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alistair23-linux/include/net/dst.h
Benedict Wong bc56b33404 xfrm: Remove xfrmi interface ID from flowi 
In order to remove performance impact of having the extra u32 in every
single flowi, this change removes the flowi_xfrm struct, prefering to
take the if_id as a method parameter where needed.

In the inbound direction, if_id is only needed during the
__xfrm_check_policy() function, and the if_id can be determined at that
point based on the skb. As such, xfrmi_decode_session() is only called
with the skb in __xfrm_check_policy().

In the outbound direction, the only place where if_id is needed is the
xfrm_lookup() call in xfrmi_xmit2(). With this change, the if_id is
directly passed into the xfrm_lookup_with_ifid() call. All existing
callers can still call xfrm_lookup(), which uses a default if_id of 0.

This change does not change any behavior of XFRMIs except for improving
overall system performance via flowi size reduction.

This change has been tested against the Android Kernel Networking Tests:

https://android.googlesource.com/kernel/tests/+/master/net/test

Signed-off-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2018-07-20 10:14:41 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* net/dst.h Protocol independent destination cache definitions.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#ifndef _NET_DST_H
#define _NET_DST_H
#include <net/dst_ops.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/rcupdate.h>
#include <linux/bug.h>
#include <linux/jiffies.h>
#include <linux/refcount.h>
#include <net/neighbour.h>
#include <asm/processor.h>
#define DST_GC_MIN (HZ/10)
#define DST_GC_INC (HZ/2)
#define DST_GC_MAX (120*HZ)
/* Each dst_entry has reference count and sits in some parent list(s).
* When it is removed from parent list, it is "freed" (dst_free).
* After this it enters dead state (dst->obsolete > 0) and if its refcnt
* is zero, it can be destroyed immediately, otherwise it is added
* to gc list and garbage collector periodically checks the refcnt.
*/
struct sk_buff;
struct dst_entry {
struct net_device *dev;
struct dst_ops *ops;
unsigned long _metrics;
unsigned long expires;
#ifdef CONFIG_XFRM
struct xfrm_state *xfrm;
#else
void *__pad1;
#endif
int (*input)(struct sk_buff *);
int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
unsigned short flags;
#define DST_HOST 0x0001
#define DST_NOXFRM 0x0002
#define DST_NOPOLICY 0x0004
#define DST_NOCOUNT 0x0008
#define DST_FAKE_RTABLE 0x0010
#define DST_XFRM_TUNNEL 0x0020
#define DST_XFRM_QUEUE 0x0040
#define DST_METADATA 0x0080
/* A non-zero value of dst->obsolete forces by-hand validation
* of the route entry. Positive values are set by the generic
* dst layer to indicate that the entry has been forcefully
* destroyed.
*
* Negative values are used by the implementation layer code to
* force invocation of the dst_ops->check() method.
*/
short obsolete;
#define DST_OBSOLETE_NONE 0
#define DST_OBSOLETE_DEAD 2
#define DST_OBSOLETE_FORCE_CHK -1
#define DST_OBSOLETE_KILL -2
unsigned short header_len; /* more space at head required */
unsigned short trailer_len; /* space to reserve at tail */
/*
* __refcnt wants to be on a different cache line from
* input/output/ops or performance tanks badly
*/
#ifdef CONFIG_64BIT
atomic_t __refcnt; /* 64-bit offset 64 */
#endif
int __use;
unsigned long lastuse;
struct lwtunnel_state *lwtstate;
struct rcu_head rcu_head;
short error;
short __pad;
__u32 tclassid;
#ifndef CONFIG_64BIT
atomic_t __refcnt; /* 32-bit offset 64 */
#endif
};
struct dst_metrics {
u32 metrics[RTAX_MAX];
refcount_t refcnt;
};
extern const struct dst_metrics dst_default_metrics;
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
#define DST_METRICS_READ_ONLY 0x1UL
#define DST_METRICS_REFCOUNTED 0x2UL
#define DST_METRICS_FLAGS 0x3UL
#define __DST_METRICS_PTR(Y) \
((u32 *)((Y) & ~DST_METRICS_FLAGS))
#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
static inline bool dst_metrics_read_only(const struct dst_entry *dst)
{
return dst->_metrics & DST_METRICS_READ_ONLY;
}
void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
{
unsigned long val = dst->_metrics;
if (!(val & DST_METRICS_READ_ONLY))
__dst_destroy_metrics_generic(dst, val);
}
static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
{
unsigned long p = dst->_metrics;
BUG_ON(!p);
if (p & DST_METRICS_READ_ONLY)
