(napi, skb, dev_gro_receive(napi, skb));
trace_napi_gro_frags_exit(ret);
return ret;
}
EXPORT_SYMBOL(napi_gro_frags);
/* Compute the checksum from gro_offset and return the folded value
* after adding in any pseudo checksum.
*/
__sum16 __skb_gro_checksum_complete(struct sk_buff *skb)
{
__wsum wsum;
__sum16 sum;
wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0);
/* NAPI_GRO_CB(skb)->csum holds pseudo checksum */
sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum));
/* See comments in __skb_checksum_complete(). */
if (likely(!sum)) {
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
!skb->csum_complete_sw)
netdev_rx_csum_fault(skb->dev, skb);
}
NAPI_GRO_CB(skb)->csum = wsum;
NAPI_GRO_CB(skb)->csum_valid = 1;
return sum;
}
EXPORT_SYMBOL(__skb_gro_checksum_complete);
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