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#include <linux/skbuff.h>
#include <linux/export.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/if_tunnel.h>
#include <linux/if_pppox.h>
#include <linux/ppp_defs.h>
#include <net/flow_keys.h>
/* copy saddr & daddr, possibly using 64bit load/store
* Equivalent to : flow->src = iph->saddr;
* flow->dst = iph->daddr;
*/
static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph)
{
BUILD_BUG_ON(offsetof(typeof(*flow), dst) !=
offsetof(typeof(*flow), src) + sizeof(flow->src));
memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst));
}
bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
{
int poff, nhoff = skb_network_offset(skb);
u8 ip_proto;
__be16 proto = skb->protocol;
memset(flow, 0, sizeof(*flow));
again:
switch (proto) {
case __constant_htons(ETH_P_IP): {
const struct iphdr *iph;
struct iphdr _iph;
ip:
iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
if (!iph)
return false;
if (ip_is_fragment(iph))
ip_proto = 0;
else
ip_proto = iph->protocol;
iph_to_flow_copy_addrs(flow, iph);
nhoff += iph->ihl * 4;
break;
}
case __constant_htons(ETH_P_IPV6): {
const struct ipv6hdr *iph;
struct ipv6hdr _iph;
ipv6:
iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
if (!iph)
return false;
ip_proto = iph->nexthdr;
flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
nhoff += sizeof(struct ipv6hdr);
break;
}
case __constant_htons(ETH_P_8021Q): {
const struct vlan_hdr *vlan;
struct vlan_hdr _vlan;
vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan);
if (!vlan)
return false;
proto = vlan->h_vlan_encapsulated_proto;
nhoff += sizeof(*vlan);
goto again;
}
case __constant_htons(ETH_P_PPP_SES): {
struct {
struct pppoe_hdr hdr;
__be16 proto;
} *hdr, _hdr;
hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
if (!hdr)
return false;
proto = hdr->proto;
nhoff += PPPOE_SES_HLEN;
switch (proto) {
case __constant_htons(PPP_IP):
goto ip;
case __constant_htons(PPP_IPV6):
goto ipv6;
default:
return false;
}
}
default:
return false;
}
switch (ip_proto) {
case IPPROTO_GRE: {
struct gre_hdr {
__be16 flags;
__be16 proto;
} *hdr, _hdr;
hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
if (!hdr)
return false;
/*
* Only look inside GRE if version zero and no
* routing
*/
if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
proto = hdr->proto;
nhoff += 4;
if (hdr->flags & GRE_CSUM)
nhoff += 4;
if (hdr->flags & GRE_KEY)
nhoff += 4;
if (hdr->flags & GRE_SEQ)
nhoff += 4;
goto again;
}
break;
}
case IPPROTO_IPIP:
goto again;
default:
break;
}
flow->ip_proto = ip_proto;
poff = proto_ports_offset(ip_proto);
if (poff >= 0) {
__be32 *ports, _ports;
nhoff += poff;
ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports);
if (ports)
flow->ports = *ports;
}
flow->thoff = (u16) nhoff;
return true;
}
EXPORT_SYMBOL(skb_flow_dissect);
static u32 hashrnd __read_mostly;
/*
* __skb_get_rxhash: calculate a flow hash based on src/dst addresses
* and src/dst port numbers. Sets rxhash in skb to non-zero hash value
* on success, zero indicates no valid hash. Also, sets l4_rxhash in skb
* if hash is a canonical 4-tuple hash over transport ports.
*/
void __skb_get_rxhash(struct sk_buff *skb)
{
struct flow_keys keys;
u32 hash;
if (!skb_flow_dissect(skb, &keys))
return;
if (keys.ports)
skb->l4_rxhash = 1;
/* get a consistent hash (same value on both flow directions) */
if (((__force u32)keys.dst < (__force u32)keys.src) ||
(((__force u32)keys.dst == (__force u32)keys.src) &&
((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) {
swap(keys.dst, keys.src);
swap(keys.port16[0], keys.port16[1]);
}
hash = jhash_3words((__force u32)keys.dst,
(__force u32)keys.src,
(__force u32)keys.ports, hashrnd);
if (!hash)
hash = 1;
skb->rxhash = hash;
}
EXPORT_SYMBOL(__skb_get_rxhash);
/*
* Returns a Tx hash based on the given packet descriptor a Tx queues' number
* to be used as a distribution range.
*/
u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
unsigned int num_tx_queues)
{
u32 hash;
u16 qoffset = 0;
u16 qcount = num_tx_queues;
if (skb_rx_queue_recorded(skb)) {
hash = skb_get_rx_queue(skb);
while (unlikely(hash >= num_tx_queues))
hash -= num_tx_queues;
return hash;
}
if (dev->num_tc) {
u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
qoffset = dev->tc_to_txq[tc].offset;
qcount = dev->tc_to_txq[tc].count;
}
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol;
hash = jhash_1word(hash, hashrnd);
return (u16) (((u64) hash * qcount) >> 32) + qoffset;
}
EXPORT_SYMBOL(__skb_tx_hash);
static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
{
if (unlikely(queue_index >= dev->real_num_tx_queues)) {
net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n",
dev->name, queue_index,
dev->real_num_tx_queues);
return 0;
}
return queue_index;
}
static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
{
#ifdef CONFIG_XPS
struct xps_dev_maps *dev_maps;
struct xps_map *map;
int queue_index = -1;
rcu_read_lock();
dev_maps = rcu_dereference(dev->xps_maps);
if (dev_maps) {
map = rcu_dereference(
dev_maps->cpu_map[raw_smp_processor_id()]);
if (map) {
if (map->len == 1)
queue_index = map->queues[0];
else {
u32 hash;
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol ^
skb->rxhash;
hash = jhash_1word(hash, hashrnd);
queue_index = map->queues[
((u64)hash * map->len) >> 32];
}
if (unlikely(queue_index >= dev->real_num_tx_queues))
queue_index = -1;
}
}
rcu_read_unlock();
return queue_index;
#else
return -1;
#endif
}
u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
{
struct sock *sk = skb->sk;
int queue_index = sk_tx_queue_get(sk);
if (queue_index < 0 || skb->ooo_okay ||
queue_index >= dev->real_num_tx_queues) {
int new_index = get_xps_queue(dev, skb);
if (new_index < 0)
new_index = skb_tx_hash(dev, skb);
if (queue_index != new_index && sk) {
struct dst_entry *dst =
rcu_dereference_check(sk->sk_dst_cache, 1);
if (dst && skb_dst(skb) == dst)
sk_tx_queue_set(sk, queue_index);
}
queue_index = new_index;
}
return queue_index;
}
EXPORT_SYMBOL(__netdev_pick_tx);
struct netdev_queue *netdev_pick_tx(struct net_device *dev,
struct sk_buff *skb)
{
int queue_index = 0;
if (dev->real_num_tx_queues != 1) {
const struct net_device_ops *ops = dev->netdev_ops;
if (ops->ndo_select_queue)
queue_index = ops->ndo_select_queue(dev, skb);
else
queue_index = __netdev_pick_tx(dev, skb);
queue_index = dev_cap_txqueue(dev, queue_index);
}
skb_set_queue_mapping(skb, queue_index);
return netdev_get_tx_queue(dev, queue_index);
}
static int __init initialize_hashrnd(void)
{
get_random_bytes(&hashrnd, sizeof(hashrnd));
return 0;
}
late_initcall_sync(initialize_hashrnd);
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