return dst->ops->cow_metrics(dst, p);
return __DST_METRICS_PTR(p);
}
/* This may only be invoked before the entry has reached global
* visibility.
*/
static inline void dst_init_metrics(struct dst_entry *dst,
const u32 *src_metrics,
bool read_only)
{
dst->_metrics = ((unsigned long) src_metrics) |
(read_only ? DST_METRICS_READ_ONLY : 0);
}
static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
{
u32 *dst_metrics = dst_metrics_write_ptr(dest);
if (dst_metrics) {
u32 *src_metrics = DST_METRICS_PTR(src);
memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
}
}
static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
{
return DST_METRICS_PTR(dst);
}
static inline u32
dst_metric_raw(const struct dst_entry *dst, const int metric)
{
u32 *p = DST_METRICS_PTR(dst);
return p[metric-1];
}
static inline u32
dst_metric(const struct dst_entry *dst, const int metric)
{
WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
metric == RTAX_ADVMSS ||
metric == RTAX_MTU);
return dst_metric_raw(dst, metric);
}
static inline u32
dst_metric_advmss(const struct dst_entry *dst)
{
u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
if (!advmss)
advmss = dst->ops->default_advmss(dst);
return advmss;
}
static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
{
u32 *p = dst_metrics_write_ptr(dst);
if (p)
p[metric-1] = val;
}
/* Kernel-internal feature bits that are unallocated in user space. */
#define DST_FEATURE_ECN_CA (1 << 31)
#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
static inline u32
dst_feature(const struct dst_entry *dst, u32 feature)
{
return dst_metric(dst, RTAX_FEATURES) & feature;
}
static inline u32 dst_mtu(const struct dst_entry *dst)
{
return dst->ops->mtu(dst);
}
/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
{
return msecs_to_jiffies(dst_metric(dst, metric));
}
static inline u32
dst_allfrag(const struct dst_entry *dst)
{
int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
return ret;
}
static inline int
dst_metric_locked(const struct dst_entry *dst, int metric)
{
return dst_metric(dst, RTAX_LOCK) & (1<<metric);
}
static inline void dst_hold(struct dst_entry *dst)
{
/*
* If your kernel compilation stops here, please check
* the placement of __refcnt in struct dst_entry
*/
BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
}
static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
{
if (unlikely(time != dst->lastuse)) {
dst->__use++;
dst->lastuse = time;
}
}
static inline void dst_hold_and_use(struct dst_entry *dst, unsigned long time)
{
dst_hold(dst);
dst_use_noref(dst, time);
}
static inline struct dst_entry *dst_clone(struct dst_entry *dst)
{
if (dst)
dst_hold(dst);
return dst;
}
void dst_release(struct dst_entry *dst);
void dst_release_immediate(struct dst_entry *dst);
static inline void refdst_drop(unsigned long refdst)
{
if (!(refdst & SKB_DST_NOREF))
dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
}
/**
* skb_dst_drop - drops skb dst
* @skb: buffer
*
* Drops dst reference count if a reference was taken.
*/
static inline void skb_dst_drop(struct sk_buff *skb)
{
if (skb->_skb_refdst) {
refdst_drop(skb->_skb_refdst);
skb->_skb_refdst = 0UL;
}
}
static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
{
nskb->_skb_refdst = refdst;
if (!(nskb->_skb_refdst & SKB_DST_NOREF))
dst_clone(skb_dst(nskb));
}
static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
{
__skb_dst_copy(nskb, oskb->_skb_refdst);
}
/**
* dst_hold_safe - Take a reference on a dst if possible
* @dst: pointer to dst entry
*
* This helper returns false if it could not safely
* take a reference on a dst.
*/
static inline bool dst_hold_safe(struct dst_entry *dst)
{
return atomic_inc_not_zero(&dst->__refcnt);
}
/**
* skb_dst_force - makes sure skb dst is refcounted
* @skb: buffer
*
* If dst is not yet refcounted and not destroyed, grab a ref on it.
*/
static inline void skb_dst_force(struct sk_buff *skb)
{
if (skb_dst_is_noref(skb)) {
struct dst_entry *dst = skb_dst(skb);
WARN_ON(!rcu_read_lock_held());
if (!dst_hold_safe(dst))
dst = NULL;
skb->_skb_refdst = (unsigned long)dst;
}
}
/**
* __skb_tunnel_rx - prepare skb for rx reinsert
* @skb: buffer
* @dev: tunnel device
* @net: netns for packet i/o
*
* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
* so make some cleanups. (no accounting done)
*/
static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
struct net *net)
{
skb->dev = dev;
/*
* Clear hash so that we can recalulate the hash for the
* encapsulated packet, unless we have already determine the hash
* over the L4 4-tuple.
*/
skb_clear_hash_if_not_l4(skb);
skb_set_queue_mapping(skb, 0);
skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
}
/**
* skb_tunnel_rx - prepare skb for rx reinsert
* @skb: buffer
* @dev: tunnel device
* @net: netns for packet i/o
*
* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
* so make some cleanups, and perform accounting.
* Note: this accounting is not SMP safe.
*/
static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
struct net *net)
{
/* TODO : stats should be SMP safe */
dev->stats.rx_packets++;
dev->stats.rx_bytes += skb->len;
__skb_tunnel_rx(skb, dev, net);
}
static inline u32 dst_tclassid(const struct sk_buff *skb)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
const struct dst_entry *dst;
dst = skb_dst(skb);
if (dst)
return dst->tclassid;
#endif
return 0;
}
int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
static inline int dst_discard(struct sk_buff *skb)
{
return dst_discard_out(&init_net, skb->sk, skb);
}
void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
int initial_obsolete, unsigned short flags);
void dst_init(struct dst_entry *dst, struct dst_ops *ops,
struct net_device *dev, int initial_ref, int initial_obsolete,
unsigned short flags);
struct dst_entry *dst_destroy(struct dst_entry *dst);
void dst_dev_put(struct dst_entry *dst);
static inline void dst_confirm(struct dst_entry *dst)
{
}
static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
{
struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
return IS_ERR(n) ? NULL : n;
}
static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
struct sk_buff *skb)
{
struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
return IS_ERR(n) ? NULL : n;
}
static inline void dst_confirm_neigh(const struct dst_entry *dst,
const void *daddr)
{
if (dst->ops->confirm_neigh)
dst->ops->confirm_neigh(dst, daddr);
}
static inline void dst_link_failure(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
if (dst && dst->ops && dst->ops->link_failure)
dst->ops->link_failure(skb);
}
static inline void dst_set_expires(struct dst_entry *dst, int timeout)
{
unsigned long expires = jiffies + timeout;
if (expires == 0)
expires = 1;
if (dst->expires == 0 || time_before(expires, dst->expires))
dst->expires = expires;
}
/* Output packet to network from transport. */
static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return skb_dst(skb)->output(net, sk, skb);
}
/* Input packet from network to transport. */
static inline int dst_input(struct sk_buff *skb)
{
return skb_dst(skb)->input(skb);
}
static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
{
if (dst->obsolete)
dst = dst->ops->check(dst, cookie);
return dst;
}
/* Flags for xfrm_lookup flags argument. */
enum {
XFRM_LOOKUP_ICMP = 1 << 0,
XFRM_LOOKUP_QUEUE = 1 << 1,
XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
};
struct flowi;
#ifndef CONFIG_XFRM
static inline struct dst_entry *xfrm_lookup(struct net *net,
struct dst_entry *dst_orig,
const struct flowi *fl,
const struct sock *sk,
int flags)
{
return dst_orig;
}
static inline struct dst_entry *
xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl, const struct sock *sk,
int flags, u32 if_id)
{
return dst_orig;
}
static inline struct dst_entry *xfrm_lookup_route(struct net *net,
struct dst_entry *dst_orig,
const struct flowi *fl,
const struct sock *sk,
int flags)
{
return dst_orig;
}
static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
return NULL;
}
#else
struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl, const struct sock *sk,
int flags);
struct dst_entry *xfrm_lookup_with_ifid(struct net *net,
struct dst_entry *dst_orig,
const struct flowi *fl,
const struct sock *sk, int flags,
u32 if_id);
struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
const struct flowi *fl, const struct sock *sk,
int flags);
/* skb attached with this dst needs transformation if dst->xfrm is valid */
static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
{
return dst->xfrm;
}
#endif
static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
{
struct dst_entry *dst = skb_dst(skb);
if (dst && dst->ops->update_pmtu)
dst->ops->update_pmtu(dst, NULL, skb, mtu);
}
#endif /* _NET_DST_H */
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